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Wang XL, Gao YX, Yuan QZ, Zhang M. NLRP3 and autophagy in retinal ganglion cell inflammation in age-related macular degeneration: potential therapeutic implications. Int J Ophthalmol 2024; 17:1531-1544. [PMID: 39156786 PMCID: PMC11286452 DOI: 10.18240/ijo.2024.08.20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Accepted: 04/22/2024] [Indexed: 08/20/2024] Open
Abstract
Retinal degenerative diseases were a large group of diseases characterized by the primary death of retinal ganglion cells (RGCs). Recent studies had shown an interaction between autophagy and nucleotide-binding oligomerization domain-like receptor 3 (NLRP3) inflammasomes, which may affect RGCs in retinal degenerative diseases. The NLRP3 inflammasome was a protein complex that, upon activation, produces caspase-1, mediating the apoptosis of retinal cells and promoting the occurrence and development of retinal degenerative diseases. Upregulated autophagy could inhibit NLRP3 inflammasome activation, while inhibited autophagy can promote NLRP3 inflammasome activation, which leaded to the accelerated emergence of drusen and lipofuscin deposition under the neurosensory retina. The activated NLRP3 inflammasome could further inhibit autophagy, thus forming a vicious cycle that accelerated the damage and death of RGCs. This review discussed the relationship between NLRP3 inflammasome and autophagy and its effects on RGCs in age-related macular degeneration, providing a new perspective and direction for the treatment of retinal diseases.
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Affiliation(s)
- Xiao-Li Wang
- Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu 610041, Sichuan Province, China
| | - Yun-Xia Gao
- Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu 610041, Sichuan Province, China
| | - Qiong-Zhen Yuan
- Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu 610041, Sichuan Province, China
| | - Ming Zhang
- Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu 610041, Sichuan Province, China
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2
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Zhang Z, Liang F, Chang J, Shan X, Yin Z, Wang L, Li S. Autophagy in dry AMD: A promising therapeutic strategy for retinal pigment epithelial cell damage. Exp Eye Res 2024; 242:109889. [PMID: 38593971 DOI: 10.1016/j.exer.2024.109889] [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: 11/24/2023] [Revised: 04/04/2024] [Accepted: 04/05/2024] [Indexed: 04/11/2024]
Abstract
Dry age-related macular degeneration (AMD) is a prevalent clinical condition that leads to permanent damage to central vision and poses a significant threat to patients' visual health. Although the pathogenesis of dry AMD remains unclear, there is consensus on the role of retinal pigment epithelium (RPE) damage. Oxidative stress and chronic inflammation are major contributors to RPE cell damage, and the NOD-like receptor thermoprotein structural domain-associated protein 3 (NLRP3) inflammasome mediates the inflammatory response leading to apoptosis in RPE cells. Furthermore, lipofuscin accumulation results in oxidative stress, NLRP3 activation, and the development of vitelliform lesions, a hallmark of dry AMD, all of which may contribute to RPE dysfunction. The process of autophagy, involving the encapsulation, recognition, and transport of accumulated proteins and dead cells to the lysosome for degradation, is recognized as a significant pathway for cellular self-protection and homeostasis maintenance. Recently, RPE cell autophagy has been discovered to be closely linked to the development of macular degeneration, positioning autophagy as a cutting-edge research area in the realm of dry AMD. In this review, we present an overview of how lipofuscin, oxidative stress, and the NLRP3 inflammasome damage the RPE through their respective causal mechanisms. We summarized the connection between autophagy, oxidative stress, and NLRP3 inflammatory cytokines. Our findings suggest that targeting autophagy improves RPE function and sustains visual health, offering new perspectives for understanding the pathogenesis and clinical management of dry AMD.
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Affiliation(s)
- Zhao Zhang
- Tianjin University of Chinese Medicine, Tianjin, 300193, China; The First Affiliated Hospital of Tianjin University of Traditional Chinese Medicine, National Clinical Research Center of Traditional Chinese Medicine and Acupuncture and Moxibustion, Tianjin, 300193, China
| | - Fengming Liang
- The First Affiliated Hospital of Tianjin University of Traditional Chinese Medicine, National Clinical Research Center of Traditional Chinese Medicine and Acupuncture and Moxibustion, Tianjin, 300193, China.
| | - Jun Chang
- Tianjin University of Chinese Medicine, Tianjin, 300193, China; The First Affiliated Hospital of Tianjin University of Traditional Chinese Medicine, National Clinical Research Center of Traditional Chinese Medicine and Acupuncture and Moxibustion, Tianjin, 300193, China
| | - Xiaoqian Shan
- Tianjin University of Chinese Medicine, Tianjin, 300193, China; The First Affiliated Hospital of Tianjin University of Traditional Chinese Medicine, National Clinical Research Center of Traditional Chinese Medicine and Acupuncture and Moxibustion, Tianjin, 300193, China
| | - Zhixian Yin
- Hebei University of Technology, School of Electronics and Information Engineering, Tianjin, 300401, China
| | - Li Wang
- The First Affiliated Hospital of Tianjin University of Traditional Chinese Medicine, National Clinical Research Center of Traditional Chinese Medicine and Acupuncture and Moxibustion, Tianjin, 300193, China
| | - Shujiao Li
- Eye Hospital, China Academy of Chinese Medical Sciences, Beijing, 100040, China
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Chu L, Bi C, Wang C, Zhou H. The Relationship between Complements and Age-Related Macular Degeneration and Its Pathogenesis. J Ophthalmol 2024; 2024:6416773. [PMID: 38205100 PMCID: PMC10776198 DOI: 10.1155/2024/6416773] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 06/08/2023] [Accepted: 12/23/2023] [Indexed: 01/12/2024] Open
Abstract
Age-related macular degeneration is a retinal disease that causes permanent loss of central vision in people over the age of 65. Its pathogenesis may be related to mitochondrial dysfunction, inflammation, apoptosis, autophagy, complement, intestinal flora, and lipid disorders. In addition, the patient's genes, age, gender, cardiovascular disease, unhealthy diet, and living habits may also be risk factors for this disease. Complement proteins are widely distributed in serum and tissue fluid. In the early 21st century, a connection was found between the complement cascade and age-related macular degeneration. However, little is known about the effect of complement factors on the pathogenesis of age-related macular degeneration. This article reviews the factors associated with age-related macular degeneration, the relationship between each factor and complement, the related functions, and variants and provides new ideas for the treatment of this disease.
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Affiliation(s)
- Liyuan Chu
- Department of Ophthalmology, China–Japan Union Hospital of Jilin University, Changchun, China
| | - Chaoran Bi
- College of Traditional Chinese Medicine, Hainan Medical University, Haikou, Hainan, China
| | - Caiming Wang
- Department of Ophthalmology, China–Japan Union Hospital of Jilin University, Changchun, China
| | - Hongyan Zhou
- Department of Ophthalmology, China–Japan Union Hospital of Jilin University, Changchun, China
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Zhang Q, Autterson G, Miller JML. Improved Lipofuscin Models and Quantification of Outer Segment Phagocytosis Capacity in Highly Polarized Human Retinal Pigment Epithelial Cultures. J Vis Exp 2023:10.3791/65242. [PMID: 37125790 PMCID: PMC10306344 DOI: 10.3791/65242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2023] Open
Abstract
The daily phagocytosis of photoreceptor outer segments by the retinal pigment epithelium (RPE) contributes to the accumulation of an intracellular aging pigment termed lipofuscin. The toxicity of lipofuscin is well established in Stargardt's disease, the most common inherited retinal degeneration, but is more controversial in age-related macular degeneration (AMD), the leading cause of irreversible blindness in the developed world. Determining lipofuscin toxicity in humans has been difficult, and animal models of Stargardt's have limited toxicity. Thus, in vitro models that mimic human RPE in vivo are needed to better understand lipofuscin generation, clearance, and toxicity. The majority of cell culture lipofuscin models to date have been in cell lines or have involved feeding RPE a single component of the complex lipofuscin mixture rather than fragments/tips of the entire photoreceptor outer segment, which generates a more complete and physiologic lipofuscin model. Described here is a method to induce the accumulation of lipofuscin-like material (termed undigestible autofluorescence material, or UAM) in highly differentiated primary human pre-natal RPE (hfRPE) and induced pluripotent stem cell (iPSC) derived RPE. UAM accumulated in cultures by repeated feedings of ultraviolet light-treated OS fragments taken up by the RPE via phagocytosis. The key ways that UAM approximates and differs from lipofuscin in vivo are also discussed. Accompanying this model of lipofuscin-like accumulation, imaging methods to distinguish the broad autofluorescence spectrum of UAM granules from concurrent antibody staining are introduced. Finally, to assess the impact of UAM on RPE phagocytosis capacity, a new method for quantifying outer segment fragment/tips uptake and breakdown has been introduced. Termed "Total Consumptive Capacity", this method overcomes potential misinterpretations of RPE phagocytosis capacity inherent in classic outer segment "pulse-chase" assays. The models and techniques introduced here can be used to study lipofuscin generation and clearance pathways and putative toxicity.
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Affiliation(s)
- Qitao Zhang
- Kellogg Eye Center, University of Michigan, Ann Arbor
| | | | - Jason M L Miller
- Kellogg Eye Center, University of Michigan, Ann Arbor; Cellular and Molecular Biology Program, University of Michigan, Ann Arbor;
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Young Shin C, Lee S, Lan Jin H, Fei X, Won Kang S, Seo SY, Won Jeong K. A small molecule compound that inhibits blue light-induced retinal damage via activation of autophagy. Biochem Pharmacol 2023; 211:115534. [PMID: 37019186 DOI: 10.1016/j.bcp.2023.115534] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Revised: 03/24/2023] [Accepted: 03/28/2023] [Indexed: 04/05/2023]
Abstract
Dry age-related macular degeneration (AMD) is a type of disease that causes visual impairment due to changes in the macula located in the center of the retina. The accumulation of drusen under the retina is also a characteristic of dry AMD. In this study, we identified a compound (JS-017) that can potentially degrade N-retinylidene-N-retinylethanolamine (A2E), one of the components of lipofuscin, using fluorescence-based screening, which measures A2E degradation in human retinal pigment epithelial cells. JS-017 effectively degraded A2E in ARPE-19 cells and consequently suppressed the activation of the NF-κB signaling pathway and expression of inflammatory and apoptosis genes induced by blue light (BL). Mechanistically, JS-017 induced LC3-II formation and improved autophagic flux in ARPE-19 cells. Additionally, the A2E degradation activity of JS-017 was found to be decreased in autophagy-related 5 protein-depleted ARPE-19 cells, suggesting that autophagy was required for A2E degradation mediated by JS-017. Finally, JS-017 exhibited an improvement in BL-induced retinal damage measured through fundus examination in an in vivo retinal degeneration mouse model. The thickness of the outer nuclear layer and inner/external segments, which was decreased upon exposure to BL irradiation, was also restored upon JS-017 treatment. Altogether, we demonstrated that JS-017 protected human retinal pigment epithelium (RPE) cells from A2E and BL-induced damage by degrading A2E via the activation of autophagy. The results suggest the feasibility of a novel A2E-degrading small molecule as a therapeutic agent for retinal degenerative diseases.
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Protective effects of Panax ginseng berry extract on blue light-induced retinal damage in ARPE-19 cells and mouse retina. J Ginseng Res 2023; 47:65-73. [PMID: 36644394 PMCID: PMC9834005 DOI: 10.1016/j.jgr.2022.04.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 03/30/2022] [Accepted: 04/11/2022] [Indexed: 01/18/2023] Open
Abstract
Background Age-related macular degeneration (AMD) is a significant visual disease that induces impaired vision and irreversible blindness in the elderly. However, the effects of ginseng berry extract (GBE) on the retina have not been studied. Therefore, this study aimed to investigate the protective effects of GBE on blue light (BL)-induced retinal damage and elucidate its underlying mechanisms in human retinal pigment epithelial cells (ARPE-19 cells) and Balb/c retina. Methods To investigate the effects and underlying mechanisms of GBE on retinal damage in vitro, we performed cell viability assay, pre-and post-treatment of sample, reactive oxygen species (ROS) assay, quantitative real-time PCR (qRT-PCR), and western immunoblotting using A2E-laden ARPE-19 cells with BL exposure. In addition, Balb/c mice were irradiated with BL to induce retinal degeneration and orally administrated with GBE (50, 100, 200 mg/kg). Using the harvested retina, we performed histological analysis (thickness of retinal layers), qRT-PCR, and western immunoblotting to elucidate the effects and mechanisms of GBE against retinal damage in vivo. Results GBE significantly inhibited BL-induced cell damage in ARPE-19 cells by activating the SIRT1/PGC-1α pathway, regulating NF-kB translocation, caspase 3 activation, PARP cleavage, expressions of apoptosis-related factors (BAX/BCL-2, LC3-Ⅱ, and p62), and ROS production. Furthermore, GBE prevented BL-induced retinal degeneration by restoring the thickness of retinal layers and suppressed inflammation and apoptosis via regulation of NF-kB and SIRT1/PGC-1α pathway, cleavage of caspase 3 and PARP, and expressions of apoptosis-related factors in vivo. Conclusions GBE could be a potential agent to prevent dry AMD and progression to wet AMD.
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Weinberg J, Gaur M, Swaroop A, Taylor A. Proteostasis in aging-associated ocular disease. Mol Aspects Med 2022; 88:101157. [PMID: 36459837 PMCID: PMC9742340 DOI: 10.1016/j.mam.2022.101157] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Accepted: 11/15/2022] [Indexed: 11/30/2022]
Abstract
Vision impairment has devastating consequences for the quality of human life. The cells and tissues associated with the visual process must function throughout one's life span and maintain homeostasis despite exposure to a variety of insults. Maintenance of the proteome is termed proteostasis, and is vital for normal cellular functions, especially at an advanced age. Here we describe basic aspects of proteostasis, from protein synthesis and folding to degradation, and discuss the current status of the field with a particular focus on major age-related eye diseases: age-related macular degeneration, cataract, and glaucoma. Our intent is to allow vision scientists to determine where and how to harness the proteostatic machinery for extending functional homeostasis in the aging retina, lens, and trabecular meshwork. Several common themes have emerged despite these tissues having vastly different metabolisms. Continued exposure to insults, including chronic stress with advancing age, increases proteostatic burden and reduces the fidelity of the degradation machineries including the ubiquitin-proteasome and the autophagy-lysosome systems that recognize and remove damaged proteins. This "double jeopardy" results in an exponential accumulation of cytotoxic proteins with advancing age. We conclude with a discussion of the challenges in maintaining an appropriate balance of protein synthesis and degradation pathways, and suggest that harnessing proteostatic capacities should provide new opportunities to design interventions for attenuating age-related eye diseases before they limit sight.
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Affiliation(s)
- Jasper Weinberg
- Laboratory for Nutrition and Vision Research, USDA Human Nutrition Research Center on Aging, Tufts University, Boston, MA, 02111, USA
| | - Mohita Gaur
- Neurobiology, Neurodegeneration & Repair Laboratory, National Eye Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Anand Swaroop
- Neurobiology, Neurodegeneration & Repair Laboratory, National Eye Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Allen Taylor
- Laboratory for Nutrition and Vision Research, USDA Human Nutrition Research Center on Aging, Tufts University, Boston, MA, 02111, USA.
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NMDA Receptor Antagonists Degrade Lipofuscin via Autophagy in Human Retinal Pigment Epithelial Cells. MEDICINA (KAUNAS, LITHUANIA) 2022; 58:medicina58081129. [PMID: 36013596 PMCID: PMC9415004 DOI: 10.3390/medicina58081129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Revised: 08/11/2022] [Accepted: 08/17/2022] [Indexed: 11/17/2022]
Abstract
Background and Objectives: Age-related macular degeneration is a slow-progressing disease in which lipofuscin accumulates in the retina, causing inflammation and apoptosis of retinal pigment epithelial (RPE) cells. This study aimed to identify N-methyl-D-aspartate (NMDA) signaling as a novel mechanism for scavenging N-retinylidene-N-retinylethanolamine (A2E), a component of ocular lipofuscin, in human RPE cells. Materials and Methods: A2E degradation assays were performed in ARPE-19 cells using fluorescently labeled A2E. The autophagic activity in ARPE-19 cells was measured upon blue light (BL) exposure, after A2E treatment. Autophagy flux was determined by measuring LC3-II formation using immunoblotting and confocal microscopy. To determine whether autophagy via the NMDA receptor is involved in A2E clearance, ATG5-deficient cells were used. Results: Ro 25-6981, an NR2B-selective NMDA receptor antagonist, effectively cleared A2E. Ro 25-6981 reduced A2E accumulation in the lysosomes of ARPE-19 cells at sub-cytotoxic concentrations, while increasing the formation of LC3-II and decreasing p62 protein levels in a concentration-dependent manner. The autophagic flux monitored by RFP-GFP-LC3 and bafilomycin A1 assays was significantly increased by Ro 25-6981. A2E clearance by Ro 25-6981 was abolished in ATG5-depleted ARPE-19 cells, suggesting that A2E degradation by Ro 25-6981 was mediated by autophagy. Furthermore, treatment with other NMDA receptor antagonists, CP-101,606 and AZD6765, showed similar effects on autophagy activation and A2E degradation in ARPE-19 cells. In contrast, glutamate, an NMDA receptor agonist, exhibited a contrasting effect, suggesting that both the activation of autophagy and the degradation of A2E by Ro 25-6981 in ARPE-19 cells occur through inhibition of the NMDA receptor pathway. Conclusions: This study demonstrates that NMDA receptor antagonists degrade lipofuscin via autophagy in human RPE cells and suggests that NMDA receptor antagonists could be promising new therapeutics for retinal degenerative diseases.
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Tebbe L, Sakthivel H, Makia MS, Kakakhel M, Conley SM, Al-Ubaidi MR, Naash MI. Prph2 disease mutations lead to structural and functional defects in the RPE. FASEB J 2022; 36:e22284. [PMID: 35344225 PMCID: PMC10599796 DOI: 10.1096/fj.202101562rr] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Revised: 02/28/2022] [Accepted: 03/17/2022] [Indexed: 11/11/2022]
Abstract
Prph2 is a photoreceptor-specific tetraspanin with an essential role in the structure and function of photoreceptor outer segments. PRPH2 mutations cause a multitude of retinal diseases characterized by the degeneration of photoreceptors as well as defects in neighboring tissues such as the RPE. While extensive research has analyzed photoreceptors, less attention has been paid to these secondary defects. Here, we use different Prph2 disease models to evaluate the damage of the RPE arising from photoreceptor defects. In Prph2 disease models, the RPE exhibits structural abnormalities and cell loss. Furthermore, RPE functional defects are observed, including impaired clearance of phagocytosed outer segment material and increased microglia activation. The severity of RPE damage is different between models, suggesting that the different abnormal outer segment structures caused by Prph2 disease mutations lead to varying degrees of RPE stress and thus influence the clinical phenotype observed in patients.
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Affiliation(s)
- Lars Tebbe
- Department of Biomedical Engineering, University of Houston, Houston, Texas, USA
| | - Haarthi Sakthivel
- Department of Biomedical Engineering, University of Houston, Houston, Texas, USA
| | - Mustafa S. Makia
- Department of Biomedical Engineering, University of Houston, Houston, Texas, USA
| | - Mashal Kakakhel
- Department of Biomedical Engineering, University of Houston, Houston, Texas, USA
| | - Shannon M. Conley
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | - Muayyad R. Al-Ubaidi
- Department of Biomedical Engineering, University of Houston, Houston, Texas, USA
| | - Muna I. Naash
- Department of Biomedical Engineering, University of Houston, Houston, Texas, USA
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Kim MJ, Kim DH, Kwak HS, Yu IS, Um MY. Protective Effect of Chrysanthemum boreale Flower Extracts against A2E-Induced Retinal Damage in ARPE-19 Cell. Antioxidants (Basel) 2022; 11:antiox11040669. [PMID: 35453354 PMCID: PMC9024556 DOI: 10.3390/antiox11040669] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2022] [Revised: 03/23/2022] [Accepted: 03/28/2022] [Indexed: 02/04/2023] Open
Abstract
In age-related macular degeneration, N-retinylidene-N-retinylethanolamine (A2E) accumulates in retinal pigment epithelium (RPE) cells and generates oxidative stress, which further induces cell death. Polyphenols are well known for their antioxidant and beneficial effects on vision. Chrysanthemum boreale Makino (CB) flowers, which contain flavonoids, have antioxidant activity. We hypothesized that polyphenols in ethanolic extracts of CB (CBE) and its fractions suppressed A2E-mediated ARPE-19 cell damage, a human RPE cell line. CBE is rich in polyphenols, shows antioxidant activity, and suppresses intracellular accumulation of A2E and cell death induced by A2E. Among the five fractions, the polyphenol content and antioxidant effect were in the order of the ethyl acetate fraction (EtOAc) > butanol fraction (BuOH) > hexane fraction (Hex) > dichloromethane fraction (CH2Cl2) > water fraction (H2O). In contrast, the inhibitory ability of A2E accumulation and A2E-induced cell death was highest in H2O, followed by BuOH. In the correlation analysis, polyphenols in the H2O and BuOH fractions had a significant positive correlation with antioxidant effects, but no significant correlation with cell damage caused by A2E. Our findings suggest that substances other than polyphenols present in CBE can suppress the effects of A2E, and further research is needed.
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Affiliation(s)
- Min Jung Kim
- Research Division of Food Functionality, Korea Food Research Institute, Wanju 55365, Korea; (D.H.K.); (I.-S.Y.); (M.Y.U.)
- Correspondence: ; Tel.: +82-63-219-9380
| | - Dong Hee Kim
- Research Division of Food Functionality, Korea Food Research Institute, Wanju 55365, Korea; (D.H.K.); (I.-S.Y.); (M.Y.U.)
| | - Han Sub Kwak
- Research Division of Food Convergence, Korea Food Research Institute, Wanju 55365, Korea;
| | - In-Sun Yu
- Research Division of Food Functionality, Korea Food Research Institute, Wanju 55365, Korea; (D.H.K.); (I.-S.Y.); (M.Y.U.)
| | - Min Young Um
- Research Division of Food Functionality, Korea Food Research Institute, Wanju 55365, Korea; (D.H.K.); (I.-S.Y.); (M.Y.U.)
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11
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Ren J, Ren A, Deng X, Huang Z, Jiang Z, Li Z, Gong Y. Long-Chain Polyunsaturated Fatty Acids and Their Metabolites Regulate Inflammation in Age-Related Macular Degeneration. J Inflamm Res 2022; 15:865-880. [PMID: 35173457 PMCID: PMC8842733 DOI: 10.2147/jir.s347231] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Accepted: 01/20/2022] [Indexed: 12/24/2022] Open
Abstract
Age-related macular degeneration (AMD) is a blinding eye disease, whose incidence strongly increases with ages. The etiology of AMD is complex, including aging, abnormal lipid metabolism, chronic inflammation and oxidative stress. Long-chain polyunsaturated fatty acids (LCPUFA) are essential for ocular structures and functions. This review summarizes the regulatory effects of LCPUFA on inflammation in AMD. LCPUFA are related to aging, autophagy and chronic inflammation. They are metabolized to pro- and anti-inflammatory metabolites by various enzymes. These metabolites stimulate inflammation in response to oxidative stress, causing innate and acquired immune responses. This review also discusses the possible clinical applications, which provided novel targets for the prevention and treatment of AMD and other age-related diseases.
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Affiliation(s)
- Jiangbo Ren
- Department of Biological Repositories, Zhongnan Hospital of Wuhan University, Wuhan, Hubei, People’s Republic of China
- Department of Ophthalmology, Zhongnan Hospital of Wuhan University, Wuhan, Hubei, People’s Republic of China
| | - Anli Ren
- Department of Biological Repositories, Zhongnan Hospital of Wuhan University, Wuhan, Hubei, People’s Republic of China
- Department of Ophthalmology, Zhongnan Hospital of Wuhan University, Wuhan, Hubei, People’s Republic of China
| | - Xizhi Deng
- Department of Ophthalmology, Zhongnan Hospital of Wuhan University, Wuhan, Hubei, People’s Republic of China
| | - Zhengrong Huang
- Department of Biological Repositories, Zhongnan Hospital of Wuhan University, Wuhan, Hubei, People’s Republic of China
| | - Ziyu Jiang
- Department of Biological Repositories, Zhongnan Hospital of Wuhan University, Wuhan, Hubei, People’s Republic of China
| | - Zhi Li
- Department of Ophthalmology, Zhongnan Hospital of Wuhan University, Wuhan, Hubei, People’s Republic of China
| | - Yan Gong
- Department of Biological Repositories, Zhongnan Hospital of Wuhan University, Wuhan, Hubei, People’s Republic of China
- Human Genetics Resource Preservation Center of Wuhan University, Wuhan University, Wuhan, Hubei, People’s Republic of China
- Correspondence: Yan Gong; Zhi Li, Tel +86 27 6781 1461; +86 27 6781 2622, Fax +86 27 6781 1471; +86 27 6781 3133, Email ;
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12
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Mugisho OO, Green CR. The NLRP3 inflammasome in age-related eye disease: Evidence-based connexin hemichannel therapeutics. Exp Eye Res 2021; 215:108911. [PMID: 34958779 DOI: 10.1016/j.exer.2021.108911] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 11/25/2021] [Accepted: 12/21/2021] [Indexed: 12/21/2022]
Abstract
The inflammasome pathway is a fundamental component of the innate immune system, playing a key role especially in chronic age-related eye diseases (AREDs). The inflammasome is of particular interest because it is a common disease pathway that once instigated, can amplify and perpetuate itself leading to chronic inflammation. With aging, it becomes more difficult to shut down inflammation after an insult but the common pathway means that a shared solution may be feasible that could be effective across multiple disease indications. This review focusses on the NLRP3 inflammasome, the most studied and characterized inflammasome in the eye. It describes the two-step signalling required for NLRP3 inflammasome complex activation, and provides evidence for its role in AREDs. In the final section, the article gives an overview of potential NLRP3 inflammasome targeting therapies, before presenting evidence for connexin hemichannel regulators as upstream blockers of inflammasome activation. These have shown therapeutic efficacy in multiple ocular disease models.
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Affiliation(s)
- Odunayo O Mugisho
- Buchanan Ocular Therapeutics Unit, Department of Ophthalmology, New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand.
| | - Colin R Green
- Department of Ophthalmology, New Zealand National Eye Centre, University of Auckland, New Zealand
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Epithelial phenotype restoring drugs suppress macular degeneration phenotypes in an iPSC model. Nat Commun 2021; 12:7293. [PMID: 34911940 PMCID: PMC8674335 DOI: 10.1038/s41467-021-27488-x] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Accepted: 11/16/2021] [Indexed: 01/14/2023] Open
Abstract
Age-related Macular Degeneration (AMD), a blinding eye disease, is characterized by pathological protein- and lipid-rich drusen deposits underneath the retinal pigment epithelium (RPE) and atrophy of the RPE monolayer in advanced disease stages - leading to photoreceptor cell death and vision loss. Currently, there are no drugs that stop drusen formation or RPE atrophy in AMD. Here we provide an iPSC-RPE AMD model that recapitulates drusen and RPE atrophy. Drusen deposition is dependent on AMD-risk-allele CFH(H/H) and anaphylatoxin triggered alternate complement signaling via the activation of NF-κB and downregulation of autophagy pathways. Through high-throughput screening we identify two drugs, L-745,870, a dopamine receptor antagonist, and aminocaproic acid, a protease inhibitor that reduce drusen deposits and restore RPE epithelial phenotype in anaphylatoxin challenged iPSC-RPE with or without the CFH(H/H) genotype. This comprehensive iPSC-RPE model replicates key AMD phenotypes, provides molecular insight into the role of CFH(H/H) risk-allele in AMD, and discovers two candidate drugs to treat AMD.
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Isla-Magrané H, Veiga A, García-Arumí J, Duarri A. Multiocular organoids from human induced pluripotent stem cells displayed retinal, corneal, and retinal pigment epithelium lineages. Stem Cell Res Ther 2021; 12:581. [PMID: 34809716 PMCID: PMC8607587 DOI: 10.1186/s13287-021-02651-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Accepted: 11/05/2021] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Recently, great efforts have been made to design protocols for obtaining ocular cells from human stem cells to model diseases or for regenerative purposes. Current protocols generally focus on isolating retinal cells, retinal pigment epithelium (RPE), or corneal cells and fail to recapitulate the complexity of the tissue during eye development. Here, the generation of more advanced in vitro multiocular organoids from human induced pluripotent stem cells (hiPSCs) is demonstrated. METHODS A 2-step method was established to first obtain self-organized multizone ocular progenitor cells (mzOPCs) from 2D hiPSC cultures within three weeks. Then, after the cells were manually isolated and grown in suspension, 3D multiocular organoids were generated to model important cellular features of developing eyes. RESULTS In the 2D culture, self-formed mzOPCs spanned the neuroectoderm, surface ectoderm, neural crest, and RPE, mimicking early stages of eye development. After lifting, mzOPCs developed into different 3D multiocular organoids composed of multiple cell lineages including RPE, retina, and cornea, and interactions between the different cell types and regions of the eye system were observed. Within these organoids, the retinal regions exhibited correct layering and contained all major retinal cell subtypes as well as retinal morphological cues, whereas the corneal regions closely resembled the transparent ocular-surface epithelium and contained of corneal, limbal, and conjunctival epithelial cells. The arrangement of RPE cells also formed organoids composed of polarized pigmented epithelial cells at the surface that were completely filled with collagen matrix. CONCLUSIONS This approach clearly demonstrated the advantages of the combined 2D-3D construction tissue model as it provided a more ocular native-like cellular environment than that of previous models. In this complex preparations, multiocular organoids may be used to model the crosstalk between different cell types in eye development and disease.
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Affiliation(s)
- Helena Isla-Magrané
- Ophthalmology Research Group, Vall d'Hebron Institut de Recerca (VHIR), Vall d'Hebron Barcelona Hospital Campus, Passeig Vall d'Hebron 119-129, 08035, Barcelona, Spain
| | - Anna Veiga
- Regenerative Medicine Program IDIBELL, L'Hospitalet de Llobregat, Barcelona, Spain
| | - José García-Arumí
- Ophthalmology Research Group, Vall d'Hebron Institut de Recerca (VHIR), Vall d'Hebron Barcelona Hospital Campus, Passeig Vall d'Hebron 119-129, 08035, Barcelona, Spain
- Department of Ophthalmology, Vall d'Hebron Hospital Universitari, Barcelona, Spain
- Department of Ophthalmology, Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - Anna Duarri
- Ophthalmology Research Group, Vall d'Hebron Institut de Recerca (VHIR), Vall d'Hebron Barcelona Hospital Campus, Passeig Vall d'Hebron 119-129, 08035, Barcelona, Spain.
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15
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Podlipec R, Mur J, Petelin J, Štrancar J, Petkovšek R. Method for controlled tissue theranostics using a single tunable laser source. BIOMEDICAL OPTICS EXPRESS 2021; 12:5881-5893. [PMID: 34692222 PMCID: PMC8515989 DOI: 10.1364/boe.428467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Revised: 08/07/2021] [Accepted: 08/13/2021] [Indexed: 06/13/2023]
Abstract
Tissue diseases and related disorders need to be first recognized using diagnostic methods and then later treated by therapeutic methods-a joint procedure called theranostics. One of the main challenges in the field of retinal therapies remains in the success of the treatment, typically improving the local metabolism, by sparing the surrounding tissue and with the immediate information of the laser effect. In our study, we present a concept for real-time controlled tissue theranostics on a proof-of-concept study capable of using a single tunable ps laser source (in terms of irradiance, fluence, and repetition rate), done on ex-vivo human retinal pigment epithelium. We have found autofluorescence intensity and lifetime imaging diagnostics very promising for the recognition and quantification of laser effects ranging from selective non-destructive molecular tissue modification to complete tissue ablation. The main novelty of our work presents the developed algorithm for optimized theranostics based on the model function used to quantify laser-induced tissue changes through the diagnostics descriptors, fluorescence lifetime and fluorescence intensity parameters. This approach, together with the operation of the single adaptable laser source, can serve as a new theranostics method in personalized medicine in the future not only limited to treat retinal diseases.
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Affiliation(s)
- Rok Podlipec
- Laboratory of Biophysics, Condensed Matter Physics Department, Jožef Stefan Institute, Jamova cesta 39, Ljubljana, Slovenia
- Helmholtz-Zentrum Dresden-Rossendorf e.V., Ion Beam Center, Bautzner Landstraße 400, Dresden 01328, Germany
| | - Jaka Mur
- Faculty of Mechanical Engineering, University of Ljubljana, Aškerčeva 6, Ljubljana, Slovenia
| | - Jaka Petelin
- Faculty of Mechanical Engineering, University of Ljubljana, Aškerčeva 6, Ljubljana, Slovenia
| | - Janez Štrancar
- Laboratory of Biophysics, Condensed Matter Physics Department, Jožef Stefan Institute, Jamova cesta 39, Ljubljana, Slovenia
| | - Rok Petkovšek
- Faculty of Mechanical Engineering, University of Ljubljana, Aškerčeva 6, Ljubljana, Slovenia
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Possible A2E Mutagenic Effects on RPE Mitochondrial DNA from Innovative RNA-Seq Bioinformatics Pipeline. Antioxidants (Basel) 2020; 9:antiox9111158. [PMID: 33233726 PMCID: PMC7699917 DOI: 10.3390/antiox9111158] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 11/12/2020] [Accepted: 11/18/2020] [Indexed: 01/10/2023] Open
Abstract
Mitochondria are subject to continuous oxidative stress stimuli that, over time, can impair their genome and lead to several pathologies, like retinal degenerations. Our main purpose was the identification of mtDNA variants that might be induced by intense oxidative stress determined by N-retinylidene-N-retinylethanolamine (A2E), together with molecular pathways involving the genes carrying them, possibly linked to retinal degeneration. We performed a variant analysis comparison between transcriptome profiles of human retinal pigment epithelial (RPE) cells exposed to A2E and untreated ones, hypothesizing that it might act as a mutagenic compound towards mtDNA. To optimize analysis, we proposed an integrated approach that foresaw the complementary use of the most recent algorithms applied to mtDNA data, characterized by a mixed output coming from several tools and databases. An increased number of variants emerged following treatment. Variants mainly occurred within mtDNA coding sequences, corresponding with either the polypeptide-encoding genes or the RNA. Time-dependent impairments foresaw the involvement of all oxidative phosphorylation complexes, suggesting a serious damage to adenosine triphosphate (ATP) biosynthesis, that can result in cell death. The obtained results could be incorporated into clinical diagnostic settings, as they are hypothesized to modulate the phenotypic expression of mtDNA pathogenic variants, drastically improving the field of precision molecular medicine.
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Kim DH, Choi YR, Shim J, Choi YS, Kim YT, Kim MK, Kim MJ. Suppressive Effect of Arctium Lappa L. Leaves on Retinal Damage Against A2E-Induced ARPE-19 Cells and Mice. Molecules 2020; 25:molecules25071737. [PMID: 32283798 PMCID: PMC7180975 DOI: 10.3390/molecules25071737] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 04/04/2020] [Accepted: 04/08/2020] [Indexed: 01/09/2023] Open
Abstract
Age-related macular degeneration (AMD) is a major cause of irreversible loss of vision with 80–90% of patients demonstrating dry type AMD. Dry AMD could possibly be prevented by polyphenol-rich medicinal foods by the inhibition of N-retinylidene-N-retinylethanolamine (A2E)-induced oxidative stress and cell damage. Arctium lappa L. (AL) leaves are medicinal and have antioxidant activity. The purpose of this study was to elucidate the protective effects of the extract of AL leaves (ALE) on dry AMD models, including in vitro A2E-induced damage in ARPE-19 cells, a human retinal pigment epithelial cell line, and in vivo light-induced retinal damage in BALB/c mice. According to the total phenolic contents (TPCs), total flavonoid contents (TFCs) and antioxidant activities, ALE was rich in polyphenols and had antioxidant efficacies on 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), ferric reducing antioxidant power (FRAP), and 2′,7′-dichlorofluorescin diacetate (DCFDA) assays. The effects of ALE on A2E accumulation and A2E-induced cell death were also monitored. Despite continued exposure to A2E (10 μM), ALE attenuated A2E accumulation in APRE-19 cells with levels similar to lutein. A2E-induced cell death at high concentration (25 μM) was also suppressed by ALE by inhibiting the apoptotic signaling pathway. Furthermore, ALE could protect the outer nuclear layer (ONL) in the retina from light-induced AMD in BALB/c mice. In conclusion, ALE could be considered a potentially valuable medicinal food for dry AMD.
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Affiliation(s)
- Dong Hee Kim
- Research Division of Food Functionality, Korea Food Research Institute, Wanju 55365, Korea; (D.H.K.); (Y.R.C.); (J.S.); (Y.T.K.)
- Department of Food Science and Human Nutrition, Jeonbuk National University, Jeonju-si 54896, Korea;
| | - Yae Rim Choi
- Research Division of Food Functionality, Korea Food Research Institute, Wanju 55365, Korea; (D.H.K.); (Y.R.C.); (J.S.); (Y.T.K.)
- Department of Food Science and Engineering, Ewha Womans University, Seoul 03760, Korea
| | - Jaewon Shim
- Research Division of Food Functionality, Korea Food Research Institute, Wanju 55365, Korea; (D.H.K.); (Y.R.C.); (J.S.); (Y.T.K.)
| | - Yun-Sang Choi
- Research Division of Strategic Food Technology, Korea Food Research Institute, Wanju 55365, Korea;
| | - Yun Tai Kim
- Research Division of Food Functionality, Korea Food Research Institute, Wanju 55365, Korea; (D.H.K.); (Y.R.C.); (J.S.); (Y.T.K.)
- Department of Food Biotechnology, Korea University of Science & Technology, Daejeon 34113, Korea
| | - Mina Kyungmin Kim
- Department of Food Science and Human Nutrition, Jeonbuk National University, Jeonju-si 54896, Korea;
| | - Min Jung Kim
- Research Division of Food Functionality, Korea Food Research Institute, Wanju 55365, Korea; (D.H.K.); (Y.R.C.); (J.S.); (Y.T.K.)
- Correspondence: ; Tel.: +82-63-219-9380
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18
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Autophagy and Age-Related Eye Diseases. BIOMED RESEARCH INTERNATIONAL 2019; 2019:5763658. [PMID: 31950044 PMCID: PMC6948295 DOI: 10.1155/2019/5763658] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/26/2019] [Revised: 08/08/2019] [Accepted: 08/26/2019] [Indexed: 12/12/2022]
Abstract
Background Autophagy is a catabolic process that depends on the lysosome. It is usually used to maintain cellular homeostasis, survival and development by degrading abnormal substances and dysfunctional organelles, especially when the cell is exposed to starvation or other stresses. Increasing studies have reported that autophagy is associated with various eye diseases, of which aging is one of the important factors. Objective To summarize the functional and regulatory role of autophagy in ocular diseases with aging, and discuss the possibility of autophagy-targeted therapy in age-related diseases. Methods PubMed searches were performed to identify relevant articles published mostly in the last 5 years. The key words were used to retrieve including “autophagy”, “aging”, “oxidative stress AND autophagy”, “dry eye AND autophagy”, “corneal disease AND autophagy”, “glaucoma AND autophagy”, “cataract AND autophagy”, “AMD AND autophagy”, “cardiovascular diseases AND autophagy”, “diabetes AND autophagy”. After being classified and assessed, the most relevant full texts in English were chosen. Results Apart from review articles, more than two research articles for each age-related eye diseases related to autophagy were retrieved. We only included the most relevant and recent studies for summary and discussion. Conclusion Autophagy has both protective and detrimental effects on the progress of age-related eye diseases. Different types of studies based on certain situations in vitro showed distinct results, which do not necessarily coincide with the actual situation in human bodies completely. It means the exact role and regulatory function of autophagy in ocular diseases remains largely unknown. Although autophagy as a potential therapeutic target has been proposed, many problems still need to be solved before it applies to clinical practice.
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19
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Jeong SY, Gu X, Jeong KW. Photoactivation of N-retinylidene-N-retinylethanolamine compromises autophagy in retinal pigmented epithelial cells. Food Chem Toxicol 2019; 131:110555. [PMID: 31173818 DOI: 10.1016/j.fct.2019.06.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Revised: 05/30/2019] [Accepted: 06/01/2019] [Indexed: 01/05/2023]
Abstract
As a part of the aging process, N-retinylidene-N-retinylethanolamine (A2E) accumulates in the retina to activate autophagy in retinal pigmented epithelial cells. However, the effect of A2E photoactivation on autophagy, which is more clinically relevant, still remains unclear. Here, we investigated the effect of blue light (BL)-activated A2E on autophagy in human retinal pigmented epithelial cells, ARPE-19. A significant increase in LC3-II protein was observed when BL was irradiated on ARPE-19 cells containing A2E. The mammalian target of rapamycin (mTOR) pathway was examined to verify whether autophagy was activated, but no change in AKT, mTOR, and 4EBP phosphorylation was observed. Transcription factor EB (TFEB) target gene expression, which is another pathway involved in autophagy, was also not altered by A2E and BL. However, intracellular p62 protein levels were significantly increased, which represented the inhibition of autophagic flux. To investigate the mechanism of the suppressed autophagic flux, the lysosomal state was observed. After BL irradiation, lysosomal damage was induced in A2E-treated ARPE-19 cells, and this phenomenon was prevented by treatment with the antioxidant, N-acetylcysteine. Our results suggest that A2E photoactivation compromises autophagy in ARPE-19 cells and that reactive oxygen species (ROS) play an important role in this process.
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Affiliation(s)
- Seo Yeon Jeong
- Gachon Institute of Pharmaceutical Sciences, College of Pharmacy, Gachon University, 191 Hambakmoero, Yeonsu-gu, Incheon, 21936, Republic of Korea
| | - XiuHui Gu
- Gachon Institute of Pharmaceutical Sciences, College of Pharmacy, Gachon University, 191 Hambakmoero, Yeonsu-gu, Incheon, 21936, Republic of Korea
| | - Kwang Won Jeong
- Gachon Institute of Pharmaceutical Sciences, College of Pharmacy, Gachon University, 191 Hambakmoero, Yeonsu-gu, Incheon, 21936, Republic of Korea.
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20
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Wang S, Wang X, Cheng Y, Ouyang W, Sang X, Liu J, Su Y, Liu Y, Li C, Yang L, Jin L, Wang Z. Autophagy Dysfunction, Cellular Senescence, and Abnormal Immune-Inflammatory Responses in AMD: From Mechanisms to Therapeutic Potential. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2019; 2019:3632169. [PMID: 31249643 PMCID: PMC6556250 DOI: 10.1155/2019/3632169] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Accepted: 04/17/2019] [Indexed: 12/22/2022]
Abstract
Age-related macular degeneration (AMD) is a blinding disease caused by multiple factors and is the primary cause of vision loss in the elderly. The morbidity of AMD increases every year. Currently, there is no effective treatment option for AMD. Intravitreal injection of antivascular endothelial growth factor (anti-VEGF) is currently the most widely used therapy, but it only aims at neovascularization, which is an intermediate pathological phenomenon of wet AMD, not at the etiological treatment. Anti-VEGF therapy can only temporarily delay the degeneration process of wet AMD, and AMD is easy to relapse after drug withdrawal. Therefore, it is urgent to deepen our understanding of the pathophysiological processes underlying AMD and to identify integrated or new strategies for AMD prevention and treatment. Recent studies have found that autophagy dysfunction in retinal pigment epithelial (RPE) cells, cellular senescence, and abnormal immune-inflammatory responses play key roles in the pathogenesis of AMD. For many age-related diseases, the main focus is currently the clearing of senescent cells (SNCs) as an antiaging treatment, thereby delaying diseases. However, in AMD, there is no relevant antiaging application. This review will discuss the pathogenesis of AMD and how interactions among RPE autophagy dysfunction, cellular senescence, and abnormal immune-inflammatory responses are involved in AMD, and it will summarize the three antiaging strategies that have been developed, with the aim of providing important information for the integrated prevention and treatment of AMD and laying the ground work for the application of antiaging strategies in AMD treatment.
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Affiliation(s)
- Shoubi Wang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510060, China
| | - Xiaoran Wang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510060, China
| | - Yaqi Cheng
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510060, China
| | - Weijie Ouyang
- Eye Institute of Xiamen University, Fujian Provincial Key Laboratory of Ophthalmology and Visual Science, School of Medicine, Xiamen University, Xiamen 361102, China
| | - Xuan Sang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510060, China
| | - Jiahui Liu
- Department of Ophthalmology, Dongguan People's Hospital, Dongguan 523059, China
| | - Yaru Su
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510060, China
| | - Ying Liu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510060, China
| | - Chaoyang Li
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510060, China
| | - Liu Yang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510060, China
| | - Lin Jin
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510060, China
| | - Zhichong Wang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510060, China
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21
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Rosales MAB, Shu DY, Iacovelli J, Saint-Geniez M. Loss of PGC-1α in RPE induces mesenchymal transition and promotes retinal degeneration. Life Sci Alliance 2019; 2:2/3/e201800212. [PMID: 31101737 PMCID: PMC6526284 DOI: 10.26508/lsa.201800212] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Revised: 05/07/2019] [Accepted: 05/09/2019] [Indexed: 01/07/2023] Open
Abstract
Sustained loss of PGC-1α in RPE cells triggers mitochondrial/autophagic dysfunction and oxidative damage resulting in epithelial dedifferentiation and mesenchymal transition. RPE dysfunction caused by deletion of the PGC-1 coactivators in vivo causes retinal degeneration. The retinal pigment epithelium (RPE) supports visual processing and photoreceptor homeostasis via energetically demanding cellular functions. Here, we describe the consequences of repressing peroxisome proliferator-activated receptor γ coactivator-1 α (PGC-1α), a master regulator of mitochondrial function and biogenesis, on RPE epithelial integrity. The sustained silencing of PGC-1α in differentiating human RPE cells affected mitochondria/autophagy function, redox state, and impaired energy sensor activity ultimately inducing epithelial to mesenchymal transition (EMT). Adult conditional knockout of PGC-1 coactivators in mice resulted in rapid RPE dysfunction and transdifferentiation associated with severe photoreceptor degeneration. RPE anomalies were characteristic of autophagic defect and mesenchymal transition comparable with the ones observed in age-related macular degeneration. These findings demonstrate that PGC-1α is required to maintain the functional and phenotypic status of RPE by supporting the cells’ oxidative metabolism and autophagy-mediated repression of EMT.
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Affiliation(s)
- Mariana Aparecida Brunini Rosales
- Schepens Eye Research Institute of Massachusetts Eye and Ear, Boston, MA.,Department of Ophthalmology, Harvard Medical School, Boston, MA
| | - Daisy Y Shu
- Schepens Eye Research Institute of Massachusetts Eye and Ear, Boston, MA.,Department of Ophthalmology, Harvard Medical School, Boston, MA
| | - Jared Iacovelli
- Schepens Eye Research Institute of Massachusetts Eye and Ear, Boston, MA.,Department of Ophthalmology, Harvard Medical School, Boston, MA
| | - Magali Saint-Geniez
- Schepens Eye Research Institute of Massachusetts Eye and Ear, Boston, MA .,Department of Ophthalmology, Harvard Medical School, Boston, MA
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Dalvi S, Galloway CA, Winschel L, Hashim A, Soto C, Tang C, MacDonald LA, Singh R. Environmental stress impairs photoreceptor outer segment (POS) phagocytosis and degradation and induces autofluorescent material accumulation in hiPSC-RPE cells. Cell Death Discov 2019; 5:96. [PMID: 31123602 PMCID: PMC6522536 DOI: 10.1038/s41420-019-0171-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Revised: 03/19/2019] [Accepted: 03/21/2019] [Indexed: 11/09/2022] Open
Abstract
Retinal pigment epithelium (RPE) cell dysfunction is central to the pathogenesis of age-related macular degeneration (AMD), a leading cause of adult blindness. Aging, the single biggest risk factor for AMD development, favors increase in RPE autofluorescent material due to accumulation of POS-digestion by-products through lysosomal dysfunction and impaired POS degradation. Apart from aging, environmental agents affect lysosomal function in multiple model systems and are implicated in AMD. Iron (Fe) overload and cigarette smoke exposure are the two environmental factors that are known to affect the lysosomal pathway and impact RPE cell health. However, the impact of Fe and cigarette smoke, on POS processing and its consequence for autofluorescent material accumulation in human RPE cells are yet to be established. Human induced pluripotent stem cell (hiPSC)-derived RPE, which phagocytoses and degrades POS in culture and can be derived from control individuals (no history/susceptibility for retinal disease), provides a model system to investigate the singular effect of excess Fe and/or cigarette smoke on POS processing by RPE cells. Using at least three distinct control hiPSC lines, we show that, compared to untreated hiPSC-RPE cells, POS uptake is reduced in both Fe (ferric ammonium citrate or FAC) and FAC + CSE (cigarette smoke extract)-treated hiPSC-RPE cells. Furthermore, exposure of hiPSC-RPE cultures to FAC + CSE leads to reduced levels of active cathepsin-D (CTSD), a lysosomal enzyme involved in POS processing, and causes delayed degradation of POS. Notably, delayed degradation of POS over time (2 weeks) in hiPSC-RPE cells exposed to Fe and CSE was sufficient to increase autofluorescent material build-up in these cells. Given that inefficient POS processing-mediated autofluorescent material accumulation in RPE cells has already been linked to AMD development, our results implicate a causative role of environmental agents, like Fe and cigarette smoke, in AMD.
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Affiliation(s)
- Sonal Dalvi
- 1Department of Ophthalmology (Flaum Eye Institute), University of Rochester, Rochester, NY USA.,2Department of Biomedical Genetics, University of Rochester, Rochester, NY USA
| | - Chad A Galloway
- 1Department of Ophthalmology (Flaum Eye Institute), University of Rochester, Rochester, NY USA.,2Department of Biomedical Genetics, University of Rochester, Rochester, NY USA.,5Present Address: Department of Pathology and Lab Medicine, University of Rochester, Rochester, NY USA
| | - Lauren Winschel
- 1Department of Ophthalmology (Flaum Eye Institute), University of Rochester, Rochester, NY USA.,2Department of Biomedical Genetics, University of Rochester, Rochester, NY USA
| | - Ali Hashim
- 1Department of Ophthalmology (Flaum Eye Institute), University of Rochester, Rochester, NY USA.,2Department of Biomedical Genetics, University of Rochester, Rochester, NY USA
| | - Celia Soto
- 1Department of Ophthalmology (Flaum Eye Institute), University of Rochester, Rochester, NY USA.,2Department of Biomedical Genetics, University of Rochester, Rochester, NY USA
| | - Cynthia Tang
- 1Department of Ophthalmology (Flaum Eye Institute), University of Rochester, Rochester, NY USA.,2Department of Biomedical Genetics, University of Rochester, Rochester, NY USA
| | - Leslie A MacDonald
- 1Department of Ophthalmology (Flaum Eye Institute), University of Rochester, Rochester, NY USA.,2Department of Biomedical Genetics, University of Rochester, Rochester, NY USA
| | - Ruchira Singh
- 1Department of Ophthalmology (Flaum Eye Institute), University of Rochester, Rochester, NY USA.,2Department of Biomedical Genetics, University of Rochester, Rochester, NY USA.,3UR Stem Cell and Regenerative Medicine Institute, Rochester, NY USA.,4Center for Visual Science, University of Rochester, Rochester, NY USA
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Fatty acids and oxidized lipoproteins contribute to autophagy and innate immunity responses upon the degeneration of retinal pigment epithelium and development of age-related macular degeneration. Biochimie 2019; 159:49-54. [DOI: 10.1016/j.biochi.2018.07.010] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Accepted: 07/17/2018] [Indexed: 12/18/2022]
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Conservation of structure, function and inhibitor binding in UNC-51-like kinase 1 and 2 (ULK1/2). Biochem J 2019; 476:875-887. [PMID: 30782972 DOI: 10.1042/bcj20190038] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Revised: 02/14/2019] [Accepted: 02/19/2019] [Indexed: 12/20/2022]
Abstract
Autophagy is essential for cellular homeostasis and when deregulated this survival mechanism has been associated with disease development. Inhibition of autophagy initiation by inhibiting the kinase ULK1 (Unc-51-like autophagy activating kinase 1) has been proposed as a potential cancer therapy. While inhibitors and crystal structures of ULK1 have been reported, little is known about the other closely related kinase ULK2 (Unc-51-like autophagy activating kinase 2). Here, we present the crystal structure of ULK2 in complex with ATP competitive inhibitors. Surprisingly, the ULK2 structure revealed a dimeric assembly reminiscent of dimeric arrangements of auto-activating kinases suggesting a role for this association in ULK activation. Screening of a kinase focused library of pre-clinical and clinical compounds revealed several potent ULK1/2 inhibitors and good correlation of inhibitor-binding behavior with both ULK kinases. Aurora A was identified as a major off-target of currently used ULK1 inhibitors. Autophagic flux assays demonstrated that this off-target activity by strongly inducing autophagy in different cellular systems conferred an additional layer of complexity in the interpretation of cellular data. The data presented here provide structural models and chemical starting points for the development of ULK1/2 dual inhibitors with improved selectivity for future exploitation of autophagy inhibition.
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Interplay between Autophagy and the Ubiquitin-Proteasome System and Its Role in the Pathogenesis of Age-Related Macular Degeneration. Int J Mol Sci 2019; 20:ijms20010210. [PMID: 30626110 PMCID: PMC6337628 DOI: 10.3390/ijms20010210] [Citation(s) in RCA: 83] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Revised: 12/21/2018] [Accepted: 01/02/2019] [Indexed: 12/20/2022] Open
Abstract
Age-related macular degeneration (AMD) is a complex eye disease with many pathogenesis factors, including defective cellular waste management in retinal pigment epithelium (RPE). Main cellular waste in AMD are: all-trans retinal, drusen and lipofuscin, containing unfolded, damaged and unneeded proteins, which are degraded and recycled in RPE cells by two main machineries—the ubiquitin-proteasome system (UPS) and autophagy. Recent findings show that these systems can act together with a significant role of the EI24 (etoposide-induced protein 2.4 homolog) ubiquitin ligase in their action. On the other hand, E3 ligases are essential in both systems, but E3 is degraded by autophagy. The interplay between UPS and autophagy was targeted in several diseases, including Alzheimer disease. Therefore, cellular waste clearing in AMD should be considered in the context of such interplay rather than either of these systems singly. Aging and oxidative stress, two major AMD risk factors, reduce both UPS and autophagy. In conclusion, molecular mechanisms of UPS and autophagy can be considered as a target in AMD prevention and therapeutic perspective. Further work is needed to identify molecules and effects important for the coordination of action of these two cellular waste management systems.
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Saito Y, Kuse Y, Inoue Y, Nakamura S, Hara H, Shimazawa M. Transient acceleration of autophagic degradation by pharmacological Nrf2 activation is important for retinal pigment epithelium cell survival. Redox Biol 2018; 19:354-363. [PMID: 30216854 PMCID: PMC6138993 DOI: 10.1016/j.redox.2018.09.004] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Revised: 08/28/2018] [Accepted: 09/03/2018] [Indexed: 12/24/2022] Open
Abstract
Non-exudative age-related macular degeneration (AMD) is mainly caused by the accumulation of lipofuscin and drusen on the retinal pigment epithelium (RPE). Both oxidative stress and autophagic dysfunction accelerate the deposition of lipofuscin at the RPE. One of the key regulators in the response against oxidative stress is the NF-E2-Related Factor 2 (Nrf2)-kelch like ECH associated protein 1 (Keap1) axis, which is also closely associated with the autophagy pathway. Nrf2 activation upregulates the expression levels of certain anti-oxidative enzymes [e.g. Heme oxygenase-1 (HO-1)], which attenuates oxidative damage. However, until now, the relationship between cytoprotective effects of Nrf2 activation and autophagic degradation remain unclear. To address these questions, we investigated the effects of a novel Nrf2 activator, RS9, on RPE damage. We found that RS9 protected ARPE-19 cells against NaIO3-induced oxidative damage, and that the protective effects of RS9 were inhibited by co-treatment with zinc protoporphyrin, an HO-1 inhibitor. Next, we examined the involvement of autophagic degradation in the protective effects of RS9. Co-treatment with RS9 and chloroquine, a lysosomal acidification inhibitor, inhibited the protective effect. Furthermore, western blotting and immunostaining showed that RS9 accelerated autophagy flux and induced transient upregulation of p62 [also known as sequestosome 1 (SQSTM1)]. Co-treatment with chloroquine and RS9 also inhibited the degradation of autophagosomes. Transient upregulation of SQSTM1 by RS9 was unaltered by HO-1 knockdown using siRNA. RS9 and chloroquine had the same actions in light damaged adult zebrafish retina as those in vitro. In conclusion, we clarified the relationship between acceleration of the autophagy pathway and the cytoprotective effects of Nrf2 activation in RPE cells and zebrafish retina. These findings indicated that Nrf2 activation could be a promising therapeutic approach for non-exudative AMD by supporting RPE maintenance.
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Affiliation(s)
- Yuichi Saito
- Molecular Pharmacology, Department of Biofunctional Evaluation, Gifu Pharmaceutical University, 1-25-4 Daigakunishi, Gifu 501-1196, Japan
| | - Yoshiki Kuse
- Molecular Pharmacology, Department of Biofunctional Evaluation, Gifu Pharmaceutical University, 1-25-4 Daigakunishi, Gifu 501-1196, Japan
| | - Yuki Inoue
- Molecular Pharmacology, Department of Biofunctional Evaluation, Gifu Pharmaceutical University, 1-25-4 Daigakunishi, Gifu 501-1196, Japan
| | - Shinsuke Nakamura
- Molecular Pharmacology, Department of Biofunctional Evaluation, Gifu Pharmaceutical University, 1-25-4 Daigakunishi, Gifu 501-1196, Japan.
| | - Hideaki Hara
- Molecular Pharmacology, Department of Biofunctional Evaluation, Gifu Pharmaceutical University, 1-25-4 Daigakunishi, Gifu 501-1196, Japan.
| | - Masamitsu Shimazawa
- Molecular Pharmacology, Department of Biofunctional Evaluation, Gifu Pharmaceutical University, 1-25-4 Daigakunishi, Gifu 501-1196, Japan.
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Ramachandra Rao S, Pfeffer BA, Más Gómez N, Skelton LA, Keiko U, Sparrow JR, Rowsam AM, Mitchell CH, Fliesler SJ. Compromised phagosome maturation underlies RPE pathology in cell culture and whole animal models of Smith-Lemli-Opitz Syndrome. Autophagy 2018; 14:1796-1817. [PMID: 29979914 PMCID: PMC6135634 DOI: 10.1080/15548627.2018.1490851] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Revised: 05/25/2018] [Accepted: 06/11/2018] [Indexed: 12/27/2022] Open
Abstract
Treatment of rats with the cholesterol pathway inhibitor AY9944 produces an animal model of Smith-Lemli-Opitz syndrome (SLOS), an autosomal recessive disease caused by defective cholesterol synthesis. This SLOS rat model undergoes progressive and irreversible degeneration of the neural retina, with associated pathological features of the retinal pigmented epithelium (RPE). Here, we provide further insights into the mechanism involved in the RPE pathology. In the SLOS rat model, markedly increased RPE apical autofluorescence is observed, compared to untreated animals, which correlates with increased levels of A2E and other bisretinoids. Utilizing cultured human induced pluripotent stem cell (iPSC)- derived SLOS RPE cells, we found significantly elevated steady-state levels of 7-dehydrocholesterol (7DHC) and decreased cholesterol levels (key biochemical hallmarks of SLOS). Western blot analysis revealed altered levels of the macroautophagy/autophagy markers MAP1LC3B-II and SQSTM1/p62, and build-up of ubiquitinated proteins. Accumulation of immature autophagosomes was accompanied by inefficient degradation of phagocytized, exogenously supplied retinal rod outer segments (as evidenced by persistence of the C-terminal 1D4 epitope of RHO [rhodopsin]) in SLOS RPE compared to iPSC-derived normal human control. SLOS RPE cells exhibited lysosomal pH levels and CTSD activity within normal physiological limits, thus discounting the involvement of perturbed lysosomal function. Furthermore, 1D4-positive phagosomes that accumulated in the RPE in both pharmacological and genetic rodent models of SLOS failed to fuse with lysosomes. Taken together, these observations suggest that defective phagosome maturation underlies the observed RPE pathology. The potential relevance of these findings to SLOS and the requirement of cholesterol for phagosome maturation are discussed.
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Affiliation(s)
- Sriganesh Ramachandra Rao
- Departments of Ophthalmology (Ross Eye Institute) and Biochemistry, Jacobs School of Medicine and Biomedical Sciences, SUNY-University at Buffalo, Buffalo, NY, USA
- SUNY Eye Institute, Buffalo, NY, USA
- Research Service, VA Western NY Healthcare System, Buffalo, NY, USA
| | - Bruce A. Pfeffer
- Departments of Ophthalmology (Ross Eye Institute) and Biochemistry, Jacobs School of Medicine and Biomedical Sciences, SUNY-University at Buffalo, Buffalo, NY, USA
- SUNY Eye Institute, Buffalo, NY, USA
- Research Service, VA Western NY Healthcare System, Buffalo, NY, USA
| | - Néstor Más Gómez
- Department of Anatomy & Cell Biology, University of Pennsylvania, School of Dental Medicine, Philadelphia, PA, USA
| | - Lara A. Skelton
- Departments of Ophthalmology (Ross Eye Institute) and Biochemistry, Jacobs School of Medicine and Biomedical Sciences, SUNY-University at Buffalo, Buffalo, NY, USA
- SUNY Eye Institute, Buffalo, NY, USA
- Research Service, VA Western NY Healthcare System, Buffalo, NY, USA
| | - Ueda Keiko
- Departments of Ophthalmology (Harkness Eye Institute) and Pathology & Cell Biology, Columbia University, College of Physicians & Surgeons, NY, NY, USA
| | - Janet R. Sparrow
- Departments of Ophthalmology (Harkness Eye Institute) and Pathology & Cell Biology, Columbia University, College of Physicians & Surgeons, NY, NY, USA
| | - Aryn M. Rowsam
- Departments of Ophthalmology (Ross Eye Institute) and Biochemistry, Jacobs School of Medicine and Biomedical Sciences, SUNY-University at Buffalo, Buffalo, NY, USA
- SUNY Eye Institute, Buffalo, NY, USA
- Research Service, VA Western NY Healthcare System, Buffalo, NY, USA
| | - Claire H. Mitchell
- Department of Anatomy & Cell Biology, University of Pennsylvania, School of Dental Medicine, Philadelphia, PA, USA
| | - Steven J. Fliesler
- Departments of Ophthalmology (Ross Eye Institute) and Biochemistry, Jacobs School of Medicine and Biomedical Sciences, SUNY-University at Buffalo, Buffalo, NY, USA
- SUNY Eye Institute, Buffalo, NY, USA
- Research Service, VA Western NY Healthcare System, Buffalo, NY, USA
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Karthikeyan B, Harini L, Krishnakumar V, Kannan VR, Sundar K, Kathiresan T. Insights on the involvement of (-)-epigallocatechin gallate in ER stress-mediated apoptosis in age-related macular degeneration. Apoptosis 2018; 22:72-85. [PMID: 27778132 DOI: 10.1007/s10495-016-1318-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Endoplasmic reticulum (ER) stress-mediated apoptosis is a well-known factor in the pathogenesis of age-related macular degeneration (AMD). ER stress leads to accumulation of misfolded proteins, which in turn activates unfolded protein response (UPR) of the cell for its survival. The prolonged UPR of ER stress promotes cell death; however, the transition between adaptation and ER stress-induced apoptosis has not been clearly understood. Hence, the present study investigates the regulatory effect of (-)-epigallocatechin gallate (EGCG) on ER stress-induced by hydrogen peroxide (H2O2) and disturbance of calcium homeostasis by thapsigargin (TG) in mouse retinal pigment epithelial (MRPE) cells. The oxidant molecules influenced MRPE cells showed an increased level of intracellular calcium [Ca2+]i in ER and transferred to mitochondria through ER-mitochondrial tether site then increased ROS production. EGCG restores [Ca2+]i homeostasis by decreasing ROS production through inhibition of prohibitin1 which regulate ER-mitochondrial tether site and inhibit apoptosis. Effect of EGCG on ER stress-mediated apoptosis was elucidated by exploring the UPR signalling pathways. EGCG downregulated GRP78, CHOP, PERK, ERO1α, IRE1α, cleaved PARP, cleaved caspase 3, caspase 12 and upregulated expression of calnexinin MRPE cells. In addition to this, inhibition of apoptosis by EGCG was also confirmed with expression of proteins Akt, PTEN and GSK3β. MRPE cells with EGCG upregulates phosphorylation of Akt at ser473 and phospho ser380 of PTEN, but phosphorylation at ser9 of GSK3β was inhibited. Further, constitutively active (myristoylated) CA-Akt transfected in MRPE cells had an increased Akt activity in EGCG influenced cells. These findings strongly suggest that antioxidant molecules inhibit cell death through the proper balancing of [Ca2+]i and ROS production in order to maintain UPR of ER in MRPE cells. Thus, modulation of UPR signalling may provide a potential target for the therapeutic approaches of AMD.
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Affiliation(s)
- Bose Karthikeyan
- Department of Biotechnology, Kalasalingam University, Anand Nagar, Krishnankoil, Tamil Nadu, 626 126, India.,Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, OH, 44195, USA
| | - Lakshminarasimhan Harini
- Department of Biotechnology, Kalasalingam University, Anand Nagar, Krishnankoil, Tamil Nadu, 626 126, India
| | | | - Velu Rajesh Kannan
- Department of Microbiology, Bharathidasan University, Tiruchirappalli, Tamil Nadu, 620 024, India
| | - Krishnan Sundar
- Department of Biotechnology, Kalasalingam University, Anand Nagar, Krishnankoil, Tamil Nadu, 626 126, India.,International Research Centre, Kalasalingam University, Krishnankoil, Tamil Nadu, 626 126, India
| | - Thandavarayan Kathiresan
- Department of Biotechnology, Kalasalingam University, Anand Nagar, Krishnankoil, Tamil Nadu, 626 126, India. .,International Research Centre, Kalasalingam University, Krishnankoil, Tamil Nadu, 626 126, India.
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Xie J, Zhu R, Peng Y, Gao W, Du J, Zhao L, Chi Y, Yang L. Tumor necrosis factor-alpha regulates photoreceptor cell autophagy after retinal detachment. Sci Rep 2017; 7:17108. [PMID: 29215050 PMCID: PMC5719449 DOI: 10.1038/s41598-017-17400-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Accepted: 11/21/2017] [Indexed: 12/27/2022] Open
Abstract
Photoreceptor cell death is the ultimate process underlying many retinal diseases, including retinal detachment (RD). Both autophagy and inflammatory factors, such as tumor necrosis factor-alpha (TNF-α), participate in photoreceptor cell death after RD. In this study, we examined whether TNF-α inhibition would impact the autophagy of photoreceptors and reduce the death of photoreceptors after retinal detachment (RD). RD models were created in C57BL/6J mice by a subretinal injection of 1% hyaluronic acid. The TNF-α inhibitor infliximab was administered via intraperitoneal injection two hours before RD. The levels of TNF-α and the autophagy-related proteins Atg5 and LC3B were assayed by immunofluorescence at 1 day, 3 days, and 7 days following RD. Apoptosis was examined at 3 days post-detachment via TUNEL assays. Photoreceptor cell counts were assessed at 7 days after RD. After RD, the protein levels of LC3B and Atg5 increased and reached a peak at 3 days, which decreased at 7 days. The expression of LC3B and Atg5 was prolonged and increased at a slower rate with TNF-α inhibition. The moderate augmentation and extension of autophagy through TNF-α inhibition resulted in the reduction of apoptosis and the enhancement of photoreceptor cell survival.
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Affiliation(s)
- Jia Xie
- Department of Ophthalmology, Peking University First Hospital, No. 1 Xi'anmen Street, Xicheng District, Beijing, 100034, China
| | - Ruilin Zhu
- Department of Ophthalmology, Peking University First Hospital, No. 1 Xi'anmen Street, Xicheng District, Beijing, 100034, China
| | - Yuan Peng
- Department of Ophthalmology, Peking University First Hospital, No. 1 Xi'anmen Street, Xicheng District, Beijing, 100034, China
| | - Wenna Gao
- Department of Ophthalmology, Peking University First Hospital, No. 1 Xi'anmen Street, Xicheng District, Beijing, 100034, China
| | - Jiantong Du
- Department of Ophthalmology, Peking University First Hospital, No. 1 Xi'anmen Street, Xicheng District, Beijing, 100034, China
| | - Liang Zhao
- Department of Ophthalmology, Peking University First Hospital, No. 1 Xi'anmen Street, Xicheng District, Beijing, 100034, China
| | - Ying Chi
- Department of Ophthalmology, Peking University First Hospital, No. 1 Xi'anmen Street, Xicheng District, Beijing, 100034, China
| | - Liu Yang
- Department of Ophthalmology, Peking University First Hospital, No. 1 Xi'anmen Street, Xicheng District, Beijing, 100034, China.
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30
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Mitochondrial dysfunction underlying outer retinal diseases. Mitochondrion 2017; 36:66-76. [PMID: 28365408 DOI: 10.1016/j.mito.2017.03.006] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Revised: 03/06/2017] [Accepted: 03/27/2017] [Indexed: 01/21/2023]
Abstract
Dysfunction of photoreceptors, retinal pigment epithelium (RPE) or both contribute to the initiation and progression of several outer retinal disorders. Disrupted Müller glia function might additionally subsidize to these diseases. Mitochondrial malfunctioning is importantly associated with outer retina pathologies, which can be classified as primary and secondary mitochondrial disorders. This review highlights the importance of oxidative stress and mitochondrial DNA damage, underlying outer retinal disorders. Indeed, the metabolically active photoreceptors/RPE are highly prone to these hallmarks of mitochondrial dysfunction, indicating that mitochondria represent a weak link in the antioxidant defenses of outer retinal cells.
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31
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Tyrosinase-Cre-Mediated Deletion of the Autophagy Gene Atg7 Leads to Accumulation of the RPE65 Variant M450 in the Retinal Pigment Epithelium of C57BL/6 Mice. PLoS One 2016; 11:e0161640. [PMID: 27537685 PMCID: PMC4990303 DOI: 10.1371/journal.pone.0161640] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Accepted: 08/09/2016] [Indexed: 12/26/2022] Open
Abstract
Targeted gene knockout mouse models have helped to identify roles of autophagy in many tissues. Here, we investigated the retinal pigment epithelium (RPE) of Atg7f/f Tyr-Cre mice (on a C57BL/6 background), in which Cre recombinase is expressed under the control of the tyrosinase promoter to delete the autophagy gene Atg7. In line with pigment cell-directed blockade of autophagy, the RPE and the melanocytes of the choroid showed strong accumulation of the autophagy adaptor and substrate, sequestosome 1 (Sqstm1)/p62, relative to the levels in control mice. Immunofluorescence and Western blot analysis demonstrated that the RPE, but not the choroid melanocytes, of Atg7f/f Tyr-Cre mice also had strongly increased levels of retinoid isomerohydrolase RPE65, a pivotal enzyme for the maintenance of visual perception. In contrast to Sqstm1, genes involved in retinal regeneration, i.e. Lrat, Rdh5, Rgr, and Rpe65, were expressed at higher mRNA levels. Sequencing of the Rpe65 gene showed that Atg7f/f and Atg7f/f Tyr-Cre mice carry a point mutation (L450M) that is characteristic for the C57BL/6 mouse strain and reportedly causes enhanced degradation of the RPE65 protein by an as-yet unknown mechanism. These results suggest that the increased abundance of RPE65 M450 in the RPE of Atg7f/f Tyr-Cre mice is, at least partly, mediated by upregulation of Rpe65 transcription; however, our data are also compatible with the hypothesis that the RPE65 M450 protein is degraded by Atg7-dependent autophagy in Atg7f/f mice. Further studies in mice of different genetic backgrounds are necessary to determine the relative contributions of these mechanisms.
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Ye F, Kaneko H, Hayashi Y, Takayama K, Hwang SJ, Nishizawa Y, Kimoto R, Nagasaka Y, Tsunekawa T, Matsuura T, Yasukawa T, Kondo T, Terasaki H. Malondialdehyde induces autophagy dysfunction and VEGF secretion in the retinal pigment epithelium in age-related macular degeneration. Free Radic Biol Med 2016; 94:121-34. [PMID: 26923802 DOI: 10.1016/j.freeradbiomed.2016.02.027] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Revised: 02/19/2016] [Accepted: 02/22/2016] [Indexed: 11/22/2022]
Abstract
Age-related macular degeneration (AMD) is a major cause of blindness in developed countries and is closely related to oxidative stress, which leads to lipid peroxidation. Malondialdehyde (MDA) is a major byproduct of polyunsaturated fatty acid (PUFA) peroxidation. Increased levels of MDA have been reported in eyes of AMD patients. However, little is known about the direct relationship between MDA and AMD. Here we show the biological importance of MDA in AMD pathogenesis. We first confirmed that MDA levels were significantly increased in eyes of AMD patients. In ARPE-19 cells, a human retinal pigment epithelial cell line, MDA treatment induced vascular endothelial growth factor (VEGF) expression alternation, cell junction disruption, and autophagy dysfunction that was also observed in eyes of AMD patients. The MDA-induced VEGF increase was inhibited by autophagy-lysosomal inhibitors. Intravitreal MDA injection in mice increased laser-induced choroidal neovascularization (laser-CNV) volumes. In a mouse model fed a high-linoleic acid diet for 3 months, we found a significant increase in MDA levels, autophagic activity, and laser-CNV volumes. Our study revealed an important role of MDA, which acts not only as a marker but also as a causative factor of AMD pathogenesis-related autophagy dysfunction. Furthermore, higher dietary intake of linoleic acid promoted CNV progression in mice with increased MDA levels.
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Affiliation(s)
- Fuxiang Ye
- Department of Ophthalmology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
| | - Hiroki Kaneko
- Department of Ophthalmology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan.
| | - Yumi Hayashi
- Department of Radiological and Medical Laboratory Sciences, Nagoya University Graduate School of Medicine, Nagoya 461-8673, Japan; Institute for Advanced Research, Nagoya University, Nagoya 464-8601, Japan
| | - Kei Takayama
- Department of Ophthalmology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
| | - Shiang-Jyi Hwang
- Department of Ophthalmology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan; Laboratory of Bell Research Center-Department of Obstetrics and Gynecology Collaborative Research, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
| | - Yuji Nishizawa
- Department of Biomedical Sciences, Chubu University, Kasugai, Aichi 487-8501, Japan
| | - Reona Kimoto
- Department of Ophthalmology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
| | - Yosuke Nagasaka
- Department of Ophthalmology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
| | - Taichi Tsunekawa
- Department of Ophthalmology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
| | - Toshiyuki Matsuura
- Department of Ophthalmology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
| | - Tsutomu Yasukawa
- Department of Ophthalmology, Nagoya City University School of Medicine, Nagoya 467-8601, Japan
| | - Takaaki Kondo
- Department of Radiological and Medical Laboratory Sciences, Nagoya University Graduate School of Medicine, Nagoya 461-8673, Japan
| | - Hiroko Terasaki
- Department of Ophthalmology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
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Relationship between Oxidative Stress, Circadian Rhythms, and AMD. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2015; 2016:7420637. [PMID: 26885250 PMCID: PMC4738726 DOI: 10.1155/2016/7420637] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Revised: 10/24/2015] [Accepted: 10/26/2015] [Indexed: 12/31/2022]
Abstract
This work reviews concepts regarding oxidative stress and the mechanisms by which endogenous and exogenous factors produce reactive oxygen species (ROS). It also surveys the relationships between oxidative stress, circadian rhythms, and retinal damage in humans, particularly those related to light and photodamage. In the first section, the production of ROS by different cell organelles and biomolecules and the antioxidant mechanisms that antagonize this damage are reviewed. The second section includes a brief review of circadian clocks and their relationship with the cellular redox state. In the third part of this work, the relationship between retinal damage and ROS is described. The last part of this work focuses on retinal degenerative pathology, age-related macular degeneration, and the relationships between this pathology, ROS, and light. Finally, the possible interactions between the retinal pigment epithelium (RPE), circadian rhythms, and this pathology are discussed.
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Perusek L, Sahu B, Parmar T, Maeno H, Arai E, Le YZ, Subauste CS, Chen Y, Palczewski K, Maeda A. Di-retinoid-pyridinium-ethanolamine (A2E) Accumulation and the Maintenance of the Visual Cycle Are Independent of Atg7-mediated Autophagy in the Retinal Pigmented Epithelium. J Biol Chem 2015; 290:29035-44. [PMID: 26468292 PMCID: PMC4661415 DOI: 10.1074/jbc.m115.682310] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Revised: 10/03/2015] [Indexed: 01/10/2023] Open
Abstract
Autophagy is an evolutionarily conserved catabolic mechanism that relieves cellular stress by removing/recycling damaged organelles and debris through the action of lysosomes. Compromised autophagy has been implicated in many neurodegenerative diseases, including retinal degeneration. Here we examined retinal phenotypes resulting from RPE-specific deletion of the autophagy regulatory gene Atg7 by generating Atg7(flox/flox);VMD2-rtTA-cre+ mice to determine whether autophagy is essential for RPE functions including retinoid recycling. Atg7-deficient RPE displayed abnormal morphology with increased RPE thickness, cellular debris and vacuole formation indicating that autophagy is important in maintaining RPE homeostasis. In contrast, 11-cis-retinal content, ERGs and retinal histology were normal in mice with Atg7-deficient RPE in both fasted and fed states. Because A2E accumulation in the RPE is associated with pathogenesis of both Stargardt disease and age-related macular degeneration (AMD) in humans, deletion of Abca4 was introduced into Atg7(flox/flox);VMD2-rtTA-cre+ mice to investigate the role of autophagy during A2E accumulation. Comparable A2E concentrations were detected in the eyes of 6-month-old mice with and without Atg7 from both Abca4(-/-) and Abca4(+/+) backgrounds. To identify other autophagy-related molecules involved in A2E accumulation, we performed gene expression array analysis on A2E-treated human RPE cells and found up-regulation of four autophagy related genes; DRAM1, NPC1, CASP3, and EIF2AK3/PERK. These observations indicate that Atg7-mediated autophagy is dispensable for retinoid recycling and A2E deposition; however, autophagy plays a role in coping with stress caused by A2E accumulation.
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Affiliation(s)
| | | | - Tanu Parmar
- From the Departments of Ophthalmology and Visual Sciences
| | - Hiroshi Maeno
- From the Departments of Ophthalmology and Visual Sciences
| | - Eisuke Arai
- From the Departments of Ophthalmology and Visual Sciences
| | - Yun-Zheng Le
- Departments of Medicine Endocrinology, Cell Biology, and Ophthalmology and Harold Hamm Diabetes Center, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104
| | - Carlos S Subauste
- Medicine, Case Western Reserve University, Cleveland, Ohio 44106 and
| | - Yu Chen
- Pharmacology and Cleveland Center for Membrane and Structural Biology, and
| | | | - Akiko Maeda
- From the Departments of Ophthalmology and Visual Sciences, Pharmacology and Cleveland Center for Membrane and Structural Biology, and
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35
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Protective effect of autophagy on human retinal pigment epithelial cells against lipofuscin fluorophore A2E: implications for age-related macular degeneration. Cell Death Dis 2015; 6:e1972. [PMID: 26561782 PMCID: PMC4670934 DOI: 10.1038/cddis.2015.330] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Revised: 10/03/2015] [Accepted: 10/06/2015] [Indexed: 12/12/2022]
Abstract
Age-related macular degeneration (AMD) is the leading cause of central vision loss in the elderly. Degeneration of retinal pigment epithelial (RPE) cells is a crucial causative factor responsible for the onset and progression of AMD. A2E, a major component of toxic lipofuscin implicated in AMD, is deposited in RPE cells with age. However, the mechanism whereby A2E may contribute to the pathogenesis of AMD remains unclear. We demonstrated that A2E was a danger signal of RPE cells, which induced autophagy and decreased cell viability in a concentration- and time-dependent manner. Within 15 min after the treatment of RPE with 25 μM A2E, the induction of autophagosome was detected by transmission electron microscopy. After continuous incubating RPE cells with A2E, intense punctate staining of LC3 and increased expression of LC3-II and Beclin-1 were identified. Meanwhile, the levels of intercellular adhesion molecule (ICAM), interleukin (IL)1β, IL2, IL-6, IL-8, IL-17A, IL-22, macrophage cationic peptide (MCP)-1, stromal cell-derived factor (SDF)-1, and vascular endothelial growth factor A (VEGFA) were elevated. The autophagic inhibitor 3-methyladenine (3-MA) and activator rapamycin were also used to verify the effect of autophagy on RPE cells against A2E. Our results revealed that 3-MA decreased the autophagosomes and LC3 puncta induced by A2E, increased inflammation-associated protein expression including ICAM, IL1β, IL2, IL-6, IL-8, IL-17A, IL-22, and SDF-1, and upregulated VEGFA expression. Whereas rapamycin augmented the A2E-mediated autophagy, attenuated protein expression of inflammation-associated and angiogenic factors, and blocked the Akt/mTOR pathway. Taken together, A2E induces autophagy in RPE cells at the early stage of incubation, and this autophagic response can be inhibited by 3-MA or augmented by rapamycin via the mTOR pathway. The enhancement of autophagy has a protective role in RPE cells against the adverse effects of A2E by reducing the secretion of inflammatory cytokines and VEGFA.
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