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Cooper ML, Calkins DJ. Beyond hypertrophy: Changing views of astrocytes in glaucoma. Vision Res 2024; 223:108461. [PMID: 39059109 DOI: 10.1016/j.visres.2024.108461] [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: 05/23/2024] [Revised: 07/11/2024] [Accepted: 07/15/2024] [Indexed: 07/28/2024]
Abstract
Astrocytes serve multiple roles in helping to maintain homeostatic physiology of central nervous system tissue, ranging from metabolic support to coupling between vascular and neural elements. Astrocytes are especially critical in axonal tracts such as the optic nerve, where axons propagate energy-demanding action potentials great distances. In disease, astrocyte remodeling is a dynamic, multifaceted process that is often over-simplified between states of quiescence and reactivity. In glaucoma, axon degeneration in the optic nerve is characterized by progressive stages. So too is astrocyte remodeling. Here, using quantitative analysis of light and electron micrographs of myelinated optic nerve sections from the DBA/2J mouse model of glaucoma, we offer further insight into how astrocyte organization reflects stages of degeneration. This analysis indicates that even as axons degenerate, astrocyte gliosis in the nerve increases without abject proliferation, similar to results in the DBA/2J retina. Gliosis is accompanied by reorganization. As axons expand prior to frank degeneration, astrocyte processes retract from the extra-axonal space and reorient towards the nerve edge. After a critical threshold of expansion, axons drop out, and astrocyte processes distribute more evenly across the nerve reflecting gliosis. This multi-stage process likely reflects local rather than global cues from axons and the surrounding tissue that induce rapid reorganization to promote axon survival and extend functionality of the nerve.
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Affiliation(s)
- Melissa L Cooper
- Neuroscience Institute, NYU Grossman School of Medicine, New York, NY, USA
| | - David J Calkins
- Department of Ophthalmology and Visual Sciences, Vanderbilt University Medical Center, Nashville, TN, USA.
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2
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Waxman S, Schilpp H, Linton A, Jakobs TC, Sigal IA. Morphological comparison of astrocytes in the lamina cribrosa and glial lamina. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.09.07.610493. [PMID: 39314351 PMCID: PMC11418941 DOI: 10.1101/2024.09.07.610493] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 09/25/2024]
Abstract
Purpose Although the mechanisms underlying glaucomatous neurodegeneration are not yet well understood, cellular and small animal models suggest that LC astrocytes undergo early morphologic and functional changes, indicating their role as early responders to glaucomatous stress. These models, however, lack the LC found in larger animals and humans, leaving the in situ morphology of LC astrocytes and their role in glaucoma initiation underexplored. In this work, we aimed to characterize the morphology of LC astrocytes in situ and determine differences and similarities with astrocytes in the mouse glial lamina (GL), the analogous structure in a prominent glaucoma model. Methods Astrocytes in the LCs of twenty-two eyes from goats, sheep, and pigs were stochastically labeled via Multicolor DiOlistics and imaged in situ using confocal microscopy. 3D models of DiOlistically-labeled LC astrocytes and hGFAPpr-GFP mouse GL astrocytes were constructed to quantify morphological features related to astrocyte functions. LC and GL astrocyte cross-pore contacts, branching complexity, branch tortuosity, and cell and branch span were compared. Results LC astrocytes displayed distinct spatial relationships with collagen, greater branching complexity, and higher branch tortuosity compared to GL astrocytes. Despite substantial differences in their anatomical environments, LC and GL astrocytes had similar cell and branch spans. Conclusions Astrocyte morphology in the LC was characterized through Multicolor DiOlistic labeling. LC and GL astrocytes have both distinct and shared morphological features. Further research is needed to understand the potentially unique roles of LC astrocytes in glaucoma initiation and progression.
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Qian Z, Jiao M, Zhang N, Tang X, Liu S, Zhang F, Wang C, Zheng F. The IL-33/ST2 Axis Protects Retinal Ganglion Cells by Modulating the Astrocyte Response After Optic Nerve Injury. Neurosci Bull 2024:10.1007/s12264-024-01279-y. [PMID: 39190095 DOI: 10.1007/s12264-024-01279-y] [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: 12/11/2023] [Accepted: 04/29/2024] [Indexed: 08/28/2024] Open
Abstract
IL-33 and its receptor ST2 play crucial roles in tissue repair and homeostasis. However, their involvement in optic neuropathy due to trauma and glaucoma remains unclear. Here, we report that IL-33 and ST2 were highly expressed in the mouse optic nerve and retina. Deletion of IL-33 or ST2 exacerbated retinal ganglion cell (RGC) loss, retinal thinning, and nerve fiber degeneration following optic nerve (ON) injury. This heightened retinal neurodegeneration correlated with increased neurotoxic astrocytes in Il33-/- mice. In vitro, rIL-33 mitigated the neurotoxic astrocyte phenotype and reduced the expression of pro-inflammatory factors, thereby alleviating the RGC death induced by neurotoxic astrocyte-conditioned medium in retinal explants. Exogenous IL-33 treatment improved RGC survival in Il33-/- and WT mice after ON injury, but not in ST2-/- mice. Our findings highlight the role of the IL-33/ST2 axis in modulating reactive astrocyte function and providing neuroprotection for RGCs following ON injury.
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Affiliation(s)
- Zhigang Qian
- Department of Immunology, School of Basic Medicine, Tongji Medical College and State Key Laboratory for Diagnosis and Treatment of Severe Zoonotic Infectious Diseases, Huazhong University of Science and Technology, Wuhan, 430030, China
- Department of Ophthalmology, Xiangyang Central Hospital, Affiliated Hospital of Hubei University of Arts and Science, Xiangyang, 441000, China
| | - Mengya Jiao
- Department of Immunology, School of Basic Medicine, Tongji Medical College and State Key Laboratory for Diagnosis and Treatment of Severe Zoonotic Infectious Diseases, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Na Zhang
- Department of Immunology, School of Basic Medicine, Tongji Medical College and State Key Laboratory for Diagnosis and Treatment of Severe Zoonotic Infectious Diseases, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Xuhuan Tang
- Department of Immunology, School of Basic Medicine, Tongji Medical College and State Key Laboratory for Diagnosis and Treatment of Severe Zoonotic Infectious Diseases, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Shiwang Liu
- Department of Immunology, School of Basic Medicine, Tongji Medical College and State Key Laboratory for Diagnosis and Treatment of Severe Zoonotic Infectious Diseases, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Feng Zhang
- Department of Immunology, School of Basic Medicine, Tongji Medical College and State Key Laboratory for Diagnosis and Treatment of Severe Zoonotic Infectious Diseases, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Chenchen Wang
- National Demonstration Center for Experimental Basic Medical Education, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Fang Zheng
- Department of Immunology, School of Basic Medicine, Tongji Medical College and State Key Laboratory for Diagnosis and Treatment of Severe Zoonotic Infectious Diseases, Huazhong University of Science and Technology, Wuhan, 430030, China.
- Key Laboratory of Organ Transplantation, Ministry of Education, NHC Key Laboratory of Organ Transplantation, Key Laboratory of Organ Transplantation, Chinese Academy of Medical Sciences, Wuhan, 430030, China.
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Hameed SS, Bodi NE, Miller RC, Sharma TP. Neuritin 1 Drives Therapeutic Preservation of Retinal Ganglion Cells in an Ex Vivo Human Glaucoma Model. J Ocul Pharmacol Ther 2024. [PMID: 38995841 DOI: 10.1089/jop.2024.0041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/14/2024] Open
Abstract
Purpose: Glaucoma is a leading cause of irreversible blindness. Glaucomatous intraocular pressure (IOP) triggers deleterious effects, including gliosis, optic nerve (ON) axonal retraction, neurotrophic factor deprivation, inflammation, and other pathological events, leading to retinal ganglion cell (RGC) loss. Trophic factor impairment enhances RGC apoptosis susceptibility. Neuritin 1 (NRN1), a neurotrophic protein downstream of various neurotrophins, exhibited RGC protection and regeneration in axotomy models. We evaluated human recombinant NRN1's impact on human RGCs cultured in pressurized conditions within the ex vivo translaminar autonomous system to simulate glaucoma pathogenesis. Methods: Human glaucomatous and non-glaucomatous donor eyes were obtained from eye banks according to the Declaration of Helsinki. Initially, we evaluated NRN1and RGC marker expression in glaucoma and non-glaucomatous retina to determine the NRN1 level and its association with RGC loss. Further, we evaluated NRN1's therapeutic potential by treating pressurized human eyes at normal and high IOP for seven days. Retina, ON, and conditioned medium were analyzed for RGC survival (THY1, RBPMS), gliosis (GFAP), apoptosis (CASP3, CASP7), and extracellular matrix deposition (COLIV, FN) by qRT-PCR and western blotting. Paraphenylenediamine staining assessed ON axonal degeneration, whereas ex vivo electroretinogram assessed retinal activity. Results: Glaucomatous retinas exhibited significant reductions in both NRN1 (*p = 0.007, n = 5) and RGC marker expression (*p = 0.04, n = 5). NRN1 treatment reduced gliosis, extracellular matrix deposition, ON degeneration, and increased retinal activity in pressure-perfused eyes. Conclusions: Our study confirms that NRN1 enhances human RGC survival and improves retinal function in degenerative conditions, substantiating it as a promising candidate for rescuing human RGCs from degeneration.
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Affiliation(s)
- Shahna S Hameed
- Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, Indiana
| | - Nicole E Bodi
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, Indiana
| | - Ryan C Miller
- Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, Indiana
| | - Tasneem P Sharma
- Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, Indiana
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Pang Y, Hu H, Xu K, Cao T, Wang Z, Nie J, Zheng H, Luo H, Wang F, Xiong C, Deng KY, Xin HB, Zhang X. CD38 Deficiency Protects Mouse Retinal Ganglion Cells Through Activating the NAD+/Sirt1 Pathway in Ischemia-Reperfusion and Optic Nerve Crush Models. Invest Ophthalmol Vis Sci 2024; 65:36. [PMID: 38776115 PMCID: PMC11127494 DOI: 10.1167/iovs.65.5.36] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2023] [Accepted: 05/05/2024] [Indexed: 05/27/2024] Open
Abstract
Purpose The purpose of this study was to investigate the protective effect of CD38 deletion on retinal ganglion cells (RGCs) in a mouse retinal ischemia/reperfusion (I/R) model and an optic nerve crush (ONC) model, and to elucidate the underlying molecular mechanisms. Methods Retinal I/R and ONC models were constructed in mice. PCR was used to identify the deletion of CD38 gene in mice, hematoxylin and eosin (H&E) staining was used to evaluate the changes in retinal morphology, and electroretinogram (ERG) was used to evaluate the changes in retinal function. The survival of RGCs and activation of retinal macroglia were evaluated by immunofluorescence staining. The expression of Sirt1, CD38, Ac-p65, Ac-p53, TNF-α, IL-1β, and Caspase3 proteins in the retina was further evaluated by protein imprinting. Results In retinal I/R and ONC models, CD38 deficiency reduced the loss of RGCs and activation of macroglia and protected the retinal function. CD38 deficiency increased the concentration of NAD+, reduced the degree of acetylation of NF-κB p65 and p53, and reduced expression of the downstream inflammatory cytokines TNFα, IL-1β, and apoptotic protein Caspase3 in the retina in the ONC model. Intraperitoneal injection of the Sirt1 inhibitor EX-527 partially counteracted the effects of CD38 deficiency, suggesting that CD38 deficiency acts at least in part through the NAD+/Sirt1 pathway. Conclusions CD38 plays an important role in the pathogenesis of retinal I/R and ONC injury. CD38 deletion protects RGCs by attenuating inflammatory responses and apoptosis through the NAD+/Sirt1 pathway.
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Affiliation(s)
- Yulian Pang
- Affiliated Eye Hospital of Nanchang University, Jiangxi Medical College, Nanchang University, Jiangxi Research Institute of Ophthalmology and Visual Science, Jiangxi Provincial Key Laboratory for Ophthalmology, Jiangxi Clinical Research Center for Ophthalmic Disease, Nanchang, China
| | - Haijian Hu
- Affiliated Eye Hospital of Nanchang University, Jiangxi Medical College, Nanchang University, Jiangxi Research Institute of Ophthalmology and Visual Science, Jiangxi Provincial Key Laboratory for Ophthalmology, Jiangxi Clinical Research Center for Ophthalmic Disease, Nanchang, China
| | - Ke Xu
- Affiliated Eye Hospital of Nanchang University, Jiangxi Medical College, Nanchang University, Jiangxi Research Institute of Ophthalmology and Visual Science, Jiangxi Provincial Key Laboratory for Ophthalmology, Jiangxi Clinical Research Center for Ophthalmic Disease, Nanchang, China
| | - Ting Cao
- Affiliated Eye Hospital of Nanchang University, Jiangxi Medical College, Nanchang University, Jiangxi Research Institute of Ophthalmology and Visual Science, Jiangxi Provincial Key Laboratory for Ophthalmology, Jiangxi Clinical Research Center for Ophthalmic Disease, Nanchang, China
- Department of Orthopaedics, The Fourth Medical Center of Chinese PLA General Hospital, Beijing, China
- Medical School of Chinese PLA, Beijing, China
| | - Zhiruo Wang
- Affiliated Eye Hospital of Nanchang University, Jiangxi Medical College, Nanchang University, Jiangxi Research Institute of Ophthalmology and Visual Science, Jiangxi Provincial Key Laboratory for Ophthalmology, Jiangxi Clinical Research Center for Ophthalmic Disease, Nanchang, China
- Department of Ophthalmology, The Second Xiangya Hospital of Central South University, Changsha, China
| | - Jiahe Nie
- Affiliated Eye Hospital of Nanchang University, Jiangxi Medical College, Nanchang University, Jiangxi Research Institute of Ophthalmology and Visual Science, Jiangxi Provincial Key Laboratory for Ophthalmology, Jiangxi Clinical Research Center for Ophthalmic Disease, Nanchang, China
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Haina Zheng
- Affiliated Eye Hospital of Nanchang University, Jiangxi Medical College, Nanchang University, Jiangxi Research Institute of Ophthalmology and Visual Science, Jiangxi Provincial Key Laboratory for Ophthalmology, Jiangxi Clinical Research Center for Ophthalmic Disease, Nanchang, China
| | - Hongdou Luo
- Affiliated Eye Hospital of Nanchang University, Jiangxi Medical College, Nanchang University, Jiangxi Research Institute of Ophthalmology and Visual Science, Jiangxi Provincial Key Laboratory for Ophthalmology, Jiangxi Clinical Research Center for Ophthalmic Disease, Nanchang, China
| | - Feifei Wang
- Affiliated Eye Hospital of Nanchang University, Jiangxi Medical College, Nanchang University, Jiangxi Research Institute of Ophthalmology and Visual Science, Jiangxi Provincial Key Laboratory for Ophthalmology, Jiangxi Clinical Research Center for Ophthalmic Disease, Nanchang, China
| | - Chan Xiong
- Affiliated Eye Hospital of Nanchang University, Jiangxi Medical College, Nanchang University, Jiangxi Research Institute of Ophthalmology and Visual Science, Jiangxi Provincial Key Laboratory for Ophthalmology, Jiangxi Clinical Research Center for Ophthalmic Disease, Nanchang, China
| | - Ke-Yu Deng
- Institute of Translational Medicine, Nanchang University, Nanchang, China
| | - Hong-Bo Xin
- Institute of Translational Medicine, Nanchang University, Nanchang, China
| | - Xu Zhang
- Affiliated Eye Hospital of Nanchang University, Jiangxi Medical College, Nanchang University, Jiangxi Research Institute of Ophthalmology and Visual Science, Jiangxi Provincial Key Laboratory for Ophthalmology, Jiangxi Clinical Research Center for Ophthalmic Disease, Nanchang, China
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Hariani HN, Ghosh AK, Rosen SM, Tso HY, Kessinger C, Zhang C, Jones WK, Sappington RM, Mitchell CH, Stubbs EB, Rao VR, Kaja S. Lysyl oxidase like-1 deficiency in optic nerve head astrocytes elicits reactive astrocytosis and alters functional effects of astrocyte derived exosomes. Exp Eye Res 2024; 240:109813. [PMID: 38331016 PMCID: PMC10962968 DOI: 10.1016/j.exer.2024.109813] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2023] [Revised: 01/27/2024] [Accepted: 01/29/2024] [Indexed: 02/10/2024]
Abstract
Glaucoma is a multifactorial progressive ocular pathology that manifests clinically with damage to the optic nerve (ON) and the retina, ultimately leading to blindness. The optic nerve head (ONH) shows the earliest signs of glaucoma pathology, and therefore, is an attractive target for drug discovery. The goal of this study was to elucidate the effects of reactive astrocytosis on the elastin metabolism pathway in primary rat optic nerve head astrocytes (ONHA), the primary glial cell type in the unmyelinated ONH. Following exposure to static equibiaxial mechanical strain, we observed prototypic molecular and biochemical signatures of reactive astrocytosis that were associated with a decrease in lysyl oxidase like 1 (Loxl1) expression and a concomitant decrease in elastin (Eln) gene expression. We subsequently investigated the role of Loxl1 in reactive astrocytosis by generating primary rat ONHA cultures with ∼50% decreased Loxl1 expression. Our results suggest that reduced Loxl1 expression is sufficient to elicit molecular signatures of elastinopathy in ONHA. Astrocyte derived exosomes (ADE) significantly increased the length of primary neurites of primary neurons in vitro. In contrast, ADE from Loxl1-deficient ONHA were deficient of trophic effects on neurite outgrowth in vitro, positing that Loxl1 dysfunction and the ensuing impaired elastin synthesis during reactive astrocytosis in the ONH may contribute to impaired neuron-glia signaling in glaucoma. Our data support a role of dysregulated Loxl1 function in eliciting reactive astrocytosis in glaucoma subtypes associated with increased IOP, even in the absence of genetic polymorphisms in LOXL1 typically associated with exfoliation glaucoma. This suggests the need for a paradigm shift toward considering lysyl oxidase activity and elastin metabolism and signaling as contributors to an altered secretome of the ONH that may lead to the progression of glaucomatous changes. Future research is needed to investigate cargo of exosomes in the context of reactive astrocytosis and identify the pathways leading to the observed transcriptome changes during reactive astrocytosis.
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Affiliation(s)
- Harsh N Hariani
- Graduate Program in Neuroscience, Loyola University Chicago, Maywood, IL, 60153, USA; Research Service, Edward Hines Jr Veterans Affairs Hospital, Hines, IL, 60141, USA
| | - Anita K Ghosh
- Graduate Program in Neuroscience, Loyola University Chicago, Maywood, IL, 60153, USA; Research Service, Edward Hines Jr Veterans Affairs Hospital, Hines, IL, 60141, USA
| | - Sasha M Rosen
- Department of Ophthalmology, Loyola University Chicago, Maywood, IL, 60153, USA; Department of Radiology, UC Davis Medical Center, Sacramento, CA, 95817, USA
| | - Huen-Yee Tso
- Basic and Translational Sciences, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Cassidy Kessinger
- Graduate Program in Neuroscience, Loyola University Chicago, Maywood, IL, 60153, USA
| | - Chongyu Zhang
- Graduate Program in Molecular Pharmacology and Therapeutics, Loyola University Chicago, Maywood, IL, 60153, USA
| | - W Keith Jones
- Department of Molecular Pharmacology and Neuroscience, Loyola University Chicago, Maywood, IL, 60153, USA
| | - Rebecca M Sappington
- Department of Biochemistry, Wake Forest University School of Medicine, Winston-Salem, NC, 27109, USA; Translational Eye and Vision Research Center, Wake Forest University School of Medicine, Winston-Salem, NC, 27109, USA
| | - Claire H Mitchell
- Basic and Translational Sciences, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Evan B Stubbs
- Department of Ophthalmology, Loyola University Chicago, Maywood, IL, 60153, USA; Research Service, Edward Hines Jr Veterans Affairs Hospital, Hines, IL, 60141, USA
| | - Vidhya R Rao
- Department of Ophthalmology, Loyola University Chicago, Maywood, IL, 60153, USA; Research Service, Edward Hines Jr Veterans Affairs Hospital, Hines, IL, 60141, USA
| | - Simon Kaja
- Department of Ophthalmology, Loyola University Chicago, Maywood, IL, 60153, USA; Department of Molecular Pharmacology and Neuroscience, Loyola University Chicago, Maywood, IL, 60153, USA; Research Service, Edward Hines Jr Veterans Affairs Hospital, Hines, IL, 60141, USA.
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7
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Liu HH, Cullen PF, Sivak JM, Gronert K, Flanagan JG. Protective Effects of Lipoxin A 4 and B 4 Signaling on the Inner Retina in a Mouse Model of Experimental Glaucoma. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.17.575414. [PMID: 38293224 PMCID: PMC10827219 DOI: 10.1101/2024.01.17.575414] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2024]
Abstract
Glaucoma is a common neurodegenerative disease characterized by progressive degeneration of retinal ganglion cells (RGCs) and the retinal nerve fiber layer (RNFL), resulting in a gradual decline of vision. A recent study by our groups indicated that the levels of lipoxins A4 (LXA4) and B4 (LXB4) in the retina and optic nerve decrease following acute injury, and that restoring their function is neuroprotective. Lipoxins are members of the specialized pro-resolving mediator (SPM) family and play key roles to mitigate and resolve chronic inflammation and tissue damage. Yet, knowledge about lipoxin neuroprotective activity remains limited. Here we investigate the in vivo efficacy of exogenous LXA4 and LXB4 administration on the inner retina in a mouse model of chronic experimental glaucoma. To investigate the contribution of LXA4 signaling we used transgenic knockout (KO) mice lacking the two mouse LXA4 receptors (Fpr2/Fpr3-/-). Functional and structural changes of inner retinal neurons were assessed longitudinally using electroretinogram (ERG) and optical coherence tomography (OCT). At the end of the experiment, retinal samples were harvested for immunohistological assessment. While both lipoxins generated protective trends, only LXB4 treatment was significant, and consistently more efficacious than LXA4 in all endpoints. Both lipoxins also appeared to dramatically reduce Müller glial reactivity following injury. In comparison, Fpr2/Fpr3 deletion significantly worsened inner retinal injury and function, consistent with an essential protective role for endogenous LXA4. Together, these results support further exploration of lipoxin signaling as a treatment for glaucomatous neurodegeneration.
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Affiliation(s)
- Hsin-Hua Liu
- Herbert Wertheim School of Optometry and Vision Science, University of California at Berkeley, Berkeley, California, United States
| | - Paul F. Cullen
- Herbert Wertheim School of Optometry and Vision Science, University of California at Berkeley, Berkeley, California, United States
| | - Jeremy M. Sivak
- Department of Ophthalmology and Vision Science, University of Toronto, Toronto, Ontario, Canada
- Krembil Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Karsten Gronert
- Herbert Wertheim School of Optometry and Vision Science, University of California at Berkeley, Berkeley, California, United States
| | - John G. Flanagan
- Herbert Wertheim School of Optometry and Vision Science, University of California at Berkeley, Berkeley, California, United States
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Shinozaki Y, Namekata K, Guo X, Harada T. Glial cells as a promising therapeutic target of glaucoma: beyond the IOP. FRONTIERS IN OPHTHALMOLOGY 2024; 3:1310226. [PMID: 38983026 PMCID: PMC11182302 DOI: 10.3389/fopht.2023.1310226] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Accepted: 12/18/2023] [Indexed: 07/11/2024]
Abstract
Glial cells, a type of non-neuronal cell found in the central nervous system (CNS), play a critical role in maintaining homeostasis and regulating CNS functions. Recent advancements in technology have paved the way for new therapeutic strategies in the fight against glaucoma. While intraocular pressure (IOP) is the most well-known modifiable risk factor, a significant number of glaucoma patients have normal IOP levels. Because glaucoma is a complex, multifactorial disease influenced by various factors that contribute to its onset and progression, it is imperative that we consider factors beyond IOP to effectively prevent or slow down the disease's advancement. In the realm of CNS neurodegenerative diseases, glial cells have emerged as key players due to their pivotal roles in initiating and hastening disease progression. The inhibition of dysregulated glial function holds the potential to protect neurons and restore brain function. Consequently, glial cells represent an enticing therapeutic candidate for glaucoma, even though the majority of glaucoma research has historically concentrated solely on retinal ganglion cells (RGCs). In addition to the neuroprotection of RGCs, the proper regulation of glial cell function can also facilitate structural and functional recovery in the retina. In this review, we offer an overview of recent advancements in understanding the non-cell-autonomous mechanisms underlying the pathogenesis of glaucoma. Furthermore, state-of-the-art technologies have opened up possibilities for regenerating the optic nerve, which was previously believed to be incapable of regeneration. We will also delve into the potential roles of glial cells in the regeneration of the optic nerve and the restoration of visual function.
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Affiliation(s)
- Youichi Shinozaki
- Visual Research Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Kazuhiko Namekata
- Visual Research Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Xiaoli Guo
- 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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9
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Rozpędek-Kamińska W, Galita G, Saramowicz K, Granek Z, Barczuk J, Siwecka N, Pytel D, Majsterek I. Evaluation of the LDN-0060609 PERK Inhibitor as a Selective Treatment for Primary Open-Angle Glaucoma: An In Vitro Study on Human Retinal Astrocytes. Int J Mol Sci 2024; 25:728. [PMID: 38255802 PMCID: PMC10815359 DOI: 10.3390/ijms25020728] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Revised: 12/23/2023] [Accepted: 01/03/2024] [Indexed: 01/24/2024] Open
Abstract
The term glaucoma encompasses various neurodegenerative eye disorders, among which the most common is primary open-angle glaucoma (POAG). Recently, the essential role of human retinal astrocytes (HRA) in glaucoma progression has been placed in the spotlight. It has been found that placing the endoplasmic reticulum (ER) under stress and activating PERK leads to apoptosis of HRA cells, which inhibits their neuroprotective effect in the course of glaucoma. Therefore, the aim of the present study was to evaluate the effectiveness of the small-molecule PERK inhibitor LDN-0060609 in countering ER stress conditions induced in HRA cells in vitro. The activity of LDN-0060609 was studied in terms of protein and mRNA expression, cytotoxicity, genotoxicity, caspase-3 level and cell cycle progression. LDN-0060609 at 25 μM proved to be a potent inhibitor of the major PERK substrate, p-eIF2α (49% inhibition). The compound markedly decreased the expression of pro-apoptotic ER stress-related genes (ATF4, DDIT3, BAX and Bcl-2). Treatment with LDN-0060609 significantly increased cell viability, decreased genotoxicity and caspase-3 levels, and restored cell cycle distribution in HRA cells with activated ER stress conditions. These findings indicate that the small-molecule PERK inhibitor LDN-0060609 can potentially be developed into a novel anti-glaucoma agent.
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Affiliation(s)
- Wioletta Rozpędek-Kamińska
- Department of Clinical Chemistry and Biochemistry, Medical University of Lodz, 90-419 Lodz, Poland; (W.R.-K.); (G.G.); (K.S.); (Z.G.); (J.B.); (N.S.)
| | - Grzegorz Galita
- Department of Clinical Chemistry and Biochemistry, Medical University of Lodz, 90-419 Lodz, Poland; (W.R.-K.); (G.G.); (K.S.); (Z.G.); (J.B.); (N.S.)
| | - Kamil Saramowicz
- Department of Clinical Chemistry and Biochemistry, Medical University of Lodz, 90-419 Lodz, Poland; (W.R.-K.); (G.G.); (K.S.); (Z.G.); (J.B.); (N.S.)
| | - Zuzanna Granek
- Department of Clinical Chemistry and Biochemistry, Medical University of Lodz, 90-419 Lodz, Poland; (W.R.-K.); (G.G.); (K.S.); (Z.G.); (J.B.); (N.S.)
| | - Julia Barczuk
- Department of Clinical Chemistry and Biochemistry, Medical University of Lodz, 90-419 Lodz, Poland; (W.R.-K.); (G.G.); (K.S.); (Z.G.); (J.B.); (N.S.)
| | - Natalia Siwecka
- Department of Clinical Chemistry and Biochemistry, Medical University of Lodz, 90-419 Lodz, Poland; (W.R.-K.); (G.G.); (K.S.); (Z.G.); (J.B.); (N.S.)
| | - Dariusz Pytel
- Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, SC 29425, USA;
| | - Ireneusz Majsterek
- Department of Clinical Chemistry and Biochemistry, Medical University of Lodz, 90-419 Lodz, Poland; (W.R.-K.); (G.G.); (K.S.); (Z.G.); (J.B.); (N.S.)
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Korneva A, Kimball EC, Johnson TV, Quillen SE, Pease ME, Quigley HA, Nguyen TD. Comparison of the Biomechanics of the Mouse Astrocytic Lamina Cribrosa Between Glaucoma and Optic Nerve Crush Models. Invest Ophthalmol Vis Sci 2023; 64:14. [PMID: 38088825 PMCID: PMC10720758 DOI: 10.1167/iovs.64.15.14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Accepted: 11/14/2023] [Indexed: 12/17/2023] Open
Abstract
Purpose The strain response of the mouse astrocytic lamina (AL) to an ex vivo mechanical test was compared between two protocols: eyes that underwent sustained intraocular pressure (IOP) increase and eyes after optic nerve crush. Methods Chronic IOP elevation was induced by microbead injection or the optic nerve was crushed in mice with widespread green fluorescence. After 3 days or 6 weeks, eyes were inflation tested by a published method of two-photon fluorescence to image the AL. Digital volume correlation was used to calculate strains. Optic nerve axon damage was also evaluated. Results In the central AL but not the peripheral AL, four strains were greater in eyes at the 3-day glaucoma time point than control (P from 0.029 to 0.049, n = 8 eyes per group). Also, at this time point, five strains were greater in the central AL compared to the peripheral AL (P from 0.041 to 0.00003). At the 6-week glaucoma time point, the strains averaged across the specimen, in the central AL, and the peripheral AL were indistinguishable from the respective controls. Strains were not significantly different between controls and eyes 3 days or 6 weeks after crush (n = 8 and 16). Conclusions We found alterations in the ex vivo mechanical behavior in eyes from mice with experimental glaucoma but not in those with crushed optic nerves. The results of this study demonstrate that significant axon injury does not directly affect mechanical behavior of the astrocytic lamina.
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Affiliation(s)
- Arina Korneva
- Glaucoma Center of Excellence, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
| | - Elizabeth C. Kimball
- Glaucoma Center of Excellence, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
| | - Thomas V. Johnson
- Glaucoma Center of Excellence, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
| | - Sarah E. Quillen
- Glaucoma Center of Excellence, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
| | - Mary E. Pease
- Glaucoma Center of Excellence, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
| | - Harry A. Quigley
- Glaucoma Center of Excellence, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
| | - Thao D. Nguyen
- Glaucoma Center of Excellence, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
- Department of Mechanical Engineering, The Johns Hopkins University, Baltimore, Maryland, United States
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11
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Huang L, Hong Y, Fu X, Tan H, Chen Y, Wang Y, Chen D. The role of the microbiota in glaucoma. Mol Aspects Med 2023; 94:101221. [PMID: 37866106 DOI: 10.1016/j.mam.2023.101221] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2023] [Revised: 10/10/2023] [Accepted: 10/12/2023] [Indexed: 10/24/2023]
Abstract
Glaucoma is a common irreversible vision loss disorder because of the gradual loss of retinal ganglion cells (RGCs) and the optic nerve axons. Major risk factors include elder age and high intraocular pressure (IOP). However, high IOP is neither necessary nor sufficient to cause glaucoma. Some non-IOP signaling cascades can mediate RGC degeneration. In addition, gender, diet, obesity, depression, or anxiety also contribute to the development of glaucoma. Understanding the mechanism of glaucoma development is crucial for timely diagnosis and establishing new strategies to improve current IOP-reducing therapies. The microbiota exerts a marked influence on the human body during homeostasis and disease. Many glaucoma patients have abnormal compositions of the microbiota (dysbiosis) in multiple locations, including the ocular surface, intraocular cavity, oral cavity, stomach, and gut. Here, we discuss findings in the last ten years or more about the microbiota and metabolite changes in animal models, patients with three risk factors (aging, obesity, and depression), and glaucoma patients. Antigenic mimicry and heat stress protein (HSP)-specific T-cell infiltration in the retina may be responsible for commensal microbes contributing to glaucomatous RGC damage. LPS-TLR4 pathway may be the primary mechanism of oral and ocular surface dysbiosis affecting glaucoma. Microbe-derived metabolites may also affect glaucoma pathogenesis. Homocysteine accumulation, inflammatory factor release, and direct dissemination may link gastric H. pylori infection and anterior chamber viral infection (such as cytomegalovirus) to glaucoma. Potential therapeutic protocols targeting microbiota include antibiotics, modified diet, and stool transplant. Later investigations will uncover the underlying molecular mechanism connecting dysbiosis to glaucoma and its clinical applications in glaucoma management.
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Affiliation(s)
- Ling Huang
- The Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu, 610041, China; The Research Laboratory of Ophthalmology and Vision Sciences, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Yiwen Hong
- The Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu, 610041, China; The Research Laboratory of Ophthalmology and Vision Sciences, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Xiangyu Fu
- The Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu, 610041, China; The Research Laboratory of Ophthalmology and Vision Sciences, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Haishan Tan
- The Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu, 610041, China; The Research Laboratory of Ophthalmology and Vision Sciences, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Yongjiang Chen
- The School of Optometry and Vision Science, University of Waterloo, 200 University Ave. W., Waterloo, ON, N2L 3G1, Canada
| | - Yujiao Wang
- The Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu, 610041, China; The Research Laboratory of Ophthalmology and Vision Sciences, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, 610041, China.
| | - Danian Chen
- The Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu, 610041, China; The Research Laboratory of Ophthalmology and Vision Sciences, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, 610041, China.
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12
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Zaidi SAH, Xu Z, Lemtalsi T, Sandow P, Athota S, Liu F, Haigh S, Huo Y, Narayanan SP, Fulton DJR, Rojas MA, Fouda AY, Caldwell RW, Caldwell RB. Calbindin 2-specific deletion of arginase 2 preserves visual function after optic nerve crush. Cell Death Dis 2023; 14:661. [PMID: 37816735 PMCID: PMC10564748 DOI: 10.1038/s41419-023-06180-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 09/12/2023] [Accepted: 09/26/2023] [Indexed: 10/12/2023]
Abstract
We previously found that global deletion of the mitochondrial enzyme arginase 2 (A2) limits optic nerve crush (ONC)-induced neuronal death. Herein, we examined the cell-specific role of A2 in this pathology by studies using wild type (WT), neuronal-specific calbindin 2 A2 KO (Calb2cre/+ A2 f/f), myeloid-specific A2 KO (LysMcre/+ A2f/f), endothelial-specific A2 KO (Cdh5cre/+ A2f/f), and floxed controls. We also examined the impact of A2 overexpression on mitochondrial function in retinal neuronal R28 cells. Immunolabeling showed increased A2 expression in ganglion cell layer (GCL) neurons of WT mice within 6 h-post injury and inner retinal neurons after 7 days. Calb2 A2 KO mice showed improved neuronal survival, decreased TUNEL-positive neurons, and improved retinal function compared to floxed littermates. Neuronal loss was unchanged by A2 deletion in myeloid or endothelial cells. We also found increased expression of neurotrophins (BDNF, FGF2) and improved survival signaling (pAKT, pERK1/2) in Calb2 A2 KO retinas within 24-hour post-ONC along with suppression of inflammatory mediators (IL1β, TNFα, IL6, and iNOS) and apoptotic markers (cleavage of caspase3 and PARP). ONC increased GFAP and Iba1 immunostaining in floxed controls, and Calb2 A2 KO dampened this effect. Overexpression of A2 in R28 cells increased Drp1 expression, and decreased mitochondrial respiration, whereas ABH-induced inhibition of A2 decreased Drp1 expression and improved mitochondrial respiration. Finally, A2 overexpression or excitotoxic treatment with glutamate significantly impaired mitochondrial function in R28 cells as shown by significant reductions in basal respiration, maximal respiration, and ATP production. Further, glutamate treatment of A2 overexpressing cells did not induce further deterioration in their mitochondrial function, indicating that A2 overexpression or glutamate insult induce comparable alterations in mitochondrial function. Our data indicate that neuronal A2 expression is neurotoxic after injury, and A2 deletion in Calb2 expressing neurons limits ONC-induced retinal neurodegeneration and improves visual function.
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Affiliation(s)
- Syed A H Zaidi
- Vascular Biology Center, Augusta University, Augusta, GA, 30912, USA.
- Department of Medicine, Augusta University, Augusta, GA, 30912, USA.
- James and Jean Culver Vision Discovery Institute, Augusta University, Augusta, GA, 30912, USA.
| | - Zhimin Xu
- Vascular Biology Center, Augusta University, Augusta, GA, 30912, USA
- James and Jean Culver Vision Discovery Institute, Augusta University, Augusta, GA, 30912, USA
| | - Tahira Lemtalsi
- Vascular Biology Center, Augusta University, Augusta, GA, 30912, USA
- James and Jean Culver Vision Discovery Institute, Augusta University, Augusta, GA, 30912, USA
| | - Porsche Sandow
- James and Jean Culver Vision Discovery Institute, Augusta University, Augusta, GA, 30912, USA
- Department of Pharmacology and Toxicology, Augusta University, Augusta, GA, 30912, USA
| | - Sruthi Athota
- Vascular Biology Center, Augusta University, Augusta, GA, 30912, USA
| | - Fang Liu
- James and Jean Culver Vision Discovery Institute, Augusta University, Augusta, GA, 30912, USA
- Research Division, Charlie Norwood VA Medical Center, Augusta, GA, 30904, USA
| | - Stephen Haigh
- Vascular Biology Center, Augusta University, Augusta, GA, 30912, USA
| | - Yuqing Huo
- Vascular Biology Center, Augusta University, Augusta, GA, 30912, USA
- James and Jean Culver Vision Discovery Institute, Augusta University, Augusta, GA, 30912, USA
- Department of Cellular Biology and Anatomy, Augusta University, Augusta, GA, 30912, USA
| | - S Priya Narayanan
- Vascular Biology Center, Augusta University, Augusta, GA, 30912, USA
- James and Jean Culver Vision Discovery Institute, Augusta University, Augusta, GA, 30912, USA
- Research Division, Charlie Norwood VA Medical Center, Augusta, GA, 30904, USA
- Department of Cellular Biology and Anatomy, Augusta University, Augusta, GA, 30912, USA
- Program in Clinical and Experimental Therapeutics, College of Pharmacy, University of Georgia, Augusta, GA, 30912, USA
| | - David J R Fulton
- Vascular Biology Center, Augusta University, Augusta, GA, 30912, USA
- Department of Pharmacology and Toxicology, Augusta University, Augusta, GA, 30912, USA
| | - Modesto A Rojas
- Vascular Biology Center, Augusta University, Augusta, GA, 30912, USA
- James and Jean Culver Vision Discovery Institute, Augusta University, Augusta, GA, 30912, USA
- Department of Pharmacology and Toxicology, Augusta University, Augusta, GA, 30912, USA
| | - Abdelrahman Y Fouda
- Vascular Biology Center, Augusta University, Augusta, GA, 30912, USA
- James and Jean Culver Vision Discovery Institute, Augusta University, Augusta, GA, 30912, USA
- Department of Pharmacology and Toxicology, University of Arkansas for Medical Sciences, Little Rock, AR, 72205, USA
| | - Robert W Caldwell
- James and Jean Culver Vision Discovery Institute, Augusta University, Augusta, GA, 30912, USA
- Department of Pharmacology and Toxicology, Augusta University, Augusta, GA, 30912, USA
| | - Ruth B Caldwell
- Vascular Biology Center, Augusta University, Augusta, GA, 30912, USA.
- James and Jean Culver Vision Discovery Institute, Augusta University, Augusta, GA, 30912, USA.
- Department of Cellular Biology and Anatomy, Augusta University, Augusta, GA, 30912, USA.
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13
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Mazumder AG, Julé AM, Sun D. Astrocytes of the optic nerve exhibit a region-specific and temporally distinct response to elevated intraocular pressure. Mol Neurodegener 2023; 18:68. [PMID: 37759301 PMCID: PMC10523752 DOI: 10.1186/s13024-023-00658-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Accepted: 09/15/2023] [Indexed: 09/29/2023] Open
Abstract
BACKGROUND The optic nerve is an important tissue in glaucoma and the unmyelinated nerve head region remains an important site of many early neurodegenerative changes. In both humans and mice, astrocytes constitute the major glial cell type in the region, and in glaucoma they become reactive, influencing the optic nerve head (ONH) microenvironment and disease outcome. Despite recognizing their importance in the progression of the disease, the reactive response of optic nerve head astrocytes remains poorly understood. METHODS To determine the global reactive response of ONH astrocytes in glaucoma we studied their transcriptional response to an elevation in IOP induced by the microbead occlusion model. To specifically isolate astrocyte mRNA in vivo from complex tissues, we used the ribotag method to genetically tag ribosomes in astrocytes, restricting analysis to astrocytes and enabling purification of astrocyte-associated mRNA throughout the entire cell, including the fine processes, for bulk RNA-sequencing. We also assessed the response of astrocytes in the more distal myelinated optic nerve proper (ONP) as glaucomatous changes manifest differently between the two regions. RESULTS Astrocytes of the optic nerve exhibited a region-specific and temporally distinct response. Surprisingly, ONH astrocytes showed very few early transcriptional changes and ONP astrocytes demonstrated substantially larger changes over the course of the experimental period. Energy metabolism, particularly oxidative phosphorylation and mitochondrial protein translation emerged as highly upregulated processes in both ONH and ONP astrocytes, with the former showing additional upregulation in antioxidative capacity and proteolysis. Interestingly, optic nerve astrocytes demonstrated a limited neuroinflammatory response, even when challenged with a more severe elevation in IOP. Lastly, there were a greater number of downregulated processes in both astrocyte populations compared to upregulated processes. CONCLUSION Our findings demonstrate an essential role for energy metabolism in the response of optic nerve astrocytes to elevated IOP, and contrary to expectations, neuroinflammation had a limited overall role. The transcriptional response profile is supportive of the notion that optic nerve astrocytes have a beneficial role in glaucoma. These previously uncharacterized transcriptional response of optic nerve astrocytes to injury reveal their functional diversity and a greater heterogeneity than previously appreciated.
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Affiliation(s)
- Arpan G Mazumder
- Department of Ophthalmology, Schepens Eye Research Institute of Massachusetts Eye and Ear, Harvard Medical School, Boston, MA, 02114, USA
| | - Amélie M Julé
- Department of Biostatistics, Harvard T.H. Chan School of Public Health, Boston, MA, 02115, USA
| | - Daniel Sun
- Department of Ophthalmology, Schepens Eye Research Institute of Massachusetts Eye and Ear, Harvard Medical School, Boston, MA, 02114, USA.
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14
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Keuthan CJ, Schaub JA, Wei M, Fang W, Quillen S, Kimball E, Johnson TV, Ji H, Zack DJ, Quigley HA. Regional Gene Expression in the Retina, Optic Nerve Head, and Optic Nerve of Mice with Optic Nerve Crush and Experimental Glaucoma. Int J Mol Sci 2023; 24:13719. [PMID: 37762022 PMCID: PMC10531004 DOI: 10.3390/ijms241813719] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Revised: 08/28/2023] [Accepted: 08/29/2023] [Indexed: 09/29/2023] Open
Abstract
A major risk factor for glaucomatous optic neuropathy is the level of intraocular pressure (IOP), which can lead to retinal ganglion cell axon injury and cell death. The optic nerve has a rostral unmyelinated portion at the optic nerve head followed by a caudal myelinated region. The unmyelinated region is differentially susceptible to IOP-induced damage in rodent models and human glaucoma. While several studies have analyzed gene expression changes in the mouse optic nerve following optic nerve injury, few were designed to consider the regional gene expression differences that exist between these distinct areas. We performed bulk RNA-sequencing on the retina and separately micro-dissected unmyelinated and myelinated optic nerve regions from naïve C57BL/6 mice, mice after optic nerve crush, and mice with microbead-induced experimental glaucoma (total = 36). Gene expression patterns in the naïve unmyelinated optic nerve showed significant enrichment of the Wnt, Hippo, PI3K-Akt, and transforming growth factor β pathways, as well as extracellular matrix-receptor and cell membrane signaling pathways, compared to the myelinated optic nerve and retina. Gene expression changes induced by both injuries were more extensive in the myelinated optic nerve than the unmyelinated region, and greater after nerve crush than glaucoma. Changes present three and fourteen days after injury largely subsided by six weeks. Gene markers of reactive astrocytes did not consistently differ between injury states. Overall, the transcriptomic phenotype of the mouse unmyelinated optic nerve was significantly different from immediately adjacent tissues, likely dominated by expression in astrocytes, whose junctional complexes are inherently important in responding to IOP elevation.
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Affiliation(s)
- Casey J. Keuthan
- Department of Ophthalmology, Wilmer Eye Institute, School of Medicine, Johns Hopkins University, Baltimore, MD 21287, USA; (C.J.K.)
| | - Julie A. Schaub
- Department of Ophthalmology, Wilmer Eye Institute, School of Medicine, Johns Hopkins University, Baltimore, MD 21287, USA; (C.J.K.)
| | - Meihan Wei
- Department of Biostatistics, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Weixiang Fang
- Department of Biomedical Engineering, School of Medicine, Johns Hopkins University, Baltimore, MD 21287, USA
| | - Sarah Quillen
- Department of Ophthalmology, Wilmer Eye Institute, School of Medicine, Johns Hopkins University, Baltimore, MD 21287, USA; (C.J.K.)
| | - Elizabeth Kimball
- Department of Ophthalmology, Wilmer Eye Institute, School of Medicine, Johns Hopkins University, Baltimore, MD 21287, USA; (C.J.K.)
| | - Thomas V. Johnson
- Department of Ophthalmology, Wilmer Eye Institute, School of Medicine, Johns Hopkins University, Baltimore, MD 21287, USA; (C.J.K.)
| | - Hongkai Ji
- Department of Biostatistics, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Donald J. Zack
- Department of Ophthalmology, Wilmer Eye Institute, School of Medicine, Johns Hopkins University, Baltimore, MD 21287, USA; (C.J.K.)
- Departments of Neuroscience, Molecular Biology and Genetics, and Genetic Medicine, School of Medicine, Johns Hopkins University, Baltimore, MD 21287, USA
| | - Harry A. Quigley
- Department of Ophthalmology, Wilmer Eye Institute, School of Medicine, Johns Hopkins University, Baltimore, MD 21287, USA; (C.J.K.)
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15
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Geiduschek EK, McDowell CM. The Fibro-Inflammatory Response in the Glaucomatous Optic Nerve Head. Int J Mol Sci 2023; 24:13240. [PMID: 37686046 PMCID: PMC10487997 DOI: 10.3390/ijms241713240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Revised: 08/24/2023] [Accepted: 08/25/2023] [Indexed: 09/10/2023] Open
Abstract
Glaucoma is a progressive disease and the leading cause of irreversible blindness. The limited therapeutics available are only able to manage the common risk factor of glaucoma, elevated intraocular pressure (IOP), indicating a great need for understanding the cellular mechanisms behind optic nerve head (ONH) damage during disease progression. Here we review the known inflammatory and fibrotic changes occurring in the ONH. In addition, we describe a novel mechanism of toll-like receptor 4 (TLR4) and transforming growth factor beta-2 (TGFβ2) signaling crosstalk in the cells of the ONH that contribute to glaucomatous damage. Understanding molecular signaling within and between the cells of the ONH can help identify new drug targets and therapeutics.
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Affiliation(s)
| | - Colleen M. McDowell
- Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison, Madison, WI 53705, USA
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16
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Zhu Y, Wang R, Pappas AC, Seifert P, Savol A, Sadreyev RI, Sun D, Jakobs TC. Astrocytes in the Optic Nerve Are Heterogeneous in Their Reactivity to Glaucomatous Injury. Cells 2023; 12:2131. [PMID: 37681863 PMCID: PMC10486930 DOI: 10.3390/cells12172131] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 07/14/2023] [Accepted: 08/18/2023] [Indexed: 09/09/2023] Open
Abstract
The optic nerve head is thought to be the site of initial injury to retinal ganglion cell injury in glaucoma. In the initial segment of the optic nerve directly behind the globe, the ganglion cell axons are unmyelinated and come into direct contact to astrocytes, suggesting that astrocytes may play a role in the pathology of glaucoma. As in other parts of the CNS, optic nerve head astrocytes respond to injury by characteristic changes in cell morphology and gene expression profile. Using RNA-sequencing of glaucomatous optic nerve heads, single-cell PCR, and an in-vivo assay, we demonstrate that an up-regulation of astrocytic phagocytosis is an early event after the onset of increased intraocular pressure. We also show that astrocytes in the glial lamina of the optic nerve are apparently functionally heterogeneous. At any time, even in naïve nerves, some of the cells show signs of reactivity-process hypertrophy, high phagocytic activity, and expression of genetic markers of reactivity whereas neighboring cells apparently are inactive. A period of increased intraocular pressure moves more astrocytes towards the reactive phenotype; however, some cells remain unreactive even in glaucomatous nerves.
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Affiliation(s)
- Ying Zhu
- Department of Ophthalmology, Massachusetts Eye and Ear Infirmary/Schepens Eye Research Institute, Harvard Medical School, 20 Staniford Street, Boston, MA 02114, USA
- Department of Ophthalmology, Stanford University, 1651 Page Mill Road, Palo Alto, CA 94304, USA
| | - Rui Wang
- Department of Ophthalmology, Massachusetts Eye and Ear Infirmary/Schepens Eye Research Institute, Harvard Medical School, 20 Staniford Street, Boston, MA 02114, USA
- Department of Ophthalmology, The First Affiliated Hospital of Northwest University, Xi’an 710002, China
| | - Anthony C. Pappas
- Department of Ophthalmology, Massachusetts Eye and Ear Infirmary/Schepens Eye Research Institute, Harvard Medical School, 20 Staniford Street, Boston, MA 02114, USA
| | - Philip Seifert
- Department of Ophthalmology, Massachusetts Eye and Ear Infirmary/Schepens Eye Research Institute, Harvard Medical School, 20 Staniford Street, Boston, MA 02114, USA
| | - Andrej Savol
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA
- Department of Pathology, Massachusetts General Hospital and Harvard Medical School, 185 Cambridge St., Boston, MA 02114, USA
| | - Ruslan I. Sadreyev
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA
- Department of Pathology, Massachusetts General Hospital and Harvard Medical School, 185 Cambridge St., Boston, MA 02114, USA
| | - Daniel Sun
- Department of Ophthalmology, Massachusetts Eye and Ear Infirmary/Schepens Eye Research Institute, Harvard Medical School, 20 Staniford Street, Boston, MA 02114, USA
| | - Tatjana C. Jakobs
- Department of Ophthalmology, Massachusetts Eye and Ear Infirmary/Schepens Eye Research Institute, Harvard Medical School, 20 Staniford Street, Boston, MA 02114, USA
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17
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Li S, Jakobs TC. Vitamin C protects retinal ganglion cells via SPP1 in glaucoma and after optic nerve damage. Life Sci Alliance 2023; 6:e202301976. [PMID: 37160307 PMCID: PMC10172762 DOI: 10.26508/lsa.202301976] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 04/29/2023] [Accepted: 05/01/2023] [Indexed: 05/11/2023] Open
Abstract
Glaucoma is a common neurodegenerative disorder characterized by retinal ganglion cell death, astrocyte reactivity in the optic nerve, and vision loss. Currently, lowering the intraocular pressure (IOP) is the first-line treatment, but adjuvant neuroprotective approaches would be welcome. Vitamin C possesses neuroprotective activities that are thought to be related to its properties as a co-factor of enzymes and its antioxidant effects. Here, we show that vitamin C promotes a neuroprotective phenotype and increases gene expression related to neurotropic factors, phagocytosis, and mitochondrial ATP production. This effect is dependent on the up-regulation of secreted phosphoprotein 1 (SPP1) in reactive astrocytes via the transcription factor E2F1. SPP1+ astrocytes in turn promote retinal ganglion cell survival in a mouse model of glaucoma. In addition, oral administration of vitamin C lowers the IOP in mice. This study identifies an additional neuroprotective pathway for vitamin C and suggests a potential therapeutic role of vitamin C in neurodegenerative diseases such as glaucoma.
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Affiliation(s)
- Song Li
- Department of Ophthalmology, Harvard Medical School, Boston, MA, USA
- Schepens Eye Research Institute, Massachusetts Eye and Ear, Boston, MA, USA
| | - Tatjana C Jakobs
- Department of Ophthalmology, Harvard Medical School, Boston, MA, USA
- Schepens Eye Research Institute, Massachusetts Eye and Ear, Boston, MA, USA
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18
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Cullen PF, Sun D. Astrocytes of the eye and optic nerve: heterogeneous populations with unique functions mediate axonal resilience and vulnerability to glaucoma. FRONTIERS IN OPHTHALMOLOGY 2023; 3:1217137. [PMID: 37829657 PMCID: PMC10569075 DOI: 10.3389/fopht.2023.1217137] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/14/2023]
Abstract
The role of glia, particularly astrocytes, in mediating the central nervous system's response to injury and neurodegenerative disease is an increasingly well studied topic. These cells perform myriad support functions under physiological conditions but undergo behavioral changes - collectively referred to as 'reactivity' - in response to the disruption of neuronal homeostasis from insults, including glaucoma. However, much remains unknown about how reactivity alters disease progression - both beneficially and detrimentally - and whether these changes can be therapeutically modulated to improve outcomes. Historically, the heterogeneity of astrocyte behavior has been insufficiently addressed under both physiological and pathological conditions, resulting in a fragmented and often contradictory understanding of their contributions to health and disease. Thanks to increased focus in recent years, we now know this heterogeneity encompasses both intrinsic variation in physiological function and insult-specific changes that vary between pathologies. Although previous studies demonstrate astrocytic alterations in glaucoma, both in human disease and animal models, generally these findings do not conclusively link astrocytes to causative roles in neuroprotection or degeneration, rather than a subsequent response. Efforts to bolster our understanding by drawing on knowledge of brain astrocytes has been constrained by the primacy in the literature of findings from peri-synaptic 'gray matter' astrocytes, whereas much early degeneration in glaucoma occurs in axonal regions populated by fibrous 'white matter' astrocytes. However, by focusing on findings from astrocytes of the anterior visual pathway - those of the retina, unmyelinated optic nerve head, and myelinated optic nerve regions - we aim to highlight aspects of their behavior that may contribute to axonal vulnerability and glaucoma progression, including roles in mitochondrial turnover and energy provisioning. Furthermore, we posit that astrocytes of the retina, optic nerve head and myelinated optic nerve, although sharing developmental origins and linked by a network of gap junctions, may be best understood as distinct populations residing in markedly different niches with accompanying functional specializations. A closer investigation of their behavioral repertoires may elucidate not only their role in glaucoma, but also mechanisms to induce protective behaviors that can impede the progressive axonal damage and retinal ganglion cell death that drive vision loss in this devastating condition.
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Affiliation(s)
- Paul F. Cullen
- Department of Ophthalmology, Schepens Eye Research Institute of Massachusetts Eye and Ear, Harvard Medical School, Boston, MA, United States
| | - Daniel Sun
- Department of Ophthalmology, Schepens Eye Research Institute of Massachusetts Eye and Ear, Harvard Medical School, Boston, MA, United States
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19
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Hong Y, Wang Y, Cui Y, Pan J, Mao S, Zhu Y, Wen T, Qi T, Wang A, Luo Y. MicroRNA-124-3p Attenuated Retinal Neovascularization in Oxygen-Induced Retinopathy Mice by Inhibiting the Dysfunction of Retinal Neuroglial Cells through STAT3 Pathway. Int J Mol Sci 2023; 24:11767. [PMID: 37511525 PMCID: PMC10380620 DOI: 10.3390/ijms241411767] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Revised: 07/12/2023] [Accepted: 07/20/2023] [Indexed: 07/30/2023] Open
Abstract
MicroRNA (miRNA) is a non-coding RNA that can regulate the expression of many target genes, and it is widely involved in various important physiological activities. MiR-124-3p was found to associate with the normal development of retinal vessels in our previous study, but the mechanism of its anti-angiogenic effect on pathological retinal neovascularization still needed to be explored. Therefore, this study aimed to investigate the effect and mechanism of miR-124-3p on retinal neovascularization in mice with oxygen-induced retinopathy (OIR). Here, we found that intravitreal injection of miR-124-3p agomir attenuated pathological retinal neovascularization in OIR mice. Moreover, miR-124-3p preserved the astrocytic template, inhibited reactive gliosis, and reduced the inflammatory response as well as necroptosis. Furthermore, miR-124-3p inhibited the signal transducer and activator of transcription 3 (STAT3) pathway and decreased the expression of hypoxia-inducible factor-1α and vascular endothelial growth factor. Taken together, our results revealed that miR-124-3p inhibited retinal neovascularization and neuroglial dysfunction by targeting STAT3 in OIR mice.
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Affiliation(s)
- Yiwen Hong
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou 510060, China
| | - Yishen Wang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou 510060, China
| | - Yamei Cui
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou 510060, China
| | - Jianying Pan
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou 510060, China
| | - Shudi Mao
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou 510060, China
| | - Yanjie Zhu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou 510060, China
| | - Tao Wen
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou 510060, China
| | - Tianyuan Qi
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou 510060, China
| | - Aoxiang Wang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou 510060, China
| | - Yan Luo
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou 510060, China
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20
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Vrapciu AD, Rusu MC, Jianu AM, Motoc AGM, Nicolescu MI. Astrocytes - friends or foes in neurodegenerative disorders. ROMANIAN JOURNAL OF MORPHOLOGY AND EMBRYOLOGY = REVUE ROUMAINE DE MORPHOLOGIE ET EMBRYOLOGIE 2023; 64:305-309. [PMID: 37867348 PMCID: PMC10720932 DOI: 10.47162/rjme.64.3.02] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2023] [Accepted: 08/25/2023] [Indexed: 10/24/2023]
Abstract
Astrocytes (AS) are the most abundant glial cells in the central nervous system (CNS). They have various morphologies and numerous (50-60) branching prolongations, with roles in the maintenance of the CNS function and homeostasis. AS in the optic nerve head (ONH) have specific distribution and function and are involved in the pathogenesis of glaucoma and other neural diseases, modify their morphologies, location, immune phenotype, and ultrastructure, thus being the key players in the active remodeling processes of the ONH.
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Affiliation(s)
- Alexandra Diana Vrapciu
- Discipline of Anatomy, Faculty of Dentistry, Carol Davila University of Medicine and Pharmacy, Bucharest, Romania;
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21
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Keuthan CJ, Schaub J, Wei M, Fang W, Quillen S, Kimball E, Johnson TV, Ji H, Zack DJ, Quigley HA. Regional Gene Expression in the Retina, Optic Nerve Head, and Optic Nerve of Mice with Experimental Glaucoma and Optic Nerve Crush. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.21.529410. [PMID: 36993314 PMCID: PMC10054954 DOI: 10.1101/2023.02.21.529410] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
A major risk factor for glaucomatous optic neuropathy is the level of intraocular pressure (IOP), which can lead to retinal ganglion cell axon injury and cell death. The optic nerve has a rostral unmyelinated portion at the optic nerve head followed by a caudal myelinated region. The unmyelinated region is differentially susceptible to IOP-induced damage in rodent models and in human glaucoma. While several studies have analyzed gene expression changes in the mouse optic nerve following optic nerve injury, few were designed to consider the regional gene expression differences that exist between these distinct areas. We performed bulk RNA-sequencing on the retina and on separately micro-dissected unmyelinated and myelinated optic nerve regions from naïve C57BL/6 mice, mice after optic nerve crush, and mice with microbead-induced experimental glaucoma (total = 36). Gene expression patterns in the naïve unmyelinated optic nerve showed significant enrichment of the Wnt, Hippo, PI3K-Akt, and transforming growth factor β pathways, as well as extracellular matrix-receptor and cell membrane signaling pathways, compared to the myelinated optic nerve and retina. Gene expression changes induced by both injuries were more extensive in the myelinated optic nerve than the unmyelinated region, and greater after nerve crush than glaucoma. Changes three and fourteen days after injury largely subsided by six weeks. Gene markers of reactive astrocytes did not consistently differ between injury states. Overall, the transcriptomic phenotype of the mouse unmyelinated optic nerve was significantly different from immediately adjacent tissues, likely dominated by expression in astrocytes, whose junctional complexes are inherently important in responding to IOP elevation.
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Affiliation(s)
- Casey J. Keuthan
- Department of Ophthalmology, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA
| | - Julie Schaub
- Department of Ophthalmology, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA
| | - Meihan Wei
- Department of Biostatistics, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD 21205, USA
| | - Weixiang Fang
- Department of Biostatistics, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD 21205, USA
| | - Sarah Quillen
- Department of Ophthalmology, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA
| | - Elizabeth Kimball
- Department of Ophthalmology, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA
| | - Thomas V. Johnson
- Department of Ophthalmology, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA
| | - Hongkai Ji
- Department of Biostatistics, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD 21205, USA
| | - Donald J. Zack
- Departments of Ophthalmology, Wilmer Eye Institute, Neuroscience, Molecular Biology and Genetics, and Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA
| | - Harry A. Quigley
- Department of Ophthalmology, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA
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22
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Waxman S, Quinn M, Donahue C, Falo LD, Sun D, Jakobs TC, Sigal IA. Individual astrocyte morphology in the collagenous lamina cribrosa revealed by multicolor DiOlistic labeling. Exp Eye Res 2023; 230:109458. [PMID: 36965593 PMCID: PMC10152998 DOI: 10.1016/j.exer.2023.109458] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 03/17/2023] [Accepted: 03/20/2023] [Indexed: 03/27/2023]
Abstract
Astrocytes in the lamina region of the optic nerve head play vital roles in supporting retinal ganglion cell axon health. In glaucoma, these astrocytes are implicated as early responders to stressors, undergoing characteristic changes in cell function as well as cell morphology. Much of what is currently known about individual lamina astrocyte morphology has been learned from rodent models which lack a defining feature of the human optic nerve head, the collagenous lamina cribrosa (LC). Current methods available for evaluation of collagenous LC astrocyte morphology have significant shortcomings. We aimed to evaluate Multicolor DiOlistic labeling (MuDi) as an approach to reveal individual astrocyte morphologies across the collagenous LC. Gold microcarriers were coated with all combinations of three fluorescent cell membrane dyes, DiI, DiD, and DiO, for a total of seven dye combinations. Microcarriers were delivered to 150 μm-thick coronal vibratome slices through the LC of pig, sheep, goat, and monkey eyes via MuDi. Labeled tissues were imaged with confocal and second harmonic generation microscopy to visualize dyed cells and LC collagenous beams, respectively. GFAP labeling of DiOlistically-labeled cells with astrocyte morphologies was used to investigate cell identity. 3D models of astrocytes were created from confocal image stacks for quantification of morphological features. DiOlistic labeling revealed fine details of LC astrocyte morphologies including somas, primary branches, higher-order branches, and end-feet. Labeled cells with astrocyte morphologies were GFAP+. Astrocytes were visible across seven distinct color channels, allowing high labeling density while still distinguishing individual cells from their neighbors. MuDi was capable of revealing tens to hundreds of collagenous LC astrocytes, in situ, with a single application. 3D astrocyte models allowed automated quantification of morphological features including branch number, length, thickness, hierarchy, and straightness as well as Sholl analysis. MuDi labeling provides an opportunity to investigate morphologies of collagenous LC astrocytes, providing both qualitative and quantitative detail, in healthy tissues. This approach may open doors for research of glaucoma, where astrocyte morphological alterations are thought to coincide with key functional changes related to disease progression.
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Affiliation(s)
- Susannah Waxman
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Marissa Quinn
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Cara Donahue
- Department of Dermatology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Louis D Falo
- Department of Dermatology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA; Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA, USA
| | - Daniel Sun
- Department of Ophthalmology, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA, USA
| | - Tatjana C Jakobs
- Department of Ophthalmology, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA, USA
| | - Ian A Sigal
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA, USA; Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA, USA.
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23
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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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24
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Shen B, Yu H, Zhang M, Chen J, Zhang Y, Xu S, Han R, Huang S, Huang P, Zhong Y. Establishment of a minimally invasive distal traumatic optic neuropathy model in mice to investigate cascade reactions of retinal glial cells. FASEB J 2023; 37:e22682. [PMID: 36468758 DOI: 10.1096/fj.202200861r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 10/29/2022] [Accepted: 11/21/2022] [Indexed: 12/12/2022]
Abstract
Traumatic optic neuropathy (TON) is a complication of craniocerebral, orbital and facial injuries, leading to irreversible vision loss. At present, there is no reliable, widely used animal model, although it has been confirmed that TON can cause the loss of retinal ganglion cells (RGC). However, the cascade reaction of retinal glial cells underlying TON is unclear. Therefore, the establishment of an animal model to explore the pathological mechanism of TON would be of great interest to the scientific community. In this study, we propose a novel mouse model utilizing a 3D stereotaxic apparatus combined with a 27G needle to evaluate damage to the optic nerve by micro-CT, anatomy, SD-OCT and F-VEP. Immunofluorescence, western blotting, qPCR experiments were conducted to investigate the loss of RGCs and activation or inactivation of microglia, astrocytes and Müller glial cells in the retina from the first week to the fourth week after modeling. The results showed that this minimally invasive method caused damage to the distal optic nerve and loss of RGC after optic nerve injury. Microglia cells were found to be activated from the first week to the third week; however, they were inactivated at the fourth week; astrocytes were activated at the second week of injury, while Müller glial cells were gradually inactivated following injury. In conclusion, this method can be used as a novel animal model of distal TON, that results in a series of cascade reactions of retinal glial cells, which will provide a basis for future studies aimed at exploring the mechanism of TON and the search for effective treatment methods.
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Affiliation(s)
- Bingqiao Shen
- Department of Ophthalmology, Ruijin Hospital Affiliated Medical School, Shanghai Jiaotong University, Shanghai, China
| | - Huan Yu
- Department of Ophthalmology, Ruijin Hospital Affiliated Medical School, Shanghai Jiaotong University, Shanghai, China
| | - Mingui Zhang
- Department of Ophthalmology, Ruijin Hospital Affiliated Medical School, Shanghai Jiaotong University, Shanghai, China
| | - Junjue Chen
- Department of Ophthalmology, Ruijin Hospital Affiliated Medical School, Shanghai Jiaotong University, Shanghai, China
| | - Yang Zhang
- Department of Ophthalmology, Ruijin Hospital Affiliated Medical School, Shanghai Jiaotong University, Shanghai, China
| | - Shushu Xu
- Department of Ophthalmology, Ruijin Hospital Affiliated Medical School, Shanghai Jiaotong University, Shanghai, China
| | - Ruiqi Han
- Department of Ophthalmology, Ruijin Hospital Affiliated Medical School, Shanghai Jiaotong University, Shanghai, China
| | - Shouyue Huang
- Department of Ophthalmology, Ruijin Hospital Affiliated Medical School, Shanghai Jiaotong University, Shanghai, China
| | - Ping Huang
- Department of Orthopaedics, Shanghai Key Laboratory for Prevention and Treatment of Bone and Joint Diseases, Shanghai Institute of Traumatology and Orthopaedics, Ruijin Hospital Affiliated Medical School, Shanghai Jiaotong University, Shanghai, China
| | - Yisheng Zhong
- Department of Ophthalmology, Ruijin Hospital Affiliated Medical School, Shanghai Jiaotong University, Shanghai, China
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25
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Li S, Jakobs TC. Secreted phosphoprotein 1 slows neurodegeneration and rescues visual function in mouse models of aging and glaucoma. Cell Rep 2022; 41:111880. [PMID: 36577373 PMCID: PMC9847489 DOI: 10.1016/j.celrep.2022.111880] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 11/01/2022] [Accepted: 12/02/2022] [Indexed: 12/29/2022] Open
Abstract
Aging causes an irreversible, cumulative decline in neuronal function. Using the visual system as a model, we show that astrocytes play a critical role in maintaining retinal ganglion cell health and that deletion of SPP1 (secreted phosphoprotein 1, or osteopontin) from astrocytes leads to increased vulnerability of ganglion cells to age, elevated intraocular pressure, and traumatic optic nerve damage. Overexpression of SPP1 slows the age-related decline in ganglion cell numbers and is highly protective of visual function in a mouse model of glaucoma. SPP1 acts by promoting phagocytosis and secretion of neurotrophic factors while inhibiting production of neurotoxic and pro-inflammatory factors. SPP1 up-regulates transcription of genes related to oxidative phosphorylation, functionally enhances mitochondrial respiration, and promotes the integrity of mitochondrial microstructure. SPP1 increases intracellular ATP concentration via up-regulation of VDAC1.
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Affiliation(s)
- Song Li
- Department of Ophthalmology, Harvard Medical School, Boston, MA 02114, USA; Schepens Eye Research Institute, Massachusetts Eye and Ear, Boston, MA 02114, USA.
| | - Tatjana C Jakobs
- Department of Ophthalmology, Harvard Medical School, Boston, MA 02114, USA; Schepens Eye Research Institute, Massachusetts Eye and Ear, Boston, MA 02114, USA.
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26
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Bernstein SL, Guo Y, Mehrabian Z, Miller NR. Neuroprotection and Neuroregeneration Strategies Using the rNAION Model: Theory, Histology, Problems, Results and Analytical Approaches. Int J Mol Sci 2022; 23:ijms232415604. [PMID: 36555246 PMCID: PMC9778957 DOI: 10.3390/ijms232415604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Revised: 10/18/2022] [Accepted: 11/23/2022] [Indexed: 12/13/2022] Open
Abstract
Nonarteritic anterior ischemic optic neuropathy (NAION) is the most common cause of sudden optic nerve (ON)-related vision loss in humans. Study of this disease has been limited by the lack of available tissue and difficulties in evaluating both treatments and the window of effectiveness after symptom onset. The rodent nonarteritic anterior ischemic optic neuropathy model (rNAION) closely resembles clinical NAION in its pathophysiological changes and physiological responses. The rNAION model enables analysis of the specific responses to sudden ischemic axonopathy and effectiveness of potential treatments. However, there are anatomic and genetic differences between human and rodent ON, and the inducing factors for the disease and the model are different. These variables can result in marked differences in lesion development between the two species, as well as in the possible responses to various treatments. These caveats are discussed in the current article, as well as some of the species-associated differences that may be related to ischemic lesion severity and responses.
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Affiliation(s)
- Steven L. Bernstein
- Department of Ophthalmology and Visual Sciences, University of Maryland at Baltimore School of Medicine, 10 S. Pine St., Baltimore, MD 21201, USA
- Department of Anatomy and Neurobiology, University of Maryland at Baltimore School of Medicine, 10 S. Pine St., Baltimore, MD 21201, USA
- Correspondence: ; Tel.: +1-410-706-3712
| | - Yan Guo
- Department of Ophthalmology and Visual Sciences, University of Maryland at Baltimore School of Medicine, 10 S. Pine St., Baltimore, MD 21201, USA
| | - Zara Mehrabian
- Department of Ophthalmology and Visual Sciences, University of Maryland at Baltimore School of Medicine, 10 S. Pine St., Baltimore, MD 21201, USA
| | - Neil R. Miller
- Wilmer Eye Institute, Johns Hopkins University School of Medicine, 600 N. Wolfe St., Baltimore, MD 21205, USA
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27
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Tan Z, Guo Y, Shrestha M, Sun D, Gregory-Ksander M, Jakobs TC. Microglia depletion exacerbates retinal ganglion cell loss in a mouse model of glaucoma. Exp Eye Res 2022; 225:109273. [PMID: 36206859 PMCID: PMC10970711 DOI: 10.1016/j.exer.2022.109273] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 09/09/2022] [Accepted: 09/26/2022] [Indexed: 01/11/2023]
Abstract
To test whether depletion of microglia in the optic nerve head has a beneficial effect on retinal ganglion cell numbers and function, we depleted microglia by oral administration of the CSF1R antagonist PLX5622. Then, ocular hypertension was induced by unilateral injection of magnetic microbeads into the anterior chamber. Visual function was assessed with pattern electroretinography and measurement of the optomotor reflex. Retinal ganglion cell bodies and axons were counted and gene expression patterns in optic nerve head astrocytes were tested on freshly dissociated astrocytes. PLX5622 efficiently depleted microglia in the retina and the optic nerve head, but about 20% of microglia persisted in the myelinated optic nerve proper even after prolonged exposure to the drug. PLX5622 did not affect ganglion cell function by itself. Elevation of the IOP for four weeks led to the expected decrease in visual acuity and pattern ERG amplitude. Microglia ablation did not affect these parameters. Ganglion cell and axon numbers were counted histologically post mortem. Mice in the microglia depletion group showed a moderate but significantly greater loss of ganglion cells than the control group. At four weeks post microbead injection, gene expression patterns in optic nerve head astrocytes are consistent with an A2 (or neuroprotective) pattern. Microglia depletion blunted the up-regulation of A2 genes in astrocytes. In conclusion, microglia depletion is unlikely to protect retinal ganglion cells in early glaucoma.
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Affiliation(s)
- Zizhu Tan
- The First Affiliated Hospital of Xi'an Jiaotong University, 277 Yanta West Road, Xi'an, Shaanxi, 710061, China; Schepens Eye Research Institute/Massachusetts Eye and Ear, Harvard University School of Medicine, 20 Staniford Street, Boston, MA, 02114, USA
| | - Yinjie Guo
- Schepens Eye Research Institute/Massachusetts Eye and Ear, Harvard University School of Medicine, 20 Staniford Street, Boston, MA, 02114, USA; The Second Xiangya Hospital of Central South University, 139 Middle Renmin Road, Changsha, Hunan, 410011, China
| | - Maleeka Shrestha
- Schepens Eye Research Institute/Massachusetts Eye and Ear, Harvard University School of Medicine, 20 Staniford Street, Boston, MA, 02114, USA
| | - Daniel Sun
- Schepens Eye Research Institute/Massachusetts Eye and Ear, Harvard University School of Medicine, 20 Staniford Street, Boston, MA, 02114, USA
| | - Meredith Gregory-Ksander
- Schepens Eye Research Institute/Massachusetts Eye and Ear, Harvard University School of Medicine, 20 Staniford Street, Boston, MA, 02114, USA
| | - Tatjana C Jakobs
- Schepens Eye Research Institute/Massachusetts Eye and Ear, Harvard University School of Medicine, 20 Staniford Street, Boston, MA, 02114, USA.
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28
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Tang Y, Chen Y, Chen D. The heterogeneity of astrocytes in glaucoma. Front Neuroanat 2022; 16:995369. [PMID: 36466782 PMCID: PMC9714578 DOI: 10.3389/fnana.2022.995369] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Accepted: 10/31/2022] [Indexed: 09/10/2023] Open
Abstract
Glaucoma is a leading cause of blindness with progressive degeneration of retinal ganglion cells. Aging and increased intraocular pressure (IOP) are major risk factors. Lowering IOP does not always stop the disease progression. Alternative ways of protecting the optic nerve are intensively studied in glaucoma. Astrocytes are macroglia residing in the retina, optic nerve head (ONH), and visual brain, which keep neuronal homeostasis, regulate neuronal activities and are part of the immune responses to the retina and brain insults. In this brief review, we discuss the activation and heterogeneity of astrocytes in the retina, optic nerve head, and visual brain of glaucoma patients and animal models. We also discuss some recent transgenic and gene knockout studies using glaucoma mouse models to clarify the role of astrocytes in the pathogenesis of glaucoma. Astrocytes are heterogeneous and play crucial roles in the pathogenesis of glaucoma, especially in the process of neuroinflammation and mitochondrial dysfunction. In astrocytes, overexpression of Stat3 or knockdown of IκKβ/p65, caspase-8, and mitochondrial uncoupling proteins (Ucp2) can reduce ganglion cell loss in glaucoma mouse models. Based on these studies, therapeutic strategies targeting the heterogeneity of reactive astrocytes by enhancing their beneficial reactivity or suppressing their detrimental reactivity are alternative options for glaucoma treatment in the future.
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Affiliation(s)
- Yunjing Tang
- Research Laboratory of Ophthalmology and Vision Sciences, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China
- Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu, China
| | - Yongjiang Chen
- The School of Optometry and Vision Science, University of Waterloo, Waterloo, ON, Canada
| | - Danian Chen
- Research Laboratory of Ophthalmology and Vision Sciences, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China
- Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu, China
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29
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Li Y, Wen Y, Liu X, Li Z, Lin B, Deng C, Yu Z, Zhu Y, Zhao L, Su W, Zhuo Y. Single-cell RNA sequencing reveals a landscape and targeted treatment of ferroptosis in retinal ischemia/reperfusion injury. J Neuroinflammation 2022; 19:261. [PMID: 36289494 PMCID: PMC9597965 DOI: 10.1186/s12974-022-02621-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Accepted: 10/09/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The aim of this study was to establish a complete retinal cell atlas of ischemia-reperfusion injury by single-cell RNA sequencing, and to explore the underlying mechanism of retinal ischemia-reperfusion injury in mice. METHODS Single-cell RNA sequencing was used to evaluate changes in the mouse retinal ischemia reperfusion model. In vivo and in vitro experiments were performed to verify the protective effect of inhibiting ferroptosis in retinal ischemia-reperfusion injury. RESULTS After ischemia-reperfusion injury, retinal cells were significantly reduced, accompanied by the activation of myeloid and a large amount of blood-derived immune cell infiltration. The IFNG, MAPK and NFKB signaling pathways in retinal neuronal cells, together with the TNF signaling pathway in myeloid give rise to a strong inflammatory response in the I/R state. Besides, the expression of genes implicating iron metabolism, oxidative stress and multiple programed cell death pathways have changed in cell subtypes described above. Especially the ferroptosis-related genes and blocking this process could apparently alleviate the inflammatory immune responses and enhance retinal ganglion cells survival. CONCLUSIONS We established a comprehensive landscape of mouse retinal ischemia-reperfusion injury at the single-cell level, revealing the important role of ferroptosis during this injury, and targeted inhibition of ferroptosis can effectively protect retinal structure and function.
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Affiliation(s)
- Yangyang Li
- grid.12981.330000 0001 2360 039XState Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, 510060 China
| | - Yuwen Wen
- grid.12981.330000 0001 2360 039XState Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, 510060 China
| | - Xiuxing Liu
- grid.12981.330000 0001 2360 039XState Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, 510060 China
| | - Zhuang Li
- grid.12981.330000 0001 2360 039XState Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, 510060 China
| | - Bingying Lin
- grid.12981.330000 0001 2360 039XState Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, 510060 China
| | - Caibin Deng
- grid.12981.330000 0001 2360 039XState Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, 510060 China
| | - Ziyu Yu
- grid.12981.330000 0001 2360 039XState Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, 510060 China
| | - Yingting Zhu
- grid.12981.330000 0001 2360 039XState Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, 510060 China
| | - Ling Zhao
- grid.12981.330000 0001 2360 039XState Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, 510060 China
| | - Wenru Su
- grid.12981.330000 0001 2360 039XState Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, 510060 China
| | - Yehong Zhuo
- grid.12981.330000 0001 2360 039XState Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, 510060 China
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Chaudhary P, Stowell C, Reynaud J, Gardiner SK, Yang H, Williams G, Williams I, Marsh-Armstrong N, Burgoyne CF. Optic Nerve Head Myelin-Related Protein, GFAP, and Iba1 Alterations in Non-Human Primates With Early to Moderate Experimental Glaucoma. Invest Ophthalmol Vis Sci 2022; 63:9. [PMID: 36239974 PMCID: PMC9586137 DOI: 10.1167/iovs.63.11.9] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Purpose The purpose of this study was to test if optic nerve head (ONH) myelin basic protein (MBP), 2′,3′-cyclic nucleotide 3′-phosphodiesterase (CNPase), glial fibrillary acidic protein (GFAP), and ionized calcium binding adaptor molecule 1 (Iba1) proteins are altered in non-human primate (NHP) early/moderate experimental glaucoma (EG). Methods Following paraformaldehyde perfusion, control and EG eye ONH tissues from four NHPs were paraffin embedded and serially (5 µm) vertically sectioned. Anti-MBP, CNPase, GFAP, Iba1, and nuclear dye-stained sections were imaged using sub-saturating light intensities. Whole-section images were segmented creating anatomically consistent laminar (L) and retrolaminar (RL) regions/sub-regions. EG versus control eye intensity/pixel-cluster density data within L and two RL regions (RL1 [1-250 µm]/RL2 [251-500 µm] from L) were compared using random effects models within the statistical program “R.” Results EG eye retinal nerve fiber loss ranged from 0% to 20%. EG eyes’ MBP and CNPase intensity were decreased within the RL1 (MBP = 31.4%, P < 0.001; CNPase =62.3%, P < 0.001) and RL2 (MBP = 19.6%, P < 0.001; CNPase = 56.1%, P = 0.0004) regions. EG eye GFAP intensity was decreased in the L (41.6%, P < 0.001) and RL regions (26.7% for RL1, and 28.4% for RL2, both P < 0.001). Iba1+ and NucBlue pixel-cluster density were increased in the laminar (28.2%, P = 0.03 and 16.6%, P = 0.008) and both RL regions (RL1 = 37.3%, P = 0.01 and 23.7%, P = 0.0002; RL2 = 53.7%, P = 0.002 and 33.2%, P < 0.001). Conclusions Retrolaminar myelin disruption occurs early in NHP EG and may be accompanied by laminar and retrolaminar decreases in astrocyte process labeling and increases in microglial/ macrophage density. The mechanistic and therapeutic implications of these findings warrant further study.
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Affiliation(s)
- Priya Chaudhary
- Optic Nerve Head Research Laboratory, Devers Eye Institute, Legacy Research Institute, Portland, Oregon, United States.,Discoveries in Sight, Devers Eye Institute, Legacy Research Institute, Portland, Oregon, United States
| | - Cheri Stowell
- Optic Nerve Head Research Laboratory, Devers Eye Institute, Legacy Research Institute, Portland, Oregon, United States.,Discoveries in Sight, Devers Eye Institute, Legacy Research Institute, Portland, Oregon, United States
| | - Juan Reynaud
- Optic Nerve Head Research Laboratory, Devers Eye Institute, Legacy Research Institute, Portland, Oregon, United States.,Discoveries in Sight, Devers Eye Institute, Legacy Research Institute, Portland, Oregon, United States
| | - Stuart K Gardiner
- Discoveries in Sight, Devers Eye Institute, Legacy Research Institute, Portland, Oregon, United States
| | - Hongli Yang
- Optic Nerve Head Research Laboratory, Devers Eye Institute, Legacy Research Institute, Portland, Oregon, United States.,Discoveries in Sight, Devers Eye Institute, Legacy Research Institute, Portland, Oregon, United States
| | - Galen Williams
- Optic Nerve Head Research Laboratory, Devers Eye Institute, Legacy Research Institute, Portland, Oregon, United States.,Discoveries in Sight, Devers Eye Institute, Legacy Research Institute, Portland, Oregon, United States
| | - Imee Williams
- Optic Nerve Head Research Laboratory, Devers Eye Institute, Legacy Research Institute, Portland, Oregon, United States.,Discoveries in Sight, Devers Eye Institute, Legacy Research Institute, Portland, Oregon, United States
| | | | - Claude F Burgoyne
- Optic Nerve Head Research Laboratory, Devers Eye Institute, Legacy Research Institute, Portland, Oregon, United States.,Discoveries in Sight, Devers Eye Institute, Legacy Research Institute, Portland, Oregon, United States
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Li Z, Peng F, Liu Z, Li S, Li L, Qian X. Mechanobiological responses of astrocytes in optic nerve head due to biaxial stretch. BMC Ophthalmol 2022; 22:368. [PMID: 36114477 PMCID: PMC9482189 DOI: 10.1186/s12886-022-02592-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Accepted: 09/06/2022] [Indexed: 11/25/2022] Open
Abstract
Background Elevated intraocular pressure (IOP) is the main risk factor for glaucoma, which might cause the activation of astrocytes in optic nerve head. To determine the effect of mechanical stretch on the astrocytes, we investigated the changes in cell phenotype, proteins of interest and signaling pathways under biaxial stretch. Method The cultured astrocytes in rat optic nerve head were stretched biaxially by 10 and 17% for 24 h, respectively. Then, we detected the morphology, proliferation and apoptosis of the stretched cells, and performed proteomics analysis. Protein expression was analyzed by Isobaric tags for relative and absolute quantification (iTRAQ) mass spectrometry. Proteins of interest and signaling pathways were screened using Gene Ontology enrichment analysis and pathway enrichment analysis, and the results were verified by western blot and the gene-chip data from Gene Expression Omnibus (GEO) database. Result The results showed that rearrangement of the actin cytoskeleton in response to stimulation by mechanical stress and proliferation rate of astrocytes decreased under 10 and 17% stretch condition, while there was no significant difference on the apoptosis rate of astrocytes in both groups. In the iTRAQ quantitative experiment, there were 141 differential proteins in the 10% stretch group and 140 differential proteins in the 17% stretch group. These proteins include low-density lipoprotein receptor-related protein (LRP6), caspase recruitment domain family, member 10 (CARD10), thrombospondin 1 (THBS1) and tetraspanin (CD81). The western blot results of LRP6, THBS1 and CD81 were consistent with that of iTRAQ experiment. ANTXR2 and CARD10 were both differentially expressed in the mass spectrometry results and GEO database. We also screened out the signaling pathways associated with astrocyte activation, including Wnt/β–catenin pathway, NF-κB signaling pathway, PI3K-Akt signaling pathway, MAPK signaling pathway, Jak-STAT signaling pathway, ECM-receptor interaction, and transforming growth factor-β (TGF-β) signaling pathway. Conclusion Mechanical stimulation can induce changes in cell phenotype, some proteins and signaling pathways, which might be associated with astrocyte activation. These proteins and signaling pathways may help us have a better understanding on the activation of astrocytes and the role astrocyte activation played in glaucomatous optic neuropathy. Supplementary Information The online version contains supplementary material available at 10.1186/s12886-022-02592-8.
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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] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 07/11/2022] [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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Histological and molecular characterization of glaucoma model induced by one or two injections of microbeads to the anterior chamber of mice. Int Ophthalmol 2022; 42:3763-3775. [PMID: 35731354 DOI: 10.1007/s10792-022-02372-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Accepted: 05/28/2022] [Indexed: 10/17/2022]
Abstract
PURPOSE To characterize glaucoma-induced damage following injections of plastic microbeads into the anterior chamber of mice. METHODS Mice were divided into three groups: a single plastic microbeads injection (n = 21); two consecutive plastic microbead injections to the right eye at 1-week intervals, 4 of which with two consecutive saline injections in the left eye (n = 15); and an additional control group of two consecutive saline injections at 1-week intervals (n = 6). Intraocular pressure (IOP) was measured weekly. Retinal thickness, ganglion cells (RGCs) and axonal loss, inflammatory and gliosis reactions were measured at week four. Molecular analysis using qRT-PCR in the microbeads injection groups focused on expression levels of inflammation and glaucoma-related genes. RESULTS Mean IOP following single injection at 4 weeks was significantly elevated compared to baseline in injected eyes (14.5 ± 3.3 mmHg vs. 11.1 ± 2.5 mmHg, respectively, p = 0.003) and not in fellow eyes (13.2 ± 2.9 mmHg vs. 12.2 ± 2.9, respectively, NS). Six (35.3%) bead-injected eyes had IOP ≥ 17 mmHg compared with 2 (11.8%) saline-injected control eyes. Retinal thickness in injected and fellow eyes was 193.7 ± 15.5 µm and 223.9 ± 15.5 µm, respectively (p = 0.03). RGC loss in injected and fellow eyes was 16.0 ± 0.5 and 17.6 ± 0.7 cells per 200 µm, respectively (p = 0.005). Retinal gliosis, axonal loss and inflammatory cell infiltration to the bead-injected eyes were noted. Molecular analysis following double injection showed STAT3 expression decreased in the glaucoma-induced optic nerves (0.69 ± 0.3 vs. 1.16 ± 0.3, p = 0.04), but increased in the glaucoma-induced retinae (p = 0.05) versus saline; retinal IL-1β decreased significantly (0.04 ± 0.04 vs. 0.36 ± 0.2, p = 0.02). TNF-α, NFkB and SOD-1 expression did not change. CONCLUSION One/two injections of microbeads elevated IOP, with measurable neuronal damage. An inflammatory response was detected in the injured retina and optic nerve. The therapeutic significance of these findings should be explored.
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Kimball EC, Quillen S, Pease ME, Keuthan C, Nagalingam A, Zack DJ, Johnson TV, Quigley HA. Aquaporin 4 is not present in normal porcine and human lamina cribrosa. PLoS One 2022; 17:e0268541. [PMID: 35709078 PMCID: PMC9202842 DOI: 10.1371/journal.pone.0268541] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Accepted: 05/03/2022] [Indexed: 02/02/2023] Open
Abstract
Aquaporin 4 is absent from astrocytes in the rodent optic nerve head, despite high expression in the retina and myelinated optic nerve. The purpose of this study was to quantify regional aquaporin channel expression in astrocytes of the porcine and human mouse optic nerve (ON). Ocular tissue sections were immunolabeled for aquaporins 1(AQP1), 4(AQP4), and 9(AQP9), myelin basic protein (MBP), glial fibrillary acidic protein (GFAP) and alpha-dystroglycan (αDG) for their presence in retina, lamina, myelin transition zone (MTZ, region just posterior to lamina) and myelinated ON (MON). Semi- quantification of AQP4 labeling & real-time quantitative PCR (qPCR) data were analyzed in retina and ON tissue. Porcine and control human eyes had abundant AQP4 in Müller cells, retinal astrocytes, and myelinated ON (MON), but minimal expression in the lamina cribrosa. AQP1 and AQP9 were present in retina, but not in the lamina. Immunolabeling of GFAP and αDG was similar in lamina, myelin transition zone (MTZ) and MON regions. Semi-quantitative AQP4 labeling was at background level in lamina, increasing in the MTZ, and highest in the MON (lamina vs MTZ, MON; p≤0.05, p≤0.01, respectively). Expression of AQP4 mRNA was minimal in lamina and substantial in MTZ and MON, while GFAP mRNA expression was uniform among the lamina, MTZ, and MON regions. Western blot assay showed AQP4 protein expression in the MON samples, but none was detected in the lamina tissue. The minimal presence of AQP4 in the lamina is a specific regional phenotype of astrocytes in the mammalian optic nerve head.
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Affiliation(s)
- Elizabeth C. Kimball
- Glaucoma Center of Excellence, Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Sarah Quillen
- Glaucoma Center of Excellence, Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Mary E. Pease
- Glaucoma Center of Excellence, Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Casey Keuthan
- Glaucoma Center of Excellence, Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Aru Nagalingam
- Glaucoma Center of Excellence, Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Donald J. Zack
- Glaucoma Center of Excellence, Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Thomas V. Johnson
- Glaucoma Center of Excellence, Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Harry A. Quigley
- Glaucoma Center of Excellence, Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland, United States of America
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Lin C, Toychiev A, Ablordeppey R, Slavi N, Srinivas M, Benavente-Perez A. Myopia Alters the Structural Organization of the Retinal Vasculature, GFAP-Positive Glia, and Ganglion Cell Layer Thickness. Int J Mol Sci 2022; 23:6202. [PMID: 35682880 PMCID: PMC9181442 DOI: 10.3390/ijms23116202] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 05/22/2022] [Accepted: 05/30/2022] [Indexed: 11/17/2022] Open
Abstract
To describe the effect of myopic eye growth on the structure and distribution of astrocytes, vasculature, and retinal nerve fiber layer thickness, which are critical for inner retinal tissue homeostasis and survival. Astrocyte and capillary distribution, retinal nerve fiber (RNFL), and ganglion cell layer (GCL) thicknesses were assessed using immunochemistry and spectral domain optical coherence tomography on eleven retinas of juvenile common marmosets (Callithrix Jacchus), six of which were induced with lens-induced myopia (refraction, Rx: -7.01 ± 1.8D). Five untreated age-matched juvenile marmoset retinas were used as controls (Rx: -0.74 ± 0.4D). Untreated marmoset eyes grew normally, their RNFL thickened and their astrocyte numbers were associated with RNFL thickness. Marmosets with induced myopia did not show this trend and, on the contrary, had reduced astrocyte numbers, increased GFAP-immunopositive staining, thinner RNFL, lower peripheral capillary branching, and increased numbers of string vessels. The myopic changes in retinal astrocytes, vasculature, and retinal nerve fiber layer thickness suggest a reorganization of the astrocyte and vascular templates during myopia development and progression. Whether these adaptations are beneficial or harmful to the retina remains to be investigated.
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Affiliation(s)
| | | | | | | | | | - Alexandra Benavente-Perez
- Department of Biological Sciences, SUNY College of Optometry, New York, NY 10036, USA; (C.L.); (A.T.); (R.A.); (N.S.); (M.S.)
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Strat AN, Kirschner A, Yoo H, Singh A, Bagué T, Li H, Herberg S, Ganapathy PS. Engineering a 3D hydrogel system to study optic nerve head astrocyte morphology and behavior. Exp Eye Res 2022; 220:109102. [PMID: 35525298 DOI: 10.1016/j.exer.2022.109102] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Revised: 04/21/2022] [Accepted: 04/28/2022] [Indexed: 11/19/2022]
Affiliation(s)
- Ana N Strat
- Department of Ophthalmology & Visual Sciences, SUNY Upstate Medical University, Syracuse, NY, 13210, USA; Department of Neuroscience and Physiology, SUNY Upstate Medical University, Syracuse, NY, 13210, USA; BioInspired Institute, Syracuse University, Syracuse, NY, 13244, USA
| | - Alexander Kirschner
- Department of Ophthalmology & Visual Sciences, SUNY Upstate Medical University, Syracuse, NY, 13210, USA
| | - Hannah Yoo
- Department of Ophthalmology & Visual Sciences, SUNY Upstate Medical University, Syracuse, NY, 13210, USA
| | - Ayushi Singh
- Department of Ophthalmology & Visual Sciences, SUNY Upstate Medical University, Syracuse, NY, 13210, USA; BioInspired Institute, Syracuse University, Syracuse, NY, 13244, USA; Department of Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, NY, 13210, USA
| | - Tyler Bagué
- Department of Ophthalmology & Visual Sciences, SUNY Upstate Medical University, Syracuse, NY, 13210, USA
| | - Haiyan Li
- Department of Ophthalmology & Visual Sciences, SUNY Upstate Medical University, Syracuse, NY, 13210, USA; BioInspired Institute, Syracuse University, Syracuse, NY, 13244, USA; Department of Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, NY, 13210, USA
| | - Samuel Herberg
- Department of Ophthalmology & Visual Sciences, SUNY Upstate Medical University, Syracuse, NY, 13210, USA; BioInspired Institute, Syracuse University, Syracuse, NY, 13244, USA; Department of Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, NY, 13210, USA; Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY, 13210, USA; Department of Biomedical and Chemical Engineering, Syracuse University, Syracuse, NY, 13244, USA
| | - Preethi S Ganapathy
- Department of Ophthalmology & Visual Sciences, SUNY Upstate Medical University, Syracuse, NY, 13210, USA; Department of Neuroscience and Physiology, SUNY Upstate Medical University, Syracuse, NY, 13210, USA; BioInspired Institute, Syracuse University, Syracuse, NY, 13244, USA.
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Dillinger AE, Weber GR, Mayer M, Schneider M, Göppner C, Ohlmann A, Shamonin M, Monkman GJ, Fuchshofer R. CCN2/CTGF—A Modulator of the Optic Nerve Head Astrocyte. Front Cell Dev Biol 2022; 10:864433. [PMID: 35493079 PMCID: PMC9047870 DOI: 10.3389/fcell.2022.864433] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Accepted: 03/18/2022] [Indexed: 12/14/2022] Open
Abstract
In primary open-angle glaucoma (POAG), a neurodegenerative disease of the optic nerve (ON) and leading cause of blindness, the optic nerve head (ONH) undergoes marked structural extracellular matrix (ECM) changes, which contribute to its permanent deformation and to degeneration of ON axons. The remodeling process of the ECM causes changes in the biomechanical properties of the ONH and the peripapillary sclera, which is accompanied by an increased reactivity of the resident astrocytes. The molecular factors involved in the remodeling process belong to the Transforming growth factor (TGF)-β superfamily, especially TGF-β2. In previous publications we showed that TGF-β2 induced ECM alterations are mediated by Cellular Communication Network Factor (CCN)2/Connective Tissue Growth Factor (CTGF) and recently we showed that CCN2/CTGF is expressed by astrocytes of the ON under normal conditions. In this study we wanted to get a better understanding of the function of CCN2/CTGF under normal and pathologic conditions. To this end, we analyzed the glial lamina and peripapillary sclera of CCN2/CTGF overexpressing mice and studied the effect of CCN2/CTGF and increasing substratum stiffness on murine ON astrocytes in vitro. We observed enhanced astrocyte reactivity in the ONH, increased ECM protein synthesis in the peripapillary sclera and increased Ccn2/Ctgf expression in the ONH during the pathologic development in situ. CCN2/CTGF treatment of primary murine ON astrocytes induced a higher migration rate, and increase of ECM proteins including fibronectin, elastin and collagen type III. Furthermore, the astrocytes responded to stiffer substratum with increased glial fibrillary acidic protein, vimentin, actin and CCN2/CTGF synthesis. Finally, we observed the reinforced appearance of CCN2/CTGF in the lamina cribrosa of glaucomatous patients. We conclude that reactive changes in ONH astrocytes, induced by the altered biomechanical characteristics of the region, give rise to a self-amplifying process that includes increased TGF-β2/CCN2/CTGF signaling and leads to the synthesis of ECM molecules and cytoskeleton proteins, a process that in turn augments the stiffness at the ONH. Such a scenario may finally result in a vicious circle in the pathogenesis of POAG. The transgenic CTGF-overexpressing mouse model might be an optimal model to study the chronic pathological POAG changes in the ONH.
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Affiliation(s)
- Andrea E. Dillinger
- Institute of Human Anatomy and Embryology, University of Regensburg, Regensburg, Germany
| | - Gregor R. Weber
- Institute of Human Anatomy and Embryology, University of Regensburg, Regensburg, Germany
| | - Matthias Mayer
- Faculty of Electrical Engineering and Information Technology, Ostbayerische Technische Hochschule Regensburg, Regensburg, Germany
| | - Magdalena Schneider
- Institute of Human Anatomy and Embryology, University of Regensburg, Regensburg, Germany
| | - Corinna Göppner
- Institute of Human Anatomy and Embryology, University of Regensburg, Regensburg, Germany
| | - Andreas Ohlmann
- Department of Ophthalmology, University Hospital, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Mikhail Shamonin
- Faculty of Electrical Engineering and Information Technology, Ostbayerische Technische Hochschule Regensburg, Regensburg, Germany
| | - Gareth J. Monkman
- Faculty of Electrical Engineering and Information Technology, Ostbayerische Technische Hochschule Regensburg, Regensburg, Germany
| | - Rudolf Fuchshofer
- Institute of Human Anatomy and Embryology, University of Regensburg, Regensburg, Germany
- *Correspondence: Rudolf Fuchshofer,
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Molecular regulation of neuroinflammation in glaucoma: Current knowledge and the ongoing search for new treatment targets. Prog Retin Eye Res 2022; 87:100998. [PMID: 34348167 PMCID: PMC8803988 DOI: 10.1016/j.preteyeres.2021.100998] [Citation(s) in RCA: 57] [Impact Index Per Article: 28.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Revised: 07/23/2021] [Accepted: 07/26/2021] [Indexed: 12/11/2022]
Abstract
Neuroinflammation relying on the inflammatory responses of glial cells has emerged as an impactful component of the multifactorial etiology of neurodegeneration in glaucoma. It has become increasingly evident that despite early adaptive and reparative features of glial responses, prolonged reactivity of the resident glia, along with the peripheral immune cells, create widespread toxicity to retinal ganglion cell (RGC) axons, somas, and synapses. As much as the synchronized responses of astrocytes and microglia to glaucoma-related stress or neuron injury, their bi-directional interactions are critical to build and amplify neuroinflammation and to dictate the neurodegenerative outcome. Although distinct molecular programs regulate somatic and axonal degeneration in glaucoma, inhibition of neurodegenerative inflammation can provide a broadly beneficial treatment strategy to rescue RGC integrity and function. Since inflammatory toxicity and mitochondrial dysfunction are converging etiological paths that can boost each other and feed into a vicious cycle, anti-inflammatory treatments may also offer a multi-target potential. This review presents an overview of the current knowledge on neuroinflammation in glaucoma with particular emphasis on the cell-intrinsic and cell-extrinsic factors involved in the reciprocal regulation of glial responses, the interdependence between inflammatory and mitochondrial routes of neurodegeneration, and the research aspects inspiring for prospective immunomodulatory treatments. With the advent of powerful technologies, ongoing research on molecular and functional characteristics of glial responses is expected to accumulate more comprehensive and complementary information and to rapidly move the field forward to safe and effective modulation of the glial pro-inflammatory activities, while restoring or augmenting the glial immune-regulatory and neurosupport functions.
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Zhao J, Gonsalvez GB, Mysona BA, Smith SB, Bollinger KE. Sigma 1 Receptor Contributes to Astrocyte-Mediated Retinal Ganglion Cell Protection. Invest Ophthalmol Vis Sci 2022; 63:1. [PMID: 35103752 PMCID: PMC8819349 DOI: 10.1167/iovs.63.2.1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Accepted: 12/28/2021] [Indexed: 01/22/2023] Open
Abstract
Purpose Sigma 1 receptor (S1R) is expressed in retinal ganglion cells (RGCs) and astrocytes, and its activation is neuroprotective. We evaluated the contribution of S1R within optic nerve head astrocytes (ONHAs) to growth and survival of RGCs in vitro. Methods Wild-type (WT) RGCs and WT or S1R knockout (S1R KO) ONHAs were cocultured for 2, 4, or 7 days. Total and maximal neurite length, neurite root, and extremity counts were measured. Cell death was measured using a TUNEL assay. Signal transducer and activator of transcription 3 phosphorylation levels were evaluated in ONHA-derived lysates by immunoblotting. Results The coculture of WT RGCs with WT or S1R KO ONHAs increased the total and maximal neurite length. Neurite root and extremity counts increased at 4 and 7 days when WT RGCs were cocultured with WT or S1R KO ONHAs. At all timepoints, the total and maximal neurite length decreased for WT RGCs in coculture with S1R KO ONHAs compared with WT ONHAs. Root and extremity counts decreased for WT RGCs in coculture with S1R KO ONHAs compared with WT ONHAs at 2 and 7, but not 4 days. RGC apoptosis increased in S1R KO ONHA coculture and S1R KO-conditioned medium, compared with WT ONHA coculture or WT-conditioned medium. S1R KO ONHA-derived lysates showed decreased phosphorylated signal transducer and activator of transcription 3 levels compared with WT ONHA-derived lysates. Conclusions The absence of S1R within ONHAs has a deleterious effect on RGC neurite growth and RGC survival, reflected in analysis of WT RGC + S1R KO ONHA indirect cocultures. The data suggest that S1R may enhance ganglion cell survival via glia-mediated mechanisms.
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Affiliation(s)
- Jing Zhao
- Department of Ophthalmology, Medical College of Georgia at Augusta University, Augusta, Georgia, United States
- Culver Vision Discovery Institute, Augusta, Georgia, United States
| | | | - Barbara A. Mysona
- Department of Ophthalmology, Medical College of Georgia at Augusta University, Augusta, Georgia, United States
- Department of Cellular Biology and Anatomy, Augusta, Georgia, United States
- Culver Vision Discovery Institute, Augusta, Georgia, United States
| | - Sylvia B. Smith
- Department of Ophthalmology, Medical College of Georgia at Augusta University, Augusta, Georgia, United States
- Department of Cellular Biology and Anatomy, Augusta, Georgia, United States
- Culver Vision Discovery Institute, Augusta, Georgia, United States
| | - Kathryn E. Bollinger
- Department of Ophthalmology, Medical College of Georgia at Augusta University, Augusta, Georgia, United States
- Department of Cellular Biology and Anatomy, Augusta, Georgia, United States
- Culver Vision Discovery Institute, Augusta, Georgia, United States
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Vanhunsel S, Bergmans S, Beckers A, Etienne I, Van Bergen T, De Groef L, Moons L. The age factor in optic nerve regeneration: Intrinsic and extrinsic barriers hinder successful recovery in the short-living killifish. Aging Cell 2022; 21:e13537. [PMID: 34927348 PMCID: PMC8761009 DOI: 10.1111/acel.13537] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Revised: 11/24/2021] [Accepted: 12/03/2021] [Indexed: 01/06/2023] Open
Abstract
As the mammalian central nervous system matures, its regenerative ability decreases, leading to incomplete or non-recovery from the neurodegenerative diseases and central nervous system insults that we are increasingly facing in our aging world population. Current neuroregenerative research is largely directed toward identifying the molecular and cellular players that underlie central nervous system repair, yet it repeatedly ignores the aging context in which many of these diseases appear. Using an optic nerve crush model in a novel biogerontology model, that is, the short-living African turquoise killifish, the impact of aging on injury-induced optic nerve repair was investigated. This work reveals an age-related decline in axonal regeneration in female killifish, with different phases of the repair process being affected depending on the age. Interestingly, as in mammals, both a reduced intrinsic growth potential and a non-supportive cellular environment seem to lie at the basis of this impairment. Overall, we introduce the killifish visual system and its age-dependent regenerative ability as a model to identify new targets for neurorepair in non-regenerating individuals, thereby also considering the effects of aging on neurorepair.
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Affiliation(s)
- Sophie Vanhunsel
- Neural Circuit Development and Regeneration Research GroupAnimal Physiology and Neurobiology SectionDepartment of BiologyKU LeuvenLeuvenBelgium
| | - Steven Bergmans
- Neural Circuit Development and Regeneration Research GroupAnimal Physiology and Neurobiology SectionDepartment of BiologyKU LeuvenLeuvenBelgium
| | - An Beckers
- Neural Circuit Development and Regeneration Research GroupAnimal Physiology and Neurobiology SectionDepartment of BiologyKU LeuvenLeuvenBelgium
| | | | | | - Lies De Groef
- Neural Circuit Development and Regeneration Research GroupAnimal Physiology and Neurobiology SectionDepartment of BiologyKU LeuvenLeuvenBelgium
- Leuven Brain InstituteLeuvenBelgium
| | - Lieve Moons
- Neural Circuit Development and Regeneration Research GroupAnimal Physiology and Neurobiology SectionDepartment of BiologyKU LeuvenLeuvenBelgium
- Leuven Brain InstituteLeuvenBelgium
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Yang J, Zhang M, Song Q, Li S, Zhao X, Kan L, Zhu S. Integrating network pharmacological and experimental models to investigate the therapeutic effects of baicalein in glaucoma. Chin Med 2021; 16:124. [PMID: 34823561 PMCID: PMC8613988 DOI: 10.1186/s13020-021-00537-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2021] [Accepted: 11/13/2021] [Indexed: 12/16/2022] Open
Abstract
Background Traditional Chinese medicine (TCM) has a long history of treating glaucoma with remarkable effects, but there is no clear conclusion on its mechanism. Methods Network pharmacology and molecular docking were used to analyze the mechanism and targets of TCM in the treatment of glaucoma, and baicalein was used to treat chronic ocular hypertension animal models rats for observation. Results The results of animal experiments showed that baicalein could significantly reduce intraocular pressure (IOP) in a rat model of chronic ocular hypertension and protect the structure of the retina and optic nerve, as shown by hematoxylin–eosin (H&E) staining and transmission electron microscopy (TEM). Reducing the apoptosis of retinal ganglion cells (RGCs) by upregulating the expression of the antiapoptotic protein BCL-2 is basically consistent with the results of molecular docking. In the network pharmacology analysis, many key proteins of biological pathways involved in the herbal therapeutic processes in glaucoma, such as threonine kinase 1 (AKT1, core protein of PI3K/AKT signaling), tumor protein p53 (TP53, a tumor suppressor gene coding tumor protein P53), signal transducer and activator of transcription 3 (STAT3, core protein of JAK/STAT signaling), interleukin 6 (IL-6) and interleukin 17 (IL-17, proinflammatory factors), were identified. Their interactions built complicated chain reactions in the process of glaucoma. Conclusion By combining the analysis of network pharmacology and animal experimental results, baicalein could effectively improve the symptoms of glaucoma and reduce RGC apoptosis, suggesting that the potential mechanism of TCM in treating glaucoma is related to regulating inflammation and cellular immunity and reducing apoptosis.
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Affiliation(s)
- Jiawei Yang
- Eye School, Chengdu University of Traditional Chinese Medicine, 37 Shi Er Qiao Road, Chengdu, 610075, China
| | - Mingxu Zhang
- Eye School, Chengdu University of Traditional Chinese Medicine, 37 Shi Er Qiao Road, Chengdu, 610075, China
| | - Qiuyi Song
- Eye School, Chengdu University of Traditional Chinese Medicine, 37 Shi Er Qiao Road, Chengdu, 610075, China
| | - Siqi Li
- Eye School, Chengdu University of Traditional Chinese Medicine, 37 Shi Er Qiao Road, Chengdu, 610075, China
| | - Xiulan Zhao
- Ineye Hospital of Chengdu University of TCM, Chengdu, China
| | - Liping Kan
- Eye School, Chengdu University of Traditional Chinese Medicine, 37 Shi Er Qiao Road, Chengdu, 610075, China
| | - Siquan Zhu
- Eye School, Chengdu University of Traditional Chinese Medicine, 37 Shi Er Qiao Road, Chengdu, 610075, China. .,Department of Ophthalmology, Beijing Anzhen Hospital, Capital Medical University, Beijing, China.
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Toychiev AH, Batsuuri K, Srinivas M. Gap Junctional Coupling Between Retinal Astrocytes Exacerbates Neuronal Damage in Ischemia-Reperfusion Injury. Invest Ophthalmol Vis Sci 2021; 62:27. [PMID: 34846518 PMCID: PMC8648063 DOI: 10.1167/iovs.62.14.27] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Purpose Retinal astrocytes abundantly express connexin 43 (Cx43), a transmembrane protein that forms gap junction (GJ) channels and unopposed hemichannels. While it is well established that Cx43 is upregulated in retinal injuries, it is unclear whether astrocytic Cx43 plays a role in retinal ganglion cell (RGC) loss associated with injury. Here, we investigated the effect of astrocyte-specific deletion of Cx43 (Cx43KO) and channel inhibitors on RGC loss in retinal ischemia/reperfusion (I/R) injury and assessed changes in expression and GJ channel and hemichannel function that occur in I/R injury. The effect of Cx43 deletion on neural function in the uninjured retina was also assessed. Methods Cx43 expression, astrocyte density and morphology, and RGC death in wild-type and Cx43KO mice after I/R injury were determined using immunohistochemistry and Western blotting. Visual function was assessed using ERG recordings. GJ coupling and hemichannel activity were evaluated using tracer coupling and uptake studies, respectively. Results Loss of RGCs in I/R injury was accompanied by an increase of Cx43 expression in astrocytes. Functional studies indicated that I/R injury augmented astrocytic GJ coupling but not Cx43 hemichannel activity. Importantly, deletion of astrocytic Cx43 improved neuronal survival in acute ischemia but did not affect RGC function in the absence of injury. In support, pharmacologic inhibition of GJ coupling provided neuroprotection in I/R injury. Conclusions The increase in Cx43 expression and GJ coupling during acute I/R injury exacerbates RGC loss. Inhibition of astrocytic Cx43 channels might represent a useful strategy to promote RGC survival in pathologic conditions.
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Affiliation(s)
- Abduqodir H Toychiev
- Department of Biological and Vision Sciences, SUNY College of Optometry, New York, NY, United States
| | - Khulan Batsuuri
- Department of Biological and Vision Sciences, SUNY College of Optometry, New York, NY, United States
| | - Miduturu Srinivas
- Department of Biological and Vision Sciences, SUNY College of Optometry, New York, NY, United States
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Kirschner A, Strat AN, Yablonski J, Yoo H, Bagué T, Li H, Zhao J, Bollinger KE, Herberg S, Ganapathy PS. Mechanosensitive channel inhibition attenuates TGFβ2-induced actin cytoskeletal remodeling and reactivity in mouse optic nerve head astrocytes. Exp Eye Res 2021; 212:108791. [PMID: 34656548 DOI: 10.1016/j.exer.2021.108791] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 09/22/2021] [Accepted: 10/11/2021] [Indexed: 11/27/2022]
Abstract
Astrocytes within the optic nerve head undergo actin cytoskeletal rearrangement early in glaucoma, which coincides with astrocyte reactivity and extracellular matrix (ECM) deposition. Elevated transforming growth factor beta 2 (TGFβ2) levels within astrocytes have been described in glaucoma, and TGFβ signaling induces actin cytoskeletal remodeling and ECM deposition in many tissues. A key mechanism by which astrocytes sense and respond to external stimuli is via mechanosensitive ion channels. Here, we tested the hypothesis that inhibition of mechanosensitive channels will attenuate TGFβ2-mediated optic nerve head astrocyte actin cytoskeletal remodeling, reactivity, and ECM deposition. Primary optic nerve head astrocytes were isolated from C57BL/6J mice and cell purity was confirmed by immunostaining. Astrocytes were treated with vehicle control, TGFβ2 (5 ng/ml), GsMTx4 (a mechanosensitive channel inhibitor; 500 nM), or TGFβ2 (5 ng/ml) + GsMTx4 (500 nM) for 48 h. FITC-phalloidin staining was used to assess the formation of f-actin stress fibers and to quantify the presence of crosslinked actin networks (CLANs). Cell reactivity was determined by immunostaining and immunoblotting for GFAP. Levels of fibronectin and collagen IV deposition were also quantified. Primary optic nerve head astrocytes were positive for the astrocyte marker GFAP and negative for markers for microglia (F4/80) and oligodendrocytes (OSP1). Significantly increased %CLAN-positive cells were observed after 48-h treatment with TGFβ2 vs. control in a dose-dependent manner. Co-treatment with GsMTx4 significantly decreased %CLAN-positive cells vs. TGFβ2 treatment and the presence of f-actin stress fibers. TGFβ2 treatment significantly increased GFAP, fibronectin, and collagen IV levels, and GsMTx4 co-treatment ameliorated GFAP immunoreactivity. Our data suggest inhibition of mechanosensitive channel activity as a potential therapeutic strategy to modulate actin cytoskeletal remodeling within the optic nerve head in glaucoma.
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Affiliation(s)
- Alexander Kirschner
- Department of Ophthalmology & Visual Sciences, SUNY Upstate Medical University, Syracuse, NY, 13210, USA
| | - Ana N Strat
- Department of Ophthalmology & Visual Sciences, SUNY Upstate Medical University, Syracuse, NY, 13210, USA; Department of Neuroscience and Physiology, SUNY Upstate Medical University, Syracuse, NY, 13210, USA
| | - John Yablonski
- Department of Ophthalmology & Visual Sciences, SUNY Upstate Medical University, Syracuse, NY, 13210, USA
| | - Hannah Yoo
- Department of Ophthalmology & Visual Sciences, SUNY Upstate Medical University, Syracuse, NY, 13210, USA
| | - Tyler Bagué
- Department of Ophthalmology & Visual Sciences, SUNY Upstate Medical University, Syracuse, NY, 13210, USA
| | - Haiyan Li
- Department of Ophthalmology & Visual Sciences, SUNY Upstate Medical University, Syracuse, NY, 13210, USA; Department of Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, NY, 13210, USA; BioInspired Institute, Syracuse University, Syracuse, NY, 13244, USA
| | - Jing Zhao
- Department of Ophthalmology, Medical College of Georgia at Augusta University, Augusta, GA, 30912, USA; Culver Vision Discovery Institute, Augusta, GA, 30912, USA
| | - Kathryn E Bollinger
- Department of Ophthalmology, Medical College of Georgia at Augusta University, Augusta, GA, 30912, USA; Culver Vision Discovery Institute, Augusta, GA, 30912, USA
| | - Samuel Herberg
- Department of Ophthalmology & Visual Sciences, SUNY Upstate Medical University, Syracuse, NY, 13210, USA; Department of Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, NY, 13210, USA; BioInspired Institute, Syracuse University, Syracuse, NY, 13244, USA; Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY, 13210, USA; Department of Biomedical and Chemical Engineering, Syracuse University, Syracuse, NY, 13244, USA
| | - Preethi S Ganapathy
- Department of Ophthalmology & Visual Sciences, SUNY Upstate Medical University, Syracuse, NY, 13210, USA; Department of Neuroscience and Physiology, SUNY Upstate Medical University, Syracuse, NY, 13210, USA; BioInspired Institute, Syracuse University, Syracuse, NY, 13244, USA.
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Kumar S, Ramakrishnan H, Viswanathan S, Akopian A, Bloomfield SA. Neuroprotection of the Inner Retina Also Prevents Secondary Outer Retinal Pathology in a Mouse Model of Glaucoma. Invest Ophthalmol Vis Sci 2021; 62:35. [PMID: 34297802 PMCID: PMC8300060 DOI: 10.1167/iovs.62.9.35] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Accepted: 06/24/2021] [Indexed: 12/02/2022] Open
Abstract
Purpose We examined structural and functional changes in the outer retina of a mouse model of glaucoma. We examined whether these changes are a secondary consequence of damage in the inner retina and whether neuroprotection of the inner retina also prevents outer retinal changes. Methods We used an established microbead occlusion model of glaucoma whereby intraocular pressure (IOP) was elevated. Specific antibodies were used to label rod and cone bipolar cells (BCs), horizontal cells (HCs), and retinal ganglion cells (RGCs), as well as synaptic components in control and glaucomatous eyes, to assess structural damage and cell loss. ERG recordings were made to assess outer retina function. Results We found structural and functional damage of BCs, including significant cell loss and dendritic/axonal remodeling of HCs, following IOP elevation. The first significant loss of both BCs occurred at 4 to 5 weeks after microbead injection. However, early changes in the dendritic structure of RGCs were observed at 3 weeks, but significant changes in the rod BC axon terminal structure were not seen until 4 weeks. We found that protection of inner retinal neurons in glaucomatous eyes by pharmacological blockade of gap junctions or genetic ablation of connexin 36 largely prevented outer retinal damage. Conclusions Together, our results indicate that outer retinal impairments in glaucoma are a secondary sequalae of primary damage in the inner retina. The finding that neuroprotection of the inner retina can also prevent outer retinal damage has important implications with regard to the targets for effective neuroprotective therapy.
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Affiliation(s)
- Sandeep Kumar
- Department of Biological and Vision Sciences, State University of New York College of Optometry, New York, New York, United States
| | - Hariharasubramanian Ramakrishnan
- Department of Biological and Vision Sciences, State University of New York College of Optometry, New York, New York, United States
| | - Suresh Viswanathan
- Department of Biological and Vision Sciences, State University of New York College of Optometry, New York, New York, United States
| | - Abram Akopian
- Department of Biological and Vision Sciences, State University of New York College of Optometry, New York, New York, United States
| | - Stewart A. Bloomfield
- Department of Biological and Vision Sciences, State University of New York College of Optometry, New York, New York, United States
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Muench NA, Patel S, Maes ME, Donahue RJ, Ikeda A, Nickells RW. The Influence of Mitochondrial Dynamics and Function on Retinal Ganglion Cell Susceptibility in Optic Nerve Disease. Cells 2021; 10:cells10071593. [PMID: 34201955 PMCID: PMC8306483 DOI: 10.3390/cells10071593] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Revised: 06/15/2021] [Accepted: 06/17/2021] [Indexed: 12/30/2022] Open
Abstract
The important roles of mitochondrial function and dysfunction in the process of neurodegeneration are widely acknowledged. Retinal ganglion cells (RGCs) appear to be a highly vulnerable neuronal cell type in the central nervous system with respect to mitochondrial dysfunction but the actual reasons for this are still incompletely understood. These cells have a unique circumstance where unmyelinated axons must bend nearly 90° to exit the eye and then cross a translaminar pressure gradient before becoming myelinated in the optic nerve. This region, the optic nerve head, contains some of the highest density of mitochondria present in these cells. Glaucoma represents a perfect storm of events occurring at this location, with a combination of changes in the translaminar pressure gradient and reassignment of the metabolic support functions of supporting glia, which appears to apply increased metabolic stress to the RGC axons leading to a failure of axonal transport mechanisms. However, RGCs themselves are also extremely sensitive to genetic mutations, particularly in genes affecting mitochondrial dynamics and mitochondrial clearance. These mutations, which systemically affect the mitochondria in every cell, often lead to an optic neuropathy as the sole pathologic defect in affected patients. This review summarizes knowledge of mitochondrial structure and function, the known energy demands of neurons in general, and places these in the context of normal and pathological characteristics of mitochondria attributed to RGCs.
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Affiliation(s)
- Nicole A. Muench
- Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison, Madison, WI 53706, USA; (N.A.M.); (S.P.); (R.J.D.)
| | - Sonia Patel
- Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison, Madison, WI 53706, USA; (N.A.M.); (S.P.); (R.J.D.)
| | - Margaret E. Maes
- Institute of Science and Technology Austria, 3400 Klosterneuburg, Austria;
| | - Ryan J. Donahue
- Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison, Madison, WI 53706, USA; (N.A.M.); (S.P.); (R.J.D.)
- Boston Children’s Hospital, Harvard Medical School, Harvard University, Boston, MA 02115, USA
| | - Akihiro Ikeda
- Department of Medical Genetics, University of Wisconsin-Madison, Madison, WI 53706, USA;
- McPherson Eye Research Institute, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Robert W. Nickells
- Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison, Madison, WI 53706, USA; (N.A.M.); (S.P.); (R.J.D.)
- McPherson Eye Research Institute, University of Wisconsin-Madison, Madison, WI 53705, USA
- Correspondence:
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Zhao J, Gonsalvez G, Bartoli M, Mysona BA, Smith SB, Bollinger KE. Sigma 1 Receptor Modulates Optic Nerve Head Astrocyte Reactivity. Invest Ophthalmol Vis Sci 2021; 62:5. [PMID: 34086045 PMCID: PMC8185400 DOI: 10.1167/iovs.62.7.5] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Accepted: 05/03/2021] [Indexed: 12/04/2022] Open
Abstract
Purpose Stimulation of Sigma 1 Receptor (S1R) is neuroprotective in retina and optic nerve. S1R is expressed in both neurons and glia. The purpose of this work is to evaluate the ability of S1R to modulate reactivity responses of optic nerve head astrocytes (ONHAs) by investigating the extent to which S1R activation alters ONHA reactivity under conditions of ischemic cellular stress. Methods Wild type (WT) and S1R knockout (KO) ONHAs were derived and treated with vehicle or S1R agonist, (+)-pentazocine ((+)-PTZ). Cells were subjected to six hours of oxygen glucose deprivation (OGD) followed by 18 hours of re-oxygenation (OGD/R). Astrocyte reactivity responses were measured. Molecules that regulate ONHA reactivity, signal transducer and activator of transcription 3 (STAT3) and nuclear factor kappa B (NF-kB), were evaluated. Results Baseline glial fibrillary acidic protein (GFAP) levels were increased in nonstressed KO ONHAs compared with WT cultures. Baseline cellular migration was also increased in nonstressed KO ONHAs compared with WT. Treatment with (+)-PTZ increased cellular migration in nonstressed WT ONHAs but not in KO ONHAs. Exposure of both WT and KO ONHAs to ischemia (OGD/R), increased GFAP levels and cellular proliferation. However, (+)-PTZ treatment of OGD/R-exposed ONHAs enhanced GFAP levels, cellular proliferation, and cellular migration in WT but not KO cultures. The (+)-PTZ treatment of WT ONHAs also enhanced the OGD/R-induced increase in cellular pSTAT3 levels. However, treatment of WT ONHAs with (+)-PTZ abrogated the OGD/R-induced rise in NF-kB(p65) activation. Conclusions Under ischemic stress conditions, S1R activation enhanced ONHA reactivity characteristics. Future studies should address effects of these responses on RGC survival.
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Affiliation(s)
- Jing Zhao
- Department of Ophthalmology, Medical College of Georgia at Augusta University, Augusta, Georgia, United States
- Culver Vision Discovery Institute, Augusta, Georgia, United States
| | - Graydon Gonsalvez
- Department of Cellular Biology and Anatomy, Medical College of Georgia at Augusta University, Augusta, Georgia, United States
| | - Manuela Bartoli
- Department of Cellular Biology and Anatomy, Medical College of Georgia at Augusta University, Augusta, Georgia, United States
- Culver Vision Discovery Institute, Augusta, Georgia, United States
| | - Barbara A. Mysona
- Department of Ophthalmology, Medical College of Georgia at Augusta University, Augusta, Georgia, United States
- Department of Cellular Biology and Anatomy, Medical College of Georgia at Augusta University, Augusta, Georgia, United States
- Culver Vision Discovery Institute, Augusta, Georgia, United States
| | - Sylvia B. Smith
- Department of Ophthalmology, Medical College of Georgia at Augusta University, Augusta, Georgia, United States
- Department of Cellular Biology and Anatomy, Medical College of Georgia at Augusta University, Augusta, Georgia, United States
- Culver Vision Discovery Institute, Augusta, Georgia, United States
| | - Kathryn E. Bollinger
- Department of Ophthalmology, Medical College of Georgia at Augusta University, Augusta, Georgia, United States
- Department of Cellular Biology and Anatomy, Medical College of Georgia at Augusta University, Augusta, Georgia, United States
- Culver Vision Discovery Institute, Augusta, Georgia, United States
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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: 15] [Impact Index Per Article: 5.0] [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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Dascalu AM, Stana D, Nicolae VA, Cirstoveanu C, Vancea G, Serban D, Socea B. Association between vascular comorbidity and glaucoma progression: A four-year observational study. Exp Ther Med 2021; 21:283. [PMID: 33603890 PMCID: PMC7851678 DOI: 10.3892/etm.2021.9714] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Accepted: 11/24/2020] [Indexed: 12/23/2022] Open
Abstract
Glaucoma, one of the significant causes of blindness worldwide, is a chronic optic neuropathy, characterized by progressive loss of retinal ganglion cells and specific perimetric defects. This study aimed to assess the association between the risk of glaucoma progression and different systemic vascular abnormalities. A 4-year prospective study was carried out on 204 patients diagnosed with open-angle glaucoma. Associated systemic vascular pathology was documented in 102 cases. Progression was encountered in 57 (55.9%) patients with vascular comorbidities and only in 10 (9.8%) patients with no associated vascular diseases (OR 13.81, P<0.01). The vascular risk factors associated with glaucoma progression in the study group were diastolic hypotension (OR 5.444, P=0.027), ischemic cardiac disease (OR 5.826; P<0.01), peripheral vasospasm (OR 3.108, P=0.042) and arterial hypertension (OR 2.593, P=0.05). Diabetes was not significantly correlated with progression in the study group, but only patients without diabetic retinopathy were included. This study highlights that systemic comorbidities associated with endothelial lesions, atherosclerosis and hypoperfusion can lead to damage to the retinal nerve fiber layer and the underlying conjunctive tissue.
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Affiliation(s)
- Ana Maria Dascalu
- Faculty of Medicine, ‘Carol Davila’ University of Medicine and Pharmacy, 020021 Bucharest, Romania
- Department of Ophthalmology, Emergency University Hospital Bucharest, 050098 Bucharest, Romania
| | - Daniela Stana
- Department of Ophthalmology, Emergency University Hospital Bucharest, 050098 Bucharest, Romania
| | - Vanesa Andrada Nicolae
- Faculty of Medicine, ‘Carol Davila’ University of Medicine and Pharmacy, 020021 Bucharest, Romania
| | - Catalin Cirstoveanu
- Faculty of Medicine, ‘Carol Davila’ University of Medicine and Pharmacy, 020021 Bucharest, Romania
| | - Geta Vancea
- Faculty of Medicine, ‘Carol Davila’ University of Medicine and Pharmacy, 020021 Bucharest, Romania
| | - Dragos Serban
- Faculty of Medicine, ‘Carol Davila’ University of Medicine and Pharmacy, 020021 Bucharest, Romania
| | - Bogdan Socea
- Faculty of Medicine, ‘Carol Davila’ University of Medicine and Pharmacy, 020021 Bucharest, Romania
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Calkins DJ. Adaptive responses to neurodegenerative stress in glaucoma. Prog Retin Eye Res 2021; 84:100953. [PMID: 33640464 DOI: 10.1016/j.preteyeres.2021.100953] [Citation(s) in RCA: 54] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 02/08/2021] [Accepted: 02/19/2021] [Indexed: 12/12/2022]
Abstract
Glaucoma causes loss of vision through degeneration of the retinal ganglion cell (RGC) projection to the brain. The disease is characterized by sensitivity to intraocular pressure (IOP) conveyed at the optic nerve head, through which RGC axons pass unmyelinated to form the optic nerve. From this point, a pathogenic triumvirate comprising inflammatory, oxidative, and metabolic stress influence both proximal structures in the retina and distal structures in the optic projection. This review focuses on metabolic stress and how the optic projection may compensate through novel adaptive mechanisms to protect excitatory signaling to the brain. In the retina and proximal nerve head, the unmyelinated RGC axon segment is energy-inefficient, which leads to increased demand for adenosine-5'-triphosphate (ATP) at the risk of vulnerability to Ca2+-related metabolic and oxidative pressure. This vulnerability may underlie the bidirectional nature of progression. However, recent evidence highlights that the optic projection in glaucoma is not passive but rather demonstrates adaptive processes that may push back against neurodegeneration. In the retina, even as synaptic and dendritic pruning ensues, early progression involves enhanced excitability of RGCs. Enhancement involves depolarization of the resting membrane potential and increased response to light, independent of RGC morphological type. This response is axogenic, arising from increased levels and translocation of voltage-gated sodium channels (NaV) in the unmyelinated segment. During this same early period, large-scale networks of gap-junction coupled astrocytes redistribute metabolic resources to the optic projection stressed by elevated IOP to slow loss of axon function. This redistribution may reflect more local remodeling, as astrocyte processes respond to focal metabolic duress by boosting glycogen turnover in response to axonal activity in an effort to promote survival of the healthiest axons. Both enhanced excitability and metabolic redistribution are transient, indicating that the same adaptive mechanisms that apparently serve to slow progression ultimately may be too expensive for the system to sustain over longer periods.
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Affiliation(s)
- David J Calkins
- The Vanderbilt Eye Institute, Nashville, TN, USA; Vanderbilt Vision Research Center, Vanderbilt University Medical Center, 1161 21st Ave S, AA7100 Medical Center North Nashville, Tennessee, 37232, USA.
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Schneider M, Pawlak R, Weber GR, Dillinger AE, Kuespert S, Iozzo RV, Quigley HA, Ohlmann A, Tamm ER, Fuchshofer R. A novel ocular function for decorin in the aqueous humor outflow. Matrix Biol 2021; 97:1-19. [PMID: 33582236 DOI: 10.1016/j.matbio.2021.02.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 01/28/2021] [Accepted: 02/09/2021] [Indexed: 12/14/2022]
Abstract
Primary open-angle glaucoma, a neurodegenerative disorder characterized by degeneration of optic nerve axons, is a frequent cause of vision loss and blindness worldwide. Several randomized multicenter studies have identified intraocular pressure as the major risk factor for its development, caused by an increased outflow resistance to the aqueous humor within the trabecular meshwork. However, the molecular mechanism for increased outflow resistance in POAG has not been fully established. One of the proposed players is the pro-fibrotic transforming growth factor (TGF)-β2, which is found in higher amounts in the aqueous humor of patients with POAG. In this study we elucidated the role of decorin, a small leucine-rich proteoglycan and known antagonist of TGF-β, in the region of aqueous humor outflow tissue. Utilizing decorin deficient mice, we discovered that decorin modulated TGF-β signaling in the canonical outflow pathways and the lack of decorin in vivo caused an increase in intraocular pressure. Additionally, the Dcn-/- mice showed significant loss of optic nerve axons and morphological changes in the glial lamina, typical features of glaucoma. Moreover, using human trabecular meshwork cells we discovered that soluble decorin attenuated TGF-β2 mediated synthesis and expression of typical downstream target genes including CCN2/CTGF, FN and COL IV. Finally, we found a negative reciprocal regulation of decorin and TGF-β, with a dramatic downregulation of decorin in the canonical outflow pathways of patients with primary open-angle glaucoma. Collectively, our results indicate that decorin plays an important role in the pathogenesis of primary open-angle glaucoma and offers novel perspectives in the treatment of this serious disease.
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Affiliation(s)
- Magdalena Schneider
- Institute of Human Anatomy and Embryology, University of Regensburg, Universitätsstr. 31, Regensburg D-93053, Germany
| | - Ramona Pawlak
- Institute of Human Anatomy and Embryology, University of Regensburg, Universitätsstr. 31, Regensburg D-93053, Germany
| | - Gregor R Weber
- Department of Ophthalmology, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Andrea E Dillinger
- Institute of Human Anatomy and Embryology, University of Regensburg, Universitätsstr. 31, Regensburg D-93053, Germany
| | - Sabrina Kuespert
- Institute of Human Anatomy and Embryology, University of Regensburg, Universitätsstr. 31, Regensburg D-93053, Germany
| | - Renato V Iozzo
- Department of Pathology, Anatomy and Cell Biology and the Translational Cellular Oncology Program, Kimmel Cancer Center, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, United States
| | - Harry A Quigley
- Wilmer Eye Institute, Johns Hopkins University, Baltimore, MD, United States
| | - Andreas Ohlmann
- Department of Ophthalmology, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Ernst R Tamm
- Institute of Human Anatomy and Embryology, University of Regensburg, Universitätsstr. 31, Regensburg D-93053, Germany
| | - Rudolf Fuchshofer
- Institute of Human Anatomy and Embryology, University of Regensburg, Universitätsstr. 31, Regensburg D-93053, Germany.
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