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Zhang CJ, Mou H, Yuan J, Wang YH, Sun SN, Wang W, Xu ZH, Yu SJ, Jin K, Jin ZB. Effects of fluorescent protein tdTomato on mouse retina. Exp Eye Res 2024; 243:109910. [PMID: 38663720 DOI: 10.1016/j.exer.2024.109910] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 02/26/2024] [Accepted: 04/22/2024] [Indexed: 04/30/2024]
Abstract
Fluorescent proteins (FPs) have been widely used to investigate cellular and molecular interactions and trace biological events in many applications. Some of the FPs have been demonstrated to cause undesirable cellular damage by light-induced ROS production in vivo or in vitro. However, it remains unknown if one of the most popular FPs, tdTomato, has similar effects in neuronal cells. In this study, we discovered that tdTomato expression led to unexpected retinal dysfunction and ultrastructural defects in the transgenic mouse retina. The retinal dysfunction mainly manifested in the reduced photopic electroretinogram (ERG) responses and decreased contrast sensitivity in visual acuity, caused by mitochondrial damages characterized with cellular redistribution, morphological modifications and molecular profiling alterations. Taken together, our findings for the first time demonstrated the retinal dysfunction and ultrastructural defects in the retinas of tdTomato-transgenic mice, calling for a more careful design and interpretation of experiments involved in FPs.
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Affiliation(s)
- Chang-Jun Zhang
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Science Key Laboratory, Beijing, 100730, China
| | - Hao Mou
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Science Key Laboratory, Beijing, 100730, China
| | - Jing Yuan
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Science Key Laboratory, Beijing, 100730, China
| | - Ya-Han Wang
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Science Key Laboratory, Beijing, 100730, China
| | - Shu-Ning Sun
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Science Key Laboratory, Beijing, 100730, China
| | - Wen Wang
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Science Key Laboratory, Beijing, 100730, China
| | - Ze-Hua Xu
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Science Key Laboratory, Beijing, 100730, China
| | - Si-Jian Yu
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Science Key Laboratory, Beijing, 100730, China
| | - Kangxin Jin
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Science Key Laboratory, Beijing, 100730, China.
| | - Zi-Bing Jin
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Science Key Laboratory, Beijing, 100730, China.
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Stavropoulos D, Grewal MK, Petriti B, Chau KY, Hammond CJ, Garway-Heath DF, Lascaratos G. The Role of Mitophagy in Glaucomatous Neurodegeneration. Cells 2023; 12:1969. [PMID: 37566048 PMCID: PMC10417839 DOI: 10.3390/cells12151969] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2023] [Revised: 07/15/2023] [Accepted: 07/19/2023] [Indexed: 08/12/2023] Open
Abstract
This review aims to provide a better understanding of the emerging role of mitophagy in glaucomatous neurodegeneration, which is the primary cause of irreversible blindness worldwide. Increasing evidence from genetic and other experimental studies suggests that mitophagy-related genes are implicated in the pathogenesis of glaucoma in various populations. The association between polymorphisms in these genes and increased risk of glaucoma is presented. Reduction in intraocular pressure (IOP) is currently the only modifiable risk factor for glaucoma, while clinical trials highlight the inadequacy of IOP-lowering therapeutic approaches to prevent sight loss in many glaucoma patients. Mitochondrial dysfunction is thought to increase the susceptibility of retinal ganglion cells (RGCs) to other risk factors and is implicated in glaucomatous degeneration. Mitophagy holds a vital role in mitochondrial quality control processes, and the current review explores the mitophagy-related pathways which may be linked to glaucoma and their therapeutic potential.
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Affiliation(s)
- Dimitrios Stavropoulos
- Department of Ophthalmology, King’s College Hospital, London SE5 9RS, UK;
- Department of Ophthalmology, 417 Veterans Army Hospital (NIMTS), 11521 Athens, Greece
| | - Manjot K. Grewal
- NIHR Biomedical Research Center, Moorfields Eye Hospital and UCL Institute of Ophthalmology, London EC1V 9EL, UK
- Division of Optometry and Visual Science, School of Health Sciences, City, University of London, London EC1V 0HB, UK
| | - Bledi Petriti
- NIHR Biomedical Research Center, Moorfields Eye Hospital and UCL Institute of Ophthalmology, London EC1V 9EL, UK
- Department of Clinical & Movement Neurosciences, UCL Queens Square Institute of Neurology, London NW3 2PF, UK
| | - Kai-Yin Chau
- Department of Clinical & Movement Neurosciences, UCL Queens Square Institute of Neurology, London NW3 2PF, UK
| | - Christopher J. Hammond
- Section of Ophthalmology, School of Life Course Sciences, King’s College London, London SE1 7EH, UK
- Department of Ophthalmology, St Thomas’ Hospital, London SE1 7EH, UK
| | - David F. Garway-Heath
- NIHR Biomedical Research Center, Moorfields Eye Hospital and UCL Institute of Ophthalmology, London EC1V 9EL, UK
| | - Gerassimos Lascaratos
- Department of Ophthalmology, King’s College Hospital, London SE5 9RS, UK;
- Section of Ophthalmology, School of Life Course Sciences, King’s College London, London SE1 7EH, UK
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3
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Surma M, Anbarasu K, Dutta S, Olivera Perez LJ, Huang KC, Meyer JS, Das A. Enhanced mitochondrial biogenesis promotes neuroprotection in human pluripotent stem cell derived retinal ganglion cells. Commun Biol 2023; 6:218. [PMID: 36828933 PMCID: PMC9957998 DOI: 10.1038/s42003-023-04576-w] [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: 03/07/2022] [Accepted: 02/10/2023] [Indexed: 02/26/2023] Open
Abstract
Mitochondrial dysfunctions are widely afflicted in central nervous system (CNS) disorders with minimal understanding on how to improve mitochondrial homeostasis to promote neuroprotection. Here we have used human stem cell differentiated retinal ganglion cells (hRGCs) of the CNS, which are highly sensitive towards mitochondrial dysfunctions due to their unique structure and function, to identify mechanisms for improving mitochondrial quality control (MQC). We show that hRGCs are efficient in maintaining mitochondrial homeostasis through rapid degradation and biogenesis of mitochondria under acute damage. Using a glaucomatous Optineurin mutant (E50K) stem cell line, we show that at basal level mutant hRGCs possess less mitochondrial mass and suffer mitochondrial swelling due to excess ATP production load. Activation of mitochondrial biogenesis through pharmacological inhibition of the Tank binding kinase 1 (TBK1) restores energy homeostasis, mitigates mitochondrial swelling with neuroprotection against acute mitochondrial damage for glaucomatous E50K hRGCs, revealing a novel neuroprotection mechanism.
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Affiliation(s)
- Michelle Surma
- Department of Ophthalmology, Eugene and Marilyn Glick Eye Institute, Indiana University, Indianapolis, IN, 46202, USA
| | - Kavitha Anbarasu
- Department of Ophthalmology, Eugene and Marilyn Glick Eye Institute, Indiana University, Indianapolis, IN, 46202, USA
- Department of Medical and Molecular Genetics, Indiana University, Indianapolis, IN, 46202, USA
| | - Sayanta Dutta
- Department of Ophthalmology, Eugene and Marilyn Glick Eye Institute, Indiana University, Indianapolis, IN, 46202, USA
| | | | - Kang-Chieh Huang
- Department of Biology, Indiana University Purdue University, Indianapolis, IN, 46202, USA
| | - Jason S Meyer
- Department of Ophthalmology, Eugene and Marilyn Glick Eye Institute, Indiana University, Indianapolis, IN, 46202, USA
- Department of Medical and Molecular Genetics, Indiana University, Indianapolis, IN, 46202, USA
- Indiana University School of Medicine, Indianapolis, IN, 46202, USA
- Stark Neurosciences Research Institute, Indiana University, Indianapolis, IN, 46202, USA
| | - Arupratan Das
- Department of Ophthalmology, Eugene and Marilyn Glick Eye Institute, Indiana University, Indianapolis, IN, 46202, USA.
- Department of Medical and Molecular Genetics, Indiana University, Indianapolis, IN, 46202, USA.
- Stark Neurosciences Research Institute, Indiana University, Indianapolis, IN, 46202, USA.
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4
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Das A, Imanishi Y. Drug Discovery Strategies for Inherited Retinal Degenerations. BIOLOGY 2022; 11:1338. [PMID: 36138817 PMCID: PMC9495580 DOI: 10.3390/biology11091338] [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] [Received: 08/04/2022] [Revised: 08/31/2022] [Accepted: 09/07/2022] [Indexed: 12/03/2022]
Abstract
Inherited retinal degeneration is a group of blinding disorders afflicting more than 1 in 4000 worldwide. These disorders frequently cause the death of photoreceptor cells or retinal ganglion cells. In a subset of these disorders, photoreceptor cell death is a secondary consequence of retinal pigment epithelial cell dysfunction or degeneration. This manuscript reviews current efforts in identifying targets and developing small molecule-based therapies for these devastating neuronal degenerations, for which no cures exist. Photoreceptors and retinal ganglion cells are metabolically demanding owing to their unique structures and functional properties. Modulations of metabolic pathways, which are disrupted in most inherited retinal degenerations, serve as promising therapeutic strategies. In monogenic disorders, great insights were previously obtained regarding targets associated with the defective pathways, including phototransduction, visual cycle, and mitophagy. In addition to these target-based drug discoveries, we will discuss how phenotypic screening can be harnessed to discover beneficial molecules without prior knowledge of their mechanisms of action. Because of major anatomical and biological differences, it has frequently been challenging to model human inherited retinal degeneration conditions using small animals such as rodents. Recent advances in stem cell-based techniques are opening new avenues to obtain pure populations of human retinal ganglion cells and retinal organoids with photoreceptor cells. We will discuss concurrent ideas of utilizing stem-cell-based disease models for drug discovery and preclinical development.
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Affiliation(s)
- Arupratan Das
- Department of Ophthalmology, Eugene and Marilyn Glick Eye Institute, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Yoshikazu Imanishi
- Department of Ophthalmology, Eugene and Marilyn Glick Eye Institute, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
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Milanowski P, Kosior-Jarecka E, Łukasik U, Wróbel-Dudzińska D, Milanowska J, Khor CC, Aung T, Kocki J, Żarnowski T. Associations between OPA1, MFN1, and MFN2 polymorphisms and primary open angle glaucoma in Polish participants of European ancestry. Ophthalmic Genet 2021; 43:42-47. [PMID: 34425738 DOI: 10.1080/13816810.2021.1970197] [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: 10/20/2022]
Abstract
BACKGROUND Glaucomatous optic nerve damage is caused by selective death of retinal ganglion cells (RGCs). Another condition with underlying loss of RGCs is autosomal dominant optic atrophy (ADOA). Majority of ADOA patients have mutations in OPA1, gene responsible for mitochondrial fusion final steps. Clinical resemblance between the two diseases make genes involved in mitochondrial fusion good candidates as glaucoma genes. In this study, we investigated if selected polymorphisms of OPA1, MFN1, and MFN2 were associated with glaucoma in Polish population. METHODS Four OPA1 (rs166850, rs10451941, rs7624750, rs9851685), one MFN1 (rs2111534), and two MFN2 (rs873458, rs2295281) single nucleotide polymorphisms were investigated in 304 primary open angle glaucoma patients (204 with normal tension glaucoma, 100 with high-tension glaucoma) and 258 control subjects using RT-PCR method. RESULTS There was a significant difference in genotype frequencies of rs9851685 and rs2111534 polymorphisms between glaucoma patients and control subjects. Several genotype combinations comprising SNPs at OPA1 and MFN1 were significantly differently distributed in a three-way comparison between controls, patients with NTG and patients with HTG. None of the studied MFN2 polymorphisms was significantly associated with HTG or NTG. CONCLUSIONS In studied population, genotype CC and allele C of rs9851685 OPA1 polymorphism are NTG risk factors, whereas TT genotype and T allele of this polymorphism are protective factors against NTG. Genotype GA of rs2111534 MFN1 polymorphism is an HTG risk factor and AA genotype of this polymorphism is a protective factor against HTG. Several OPA1 and MFN2 genotype combinations are significantly associated with either increased or decreased risk of glaucoma in this population.
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Affiliation(s)
- Piotr Milanowski
- Department of Diagnostics and Microsurgery of Glaucoma, Medical University of Lublin, Lublin, Poland
| | - Ewa Kosior-Jarecka
- Department of Diagnostics and Microsurgery of Glaucoma, Medical University of Lublin, Lublin, Poland
| | - Urszula Łukasik
- Department of Diagnostics and Microsurgery of Glaucoma, Medical University of Lublin, Lublin, Poland
| | - Dominika Wróbel-Dudzińska
- Department of Diagnostics and Microsurgery of Glaucoma, Medical University of Lublin, Lublin, Poland
| | - Joanna Milanowska
- Department of Applied Psychology, Medical University of Lublin, Lublin, Poland
| | - Chiea Chuen Khor
- Laboratory of Complex Disease Genetics, Genome Institute of Singapore, Singapore
| | - Tin Aung
- Singapore Eye Research Institute, Singapore National Eye Center, Singapore
| | - Janusz Kocki
- Department of Clinical Genetics, Medical University of Lublin, Lublin, Poland
| | - Tomasz Żarnowski
- Department of Diagnostics and Microsurgery of Glaucoma, Medical University of Lublin, Lublin, Poland
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Neuroprotection in Glaucoma: NAD +/NADH Redox State as a Potential Biomarker and Therapeutic Target. Cells 2021; 10:cells10061402. [PMID: 34198948 PMCID: PMC8226607 DOI: 10.3390/cells10061402] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 05/24/2021] [Accepted: 05/27/2021] [Indexed: 02/07/2023] Open
Abstract
Glaucoma is the leading cause of irreversible blindness worldwide. Its prevalence and incidence increase exponentially with age and the level of intraocular pressure (IOP). IOP reduction is currently the only therapeutic modality shown to slow glaucoma progression. However, patients still lose vision despite best treatment, suggesting that other factors confer susceptibility. Several studies indicate that mitochondrial function may underlie both susceptibility and resistance to developing glaucoma. Mitochondria meet high energy demand, in the form of ATP, that is required for the maintenance of optimum retinal ganglion cell (RGC) function. Reduced nicotinamide adenine dinucleotide (NAD+) levels have been closely correlated to mitochondrial dysfunction and have been implicated in several neurodegenerative diseases including glaucoma. NAD+ is at the centre of various metabolic reactions culminating in ATP production—essential for RGC function. In this review we present various pathways that influence the NAD+(H) redox state, affecting mitochondrial function and making RGCs susceptible to degeneration. Such disruptions of the NAD+(H) redox state are generalised and not solely induced in RGCs because of high IOP. This places the NAD+(H) redox state as a potential systemic biomarker for glaucoma susceptibility and progression; a hypothesis which may be tested in clinical trials and then translated to clinical practice.
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7
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Molecular Genetics of Glaucoma: Subtype and Ethnicity Considerations. Genes (Basel) 2020; 12:genes12010055. [PMID: 33396423 PMCID: PMC7823611 DOI: 10.3390/genes12010055] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 12/27/2020] [Accepted: 12/28/2020] [Indexed: 12/11/2022] Open
Abstract
Glaucoma, the world’s leading cause of irreversible blindness, is a complex disease, with differential presentation as well as ethnic and geographic disparities. The multifactorial nature of glaucoma complicates the study of genetics and genetic involvement in the disease process. This review synthesizes the current literature on glaucoma and genetics, as stratified by glaucoma subtype and ethnicity. Primary open-angle glaucoma (POAG) is the most common cause of glaucoma worldwide, with the only treatable risk factor (RF) being the reduction of intraocular pressure (IOP). Genes associated with elevated IOP or POAG risk include: ABCA1, AFAP1, ARHGEF12, ATXN2, CAV1, CDKN2B-AS1, FOXC1, GAS7, GMDS, SIX1/SIX6, TMCO1, and TXNRD2. However, there are variations in RF and genetic factors based on ethnic and geographic differences; it is clear that unified molecular pathways accounting for POAG pathogenesis remain uncertain, although inflammation and senescence likely play an important role. There are similar ethnic and geographic complexities in primary angle closure glaucoma (PACG), but several genes have been associated with this disorder, including MMP9, HGF, HSP70, MFRP, and eNOS. In exfoliation glaucoma (XFG), genes implicated include LOXL1, CACNA1A, POMP, TMEM136, AGPAT1, RBMS3, and SEMA6A. Despite tremendous progress, major gaps remain in resolving the genetic architecture for the various glaucoma subtypes across ancestries. Large scale carefully designed studies are required to advance understanding of genetic loci as RF in glaucoma pathophysiology and to improve diagnosis and treatment options.
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8
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Functional imaging of mitochondria in retinal diseases using flavoprotein fluorescence. Eye (Lond) 2020; 35:74-92. [PMID: 32709959 DOI: 10.1038/s41433-020-1110-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 07/01/2020] [Accepted: 07/16/2020] [Indexed: 12/27/2022] Open
Abstract
Mitochondria are critical for cellular energy production and homeostasis. Oxidative stress and associated mitochondrial dysfunction are integral components of the pathophysiology of retinal diseases, including diabetic retinopathy (DR), age-related macular degeneration, and glaucoma. Within mitochondria, flavoproteins are oxidized and reduced and emit a green autofluorescence when oxidized following blue light excitation. Recently, a noninvasive imaging device was developed to measure retinal flavoprotein fluorescence (FPF). Thus, oxidized FPF can act as a biomarker of mitochondrial dysfunction. This review article describes the literature surrounding mitochondrial FPF imaging in retinal disease. The authors describe the role of mitochondrial dysfunction in retinal diseases, experiments using FPF as a marker of mitochondrial dysfunction in vitro, the three generations of retinal FPF imaging devices, and the peer-reviewed publications that have examined FPF imaging in patients. Finally, the authors report their own study findings. Goals were to establish normative reference levels for FPF intensity and heterogeneity in healthy eyes, to compare between healthy eyes and eyes with diabetes and DR, and to compare across stages of DR. The authors present methods to calculate a patient's expected FPF values using baseline characteristics. FPF intensity and heterogeneity were elevated in diabetic eyes compared to age-matched control eyes, and in proliferative DR compared to diabetic eyes without retinopathy. In diabetic eyes, higher FPF heterogeneity was associated with poorer visual acuity. In conclusion, while current retinal imaging modalities frequently focus on structural features, functional mitochondrial imaging shows promise as a metabolically targeted tool to evaluate retinal disease.
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Das A, Bell CM, Berlinicke CA, Marsh-Armstrong N, Zack DJ. Programmed switch in the mitochondrial degradation pathways during human retinal ganglion cell differentiation from stem cells is critical for RGC survival. Redox Biol 2020; 34:101465. [PMID: 32473993 PMCID: PMC7327961 DOI: 10.1016/j.redox.2020.101465] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Accepted: 02/13/2020] [Indexed: 01/08/2023] Open
Abstract
Retinal ganglion cell (RGC) degeneration is the root cause for vision loss in glaucoma as well as in other forms of optic neuropathy. A variety of studies have implicated abnormal mitochondrial quality control (MQC) as contributing to RGC damage and degeneration in optic neuropathies. The ability to differentiate human pluripotent stem cells (hPSCs) into RGCs provides an opportunity to study RGC MQC in great detail. Degradation of damaged mitochondria is a critical step of MQC, and here we have used hPSC-derived RGCs (hRGCs) to analyze how altered mitochondrial degradation pathways in hRGCs affect their survival. Using pharmacological methods, we have investigated the role of the proteasomal and endo-lysosomal pathways in degrading damaged mitochondria in hRGCs and their precursor stem cells. We found that upon mitochondrial damage induced by the proton uncoupler carbonyl cyanide m-chlorophenyl hydrazone (CCCP), hRGCs more efficiently degraded mitochondria than did their precursor stem cells. We further identified that for degrading damaged mitochondria, stem cells predominantly use the ubiquitine-proteasome system (UPS) while hRGCs use the endo-lysosomal pathway. UPS inhibition causes apoptosis and cell death in stem cells, while hRGC viability is dependent on the endo-lysosomal pathway but not on the UPS pathway. These findings suggest that manipulation of the endo-lysosomal pathway could be therapeutically relevant for RGC protection in treating optic neuropathies associated with mitophagy defects. Endo-lysosome dependent cell survival is also conserved in other human neurons as we found that differentiated human cerebral cortical neurons also degenerated upon endo-lysosomal inhibition but not with proteasome inhibition. Human retinal ganglion cells (hRGCs) degrade damaged mitochondria more efficiently than the origin stem cells. Human stem cells rely on the ubiquitin proteasome system (UPS) for damaged mitochondrial clearance and survival. hRGCs rely on the endo-lysosomal pathway for mitochondrial clearance and survival. Unlike stem cells, proteasomal inhibition did not cause severe cell death for hRGCs. Transition from the UPS to endo-lysosomal pathway during differentiation was also observed for cerebral cortical neurons.
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Affiliation(s)
- Arupratan Das
- Department of Ophthalmology, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD, 21231, USA.
| | - Claire M Bell
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, 21231, USA
| | - Cynthia A Berlinicke
- Department of Ophthalmology, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD, 21231, USA
| | | | - Donald J Zack
- Department of Ophthalmology, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD, 21231, USA; Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD, 21231, USA; The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, 21231, USA; Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, 21231, USA.
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10
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Trivli A, Koliarakis I, Terzidou C, Goulielmos GN, Siganos CS, Spandidos DA, Dalianis G, Detorakis ET. Normal-tension glaucoma: Pathogenesis and genetics. Exp Ther Med 2018; 17:563-574. [PMID: 30651837 PMCID: PMC6307418 DOI: 10.3892/etm.2018.7011] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Accepted: 11/21/2018] [Indexed: 12/27/2022] Open
Abstract
Normal-tension glaucoma (NTG) is a multifactorial optic neuropathy which, similar to open-angle glaucomas, is characterized by progressive retinal ganglion cell death and glaucomatous visual field loss. The major distinction of NTG from open-angle glaucomas is that the intraocular pressure (IOP) does not exceed the normal range. Missing the major risk factor and target of therapy, the elevated IOP, NTG poses a clinical challenge. Several insightful reviews have been published on the pathophysiology of NTG describing the possible underlying mechanisms. The current literature available also suggests that a significant percentage of patients with NTG (as high as 21%) have a family history of glaucoma, indicating a genetic predisposition to the disease. These facts strengthen the indication that NTG remains an enigmatic process. The aim of this review was to summarize the vascular, mechanical and genetic components considered to be responsible for NTG development and to discuss the mechanisms through which they are involved in the pathogenesis of NTG.
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Affiliation(s)
- Alexandra Trivli
- Department of Ophthalmology, Konstantopouleio-Patission General Hospital, 14233 Athens, Greece.,Section of Molecular Pathology and Human Genetics, Department of Internal Medicine, School of Medicine, University of Crete, 71003 Heraklion, Greece
| | - Ioannis Koliarakis
- Laboratory of Anatomy-Histology-Embryology, Medical School, University of Crete, 71003 Heraklion, Greece
| | - Chryssa Terzidou
- Department of Ophthalmology, Konstantopouleio-Patission General Hospital, 14233 Athens, Greece
| | - George N Goulielmos
- Section of Molecular Pathology and Human Genetics, Department of Internal Medicine, School of Medicine, University of Crete, 71003 Heraklion, Greece
| | - Charalambos S Siganos
- Department of Ophthalmology, University Hospital of Heraklion, 71110 Heraklion, Greece
| | - Demetrios A Spandidos
- Laboratory of Clinical Virology, Medical School, University of Crete, 71003 Heraklion, Greece
| | - Georgios Dalianis
- Department of Ophthalmology, Konstantopouleio-Patission General Hospital, 14233 Athens, Greece
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11
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Pietrucha-Dutczak M, Amadio M, Govoni S, Lewin-Kowalik J, Smedowski A. The Role of Endogenous Neuroprotective Mechanisms in the Prevention of Retinal Ganglion Cells Degeneration. Front Neurosci 2018; 12:834. [PMID: 30524222 PMCID: PMC6262299 DOI: 10.3389/fnins.2018.00834] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2018] [Accepted: 10/25/2018] [Indexed: 12/14/2022] Open
Abstract
Retinal neurons are not able to undergo spontaneous regeneration in response to damage. A variety of stressors, i.e., UV radiation, high temperature, ischemia, allergens, and others, induce reactive oxygen species production, resulting in consecutive alteration of stress-response gene expression and finally can lead to cell apoptosis. Neurons have developed their own endogenous cellular protective systems. Some of them are preventing cell death and others are allowing functional recovery after injury. The high efficiency of these mechanisms is crucial for cell survival. In this review we focus on the contribution of the most recently studied endogenous neuroprotective factors involved in retinal ganglion cell (RGC) survival, among which, neurotrophic factors and their signaling pathways, processes regulating the redox status, and different pathways regulating cell death are the most important. Additionally, we summarize currently ongoing clinical trials for therapies for RGC degeneration and optic neuropathies, including glaucoma. Knowledge of the endogenous cellular protective mechanisms may help in the development of effective therapies and potential novel therapeutic targets in order to achieve progress in the treatment of retinal and optic nerve diseases.
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Affiliation(s)
- Marita Pietrucha-Dutczak
- Chair and Department of Physiology, School of Medicine in Katowice, Medical University of Silesia, Katowice, Poland
| | - Marialaura Amadio
- Department of Drug Sciences, Section of Pharmacology, University of Pavia, Pavia, Italy
| | - Stefano Govoni
- Department of Drug Sciences, Section of Pharmacology, University of Pavia, Pavia, Italy
| | - Joanna Lewin-Kowalik
- Chair and Department of Physiology, School of Medicine in Katowice, Medical University of Silesia, Katowice, Poland
| | - Adrian Smedowski
- Chair and Department of Physiology, School of Medicine in Katowice, Medical University of Silesia, Katowice, Poland
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12
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Guo X, Jiang Q, Tuccitto A, Chan D, Alqawlaq S, Won GJ, Sivak JM. The AMPK-PGC-1α signaling axis regulates the astrocyte glutathione system to protect against oxidative and metabolic injury. Neurobiol Dis 2018; 113:59-69. [PMID: 29438738 DOI: 10.1016/j.nbd.2018.02.004] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Revised: 01/10/2018] [Accepted: 02/08/2018] [Indexed: 02/04/2023] Open
Abstract
Neurons are highly sensitive to metabolic and oxidative injury, but endogenous astrocyte mechanisms have a critical capacity to provide protection from these stresses. We previously reported that the master regulator PGC-1α (peroxisome proliferator-activated receptor gamma coactivator-1α) is necessary for retinal astrocytes to mount effective injury responses, with particular regard to oxidative stress. Yet, this pathway has not been well studied in glia. PGC-1α is a transcriptional co-activator that is dysregulated in a variety of neurodegenerative diseases. It functions as a master regulator of cellular bioenergetics, with the ability to regulate tissue specific responses. A key inducer of PGC-1α signaling is adenosine monophosphate-activated kinase (AMPK). Thus, the AMPK-PGC-1α signaling axis coordinates metabolic and oxidative damage responses in the central nervous system (CNS). Here we report that AMPK selectively regulates expression of GCLM (glutamate cysteine ligase modulatory subunit) in astrocytes, but not neurons, through PGC-1α activation. Glutamate cysteine ligase (GCL) is the rate limiting enzyme in the biosynthesis of glutathione (GSH); a critical antioxidant and detoxifying peptide in the CNS. Through this mechanism we describe PGC-1α-dependent induction of GSH synthesis and antioxidant activity in astrocytes, and in the rodent retina in vivo. Furthermore, we demonstrate that therapeutic agonism of this pathway with the AMP mimetic, AICAR, rescues GSH levels in vivo, while reducing RGC death and astrocyte reactivity, following retinal ischemia/reperfusion injury. This mechanism presents a novel strategy for enhancing protective astrocyte antioxidant capacity in the CNS.
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Affiliation(s)
- Xiaoxin Guo
- Krembil Research Institute, University Health Network, Toronto, Ontario, Canada; Department of Ophthalmology and Vision Science, University of Toronto, Toronto, Ontario, Canada
| | - Qi Jiang
- Krembil Research Institute, University Health Network, Toronto, Ontario, Canada; Department of Ophthalmology and Vision Science, University of Toronto, Toronto, Ontario, Canada; Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | - Alessandra Tuccitto
- Krembil Research Institute, University Health Network, Toronto, Ontario, Canada; Department of Ophthalmology and Vision Science, University of Toronto, Toronto, Ontario, Canada; Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | - Darren Chan
- Krembil Research Institute, University Health Network, Toronto, Ontario, Canada; Department of Ophthalmology and Vision Science, University of Toronto, Toronto, Ontario, Canada
| | - Samih Alqawlaq
- Krembil Research Institute, University Health Network, Toronto, Ontario, Canada; Department of Ophthalmology and Vision Science, University of Toronto, Toronto, Ontario, Canada; Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | - Gah-Jone Won
- Krembil Research Institute, University Health Network, Toronto, Ontario, Canada; Department of Ophthalmology and Vision Science, University of Toronto, Toronto, Ontario, Canada
| | - Jeremy M Sivak
- Krembil Research Institute, University Health Network, Toronto, Ontario, Canada; Department of Ophthalmology and Vision Science, University of Toronto, Toronto, Ontario, Canada; Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada.
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Kamel K, Farrell M, O'Brien C. Mitochondrial dysfunction in ocular disease: Focus on glaucoma. Mitochondrion 2017; 35:44-53. [PMID: 28499981 DOI: 10.1016/j.mito.2017.05.004] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Revised: 03/08/2017] [Accepted: 05/08/2017] [Indexed: 12/21/2022]
Abstract
Mitochondrial dysfunction commonly presents with ocular findings as a part of a systemic disorder. These ophthalmic manifestations can be the first sign of a mitochondrial abnormality, which highlights the key role of a comprehensive ophthalmic assessment. On the other hand, a number of visually disabling genetic and acquired eye diseases with no curative treatment show abnormal mitochondrial function. Recent advances in mitochondrial research have improved our understanding of previously unexplained ocular disorders utilising better diagnostic approaches. Further studies on mitochondrial dysfunction and novel modalities of treatment will help to improve outcomes of these conditions. In this review article we discuss the clinical picture of common mitochondrial-related eye diseases, diagnostic approaches and possible treatment options including a very recent interesting report about gene therapy, with a particular focus on glaucoma.
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Affiliation(s)
- Khalid Kamel
- Institute of Ophthalmology, Mater Misericordiae University Hospital, Dublin, Ireland
| | | | - Colm O'Brien
- Institute of Ophthalmology, Mater Misericordiae University Hospital, Dublin, Ireland.
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Osborne NN, Núñez-Álvarez C, Joglar B, Del Olmo-Aguado S. Glaucoma: Focus on mitochondria in relation to pathogenesis and neuroprotection. Eur J Pharmacol 2016; 787:127-33. [PMID: 27090928 DOI: 10.1016/j.ejphar.2016.04.032] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Revised: 03/25/2016] [Accepted: 04/14/2016] [Indexed: 12/23/2022]
Abstract
Primary open-angle glaucoma (POAG) is a common form of glaucoma in which retinal ganglion cells (RGCs) die at varying intervals. Primary open-angle glaucoma is often associated with an increased intraocular pressure (IOP), which when reduced, can slow down the progression of the disease. However, it is essential to develop better modes of treatments for glaucoma patients. In this overview, we discuss the hypothesis that RGC mitochondria are affected during the initiation of POAG, by becoming gradually weakened, but at different rates because of their specific receptor profiles. With this in mind, we argue that neuroprotection in the context of glaucoma should focus on preserving RGC mitochondrial function and suggest a number of ways by which this can theoretically be achieved. Since POAG is a chronic disease, any neuroprotective treatment strategy must be tolerated over many years. Theoretically, topically applied substances should have the fewest side effects, but it is questionable whether sufficient compounds can reach RGC mitochondria to be effective. Therefore, other delivery procedures that might result in greater concentrations of neuroprotectants reaching RGC mitochondria are being developed. Red-light therapy represents another therapeutic alternative for enhancing RGC mitochondrial functions and has the advantage of being both non-toxic and non-invasive.
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Affiliation(s)
- Neville N Osborne
- Fundación de Investigación Oftalmológica, Avda. Doctores Fernández-Vega 34, E-33012 Oviedo, Asturias, Spain.
| | - Claudia Núñez-Álvarez
- Fundación de Investigación Oftalmológica, Avda. Doctores Fernández-Vega 34, E-33012 Oviedo, Asturias, Spain
| | - Belen Joglar
- Fundación de Investigación Oftalmológica, Avda. Doctores Fernández-Vega 34, E-33012 Oviedo, Asturias, Spain
| | - Susana Del Olmo-Aguado
- Fundación de Investigación Oftalmológica, Avda. Doctores Fernández-Vega 34, E-33012 Oviedo, Asturias, Spain
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15
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Kumar S, Malik MA, Goswami S, Sihota R, Kaur J. Candidate genes involved in the susceptibility of primary open angle glaucoma. Gene 2016; 577:119-31. [PMID: 26621382 DOI: 10.1016/j.gene.2015.11.032] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Revised: 11/05/2015] [Accepted: 11/23/2015] [Indexed: 12/30/2022]
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16
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Mastropasqua R, Fasanella V, Agnifili L, Fresina M, Di Staso S, Di Gregorio A, Marchini G, Ciancaglini M. Advance in the pathogenesis and treatment of normal-tension glaucoma. PROGRESS IN BRAIN RESEARCH 2015; 221:213-32. [PMID: 26518080 DOI: 10.1016/bs.pbr.2015.05.007] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Normal-tension glaucoma (NTG) is a multifactorial disease where mechanical stresses and vascular alterations to the optic nerve head probably represent the key pathogenic moments. Although intraocular pressure (IOP) plays a crucial role in the retinal ganglion cell loss, the IOP reduction does not necessarily reduces the disease progression. Therefore, several IOP-independent factors such as glutamate toxicity, oxidative stress, autoimmunity, and vascular dysregulation have been considered in the pathogenesis of NTG. Numerous evidences documented an impairment of the ocular blood flow, involved both in the onset and progression of the disease. The IOP reduction remains the main strategy to reduce the damage progression in NTG. Recently, new treatment strategies have been proposed to improve the control of the disease. Neuroprotection is a rapidly expanding area of research, which represents a promising tool. In the present review, we summarize the recent scientific advancements in the pathogenesis and treatment of NTG.
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Affiliation(s)
- Rodolfo Mastropasqua
- Ophthalmology Unit Department of Neurological, Neuropsychological, Morphological and Movement Sciences, University of Verona, Verona, Italy
| | - Vincenzo Fasanella
- Department of Medicine and Aging Science, Ophthalmology Clinic, University G. d'Annunzio of Chieti-Pescara, Chieti, Italy
| | - Luca Agnifili
- Department of Medicine and Aging Science, Ophthalmology Clinic, University G. d'Annunzio of Chieti-Pescara, Chieti, Italy
| | - Michela Fresina
- Department of Specialist, Diagnostics and Experimental Medicine (DIMES), Ophthalmology Service, University of Bologna, Bologna, Italy
| | - Silvio Di Staso
- Ophthalmic Clinic Department of Surgical Science, Eye Clinic, University of L'Aquila, L'Aquila, Italy
| | - Angela Di Gregorio
- Ophthalmic Clinic Department of Surgical Science, Eye Clinic, University of L'Aquila, L'Aquila, Italy
| | - Giorgio Marchini
- Ophthalmology Unit Department of Neurological, Neuropsychological, Morphological and Movement Sciences, University of Verona, Verona, Italy
| | - Marco Ciancaglini
- Ophthalmic Clinic Department of Surgical Science, Eye Clinic, University of L'Aquila, L'Aquila, Italy.
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Abstract
Mitochondrial dysfunction underlies many human disorders, including those that affect the visual system. The retinal ganglion cells, whose axons form the optic nerve, are often damaged by mitochondrial-related diseases which result in blindness. Both mitochondrial DNA (mtDNA) and nuclear gene mutations impacting many different mitochondrial processes can result in optic nerve disease. Of particular importance are mutations that impair mitochondrial network dynamics (fusion and fission), oxidative phosphorylation (OXPHOS), and formation of iron-sulfur complexes. Current genetic knowledge can inform genetic counseling and suggest strategies for novel gene-based therapies. Identifying new optic neuropathy-causing genes and defining the role of current and novel genes in disease will be important steps toward the development of effective and potentially neuroprotective therapies.
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Affiliation(s)
- Janey L Wiggs
- Department of Ophthalmology, Harvard Medical School and Massachusetts Eye and Ear, Boston, Massachusetts 02114;
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Pinazo-Durán MD, Zanón-Moreno V, Gallego-Pinazo R, García-Medina JJ. Oxidative stress and mitochondrial failure in the pathogenesis of glaucoma neurodegeneration. PROGRESS IN BRAIN RESEARCH 2015; 220:127-53. [PMID: 26497788 DOI: 10.1016/bs.pbr.2015.06.001] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
This review focuses on oxidative stress and mitochondrial failure for understanding mechanisms of optic nerve damage in primary open-angle glaucoma. The chapter shows scientific evidence for the role of mitochondrial disbalance and reactive oxygen species in glaucoma neurodegeneration. Mitochondria regulate important cellular functions including reactive oxygen species generation and apoptosis. Mitochondrial alterations result from a wide variety of damaging sources. Reactive oxygen species formed by the mitochondria can act as signaling molecules, inducing lipid peroxidation and/or excitotoxicity with the result of cell lesion and death. Antioxidants may help to counteract oxidative stress and to promote neuroprotection. We provide information that may lead to a new way for diagnosing and treating glaucoma patients.
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Affiliation(s)
- Maria D Pinazo-Durán
- Ophthalmic Research Unit "Santiago Grisolía", University Hospital Dr. Peset, Valencia, Spain; Department of Surgery/Ophthalmology, Faculty of Medicine and Odontology, University of Valencia, Valencia, Spain.
| | - Vicente Zanón-Moreno
- Ophthalmic Research Unit "Santiago Grisolía", University Hospital Dr. Peset, Valencia, Spain; Department of Surgery/Ophthalmology, Faculty of Medicine and Odontology, University of Valencia, Valencia, Spain
| | - Roberto Gallego-Pinazo
- Ophthalmic Research Unit "Santiago Grisolía", University Hospital Dr. Peset, Valencia, Spain; Department of Ophthalmology, University and Polytechnic Hospital la Fe, Valencia, Spain
| | - José J García-Medina
- Ophthalmic Research Unit "Santiago Grisolía", University Hospital Dr. Peset, Valencia, Spain; Department of Ophthalmology, University Hospital Reina Sofia, Murcia, Spain; Department of Ophthalmology and Optometry, University of Murcia, Murcia, Spain
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Doucette LP, Rasnitsyn A, Seifi M, Walter MA. The interactions of genes, age, and environment in glaucoma pathogenesis. Surv Ophthalmol 2015; 60:310-26. [PMID: 25907525 DOI: 10.1016/j.survophthal.2015.01.004] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Revised: 01/27/2015] [Accepted: 01/29/2015] [Indexed: 12/30/2022]
Abstract
Glaucoma, a progressive degenerative condition that results in the death of retinal ganglion cells, is one of the leading causes of blindness, affecting millions worldwide. The mechanisms underlying glaucoma are not well understood, although years of studies have shown that the largest risk factors are elevated intraocular pressure, age, and genetics. Eleven genes and multiple loci have been identified as contributing factors. These genes act by a number of mechanisms, including mechanical stress, ischemic/oxidative stress, and neurodegeneration. We summarize the recent advances in the understanding of glaucoma and propose a unified hypothesis for glaucoma pathogenesis. Glaucoma does not result from a single pathological mechanism, but rather a combination of pathways that are influenced by genes, age, and environment. In particular, we hypothesize that, in the presence of genetic risk factors, exposure to environment stresses results in an earlier age of onset for glaucoma. This hypothesis is based upon the overlap of the molecular pathways in which glaucoma genes are involved. Because of the interactions between these processes, it is likely that there are common therapies that may be effective for different subtypes of glaucoma.
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Affiliation(s)
- Lance P Doucette
- Faculty of Medicine and Dentistry, Department of Medical Genetics, Edmonton, Alberta T6G 2H7, Canada
| | - Alexandra Rasnitsyn
- Faculty of Medicine and Dentistry, Department of Medical Genetics, Edmonton, Alberta T6G 2H7, Canada
| | - Morteza Seifi
- Faculty of Medicine and Dentistry, Department of Medical Genetics, Edmonton, Alberta T6G 2H7, Canada
| | - Michael A Walter
- Faculty of Medicine and Dentistry, Department of Medical Genetics, Edmonton, Alberta T6G 2H7, Canada.
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20
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Zhou Y, Shuai P, Li X, Liu X, Wang J, Yang Y, Hao F, Lin H, Zhang D, Gong B. Association of SOD2 polymorphisms with primary open angle glaucoma in a Chinese population. Ophthalmic Genet 2014; 36:43-9. [PMID: 25417767 DOI: 10.3109/13816810.2014.985844] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
BACKGROUND Genetic factors have been studied extensively for their role in the pathogenesis of primary open angle glaucoma (POAG). This study was conducted to investigate whether manganese superoxide dismutase (SOD2) variants play a significant role in POAG in a Chinese population. METHODS This study included of 416 unrelated POAG patients and 997 unrelated control subjects. Four SOD2 tag single nucleotide polymorphisms (SNPs), including rs6917589 rs2842980, rs5746136 and rs4880, were genotyped by dye terminator-based SNaPshot method. The genotype and allele frequencies were evaluated using the χ(2) tests. RESULTS Allelic association analysis showed that there were suggestive differences in the allelic distributions between POAG cases and controls for SNPs rs6917589 and rs5746136 (p = 0.0.046 and p = 0.032, respectively), but no statistically significant association was detected between the two SNPs and POAG after Bonferroni correction (p > 0.0125). The allele and genotype frequency in SNPs rs2842980 and rs4880 showed no statistically significant difference between POAG cases and controls (p = 0.128 and p = 0.867, respectively). SNP rs5746136 had a significant association with POAG in the recessive model (p = 0.003155). Haplotype ATGT generated from the four SNPs showed a trend of association with POAG (p = 0.0098). CONCLUSION Our results showed a trend of association with POAG, suggesting that SOD2 may play a significant role in the development of POAG in the Chinese population. Further work with a larger sample size and functional study is needed to confirm the importance of the SOD2 gene in the pathogenesis of glaucoma.
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Affiliation(s)
- Yu Zhou
- Sichuan Key Laboratory for Disease Gene Study
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21
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Abstract
Normal tension glaucoma (NTG) is a progressive optic neuropathy that mimics primary open-angle glaucoma, but lacks the findings of elevated intraocular pressure or other mitigating factors that can lead to optic neuropathy. The present review summarized the causes, genetics, and mechanisms underlying NTG in both animal models and human patients. We also proposed that the neurovascular unit is a therapeutic target for NTG management.
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Affiliation(s)
- Xue-Song Mi
- Department of Ophthalmology, The First Affiliated Hospital of Jinan University, Guangzhou, People's Republic of China ; Department of Anatomy, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, People's Republic of China
| | - Ti-Fei Yuan
- School of Psychology, Nanjing Normal University, Nanjing, People's Republic of China ; Department of Ophthalmology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, People's Republic of China
| | - Kwok-Fai So
- Department of Anatomy, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, People's Republic of China ; Department of Ophthalmology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, People's Republic of China ; GHM Institute of CNS Regeneration, Jinan University, Guangzhou, People's Republic of China
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PGC-1α signaling coordinates susceptibility to metabolic and oxidative injury in the inner retina. THE AMERICAN JOURNAL OF PATHOLOGY 2014; 184:1017-1029. [PMID: 24508229 DOI: 10.1016/j.ajpath.2013.12.012] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Revised: 11/29/2013] [Accepted: 12/05/2013] [Indexed: 02/06/2023]
Abstract
Retinal ganglion cells (RGCs), used as a common model of central nervous system injury, are particularly vulnerable to metabolic and oxidative damage. However, molecular mechanisms underlying this sensitivity have not been determined in vivo. PGC-1α (encoded by PPARGC1A) regulates adaptive metabolism and oxidative stress responses in a tissue- and cell-specific manner. Aberrant PGC-1α signaling is implicated in neurodegeneration, but the mechanism underlying its role in central nervous system injury remains unclear. We provide evidence from a mouse model that PGC-1α expression and activity are induced in adult retina in response to metabolic and oxidative challenge. Deletion of Ppargc1a dramatically increased RGC loss, in association with dysregulated expression of PGC-1α target metabolic and oxidative stress response genes, including Hmox1 (encoding HO-1), Tfam, and Vegfa. Vehicle-treated and naive Ppargc1a(-/-) mice also showed mild RGC loss, and surprisingly prominent and consistent retinal astrocyte reactivity. These cells critically regulate metabolic homeostasis in the inner retina. We show that PGC-1α signaling (not previously studied in glia) regulates detoxifying astrocyte responses to hypoxic and oxidative stresses. Finally, PGC-1α expression was modulated in the inner retina with age and in a model of chronic optic neuropathy. These data implicate PGC-1α signaling as an important regulator of astrocyte reactivity and RGC homeostasis to coordinate pathogenic susceptibility to metabolic and oxidative injury in the inner retina.
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Janssen SF, Gorgels TG, Ramdas WD, Klaver CC, van Duijn CM, Jansonius NM, Bergen AA. The vast complexity of primary open angle glaucoma: Disease genes, risks, molecular mechanisms and pathobiology. Prog Retin Eye Res 2013; 37:31-67. [DOI: 10.1016/j.preteyeres.2013.09.001] [Citation(s) in RCA: 131] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2013] [Revised: 07/26/2013] [Accepted: 09/03/2013] [Indexed: 12/21/2022]
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Banerjee D, Banerjee A, Mookherjee S, Vishal M, Mukhopadhyay A, Sen A, Basu A, Ray K. Mitochondrial genome analysis of primary open angle glaucoma patients. PLoS One 2013; 8:e70760. [PMID: 23940637 PMCID: PMC3733777 DOI: 10.1371/journal.pone.0070760] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2013] [Accepted: 06/23/2013] [Indexed: 12/24/2022] Open
Abstract
Primary open angle glaucoma (POAG) is a multi-factorial optic disc neuropathy characterized by accelerating damage of the retinal ganglion cells and atrophy of the optic nerve head. The vulnerability of the optic nerve damage leading to POAG has been postulated to result from oxidative stress and mitochondrial dysfunction. In this study, we investigated the possible involvement of the mitochondrial genomic variants in 101 patients and 71 controls by direct sequencing of the entire mitochondrial genome. The number of variable positions in the mtDNA with respect to the revised Cambridge Reference Sequence (rCRS), have been designated "Segregating Sites". The segregating sites present only in the patients or controls have been designated "Unique Segregating Sites (USS)". The population mutation rate (θ = 4Neμ) as estimated by Watterson's θ (θw), considering only the USS, was significantly higher among the patients (p = 9.8 × 10(-15)) compared to controls. The difference in θw and the number of USS were more pronounced when restricted to the coding region (p<1.31 × 10(-21) and p = 0.006607, respectively). Further analysis of the region revealed non-synonymous variations were significantly higher in Complex I among the patients (p = 0.0053). Similar trends were retained when USS was considered only within complex I (frequency 0.49 vs 0.31 with p<0.0001 and mutation rate p-value <1.49×10(-43)) and ND5 within its gene cluster (frequency 0.47 vs 0.23 with p<0.0001 and mutation rate p-value <4.42×10(-47)). ND5 is involved in the proton pumping mechanism. Incidentally, glaucomatous trabecular meshwork cells have been reported to be more sensitive to inhibition of complex I activity. Thus mutations in ND5, expected to inhibit complex I activity, could lead to generation of oxidative stress and favor glaucomatous condition.
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Affiliation(s)
- Deblina Banerjee
- Molecular & Human Genetics Division, CSIR-Indian Institute of Chemical Biology, Kolkata, India
| | - Antara Banerjee
- Molecular & Human Genetics Division, CSIR-Indian Institute of Chemical Biology, Kolkata, India
| | - Suddhasil Mookherjee
- Molecular & Human Genetics Division, CSIR-Indian Institute of Chemical Biology, Kolkata, India
| | - Mansi Vishal
- Molecular & Human Genetics Division, CSIR-Indian Institute of Chemical Biology, Kolkata, India
- CSIR-Institute of Genomics and Integrative Biology, Delhi, India
| | | | | | - Analabha Basu
- National Institute of Biomedical Genomics, Kalyani, India
| | - Kunal Ray
- Molecular & Human Genetics Division, CSIR-Indian Institute of Chemical Biology, Kolkata, India
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Abu-Amero KK, Kondkar AA, Mousa A, Osman EA, Al-Obeidan SA. Association of Mn-SOD Mutation (c.47T > C) with Various POAG Clinical Indices. Ophthalmic Genet 2013; 35:85-90. [DOI: 10.3109/13816810.2013.796390] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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26
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Chen Y, Jia X, Wang P, Xiao X, Li S, Guo X, Zhang Q. Mutation survey of the optic atrophy 1 gene in 193 Chinese families with suspected hereditary optic neuropathy. Mol Vis 2013; 19:292-302. [PMID: 23401657 PMCID: PMC3566897] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2012] [Accepted: 02/04/2013] [Indexed: 11/13/2022] Open
Abstract
PURPOSE Dominant optic atrophy (DOA) is the most common form of autosomal inherited optic neuropathy, mainly caused by mutations in the optic atrophy 1 (OPA1) gene. The purpose of this study was to detect OPA1 gene mutations and associated phenotypes in Chinese patients with suspected hereditary optic neuropathy. METHODS A cohort of 193 Chinese families with suspected hereditary optic neuropathy was collected, which had been excluded from the three common primary mitochondrial DNA mutations associated with Leber hereditary optic neuropathy in our prior screening. Sanger sequencing was used to analyze variants in the coding and adjacent regions of OPA1. RESULTS In this study, 11 heterozygous OPA1 mutations, among which eight were novel and three were known, were identified in 12 of the 193 families (6.2%) but in none of the 192 control individuals. These novel mutations consisted of two nonsense mutations (p.E707* and p.K797*), two missense mutations (p.T330S and p.V377I), two deletions (p.S64fs and p.L331fs), one small insertion (p.L17fs), and one splice site mutation (c.2614-2A>G). Of the 12 families, three had a family history of optic neuropathy while nine were sporadic cases. Analysis of the family members in the two sporadic cases demonstrated that one parent in each of the two families had the OPA1 mutation and mild phenotype of optic atrophy. A 4-year-old boy with severe ocular phenotype was found to be compound heterozygous for two OPA1 mutations, a p.S64fs frameshift deletion and a p.V377I missense mutation, possibly implying an additive effect. CONCLUSIONS This study implies that the frequency of DOA is much lower than that of Leber hereditary optic neuropathy in Chinese compared with other ethnic groups. Lack of awareness of the mild phenotype of DOA may contribute to the low frequency of OPA1-related DOA in Chinese. The phenotype associated with compound heterozygous OPA1 mutations may suggest a possible addictive effect.
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Association of OPA1 polymorphisms with NTG and HTG: a meta-analysis. PLoS One 2012; 7:e42387. [PMID: 22879959 PMCID: PMC3411762 DOI: 10.1371/journal.pone.0042387] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2012] [Accepted: 07/04/2012] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Genetic polymorphisms of the Optic atrophy 1 gene have been implicated in altering the risk of primary open angle glaucoma (POAG), especially the susceptibility to normal tension glaucoma (NTG), but the results remain controversial. METHODS Multiple electronic databases (up to January 20, 2012) were searched independently by two investigators. A meta-analysis was performed on the association between Optic atrophy 1 polymorphisms (rs 166850 and rs 10451941) and normal tension glaucoma (NTG)/high tension glaucoma (HTG). Summary odds ratios (ORs) and 95% confidence intervals (CI) were estimated. RESULTS Seven studies of 713 cases and 964 controls for NTG and five studies of 1200 cases and 971 controls for HTG on IVS8+4C>T (rs 166850) and IVS8+32T>C (rs10451941) were identified. There were significant associations between the OPA1 rs10451941polymorphism and NTG susceptibility for all genetic models(C vs. T OR = 1.26, 95% CI 1.09-1.47, p = 0.002; CC vs. TT: OR = 1.52, 95% CI 1.04-2.20, p = 0.029; CC vs. CT+TT: OR = 1.64, 95% CI 1.16-2.33, p = 0.005; CC+CT vs. TT: OR = 1.21, 95% CI 1.02-1.44, p = 0.032). However, no evidence of associations was detected between the OPA1 IVS8+32C>T polymorphism and POAG susceptibility to HTG. Similarly, clear associations between the rs 166850 variant and NTG were observed in allelic and dominant models (T vs. C OR = 1.52, 95% CI 1.16-1.99, p = 0.002; TT+TC vs. CC OR = 1.50, 95% CI 1.13-2.01, p = 0.006) but not to HTG. In subgroup analyses by ethnicity, we detected an association between both OPA1 polymorphisms and risk for NTG in Caucasians but not in Asians. By contrast, no significant findings were noted between OPA1 variants for HTG, either in Caucasians or in Asians. CONCLUSIONS Both the IVS8+4C>T and IVS8+32T>C variants may affect individual susceptibility to NTG. Moreover, stratified analyses for NTG detecting the effects of both OPA1 polymorphisms seemed to vary with ethnicity. Further investigations are needed to validate the association.
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Novel optineurin mutations in sporadic amyotrophic lateral sclerosis patients. Neurobiol Aging 2012; 33:1016.e1-7. [DOI: 10.1016/j.neurobiolaging.2011.05.019] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2011] [Revised: 05/10/2011] [Accepted: 05/25/2011] [Indexed: 01/02/2023]
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Mitochondrial dysfunction in glaucoma: Understanding genetic influences. Mitochondrion 2012; 12:202-12. [DOI: 10.1016/j.mito.2011.11.004] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2011] [Accepted: 11/11/2011] [Indexed: 12/27/2022]
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Abstract
PURPOSE OF REVIEW Mitochondrial disease is a heterogeneous group of energy metabolism disorders that present across all ages with a wide range of ocular or multisystemic manifestations. This review focuses on recent progress made toward understanding the various ophthalmologic manifestations of primary mitochondrial diseases and discusses the implications of mitochondrial dysfunction, placing particular emphasis on recent investigations into the pathogenesis and emerging therapies for mitochondrial-based ophthalmologic disorders. RECENT FINDINGS Novel pathogenic mitochondrial DNA mutations continue to be detected in diverse ethnic populations for primary mitochondrial ophthalmologic disorders that commonly affect the optic nerve, retina, and extraocular muscles. Promising antioxidant and gene therapy approaches are being actively investigated to treat these ophthalmologic manifestations, as in Leber's hereditary optic neuropathy. Mitochondrial dysfunction is also increasingly implicated in common ophthalmologic disorders of aging, including diabetic retinopathy, age-related macular degeneration, and glaucoma. Several proteins recently recognized to play a role in the mitochondrial oxidative stress response within retinal cells, such as prohibitin and MMP2, may serve as novel biomarkers and therapeutic targets for common ophthalmologic disorders. Therapies that inhibit mitochondrial function and induce apoptosis within tumor cells, such as EDL-155 and curcumin, may offer novel therapeutic agents for ocular neoplasms such as retinoblastoma and uveal melanoma. SUMMARY Primary mitochondrial genetic disease manifestations can involve almost all aspects of the eye. Mitochondrial dysfunction is increasingly recognized as playing a causative role in the common ophthalmologic disorders in aging. This understanding has unleashed a range of emerging therapeutic approaches for mitochondrial-based ophthalmologic disorders directed at optimizing mitochondrial function.
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Van Bergen NJ, Chakrabarti R, O’Neill EC, Crowston JG, Trounce IA. Mitochondrial disorders and the eye. Eye Brain 2011; 3:29-47. [PMID: 28539774 PMCID: PMC5436186 DOI: 10.2147/eb.s16192] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The clinical significance of disturbed mitochondrial function in the eye has emerged since mitochondrial DNA (mtDNA) mutation was described in Leber's hereditary optic neuropathy. The spectrum of mitochondrial dysfunction has become apparent through increased understanding of the contribution of nuclear and somatic mtDNA mutations to mitochondrial dynamics and function. Common ophthalmic manifestations of mitochondrial dysfunction include optic atrophy, pigmentary retinopathy, and ophthalmoplegia. The majority of patients with ocular manifestations of mitochondrial disease also have variable central and peripheral nervous system involvement. Mitochondrial dysfunction has recently been associated with age-related retinal disease including macular degeneration and glaucoma. Therefore, therapeutic targets directed at promoting mitochondrial biogenesis and function offer a potential to both preserve retinal function and attenuate neurodegenerative processes.
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Affiliation(s)
- Nicole J Van Bergen
- Centre for Eye Research Australia, Department of Ophthalmology, University of Melbourne, Victoria, Australia
| | - Rahul Chakrabarti
- Centre for Eye Research Australia, Department of Ophthalmology, University of Melbourne, Victoria, Australia
| | - Evelyn C O’Neill
- Centre for Eye Research Australia, Department of Ophthalmology, University of Melbourne, Victoria, Australia
| | - Jonathan G Crowston
- Centre for Eye Research Australia, Department of Ophthalmology, University of Melbourne, Victoria, Australia
| | - Ian A Trounce
- Centre for Eye Research Australia, Department of Ophthalmology, University of Melbourne, Victoria, Australia
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Abstract
Glaucoma, a leading cause of blindness worldwide, is characterized by progressive optic nerve damage, usually associated with intraocular pressure. Although the clinical progression of the disease is well defined, the molecular events responsible for glaucoma are currently poorly understood and current therapeutic strategies are not curative. This review summarizes the human genetics and genomic approaches that have shed light on the complex inheritance of glaucoma genes and the potential for gene-based and cellular therapies that this research makes possible.
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Affiliation(s)
- Bao Jian Fan
- Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, Massachusetts, USA
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Abstract
Glaucoma is the leading cause of visual impairment and blindness throughout the world. Primary open angle glaucoma (POAG; MIM 137760) is the main type of glaucoma in most populations, and more than 20 genetic loci for POAG have been reported. Only three causative genes have been identified in these loci, viz. myocilin (MYOC), optineurin (OPTN), and WD repeat domain 36 (WDR36). However, mutations in these genes account for only a small percentage of the patients with POAG. Some of these glaucoma cases have a Mendelian inheritance pattern, and a considerable fraction of the cases result from a large number of variants in several genes each contributing small effects. Glaucoma is considered to be a common disease such as diabetes mellitus, coronary disease, Crohn disease, and several( )common cancers. The main technological approaches used to identify the genes associated with glaucoma are the candidate gene approach, linkage analysis, case-control association study, and genome-wide association study. Association studies have found about 27 genes related to POAG, but the glaucoma-causing effects of these genes need to be investigated in more detail. The current trend is to use case-control association studies or genome-wide association studies to map the genes associated with glaucoma. Such studies are expected to greatly advance our understanding of the genetic basis of glaucoma, and to provide information on the effectiveness of glaucoma therapy. This review gives an overview on the genetic aspects of glaucoma.
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Affiliation(s)
- Nobuo Fuse
- Department of Ophthalmology, Tohoku University Graduate School of Medicine, Sendai, Japan.
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Lee S, Van Bergen NJ, Kong GY, Chrysostomou V, Waugh HS, O'Neill EC, Crowston JG, Trounce IA. Mitochondrial dysfunction in glaucoma and emerging bioenergetic therapies. Exp Eye Res 2010; 93:204-12. [PMID: 20691180 DOI: 10.1016/j.exer.2010.07.015] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2010] [Revised: 07/16/2010] [Accepted: 07/27/2010] [Indexed: 12/22/2022]
Abstract
The similarities between glaucoma and mitochondrial optic neuropathies have driven a growing interest in exploring mitochondrial function in glaucoma. The specific loss of retinal ganglion cells is a common feature of mitochondrial diseases - not only the classic mitochondrial optic neuropathies of Leber's Hereditary Optic Neuropathy and Autosomal Dominant Optic Atrophy - but also occurring together with more severe central nervous system involvement in many other syndromic mitochondrial diseases. The retinal ganglion cell, due to peculiar structural and energetic constraints, appears acutely susceptible to mitochondrial dysfunction. Mitochondrial function is also well known to decline with aging in post-mitotic tissues including neurons. Because age is a risk factor for glaucoma this adds another impetus to investigating mitochondria in this common and heterogeneous neurodegenerative disease. Mitochondrial function may be impaired by either nuclear gene or mitochondrial DNA genetic risk factors, by mechanical stress or chronic hypoperfusion consequent to the commonly raised intraocular pressure in glaucomatous eyes, or by toxic xenobiotic or even light-induced oxidative stress. If primary or secondary mitochondrial dysfunction is further established as contributing to glaucoma pathogenesis, emerging therapies aimed at optimizing mitochondrial function represent potentially exciting new clinical treatments that may slow retinal ganglion cell and vision loss in glaucoma.
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Affiliation(s)
- Shanjean Lee
- Centre for Eye Research Australia, University of Melbourne, Department of Ophthalmology, Royal Victorian Eye and Ear Hospital, 32 Gisborne Street East, Melbourne, Victoria 3002, Australia
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VAV2 and VAV3 as candidate disease genes for spontaneous glaucoma in mice and humans. PLoS One 2010; 5:e9050. [PMID: 20140222 PMCID: PMC2816215 DOI: 10.1371/journal.pone.0009050] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2009] [Accepted: 01/18/2010] [Indexed: 12/22/2022] Open
Abstract
Background Glaucoma is a leading cause of blindness worldwide. Nonetheless, the mechanism of its pathogenesis has not been well-elucidated, particularly at the molecular level, because of insufficient availability of experimental genetic animal models. Methodology/Principal Findings Here we demonstrate that deficiency of Vav2 and Vav3, guanine nucleotides exchange factors for Rho guanosine triphosphatases, leads to an ocular phenotype similar to human glaucoma. Vav2/Vav3-deficient mice, and to a lesser degree Vav2-deficient mice, show early onset of iridocorneal angle changes and elevated intraocular pressure, with subsequent selective loss of retinal ganglion cells and optic nerve head cupping, which are the hallmarks of glaucoma. The expression of Vav2 and Vav3 tissues was demonstrated in the iridocorneal angle and retina in both mouse and human eyes. In addition, a genome-wide association study screening glaucoma susceptibility loci using single nucleotide polymorphisms analysis identified VAV2 and VAV3 as candidates for associated genes in Japanese open-angle glaucoma patients. Conclusions/Significance Vav2/Vav3-deficient mice should serve not only as a useful murine model of spontaneous glaucoma, but may also provide a valuable tool in understanding of the pathogenesis of glaucoma in humans, particularly the determinants of altered aqueous outflow and subsequent elevated intraocular pressure.
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