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Huang L, Xiao W, Wang Y, Li J, Gong J, Tu E, Long L, Xiao B, Yan X, Wan L. Metabotropic glutamate receptors (mGluRs) in epileptogenesis: an update on abnormal mGluRs signaling and its therapeutic implications. Neural Regen Res 2024; 19:360-368. [PMID: 37488891 PMCID: PMC10503602 DOI: 10.4103/1673-5374.379018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Revised: 04/07/2023] [Accepted: 05/22/2023] [Indexed: 07/26/2023] Open
Abstract
Epilepsy is a neurological disorder characterized by high morbidity, high recurrence, and drug resistance. Enhanced signaling through the excitatory neurotransmitter glutamate is intricately associated with epilepsy. Metabotropic glutamate receptors (mGluRs) are G protein-coupled receptors activated by glutamate and are key regulators of neuronal and synaptic plasticity. Dysregulated mGluR signaling has been associated with various neurological disorders, and numerous studies have shown a close relationship between mGluRs expression/activity and the development of epilepsy. In this review, we first introduce the three groups of mGluRs and their associated signaling pathways. Then, we detail how these receptors influence epilepsy by describing the signaling cascades triggered by their activation and their neuroprotective or detrimental roles in epileptogenesis. In addition, strategies for pharmacological manipulation of these receptors during the treatment of epilepsy in experimental studies is also summarized. We hope that this review will provide a foundation for future studies on the development of mGluR-targeted antiepileptic drugs.
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Affiliation(s)
- Leyi Huang
- Department of Anatomy and Neurobiology, Central South University Xiangya Medical School, Changsha, Hunan Province, China
| | - Wenjie Xiao
- Department of Anatomy and Neurobiology, Central South University Xiangya Medical School, Changsha, Hunan Province, China
| | - Yan Wang
- Department of Anatomy and Neurobiology, Central South University Xiangya Medical School, Changsha, Hunan Province, China
| | - Juan Li
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan Province, China
| | - Jiaoe Gong
- Department of Neurology, Hunan Children’s Hospital, Changsha, Hunan Province, China
| | - Ewen Tu
- Department of Neurology, Brain Hospital of Hunan Province, Changsha, Hunan Province, China
| | - Lili Long
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan Province, China
| | - Bo Xiao
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan Province, China
| | - Xiaoxin Yan
- Department of Anatomy and Neurobiology, Central South University Xiangya Medical School, Changsha, Hunan Province, China
| | - Lily Wan
- Department of Anatomy and Neurobiology, Central South University Xiangya Medical School, Changsha, Hunan Province, China
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Miao Y, Zhao GL, Cheng S, Wang Z, Yang XL. Activation of retinal glial cells contributes to the degeneration of ganglion cells in experimental glaucoma. Prog Retin Eye Res 2023; 93:101169. [PMID: 36736070 DOI: 10.1016/j.preteyeres.2023.101169] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Revised: 01/12/2023] [Accepted: 01/24/2023] [Indexed: 02/04/2023]
Abstract
Elevation of intraocular pressure (IOP) is a major risk factor for neurodegeneration in glaucoma. Glial cells, which play an important role in normal functioning of retinal neurons, are well involved into retinal ganglion cell (RGC) degeneration in experimental glaucoma animal models generated by elevated IOP. In response to elevated IOP, mGluR I is first activated and Kir4.1 channels are subsequently inhibited, which leads to the activation of Müller cells. Müller cell activation is followed by a complex process, including proliferation, release of inflammatory and growth factors (gliosis). Gliosis is further regulated by several factors. Activated Müller cells contribute to RGC degeneration through generating glutamate receptor-mediated excitotoxicity, releasing cytotoxic factors and inducing microglia activation. Elevated IOP activates microglia, and following morphological and functional changes, these cells, as resident immune cells in the retina, show adaptive immune responses, including an enhanced release of pro-inflammatory factors (tumor neurosis factor-α, interleukins, etc.). These ATP and Toll-like receptor-mediated responses are further regulated by heat shock proteins, CD200R, chemokine receptors, and metabotropic purinergic receptors, may aggravate RGC loss. In the optic nerve head, astrogliosis is initiated and regulated by a complex reaction process, including purines, transmitters, chemokines, growth factors and cytokines, which contributes to RGC axon injury through releasing pro-inflammatory factors and changing extracellular matrix in glaucoma. The effects of activated glial cells on RGCs are further modified by the interplay among different types of glial cells. This review is concluded by presenting an in-depth discussion of possible research directions in this field in the future.
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Affiliation(s)
- Yanying Miao
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, 200032, China
| | - Guo-Li Zhao
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, 200032, China
| | - Shuo Cheng
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, 200032, China
| | - Zhongfeng Wang
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, 200032, China.
| | - Xiong-Li Yang
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, 200032, China.
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Lai YF, Lin TY, Ho PK, Chen YH, Huang YC, Lu DW. Erythropoietin in Optic Neuropathies: Current Future Strategies for Optic Nerve Protection and Repair. Int J Mol Sci 2022; 23:ijms23137143. [PMID: 35806148 PMCID: PMC9267007 DOI: 10.3390/ijms23137143] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 06/13/2022] [Accepted: 06/24/2022] [Indexed: 02/05/2023] Open
Abstract
Erythropoietin (EPO) is known as a hormone for erythropoiesis in response to anemia and hypoxia. However, the effect of EPO is not only limited to hematopoietic tissue. Several studies have highlighted the neuroprotective function of EPO in extra-hematopoietic tissues, especially the retina. EPO could interact with its heterodimer receptor (EPOR/βcR) to exert its anti-apoptosis, anti-inflammation and anti-oxidation effects in preventing retinal ganglion cells death through different intracellular signaling pathways. In this review, we summarized the available pre-clinical studies of EPO in treating glaucomatous optic neuropathy, optic neuritis, non-arteritic anterior ischemic optic neuropathy and traumatic optic neuropathy. In addition, we explore the future strategies of EPO for optic nerve protection and repair, including advances in EPO derivates, and EPO deliveries. These strategies will lead to a new chapter in the treatment of optic neuropathy.
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Affiliation(s)
- Yi-Fen Lai
- Department of Ophthalmology, Tri-Service General Hospital, National Defense Medical Center, Taipei 11490, Taiwan; (Y.-F.L.); (T.-Y.L.); (Y.-H.C.)
| | - Ting-Yi Lin
- Department of Ophthalmology, Tri-Service General Hospital, National Defense Medical Center, Taipei 11490, Taiwan; (Y.-F.L.); (T.-Y.L.); (Y.-H.C.)
| | - Pin-Kuan Ho
- School of Dentistry, National Defense Medical Center, Taipei 11490, Taiwan;
| | - Yi-Hao Chen
- Department of Ophthalmology, Tri-Service General Hospital, National Defense Medical Center, Taipei 11490, Taiwan; (Y.-F.L.); (T.-Y.L.); (Y.-H.C.)
| | - Yu-Chuan Huang
- School of Pharmacy, National Defense Medical Center, Taipei 11490, Taiwan
- Department of Research and Development, National Defense Medical Center, Taipei 11490, Taiwan
- Correspondence: (Y.-C.H.); (D.-W.L.); Tel.: +886-2-87923100 (Y.-C.H.); +886-2-87927163 (D.-W.L.)
| | - Da-Wen Lu
- Department of Ophthalmology, Tri-Service General Hospital, National Defense Medical Center, Taipei 11490, Taiwan; (Y.-F.L.); (T.-Y.L.); (Y.-H.C.)
- Correspondence: (Y.-C.H.); (D.-W.L.); Tel.: +886-2-87923100 (Y.-C.H.); +886-2-87927163 (D.-W.L.)
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Wu X, Dou YN, Fei Z, Fei F. Parkin Prevents Glutamate Excitotoxicity Through Inhibiting NLRP3 Inflammasome in Retinal Ganglion Cells. Neuroscience 2021; 478:1-10. [PMID: 34600073 DOI: 10.1016/j.neuroscience.2021.09.018] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Revised: 09/18/2021] [Accepted: 09/22/2021] [Indexed: 12/26/2022]
Abstract
Glutamate excitotoxicity is one of the important pathophysiological culprits in retinal ganglion cells (RGCs) damage after acute optic nerve injury such as traumatic optic neuropathies and glaucoma. It is necessary to elucidate the mechanism of glutamate injury to RGCs in order to find the relevant neuroprotector. In this study, it was observed that the expression of Parkin increased and peaked at 24 h after glutamate injury to RGCs. Moreover, upregulating Parkin attenuated glutamate induced apoptosis, mitochondrial dysfunction and oxidative stress. And, it was found that Parkin could exert neuroprotective effects on RGCs by inhibiting nucleotide-binding domain leucine-rich repeat containing family pyrin domain containing 3 (NLRP3) inflammasome. Moreover, the genetic and pharmacological downregulation of NLRP3 improved survival of RGCs against glutamate excitotoxicity. In the end, knockdown of Parkin exacerbated glutamate induced RGCs damage via triggering NLRP3 inflammasome activation. Taken together, these results shed light on the promising molecular targets for the prevention and treatment of acute optic nerve injury.
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Affiliation(s)
- Xiuquan Wu
- Department of Neurosurgery, Xijing Hospital, the Fourth Military Medical University, 15 Changle West Road, Xi'an 71032, People's Republic of China
| | - Ya-Nan Dou
- Department of Neurosurgery, Xijing Hospital, the Fourth Military Medical University, 15 Changle West Road, Xi'an 71032, People's Republic of China
| | - Zhou Fei
- Department of Neurosurgery, Xijing Hospital, the Fourth Military Medical University, 15 Changle West Road, Xi'an 71032, People's Republic of China.
| | - Fei Fei
- Department of Ophthalmology, Xijing Hospital, the Fourth Military Medical University, 15 Changle West Road, Xi'an 71032, People's Republic of China.
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Li Q, Cheng Y, Zhang S, Sun X, Wu J. TRPV4-induced Müller cell gliosis and TNF-α elevation-mediated retinal ganglion cell apoptosis in glaucomatous rats via JAK2/STAT3/NF-κB pathway. J Neuroinflammation 2021; 18:271. [PMID: 34789280 PMCID: PMC8596927 DOI: 10.1186/s12974-021-02315-8] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Accepted: 11/01/2021] [Indexed: 01/22/2023] Open
Abstract
Background Glaucoma, the leading cause of irreversible blindness worldwide, is a type of retinal disease characterized by the selective death of retinal ganglion cells (RGCs). However, the pathogenesis of glaucoma has not been fully elucidated. Transient receptor potential vanilloid 4 (TRPV4) is a pressure-sensitive and calcium-permeable cation channel. TRPV4 is widely distributed in the retina and its sustained activation leads to RGC death; indicating that TRPV4 may be a possible target for glaucoma treatment. Here, we investigated the effects of TRPV4 on RGC apoptosis in a rat model of chronic ocular hypertension (COH), then examined the mechanism underlying these effects. Methods The COH model was established by injection of micro-magnetic beads into the anterior chamber of adult male rats. The expression levels of TRPV4, glial fibrillary acidic protein, and inflammatory factors were assessed by immunohistochemistry and immunoblotting. RGC apoptosis and visual dysfunction were evaluated by TUNEL assay and photopic negative response. Functional expression of TRPV4 was examined by electrophysiology and calcium imaging. Real-time polymerase chain reaction and immunoblotting were employed to investigate the molecular mechanism underlying the effects of TRPV4 on tumor necrosis factor-α (TNF-α) release. Results We found that TRPV4 played an essential role in glaucoma, such that high levels of TRPV4 expression were associated with elevated intraocular pressure. Furthermore, TRPV4 activation was involved in glaucoma-induced RGC apoptosis and RGC-related reductions in visual function. Mechanistic investigation demonstrated that TRPV4 activation led to enhanced Müller cell gliosis and TNF-α release via the JAK2/STAT3/NF-kB pathway, while TRPV4 inhibition could reverse these effects. Finally, TRPV4 activation could lead to elevated expression of TNF receptor 1 in RGCs, while inhibition of TNF-α could reduce TRPV4-mediated RGC apoptosis. Conclusions TRPV4 activation induces Müller cell gliosis and TNF-α elevation via the JAK2/STAT3/NF-κB pathway, which may exacerbate RGC apoptosis in glaucoma; these results suggest that TRPV4 can serve as a therapeutic target in glaucoma treatment. Supplementary Information The online version contains supplementary material available at 10.1186/s12974-021-02315-8.
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Affiliation(s)
- Qian Li
- Eye Institute, Eye and ENT Hospital, College of Medicine, Fudan University, Shanghai, China.,Shanghai Key Laboratory of Visual Impairment and Restoration, Science and Technology Commission of Shanghai Municipality, Shanghai, China.,NHC Key Laboratory of Myopia, Fudan University, Shanghai, China.,Key Laboratory of Myopia, Chinese Academy of Medical Sciences, National Health Commission, #83 Fenyang Road, 200031, Shanghai, China
| | - Yun Cheng
- Eye Institute, Eye and ENT Hospital, College of Medicine, Fudan University, Shanghai, China.,Shanghai Key Laboratory of Visual Impairment and Restoration, Science and Technology Commission of Shanghai Municipality, Shanghai, China.,NHC Key Laboratory of Myopia, Fudan University, Shanghai, China.,Key Laboratory of Myopia, Chinese Academy of Medical Sciences, National Health Commission, #83 Fenyang Road, 200031, Shanghai, China
| | - Shenghai Zhang
- Shanghai Key Laboratory of Visual Impairment and Restoration, Science and Technology Commission of Shanghai Municipality, Shanghai, China.,NHC Key Laboratory of Myopia, Fudan University, Shanghai, China.,Key Laboratory of Myopia, Chinese Academy of Medical Sciences, National Health Commission, #83 Fenyang Road, 200031, Shanghai, China
| | - Xinghuai Sun
- Eye Institute, Eye and ENT Hospital, College of Medicine, Fudan University, Shanghai, China. .,Shanghai Key Laboratory of Visual Impairment and Restoration, Science and Technology Commission of Shanghai Municipality, Shanghai, China. .,NHC Key Laboratory of Myopia, Fudan University, Shanghai, China. .,Key Laboratory of Myopia, Chinese Academy of Medical Sciences, National Health Commission, #83 Fenyang Road, 200031, Shanghai, China.
| | - Jihong Wu
- Eye Institute, Eye and ENT Hospital, College of Medicine, Fudan University, Shanghai, China. .,Shanghai Key Laboratory of Visual Impairment and Restoration, Science and Technology Commission of Shanghai Municipality, Shanghai, China. .,NHC Key Laboratory of Myopia, Fudan University, Shanghai, China. .,Key Laboratory of Myopia, Chinese Academy of Medical Sciences, National Health Commission, #83 Fenyang Road, 200031, Shanghai, China.
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Li Q, Jin R, Zhang S, Sun X, Wu J. Transient receptor potential vanilloid four channels modulate inhibitory inputs through differential regulation of GABA and glycine receptors in rat retinal ganglion cells. FASEB J 2020; 34:14521-14538. [PMID: 32892440 DOI: 10.1096/fj.201902937rr] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Revised: 08/07/2020] [Accepted: 08/18/2020] [Indexed: 01/06/2023]
Abstract
The transient receptor potential vanilloid 4 (TRPV4) channel is widely distributed in the retina. Activation of the TRPV4 channel enhances excitatory signaling from bipolar cells to retinal ganglion cells (RGCs), thereby increasing RGC firing rate and membrane excitability. In this study, we investigated the effect of TRPV4 channel activation on the miniature inhibitory postsynaptic current (mIPSC) in rat RGCs. Our results showed that perfusion with HC-067047, a TRPV4-channel antagonist, significantly reduced the amplitude of RGC mIPSCs. Extracellular application of the TRPV4 channel agonist GSK1016790A (GSK101) enhanced the frequency and amplitude of mIPSCs in ON- and OFF-type RGCs; pre-application of HC-067047 blocked the effect of GSK101 on mIPSCs. Furthermore, TRPV4 channels were able to enhance the frequency and amplitude of glycine receptor (GlyR)-mediated mIPSCs and inhibit the frequency of type A γ-aminobutyric acid receptor (GABAA R)-mediated mIPSCs. Upon intracellular administration or intravitreal injection of GSK101, TRPV4 channel activation reduced the release of presynaptic glycine and enhanced the function and expression of postsynaptic GlyRs; however, it inhibited presynaptic release of GABA, but did not affect postsynaptic GABAA Rs. Our study results provide insight regarding the effect of TRPV4 channel activation on RGCs and offer a potential interventional target for retinal diseases involving TRPV4 channels.
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Affiliation(s)
- Qian Li
- Eye Institute, Eye and ENT Hospital, Fudan University, Shanghai, China.,Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai, China.,NHC Key Laboratory of Myopia (Fudan University), Shanghai, China.,Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China
| | - Ruiri Jin
- Department of Gastroenterology, The First Affiliated Hospital of Nanchang University, Nanchang, China
| | - Shenghai Zhang
- Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai, China.,NHC Key Laboratory of Myopia (Fudan University), Shanghai, China.,Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China
| | - Xinghuai Sun
- Eye Institute, Eye and ENT Hospital, Fudan University, Shanghai, China.,Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai, China.,NHC Key Laboratory of Myopia (Fudan University), Shanghai, China.,Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China
| | - Jihong Wu
- Eye Institute, Eye and ENT Hospital, Fudan University, Shanghai, China.,Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai, China.,NHC Key Laboratory of Myopia (Fudan University), Shanghai, China.,Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China
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