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Mu Y, Zhang N, Wei D, Yang G, Yao L, Xu X, Li Y, Xue J, Zhang Z, Chen T. Müller cells are activated in response to retinal outer nuclear layer degeneration in rats subjected to simulated weightlessness conditions. Neural Regen Res 2025; 20:2116-2128. [PMID: 39254570 PMCID: PMC11691450 DOI: 10.4103/nrr.nrr-d-23-01035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 10/25/2023] [Accepted: 01/07/2024] [Indexed: 09/11/2024] Open
Abstract
JOURNAL/nrgr/04.03/01300535-202507000-00032/figure1/v/2024-09-09T124005Z/r/image-tiff A microgravity environment has been shown to cause ocular damage and affect visual acuity, but the underlying mechanisms remain unclear. Therefore, we established an animal model of weightlessness via tail suspension to examine the pathological changes and molecular mechanisms of retinal damage under microgravity. After 4 weeks of tail suspension, there were no notable alterations in retinal function and morphology, while after 8 weeks of tail suspension, significant reductions in retinal function were observed, and the outer nuclear layer was thinner, with abundant apoptotic cells. To investigate the mechanism underlying the degenerative changes that occurred in the outer nuclear layer of the retina, proteomics was used to analyze differentially expressed proteins in rat retinas after 8 weeks of tail suspension. The results showed that the expression levels of fibroblast growth factor 2 (also known as basic fibroblast growth factor) and glial fibrillary acidic protein, which are closely related to Müller cell activation, were significantly upregulated. In addition, Müller cell regeneration and Müller cell gliosis were observed after 4 and 8 weeks, respectively, of simulated weightlessness. These findings indicate that Müller cells play an important regulatory role in retinal outer nuclear layer degeneration during weightlessness.
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Affiliation(s)
- Yuxue Mu
- Aerospace Clinical Medical Center, School of Aerospace Medicine, Air Force Medical University, Xi’an, Shaanxi Province, China
- Department of Aviation Medicine, Xijing Hospital, Air Force Medical University, Xi’an, Shaanxi Province, China
| | - Ning Zhang
- Department of Emergency Medicine, Wuhan No.1 Hospital, Wuhan, Hubei Province, China
| | - Dongyu Wei
- Aerospace Clinical Medical Center, School of Aerospace Medicine, Air Force Medical University, Xi’an, Shaanxi Province, China
| | - Guoqing Yang
- Aerospace Clinical Medical Center, School of Aerospace Medicine, Air Force Medical University, Xi’an, Shaanxi Province, China
| | - Lilingxuan Yao
- Third Regiment, School of Basic Medicine, Air Force Medical University, Xi’an, Shaanxi Province, China
| | - Xinyue Xu
- Aerospace Clinical Medical Center, School of Aerospace Medicine, Air Force Medical University, Xi’an, Shaanxi Province, China
| | - Yang Li
- Fourth Regiment, School of Basic Medicine, Air Force Medical University, Xi’an, Shaanxi Province, China
| | - Junhui Xue
- Aerospace Clinical Medical Center, School of Aerospace Medicine, Air Force Medical University, Xi’an, Shaanxi Province, China
- Department of Aviation Medicine, Xijing Hospital, Air Force Medical University, Xi’an, Shaanxi Province, China
| | - Zuoming Zhang
- Aerospace Clinical Medical Center, School of Aerospace Medicine, Air Force Medical University, Xi’an, Shaanxi Province, China
| | - Tao Chen
- Aerospace Clinical Medical Center, School of Aerospace Medicine, Air Force Medical University, Xi’an, Shaanxi Province, China
- Department of Aviation Medicine, Xijing Hospital, Air Force Medical University, Xi’an, Shaanxi Province, China
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Gao S, Gao S, Wang Y, Xiang L, Peng H, Chen G, Xu J, Zhang Q, Zhu C, Zhou Y, Li N, Shen X. Inhibition of Vascular Endothelial Growth Factor Reduces Photoreceptor Death in Retinal Neovascular Disease via Neurotrophic Modulation in Müller Glia. Mol Neurobiol 2025; 62:6352-6368. [PMID: 39789237 DOI: 10.1007/s12035-025-04689-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2023] [Accepted: 01/02/2025] [Indexed: 01/12/2025]
Abstract
VEGF is not only the most potent angiogenic factor, but also an important neurotrophic factor. In this study, vitreous expression of six neurotrophic factors were examined in proliferative diabetic retinopathy (PDR) patients with prior anti-VEGF therapy (n = 48) or without anti-VEGF treatment (n = 41) via ELISA. Potential source, variation and impact of these factors were further investigated in a mouse model of oxygen-induced retinopathy (OIR), as well as primary Müller cells and 661W photoreceptor cell line under hypoxic condition. Results showed that vitreous levels of NGF, NT-3, NT-4, BDNF, GDNF and CNTF were significantly higher in eyes undergoing anti-VEGF therapy compared with PDR controls. Statistical correlation between vitreous VEGF and each trophic factor was found. Hypoxia significantly induced the expressions of these neurotrophic factors, whereas application of anti-VEGF agent in OIR model could further upregulate retinal NGF, NT-3, NT-4, together with downregulation of BDNF, GDNF, CNTF, especially in Müller glia. Inhibition of Müller cell-derived VEGF would result in similar neurotrophic changes under hypoxia. With changes of corresponding neurotrophic receptors in the cocultured photoreceptor cells, their synergic effect could protect hypoxic photoreceptor from apoptosis when VEGF inhibition was present. These findings demonstrated that regulation of Müller cell-derived neurotrophic factors might be one of the possible mechanisms by which anti-VEGF therapy produced neuroprotective effects on PDR. These results provided new evidence for the therapeutic strategy of PDR.
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Affiliation(s)
- Shuang Gao
- Department of Ophthalmology, Ruijin Hospital, Affiliated Shanghai Jiaotong University School of Medicine, 197 Ruijin Er Road, Shanghai, 200025, China
| | - Sha Gao
- Department of Ophthalmology, Ruijin Hospital, Affiliated Shanghai Jiaotong University School of Medicine, 197 Ruijin Er Road, Shanghai, 200025, China
| | - Yanuo Wang
- Department of Ophthalmology, Ruijin Hospital, Affiliated Shanghai Jiaotong University School of Medicine, 197 Ruijin Er Road, Shanghai, 200025, China
| | - Lu Xiang
- Department of Ophthalmology, Ruijin Hospital, Affiliated Shanghai Jiaotong University School of Medicine, 197 Ruijin Er Road, Shanghai, 200025, China
| | - Hanwei Peng
- Department of Ophthalmology, Ruijin Hospital, Affiliated Shanghai Jiaotong University School of Medicine, 197 Ruijin Er Road, Shanghai, 200025, China
| | - Gong Chen
- Department of Ophthalmology, Ruijin Hospital, Affiliated Shanghai Jiaotong University School of Medicine, 197 Ruijin Er Road, Shanghai, 200025, China
| | - Jianmin Xu
- Department of Ophthalmology, Ruijin Hospital, Affiliated Shanghai Jiaotong University School of Medicine, 197 Ruijin Er Road, Shanghai, 200025, China
| | - Qiong Zhang
- Department of Ophthalmology, Ruijin Hospital, Affiliated Shanghai Jiaotong University School of Medicine, 197 Ruijin Er Road, Shanghai, 200025, China
| | - Caihong Zhu
- Department of Ophthalmology, Ruijin Hospital, Affiliated Shanghai Jiaotong University School of Medicine, 197 Ruijin Er Road, Shanghai, 200025, China
| | - Yingming Zhou
- Department of Ophthalmology, Ruijin Hospital, Affiliated Shanghai Jiaotong University School of Medicine, 197 Ruijin Er Road, Shanghai, 200025, China
| | - Na Li
- Department of Ophthalmology, Ruijin Hospital, Affiliated Shanghai Jiaotong University School of Medicine, 197 Ruijin Er Road, Shanghai, 200025, China.
| | - Xi Shen
- Department of Ophthalmology, Ruijin Hospital, Affiliated Shanghai Jiaotong University School of Medicine, 197 Ruijin Er Road, Shanghai, 200025, China.
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Arrigo A, Cremona O, Aragona E, Casoni F, Consalez G, Dogru RM, Hauck SM, Antropoli A, Bianco L, Parodi MB, Bandello F, Grosche A. Müller cells trophism and pathology as the next therapeutic targets for retinal diseases. Prog Retin Eye Res 2025; 106:101357. [PMID: 40254246 DOI: 10.1016/j.preteyeres.2025.101357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2025] [Revised: 04/14/2025] [Accepted: 04/15/2025] [Indexed: 04/22/2025]
Abstract
Müller cells are a crucial retinal cell type involved in multiple regulatory processes and functions that are essential for retinal health and functionality. Acting as structural and functional support for retinal neurons and photoreceptors, Müller cells produce growth factors, regulate ion and fluid homeostasis, and facilitate neuronal signaling. They play a pivotal role in retinal morphogenesis and cell differentiation, significantly contributing to macular development. Due to their radial morphology and unique cytoskeletal organization, Müller cells act as optical fibers, efficiently channeling photons directly to the photoreceptors. In response to retinal damage, Müller cells undergo specific gene expression and functional changes that serve as a first line of defense for neurons, but can also lead to unwarranted cell dysfunction, contributing to cell death and neurodegeneration. In some species, Müller cells can reactivate their developmental program, promoting retinal regeneration and plasticity-a remarkable ability that holds promising therapeutic potential if harnessed in mammals. The crucial and multifaceted roles of Müller cells-that we propose to collectively call "Müller cells trophism"-highlight the necessity of maintaining their functionality. Dysfunction of Müller cells, termed "Müller cells pathology," has been associated with a plethora of retinal diseases, including age-related macular degeneration, diabetic retinopathy, vitreomacular disorders, macular telangiectasia, and inherited retinal dystrophies. In this review, we outline how even subtle disruptions in Müller cells trophism can drive the pathological cascade of Müller cells pathology, emphasizing the need for targeted therapies to preserve retinal health and prevent disease progression.
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Affiliation(s)
- Alessandro Arrigo
- Ophthalmology Unit, IRCCS San Raffaele Scientific Institute, Milan, Italy; Eye Repair Unit, Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Milan, Italy.
| | - Ottavio Cremona
- Vita-Salute San Raffaele University, Milan, Italy; Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Milan, Italy.
| | - Emanuela Aragona
- Ophthalmology Unit, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Filippo Casoni
- Vita-Salute San Raffaele University, Milan, Italy; Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Giacomo Consalez
- Vita-Salute San Raffaele University, Milan, Italy; Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Rüya Merve Dogru
- Department of Physiological Genomics, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
| | - Stefanie M Hauck
- Metabolomics and Proteomics Core, Helmholtz Zentrum München, German Research Center for Environmental Health, Munich, 80939, Germany
| | - Alessio Antropoli
- Ophthalmology Unit, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Lorenzo Bianco
- Ophthalmology Unit, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | | | - Francesco Bandello
- Ophthalmology Unit, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Antje Grosche
- Department of Physiological Genomics, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany.
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Taylor O, Kelly L, El-Hodiri H, Fischer AJ. Sphingosine-1-phosphate signaling through Müller glia regulates neuroprotection and the accumulation of immune cells in the rodent retina. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2025:2025.02.03.636254. [PMID: 39975061 PMCID: PMC11838470 DOI: 10.1101/2025.02.03.636254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 02/21/2025]
Abstract
The purpose of this study was to investigate how Sphingosine-1-phosphate (S1P) signaling regulates glial phenotype, neuroprotection, and reprogramming of Müller glia (MG) into neurogenic MG-derived progenitor cells (MGPCs) in the adult mouse retina. We found that S1P-related genes were dynamically regulated following retinal damage. S1pr1 (encoding S1P receptor 1) and Sphk1 (encoding sphingosine kinase 1) are expressed at low levels by resting MG and are rapidly upregulated following acute damage. Overexpression of the neurogenic bHLH transcription factor Ascl1 in MG downregulates S1pr1, and inhibition of Sphk1 and S1pr1/3 enhances Ascl1-driven differentiation of bipolar-like cells and suppresses glial differentiation. Treatments that activate S1pr1 or increase retinal levels of S1P initiate pro-inflammatory NFκB-signaling in MG, whereas treatments that inhibit S1pr1 or decreased levels of S1P suppress NFκB-signaling in MG in damaged retinas. Conditional knock-out of NFκB-signaling in MG increases glial expression of S1pr1 but decreases levels of S1pr3 and Sphk1. Conditional knock-out (cKO) of S1pr1 in MG, but not Sphk1, enhances the accumulation of immune cells in acutely damaged retinas. cKO of S1pr1 is neuroprotective to ganglion cells, whereas cKO of Sphk1 is neuroprotective to amacrine cells in NMDA-damaged retinas. Consistent with these findings, pharmacological treatments that inhibit S1P receptors or inhibit Sphk1 had protective effects upon inner retinal neurons. We conclude that the S1P-signaling pathway is activated in MG after damage and this pathway acts secondarily to restrict the accumulation of immune cells, impairs neuron survival and suppresses the reprogramming of MG into neurogenic progenitors in the adult mouse retina.
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Affiliation(s)
- Olivia Taylor
- Department of Neuroscience, College of Medicine, The Ohio State University, Columbus, OH 43210, USA
- Neuroscience Graduate Program, The Ohio State University, Columbus, OH 43210, USA
| | - Lisa Kelly
- Department of Neuroscience, College of Medicine, The Ohio State University, Columbus, OH 43210, USA
| | - Heithem El-Hodiri
- Department of Neuroscience, College of Medicine, The Ohio State University, Columbus, OH 43210, USA
| | - Andy J. Fischer
- Department of Neuroscience, College of Medicine, The Ohio State University, Columbus, OH 43210, USA
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Lin CH, Wu MR, Tanasa B, Prakhar P, Deng B, Davis AE, Li L, Xia A, Shan Y, Fort PE, Wang S. Induction of a Müller Glial Cell-Specific Protective Pathway Safeguards the Retina From Diabetes-Induced Damage. Diabetes 2025; 74:96-107. [PMID: 39446557 DOI: 10.2337/db24-0199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/10/2024] [Accepted: 10/19/2024] [Indexed: 10/26/2024]
Abstract
Diabetes can lead to cell type-specific responses in the retina, including vascular lesions, glial dysfunction, and neurodegeneration, all of which contribute to retinopathy. However, the molecular mechanisms underlying these cell type-specific responses, and the cell types that are sensitive to diabetes have not been fully elucidated. Using single-cell transcriptomics, we profiled the transcriptional changes induced by diabetes in different retinal cell types in rat models as the disease progressed. Rod photoreceptors, a subtype of amacrine interneurons, and Müller glial cells (MGs) exhibited rapid responses to diabetes at the transcript levels. Genes associated with ion regulation were upregulated in all three cell types, suggesting a common response to diabetes. Furthermore, focused studies revealed that although MG initially increased the expression of genes playing protective roles, they cannot sustain this beneficial effect. We explored one of the candidate protective genes, Zinc finger protein 36 homolog (Zfp36), and observed that depleting Zfp36 in rat MGs in vivo using adeno-associated virus-based tools exacerbated diabetes-induced phenotypes, including glial reactivation, neurodegeneration, and vascular defects. Overexpression of Zfp36 slowed the development of these phenotypes. This work unveiled retinal cell types that are sensitive to diabetes and demonstrated that MGs can mount protective responses through Zfp36. ARTICLE HIGHLIGHTS
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Affiliation(s)
- Cheng-Hui Lin
- Department of Ophthalmology, Mary M. and Sash A. Spencer Center for Vision Research, Byers Eye Institute, Stanford University, Stanford, CA
| | - Man-Ru Wu
- Department of Ophthalmology, Mary M. and Sash A. Spencer Center for Vision Research, Byers Eye Institute, Stanford University, Stanford, CA
| | - Bogdan Tanasa
- Department of Ophthalmology, Mary M. and Sash A. Spencer Center for Vision Research, Byers Eye Institute, Stanford University, Stanford, CA
| | - Praveen Prakhar
- Department of Ophthalmology, Mary M. and Sash A. Spencer Center for Vision Research, Byers Eye Institute, Stanford University, Stanford, CA
| | - Boxiong Deng
- Department of Ophthalmology, Mary M. and Sash A. Spencer Center for Vision Research, Byers Eye Institute, Stanford University, Stanford, CA
| | - Alexander E Davis
- Department of Ophthalmology, Mary M. and Sash A. Spencer Center for Vision Research, Byers Eye Institute, Stanford University, Stanford, CA
| | - Liang Li
- Department of Ophthalmology, Mary M. and Sash A. Spencer Center for Vision Research, Byers Eye Institute, Stanford University, Stanford, CA
| | - Alexander Xia
- Department of Ophthalmology, Mary M. and Sash A. Spencer Center for Vision Research, Byers Eye Institute, Stanford University, Stanford, CA
| | - Yang Shan
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI
| | - Patrice E Fort
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI
| | - Sui Wang
- Department of Ophthalmology, Mary M. and Sash A. Spencer Center for Vision Research, Byers Eye Institute, Stanford University, Stanford, CA
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Le YZ. Brain-Derived Neurotrophic Factor in Retinal Integrity Under Diabetic and Hypoxic Conditions. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2025; 1468:293-296. [PMID: 39930211 DOI: 10.1007/978-3-031-76550-6_48] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2025]
Abstract
We are interested in the mechanism and therapeutic strategy for the alteration of retinal neuronal integrity in diabetic retinopathy (DR) and other hypoxic retinal diseases. In this article, we will discuss our work in exploring the relationship between vascular endothelial growth factor (VEGF) and brain-derived neurotrophic factor (BDNF) in the maintenance of major retinal supporting cells, Müller cell (MC), and in investigating the potential role and mechanisms of BDNF-mediated MC viability through its signaling cascade under diabetic and hypoxic conditions. While our data suggest that BDNF is a positive regulator of MC viability through the classical survival and proliferation pathways under diabetic/hypoxic conditions, the biological significance of BDNF-mediated MC viability in diabetes/hypoxia remains unclear, which is a major challenge in designing BDNF-mediated neuroprotective strategy for DR and hypoxic retinal disorders.
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Affiliation(s)
- Yun-Zheng Le
- Departments of Medicine/Endocrinology, Cell Biology, and Ophthalmology, Harold Hamm Diabetes Center, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.
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Medina-Arellano AE, Albert-Garay JS, Medina-Sánchez T, Fonseca KH, Ruiz-Cruz M, Ochoa-de la Paz L. Müller cells and retinal angiogenesis: critical regulators in health and disease. Front Cell Neurosci 2024; 18:1513686. [PMID: 39720707 PMCID: PMC11666533 DOI: 10.3389/fncel.2024.1513686] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2024] [Accepted: 11/27/2024] [Indexed: 12/26/2024] Open
Abstract
Müller cells are the most abundant glial cells in the mammalian retina. Their morphology and metabolism enable them to be in close contact and interact biochemically and physically with almost all retinal cell types, including neurons, pericytes, endothelial cells, and other glial cells, influencing their physiology by releasing bioactive molecules. Studies indicate that Müller glial cells are the primary source of angiogenic growth factor secretion in the neuroretina. Because of this, over the past decade, it has been postulated that Müller glial cells play a significant role in maintaining retinal vascular homeostasis, with potential implications in vasoproliferative retinopathies. This review aims to summarize the current understanding of the mechanisms by which Müller glial cells influence retinal angiogenesis in health and disease, with a particular emphasis on three of the retinopathies with the most significant impact on visual health worldwide: diabetic retinopathy, retinopathy of prematurity, and age-related macular degeneration.
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Affiliation(s)
- Alan E. Medina-Arellano
- Laboratorio de Neurobiología Molecular y Celular de la Glía, Facultad de Medicina, Departamento de Bioquímica, UNAM, Mexico City, Mexico
- Unidad de Investigación APEC-UNAM, Asociación para Evitar la Ceguera en México I.A.P., Mexico City, Mexico
- Programa de Doctorado en Ciencias Biomédicas, UNAM, Mexico City, Mexico
| | - Jesús Silvestre Albert-Garay
- Laboratorio de Neurobiología Molecular y Celular de la Glía, Facultad de Medicina, Departamento de Bioquímica, UNAM, Mexico City, Mexico
- Unidad de Investigación APEC-UNAM, Asociación para Evitar la Ceguera en México I.A.P., Mexico City, Mexico
| | - Tania Medina-Sánchez
- Laboratorio de Neuroquímica, Subdirección de Investigaciones Clínicas, Instituto Nacional de Psiquiatría “Ramón de la Fuente Muñiz”, Mexico City, Mexico
| | - Karla Hernández Fonseca
- Laboratorio de Neuroquímica, Subdirección de Investigaciones Clínicas, Instituto Nacional de Psiquiatría “Ramón de la Fuente Muñiz”, Mexico City, Mexico
| | - Matilde Ruiz-Cruz
- Unidad de Investigación APEC-UNAM, Asociación para Evitar la Ceguera en México I.A.P., Mexico City, Mexico
| | - Lenin Ochoa-de la Paz
- Laboratorio de Neurobiología Molecular y Celular de la Glía, Facultad de Medicina, Departamento de Bioquímica, UNAM, Mexico City, Mexico
- Unidad de Investigación APEC-UNAM, Asociación para Evitar la Ceguera en México I.A.P., Mexico City, Mexico
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Peña JS, Berthiaume F, Vazquez M. Müller Glia Co-Regulate Barrier Permeability with Endothelial Cells in an Vitro Model of Hyperglycemia. Int J Mol Sci 2024; 25:12271. [PMID: 39596335 PMCID: PMC11595118 DOI: 10.3390/ijms252212271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2024] [Revised: 11/08/2024] [Accepted: 11/12/2024] [Indexed: 11/28/2024] Open
Abstract
Diabetic retinopathy is a complex, microvascular disease that impacts millions of working adults each year. High blood glucose levels from Diabetes Mellitus lead to the accumulation of advanced glycation end-products (AGEs), which promote inflammation and the breakdown of the inner blood retinal barrier (iBRB), resulting in vision loss. This study used an in vitro model of hyperglycemia to examine how endothelial cells (ECs) and Müller glia (MG) collectively regulate molecular transport. Changes in cell morphology, the expression of junctional proteins, and the reactive oxygen species (ROS) of ECs and MG were examined when exposed to a hyperglycemic medium containing AGEs. Trans-endothelial resistance (TEER) assays were used to measure the changes in cell barrier resistance in response to hyperglycemic and inflammatory conditions, with and without an anti-VEGF compound. Both of the cell types responded to hyperglycemic conditions with significant changes in the cell area and morphology, the ROS, and the expression of the junctional proteins ZO-1, CX-43, and CD40, as well as the receptor for AGEs. The resistivities of the individual and dual ECs and MG barriers decreased within the hyperglycemia model but were restored to that of basal, normoglycemic levels when treated with anti-VEGF. This study illustrated significant phenotypic responses to an in vitro model of hyperglycemia, as well as significant changes in the expression of the key proteins used for cell-cell communication. The results highlight important, synergistic relationships between the ECs and MG and how they contribute to changes in barrier function in combination with conventional treatments.
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Affiliation(s)
| | | | - Maribel Vazquez
- Department of Biomedical Engineering, Rutgers, The State University of New Jersey, 599 Taylor Road, Piscataway, NJ 08854, USA; (J.S.P.); (F.B.)
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Rajala RVS, Rajala A. From Insight to Eyesight: Unveiling the Secrets of the Insulin-Like Growth Factor Axis in Retinal Health. Aging Dis 2024; 15:1994-2002. [PMID: 38300646 PMCID: PMC11346401 DOI: 10.14336/ad.2024.0128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2024] [Accepted: 01/29/2024] [Indexed: 02/02/2024] Open
Abstract
Insulin-like growth factor-1 (IGF-1) plays a diverse role in the retina, exerting its effects in both normal and diseased conditions. Deficiency of IGF-1 in humans leads to issues such as microcephaly, mental retardation, deafness, and postnatal growth failure. IGF-1 is produced in the retinal pigment epithelium (RPE) and activates the IGF-1 receptor (IGF-1R) in photoreceptor cells. When IGF-1R is absent in rod cells, it results in the degeneration of photoreceptors, emphasizing the neuroprotective function of IGF signaling in these cells. Contrastingly, in neovascular age-related macular degeneration (AMD), there is an overexpression of both IGF-1 and IGF-1R in RPE. The mechanisms behind this altered regulation of IGF-1 in diseased states are currently unknown. This comprehensive review provides recent insights into the role of IGF-1 in the health and disease of the retina, raising several unanswered questions that still need further investigation.
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Affiliation(s)
- Raju V S Rajala
- Departments of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma, USA
- Physiology, University of Oklahoma Health Sciences Center, Oklahoma, USA
- Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma, USA
- Dean McGee Eye Institute, Oklahoma, Oklahoma, USA
| | - Ammaji Rajala
- Departments of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma, USA
- Dean McGee Eye Institute, Oklahoma, Oklahoma, USA
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Li N, Gao S, Gao S, Wang Y, Huang H, Wang J, Shen X. Knockdown of thioredoxin interacting protein in Müller cells attenuates photoreceptor apoptosis in streptozotocin-induced diabetic mouse model. Int J Biol Macromol 2024; 271:132731. [PMID: 38815945 DOI: 10.1016/j.ijbiomac.2024.132731] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2024] [Revised: 04/28/2024] [Accepted: 05/16/2024] [Indexed: 06/01/2024]
Abstract
We explored the effect of inhibition of thioredoxin interacting protein (Txnip) on neuroprotection in Müller cells under high glucose. Wild-type (WT) and Txnip knockout (Txnip-/-) mice were used to establish a streptozotocin (STZ)-induced diabetes model and a Müller cells high glucose model. We detected BDNF expression and PI3K/AKT/CREB pathway activation levels in the retina and Müller cells of each group in vivo and in vitro experiments. The Txnip-/- STZ group showed higher expression of BDNF and phosphorylation of PI3K/AKT/CREB in retina, and less retinal photoreceptor apoptosis was observed in Txnip-/- diabetic group than in WT. After using an inhibitor of PI3K signaling pathway, BDNF expression was reduced; In vitro co-cultured with Müller cells in different groups, 661 W cells showed different situations, Txnip-/- Müller cells maximum downregulated Cleaved-caspase 3 expression in 661 W, accompanied by an increase in Bcl-2/Bax ratio. These findings indicate that inhibiting endogenous Txnip in mouse Müller cells can promote their expression and secretion of BDNF, thereby reducing HG induced photoreceptor apoptosis and having important neuroprotective effects on DR. The regulation of BDNF expression by Txnip may be achieved by activating the PI3K/AKT/CREB pathway. This study suggests that regulating Txnip may be a potential target for DR treatment.
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Affiliation(s)
- Na Li
- Department of Ophthalmology, Ruijin Hospital, Affiliated Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Shuang Gao
- Department of Ophthalmology, Ruijin Hospital, Affiliated Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Sha Gao
- Department of Ophthalmology, Ruijin Hospital, Affiliated Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Yanuo Wang
- Department of Ophthalmology, Ruijin Hospital, Affiliated Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Hanwen Huang
- Department of Ophthalmology, Ruijin Hospital, Affiliated Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Jing Wang
- Department of Ophthalmology, Ruijin Hospital, Affiliated Shanghai Jiaotong University School of Medicine, Shanghai, China.
| | - Xi Shen
- Department of Ophthalmology, Ruijin Hospital, Affiliated Shanghai Jiaotong University School of Medicine, Shanghai, China.
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Gao S, Li N, Lin Z, Zhong Y, Wang Y, Shen X. Inhibition of NLRP3 inflammasome by MCC950 under hypoxia alleviates photoreceptor apoptosis via inducing autophagy in Müller glia. FASEB J 2024; 38:e23671. [PMID: 38752538 DOI: 10.1096/fj.202301922rr] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Revised: 04/06/2024] [Accepted: 05/02/2024] [Indexed: 07/16/2024]
Abstract
NLRP3 inflammasome activation has emerged as a critical initiator of inflammatory response in ischemic retinopathy. Here, we identified the effect of a potent, selective NLRP3 inhibitor, MCC950, on autophagy and apoptosis under hypoxia. Neonatal mice were exposed to hyperoxia for 5 days to establish oxygen-induced retinopathy (OIR) model. Intravitreal injection of MCC950 was given, and then autophagy and apoptosis markers were assessed. Retinal autophagy, apoptosis, and related pathways were evaluated by western blot, immunofluorescent labeling, transmission electron microscopy, and TUNEL assay. Autophagic activity in Müller glia after NLRP3 inflammasome inhibition, together with its influence on photoreceptor death, was studied using western blot, immunofluorescence staining, mRFP-GFP-LC3 adenovirus transfection, cell viability, proliferation, and apoptosis assays. Results showed that activation of NLRP3 inflammasome in Müller glia was detected in OIR model. MCC950 could improve impaired retinal autophagic flux and attenuate retinal apoptosis while it regulated the retinal AMPK/mTOR/ULK-1 pathway. Suppressed autophagy and depressed proliferation capacity resulting from hypoxia was promoted after MCC950 treatment in Müller glia. Inhibition of AMPK and ULK-1 pathway significantly interfered with the MCC950-induced autophagy activity, indicating MCC950 positively modulated autophagy through AMPK/mTOR/ULK-1 pathway in Müller cells. Furthermore, blockage of autophagy in Müller glia significantly induced apoptosis in the cocultured 661W photoreceptor cells, whereas MCC950 markedly preserved the density of photoreceptor cells. These findings substantiated the therapeutic potential of MCC950 against impaired autophagy and subsequent apoptosis under hypoxia. Such protective effect might involve the modulation of AMPK/mTOR/ULK-1 pathway. Targeting NLRP3 inflammasome in Müller glia could be beneficial for photoreceptor survival under hypoxic conditions.
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Affiliation(s)
- Shuang Gao
- Department of Ophthalmology, Ruijin Hospital, Affiliated Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Na Li
- Department of Ophthalmology, Ruijin Hospital, Affiliated Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Zhongjing Lin
- Department of Ophthalmology, Renji Hospital, Affiliated Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Yisheng Zhong
- Department of Ophthalmology, Ruijin Hospital, Affiliated Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Yanuo Wang
- Department of Ophthalmology, Ruijin Hospital, Affiliated Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Xi Shen
- Department of Ophthalmology, Ruijin Hospital, Affiliated Shanghai Jiaotong University School of Medicine, Shanghai, China
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Zhu T, Li Y, Zhu L, Xu J, Feng Z, Chen H, Shi S, Liu C, Ou Q, Gao F, Zhang J, Jin C, Xu J, Li J, Zhang J, Bi Y, Xu GT, Wang J, Tian H, Lu L. GMFB/AKT/TGF-β3 in Müller cells mediated early retinal degeneration in a streptozotocin-induced rat diabetes model. Glia 2024; 72:504-528. [PMID: 37904673 DOI: 10.1002/glia.24486] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Revised: 09/14/2023] [Accepted: 10/16/2023] [Indexed: 11/01/2023]
Abstract
Retinal degeneration, characterized by Müller cell gliosis and photoreceptor apoptosis, is considered an early event in diabetic retinopathy (DR). Our previous study proposed that GMFB may mediate diabetic retinal degeneration. This study identified GMFB as a sensitive and functional gliosis marker for DR. Compared to the wild type (WT) group, Gmfb knockout (KO) significantly improved visual function, attenuated gliosis, reduced the apoptosis of neurons, and decreased the mRNA levels of tumor necrosis factor α (Tnf-α) and interleukin-1β (Il-1β) in diabetic retinas. Tgf-β3 was enriched by hub genes using RNA sequencing in primary WT and KO Müller cells. Gmfb KO significantly upregulated the transforming growth factor (TGF)-β3 protein level via the AKT pathway. The protective effect of TGF-β3 in the vitreous resulted in significantly improved visual function and decreased the number of apoptotic cells in the diabetic retina. The protection of Gmfb KO in primary Müller cells against high glucose (HG)-induced photoreceptor apoptosis was partially counteracted by TGF-β3 antibody and administration of TGFBR1/2 inhibitors. Nuclear receptor subfamily 3 group C member 1 (NR3C1) binds to the promoter region of Gmfb and regulates Gmfb mRNA at the transcriptional level. NR3C1 was increased in the retinas of early diabetic rats but decreased in the retinas of late diabetic rats. N'-[(1E)-(3-Methoxyphenyl)Methylene]-3-Methyl-1H-Pyrazole-5-Carbohydrazide (DS-5) was identified as an inhibitor of GMFB, having a protective role in DR. We demonstrated that GMFB/AKT/TGF-β3 mediated early diabetic retinal degeneration in diabetic rats. This study provides a novel therapeutic strategy for treating retinal degeneration in patients with DR.
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Affiliation(s)
- Tong Zhu
- Department of Ophthalmology of Shanghai Tongji Hospital, Laboratory of Clinical Visual Science of Tongji Eye Institute, School of Medicine, Tongji University, Shanghai, China
- Department of Biochemistry and Molecular Biology, Tongji University School of Medicine, Shanghai, China
| | - Yingao Li
- Department of Ophthalmology of Shanghai Tongji Hospital, Laboratory of Clinical Visual Science of Tongji Eye Institute, School of Medicine, Tongji University, Shanghai, China
- Department of Biochemistry and Molecular Biology, Tongji University School of Medicine, Shanghai, China
| | - Lilin Zhu
- Department of Ophthalmology of Shanghai Tongji Hospital, Laboratory of Clinical Visual Science of Tongji Eye Institute, School of Medicine, Tongji University, Shanghai, China
- Department of Biochemistry and Molecular Biology, Tongji University School of Medicine, Shanghai, China
| | - Jinyuan Xu
- Department of Ophthalmology of Shanghai Tongji Hospital, Laboratory of Clinical Visual Science of Tongji Eye Institute, School of Medicine, Tongji University, Shanghai, China
- Department of Biochemistry and Molecular Biology, Tongji University School of Medicine, Shanghai, China
| | - Zijun Feng
- Department of Biochemistry and Molecular Biology, Tongji University School of Medicine, Shanghai, China
| | - Hao Chen
- Department of Ophthalmology of Shanghai Tenth People's Hospital, Tongji University, Shanghai, China
| | - Si Shi
- Department of Ophthalmology of Shanghai Tongji Hospital, Laboratory of Clinical Visual Science of Tongji Eye Institute, School of Medicine, Tongji University, Shanghai, China
- Department of Biochemistry and Molecular Biology, Tongji University School of Medicine, Shanghai, China
| | - Caiying Liu
- Department of Ophthalmology of Shanghai Tongji Hospital, Laboratory of Clinical Visual Science of Tongji Eye Institute, School of Medicine, Tongji University, Shanghai, China
- Department of Biochemistry and Molecular Biology, Tongji University School of Medicine, Shanghai, China
| | - Qingjian Ou
- Department of Ophthalmology of Shanghai Tongji Hospital, Laboratory of Clinical Visual Science of Tongji Eye Institute, School of Medicine, Tongji University, Shanghai, China
- Department of Pharmacology, Tongji University School of Medicine, Shanghai, China
| | - Furong Gao
- Department of Ophthalmology of Shanghai Tongji Hospital, Laboratory of Clinical Visual Science of Tongji Eye Institute, School of Medicine, Tongji University, Shanghai, China
- Department of Biochemistry and Molecular Biology, Tongji University School of Medicine, Shanghai, China
| | - Jieping Zhang
- Department of Ophthalmology of Shanghai Tongji Hospital, Laboratory of Clinical Visual Science of Tongji Eye Institute, School of Medicine, Tongji University, Shanghai, China
- Department of Pharmacology, Tongji University School of Medicine, Shanghai, China
| | - Caixia Jin
- Department of Ophthalmology of Shanghai Tongji Hospital, Laboratory of Clinical Visual Science of Tongji Eye Institute, School of Medicine, Tongji University, Shanghai, China
- Department of Biochemistry and Molecular Biology, Tongji University School of Medicine, Shanghai, China
| | - Jingying Xu
- Department of Ophthalmology of Shanghai Tongji Hospital, Laboratory of Clinical Visual Science of Tongji Eye Institute, School of Medicine, Tongji University, Shanghai, China
- Department of Biochemistry and Molecular Biology, Tongji University School of Medicine, Shanghai, China
| | - Jiao Li
- Department of Biochemistry and Molecular Biology, Tongji University School of Medicine, Shanghai, China
| | - Jingfa Zhang
- Department of Ophthalmology of Shanghai First People's Hospital, Shanghai Jiaotong University, Shanghai, China
| | - Yanlong Bi
- Department of Ophthalmology of Shanghai Tongji Hospital, Laboratory of Clinical Visual Science of Tongji Eye Institute, School of Medicine, Tongji University, Shanghai, China
| | - Guo-Tong Xu
- Department of Ophthalmology of Shanghai Tongji Hospital, Laboratory of Clinical Visual Science of Tongji Eye Institute, School of Medicine, Tongji University, Shanghai, China
- Department of Pharmacology, Tongji University School of Medicine, Shanghai, China
| | - Juan Wang
- Department of Ophthalmology of Shanghai Tongji Hospital, Laboratory of Clinical Visual Science of Tongji Eye Institute, School of Medicine, Tongji University, Shanghai, China
- Department of Human Genetics, Tongji University School of Medicine, Shanghai, China
| | - Haibin Tian
- Department of Ophthalmology of Shanghai Tongji Hospital, Laboratory of Clinical Visual Science of Tongji Eye Institute, School of Medicine, Tongji University, Shanghai, China
- Department of Biochemistry and Molecular Biology, Tongji University School of Medicine, Shanghai, China
| | - Lixia Lu
- Department of Ophthalmology of Shanghai Tongji Hospital, Laboratory of Clinical Visual Science of Tongji Eye Institute, School of Medicine, Tongji University, Shanghai, China
- Department of Biochemistry and Molecular Biology, Tongji University School of Medicine, Shanghai, China
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13
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Navneet S, Wilson K, Rohrer B. Müller Glial Cells in the Macula: Their Activation and Cell-Cell Interactions in Age-Related Macular Degeneration. Invest Ophthalmol Vis Sci 2024; 65:42. [PMID: 38416457 PMCID: PMC10910558 DOI: 10.1167/iovs.65.2.42] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Accepted: 02/10/2024] [Indexed: 02/29/2024] Open
Abstract
Müller glia, the main glial cell of the retina, are critical for neuronal and vascular homeostasis in the retina. During age-related macular degeneration (AMD) pathogenesis, Müller glial activation, remodeling, and migrations are reported in the areas of retinal pigment epithelial (RPE) degeneration, photoreceptor loss, and choroidal neovascularization (CNV) lesions. Despite this evidence indicating glial activation localized to the regions of AMD pathogenesis, it is unclear whether these glial responses contribute to AMD pathology or occur merely as a bystander effect. In this review, we summarize how Müller glia are affected in AMD retinas and share a prospect on how Müller glial stress might directly contribute to the pathogenesis of AMD. The goal of this review is to highlight the need for future studies investigating the Müller cell's role in AMD. This may lead to a better understanding of AMD pathology, including the conversion from dry to wet AMD, which has no effective therapy currently and may shed light on drug intolerance and resistance to current treatments.
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Affiliation(s)
- Soumya Navneet
- Department of Ophthalmology, Medical University of South Carolina, Charleston, South Carolina, United States
| | - Kyrie Wilson
- Department of Ophthalmology, Medical University of South Carolina, Charleston, South Carolina, United States
| | - Bärbel Rohrer
- Department of Ophthalmology, Medical University of South Carolina, Charleston, South Carolina, United States
- Department of Neuroscience, Medical University of South Carolina, Charleston, South Carolina, United States
- Ralph H. Johnson VA Medical Center, Division of Research, Charleston, South Carolina, United States
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14
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Sun WJ, An XD, Zhang YH, Zhao XF, Sun YT, Yang CQ, Kang XM, Jiang LL, Ji HY, Lian FM. The ideal treatment timing for diabetic retinopathy: the molecular pathological mechanisms underlying early-stage diabetic retinopathy are a matter of concern. Front Endocrinol (Lausanne) 2023; 14:1270145. [PMID: 38027131 PMCID: PMC10680169 DOI: 10.3389/fendo.2023.1270145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Accepted: 10/23/2023] [Indexed: 12/01/2023] Open
Abstract
Diabetic retinopathy (DR) is a prevalent complication of diabetes, significantly impacting patients' quality of life due to vision loss. No pharmacological therapies are currently approved for DR, excepted the drugs to treat diabetic macular edema such as the anti-VEGF agents or steroids administered by intraocular route. Advancements in research have highlighted the crucial role of early intervention in DR for halting or delaying disease progression. This holds immense significance in enhancing patients' quality of life and alleviating the societal burden associated with medical care costs. The non-proliferative stage represents the early phase of DR. In comparison to the proliferative stage, pathological changes primarily manifest as microangiomas and hemorrhages, while at the cellular level, there is a loss of pericytes, neuronal cell death, and disruption of components and functionality within the retinal neuronal vascular unit encompassing pericytes and neurons. Both neurodegenerative and microvascular abnormalities manifest in the early stages of DR. Therefore, our focus lies on the non-proliferative stage of DR and we have initially summarized the mechanisms involved in its development, including pathways such as polyols, that revolve around the pathological changes occurring during this early stage. We also integrate cutting-edge mechanisms, including leukocyte adhesion, neutrophil extracellular traps, multiple RNA regulation, microorganisms, cell death (ferroptosis and pyroptosis), and other related mechanisms. The current status of drug therapy for early-stage DR is also discussed to provide insights for the development of pharmaceutical interventions targeting the early treatment of DR.
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Affiliation(s)
- Wen-Jie Sun
- Guang’anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, China
- China Academy of Chinese Medical Sciences, Beijing, China
| | - Xue-Dong An
- Guang’anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, China
- China Academy of Chinese Medical Sciences, Beijing, China
| | - Yue-Hong Zhang
- Guang’anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, China
- China Academy of Chinese Medical Sciences, Beijing, China
| | - Xue-Fei Zhao
- Guang’anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, China
- China Academy of Chinese Medical Sciences, Beijing, China
| | - Yu-Ting Sun
- Guang’anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, China
- China Academy of Chinese Medical Sciences, Beijing, China
| | - Cun-Qing Yang
- Guang’anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, China
- China Academy of Chinese Medical Sciences, Beijing, China
| | - Xiao-Min Kang
- Guang’anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, China
- Beijing University of Chinese Medicine, Beijing, China
| | - Lin-Lin Jiang
- Guang’anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, China
- Beijing University of Chinese Medicine, Beijing, China
| | - Hang-Yu Ji
- Guang’anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Feng-Mei Lian
- Guang’anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, China
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15
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Augustine J, Pavlou S, Harkin K, Stitt AW, Xu H, Chen M. IL-33 regulates Müller cell-mediated retinal inflammation and neurodegeneration in diabetic retinopathy. Dis Model Mech 2023; 16:dmm050174. [PMID: 37671525 PMCID: PMC10499035 DOI: 10.1242/dmm.050174] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Accepted: 07/31/2023] [Indexed: 09/07/2023] Open
Abstract
Diabetic retinopathy (DR) is characterised by dysfunction of the retinal neurovascular unit, leading to visual impairment and blindness. Müller cells are key components of the retinal neurovascular unit and diabetes has a detrimental impact on these glial cells, triggering progressive neurovascular pathology of DR. Amongst many factors expressed by Müller cells, interleukin-33 (IL-33) has an established immunomodulatory role, and we investigated the role of endogenous IL-33 in DR. The expression of IL-33 in Müller cells increased during diabetes. Wild-type and Il33-/- mice developed equivalent levels of hyperglycaemia and weight loss following streptozotocin-induced diabetes. Electroretinogram a- and b-wave amplitudes, neuroretina thickness, and the numbers of cone photoreceptors and ganglion cells were significantly reduced in Il33-/- diabetic mice compared with those in wild-type counterparts. The Il33-/- diabetic retina also exhibited microglial activation, sustained gliosis, and upregulation of pro-inflammatory cytokines and neurotrophins. Primary Müller cells from Il33-/- mice expressed significantly lower levels of neurotransmitter-related genes (Glul and Slc1a3) and neurotrophin genes (Cntf, Lif, Igf1 and Ngf) under high-glucose conditions. Our results suggest that deletion of IL-33 promotes inflammation and neurodegeneration in DR, and that this cytokine is critical for regulation of glutamate metabolism, neurotransmitter recycling and neurotrophin secretion by Müller cells.
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Affiliation(s)
- Josy Augustine
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, Belfast BT9 7BL, Northern Ireland, UK
| | - Sofia Pavlou
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, Belfast BT9 7BL, Northern Ireland, UK
| | - Kevin Harkin
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, Belfast BT9 7BL, Northern Ireland, UK
| | - Alan W. Stitt
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, Belfast BT9 7BL, Northern Ireland, UK
| | - Heping Xu
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, Belfast BT9 7BL, Northern Ireland, UK
| | - Mei Chen
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, Belfast BT9 7BL, Northern Ireland, UK
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16
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Donato L, Scimone C, Alibrandi S, Scalinci SZ, Mordà D, Rinaldi C, D'Angelo R, Sidoti A. Human retinal secretome: A cross-link between mesenchymal and retinal cells. World J Stem Cells 2023; 15:665-686. [PMID: 37545752 PMCID: PMC10401416 DOI: 10.4252/wjsc.v15.i7.665] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 03/17/2023] [Accepted: 04/10/2023] [Indexed: 07/25/2023] Open
Abstract
In recent years, mesenchymal stem cells (MSC) have been considered the most effective source for regenerative medicine, especially due to released soluble paracrine bioactive components and extracellular vesicles. These factors, collectively called the secretome, play crucial roles in immunomodulation and in improving survival and regeneration capabilities of injured tissue. Recently, there has been a growing interest in the secretome released by retinal cytotypes, especially retinal pigment epithelium and Müller glia cells. The latter trophic factors represent the key to preserving morphofunctional integrity of the retina, regulating biological pathways involved in survival, function and responding to injury. Furthermore, these factors can play a pivotal role in onset and progression of retinal diseases after damage of cell secretory function. In this review, we delineated the importance of cross-talk between MSCs and retinal cells, focusing on common/induced secreted factors, during experimental therapy for retinal diseases. The cross-link between the MSC and retinal cell secretomes suggests that the MSC secretome can modulate the retinal cell secretome and vice versa. For example, the MSC secretome can protect retinal cells from degeneration by reducing oxidative stress, autophagy and programmed cell death. Conversely, the retinal cell secretome can influence the MSC secretome by inducing changes in MSC gene expression and phenotype.
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Affiliation(s)
- Luigi Donato
- Department of Biomedical and Dental Sciences and Morphofunctional Imaging, University of Messina, Messina 98125, Italy
- Department of Biomolecular Strategies, Genetics and Cutting-Edge Therapies, Euro-Mediterranean Institute of Science and Technology, Palermo 90139, Italy
| | - Concetta Scimone
- Department of Biomedical and Dental Sciences and Morphofunctional Imaging, University of Messina, Messina 98125, Italy
- Department of Biomolecular Strategies, Genetics and Cutting-Edge Therapies, Euro-Mediterranean Institute of Science and Technology, Palermo 90139, Italy
| | - Simona Alibrandi
- Department of Biomedical and Dental Sciences and Morphofunctional Imaging, University of Messina, Messina 98125, Italy
- Department of Biomolecular Strategies, Genetics and Cutting-Edge Therapies, Euro-Mediterranean Institute of Science and Technology, Palermo 90139, Italy
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Messina 98125, Italy.
| | | | - Domenico Mordà
- Department of Biomedical and Dental Sciences and Morphofunctional Imaging, University of Messina, Messina 98125, Italy
- Department of Biomolecular Strategies, Genetics and Cutting-Edge Therapies, Euro-Mediterranean Institute of Science and Technology, Palermo 90139, Italy
| | - Carmela Rinaldi
- Department of Biomedical and Dental Sciences and Morphofunctional Imaging, University of Messina, Messina 98125, Italy
| | - Rosalia D'Angelo
- Department of Biomedical and Dental Sciences and Morphofunctional Imaging, University of Messina, Messina 98125, Italy
| | - Antonina Sidoti
- Department of Biomedical and Dental Sciences and Morphofunctional Imaging, University of Messina, Messina 98125, Italy
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17
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Yamamoto T, Kase S, Shinkai A, Murata M, Kikuchi K, Wu D, Kageyama Y, Shinohara M, Sasase T, Ishida S. Phosphorylation of αB-Crystallin Involves Interleukin-1β-Mediated Intracellular Retention in Retinal Müller Cells: A New Mechanism Underlying Fibrovascular Membrane Formation. Invest Ophthalmol Vis Sci 2023; 64:20. [PMID: 37459063 PMCID: PMC10362920 DOI: 10.1167/iovs.64.10.20] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/20/2023] Open
Abstract
Purpose Chronic inflammation plays a pivotal role in the pathology of proliferative diabetic retinopathy (PDR), in which biological alterations of retinal glial cells are one of the key elements. The phosphorylation of αB-crystallin/CRYAB modulates its molecular dynamics and chaperone activity, and attenuates αB-crystallin secretion via exosomes. In this study, we investigated the effect of phosphorylated αB-crystallin in retinal Müller cells on diabetic mimicking conditions, including interleukin (IL)-1β stimuli. Methods Human retinal Müller cells (MIO-M1) were used to examine gene and protein expressions with real-time quantitative PCR, enzyme linked immunosorbent assay (ELISA), and immunoblot analyses. Cell apoptosis was assessed by Caspase-3/7 assay and TdT-mediated dUTP nick-end labeling staining. Retinal tissues isolated from the Spontaneously Diabetic Torii (SDT) fatty rat, a type 2 diabetic animal model with obesity, and fibrovascular membranes from patients with PDR were examined by double-staining immunofluorescence. Results CRYAB mRNA was downregulated in MIO-M1 cells with the addition of 10 ng/mL IL-1β; however, intracellular αB-crystallin protein levels were maintained. The αB-crystallin serine 59 (Ser59) residue was phosphorylated with IL-1β application in MIO-M1 cells. Cell apoptosis in MIO-M1 cells was induced by CRYAB knockdown. Immunoreactivity for Ser59-phosphorylated αB-crystallin and glial fibrillary acidic protein was colocalized in glial cells of SDT fatty rats and fibrovascular membranes. Conclusions The Ser59 phosphorylation of αB-crystallin was modulated by IL-1β in Müller cells under diabetic mimicking inflammatory conditions, suggesting that αB-crystallin contributes to the pathogenesis of PDR through an anti-apoptotic effect.
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Affiliation(s)
- Taku Yamamoto
- Laboratory of Ocular Cell Biology and Visual Science, Department of Ophthalmology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Hokkaido, Japan
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, Missouri, United States
| | - Satoru Kase
- Laboratory of Ocular Cell Biology and Visual Science, Department of Ophthalmology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Akihiro Shinkai
- Laboratory of Ocular Cell Biology and Visual Science, Department of Ophthalmology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Miyuki Murata
- Laboratory of Ocular Cell Biology and Visual Science, Department of Ophthalmology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Kasumi Kikuchi
- Laboratory of Ocular Cell Biology and Visual Science, Department of Ophthalmology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Di Wu
- Eye Center of the Second Affiliated Hospital of Zhejiang University, School of Medicine, Hangzhou, China
| | | | | | - Tomohiko Sasase
- Biological/Pharmacological Research Laboratories, Central Pharmaceutical Research Institute, Japan Tobacco Inc., Osaka, Japan
| | - Susumu Ishida
- Laboratory of Ocular Cell Biology and Visual Science, Department of Ophthalmology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Hokkaido, Japan
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18
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Padovani-Claudio DA, Ramos CJ, Capozzi ME, Penn JS. Elucidating glial responses to products of diabetes-associated systemic dyshomeostasis. Prog Retin Eye Res 2023; 94:101151. [PMID: 37028118 PMCID: PMC10683564 DOI: 10.1016/j.preteyeres.2022.101151] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Revised: 11/21/2022] [Accepted: 11/22/2022] [Indexed: 04/08/2023]
Abstract
Diabetic retinopathy (DR) is a leading cause of blindness in working age adults. DR has non-proliferative stages, characterized in part by retinal neuroinflammation and ischemia, and proliferative stages, characterized by retinal angiogenesis. Several systemic factors, including poor glycemic control, hypertension, and hyperlipidemia, increase the risk of DR progression to vision-threatening stages. Identification of cellular or molecular targets in early DR events could allow more prompt interventions pre-empting DR progression to vision-threatening stages. Glia mediate homeostasis and repair. They contribute to immune surveillance and defense, cytokine and growth factor production and secretion, ion and neurotransmitter balance, neuroprotection, and, potentially, regeneration. Therefore, it is likely that glia orchestrate events throughout the development and progression of retinopathy. Understanding glial responses to products of diabetes-associated systemic dyshomeostasis may reveal novel insights into the pathophysiology of DR and guide the development of novel therapies for this potentially blinding condition. In this article, first, we review normal glial functions and their putative roles in the development of DR. We then describe glial transcriptome alterations in response to systemic circulating factors that are upregulated in patients with diabetes and diabetes-related comorbidities; namely glucose in hyperglycemia, angiotensin II in hypertension, and the free fatty acid palmitic acid in hyperlipidemia. Finally, we discuss potential benefits and challenges associated with studying glia as targets of DR therapeutic interventions. In vitro stimulation of glia with glucose, angiotensin II and palmitic acid suggests that: 1) astrocytes may be more responsive than other glia to these products of systemic dyshomeostasis; 2) the effects of hyperglycemia on glia are likely to be largely osmotic; 3) fatty acid accumulation may compound DR pathophysiology by promoting predominantly proinflammatory and proangiogenic transcriptional alterations of macro and microglia; and 4) cell-targeted therapies may offer safer and more effective avenues for DR treatment as they may circumvent the complication of pleiotropism in retinal cell responses. Although several molecules previously implicated in DR pathophysiology are validated in this review, some less explored molecules emerge as potential therapeutic targets. Whereas much is known regarding glial cell activation, future studies characterizing the role of glia in DR and how their activation is regulated and sustained (independently or as part of retinal cell networks) may help elucidate mechanisms of DR pathogenesis and identify novel drug targets for this blinding disease.
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Affiliation(s)
- Dolly Ann Padovani-Claudio
- Department of Ophthalmology and Visual Sciences, Vanderbilt University School of Medicine, B3321A Medical Center North, 1161 21st Avenue South, Nashville, TN, 37232-0011, USA.
| | - Carla J Ramos
- Department of Ophthalmology and Visual Sciences, Vanderbilt University School of Medicine, AA1324 Medical Center North, 1161 21st Avenue South, Nashville, TN, 37232-0011, USA.
| | - Megan E Capozzi
- Duke Molecular Physiology Institute, Duke University School of Medicine, 300 North Duke Street, Durham, NC, 27701, USA.
| | - John S Penn
- Department of Ophthalmology and Visual Sciences, Vanderbilt University School of Medicine, B3307 Medical Center North, 1161 21st Avenue South, Nashville, TN, 37232-0011, USA.
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19
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Zheng X, Wan J, Tan G. The mechanisms of NLRP3 inflammasome/pyroptosis activation and their role in diabetic retinopathy. Front Immunol 2023; 14:1151185. [PMID: 37180116 PMCID: PMC10167027 DOI: 10.3389/fimmu.2023.1151185] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Accepted: 04/11/2023] [Indexed: 05/15/2023] Open
Abstract
In the working-age population worldwide, diabetic retinopathy (DR), a prevalent complication of diabetes, is the main cause of vision impairment. Chronic low-grade inflammation plays an essential role in DR development. Recently, concerning the pathogenesis of DR, the Nod-Like Receptor Family Pyrin Domain Containing 3 (NLRP3) inflammasome in retinal cells has been determined as a causal factor. In the diabetic eye, the NLRP3 inflammasome is activated by several pathways (such as ROS and ATP). The activation of NPRP3 leads to the secretion of inflammatory cytokines interleukin-1β (IL-1β) and interleukin-18 (IL-18), and leads to pyroptosis, a rapid inflammatory form of lytic programmed cell death (PCD). Cells that undergo pyroptosis swell and rapture, releasing more inflammatory factors and accelerating DR progression. This review focuses on the mechanisms that activate NLRP3 inflammasome and pyroptosis leading to DR. The present research highlighted some inhibitors of NLRP3/pyroptosis pathways and novel therapeutic measures concerning DR treatment.
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Affiliation(s)
- Xiaoqin Zheng
- Department of Ophthalmology, The First Affiliated Hospital, Hengyang Medical School, University of South China, Hengyang, Hunan, China
| | - Jia Wan
- Department of Orthopedics, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Gang Tan
- Department of Ophthalmology, The First Affiliated Hospital, Hengyang Medical School, University of South China, Hengyang, Hunan, China
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20
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Xiaoling X, Xinmei L, Shuhua F, Qian Z, Fu G, Qifang J, Lin X, Xiong Y. TRIM40 ameliorates diabetic retinopathy through suppressing inflammation via Reelin/DAB1 signaling disruption: A mechanism by proteasomal degradation of DAB1. Biochem Biophys Res Commun 2023; 664:117-127. [PMID: 37146559 DOI: 10.1016/j.bbrc.2023.04.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2023] [Accepted: 04/08/2023] [Indexed: 05/07/2023]
Abstract
Diabetic retinopathy (DR) is a common microvascular complication of diabetes mellitus. Reelin, an extracellular matrix protein, and its effector protein Disabled1 (DAB1) have been linked to cellular events and retinal development. However, whether and how Reelin/DAB1 signaling causes DR remains to be investigated. In our study, significantly increased expression of Reelin, very low density lipoprotein receptor (VLDLR), ApoE receptor 2 (ApoER2) and phosphorylated DAB1 in retinas of streptozotocin (STZ)-induced DR mouse model was observed, along with enhanced expression of proinflammatory factors. Similar results are confirmed in high glucose (HG)-treated human retinal pigment epithelium cell line ARPE-19. Surprisingly, dysregulated tripartite motif-containing 40 (TRIM40), an E3 ubiquitin ligase, is found to be involved in DR progression by bioinformatic analysis. We observe a negative correlation between TRIM40 and p-DAB1 protein expression levels under HG conditions. Importantly, we find that TRIM40 over-expression markedly ameliorates HG-induced p-DAB1, PI3K, p-protein B kinase (AKT) and inflammatory response in HG-treated cells, but dose not affect Reelin expression. Of note, Co-IP and double immunofluorescence identify an interaction between TRIM40 and DAB1. Furthermore, we show that TRIM40 enhances K48-linked polyubiquitination of DAB1, thereby promoting DAB1 degradation. Finally, promoting TRIM40 expression by intravenous injection of the constructed adeno-associated virus (AAV-TRIM40) markedly ameliorates DR phenotypes in STZ-treated mice, as indicated by the decreased blood glucose and glycosylated hemoglobin (HbAlc) levels, and increased hemoglobin contents. Additionally, diabetes-related elevation of acellular capillaries was also meliorated in mice over-expressing TRIM40. The electroretinogram (ERG) deficits were strongly rescued in mice receiving AAV-TRIM40 injection. Moreover, AAV-TRIM40 attenuates the inflammation and p-DAB1 expression in retinal tissues of STZ-treated mice. Collectively, our findings disclose a mechanism through which TRIM40 limits DAB1 stability under physiological conditions and reveals TRIM40 as a potential therapeutic target for the intervention of Reelin/DAB1 signaling, contributing to DR treatment.
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Affiliation(s)
- Xu Xiaoling
- Department of Ophthalmology, The Second Affiliated Hospital of Nanchang University, Nanchang, 330006, China
| | - Lan Xinmei
- Department of Ophthalmology, The Second Affiliated Hospital of Nanchang University, Nanchang, 330006, China
| | - Fu Shuhua
- Department of Ophthalmology, The Second Affiliated Hospital of Nanchang University, Nanchang, 330006, China
| | - Zhang Qian
- Department of Ophthalmology, The Second Affiliated Hospital of Nanchang University, Nanchang, 330006, China
| | - Gui Fu
- Department of Ophthalmology, The Second Affiliated Hospital of Nanchang University, Nanchang, 330006, China
| | - Jin Qifang
- Department of Ophthalmology, The Second Affiliated Hospital of Nanchang University, Nanchang, 330006, China
| | - Xie Lin
- Department of Ophthalmology, The Second Affiliated Hospital of Nanchang University, Nanchang, 330006, China
| | - Yu Xiong
- Department of Ophthalmology, The Second Affiliated Hospital of Nanchang University, Nanchang, 330006, China.
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21
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Yang X, Huang Z, Xu M, Chen Y, Cao M, Yi G, Fu M. Autophagy in the retinal neurovascular unit: New perspectives into diabetic retinopathy. J Diabetes 2023; 15:382-396. [PMID: 36864557 PMCID: PMC10172025 DOI: 10.1111/1753-0407.13373] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 02/08/2023] [Accepted: 02/18/2023] [Indexed: 03/04/2023] Open
Abstract
Diabetic retinopathy (DR) is one of the most prevalent retinal disorders worldwide, and it is a major cause of vision impairment in individuals of productive age. Research has demonstrated the significance of autophagy in DR, which is a critical intracellular homeostasis mechanism required for the destruction and recovery of cytoplasmic components. Autophagy maintains the physiological function of senescent and impaired organelles under stress situations, thereby regulating cell fate via various signals. As the retina's functional and fundamental unit, the retinal neurovascular unit (NVU) is critical in keeping the retinal environment's stability and supporting the needs of retinal metabolism. However, autophagy is essential for the normal NVU structure and function. We discuss the strong association between DR and autophagy in this review, as well as the many kinds of autophagy and its crucial physiological activities in the retina. By evaluating the pathological changes of retinal NVU in DR and the latest advancements in the molecular mechanisms of autophagy that may be involved in the pathophysiology of DR in NVU, we seek to propose new ideas and methods for the prevention and treatment of DR.
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Affiliation(s)
- Xiongyi Yang
- Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong, P. R. China
- The Second Clinical School, Southern Medical University, Guangzhou, Guangdong, P. R. China
| | - Zexin Huang
- Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong, P. R. China
- The Second Clinical School, Southern Medical University, Guangzhou, Guangdong, P. R. China
| | - Mei Xu
- The Second People's Hospital of Jingmen, Jingmen, Hubei, People's Republic of China
| | - Yanxia Chen
- Department of Ophthalmology, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong, P. R. China
| | - Mingzhe Cao
- Department of Ophthalmology, The Seventh Affiliated Hospital, Sun Yat-Sen University, Shenzhen, P. R. China
| | - Guoguo Yi
- Department of Ophthalmology, The Sixth Affiliated Hospital, Sun Yat-Sen University, Guangzhou, Guangdong, P. R. China
| | - Min Fu
- Department of Ophthalmology, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong, P. R. China
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22
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Hu J, Zhu M, Li D, Wu Q, Le YZ. Critical Role of VEGF as a Direct Regulator of Photoreceptor Function. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1415:487-491. [PMID: 37440076 DOI: 10.1007/978-3-031-27681-1_71] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/14/2023]
Abstract
Vascular endothelial growth factor (VEGF or VEGF-A), a major pathogenic factor for diabetic and hypoxic blood-retina barrier (BRB) diseases, has been shown to act as a direct functional regulator for neurons in the peripheral and central nerve systems. To determine if VEGF plays a direct role in regulating retinal neuronal function, we established specific experimental procedures and examined the effect of recombinant VEGF (rVEGF) on photoreceptor function with electroretinography (ERG) in mice. In our case, rVEGF caused a significant reduction of scotopic ERG a-wave and b-wave amplitudes and photopic ERG b-wave amplitudes in a dose-dependent manner in dark-adapted wild-type (WT) mice, shortly after the intravitreal delivery of rVEGF in dark. However, the effect of rVEGF on photoreceptor function was nullified in adult Akita diabetic mice. Our data strongly suggest that VEGF is a direct regulator of photoreceptor function and VEGF upregulation contributes significantly to the diabetes-induced reduction of photoreceptor function. In this chapter, we will discuss the relevant background, key experimental procedures and results, and clinical significance of our work.
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Affiliation(s)
- Jianyan Hu
- Department of Medicine/Endocrinology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
- Department of Ophthalmology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China
| | - Meili Zhu
- Department of Medicine/Endocrinology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Dai Li
- Department of Medicine/Endocrinology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
- School of Optometry, Hubei University of Science and Technology, Xianning, China
| | - Qiang Wu
- Department of Ophthalmology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China
- Shanghai Key Laboratory of Diabetes Mellitus, Shanghai, China
| | - Yun-Zheng Le
- Department of Medicine/Endocrinology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.
- Harold Hamm Diabetes Center, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.
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23
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Liu B, He J, Zhong L, Huang L, Gong B, Hu J, Qian H, Yang Z. Single-cell transcriptome reveals diversity of Müller cells with different metabolic-mitochondrial signatures in normal and degenerated macula. Front Neurosci 2022; 16:1079498. [PMID: 36620436 PMCID: PMC9817153 DOI: 10.3389/fnins.2022.1079498] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Accepted: 12/07/2022] [Indexed: 12/24/2022] Open
Abstract
Müller cell is the most abundant glial cell in mammalian retina, supporting the functions of photoreceptors and other retinal neurons via maintaining environmental homeostasis. In response to injury and/or neuronal degeneration, Müller cells undergo morphological and functional alternations, known as reactive gliosis documented in multiple retinal diseases, including age-related macular degeneration (AMD), retinitis pigmentosa, diabetic retinopathy, and traumatic retinal detachment. But the functional consequences of Müller glia cell reactivation or even the regulatory networks of the retinal gliosis are still controversial. In this study, we reveal different subpopulations of Müller cells with distinct metabolic-mitochondrial signatures by integrating single cell transcriptomic data from Early AMD patients and healthy donors. Our results show that a portion of Müller cells exhibits low mitochondrial DNA (mtDNA) expressions, reduced protein synthesis, impaired homeostatic regulation, decreased proliferative ability but enhanced proangiogenic function. Interestingly, the major alternation of Müller cells in Early AMD retina is the change of subpopulation abundance, rather than generation of new subcluster. Transcription factor enrichment analysis further highlights the key regulators of metabolic-mitochondrial states of Müller glias in Early AMD patients especially. Our study demonstrates new characteristics of retinal gliosis associated with Early AMD and suggests the possibility to prevent degeneration by intervening mitochondrial functions of Müller cells.
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Affiliation(s)
- Bei Liu
- Sichuan Provincial Key Laboratory for Human Disease Gene Study, Sichuan Provincial People’s Hospital, University of Electronic Science and Technology of China, Chengdu, China,School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Jiali He
- School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Ling Zhong
- Sichuan Provincial Key Laboratory for Human Disease Gene Study, Sichuan Provincial People’s Hospital, University of Electronic Science and Technology of China, Chengdu, China,Research Unit for Blindness Prevention of Chinese Academy of Medical Sciences (2019RU026), Sichuan Academy of Medical Sciences, Chengdu, China
| | - Lulin Huang
- Sichuan Provincial Key Laboratory for Human Disease Gene Study, Sichuan Provincial People’s Hospital, University of Electronic Science and Technology of China, Chengdu, China,Research Unit for Blindness Prevention of Chinese Academy of Medical Sciences (2019RU026), Sichuan Academy of Medical Sciences, Chengdu, China
| | - Bo Gong
- Sichuan Provincial Key Laboratory for Human Disease Gene Study, Sichuan Provincial People’s Hospital, University of Electronic Science and Technology of China, Chengdu, China,Research Unit for Blindness Prevention of Chinese Academy of Medical Sciences (2019RU026), Sichuan Academy of Medical Sciences, Chengdu, China
| | - Jing Hu
- Sichuan Provincial Key Laboratory for Human Disease Gene Study, Sichuan Provincial People’s Hospital, University of Electronic Science and Technology of China, Chengdu, China,School of Medicine, University of Electronic Science and Technology of China, Chengdu, China,*Correspondence: Jing Hu,
| | - Hao Qian
- Sichuan Provincial Key Laboratory for Human Disease Gene Study, Sichuan Provincial People’s Hospital, University of Electronic Science and Technology of China, Chengdu, China,School of Medicine, University of Electronic Science and Technology of China, Chengdu, China,Hao Qian,
| | - Zhenglin Yang
- Sichuan Provincial Key Laboratory for Human Disease Gene Study, Sichuan Provincial People’s Hospital, University of Electronic Science and Technology of China, Chengdu, China,School of Medicine, University of Electronic Science and Technology of China, Chengdu, China,Research Unit for Blindness Prevention of Chinese Academy of Medical Sciences (2019RU026), Sichuan Academy of Medical Sciences, Chengdu, China,Zhenglin Yang,
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24
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Yang S, Qi S, Wang C. The role of retinal Müller cells in diabetic retinopathy and related therapeutic advances. Front Cell Dev Biol 2022; 10:1047487. [PMID: 36531955 PMCID: PMC9757137 DOI: 10.3389/fcell.2022.1047487] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2022] [Accepted: 11/24/2022] [Indexed: 11/19/2023] Open
Abstract
Diabetic retinopathy (DR) is a significant complication of diabetes. During the pathogenesis of retinal microangiopathy and neuronopathy, activated retinal Müller cells (RMCs) undergo morphological and structural changes such as increased expression of glial fibrillary acidic protein, disturbance of potassium and water transport regulation, and onset of production of a large number of inflammatory and vascular growth factors as well as chemokines. Evidently, activated RMCs are necessary for the pathogenesis of DR; therefore, exploring the role of RMCs in DR may provide a new target for the treatment thereof. This article reviews the mechanism of RMCs involvement in DR and the progress in related treatments.
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Affiliation(s)
| | - Shounan Qi
- Department of Ophthalmology, The Second Hospital of Jilin University, Changchun, China
| | - Chenguang Wang
- Department of Ophthalmology, The Second Hospital of Jilin University, Changchun, China
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25
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Han R, Gong R, Liu W, Xu G. Optical coherence tomography angiography metrics in different stages of diabetic macular edema. EYE AND VISION 2022; 9:14. [PMID: 35382892 PMCID: PMC8981637 DOI: 10.1186/s40662-022-00286-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Accepted: 03/15/2022] [Indexed: 11/10/2022]
Abstract
Abstract
Background
To investigate the optical coherence tomography angiography (OCTA) characteristics of diabetic macular edema (DME) at different stages.
Methods
This study was a cross-sectional study. Patients diagnosed with DME were recruited. DME was classified into early, advanced, and severe DME. The vessel density (VD) in the superficial vascular plexus (SVP), deep vascular plexus (DVP) and foveal avascular zone (FAZ) parameters, including FAZ area, FAZ perimeter, acircularity index and foveal VD in a 300-μm-wide region around the FAZ (FD-300), were calculated by the AngioVue software. A multivariate generalized estimating equation was used to evaluate the associations between visual acuity and OCTA metrics.
Results
Ninety-two eyes from 74 patients with DME were included in this study. Compared to early (P = 0.006) and advanced DME (P = 0.003), the acircularity index was higher in severe DME. Both whole and parafoveal VD in the DVP decreased in eyes with severe DME compared to early DME (P = 0.018, P = 0.005, respectively) and advanced DME (P = 0.035, P = 0.012, respectively). In the multivariate generalized estimating equation, DME severity, FAZ area and foveal thickness were positively associated with worse visual acuity (P = 0.001, P = 0.007 and P = 0.001, respectively).
Conclusion
Compared to early and advanced DME, severe DME showed increased irregularity in the FAZ and more extensive vessel damage in the DVP. Greater severity level of DME, larger FAZ area, and increased foveal thickness could be risk factors for poor visual acuity.
Trial registration The protocol was published in the Chinese Clinical Trial Registry (ChiCTR2000033082).
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26
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Fico E, Rosso P, Triaca V, Segatto M, Lambiase A, Tirassa P. NGF Prevents Loss of TrkA/VEGFR2 Cells, and VEGF Isoform Dysregulation in the Retina of Adult Diabetic Rats. Cells 2022; 11:cells11203246. [PMID: 36291113 PMCID: PMC9600509 DOI: 10.3390/cells11203246] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 10/07/2022] [Accepted: 10/11/2022] [Indexed: 11/16/2022] Open
Abstract
Among the factors involved in diabetic retinopathy (DR), nerve growth factor (NGF) and vascular endothelial growth factor A (VEGFA) have been shown to affect both neuronal survival and vascular function, suggesting that their crosstalk might influence DR outcomes. To address this question, the administration of eye drops containing NGF (ed-NGF) to adult Sprague Dawley rats receiving streptozotocin (STZ) intraperitoneal injection was used as an experimental paradigm to investigate NGF modulation of VEGFA and its receptor VEGFR2 expression. We show that ed-NGF treatment prevents the histological and vascular alterations in STZ retina, VEGFR2 expression decreased in GCL and INL, and preserved the co-expression of VEGFR2 and NGF-tropomyosin-related kinase A (TrkA) receptor in retinal ganglion cells (RGCs). The WB analysis confirmed the NGF effect on VEGFR2 expression and activation, and showed a recovery of VEGF isoform dysregulation by suppressing STZ-induced VEGFA121 expression. Reduction in inflammatory and pro-apoptotic intracellular signals were also found in STZ+NGF retina. These findings suggest that ed-NGF administration might favor neuroretina protection, and in turn counteract the vascular impairment by regulating VEGFR2 and/or VEGFA isoform expression during the early stages of the disease. The possibility that an increase in the NGF availability might contribute to the switch from the proangiogenic/apoptotic to the neuroprotective action of VEGF is discussed.
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Affiliation(s)
- Elena Fico
- Institute of Biochemistry and Cell Biology, National Research Council (CNR), Department of Sense Organs, Sapienza University of Rome, Viale del Policlinico 155, 00161 Rome, Italy
- Correspondence: (E.F.); (P.T.)
| | - Pamela Rosso
- Institute of Biochemistry and Cell Biology, National Research Council (CNR), Department of Sense Organs, Sapienza University of Rome, Viale del Policlinico 155, 00161 Rome, Italy
| | - Viviana Triaca
- Institute of Biochemistry and Cell Biology, National Research Council (CNR), International Campus A. Buzzati Traverso, Via E. Ramarini 32, Monterotondo, 00015 Rome, Italy
| | - Marco Segatto
- Department of Biosciences and Territory, University of Molise, Contrada Fonte Lappone, 86090 Pesche, Italy
| | - Alessandro Lambiase
- Department of Sense Organs, Sapienza University of Rome, Viale del Policlinico 155, 00161 Rome, Italy
| | - Paola Tirassa
- Institute of Biochemistry and Cell Biology, National Research Council (CNR), Department of Sense Organs, Sapienza University of Rome, Viale del Policlinico 155, 00161 Rome, Italy
- Correspondence: (E.F.); (P.T.)
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Tert-butylhydroquinone protects the retina from oxidative stress in STZ-induced diabetic rats via the PI3K/Akt/eNOS pathway. Eur J Pharmacol 2022; 935:175297. [PMID: 36174669 DOI: 10.1016/j.ejphar.2022.175297] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Revised: 09/19/2022] [Accepted: 09/20/2022] [Indexed: 02/07/2023]
Abstract
This study aims to investigate whether tert-butylhydroquinone protects the retina from oxidative stress in STZ-induced experimental diabetic rats through the activation of phosphinositide 3-kinase (PI3K)/Akt/endothelial nitric oxide synthase (eNOS) pathway.In vitro, NO, reactive oxygen species(ROS), eNOS, p-eNOS Ser1179, Akt, p-Akt Ser473 and L-NAME protein expression was analyzed within rMC-1 cells cultivated within normal control(NC), high glucose (HG) and HG-containing tert-butyl hydroquinone (tBHQ) (5 μM) medium. We confirmed tBHQ's protection through administering inhibitors of PI3K and Akt. In vivo, tBHQ was administered at a ratio of 1% (w/w) to diabetic rats was induced through an STZ injection (65 mg/kg) for a 3-month period, and the retinal expression of eNOS, p-eNOS Ser1179, Akt, and p-Akt Ser473 proteins was measured using Western blotting (WB) assay. We also utilized the TUNEL kit for detecting retinal cell apoptosis. The changes of retinal morphology and visual function were measured by performing hematoxylin-eosin staining (HE staining) and electroretinograms. In vitro, ROS levels were increased in the high glucose group, NO levels were decreased, and the relative expression of Akt/p-Akt Ser473 and eNOs/p-eNOS Ser1179 was reduced. tBHQ abolished these changes, and these effects were suppressed by specific inhibitors. In vivo, tBHQ upregulated retinal protein expression in STZ-induced diabetic rats, reduced retinal apoptotic cell numbers, and partially prevented abnormalities in retinal function and structure caused by diabetes. tBHQ alleviates oxidative stress during diabetic retinopathy by upregulating the PI3K/Akt/eNOS pathway and partially restoring the structure and function of the retina. It may play a role in delaying vision loss caused by diabetic retinopathy.
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28
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Rajala A, Teel K, Bhat MA, Batushansky A, Griffin TM, Purcell L, Rajala RVS. Insulin-like growth factor 1 receptor mediates photoreceptor neuroprotection. Cell Death Dis 2022; 13:613. [PMID: 35840554 PMCID: PMC9287313 DOI: 10.1038/s41419-022-05074-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 07/04/2022] [Accepted: 07/06/2022] [Indexed: 01/21/2023]
Abstract
Insulin-like growth factor I (IGF-1) is a neurotrophic factor and is the ligand for insulin-like growth factor 1 receptor (IGF-1R). Reduced expression of IGF-1 has been reported to cause deafness, mental retardation, postnatal growth failure, and microcephaly. IGF-1R is expressed in the retina and photoreceptor neurons; however, its functional role is not known. Global IGF-1 KO mice have age-related vision loss. We determined that conditional deletion of IGF-1R in photoreceptors and pan-retinal cells produces age-related visual function loss and retinal degeneration. Retinal pigment epithelial cell-secreted IGF-1 may be a source for IGF-1R activation in the retina. Altered retinal, fatty acid, and phosphoinositide metabolism are observed in photoreceptor and retinal cells lacking IGF-1R. Our results suggest that the IGF-1R pathway is indispensable for photoreceptor survival, and activation of IGF-1R may be an essential element of photoreceptor and retinal neuroprotection.
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Affiliation(s)
- Ammaji Rajala
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA
- Dean McGee Eye Institute, Oklahoma City, OK, 73104, USA
| | - Kenneth Teel
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA
- Dean McGee Eye Institute, Oklahoma City, OK, 73104, USA
| | - Mohd A Bhat
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA
- Dean McGee Eye Institute, Oklahoma City, OK, 73104, USA
| | | | | | - Lindsey Purcell
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA
- Dean McGee Eye Institute, Oklahoma City, OK, 73104, USA
| | - Raju V S Rajala
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA.
- Dean McGee Eye Institute, Oklahoma City, OK, 73104, USA.
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA.
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA.
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29
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Chen Y, Xia Q, Zeng Y, Zhang Y, Zhang M. Regulations of Retinal Inflammation: Focusing on Müller Glia. Front Cell Dev Biol 2022; 10:898652. [PMID: 35573676 PMCID: PMC9091449 DOI: 10.3389/fcell.2022.898652] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Accepted: 04/11/2022] [Indexed: 12/12/2022] Open
Abstract
Retinal inflammation underlies multiple prevalent retinal diseases. While microglia are one of the most studied cell types regarding retinal inflammation, growing evidence shows that Müller glia play critical roles in the regulation of retinal inflammation. Müller glia express various receptors for cytokines and release cytokines to regulate inflammation. Müller glia are part of the blood-retinal barrier and interact with microglia in the inflammatory responses. The unique metabolic features of Müller glia in the retina makes them vital for retinal homeostasis maintenance, regulating retinal inflammation by lipid metabolism, purine metabolism, iron metabolism, trophic factors, and antioxidants. miRNAs in Müller glia regulate inflammatory responses via different mechanisms and potentially regulate retinal regeneration. Novel therapies are explored targeting Müller glia for inflammatory retinal diseases treatment. Here we review new findings regarding the roles of Müller glia in retinal inflammation and discuss the related novel therapies for retinal diseases.
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Affiliation(s)
- Yingying Chen
- Department of Ophthalmology, Sichuan University West China Hospital, Sichuan University, Chengdu, China
- Research Laboratory of Macular Disease, West China Hospital, Sichuan University, Chengdu, China
| | - Qinghong Xia
- Operating Room of Anesthesia Surgery Center, West China Hospital, Sichuan University, Chengdu, China
- West China School of Nursing, Sichuan University, Chengdu, China
| | - Yue Zeng
- Department of Ophthalmology, Sichuan University West China Hospital, Sichuan University, Chengdu, China
- Research Laboratory of Macular Disease, West China Hospital, Sichuan University, Chengdu, China
| | - Yun Zhang
- Department of Ophthalmology, Sichuan University West China Hospital, Sichuan University, Chengdu, China
- Research Laboratory of Macular Disease, West China Hospital, Sichuan University, Chengdu, China
| | - Meixia Zhang
- Department of Ophthalmology, Sichuan University West China Hospital, Sichuan University, Chengdu, China
- Research Laboratory of Macular Disease, West China Hospital, Sichuan University, Chengdu, China
- *Correspondence: Meixia Zhang,
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30
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Zhu BT. Biochemical mechanism underlying the pathogenesis of diabetic retinopathy and other diabetic complications in humans: the methanol-formaldehyde-formic acid hypothesis. Acta Biochim Biophys Sin (Shanghai) 2022; 54:415-451. [PMID: 35607958 PMCID: PMC9828688 DOI: 10.3724/abbs.2022012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Accepted: 11/18/2021] [Indexed: 11/25/2022] Open
Abstract
Hyperglycemia in diabetic patients is associated with abnormally-elevated cellular glucose levels. It is hypothesized that increased cellular glucose will lead to increased formation of endogenous methanol and/or formaldehyde, both of which are then metabolically converted to formic acid. These one-carbon metabolites are known to be present naturally in humans, and their levels are increased under diabetic conditions. Mechanistically, while formaldehyde is a cross-linking agent capable of causing extensive cytotoxicity, formic acid is an inhibitor of mitochondrial cytochrome oxidase, capable of inducing histotoxic hypoxia, ATP deficiency and cytotoxicity. Chronic increase in the production and accumulation of these toxic one-carbon metabolites in diabetic patients can drive the pathogenesis of ocular as well as other diabetic complications. This hypothesis is supported by a large body of experimental and clinical observations scattered in the literature. For instance, methanol is known to have organ- and species-selective toxicities, including the characteristic ocular lesions commonly seen in humans and non-human primates, but not in rodents. Similarly, some of the diabetic complications (such as ocular lesions) also have a characteristic species-selective pattern, closely resembling methanol intoxication. Moreover, while alcohol consumption or combined use of folic acid plus vitamin B is beneficial for mitigating acute methanol toxicity in humans, their use also improves the outcomes of diabetic complications. In addition, there is also a large body of evidence from biochemical and cellular studies. Together, there is considerable experimental support for the proposed hypothesis that increased metabolic formation of toxic one-carbon metabolites in diabetic patients contributes importantly to the development of various clinical complications.
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Affiliation(s)
- Bao Ting Zhu
- Shenzhen Key Laboratory of Steroid Drug Discovery and DevelopmentSchool of MedicineThe Chinese University of Hong KongShenzhen518172China
- Department of PharmacologyToxicology and TherapeuticsSchool of MedicineUniversity of Kansas Medical CenterKansas CityKS66160USA
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Carpi-Santos R, de Melo Reis RA, Gomes FCA, Calaza KC. Contribution of Müller Cells in the Diabetic Retinopathy Development: Focus on Oxidative Stress and Inflammation. Antioxidants (Basel) 2022; 11:617. [PMID: 35453302 PMCID: PMC9027671 DOI: 10.3390/antiox11040617] [Citation(s) in RCA: 45] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Revised: 03/01/2022] [Accepted: 03/15/2022] [Indexed: 01/27/2023] Open
Abstract
Diabetic retinopathy is a neurovascular complication of diabetes and the main cause of vision loss in adults. Glial cells have a key role in maintenance of central nervous system homeostasis. In the retina, the predominant element is the Müller cell, a specialized cell with radial morphology that spans all retinal layers and influences the function of the entire retinal circuitry. Müller cells provide metabolic support, regulation of extracellular composition, synaptic activity control, structural organization of the blood-retina barrier, antioxidant activity, and trophic support, among other roles. Therefore, impairments of Müller actions lead to retinal malfunctions. Accordingly, increasing evidence indicates that Müller cells are affected in diabetic retinopathy and may contribute to the severity of the disease. Here, we will survey recently described alterations in Müller cell functions and cellular events that contribute to diabetic retinopathy, especially related to oxidative stress and inflammation. This review sheds light on Müller cells as potential therapeutic targets of this disease.
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Affiliation(s)
- Raul Carpi-Santos
- Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, RJ, Brazil; (R.C.-S.); (F.C.A.G.)
| | - Ricardo A. de Melo Reis
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, RJ, Brazil;
| | - Flávia Carvalho Alcantara Gomes
- Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, RJ, Brazil; (R.C.-S.); (F.C.A.G.)
| | - Karin C. Calaza
- Instituto de Biologia, Departamento de Neurobiologia, Universidade Federal Fluminense, Niteroi 24210-201, RJ, Brazil
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Evidence for Paracrine Protective Role of Exogenous αA-Crystallin in Retinal Ganglion Cells. eNeuro 2022; 9:ENEURO.0045-22.2022. [PMID: 35168949 PMCID: PMC8906792 DOI: 10.1523/eneuro.0045-22.2022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Accepted: 02/02/2022] [Indexed: 12/11/2022] Open
Abstract
Expression and secretion of neurotrophic factors have long been known as a key mechanism of neuroglial interaction in the central nervous system. In addition, several other intrinsic neuroprotective pathways have been described, including those involving small heat shock proteins such as α-crystallins. While initially considered as a purely intracellular mechanism, both αA-crystallins and αB-crystallins have been recently reported to be secreted by glial cells. While an anti-apoptotic effect of such secreted αA-crystallin has been suggested, its regulation and protective potential remain unclear. We recently identified residue threonine 148 (T148) and its phosphorylation as a critical regulator of αA-crystallin intrinsic neuroprotective function. In the current study, we explored how mutation of this residue affected αA-crystallin chaperone function, secretion, and paracrine protective function using primary glial and neuronal cells. After demonstrating the paracrine protective effect of αA-crystallins secreted by primary Müller glial cells (MGCs), we purified and characterized recombinant αA-crystallin proteins mutated on the T148 regulatory residue. Characterization of the biochemical properties of these mutants revealed an increased chaperone activity of the phosphomimetic T148D mutant. Consistent with this observation, we also show that exogeneous supplementation of the phosphomimetic T148D mutant protein protected primary retinal neurons from metabolic stress despite similar cellular uptake. In contrast, the nonphosphorylatable mutant was completely ineffective. Altogether, our study demonstrates the paracrine role of αA-crystallin in the central nervous system as well as the therapeutic potential of functionally enhanced αA-crystallin recombinant proteins to prevent metabolic-stress induced neurodegeneration.
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Pöstyéni E, Ganczer A, Kovács-Valasek A, Gabriel R. Relevance of Peptide Homeostasis in Metabolic Retinal Degenerative Disorders: Curative Potential in Genetically Modified Mice. Front Pharmacol 2022; 12:808315. [PMID: 35095518 PMCID: PMC8793341 DOI: 10.3389/fphar.2021.808315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Accepted: 12/20/2021] [Indexed: 11/19/2022] Open
Abstract
The mammalian retina contains approximately 30 neuropeptides that are synthetized by different neuronal cell populations, glia, and the pigmented epithelium. The presence of these neuropeptides leaves a mark on normal retinal molecular processes and physiology, and they are also crucial in fighting various pathologies (e.g., diabetic retinopathy, ischemia, age-related pathologies, glaucoma) because of their protective abilities. Retinal pathologies of different origin (metabolic, genetic) are extensively investigated by genetically manipulated in vivo mouse models that help us gain a better understanding of the molecular background of these pathomechanisms. These models offer opportunities to manipulate gene expression in different cell types to help reveal their roles in the preservation of retinal health or identify malfunction during diseases. In order to assess the current status of transgenic technologies available, we have conducted a literature survey focused on retinal disorders of metabolic origin, zooming in on the role of retinal neuropeptides in diabetic retinopathy and ischemia. First, we identified those neuropeptides that are most relevant to retinal pathologies in humans and the two clinically most relevant models, mice and rats. Then we continued our analysis with metabolic disorders, examining neuropeptide-related pathways leading to systemic or cellular damage and rescue. Last but not least, we reviewed the available literature on genetically modified mouse strains to understand how the manipulation of a single element of any given pathway (e.g., signal molecules, receptors, intracellular signaling pathways) could lead either to the worsening of disease conditions or, more frequently, to substantial improvements in retinal health. Most attention was given to studies which reported successful intervention against specific disorders. For these experiments, a detailed evaluation will be given and the possible role of converging intracellular pathways will be discussed. Using these converging intracellular pathways, curative effects of peptides could potentially be utilized in fighting metabolic retinal disorders.
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Affiliation(s)
- Etelka Pöstyéni
- Department of Experimental Zoology and Neurobiology, University of Pécs, Pécs, Hungary
| | - Alma Ganczer
- Department of Experimental Zoology and Neurobiology, University of Pécs, Pécs, Hungary.,János Szentágothai Research Centre, University of Pécs, Pécs, Hungary
| | - Andrea Kovács-Valasek
- Department of Experimental Zoology and Neurobiology, University of Pécs, Pécs, Hungary
| | - Robert Gabriel
- Department of Experimental Zoology and Neurobiology, University of Pécs, Pécs, Hungary.,János Szentágothai Research Centre, University of Pécs, Pécs, Hungary
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Expression of Otx Genes in Müller Cells Using an In Vitro Experimental Model of Retinal Hypoxia. J Ophthalmol 2022; 2021:6265553. [PMID: 35003791 PMCID: PMC8741358 DOI: 10.1155/2021/6265553] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Accepted: 12/03/2021] [Indexed: 11/29/2022] Open
Abstract
Introduction Müller glial cells typically activate to react to hypoxic tissue damage in several retinal diseases. We evaluated the in vitro response to a hypoxia-mimicking stimulus on the expression of a set of genes, known to contribute to eye morphogenesis and cell differentiation. Materials and Methods A MIO-M1 Müller cell line was cultured in a hypoxia-mimicking environment by the addition of cobalt chloride to the culture medium, followed by a recovery time in which we mimic restoration from the hypoxic insult. The HIF-1α protein and VEGF-A gene expression were quantified to verify the induction of a hypoxia-like state. Results Among the genes under study, we did not observe any difference in the expression levels of Otx1 and Otx2 during treatment; conversely, Otx1 was overexpressed during recovery steps. The VEGF-A gene was strongly upregulated at both the CoCl2 and recovery time points. The transactivated isoform (TA) of the TP73 gene showed an overexpression in long-term exposure to the hypoxic stimulus with a further increase after recovery. Discussion. Our molecular analysis is able to describe the activation of a set of genes, never before described, that can drive the response to a hypoxia-like status. The improved comprehension of these cellular events will be useful for designing new therapeutical approaches for retinal pathologies.
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Nonarath HJ, Hall AE, SenthilKumar G, Abroe B, Eells JT, Liedhegner ES. 670nm photobiomodulation modulates bioenergetics and oxidative stress, in rat Müller cells challenged with high glucose. PLoS One 2021; 16:e0260968. [PMID: 34860856 PMCID: PMC8641888 DOI: 10.1371/journal.pone.0260968] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Accepted: 11/21/2021] [Indexed: 12/14/2022] Open
Abstract
Diabetic retinopathy (DR), the most common complication of diabetes mellitus, is associated with oxidative stress, nuclear factor-κB (NFκB) activation, and excess production of vascular endothelial growth factor (VEGF) and intracellular adhesion molecule-1 (ICAM-1). Muller glial cells, spanning the entirety of the retina, are involved in DR inflammation. Mitigation of DR pathology currently occurs via invasive, frequently ineffective therapies which can cause adverse effects. The application of far-red to near-infrared (NIR) light (630-1000nm) reduces oxidative stress and inflammation in vitro and in vivo. Thus, we hypothesize that 670nm light treatment will diminish oxidative stress preventing downstream inflammatory mechanisms associated with DR initiated by Muller cells. In this study, we used an in vitro model system of rat Müller glial cells grown under normal (5 mM) or high (25 mM) glucose conditions and treated with a 670 nm light emitting diode array (LED) (4.5 J/cm2) or no light (sham) daily. We report that a single 670 nm light treatment diminished reactive oxygen species (ROS) production and preserved mitochondrial integrity in this in vitro model of early DR. Furthermore, treatment for 3 days in culture reduced NFκB activity to levels observed in normal glucose and prevented the subsequent increase in ICAM-1. The ability of 670nm light treatment to prevent early molecular changes in this in vitro high glucose model system suggests light treatment could mitigate early deleterious effects modulating inflammatory signaling and diminishing oxidative stress.
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Affiliation(s)
- Hannah J. Nonarath
- Department of Biomedical Sciences, College of Health Sciences, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin, United States of America
| | - Alexandria E. Hall
- Department of Biomedical Sciences, College of Health Sciences, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin, United States of America
| | - Gopika SenthilKumar
- Department of Biomedical Sciences, College of Health Sciences, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin, United States of America
| | - Betsy Abroe
- Department of Biomedical Sciences, College of Health Sciences, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin, United States of America
| | - Janis T. Eells
- Department of Biomedical Sciences, College of Health Sciences, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin, United States of America
| | - Elizabeth S. Liedhegner
- Department of Biomedical Sciences, College of Health Sciences, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin, United States of America
- * E-mail:
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Varin J, Morival C, Maillard N, Adjali O, Cronin T. Risk Mitigation of Immunogenicity: A Key to Personalized Retinal Gene Therapy. Int J Mol Sci 2021; 22:12818. [PMID: 34884622 PMCID: PMC8658027 DOI: 10.3390/ijms222312818] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Revised: 11/17/2021] [Accepted: 11/23/2021] [Indexed: 12/27/2022] Open
Abstract
Gene therapy (GT) for ocular disorders has advanced the most among adeno-associated virus (AAV)-mediated therapies, with one product already approved in the market. The bank of retinal gene mutations carefully compiled over 30 years, the small retinal surface that does not require high clinical vector stocks, and the relatively immune-privileged environment of the eye explain such success. However, adverse effects due to AAV-delivery, though rare in the retina have led to the interruption of clinical trials. Risk mitigation, as the key to safe and efficient GT, has become the focus of 'bedside-back-to-bench' studies. Herein, we overview the inflammatory adverse events described in retinal GT trials and analyze which components of the retinal immunological environment might be the most involved in these immune responses, with a focus on the innate immune system composed of microglial surveillance. We consider the factors that can influence inflammation in the retina after GT such as viral sensors in the retinal tissue and CpG content in promoters or transgene sequences. Finally, we consider options to reduce the immunological risk, including dose, modified capsids or exclusion criteria for clinical trials. A better understanding and mitigation of immune risk factors inducing host immunity in AAV-mediated retinal GT is the key to achieving safe and efficient GT.
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Affiliation(s)
| | | | | | - Oumeya Adjali
- CHU de Nantes, INSERM UMR1089, Translational Gene Therapy for Genetic Diseases, Université de Nantes, F-44200 Nantes, France; (J.V.); (C.M.); (N.M.)
| | - Therese Cronin
- CHU de Nantes, INSERM UMR1089, Translational Gene Therapy for Genetic Diseases, Université de Nantes, F-44200 Nantes, France; (J.V.); (C.M.); (N.M.)
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Qiu AW, Huang DR, Li B, Fang Y, Zhang WW, Liu QH. IL-17A injury to retinal ganglion cells is mediated by retinal Müller cells in diabetic retinopathy. Cell Death Dis 2021; 12:1057. [PMID: 34750361 PMCID: PMC8575984 DOI: 10.1038/s41419-021-04350-y] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 10/07/2021] [Accepted: 10/19/2021] [Indexed: 01/13/2023]
Abstract
Diabetic retinopathy (DR), the most common and serious ocular complication, recently has been perceived as a neurovascular inflammatory disease. However, role of adaptive immune inflammation driven by T lymphocytes in DR is not yet well elucidated. Therefore, this study aimed to clarify the role of interleukin (IL)-17A, a proinflammatory cytokine mainly produced by T lymphocytes, in retinal pathophysiology particularly in retinal neuronal death during DR process. Ins2Akita (Akita) diabetic mice 12 weeks after the onset of diabetes were used as a DR model. IL-17A-deficient diabetic mice were obtained by hybridization of IL-17A-knockout (IL-17A-KO) mouse with Akita mouse. Primarily cultured retinal Müller cells (RMCs) and retinal ganglion cells (RGCs) were treated with IL-17A in high-glucose (HG) condition. A transwell coculture of RGCs and RMCs whose IL-17 receptor A (IL-17RA) gene had been silenced with IL-17RA-shRNA was exposed to IL-17A in HG condition and the cocultured RGCs were assessed on their survival. Diabetic mice manifested increased retinal microvascular lesions, RMC activation and dysfunction, as well as RGC apoptosis. IL-17A-KO diabetic mice showed reduced retinal microvascular impairments, RMC abnormalities, and RGC apoptosis compared with diabetic mice. RMCs expressed IL-17RA. IL-17A exacerbated HG-induced RMC activation and dysfunction in vitro and silencing IL-17RA gene in RMCs abolished the IL-17A deleterious effects. In contrast, RGCs did not express IL-17RA and IL-17A did not further alter HG-induced RGC death. Notably, IL-17A aggravated HG-induced RGC death in the presence of intact RMCs but not in the presence of RMCs in which IL-17RA gene had been knocked down. These findings establish that IL-17A is actively involved in DR pathophysiology and particularly by RMC mediation it promotes RGC death. Collectively, we propose that antagonizing IL-17RA on RMCs may prevent retinal neuronal death and thereby slow down DR progression.
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Affiliation(s)
- Ao-Wang Qiu
- Department of Ophthalmology, The First Affiliated Hospital of Nanjing Medical University, 300 Guangzhou Road, 210029, Nanjing, China
| | - Da-Rui Huang
- Department of Ophthalmology, The First Affiliated Hospital of Nanjing Medical University, 300 Guangzhou Road, 210029, Nanjing, China
| | - Bin Li
- Women & Children Central Laboratory, The First Affiliated Hospital of Nanjing Medical University, 300 Guangzhou Road, 210029, Nanjing, China
| | - Yuan Fang
- Department of Ophthalmology, The First Affiliated Hospital of Nanjing Medical University, 300 Guangzhou Road, 210029, Nanjing, China
| | - Wei-Wei Zhang
- Department of Ophthalmology, The First Affiliated Hospital of Nanjing Medical University, 300 Guangzhou Road, 210029, Nanjing, China.
| | - Qing-Huai Liu
- Department of Ophthalmology, The First Affiliated Hospital of Nanjing Medical University, 300 Guangzhou Road, 210029, Nanjing, China.
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Eshwaran R, Kolibabka M, Poschet G, Jainta G, Zhao D, Teuma L, Murillo K, Hammes HP, Schmidt M, Wieland T, Feng Y. Glucosamine protects against neuronal but not vascular damage in experimental diabetic retinopathy. Mol Metab 2021; 54:101333. [PMID: 34506973 PMCID: PMC8479835 DOI: 10.1016/j.molmet.2021.101333] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2021] [Revised: 08/11/2021] [Accepted: 08/30/2021] [Indexed: 01/02/2023] Open
Abstract
Objective Glucosamine, an intermetabolite of the hexosamine biosynthesis pathway (HBP), is a widely used nutritional supplement in osteoarthritis patients, a subset of whom also suffer from diabetes. HBP is activated in diabetic retinopathy (DR). The aim of this study is to investigate the yet unclear effects of glucosamine on DR. Methods In this study, we tested the effect of glucosamine on vascular and neuronal pathology in a mouse model of streptozotocin-induced DR in vivo and on cultured endothelial and Müller cells to elucidate the underlying mechanisms of action in vitro. Results Glucosamine did not alter the blood glucose or HbA1c levels in the animals, but induced body weight gain in the non-diabetic animals. Interestingly, the impaired neuronal function in diabetic animals could be prevented by glucosamine treatment. Correspondingly, the activation of Müller cells was prevented in the retina as well as in cell culture. Conversely, glucosamine administration in the normal retina damaged the retinal vasculature by increasing pericyte loss and acellular capillary formation, likely by interfering with endothelial survival signals as seen in vitro in cultured endothelial cells. Nevertheless, under diabetic conditions, no further increase in the detrimental effects were observed. Conclusions In conclusion, the effects of glucosamine supplementation in the retina appear to be a double-edged sword: neuronal protection in the diabetic retina and vascular damage in the normal retina. Thus, glucosamine supplementation in osteoarthritis patients with or without diabetes should be taken with care.
The hexosamine biosynthesis pathway (HBP) is activated in diabetic retinopathy (DR), which manifests as vascular and neuronal damage in the retina. Glucosamine, metabolized in the HBP, is a widely used oral supplement for osteoarthritis treatment. Glucosamine supplementation improved neuronal function in retinas of mice with experimental DR, but induced vascular damage in normal retinas. Müller cell activation and endothelial survival signals in the retina were affected by glucosamine. Patients with or without diabetes should take caution with glucosamine supplementation.
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Affiliation(s)
- Rachana Eshwaran
- Experimental Pharmacology Mannheim, European Center for Angioscience, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.
| | - Matthias Kolibabka
- 5th Medical Clinic, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.
| | - Gernot Poschet
- Center for Organismal Studies (COS), Heidelberg, Germany.
| | - Gregor Jainta
- Experimental Pharmacology Mannheim, European Center for Angioscience, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.
| | - Di Zhao
- Experimental Pharmacology Mannheim, European Center for Angioscience, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.
| | - Loic Teuma
- Experimental Pharmacology Mannheim, European Center for Angioscience, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.
| | - Katharina Murillo
- 5th Medical Clinic, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.
| | - Hans-Peter Hammes
- 5th Medical Clinic, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.
| | - Martina Schmidt
- University of Groningen, Department of Molecular Pharmacology, 9713AV, Groningen, the Netherlands; University of Groningen, University Medical Center Groningen, Groningen Research Institute for Asthma and COPD (GRIAC), Groningen, the Netherlands.
| | - Thomas Wieland
- Experimental Pharmacology Mannheim, European Center for Angioscience, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany; DZHK (German Center for Cardiovascular Research), Partner site Heidelberg/Mannheim, Germany.
| | - Yuxi Feng
- Experimental Pharmacology Mannheim, European Center for Angioscience, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.
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Hu J, Zhu M, Li D, Wu Q, Le YZ. VEGF as a Direct Functional Regulator of Photoreceptors and Contributing Factor to Diabetes-Induced Alteration of Photoreceptor Function. Biomolecules 2021; 11:988. [PMID: 34356612 PMCID: PMC8301820 DOI: 10.3390/biom11070988] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Revised: 07/02/2021] [Accepted: 07/03/2021] [Indexed: 12/15/2022] Open
Abstract
Vascular endothelial growth factor (VEGF) is a major therapeutic target for blood-retina barrier (BRB) breakdown in diabetic retinopathy (DR), age-related macular degeneration (AMD), and other hypoxic retinal vascular disorders. To determine whether VEGF is a direct regulator of retinal neuronal function and its potential role in altering vision during the progression of DR, we examined the immediate impact of recombinant VEGF (rVEGF) on photoreceptor function with electroretinography in C57BL6 background wild-type (WT) and Akita spontaneous diabetic mice. Shortly after intravitreal injections, rVEGF caused a significant reduction of scotopic ERG a-wave and b-wave amplitudes and photopic ERG b-wave amplitudes in a dose-dependent manner in dark-adapted 1.5-mo-old WT mice. Compared with WT controls, 5-mo-old Akita spontaneous diabetic mice demonstrated a significant reduction in scotopic ERG a-wave and b-wave amplitudes and photopic ERG b-wave amplitudes. However, the effect of rVEGF altered photoreceptor function in WT controls was diminished in 5-mo-old Akita spontaneous diabetic mice. In conclusion, our results suggest that VEGF is a direct functional regulator of photoreceptors and VEGF up-regulation in DR is a contributing factor to diabetes-induced alteration of photoreceptor function. This information is critical to the understanding of the therapeutic effect and to the care of anti-VEGF drug-treated patients for BRB breakdown in DR, AMD, and other hypoxic retinal vascular disorders.
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Affiliation(s)
- Jianyan Hu
- Section of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; (J.H.); (M.Z.); (D.L.)
- Department of Ophthalmology, Shanghai Jiao Tong University Affiliated Sixth People’s Hospital, Shanghai 200233, China
| | - Meili Zhu
- Section of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; (J.H.); (M.Z.); (D.L.)
| | - Dai Li
- Section of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; (J.H.); (M.Z.); (D.L.)
- School of Optometry, Hubei University of Science and Technology, Xianning 437100, China
| | - Qiang Wu
- Department of Ophthalmology, Shanghai Jiao Tong University Affiliated Sixth People’s Hospital, Shanghai 200233, China
- Shanghai Key Laboratory of Diabetes Mellitus, Shanghai 200233, China
| | - Yun-Zheng Le
- Section of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; (J.H.); (M.Z.); (D.L.)
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
- Harold Hamm Diabetes Center, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
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Sagmeister S, Merl-Pham J, Petrera A, Deeg CA, Hauck SM. High glucose treatment promotes extracellular matrix proteome remodeling in Mller glial cells. PeerJ 2021; 9:e11316. [PMID: 34046254 PMCID: PMC8139267 DOI: 10.7717/peerj.11316] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Accepted: 03/30/2021] [Indexed: 11/20/2022] Open
Abstract
Background The underlying pathomechanisms in diabetic retinopathy (DR) remain incompletely understood. The aim of this study was to add to the current knowledge about the particular role of retinal Mller glial cells (RMG) in the initial processes of DR. Methods Applying a quantitative proteomic workflow, we investigated changes of primary porcine RMG under short term high glucose treatment as well as glycolysis inhibition treatment. Results We revealed significant changes in RMG proteome primarily in proteins building the extracellular matrix (ECM) indicating fundamental remodeling processes of ECM as novel rapid response to high glucose treatment. Among others, Osteopontin (SPP1) as well as its interacting integrins were significantly downregulated and organotypic retinal explant culture confirmed the selective loss of SPP1 in RMG upon treatment. Since SPP1 in the retina has been described neuroprotective for photoreceptors and functions against experimentally induced cell swelling, its rapid loss under diabetic conditions may point to a direct involvement of RMG to the early neurodegenerative processes driving DR. Data are available via ProteomeXchange with identifier PXD015879.
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Affiliation(s)
- Sandra Sagmeister
- Chair of Physiology, Department of Veterinary Sciences, LMU Munich, Martinsried, Germany.,Research Unit Protein Science and Metabolomics and Proteomics Core Facility, Helmholtz Center Munich, German Research Center for Environmental Health GmbH, Munich, Germany
| | - Juliane Merl-Pham
- Research Unit Protein Science and Metabolomics and Proteomics Core Facility, Helmholtz Center Munich, German Research Center for Environmental Health GmbH, Munich, Germany
| | - Agnese Petrera
- Research Unit Protein Science and Metabolomics and Proteomics Core Facility, Helmholtz Center Munich, German Research Center for Environmental Health GmbH, Munich, Germany
| | - Cornelia A Deeg
- Chair of Physiology, Department of Veterinary Sciences, LMU Munich, Martinsried, Germany
| | - Stefanie M Hauck
- Research Unit Protein Science and Metabolomics and Proteomics Core Facility, Helmholtz Center Munich, German Research Center for Environmental Health GmbH, Munich, Germany
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VEGF Mediates Retinal Müller Cell Viability and Neuroprotection through BDNF in Diabetes. Biomolecules 2021; 11:biom11050712. [PMID: 34068807 PMCID: PMC8150851 DOI: 10.3390/biom11050712] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Revised: 05/03/2021] [Accepted: 05/04/2021] [Indexed: 12/15/2022] Open
Abstract
To investigate the mechanism of vascular endothelial growth factor (VEGF) and brain-derived neurotrophic factor (BDNF) in Müller cell (MC) viability and neuroprotection in diabetic retinopathy (DR), we examined the role of VEGF in MC viability and BDNF production, and the effect of BDNF on MC viability under diabetic conditions. Mouse primary MCs and cells of a rat MC line, rMC1, were used in investigating MC viability and BDNF production under diabetic conditions. VEGF-stimulated BDNF production was confirmed in mice. The mechanism of BDNF-mediated MC viability was examined using siRNA knockdown. Under diabetic conditions, recombinant VEGF (rVEGF) stimulated MC viability and BDNF production in a dose-dependent manner. rBDNF also supported MC viability in a dose-dependent manner. Targeting BDNF receptor tropomyosin receptor kinase B (TRK-B) with siRNA knockdown substantially downregulated the activated (phosphorylated) form of serine/threonine-specific protein kinase (AKT) and extracellular signal-regulated kinase (ERK), classical survival and proliferation mediators. Finally, the loss of MC viability in TrkB siRNA transfected cells under diabetic conditions was rescued by rBDNF. Our results provide direct evidence that VEGF is a positive regulator for BDNF production in diabetes for the first time. This information is essential for developing BDNF-mediated neuroprotection in DR and hypoxic retinal diseases, and for improving anti-VEGF treatment for these blood-retina barrier disorders, in which VEGF is a major therapeutic target for vascular abnormalities.
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Niu T, Fang J, Shi X, Zhao M, Xing X, Wang Y, Zhu S, Liu K. Pathogenesis Study Based on High-Throughput Single-Cell Sequencing Analysis Reveals Novel Transcriptional Landscape and Heterogeneity of Retinal Cells in Type 2 Diabetic Mice. Diabetes 2021; 70:1185-1197. [PMID: 33674409 DOI: 10.2337/db20-0839] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2020] [Accepted: 02/26/2021] [Indexed: 11/13/2022]
Abstract
Diabetic retinopathy (DR) is the leading cause of acquired blindness in middle-aged people. The complex pathology of DR is difficult to dissect, given the convoluted cytoarchitecture of the retina. Here, we performed single-cell RNA sequencing (scRNA-seq) of retina from a model of type 2 diabetes, induced in leptin receptor-deficient (db/db) and control db/m mice, with the aim of elucidating the factors mediating the pathogenesis of DR. We identified 11 cell types and determined cell-type-specific expression of DR-associated loci via genome-wide association study (GWAS)-based enrichment analysis. DR also impacted cell-type-specific genes and altered cell-cell communication. Based on the scRNA-seq results, retinaldehyde-binding protein 1 (RLBP1) was investigated as a promising therapeutic target for DR. Retinal RLBP1 expression was decreased in diabetes, and its overexpression in Müller glia mitigated DR-associated neurovascular degeneration. These data provide a detailed analysis of the retina under diabetic and normal conditions, revealing new insights into pathogenic factors that may be targeted to treat DR and related dysfunctions.
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Affiliation(s)
- Tian Niu
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine; National Clinical Research Center for Eye Diseases; Shanghai Key Laboratory of Ocular Fundus Diseases; Shanghai Engineering Center for Visual Science and Photo Medicine; and Shanghai Engineering Center for Precise Diagnosis and Treatment of Eye Diseases, Shanghai, China
| | - Junwei Fang
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine; National Clinical Research Center for Eye Diseases; Shanghai Key Laboratory of Ocular Fundus Diseases; Shanghai Engineering Center for Visual Science and Photo Medicine; and Shanghai Engineering Center for Precise Diagnosis and Treatment of Eye Diseases, Shanghai, China
| | - Xin Shi
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine; National Clinical Research Center for Eye Diseases; Shanghai Key Laboratory of Ocular Fundus Diseases; Shanghai Engineering Center for Visual Science and Photo Medicine; and Shanghai Engineering Center for Precise Diagnosis and Treatment of Eye Diseases, Shanghai, China
| | - Mengya Zhao
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine; National Clinical Research Center for Eye Diseases; Shanghai Key Laboratory of Ocular Fundus Diseases; Shanghai Engineering Center for Visual Science and Photo Medicine; and Shanghai Engineering Center for Precise Diagnosis and Treatment of Eye Diseases, Shanghai, China
| | - Xindan Xing
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine; National Clinical Research Center for Eye Diseases; Shanghai Key Laboratory of Ocular Fundus Diseases; Shanghai Engineering Center for Visual Science and Photo Medicine; and Shanghai Engineering Center for Precise Diagnosis and Treatment of Eye Diseases, Shanghai, China
| | - Yihan Wang
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine; National Clinical Research Center for Eye Diseases; Shanghai Key Laboratory of Ocular Fundus Diseases; Shanghai Engineering Center for Visual Science and Photo Medicine; and Shanghai Engineering Center for Precise Diagnosis and Treatment of Eye Diseases, Shanghai, China
| | - Shaopin Zhu
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine; National Clinical Research Center for Eye Diseases; Shanghai Key Laboratory of Ocular Fundus Diseases; Shanghai Engineering Center for Visual Science and Photo Medicine; and Shanghai Engineering Center for Precise Diagnosis and Treatment of Eye Diseases, Shanghai, China
| | - Kun Liu
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine; National Clinical Research Center for Eye Diseases; Shanghai Key Laboratory of Ocular Fundus Diseases; Shanghai Engineering Center for Visual Science and Photo Medicine; and Shanghai Engineering Center for Precise Diagnosis and Treatment of Eye Diseases, Shanghai, China
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Koc F, Güven YZ, Egrilmez D, Aydın E. Optical Coherence Tomography Biomarkers in Bilateral Diabetic Macular Edema Patients with Asymmetric anti-VEGF Response. Semin Ophthalmol 2021; 36:444-451. [PMID: 33780313 DOI: 10.1080/08820538.2021.1907423] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Background: This study aimed to identify optical coherence tomography (OCT) biomarkers for predicting response to anti-VEGF treatment in diabetic macular edema (DME)Methods: Bilateral DME patients with asymmetric response to a loading dose of anti-VEGF (ranibizumab/aflibercept) treatment were retrospectively studied. The morphologic response criterion was central subfield thickness (CST) ≤300 µm; asymmetric response was defined as ≥10% difference in CST reduction between the eyes. The functional response criterion was an increase in logMAR acuity of ≥3 lines, with an increase below this threshold in the fellow eye considered asymmetric response. Relationships between final morphologic and functional responses to anti-VEGF therapy and baseline values of the following OCT-derived biomarkers were evaluated: DME subtype, CST, vitreoretinal interface anomalies, disorganization of the inner retinal layers (DRIL), external limiting membrane (ELM) disruption, ellipsoid zone (EZ) disruption, and subretinal fluid (SRF).Results: After a loading dose of anti-VEGF, 31 eyes that met both morphologic and functional response criteria were classified as responders (RR) and 27 eyes that did not respond morphologically or functionally based on the defined criteria were classified as resistant (RT). Eyes that showed only functional (n = 5) or morphological response (n = 1) were excluded due to their small number. The presence of SRF or simple epiretinal membrane (ERM) was not associated with any difference in treatment responses (p > .05), while tractional ERM, extensive DRIL (≥500 µm), and ELM and EZ disruptions in the fovea-centered 1000-µm zone were important OCT biomarkers in predicting resistance (p < .001). A multilayer perceptron model ranked predictive power as 100% for ELM disruption, 51.7% for tractional ERM, 25.4% for DRIL, and 24.5% for EZ disruption.Conclusion: Extensive ELM disruption was the strongest OCT biomarker to predict anti-VEGF resistance, followed by tractional ERM. EZ disruption and DRIL had relatively lower predictive value.
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Affiliation(s)
- Feray Koc
- Medicine, Department of Ophthalmology, Izmir Katip Celebi University, Izmir, Turkey
| | - Yusuf Ziya Güven
- Medicine, Department of Ophthalmology, Izmir Katip Celebi University, Izmir, Turkey
| | - Deniz Egrilmez
- Department of Ophthalmology, Ataturk Education and Research HospitalEye Clinic, Izmir, Turkey
| | - Erdinç Aydın
- Medicine, Department of Ophthalmology, Izmir Katip Celebi University, Izmir, Turkey
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VEGF-Independent Activation of Müller Cells by the Vitreous from Proliferative Diabetic Retinopathy Patients. Int J Mol Sci 2021; 22:ijms22042179. [PMID: 33671690 PMCID: PMC7926720 DOI: 10.3390/ijms22042179] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Revised: 02/12/2021] [Accepted: 02/19/2021] [Indexed: 02/07/2023] Open
Abstract
Proliferative diabetic retinopathy (PDR), a major complication of diabetes mellitus, results from an inflammation-sustained interplay among endothelial cells, neurons, and glia. Even though anti-vascular endothelial growth factor (VEGF) interventions represent the therapeutic option for PDR, they are only partially efficacious. In PDR, Müller cells undergo reactive gliosis, produce inflammatory cytokines/chemokines, and contribute to scar formation and retinal neovascularization. However, the impact of anti-VEGF interventions on Müller cell activation has not been fully elucidated. Here, we show that treatment of MIO-M1 Müller cells with vitreous obtained from PDR patients stimulates cell proliferation and motility, and activates various intracellular signaling pathways. This leads to cytokine/chemokine upregulation, a response that was not mimicked by treatment with recombinant VEGF nor inhibited by the anti-VEGF drug ranibizumab. In contrast, fibroblast growth factor-2 (FGF2) induced a significant overexpression of various cytokines/chemokines in MIO-M1 cells. In addition, the FGF receptor tyrosine kinase inhibitor BGJ398, the pan-FGF trap NSC12, the heparin-binding protein antagonist N-tert-butyloxycarbonyl-Phe-Leu-Phe-Leu-Phe Boc2, and the anti-inflammatory hydrocortisone all inhibited Müller cell activation mediated by PDR vitreous. These findings point to a role for various modulators beside VEGF in Müller cell activation and pave the way to the search for novel therapeutic strategies in PDR.
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Luo Y, Dong X, Lu S, Gao Y, Sun G, Sun X. Gypenoside XVII alleviates early diabetic retinopathy by regulating Müller cell apoptosis and autophagy in db/db mice. Eur J Pharmacol 2021; 895:173893. [PMID: 33493483 DOI: 10.1016/j.ejphar.2021.173893] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Revised: 01/08/2021] [Accepted: 01/14/2021] [Indexed: 01/04/2023]
Abstract
Diabetic retinopathy (DR) is a widespread vision-threatening disease in working people. Müller cells are important glial cells that participate in the blood retinal barrier and promote the maintenance of retinal physiological and structural homeostasis. Müller cell apoptosis and autophagy play an important role in the pathogenesis of DR. Gypenoside XVII (Gyp-17) exerts strong antiapoptotic and autophagic activities. However, the effect of Gyp-17 on DR and its mechanism of action have not been elucidated. This study explored the effect of Gyp-17 on early DR and Müller cell injury in db/db mice. Blood glucose and blood lipids were measured. Optical coherence tomography and fundus fluorescein angiography were applied to detect retinal thickness and vascular leakage, respectively. Hematoxylin eosin staining assessed the pathological changes of the retina. Retinal oxidative environment and cell apoptosis and autophagy were monitored using commercial kits, immunofluorescence, and Western blot assays. Results showed that Gyp-17 exerted no significant effect on blood glucose and lipid levels but maintained normal retinal permeability, physiological structure, high anti-oxidative enzyme expression, and the thickness of the inner nuclear layer compared with the model group. Moreover, Western blot analysis and TUNEL assay indicated that Gyp-17 significantly decreased pro-apoptotic-related protein expression and increased pro-autophagy-related protein expression compared with the model group. Immunofluorescence colocalization exhibited that the regulating action of Gyp-17 may focus on Müller cells. These data strongly demonstrate that Gyp-17 prevents early DR by decreasing apoptosis and increasing autophagy in Müller cells. Gyp-17 may be a candidate drug for early DR therapy.
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Affiliation(s)
- Yun Luo
- Institute of Medicinal Plant Development, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, 100193, China; Beijing Key Laboratory of Innovative Drug Discovery of Traditional Chinese Medicine (Natural Medicine) and Translational Medicine, China; Key Laboratory of Bioactive Substances and Resource Utilization of Chinese Herbal Medicine, Ministry of Education, China
| | - Xi Dong
- Institute of Medicinal Plant Development, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, 100193, China; Beijing Key Laboratory of Innovative Drug Discovery of Traditional Chinese Medicine (Natural Medicine) and Translational Medicine, China; Key Laboratory of Bioactive Substances and Resource Utilization of Chinese Herbal Medicine, Ministry of Education, China
| | - Shan Lu
- Institute of Medicinal Plant Development, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, 100193, China; Beijing Key Laboratory of Innovative Drug Discovery of Traditional Chinese Medicine (Natural Medicine) and Translational Medicine, China; Key Laboratory of Bioactive Substances and Resource Utilization of Chinese Herbal Medicine, Ministry of Education, China
| | - Ye Gao
- Institute of Medicinal Plant Development, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, 100193, China; Beijing Key Laboratory of Innovative Drug Discovery of Traditional Chinese Medicine (Natural Medicine) and Translational Medicine, China; Key Laboratory of Bioactive Substances and Resource Utilization of Chinese Herbal Medicine, Ministry of Education, China
| | - Guibo Sun
- Institute of Medicinal Plant Development, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, 100193, China; Beijing Key Laboratory of Innovative Drug Discovery of Traditional Chinese Medicine (Natural Medicine) and Translational Medicine, China; Key Laboratory of Bioactive Substances and Resource Utilization of Chinese Herbal Medicine, Ministry of Education, China.
| | - Xiaobo Sun
- Institute of Medicinal Plant Development, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, 100193, China; Beijing Key Laboratory of Innovative Drug Discovery of Traditional Chinese Medicine (Natural Medicine) and Translational Medicine, China; Key Laboratory of Bioactive Substances and Resource Utilization of Chinese Herbal Medicine, Ministry of Education, China.
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The innate immune system in diabetic retinopathy. Prog Retin Eye Res 2021; 84:100940. [PMID: 33429059 DOI: 10.1016/j.preteyeres.2021.100940] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 12/24/2020] [Accepted: 01/03/2021] [Indexed: 12/20/2022]
Abstract
The prevalence of diabetes has been rising steadily in the past half-century, along with the burden of its associated complications, including diabetic retinopathy (DR). DR is currently the most common cause of vision loss in working-age adults in the United States. Historically, DR has been diagnosed and classified clinically based on what is visible by fundoscopy; that is vasculature alterations. However, recent technological advances have confirmed pathology of the neuroretina prior to any detectable vascular changes. These, coupled with molecular studies, and the positive impact of anti-inflammatory therapeutics in DR patients have highlighted the central involvement of the innate immune system. Reminiscent of the systemic impact of diabetes, immune dysregulation has become increasingly identified as a key element of the pathophysiology of DR by interfering with normal homeostatic systems. This review uses the growing body of literature across various model systems to demonstrate the clear involvement of all three pillars of the immune system: immune-competent cells, mediators, and the complement system. It also demonstrates how the relative contribution of each of these requires more extensive analysis, including in human tissues over the continuum of disease progression. Finally, although this review demonstrates how the complex interactions of the immune system pose many more questions than answers, the intimately connected nature of the three pillars of the immune system may also point to possible new targets to reverse or even halt reverse retinopathy.
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Badia A, Salas A, Duarri A, Ferreira-de-Souza B, Zapata MÁ, Fontrodona L, García-Arumí J. Transcriptomics analysis of Ccl2/Cx3cr1/Crb1 rd8 deficient mice provides new insights into the pathophysiology of progressive retinal degeneration. Exp Eye Res 2020; 203:108424. [PMID: 33373623 DOI: 10.1016/j.exer.2020.108424] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 10/16/2020] [Accepted: 12/21/2020] [Indexed: 12/12/2022]
Abstract
Chronic oxidative stress and immune dysregulation are key mechanisms involved in the pathogenesis of most retinal degenerative diseases, including age-related macular degeneration. The Ccl2-/-/Cx3cr1-/-/Crb1rd8/rd8 mouse model develops a progressive degeneration phenotype, with photoreceptor atrophy, drusen-like lesions or pigment alterations at an early age; however, the role of oxidative stress and immune function in the pathogenesis of the model is poorly understood. We performed a comprehensive characterization of the Ccl2-/-/Cx3cr1-/-/Crb1rd8/rd8 mouse to evaluate how these pathways influence pathogenesis. We generated a Ccl2-/-/Cx3cr1-/- double-knockout (DKO) mouse on a C57BL/6N background (with the rd8 mutation of the Crb1 gene), assessed its retina status and function during 9 months in both in vivo and post-mortem analysis, and performed a comprehensive transcriptomic analysis. DKOrd8 mice presented focal retinal lesions with increased infiltration of microglia and involvement of Müller cells. Lesions progressed to thinning of the photoreceptor nuclear layer, causing a loss in retinal function. Transcriptomics analysis revealed major differential expression of genes involved in oxidative stress and neuronal function, in particular genes related to the mitochondrial electron transport chain and antioxidant cellular response. Our results suggest that alterations in chemokine signaling combined with the rd8 mutation in Ccl2-/-/Cx3cr1-/-/Crb1rd8/rd8 mice involve early changes in several pathways associated with age-related macular degeneration, highlighting the relevance of these processes in the pathological retinal degeneration in the DKOrd8 model.
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Affiliation(s)
- Anna Badia
- Ophthalmology Research, Vall d'Hebron Research Institute (VHIR), Barcelona, Spain.
| | - Anna Salas
- Ophthalmology Research, Vall d'Hebron Research Institute (VHIR), Barcelona, Spain.
| | - Anna Duarri
- Ophthalmology Research, Vall d'Hebron Research Institute (VHIR), Barcelona, Spain.
| | | | - Miguel Ángel Zapata
- Ophthalmology Research, Vall d'Hebron Research Institute (VHIR), Barcelona, Spain.
| | - Laura Fontrodona
- Ophthalmology Research, Vall d'Hebron Research Institute (VHIR), Barcelona, Spain.
| | - José García-Arumí
- Ophthalmology Research, Vall d'Hebron Research Institute (VHIR), Barcelona, Spain; Department of Ophthalmology, Hospital Universitari Vall d'Hebron, Barcelona, Spain.
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Mahato AK, Sidorova YA. RET Receptor Tyrosine Kinase: Role in Neurodegeneration, Obesity, and Cancer. Int J Mol Sci 2020; 21:ijms21197108. [PMID: 32993133 PMCID: PMC7583994 DOI: 10.3390/ijms21197108] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 09/23/2020] [Accepted: 09/24/2020] [Indexed: 02/06/2023] Open
Abstract
Rearranged during transfection (RET) is the tyrosine kinase receptor that under normal circumstances interacts with ligand at the cell surface and mediates various essential roles in a variety of cellular processes such as proliferation, differentiation, survival, migration, and metabolism. RET plays a pivotal role in the development of both peripheral and central nervous systems. RET is expressed from early stages of embryogenesis and remains expressed throughout all life stages. Mutations either activating or inhibiting RET result in several aggressive diseases, namely cancer and Hirschsprung disease. However, the physiological ligand-dependent activation of RET receptor is important for the survival and maintenance of several neuronal populations, appetite, and weight gain control, thus providing an opportunity for the development of disease-modifying therapeutics against neurodegeneration and obesity. In this review, we describe the structure of RET, its signaling, and its role in both normal conditions as well as in several disorders. We highlight the differences in the signaling and outcomes of constitutive and ligand-induced RET activation. Finally, we review the data on recently developed small molecular weight RET agonists and their potential for the treatment of various diseases.
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Rossino MG, Lulli M, Amato R, Cammalleri M, Dal Monte M, Casini G. Oxidative Stress Induces a VEGF Autocrine Loop in the Retina: Relevance for Diabetic Retinopathy. Cells 2020; 9:E1452. [PMID: 32545222 PMCID: PMC7349409 DOI: 10.3390/cells9061452] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2020] [Revised: 06/01/2020] [Accepted: 06/10/2020] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Oxidative stress (OS) plays a central role in diabetic retinopathy (DR), triggering expression and release of vascular endothelial growth factor (VEGF), the increase of which leads to deleterious vascular changes. We tested the hypothesis that OS-stimulated VEGF induces its own expression with an autocrine mechanism. METHODS MIO-M1 cells and ex vivo mouse retinal explants were treated with OS, with exogenous VEGF or with conditioned media (CM) from OS-stressed cultures. RESULTS Both in MIO-M1 cells and in retinal explants, OS or exogenous VEGF induced a significant increase of VEGF mRNA, which was abolished by VEGF receptor 2 (VEGFR-2) inhibition. OS also caused VEGF release. In MIO-M1 cells, CM induced VEGF expression, which was abolished by a VEGFR-2 inhibitor. Moreover, the OS-induced increase of VEGF mRNA was abolished by a nuclear factor erythroid 2-related factor 2 (Nrf2) blocker, while the effect of exo-VEGF resulted Nrf2-independent. Finally, both the exo-VEGF- and the OS-induced increase of VEGF expression were blocked by a hypoxia-inducible factor-1 inhibitor. CONCLUSIONS These results are consistent with the existence of a retinal VEGF autocrine loop triggered by OS. This mechanism may significantly contribute to the maintenance of elevated VEGF levels and therefore it may be of central importance for the onset and development of DR.
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Affiliation(s)
- Maria Grazia Rossino
- Department of Biology, University of Pisa, 56126 Pisa, Italy; (M.G.R.); (R.A.); (M.C.)
| | - Matteo Lulli
- Department of Experimental and Clinical Biomedical Sciences “Mario Serio”, University of Florence, 50134 Florence, Italy;
| | - Rosario Amato
- Department of Biology, University of Pisa, 56126 Pisa, Italy; (M.G.R.); (R.A.); (M.C.)
| | - Maurizio Cammalleri
- Department of Biology, University of Pisa, 56126 Pisa, Italy; (M.G.R.); (R.A.); (M.C.)
- Interdepartmental Research Center Nutrafood “Nutraceuticals and Food for Health”, University of Pisa, 56124 Pisa, Italy
| | - Massimo Dal Monte
- Department of Biology, University of Pisa, 56126 Pisa, Italy; (M.G.R.); (R.A.); (M.C.)
- Interdepartmental Research Center Nutrafood “Nutraceuticals and Food for Health”, University of Pisa, 56124 Pisa, Italy
| | - Giovanni Casini
- Department of Biology, University of Pisa, 56126 Pisa, Italy; (M.G.R.); (R.A.); (M.C.)
- Interdepartmental Research Center Nutrafood “Nutraceuticals and Food for Health”, University of Pisa, 56124 Pisa, Italy
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Ma M, Zhao S, Zhang J, Sun T, Fan Y, Zheng Z. High Glucose-Induced TRPC6 Channel Activation Decreases Glutamate Uptake in Rat Retinal Müller Cells. Front Pharmacol 2020; 10:1668. [PMID: 32116675 PMCID: PMC7033573 DOI: 10.3389/fphar.2019.01668] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Accepted: 12/20/2019] [Indexed: 12/15/2022] Open
Abstract
High glucose (HG) increases the production of reactive oxygen species (ROS), leading to decreased glutamate uptake in Müller cells. The transient receptor potential cation channel 6 (TRPC6) channel, an oxidative stress-sensitive Ca2+-permeable cationic channel, is readily detected in Müller cells and highly expressed under HG conditions. Yet, the effect of high glucose-induced TRPC6 channel activation in Müller cells is poorly understood. We hypothesized that TRPC6 channel activation mediates high glucose-induced decreases in Müller cell glutamate uptake. We found RNA interference (RNAi) of the TRPC6 channel abolished HG-induced decreases in glutamate uptake and cell death. HG also decreased the expression of the glutamate-aspartate transporter (GLAST), which is the most important transporter involved in glutamate uptake. The mRNA level of ciliary neurotrophic factor (CNTF) in rMC-1 cells and the release of CNTF in the culture media was decreased, but the mRNA levels of IL-6 and vascular endothelial growth factor (VEGF) were increased under HG conditions. After RNAi silencing in rMC-1 cells, the mRNA levels of CNTF increased, but IL-6 and VEGF levels decreased. Furthermore, TRPC6 knockdown (KD) decreased expression of glial fibrillary acidic protein (GFAP) and increased expression of Kir4.1, pointing to inhibition of HG-induced gliosis in rMC-1 cells. ROS and intracellular Ca2+ levels decreased after TRPC6 knockdown. Exposure to Hyp9 (10 μM), a highly selective TRPC6 channel agonist, can aggravate HG-induced pathological changes. Collectively, our results suggest TRPC6 channel activation is involved in HG-induced decreases in glutamate uptake in rMC-1 cells. These findings provide novel insights into the role of TRPC6 in HG-induced retinal neurovasculopathy and suggest TRPC6 is a promising target for drug development for diabetic retinopathy (DR).
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Affiliation(s)
- Mingming Ma
- Department of Ophthalmology, Shanghai General Hospital, Shanghai, China.,National Clinical Research Center for Eye Diseases, Shanghai, China.,Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai Jiao Tong University, Shanghai, China.,Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai General Hospital, Shanghai Jiao Tong University, Shanghai, China.,Shanghai Engineering Center for Precise Diagnosis and Treatment of Eye Diseases, Shanghai, China
| | - Shuzhi Zhao
- Department of Ophthalmology, Shanghai General Hospital, Shanghai, China.,National Clinical Research Center for Eye Diseases, Shanghai, China.,Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai Jiao Tong University, Shanghai, China.,Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai General Hospital, Shanghai Jiao Tong University, Shanghai, China.,Shanghai Engineering Center for Precise Diagnosis and Treatment of Eye Diseases, Shanghai, China
| | - Jian Zhang
- Department of Ophthalmology, Shanghai General Hospital, Shanghai, China.,National Clinical Research Center for Eye Diseases, Shanghai, China.,Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai Jiao Tong University, Shanghai, China.,Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai General Hospital, Shanghai Jiao Tong University, Shanghai, China.,Shanghai Engineering Center for Precise Diagnosis and Treatment of Eye Diseases, Shanghai, China
| | - Tao Sun
- Department of Ophthalmology, Shanghai General Hospital, Shanghai, China.,National Clinical Research Center for Eye Diseases, Shanghai, China.,Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai Jiao Tong University, Shanghai, China.,Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai General Hospital, Shanghai Jiao Tong University, Shanghai, China.,Shanghai Engineering Center for Precise Diagnosis and Treatment of Eye Diseases, Shanghai, China
| | - Ying Fan
- Department of Ophthalmology, Shanghai General Hospital, Shanghai, China.,National Clinical Research Center for Eye Diseases, Shanghai, China.,Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai Jiao Tong University, Shanghai, China.,Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai General Hospital, Shanghai Jiao Tong University, Shanghai, China.,Shanghai Engineering Center for Precise Diagnosis and Treatment of Eye Diseases, Shanghai, China
| | - Zhi Zheng
- Department of Ophthalmology, Shanghai General Hospital, Shanghai, China.,National Clinical Research Center for Eye Diseases, Shanghai, China.,Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai Jiao Tong University, Shanghai, China.,Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai General Hospital, Shanghai Jiao Tong University, Shanghai, China.,Shanghai Engineering Center for Precise Diagnosis and Treatment of Eye Diseases, Shanghai, China
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