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Park HYL, Kim JH, Park CK. Different contributions of autophagy to retinal ganglion cell death in the diabetic and glaucomatous retinas. Sci Rep 2018; 8:13321. [PMID: 30190527 PMCID: PMC6127281 DOI: 10.1038/s41598-018-30165-7] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Accepted: 03/19/2018] [Indexed: 12/16/2022] Open
Abstract
Diabetes mellitus and glaucoma are the two major causes of selective retinal ganglion cell (RGC) death. To determine the relationship between autophagy and RGC death, we compared autophagy and the related molecular pathways in diabetic and glaucomatous retinas and examined their effect on RGC survival. Biochemical analysis of microtubule-associated protein light chain 3 (LC3)-II and beclin-1 were observed. To determine the pathways involved in autophagy induction, adenosine monophosphate-activated protein kinase (AMPK) and the mechanistic target of rapamycin (mTOR) were also explored. Beclin-1 and the LC3B-II to LC3B-I ratio significantly elevated at 4 and 8 weeks after glaucoma induction; however, only a slight increase was apparent in the diabetic retina. Significant upregulation of phosphorylated AMPK and downregulation of phosphorylated mTOR was evident in the diabetic retina. After autophagy was inhibited with 3-methyladenine (3-MA), apoptosis of RGCs was significantly increased in the diabetic retinas. However, 3-MA inhibition of autophagy decreased the apoptosis of RGCs in glaucomatous retinas. Therefore, our results suggest that RGC death is differentially regulated by autophagy and that the pathways involved differ depending on the triggering injury.
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Affiliation(s)
- Hae-Young Lopilly Park
- Department of Ophthalmology, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Jie Hyun Kim
- Department of Ophthalmology, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Chan Kee Park
- Department of Ophthalmology, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.
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Hirt J, Porter K, Dixon A, McKinnon S, Liton PB. Contribution of autophagy to ocular hypertension and neurodegeneration in the DBA/2J spontaneous glaucoma mouse model. Cell Death Discov 2018; 4:14. [PMID: 30210817 PMCID: PMC6127277 DOI: 10.1038/s41420-018-0077-y] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Revised: 06/15/2018] [Accepted: 06/22/2018] [Indexed: 01/01/2023] Open
Abstract
Glaucoma is a progressive optic neuropathy characterized by axonal degeneration and retinal ganglion cells loss. Several factors have been postulated to play a role in glaucoma, elevated intraocular pressure (IOP) being the best well-known causative factor. The mechanisms leading to ocular hypertension and glaucoma are still not fully understood. An increasing number of evidence indicates a role of autophagy in the pathophysiological process of ocular hypertension and glaucoma. However, while all of the studies agree that autophagy is induced in RGCs in response to injury, autophagy was found to either protect or promote cell death depending on the experimental model used. In order to gain more insight into both, the role of autophagy in the pathogenesis of glaucoma and the effect of chronic IOP elevation in the autophagy pathway, we have investigated here for the first time autophagy in the iridocorneal angle region, retinal ganglion cell bodies, and ON axons in the spontaneous ocular hypertensive DBA/2J mouse glaucoma model and in the transgenic DBA/2J::GFP-LC3 mice, generated in our laboratory. Our results indicate decreased autophagic flux in the outflow pathway cells in the DBA/2J mice, characterized by increased levels of LC3-II and p62 together with a decrease in the lysosomal marker LAMP1, evaluated by western blot and immunofluorescence. Elevated presence of autophagic vacuoles in the DBA/2J and, in particular, in the DBA/2J::GFP-LC3 mice was also observed. Expression of the GFP-LC3 transgene was associated to higher cumulative IOP in the DBA/2J background. In addition to higher elevation in IOP, DBA/2J::GFP-LC3 were characterized by further RGCs and exacerbated axonal degeneration compared to DBA/2J. This was accompanied by the notable high presence of autophagic figures within degenerating axons. These results strongly suggest overactivation of autophagy as a potential cellular mechanism leading to ON degeneration in the chronic hypertensive DBA/2J mice.
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Affiliation(s)
- Joshua Hirt
- Duke University, Department of Ophthalmology, Durham, NC USA
| | - Kris Porter
- Duke University, Department of Ophthalmology, Durham, NC USA
| | - Angela Dixon
- Duke University, Department of Ophthalmology, Durham, NC USA
| | - Stuart McKinnon
- Duke University, Department of Ophthalmology, Durham, NC USA
| | - Paloma B Liton
- Duke University, Department of Ophthalmology, Durham, NC USA
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Lascaratos G, Chau KY, Zhu H, Gkotsi D, Kamal D, Gout I, Luthert PJ, Schapira AH, Garway-Heath DF. Systemic PTEN-Akt1-mTOR pathway activity in patients with normal tension glaucoma and ocular hypertension: A case series. Mitochondrion 2017; 36:96-102. [DOI: 10.1016/j.mito.2017.05.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Revised: 03/07/2017] [Accepted: 05/08/2017] [Indexed: 12/30/2022]
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Crooke A, Huete-Toral F, Colligris B, Pintor J. The role and therapeutic potential of melatonin in age-related ocular diseases. J Pineal Res 2017; 63. [PMID: 28658514 DOI: 10.1111/jpi.12430] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Accepted: 06/23/2017] [Indexed: 12/20/2022]
Abstract
The eye is continuously exposed to solar UV radiation and pollutants, making it prone to oxidative attacks. In fact, oxidative damage is a major cause of age-related ocular diseases including cataract, glaucoma, age-related macular degeneration, and diabetic retinopathy. As the nature of lens cells, trabecular meshwork cells, retinal ganglion cells, retinal pigment epithelial cells, and photoreceptors is postmitotic, autophagy plays a critical role in their cellular homeostasis. In age-related ocular diseases, this process is impaired, and thus, oxidative damage becomes irreversible. Other conditions such as low-grade chronic inflammation and angiogenesis also contribute to the development of retinal diseases (glaucoma, age-related macular degeneration and diabetic retinopathy). As melatonin is known to have remarkable qualities such as antioxidant/antinitridergic, mitochondrial protector, autophagy modulator, anti-inflammatory, and anti-angiogenic, it can represent a powerful tool to counteract all these diseases. The present review analyzes the role and therapeutic potential of melatonin in age-related ocular diseases, focusing on nitro-oxidative stress, autophagy, inflammation, and angiogenesis mechanisms.
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Affiliation(s)
- Almudena Crooke
- Department of Biochemistry and Molecular Biology IV, Group Ocupharm, Faculty of Optics and Optometry, Universidad Complutense de Madrid, Madrid, Spain
| | - Fernando Huete-Toral
- Department of Biochemistry and Molecular Biology IV, Group Ocupharm, Faculty of Optics and Optometry, Universidad Complutense de Madrid, Madrid, Spain
| | - Basilio Colligris
- Department of Biochemistry and Molecular Biology IV, Group Ocupharm, Faculty of Optics and Optometry, Universidad Complutense de Madrid, Madrid, Spain
| | - Jesús Pintor
- Department of Biochemistry and Molecular Biology IV, Group Ocupharm, Faculty of Optics and Optometry, Universidad Complutense de Madrid, Madrid, Spain
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Williams PA, Marsh-Armstrong N, Howell GR. Neuroinflammation in glaucoma: A new opportunity. Exp Eye Res 2017; 157:20-27. [PMID: 28242160 PMCID: PMC5497582 DOI: 10.1016/j.exer.2017.02.014] [Citation(s) in RCA: 165] [Impact Index Per Article: 23.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Revised: 02/16/2017] [Accepted: 02/23/2017] [Indexed: 10/20/2022]
Abstract
Mounting evidence suggests neuroinflammation is a key process in glaucoma, yet the precise roles are not known. Understanding these complex processes, which may also be a key in other common neurodegenerations such as Alzheimer's disease, will lead to targeted therapeutics for a disease that affects as many as 80 million people worldwide. Here, we define neuroinflammation as any immune-relevant response by a variety of cell types including astrocytes, microglia, and peripherally derived cells occurring in the optic nerve head and/or retina. In this review article, we first discuss clinical evidence for neuroinflammation in glaucoma and define neuroinflammation in glaucoma. We then review the inflammatory pathways that have been associated with glaucoma. Finally, we set out key research directions that we believe will greatly advance our understanding of the role of neuroinflammation in glaucoma. This review arose from a discussion of neuroinflammation in glaucoma at the 2015 meeting of The Lasker/IRRF Initiative for Innovation in Vision Science. This manuscript sets out to summarize one of these sessions; "Inflammation and Glaucomatous Neurodegeneration", as well as to review the current state of the literature surrounding neuroinflammation in glaucoma.
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Affiliation(s)
| | - Nick Marsh-Armstrong
- The Solomon H. Snyder Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, MD, USA; Hugo W. Moser Research Institute, Kennedy Krieger Institute, Baltimore, MD, USA
| | - Gareth R Howell
- The Jackson Laboratory, Bar Harbor, ME, USA; Graduate Program of Genetics, Sackler School of Graduate Biomedical Sciences, Tufts University, Boston, MA, USA.
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Davis BM, Crawley L, Pahlitzsch M, Javaid F, Cordeiro MF. Glaucoma: the retina and beyond. Acta Neuropathol 2016; 132:807-826. [PMID: 27544758 PMCID: PMC5106492 DOI: 10.1007/s00401-016-1609-2] [Citation(s) in RCA: 159] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Revised: 08/02/2016] [Accepted: 08/10/2016] [Indexed: 12/31/2022]
Abstract
Over 60 million people worldwide are diagnosed with glaucomatous optic neuropathy, which is estimated to be responsible for 8.4 million cases of irreversible blindness globally. Glaucoma is associated with characteristic damage to the optic nerve and patterns of visual field loss which principally involves the loss of retinal ganglion cells (RGCs). At present, intraocular pressure (IOP) presents the only modifiable risk factor for glaucoma, although RGC and vision loss can continue in patients despite well-controlled IOP. This, coupled with the present inability to diagnose glaucoma until relatively late in the disease process, has led to intense investigations towards the development of novel techniques for the early diagnosis of disease. This review outlines our current understanding of the potential mechanisms underlying RGC and axonal loss in glaucoma. Similarities between glaucoma and other neurodegenerative diseases of the central nervous system are drawn before an overview of recent developments in techniques for monitoring RGC health is provided, including recent progress towards the development of RGC specific contrast agents. The review concludes by discussing techniques to assess glaucomatous changes in the brain using MRI and the clinical relevance of glaucomatous-associated changes in the visual centres of the brain.
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Affiliation(s)
| | - Laura Crawley
- Western Eye Hospital, Imperial College Healthcare NHS Trust, 153-173 Marylebone Road, London, UK
| | | | - Fatimah Javaid
- UCL Institute of Ophthalmology, 11-43 Bath Street, London, UK
| | - Maria Francesca Cordeiro
- UCL Institute of Ophthalmology, 11-43 Bath Street, London, UK.
- Western Eye Hospital, Imperial College Healthcare NHS Trust, 153-173 Marylebone Road, London, UK.
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58
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Dulull NK, Thrimawithana TR, Kwa FAA. Mimicking the ocular environment for the study of inflammatory posterior eye disorders. Drug Discov Today 2016; 22:440-446. [PMID: 27871941 DOI: 10.1016/j.drudis.2016.11.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Revised: 10/04/2016] [Accepted: 11/14/2016] [Indexed: 01/07/2023]
Abstract
The common inflammatory posterior eye disorders, age-related degeneration and glaucoma often lead to irreversible vision loss. Current treatments do not target early stages or prevent disease progression. Consequently, the identification of biomarkers or early disease models that can accurately mimic the pathological processes involved is essential. Although none of the existing models can recapitulate all pathological aspects of these disorders, these models have revealed new therapeutic targets. Efforts to accurately phenotype eye disorders at various disease stages are warranted to generate a 'super' model that can replicate the microenvironment of the eye and associated pathological hallmarks effectively.
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Affiliation(s)
- Nabeela K Dulull
- Discipline of Laboratory Medicine, School of Health and Biomedical Sciences, RMIT University, Bundoora, VIC 3083, Australia
| | - Thilini R Thrimawithana
- Discipline of Pharmacy, School of Health and Biomedical Sciences, RMIT University, Bundoora, VIC 3083, Australia
| | - Faith A A Kwa
- Discipline of Laboratory Medicine, School of Health and Biomedical Sciences, RMIT University, Bundoora, VIC 3083, Australia.
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Nucci C, Russo R, Martucci A, Giannini C, Garaci F, Floris R, Bagetta G, Morrone LA. New strategies for neuroprotection in glaucoma, a disease that affects the central nervous system. Eur J Pharmacol 2016; 787:119-26. [DOI: 10.1016/j.ejphar.2016.04.030] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2015] [Revised: 03/23/2016] [Accepted: 04/14/2016] [Indexed: 01/30/2023]
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Boya P, Esteban-Martínez L, Serrano-Puebla A, Gómez-Sintes R, Villarejo-Zori B. Autophagy in the eye: Development, degeneration, and aging. Prog Retin Eye Res 2016; 55:206-245. [PMID: 27566190 DOI: 10.1016/j.preteyeres.2016.08.001] [Citation(s) in RCA: 129] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2016] [Revised: 08/15/2016] [Accepted: 08/18/2016] [Indexed: 02/06/2023]
Abstract
Autophagy is a catabolic pathway that promotes the degradation and recycling of cellular components. Proteins, lipids, and even whole organelles are engulfed in autophagosomes and delivered to the lysosome for elimination. In response to stress, autophagy mediates the degradation of cell components, which are recycled to generate the nutrients and building blocks required to sustain cellular homeostasis. Moreover, it plays an important role in cellular quality control, particularly in neurons, in which the total burden of altered proteins and damaged organelles cannot be reduced by redistribution to daughter cells through cell division. Research has only begun to examine the role of autophagy in the visual system. The retina, a light-sensitive tissue, detects and transmits electrical impulses through the optic nerve to the visual cortex in the brain. Both the retina and the eye are exposed to a variety of environmental insults and stressors, including genetic mutations and age-associated alterations that impair their function. Here, we review the main studies that have sought to explain autophagy's importance in visual function. We describe the role of autophagy in retinal development and cell differentiation, and discuss the implications of autophagy dysregulation both in physiological aging and in important diseases such as age-associated macular degeneration and glaucoma. We also address the putative role of autophagy in promoting photoreceptor survival and discuss how selective autophagy could provide alternative means of protecting retinal cells. The findings reviewed here underscore the important role of autophagy in maintaining proper retinal function and highlight novel therapeutic approaches for blindness and other diseases of the eye.
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Affiliation(s)
- Patricia Boya
- Autophagy Lab, Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, 28040, Madrid, Spain.
| | - Lorena Esteban-Martínez
- Autophagy Lab, Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, 28040, Madrid, Spain
| | - Ana Serrano-Puebla
- Autophagy Lab, Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, 28040, Madrid, Spain
| | - Raquel Gómez-Sintes
- Autophagy Lab, Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, 28040, Madrid, Spain
| | - Beatriz Villarejo-Zori
- Autophagy Lab, Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, 28040, Madrid, Spain
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Dang Y, Mu Y, Wang K, Xu K, Yang J, Zhu Y, Luo B. Papaverine inhibits lipopolysaccharide-induced microglial activation by suppressing NF-κB signaling pathway. DRUG DESIGN DEVELOPMENT AND THERAPY 2016; 10:851-9. [PMID: 27013863 PMCID: PMC4777259 DOI: 10.2147/dddt.s97380] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Objective To investigate the effects of papaverine (PAP) on lipopolysaccharide (LPS)-induced microglial activation and its possible mechanisms. Materials and methods BV2 microglial cells were first pretreated with PAP (0, 0.4, 2, 10, and 50 μg/mL) and then received LPS stimulation. Transcription and production of proinflammatory factors (IL1β, TNFα, iNOS, and COX-2) were used to evaluate microglial activation. The transcriptional changes undergone by M1/M2a/M2b markers were used to evaluate phenotype transformation of BV2 cells. Immunofluorescent staining and Western blot were used to detect the location and expression of P65 and p-IKK in the presence or absence of PAP pretreatment. Results Pretreatment with PAP significantly inhibited the expression of IL1β and TNFα, and suppressed the transcription of M1/M2b markers Il1rn, Socs3, Nos2 and Ptgs2, but upregulated the transcription of M2a markers (Arg1 and Mrc1) in a dose-dependent manner. In addition, PAP pretreatment significantly decreased the expression of p-IKK and inhibited the nuclear translocation of P65 after LPS stimulation. Conclusion PAP not only suppressed the LPS-induced microglial activity by inhibiting transcription/production of proinflammatory factors, but also promoted the transformation of activated BV2 cells from cytotoxic phenotypes (M1/M2b) to a neuroprotective phenotype (M2a). These effects were probably mediated by NF-κB signaling pathway. Thus, it would be a promising candidate for the treatment of neurodegenerative diseases.
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Affiliation(s)
- Yalong Dang
- Department of Ophthalmology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, People's Republic of China
| | - Yalin Mu
- Department of Ophthalmology, Yellow-River Hospital, Sanmenxia City, People's Republic of China
| | - Kun Wang
- Clinical Laboratory, Yellow-River Hospital, Sanmenxia City, People's Republic of China
| | - Ke Xu
- Department of Ophthalmology, Yellow-River Hospital, Sanmenxia City, People's Republic of China
| | - Jing Yang
- Department of Ophthalmology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, People's Republic of China
| | - Yu Zhu
- Department of Ophthalmology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, People's Republic of China
| | - Bin Luo
- Department of Ophthalmology, Yellow-River Hospital, Sanmenxia City, People's Republic of China; Clinical Laboratory, Yellow-River Hospital, Sanmenxia City, People's Republic of China
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Autophagy dysregulation and the fate of retinal ganglion cells in glaucomatous optic neuropathy. PROGRESS IN BRAIN RESEARCH 2015; 220:87-105. [PMID: 26497786 DOI: 10.1016/bs.pbr.2015.04.009] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Glaucoma is a neurodegenerative disease caused by the progressive apoptotic death of retinal ganglion cells (RGCs). The mechanisms leading to the RGC loss are still unknown but it is now clear that, besides elevated intraocular pressure (IOP), which is considered the main risk factor, other IOP-independent determinants are responsible for the development of the optic neuropathy. Autophagy is a highly conserved catabolic pathway by which cellular components are degraded through the lysosomes. Dysfunctional autophagic pathway has been associated with several neuropathological conditions and a considerable number of studies have proved autophagy as a potential target for pharmacological modulation to achieve neuroprotection. Here, we review the current literature bridging the degeneration of RGCs to alterations of the autophagic pathway; we also discuss the possible role of autophagy in the pathogenesis and progression of glaucoma in view of the future application of autophagy modulators for glaucoma therapy.
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63
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Wang Y, Huang C, Zhang H, Wu R. Autophagy in glaucoma: Crosstalk with apoptosis and its implications. Brain Res Bull 2015; 117:1-9. [PMID: 26073842 DOI: 10.1016/j.brainresbull.2015.06.001] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2014] [Revised: 05/05/2015] [Accepted: 06/04/2015] [Indexed: 01/07/2023]
Abstract
Glaucoma is characterized by elevated intraocular pressure that causes progressive loss of retinal ganglion cells (RGCs). Autophagy is a lysosomal degradative process that updates the cellular components and plays an important role in cellular homeostasis. Recent studies have shown that autophagy is involved in the pathophysiological process of glaucoma. The role played by autophagy in glaucoma is complex, and conflicting evidence shows that autophagy promotes both RGC survival and death. The understanding of the major pattern of RGC loss and the crosstalk between autophagy and apoptosis remains limited in glaucoma. This review focuses on the relationship between autophagy and glaucoma, particularly on the influence of autophagy on apoptosis in glaucoma. Further research on autophagy in glaucoma may provide a novel understanding of the glaucoma pathology and novel treatment targets for glaucoma in the future.
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Affiliation(s)
- Yao Wang
- Eye Institute and Affiliated Xiamen Eye Center, Xiamen University, Fujian Provincial Key Laboratory of Ophthalmology and Visual Science, Xiamen, Fujian 361102, China; Department of Ophthalmology, First Hospital of Xi'an, Shaanxi Institute of Ophthalmology, Shaanxi Provincial Key Lab of Ophthalmology, Xi'an, Shaanxi 710002, China
| | - Changquan Huang
- Eye Institute and Affiliated Xiamen Eye Center, Xiamen University, Fujian Provincial Key Laboratory of Ophthalmology and Visual Science, Xiamen, Fujian 361102, China
| | - Hongbing Zhang
- Department of Ophthalmology, First Hospital of Xi'an, Shaanxi Institute of Ophthalmology, Shaanxi Provincial Key Lab of Ophthalmology, Xi'an, Shaanxi 710002, China
| | - Renyi Wu
- Eye Institute and Affiliated Xiamen Eye Center, Xiamen University, Fujian Provincial Key Laboratory of Ophthalmology and Visual Science, Xiamen, Fujian 361102, China.
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Autophagy in axonal degeneration in glaucomatous optic neuropathy. Prog Retin Eye Res 2015; 47:1-18. [PMID: 25816798 DOI: 10.1016/j.preteyeres.2015.03.002] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Revised: 03/14/2015] [Accepted: 03/19/2015] [Indexed: 01/07/2023]
Abstract
The role of autophagy in retinal ganglion cell (RGC) death is still controversial. Several studies focused on RGC body death, although the axonal degeneration pathway in the optic nerve has not been well documented in spite of evidence that the mechanisms of degeneration of neuronal cell bodies and their axons differ. Axonal degeneration of RGCs is a hallmark of glaucoma, and a pattern of localized retinal nerve fiber layer defects in glaucoma patients indicates that axonal degeneration may precede RGC body death in this condition. As models of preceding axonal degeneration, both the tumor necrosis factor (TNF) injection model and hypertensive glaucoma model may be useful in understanding the mechanism of axonal degeneration of RGCs, and the concept of axonal protection can be an attractive approach to the prevention of neurodegenerative optic nerve disease. Since mitochondria play crucial roles in glaucomatous optic neuropathy and can themselves serve as a part of the autophagosome, it seems that mitochondrial function may alter autophagy machinery. Like other neurodegenerative diseases, optic nerve degeneration may exhibit autophagic flux impairment resulting from elevated intraocular pressure, TNF, traumatic injury, ischemia, oxidative stress, and aging. As a model of aging, we used senescence-accelerated mice to provide new insights. In this review, we attempt to describe the relationship between autophagy and recently reported noteworthy factors including Nmnat, ROCK, and SIRT1 in the degeneration of RGCs and their axons and propose possible mechanisms of axonal protection via modulation of autophagy machinery.
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65
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Song W, Huang P, Zhang C. Neuroprotective therapies for glaucoma. DRUG DESIGN DEVELOPMENT AND THERAPY 2015; 9:1469-79. [PMID: 25792807 PMCID: PMC4362661 DOI: 10.2147/dddt.s80594] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Glaucoma is the second leading cause for blindness worldwide. It is mainly caused by glaucomatous optic neuropathy (GON) characterized by retinal ganglion cell loss, which leads to visual field defect and blindness. Up to now, the main purpose of antiglaucomatous therapies has been to lower intraocular pressure (IOP) through surgeries and medications. However, it has been found that progressive GON is still present in some patients with effective IOP decrease. Therefore, risk factors other than IOP elevation, like neurotrophin deprivation and excitotoxicity, contribute to progressive GON. Novel approaches of neuroprotection may be more effective for preserving the function of the optic nerve.
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Affiliation(s)
- Wei Song
- Department of Ophthalmology, Peking University Third Hospital, Beijing, People's Republic of China
| | - Ping Huang
- Department of Ophthalmology, Peking University Third Hospital, Beijing, People's Republic of China
| | - Chun Zhang
- Department of Ophthalmology, Peking University Third Hospital, Beijing, People's Republic of China
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Cholkar K, Trinh HM, Pal D, Mitra AK. Discovery of novel inhibitors for the treatment of glaucoma. Expert Opin Drug Discov 2015; 10:293-313. [PMID: 25575654 DOI: 10.1517/17460441.2015.1000857] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
INTRODUCTION Glaucoma is a neurodegenerative disease with heterogeneous causes that result in retinal ganglionic cell (RGC) death. The discovery of ocular antihypertensives has shifted glaucoma therapy, largely, from surgery to medical intervention. Indeed, several intraocular pressure (IOP)-lowering drugs, with different mechanisms of action and RGC protective property, have been developed. AREAS COVERED In this review, the authors discuss the main new class of kinase inhibitors used as glaucoma treatments, which lower IOP by enhancing drainage and/or lowering production of aqueous humor. The authors include novel inhibitors under preclinical evaluation and investigation for their anti-glaucoma treatment. Additionally, the authors look at treatments that are in clinics now and which may be available in the near future. EXPERT OPINION Treatment of glaucoma remains challenging because the exact cause is yet to be delineated. Neuroprotection to the optic nerve head is undisputable. The novel Rho-associated kinase inhibitors have the capacity to lower IOP and provide optic nerve and RGC protection. In particular, the S-isomer of roscovitine has the capacity to lower IOP and provide neuroprotection. Combinations of selected drugs, which can provide maximal and sustained IOP-lowering effects as well as neuroprotection, are paramount to the prevention of glaucoma progression. In the near future, microRNA intervention may be considered as a potential therapeutic target.
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Affiliation(s)
- Kishore Cholkar
- University of Missouri-Kansas City, School of Pharmacy, Division of Pharmaceutical Sciences , 5258 Health Science Building, 2464 Charlotte Street, Kansas City, MO 64108-2718 , USA +1 816 235 1615 ; +1 816 235 5779 ;
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