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Cui S, Li J, Zhang C, Li Q, Jiang C, Wang X, Yu X, Li K, Feng Y, Jian F. Glial scarring limits recovery following decompressive surgery in rats with syringomyelia. Exp Neurol 2025; 385:115113. [PMID: 39667655 DOI: 10.1016/j.expneurol.2024.115113] [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: 09/26/2024] [Revised: 11/28/2024] [Accepted: 12/08/2024] [Indexed: 12/14/2024]
Abstract
Syringomyelia is a neurological disease that is difficult to cure, and treatments often have limited effectiveness. In this study, a rat model of syringomyelia induced by epidural compression was used to investigate the factors that limit the prognosis of syringomyelia. After we treated syringomyelia rats with surgical decompression alone, MRI revealed that the syringomyelia rats did not show the expected therapeutic effect. Through cerebrospinal fluid (CSF) tracing experiments, we found that the CSF flow in the subarachnoid space (SAS) of rats was restored after decompression. This shows that the poor prognosis of syringomyelia rats in this study is not caused by CSF circulation disorders, suggesting the existence of other factors. Further, immunofluorescence revealed that there were extensive glial scars characterized by increased expression of glial fibrillary acidic protein (GFAP) and chondroitin sulfate proteoglycans (CSPGs) around the syrinx in the non-improved group compared to the improved group. To verify the limiting role of glial scarring in the prognosis of syringomyelia, we intervened with the selective astrocyte inhibitor fluorocitrate (FC). Intrathecal injection of FC significantly inhibited the formation of glial scar after decompression in syringomyelia rats and promoted the reduction of syrinx. This scar-inhibiting effect significantly improved neuronal survival, promoted axonal and myelin recovery, and showed better recovery in sensory function and fine motor control functions. These findings suggest that glial scarring around syrinx is a key factor limiting recovery of syringomyelia. By inhibiting glial scar formation, the prognosis of syringomyelia can be significantly improved, which provides a new strategy for improving clinical treatment effects.
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Affiliation(s)
- Shengyu Cui
- Department of Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China; Spine Center, China International Neuroscience Institute (CHINA-INI), Beijing, China; Research Center of Spine and Spinal Cord, Beijing Institute of Brain Disorders, Capital Medical University, Beijing, China; Lab of Spinal Cord Injury and Functional Reconstruction, China International Neuroscience Institute (CHINA-INI), Xuanwu Hospital, Capital Medical University, Beijing, China.
| | - Jinze Li
- Department of Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China; Spine Center, China International Neuroscience Institute (CHINA-INI), Beijing, China; Research Center of Spine and Spinal Cord, Beijing Institute of Brain Disorders, Capital Medical University, Beijing, China; Lab of Spinal Cord Injury and Functional Reconstruction, China International Neuroscience Institute (CHINA-INI), Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Can Zhang
- Department of Neurosurgery, The First Hospital of Hebei Medical University, Shijiazhuang, China
| | - Qian Li
- Department of Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China; Spine Center, China International Neuroscience Institute (CHINA-INI), Beijing, China; Research Center of Spine and Spinal Cord, Beijing Institute of Brain Disorders, Capital Medical University, Beijing, China; Lab of Spinal Cord Injury and Functional Reconstruction, China International Neuroscience Institute (CHINA-INI), Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Chuan Jiang
- Department of Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China; Spine Center, China International Neuroscience Institute (CHINA-INI), Beijing, China; Research Center of Spine and Spinal Cord, Beijing Institute of Brain Disorders, Capital Medical University, Beijing, China; Lab of Spinal Cord Injury and Functional Reconstruction, China International Neuroscience Institute (CHINA-INI), Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Xinyu Wang
- Baylor College of Medicine, Houston, TX, USA
| | - Xiaoxu Yu
- Department of Critical Care Medicine, Beijing Tsinghua Changgung Hospital, School of Clinical Medicine, Tsinghua University, Beijing, China
| | - Kang Li
- Department of Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China; Spine Center, China International Neuroscience Institute (CHINA-INI), Beijing, China; Research Center of Spine and Spinal Cord, Beijing Institute of Brain Disorders, Capital Medical University, Beijing, China; Lab of Spinal Cord Injury and Functional Reconstruction, China International Neuroscience Institute (CHINA-INI), Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Yuxin Feng
- Capital Medical University, Beijing, China
| | - Fengzeng Jian
- Department of Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China; Spine Center, China International Neuroscience Institute (CHINA-INI), Beijing, China; Research Center of Spine and Spinal Cord, Beijing Institute of Brain Disorders, Capital Medical University, Beijing, China; Lab of Spinal Cord Injury and Functional Reconstruction, China International Neuroscience Institute (CHINA-INI), Xuanwu Hospital, Capital Medical University, Beijing, China.
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Sekiya T, Holley MC. The Glial Scar: To Penetrate or Not for Motor Pathway Restoration? Cell Transplant 2025; 34:9636897251315271. [PMID: 40152462 PMCID: PMC11951902 DOI: 10.1177/09636897251315271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2024] [Revised: 12/25/2024] [Accepted: 01/08/2025] [Indexed: 03/29/2025] Open
Abstract
Although notable progress has been made, restoring motor function from the brain to the muscles continues to be a substantial clinical challenge in motor neuron diseases/disorders such as spinal cord injury (SCI). While cell transplantation has been widely explored as a potential therapeutic method for reconstructing functional motor pathways, there remains considerable opportunity for enhancing its therapeutic effectiveness. We reviewed studies on motor pathway regeneration to identify molecular and ultrastructural cues that could enhance the efficacy of cell transplantation. While the glial scar is often cited as an intractable barrier to axon regeneration, this mainly applies to axons trying to penetrate its "core" to reach the opposite side. However, the glial scar exhibits a "duality," with an anti-regenerative core and a pro-regenerative "surface." This surface permissiveness is attributed to pro-regenerative molecules, such as laminin in the basement membrane (BM). Transplanting donor cells onto the BM, which forms plastically after injury, may significantly enhance the efficacy of cell transplantation. Specifically, forming detour pathways between transplanted cells and endogenous propriospinal neurons on the pro-regenerative BM may efficiently bypass the intractable scar core and promote motor pathway regeneration. We believe harnessing the tissue's innate repair capacity is crucial, and targeting post-injury plasticity in astrocytes and Schwann cells, especially those associated with the BM that has predominantly been overlooked in the field of SCI research, can advance motor system restoration to a new stage. A shift in cell delivery routes-from the traditional intra-parenchymal (InP) route to the transplantation of donor cells onto the pro-regenerative BM via the extra-parenchymal (ExP) route-may signify a transformative step forward in neuro-regeneration research. Practically, however, the complementary use of both InP and ExP methods may offer the most substantial benefit for restoring motor pathways. We aim for this review to deepen the understanding of cell transplantation and provide a framework for evaluating the efficacy of this therapeutic modality in comparison to others.
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Affiliation(s)
- Tetsuji Sekiya
- Department of Otolaryngology-Head and Neck Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan
- Department of Neurological Surgery, Hikone Chuo Hospital, Hikone, Japan
| | - Matthew C. Holley
- Department of Biomedical Science, University of Sheffield, Sheffield, England
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Delgado T, Emerson J, Hong M, Keillor JW, Johnson GVW. Pharmacological Inhibition of Astrocytic Transglutaminase 2 Facilitates the Expression of a Neurosupportive Astrocyte Reactive Phenotype in Association with Increased Histone Acetylation. Biomolecules 2024; 14:1594. [PMID: 39766301 PMCID: PMC11673777 DOI: 10.3390/biom14121594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2024] [Revised: 12/02/2024] [Accepted: 12/09/2024] [Indexed: 01/11/2025] Open
Abstract
Astrocytes play critical roles in supporting structural and metabolic homeostasis in the central nervous system (CNS). CNS injury leads to the development of a range of reactive phenotypes in astrocytes whose molecular determinants are poorly understood. Finding ways to modulate astrocytic injury responses and leverage a pro-recovery phenotype holds promise in treating CNS injury. Recently, it has been demonstrated that ablation of astrocytic transglutaminase 2 (TG2) shifts reactive astrocytes towards a phenotype that improves neuronal injury outcomes both in vitro and in vivo. Additionally, in an in vivo mouse model, pharmacological inhibition of TG2 with the irreversible inhibitor VA4 phenocopied the neurosupportive effects of TG2 deletion in astrocytes. In this study, we extended our comparisons of VA4 treatment and TG2 deletion to provide insights into the mechanisms by which TG2 attenuates neurosupportive astrocytic function after injury. Using a neuron-astrocyte co-culture model, we found that VA4 treatment improves the ability of astrocytes to support neurite outgrowth on an injury-relevant matrix, as we previously showed for astrocytic TG2 deletion. We hypothesize that TG2 mediates its influence on astrocytic phenotype through transcriptional regulation, and our previous RNA sequencing suggests that TG2 is primarily transcriptionally repressive in astrocytes, although it can facilitate both up- and downregulation of gene expression. Therefore, we asked whether VA4 inhibition could alter TG2's interaction with Zbtb7a, a transcription factor that we previously identified as a functionally relevant TG2 nuclear interactor. We found that VA4 significantly decreased the interaction of TG2 and Zbtb7a. Additionally, we assessed the effect of TG2 deletion and VA4 treatment on transcriptionally permissive histone acetylation and found significantly greater acetylation in both experimental groups. Consistent with these findings, our present proteomic analysis further supports the predominant transcriptionally repressive role of TG2 in astrocytes. Our proteomic data additionally unveiled pronounced changes in lipid and antioxidant metabolism in astrocytes with TG2 deletion or inhibition, which likely contribute to the enhanced neurosupportive function of these astrocytes.
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Affiliation(s)
- Thomas Delgado
- Department of Anesthesiology and Perioperative Medicine, University of Rochester, 601 Elmwood Ave, Box 604, Rochester, NY 14620, USA; (T.D.); (J.E.); (M.H.)
| | - Jacen Emerson
- Department of Anesthesiology and Perioperative Medicine, University of Rochester, 601 Elmwood Ave, Box 604, Rochester, NY 14620, USA; (T.D.); (J.E.); (M.H.)
| | - Matthew Hong
- Department of Anesthesiology and Perioperative Medicine, University of Rochester, 601 Elmwood Ave, Box 604, Rochester, NY 14620, USA; (T.D.); (J.E.); (M.H.)
| | - Jeffrey W. Keillor
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, ON K1N6N5, Canada;
| | - Gail V. W. Johnson
- Department of Anesthesiology and Perioperative Medicine, University of Rochester, 601 Elmwood Ave, Box 604, Rochester, NY 14620, USA; (T.D.); (J.E.); (M.H.)
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Delgado T, Emerson J, Hong M, Keillor JW, Johnson GVW. Pharmacological inhibition of astrocytic transglutaminase 2 facilitates the expression of a neurosupportive astrocyte reactive phenotype in association with increased histone acetylation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.15.589192. [PMID: 38659783 PMCID: PMC11042235 DOI: 10.1101/2024.04.15.589192] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/26/2024]
Abstract
Astrocytes play critical roles in supporting structural and metabolic homeostasis in the central nervous system (CNS). CNS injury leads to the development of a range of reactive phenotypes in astrocytes whose molecular determinants are poorly understood. Finding ways to modulate astrocytic injury responses and leverage a pro-recovery phenotype holds promise in treating CNS injury. Recently, it has been demonstrated that ablation of astrocytic transglutaminase 2 (TG2) modulates the phenotype of reactive astrocytes in a way that improves neuronal injury outcomes both in vitro and in vivo. In an in vivo mouse model, pharmacological inhibition of TG2 with the irreversible inhibitor VA4 phenocopies the neurosupportive effects of TG2 deletion in astrocytes. In this study, we provide insights into the mechanisms by which TG2 deletion or inhibition result in a more neurosupportive astrocytic phenotype. Using a neuron-astrocyte co-culture model, we show that VA4 treatment improves the ability of astrocytes to support neurite outgrowth on an injury-relevant matrix. To better understand how pharmacologically altering TG2 affects its ability to regulate reactive astrocyte phenotypes, we assessed how VA4 inhibition impacts TG2's interaction with Zbtb7a, a transcription factor we have previously identified as a functionally relevant TG2 nuclear interactor. The results of these studies demonstrate that VA4 significantly decreases the interaction of TG2 and Zbtb7a. TG2's interactions with Zbtb7a, as well as a wide range of other transcription factors and chromatin regulatory proteins, suggest that TG2 may act as an epigenetic regulator to modulate gene expression. To begin to understand if TG2-mediated epigenetic modification may impact astrocytic phenotypes in our models, we interrogated the effect of TG2 deletion and VA4 treatment on histone acetylation and found significantly greater acetylation in both experimental groups. Consistent with these findings, previous RNA-sequencing and our present proteomic analysis also supported a predominant transcriptionally suppressive role of TG2 in astrocytes. Our proteomic data additionally unveiled pronounced changes in lipid and antioxidant metabolism in astrocytes with TG2 deletion or inhibition, which likely contribute to the enhanced neurosupportive function of these astrocytes.
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Affiliation(s)
- Thomas Delgado
- 601 Elmwood Ave, box 604, Department of Anesthesiology and Perioperative Medicine, University of Rochester, Rochester, NY, 14620, USA
| | - Jacen Emerson
- 601 Elmwood Ave, box 604, Department of Anesthesiology and Perioperative Medicine, University of Rochester, Rochester, NY, 14620, USA
| | - Matthew Hong
- 601 Elmwood Ave, box 604, Department of Anesthesiology and Perioperative Medicine, University of Rochester, Rochester, NY, 14620, USA
| | - Jeffrey W. Keillor
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, ON K1N6N5, Canada
| | - Gail VW Johnson
- 601 Elmwood Ave, box 604, Department of Anesthesiology and Perioperative Medicine, University of Rochester, Rochester, NY, 14620, USA
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Delgado T, Emerson J, Hong M, Keillor JW, Johnson GVW. Pharmacological inhibition of astrocytic transglutaminase 2 facilitates the expression of a neurosupportive astrocyte reactive phenotype in association with increased histone acetylation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.02.06.527263. [PMID: 36798305 PMCID: PMC9934526 DOI: 10.1101/2023.02.06.527263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Astrocytes play critical roles in supporting structural and metabolic homeostasis in the central nervous system (CNS). CNS injury leads to the development of a range of reactive phenotypes in astrocytes whose molecular determinants are poorly understood. Finding ways to modulate astrocytic injury responses and leverage a pro-recovery phenotype holds promise in treating CNS injury. Recently, it has been demonstrated that ablation of astrocytic transglutaminase 2 (TG2) modulates the phenotype of reactive astrocytes in a way that improves neuronal injury outcomes both in vitro and in vivo. In an in vivo mouse model, pharmacological inhibition of TG2 with the irreversible inhibitor VA4 phenocopies the neurosupportive effects of TG2 deletion in astrocytes. In this study, we provide insights into the mechanisms by which TG2 deletion or inhibition result in a more neurosupportive astrocytic phenotype. Using a neuron-astrocyte co-culture model, we show that VA4 treatment improves the ability of astrocytes to support neurite outgrowth on an injury-relevant matrix. To better understand how pharmacologically altering TG2 affects its ability to regulate reactive astrocyte phenotypes, we assessed how VA4 inhibition impacts TG2's interaction with Zbtb7a, a transcription factor we have previously identified as a functionally relevant TG2 nuclear interactor. The results of these studies demonstrate that VA4 significantly decreases the interaction of TG2 and Zbtb7a. TG2's interactions with Zbtb7a, as well as a wide range of other transcription factors and chromatin regulatory proteins, suggest that TG2 may act as an epigenetic regulator to modulate gene expression. To begin to understand if TG2-mediated epigenetic modification may impact astrocytic phenotypes in our models, we interrogated the effect of TG2 deletion and VA4 treatment on histone acetylation and found significantly greater acetylation in both experimental groups. Consistent with these findings, previous RNA-sequencing and our present proteomic analysis also supported a predominant transcriptionally suppressive role of TG2 in astrocytes. Our proteomic data additionally unveiled pronounced changes in lipid and antioxidant metabolism in astrocytes with TG2 deletion or inhibition, which likely contribute to the enhanced neurosupportive function of these astrocytes.
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Affiliation(s)
- Thomas Delgado
- 601 Elmwood Ave, box 604, Department of Anesthesiology and Perioperative Medicine, University of Rochester, Rochester, NY, 14620, USA
| | - Jacen Emerson
- 601 Elmwood Ave, box 604, Department of Anesthesiology and Perioperative Medicine, University of Rochester, Rochester, NY, 14620, USA
| | - Matthew Hong
- 601 Elmwood Ave, box 604, Department of Anesthesiology and Perioperative Medicine, University of Rochester, Rochester, NY, 14620, USA
| | - Jeffrey W. Keillor
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, ON K1N6N5, Canada
| | - Gail VW Johnson
- 601 Elmwood Ave, box 604, Department of Anesthesiology and Perioperative Medicine, University of Rochester, Rochester, NY, 14620, USA
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Brandt N, Köper F, Hausmann J, Bräuer AU. Spotlight on plasticity-related genes: Current insights in health and disease. Pharmacol Ther 2024; 260:108687. [PMID: 38969308 DOI: 10.1016/j.pharmthera.2024.108687] [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: 02/08/2024] [Revised: 06/07/2024] [Accepted: 07/02/2024] [Indexed: 07/07/2024]
Abstract
The development of the central nervous system is highly complex, involving numerous developmental processes that must take place with high spatial and temporal precision. This requires a series of complex and well-coordinated molecular processes that are tighly controlled and regulated by, for example, a variety of proteins and lipids. Deregulations in these processes, including genetic mutations, can lead to the most severe maldevelopments. The present review provides an overview of the protein family Plasticity-related genes (PRG1-5), including their role during neuronal differentiation, their molecular interactions, and their participation in various diseases. As these proteins can modulate the function of bioactive lipids, they are able to influence various cellular processes. Furthermore, they are dynamically regulated during development, thus playing an important role in the development and function of synapses. First studies, conducted not only in mouse experiments but also in humans, revealed that mutations or dysregulations of these proteins lead to changes in lipid metabolism, resulting in severe neurological deficits. In recent years, as more and more studies have shown their involvement in a broad range of diseases, the complexity and broad spectrum of known and as yet unknown interactions between PRGs, lipids, and proteins make them a promising and interesting group of potential novel therapeutic targets.
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Affiliation(s)
- Nicola Brandt
- Research Group Anatomy, Department of Human Medicine, School of Medicine and Health Sciences, Carl von Ossietzky University Oldenburg, Oldenburg, Germany
| | - Franziska Köper
- Research Group Anatomy, Department of Human Medicine, School of Medicine and Health Sciences, Carl von Ossietzky University Oldenburg, Oldenburg, Germany
| | - Jens Hausmann
- Research Group Anatomy, Department of Human Medicine, School of Medicine and Health Sciences, Carl von Ossietzky University Oldenburg, Oldenburg, Germany
| | - Anja U Bräuer
- Research Group Anatomy, Department of Human Medicine, School of Medicine and Health Sciences, Carl von Ossietzky University Oldenburg, Oldenburg, Germany; Research Center for Neurosensory Science, Carl von Ossietzky University Oldenburg, Oldenburg, Germany.
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Hingorani S, Paniagua Soriano G, Sánchez Huertas C, Villalba Riquelme EM, López Mocholi E, Martínez Rojas B, Alastrué Agudo A, Dupraz S, Ferrer Montiel AV, Moreno Manzano V. Transplantation of dorsal root ganglia overexpressing the NaChBac sodium channel improves locomotion after complete SCI. Mol Ther 2024; 32:1739-1759. [PMID: 38556794 PMCID: PMC11184342 DOI: 10.1016/j.ymthe.2024.03.038] [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: 12/06/2023] [Revised: 02/21/2024] [Accepted: 03/28/2024] [Indexed: 04/02/2024] Open
Abstract
Spinal cord injury (SCI) is a debilitating condition currently lacking treatment. Severe SCI causes the loss of most supraspinal inputs and neuronal activity caudal to the injury, which, coupled with the limited endogenous capacity for spontaneous regeneration, can lead to complete functional loss even in anatomically incomplete lesions. We hypothesized that transplantation of mature dorsal root ganglia (DRGs) genetically modified to express the NaChBac sodium channel could serve as a therapeutic option for functionally complete SCI. We found that NaChBac expression increased the intrinsic excitability of DRG neurons and promoted cell survival and neurotrophic factor secretion in vitro. Transplantation of NaChBac-expressing dissociated DRGs improved voluntary locomotion 7 weeks after injury compared to control groups. Animals transplanted with NaChBac-expressing DRGs also possessed higher tubulin-positive neuronal fiber and myelin preservation, although serotonergic descending fibers remained unaffected. We observed early preservation of the corticospinal tract 14 days after injury and transplantation, which was lost 7 weeks after injury. Nevertheless, transplantation of NaChBac-expressing DRGs increased the neuronal excitatory input by an increased number of VGLUT2 contacts immediately caudal to the injury. Our work suggests that the transplantation of NaChBac-expressing dissociated DRGs can rescue significant motor function, retaining an excitatory neuronal relay activity immediately caudal to injury.
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Affiliation(s)
- Sonia Hingorani
- Neuronal and Tissue Regeneration Laboratory, Centro de Investigación Príncipe Felipe, 46012 Valencia, Spain
| | - Guillem Paniagua Soriano
- Neuronal and Tissue Regeneration Laboratory, Centro de Investigación Príncipe Felipe, 46012 Valencia, Spain
| | - Carlos Sánchez Huertas
- Development and Assembly of Bilateral Neural Circuits Laboratory, Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas (CSIC)-Universidad Miguel Hernández, Avenida Santiago Ramon y Cajal, s/n, 03550 Sant Joan d'Alacant, Alicante, Spain
| | - Eva María Villalba Riquelme
- Biochemistry and Molecular Biology Department, Instituto de Investigación, Desarrollo e Innovación en Biotecnología Sanitaria de Elche-IDiBE, Avenida de la Universidad, s/n, Edificio Torregaitán, 03202 Elche, Alicante, Spain
| | - Eric López Mocholi
- Neuronal and Tissue Regeneration Laboratory, Centro de Investigación Príncipe Felipe, 46012 Valencia, Spain
| | - Beatriz Martínez Rojas
- Neuronal and Tissue Regeneration Laboratory, Centro de Investigación Príncipe Felipe, 46012 Valencia, Spain
| | - Ana Alastrué Agudo
- Neuronal and Tissue Regeneration Laboratory, Centro de Investigación Príncipe Felipe, 46012 Valencia, Spain
| | - Sebastián Dupraz
- Laboratory for Axonal Growth and Regeneration, German Center for Neurodegenerative Diseases (DZNE), 53127 Bonn, Germany
| | - Antonio Vicente Ferrer Montiel
- Biochemistry and Molecular Biology Department, Instituto de Investigación, Desarrollo e Innovación en Biotecnología Sanitaria de Elche-IDiBE, Avenida de la Universidad, s/n, Edificio Torregaitán, 03202 Elche, Alicante, Spain
| | - Victoria Moreno Manzano
- Neuronal and Tissue Regeneration Laboratory, Centro de Investigación Príncipe Felipe, 46012 Valencia, Spain.
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Bi Y, Duan W, Silver J. Collagen I is a critical organizer of scarring and CNS regeneration failure. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.07.592424. [PMID: 38766123 PMCID: PMC11100746 DOI: 10.1101/2024.05.07.592424] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2024]
Abstract
Although axotomized neurons retain the ability to initiate the formation of growth cones and attempt to regenerate after spinal cord injury, the scar area formed as a result of the lesion in most adult mammals contains a variety of reactive cells that elaborate multiple extracellular matrix and enzyme components that are not suitable for regrowth 1,2 . Newly migrating axons in the vicinity of the scar utilize upregulated LAR family receptor protein tyrosine phosphatases, such as PTPσ, to associate with extracellular chondroitin sulphate proteoglycans (CSPGs), which have been discovered to tightly entrap the regrowing axon tip and transform it into a dystrophic non-growing endball. The scar is comprised of two compartments, one in the lesion penumbra, the glial scar, composed of reactive microglia, astrocytes and OPCs; and the other in the lesion epicenter, the fibrotic scar, which is made up of fibroblasts, pericytes, endothelial cells and inflammatory cells. While the fibrotic scar is known to be strongly inhibitory, even more so than the glial scar, the molecular determinants that curtail axon elongation through the injury core are largely uncharacterized. Here, we show that one sole member of the entire family of collagens, collagen I, creates an especially potent inducer of endball formation and regeneration failure. The inhibitory signaling is mediated by mechanosensitive ion channels and RhoA activation. Staggered systemic administration of two blood-brain barrier permeable-FDA approved drugs, aspirin and pirfenidone, reduced fibroblast incursion into the complete lesion and dramatically decreased collagen I, as well as CSPG deposition which were accompanied by axonal growth and considerable functional recovery. The anatomical substrate for robust axonal regeneration was provided by laminin producing GFAP + and NG2 + bridging cells that spanned the wound. Our results reveal a collagen I-mechanotransduction axis that regulates axonal regrowth in spinal cord injury and raise a promising strategy for rapid clinical application.
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Yuan WQ, Huang WP, Jiang YC, Xu H, Duan CS, Chen NH, Liu YJ, Fu XM. The function of astrocytes and their role in neurological diseases. Eur J Neurosci 2023; 58:3932-3961. [PMID: 37831013 DOI: 10.1111/ejn.16160] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 09/11/2023] [Accepted: 09/13/2023] [Indexed: 10/14/2023]
Abstract
Astrocytes have countless links with neurons. Previously, astrocytes were only considered a scaffold of neurons; in fact, astrocytes perform a variety of functions, including providing support for neuronal structures and energy metabolism, offering isolation and protection and influencing the formation, function and elimination of synapses. Because of these functions, astrocytes play an critical role in central nervous system (CNS) diseases. The regulation of the secretiory factors, receptors, channels and pathways of astrocytes can effectively inhibit the occurrence and development of CNS diseases, such as neuromyelitis optica (NMO), multiple sclerosis, Alzheimer's disease (AD), Parkinson's disease (PD) and Huntington's disease. The expression of aquaporin 4 in AS is directly related to NMO and indirectly involved in the clearance of Aβ and tau proteins in AD. Connexin 43 has a bidirectional effect on glutamate diffusion at different stages of stroke. Interestingly, astrocytes reduce the occurrence of PD through multiple effects such as secretion of related factors, mitochondrial autophagy and aquaporin 4. Therefore, this review is focused on the structure and function of astrocytes and the correlation between astrocytes and CNS diseases and drug treatment to explore the new functions of astrocytes with the astrocytes as the target. This, in turn, would provide a reference for the development of new drugs to protect neurons and promote the recovery of nerve function.
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Affiliation(s)
- Wen-Qin Yuan
- College of Pharmacy, Jiangxi University of Chinese Medicine, Nanchang, China
| | - Wei-Peng Huang
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica and Neuroscience Center, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- College of Pharmacy, Minzu University of China, Beijing, China
| | - Yang-Chao Jiang
- College of Pharmacy, Jiangxi University of Chinese Medicine, Nanchang, China
| | - Hao Xu
- College of Economics and Management, Jiangxi University of Chinese Medicine, Nanchang, China
| | - Chong-Shen Duan
- College of Pharmacy, Jiangxi University of Chinese Medicine, Nanchang, China
| | - Nai-Hong Chen
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica and Neuroscience Center, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Ying-Jiao Liu
- College of Pharmacy, Jiangxi University of Chinese Medicine, Nanchang, China
| | - Xiao-Mei Fu
- College of Pharmacy, Jiangxi University of Chinese Medicine, Nanchang, China
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Li L, Zheng H, Ma X, Bai J, Ma S, Li Z, Qin C. Inhibition of Astrocytic Carbohydrate Sulfotransferase 15 Promotes Nerve Repair After Spinal Cord Injury via Mitigation of CSPG Mediated Axonal Inhibition. Cell Mol Neurobiol 2023; 43:2925-2937. [PMID: 36913114 PMCID: PMC11410133 DOI: 10.1007/s10571-023-01333-9] [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: 03/14/2022] [Accepted: 03/01/2023] [Indexed: 03/14/2023]
Abstract
Nerve tissue regeneration is a significant problem. After neural diseases and damage such as spinal cord injury (SCI), the accumulation of chondroitin sulfate proteoglycans (CSPG) comprising axonal inhibitory glycosaminoglycan chains in the microenvironment is a major barrier that obstructs nerve repair. Interfering with the production of glycosaminoglycans, especially the critical inhibitory chains, could be a potential therapeutic strategy for SCI, which is, however, poorly defined. This study identifies Chst15, the chondroitin sulfotransferase controlling the generation of axonal inhibitory chondroitin sulfate-E, as a therapeutic target of SCI. Using a recently reported small molecular Chst15 inhibitor, this study investigates the effects of Chst15 inhibition on astrocyte behaviors and the associated consequences of in vivo disruption of the inhibitory microenvironment. Deposition of CSPGs in the extracellular matrix and migration of astrocytes are both significantly impaired by Chst15 inhibition. Administration of the inhibitor in transected spinal cord tissues of rats effectively promotes motor functional restoration and nerve tissue regeneration by a mechanism related to the attenuation of inhibitory CSPGs, glial scar formation and inflammatory responses. This study highlights the role of Chst15 in the CSPG-mediated inhibition of neural recovery after SCI and proposes an effective neuroregenerative therapeutic strategy that uses Chst15 as a potential target.
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Affiliation(s)
- Liming Li
- Key Laboratory of Marine Drugs, Chinese Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, Qingdao, 266071, China.
- Rehabilitation Sciences and Engineering, University of Health and Rehabilitation Sciences, Qingdao, 266071, China.
| | - Heping Zheng
- Key Laboratory of Marine Drugs, Chinese Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, Qingdao, 266071, China
| | - Xuepei Ma
- Key Laboratory of Marine Drugs, Chinese Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, Qingdao, 266071, China
| | - Jie Bai
- Key Laboratory of Marine Drugs, Chinese Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, Qingdao, 266071, China
| | - Shumin Ma
- Key Laboratory of Marine Drugs, Chinese Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, Qingdao, 266071, China
| | - Zhuoyue Li
- Key Laboratory of Marine Drugs, Chinese Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, Qingdao, 266071, China
| | - Chong Qin
- Key Laboratory of Marine Drugs, Chinese Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, Qingdao, 266071, China.
- Laboratory for Marine Drugs and Bioproducts, Pilot National Laboratory for Marine Science and Technology, Qingdao, 266137, China.
- Center for Targeted Protein Degradation and Drug Discovery, Ocean University of China, Qingdao, 266003, China.
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11
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Shafqat A, Albalkhi I, Magableh HM, Saleh T, Alkattan K, Yaqinuddin A. Tackling the glial scar in spinal cord regeneration: new discoveries and future directions. Front Cell Neurosci 2023; 17:1180825. [PMID: 37293626 PMCID: PMC10244598 DOI: 10.3389/fncel.2023.1180825] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Accepted: 05/08/2023] [Indexed: 06/10/2023] Open
Abstract
Axonal regeneration and functional recovery are poor after spinal cord injury (SCI), typified by the formation of an injury scar. While this scar was traditionally believed to be primarily responsible for axonal regeneration failure, current knowledge takes a more holistic approach that considers the intrinsic growth capacity of axons. Targeting the SCI scar has also not reproducibly yielded nearly the same efficacy in animal models compared to these neuron-directed approaches. These results suggest that the major reason behind central nervous system (CNS) regeneration failure is not the injury scar but a failure to stimulate axon growth adequately. These findings raise questions about whether targeting neuroinflammation and glial scarring still constitute viable translational avenues. We provide a comprehensive review of the dual role of neuroinflammation and scarring after SCI and how future research can produce therapeutic strategies targeting the hurdles to axonal regeneration posed by these processes without compromising neuroprotection.
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12
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Emerson J, Delgado T, Girardi P, Johnson GVW. Deletion of Transglutaminase 2 from Mouse Astrocytes Significantly Improves Their Ability to Promote Neurite Outgrowth on an Inhibitory Matrix. Int J Mol Sci 2023; 24:6058. [PMID: 37047031 PMCID: PMC10094709 DOI: 10.3390/ijms24076058] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 03/01/2023] [Accepted: 03/16/2023] [Indexed: 04/14/2023] Open
Abstract
Astrocytes are the primary support cells of the central nervous system (CNS) that help maintain the energetic requirements and homeostatic environment of neurons. CNS injury causes astrocytes to take on reactive phenotypes with an altered overall function that can range from supportive to harmful for recovering neurons. The characterization of reactive astrocyte populations is a rapidly developing field, and the underlying factors and signaling pathways governing which type of reactive phenotype that astrocytes take on are poorly understood. Our previous studies suggest that transglutaminase 2 (TG2) has an important role in determining the astrocytic response to injury. Selectively deleting TG2 from astrocytes improves functional outcomes after CNS injury and causes widespread changes in gene regulation, which is associated with its nuclear localization. To begin to understand how TG2 impacts astrocytic function, we used a neuron-astrocyte co-culture paradigm to compare the effects of TG2-/- and wild-type (WT) mouse astrocytes on neurite outgrowth and synapse formation. Neurons were grown on a control substrate or an injury-simulating matrix comprised of inhibitory chondroitin sulfate proteoglycans (CSPGs). Compared to WT astrocytes, TG2-/- astrocytes supported neurite outgrowth to a significantly greater extent only on the CSPG matrix, while synapse formation assays showed mixed results depending on the pre- and post-synaptic markers analyzed. We hypothesize that TG2 regulates the supportive functions of astrocytes in injury conditions by modulating gene expression through interactions with transcription factors and transcription complexes. Based on the results of a previous yeast two-hybrid screen for TG2 interactors, we further investigated the interaction of TG2 with Zbtb7a, a ubiquitously expressed transcription factor. Co-immunoprecipitation and colocalization analyses confirmed the interaction of TG2 and Zbtb7a in the nucleus of astrocytes. Overexpression or knockdown of Zbtb7a levels in WT and TG2-/- astrocytes revealed that Zbtb7a robustly influenced astrocytic morphology and the ability of astrocytes to support neuronal outgrowth, which was significantly modulated by the presence of TG2. These findings support our hypothesis that astrocytic TG2 acts as a transcriptional regulator to influence astrocytic function, with greater influence under injury conditions that increase its expression, and Zbtb7a likely contributes to the overall effects observed with astrocytic TG2 deletion.
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Affiliation(s)
| | | | - Peter Girardi
- Department of Anesthesiology and Perioperative Medicine, University of Rochester, 601 Elmwood Ave., Box 604, Rochester, NY 14620, USA
| | - Gail V. W. Johnson
- Department of Anesthesiology and Perioperative Medicine, University of Rochester, 601 Elmwood Ave., Box 604, Rochester, NY 14620, USA
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13
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Petrosyan HA, Alessi V, Lasek K, Gumudavelli S, Muffaletto R, Liang L, Collins WF, Levine J, Arvanian VL. AAV Vector Mediated Delivery of NG2 Function Neutralizing Antibody and Neurotrophin NT-3 Improves Synaptic Transmission, Locomotion, and Urinary Tract Function after Spinal Cord Contusion Injury in Adult Rats. J Neurosci 2023; 43:1492-1508. [PMID: 36653191 PMCID: PMC10008066 DOI: 10.1523/jneurosci.1276-22.2023] [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: 06/28/2022] [Revised: 01/06/2023] [Accepted: 01/10/2023] [Indexed: 01/20/2023] Open
Abstract
NG2 is a structurally unique transmembrane chondroitin sulfate proteoglycan (CSPG). Its role in damaged spinal cord is dual. NG2 is considered one of key inhibitory factors restricting axonal growth following spinal injury. Additionally, we have recently detected its novel function as a blocker of axonal conduction. Some studies, however, indicate the importance of NG2 presence in the formation of synaptic contacts. We hypothesized that the optimal treatment would be neutralization of inhibitory functions of NG2 without its physical removal. Acute intraspinal injections of anti-NG2 monoclonal antibodies reportedly prevented an acute block of axonal conduction by exogenous NG2. For prolonged delivery of NG2 function neutralizing antibody, we have developed a novel gene therapy: adeno-associated vector (AAV) construct expressing recombinant single-chain variable fragment anti-NG2 antibody (AAV-NG2Ab). We examined effects of AAV-NG2Ab alone or in combination with neurotrophin NT-3 in adult female rats with thoracic T10 contusion injuries. A battery of behavioral tests was used to evaluate locomotor function. In vivo single-cell electrophysiology was used to evaluate synaptic transmission. Lower urinary tract function was assessed during the survival period using metabolic chambers. Terminal cystometry, with acquisition of external urethral sphincter activity and bladder pressure, was used to evaluate bladder function. Both the AAV-NG2Ab and AAV-NG2Ab combined with AAV-NT3 treatment groups demonstrated significant improvements in transmission, locomotion, and bladder function compared with the control (AAV-GFP) group. These functional improvements associated with improved remyelination and plasticity of 5-HT fibers. The best results were observed in the group that received combinational AAV-NG2Ab+AAV-NT3 treatment.SIGNIFICANCE STATEMENT We recently demonstrated beneficial, but transient, effects of neutralization of the NG2 proteoglycan using monoclonal antibodies delivered intrathecally via osmotic mini-pumps after spinal cord injury. Currently, we have developed a novel gene therapy tool for prolonged and clinically relevant delivery of a recombinant single-chain variable fragment anti-NG2 antibody: AAV-rh10 serotype expressing scFv-NG2 (AAV-NG2Ab). Here, we examined effects of AAV-NG2Ab combined with transgene delivery of Neurotrophin-3 (AAV-NT3) in adult rats with thoracic contusion injuries. The AAV-NG2Ab and AAV-NG2Ab+AAV-NT3 treatment groups demonstrated significant improvements of locomotor function and lower urinary tract function. Beneficial effects of this novel gene therapy on locomotion and bladder function associated with improved transmission to motoneurons and plasticity of axons in damaged spinal cord.
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Affiliation(s)
- Hayk A Petrosyan
- Northport Veterans Affairs Medical Center, Northport, New York 11768
- Department of Neurobiology and Behavior, Stony Brook University, Stony Brook, New York 11794
| | - Valentina Alessi
- Northport Veterans Affairs Medical Center, Northport, New York 11768
- Department of Neurobiology and Behavior, Stony Brook University, Stony Brook, New York 11794
| | - Kristin Lasek
- Northport Veterans Affairs Medical Center, Northport, New York 11768
- Department of Neurobiology and Behavior, Stony Brook University, Stony Brook, New York 11794
| | - Sricharan Gumudavelli
- Department of Neurobiology and Behavior, Stony Brook University, Stony Brook, New York 11794
| | - Robert Muffaletto
- Department of Neurobiology and Behavior, Stony Brook University, Stony Brook, New York 11794
| | - Li Liang
- Northport Veterans Affairs Medical Center, Northport, New York 11768
| | - William F Collins
- Department of Neurobiology and Behavior, Stony Brook University, Stony Brook, New York 11794
| | - Joel Levine
- Department of Neurobiology and Behavior, Stony Brook University, Stony Brook, New York 11794
| | - Victor L Arvanian
- Northport Veterans Affairs Medical Center, Northport, New York 11768
- Department of Neurobiology and Behavior, Stony Brook University, Stony Brook, New York 11794
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14
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Shi M, Xu Q, Ding L, Xia Y, Zhang C, Lai H, Liu C, Deng DYB. Cell Infiltrative Inner Connected Porous Hydrogel Improves Neural Stem Cell Migration and Differentiation for Functional Repair of Spinal Cord Injury. ACS Biomater Sci Eng 2022; 8:5307-5318. [PMID: 36455201 DOI: 10.1021/acsbiomaterials.2c01127] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
The disadvantages of cell-adaptive microenvironments and cellular diffusion out of the lesion have limited hydrogel-based scaffold transplantation treatment for neural connectivity, leading to permanent neurological disability from spinal cord injury. Herein, porous GelMA scaffold was prepared, in which the inner porous structure was optimized. The average pore size was 168 ± 71 μm with a porosity of 77.1%. The modulus of porous hydrogel was 593 ± 4 Pa compared to 1535 ± 85 Pa of bulk GelMA. The inner connected porous structure provided a cell-infiltrative matrix for neural stem cell migration and differentiation in vitro and eventually enhanced neuron differentiation and hindlimb strength and movement of animals in in vivo experiments. Furthermore, inflammation response and apoptosis were also alleviated after implantation. This work demonstrated that the porous hydrogel with appropriately connected micropores exhibit favorable cellular responses compared with traditional non-porous GelMA hydrogel. Taken together, our findings suggest that porous hydrogel is a promising scaffold for future delivery of stem cells and has prospects in material design for the treatment of spinal cord injury.
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Affiliation(s)
- Ming Shi
- Department of Scientific Research Center, The Seventh Affiliated Hospital of Sun Yat-sen University, Shenzhen518107, China
| | - Qi Xu
- Department of Scientific Research Center, The Seventh Affiliated Hospital of Sun Yat-sen University, Shenzhen518107, China
| | - Lu Ding
- Department of Scientific Research Center, The Seventh Affiliated Hospital of Sun Yat-sen University, Shenzhen518107, China
| | - Yu Xia
- Department of Scientific Research Center, The Seventh Affiliated Hospital of Sun Yat-sen University, Shenzhen518107, China
| | - Changlin Zhang
- Department of Gynecology, The Seventh Affiliated Hospital of Sun Yat-sen University, Shenzhen518107, China.,Pelvic Floor Disorders Center, The Seventh Affiliated Hospital of Sun Yat-sen University, Shenzhen518107, China
| | - Haibin Lai
- Department of Scientific Research Center, The Seventh Affiliated Hospital of Sun Yat-sen University, Shenzhen518107, China
| | - Changxuan Liu
- Department of Scientific Research Center, The Seventh Affiliated Hospital of Sun Yat-sen University, Shenzhen518107, China
| | - David Y B Deng
- Department of Scientific Research Center, The Seventh Affiliated Hospital of Sun Yat-sen University, Shenzhen518107, China
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15
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Han N, Wen Y, Liu Z, Zhai J, Li S, Yin J. Advances in the roles and mechanisms of lignans against Alzheimer’s disease. Front Pharmacol 2022; 13:960112. [PMID: 36313287 PMCID: PMC9596774 DOI: 10.3389/fphar.2022.960112] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Accepted: 08/24/2022] [Indexed: 11/30/2022] Open
Abstract
Background: Alzheimer’s disease (AD) is a serious neurodegenerative disease associated with the memory and cognitive impairment. The occurrence of AD is due to the accumulation of amyloid β-protein (Aβ) plaques and neurofibrillary tangles (NFTs) in the brain tissue as well as the hyperphosphorylation of Tau protein in neurons, doing harm to the human health and even leading people to death. The development of neuroprotective drugs with small side effects and good efficacy is focused by scientists all over the world. Natural drugs extracted from herbs or plants have become the preferred resources for new candidate drugs. Lignans were reported to effectively protect nerve cells and alleviate memory impairment, suggesting that they might be a prosperous class of compounds in treating AD. Objective: To explore the roles and mechanisms of lignans in the treatment of neurological diseases, providing proofs for the development of lignans as novel anti-AD drugs. Methods: Relevant literature was extracted and retrieved from the databases including China National Knowledge Infrastructure (CNKI), Elsevier, Science Direct, PubMed, SpringerLink, and Web of Science, taking lignan, anti-inflammatory, antioxidant, apoptosis, nerve regeneration, nerve protection as keywords. The functions and mechanisms of lignans against AD were summerized. Results: Lignans were found to have the effects of regulating vascular disorders, anti-infection, anti-inflammation, anti-oxidation, anti-apoptosis, antagonizing NMDA receptor, suppressing AChE activity, improving gut microbiota, so as to strengthening nerve protection. Among them, dibenzocyclooctene lignans were most widely reported and might be the most prosperous category in the develpment of anti-AD drugs. Conclusion: Lignans displayed versatile roles and mechanisms in preventing the progression of AD in in vitro and in vivo models, supplying potential candidates for the treatment of nerrodegenerative diseases.
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16
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Siddiqui N, Oshima K, Hippensteel JA. Proteoglycans and Glycosaminoglycans in Central Nervous System Injury. Am J Physiol Cell Physiol 2022; 323:C46-C55. [PMID: 35613357 PMCID: PMC9273265 DOI: 10.1152/ajpcell.00053.2022] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The brain and spinal cord constitute the central nervous system (CNS), which when injured, can be exceedingly devastating. The mechanistic roles of proteoglycans (PGs) and their glycosaminoglycan (GAG) side chains in such injuries have been extensively studied. CNS injury immediately alters endothelial and extracellular matrix (ECM) PGs and GAGs. Subsequently, these alterations contribute to acute injury, post-injury fibrosis, and post-injury repair. These effects are central to the pathophysiology of CNS injury. This review focuses on the importance of PGs and GAGs in multiple forms of injury including traumatic brain injury, spinal cord injury, and stroke. We highlight the causes and consequences of degradation of the PG and GAG-enriched endothelial glycocalyx in early injury and discuss the pleiotropic roles of PGs in neuroinflammation. We subsequently evaluate the dualistic effects of PGs on recovery: both PG/GAG-mediated inhibition and facilitation of repair. We then report promising therapeutic strategies that may prove effective for repair of CNS injury including PG receptor inhibition, delivery of endogenous, pro-repair PGs and GAGs, and direct degradation of pathologic GAGs. Last, we discuss importance of two PG- and GAG-containing ECM structures (synapses and perineuronal nets) in CNS injury and recovery.
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Affiliation(s)
- Noah Siddiqui
- Division of Pulmonary Sciences and Critical Care Medicine, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States
| | - Kaori Oshima
- Division of Pulmonary Sciences and Critical Care Medicine, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States
| | - Joseph A Hippensteel
- Division of Pulmonary Sciences and Critical Care Medicine, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States
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17
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Cooke P, Janowitz H, Dougherty SE. Neuronal Redevelopment and the Regeneration of Neuromodulatory Axons in the Adult Mammalian Central Nervous System. Front Cell Neurosci 2022; 16:872501. [PMID: 35530177 PMCID: PMC9074815 DOI: 10.3389/fncel.2022.872501] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Accepted: 03/24/2022] [Indexed: 01/09/2023] Open
Abstract
One reason that many central nervous system injuries, including those arising from traumatic brain injury, spinal cord injury, and stroke, have limited recovery of function is that neurons within the adult mammalian CNS lack the ability to regenerate their axons following trauma. This stands in contrast to neurons of the adult mammalian peripheral nervous system (PNS). New evidence, provided by single-cell expression profiling, suggests that, following injury, both mammalian central and peripheral neurons can revert to an embryonic-like growth state which is permissive for axon regeneration. This “redevelopment” strategy could both facilitate a damage response necessary to isolate and repair the acute damage from injury and provide the intracellular machinery necessary for axon regrowth. Interestingly, serotonin neurons of the rostral group of raphe nuclei, which project their axons into the forebrain, display a robust ability to regenerate their axons unaided, counter to the widely held view that CNS axons cannot regenerate without experimental intervention after injury. Furthermore, initial evidence suggests that norepinephrine neurons within the locus coeruleus possess similar regenerative abilities. Several morphological characteristics of serotonin axon regeneration in adult mammals, observable using longitudinal in vivo imaging, are distinct from the known characteristics of unaided peripheral nerve regeneration, or of the regeneration seen in the spinal cord and optic nerve that occurs with experimental intervention. These results suggest that there is an alternative CNS program for axon regeneration that likely differs from that displayed by the PNS.
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Affiliation(s)
- Patrick Cooke
- Linden Lab, Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Haley Janowitz
- Linden Lab, Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Sarah E Dougherty
- Linden Lab, Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, United States
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18
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The Role of Tissue Geometry in Spinal Cord Regeneration. MEDICINA (KAUNAS, LITHUANIA) 2022; 58:medicina58040542. [PMID: 35454380 PMCID: PMC9028021 DOI: 10.3390/medicina58040542] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Accepted: 04/11/2022] [Indexed: 11/17/2022]
Abstract
Unlike peripheral nerves, axonal regeneration is limited following injury to the spinal cord. While there may be reduced regenerative potential of injured neurons, the central nervous system (CNS) white matter environment appears to be more significant in limiting regrowth. Several factors may inhibit regeneration, and their neutralization can modestly enhance regrowth. However, most investigations have not considered the cytoarchitecture of spinal cord white matter. Several lines of investigation demonstrate that axonal regeneration is enhanced by maintaining, repairing, or reconstituting the parallel geometry of the spinal cord white matter. In this review, we focus on environmental factors that have been implicated as putative inhibitors of axonal regeneration and the evidence that their organization may be an important determinant in whether they inhibit or promote regeneration. Consideration of tissue geometry may be important for developing successful strategies to promote spinal cord regeneration.
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19
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Slater PG, Domínguez-Romero ME, Villarreal M, Eisner V, Larraín J. Mitochondrial function in spinal cord injury and regeneration. Cell Mol Life Sci 2022; 79:239. [PMID: 35416520 PMCID: PMC11072423 DOI: 10.1007/s00018-022-04261-x] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Revised: 03/16/2022] [Accepted: 03/17/2022] [Indexed: 12/21/2022]
Abstract
Many people around the world suffer from some form of paralysis caused by spinal cord injury (SCI), which has an impact on quality and life expectancy. The spinal cord is part of the central nervous system (CNS), which in mammals is unable to regenerate, and to date, there is a lack of full functional recovery therapies for SCI. These injuries start with a rapid and mechanical insult, followed by a secondary phase leading progressively to greater damage. This secondary phase can be potentially modifiable through targeted therapies. The growing literature, derived from mammalian and regenerative model studies, supports a leading role for mitochondria in every cellular response after SCI: mitochondrial dysfunction is the common event of different triggers leading to cell death, cellular metabolism regulates the immune response, mitochondrial number and localization correlate with axon regenerative capacity, while mitochondrial abundance and substrate utilization regulate neural stem progenitor cells self-renewal and differentiation. Herein, we present a comprehensive review of the cellular responses during the secondary phase of SCI, the mitochondrial contribution to each of them, as well as evidence of mitochondrial involvement in spinal cord regeneration, suggesting that a more in-depth study of mitochondrial function and regulation is needed to identify potential targets for SCI therapeutic intervention.
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Affiliation(s)
- Paula G Slater
- Center for Aging and Regeneration, Departamento de Biología Celular Y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Alameda 340, 8331150, Santiago, Chile.
| | - Miguel E Domínguez-Romero
- Center for Aging and Regeneration, Departamento de Biología Celular Y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Alameda 340, 8331150, Santiago, Chile
| | - Maximiliano Villarreal
- Center for Aging and Regeneration, Departamento de Biología Celular Y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Alameda 340, 8331150, Santiago, Chile
| | - Verónica Eisner
- Center for Aging and Regeneration, Departamento de Biología Celular Y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Alameda 340, 8331150, Santiago, Chile
- Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Alameda 340, 8331150, Santiago, Chile
| | - Juan Larraín
- Center for Aging and Regeneration, Departamento de Biología Celular Y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Alameda 340, 8331150, Santiago, Chile
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20
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Crapser JD, Arreola MA, Tsourmas KI, Green KN. Microglia as hackers of the matrix: sculpting synapses and the extracellular space. Cell Mol Immunol 2021; 18:2472-2488. [PMID: 34413489 PMCID: PMC8546068 DOI: 10.1038/s41423-021-00751-3] [Citation(s) in RCA: 83] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 07/26/2021] [Indexed: 02/08/2023] Open
Abstract
Microglia shape the synaptic environment in health and disease, but synapses do not exist in a vacuum. Instead, pre- and postsynaptic terminals are surrounded by extracellular matrix (ECM), which together with glia comprise the four elements of the contemporary tetrapartite synapse model. While research in this area is still just beginning, accumulating evidence points toward a novel role for microglia in regulating the ECM during normal brain homeostasis, and such processes may, in turn, become dysfunctional in disease. As it relates to synapses, microglia are reported to modify the perisynaptic matrix, which is the diffuse matrix that surrounds dendritic and axonal terminals, as well as perineuronal nets (PNNs), specialized reticular formations of compact ECM that enwrap neuronal subsets and stabilize proximal synapses. The interconnected relationship between synapses and the ECM in which they are embedded suggests that alterations in one structure necessarily affect the dynamics of the other, and microglia may need to sculpt the matrix to modify the synapses within. Here, we provide an overview of the microglial regulation of synapses, perisynaptic matrix, and PNNs, propose candidate mechanisms by which these structures may be modified, and present the implications of such modifications in normal brain homeostasis and in disease.
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Affiliation(s)
- Joshua D. Crapser
- grid.266093.80000 0001 0668 7243Department of Neurobiology and Behavior, University of California, Irvine, CA USA
| | - Miguel A. Arreola
- grid.266093.80000 0001 0668 7243Department of Neurobiology and Behavior, University of California, Irvine, CA USA
| | - Kate I. Tsourmas
- grid.266093.80000 0001 0668 7243Department of Neurobiology and Behavior, University of California, Irvine, CA USA
| | - Kim N. Green
- grid.266093.80000 0001 0668 7243Department of Neurobiology and Behavior, University of California, Irvine, CA USA
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21
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Mu J, Wu J, Cao J, Ma T, Li L, Feng S, Gao J. Rapid and effective treatment of traumatic spinal cord injury using stem cell derived exosomes. Asian J Pharm Sci 2021; 16:806-815. [PMID: 35027955 PMCID: PMC8739259 DOI: 10.1016/j.ajps.2021.10.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2021] [Revised: 10/21/2021] [Accepted: 10/21/2021] [Indexed: 02/08/2023] Open
Abstract
Traumatic spinal cord injury is a fatal acute event without effective clinical therapies. Following the trauma, immediate neural protection and microenvironment mitigation are vitally important for nerve tissue repair, where stem cell-based therapies could be eclipsed by the deficiency of cells due to the hostile microenvironment as well as the transport and preservation processes. Effective emergency strategies are required to be convenient, biocompatible, and stable. Herein, we assess an emergency cell-free treatment using mesenchymal stem cell-derived exosomes, which have proven capable of comprehensive mitigation of the inhibitory lesion microenvironment. The clinically validated fibrin glue is utilized to encapsulate the exosomes and in-situ gelates in transected rat spinal cords to provide a substrate for exosome delivery as well as nerve tissue growth. The emergency treatment alleviates the inflammatory and oxidative microenvironment, inducing effective nerve tissue repair and functional recovery. The therapy presents a promising strategy for effective emergency treatment of central nervous system trauma.
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22
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Du YL, Sergeeva EG, Stein DG. Visual recovery following optic nerve crush in male and female wild-type and TRIF-deficient mice. Restor Neurol Neurosci 2021; 38:355-368. [PMID: 32986632 DOI: 10.3233/rnn-201019] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND There is growing evidence that the TIR-domain-containing adapter-inducing interferon-β (TRIF) pathway is implicated in the modulation of neuroinflammation following injuries to the brain and retina. After exposure to injury or to excitotoxic pathogens, toll-like receptors (TLR) activate the innate immune system signaling cascade and stimulate the release of inflammatory cytokines. Inhibition of the TLR4 receptor has been shown to enhance retinal ganglion cell (RGC) survival in optic nerve crush (ONC) and in ischemic injury to other parts of the brain. OBJECTIVE Based on this evidence, we tested the hypothesis that mice with the TRIF gene knocked out (TKO) will demonstrate decreased inflammatory responses and greater functional recovery after ONC. METHODS Four experimental groups -TKO ONC (12 males and 8 females), WT ONC (10 males and 8 females), TKO sham (9 males and 5 females), and WT sham (7 males and 5 females) -were used as subjects. Visual evoked potentials (VEP) were recorded in the left and right primary visual cortices and optomotor response were assessed in all mice at 14, 30, and 80 days after ONC. GFAP and Iba-1 were used as markers for astrocytes and microglial cells respectively at 7 days after ONC, along with NF-kB to measure inflammatory effects downstream of TRIF activation; RMPBS marker was used to visualize RGC survival and GAP-43 was used as a marker of regenerating optic nerve axons at 30 days after ONC. RESULTS We found reduced inflammatory response in the retina at 7 days post-ONC, less RGC loss and greater axonal regeneration 30 days post-ONC, and better recovery of visual function 80 days post-ONC in TKO mice compared to WT mice. CONCLUSIONS Our study showed that the TRIF pathway is involved in post-ONC inflammatory response and gliosis and that deletion of TRIF induces better RGC survival and regeneration and better functional recovery in mice. Our results suggest the TRIF pathway as a potential therapeutic target for reducing the inflammatory damage caused by nervous system injury.
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Affiliation(s)
- Yimeng Lina Du
- Emory University College of Arts and Sciences, Neuroscience and Behavioral Biology Program, GA, USA
| | - Elena G Sergeeva
- Department of Emergency Medicine, Emory University School of Medicine, Atlanta, GA, USA
| | - Donald G Stein
- Emory University College of Arts and Sciences, Neuroscience and Behavioral Biology Program, GA, USA.,Department of Emergency Medicine, Emory University School of Medicine, Atlanta, GA, USA
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23
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Lipocalin 2 as a Putative Modulator of Local Inflammatory Processes in the Spinal Cord and Component of Organ Cross talk After Spinal Cord Injury. Mol Neurobiol 2021; 58:5907-5919. [PMID: 34417948 DOI: 10.1007/s12035-021-02530-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Accepted: 08/09/2021] [Indexed: 10/20/2022]
Abstract
Lipocalin 2 (LCN2), an immunomodulator, regulates various cellular processes such as iron transport and defense against bacterial infection. Under pathological conditions, LCN2 promotes neuroinflammation via the recruitment and activation of immune cells and glia, particularly microglia and astrocytes. Although it seems to have a negative influence on the functional outcome in spinal cord injury (SCI), the extent of its involvement in SCI and the underlying mechanisms are not yet fully known. In this study, using a SCI contusion mouse model, we first investigated the expression pattern of Lcn2 in different parts of the CNS (spinal cord and brain) and in the liver and its concentration in blood serum. Interestingly, we could note a significant increase in LCN2 throughout the whole spinal cord, in the brain, liver, and blood serum. This demonstrates the diversity of its possible sites of action in SCI. Furthermore, genetic deficiency of Lcn2 (Lcn2-/-) significantly reduced certain aspects of gliosis in the SCI-mice. Taken together, our studies provide first valuable hints, suggesting that LCN2 is involved in the local and systemic effects post SCI, and might modulate the impairment of different peripheral organs after injury.
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24
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Miyagi M, Uchida K, Takano S, Nakawaki M, Sekiguchi H, Nakazawa T, Imura T, Saito W, Shirasawa E, Kawakubo A, Akazawa T, Inoue G, Takaso M. Role of CD14-positive cells in inflammatory cytokine and pain-related molecule expression in human degenerated intervertebral discs. J Orthop Res 2021; 39:1755-1762. [PMID: 32856747 DOI: 10.1002/jor.24839] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 07/13/2020] [Accepted: 08/18/2020] [Indexed: 02/04/2023]
Abstract
Multiple human and animal studies suggest that the upregulation of inflammatory cytokines and other pain-related molecules in degenerated or injured intervertebral discs (IVDs) may cause discogenic low back pain (LBP). We previously reported that macrophages in injured IVD in mice produced inflammatory cytokines, but not other pain-related molecules. CD14 is a monocyte marker expressed mainly by macrophages. The aim of the current study was to evaluate the role of CD14-positive cells in inflammatory cytokine and pain-related molecule expression in human degenerated IVD. IVD samples were harvested from 14 patients, including 10 with lumbar spinal stenosis, four with adult spinal deformity, and one with lumbar disc herniation during spinal interbody fusion surgery. Harvested IVD-derived mononuclear cells were obtained and CD14-positive (+) and CD14-negative (-) cells were separated using CD14 antibody and streptavidin-labeled magnetic beads. Inflammatory cytokines messenger RNA (mRNA) in the CD14(+) and CD14(-) cells, including tumor necrosis factor ɑ (TNFA), in, terleukin-1β (IL1B) and IL6, were determined using quantitative polymerase chain reaction (qPCR) and their expression levels were compared. To evaluate factors controlling the regulation of pain-related molecules mRNA expression, cultured CD14(-) and CD14(+) cells from IVDs were stimulated with recombinant human TNF-ɑ and IL-1β and levels of pain-related molecules, including calcitonin gene-related peptide (CGRP) and nerve growth factor (NGF) were determined using qPCR. Levels of TNFA, IL1B, IL6, and NGF in CD14(+) cells were significantly increased compared with those in CD14(-) cells (TNFA, p = 0.006; IL1B, p = .017; IL6, p = .010; NGF, p = .027). Following TNFA stimulation, NGF levels were significantly increased in CD14(-) and CD14(+) cells (CD14(-), p = .003; CD14(+), p < .001) and CGRP was significantly increased in CD14(-) IVD cells (p = .040). Following IL1B stimulation, NGF levels were significantly increased in CD14(-) cells (p = .004). CD14(+) cells had higher TNFA, IL1B, IL6, and NGF expressions than CD14(-) cells in human degenerated IVDs. Additionally, TNFA stimulation promoted the upregulation of NGF and CGRP in CD14(-) cells. These findings suggested that CD14(+) cells directly and indirectly contributed to inflammatory cytokine and pain-related molecule expression in human degenerated IVD. CD14(+) cells might be important in the pathological mechanism of chronic discogenic LBP in humans.
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Affiliation(s)
- Masayuki Miyagi
- Department of Orthopedic Surgery, Kitasato University School of Medicine, Sagamihara City, Kanagawa, Japan
| | - Kentaro Uchida
- Department of Orthopedic Surgery, Kitasato University School of Medicine, Sagamihara City, Kanagawa, Japan
| | - Shotaro Takano
- Department of Orthopedic Surgery, Kitasato University School of Medicine, Sagamihara City, Kanagawa, Japan
| | - Mitsufumi Nakawaki
- Department of Orthopedic Surgery, Kitasato University School of Medicine, Sagamihara City, Kanagawa, Japan
| | - Hiroyuki Sekiguchi
- Shonan University of Medical Sciences Research Institute, Chigasaki City, Kanagawa, Japan
| | - Toshiyuki Nakazawa
- Department of Orthopedic Surgery, Kitasato University School of Medicine, Sagamihara City, Kanagawa, Japan
| | - Takayuki Imura
- Department of Orthopedic Surgery, Kitasato University School of Medicine, Sagamihara City, Kanagawa, Japan
| | - Wataru Saito
- Department of Orthopedic Surgery, Kitasato University School of Medicine, Sagamihara City, Kanagawa, Japan
| | - Eiki Shirasawa
- Department of Orthopedic Surgery, Kitasato University School of Medicine, Sagamihara City, Kanagawa, Japan
| | - Ayumu Kawakubo
- Department of Orthopedic Surgery, Kitasato University School of Medicine, Sagamihara City, Kanagawa, Japan
| | - Tsutomu Akazawa
- Department of Orthopaedic Surgery, St. Marianna University School of Medicine, Kawasaki City, Kanagawa, Japan
| | - Gen Inoue
- Department of Orthopedic Surgery, Kitasato University School of Medicine, Sagamihara City, Kanagawa, Japan
| | - Masashi Takaso
- Department of Orthopedic Surgery, Kitasato University School of Medicine, Sagamihara City, Kanagawa, Japan
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25
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Tran AP, Warren PM, Silver J. New insights into glial scar formation after spinal cord injury. Cell Tissue Res 2021; 387:319-336. [PMID: 34076775 PMCID: PMC8975767 DOI: 10.1007/s00441-021-03477-w] [Citation(s) in RCA: 88] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Accepted: 05/20/2021] [Indexed: 02/06/2023]
Abstract
Severe spinal cord injury causes permanent loss of function and sensation throughout the body. The trauma causes a multifaceted torrent of pathophysiological processes which ultimately act to form a complex structure, permanently remodeling the cellular architecture and extracellular matrix. This structure is traditionally termed the glial/fibrotic scar. Similar cellular formations occur following stroke, infection, and neurodegenerative diseases of the central nervous system (CNS) signifying their fundamental importance to preservation of function. It is increasingly recognized that the scar performs multiple roles affecting recovery following traumatic injury. Innovative research into the properties of this structure is imperative to the development of treatment strategies to recover motor function and sensation following CNS trauma. In this review, we summarize how the regeneration potential of the CNS alters across phyla and age through formation of scar-like structures. We describe how new insights from next-generation sequencing technologies have yielded a more complex portrait of the molecular mechanisms governing the astrocyte, microglial, and neuronal responses to injury and development, especially of the glial component of the scar. Finally, we discuss possible combinatorial therapeutic approaches centering on scar modulation to restore function after severe CNS injury.
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Affiliation(s)
- Amanda Phuong Tran
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, USA
| | - Philippa Mary Warren
- Wolfson Centre for Age Related Diseases, Institute of Psychiatry, Psychology and Neuroscience, King's College London, Guy's Campus, London Bridge, London, UK
| | - Jerry Silver
- Department of Neurosciences, Case Western Reserve University, Cleveland, OH, USA.
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26
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Anderson MA. Targeting Central Nervous System Regeneration with Cell Type Specificity. Neurosurg Clin N Am 2021; 32:397-405. [PMID: 34053727 DOI: 10.1016/j.nec.2021.03.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
There have been tremendous advances in identifying cellular and molecular mechanisms constraining axon growth and strategies have been developed to overcome regenerative failure. However, reproducible and meaningful functional recovery remains elusive. An emerging reason is that neurons possess subtype-specific activation requirements. Much of this evidence comes from studying retinal ganglion cells following optic nerve injury. This review summarizes key neuropathologic events following spinal cord injury, and draws on findings from the optic nerve to suggest how a similar framework may be used to dissect and manipulate the heterogeneous and subtype-specific responses of neurons useful to target for spinal cord injury.
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Affiliation(s)
- Mark A Anderson
- Brain Mind Institute, Faculty of Life Sciences, École Polytechnique Féderale de Lausanne (EPFL), Lausanne, Switzerland; Neural Repair Unit, NeuroRestore, Department of Clinical Neuroscience, Lausanne University Hospital (CHUV) and University of Lausanne (UNIL), Lausanne, Switzerland.
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27
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Astrocyte-immune cell interactions in physiology and pathology. Immunity 2021; 54:211-224. [DOI: 10.1016/j.immuni.2021.01.013] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Revised: 09/29/2020] [Accepted: 01/15/2021] [Indexed: 12/23/2022]
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28
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Agbaegbu Iweka C, Hussein RK, Yu P, Katagiri Y, Geller HM. The lipid phosphatase-like protein PLPPR1 associates with RhoGDI1 to modulate RhoA activation in response to axon growth inhibitory molecules. J Neurochem 2021; 157:494-507. [PMID: 33320336 DOI: 10.1111/jnc.15271] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 12/06/2020] [Accepted: 12/08/2020] [Indexed: 11/29/2022]
Abstract
Phospholipid Phosphatase-Related Protein Type 1 (PLPPR1) is a member of a family of lipid phosphatase related proteins, integral membrane proteins characterized by six transmembrane domains. This family of proteins is enriched in the brain and recent data indicate potential pleiotropic functions in several different contexts. An inherent ability of this family of proteins is to induce morphological changes, and we have previously reported that members of this family interact with each other and may function co-operatively. However, the function of PLPPR1 is not yet understood. Here we show that the expression of PLPPR1 reduces the inhibition of neurite outgrowth of cultured mouse hippocampal neurons by chondroitin sulfate proteoglycans and the retraction of neurites of Neuro-2a cells by lysophosphatidic acid (LPA). Further, we show that PLPPR1 reduces the activation of Ras homolog family member A (RhoA) by LPA in Neuro-2a cells, and that this is because of an association of PLPPR1with the Rho-specific guanine nucleotide dissociation inhibitor (RhoGDI1). These results establish a novel signaling pathway for the PLPPR1 protein.
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Affiliation(s)
- Chinyere Agbaegbu Iweka
- Laboratory of Developmental Neurobiology, National Heart Lung and Blood Institute, NIH, Bethesda, MD, USA.,Department of Neuroscience, Interdisciplinary Program in Neuroscience, Georgetown University, Washington, DC, USA
| | - Rowan K Hussein
- Laboratory of Developmental Neurobiology, National Heart Lung and Blood Institute, NIH, Bethesda, MD, USA
| | - Panpan Yu
- Guangdong-Hongkong-Macau Institute of CNS Regeneration, Jinan University, Guangzhou, China
| | - Yasuhiro Katagiri
- Laboratory of Developmental Neurobiology, National Heart Lung and Blood Institute, NIH, Bethesda, MD, USA
| | - Herbert M Geller
- Laboratory of Developmental Neurobiology, National Heart Lung and Blood Institute, NIH, Bethesda, MD, USA
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29
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Wu D, Jin Y, Shapiro TM, Hinduja A, Baas PW, Tom VJ. Chronic neuronal activation increases dynamic microtubules to enhance functional axon regeneration after dorsal root crush injury. Nat Commun 2020; 11:6131. [PMID: 33257677 PMCID: PMC7705672 DOI: 10.1038/s41467-020-19914-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Accepted: 11/05/2020] [Indexed: 12/26/2022] Open
Abstract
After a dorsal root crush injury, centrally-projecting sensory axons fail to regenerate across the dorsal root entry zone (DREZ) to extend into the spinal cord. We find that chemogenetic activation of adult dorsal root ganglion (DRG) neurons improves axon growth on an in vitro model of the inhibitory environment after injury. Moreover, repeated bouts of daily chemogenetic activation of adult DRG neurons for 12 weeks post-crush in vivo enhances axon regeneration across a chondroitinase-digested DREZ into spinal gray matter, where the regenerating axons form functional synapses and mediate behavioral recovery in a sensorimotor task. Neuronal activation-mediated axon extension is dependent upon changes in the status of tubulin post-translational modifications indicative of highly dynamic microtubules (as opposed to stable microtubules) within the distal axon, illuminating a novel mechanism underlying stimulation-mediated axon growth. We have identified an effective combinatory strategy to promote functionally-relevant axon regeneration of adult neurons into the CNS after injury.
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Affiliation(s)
- Di Wu
- Department of Neurobiology and Anatomy, Marion Murray Spinal Cord Research Center, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Ying Jin
- Department of Neurobiology and Anatomy, Marion Murray Spinal Cord Research Center, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Tatiana M Shapiro
- Department of Neurobiology and Anatomy, Marion Murray Spinal Cord Research Center, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Abhishek Hinduja
- Department of Neurobiology and Anatomy, Marion Murray Spinal Cord Research Center, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Peter W Baas
- Department of Neurobiology and Anatomy, Marion Murray Spinal Cord Research Center, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Veronica J Tom
- Department of Neurobiology and Anatomy, Marion Murray Spinal Cord Research Center, Drexel University College of Medicine, Philadelphia, PA, USA.
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30
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Gottipati MK, D'Amato AR, Ziemba AM, Popovich PG, Gilbert RJ. TGFβ3 is neuroprotective and alleviates the neurotoxic response induced by aligned poly-l-lactic acid fibers on naïve and activated primary astrocytes. Acta Biomater 2020; 117:273-282. [PMID: 33035696 DOI: 10.1016/j.actbio.2020.09.057] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Revised: 09/24/2020] [Accepted: 09/29/2020] [Indexed: 12/17/2022]
Abstract
Following spinal cord injury, astrocytes at the site of injury become reactive and exhibit a neurotoxic (A1) phenotype, which leads to neuronal death. In addition, the glial scar, which is composed of reactive astrocytes, acts as a chemical and physical barrier to subsequent axonal regeneration. Biomaterials, specifically electrospun fibers, induce a migratory phenotype of astrocytes and promote regeneration of axons following acute spinal cord injury in preclinical models. However, no study has examined the potential of electrospun fibers or biomaterials in general to modulate neurotoxic (A1) or neuroprotective (A2) astrocytic phenotypes. To assess astrocyte reactivity in response to aligned poly-l-lactic acid microfibers, naïve spinal cord astrocytes or spinal cord astrocytes primed towards the neurotoxic phenotype (A1) were cultured on fibrous scaffolds. Gene expression analysis of the pan-reactive astrocyte makers (GFAP, Lcn2, SerpinA3), A1 specific markers (H2-D1, SerpinG1), and A2 specific makers (Emp1, S100a10) was done using quantitative polymerase chain reaction (qPCR). Electrospun fibers mildly increased the expression of the pan-reactive and A1-specific markers, showing the ability of fibrous materials to induce a more reactive, A1 phenotype. However, when naïve or activated astrocytes were cultured on fibers in the presence of transforming growth factor β3 (TGFβ3), the expression of A1-specific markers was greatly reduced, which in turn improved neuronal survival in culture.
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31
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Zong X, Li Y, Liu C, Qi W, Han D, Tucker L, Dong Y, Hu S, Yan X, Zhang Q. Theta-burst transcranial magnetic stimulation promotes stroke recovery by vascular protection and neovascularization. Theranostics 2020; 10:12090-12110. [PMID: 33204331 PMCID: PMC7667689 DOI: 10.7150/thno.51573] [Citation(s) in RCA: 78] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Accepted: 09/26/2020] [Indexed: 12/18/2022] Open
Abstract
Rationale: The integrity and function of the blood-brain barrier (BBB) is compromised after stroke. The current study was performed to examine potential beneficial effects and underlying mechanisms of repetitive transcranial magnetic stimulation (rTMS) on angiogenesis and vascular protection, function, and repair following stroke, which are largely unknown. Methods: Using a rat photothrombotic (PT) stroke model, continuous theta-burst rTMS was administered once daily to the infarcted hemisphere for 5 min, beginning 3 h after PT stroke. This treatment was applied for 6 days. BBB integrity, blood flow, vascular associated proteins, angiogenesis, integrity of neuronal morphology and structure, and behavioral outcome were measured and analyzed at 6 and/or 22 days after PT stroke. Results: We report that rTMS significantly mitigated BBB permeabilization and preserved important BBB components ZO-1, claudin-5, occludin, and caveolin-1 from PT-induced degradation. Damage to vascular structure, morphology, and perfusion was ameliorated by rTMS, resulting in improved local tissue oxygenation. This was accompanied with robust protection of critical vascular components and upregulation of regulatory factors. A complex cytokine response was induced by PT, particularly at the late phase. Application of rTMS modulated this response, ameliorating levels of cytokines related to peripheral immune cell infiltration. Further investigation revealed that rTMS promoted and sustained post-ischemic angiogenesis long-term and reduced apoptosis of newborn and existing vascular endothelial cells. Application of rTMS also inhibited PT-induced excessive astrocyte-vasculature interactions and stimulated an A1 to A2 shift in vessel-associated astrocytes. Mechanistic studies revealed that rTMS dramatically increased levels of PDGFRβ associated with A2 astrocytes and their adjacent vasculature. As well, A2 astrocytes displayed marked amplification of the angiogenesis-related factors VEGF and TGFβ. PT induced a rise in vessel-associated expression of HIF-1α that was starkly intensified by rTMS treatment. Finally, rTMS preserved neuronal morphology, synaptic structure integrity and behavioral outcome. Conclusions: These results indicate that rTMS can exert powerful protective and restorative effects on the peri-infarct microvasculature after PT stroke by, in part, promoting HIF-1α signaling and shifting vessel-associated astrocytic polarization to the A2 phenotype. This study provides further support for the potent protective effects of rTMS in the context of ischemic stroke, and these findings implicate vascular repair and protection as an important underlying phenomenon.
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32
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Protective Mechanism and Treatment of Neurogenesis in Cerebral Ischemia. Neurochem Res 2020; 45:2258-2277. [PMID: 32794152 DOI: 10.1007/s11064-020-03092-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Revised: 06/18/2020] [Accepted: 07/08/2020] [Indexed: 12/14/2022]
Abstract
Stroke is the fifth leading cause of death worldwide and is a main cause of disability in adults. Neither currently marketed drugs nor commonly used treatments can promote nerve repair and neurogenesis after stroke, and the repair of neurons damaged by ischemia has become a research focus. This article reviews several possible mechanisms of stroke and neurogenesis and introduces novel neurogenic agents (fibroblast growth factors, brain-derived neurotrophic factor, purine nucleosides, resveratrol, S-nitrosoglutathione, osteopontin, etc.) as well as other treatments that have shown neuroprotective or neurogenesis-promoting effects.
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33
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Sami A, Selzer ME, Li S. Advances in the Signaling Pathways Downstream of Glial-Scar Axon Growth Inhibitors. Front Cell Neurosci 2020; 14:174. [PMID: 32714150 PMCID: PMC7346763 DOI: 10.3389/fncel.2020.00174] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2020] [Accepted: 05/22/2020] [Indexed: 12/15/2022] Open
Abstract
Axon growth inhibitors generated by reactive glial scars play an important role in failure of axon regeneration after CNS injury in mature mammals. Among the inhibitory factors, chondroitin sulfate proteoglycans (CSPGs) are potent suppressors of axon regeneration and are important molecular targets for designing effective therapies for traumatic brain injury or spinal cord injury (SCI). CSPGs bind with high affinity to several transmembrane receptors, including two members of the leukocyte common antigen related (LAR) subfamily of receptor protein tyrosine phosphatases (RPTPs). Recent studies demonstrate that multiple intracellular signaling pathways downstream of these two RPTPs mediate the growth-inhibitory actions of CSPGs. A better understanding of these signaling pathways may facilitate development of new and effective therapies for CNS disorders characterized by axonal disconnections. This review will focus on recent advances in the downstream signaling pathways of scar-mediated inhibition and their potential as the molecular targets for CNS repair.
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Affiliation(s)
- Armin Sami
- Shriners Hospitals Pediatric Research Center, Lewis Katz School of Medicine at Temple University, Philadelphia, PA, United States.,Department of Anatomy and Cell Biology, Lewis Katz School of Medicine at Temple University, Philadelphia, PA, United States
| | - Michael E Selzer
- Shriners Hospitals Pediatric Research Center, Lewis Katz School of Medicine at Temple University, Philadelphia, PA, United States.,Department of Neurology, Lewis Katz School of Medicine at Temple University, Philadelphia, PA, United States
| | - Shuxin Li
- Shriners Hospitals Pediatric Research Center, Lewis Katz School of Medicine at Temple University, Philadelphia, PA, United States.,Department of Anatomy and Cell Biology, Lewis Katz School of Medicine at Temple University, Philadelphia, PA, United States
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34
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Hecker A, Anger P, Braaker PN, Schulze W, Schuster S. High-resolution mapping of injury-site dependent functional recovery in a single axon in zebrafish. Commun Biol 2020; 3:307. [PMID: 32533058 PMCID: PMC7293241 DOI: 10.1038/s42003-020-1034-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Accepted: 05/26/2020] [Indexed: 01/09/2023] Open
Abstract
In non-mammalian vertebrates, some neurons can regenerate after spinal cord injury. One of these, the giant Mauthner (M-) neuron shows a uniquely direct link to a robust survival-critical escape behavior but appears to regenerate poorly. Here we use two-photon microscopy in parallel with behavioral assays in zebrafish to show that the M-axon can regenerate very rapidly and that the recovery of functionality lags by just days. However, we also find that the site of the injury is critical: While regeneration is poor both close and far from the soma, rapid regeneration and recovery of function occurs for injuries between 10% and 50% of total axon length. Our findings show that rapid regeneration and the recovery of function can be studied at remarkable temporal resolution after targeted injury of one single M-axon and that the decision between poor and rapid regeneration can be studied in this one axon. Alexander Hecker et al. study the regeneration potential of the axon of the giant Mauthner (M) neuron in zebrafish. Using two-photon microscopy and behavioral assays, they show that the M-axon can recover rapidly days after injury. They also characterize the optimal injury site that enables rapid regeneration and functional recovery.
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Affiliation(s)
- Alexander Hecker
- Department of Animal Physiology, University of Bayreuth, 95440, Bayreuth, Germany.
| | - Pamela Anger
- Department of Animal Physiology, University of Bayreuth, 95440, Bayreuth, Germany
| | - Philipp N Braaker
- Department of Animal Physiology, University of Bayreuth, 95440, Bayreuth, Germany
| | - Wolfram Schulze
- Department of Animal Physiology, University of Bayreuth, 95440, Bayreuth, Germany
| | - Stefan Schuster
- Department of Animal Physiology, University of Bayreuth, 95440, Bayreuth, Germany.
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35
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Li L, Zhang Y, Mu J, Chen J, Zhang C, Cao H, Gao J. Transplantation of Human Mesenchymal Stem-Cell-Derived Exosomes Immobilized in an Adhesive Hydrogel for Effective Treatment of Spinal Cord Injury. NANO LETTERS 2020; 20:4298-4305. [PMID: 32379461 DOI: 10.1021/acs.nanolett.0c00929] [Citation(s) in RCA: 259] [Impact Index Per Article: 51.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Spinal cord injury is among the most fatal diseases. The complicated inhibitory microenvironment requires comprehensive mitigation. Exosomes derived from mesenchymal stem cells (MSCs) are natural biocarriers of cell paracrine secretions that bear the functions of microenvironment regulation. However, the effective retention, release, and integration of exosomes into the injured spinal cord tissue are poorly defined. Herein, an innovative implantation strategy is established using human MSC-derived exosomes immobilized in a peptide-modified adhesive hydrogel (Exo-pGel). Unlike systemic admistration of exosomes, topical transplantation of the Exo-pGel provides an exosome-encapsulated extracellular matrix to the injured nerve tissue, thereby inducing effecient comprehensive mitigation of the SCI microenvironment. The implanted exosomes exhibit efficient retention and sustained release in the host nerve tissues. The Exo-pGel elicits significant nerve recovery and urinary tissue preservation by effectively mitigating inflammation and oxidation. The Exo-pGel therapy presents a promising strategy for effective treatment of central nervous system diseases based on exosome implantation.
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Affiliation(s)
- Liming Li
- College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, China
- Dr. Li Dak Sum & Yip Yio Chin Center for Stem Cell and Regenerative Medicine, Zhejiang University, Hangzhou 310058, China
| | - Yu Zhang
- College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, China
| | - Jiafu Mu
- College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, China
| | - Jiachen Chen
- College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, China
| | - Chenyang Zhang
- College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, China
| | - Hongcui Cao
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou 310003, China
| | - Jianqing Gao
- College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, China
- Dr. Li Dak Sum & Yip Yio Chin Center for Stem Cell and Regenerative Medicine, Zhejiang University, Hangzhou 310058, China
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Involvement of the G-Protein-Coupled Receptor 4 in the Increased Expression of RANK/RANKL/OPG System and Neurotrophins by Nucleus Pulposus Cells under the Degenerated Intervertebral Disc-Like Acidic Microenvironment. BIOMED RESEARCH INTERNATIONAL 2020; 2020:1328436. [PMID: 32566653 PMCID: PMC7277045 DOI: 10.1155/2020/1328436] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Revised: 03/22/2020] [Accepted: 04/01/2020] [Indexed: 12/05/2022]
Abstract
Intervertebral disc (IVD) degeneration is associated with local inflammation and increased expression of neurotrophins. Acidic microenvironment is believed to cause the progression of IVD degeneration. However, there is a paucity of information regarding the relationship between acidic microenvironment and the inflammation and expression of neurotrophins in IVD. G-protein-coupled receptor 4 (GPR4) is a pH-sensing receptor, which can activate the inflammation and increase the expression levels of nerve growth factor in acidic microenvironment. In this study, culture media with pH 7.2 (representing the normal IVD-like acidic condition) and pH 6.5 (degenerated IVD-like acidic condition) were prepared. The gene and protein expression levels of GPR4 in SD rat nucleus pulposus cells were determined under the acidic conditions. And cyclic AMP (cAMP), the second messenger of GPR4, was assayed. Furthermore, the expression levels of receptor activator of nuclear factor κ B (RANK), RANKL ligand (RANKL), osteoprotegerin (OPG), nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), and neurotrophin-3 (NT-3) were also determined. To clarify the involvement of GPR4 in the upregulation of the expression of RANK/RANKL/OPG system and neurotrophins, gene knockdown and forced expression of GPR4 and inhibiting its downstream cAMP accumulation and Ca2+ mobilization were performed. The alternation of the expression levels of matrix metalloproteinase-3 (MMP-3), MMP-13, and aggrecanase-2 (ADAMTS-5) were evaluated by RT-PCR and western blot. The results showed that GPR4 was expressed in rat nucleus pulposus cells, and the expression was upregulated under the degenerated IVD-like acidic microenvironment. cAMP accumulation levels were increased under the degenerated IVD-like acidic culture conditions. The expression levels of RANK, RANKL, OPG, NGF, and BNDF were significantly upregulated under the degenerated IVD-like acidic microenvironment. GPR4 knockdown and reduction of cAMP by the inhibitor SQ22536 abolished the upregulation of the expression of RANK, RANKL, OPG, NGF, and BNDF under the degenerated IVD-like acidic microenvironment. On the opposite, acidosis-induced cAMP accumulation and upregulation of RANK, RANKL, OPG, NGF, and BNDF were further promoted by GPR4 overexpression. The expression levels of MMP-3, MMP-13, and ADAMTS-5 were upregulated under the degenerated IVD-like acidic condition, which can be promoted or attenuated by GPR4 overexpression or knockdown, respectively. We concluded that GPR4-mediated cAMP accumulation was involved in the increased expression of RANK/RANKL/OPG system and neurotrophins by nucleus pulposus cells under the degenerated IVD-like acidic microenvironment.
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Methimazole Inhibits the Expression of GFAP and the Migration of Astrocyte in Scratched Wound Model In Vitro. Mediators Inflamm 2020; 2020:4027470. [PMID: 32351321 PMCID: PMC7174957 DOI: 10.1155/2020/4027470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 03/07/2020] [Accepted: 03/31/2020] [Indexed: 11/21/2022] Open
Abstract
Astrocytes respond to central nervous system (CNS) insults with varieties of changes, such as cellular hypertrophy, migration, proliferation, scar formation, and upregulation of glial fibrillary acidic protein (GFAP) expression. While scar formation plays a very important role in wound healing and prevents further bleeding by forming a physical barrier, it is also one of key features of CNS injury, resulting in glial scar formation (astrogliosis), which is closely related to treatment resistant epilepsy, chronic pain, and other devastating diseases. Therefore, slowing the astrocytic activation process may give a time window of axonal growth after the CNS injury. However, the underlying mechanism of astrocytic activation remains unclear, and there is no effective therapeutic strategy to attenuate the activation process. Here, we found that methimazole could effectively inhibit the GFAP expression in physiological and pathological conditions. Moreover, we scratched primary cultures of cerebral cortical astrocytes with and without methimazole pretreatment and investigated whether methimazole could slow the healing process in these cultures. We found that methimazole could inhibit the GFAP protein expression in scratched astrocytes and prolong the latency of wound healing in cultures. We also measured the phosphorylation of extracellular signal-regulated kinase (ERK) in these cultures and found that methimazole could significantly inhibit the scratch-induced GFAP upregulation. For the first time, our study demonstrated that methimazole might be a possible compound that could inhibit the astrocytic activation following CNS injury by reducing the ERK phosphorylation in astrocytes.
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Tran AP, Warren PM, Silver J. Regulation of autophagy by inhibitory CSPG interactions with receptor PTPσ and its impact on plasticity and regeneration after spinal cord injury. Exp Neurol 2020; 328:113276. [PMID: 32145250 DOI: 10.1016/j.expneurol.2020.113276] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Revised: 03/02/2020] [Accepted: 03/03/2020] [Indexed: 12/15/2022]
Abstract
Chondroitin sulfate proteoglycans (CSPGs), extracellular matrix molecules that increase dramatically following a variety of CNS injuries or diseases, have long been known for their potent capacity to curtail cell migrations as well as axon regeneration and sprouting. The inhibition can be conferred through binding to their major cognate receptor, Protein Tyrosine Phosphatase Sigma (PTPσ). However, the precise mechanisms downstream of receptor binding that mediate growth inhibition have remained elusive. Recently, CSPGs/PTPσ interactions were found to regulate autophagic flux at the axon growth cone by dampening the autophagosome-lysosomal fusion step. Because of the intense interest in autophagic phenomena in the regulation of a wide variety of critical cellular functions, we summarize here what is currently known about dysregulation of autophagy following spinal cord injury, and highlight this critical new mechanism underlying axon regeneration failure. Furthermore, we review how CSPGs/PTPσ interactions influence plasticity through autophagic regulation and how PTPσ serves as a switch to execute either axon outgrowth or synaptogenesis. This has exciting implications for the role CSPGs play not only in axon regeneration failure after spinal cord injury, but also in neurodegenerative diseases where, again, inhibitory CSPGs are upregulated.
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Affiliation(s)
- Amanda Phuong Tran
- Seattle Children's Hospital Research Institute, Integrative Center for Brain Research, Seattle, Washington, USA
| | - Philippa Mary Warren
- King's College London, Regeneration Group, The Wolfson Centre for Age-Related Diseases, Guy's Campus, London Bridge, London, UK
| | - Jerry Silver
- Case Western Reserve University, School of Medicine, Department of Neurosciences, Cleveland, OH, USA.
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Lindsay SL, McCanney GA, Willison AG, Barnett SC. Multi-target approaches to CNS repair: olfactory mucosa-derived cells and heparan sulfates. Nat Rev Neurol 2020; 16:229-240. [PMID: 32099190 DOI: 10.1038/s41582-020-0311-0] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/13/2020] [Indexed: 02/06/2023]
Abstract
Spinal cord injury (SCI) remains one of the biggest challenges in the development of neuroregenerative therapeutics. Cell transplantation is one of numerous experimental strategies that have been identified and tested for efficacy at both preclinical and clinical levels in recent years. In this Review, we briefly discuss the state of human olfactory cell transplantation as a therapy, considering both its current clinical status and its limitations. Furthermore, we introduce a mesenchymal stromal cell derived from human olfactory tissue, which has the potential to induce multifaceted reparative effects in the environment within and surrounding the lesion. We argue that no single therapy will be sufficient to treat SCI effectively and that a combination of cell-based, rehabilitation and pharmaceutical interventions is the most promising approach to aid repair. For this reason, we also introduce a novel pharmaceutical strategy based on modifying the activity of heparan sulfate, an important regulator of a wide range of biological cell functions. The multi-target approach that is exemplified by these types of strategies will probably be necessary to optimize SCI treatment.
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Affiliation(s)
- Susan L Lindsay
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - George A McCanney
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Alice G Willison
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Susan C Barnett
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK.
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40
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Wang Z, Zheng Y, Zheng M, Zhong J, Ma F, Zhou B, Zhu J. Neurogenic Niche Conversion Strategy Induces Migration and Functional Neuronal Differentiation of Neural Precursor Cells Following Brain Injury. Stem Cells Dev 2020; 29:235-248. [PMID: 31797735 DOI: 10.1089/scd.2019.0147] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Glial scars formed after brain injuries provide permissive cues for endogenous neural precursor/stem cells (eNP/SCs) to undergo astrogenesis rather than neurogenesis. Following brain injury, eNP/SCs from the subventricular zone leave their niche, migrate to the injured cortex, and differentiate into reactive astrocytes that contribute to glial scar formation. In vivo neuronal reprogramming, directly converting non-neuronal cells such as reactive astrocytes or NG2 glia into neurons, has greatly improved brain injury repair strategies. However, reprogramming carries a high risk of future clinical applications such as tumorigenicity, involving virus. In this study, we constructed a neural matrix to alter the adverse niche at the injured cortex, enabling eNP/SCs to differentiate into functional neurons. We found that the neural matrix functioned as a "glial trap" that largely concentrated and limited reactive astrocytes to the core of the lesion area, thus altering the adverse niche. The eNP/SCs migrated toward the injured cortex and differentiated into functional neurons. In addition, regenerated neurites extended across the boundary of the injured cortex. Mice treated with the neural matrix demonstrated significant behavioral recovery. For the first time, we induced eNP/SC-derived functional neurons in the cortex after brain injury without the use of viruses, microRNAs, or small molecules. Our novel strategy of applying this "glial trap" to obtain functional neurons in the injured cortex may provide a safer and more natural therapeutic alternative to reprogramming in future clinical applications.
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Affiliation(s)
- Zhifu Wang
- Department of Neurosurgery, Huashan Hospital and National Key Laboratory of Medical Neurobiology, Institutes of Brain Science, Shanghai Medical College, Fudan University, Shanghai, China
| | - Yongtao Zheng
- Department of Neurosurgery, Huashan Hospital and National Key Laboratory of Medical Neurobiology, Institutes of Brain Science, Shanghai Medical College, Fudan University, Shanghai, China
| | - Mingzhe Zheng
- Department of Neurosurgery, Huashan Hospital and National Key Laboratory of Medical Neurobiology, Institutes of Brain Science, Shanghai Medical College, Fudan University, Shanghai, China
| | - Junjie Zhong
- Department of Neurosurgery, Huashan Hospital and National Key Laboratory of Medical Neurobiology, Institutes of Brain Science, Shanghai Medical College, Fudan University, Shanghai, China
| | - Fukai Ma
- Department of Neurosurgery, Huashan Hospital and National Key Laboratory of Medical Neurobiology, Institutes of Brain Science, Shanghai Medical College, Fudan University, Shanghai, China.,Neurosurgery Department, Shanghai Tenth People's Hospital, Tongji University, Shanghai, China
| | - Bin Zhou
- State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences (CAS), University of Chinese Academy of Sciences, Shanghai, China
| | - Jianhong Zhu
- Department of Neurosurgery, Huashan Hospital and National Key Laboratory of Medical Neurobiology, Institutes of Brain Science, Shanghai Medical College, Fudan University, Shanghai, China
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41
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Pearson CS, Solano AG, Tilve SM, Mencio CP, Martin KR, Geller HM. Spatiotemporal distribution of chondroitin sulfate proteoglycans after optic nerve injury in rodents. Exp Eye Res 2019; 190:107859. [PMID: 31705897 DOI: 10.1016/j.exer.2019.107859] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Revised: 09/16/2019] [Accepted: 10/22/2019] [Indexed: 02/08/2023]
Abstract
The accumulation of chondroitin sulfate proteoglycans (CSPGs) in the glial scar following acute damage to the central nervous system (CNS) limits the regeneration of injured axons. Given the rich diversity of CSPG core proteins and patterns of GAG sulfation, identifying the composition of these CSPGs is essential for understanding their roles in injury and repair. Differential expression of core proteins and sulfation patterns have been characterized in the brain and spinal cord of mice and rats, but a comprehensive study of these changes following optic nerve injury has not yet been performed. Here, we show that the composition of CSPGs in the optic nerve and retina following optic nerve crush (ONC) in mice and rats exhibits an increase in aggrecan, brevican, phosphacan, neurocan and versican, similar to changes following spinal cord injury. We also observe an increase in inhibitory 4-sulfated (4S) GAG chains, which suggests that the persistence of CSPGs in the glial scar opposes the growth of CNS axons, thereby contributing to the failure of regeneration and recovery of function.
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Affiliation(s)
- Craig S Pearson
- Laboratory of Developmental Neurobiology, National Heart, Lung, Blood Institute, National Institutes of Health, Bethesda, MD, USA; Department of Clinical Neurosciences, University of Cambridge, United Kingdom
| | - Andrea G Solano
- Laboratory of Developmental Neurobiology, National Heart, Lung, Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Sharada M Tilve
- Laboratory of Developmental Neurobiology, National Heart, Lung, Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Caitlin P Mencio
- Laboratory of Developmental Neurobiology, National Heart, Lung, Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Keith R Martin
- Department of Clinical Neurosciences, University of Cambridge, United Kingdom
| | - Herbert M Geller
- Laboratory of Developmental Neurobiology, National Heart, Lung, Blood Institute, National Institutes of Health, Bethesda, MD, USA.
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42
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Santiago-Toledo G, Georgiou M, Dos Reis J, Roberton VH, Valinhas A, Wood RC, Phillips JB, Mason C, Li D, Li Y, Sinden JD, Choi D, Jat PS, Wall IB. Generation of c-MycER TAM-transduced human late-adherent olfactory mucosa cells for potential regenerative applications. Sci Rep 2019; 9:13190. [PMID: 31519924 PMCID: PMC6744411 DOI: 10.1038/s41598-019-49315-6] [Citation(s) in RCA: 3] [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: 07/25/2018] [Accepted: 07/31/2019] [Indexed: 12/17/2022] Open
Abstract
Human olfactory mucosa cells (hOMCs) have been transplanted to the damaged spinal cord both pre-clinically and clinically. To date mainly autologous cells have been tested. However, inter-patient variability in cell recovery and quality, and the fact that the neuroprotective olfactory ensheathing cell (OEC) subset is difficult to isolate, means an allogeneic hOMC therapy would be an attractive "off-the-shelf" alternative. The aim of this study was to generate a candidate cell line from late-adherent hOMCs, thought to contain the OEC subset. Primary late-adherent hOMCs were transduced with a c-MycERTAM gene that enables cell proliferation in the presence of 4-hydroxytamoxifen (4-OHT). Two c-MycERTAM-derived polyclonal populations, PA5 and PA7, were generated and expanded. PA5 cells had a normal human karyotype (46, XY) and exhibited faster growth kinetics than PA7, and were therefore selected for further characterisation. PA5 hOMCs express glial markers (p75NTR, S100ß, GFAP and oligodendrocyte marker O4), neuronal markers (nestin and ß-III-tubulin) and fibroblast-associated markers (CD90/Thy1 and fibronectin). Co-culture of PA5 cells with a neuronal cell line (NG108-15) and with primary dorsal root ganglion (DRG) neurons resulted in significant neurite outgrowth after 5 days. Therefore, c-MycERTAM-derived PA5 hOMCs have potential as a regenerative therapy for neural cells.
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Affiliation(s)
| | - Melanie Georgiou
- Department of Biochemical Engineering, University College London, London, WC1H 0AH, UK
| | - Joana Dos Reis
- Department of Biochemical Engineering, University College London, London, WC1H 0AH, UK
| | - Victoria H Roberton
- Department of Biochemical Engineering, University College London, London, WC1H 0AH, UK
| | - Ana Valinhas
- Department of Biochemical Engineering, University College London, London, WC1H 0AH, UK
| | - Rachael C Wood
- Department of Biochemical Engineering, University College London, London, WC1H 0AH, UK
- Aston Medical Research Institute and School of Life & Health Sciences, Aston University, Birmingham, B4 7ET, UK
| | - James B Phillips
- Department of Pharmacology, UCL School of Pharmacy, London, WC1N 1AX, UK
- UCL Centre for Nerve Engineering, London, WC1E 6BT, UK
| | - Chris Mason
- Department of Biochemical Engineering, University College London, London, WC1H 0AH, UK
- AVROBIO Inc, Cambridge, MA 02139, USA
| | - Daqing Li
- Department of Neurosurgery, National Hospital for Neurology & Neurosurgery, London, WC1N 3BG, UK
| | - Ying Li
- Department of Neurosurgery, National Hospital for Neurology & Neurosurgery, London, WC1N 3BG, UK
| | - John D Sinden
- UCL Centre for Nerve Engineering, London, WC1E 6BT, UK
- ReNeuron Limited, Pencoed, Bridgend, CF35 5HY, UK
| | - David Choi
- UCL Centre for Nerve Engineering, London, WC1E 6BT, UK
- Department of Neurosurgery, National Hospital for Neurology & Neurosurgery, London, WC1N 3BG, UK
| | - Parmjit S Jat
- MRC Prion Unit at UCL, Institute of Prion Diseases, London, W1W 7FF, UK
| | - Ivan B Wall
- Department of Biochemical Engineering, University College London, London, WC1H 0AH, UK.
- Aston Medical Research Institute and School of Life & Health Sciences, Aston University, Birmingham, B4 7ET, UK.
- Institute of Tissue Regeneration Engineering (ITREN), Dankook University, Cheonan, 31116, Republic of Korea.
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43
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Niknam P, Raoufy MR, Fathollahi Y, Javan M. Modulating proteoglycan receptor PTPσ using intracellular sigma peptide improves remyelination and functional recovery in mice with demyelinated optic chiasm. Mol Cell Neurosci 2019; 99:103391. [DOI: 10.1016/j.mcn.2019.103391] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Revised: 06/20/2019] [Accepted: 07/01/2019] [Indexed: 11/29/2022] Open
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Bradbury EJ, Burnside ER. Moving beyond the glial scar for spinal cord repair. Nat Commun 2019; 10:3879. [PMID: 31462640 PMCID: PMC6713740 DOI: 10.1038/s41467-019-11707-7] [Citation(s) in RCA: 450] [Impact Index Per Article: 75.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Accepted: 07/25/2019] [Indexed: 02/08/2023] Open
Abstract
Traumatic spinal cord injury results in severe and irreversible loss of function. The injury triggers a complex cascade of inflammatory and pathological processes, culminating in formation of a scar. While traditionally referred to as a glial scar, the spinal injury scar in fact comprises multiple cellular and extracellular components. This multidimensional nature should be considered when aiming to understand the role of scarring in limiting tissue repair and recovery. In this Review we discuss recent advances in understanding the composition and phenotypic characteristics of the spinal injury scar, the oversimplification of defining the scar in binary terms as good or bad, and the development of therapeutic approaches to target scar components to enable improved functional outcome after spinal cord injury.
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Affiliation(s)
- Elizabeth J Bradbury
- King's College London, Regeneration Group, The Wolfson Centre for Age-Related Diseases, Institute of Psychiatry, Psychology & Neuroscience (IoPPN), Guy's Campus, London Bridge, London, SE1 1UL, UK.
| | - Emily R Burnside
- King's College London, Regeneration Group, The Wolfson Centre for Age-Related Diseases, Institute of Psychiatry, Psychology & Neuroscience (IoPPN), Guy's Campus, London Bridge, London, SE1 1UL, UK
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45
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Fawcett JW. The Struggle to Make CNS Axons Regenerate: Why Has It Been so Difficult? Neurochem Res 2019; 45:144-158. [PMID: 31388931 PMCID: PMC6942574 DOI: 10.1007/s11064-019-02844-y] [Citation(s) in RCA: 87] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Revised: 07/09/2019] [Accepted: 07/19/2019] [Indexed: 12/12/2022]
Abstract
Axon regeneration in the CNS is inhibited by many extrinsic and intrinsic factors. Because these act in parallel, no single intervention has been sufficient to enable full regeneration of damaged axons in the adult mammalian CNS. In the external environment, NogoA and CSPGs are strongly inhibitory to the regeneration of adult axons. CNS neurons lose intrinsic regenerative ability as they mature: embryonic but not mature neurons can grow axons for long distances when transplanted into the adult CNS, and regeneration fails with maturity in in vitro axotomy models. The causes of this loss of regeneration include partitioning of neurons into axonal and dendritic fields with many growth-related molecules directed specifically to dendrites and excluded from axons, changes in axonal signalling due to changes in expression and localization of receptors and their ligands, changes in local translation of proteins in axons, and changes in cytoskeletal dynamics after injury. Also with neuronal maturation come epigenetic changes in neurons, with many of the transcription factor binding sites that drive axon growth-related genes becoming inaccessible. The overall aim for successful regeneration is to ensure that the right molecules are expressed after axotomy and to arrange for them to be transported to the right place in the neuron, including the damaged axon tip.
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Affiliation(s)
- James W Fawcett
- John Van Geest Centre for Brain Repair, University of Cambridge, Robinson Way, Cambridge, CB2 0PY, UK.
- Centre of Reconstructive Neuroscience, Institute for Experimental Medicine ASCR, Prague, Czech Republic.
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46
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TGF-β Secretion by M2 Macrophages Induces Glial Scar Formation by Activating Astrocytes In Vitro. J Mol Neurosci 2019; 69:324-332. [PMID: 31327154 DOI: 10.1007/s12031-019-01361-5] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Accepted: 06/25/2019] [Indexed: 02/07/2023]
Abstract
Transforming growth factor-β (TGF-β) is a key factor that promotes fibrosis or scar formation, which could become an obstacle in the repair of impaired axons in the central nervous system (CNS) of the human body resulting from diseases or injuries. Considering that major pathological reactions occur during this process, we focused on TGF-secreting M2 macrophages to identify the interactions between M2 macrophages and astrocytes (AS) and verify the specific mechanism of fibrosis or glial scar formation. In the present study, we used the Transwell coculturing technique and found an increase in glial fibrillary acidic protein (GFAP), neurocan, IL-13, and TGF-β expression after incubation for 48 h; the expression of these proteins decreased when additional inhibitors of the TGF-β receptor were added. We concluded that fibrosis or glial scar formation would be enhanced by the secretion of neurocan from AS, resulting from the release of TGF-β from M2 macrophages. We also used M2 macrophage-conditioned medium to further confirm this finding in a subsequent experiment. We hope that the findings in this research could provide a foundation for locating new targets for treating CNS diseases or injuries.
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47
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Ghosh B, Zhang C, Ziemba KS, Fletcher AM, Yurek DM, Smith GM. Partial Reconstruction of the Nigrostriatal Circuit along a Preformed Molecular Guidance Pathway. MOLECULAR THERAPY-METHODS & CLINICAL DEVELOPMENT 2019; 14:217-227. [PMID: 31417940 PMCID: PMC6690717 DOI: 10.1016/j.omtm.2019.06.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Accepted: 06/25/2019] [Indexed: 01/09/2023]
Abstract
The overall goal of our research is to establish a preformed molecular guidance pathway to direct the growth of dopaminergic axons from embryonic ventral mesencephalon (VM), tissue placed within the substantia nigra (SN), into the striatum to reconstruct the nigrostriatal pathway in a hemi-Parkinson's disease rat model. Guidance pathways were prepared by injecting lentivirus encoding either GFP or a combination of glial-cell-line-derived neurotrophic factor (GDNF) with either GDNF family receptor α1 (GFRα1) or netrin1. In another cohort of animals, adeno-associated virus (AAV) encoding brain-derived neurotrophic factor (BDNF) was injected within the striatum after guidance pathway formation. GDNF combined with either GFRα1 or netrin significantly increased growth of dopaminergic axons out of transplants and along the pathway, resulting in a significant reduction in the number of amphetamine-induced rotations. Retrograde tract tracing showed that the dopaminergic axons innervating the striatum were from A9 neurons within the transplant. Increased dopaminergic innervation of the striatum and improved behavioral recovery were observed with the addition of BDNF. Preformed guidance pathways using a combination of GDNF and netrin1 can be used to reconstruct the nigrostriatal pathway and improve motor recovery.
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Affiliation(s)
- Biswarup Ghosh
- Center for Neural Repair and Rehabilitation, Shriners Hospitals Pediatric Research Center, Lewis Katz School of Medicine, Temple University, Philadelphia, PA 19104, USA
| | - Chen Zhang
- Department of Physiology, University of Kentucky College of Medicine, Lexington, KY 40536, USA
| | - Kristine S. Ziemba
- Department of Physiology, University of Kentucky College of Medicine, Lexington, KY 40536, USA
| | - Anita M. Fletcher
- Department of Neurology, University of Louisville School of Medicine, Louisville, KY 40202, USA
| | - David M. Yurek
- Department of Neurosurgery and University of Kentucky Nanobiotechnology Center, University of Kentucky College of Medicine, Lexington, KY 40536, USA
| | - George M. Smith
- Center for Neural Repair and Rehabilitation, Shriners Hospitals Pediatric Research Center, Lewis Katz School of Medicine, Temple University, Philadelphia, PA 19104, USA
- Corresponding author: George M. Smith, Center for Neural Repair and Rehabilitation, Shriners Hospitals Pediatric Research Center, Lewis Katz School of Medicine, Temple University, 3500 N. Broad St., MERB 6th Floor, Philadelphia, PA 19140, USA.
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48
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Stephenson EL, Mishra MK, Moussienko D, Laflamme N, Rivest S, Ling CC, Yong VW. Chondroitin sulfate proteoglycans as novel drivers of leucocyte infiltration in multiple sclerosis. Brain 2019; 141:1094-1110. [PMID: 29506186 DOI: 10.1093/brain/awy033] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Accepted: 01/04/2018] [Indexed: 12/28/2022] Open
Abstract
Multiple sclerosis presents with profound changes in the network of molecules involved in maintaining central nervous system architecture, the extracellular matrix. The extracellular matrix components, particularly the chondroitin sulfate proteoglycans, have functions beyond structural support including their potential interaction with, and regulation of, inflammatory molecules. To investigate the roles of chondroitin sulfate proteoglycans in multiple sclerosis, we used the experimental autoimmune encephalomyelitis model in a time course study. We found that the 4-sulfated glycosaminoglycan side chains of chondroitin sulfate proteoglycans, and the core protein of a particular family member, versican V1, were upregulated in the spinal cord of mice at peak clinical severity, correspondent with areas of inflammation. Versican V1 expression in the spinal cord rose progressively over the course of experimental autoimmune encephalomyelitis. A particular structure in the spinal cord and cerebellum that presented with intense upregulation of chondroitin sulfate proteoglycans is the leucocyte-containing perivascular cuff, an important portal of entry of immune cells into the central nervous system parenchyma. In these inflammatory perivascular cuffs, versican V1 and the glycosaminoglycan side chains of chondroitin sulfate proteoglycans were observed by immunohistochemistry within and in proximity to lymphocytes and macrophages as they migrated across the basement membrane into the central nervous system. Expression of versican V1 transcript was also documented in infiltrating CD45+ leucocytes and F4/80+ macrophages by in situ hybridization. To test the hypothesis that the chondroitin sulfate proteoglycans regulate leucocyte mobility, we used macrophages in tissue culture studies. Chondroitin sulfate proteoglycans significantly upregulated pro-inflammatory cytokines and chemokines in macrophages. Strikingly, and more potently than the toll-like receptor-4 ligand lipopolysaccharide, chondroitin sulfate proteoglycans increased the levels of several members of the matrix metalloproteinase family, which are implicated in the capacity of leucocytes to cross barriers. In support, the migratory capacity of macrophages in vitro in a Boyden chamber transwell assay was enhanced by chondroitin sulfate proteoglycans. Finally, using brain specimens from four subjects with multiple sclerosis with active lesions, we found chondroitin sulfate proteoglycans to be associated with leucocytes in inflammatory perivascular cuffs in all four patients. We conclude that the accumulation of chondroitin sulfate proteoglycans in the perivascular cuff in multiple sclerosis and experimental autoimmune encephalomyelitis boosts the activity and migration of leucocytes across the glia limitans into the central nervous system parenchyma. Thus, chondroitin sulfate proteoglycans represent a new class of molecules to overcome in order to reduce the inflammatory cascades and clinical severity of multiple sclerosis.
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Affiliation(s)
- Erin L Stephenson
- Hotchkiss Brain Institute and the Department of Clinical Neurosciences, University of Calgary, Alberta, Canada
| | - Manoj K Mishra
- Hotchkiss Brain Institute and the Department of Clinical Neurosciences, University of Calgary, Alberta, Canada
| | - Daniel Moussienko
- Hotchkiss Brain Institute and the Department of Clinical Neurosciences, University of Calgary, Alberta, Canada
| | - Nataly Laflamme
- Department of Molecular Medicine, CHU de Quebec Research Center, Laval University, Quebec, Canada
| | - Serge Rivest
- Department of Molecular Medicine, CHU de Quebec Research Center, Laval University, Quebec, Canada
| | - Chang-Chun Ling
- Department of Chemistry, University of Calgary, Alberta, Canada
| | - V Wee Yong
- Hotchkiss Brain Institute and the Department of Clinical Neurosciences, University of Calgary, Alberta, Canada
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Ballout N, Rochelle T, Brot S, Bonnet ML, Francheteau M, Prestoz L, Zibara K, Gaillard A. Characterization of Inflammation in Delayed Cortical Transplantation. Front Mol Neurosci 2019; 12:160. [PMID: 31293384 PMCID: PMC6603085 DOI: 10.3389/fnmol.2019.00160] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Accepted: 06/07/2019] [Indexed: 01/30/2023] Open
Abstract
We previously reported that embryonic motor cortical neurons transplanted 1-week after lesion in the adult mouse motor cortex significantly enhances graft vascularization, survival, and proliferation of grafted cells, the density of projections developed by grafted neurons and improves functional repair and recovery. The purpose of the present study is to understand the extent to which post-traumatic inflammation following cortical lesion could influence the survival of grafted neurons and the development of their projections to target brain regions and conversely how transplanted cells can modulate host inflammation. For this, embryonic motor cortical tissue was grafted either immediately or with a 1-week delay into the lesioned motor cortex of adult mice. Immunohistochemistry (IHC) analysis was performed to determine the density and cell morphology of resident and peripheral infiltrating immune cells. Then, in situ hybridization (ISH) was performed to analyze the distribution and temporal mRNA expression pattern of pro-inflammatory or anti-inflammatory cytokines following cortical lesion. In parallel, we analyzed the protein expression of both M1- and M2-associated markers to study the M1/M2 balance switch. We have shown that 1-week after the lesion, the number of astrocytes, microglia, oligodendrocytes, and CD45+ cells were significantly increased along with characteristics of M2 microglia phenotype. Interestingly, the majority of microglia co-expressed transforming growth factor-β1 (TGF-β1), an anti-inflammatory cytokine, supporting the hypothesis that microglial activation is also neuroprotective. Our results suggest that the modulation of post-traumatic inflammation 1-week after cortical lesion might be implicated in the improvement of graft vascularization, survival, and density of projections developed by grafted neurons.
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Affiliation(s)
- Nissrine Ballout
- Laboratoire de Neurosciences Expérimentales et Cliniques, Université de Poitiers, INSERM U1084, Poitiers, France.,Laboratory of Stem Cells, PRASE, DSST, Department of Biology, Faculty of Sciences-I, Lebanese University, Beirut, Lebanon
| | - Tristan Rochelle
- Laboratoire de Neurosciences Expérimentales et Cliniques, Université de Poitiers, INSERM U1084, Poitiers, France
| | - Sebastien Brot
- Laboratoire de Neurosciences Expérimentales et Cliniques, Université de Poitiers, INSERM U1084, Poitiers, France
| | - Marie-Laure Bonnet
- Laboratoire de Neurosciences Expérimentales et Cliniques, Université de Poitiers, INSERM U1084, Poitiers, France.,CHU Poitiers, Poitiers, France
| | - Maureen Francheteau
- Laboratoire de Neurosciences Expérimentales et Cliniques, Université de Poitiers, INSERM U1084, Poitiers, France
| | - Laetitia Prestoz
- Laboratoire de Neurosciences Expérimentales et Cliniques, Université de Poitiers, INSERM U1084, Poitiers, France
| | - Kazem Zibara
- Laboratory of Stem Cells, PRASE, DSST, Department of Biology, Faculty of Sciences-I, Lebanese University, Beirut, Lebanon
| | - Afsaneh Gaillard
- Laboratoire de Neurosciences Expérimentales et Cliniques, Université de Poitiers, INSERM U1084, Poitiers, France
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Knockdown of Fidgetin Improves Regeneration of Injured Axons by a Microtubule-Based Mechanism. J Neurosci 2019; 39:2011-2024. [PMID: 30647150 DOI: 10.1523/jneurosci.1888-18.2018] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Revised: 11/21/2018] [Accepted: 12/24/2018] [Indexed: 12/16/2022] Open
Abstract
Fidgetin is a microtubule-severing protein that pares back the labile domains of microtubules in the axon. Experimental depletion of fidgetin results in elongation of the labile domains of microtubules and faster axonal growth. To test whether fidgetin knockdown assists axonal regeneration, we plated dissociated adult rat DRGs transduced using AAV5-shRNA-fidgetin on a laminin substrate with spots of aggrecan, a growth-inhibitory chondroitin sulfate proteoglycan. This cell culture assay mimics the glial scar formed after CNS injury. Aggrecan is more concentrated at the edge of the spot, such that axons growing from within the spot toward the edge encounter a concentration gradient that causes growth cones to become dystrophic and axons to retract or curve back on themselves. Fidgetin knockdown resulted in faster-growing axons on both laminin and aggrecan and enhanced crossing of axons from laminin onto aggrecan. Strikingly, axons from within the spot grew more avidly against the inhibitory aggrecan concentration gradient to cross onto laminin, without retracting or curving back. We also tested whether depleting fidgetin improves axonal regeneration in vivo after a dorsal root crush in adult female rats. Whereas control DRG neurons failed to extend axons across the dorsal root entry zone after injury, DRG neurons in which fidgetin was knocked down displayed enhanced regeneration of axons across the dorsal root entry zone into the spinal cord. Collectively, these results establish fidgetin as a novel therapeutic target to augment nerve regeneration and provide a workflow template by which microtubule-related targets can be compared in the future.SIGNIFICANCE STATEMENT Here we establish a workflow template from cell culture to animals in which microtubule-based treatments can be tested and compared with one another for their effectiveness in augmenting regeneration of injured axons relevant to spinal cord injury. The present work uses a viral transduction approach to knock down fidgetin from rat neurons, which coaxes nerve regeneration by elevating microtubule mass in their axons. Unlike previous strategies using microtubule-stabilizing drugs, fidgetin knockdown adds microtubule mass that is labile (rather than stable), thereby better recapitulating the growth status of a developing axon.
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