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Albini M, Krawczun-Rygmaczewska A, Cesca F. Astrocytes and brain-derived neurotrophic factor (BDNF). Neurosci Res 2023; 197:42-51. [PMID: 36780947 DOI: 10.1016/j.neures.2023.02.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Revised: 01/17/2023] [Accepted: 02/02/2023] [Indexed: 02/13/2023]
Abstract
Astrocytes are emerging in the neuroscience field as crucial modulators of brain functions, from the molecular control of synaptic plasticity to orchestrating brain-wide circuit activity for cognitive processes. The cellular pathways through which astrocytes modulate neuronal activity and plasticity are quite diverse. In this review, we focus on neurotrophic pathways, mostly those mediated by brain-derived neurotrophic factor (BDNF). Neurotrophins are a well-known family of trophic factors with pleiotropic functions in neuronal survival, maturation and activity. Within the brain, BDNF is the most abundantly expressed and most studied of all neurotrophins. While we have detailed knowledge of the effect of BDNF on neurons, much less is known about its physiology on astroglia. However, over the last years new findings emerged demonstrating that astrocytes take an active part into BDNF physiology. In this work, we discuss the state-of-the-art knowledge about astrocytes and BDNF. Indeed, astrocytes sense extracellular BDNF through its specific TrkB receptors and activate intracellular responses that greatly vary depending on the brain area, stage of development and receptors expressed. Astrocytes also uptake and recycle BDNF / proBDNF at synapses contributing to synaptic plasticity. Finally, experimental evidence is now available describing deficits in astrocytic BDNF in several neuropathologies, suggesting that astrocytic BDNF may represent a promising target for clinical translation.
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Affiliation(s)
- Martina Albini
- Department of Experimental Medicine, University of Genova, Italy; IIT Center for Synaptic Neuroscience and Technology, Genova, Italy
| | - Alicja Krawczun-Rygmaczewska
- IIT Center for Synaptic Neuroscience and Technology, Genova, Italy; Department of Life Sciences, University of Trieste, Italy
| | - Fabrizia Cesca
- IIT Center for Synaptic Neuroscience and Technology, Genova, Italy; Department of Life Sciences, University of Trieste, Italy.
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Fafure AA, Edem EE, Obisesan AO, Enye LA, Adekeye AO, Adetunji AE, Nebo KE, Olusegun AA, Fafure OE. Fermented maize slurry (Ogi) and its supernatant (Omidun) mitigate elevated intraocular pressure by modulating BDNF expression and glial plasticity in the retina-gut axis of glaucomatous rats. JOURNAL OF COMPLEMENTARY & INTEGRATIVE MEDICINE 2022; 19:887-896. [PMID: 34380184 DOI: 10.1515/jcim-2021-0114] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2021] [Accepted: 07/27/2021] [Indexed: 06/13/2023]
Abstract
OBJECTIVES Growing interest has been reported on the health benefits of fermented foods, which includes cognition enhancement and inflammation attenuation. BDNF is a known protectant against retinal degeneration, however, therapies that target this neurotrophic factor has been limited. Therefore, we assessed the reaction of BDNF and glial cells in glaucomatous rats and their response to treatment with fermented maize products. METHODS Thirty male adult rats were either injected via the episcleral vein with hypertonic saline to elevate intraocular pressure (IOP) or treated with fermented maize slurry (Ogi) or its supernatant (Omidun). Following sacrifice, the retina and duodenum were studied by immunohistochemical analysis using antibodies directed against GFAP, AIF-1 and BDNF. RESULTS Hypertonic saline injection produced hypertrophy of the Müller cells and increased GFAP and AIF-1 expression in the retina and gut when compared to the control. Treatment with Ogi and Omidun produced varying degrees of reduction of gliosis, protection against hypertonic saline-induced retinal ganglion cell loss, and reduced intraocular pressure. BDNF expression was downregulated following the hypertonic saline assault, while Omidun and Ogi treatment abrogated its reduction following the hypertonic saline assault. CONCLUSIONS Collectively, our findings suggest that acute elevation of IOP alters crosstalk between gut and retina with consequent aberrant activation of glial cells; and that probiotic bacteria like the lactic acid bacteria rich in fermented foods including Ogi and Omidun may offer neuroprotection to the ganglionic cells by attenuating the retinal glial reaction and improving BDNF activity.
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Affiliation(s)
- Adedamola Adediran Fafure
- Neuroscience Unit, Department of Anatomy, Faculty of Basic Medical Sciences, College of Medicine and Health Sciences, Afe Babalola University, Ado-Ekiti, Nigeria
| | - Edem Ekpenyong Edem
- Neuroscience Unit, Department of Anatomy, Faculty of Basic Medical Sciences, College of Medicine and Health Sciences, Afe Babalola University, Ado-Ekiti, Nigeria
| | - Abiola Oluwatosin Obisesan
- Department of Pharmaceutical Microbiology, Faculty of Pharmacy, College of Medicine and Health Sciences, Afe Babalola University, Ado-Ekiti, Nigeria
| | - Linus Anderson Enye
- Neuroscience Unit, Department of Anatomy, Faculty of Basic Medical Sciences, College of Medicine and Health Sciences, Afe Babalola University, Ado-Ekiti, Nigeria
| | - Adeshina Oloruntoba Adekeye
- Neuroscience Unit, Department of Anatomy, Faculty of Basic Medical Sciences, College of Medicine and Health Sciences, Afe Babalola University, Ado-Ekiti, Nigeria
| | - Adedeji Enitan Adetunji
- Neuroscience Unit, Department of Anatomy, Faculty of Basic Medical Sciences, College of Medicine and Health Sciences, Afe Babalola University, Ado-Ekiti, Nigeria
| | - Kate Eberechukwu Nebo
- Neuroscience Unit, Department of Anatomy, Faculty of Basic Medical Sciences, College of Medicine and Health Sciences, Afe Babalola University, Ado-Ekiti, Nigeria
| | - Adebayo Adeoluwa Olusegun
- Neuropharmacology Unit, Department of Pharmacology and Therapeutics, College of Medicine and Health Sciences, Afe-Babalola University, Ado-Ekiti, Nigeria
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Lee K, Choi JO, Hwang A, Bae HW, Kim CY. Ciliary Neurotrophic Factor Derived From Astrocytes Protects Retinal Ganglion Cells Through PI3K/AKT, JAK/STAT, and MAPK/ERK Pathways. Invest Ophthalmol Vis Sci 2022; 63:4. [PMID: 35925584 PMCID: PMC9363680 DOI: 10.1167/iovs.63.9.4] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose The purpose of this study was to investigate the roles of ciliary neurotrophic factor (CNTF) on the protective effects of astrocytes on retinal ganglion cells (RGCs). Methods Primary RGCs were isolated from neonatal rats. Oxidative stress was induced, and the effects of co-culture with astrocytes and CNTF treatment on RGCs were evaluated. The pathways commonly altered by astrocytes and CNTF were investigated. Effects of each pathway were investigated using pathway inhibitors against PI3K/AKT, JAK/STAT, and MAPK/ERK. RNA sequencing was performed to identify the genes upregulated and downregulated by CNTF treatment. Results Astrocytes improved the viability and increased β3-tubulin expression in RGCs. The concentration of CNTF increased in the RGC-astrocyte co-culture medium. The protective effects of astrocytes were abolished by neutralization with the anti-CNTF antibody; thus, CNTF may play an important role in the effects mediated by astrocytes. Furthermore, CNTF treatment alone enhanced the viability and β3-tubulin expression of RGCs and increased the population of viable RGCs under oxidative stress. The PI3K/AKT pathway was associated with both RGC viability and β3-tubulin expression. However, the JAK/STAT pathway increased the viability of RGCs, whereas the MAPK/ERK pathway was associated with β3-tubulin expression. RNA sequencing revealed the CNTF-upregulated genes associated with response to DNA damage and downregulated genes associated with photoreceptor cell differentiation. Conclusions Our data revealed protective effects of astrocyte-derived CNTF on RGCs. In addition, we showed that multiple pathways exert these protective effects and identified the novel genes involved. These results may be helpful in developing treatments for RGC injury.
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Affiliation(s)
- Kwanghyun Lee
- Institute of Vision Research, Department of Ophthalmology, Yonsei University College of Medicine, Seoul, Republic of Korea.,Department of Ophthalmology, National Health Insurance Service Ilsan Hospital, Goyang, Gyeonggi-do, Republic of Korea
| | - Jin-Ok Choi
- Institute of Vision Research, Department of Ophthalmology, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Ahreum Hwang
- Institute of Vision Research, Department of Ophthalmology, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Hyoung Won Bae
- Institute of Vision Research, Department of Ophthalmology, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Chan Yun Kim
- Institute of Vision Research, Department of Ophthalmology, Yonsei University College of Medicine, Seoul, Republic of Korea
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Lambuk L, Mohd Lazaldin MA, Ahmad S, Iezhitsa I, Agarwal R, Uskoković V, Mohamud R. Brain-Derived Neurotrophic Factor-Mediated Neuroprotection in Glaucoma: A Review of Current State of the Art. Front Pharmacol 2022; 13:875662. [PMID: 35668928 PMCID: PMC9163364 DOI: 10.3389/fphar.2022.875662] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Accepted: 04/28/2022] [Indexed: 12/14/2022] Open
Abstract
Retinal ganglion cells (RGCs) are neurons of the visual system that are responsible for transmitting signals from the retina to the brain via the optic nerve. Glaucoma is an optic neuropathy characterized by apoptotic loss of RGCs and degeneration of optic nerve fibers. Risk factors such as elevated intraocular pressure and vascular dysregulation trigger the injury that culminates in RGC apoptosis. In the event of injury, the survival of RGCs is facilitated by neurotrophic factors (NTFs), the most widely studied of which is brain-derived neurotrophic factor (BDNF). Its production is regulated locally in the retina, but transport of BDNF retrogradely from the brain to retina is also crucial. Not only that the interruption of this retrograde transport has been detected in the early stages of glaucoma, but significantly low levels of BDNF have also been detected in the sera and ocular fluids of glaucoma patients, supporting the notion that neurotrophic deprivation is a likely mechanism of glaucomatous optic neuropathy. Moreover, exogenous NTF including BDNF administration was shown reduce neuronal loss in animal models of various neurodegenerative diseases, indicating the possibility that exogenous BDNF may be a treatment option in glaucoma. Current literature provides an extensive insight not only into the sources, transport, and target sites of BDNF but also the intracellular signaling pathways, other pathways that influence BDNF signaling and a wide range of its functions. In this review, the authors discuss the neuroprotective role of BDNF in promoting the survival of RGCs and its possible application as a therapeutic tool to meet the challenges in glaucoma management. We also highlight the possibility of using BDNF as a biomarker in neurodegenerative disease such as glaucoma. Further we discuss the challenges and future strategies to explore the utility of BDNF in the management of glaucoma.
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Affiliation(s)
- Lidawani Lambuk
- Department of Immunology, School of Medical Sciences, Universiti Sains Malaysia, Kota Bharu, Malaysia
| | | | - Suhana Ahmad
- Department of Immunology, School of Medical Sciences, Universiti Sains Malaysia, Kota Bharu, Malaysia
| | - Igor Iezhitsa
- Department of Pharmacology and Therapeutics, School of Medicine, International Medical University, Kuala Lumpur, Malaysia
- Department of Pharmacology and Bioinformatics, Volgograd State Medical University, Volgograd, Russia
| | - Renu Agarwal
- Department of Pharmacology and Therapeutics, School of Medicine, International Medical University, Kuala Lumpur, Malaysia
| | - Vuk Uskoković
- TardigradeNano LLC, Irvine, CA, United States
- Department of Mechanical Engineering, San Diego State University, San Diego, CA, United States
| | - Rohimah Mohamud
- Department of Immunology, School of Medical Sciences, Universiti Sains Malaysia, Kota Bharu, Malaysia
- *Correspondence: Rohimah Mohamud,
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Harnessing Astrocytes and Müller Glial Cells in the Retina for Survival and Regeneration of Retinal Ganglion Cells. Cells 2021; 10:cells10061339. [PMID: 34071545 PMCID: PMC8229010 DOI: 10.3390/cells10061339] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Revised: 05/24/2021] [Accepted: 05/26/2021] [Indexed: 01/17/2023] Open
Abstract
Astrocytes have been associated with the failure of axon regeneration in the central nervous system (CNS), as it undergoes reactive gliosis in response to damages to the CNS and functions as a chemical and physical barrier to axon regeneration. However, beneficial roles of astrocytes have been extensively studied in the spinal cord over the years, and a growing body of evidence now suggests that inducing astrocytes to become more growth-supportive can promote axon regeneration after spinal cord injury (SCI). In retina, astrocytes and Müller cells are known to undergo reactive gliosis after damage to retina and/or optic nerve and are hypothesized to be either detrimental or beneficial to survival and axon regeneration of retinal ganglion cells (RGCs). Whether they can be induced to become more growth-supportive after retinal and optic nerve injury has yet to be determined. In this review, we pinpoint the potential molecular pathways involved in the induction of growth-supportive astrocytes in the spinal cord and suggest that stimulating the activation of these pathways in the retina could represent a new therapeutic approach to promoting survival and axon regeneration of RGCs in retinal degenerative diseases.
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Huang HM, Huang CC, Poon LYC, Chang YC. Artemin Is Upregulated by TrkB Agonist and Protects the Immature Retina Against Hypoxic-Ischemic Injury by Suppressing Neuroinflammation and Astrogliosis. Front Mol Neurosci 2021; 14:645000. [PMID: 33912011 PMCID: PMC8072488 DOI: 10.3389/fnmol.2021.645000] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Accepted: 03/17/2021] [Indexed: 11/22/2022] Open
Abstract
Hypoxic-ischemia (HI) is a major cause of acquired visual impairment in children from developed countries. Previous studies have shown that systemic administration of 7,8-dihydroxyavone (DHF), a selective tropomyosin receptor kinase B (TrkB) agonist, provides long-term neuroprotection against HI injury in an immature retina. However, the target genes and the mechanisms of the neuroprotective effects of TrkB signaling are not known. In the present study, we induced an HI retinal injury through unilateral common carotid artery ligation followed by 8% oxygen for 2 h in P7 rat pups. DHF was administered intraperitoneally 2 h before and 18 h after the HI injury. A polymerase chain reaction (PCR) array was used to identify the target genes upregulated after the DHF treatment, which was then confirmed with quantitative real-time reverse transcriptase PCR and a western blot. Effects of the downstream mediator of DHF were assessed using an intravitreal injection of neutralizing antibody 4 h after DHF administration (24 h after HI). Meanwhile, the target protein was injected into the vitreous 24 h after HI to validate its protective effect when exogenously supplemented. We found that systemic DHF treatment after HI significantly increased the expression of the artemin (ARTN) gene and protein at P8 and P10, respectively. The neuroprotective effects of DHF were inhibited after the ARTN protein blockade, with an increase in neuroinflammation and astrogliosis. ARTN treatment showed long-term protection against HI injury at both the histopathological and functional levels. The neuroprotective effects of ARTN were related to a decrease in microglial activation at P17 and attenuation of astrogliosis at P29. ARTN enhances phosphorylation of RET, ERK, and JNK, but not AKT or p38 in the immature retina. Altogether, these results suggest that the neuroprotective effect of a TrkB agonist is partially exerted through a mechanism that involves ARTN because the protective effect is ameliorated by ARTN sequestration. ARTN treatment after HI injury protects the immature retina by attenuating late neuroinflammation and astrogliosis in the immature retina relating to the ARTN/RET/JNK/ERK signaling pathway. ARTN may be a strategy by which to provide long-term protection in the immature retina against HI injury.
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Affiliation(s)
- Hsiu-Mei Huang
- Department of Ophthalmology, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Kaohsiung City, Taiwan
| | - Chao-Ching Huang
- Department of Pediatrics, National Cheng Kung University Hospital, Tainan, Taiwan
| | - Linda Yi-Chieh Poon
- Department of Ophthalmology, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Kaohsiung City, Taiwan
| | - Ying-Chao Chang
- Department of Pediatrics, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Kaohsiung City, Taiwan
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Khatib TZ, Osborne A, Yang S, Ali Z, Jia W, Manyakin I, Hall K, Watt R, Widdowson PS, Martin KR. Receptor-ligand supplementation via a self-cleaving 2A peptide-based gene therapy promotes CNS axonal transport with functional recovery. SCIENCE ADVANCES 2021; 7:eabd2590. [PMID: 33789891 PMCID: PMC8011959 DOI: 10.1126/sciadv.abd2590] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Accepted: 02/09/2021] [Indexed: 06/12/2023]
Abstract
Gene replacement approaches are leading to a revolution in the treatment of previously debilitating monogenic neurological conditions. However, the application of gene therapy to complex polygenic conditions has been limited. Down-regulation or dysfunction of receptor expression in the disease state or in the presence of excess ligand has been shown to compromise therapeutic efficacy. Here, we offer evidence that combined overexpression of both brain-derived neurotrophic factor and its receptor, tropomyosin receptor kinase B, is more effective in stimulating axonal transport than either receptor administration or ligand administration alone. We also show efficacy in experimental glaucoma and humanized tauopathy models. Simultaneous administration of a ligand and its receptor by a single gene therapy vector overcomes several problems relating to ligand deficiency and receptor down-regulation that may be relevant to multiple neurodegenerative diseases. This approach shows promise as a strategy to target intrinsic mechanisms to improve neuronal function and facilitate repair.
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Affiliation(s)
- Tasneem Z Khatib
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK.
- Eye Department, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK
- Medical Sciences Division, University of Oxford, Oxford, UK
| | - Andrew Osborne
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
- Quethera Ltd., Cambridge, UK
- Ikarovec Ltd., Norwich Innovation Centre, Norwich, UK
| | - Sujeong Yang
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Zara Ali
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
- School of Clinical Medicine, University of Cambridge, Cambridge, UK
| | - Wanyi Jia
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Ilya Manyakin
- Department of Physics, University of Cambridge, Cambridge, UK
| | - Katie Hall
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Robert Watt
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Peter S Widdowson
- Quethera Ltd., Cambridge, UK
- Ikarovec Ltd., Norwich Innovation Centre, Norwich, UK
| | - Keith R Martin
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK.
- Eye Department, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK
- Quethera Ltd., Cambridge, UK
- Cambridge NIHR Biomedical Research Centre, Cambridge, UK
- Wellcome Trust-MRC Cambridge Stem Cell Institute, University of Cambridge, Cambridge, UK
- Ophthalmology, Department of Surgery, University of Melbourne, Melbourne, Australia
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Australia
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Namekata K, Guo X, Kimura A, Arai N, Harada C, Harada T. DOCK8 is expressed in microglia, and it regulates microglial activity during neurodegeneration in murine disease models. J Biol Chem 2019; 294:13421-13433. [PMID: 31337702 DOI: 10.1074/jbc.ra119.007645] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Revised: 06/25/2019] [Indexed: 12/15/2022] Open
Abstract
Dedicator of cytokinesis 8 (DOCK8) is a guanine nucleotide exchange factor whose loss of function results in immunodeficiency, but its role in the central nervous system (CNS) has been unclear. Microglia are the resident immune cells of the CNS and are implicated in the pathogenesis of various neurodegenerative diseases, including multiple sclerosis (MS) and glaucoma, which affects the visual system. However, the exact roles of microglia in these diseases remain unknown. Herein, we report that DOCK8 is expressed in microglia but not in neurons or astrocytes and that its expression is increased during neuroinflammation. To define the role of DOCK8 in microglial activity, we focused on the retina, a tissue devoid of infiltrating T cells. The retina is divided into distinct layers, and in a disease model of MS/optic neuritis, DOCK8-deficient mice exhibited a clear reduction in microglial migration through these layers. Moreover, neuroinflammation severity, indicated by clinical scores, visual function, and retinal ganglion cell (RGC) death, was reduced in the DOCK8-deficient mice. Furthermore, using a glaucoma disease model, we observed impaired microglial phagocytosis of RGCs in DOCK8-deficient mice. Our data demonstrate that DOCK8 is expressed in microglia and regulates microglial activity in disease states. These findings contribute to a better understanding of the molecular pathways involved in microglial activation and implicate a role of DOCK8 in several neurological diseases.
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Affiliation(s)
- Kazuhiko Namekata
- Visual Research Project, Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506, Japan
| | - Xiaoli Guo
- Visual Research Project, Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506, Japan
| | - Atsuko Kimura
- Visual Research Project, Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506, Japan
| | - Nobutaka Arai
- Brain Pathology Research Center, Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506, Japan
| | - Chikako Harada
- Visual Research Project, Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506, Japan
| | - Takayuki Harada
- Visual Research Project, Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506, Japan.
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Telegina DV, Kolosova NG, Kozhevnikova OS. Immunohistochemical localization of NGF, BDNF, and their receptors in a normal and AMD-like rat retina. BMC Med Genomics 2019; 12:48. [PMID: 30871541 PMCID: PMC6417162 DOI: 10.1186/s12920-019-0493-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Age-related macular degeneration (AMD) is a major cause of blindness in developed countries, and the molecular pathogenesis of AMD is poorly understood. A large body of evidence has corroborated the key role of neurotrophins in development, proliferation, differentiation, and survival of retinal cells. Neurotrophin deprivation has been proposed to contribute to retinal-cell death associated with neurodegenerative diseases. Little is known about the expression of the immature form of neurotrophins (proneurotrophins) and their mature form [e.g., nerve growth factor (proNGF and mNGF) and brain-derived neurotrophic factor (proBDNF and mBDNF)] in the retina during physiological aging and against the background of AMD. In addition, cell-specific localization of proteins NGF and BDNF in the retina during AMD development is not clear. Here, we evaluated contributions of the age-related alterations in the neurotrophin system to the development of AMD-like retinopathy in OXYS rats. METHODS Male OXYS rats at preclinical (20 days), early (3 months), and late (18 months) stages of the disease and age-matched male Wistar rats (as controls) were used. We performed immunohistochemical localization of NGF, BDNF, and their receptors TrkA, TrkB, and p75NTR by fluorescence microscopy in retinal sections from OXYS and Wistar rats. RESULTS We found increased NGF staining in Muller cells in 18-month-old OXYS rats (progressive stage of retinopathy). In contrast, we observed only subtle changes in the labeling of mature BDNF (mBDNF) and TrkB during the development of AMD-like retinopathy in OXYS rats. Using colocalization with vimentin and NeuN, we detected a difference in the cell type-specific localization of mBDNF between OXYS and Wistar rats. We showed that the mBDNF protein was located in Muller cells in OXYS rats, whereas in the Wistar retina, mBDNF immunoreactivity was detected in Muller cells and ganglion cells. During the development of AMD-like retinopathy, proBDNF dominated over mBDNF during increasing cell loss in the OXYS retina. CONCLUSIONS These data indicate that alterations in the balance of neurotrophic factors in the retina are involved in the development of AMD-like retinopathy in OXYS rats and confirm their participation in the pathogenesis of AMD in humans.
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Affiliation(s)
| | - Nataliya G. Kolosova
- Institute of Cytology and Genetics, SB RAS, Novosibirsk, Russia
- N. N. Vorozhtsov Novosibirsk Institute of Organic Chemistry, SB RAS, Novosibirsk, Russia
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10
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Osborne A, Khatib TZ, Songra L, Barber AC, Hall K, Kong GYX, Widdowson PS, Martin KR. Neuroprotection of retinal ganglion cells by a novel gene therapy construct that achieves sustained enhancement of brain-derived neurotrophic factor/tropomyosin-related kinase receptor-B signaling. Cell Death Dis 2018; 9:1007. [PMID: 30258047 PMCID: PMC6158290 DOI: 10.1038/s41419-018-1041-8] [Citation(s) in RCA: 92] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Revised: 09/04/2018] [Accepted: 09/07/2018] [Indexed: 01/17/2023]
Abstract
Previous studies have demonstrated that intravitreal delivery of brain-derived neurotrophic factor (BDNF) by injection of recombinant protein or by gene therapy can alleviate retinal ganglion cell (RGC) loss after optic nerve injury. BDNF gene therapy can improve RGC survival in experimental models of glaucoma, the leading cause of irreversible blindness worldwide. However, the therapeutic efficacy of BDNF supplementation alone is time limited at least in part due to BDNF receptor downregulation. Tropomyosin-related receptor kinase-B (TrkB) downregulation has been reported in many neurological diseases including glaucoma, potentially limiting the effect of sustained or repeated BDNF delivery. Here, we characterize a novel adeno-associated virus (AAV) gene therapy (AAV2 TrkB-2A-mBDNF) that not only increases BDNF production but also improves long-term neuroprotective signaling by increasing expression of the BDNF receptor (TrkB) within the inner retina. This approach leads to significant and sustained elevation of survival signaling pathways ERK and AKT within RGCs over 6 months and avoids the receptor downregulation which we observe with treatment with AAV2 BDNF alone. We validate the neuroprotective efficacy of AAV2 TrkB-2A-mBDNF in a mouse model of optic nerve injury, where it outperforms conventional AAV2 BDNF or AAV2 TrkB therapy, before showing powerful proof of concept neuroprotection of RGCs and axons in a rat model of chronic intraocular pressure (IOP) elevation. We also show that there are no adverse effects of the vector on retinal structure or function as assessed by histology and electroretinography in young or aged animals. Further studies are underway to explore the potential of this vector as a candidate for progression into clinical studies to protect RGCs in patients with glaucoma and progressive visual loss despite conventional IOP-lowering treatment.
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Affiliation(s)
- Andrew Osborne
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK.,Quethera Ltd, Babraham Research Campus, Cambridge, UK
| | - Tasneem Z Khatib
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK.,Eye Department, Addenbrooke's Hospital, Cambridge, UK
| | - Lalana Songra
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Amanda C Barber
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Katie Hall
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - George Y X Kong
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Australia.,University of Melbourne, Melbourne, Australia
| | | | - Keith R Martin
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK. .,Quethera Ltd, Babraham Research Campus, Cambridge, UK. .,Eye Department, Addenbrooke's Hospital, Cambridge, UK. .,Cambridge NIHR Biomedical Research Centre, Cambridge, UK. .,Wellcome Trust-MRC Cambridge Stem Cell Institute, University of Cambridge, Cambridge, UK.
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11
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Role of neuritin in retinal ganglion cell death in adult mice following optic nerve injury. Sci Rep 2018; 8:10132. [PMID: 29973613 PMCID: PMC6031618 DOI: 10.1038/s41598-018-28425-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Accepted: 06/21/2018] [Indexed: 12/31/2022] Open
Abstract
Neuritin is a small extracellular protein that plays important roles in the process of neural development, synaptic plasticity, and neural cell survival. Here we investigated the function of neuritin in a mouse model of optic nerve injury (ONI). ONI induced upregulation of neuritin mRNA in the retina of WT mice. The retinal structure and the number of retinal ganglion cells (RGCs) were normal in adult neuritin knockout (KO) mice. In vivo retinal imaging and histopathological analyses demonstrated that RGC death and inner retinal degeneration following ONI were more severe in neuritin KO mice. Immunoblot analyses revealed that ONI-induced phosphorylation of Akt and ERK were suppressed in neuritin KO mice. Our findings suggest that neuritin has neuroprotective effects following ONI and may be useful for treatment of posttraumatic complication.
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Garcia TB, Hollborn M, Bringmann A. Expression and signaling of NGF in the healthy and injured retina. Cytokine Growth Factor Rev 2017; 34:43-57. [PMID: 27964967 DOI: 10.1016/j.cytogfr.2016.11.005] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Accepted: 11/28/2016] [Indexed: 01/02/2023]
Abstract
This review summarizes the present knowledge concerning the retinal localization of the nerve growth factor (NGF), its precursor proNGF, and the receptors TrkA and p75NTR in the developing and mature rodent retina. We further discuss the changes in the expression of NGF and the receptors in experimental models of retinal disorders and diseases like inherited retinitis pigmentosa, retinal detachment, glaucoma, and diabetic retinopathy. Since proNGF is now recognized as a bioactive signaling molecule which induces cell death through p75NTR activation, the role of proNGF in the induction of retinal cell loss under neurodegenerative conditions is also highlighted. In addition, we present the evidences for a potential therapeutic intervention with NGF for the treatment of retinal neurodegenerative diseases. Different strategies have been developed and experimentally tested in mice and rats in order to reduce cell loss and Müller cell gliosis, e.g., increasing the availability of endogenous NGF, administration of exogenous NGF, activation of TrkA, and inhibition of p75NTR. Here, we discuss the several lines of evidence supporting a protective effect of NGF on retinal cell loss, with specific emphasis on photoreceptor and retinal ganglion cell degeneration. A better understanding of the mechanisms underlying the effects of NGF and proNGF in the modulation of neurodegeneration and gliosis in the retina will help to develop efficient therapeutic strategies for various retinal diseases.
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Affiliation(s)
| | - Margrit Hollborn
- Department of Ophthalmology and Eye Hospital, University of Leipzig, Leipzig, Germany
| | - Andreas Bringmann
- Department of Ophthalmology and Eye Hospital, University of Leipzig, Leipzig, Germany
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Serum levels of neurotrophic factors in active toxoplasmic retinochoroiditis. Braz J Infect Dis 2016; 21:176-179. [PMID: 27932287 PMCID: PMC9427644 DOI: 10.1016/j.bjid.2016.11.005] [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: 04/11/2016] [Revised: 11/08/2016] [Accepted: 11/16/2016] [Indexed: 12/28/2022] Open
Abstract
Toxoplasmic retinochoroiditis (TR) is the most common identifiable cause of posterior uveitis in Brazil. Response to treatment and clinical presentation may vary significantly. We assessed serum levels of brain-derived neurotrophic factor (BDNF), glial cell line-derived neurotrophic factor (GDNF), nerve growth factor (NGF), neurotrophin (NT)-3, and NT-4/5 in patients with active TR, before and after TR treatment. Methods Twenty patients with active lesion and 15 healthy controls were enrolled in the study. Serum concentration of neurotrophic factors was determined by enzyme-linked immunosorbent assay. Results BDNF levels were significantly higher in patients before treatment when compared with controls (p = 0.0015). There was no significant difference in pro-BDNF, NGF, GDNF, NT-3, and NT-4/5 levels between TR patients and controls. Treatment did not affect the levels of these factors. Conclusion BDNF may be released in the context of the active TR inflammatory response.
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Mysona BA, Zhao J, Bollinger KE. Role of BDNF/TrkB pathway in the visual system: Therapeutic implications for glaucoma. EXPERT REVIEW OF OPHTHALMOLOGY 2016; 12:69-81. [PMID: 28751923 DOI: 10.1080/17469899.2017.1259566] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
INTRODUCTION Neuroprotective therapeutics are needed to treat glaucoma, an optic neuropathy that results in death of retinal ganglion cells (RGCs). AREAS COVERED The BDNF/TrkB pathway is important for RGC survival. Temporal and spatial alterations in the BDNF/TrkB pathway occur in development and in response to acute optic nerve injury and to glaucoma. In animal models, BDNF supplementation is successful at slowing RGC death after acute optic nerve injury and in glaucoma, however, the BDNF/TrkB signaling is not the only pathway supporting long term RGC survival. EXPERT COMMENTARY Much remains to be discovered about the interaction between retrograde, anterograde, and retinal BDNF/TrkB signaling pathways in both neurons and glia. An ideal therapeutic agent for glaucoma likely has several modes of action that target multiple mechanisms of neurodegeneration including the BDNF/TrkB pathway.
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Affiliation(s)
- B A Mysona
- Augusta University Department of Cellular Biology and Anatomy, James and Jean Culver Vision Discovery Institute. Address: Augusta University Department of Cellular Biology and Anatomy, Health Sciences Campus, 1120 15th Street, Augusta, GA 30912, USA,
| | - J Zhao
- Medical College of Georgia, Department of Ophthalmology at Augusta University, James and Jean Culver Vision Discovery Institute. Address: Medical College of Georgia, Department of Ophthalmology at Augusta University, 1120 15th Street, Augusta, GA 30912, USA,
| | - K E Bollinger
- Medical College of Georgia, Department of Ophthalmology at Augusta University, Augusta University Department of Cellular Biology and Anatomy, James and Jean Culver Vision Discovery Institute. Address: Medical College of Georgia, Department of Ophthalmology at Augusta University, 1120 15th Street, Augusta, GA 30912, USA,
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Guo X, Kimura A, Azuchi Y, Akiyama G, Noro T, Harada C, Namekata K, Harada T. Caloric restriction promotes cell survival in a mouse model of normal tension glaucoma. Sci Rep 2016; 6:33950. [PMID: 27669894 PMCID: PMC5037377 DOI: 10.1038/srep33950] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Accepted: 09/06/2016] [Indexed: 12/15/2022] Open
Abstract
Glaucoma is characterized by progressive degeneration of retinal ganglion cells (RGCs) and their axons. We previously reported that loss of glutamate transporters (EAAC1 or GLAST) in mice leads to RGC degeneration that is similar to normal tension glaucoma and these animal models are useful in examining potential therapeutic strategies. Caloric restriction has been reported to increase longevity and has potential benefits in injury and disease. Here we investigated the effects of every-other-day fasting (EODF), a form of caloric restriction, on glaucomatous pathology in EAAC1−/− mice. EODF suppressed RGC death and retinal degeneration without altering intraocular pressure. Moreover, visual impairment was ameliorated with EODF, indicating the functional significance of the neuroprotective effect of EODF. Several mechanisms associated with this neuroprotection were explored. We found that EODF upregulated blood β-hydroxybutyrate levels and increased histone acetylation in the retina. Furthermore, it elevated retinal mRNA expression levels of neurotrophic factors and catalase, whereas it decreased oxidative stress levels in the retina. Our findings suggest that EODF, a safe, non-invasive, and low-cost treatment, may be available for glaucoma therapy.
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Affiliation(s)
- Xiaoli Guo
- Visual Research Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Atsuko Kimura
- Visual Research Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Yuriko Azuchi
- Visual Research Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Goichi Akiyama
- Visual Research Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Takahiko Noro
- Visual Research Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Chikako Harada
- Visual Research Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Kazuhiko Namekata
- Visual Research Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Takayuki Harada
- Visual Research Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
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Kimura A, Namekata K, Guo X, Harada C, Harada T. Neuroprotection, Growth Factors and BDNF-TrkB Signalling in Retinal Degeneration. Int J Mol Sci 2016; 17:ijms17091584. [PMID: 27657046 PMCID: PMC5037849 DOI: 10.3390/ijms17091584] [Citation(s) in RCA: 120] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Revised: 09/01/2016] [Accepted: 09/14/2016] [Indexed: 12/18/2022] Open
Abstract
Neurotrophic factors play key roles in the development and survival of neurons. The potent neuroprotective effects of neurotrophic factors, including brain-derived neurotrophic factor (BDNF), ciliary neurotrophic factor (CNTF), glial cell-line derived neurotrophic factor (GDNF) and nerve growth factor (NGF), suggest that they are good therapeutic candidates for neurodegenerative diseases. Glaucoma is a neurodegenerative disease of the eye that causes irreversible blindness. It is characterized by damage to the optic nerve, usually due to high intraocular pressure (IOP), and progressive degeneration of retinal neurons called retinal ganglion cells (RGCs). Current therapy for glaucoma focuses on reduction of IOP, but neuroprotection may also be beneficial. BDNF is a powerful neuroprotective agent especially for RGCs. Exogenous application of BDNF to the retina and increased BDNF expression in retinal neurons using viral vector systems are both effective in protecting RGCs from damage. Furthermore, induction of BDNF expression by agents such as valproic acid has also been beneficial in promoting RGC survival. In this review, we discuss the therapeutic potential of neurotrophic factors in retinal diseases and focus on the differential roles of glial and neuronal TrkB in neuroprotection. We also discuss the role of neurotrophic factors in neuroregeneration.
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Affiliation(s)
- Atsuko Kimura
- Visual Research Project, Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya-ku, Tokyo 156-8506, Japan.
| | - Kazuhiko Namekata
- Visual Research Project, Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya-ku, Tokyo 156-8506, Japan.
| | - Xiaoli Guo
- Visual Research Project, Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya-ku, Tokyo 156-8506, Japan.
| | - Chikako Harada
- Visual Research Project, Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya-ku, Tokyo 156-8506, Japan.
| | - Takayuki Harada
- Visual Research Project, Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya-ku, Tokyo 156-8506, Japan.
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Yukita M, Omodaka K, Machida S, Yasuda M, Sato K, Maruyama K, Nishiguchi KM, Nakazawa T. Brimonidine Enhances the Electrophysiological Response of Retinal Ganglion Cells through the Trk-MAPK/ERK and PI3K Pathways in Axotomized Eyes. Curr Eye Res 2016; 42:125-133. [PMID: 27314704 DOI: 10.3109/02713683.2016.1153112] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
PURPOSE To investigate changes in retinal ganglion cell (RGC) activity by measuring the positive scotopic threshold response (pSTR) of the electroretinogram (ERG) in axotomized eyes after brimonidine injection. METHODS In 50 adult Sprague-Dawley rats, the left eye was axotomized and injected with phosphate buffered saline (PBS) or brimonidine and the contralateral right eye was left untreated. Scotopic ERGs were recorded simultaneously from both eyes on days 1, 2, 3, 7, and 10 after the intravitreal injection, and the amplitude of the a- and b-waves and the pSTR were measured. Surviving RGCs in the flat-mounted retinas were counted 10 days after axotomy. In addition to brimonidine, K252a (an inhibitor of tyrosine kinase phosphorylation of the Trk receptors), U0126 (a MAPK/ERK kinase inhibitor), and LY294002 (phosphoinositide 3-kinases [PI3Ks]) were also injected intravitreally into the left eye, and ERGs were recorded using the same protocol. RESULTS The pSTR amplitude increased significantly in the axotomized eyes with brimonidine, to 122.9 ± 5.0%, 161.8 ± 8.3%, and 133.6 ± 8.1% on days 1, 2, and 3 (P < 0.01), respectively, compared to the axotomized eyes treated with PBS (control). The increased pSTR amplitude returned to normal (103.6 ± 6.7%) on day 7, although there were a greater number of surviving RGCs in the treatment groups than in the controls. The intravitreal injection of K252a, U0126, or LY294002 significantly attenuated the increase in pSTR induced by intravitreal brimonidine (P < 0.01). CONCLUSION Intravitreal brimonidine enhanced the survival and electrophysiological activity of the RGCs in rats. The mechanism of this electrophysiological change may involve activation of the Trk-MAPK/ERK and Trk-PI3K signals.
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Affiliation(s)
- Masayoshi Yukita
- a Department of Ophthalmology , Tohoku University Graduate School of Medicine , Sendai , Japan
| | - Kazuko Omodaka
- a Department of Ophthalmology , Tohoku University Graduate School of Medicine , Sendai , Japan
| | - Shigeki Machida
- b Department of Ophthalmology , Koshigaya Hospital, Dokkyo Medical University , Koshigaya , Japan.,c Department of Ophthalmology , Iwate Medical University School of Medicine , Morioka , Japan
| | - Masayuki Yasuda
- a Department of Ophthalmology , Tohoku University Graduate School of Medicine , Sendai , Japan
| | - Kota Sato
- a Department of Ophthalmology , Tohoku University Graduate School of Medicine , Sendai , Japan
| | - Kazuichi Maruyama
- a Department of Ophthalmology , Tohoku University Graduate School of Medicine , Sendai , Japan
| | - Koji M Nishiguchi
- d Department of Advanced Ophthalmic Medicine , Tohoku University Graduate School of Medicine , Sendai , Japan
| | - Toru Nakazawa
- a Department of Ophthalmology , Tohoku University Graduate School of Medicine , Sendai , Japan.,d Department of Advanced Ophthalmic Medicine , Tohoku University Graduate School of Medicine , Sendai , Japan.,e Department of Retinal Disease Control , Tohoku University Graduate School of Medicine , Sendai , Japan
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Retinal Cell Degeneration in Animal Models. Int J Mol Sci 2016; 17:ijms17010110. [PMID: 26784179 PMCID: PMC4730351 DOI: 10.3390/ijms17010110] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Revised: 12/25/2015] [Accepted: 01/08/2016] [Indexed: 01/01/2023] Open
Abstract
The aim of this review is to provide an overview of various retinal cell degeneration models in animal induced by chemicals (N-methyl-d-aspartate- and CoCl2-induced), autoimmune (experimental autoimmune encephalomyelitis), mechanical stress (optic nerve crush-induced, light-induced) and ischemia (transient retinal ischemia-induced). The target regions, pathology and proposed mechanism of each model are described in a comparative fashion. Animal models of retinal cell degeneration provide insight into the underlying mechanisms of the disease, and will facilitate the development of novel effective therapeutic drugs to treat retinal cell damage.
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