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Gao X, Li R, Luo L, Zhang D, Liu Q, Zhang J, Mao S. Alpha-asarone ameliorates neurological deterioration of intracerebral hemorrhagic rats by alleviating secondary brain injury via anti-excitotoxicity pathways. PHYTOMEDICINE : INTERNATIONAL JOURNAL OF PHYTOTHERAPY AND PHYTOPHARMACOLOGY 2022; 105:154363. [PMID: 35926378 DOI: 10.1016/j.phymed.2022.154363] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Revised: 07/14/2022] [Accepted: 07/26/2022] [Indexed: 06/15/2023]
Abstract
BACKGROUND Secondary brain injury (SBI) has been confirmed as a leading cause for the poor prognosis of patients suffering from intracerebral hemorrhage (ICH). SBI co-exists in ischemia and hemorrhagic stroke. Neuro-excitotoxicity is considered the initiating factor of ICH-induced SBI. Our previous research has revealed alpha-asarone (ASA)'s efficacy against cerebral ischemia-reperfusion stroke by mitigating neuro-excitotoxicity. It is not yet known if ASA exhibit neuroprotection against ICH. PURPOSE This work aimed to investigate ASA's therapeutic effects and potential mechanisms of action against ICH in a classic rat model induced by collagenase Ⅶ injection. METHODS An in vivo ICH model of Sprague-Dawley rats was established by collagenase Ⅶ injection. We administrated different ASA doses (10, 20, or 40 mg/kg, i.p.) at 2 h post-ICH. Then, rats' short- and long-term neurobehavioral function, bodyweight change, and learning and memory ability were blindly evaluated. Histological, Nissl, and flow cytometry were applied to assess the neuronal damage post-ICH. The wet/dry method and Evans blue extravasation estimated brain edema and blood-brain barrier function. Pathway-related proteins were investigated by immunofluorescence staining, enzyme-linked immunosorbent assay, and Western-blot analysis. RESULTS The results demonstrated that ASA ameliorated neurological deterioration, bodyweight loss, and learning and memory ability of ICH rats. Histological, Nissl, and flow cytometry analyses showed that ASA reduced neuronal damage and apoptosis post-ICH. Besides, ASA probably mitigated brain edema and blood-brain barrier dysfunction via inhibiting astrocyte activation and consequent pro-inflammatory response. The mechanism investigation attributed ASA's efficacy to the following aspects: 1) promoting sodium ion excretion, thus blocking excitatory signal transduction along the axon; 2) preventing glutamate-involved pathways, i.e., decrease of N-methyl-d-aspartic acid receptor subunit 2B, increase of glutamate transporter-1, and alleviation of calcium-related cascades, mitochondrion-associated apoptosis, and neuronal autophagy; 3) enhancing the expression of GABAARs, thus abating neuronal excitotoxicity. CONCLUSION Our study first confirmed the effect of ASA on ameliorating the neurobehavioral deterioration of ICH rats, possibly via alleviation of glutamate-involved neuro-excitotoxicity, i.e., calcium cascades, mitochondrion-involved apoptosis, neuronal autophagy, and astrocyte-related inflammation. These findings not only provided a promising drug candidate for clinical treatment of ICH but also shed light on the future drug discovery against ICH.
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Affiliation(s)
- Xiaofeng Gao
- Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry and Sichuan Province, Sichuan Engineering Laboratory for Plant-Sourced Drug and Sichuan Research Center for Drug Precision Industrial Technology, West China School of Pharmacy, Sichuan University, Chengdu, 610041, China
| | - Rui Li
- Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry and Sichuan Province, Sichuan Engineering Laboratory for Plant-Sourced Drug and Sichuan Research Center for Drug Precision Industrial Technology, West China School of Pharmacy, Sichuan University, Chengdu, 610041, China
| | - Lijun Luo
- Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry and Sichuan Province, Sichuan Engineering Laboratory for Plant-Sourced Drug and Sichuan Research Center for Drug Precision Industrial Technology, West China School of Pharmacy, Sichuan University, Chengdu, 610041, China
| | - Di Zhang
- Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry and Sichuan Province, Sichuan Engineering Laboratory for Plant-Sourced Drug and Sichuan Research Center for Drug Precision Industrial Technology, West China School of Pharmacy, Sichuan University, Chengdu, 610041, China
| | - Qi Liu
- Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry and Sichuan Province, Sichuan Engineering Laboratory for Plant-Sourced Drug and Sichuan Research Center for Drug Precision Industrial Technology, West China School of Pharmacy, Sichuan University, Chengdu, 610041, China
| | - Jian Zhang
- Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry and Sichuan Province, Sichuan Engineering Laboratory for Plant-Sourced Drug and Sichuan Research Center for Drug Precision Industrial Technology, West China School of Pharmacy, Sichuan University, Chengdu, 610041, China
| | - Shengjun Mao
- Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry and Sichuan Province, Sichuan Engineering Laboratory for Plant-Sourced Drug and Sichuan Research Center for Drug Precision Industrial Technology, West China School of Pharmacy, Sichuan University, Chengdu, 610041, China.
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Abulseoud OA, Alasmari F, Hussein AM, Sari Y. Ceftriaxone as a Novel Therapeutic Agent for Hyperglutamatergic States: Bridging the Gap Between Preclinical Results and Clinical Translation. Front Neurosci 2022; 16:841036. [PMID: 35864981 PMCID: PMC9294323 DOI: 10.3389/fnins.2022.841036] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Accepted: 06/07/2022] [Indexed: 12/02/2022] Open
Abstract
Dysregulation of glutamate homeostasis is a well-established core feature of neuropsychiatric disorders. Extracellular glutamate concentration is regulated by glutamate transporter 1 (GLT-1). The discovery of a beta-lactam antibiotic, ceftriaxone (CEF), as a safe compound with unique ability to upregulate GLT-1 sparked the interest in testing its efficacy as a novel therapeutic agent in animal models of neuropsychiatric disorders with hyperglutamatergic states. Indeed, more than 100 preclinical studies have shown the efficacy of CEF in attenuating the behavioral manifestations of various hyperglutamatergic brain disorders such as ischemic stroke, amyotrophic lateral sclerosis (ALS), seizure, Huntington’s disease, and various aspects of drug use disorders. However, despite rich and promising preclinical data, only one large-scale clinical trial testing the efficacy of CEF in patients with ALS is reported. Unfortunately, in that study, there was no significant difference in survival between placebo- and CEF-treated patients. In this review, we discussed the translational potential of preclinical efficacy of CEF based on four different parameters: (1) initiation of CEF treatment in relation to induction of the hyperglutamatergic state, (2) onset of response in preclinical models in relation to onset of GLT-1 upregulation, (3) mechanisms of action of CEF on GLT-1 expression and function, and (4) non-GLT-1-mediated mechanisms for CEF. Our detailed review of the literature brings new insights into underlying molecular mechanisms correlating the preclinical efficacy of CEF. We concluded here that CEF may be clinically effective in selected cases in acute and transient hyperglutamatergic states such as early drug withdrawal conditions.
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Affiliation(s)
- Osama A. Abulseoud
- Department of Psychiatry and Psychology, Alex School of Medicine at Mayo Clinic, Phoenix, AZ, United States
- *Correspondence: Osama A. Abulseoud,
| | - Fawaz Alasmari
- Department of Pharmacology and Experimental Therapeutics, University of Toledo, Toledo, OH, United States
- Department of Pharmacology and Toxicology, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Abdelaziz M. Hussein
- Department of Medical Physiology, Faculty of Medicine, Mansoura University, Mansoura, Egypt
| | - Youssef Sari
- Department of Pharmacology and Experimental Therapeutics, University of Toledo, Toledo, OH, United States
- Youssef Sari,
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Taheri F, Sattari E, Hormozi M, Ahmadvand H, Bigdeli MR, Kordestani-Moghadam P, Anbari K, Milanizadeh S, Moghaddasi M. Dose-Dependent Effects of Astaxanthin on Ischemia/Reperfusion Induced Brain Injury in MCAO Model Rat. Neurochem Res 2022; 47:1736-1750. [DOI: 10.1007/s11064-022-03565-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 02/22/2022] [Accepted: 02/28/2022] [Indexed: 12/20/2022]
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Taspinar N, Hacimuftuoglu A, Butuner S, Togar B, Arslan G, Taghizadehghalehjoughi A, Okkay U, Agar E, Stephens R, Turkez H, Abd El-Aty AM. Differential effects of inhibitors of PTZ-induced kindling on glutamate transporters and enzyme expression. Clin Exp Pharmacol Physiol 2021; 48:1662-1673. [PMID: 34409650 DOI: 10.1111/1440-1681.13575] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 07/31/2021] [Accepted: 08/14/2021] [Indexed: 12/01/2022]
Abstract
Epilepsy is a neurological disorder resulting from abnormal neuronal firing in the brain. Glutamate transporters and the glutamate-glutamine cycle play crucial roles in the development of seizures. In the present study, the correlation of epilepsy with glutamate transporters and enzymes was investigated. Herein, male Wistar rats were randomly allocated into four groups (six animals/group); 35 mg/kg pentylenetetrazole (PTZ) was used to induce a kindling model of epilepsy. Once the kindling model was established, animals were treated for 15 days with either valproic acid (VPA, 350 mg/kg) or ceftriaxone (CEF, 200 mg/kg) in addition to the control group receiving saline. After treatment, electrocorticography (ECoG) was performed to record the electrical activity of the cerebral cortex. The glutamate reuptake time (T80 ) was also determined in situ using an in vivo voltammetry. The expression levels of glutamate transporters and enzymes in the M1 and CA3 areas of the brain were determined using a real-time polymerase chain reaction (RT-PCR). ECoG measurements showed that the mean spike number of the PTZ + VPA and PTZ + CEF groups was significantly lower (p < 0.05) than that of the PTZ group. Compared with the PTZ group, VPA or CEF treatment decreased the glutamate reuptake time (T80 ). The expression levels of EAAC1, GLT-1, GLAST, glutamine synthetase (GS), and glutaminase were increased in the PTZ group. Treatment with VPA or CEF enhanced the expression levels of GLT-1, GLAST, EAAC1, and GS, whereas the glutaminase expression level was reduced. The current results suggest that VPA or CEF decreases seizure activity by increasing glutamate reuptake by upregulating GLT-1 and GLAST expression, implying a possible mechanism for treating epilepsy. Also, we have suggested a novel mechanism for the antiepileptic activity of VPA via decreasing glutaminase expression levels. To our knowledge, this is the first study to measure the glutamate reuptake time in situ during the seizure (i.e., real-time measurement).
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Affiliation(s)
- Numan Taspinar
- Department of Medical Pharmacology, Faculty of Medicine, Uşak University, Uşak, Turkey
| | - Ahmet Hacimuftuoglu
- Department of Medical Pharmacology, Faculty of Medicine, Atatürk University, Erzurum, Turkey
| | - Selcuk Butuner
- Department of Medical Pharmacology, Faculty of Medicine, Atatürk University, Erzurum, Turkey
| | - Basak Togar
- Department of Medical Services and Techniques, Vocational School of Health Services, Bayburt University, Bayburt, Turkey
| | - Gokhan Arslan
- Department of Physiology, Faculty of Medicine, Ondokuz Mayıs University, Samsun, Turkey
| | - Ali Taghizadehghalehjoughi
- Department of Pharmacology and Toxicology, Faculty of Veterinary Medicine, Atatürk University, Erzurum, Turkey
| | - Ufuk Okkay
- Department of Medical Pharmacology, Faculty of Medicine, Atatürk University, Erzurum, Turkey
| | - Erdal Agar
- Department of Physiology, Faculty of Medicine, Ondokuz Mayıs University, Samsun, Turkey
| | - Robert Stephens
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, OH, USA
| | - Hasan Turkez
- Department of Medical Biology, Faculty of Medicine, Atatürk University, Erzurum, Turkey
| | - A M Abd El-Aty
- Department of Medical Pharmacology, Faculty of Medicine, Atatürk University, Erzurum, Turkey
- Department of Pharmacology, Faculty of Veterinary Medicine, Cairo University, Giza, Egypt
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Nozohouri S, Zhang Y, Albekairi TH, Vaidya B, Abbruscato TJ. Glutamate Buffering Capacity and Blood-Brain Barrier Protection of Opioid Receptor Agonists Biphalin and Nociceptin. J Pharmacol Exp Ther 2021; 379:260-269. [PMID: 34663677 DOI: 10.1124/jpet.121.000831] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Accepted: 09/29/2021] [Indexed: 12/23/2022] Open
Abstract
Opioids play crucial roles in the regulation of many important brain functions including pain, memory, and neurogenesis. Activation of opioid receptors is reported to have neuroprotective effects after ischemic reperfusion injury. The objective of this study was to understand the role of biphalin and nociceptin, opioid receptor agonists, on blood-brain barrier (BBB) integrity during ischemic stroke. In this study, we aimed to measure the effect of biphalin and nociceptin on astrocytic glutamate uptake and on expression of excitatory amino acid transporter to study the indirect role of astrocytes on opioid receptor-mediated BBB protection during in vitro stroke conditions. We used mouse brain endothelial cells (bEnd.3) and primary astrocytes as an in vitro BBB model. Restrictive BBB properties were evaluated by measuring [14C] sucrose paracellular permeability and the redistribution of the tight junction proteins. The protective effect of biphalin and nociceptin on BBB integrity was assessed after exposing cells to oxygen glucose deprivation (OGD) and glutamate. It was observed that combined stress (2 mM glutamate and 2 hours of OGD) significantly reduced glutamate uptake by astrocytes; however, biphalin and nociceptin treatment increased glutamate uptake in primary astrocytes. This suggests a role of increased astrocytic buffering capacity in opioid-meditated protection of the BBB during ischemic stroke. It was also found that the combined stress significantly increased [14C] sucrose paracellular permeability in an in vitro BBB model. Biphalin and nociceptin treatment attenuated the effect of the combined stress, which was reversed by the opioid receptor antagonists, suggesting the role of opioid receptors in biphalin and nociception's BBB modulatory activity. SIGNIFICANT STATEMENT: There is an unmet need for discovering new efficacious therapeutic agents to offset the deleterious effects of ischemic stroke. Given the confirmed roles of opioid receptors in the regulation of central nervous system functions, opioid receptor agonists have been studied as potential neuroprotective options in ischemic conditions. This study adds to the knowledge about the cerebrovascular protective effects of opioid receptor agonists and provides insight about the mechanism of action of these agents.
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Affiliation(s)
- Saeideh Nozohouri
- Department of Pharmaceutical Sciences, School of Pharmacy, Texas Tech University Health Sciences Center, Amarillo, Texas (S.N., Y.Z., T.H.A., B.V., T.J.A.); and Department of Pharmacology and Toxicology, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia (T.H.A.)
| | - Yong Zhang
- Department of Pharmaceutical Sciences, School of Pharmacy, Texas Tech University Health Sciences Center, Amarillo, Texas (S.N., Y.Z., T.H.A., B.V., T.J.A.); and Department of Pharmacology and Toxicology, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia (T.H.A.)
| | - Thamer H Albekairi
- Department of Pharmaceutical Sciences, School of Pharmacy, Texas Tech University Health Sciences Center, Amarillo, Texas (S.N., Y.Z., T.H.A., B.V., T.J.A.); and Department of Pharmacology and Toxicology, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia (T.H.A.)
| | - Bhuvaneshwar Vaidya
- Department of Pharmaceutical Sciences, School of Pharmacy, Texas Tech University Health Sciences Center, Amarillo, Texas (S.N., Y.Z., T.H.A., B.V., T.J.A.); and Department of Pharmacology and Toxicology, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia (T.H.A.)
| | - Thomas J Abbruscato
- Department of Pharmaceutical Sciences, School of Pharmacy, Texas Tech University Health Sciences Center, Amarillo, Texas (S.N., Y.Z., T.H.A., B.V., T.J.A.); and Department of Pharmacology and Toxicology, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia (T.H.A.)
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Sulbactam improves binding property and uptake capacity of glutamate transporter-1 and decreases glutamate concentration in the CA1 region of hippocampus of global brain ischemic rats. Amino Acids 2021; 53:1649-1661. [PMID: 34716803 DOI: 10.1007/s00726-021-03088-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Accepted: 10/07/2021] [Indexed: 10/19/2022]
Abstract
Glutamate transporter-1 (GLT-1) removes most glutamate in the synaptic cleft. Sulbactam confers neuronal protection against ischemic insults in the hippocampal CA1 region accompanied by the upregulation of GLT-1 expression in rats. The present study further investigates the effect of sulbactam on the binding property and uptake capacity of GLT-1 for glutamate, and the change in extracellular glutamate concentration in the hippocampal CA1 region of rats with global brain ischemia. The binding property and uptake capacity of GLT-1 were measured using a radioligand binding and uptake assay, respectively, with L-3H-glutamate. The extracellular glutamate concentration was detected using microdialysis and high-performance liquid chromatography-mass spectrometry. Neuropathological evaluation was performed based on thionin staining. It was shown that sulbactam pre-treatment changed GLT-1 binding property, including increased Bmax and decreased Kd values, increased GLT-1 uptake capacity for glutamate, and inhibited the elevation of extracellular glutamate concentration in rats with global cerebral ischemia. These effects of sulbactam were accompanied by its neuronal protection on the hippocampal CA1 neurons against delayed neuronal death resulted from ischemic insult. Furthermore, administration of GLT-1 antisense oligodeoxynucleotides, which inhibited the expression of GLT-1, blocked the aforementioned sulbactam-related effects, which suggested that GLT-1 upregulation mediated the above effect although other mechanisms independent of the upregulation of GLT-1 expression could not be excluded. It could be concluded that sulbactam improves the binding property and uptake capacity of GLT-1 for glutamate and then reduces the glutamate concentration and excitotoxicity during global cerebral ischemia, which contributes to the neuroprotection of sulbactam against brain ischemia.
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Nasirishargh A, Kumar P, Ramasubramanian L, Clark K, Hao D, Lazar SV, Wang A. Exosomal microRNAs from mesenchymal stem/stromal cells: Biology and applications in neuroprotection. World J Stem Cells 2021; 13:776-794. [PMID: 34367477 PMCID: PMC8316862 DOI: 10.4252/wjsc.v13.i7.776] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 04/29/2021] [Accepted: 06/22/2021] [Indexed: 02/06/2023] Open
Abstract
Mesenchymal stem/stromal cells (MSCs) are extensively studied as cell-therapy agents for neurological diseases. Recent studies consider exosomes secreted by MSCs as important mediators for MSCs' neuroprotective functions. Exosomes transfer functional molecules including proteins, lipids, metabolites, DNAs, and coding and non-coding RNAs from MSCs to their target cells. Emerging evidence shows that exosomal microRNAs (miRNAs) play a key role in the neuroprotective properties of these exosomes by targeting several genes and regulating various biological processes. Multiple exosomal miRNAs have been identified to have neuroprotective effects by promoting neurogenesis, neurite remodeling and survival, and neuroplasticity. Thus, exosomal miRNAs have significant therapeutic potential for neurological disorders such as stroke, traumatic brain injury, and neuroinflammatory or neurodegenerative diseases and disorders. This review discusses the neuroprotective effects of selected miRNAs (miR-21, miR-17-92, miR-133, miR-138, miR-124, miR-30, miR146a, and miR-29b) and explores their mechanisms of action and applications for the treatment of various neurological disease and disorders. It also provides an overview of state-of-the-art bioengineering approaches for isolating exosomes, optimizing their yield and manipulating the miRNA content of their cargo to improve their therapeutic potential.
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Affiliation(s)
- Aida Nasirishargh
- Surgical Bioengineering Laboratory, Department of Surgery, University of California, Davis School of Medicine, Sacramento, CA 95817, United States
| | - Priyadarsini Kumar
- Surgical Bioengineering Laboratory, Department of Surgery, University of California, Davis School of Medicine, Sacramento, CA 95817, United States
- Institute for Pediatric Regenerative Medicine, Shriners Hospitals for Children, Sacramento, CA 95817, United States
| | - Lalithasri Ramasubramanian
- Surgical Bioengineering Laboratory, Department of Surgery, University of California, Davis School of Medicine, Sacramento, CA 95817, United States
- Department of Biomedical Engineering, University of California Davis, Davis, CA 95616, United States
| | - Kaitlin Clark
- Surgical Bioengineering Laboratory, Department of Surgery, University of California, Davis School of Medicine, Sacramento, CA 95817, United States
- Institute for Pediatric Regenerative Medicine, Shriners Hospitals for Children, Sacramento, CA 95817, United States
| | - Dake Hao
- Surgical Bioengineering Laboratory, Department of Surgery, University of California, Davis School of Medicine, Sacramento, CA 95817, United States
- Institute for Pediatric Regenerative Medicine, Shriners Hospitals for Children, Sacramento, CA 95817, United States
| | - Sabrina V Lazar
- Surgical Bioengineering Laboratory, Department of Surgery, University of California, Davis School of Medicine, Sacramento, CA 95817, United States
| | - Aijun Wang
- Surgical Bioengineering Laboratory, Department of Surgery, University of California, Davis School of Medicine, Sacramento, CA 95817, United States
- Institute for Pediatric Regenerative Medicine, Shriners Hospitals for Children, Sacramento, CA 95817, United States
- Department of Biomedical Engineering, University of California Davis, Davis, CA 95616, United States.
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Kimura A, Suehiro K, Mukai A, Fujimoto Y, Funao T, Yamada T, Mori T. Protective effects of hydrogen gas against spinal cord ischemia-reperfusion injury. J Thorac Cardiovasc Surg 2021; 164:e269-e283. [PMID: 34090694 DOI: 10.1016/j.jtcvs.2021.04.077] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 04/02/2021] [Accepted: 04/17/2021] [Indexed: 10/21/2022]
Abstract
OBJECTIVE This experimental study aimed to assess the efficacy of hydrogen gas inhalation against spinal cord ischemia-reperfusion injury and reveal its mechanism by measuring glutamate concentration in the ventral horn using an in vivo microdialysis method. METHODS Male Sprague-Dawley rats were divided into the following 6 groups: sham, only spinal ischemia, 3% hydrogen gas (spinal ischemia + 3% hydrogen gas), 2% hydrogen gas (spinal ischemia + 2% hydrogen gas), 1% hydrogen gas (spinal ischemia + 1% hydrogen gas), and hydrogen gas dihydrokainate (spinal ischemia + dihydrokainate [selective inhibitor of glutamate transporter-1] + 3% hydrogen gas). Hydrogen gas inhalation was initiated 10 minutes before the ischemia. For the hydrogen gas dihydrokainate group, glutamate transporter-1 inhibitor was administered 20 minutes before the ischemia. Immunofluorescence was performed to assess the expression of glutamate transporter-1 in the ventral horn. RESULTS The increase in extracellular glutamate induced by spinal ischemia was significantly suppressed by 3% hydrogen gas inhalation (P < .05). This effect was produced in increasing order: 1%, 2%, and 3%. Conversely, the preadministration of glutamate transporter-1 inhibitor diminished the suppression of spinal ischemia-induced glutamate increase observed during the inhalation of 3% hydrogen gas. Immunofluorescence indicated the expression of glutamate transporter-1 in the spinal ischemia group was significantly decreased compared with the sham group, which was attenuated by 3% hydrogen gas inhalation (P < .05). CONCLUSIONS Our study demonstrated hydrogen gas inhalation exhibits a protective and concentration-dependent effect against spinal ischemic injury, and glutamate transporter-1 has an important role in the protective effects against spinal cord injury.
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Affiliation(s)
- Aya Kimura
- Department of Anesthesiology, Osaka City University Graduate School of Medicine, Osaka, Japan
| | - Koichi Suehiro
- Department of Anesthesiology, Osaka City University Graduate School of Medicine, Osaka, Japan.
| | - Akira Mukai
- Department of Anesthesiology, Osaka City University Graduate School of Medicine, Osaka, Japan
| | - Yohei Fujimoto
- Department of Anesthesiology, Osaka City University Graduate School of Medicine, Osaka, Japan
| | - Tomoharu Funao
- Department of Anesthesiology, Osaka City University Graduate School of Medicine, Osaka, Japan
| | - Tokuhiro Yamada
- Department of Anesthesiology, Osaka City University Graduate School of Medicine, Osaka, Japan
| | - Takashi Mori
- Department of Anesthesiology, Osaka City University Graduate School of Medicine, Osaka, Japan
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Patabendige A, Singh A, Jenkins S, Sen J, Chen R. Astrocyte Activation in Neurovascular Damage and Repair Following Ischaemic Stroke. Int J Mol Sci 2021; 22:4280. [PMID: 33924191 PMCID: PMC8074612 DOI: 10.3390/ijms22084280] [Citation(s) in RCA: 126] [Impact Index Per Article: 31.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2021] [Revised: 04/11/2021] [Accepted: 04/15/2021] [Indexed: 12/11/2022] Open
Abstract
Transient or permanent loss of tissue perfusion due to ischaemic stroke can lead to damage to the neurovasculature, and disrupt brain homeostasis, causing long-term motor and cognitive deficits. Despite promising pre-clinical studies, clinically approved neuroprotective therapies are lacking. Most studies have focused on neurons while ignoring the important roles of other cells of the neurovascular unit, such as astrocytes and pericytes. Astrocytes are important for the development and maintenance of the blood-brain barrier, brain homeostasis, structural support, control of cerebral blood flow and secretion of neuroprotective factors. Emerging data suggest that astrocyte activation exerts both beneficial and detrimental effects following ischaemic stroke. Activated astrocytes provide neuroprotection and contribute to neurorestoration, but also secrete inflammatory modulators, leading to aggravation of the ischaemic lesion. Astrocytes are more resistant than other cell types to stroke pathology, and exert a regulative effect in response to ischaemia. These roles of astrocytes following ischaemic stroke remain incompletely understood, though they represent an appealing target for neurovascular protection following stroke. In this review, we summarise the astrocytic contributions to neurovascular damage and repair following ischaemic stroke, and explore mechanisms of neuroprotection that promote revascularisation and neurorestoration, which may be targeted for developing novel therapies for ischaemic stroke.
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Affiliation(s)
- Adjanie Patabendige
- Brain Barriers Group, School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, NSW 2321, Australia;
- Priority Research Centre for Stroke and Brain Injury, and Priority Research Centre for Brain & Mental Health, University of Newcastle, Callaghan, NSW 2321, Australia
- Hunter Medical Research Institute, New Lambton Heights, NSW 2305, Australia
- Institute of Infection & Global Health, University of Liverpool, Liverpool L7 3EA, UK
| | - Ayesha Singh
- School of Pharmacy and Bioengineering, Keele University, Staffordshire ST5 5BG, UK;
| | - Stuart Jenkins
- School of Medicine, Keele University, Staffordshire ST5 5BG, UK; (S.J.); (J.S.)
- Neural Tissue Engineering: Keele (NTEK), Keele University, Staffordshire ST5 5BG, UK
| | - Jon Sen
- School of Medicine, Keele University, Staffordshire ST5 5BG, UK; (S.J.); (J.S.)
- Clinical Informatics and Neurosurgery Fellow, The Cleveland Clinic, 33 Grosvenor Square, London SW1X 7HY, UK
| | - Ruoli Chen
- School of Pharmacy and Bioengineering, Keele University, Staffordshire ST5 5BG, UK;
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Wilkie CM, Barron JC, Brymer KJ, Barnes JR, Nafar F, Parsons MP. The Effect of GLT-1 Upregulation on Extracellular Glutamate Dynamics. Front Cell Neurosci 2021; 15:661412. [PMID: 33841104 PMCID: PMC8032948 DOI: 10.3389/fncel.2021.661412] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Accepted: 03/05/2021] [Indexed: 12/21/2022] Open
Abstract
Pharmacological upregulation of glutamate transporter-1 (GLT-1), commonly achieved using the beta-lactam antibiotic ceftriaxone, represents a promising therapeutic strategy to accelerate glutamate uptake and prevent excitotoxic damage in neurological conditions. While excitotoxicity is indeed implicated in numerous brain diseases, it is typically restricted to select vulnerable brain regions, particularly in early disease stages. In healthy brain tissue, the speed of glutamate uptake is not constant and rather varies in both an activity- and region-dependent manner. Despite the widespread use of ceftriaxone in disease models, very little is known about how such treatments impact functional measures of glutamate uptake in healthy tissue, and whether GLT-1 upregulation can mask the naturally occurring activity-dependent and regional heterogeneities in uptake. Here, we used two different compounds, ceftriaxone and LDN/OSU-0212320 (LDN), to upregulate GLT-1 in healthy wild-type mice. We then used real-time imaging of the glutamate biosensor iGluSnFR to investigate functional consequences of GLT-1 upregulation on activity- and regional-dependent variations in glutamate uptake capacity. We found that while both ceftriaxone and LDN increased GLT-1 expression in multiple brain regions, they did not prevent activity-dependent slowing of glutamate clearance nor did they speed basal clearance rates, even in areas characterized by slow uptake (e.g., striatum). Unexpectedly, ceftriaxone but not LDN decreased glutamate release in the cortex, suggesting that ceftriaxone may alter release properties independent of its effects on GLT-1 expression. In sum, our data demonstrate the complexities of glutamate uptake by showing that GLT-1 expression does not necessarily translate to accelerated uptake. Furthermore, these data suggest that the mechanisms underlying activity- and regional-dependent differences in glutamate dynamics are independent of GLT-1 expression levels.
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Affiliation(s)
- Crystal M Wilkie
- Division of Biomedical Sciences, Faculty of Medicine, Memorial University, St. John's, NL, Canada
| | - Jessica C Barron
- Division of Biomedical Sciences, Faculty of Medicine, Memorial University, St. John's, NL, Canada
| | - Kyle J Brymer
- Division of Biomedical Sciences, Faculty of Medicine, Memorial University, St. John's, NL, Canada
| | - Jocelyn R Barnes
- Division of Biomedical Sciences, Faculty of Medicine, Memorial University, St. John's, NL, Canada
| | - Firoozeh Nafar
- Division of Biomedical Sciences, Faculty of Medicine, Memorial University, St. John's, NL, Canada
| | - Matthew P Parsons
- Division of Biomedical Sciences, Faculty of Medicine, Memorial University, St. John's, NL, Canada
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11
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Mora S, Martín-González E, Prados-Pardo Á, Moreno J, López MJ, Pilar-Cuellar F, Castro E, Díaz Á, Flores P, Moreno M. Increased vulnerability to impulsive behavior after streptococcal antigen exposure and antibiotic treatment in rats. Brain Behav Immun 2020; 89:675-688. [PMID: 32798664 DOI: 10.1016/j.bbi.2020.08.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Revised: 08/04/2020] [Accepted: 08/11/2020] [Indexed: 12/13/2022] Open
Abstract
RATIONALE The inflammation induced by Group A Streptococcus (GAS) infection has been viewed as a vulnerability factor in mental disorders characterized by inhibitory control deficits, such as attention-deficit/hyperactivity disorder or obsessive-compulsive disorder. Antibiotic treatment reduces GAS symptoms; however, its effects on impulsivity have not been fully assessed. OBJECTIVES We investigated whether GAS exposure during early adolescence might be a vulnerability factor for adult impulsivity, if antibiotic treatment acts as a protective factor, and whether these differences are accompanied by changes in the inflammatory cytokine frontostriatal regions. METHODS Male Wistar rats were exposed to the GAS antigen or to vehicle plus adjuvants at postnatal day (PND) 35 (with two boosts), and they received either ampicillin (supplemented in the drinking water) or water alone from PND35 to PND70. Adult impulsivity was assessed using two different models, the 5-choice serial reaction time task (5-CSRT task) and the delay discounting task (DDT). The levels of interleukin-6 (IL-6) and IL-17 were measured in the prefrontal cortex (PFc), and the tumor necrosis factor α levels (TNFα) were measured in the PFc and nucleus accumbens (NAcc). RESULTS GAS exposure and ampicillin treatment increased the waiting impulsivity by a higher number of premature responses when the animals were challenged by a long intertrial interval during the 5-CSRT task. The GAS exposure revealed higher impulsive choices at the highest delay (40 s) when tested by DDT, while coadministration with ampicillin prevented the impulsive choice. GAS exposure and ampicillin reduced the IL-6 and IL-17 levels in the PFc, and ampicillin treatment increased the TNFα levels in the NAcc. A regression analysis revealed a significant contribution of GAS exposure and TNFα levels to the observed effects. CONCLUSIONS GAS exposure and ampicillin treatment induced an inhibitory control deficit in a different manner depending on the form of impulsivity measured here, with inflammatory long-term changes in the PFc and NAcc that might increase the vulnerability to impulsivity-related neuropsychiatric disorders.
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Affiliation(s)
- Santiago Mora
- Department of Psychology and Health Research Centre, University of Almería, Carretera de Sacramento s/n, 04120 Almería, Spain
| | - Elena Martín-González
- Department of Psychology and Health Research Centre, University of Almería, Carretera de Sacramento s/n, 04120 Almería, Spain
| | - Ángeles Prados-Pardo
- Department of Psychology and Health Research Centre, University of Almería, Carretera de Sacramento s/n, 04120 Almería, Spain
| | - Joaquín Moreno
- Department of Biology and Geology, CeiA3 and CIAMBITAL, University of Almería, Carretera de Sacramento s/n, 04120 Almería, Spain
| | - María José López
- Department of Biology and Geology, CeiA3 and CIAMBITAL, University of Almería, Carretera de Sacramento s/n, 04120 Almería, Spain
| | - Fuencisla Pilar-Cuellar
- Biomedical Research Networking Center for Mental Health Network (CIBERSAM), Instituto de Salud Carlos III, Santander, Spain; Institute of Biomedicine and Biotechnology of Cantabria (IBBTEC), University of Cantabria-CSIC-SODERCAN, 39011 Santander, Spain; Department of Physiology and Pharmacology, University of Cantabria, 39011 Santander, Spain
| | - Elena Castro
- Biomedical Research Networking Center for Mental Health Network (CIBERSAM), Instituto de Salud Carlos III, Santander, Spain; Institute of Biomedicine and Biotechnology of Cantabria (IBBTEC), University of Cantabria-CSIC-SODERCAN, 39011 Santander, Spain; Department of Physiology and Pharmacology, University of Cantabria, 39011 Santander, Spain
| | - Álvaro Díaz
- Biomedical Research Networking Center for Mental Health Network (CIBERSAM), Instituto de Salud Carlos III, Santander, Spain; Institute of Biomedicine and Biotechnology of Cantabria (IBBTEC), University of Cantabria-CSIC-SODERCAN, 39011 Santander, Spain; Department of Physiology and Pharmacology, University of Cantabria, 39011 Santander, Spain
| | - Pilar Flores
- Department of Psychology and Health Research Centre, University of Almería, Carretera de Sacramento s/n, 04120 Almería, Spain
| | - Margarita Moreno
- Department of Psychology and Health Research Centre, University of Almería, Carretera de Sacramento s/n, 04120 Almería, Spain.
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12
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Castañeda-Cabral JL, López-Ortega JG, Fajardo-Fregoso BF, Beas-Zárate C, Ureña-Guerrero ME. Glutamate induced neonatal excitotoxicity modifies the expression level of EAAT1 (GLAST) and EAAT2 (GLT-1) proteins in various brain regions of the adult rat. Neurosci Lett 2020; 735:135237. [PMID: 32645399 DOI: 10.1016/j.neulet.2020.135237] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2019] [Revised: 07/03/2020] [Accepted: 07/04/2020] [Indexed: 02/08/2023]
Abstract
Glutamate-mediated excitatory synaptic signalling is primarily controlled by excitatory amino acid transporters (EAATs), such as EAAT1 and EAAT2, which are located mostly on astrocytes and, together, uptake more than 95 % of extracellular glutamate. Alterations in the functional expression levels of EAATs can lead to excessive extracellular glutamate accumulation, potentially triggering excitotoxicity and seizures, among other neurological disorders. Excitotoxicity induced in early developmental stages can lead to lasting changes in several neurotransmission systems, including the glutamatergic system, which could make the brain more susceptible to a second insult. In this study, the expression levels of EAAT1 (GLAST) and EAAT2 (GLT-1) proteins were assessed in the cerebral motor cortex (CMC), striatum, hippocampus and entorhinal cortex (EC) of male adult rats following the neonatal excitotoxic process triggered by monosodium glutamate (MSG)-treatment (4 g/kg of body weight at postnatal days 1,3,5 and 7, subcutaneously). Western blot analysis showed that neonatal MSG-treatment decreased EAAT1 expression levels in the CMC, striatum and hippocampus, while EAAT2 levels were increased in the striatum and EC and decreased in the CMC. Immunofluorescence staining confirmed the changes in EAAT1 and EAAT2 expression induced by neonatal MSG-treatment, which were accompanied by an increase in the glial fibrillary acidic protein (GFAP) immunofluorescence signalthat was particularly significant in the hippocampus. Our results show that a neonatal excitotoxic processes can induce lasting changes in the expression levels of EAAT1 and EAAT2 proteins and suggest that although astrogliosis occurs, glutamate uptake could be deficient, particularly in the CMC and hippocampus.
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Affiliation(s)
- José Luis Castañeda-Cabral
- Departamento de Biología Celular y Molecular, Centro Universitario de Ciencias Biológicas y Agropecuarias (CUCBA), Universidad de Guadalajara, Zapopan, Jalisco, Mexico
| | - José Guadalupe López-Ortega
- Departamento de Biología Celular y Molecular, Centro Universitario de Ciencias Biológicas y Agropecuarias (CUCBA), Universidad de Guadalajara, Zapopan, Jalisco, Mexico
| | - Blanca Fabiola Fajardo-Fregoso
- Departamento de Biología Celular y Molecular, Centro Universitario de Ciencias Biológicas y Agropecuarias (CUCBA), Universidad de Guadalajara, Zapopan, Jalisco, Mexico
| | - Carlos Beas-Zárate
- Departamento de Biología Celular y Molecular, Centro Universitario de Ciencias Biológicas y Agropecuarias (CUCBA), Universidad de Guadalajara, Zapopan, Jalisco, Mexico
| | - Mónica E Ureña-Guerrero
- Departamento de Biología Celular y Molecular, Centro Universitario de Ciencias Biológicas y Agropecuarias (CUCBA), Universidad de Guadalajara, Zapopan, Jalisco, Mexico.
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13
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Pajarillo E, Johnson J, Rizor A, Nyarko-Danquah I, Adinew G, Bornhorst J, Stiboller M, Schwerdtle T, Son DS, Aschner M, Lee E. Astrocyte-specific deletion of the transcription factor Yin Yang 1 in murine substantia nigra mitigates manganese-induced dopaminergic neurotoxicity. J Biol Chem 2020; 295:15662-15676. [PMID: 32893191 PMCID: PMC7667968 DOI: 10.1074/jbc.ra120.015552] [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: 08/07/2020] [Revised: 09/02/2020] [Indexed: 12/11/2022] Open
Abstract
Manganese (Mn)-induced neurotoxicity resembles Parkinson's disease (PD), but the mechanisms underpinning its effects remain unknown. Mn dysregulates astrocytic glutamate transporters, GLT-1 and GLAST, and dopaminergic function, including tyrosine hydroxylase (TH). Our previous in vitro studies have shown that Mn repressed GLAST and GLT-1 via activation of transcription factor Yin Yang 1 (YY1). Here, we investigated if in vivo astrocytic YY1 deletion mitigates Mn-induced dopaminergic neurotoxicity, attenuating Mn-induced reduction in GLAST/GLT-1 expression in murine substantia nigra (SN). AAV5-GFAP-Cre-GFP particles were infused into the SN of 8-week-old YY1 flox/flox mice to generate a region-specific astrocytic YY1 conditional knockout (cKO) mouse model. 3 weeks after adeno-associated viral (AAV) infusion, mice were exposed to 330 μg of Mn (MnCl2 30 mg/kg, intranasal instillation, daily) for 3 weeks. After Mn exposure, motor functions were determined in open-field and rotarod tests, followed by Western blotting, quantitative PCR, and immunohistochemistry to assess YY1, TH, GLAST, and GLT-1 levels. Infusion of AAV5-GFAP-Cre-GFP vectors into the SN resulted in region-specific astrocytic YY1 deletion and attenuation of Mn-induced impairment of motor functions, reduction of TH-expressing cells in SN, and TH mRNA/protein levels in midbrain/striatum. Astrocytic YY1 deletion also attenuated the Mn-induced decrease in GLAST/GLT-1 mRNA/protein levels in midbrain. Moreover, YY1 deletion abrogated its interaction with histone deacetylases in astrocytes. These results indicate that astrocytic YY1 plays a critical role in Mn-induced neurotoxicity in vivo, at least in part, by reducing astrocytic GLAST/GLT-1. Thus, YY1 might be a potential target for treatment of Mn toxicity and other neurological disorders associated with dysregulation of GLAST/GLT-1.
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Affiliation(s)
- Edward Pajarillo
- Department of Pharmaceutical Sciences, Florida A&M University, Tallahassee, Florida, USA
| | - James Johnson
- Department of Pharmaceutical Sciences, Florida A&M University, Tallahassee, Florida, USA
| | - Asha Rizor
- Department of Pharmaceutical Sciences, Florida A&M University, Tallahassee, Florida, USA
| | - Ivan Nyarko-Danquah
- Department of Pharmaceutical Sciences, Florida A&M University, Tallahassee, Florida, USA
| | - Getinet Adinew
- Department of Pharmaceutical Sciences, Florida A&M University, Tallahassee, Florida, USA
| | - Julia Bornhorst
- Food Chemistry, Faculty of Mathematics and Natural Sciences, University of Wuppertal, Wuppertal, Germany
| | - Michael Stiboller
- Department of Food Chemistry, Institute of Nutritional Science, University of Potsdam, Nuthetal, Germany
| | - Tania Schwerdtle
- Department of Food Chemistry, Institute of Nutritional Science, University of Potsdam, Nuthetal, Germany
| | - Deok-Soo Son
- Department of Biochemistry and Cancer Biology, Meharry Medical College, Nashville, Tennessee, USA
| | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine Bronx, New York, New York, USA
| | - Eunsook Lee
- Department of Pharmaceutical Sciences, Florida A&M University, Tallahassee, Florida, USA.
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14
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Li S, Selkoe DJ. A mechanistic hypothesis for the impairment of synaptic plasticity by soluble Aβ oligomers from Alzheimer's brain. J Neurochem 2020; 154:583-597. [PMID: 32180217 PMCID: PMC7487043 DOI: 10.1111/jnc.15007] [Citation(s) in RCA: 176] [Impact Index Per Article: 35.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Revised: 02/28/2020] [Accepted: 03/02/2020] [Indexed: 12/18/2022]
Abstract
It is increasingly accepted that early cognitive impairment in Alzheimer's disease results in considerable part from synaptic dysfunction caused by the accumulation of a range of oligomeric assemblies of amyloid β-protein (Aβ). Most studies have used synthetic Aβ peptides to explore the mechanisms of memory deficits in rodent models, but recent work suggests that Aβ assemblies isolated from human (AD) brain tissue are far more potent and disease-relevant. Although reductionist experiments show Aβ oligomers to impair synaptic plasticity and neuronal viability, the responsible mechanisms are only partly understood. Glutamatergic receptors, GABAergic receptors, nicotinic receptors, insulin receptors, the cellular prion protein, inflammatory mediators, and diverse signaling pathways have all been suggested. Studies using AD brain-derived soluble Aβ oligomers suggest that only certain bioactive forms (principally small, diffusible oligomers) can disrupt synaptic plasticity, including by binding to plasma membranes and changing excitatory-inhibitory balance, perturbing mGluR, PrP, and other neuronal surface proteins, down-regulating glutamate transporters, causing glutamate spillover, and activating extrasynaptic GluN2B-containing NMDA receptors. We synthesize these emerging data into a mechanistic hypothesis for synaptic failure in Alzheimer's disease that can be modified as new knowledge is added and specific therapeutics are developed.
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Affiliation(s)
- Shaomin Li
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
| | - Dennis J Selkoe
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
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15
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Neuron-Derived Estrogen Is Critical for Astrocyte Activation and Neuroprotection of the Ischemic Brain. J Neurosci 2020; 40:7355-7374. [PMID: 32817249 PMCID: PMC7534920 DOI: 10.1523/jneurosci.0115-20.2020] [Citation(s) in RCA: 77] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Revised: 07/09/2020] [Accepted: 07/15/2020] [Indexed: 02/08/2023] Open
Abstract
17β-Estradiol (E2) is produced from androgens via the action of the enzyme aromatase. E2 is known to be made in neurons in the brain, but the functions of neuron-derived E2 in the ischemic brain are unclear. Here, we used a forebrain neuron-specific aromatase KO (FBN-ARO-KO) mouse model to deplete neuron-derived E2 in the forebrain and determine its roles after global cerebral ischemia. We demonstrated that ovariectomized female FBN-ARO-KO mice exhibited significantly attenuated astrocyte activation, astrocytic aromatization, and decreased hippocampal E2 levels compared with FLOX mice. Furthermore, FBN-ARO-KO mice had exacerbated neuronal damage and worse cognitive dysfunction after global cerebral ischemia. Similar results were observed in intact male mice. RNA-seq analysis revealed alterations in pathways and genes associated with astrocyte activation, neuroinflammation, and oxidative stress in FBN-ARO-KO mice. The compromised astrocyte activation in FBN-ARO-KO mice was associated with robust downregulation of the astrocyte-derived neurotrophic factors, BDNF and IGF-1, as well as the astrocytic glutamate transporter, GLT-1. Νeuronal FGF2, which acts in a paracrine manner to suppress astrocyte activation, was increased in FBN-ARO-KO neurons. Interestingly, blocking FGF2 signaling by central injection of FGFR3-neutralizing antibody was able to reverse the diminishment in neuroprotective astrocyte reactivity, and attenuate neuronal damage in FBN-ARO-KO mice. Moreover, in vivo E2 replacement suppressed FGF2 signaling and rescued the compromised reactive astrogliosis and cognitive deficits. Collectively, our data provide novel genetic evidence for a beneficial role of neuron-derived E2 in astrocyte activation, neuroprotection, and cognitive preservation following ischemic injury to the brain. SIGNIFICANCE STATEMENT Following cerebral ischemia, astrocytes become highly reactive and can exert neuroprotection through the release of neurotrophic factors and clearance of neurotoxic glutamate. The current study advances our understanding of this process by demonstrating that neuron-derived 17β-estradiol (E2) is neuroprotective and critical for induction of reactive astrocytes and their ability to produce astrocyte-derived neurotrophic factors, BDNF and IGF-1, and the glutamate transporter, GLT-1 after ischemic brain damage. These beneficial effects of neuron-derived E2 appear to be due, at least in part, to suppression of neuronal FGF2 signaling, which is a known suppressor of astrocyte activation. These findings suggest that neuron-derived E2 is neuroprotective after ischemic brain injury via a mechanism that involves suppression of neuronal FGF2 signaling, thereby facilitating astrocyte activation.
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16
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Effects of Ischemia-Reperfusion on Tubular Cell Membrane Transporters and Consequences in Kidney Transplantation. J Clin Med 2020; 9:jcm9082610. [PMID: 32806541 PMCID: PMC7464608 DOI: 10.3390/jcm9082610] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 07/31/2020] [Accepted: 08/06/2020] [Indexed: 12/12/2022] Open
Abstract
Ischemia-reperfusion (IR)-induced acute kidney injury (IRI) is an inevitable event in kidney transplantation. It is a complex pathophysiological process associated with numerous structural and metabolic changes that have a profound influence on the early and the late function of the transplanted kidney. Proximal tubular cells are particularly sensitive to IRI. These cells are involved in renal and whole-body homeostasis, detoxification processes and drugs elimination by a transporter-dependent, transcellular transport system involving Solute Carriers (SLCs) and ATP Binding Cassettes (ABCs) transporters. Numerous studies conducted mainly in animal models suggested that IRI causes decreased expression and activity of some major tubular transporters. This could favor uremic toxins accumulation and renal metabolic alterations or impact the pharmacokinetic/toxicity of drugs used in transplantation. It is of particular importance to understand the underlying mechanisms and effects of IR on tubular transporters in order to improve the mechanistic understanding of IRI pathophysiology, identify biomarkers of graft function or promote the design and development of novel and effective therapies. Modulation of transporters’ activity could thus be a new therapeutic opportunity to attenuate kidney injury during IR.
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17
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Transport rate of EAAT2 is regulated by amino acid located at the interface between the scaffolding and substrate transport domains. Neurochem Int 2020; 139:104792. [PMID: 32668264 DOI: 10.1016/j.neuint.2020.104792] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 05/19/2020] [Accepted: 06/21/2020] [Indexed: 01/24/2023]
Abstract
Excitatory Amino Acid Transporters (EAATs) are plasma membrane proteins responsible for maintenance of low extracellular concentrations of glutamate in the CNS. Dysfunction in their activity is implicated in various neurological disorders. Glutamate transport by EAATs occurs through the movement of the central transport domain relative to the scaffold domain in the EAAT membrane protein. Previous studies suggested that residues located within the interface of these two domains in EAAT2, the main subtype of glutamate transporter in the brain, are involved in regulating transport rates. We used mutagenesis, structure-function relationship, surface protein expression and electrophysiology studies, in transfected COS-7 cells and oocytes, to examine residue glycine at position 298, which is located within this interface. Mutation G298A results in increased transport rate without changes in surface expression, suggesting a more hydrophobic and larger alanine results in facilitated transport movement. The increased transport rate does not involve changes in sodium affinity. Electrophysiological currents show that G298A increase both transport and anion currents, suggesting faster transitions through the transport cycle. This work identifies a region critically involved in setting the glutamate transport rate.
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18
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Fachim HA, Guizzo R, Cunha AOS, Pereira AC, Anjos LC, Mortari MR, Santos WF. Ceftriaxone pretreatment confers neuroprotection in rats with acute glaucoma and reduces the score of seizures induced by pentylenotetrazole in mice. J Biochem Mol Toxicol 2020; 34:e22578. [DOI: 10.1002/jbt.22578] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Revised: 05/01/2020] [Accepted: 06/23/2020] [Indexed: 12/27/2022]
Affiliation(s)
- Helene A. Fachim
- Neurobiology and Venoms Laboratory, Department of Biology, FFCLRP University of São Paulo São Paulo Brazil
- Instituto de Neurociências e Comportamento de Ribeirão Preto—INeC Ribeirão Preto São Paulo Brazil
| | - Renato Guizzo
- Instituto de Neurociências e Comportamento de Ribeirão Preto—INeC Ribeirão Preto São Paulo Brazil
| | - Alexandra O. S. Cunha
- Neurobiology and Venoms Laboratory, Department of Biology, FFCLRP University of São Paulo São Paulo Brazil
- Instituto de Neurociências e Comportamento de Ribeirão Preto—INeC Ribeirão Preto São Paulo Brazil
| | - Adriana C. Pereira
- Neurobiology and Venoms Laboratory, Department of Biology, FFCLRP University of São Paulo São Paulo Brazil
- Instituto de Neurociências e Comportamento de Ribeirão Preto—INeC Ribeirão Preto São Paulo Brazil
| | - Lilian C. Anjos
- Neuropharmacology Laboratory, Department of Physiological Sciences University of Brasília‐UnB Brasília Brazil
| | - Márcia R. Mortari
- Neuropharmacology Laboratory, Department of Physiological Sciences University of Brasília‐UnB Brasília Brazil
| | - Wagner F. Santos
- Neurobiology and Venoms Laboratory, Department of Biology, FFCLRP University of São Paulo São Paulo Brazil
- Instituto de Neurociências e Comportamento de Ribeirão Preto—INeC Ribeirão Preto São Paulo Brazil
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19
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Forster YM, Green JL, Khatiwada A, Liberato JL, Narayana Reddy PA, Salvino JM, Bienz S, Bigler L, dos Santos WF, Karklin Fontana AC. Elucidation of the Structure and Synthesis of Neuroprotective Low Molecular Mass Components of the Parawixia bistriata Spider Venom. ACS Chem Neurosci 2020; 11:1573-1596. [PMID: 32343555 DOI: 10.1021/acschemneuro.0c00007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The South American social spider Parawixia bistriata produces a venom containing complex organic compounds with intriguing biological activities. The crude venom leads to paralysis in termites and stimulates l-glutamate uptake and inhibits GABA uptake in rat brain synaptosomes. Glutamate is the major neurotransmitter at the insect neuromuscular junction and at the mammalian central nervous system, suggesting a modulation of the glutamatergic system by the venom. Parawixin1, 2, and 10 (Pwx1, 2 and 10) are HPLC fractions that demonstrate this bioactivity. Pwx1 stimulates l-glutamate uptake through the main transporter in the brain, EAAT2, and is neuroprotective in in vivo glaucoma models. Pxw2 inhibits GABA and glycine uptake in synaptosomes and inhibits seizures and neurodegeneration, and Pwx10 increases l-glutamate uptake in synaptosomes and is neuroprotective and anticonvulsant, shown in in vivo epilepsy models. Herein, we investigated the low molecular mass compounds in this venom and have found over 20 small compounds and 36 unique acylpolyamines with and without amino acid linkers. The active substances in fractions Pwx1 and Pwx2 require further investigation. We elucidated and confirmed the structure of the active acylpolyamine in Pwx10. Both fraction Pwx10 and the synthesized component enhance the activity of transporters EAAT1 and EAAT2, and, importantly, offer in vitro neuroprotection against excitotoxicity in primary cultures. These data suggest that compounds with this mechanism could be developed into therapies for disorders in which l-glutamate excitotoxicity is involved.
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Affiliation(s)
- Yvonne M. Forster
- Department of Chemistry, University of Zurich, Zurich, CH 8057, Switzerland
| | - Jennifer Leigh Green
- Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102, United States
| | - Apeksha Khatiwada
- Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102, United States
| | - José Luiz Liberato
- Department of Biology, University of São Paulo, Ribeirão Preto, SP 14040-900, Brazil
| | | | - Joseph M. Salvino
- The Wistar Institute, Philadelphia, Pennsylvania 19104, United States
| | - Stefan Bienz
- Department of Chemistry, University of Zurich, Zurich, CH 8057, Switzerland
| | - Laurent Bigler
- Department of Chemistry, University of Zurich, Zurich, CH 8057, Switzerland
| | | | - Andréia Cristina Karklin Fontana
- Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102, United States
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20
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Smaga I, Fierro D, Mesa J, Filip M, Knackstedt LA. Molecular changes evoked by the beta-lactam antibiotic ceftriaxone across rodent models of substance use disorder and neurological disease. Neurosci Biobehav Rev 2020; 115:116-130. [PMID: 32485268 DOI: 10.1016/j.neubiorev.2020.05.016] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Revised: 05/06/2020] [Accepted: 05/26/2020] [Indexed: 02/06/2023]
Abstract
Ceftriaxone is a beta-lactam antibiotic that increases the expression of the major glutamate transporter, GLT-1. As such, ceftriaxone ameliorates symptoms across multiple rodent models of neurological diseases and substance use disorders. However, the mechanism behind GLT-1 upregulation is unknown. The present review synthesizes this literature in order to identify commonalities in molecular changes. We find that ceftriaxone (200 mg/kg for at least two days) consistently restores GLT-1 expression in multiple rodent models of neurological disease, especially when GLT-1 is decreased in the disease model. The same dose given to healthy/drug-naive rodents does not reliably upregulate GLT-1 in any brain region except the hippocampus. Increased GLT-1 expression does not consistently arise from transcriptional regulation, and is likely to be due to trafficking changes. In addition to altered transporter expression, ceftriaxone ameliorates neuropathologies (e.g. tau, amyloid beta, cell death) and aberrant protein expression associated with a number of neurological disease models. Taken together, these results indicate that ceftriaxone remains a strong candidate for treatment of multiple disorders in the clinic.
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Affiliation(s)
- Irena Smaga
- Maj Institute of Pharmacology Polish Academy of Sciences, Department of Drug Addiction Pharmacology, Smętna 12, PL, 31-343, Kraków, Poland
| | - Daniel Fierro
- Department of Psychology, University of Florida, 945 Center Dr., Gainesville, FL, 32611, USA
| | - Javier Mesa
- Department of Psychology, University of Florida, 945 Center Dr., Gainesville, FL, 32611, USA; Center for Addiction Research and Education, University of Florida, Gainesville, FL, 32611, USA
| | - Malgorzata Filip
- Maj Institute of Pharmacology Polish Academy of Sciences, Department of Drug Addiction Pharmacology, Smętna 12, PL, 31-343, Kraków, Poland
| | - Lori A Knackstedt
- Department of Psychology, University of Florida, 945 Center Dr., Gainesville, FL, 32611, USA; Center for Addiction Research and Education, University of Florida, Gainesville, FL, 32611, USA.
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21
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Fan S, Xian X, Li L, Yao X, Hu Y, Zhang M, Li W. Ceftriaxone Improves Cognitive Function and Upregulates GLT-1-Related Glutamate-Glutamine Cycle in APP/PS1 Mice. J Alzheimers Dis 2019; 66:1731-1743. [PMID: 30452416 DOI: 10.3233/jad-180708] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Alzheimer's disease (AD) is characterized by progressive impairment of learning, memory, and cognitive deficits. Glutamate is the major excitatory neurotransmitter in the central nervous system and plays an important role in learning, memory, and cognition. The homeostasis and reutilization of glutamate are dependent on astrocytic uptake by glutamate transporter-1 (GLT-1) and the subsequent glutamate-glutamine cycle. Increasing evidence showed impairments in GLT-1 expression and uptake activity and glutamate-glutamine cycle in AD. Ceftriaxone (Cef) has been reported to upregulate the expression and uptake of GLT-1. Therefore, the present study was undertaken to explore whether Cef can improve cognitive deficits of APP/PS1 mice in early stage of AD by upregulating GLT-1 expression, and then promoting the glutamate-glutamine cycle. It was shown that Cef treatment significantly alleviated the cognitive deficits measured by Morris water maze test and upregulated GLT-1 protein expression in the hippocampus of APP/PS1 mice. Particularly, the activity of glutamine synthetase (GS) and the protein expression of system N glutamine transporter 1 (SN1), which are the key factors involved in the glutamate-glutamine cycle, were significantly upregulated as well after the Cef treatment. Furthermore, inhibition of GLT-1 uptake activity by dihydrokainic acid, an inhibitor of GLT-1, blocked the Cef-induced improvement on the cognitive deficits, GS activity, and SN1 expression. The above results suggested that Cef could improve cognitive deficits of APP/PS1 mice in early stage of AD by upregulating the GLT-1 expression, GS activity, and SN1 expression, which would lead to stimulating the glutamate-glutamine cycle.
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Affiliation(s)
- ShuJuan Fan
- Department of Pathophysiology, Neuroscience Center, Hebei Medical University, Shijiazhuang, P.R. China
| | - XiaoHui Xian
- Department of Pathophysiology, Neuroscience Center, Hebei Medical University, Shijiazhuang, P.R. China
| | - Li Li
- Central Laboratory, The Second Hospital of Hebei Medical University, Shijiazhuang, P.R. China
| | - XiaoGuang Yao
- Department of Pathophysiology, Neuroscience Center, Hebei Medical University, Shijiazhuang, P.R. China
| | - YuYan Hu
- Department of Pathophysiology, Neuroscience Center, Hebei Medical University, Shijiazhuang, P.R. China
| | - Min Zhang
- Department of Pathophysiology, Neuroscience Center, Hebei Medical University, Shijiazhuang, P.R. China
| | - WenBin Li
- Department of Pathophysiology, Neuroscience Center, Hebei Medical University, Shijiazhuang, P.R. China.,Aging and Cognition Neuroscience Laboratory of Hebei Province, Shijiazhuang, P.R. China
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22
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Althobaiti YS, Almalki A, Alsaab H, Alsanie W, Gaber A, Alhadidi Q, Hardy AMG, Nasr A, Alzahrani O, Stary CM, Shah ZA. Pregabalin: Potential for Addiction and a Possible Glutamatergic Mechanism. Sci Rep 2019; 9:15136. [PMID: 31641170 PMCID: PMC6805907 DOI: 10.1038/s41598-019-51556-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Accepted: 09/30/2019] [Indexed: 11/16/2022] Open
Abstract
Drug addiction remains a prevalent and fatal disease worldwide that carries significant social and economic impacts. Recent reports suggest illicit pregabalin (Lyrica) use may be increasing among youth, however the addictive potential of pregabalin has not been well established. Drug seeking behavior and chronic drug use are associated with deficits in glutamate clearance and activation of postsynaptic glutamatergic receptors. In the current study, we investigated the abuse potential of pregabalin using conditioned place preference (CPP) paradigm. Different doses of pregabalin (30, 60, 90, and 120 mg/kg) were used to assess the seeking behavior in mice. Glutamate homeostasis is maintained by glutamate transporter type-1 (GLT-1), which plays a vital role in clearing the released glutamate from synapses and drug seeking behavior. Therefore, we investigated the role of glutamate in pregabalin-seeking behavior with ceftriaxone (CEF), a potent GLT-1 upregulator. Mice treated with pregabalin 60 and 90 mg/kg doses demonstrated drug seeking-like behavior, which was significantly blocked by CEF pretreatment. These results suggest that pregabalin-induced CPP was successfully modulated by CEF which could serve as a lead compound for developing treatment for pregabalin abuse.
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Affiliation(s)
- Yusuf S Althobaiti
- Taif University, College of Pharmacy, Department of Pharmacology and Toxicology, Taif, Saudi Arabia. .,Taif University, College of Pharmacy, Addiction and Neuroscience Research Unit, Taif, Saudi Arabia.
| | - Atiah Almalki
- Taif University, College of Pharmacy, Addiction and Neuroscience Research Unit, Taif, Saudi Arabia.,Taif University, College of Pharmacy, Department of Pharmaceutical chemistry, Taif, Saudi Arabia
| | - Hashem Alsaab
- Taif University, College of Pharmacy, Addiction and Neuroscience Research Unit, Taif, Saudi Arabia.,Taif University, College of Pharmacy, Department of Pharmaceutics and Pharmaceutical Technology, Taif, Saudi Arabia
| | - Walaa Alsanie
- Taif University, College of Pharmacy, Addiction and Neuroscience Research Unit, Taif, Saudi Arabia.,Taif University, Faculty of Applied Medical Sciences, Department of Clinical Laboratories Sciences, Taif, Saudi Arabia
| | - Ahmed Gaber
- Taif University, College of Pharmacy, Addiction and Neuroscience Research Unit, Taif, Saudi Arabia.,Taif University, Faculty of Sciences, Department of Biology, Taif, Saudi Arabia
| | - Qasim Alhadidi
- Department of Anesthesiology, Perioperative and Pain Medicine, Stanford Medical School, Stanford University, CA, USA
| | - Ana Maria Gregio Hardy
- Department of Physiology and Pharmacology, College of Medicine and Life Sciences, University of Toledo, OH, USA
| | - Abdulrahman Nasr
- Taif University, College of Pharmacy, Department of Pharmacology and Toxicology, Taif, Saudi Arabia
| | - Omar Alzahrani
- Taif University, College of Pharmacy, Department of Pharmacology and Toxicology, Taif, Saudi Arabia
| | - Creed M Stary
- Department of Anesthesiology, Perioperative and Pain Medicine, Stanford Medical School, Stanford University, CA, USA
| | - Zahoor A Shah
- Department of Medicinal and Biological Chemistry, College of Pharmacy and Pharmaceutical Sciences, University of Toledo, OH, USA
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23
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Siracusa R, Fusco R, Cuzzocrea S. Astrocytes: Role and Functions in Brain Pathologies. Front Pharmacol 2019; 10:1114. [PMID: 31611796 PMCID: PMC6777416 DOI: 10.3389/fphar.2019.01114] [Citation(s) in RCA: 218] [Impact Index Per Article: 36.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Accepted: 08/30/2019] [Indexed: 12/16/2022] Open
Abstract
Astrocytes are a population of cells with distinctive morphological and functional characteristics that differ within specific areas of the brain. Postnatally, astrocyte progenitors migrate to reach their brain area and related properties. They have a regulatory role of brain functions that are implicated in neurogenesis and synaptogenesis, controlling blood-brain barrier permeability and maintaining extracellular homeostasis. Mature astrocytes also express some genes enriched in cell progenitors, suggesting they can retain proliferative potential. Considering heterogeneity of cell population, it is not surprising that their disorders are related to a wide range of different neuro-pathologies. Brain diseases are characterized by the active inflammatory state of the astrocytes, which is usually described as up-regulation of glial fibrillary acidic protein (GFAP). In particular, the loss of astrocytes function as a result of cellular senescence could have implications for the neurodegenerative disorders, such as Alzheimer disease and Huntington disease, and for the aging brain. Astrocytes can also drive the induction and the progression of the inflammatory state due to their Ca2+ signals and that it is strongly related to the disease severity/state. Moreover, they contribute to the altered neuronal activity in several frontal cortex pathologies such as ischemic stroke and epilepsy. There, we describe the current knowledge pertaining to astrocytes' role in brain pathologies and discuss the possibilities to target them as approach toward pharmacological therapies for neuro-pathologies.
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Affiliation(s)
- Rosalba Siracusa
- Department of Chemical, Biological, Pharmaceutical and Environmental Science, University of Messina, Messina, Italy
| | - Roberta Fusco
- Department of Chemical, Biological, Pharmaceutical and Environmental Science, University of Messina, Messina, Italy
| | - Salvatore Cuzzocrea
- Department of Chemical, Biological, Pharmaceutical and Environmental Science, University of Messina, Messina, Italy.,Department of Pharmacological and Physiological Science, Saint Louis University School of Medicine, Saint Louis, MO, United States
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24
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Peng M, Ling X, Song R, Gao X, Liang Z, Fang F, Cang J. Upregulation of GLT-1 via PI3K/Akt Pathway Contributes to Neuroprotection Induced by Dexmedetomidine. Front Neurol 2019; 10:1041. [PMID: 31611842 PMCID: PMC6776610 DOI: 10.3389/fneur.2019.01041] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Accepted: 09/13/2019] [Indexed: 12/30/2022] Open
Abstract
Perioperative ischemic stroke usually leads to neurological dysfunction caused by neuron death. During the ischemic condition, excitotoxity due to extracellular glutamate accumulation is a main mechanism of neuron damage. The clearance of glutamate mainly depends on glutamate transporter-1 (GLT-1) which is expressed in astrocytes. Dexmedetomidine, an α2 adrenergic receptor agonist, is proved to induce neuroprotection. This study was set out to investigate the glutamate-related mechanism involved in the neuroprotective effect of dexmedetomidine. Middle cerebral artery occlusion (MCAO) was used as a model of ischemic stroke in our study. We determined Neurological deficit scores (NDS) and Magnetic resonance imaging (MRI) at three points (2, 6, and 24 h) after middle cerebral artery occlusion (MCAO) to evaluate the neuroprotective effect of dexmedetomidine. Besides, we performed western blot (6 and 24 h after MACO) and immunofluorescent staining (24 h after MCAO) to observe the expression of GLT-1. The effect and mechanism of dexmedetomidine on GLT-1 in primary cultured astrocytes were investigated using western blot and RT-PCR. Our results showed that pretreatment with dexmedetomidine improved NDS and reduced infarct volume as well as upregulating GLT-1 expression. Furthermore, using Atipamezole and LY294002, we found that dexmedetomidine significantly increased GLT-1 levels in astrocytes via activating α2 adrenergic receptor and PI3K/AKT pathway both in vitro and in vivo study. Overall, our present study indicated that dexmedetomidine had neuroprotective effects on ischemia stroke and upregulation of GLT-1 levels by PI3K/AKT dependent pathway might be the potential mechanism.
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Affiliation(s)
- Mengyuan Peng
- Department of Anesthesiology, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Xiaomin Ling
- Department of Anesthesiology, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Ruixue Song
- Department of Anesthesiology, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Xuan Gao
- Department of Anesthesiology, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Zhifeng Liang
- Comparative Nerve Imaging Study Group, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Fang Fang
- Department of Anesthesiology, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Jing Cang
- Department of Anesthesiology, Zhongshan Hospital, Fudan University, Shanghai, China
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25
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Falcucci RM, Wertz R, Green JL, Meucci O, Salvino J, Fontana ACK. Novel Positive Allosteric Modulators of Glutamate Transport Have Neuroprotective Properties in an in Vitro Excitotoxic Model. ACS Chem Neurosci 2019; 10:3437-3453. [PMID: 31257852 DOI: 10.1021/acschemneuro.9b00061] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Dysfunction of excitatory amino acid transporters (EAATs) has been implicated in the pathogenesis of various neurological disorders, such as stroke, brain trauma, epilepsy, and several neurodegenerative disorders. EAAT2 is the main transporter subtype responsible for glutamate clearance in the brain, and plays a key role in regulating neurotransmission and preventing excitotoxicity. Therefore, compounds that increase the activity of EAAT2 have therapeutic potential for neuroprotection. In previous studies, we used virtual screening approaches to identify novel positive allosteric modulators (PAMs) of EAAT2. These compounds were shown to selectively increase the activity of EAAT2 and increase Vmax of transport, without changing substrate affinity. In this work, our major effort was to investigate whether increasing the activity of EAAT2 by allosteric modulation would translate to neuroprotection in in vitro primary culture models of excitotoxicity. To investigate potential neuroprotective effects of one EAAT2 PAM, GT949, we subjected cultures to acute and prolonged excitotoxic insults by exogenous application of glutamate, or oxidative stress by application of hydrogen peroxide. GT949 administration did not result in neuroprotection in the oxidative stress model, likely due to damage of the glutamate transporters. However, GT949 displayed neuroprotective properties after acute and prolonged glutamate-mediated excitotoxicity. We propose that this compound prevents excess glutamate signaling by increasing the rate of glutamate clearance by EAAT2, thereby preventing excitotoxic damage and cell death. This novel class of compounds is therefore an innovative approach for neuroprotection with potential for translation in in vivo animal models of excitotoxicity.
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Affiliation(s)
- Romulo Martelli Falcucci
- Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102, United States
| | - Ryan Wertz
- Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102, United States
| | - Jennifer Leigh Green
- Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102, United States
| | - Olimpia Meucci
- Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102, United States
| | - Joseph Salvino
- The Wistar Institute, Philadelphia, Pennsylvania 19104, United States
| | - Andréia Cristina Karklin Fontana
- Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102, United States
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26
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Arundic acid administration protects astrocytes, recovers histological damage and memory deficits induced by neonatal hypoxia ischemia in rats. Int J Dev Neurosci 2019; 76:41-51. [DOI: 10.1016/j.ijdevneu.2019.06.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Revised: 05/16/2019] [Accepted: 06/12/2019] [Indexed: 11/17/2022] Open
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27
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Loewen JL, Albertini G, Dahle EJ, Sato H, Smolders IJ, Massie A, Wilcox KS. Genetic and pharmacological manipulation of glial glutamate transporters does not alter infection-induced seizure activity. Exp Neurol 2019; 318:50-60. [PMID: 31022385 DOI: 10.1016/j.expneurol.2019.04.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Revised: 03/19/2019] [Accepted: 04/20/2019] [Indexed: 12/11/2022]
Abstract
The contribution of glial transporters to glutamate movement across the membrane has been identified as a potential target for anti-seizure therapies. Two such glutamate transporters, GLT-1 and system xc-, are expressed on glial cells, and modulation of their expression and function have been identified as a means by which seizures, neuronal injury, and gliosis can be reduced in models of brain injury. While GLT-1 is responsible for the majority of glutamate uptake in the brain, system xc- releases glutamate in the extracellular cleft in exchange for cystine and represents as such the major source of hippocampal extracellular glutamate. Using the Theiler's Murine Encephalomyelitis Virus (TMEV) model of viral-induced epilepsy, we have taken two well-studied approaches, one pharmacological, one genetic, to investigate the potential role(s) of GLT-1 and system xc- in TMEV-induced pathology. Our findings suggest that the methods we utilized to modulate these glial transporters, while effective in other models, are not sufficient to reduce the number or severity of behavioral seizures in TMEV-infected mice. However, genetic knockout of xCT, the specific subunit of system xc-, may have cellular effects, as we observed a slight decrease in neuronal injury caused by TMEV and an increase in astrogliosis in the CA1 region of the hippocampus. Furthermore, xCT knockout caused an increase in GLT-1 expression selectively in the cortex. These findings have significant implications for both the characterization of the TMEV model as well as for future efforts to discover novel and effective anti-seizure drugs.
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Affiliation(s)
- Jaycie L Loewen
- Department of Pharmacology and Toxicology, University of Utah, USA; Interdepartmental Program in Neuroscience, University of Utah, USA
| | - Giulia Albertini
- Department of Pharmaceutical Chemistry, Drug Analysis and Drug Information, Center for Neurosciences (C4N), Vrije Universiteit Brussel, Belgium
| | - E Jill Dahle
- Department of Pharmacology and Toxicology, University of Utah, USA
| | - Hideyo Sato
- Department of Medical Technology, Niigata University, Japan
| | - Ilse J Smolders
- Department of Pharmaceutical Chemistry, Drug Analysis and Drug Information, Center for Neurosciences (C4N), Vrije Universiteit Brussel, Belgium
| | - Ann Massie
- Department of Pharmaceutical Biotechnology and Molecular Biology, C4N, Vrije Universiteit Brussel, Belgium
| | - Karen S Wilcox
- Department of Pharmacology and Toxicology, University of Utah, USA; Interdepartmental Program in Neuroscience, University of Utah, USA.
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28
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Liu X, Hong L, Peng W, Jiang J, Peng Z, Yang J. The Neuroprotective Effect of miR-181a After Oxygen-Glucose Deprivation/Reperfusion and the Associated Mechanism. J Mol Neurosci 2019; 68:261-274. [PMID: 30949956 DOI: 10.1007/s12031-019-01300-4] [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: 01/28/2019] [Accepted: 03/12/2019] [Indexed: 11/26/2022]
Abstract
The level of miR-181a decreases rapidly in N2a cells following oxygen-glucose deprivation/reperfusion, but its role in this process is unclear. Reelin, a regulator of neuronal migration and synaptogenesis, is a predicted target of miR-181a. We hypothesized that miR-181a reduces neuronal apoptosis and protects neurons by targeting reelin. Second mitochondria-derived activator of caspases (Smac) is a protein located in mitochondria that regulates apoptosis. The pro-apoptotic effect of Smac is achieved by reversing the effects of apoptosis-inhibiting proteins (IAPs), particularly X-linked inhibitor of apoptosis (XIAP). We also evaluated the effect of miR-181a on the Smac/IAP signaling pathway after oxygen-glucose deprivation and reperfusion in N2a cells. The miR-181a level, apoptosis rate, and the levels of reelin mRNA and protein, Smac, and XIAP were assessed in N2a cells subjected to oxygen-glucose deprivation for 4 h and reperfusion for 0, 4, 12, or 24 h with/without an miR-181a mimic, or mismatched control. Direct targeting of reelin by miR-181a was assessed in vitro by dual luciferase assay and immunoblotting. Pre-treatment with miR-181a mimicked the increase in the miR-181a level in N2a cells after oxygen-glucose deprivation/reperfusion, resulting in a significant decrease in the apoptosis rate. Changes in the miR-181a level in N2a cells were inversely correlated with reelin protein expression. Direct targeting of the reelin 3' untranslated region by miR-181a was verified by dual luciferase assay, which showed that miR-181a significantly inhibited luciferase activity. The Smac level was significantly lower in the miR-181a mimics than the normal control and mimics-cont groups (P < 0.01), whereas the level of XIAP was increased slightly. These findings suggest that miR-181a protects neurons from apoptosis by inhibiting reelin expression and regulating the Smac/IAP signaling pathway after oxygen-glucose deprivation/reperfusion injury.
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Affiliation(s)
- Xiangyu Liu
- Department of Neurology, Hunan Provincial People's Hospital, Nanhua University, No.61 Jiefang west road, Changsha, 410005, Hunan, China
| | - Lou Hong
- Department of Neurosurgery, The First Affiliated Hospital of Nanchang University, Nanchang University, Nanchang, 330006, Jiangxi, China
| | - Wenjuan Peng
- Department of Neurology, Hunan Provincial People's Hospital, Nanhua University, No.61 Jiefang west road, Changsha, 410005, Hunan, China
| | - Jun Jiang
- Department of Neurology, Hunan Provincial People's Hospital, Nanhua University, No.61 Jiefang west road, Changsha, 410005, Hunan, China
| | - Zhe Peng
- Department of Neurology, Hunan Provincial People's Hospital, Nanhua University, No.61 Jiefang west road, Changsha, 410005, Hunan, China
| | - Jianwen Yang
- Department of Neurology, Hunan Provincial People's Hospital, Nanhua University, No.61 Jiefang west road, Changsha, 410005, Hunan, China.
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Zhang LN, Hao L, Guo YS, Wang HY, Li LL, Liu LZ, Li WB. Are glutamate transporters neuroprotective or neurodegenerative during cerebral ischemia? J Mol Med (Berl) 2019; 97:281-289. [PMID: 30675649 DOI: 10.1007/s00109-019-01745-5] [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: 10/03/2018] [Revised: 01/10/2019] [Accepted: 01/14/2019] [Indexed: 12/14/2022]
Abstract
The accumulation of glutamate (Glu) in the synaptic cleft during cerebral ischemia triggers the death of neurons, causing mental or physical handicap. However, the mechanisms of the alteration in Glu homeostasis and the imbalance between the release and clearance of Glu in ischemia are not yet completely understood. Additionally, the role of Glu transporters in regulating Glu concentration in the synaptic cleft is controversial. This review aims to provide readers with an in-depth understanding of Glu transporters in the early or later stages of ischemic events, or in mild or severe cerebral ischemia via alteration of Glu transporter expression, reversal of Glu transporters function, and trafficking between membrane and cytoplasm, to further clarify whether the Glu transporters are neuroprotective or neurodegenerative during cerebral ischemia. We provide the insights for deeper understanding of the mechanism of Glu transporters regulation after different periods and severities of cerebral ischemia.
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Affiliation(s)
- Li-Nan Zhang
- Department of Pathophysiology, Hebei Medical University, 361 Zhongshan East Road, Shijiazhuang, 050017, Hebei, China
| | - Liang Hao
- Department of Neurosurgery, Third Hospital of Shijiazhuang, Beijing, 050011, Hebei, China
| | - Yu-Song Guo
- Department of Traumatology, Third Hospital of Shijiazhuang, Beijing, 050011, Hebei, China
| | - Hai-Yan Wang
- Pharmaceutical Preparation Section, Third Hospital of Shijiazhuang, Beijing, 050011, Hebei, China
| | - Lin-Lin Li
- Clinical Medicine, College of Basic Medicine, Hebei Medical University, Beijing, 050017, Hebei, China
| | - Li-Zhe Liu
- Department of Pathophysiology, Hebei Medical University, 361 Zhongshan East Road, Shijiazhuang, 050017, Hebei, China
| | - Wen-Bin Li
- Department of Pathophysiology, Hebei Medical University, 361 Zhongshan East Road, Shijiazhuang, 050017, Hebei, China.
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30
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Alotaibi G, Rahman S. Effects of glial glutamate transporter activator in formalin‐induced pain behaviour in mice. Eur J Pain 2018. [DOI: https://doi.org/10.1002/ejp.1343] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Ghallab Alotaibi
- Department of Pharmaceutical Sciences, College of Pharmacy South Dakota State University Brookings South Dakota
| | - Shafiqur Rahman
- Department of Pharmaceutical Sciences, College of Pharmacy South Dakota State University Brookings South Dakota
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31
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Alotaibi G, Rahman S. Effects of glial glutamate transporter activator in formalin-induced pain behaviour in mice. Eur J Pain 2018; 23:765-783. [PMID: 30427564 DOI: 10.1002/ejp.1343] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Revised: 11/02/2018] [Accepted: 11/08/2018] [Indexed: 12/22/2022]
Abstract
BACKGROUND Nociceptive pain remains a prevalent clinical problem and often poorly responsive to the currently available analgesics. Previous studies have shown that astroglial glutamate transporter-1 (GLT-1) in the hippocampus and anterior cingulate cortex (ACC) is critically involved in pain processing and modulation. However, the role of astroglial GLT-1 in nociceptive pain involving the hippocampus and ACC remains unknown. We investigated the role of 3-[[(2-Methylphenyl) methyl]thio]-6-(2-pyridinyl)-pyridazine (LDN-212320), a GLT-1 activator, in nociceptive pain model and hippocampal-dependent behavioural tasks in mice. METHODS We evaluated the effects of LDN-212320 in formalin-induced nociceptive pain model. In addition, formalin-induced impaired hippocampal-dependent behaviours were measured using Y-maze and object recognition test. Furthermore, GLT-1 expression and extracellular signal-regulated kinase phosphorylation (pERK1/2) were measured in the hippocampus and ACC using Western blot analysis and immunohistochemistry. RESULTS The LDN-212320 (10 or 20 mg/kg, i.p) significantly attenuated formalin-evoked nociceptive behaviour. The antinociceptive effects of LDN-212320 were reversed by systemic administration of DHK (10 mg/kg, i.p), a GLT-1 antagonist. Moreover, LDN-212320 (10 or 20 mg/kg, i.p) significantly reversed formalin-induced impaired hippocampal-dependent behaviour. In addition, LDN-212320 (10 or 20 mg/kg, i.p) increased GLT-1 expressions in the hippocampus and ACC. On the other hand, LDN-212320 (20 mg/kg, i.p) significantly reduced formalin induced-ERK phosphorylation, a marker of nociception, in the hippocampus and ACC. CONCLUSION These results suggest that the GLT-1 activator LDN-212320 prevents nociceptive pain by upregulating astroglial GLT-1 expression in the hippocampus and ACC. Therefore, GLT-1 activator could be a novel drug candidate for nociceptive pain. SIGNIFICANCE The present study provides new insights and evaluates the role of GLT-1 activator in the modulation of nociceptive pain involving hippocampus and ACC. Here, we provide evidence that GLT-1 activator could be a potential therapeutic utility for the treatment of nociceptive pain.
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Affiliation(s)
- Ghallab Alotaibi
- Department of Pharmaceutical Sciences, College of Pharmacy, South Dakota State University, Brookings, South Dakota
| | - Shafiqur Rahman
- Department of Pharmaceutical Sciences, College of Pharmacy, South Dakota State University, Brookings, South Dakota
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32
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Li K, Zhou H, Zhan L, Shi Z, Sun W, Liu D, Liu L, Liang D, Tan Y, Xu W, Xu E. Hypoxic Preconditioning Maintains GLT-1 Against Transient Global Cerebral Ischemia Through Upregulating Cx43 and Inhibiting c-Src. Front Mol Neurosci 2018; 11:344. [PMID: 30323740 PMCID: PMC6172853 DOI: 10.3389/fnmol.2018.00344] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Accepted: 09/03/2018] [Indexed: 01/06/2023] Open
Abstract
Transient global cerebral ischemia (tGCI) causes excessive release of glutamate from neurons. Astrocytic glutamate transporter-1 (GLT-1) and glutamine synthetase (GS) together play a predominant role in maintaining glutamate at normal extracellular concentrations. Though our previous studies reported the alleviation of tGCI-induced neuronal death by hypoxic preconditioning (HPC) in hippocampal Cornu Ammonis 1 (CA1) of adult rats, the underlying mechanism has not yet been fully elaborated. In this study, we aimed to investigate the roles of GLT-1 and GS in the neuroprotection mediated by HPC against tGCI and to ascertain whether these roles can be regulated by connexin 43 (Cx43) and cellular-Src (c-Src) activity. We found that HPC decreased the level of extracellular glutamate in CA1 after tGCI via maintenance of GLT-1 expression and GS activity. Inhibition of GLT-1 expression with dihydrokainate (DHK) or inhibition of GS activity with methionine sulfoximine (MSO) abolished the neuroprotection induced by HPC. Also, HPC markedly upregulated Cx43 and inhibited p-c-Src expression in CA1 after tGCI, whereas inhibition of Cx43 with Gap26 dramatically reversed this effect. Furthermore, inhibition of p-c-Src with 4-amino-5-(4-chlorophenyl)-7-(t-butyl) pyrazolo (3, 4-d) pyrimidine (PP2) decreased c-Src activity, increased protein levels of GLT-1 and Cx43, enhanced GS activity, and thus reduced extracellular glutamate level in CA1 after tGCI. Collectively, our data demonstrated that reduced extracellular glutamate induced by HPC against tGCI through preventing the reduction of GLT-1 expression and maintaining GS activity in hippocampal CA1, which was mediated by upregulating Cx43 expression and inhibiting c-Src activity.
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Affiliation(s)
- Kongping Li
- Institute of Neurosciences and Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical University and Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou, China
| | - Huarong Zhou
- Institute of Neurosciences and Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical University and Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou, China
| | - Lixuan Zhan
- Institute of Neurosciences and Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical University and Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou, China
| | - Zhe Shi
- Institute of Neurosciences and Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical University and Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou, China
| | - Weiwen Sun
- Institute of Neurosciences and Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical University and Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou, China
| | - Dandan Liu
- Institute of Neurosciences and Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical University and Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou, China
| | - Liu Liu
- Institute of Neurosciences and Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical University and Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou, China
| | - Donghai Liang
- Department of Environmental Health Sciences, Rollins School of Public Health, Emory University, Atlanta, GA, United States
| | - Yafu Tan
- Institute of Neurosciences and Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical University and Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou, China.,Department of Neurology, The First Affiliated Hospital of Guangxi Medical University, Nanning, China
| | - Wensheng Xu
- Institute of Neurosciences and Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical University and Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou, China
| | - En Xu
- Institute of Neurosciences and Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical University and Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou, China
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33
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Foster JB, Zhao F, Wang X, Xu Z, Lin K, Askwith CC, Hodgetts KJ, Lin CLG. Pyridazine-derivatives Enhance Structural and Functional Plasticity of Tripartite Synapse Via Activation of Local Translation in Astrocytic Processes. Neuroscience 2018; 388:224-238. [PMID: 30056115 DOI: 10.1016/j.neuroscience.2018.07.028] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Revised: 06/19/2018] [Accepted: 07/17/2018] [Indexed: 12/19/2022]
Abstract
Excitatory amino acid transporter 2 (EAAT2) is primarily located in perisynaptic astrocytic processes (PAP) where it plays a critical role in synaptic glutamate homeostasis. Dysregulation of EAAT2 at the translational level has been implicated in a myriad of neurological diseases. We previously discovered that pyridazine analogs can activate EAAT2 translation. Here, we sought to further refine the site and mechanism of compound action. We found that in vivo, compound treatment increased EAAT2 expression only in the PAP of astrocytes where EAAT2 mRNA also was identified. Direct application of compound to isolated PAP induced de novo EAAT2 protein synthesis, indicating that compound activates translation locally in the PAP. Using a screening process, we identified a set of PAP proteins that are rapidly up-regulated following compound treatment and a subset of these PAP proteins may be locally synthesized in the PAP. Importantly, these identified proteins are associated with the structural and functional capacity of the PAP, indicating compound enhanced plasticity of the PAP. Concomitantly, we found that pyridazine analogs increase synaptic protein expression in the synapse and enhance hippocampal long-term potentiation. This was not dependent upon compound-mediated local translation in neurons. This suggests that compound enhances the structural and functional capacity of the PAP which in turn facilitates enhanced plasticity of the tripartite synapse. Overall, this provides insight into the mechanism action site of pyridazine derivatives as well as the growing appreciation of the dynamic regulation and functional aspects of the PAP at the tripartite synapse.
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Affiliation(s)
- Joshua B Foster
- Department of Neuroscience, College of Medicine, The Ohio State University, Columbus, OH, United States
| | - Fangli Zhao
- Department of Neuroscience, College of Medicine, The Ohio State University, Columbus, OH, United States
| | - Xueqin Wang
- Department of Neuroscience, College of Medicine, The Ohio State University, Columbus, OH, United States
| | - Zan Xu
- Department of Neuroscience, College of Medicine, The Ohio State University, Columbus, OH, United States
| | - Kuanhung Lin
- Department of Neuroscience, College of Medicine, The Ohio State University, Columbus, OH, United States
| | - Candice C Askwith
- Department of Neuroscience, College of Medicine, The Ohio State University, Columbus, OH, United States
| | - Kevin J Hodgetts
- Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Cambridge, MA, United States
| | - Chien-Liang Glenn Lin
- Department of Neuroscience, College of Medicine, The Ohio State University, Columbus, OH, United States.
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34
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Paternò R, Chillon JM. Potentially Common Therapeutic Targets for Multiple Sclerosis and Ischemic Stroke. Front Physiol 2018; 9:855. [PMID: 30057552 PMCID: PMC6053536 DOI: 10.3389/fphys.2018.00855] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Accepted: 06/15/2018] [Indexed: 12/21/2022] Open
Abstract
Ischemic stroke (IS) and multiple sclerosis (MS) are two pathologies of the central nervous system (CNS). At the first look, this appears to be the only similarity between the two diseases, as they seem quite different. Indeed IS has an acute onset compared to MS which develops chronically; IS is consecutive to blood clot migrating to cerebral blood vessels or decrease in cerebral blood flow following atherosclerosis or decreases in cardiac output, whereas MS is an immune disease associated with neurodegeneration. However, both pathologies share similar pathologic pathways and treatments used in MS have been the object of studies in IS. In this mini-review we will discuss similarities between IS and MS on astrocytes and neuroinflammation hallmarks emphasizing the potential for treatments.
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Affiliation(s)
- Roberto Paternò
- Dipartimento di Medicina Clinica e Chirurgia, Università degli Studi di Napoli Federico II, Naples, Italy
| | - Jean-Marc Chillon
- Mécanismes Physiopathologiques et Conséquences des Calcifications Cardiovasculaires (EA 7517), Faculty of Pharmacy, University of Picardie Jules Verne, Amiens, France.,Direction de la Recherche Clinique et de l'Innovation, CHU Amiens Picardie, Amiens, France
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35
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Cheng Z, Ou Y, Zhang L, Zhang P, Yuan X, Peng W, Wang S, Zhu X, Zhang L, Meng Y. The glutamate clearance function of adipose stromal cells-derived astrocytes. Neurosci Lett 2018; 677:94-102. [PMID: 29704575 DOI: 10.1016/j.neulet.2018.04.048] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2017] [Accepted: 04/24/2018] [Indexed: 10/17/2022]
Abstract
ADSCs-derived astrocytes qualify the morphology, ultrastructure and membrane electrical potential, which are all unique to astrocytes. But whether they have the glutamate clearance function like mature astrocytes is under exploration. ADSCs were extracted, cultured and induced into astrocytes for 48 h, 7d, 14d and 21d in vitro. Inverted phase contrast microscope was used to observe the morphology of the cells in each group. Immunocytochemistry assay, immunofluorescence assay and Western blotting were used to detect the expression of GFAP, EAAT2 and GS of the cells in each group. The cells were cultured in glutamate solution for 1, 2, 3 and 4 h respectively before the solution collected. The glutamate concentration of the solution was detected using Glutamate Colorimetric Assay Hit. ADSCs-derived astrocytes expressed GFAP, EAAT2 and GS, all of which increased gradually and reached peak when induced for 14 days. In induction for 48 h, 7d and 14d groups, the extracellular glutamate concentration decreased gradually during the cells cultured in glutamate solution for 1, 2, 3 and 4 h, among which the decrease extent was most prominent in 14d group, while the extracellular glutamate concentration had no change in uninduction and induction for 21d group. ADSCs-derived astrocytes expressed EAAT2 and GS, meanwhile had the function of clearing glutamate, which was prominent when induced into astrocytes for 7-14 days.
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Affiliation(s)
- Zanzan Cheng
- Department of Neurology, Affiliated Kailuan General Hospital of North China University of Science and Technology, Tangshan 063000, Hebei Province, China
| | - Ya Ou
- Department of Neurology, Affiliated Kailuan General Hospital of North China University of Science and Technology, Tangshan 063000, Hebei Province, China
| | - Lili Zhang
- Department of Neurology, Affiliated Kailuan General Hospital of North China University of Science and Technology, Tangshan 063000, Hebei Province, China
| | - Pingshu Zhang
- Key Laboratory of Neurological and Biological Function of Hebei Province, Tangshan 063000, Hebei Province, China; Key Laboratory of Neurology of Tangshan, Tangshan 063000, Hebei Province, China
| | - Xiaodong Yuan
- Department of Neurology, Affiliated Kailuan General Hospital of North China University of Science and Technology, Tangshan 063000, Hebei Province, China; Key Laboratory of Neurological and Biological Function of Hebei Province, Tangshan 063000, Hebei Province, China.
| | - Wei Peng
- Department of Neurology, Affiliated Kailuan General Hospital of North China University of Science and Technology, Tangshan 063000, Hebei Province, China
| | - Shujuan Wang
- Department of Neurology, Affiliated Kailuan General Hospital of North China University of Science and Technology, Tangshan 063000, Hebei Province, China
| | - Xuhong Zhu
- Department of Neurology, Affiliated Kailuan General Hospital of North China University of Science and Technology, Tangshan 063000, Hebei Province, China
| | - Liping Zhang
- Department of Neurology, Affiliated Kailuan General Hospital of North China University of Science and Technology, Tangshan 063000, Hebei Province, China
| | - Yan Meng
- Department of Neurology, Affiliated Kailuan General Hospital of North China University of Science and Technology, Tangshan 063000, Hebei Province, China
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36
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Kortagere S, Mortensen OV, Xia J, Lester W, Fang Y, Srikanth Y, Salvino JM, Fontana ACK. Identification of Novel Allosteric Modulators of Glutamate Transporter EAAT2. ACS Chem Neurosci 2018; 9:522-534. [PMID: 29140675 DOI: 10.1021/acschemneuro.7b00308] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Dysfunction of excitatory amino acid transporters (EAATs) has been implicated in the pathogenesis of various neurological disorders, such as stroke, brain trauma, epilepsy, and neurodegenerative diseases, among others. EAAT2 is the main subtype responsible for glutamate clearance in the brain, having a key role in regulating transmission and preventing excitotoxicity. Therefore, compounds that increase the expression or activity of EAAT2 have therapeutic potential for neuroprotection. Previous studies identified molecular determinants for EAAT2 transport stimulation in a structural domain that lies at the interface of the rigid trimerization domain and the central substrate binding transport domain. In this work, a hybrid structure based approach was applied, based on this molecular domain, to create a high-resolution pharmacophore. Subsequently, virtual screening of a library of small molecules was performed, identifying 10 hit molecules that interact at the proposed domain. Among these, three compounds were determined to be activators, four were inhibitors, and three had no effect on EAAT2-mediated transport in vitro. Further characterization of the two best ranking EAAT2 activators for efficacy, potency, and selectivity for glutamate over monoamine transporters subtypes and NMDA receptors and for efficacy in cultured astrocytes is demonstrated. Mutagenesis studies suggest that the EAAT2 activators interact with residues forming the interface between the trimerization and transport domains. These compounds enhance the glutamate translocation rate, with no effect on substrate interaction, suggesting an allosteric mechanism. The identification of these novel positive allosteric modulators of EAAT2 offers an innovative approach for the development of therapies based on glutamate transport enhancement.
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Affiliation(s)
- Sandhya Kortagere
- Department of Microbiology and Immunology, Centers for Molecular Parasitology, Virology and Translational Neuroscience, Institute for Molecular Medicine, Drexel University College of Medicine, Philadelphia, Pennsylvania 19129, United States
| | - Ole V. Mortensen
- Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102, United States
| | - Jingsheng Xia
- Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102, United States
| | - William Lester
- Analytical Chemistry, Division of Pre-Clinical Innovation (DPI), NCATS, National Institutes of Health, Rockville, Maryland 20850, United States
| | - Yuhong Fang
- Analytical Chemistry, Division of Pre-Clinical Innovation (DPI), NCATS, National Institutes of Health, Rockville, Maryland 20850, United States
| | - Yellamelli Srikanth
- Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102, United States
| | - Joseph M. Salvino
- Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102, United States
| | - Andréia C. K. Fontana
- Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102, United States
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37
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Kim AY, Baik EJ. Glutamate Dehydrogenase as a Neuroprotective Target Against Neurodegeneration. Neurochem Res 2018; 44:147-153. [PMID: 29357018 DOI: 10.1007/s11064-018-2467-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Revised: 01/03/2018] [Accepted: 01/05/2018] [Indexed: 10/18/2022]
Abstract
Regulation of glutamate metabolism via glutamate dehydrogenase (GDH) might be the promising therapeutic approach for treating neurodegenerative disorders. In the central nervous system, glutamate functions both as a major excitatory neurotransmitter and as a key intermediate metabolite for neurons. GDH converts glutamate to α-ketoglutarate, which serves as a TCA cycle intermediate. Dysregulated GDH activity in the central nervous system is highly correlated with neurological disorders. Indeed, studies conducted with mutant mice and allosteric drugs have shown that deficient or overexpressed GDH activity in the brain can regulate whole body energy metabolism and affect early onset of Parkinson's disease, Alzheimer's disease, temporal lobe epilepsy, and spinocerebellar atrophy. Moreover, in strokes with excitotoxicity as the main pathophysiology, mice that overexpressed GDH exhibited smaller ischemic lesion than mice with normal GDH expression. In additions, GDH activators improve lesions in vivo by increasing α-ketoglutarate levels. In neurons exposed to an insult in vitro, enhanced GDH activity increases ATP levels. Thus, in an energy crisis, neuronal mitochondrial activity is improved and excitotoxic risk is reduced. Consequently, modulating GDH activity in energy-depleted conditions could be a sound strategy for maintaining the mitochondrial factory in neurons, and thus, protect against metabolic failure.
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Affiliation(s)
- A Young Kim
- Department of Physiology, Ajou University School of Medicine, Suwon, 16499, South Korea.,Chronic Inflammatory Disease Research Center, Ajou University School of Medicine, Suwon, 16499, South Korea
| | - Eun Joo Baik
- Department of Physiology, Ajou University School of Medicine, Suwon, 16499, South Korea. .,Chronic Inflammatory Disease Research Center, Ajou University School of Medicine, Suwon, 16499, South Korea.
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38
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Krzyżanowska W, Pomierny B, Bystrowska B, Pomierny-Chamioło L, Filip M, Budziszewska B, Pera J. Ceftriaxone- and N-acetylcysteine-induced brain tolerance to ischemia: Influence on glutamate levels in focal cerebral ischemia. PLoS One 2017; 12:e0186243. [PMID: 29045497 PMCID: PMC5646803 DOI: 10.1371/journal.pone.0186243] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Accepted: 09/27/2017] [Indexed: 01/22/2023] Open
Abstract
One of the major players in the pathophysiology of cerebral ischemia is disrupted homeostasis of glutamatergic neurotransmission, resulting in elevated extracellular glutamate (Glu) concentrations and excitotoxicity-related cell death. In the brain, Glu concentrations are regulated by Glu transporters, including Glu transporter-1 (GLT-1) and cystine/Glu antiporter (system xc-). Modulation of these transporters by administration of ceftriaxone (CEF, 200 mg/kg, i.p.) or N-acetylcysteine (NAC, 150 mg/kg, i.p.) for 5 days before focal cerebral ischemia may induce brain tolerance to ischemia by significantly limiting stroke-related damage and normalizing Glu concentrations. In the present study, focal cerebral ischemia was induced by 90-minute middle cerebral artery occlusion (MCAO). We compared the effects of CEF and NAC pretreatment on Glu concentrations in extracellular fluid and cellular-specific expression of GLT-1 and xCT with the effects of two reference preconditioning methods, namely, ischemic preconditioning and chemical preconditioning in rats. Both CEF and NAC significantly reduced Glu levels in the frontal cortex and hippocampus during focal cerebral ischemia, and this decrease was comparable with the Glu level achieved with the reference preconditioning strategies. The results of immunofluorescence staining of GLT-1 and xCT on astrocytes, neurons and microglia accounted for the observed changes in extracellular Glu levels to a certain extent. Briefly, after MCAO, the expression of GLT-1 on astrocytes decreased, but pretreatment with CEF seemed to prevent this downregulation. In addition, every intervention used in this study seemed to reduce xCT expression on astrocytes and neurons. The results of this study indicate that modulation of Glu transporter expression may restore Glu homeostasis. Moreover, our results suggest that CEF and NAC may induce brain tolerance to ischemia by influencing GLT-1 and system xc- expression levels. These transporters are presumably good targets for the development of novel therapies for brain ischemia.
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Affiliation(s)
- Weronika Krzyżanowska
- Department of Biochemical Toxicology, Faculty of Pharmacy, Jagiellonian University Medical College, Kraków, Poland
| | - Bartosz Pomierny
- Department of Biochemical Toxicology, Faculty of Pharmacy, Jagiellonian University Medical College, Kraków, Poland
- * E-mail:
| | - Beata Bystrowska
- Department of Toxicology, Faculty of Pharmacy, Jagiellonian University Medical College, Krakow, Poland
| | - Lucyna Pomierny-Chamioło
- Department of Toxicology, Faculty of Pharmacy, Jagiellonian University Medical College, Krakow, Poland
| | - Małgorzata Filip
- Institute of Pharmacology, Polish Academy of Sciences, Laboratory of Drug Addiction Pharmacology, Kraków, Poland
| | - Bogusława Budziszewska
- Department of Biochemical Toxicology, Faculty of Pharmacy, Jagiellonian University Medical College, Kraków, Poland
| | - Joanna Pera
- Department of Neurology, Faculty of Medicine, Jagiellonian University Medical College, Krakow, Poland
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39
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Drugs to Alter Extracellular Concentration of Glutamate: Modulators of Glutamate Uptake Systems. ACTA ACUST UNITED AC 2017. [DOI: 10.1007/978-1-4939-7228-9_7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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40
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Neuroprotective effects of ceftriaxone treatment on cognitive and neuronal deficits in a rat model of accelerated senescence. Behav Brain Res 2017; 330:8-16. [DOI: 10.1016/j.bbr.2017.05.002] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Revised: 04/26/2017] [Accepted: 05/02/2017] [Indexed: 12/11/2022]
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41
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Ceftriaxone-mediated upregulation of the glutamate transporter GLT-1 contrasts neurotoxicity evoked by kainate in rat organotypic spinal cord cultures. Neurotoxicology 2017; 60:34-41. [DOI: 10.1016/j.neuro.2017.02.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Revised: 02/01/2017] [Accepted: 02/27/2017] [Indexed: 12/13/2022]
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42
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Shi Z, Zhang W, Lu Y, Lu Y, Xu L, Fang Q, Wu M, Jia M, Wang Y, Dong L, Yan X, Yang S, Yuan F. Aquaporin 4-Mediated Glutamate-Induced Astrocyte Swelling Is Partially Mediated through Metabotropic Glutamate Receptor 5 Activation. Front Cell Neurosci 2017; 11:116. [PMID: 28503134 PMCID: PMC5408017 DOI: 10.3389/fncel.2017.00116] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Accepted: 04/07/2017] [Indexed: 12/17/2022] Open
Abstract
Astrocytes are one of the most abundant cell types in the mammalian central nervous system (CNS), and astrocyte swelling is the primary event associated with brain edema. Glutamate, the principal excitatory amino acid neurotransmitter in the CNS, is released at high levels after brain injury including cerebral ischemia. This leads to astrocyte swelling, which we previously demonstrated is related to metabotropic glutamate receptor (mGluR) activation. Aquaporin 4 (AQP4), the predominant water channel in the brain, is expressed in astrocyte endfeet and plays an important role in brain edema following ischemia. Studies recently showed that mGluR5 is also expressed on astrocytes. Therefore, it is worth investigating whether AQP4 mediates the glutamate-induced swelling of astrocytes via mGluR5. In the present study, we found that 1 mM glutamate induced astrocyte swelling, quantified by the cell perimeter, but it had no effect on astrocyte viability measured by the cell counting kit-8 (CCK-8) and lactate dehydrogenase (LDH) assays. Quantitative reverse transcription polymerase chain reaction analyses revealed that AQP4, among AQP1, 4, 5, 9 and 11, was the main molecular expressed in cultured astrocytes. Glutamate-induced cell swelling was accompanied by a concentration-dependent change in AQP4 expression. Furthermore, RNAi technology revealed that AQP4 gene silencing inhibited glutamate-induced astrocyte swelling. Moreover, we found that mGluR5 expression was greatest among the mGluRs in cultured astrocytes and was co-expressed with AQP4. Activation of mGluR5 in cultured astrocytes using (S)-3,5-dihydroxyphenylglycine (DHPG), an mGluR5 agonist, mimicked the effect of glutamate. This effect was abolished by co-incubation with the mGluR5 antagonist fenobam but was not influenced by DL-threo-β-benzyloxyaspartic acid (DL-TBOA), a glutamate transporter inhibitor. Finally, experiments in a rat model of transient middle cerebral artery occlusion (tMCAO) revealed that co-expression of mGluR5 and AQP4 was increased in astrocyte endfeet around capillaries in the penumbra, and this was accompanied by brain edema. Collectively, these results suggest that glutamate induces cell swelling and alters AQP4 expression in astrocytes via mGluR5 activation, which may provide a novel approach for the treatment of edema following brain injury.
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Affiliation(s)
- Zhongfang Shi
- Department of Pathophysiology, Beijing Neurosurgical Institute, Beijing Tiantan Hospital, Capital Medical UniversityBeijing, China.,China National Clinical Research Center for Neurological DiseasesBeijing, China.,Beijing Key Laboratory of Central Nervous System InjuryBeijing, China.,Center of Stroke, Beijing Institute for Brain DisordersBeijing, China.,Beijing Key Laboratory of Translational Medicine for Cerebrovascular DiseaseBeijing, China
| | - Wei Zhang
- Department of Pathophysiology, Beijing Neurosurgical Institute, Beijing Tiantan Hospital, Capital Medical UniversityBeijing, China.,China National Clinical Research Center for Neurological DiseasesBeijing, China.,Beijing Key Laboratory of Central Nervous System InjuryBeijing, China.,Center of Stroke, Beijing Institute for Brain DisordersBeijing, China.,Beijing Key Laboratory of Translational Medicine for Cerebrovascular DiseaseBeijing, China
| | - Yang Lu
- Department of Pathophysiology, Beijing Neurosurgical Institute, Beijing Tiantan Hospital, Capital Medical UniversityBeijing, China.,China National Clinical Research Center for Neurological DiseasesBeijing, China.,Beijing Key Laboratory of Central Nervous System InjuryBeijing, China.,Center of Stroke, Beijing Institute for Brain DisordersBeijing, China.,Beijing Key Laboratory of Translational Medicine for Cerebrovascular DiseaseBeijing, China
| | - Yi Lu
- Department of Pathophysiology, Beijing Neurosurgical Institute, Beijing Tiantan Hospital, Capital Medical UniversityBeijing, China.,China National Clinical Research Center for Neurological DiseasesBeijing, China.,Beijing Key Laboratory of Central Nervous System InjuryBeijing, China.,Center of Stroke, Beijing Institute for Brain DisordersBeijing, China.,Beijing Key Laboratory of Translational Medicine for Cerebrovascular DiseaseBeijing, China
| | - Lixin Xu
- Department of Pathophysiology, Beijing Neurosurgical Institute, Beijing Tiantan Hospital, Capital Medical UniversityBeijing, China.,China National Clinical Research Center for Neurological DiseasesBeijing, China.,Beijing Key Laboratory of Central Nervous System InjuryBeijing, China.,Center of Stroke, Beijing Institute for Brain DisordersBeijing, China.,Beijing Key Laboratory of Translational Medicine for Cerebrovascular DiseaseBeijing, China
| | - Qing Fang
- Department of Pathophysiology, Beijing Neurosurgical Institute, Beijing Tiantan Hospital, Capital Medical UniversityBeijing, China.,China National Clinical Research Center for Neurological DiseasesBeijing, China.,Beijing Key Laboratory of Central Nervous System InjuryBeijing, China.,Center of Stroke, Beijing Institute for Brain DisordersBeijing, China.,Beijing Key Laboratory of Translational Medicine for Cerebrovascular DiseaseBeijing, China
| | - Min Wu
- Department of Pathophysiology, Beijing Neurosurgical Institute, Beijing Tiantan Hospital, Capital Medical UniversityBeijing, China.,China National Clinical Research Center for Neurological DiseasesBeijing, China.,Beijing Key Laboratory of Central Nervous System InjuryBeijing, China.,Center of Stroke, Beijing Institute for Brain DisordersBeijing, China.,Beijing Key Laboratory of Translational Medicine for Cerebrovascular DiseaseBeijing, China
| | - Mei Jia
- Department of Pathophysiology, Beijing Neurosurgical Institute, Beijing Tiantan Hospital, Capital Medical UniversityBeijing, China.,China National Clinical Research Center for Neurological DiseasesBeijing, China.,Beijing Key Laboratory of Central Nervous System InjuryBeijing, China.,Center of Stroke, Beijing Institute for Brain DisordersBeijing, China.,Beijing Key Laboratory of Translational Medicine for Cerebrovascular DiseaseBeijing, China
| | - Yujiao Wang
- Department of Pathophysiology, Beijing Neurosurgical Institute, Beijing Tiantan Hospital, Capital Medical UniversityBeijing, China.,China National Clinical Research Center for Neurological DiseasesBeijing, China.,Beijing Key Laboratory of Central Nervous System InjuryBeijing, China.,Center of Stroke, Beijing Institute for Brain DisordersBeijing, China.,Beijing Key Laboratory of Translational Medicine for Cerebrovascular DiseaseBeijing, China
| | - Liping Dong
- Department of Pathophysiology, Beijing Neurosurgical Institute, Beijing Tiantan Hospital, Capital Medical UniversityBeijing, China.,China National Clinical Research Center for Neurological DiseasesBeijing, China.,Beijing Key Laboratory of Central Nervous System InjuryBeijing, China.,Center of Stroke, Beijing Institute for Brain DisordersBeijing, China.,Beijing Key Laboratory of Translational Medicine for Cerebrovascular DiseaseBeijing, China
| | - Xu Yan
- Department of Pathophysiology, Beijing Neurosurgical Institute, Beijing Tiantan Hospital, Capital Medical UniversityBeijing, China.,China National Clinical Research Center for Neurological DiseasesBeijing, China.,Beijing Key Laboratory of Central Nervous System InjuryBeijing, China.,Center of Stroke, Beijing Institute for Brain DisordersBeijing, China.,Beijing Key Laboratory of Translational Medicine for Cerebrovascular DiseaseBeijing, China
| | - Shaohua Yang
- Department of Pathophysiology, Beijing Neurosurgical Institute, Beijing Tiantan Hospital, Capital Medical UniversityBeijing, China.,China National Clinical Research Center for Neurological DiseasesBeijing, China.,Beijing Key Laboratory of Central Nervous System InjuryBeijing, China.,Center of Stroke, Beijing Institute for Brain DisordersBeijing, China.,Beijing Key Laboratory of Translational Medicine for Cerebrovascular DiseaseBeijing, China.,Department of Pharmacology and Neuroscience, University of North Texas Health Science CenterFort Worth, TX, USA
| | - Fang Yuan
- Department of Pathophysiology, Beijing Neurosurgical Institute, Beijing Tiantan Hospital, Capital Medical UniversityBeijing, China.,China National Clinical Research Center for Neurological DiseasesBeijing, China.,Beijing Key Laboratory of Central Nervous System InjuryBeijing, China.,Center of Stroke, Beijing Institute for Brain DisordersBeijing, China.,Beijing Key Laboratory of Translational Medicine for Cerebrovascular DiseaseBeijing, China
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Yu P, Guan L, Zhou L, Guo J, Guo R, Lin R, Ding W, Li X, Liu W. Upregulation of glutamate metabolism by BYHWD in cultured astrocytes following oxygen-glucose deprivation/reoxygenation in part depends on the activation of p38 MAPK. Exp Ther Med 2017; 13:3089-3096. [PMID: 28587384 DOI: 10.3892/etm.2017.4330] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Accepted: 01/26/2017] [Indexed: 11/06/2022] Open
Abstract
Recent studies have demonstrated that Buyang Huanwu Decoction (BYHWD) decreased glutamate levels subsequent to cerebral ischemia. Glutamate transporter-1 (GLT-1) and glutamine synthetase (GS), which are located in astrocytes, mainly contribute to glutamate transportation, thus reducing glutamate concentration. BYHWD has previously been demonstrated to upregulate GLT-1 and GS following ischemia in vivo. However, whether BYHWD can directly influence astrocytic GLT-1/GS levels remains unknown. In the present study, the effect of BYHWD containing serum (BYHWD-CS) on GLT-1/GS levels in astrocytes following oxygen-glucose deprivation/reoxygenation (OGD/R) was investigated. The results revealed that BYHWD-CS enhanced the expression levels of GLT-1 and GS in cultured astrocytes, which reduced glutamate concentration in the culture medium. Meanwhile, increased p38 mitogen-activated protein kinase (p38 MAPK) was phosphorylated (activation form) by BYHWD-CS in cultured astrocytes, and the specific p38 inhibitor SB203580 blocked the increase of GLT-1/GS accompanied by decreased cell viability. Furthermore, SB203580 suppressed the effect of BYHWD-CS on the level of glial fibrillary acidic protein (an astrocytic marker), thus confirming that astrocytes are directly involved in the protective role of BYHWD after OGD/R. These findings suggest that BYHWD upregulates GLT-1 and GS via p38 MAPK activation, and protects cultured astrocytes from death caused by OGD/R (typical in vitro model), which complemented the role of astrocytes in the protective effect of BYHWD.
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Affiliation(s)
- Peng Yu
- Department of Physiology, College of Fundamental Medical Science, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong 510006, P.R. China
| | - Li Guan
- Department of Physiology, College of Fundamental Medical Science, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong 510006, P.R. China
| | - Lequan Zhou
- Department of Physiology, College of Fundamental Medical Science, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong 510006, P.R. China
| | - Jianchao Guo
- Department of Physiology, College of Fundamental Medical Science, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong 510006, P.R. China
| | - Ruixian Guo
- Department of Physiology, Zhongshan Medical College, Sun Yat-sen University, Guangzhou, Guangdong 510080, P.R. China
| | - Ruishan Lin
- Department of Physiology, College of Fundamental Medical Science, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong 510006, P.R. China
| | - Wenting Ding
- Department of Physiology, College of Fundamental Medical Science, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong 510006, P.R. China
| | - Xiaoying Li
- Department of Physiology, College of Fundamental Medical Science, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong 510006, P.R. China
| | - Wei Liu
- Department of Physiology, College of Fundamental Medical Science, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong 510006, P.R. China
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Zhou ZQ, Li YL, Ao ZB, Wen ZL, Chen QW, Huang ZG, Xiao B, Yan XH. Baicalin protects neonatal rat brains against hypoxic-ischemic injury by upregulating glutamate transporter 1 via the phosphoinositide 3-kinase/protein kinase B signaling pathway. Neural Regen Res 2017; 12:1625-1631. [PMID: 29171427 PMCID: PMC5696843 DOI: 10.4103/1673-5374.217335] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Baicalin is a flavonoid compound extracted from Scutellaria baicalensis root. Recent evidence indicates that baicalin is neuroprotective in models of ischemic stroke. Here, we investigate the neuroprotective effect of baicalin in a neonatal rat model of hypoxic-ischemic encephalopathy. Seven-day-old pups underwent left common carotid artery ligation followed by hypoxia (8% oxygen at 37°C) for 2 hours, before being injected with baicalin (120 mg/kg intraperitoneally) and examined 24 hours later. Baicalin effectively reduced cerebral infarct volume and neuronal loss, inhibited apoptosis, and upregulated the expression of p-Akt and glutamate transporter 1. Intracerebroventricular injection of the phosphoinositide 3-kinase/protein kinase B (PI3K/Akt) inhibitor LY294002 30 minutes before injury blocked the effect of baicalin on p-Akt and glutamate transporter 1, and weakened the associated neuroprotective effect. Our findings provide the first evidence, to our knowledge that baicalin can protect neonatal rat brains against hypoxic-ischemic injury by upregulating glutamate transporter 1 via the PI3K/Akt signaling pathway.
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Affiliation(s)
- Zhi-Qing Zhou
- Department of Pediatrics, the Second People's Hospital of Huaihua City, Huaihua, Hunan Province, China
| | - Yong-Liang Li
- Department of Oncology, the Second People's Hospital of Huaihua City, Huaihua, Hunan Province, China
| | - Zhen-Bo Ao
- Department of Pediatrics, the Second People's Hospital of Huaihua City, Huaihua, Hunan Province, China
| | - Zhi-Li Wen
- Department of Gastroenterology, the Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi Province, China
| | - Qi-Wen Chen
- Department of Pediatrics, the First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi Province, China
| | - Zheng-Gang Huang
- Department of Pediatrics, the First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi Provi nce, China
| | - Bing Xiao
- Department of Neurosurgery, the Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi Province, China
| | - Xiao-Hua Yan
- Department of Pediatrics, the First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi Province, China
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45
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Shi J, Jiang K, Li Z. Involvement of spinal glutamate transporter-1 in the development of mechanical allodynia and hyperalgesia associated with type 2 diabetes. J Pain Res 2016; 9:1121-1129. [PMID: 27932896 PMCID: PMC5135479 DOI: 10.2147/jpr.s118412] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Little is known about the effects of the development of type 2 diabetes on glutamate homeostasis in the spinal cord. Therefore, we quantified the extracellular levels of glutamate in the spinal cord of Zucker diabetic fatty (ZDF) rats using in vivo microdialysis. In addition, protein levels of glutamate transporter-1 (GLT-1) in the spinal cord of ZDF rats were measured using Western blot. Finally, the effects of repeated intrathecal injections of ceftriaxone, which was previously shown to enhance GLT-1 expression, on the development of mechanical allodynia and hyperalgesia as well as on basal extracellular level of glutamate and the expression of GLT-1 in the spinal cord of ZDF rats were evaluated. It was found that ZDF rats developed mechanical hyperalgesia and allodynia, which were associated with increased basal extracellular levels of glutamate and attenuated levels of GLT-1 expression in the spinal cord, particularly in the dorsal horn. Furthermore, repeated intrathecal administrations of ceftriaxone dose-dependently prevented the development of mechanical hyperalgesia and allodynia in ZDF rats, which were correlated with enhanced GLT-1 expression without altering the basal glutamate levels in the spinal cord of ZDF rats. Overall, the results suggested that impaired glutamate reuptake in the spinal cord may contribute to the development of neuropathic pains in type 2 diabetes.
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Affiliation(s)
- Jinshan Shi
- Department of Anesthesiology, Guizhou Provincial People's Hospital
| | - Ke Jiang
- Department of Anesthesiology, The Affiliated Hospital of Guizhou Medical University, Guiyang
| | - Zhaoduan Li
- Department of Anesthesiology, Tianjin Nankai Hospital, Tianjin, People's Republic of China
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Kim AY, Jeong KH, Lee JH, Kang Y, Lee SH, Baik EJ. Glutamate dehydrogenase as a neuroprotective target against brain ischemia and reperfusion. Neuroscience 2016; 340:487-500. [PMID: 27845178 DOI: 10.1016/j.neuroscience.2016.11.007] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Revised: 11/02/2016] [Accepted: 11/06/2016] [Indexed: 01/13/2023]
Abstract
Deregulation of glutamate homeostasis is associated with degenerative neurological disorders. Glutamate dehydrogenase (GDH) is important for glutamate metabolism and plays a central role in expanding the pool of tricarboxylic acid (TCA) cycle intermediate alpha-ketoglutarate (α-KG), which improves overall bioenergetics. Under high energy demand, maintenance of ATP production results in functionally active mitochondria. Here, we tested whether the modulation of GDH activity can rescue ischemia/reperfusion-induced neuronal death in an in vivo mouse model of middle artery occlusion and an in vitro oxygen/glucose depletion model. Iodoacetate, an inhibitor of glycolysis, was also used in a model of energy failure, remarkably depleting ATP and α-KG. To stimulate GDH activity, the GDH activator 2-aminobicyclo-(2,2,1)-heptane-2-carboxylic acid and potential activator beta-lapachone were used. The GDH activators restored α-KG and ATP levels in the injury models and provided potent neuroprotection. We also found that beta-lapachone increased glutamate utilization, accompanied by a reduction in extracellular glutamate. Thus, our hypothesis that mitochondrial GDH activators increase α-KG production as an alternative energy source for use in the TCA cycle under energy-depleted conditions was confirmed. Our results suggest that increasing GDH-mediated glutamate oxidation represents a new therapeutic intervention for neurodegenerative disorders, including stoke.
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Affiliation(s)
- A Young Kim
- Department of Physiology, Ajou University School of Medicine, Suwon 16499, Republic of Korea; Chronic Inflammatory Disease Research Center, Ajou University School of Medicine, Suwon 16499, Republic of Korea
| | - Kyeong-Hoon Jeong
- Gachon University of Medicine and Science, Incheon 406-840, Republic of Korea
| | - Jae Ho Lee
- Department of Biochemistry, Ajou University School of Medicine, Suwon 16499, Republic of Korea
| | - Yup Kang
- Chronic Inflammatory Disease Research Center, Ajou University School of Medicine, Suwon 16499, Republic of Korea
| | - Soo Hwan Lee
- Department of Physiology, Ajou University School of Medicine, Suwon 16499, Republic of Korea
| | - Eun Joo Baik
- Department of Physiology, Ajou University School of Medicine, Suwon 16499, Republic of Korea; Chronic Inflammatory Disease Research Center, Ajou University School of Medicine, Suwon 16499, Republic of Korea.
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Hefendehl JK, LeDue J, Ko RWY, Mahler J, Murphy TH, MacVicar BA. Mapping synaptic glutamate transporter dysfunction in vivo to regions surrounding Aβ plaques by iGluSnFR two-photon imaging. Nat Commun 2016; 7:13441. [PMID: 27834383 PMCID: PMC5114608 DOI: 10.1038/ncomms13441] [Citation(s) in RCA: 99] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2016] [Accepted: 10/04/2016] [Indexed: 12/22/2022] Open
Abstract
Amyloid-β (Aβ) plaques, a hallmark of Alzheimer's disease (AD), are surrounded by regions of neuronal and glial hyperactivity. We use in vivo two-photon and wide-field imaging of the glutamate sensor iGluSnFR to determine whether pathological changes in glutamate dynamics in the immediate vicinity of Aβ deposits in APPPS1 transgenic mice could alter neuronal activity in this microenvironment. In regions close to Aβ plaques chronic states of high spontaneous glutamate fluctuations are observed and the timing of glutamate responses evoked by sensory stimulation exhibit slower decay rates in two cortical brain areas. GLT-1 expression is reduced around Aβ plaques and upregulation of GLT-1 expression and activity by ceftriaxone partially restores glutamate dynamics to values in control regions. We conclude that the toxic microenvironment surrounding Aβ plaques results, at least partially, from enhanced glutamate levels and that pharmacologically increasing GLT-1 expression and activity may be a new target for early therapeutic intervention. In Alzheimer's disease (AD), neural hyperactivity has been shown to occur in the regions surrounding Aβ plaques. Here, the authors use in vivo two-photon imaging in mouse models of AD and report abnormal glutamate dynamics in the vicinity of plaques which can be partially restored via GLT-1 upregulation through Ceftriaxone treatment.
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Affiliation(s)
- J K Hefendehl
- Djavad Mowafaghian Centre for Brain Health, Faculty of Medicine, University of British Columbia, 2211 Wesbrook Mall, Vancouver, British Columbia, Canada V6T 1Z3
| | - J LeDue
- Djavad Mowafaghian Centre for Brain Health, Faculty of Medicine, University of British Columbia, 2211 Wesbrook Mall, Vancouver, British Columbia, Canada V6T 1Z3
| | - R W Y Ko
- Djavad Mowafaghian Centre for Brain Health, Faculty of Medicine, University of British Columbia, 2211 Wesbrook Mall, Vancouver, British Columbia, Canada V6T 1Z3
| | - J Mahler
- Hertie-Institut für klinische Hirnforschung, Otfried-Müller-Strasse 27, 72076 Tübingen, Germany
| | - T H Murphy
- Djavad Mowafaghian Centre for Brain Health, Faculty of Medicine, University of British Columbia, 2211 Wesbrook Mall, Vancouver, British Columbia, Canada V6T 1Z3
| | - B A MacVicar
- Djavad Mowafaghian Centre for Brain Health, Faculty of Medicine, University of British Columbia, 2211 Wesbrook Mall, Vancouver, British Columbia, Canada V6T 1Z3
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Huff CL, Morano RL, Herman JP, Yamamoto BK, Gudelsky GA. MDMA decreases glutamic acid decarboxylase (GAD) 67-immunoreactive neurons in the hippocampus and increases seizure susceptibility: Role for glutamate. Neurotoxicology 2016; 57:282-290. [PMID: 27773601 DOI: 10.1016/j.neuro.2016.10.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Revised: 10/17/2016] [Accepted: 10/18/2016] [Indexed: 01/15/2023]
Abstract
3,4-Methylenedioxy-methamphetamine (MDMA) is a unique psychostimulant that continues to be a popular drug of abuse. It has been well documented that MDMA reduces markers of 5-HT axon terminals in rodents, as well as humans. A loss of parvalbumin-immunoreactive (IR) interneurons in the hippocampus following MDMA treatment has only been documented recently. In the present study, we tested the hypothesis that MDMA reduces glutamic acid decarboxylase (GAD) 67-IR, another biochemical marker of GABA neurons, in the hippocampus and that this reduction in GAD67-IR neurons and an accompanying increase in seizure susceptibility involve glutamate receptor activation. Repeated exposure to MDMA (3×10mg/kg, ip) resulted in a reduction of 37-58% of GAD67-IR cells in the dentate gyrus (DG), CA1, and CA3 regions, as well as an increased susceptibility to kainic acid-induced seizures, both of which persisted for at least 30days following MDMA treatment. Administration of the NMDA antagonist MK-801 or the glutamate transporter type 1 (GLT-1) inducer ceftriaxone prevented both the MDMA-induced loss of GAD67-IR neurons and the increased vulnerability to kainic acid-induced seizures. The MDMA-induced increase in the extracellular concentration of glutamate in the hippocampus was significantly diminished in rats treated with ceftriaxone, thereby implicating a glutamatergic mechanism in the neuroprotective effects of ceftriaxone. In summary, the present findings support a role for increased extracellular glutamate and NMDA receptor activation in the MDMA-induced loss of hippocampal GAD67-IR neurons and the subsequent increased susceptibility to evoked seizures.
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Affiliation(s)
- Courtney L Huff
- Division of Pharmaceutical Sciences, University of Cincinnati-James Winkle College of Pharmacy, Cincinnati, OH 45267, United States
| | - Rachel L Morano
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati-College of Medicine, Cincinnati, OH, 45219, United States
| | - James P Herman
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati-College of Medicine, Cincinnati, OH, 45219, United States
| | - Bryan K Yamamoto
- Department of Pharmacology and Toxicology, Indiana University-School of Medicine, Indianapolis, IN 46202, United States
| | - Gary A Gudelsky
- Division of Pharmaceutical Sciences, University of Cincinnati-James Winkle College of Pharmacy, Cincinnati, OH 45267, United States.
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Guan Y, Liu X, Su Y. Ceftriaxone pretreatment reduces the propensity of postpartum depression following stroke during pregnancy in rats. Neurosci Lett 2016; 632:15-22. [PMID: 27558732 DOI: 10.1016/j.neulet.2016.08.036] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Revised: 08/12/2016] [Accepted: 08/20/2016] [Indexed: 01/11/2023]
Abstract
OBJECTIVE Ischemic stroke increases the propensity to develop depression in humans and laboratory animals, and we hypothesized that such an incidence during pregnancy may increase the risk for the development of postpartum depression (PPD). MATERIALS AND METHODS To test this hypothesis, we used bilateral common carotid arteries occlusion (BCCAO) to induce transient cerebral ischemia in pregnant rats, and evaluated its effects on subsequent development of PPD in dams. Additionally, we investigated whether ceftriaxone pretreatments before the induction of brain ischemia could alter the propensity of PPD. RESULTS We found that 15min BCCAO during pregnancy enhanced immobility time and reduced the frequency of swimming or climbing behaviors in the forced swim test, and decreased the sucrose preference in dams at postpartum day 21. Such behavioral alterations were associated with lower level of GLT-1 expression in the medial prefrontal cortical regions (mPFC) of PPD dams. Specifically, mPFC GLT-1 expression levels in dams with ischemia history were correlated with sucrose preference levels at postpartum day 21. Finally, ceftriaxone pretreatment (200mg/kg/day, 5days) before the 15min BCCAO prevented the development of PPD, and prevented the reduction of GLT-1 expression in the mPFC. CONCLUSIONS Taken together, our results suggested that ceftriaxone pretreatment before brain ischemia during pregnancy may reduce the propensity for the development of PPD by preventing the loss of GLT-1 expression in the mPFC.
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Affiliation(s)
- Yonghong Guan
- Department of Obstetrics and Gynecology, The Second Hospital of Jilin University, Changchun, China
| | - Xianying Liu
- Department of Medical Affairs, The Second Hospital of Jilin University, Changchun, China
| | - Yuetian Su
- Department of Neurosurgery, The Second Hospital of Jilin University, No. 218, Ziqiang Road, Changchun 130041, China.
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50
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David CN, Frias ES, Szu JI, Vieira PA, Hubbard JA, Lovelace J, Michael M, Worth D, McGovern KE, Ethell IM, Stanley BG, Korzus E, Fiacco TA, Binder DK, Wilson EH. GLT-1-Dependent Disruption of CNS Glutamate Homeostasis and Neuronal Function by the Protozoan Parasite Toxoplasma gondii. PLoS Pathog 2016; 12:e1005643. [PMID: 27281462 PMCID: PMC4900626 DOI: 10.1371/journal.ppat.1005643] [Citation(s) in RCA: 107] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Accepted: 04/28/2016] [Indexed: 01/09/2023] Open
Abstract
The immune privileged nature of the CNS can make it vulnerable to chronic and latent infections. Little is known about the effects of lifelong brain infections, and thus inflammation, on the neurological health of the host. Toxoplasma gondii is a parasite that can infect any mammalian nucleated cell with average worldwide seroprevalence rates of 30%. Infection by Toxoplasma is characterized by the lifelong presence of parasitic cysts within neurons in the brain, requiring a competent immune system to prevent parasite reactivation and encephalitis. In the immunocompetent individual, Toxoplasma infection is largely asymptomatic, however many recent studies suggest a strong correlation with certain neurodegenerative and psychiatric disorders. Here, we demonstrate a significant reduction in the primary astrocytic glutamate transporter, GLT-1, following infection with Toxoplasma. Using microdialysis of the murine frontal cortex over the course of infection, a significant increase in extracellular concentrations of glutamate is observed. Consistent with glutamate dysregulation, analysis of neurons reveal changes in morphology including a reduction in dendritic spines, VGlut1 and NeuN immunoreactivity. Furthermore, behavioral testing and EEG recordings point to significant changes in neuronal output. Finally, these changes in neuronal connectivity are dependent on infection-induced downregulation of GLT-1 as treatment with the ß-lactam antibiotic ceftriaxone, rescues extracellular glutamate concentrations, neuronal pathology and function. Altogether, these data demonstrate that following an infection with T. gondii, the delicate regulation of glutamate by astrocytes is disrupted and accounts for a range of deficits observed in chronic infection. The protozoan parasite Toxoplasma gondii infects a third of the world’s population and causes a chronic lifelong infection in the brain of the host. The consequences of such an infection are poorly understood. Here, we demonstrate that Toxoplasma infection can induce profound changes in astrocyte physiology leading to significant disruption of neuronal networks. Pathology can be rescued by upregulating the astrocytic glutamate transporter, GLT-1, restoring concentrations of extracellular glutamate and EEG power. We suggest that such global dysregulation of neurotransmitters should be considered when determining the effects of infection on the CNS.
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Affiliation(s)
- Clément N. David
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, California, United States of America
| | - Elma S. Frias
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, California, United States of America
| | - Jenny I. Szu
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, California, United States of America
| | - Philip A. Vieira
- Department of Psychology, University of California, Riverside, Riverside, California, United States of America
| | - Jacqueline A. Hubbard
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, California, United States of America
| | - Jonathan Lovelace
- Department of Psychology, University of California, Riverside, Riverside, California, United States of America
| | - Marena Michael
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, California, United States of America
| | - Danielle Worth
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, California, United States of America
| | - Kathryn E. McGovern
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, California, United States of America
| | - Iryna M. Ethell
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, California, United States of America
| | - B. Glenn Stanley
- Department of Psychology, University of California, Riverside, Riverside, California, United States of America
| | - Edward Korzus
- Department of Psychology, University of California, Riverside, Riverside, California, United States of America
| | - Todd A. Fiacco
- Department of Neuroscience, University of California, Riverside, Riverside, California, United States of America
| | - Devin K. Binder
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, California, United States of America
| | - Emma H. Wilson
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, California, United States of America
- * E-mail:
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