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Dieguez HH, Romeo HE, Alaimo A, Bernal Aguirre NA, Calanni JS, Adán Aréan JS, Alvarez S, Sciurano R, Rosenstein RE, Dorfman D. Mitochondrial quality control in non-exudative age-related macular degeneration: From molecular mechanisms to structural and functional recovery. Free Radic Biol Med 2024; 219:17-30. [PMID: 38579938 DOI: 10.1016/j.freeradbiomed.2024.03.024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/03/2024] [Revised: 03/22/2024] [Accepted: 03/28/2024] [Indexed: 04/07/2024]
Abstract
Non-exudative age-related macular degeneration (NE-AMD) is the leading blindness cause in the elderly. Clinical and experimental evidence supports that early alterations in macular retinal pigment epithelium (RPE) mitochondria play a key role in NE-AMD-induced damage. Mitochondrial dynamics (biogenesis, fusion, fission, and mitophagy), which is under the central control of AMP-activated kinase (AMPK), in turn, determines mitochondrial quality. We have developed a NE-AMD model in C57BL/6J mice induced by unilateral superior cervical ganglionectomy (SCGx), which progressively reproduces the disease hallmarks circumscribed to the temporal region of the RPE/outer retina that exhibits several characteristics of the human macula. In this work we have studied RPE mitochondrial structure, dynamics, function, and AMPK role on these parameters' regulation at the nasal and temporal RPE from control eyes and at an early stage of experimental NE-AMD (i.e., 4 weeks post-SCGx). Although RPE mitochondrial mass was preserved, their function, which was higher at the temporal than at the nasal RPE in control eyes, was significantly decreased at 4 weeks post-SCGx at the same region. Mitochondria were bigger, more elongated, and with denser cristae at the temporal RPE from control eyes. Exclusively at the temporal RPE, SCGx severely affected mitochondrial morphology and dynamics, together with the levels of phosphorylated AMPK (p-AMPK). AMPK activation with metformin restored RPE p-AMPK levels, and mitochondrial dynamics, structure, and function at 4 weeks post-SCGx, as well as visual function and RPE/outer retina structure at 10 weeks post-SCGx. These results demonstrate a key role of the temporal RPE mitochondrial homeostasis as an early target for NE-AMD-induced damage, and that pharmacological AMPK activation could preserve mitochondrial morphology, dynamics, and function, and, consequently, avoid the functional and structural damage induced by NE-AMD.
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Affiliation(s)
- Hernán H Dieguez
- Laboratory of Retinal Neurochemistry and Experimental Ophthalmology, Department of Human Biochemistry, School of Medicine/CEFyBO, University of Buenos Aires/CONICET, Buenos Aires, Argentina
| | - Horacio E Romeo
- School of Engineering and Agrarian Sciences, Pontifical Catholic University of Argentina, BIOMED/UCA/CONICET, Buenos Aires, Argentina
| | - Agustina Alaimo
- Interdisciplinary Laboratory of Cellular Dynamics and Nanotools, Department of Biological Chemistry, Faculty of Exact and Natural Sciences/IQUIBICEN, University of Buenos Aires/CONICET, Buenos Aires, Argentina
| | - Nathaly A Bernal Aguirre
- Laboratory of Retinal Neurochemistry and Experimental Ophthalmology, Department of Human Biochemistry, School of Medicine/CEFyBO, University of Buenos Aires/CONICET, Buenos Aires, Argentina
| | - Juan S Calanni
- Laboratory of Retinal Neurochemistry and Experimental Ophthalmology, Department of Human Biochemistry, School of Medicine/CEFyBO, University of Buenos Aires/CONICET, Buenos Aires, Argentina
| | - Juan S Adán Aréan
- Department of Analytical Chemistry and Physicochemistry, School of Pharmacy and Biochemistry/IBIMOL, University of Buenos Aires/CONICET, Buenos Aires, Argentina
| | - Silvia Alvarez
- Department of Analytical Chemistry and Physicochemistry, School of Pharmacy and Biochemistry/IBIMOL, University of Buenos Aires/CONICET, Buenos Aires, Argentina
| | - Roberta Sciurano
- Department of Cellular Biology, Histology, Embryology and Genetics, School of Medicine/INBIOMED, UBA/CONICET, Buenos Aires, Argentina
| | - Ruth E Rosenstein
- Laboratory of Retinal Neurochemistry and Experimental Ophthalmology, Department of Biological Chemistry, Faculty of Exact and Natural Sciences/IQUIBICEN, University of Buenos Aires, Buenos Aires, Argentina; Department of Human Biochemistry, School of Medicine, University of Buenos Aires, Buenos Aires, Argentina
| | - Damián Dorfman
- Laboratory of Retinal Neurochemistry and Experimental Ophthalmology, Department of Human Biochemistry, School of Medicine/CEFyBO, University of Buenos Aires/CONICET, Buenos Aires, Argentina.
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Chen M, Wang Y, Dalal R, Du J, Vollrath D. Alternative oxidase blunts pseudohypoxia and photoreceptor degeneration due to RPE mitochondrial dysfunction. Proc Natl Acad Sci U S A 2024; 121:e2402384121. [PMID: 38865272 PMCID: PMC11194566 DOI: 10.1073/pnas.2402384121] [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: 02/05/2024] [Accepted: 05/15/2024] [Indexed: 06/14/2024] Open
Abstract
Loss of mitochondrial electron transport complex (ETC) function in the retinal pigment epithelium (RPE) in vivo results in RPE dedifferentiation and progressive photoreceptor degeneration, and has been implicated in the pathogenesis of age-related macular degeneration. Xenogenic expression of alternative oxidases in mammalian cells and tissues mitigates phenotypes arising from some mitochondrial electron transport defects, but can exacerbate others. We expressed an alternative oxidase from Ciona intestinalis (AOX) in ETC-deficient murine RPE in vivo to assess the retinal consequences of stimulating coenzyme Q oxidation and respiration without ATP generation. RPE-restricted expression of AOX in this context is surprisingly beneficial. This focused intervention mitigates RPE mTORC1 activation, dedifferentiation, hypertrophy, stress marker expression, pseudohypoxia, and aerobic glycolysis. These RPE cell autonomous changes are accompanied by increased glucose delivery to photoreceptors with attendant improvements in photoreceptor structure and function. RPE-restricted AOX expression normalizes accumulated levels of succinate and 2-hydroxyglutarate in ETC-deficient RPE, and counteracts deficiencies in numerous neural retinal metabolites. These features can be attributed to the activation of mitochondrial inner membrane flavoproteins such as succinate dehydrogenase and proline dehydrogenase, and alleviation of inhibition of 2-oxyglutarate-dependent dioxygenases such as prolyl hydroxylases and epigenetic modifiers. Our work underscores the importance to outer retinal health of coenzyme Q oxidation in the RPE and identifies a metabolic network critical for photoreceptor survival in the context of RPE mitochondrial dysfunction.
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Affiliation(s)
- Ming Chen
- Department of Genetics, Stanford University School of Medicine, Palo Alto, CA94305
| | - Yekai Wang
- Department of Ophthalmology and Visual Sciences, West Virginia University, Morgantown, WV26506
- Department of Biochemistry and Molecular Medicine, West Virginia University, Morgantown, WV26506
| | - Roopa Dalal
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA94305
| | - Jianhai Du
- Department of Ophthalmology and Visual Sciences, West Virginia University, Morgantown, WV26506
- Department of Biochemistry and Molecular Medicine, West Virginia University, Morgantown, WV26506
| | - Douglas Vollrath
- Department of Genetics, Stanford University School of Medicine, Palo Alto, CA94305
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA94305
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3
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Jeong H, Shaia JK, Markle JC, Talcott KE, Singh RP. Melatonin and Risk of Age-Related Macular Degeneration. JAMA Ophthalmol 2024:2819801. [PMID: 38842832 PMCID: PMC11157446 DOI: 10.1001/jamaophthalmol.2024.1822] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Accepted: 04/15/2024] [Indexed: 06/07/2024]
Abstract
Importance Melatonin has been shown to oppose several processes that are known to mediate age-related macular degeneration (AMD), but whether melatonin can confer benefits against AMD remains unclear. Objective To examine the association between melatonin supplementation and the risk of the development or progression of AMD. Design, Setting, and Participants This retrospective cohort study accessed data from TriNetX, a national database of deidentified electronic medical records from both inpatient and outpatient health care organizations across the US, between December 4, 2023, and March 19, 2024. Patients aged 50 years or older, 60 years or older, and 70 years or older with no history of AMD (AMD-naive group) and with a history of nonexudative AMD (nonexudative AMD group) were queried for instances of melatonin medication codes between November 14, 2008, and November 14, 2023. Patients were then classified into either a melatonin group or a control group based on the presence of medication codes for melatonin. Propensity score matching (PSM) was performed to match the cohorts based on demographic variables, comorbidities, and nonmelatonin hypnotic medication use. Exposure The presence of at least 4 instances of melatonin records that each occurred at least 3 months apart. Main Outcomes and Measures After PSM, the melatonin and the control cohorts were compared to evaluate the risk ratios (RRs) and the 95% CIs of having an outcome. For the AMD-naive group, the outcome was defined as a new diagnosis of any AMD, whereas for the nonexudative AMD group, the outcome was progression to exudative AMD. Results Among 121 523 patients in the melatonin-naive group aged 50 years or older (4848 in the melatonin cohort [4580 after PSM; mean (SD) age, 68.24 (11.47) years; 2588 female (56.5%)] and 116 675 in the control cohort [4580 after PSM; mean (SD) age, 68.17 (10.63) years; 2681 female (58.5%)]), melatonin use was associated with a reduced risk of developing AMD (RR, 0.42; 95% CI, 0.28-0.62). Among 66 253 patients aged 50 years or older in the nonexudative AMD group (4350 in the melatonin cohort [4064 after PSM; mean (SD) age, 80.21 (8.78) years; 2482 female (61.1%)] and 61 903 in the control cohort [4064 patients after PSM; mean (SD) age, 80.31 (8.03) years; 2531 female (62.3%)]), melatonin was associated with a reduced risk of AMD progression to exudative AMD (RR, 0.44; 95% CI, 0.34-0.56). The results were consistent among subsets of individuals aged 60 years or older (AMD-naive cohort: RR, 0.36 [95% CI, 0.25-0.54]; nonexudative AMD cohort: RR, 0.38 [95% CI, 0.30-0.49]) and 70 years or older (AMD-naive cohort: RR, 0.35 [95% CI, 0.23-0.53]; nonexudative AMD cohort: RR, 0.40 [95% CI, 0.31-0.51]). Conclusions and Relevance Melatonin use was associated with a decreased risk of development and progression of AMD. Although lifestyle factors may have influenced this association, these findings provide a rationale for further research on the efficacy of using melatonin as a preventive therapy against AMD.
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Affiliation(s)
- Hejin Jeong
- Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Jacqueline K. Shaia
- Case Western Reserve University School of Medicine, Cleveland, Ohio
- Center for Ophthalmic Bioinformatics, Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio
| | - Jonathan C. Markle
- Center for Ophthalmic Bioinformatics, Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio
| | - Katherine E. Talcott
- Center for Ophthalmic Bioinformatics, Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio
| | - Rishi P. Singh
- Center for Ophthalmic Bioinformatics, Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio
- Cleveland Clinic Martin Health, Cleveland Clinic Florida, Stuart
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Xu Y, Tummala SR, Chen X, Vardi N. VDAC in Retinal Health and Disease. Biomolecules 2024; 14:654. [PMID: 38927058 PMCID: PMC11201675 DOI: 10.3390/biom14060654] [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: 04/18/2024] [Revised: 05/22/2024] [Accepted: 05/31/2024] [Indexed: 06/28/2024] Open
Abstract
The retina, a tissue of the central nervous system, is vital for vision as its photoreceptors capture light and transform it into electrical signals, which are further processed before they are sent to the brain to be interpreted as images. The retina is unique in that it is continuously exposed to light and has the highest metabolic rate and demand for energy amongst all the tissues in the body. Consequently, the retina is very susceptible to oxidative stress. VDAC, a pore in the outer membrane of mitochondria, shuttles metabolites between mitochondria and the cytosol and normally protects cells from oxidative damage, but when a cell's integrity is greatly compromised it initiates cell death. There are three isoforms of VDAC, and existing evidence indicates that all three are expressed in the retina. However, their precise localization and function in each cell type is unknown. It appears that most retinal cells express substantial amounts of VDAC2 and VDAC3, presumably to protect them from oxidative stress. Photoreceptors express VDAC2, HK2, and PKM2-key proteins in the Warburg pathway that also protect these cells. Consistent with its role in initiating cell death, VDAC is overexpressed in the retinal degenerative diseases retinitis pigmentosa, age related macular degeneration (AMD), and glaucoma. Treatment with antioxidants or inhibiting VDAC oligomerization reduced its expression and improved cell survival. Thus, VDAC may be a promising therapeutic candidate for the treatment of these diseases.
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Affiliation(s)
- Ying Xu
- Guangdong Key Laboratory of Non-Human Primate Research, Key Laboratory of CNS Regeneration (Ministry of Education), Guangdong-Hongkong-Macau Institute of CNS Regeneration, Jinan University, Guangzhou 510632, China; (Y.X.); (X.C.)
| | - Shanti R. Tummala
- Department of Pharmacology, University of Pennsylvania, Philadelphia, PA 19104, USA;
| | - Xiongmin Chen
- Guangdong Key Laboratory of Non-Human Primate Research, Key Laboratory of CNS Regeneration (Ministry of Education), Guangdong-Hongkong-Macau Institute of CNS Regeneration, Jinan University, Guangzhou 510632, China; (Y.X.); (X.C.)
| | - Noga Vardi
- Department of Neuroscience, University of Pennsylvania, Philadelphia, PA 19104, USA
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5
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Zhang CJ, Mou H, Yuan J, Wang YH, Sun SN, Wang W, Xu ZH, Yu SJ, Jin K, Jin ZB. Effects of fluorescent protein tdTomato on mouse retina. Exp Eye Res 2024; 243:109910. [PMID: 38663720 DOI: 10.1016/j.exer.2024.109910] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 02/26/2024] [Accepted: 04/22/2024] [Indexed: 04/30/2024]
Abstract
Fluorescent proteins (FPs) have been widely used to investigate cellular and molecular interactions and trace biological events in many applications. Some of the FPs have been demonstrated to cause undesirable cellular damage by light-induced ROS production in vivo or in vitro. However, it remains unknown if one of the most popular FPs, tdTomato, has similar effects in neuronal cells. In this study, we discovered that tdTomato expression led to unexpected retinal dysfunction and ultrastructural defects in the transgenic mouse retina. The retinal dysfunction mainly manifested in the reduced photopic electroretinogram (ERG) responses and decreased contrast sensitivity in visual acuity, caused by mitochondrial damages characterized with cellular redistribution, morphological modifications and molecular profiling alterations. Taken together, our findings for the first time demonstrated the retinal dysfunction and ultrastructural defects in the retinas of tdTomato-transgenic mice, calling for a more careful design and interpretation of experiments involved in FPs.
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Affiliation(s)
- Chang-Jun Zhang
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Science Key Laboratory, Beijing, 100730, China
| | - Hao Mou
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Science Key Laboratory, Beijing, 100730, China
| | - Jing Yuan
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Science Key Laboratory, Beijing, 100730, China
| | - Ya-Han Wang
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Science Key Laboratory, Beijing, 100730, China
| | - Shu-Ning Sun
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Science Key Laboratory, Beijing, 100730, China
| | - Wen Wang
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Science Key Laboratory, Beijing, 100730, China
| | - Ze-Hua Xu
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Science Key Laboratory, Beijing, 100730, China
| | - Si-Jian Yu
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Science Key Laboratory, Beijing, 100730, China
| | - Kangxin Jin
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Science Key Laboratory, Beijing, 100730, China.
| | - Zi-Bing Jin
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Science Key Laboratory, Beijing, 100730, China.
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6
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Yu Y, Wang G, Liu Y, Meng Z. Potential application of traditional Chinese medicine in age-related macular degeneration-focusing on mitophagy. Front Pharmacol 2024; 15:1410998. [PMID: 38828456 PMCID: PMC11140084 DOI: 10.3389/fphar.2024.1410998] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2024] [Accepted: 04/30/2024] [Indexed: 06/05/2024] Open
Abstract
Retinal pigment epithelial cell and neuroretinal damage in age-related macular degeneration (AMD) can lead to serious visual impairments and blindness. Studies have shown that mitophagy, a highly specialized cellular degradation system, is implicated in the pathogenesis of AMD. Mitophagy selectively eliminates impaired or non-functioning mitochondria via several pathways, such as the phosphatase and tensin homolog-induced kinase 1/Parkin, BCL2-interacting protein 3 and NIP3-like protein X, FUN14 domain-containing 1, and AMP-activated protein kinase pathways. This has a major impact on the maintenance of mitochondrial homeostasis. Therefore, the regulation of mitophagy could be a promising therapeutic strategy for AMD. Traditional Chinese medicine (TCM) uses natural products that could potentially prevent and treat various diseases, such as AMD. This review aims to summarize recent findings on mitophagy regulation pathways and the latest progress in AMD treatment targeting mitophagy, emphasizing methods involving TCM.
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Affiliation(s)
- Yujia Yu
- First Clinical Medical School, Shandong University of Traditional Chinese Medicine, Jinan, Shandong, China
| | - Gaofeng Wang
- Affiliated Hospital of Shandong University of Traditional Chinese Medicine, Shandong Province Hospital of Traditional Chinese Medicine, Jinan, Shandong, China
| | - Yong Liu
- Affiliated Hospital of Shandong University of Traditional Chinese Medicine, Shandong Province Hospital of Traditional Chinese Medicine, Jinan, Shandong, China
| | - Zhaoru Meng
- School of Engineering, The Hong Kong University of Science and Technology, Kowloon, Hong Kong SAR, China
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7
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Faura G, Studenovska H, Sekac D, Ellederova Z, Petrovski G, Eide L. The Effects of the Coating and Aging of Biodegradable Polylactic Acid Membranes on In Vitro Primary Human Retinal Pigment Epithelium Cells. Biomedicines 2024; 12:966. [PMID: 38790928 PMCID: PMC11117638 DOI: 10.3390/biomedicines12050966] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2024] [Revised: 04/17/2024] [Accepted: 04/24/2024] [Indexed: 05/26/2024] Open
Abstract
Age-related macular degeneration (AMD) is the most frequent cause of blindness in developed countries. The replacement of dysfunctional human retinal pigment epithelium (hRPE) cells by the transplantation of in vitro-cultivated hRPE cells to the affected area emerges as a feasible strategy for regenerative therapy. Synthetic biomimetic membranes arise as powerful hRPE cell carriers, but as biodegradability is a requirement, it also poses a challenge due to its limited durability. hRPE cells exhibit several characteristics that putatively respond to the type of membrane carrier, and they can be used as biomarkers to evaluate and further optimize such membranes. Here, we analyze the pigmentation, transepithelial resistance, genome integrity, and maturation markers of hRPE cells plated on commercial polycarbonate (PC) versus in-house electrospun polylactide-based (PLA) membranes, both enabling separate apical/basolateral compartments. Our results show that PLA is superior to PC-based membranes for the cultivation of hRPEs, and the BEST1/RPE65 maturation markers emerge as the best biomarkers for addressing the quality of hRPE cultivated in vitro. The stability of the cultures was observed to be affected by PLA aging, which is an effect that could be partially palliated by the coating of the PLA membranes.
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Affiliation(s)
- Georgina Faura
- Department of Medical Biochemistry, Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, 0372 Oslo, Norway
- CIDETEC, Basque Research and Technology Alliance (BRTA), 20014 Donostia-San Sebastián, Spain
| | - Hana Studenovska
- Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, 162 00 Prague, Czech Republic;
| | - David Sekac
- Institute of Animal Physiology and Genetics, Academy of Sciences of the Czech Republic, 277 21 Libechov, Czech Republic; (D.S.); (Z.E.)
- Department of Cell Biology, Faculty of Science, Charles University, 128 00 Prague, Czech Republic
| | - Zdenka Ellederova
- Institute of Animal Physiology and Genetics, Academy of Sciences of the Czech Republic, 277 21 Libechov, Czech Republic; (D.S.); (Z.E.)
| | - Goran Petrovski
- Center for Eye Research and Innovative Diagnostics, Department of Ophthalmology, Oslo University Hospital and Institute for Clinical Medicine, University of Oslo, 0424 Oslo, Norway;
- Norwegian Center for Stem Cell Research, Oslo University Hospital, 0424 Oslo, Norway
- Department of Ophthalmology, University Hospital Centre, University of Split School of Medicine, 21000 Split, Croatia
- UKLO Network, University St. Kliment Ohridski, 7000 Bitola, North Macedonia
| | - Lars Eide
- Department of Medical Biochemistry, Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, 0372 Oslo, Norway
- Department of Medical Biochemistry, Oslo University Hospital, 0424 Oslo, Norway
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8
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Liu D, Liu Z, Liao H, Chen ZS, Qin B. Ferroptosis as a potential therapeutic target for age-related macular degeneration. Drug Discov Today 2024; 29:103920. [PMID: 38369100 DOI: 10.1016/j.drudis.2024.103920] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Revised: 02/11/2024] [Accepted: 02/14/2024] [Indexed: 02/20/2024]
Abstract
Cell death plays a crucial part in the process of age-related macular degeneration (AMD), but its mechanisms remain elusive. Accumulating evidence suggests that ferroptosis, a novel form of regulatory cell death characterized by iron-dependent accumulation of lipid hydroperoxides, has a crucial role in the pathogenesis of AMD. Numerous studies have suggested that ferroptosis participates in the degradation of retinal cells and accelerates the progression of AMD. Furthermore, inhibitors of ferroptosis exhibit notable protective effects in AMD, underscoring the significance of ferroptosis as a pivotal mechanism in the death of retinal cells during the process of AMD. This review aims to summarize the molecular mechanisms of ferroptosis in AMD, enumerate potential inhibitors and discuss the challenges and future opportunities associated with targeting ferroptosis as a therapeutic strategy, providing important information references and insights for the prevention and treatment of AMD.
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Affiliation(s)
- Dongcheng Liu
- Shenzhen Aier Eye Hospital, Aier Eye Hospital, Jinan University, Shenzhen, China; Shenzhen Aier Ophthalmic Technology Institute, Shenzhen, China
| | - Ziling Liu
- Shenzhen Aier Eye Hospital, Aier Eye Hospital, Jinan University, Shenzhen, China; Shenzhen Aier Ophthalmic Technology Institute, Shenzhen, China
| | - Hongxia Liao
- Shenzhen Aier Eye Hospital, Aier Eye Hospital, Jinan University, Shenzhen, China; Shenzhen Aier Ophthalmic Technology Institute, Shenzhen, China
| | - Zhe-Sheng Chen
- College of Pharmacy and Health Sciences, St. John's University, Queens, New York, USA.
| | - Bo Qin
- Shenzhen Aier Eye Hospital, Aier Eye Hospital, Jinan University, Shenzhen, China; Shenzhen Aier Ophthalmic Technology Institute, Shenzhen, China; Aier Eye Hospital, Tianjin University, Tianjin, China.
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9
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Gurubaran IS. Mitochondrial damage and clearance in retinal pigment epithelial cells. Acta Ophthalmol 2024; 102 Suppl 282:3-53. [PMID: 38467968 DOI: 10.1111/aos.16661] [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: 01/24/2024] [Accepted: 01/31/2024] [Indexed: 03/13/2024]
Abstract
Age-related macular degeneration (AMD) is a devastating eye disease that causes permanent vision loss in the central part of the retina, known as the macula. Patients with such severe visual loss face a reduced quality of life and are at a 1.5 times greater risk of death compared to the general population. Currently, there is no cure for or effective treatment for dry AMD. There are several mechanisms thought to underlie the disease, for example, ageing-associated chronic oxidative stress, mitochondrial damage, harmful protein aggregation and inflammation. As a way of gaining a better understanding of the molecular mechanisms behind AMD and thus developing new therapies, we have created a peroxisome proliferator-activated receptor gamma coactivator 1-alpha and nuclear factor erythroid 2-related factor 2 (PGC1α/NFE2L2) double-knockout (dKO) mouse model that mimics many of the clinical features of dry AMD, including elevated levels of oxidative stress markers, damaged mitochondria, accumulating lysosomal lipofuscin and extracellular drusen-like structures in retinal pigment epithelial cells (RPE). In addition, a human RPE cell-based model was established to examine the impact of non-functional intracellular clearance systems on inflammasome activation. In this study, we found that there was a disturbance in the autolysosomal machinery responsible for clearing mitochondria in the RPE cells of one-year-old PGC1α/NFE2L2-deficient mice. The confocal immunohistochemical analysis revealed an increase in autophagosome marker microtubule-associated proteins 1A/1B light chain 3B (LC3B) as well as multiple mitophagy markers such as PTE-induced putative kinase 1 (PINK1) and E3 ubiquitin ligase (PARKIN), along with signs of damaged mitochondria. However, no increase in autolysosome formation was detected, nor was there a colocalization of the lysosomal marker LAMP2 or the mitochondrial marker, ATP synthase β. There was an upregulation of late autolysosomal fusion Ras-related protein (Rab7) in the perinuclear space of RPE cells, together with autofluorescent aggregates. Additionally, we observed an increase in the numbers of Toll-like receptors 3 and 9, while those of NOD-like receptor 3 were decreased in PGC1α/NFE2L2 dKO retinal specimens compared to wild-type animals. There was a trend towards increased complement component C5a and increased involvement of the serine protease enzyme, thrombin, in enhancing the terminal pathway producing C5a, independent of C3. The levels of primary acute phase C-reactive protein and receptor for advanced glycation end products were also increased in the PGC1α/NFE2L2 dKO retina. Furthermore, selective proteasome inhibition with epoxomicin promoted both nicotinamide adenine dinucleotide phosphate (NADPH) oxidase and mitochondrial-mediated oxidative stress, leading to the release of mitochondrial DNA to the cytosol, resulting in potassium efflux-dependent activation of the absent in melanoma 2 (AIM2) inflammasome and the subsequent secretion of interleukin-1β in ARPE-19 cells. In conclusion, the data suggest that there is at least a relative decrease in mitophagy, increases in the amounts of C5 and thrombin and decreased C3 levels in this dry AMD-like model. Moreover, selective proteasome inhibition evoked mitochondrial damage and AIM2 inflammasome activation in ARPE-19 cells.
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Affiliation(s)
- Iswariyaraja Sridevi Gurubaran
- Department of Medicine, Clinical Medicine Unit, University of Eastern Finland Institute of Clinical Medicine, Kuopio, Northern Savonia, Finland
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10
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Landowski M, Gogoi P, Ikeda S, Ikeda A. Roles of transmembrane protein 135 in mitochondrial and peroxisomal functions - implications for age-related retinal disease. FRONTIERS IN OPHTHALMOLOGY 2024; 4:1355379. [PMID: 38576540 PMCID: PMC10993500 DOI: 10.3389/fopht.2024.1355379] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/06/2024]
Abstract
Aging is the most significant risk factor for age-related diseases in general, which is true for age-related diseases in the eye including age-related macular degeneration (AMD). Therefore, in order to identify potential therapeutic targets for these diseases, it is crucial to understand the normal aging process and how its mis-regulation could cause age-related diseases at the molecular level. Recently, abnormal lipid metabolism has emerged as one major aspect of age-related symptoms in the retina. Animal models provide excellent means to identify and study factors that regulate lipid metabolism in relation to age-related symptoms. Central to this review is the role of transmembrane protein 135 (TMEM135) in the retina. TMEM135 was identified through the characterization of a mutant mouse strain exhibiting accelerated retinal aging and positional cloning of the responsible mutation within the gene, indicating the crucial role of TMEM135 in regulating the normal aging process in the retina. Over the past decade, the molecular functions of TMEM135 have been explored in various models and tissues, providing insights into the regulation of metabolism, particularly lipid metabolism, through its action in multiple organelles. Studies indicated that TMEM135 is a significant regulator of peroxisomes, mitochondria, and their interaction. Here, we provide an overview of the molecular functions of TMEM135 which is crucial for regulating mitochondria, peroxisomes, and lipids. The review also discusses the age-dependent phenotypes in mice with TMEM135 perturbations, emphasizing the importance of a balanced TMEM135 function for the health of the retina and other tissues including the heart, liver, and adipose tissue. Finally, we explore the potential roles of TMEM135 in human age-related retinal diseases, connecting its functions to the pathobiology of AMD.
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Affiliation(s)
- Michael Landowski
- Department of Medical Genetics, University of Wisconsin-Madison, Madison, WI, United States
- McPherson Eye Research Institute, University of Wisconsin-Madison, Madison, WI, United States
| | - Purnima Gogoi
- Department of Medical Genetics, University of Wisconsin-Madison, Madison, WI, United States
| | - Sakae Ikeda
- Department of Medical Genetics, University of Wisconsin-Madison, Madison, WI, United States
- McPherson Eye Research Institute, University of Wisconsin-Madison, Madison, WI, United States
| | - Akihiro Ikeda
- Department of Medical Genetics, University of Wisconsin-Madison, Madison, WI, United States
- McPherson Eye Research Institute, University of Wisconsin-Madison, Madison, WI, United States
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11
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Chang YY, Wang M, Yeh JH, Tsou SC, Chen TC, Hsu MY, Lee YJ, Wang I, Lin HW. The protective effects of beta-mangostin against sodium iodate-induced retinal ROS-mediated apoptosis through MEK/ERK and p53 signaling pathways. Food Funct 2023; 14:10896-10909. [PMID: 37990840 DOI: 10.1039/d3fo03568a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2023]
Abstract
Previous studies have indicated that NaIO3 induces intracellular reactive oxygen species (ROS) production and has been used as a model for age-related macular degeneration (AMD) due to the selective retinal pigment epithelium (RPE) cell damage it induces. Beta-mangostin (BM) is a xanthone-type natural compound isolated from Cratoxylum arborescens. The influence of BM on NaIO3-induced oxidative stress damage in ARPE-19 cells has not yet been elucidated. In this study, we investigated how BM protects ARPE-19 cells from NaIO3-induced ROS-mediated apoptosis. Our results revealed that BM notably improved cell viability and prevented ARPE-19 cell mitochondrial dysfunction mediated-apoptosis induced by NaIO3; it was mediated by significantly reduced NaIO3-upregulated ROS, cellular H2O2 production and improved downregulated glutathione and catalase activities. Furthermore, we found that BM could suppress the expression of Bax, cleaved PARP, and cleaved caspase-3 by decreasing phosphorylation of MEK/ERK and p53 expression in NaIO3-induced ARPE-19 cells. At the same time, we also used MEK inhibitors (PD98059) to confirm the above phenomenon. Moreover, our animal experiments revealed that BM prevented NaIO3 from causing retinal deformation; it led to thicker outer and inner nuclear layers and downregulated cleaved caspase-3 expression compared to the group receiving NaIO3 only. Collectively, these results suggest that BM can protect the RPE and retina from NaIO3-induced apoptosis through ROS-mediated mitochondrial dysfunction involving the MEK/ERK and p53 signaling pathways.
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Affiliation(s)
- Yuan-Yen Chang
- Department of Microbiology and Immunology, School of Medicine, Chung Shan Medical University and Clinical Laboratory, Chung Shan Medical University Hospital, Taichung 40201, Taiwan
| | - Meilin Wang
- Department of Microbiology and Immunology, School of Medicine, Chung Shan Medical University and Clinical Laboratory, Chung Shan Medical University Hospital, Taichung 40201, Taiwan
| | - Jui-Hsuan Yeh
- Institute of Medicine, Chung Shan Medical University, Taichung 40201, Taiwan
| | - Shang-Chun Tsou
- Department of Nutrition, Chung Shan Medical University, Taichung 40201, Taiwan
| | - Tzu-Chun Chen
- Institute of Medicine, Chung Shan Medical University, Taichung 40201, Taiwan
| | - Min-Yen Hsu
- School of Medicine, Chung Shan Medical University and Department of Ophthalmology, Chung Shan Medical University Hospital, Taichung 40201, Taiwan
| | - Yi-Ju Lee
- Department of Pathology, Chung Shan Medical University, Chung Shan Medical University Hospital, Taichung 40201, Taiwan
| | - Inga Wang
- Rehabilitation Sciences & Technology, University of Wisconsin-Milwaukee, Milwaukee, WI, USA
| | - Hui-Wen Lin
- Department of Optometry, Asia University, Taichung 41354, Taiwan.
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12
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Davidescu M, Mezzasoma L, Fettucciari K, Pascucci L, Pariano M, Di Michele A, Bereshchenko O, Cagini C, Cellini B, Corazzi L, Bellezza I, Macchioni L. Cardiolipin-mediated temporal response to hydroquinone toxicity in human retinal pigmented epithelial cell line. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2023; 1870:119554. [PMID: 37524263 DOI: 10.1016/j.bbamcr.2023.119554] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 07/13/2023] [Accepted: 07/27/2023] [Indexed: 08/02/2023]
Abstract
Hydroquinone, a potent toxic agent of cigarette smoke, damages retinal pigmented epithelial cells by triggering oxidative stress and mitochondrial dysfunction, two events causally related to the development and progression of retinal diseases. The inner mitochondrial membrane is enriched in cardiolipin, a phospholipid susceptible of oxidative modifications which determine cell-fate decision. Using ARPE-19 cell line as a model of retinal pigmented epithelium, we analyzed the potential involvement of cardiolipin in hydroquinone toxicity. Hydroquinone exposure caused an early concentration-dependent increase in mitochondrial reactive oxygen species, decrease in mitochondrial membrane potential, and rise in the rate of oxygen consumption not accompanied by changes in ATP levels. Despite mitochondrial impairment, cell viability was preserved. Hydroquinone induced cardiolipin translocation to the outer mitochondrial membrane, and an increase in the colocalization of the autophagosome adapter protein LC3 with mitochondria, indicating the induction of protective mitophagy. A prolonged hydroquinone treatment induced pyroptotic cell death by cardiolipin-mediated caspase-1 and gasdermin-D activation. Cardiolipin-specific antioxidants counteracted hydroquinone effects pointing out that cardiolipin can act as a mitochondrial "eat-me signal" or as a pyroptotic cell death trigger. Our results indicate that cardiolipin may act as a timer for the mitophagy to pyroptosis switch and propose cardiolipin-targeting compounds as promising approaches for the treatment of oxidative stress-related retinal diseases.
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Affiliation(s)
- Magdalena Davidescu
- Department of Medicine and Surgery, University of Perugia, P.le L. Severi 1, Perugia 06132, Italy
| | - Letizia Mezzasoma
- Department of Medicine and Surgery, University of Perugia, P.le L. Severi 1, Perugia 06132, Italy
| | - Katia Fettucciari
- Department of Medicine and Surgery, University of Perugia, P.le L. Severi 1, Perugia 06132, Italy
| | - Luisa Pascucci
- Department of Veterinary Medicine, University of Perugia, Via S. Costanzo 4, 06126 Perugia, Italy
| | - Marilena Pariano
- Department of Medicine and Surgery, University of Perugia, P.le L. Severi 1, Perugia 06132, Italy
| | - Alessandro Di Michele
- Department of Physic and Geology, University of Perugia, Via Pascoli, Perugia 06123, Italy
| | - Oxana Bereshchenko
- Department of Philosophy, Social Sciences, Humanities and Education, University of Perugia, Piazza Ermini 1, Perugia 06123, Italy
| | - Carlo Cagini
- Department of Medicine and Surgery, University of Perugia, P.le L. Severi 1, Perugia 06132, Italy
| | - Barbara Cellini
- Department of Medicine and Surgery, University of Perugia, P.le L. Severi 1, Perugia 06132, Italy
| | - Lanfranco Corazzi
- Department of Medicine and Surgery, University of Perugia, P.le L. Severi 1, Perugia 06132, Italy
| | - Ilaria Bellezza
- Department of Medicine and Surgery, University of Perugia, P.le L. Severi 1, Perugia 06132, Italy
| | - Lara Macchioni
- Department of Medicine and Surgery, University of Perugia, P.le L. Severi 1, Perugia 06132, Italy.
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13
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Li SY, Xue RY, Wu H, Pu N, Wei D, Zhao N, Song ZM, Tao Y. Novel Role of Molecular Hydrogen: The End of Ophthalmic Diseases? Pharmaceuticals (Basel) 2023; 16:1567. [PMID: 38004433 PMCID: PMC10674431 DOI: 10.3390/ph16111567] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 10/03/2023] [Accepted: 10/06/2023] [Indexed: 11/26/2023] Open
Abstract
Molecular hydrogen (H2) is a colorless, odorless, and tasteless gas which displays non-toxic features at high concentrations. H2 can alleviate oxidative damage, reduce inflammatory reactions and inhibit apoptosis cascades, thereby inducing protective and repairing effects on cells. H2 can be transported into the body in the form of H2 gas, hydrogen-rich water (HRW), hydrogen-rich saline (HRS) or H2 produced by intestinal bacteria. Accumulating evidence suggest that H2 is protective against multiple ophthalmic diseases, including cataracts, dry eye disease, diabetic retinopathy (DR) and other fields. In particular, H2 has been tested in the treatment of dry eye disease and corneal endothelial injury in clinical practice. This medical gas has brought hope to patients suffering from blindness. Although H2 has demonstrated promising therapeutic potentials and broad application prospects, further large-scale studies involving more patients are still needed to determine its optimal application mode and dosage. In this paper, we have reviewed the basic characteristics of H2, and its therapeutic effects in ophthalmic diseases. We also focus on the latest progress in the administration approaches and mechanisms underlying these benefits.
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Affiliation(s)
| | | | | | | | | | | | - Zong-Ming Song
- Henan Eye Institute, Henan Eye Hospital, People’s Hospital of Zhengzhou University, Henan Provincial People’s Hospital, Zhengzhou 450003, China
| | - Ye Tao
- Henan Eye Institute, Henan Eye Hospital, People’s Hospital of Zhengzhou University, Henan Provincial People’s Hospital, Zhengzhou 450003, China
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14
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Brooks CD, Kodati B, Stankowska DL, Krishnamoorthy RR. Role of mitophagy in ocular neurodegeneration. Front Neurosci 2023; 17:1299552. [PMID: 37965225 PMCID: PMC10641468 DOI: 10.3389/fnins.2023.1299552] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Accepted: 10/12/2023] [Indexed: 11/16/2023] Open
Abstract
Neurons in the central nervous system are among the most metabolically active cells in the body, characterized by high oxygen consumption utilizing glucose both aerobically and anaerobically. Neurons have an abundance of mitochondria which generate adequate ATP to keep up with the high metabolic demand. One consequence of the oxidative phosphorylation mechanism of ATP synthesis, is the generation of reactive oxygen species which produces cellular injury as well as damage to mitochondria. Mitochondria respond to injury by fusion which serves to ameliorate the damage through genetic complementation. Mitochondria also undergo fission to meet an increased energy demand. Loss of mitochondria is also compensated by increased biogenesis to generate new mitochondria. Damaged mitochondria are removed by mitophagy, an autophagic process, in which damaged mitochondria are surrounded by a membrane to form an autophagosome which ultimately fuses with the lysosome resulting in degradation of faulty mitochondria. Dysregulation of mitophagy has been reported in several central nervous system disorders, including, Alzheimer's disease and Parkinson's disease. Recent studies point to aberrant mitophagy in ocular neurodegenerative disorders which could be an important contributor to the disease etiology/pathology. This review article highlights some of the recent findings that point to dysregulation of mitophagy and it's underlying mechanisms in ocular neurodegenerative diseases, including, glaucoma, age-related macular degeneration and diabetic retinopathy.
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Affiliation(s)
- Calvin D. Brooks
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, TX, United States
- North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, TX, United States
| | - Bindu Kodati
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, TX, United States
- North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, TX, United States
| | - Dorota L. Stankowska
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, TX, United States
- North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, TX, United States
| | - Raghu R. Krishnamoorthy
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, TX, United States
- North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, TX, United States
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15
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Jiménez-Loygorri JI, Benítez-Fernández R, Viedma-Poyatos Á, Zapata-Muñoz J, Villarejo-Zori B, Gómez-Sintes R, Boya P. Mitophagy in the retina: Viewing mitochondrial homeostasis through a new lens. Prog Retin Eye Res 2023; 96:101205. [PMID: 37454969 DOI: 10.1016/j.preteyeres.2023.101205] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 07/11/2023] [Accepted: 07/13/2023] [Indexed: 07/18/2023]
Abstract
Mitochondrial function is key to support metabolism and homeostasis in the retina, an organ that has one of the highest metabolic rates body-wide and is constantly exposed to photooxidative damage and external stressors. Mitophagy is the selective autophagic degradation of mitochondria within lysosomes, and can be triggered by distinct stimuli such as mitochondrial damage or hypoxia. Here, we review the importance of mitophagy in retinal physiology and pathology. In the developing retina, mitophagy is essential for metabolic reprogramming and differentiation of retina ganglion cells (RGCs). In basal conditions, mitophagy acts as a quality control mechanism, maintaining a healthy mitochondrial pool to meet cellular demands. We summarize the different autophagy- and mitophagy-deficient mouse models described in the literature, and discuss the potential role of mitophagy dysregulation in retinal diseases such as glaucoma, diabetic retinopathy, retinitis pigmentosa, and age-related macular degeneration. Finally, we provide an overview of methods used to monitor mitophagy in vitro, ex vivo, and in vivo. This review highlights the important role of mitophagy in sustaining visual function, and its potential as a putative therapeutic target for retinal and other diseases.
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Affiliation(s)
- Juan Ignacio Jiménez-Loygorri
- Autophagy Lab, Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas Margarita Salas, CSIC, Ramiro de Maeztu 9, 28040, Madrid, Spain.
| | - Rocío Benítez-Fernández
- Autophagy Lab, Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas Margarita Salas, CSIC, Ramiro de Maeztu 9, 28040, Madrid, Spain; Departament of Neuroscience and Movement Science, Faculty of Science and Medicine, University of Fribourg, 1700, Fribourg, Switzerland
| | - Álvaro Viedma-Poyatos
- Autophagy Lab, Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas Margarita Salas, CSIC, Ramiro de Maeztu 9, 28040, Madrid, Spain
| | - Juan Zapata-Muñoz
- Autophagy Lab, Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas Margarita Salas, CSIC, Ramiro de Maeztu 9, 28040, Madrid, Spain
| | - Beatriz Villarejo-Zori
- Autophagy Lab, Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas Margarita Salas, CSIC, Ramiro de Maeztu 9, 28040, Madrid, Spain
| | - Raquel Gómez-Sintes
- Autophagy Lab, Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas Margarita Salas, CSIC, Ramiro de Maeztu 9, 28040, Madrid, Spain
| | - Patricia Boya
- Autophagy Lab, Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas Margarita Salas, CSIC, Ramiro de Maeztu 9, 28040, Madrid, Spain; Departament of Neuroscience and Movement Science, Faculty of Science and Medicine, University of Fribourg, 1700, Fribourg, Switzerland.
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16
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Rickabaugh E, Weatherston D, Harris TI, Jones JA, Vargis E. Engineering a Biomimetic In Vitro Model of Bruch's Membrane Using Hagfish Slime Intermediate Filament Proteins. ACS Biomater Sci Eng 2023; 9:5051-5061. [PMID: 37458693 DOI: 10.1021/acsbiomaterials.3c00411] [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: 08/15/2023]
Abstract
Bruch's membrane resides in the subretinal tissue and regulates the flow of nutrients and waste between the retinal pigment epithelial (RPE) and vascular layers of the eye. With age, Bruch's membrane becomes thicker, stiffer, and less permeable, which impedes its function as a boundary layer in the subretina. These changes contribute to pathologies such as age-related macular degeneration (AMD). To better understand how aging in Bruch's membrane affects surrounding tissues and to determine the relationship between aging and disease, an in vitro model of Bruch's membrane is needed. An accurate model of Bruch's membrane must be a proteinaceous, semipermeable, and nonporous biomaterial with similar mechanical properties to in vivo conditions. Additionally, this model must support RPE cell growth. While models of subretinal tissue exist, they typically differ from in vivo Bruch's membrane in one or more of these properties. This study evaluates the capability of membranes created from recombinant hagfish intermediate filament (rHIF) proteins to accurately replicate Bruch's membrane in an in vitro model of the subretinal tissue. The physical characteristics of these rHIF membranes were evaluated using mechanical testing, permeability assays, brightfield microscopy, and scanning electron microscopy. The capacity of the membranes to support RPE cell culture was determined using brightfield and fluorescent microscopy, as well as immunocytochemical staining. This study demonstrates that rHIF protein membranes are an appropriate biomaterial to accurately mimic both healthy and aged Bruch's membrane for in vitro modeling of the subretinal tissue.
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Affiliation(s)
- Emilee Rickabaugh
- Department of Biological Engineering, Utah State University, 4105 Old Main Hill, Logan, Utah 84322-4105 United States
| | - Dillon Weatherston
- Department of Biological Engineering, Utah State University, 4105 Old Main Hill, Logan, Utah 84322-4105 United States
| | - Thomas I Harris
- Department of Biology, Utah State University, 5305 Old Main Hill, Logan, Utah 84322-5305, United States
| | - Justin A Jones
- Department of Biology, Utah State University, 5305 Old Main Hill, Logan, Utah 84322-5305, United States
| | - Elizabeth Vargis
- Department of Biological Engineering, Utah State University, 4105 Old Main Hill, Logan, Utah 84322-4105 United States
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17
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Ishii M, Rohrer B. Anaphylatoxin C5a receptor signaling induces mitochondrial fusion and sensitizes retinal pigment epithelial cells to oxidative stress. Biochim Biophys Acta Gen Subj 2023; 1867:130374. [PMID: 37187450 PMCID: PMC10330548 DOI: 10.1016/j.bbagen.2023.130374] [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: 02/13/2023] [Revised: 04/20/2023] [Accepted: 04/26/2023] [Indexed: 05/17/2023]
Abstract
Mitochondrial dynamics is a morphological balance between fragmented and elongated shapes, reflecting mitochondrial metabolic status, cellular damage, and mitochondrial dysfunction. The anaphylatoxin C5a derived from complement component 5 cleavage, enhances cellular responses involved in pathological stimulation, innate immune responses, and host defense. However, the specific response of C5a and its receptor, C5a receptor (C5aR), in mitochondria is unclear. Here, we tested whether the C5a/C5aR signaling axis affects mitochondrial morphology in human-derived retinal pigment epithelial cell monolayers (ARPE-19). C5aR activation with the C5a polypeptide induced mitochondrial elongation. In contrast, oxidatively stressed cells (H2O2) responded to C5a with an enhancement of mitochondrial fragmentation and an increase in the number of pyknotic nuclei. C5a/C5aR signaling increased the expression of mitochondrial fusion-related protein, mitofusin-1 (MFN1) and - 2 (MFN2), as well as enhanced optic atrophy-1 (Opa1) cleavage, which are required for mitochondrial fusion events, whereas the mitochondrial fission protein, dynamin-related protein-1 (Drp1), and mitogen-activated protein kinase (MAPK)-dependent extracellular signal-regulated protein kinase (Erk1/2) phosphorylation were not affected. Moreover, C5aR activation increased the frequency of endoplasmic reticulum (ER)-mitochondria contacts. Finally, oxidative stress induced in a single cell within an RPE monolayer (488 nm blue laser spot stimulation) induced a bystander effect of mitochondrial fragmentation in adjacent surrounding cells only in C5a-treated monolayers. These results suggest that C5a/C5aR signaling produced an intermediate state, characterized by increased mitochondrial fusion and ER-mitochondrial contacts, that sensitizes cells to oxidative stress, leading to mitochondrial fragmentation and cell death.
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Affiliation(s)
- Masaaki Ishii
- Department of Ophthalmology, Medical University of South Carolina, Charleston, SC 29425, USA.
| | - Bärbel Rohrer
- Department of Ophthalmology, Medical University of South Carolina, Charleston, SC 29425, USA; Ralph H. Johnson VA Medical Center, Charleston, SC 29401, USA; Department of Neurosciences, Medical University of South Carolina, Charleston, SC, 29425, USA.
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18
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Wang C, Yang K, Liu X, Wang S, Song M, Belmonte JCI, Qu J, Liu GH, Zhang W. MAVS Antagonizes Human Stem Cell Senescence as a Mitochondrial Stabilizer. RESEARCH (WASHINGTON, D.C.) 2023; 6:0192. [PMID: 37521327 PMCID: PMC10374246 DOI: 10.34133/research.0192] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Accepted: 06/20/2023] [Indexed: 08/01/2023]
Abstract
Mitochondrial dysfunction is a hallmark feature of cellular senescence and organ aging. Here, we asked whether the mitochondrial antiviral signaling protein (MAVS), which is essential for driving antiviral response, also regulates human stem cell senescence. To answer this question, we used CRISPR/Cas9-mediated gene editing and directed differentiation techniques to generate various MAVS-knockout human stem cell models. We found that human mesenchymal stem cells (hMSCs) were sensitive to MAVS deficiency, as manifested by accelerated senescence phenotypes. We uncovered that the role of MAVS in maintaining mitochondrial structural integrity and functional homeostasis depends on its interaction with the guanosine triphosphatase optic atrophy type 1 (OPA1). Depletion of MAVS or OPA1 led to the dysfunction of mitochondria and cellular senescence, whereas replenishment of MAVS or OPA1 in MAVS-knockout hMSCs alleviated mitochondrial defects and premature senescence phenotypes. Taken together, our data underscore an uncanonical role of MAVS in safeguarding mitochondrial homeostasis and antagonizing human stem cell senescence.
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Affiliation(s)
- Cui Wang
- CAS Key Laboratory of Genomic and Precision Medicine, Beijing Institute of Genomics,
Chinese Academy of Sciences and China National Center for Bioinformation, Beijing 100101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Kuan Yang
- CAS Key Laboratory of Genomic and Precision Medicine, Beijing Institute of Genomics,
Chinese Academy of Sciences and China National Center for Bioinformation, Beijing 100101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
- Sino-Danish College,
University of Chinese Academy of Sciences, Beijing 101408, China
| | - Xiaoqian Liu
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology,
Chinese Academy of Sciences, Beijing 100101, China
- Institute for Stem Cell and Regeneration,
Chinese Academy of Sciences, Beijing 100101, China
- Beijing Institute for Stem Cell and Regenerative Medicine, Beijing 100101, China
| | - Si Wang
- Advanced Innovation Center for Human Brain Protection, National Clinical Research Center for Geriatric Disorders,
Xuanwu Hospital Capital Medical University, Beijing 100053, China
| | - Moshi Song
- University of Chinese Academy of Sciences, Beijing 100049, China
- Institute for Stem Cell and Regeneration,
Chinese Academy of Sciences, Beijing 100101, China
- Beijing Institute for Stem Cell and Regenerative Medicine, Beijing 100101, China
- State Key Laboratory of Membrane Biology, Institute of Zoology,
Chinese Academy of Sciences, Beijing 100101, China
| | | | - Jing Qu
- University of Chinese Academy of Sciences, Beijing 100049, China
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology,
Chinese Academy of Sciences, Beijing 100101, China
- Institute for Stem Cell and Regeneration,
Chinese Academy of Sciences, Beijing 100101, China
- Beijing Institute for Stem Cell and Regenerative Medicine, Beijing 100101, China
| | - Guang-Hui Liu
- University of Chinese Academy of Sciences, Beijing 100049, China
- Institute for Stem Cell and Regeneration,
Chinese Academy of Sciences, Beijing 100101, China
- Beijing Institute for Stem Cell and Regenerative Medicine, Beijing 100101, China
- Advanced Innovation Center for Human Brain Protection, National Clinical Research Center for Geriatric Disorders,
Xuanwu Hospital Capital Medical University, Beijing 100053, China
- State Key Laboratory of Membrane Biology, Institute of Zoology,
Chinese Academy of Sciences, Beijing 100101, China
| | - Weiqi Zhang
- CAS Key Laboratory of Genomic and Precision Medicine, Beijing Institute of Genomics,
Chinese Academy of Sciences and China National Center for Bioinformation, Beijing 100101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
- Sino-Danish College,
University of Chinese Academy of Sciences, Beijing 101408, China
- Institute for Stem Cell and Regeneration,
Chinese Academy of Sciences, Beijing 100101, China
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19
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Costa RD, Thomaz Neto FJ, Moustafa MT, Atilano SR, Chwa M, Cáceres-Del-Carpi J, Mohamed MH, Kenney MC, Kuppermann BD. The role of mitochondrial genes on nuclear gene expression in neovascular age related macular degeneration: analysis of nuclear VEGF gene expression after ranibizumab treatment in cytoplasmic hybrid retinal pigment epithelial cell lines correlated with clinical evolution. Int J Retina Vitreous 2023; 9:44. [PMID: 37491310 PMCID: PMC10367366 DOI: 10.1186/s40942-023-00476-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Accepted: 06/15/2023] [Indexed: 07/27/2023] Open
Abstract
PURPOSE The present study tests the hypothesis that mitochondrial genes have retrograde signaling capacity that influences the expression of nuclear genes related to angiogenesis pathways. Cytoplasmic hybrid (cybrid) in vitro cell lines with patient specific mitochondria inserted into an immortalized retinal pigment epithelial cell line (ARPE-19) were used to test this hypothesis. This type of analysis can provide important information to identify the optimal regimen of anti-VEGF treatment, personalizing age-related macular degeneration (AMD) therapies. METHODS Mitochondria deficient ARPE-19 cells (Rho0) were fused with AMD donor's platelets to create individual cybrid cell lines containing mitochondria from patients with phenotypic AMD disease and nuclear DNA from the immortalized RPE cell line. The cybrids were treated with Ranibizumab (Lucentis, Genentech, San Francisco, CA), at 4 different concentrations for 24 h, and subsequently the levels of reactive oxygen species (ROS), gene expression for VEGF-A, hypoxia-inducible factor 1-alpha (HIF1-a) and manganese superoxide dismutase (SOD2) were measured. The clinical evolution of the two AMD-donors were correlated with the molecular findings found in their 'personalized' cybrids. RESULTS Cybrids from Patient-01 showed down-regulation of gene expression of VEGF-A and HIF-1a at both 1X and 4X Ranibizumab concentrations. Patient-01 AMD cybrid cultures had an increase in the ROS levels at 1X (P = 0.0317), no changes at 2X (P = 0.8350) and a decrease at 4X (P = 0.0015) and 10X (P = 0.0011) of Ranibizumab. Clinically, Patient-01 responded to anti-VEGF therapy but eventually developed geographic atrophy. Patient-02 cybrids demonstrated up-regulation of gene expression of VEGF-A and HIF-1a at Ranibizumab 1X and 4X concentrations. There was decreased ROS levels with Ranibizumab 1X (P = 0.1606), 2X (P = 0.0388), 4X (P = 0.0010) and 10X (P = < 0.0001). Clinically, Patient-02 presented with a neovascular lesion associated with a prominent production of intraretinal fluid in clinical follow-up requiring regular and repeated intravitreal injections of Ranibizumab with recurrent subretinal fluid. CONCLUSIONS Our cybrid model has the potential to help personalize the treatment regimen with anti-VEGF drugs in patients with neovascular AMD. Further investigation is needed to better understand the role that the mitochondria play in the cellular response to anti-VEGF drugs. Future studies that focus on this model have the potential to help personalize anti-VEGF treatment.
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Affiliation(s)
- Rodrigo Donato Costa
- Gavin Herbert Eye Institute, University of California, 850 Health Sciences Road, Irvine, CA, 92697, USA
- Instituto Donato Oftalmologia, Poços de Caldas, Brazil
| | - Farid José Thomaz Neto
- Gavin Herbert Eye Institute, University of California, 850 Health Sciences Road, Irvine, CA, 92697, USA
| | - M Tarek Moustafa
- Gavin Herbert Eye Institute, University of California, 850 Health Sciences Road, Irvine, CA, 92697, USA
- Ophthalmology Department, Minia University, Minia, Egypt
| | - Shari R Atilano
- Gavin Herbert Eye Institute, University of California, 850 Health Sciences Road, Irvine, CA, 92697, USA
| | - Marilyn Chwa
- Gavin Herbert Eye Institute, University of California, 850 Health Sciences Road, Irvine, CA, 92697, USA
| | - Javier Cáceres-Del-Carpi
- Gavin Herbert Eye Institute, University of California, 850 Health Sciences Road, Irvine, CA, 92697, USA
- Facultad de Medicina Hipólito Unanue, Universidad Nacional Federico Villareal, Lima, Perú
| | - Mohamed Hamid Mohamed
- Gavin Herbert Eye Institute, University of California, 850 Health Sciences Road, Irvine, CA, 92697, USA
- Ophthalmology Department, Minia University, Minia, Egypt
| | - M Cristina Kenney
- Gavin Herbert Eye Institute, University of California, 850 Health Sciences Road, Irvine, CA, 92697, USA
| | - Baruch D Kuppermann
- Gavin Herbert Eye Institute, University of California, 850 Health Sciences Road, Irvine, CA, 92697, USA.
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Kaidonis G, Lamy R, Wu J, Yang D, Psaras C, Doan T, Stewart JM. Aqueous Fluid Transcriptome Profiling Differentiates Between Non-Neovascular and Neovascular AMD. Invest Ophthalmol Vis Sci 2023; 64:26. [PMID: 37471072 PMCID: PMC10365141 DOI: 10.1167/iovs.64.10.26] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/21/2023] Open
Abstract
Purpose Early and intermediate non-neovascular AMD (NN-AMD) has the potential to progress to either advanced NN-AMD with geographic atrophy, or to neovascular AMD (N-AMD) with CNV. This exploratory study performed an unbiased analysis of aqueous humor transcriptome in patients with early or intermediate NN-AMD vs. treatment-naïve N-AMD to determine the feasibility of using this method in future studies investigating pathways and triggers for conversion from one form to another. Methods Aqueous humor samples were obtained from 20 patients with early or intermediate NN-AMD and 20 patients with untreated N-AMD, graded on clinical examination and optical coherence tomography. Transcriptome profiles were generated using next-generation sequencing methods optimized for ocular samples. Top-ranked transcripts were compared between groups, and pathway enrichment analysis was performed. Results Seventy-eight differentially expressed transcripts were identified. Unsupervised clustering of differentially expressed transcripts was able to successfully differentiate between the two groups based on aqueous transcriptome alone. Pathway analysis highlighted changes in expression of genes associated with mitochondrial respiration, oxidative stress, ubiquitination, and neurogenesis between the two groups. Conclusions This pilot study compared the aqueous fluid transcriptome of patients with early or intermediate NN-AMD and untreated N-AMD. Differences in transcripts and transcriptome pathways identified in the aqueous of patients with early or intermediate NN-AMD compared with patients with N-AMD are consistent with those previously implicated in the pathogenesis of these distinct AMD subtypes. The findings from this exploratory study warrant further investigation using a larger, prospective study design, with the inclusion of a control group of eyes without AMD.
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Affiliation(s)
- Georgia Kaidonis
- Department of Ophthalmology, University of California, San Francisco, San Francisco, California, United States
| | - Ricardo Lamy
- Department of Ophthalmology, University of California, San Francisco, San Francisco, California, United States
- Department of Ophthalmology, Zuckerberg San Francisco General Hospital and Trauma Center, San Francisco, California, United States
| | - Joshua Wu
- Department of Ophthalmology, University of California, San Francisco, San Francisco, California, United States
- Department of Ophthalmology, Zuckerberg San Francisco General Hospital and Trauma Center, San Francisco, California, United States
| | - Daphne Yang
- Department of Ophthalmology, University of California, San Francisco, San Francisco, California, United States
- Department of Ophthalmology, Zuckerberg San Francisco General Hospital and Trauma Center, San Francisco, California, United States
| | - Catherine Psaras
- Department of Ophthalmology, University of California, San Francisco, San Francisco, California, United States
- Department of Ophthalmology, Zuckerberg San Francisco General Hospital and Trauma Center, San Francisco, California, United States
| | - Thuy Doan
- Department of Ophthalmology, University of California, San Francisco, San Francisco, California, United States
- Francis I. Proctor Foundation, San Francisco, California, United States
| | - Jay M Stewart
- Department of Ophthalmology, University of California, San Francisco, San Francisco, California, United States
- Department of Ophthalmology, Zuckerberg San Francisco General Hospital and Trauma Center, San Francisco, California, United States
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21
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Si Z, Zheng Y, Zhao J. The Role of Retinal Pigment Epithelial Cells in Age-Related Macular Degeneration: Phagocytosis and Autophagy. Biomolecules 2023; 13:901. [PMID: 37371481 DOI: 10.3390/biom13060901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 05/11/2023] [Accepted: 05/22/2023] [Indexed: 06/29/2023] Open
Abstract
Age-related macular degeneration (AMD) causes vision loss in the elderly population. Dry AMD leads to the formation of Drusen, while wet AMD is characterized by cell proliferation and choroidal angiogenesis. The retinal pigment epithelium (RPE) plays a key role in AMD pathogenesis. In particular, helioreceptor renewal depends on outer segment phagocytosis of RPE cells, while RPE autophagy can protect cells from oxidative stress damage. However, when the oxidative stress burden is too high and homeostasis is disturbed, the phagocytosis and autophagy functions of RPE become damaged, leading to AMD development and progression. Hence, characterizing the roles of RPE cell phagocytosis and autophagy in the pathogenesis of AMD can inform the development of potential therapeutic targets to prevent irreversible RPE and photoreceptor cell death, thus protecting against AMD.
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Affiliation(s)
- Zhibo Si
- Department of Ophthalmology, The Second Hospital of Jilin University, Changchun 130000, China
| | - Yajuan Zheng
- Department of Ophthalmology, The Second Hospital of Jilin University, Changchun 130000, China
| | - Jing Zhao
- Department of Ophthalmology, The Second Hospital of Jilin University, Changchun 130000, China
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22
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Piri N, Kaplan HJ. Role of Complement in the Onset of Age-Related Macular Degeneration. Biomolecules 2023; 13:biom13050832. [PMID: 37238702 DOI: 10.3390/biom13050832] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2023] [Revised: 05/09/2023] [Accepted: 05/11/2023] [Indexed: 05/28/2023] Open
Abstract
Age-related macular degeneration (AMD) is a progressive degenerative disease of the central retina and the leading cause of severe loss of central vision in people over age 50. Patients gradually lose central visual acuity, compromising their ability to read, write, drive, and recognize faces, all of which greatly impact daily life activities. Quality of life is significantly affected in these patients, and there are worse levels of depression as a result. AMD is a complex, multifactorial disease in which age and genetics, as well as environmental factors, all play a role in its development and progression. The mechanism by which these risk factors interact and converge towards AMD are not fully understood, and therefore, drug discovery is challenging, with no successful therapeutic attempt to prevent the development of this disease. In this review, we describe the pathophysiology of AMD and review the role of complement, which is a major risk factor in the development of AMD.
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Affiliation(s)
- Niloofar Piri
- Department of Ophthalmology, School of Medicine, Saint Louis University, St. Louis, MO 63104, USA
| | - Henry J Kaplan
- Departments of Ophthalmology and Biochemistry & Molecular Biology, School of Medicine, Saint Louis University, St. Louis, MO 63104, USA
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23
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Dhingra A, Tobias JW, Philp NJ, Boesze-Battaglia K. Transcriptomic Changes Predict Metabolic Alterations in LC3 Associated Phagocytosis in Aged Mice. Int J Mol Sci 2023; 24:6716. [PMID: 37047689 PMCID: PMC10095460 DOI: 10.3390/ijms24076716] [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: 02/24/2023] [Revised: 03/28/2023] [Accepted: 03/28/2023] [Indexed: 04/14/2023] Open
Abstract
LC3b (Map1lc3b) plays an essential role in canonical autophagy and is one of several components of the autophagy machinery that mediates non-canonical autophagic functions. Phagosomes are often associated with lipidated LC3b to promote phagosome maturation in a process called LC3-associated phagocytosis (LAP). Specialized phagocytes, such as mammary epithelial cells, retinal pigment epithelial (RPE) cells, and sertoli cells, utilize LAP for optimal degradation of phagocytosed material, including debris. In the visual system, LAP is critical to maintain retinal function, lipid homeostasis, and neuroprotection. In a mouse model of retinal lipid steatosis-mice lacking LC3b (LC3b-/-), we observed increased lipid deposition, metabolic dysregulation, and enhanced inflammation. Herein, we present a non-biased approach to determine if loss of LAP mediated processes modulate the expression of various genes related to metabolic homeostasis, lipid handling, and inflammation. A comparison of the RPE transcriptome of WT and LC3b-/- mice revealed 1533 DEGs, with ~73% upregulated and 27% downregulated. Enriched gene ontology (GO) terms included inflammatory response (upregulated DEGs), fatty acid metabolism, and vascular transport (downregulated DEGs). Gene set enrichment analysis (GSEA) identified 34 pathways; 28 were upregulated (dominated by inflammation/related pathways) and 6 were downregulated (dominated by metabolic pathways). Analysis of additional gene families identified significant differences for genes in the solute carrier family, RPE signature genes, and genes with a potential role in age-related macular degeneration. These data indicate that loss of LC3b induces robust changes in the RPE transcriptome contributing to lipid dysregulation and metabolic imbalance, RPE atrophy, inflammation, and disease pathophysiology.
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Affiliation(s)
- Anuradha Dhingra
- Department of Basic and Translational Sciences, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - John W. Tobias
- Penn Genomics and Sequencing Core, Department of Genetics, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Nancy J. Philp
- Department of Pathology, Anatomy, and Cell Biology, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Kathleen Boesze-Battaglia
- Department of Basic and Translational Sciences, University of Pennsylvania, Philadelphia, PA 19104, USA
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24
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Piskova T, Kozyrina AN, Di Russo J. Mechanobiological implications of age-related remodelling in the outer retina. BIOMATERIALS ADVANCES 2023; 147:213343. [PMID: 36801797 DOI: 10.1016/j.bioadv.2023.213343] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Revised: 02/01/2023] [Accepted: 02/10/2023] [Indexed: 02/17/2023]
Abstract
The outer retina consists of the light-sensitive photoreceptors, the pigmented epithelium, and the choroid, which interact in a complex manner to sustain homeostasis. The organisation and function of these cellular layers are mediated by the extracellular matrix compartment named Bruch's membrane, situated between the retinal epithelium and the choroid. Like many tissues, the retina experiences age-related structural and metabolic changes, which are relevant for understanding major blinding diseases of the elderly, such as age-related macular degeneration. Compared with other tissues, the retina mainly comprises postmitotic cells, making it less able to maintain its mechanical homeostasis over the years functionally. Aspects of retinal ageing, like the structural and morphometric changes of the pigment epithelium and the heterogenous remodelling of the Bruch's membrane, imply changes in tissue mechanics and may affect functional integrity. In recent years, findings in the field of mechanobiology and bioengineering highlighted the importance of mechanical changes in tissues for understanding physiological and pathological processes. Here, we review the current knowledge of age-related changes in the outer retina from a mechanobiological perspective, aiming to generate food for thought for future mechanobiology studies in the outer retina.
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Affiliation(s)
- Teodora Piskova
- Interdisciplinary Centre for Clinical Research, RWTH Aachen University, Pauwelstrasse 30, 52074 Aachen, Germany; Institute of Molecular and Cellular Anatomy, RWTH Aachen University, Wendlingweg 2, 52074 Aachen, Germany
| | - Aleksandra N Kozyrina
- Interdisciplinary Centre for Clinical Research, RWTH Aachen University, Pauwelstrasse 30, 52074 Aachen, Germany; Institute of Molecular and Cellular Anatomy, RWTH Aachen University, Wendlingweg 2, 52074 Aachen, Germany
| | - Jacopo Di Russo
- Interdisciplinary Centre for Clinical Research, RWTH Aachen University, Pauwelstrasse 30, 52074 Aachen, Germany; Institute of Molecular and Cellular Anatomy, RWTH Aachen University, Wendlingweg 2, 52074 Aachen, Germany; DWI - Leibniz-Institute for Interactive Materials, Forckenbeckstrasse 50, 52074 Aachen, Germany.
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25
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Dhingra A, Tobias JW, Philp NJ, Boesze-Battaglia K. Transcriptomic changes predict metabolic alterations in LC3 associated phagocytosis in aged mice. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.14.532586. [PMID: 36993501 PMCID: PMC10054970 DOI: 10.1101/2023.03.14.532586] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/21/2023]
Abstract
LC3b ( Map1lc3b ) plays an essential role in canonical autophagy and is one of several components of the autophagy machinery that mediates non-canonical autophagic functions. Phagosomes are often associated with lipidated LC3b, to pro-mote phagosome maturation in a process called LC3-associated phagocytosis (LAP). Specialized phagocytes such as mammary epithelial cells, retinal pigment epithelial (RPE) cells, and sertoli cells utilize LAP for optimal degradation of phagocytosed material, including debris. In the visual system, LAP is critical to maintain retinal function, lipid homeostasis and neuroprotection. In a mouse model of retinal lipid steatosis - mice lacking LC3b ( LC3b -/- ), we observed increased lipid deposition, metabolic dysregulation and enhanced inflammation. Herein we present a non-biased approach to determine if loss of LAP mediated processes modulate the expression of various genes related to metabolic homeostasis, lipid handling, and inflammation. A comparison of the RPE transcriptome of WT and LC3b -/- mice revealed 1533 DEGs, with ~73% upregulated and 27% down-regulated. Enriched gene ontology (GO) terms included inflammatory response (upregulated DEGs), fatty acid metabolism and vascular transport (downregulated DEGs). Gene set enrichment analysis (GSEA) identified 34 pathways; 28 were upregulated (dominated by inflammation/related pathways) and 6 were downregulated (dominated by metabolic pathways). Analysis of additional gene families identified significant differences for genes in the solute carrier family, RPE signature genes, and genes with potential role in age-related macular degeneration. These data indicate that loss of LC3b induces robust changes in the RPE transcriptome contributing to lipid dysregulation and metabolic imbalance, RPE atrophy, inflammation, and disease pathophysiology.
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26
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Ahsanuddin S, Rios HA, Otero-Marquez O, Macanian J, Zhou D, Rich C, Rosen RB. Flavoprotein fluorescence elevation is a marker of mitochondrial oxidative stress in patients with retinal disease. FRONTIERS IN OPHTHALMOLOGY 2023; 3:1110501. [PMID: 38983095 PMCID: PMC11182218 DOI: 10.3389/fopht.2023.1110501] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Accepted: 01/27/2023] [Indexed: 07/11/2024]
Abstract
Purpose Recent studies of glaucoma, age-related macular degeneration, and diabetic retinopathy have demonstrated that flavoprotein fluorescence (FPF) can be utilized non-invasively as an indicator of mitochondrial oxidative stress in the retina. However, a comprehensive assessment of the validity and reliability of FPF in differentiating between healthy and diseased eyes across multiple disease states is lacking. Here, we evaluate the sensitivity and specificity of FPF in discriminating between healthy and diseased eyes in four leading causes of visual impairment worldwide, one of which has not been previously evaluated using FPF. We also evaluate the association between FPF and visual acuity. Methods A total of 88 eyes [21 eyes of 21 unaffected controls, 20 eyes from 20 retinal vein occlusion (RVO) patients, 20 eyes from 20 diabetic retinopathy (DR) patients, 17 eyes from 17 chronic exudative age-related macular degeneration (exudative AMD) patients, and 10 eyes from 10 central serous retinopathy (CSR) patients] were included in the present cross-sectional observational study. Eyes were imaged non-invasively using a specially configured fundus camera OcuMet Beacon® (OcuSciences, Ann Arbor, MI). The macula was illuminated using a narrow bandwidth blue light (455 - 470 nm) and fluorescence was recorded using a narrow notch filter to match the peak emission of flavoproteins from 520 to 540 nm. AUROC analysis was used to determine the sensitivity of FPF in discriminating between diseased eyes and healthy eyes. Nonparametric Kruskal-Wallis Tests with post-hoc Mann Whitney U tests with the Holm-Bonferroni correction were performed to assess differences in FPF intensity, FPF heterogeneity, and best corrected visual acuity (BCVA) between the five groups. Spearman rank correlation coefficients were calculated to assess the relationship between FPF and BCVA. Results AUROC analysis indicated that FPF intensity is highly sensitive for detecting disease, particularly for exudative AMD subjects (0.989; 95% CI = 0.963 - 1.000, p=3.0 x 107). A significant difference was detected between the FPF intensity, FPF heterogeneity, and BCVA in all four disease states compared to unaffected controls (Kruskal-Wallis Tests, p = 1.06 x 10-8, p = 0.002, p = 5.54 x 10-8, respectively). Compared to healthy controls, FPF intensity values were significantly higher in RVO, DR, exudative AMD, and CSR (p < 0.001, p < 0.001, p < 0.001, and p = 0.001, respectively). Spearman rank correlation coefficient between FPF intensity and BCVA was ρ = 0.595 (p = 9.62 x 10-10). Conclusions Despite variations in structural retinal findings, FPF was found to be highly sensitive for detecting retinal disease. Significant FPF elevation were seen in all four disease states, with the exudative AMD patients exhibiting the highest FPF values compared to DR, CSR, and RVO subjects. This is consistent with the hypothesis that there is elevated oxidative stress in all of these conditions as previously demonstrated by blood studies. FPF intensity is moderately correlated with the late-in disease-marker BCVA, which suggests that the degree of FPF elevation can be used as a metabolic indicator of disease severity.
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Affiliation(s)
- Sofia Ahsanuddin
- Department of Ophthalmology, New York Eye and Ear Infirmary of Mount Sinai, New York, NY, United States
- Department of Ophthalmology, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Hernan A. Rios
- Department of Ophthalmology, New York Eye and Ear Infirmary of Mount Sinai, New York, NY, United States
- Department of Ophthalmology, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Oscar Otero-Marquez
- Department of Ophthalmology, New York Eye and Ear Infirmary of Mount Sinai, New York, NY, United States
- Department of Ophthalmology, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Jason Macanian
- Department of Medical Education, New York Medical College, Valhalla, NY, United States
| | - Davis Zhou
- Department of Ophthalmology, New York Eye and Ear Infirmary of Mount Sinai, New York, NY, United States
- Department of Ophthalmology, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Collin Rich
- OcuSciences Inc., Ann Arbor, MI, United States
| | - Richard B. Rosen
- Department of Ophthalmology, New York Eye and Ear Infirmary of Mount Sinai, New York, NY, United States
- Department of Ophthalmology, Icahn School of Medicine at Mount Sinai, New York, NY, United States
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Millington-Ward S, Chadderton N, Finnegan LK, Post IJM, Carrigan M, Nixon R, Humphries MM, Humphries P, Kenna PF, Palfi A, Farrar GJ. RPE-Directed Gene Therapy Improves Mitochondrial Function in Murine Dry AMD Models. Int J Mol Sci 2023; 24:ijms24043847. [PMID: 36835257 PMCID: PMC9968062 DOI: 10.3390/ijms24043847] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 02/03/2023] [Accepted: 02/04/2023] [Indexed: 02/17/2023] Open
Abstract
Age-related macular degeneration (AMD) is the most common cause of blindness in the aged population. However, to date there is no effective treatment for the dry form of the disease, representing 85-90% of cases. AMD is an immensely complex disease which affects, amongst others, both retinal pigment epithelium (RPE) and photoreceptor cells and leads to the progressive loss of central vision. Mitochondrial dysfunction in both RPE and photoreceptor cells is emerging as a key player in the disease. There are indications that during disease progression, the RPE is first impaired and RPE dysfunction in turn leads to subsequent photoreceptor cell degeneration; however, the exact sequence of events has not as yet been fully determined. We recently showed that AAV delivery of an optimised NADH-ubiquinone oxidoreductase (NDI1) gene, a nuclear-encoded complex 1 equivalent from S. cerevisiae, expressed from a general promoter, provided robust benefit in a variety of murine and cellular models of dry AMD; this was the first study employing a gene therapy to directly boost mitochondrial function, providing functional benefit in vivo. However, use of a restricted RPE-specific promoter to drive expression of the gene therapy enables exploration of the optimal target retinal cell type for dry AMD therapies. Furthermore, such restricted transgene expression could reduce potential off-target effects, possibly improving the safety profile of the therapy. Therefore, in the current study, we interrogate whether expression of the gene therapy from the RPE-specific promoter, Vitelliform macular dystrophy 2 (VMD2), might be sufficient to rescue dry AMD models.
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Affiliation(s)
- Sophia Millington-Ward
- The School of Genetics and Microbiology, Smurfit Institute of Genetics, Trinity College Dublin, D02 VF25 Dublin, Ireland
- Correspondence:
| | - Naomi Chadderton
- The School of Genetics and Microbiology, Smurfit Institute of Genetics, Trinity College Dublin, D02 VF25 Dublin, Ireland
| | - Laura K. Finnegan
- The School of Genetics and Microbiology, Smurfit Institute of Genetics, Trinity College Dublin, D02 VF25 Dublin, Ireland
| | - Iris J. M. Post
- The School of Genetics and Microbiology, Smurfit Institute of Genetics, Trinity College Dublin, D02 VF25 Dublin, Ireland
| | - Matthew Carrigan
- The School of Genetics and Microbiology, Smurfit Institute of Genetics, Trinity College Dublin, D02 VF25 Dublin, Ireland
| | - Rachel Nixon
- The School of Genetics and Microbiology, Smurfit Institute of Genetics, Trinity College Dublin, D02 VF25 Dublin, Ireland
| | - Marian M. Humphries
- The School of Genetics and Microbiology, Smurfit Institute of Genetics, Trinity College Dublin, D02 VF25 Dublin, Ireland
| | - Pete Humphries
- The School of Genetics and Microbiology, Smurfit Institute of Genetics, Trinity College Dublin, D02 VF25 Dublin, Ireland
| | - Paul F. Kenna
- The School of Genetics and Microbiology, Smurfit Institute of Genetics, Trinity College Dublin, D02 VF25 Dublin, Ireland
- The Research Foundation, Royal Victoria Eye and Ear Hospital, D02 XK51 Dublin, Ireland
| | - Arpad Palfi
- The School of Genetics and Microbiology, Smurfit Institute of Genetics, Trinity College Dublin, D02 VF25 Dublin, Ireland
| | - G. Jane Farrar
- The School of Genetics and Microbiology, Smurfit Institute of Genetics, Trinity College Dublin, D02 VF25 Dublin, Ireland
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The Anti-Aging Hormone Klotho Promotes Retinal Pigment Epithelium Cell Viability and Metabolism by Activating the AMPK/PGC-1α Pathway. Antioxidants (Basel) 2023; 12:antiox12020385. [PMID: 36829944 PMCID: PMC9952846 DOI: 10.3390/antiox12020385] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 01/30/2023] [Accepted: 01/30/2023] [Indexed: 02/08/2023] Open
Abstract
Initially discovered by Makuto Kuro-o in 1997, Klotho is a putative aging-suppressor gene when overexpressed and accelerates aging when deleted in mice. Previously, we showed that α-Klotho regulates retinal pigment epithelium (RPE) functions and protects against oxidative stress. However, the mechanisms by which Klotho influences RPE and retinal homeostasis remain elusive. Here, by performing a series of in vitro and in vivo experiments, we demonstrate that Klotho regulates cell viability under oxidative stress, mitochondrial gene expression and activity by inducing the phosphorylation of AMPK and p38MAPK, which in turn phosphorylate and activate CREB and ATF2, respectively, triggering PGC-1α transcription. The inhibition of Klotho in human RPE cells using CRISPR-Cas9 gene editing confirmed that a lack of Klotho negatively affects RPE functions, including mitochondrial activity and cell viability. Proteomic analyses showed that myelin sheath and mitochondrial-related proteins are downregulated in the RPE/retina of Kl-/- compared to WT mice, further supporting our biochemical observations. We conclude that Klotho acts upstream of the AMPK/PGC-1α pathway and regulates RPE/retinal resistance to oxidative stress, mitochondrial function, and gene and protein expressions. Thus, KL decline during aging could negatively impact retinal health, inducing age-related retinal degeneration.
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Retinal Pigment Epithelium Cell Development: Extrapolating Basic Biology to Stem Cell Research. Biomedicines 2023; 11:biomedicines11020310. [PMID: 36830851 PMCID: PMC9952929 DOI: 10.3390/biomedicines11020310] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2022] [Revised: 01/13/2023] [Accepted: 01/17/2023] [Indexed: 01/24/2023] Open
Abstract
The retinal pigment epithelium (RPE) forms an important cellular monolayer, which contributes to the normal physiology of the eye. Damage to the RPE leads to the development of degenerative diseases, such as age-related macular degeneration (AMD). Apart from acting as a physical barrier between the retina and choroidal blood vessels, the RPE is crucial in maintaining photoreceptor (PR) and visual functions. Current clinical intervention to treat early stages of AMD includes stem cell-derived RPE transplantation, which is still in its early stages of evolution. Therefore, it becomes essential to derive RPEs which are functional and exhibit features as observed in native human RPE cells. The conventional strategy is to use the knowledge obtained from developmental studies using various animal models and stem cell-based exploratory studies to understand RPE biogenies and developmental trajectory. This article emphasises such studies and aims to present a comprehensive understanding of the basic biology, including the genetics and molecular pathways of RPE development. It encompasses basic developmental biology and stem cell-based developmental studies to uncover RPE differentiation. Knowledge of the in utero developmental cues provides an inclusive methodology required for deriving RPEs using stem cells.
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Muste JC, Russell MW, Chen AX, Seth K, Iyer AI, Valentim CCS, Wu AK, Kuo BL, Kalur A, Sastry R, Hom GL, Conti TF, Rich CA, Talcott KE, Sharma S, Singh RP. Functional Imaging of Mitochondria in Age-Related Macular Degeneration Using Flavoprotein Fluorescence. Ophthalmic Surg Lasers Imaging Retina 2023; 54:24-31. [PMID: 36626211 DOI: 10.3928/23258160-20221214-03] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
PURPOSE Oxidative stress-induced mitochondrial dysfunction is implicated in the pathogenesis of age-related macular degeneration (AMD). Oxidized mitochondrial flavoprotein fluorescence (FPF) may serve as a quantifiable biomarker of oxidative stress, reported as either mean score for the entire image (intensity) or variability (heterogeneity). This study examines FPF intensity and heterogeneity across a large patient cohort of various Beckman stages of AMD. METHODS This study enrolled patients with isolated AMD and healthy control patients with no retinopathy between 2018 and 2021. Multivariate logistic regression analysis included stage of AMD, age, gender, ethnicity, and smoking status. Analysis of Variance test compared mean FPF intensity and heterogeneity between disease states. RESULTS Four hundred fifty-six eyes (228 AMD eyes, 228 age-matched control eyes) were included in the final multivariate analysis. Intermediate, geographic atrophy (GA), and neovascular AMD correlated with significantly increased FPF intensity (P < 0.001, respectively), while all AMD stages correlated with increased FPF heterogeneity (P < 0.001, respectively). FPF intensity and heterogeneity were significant negative predictors of visual acuity (P = 0.018 and 0.024, respectively). CONCLUSIONS This prospective observational study further implicates mitochondrial damage in AMD pathophysiology. Long-term clinical trials will be needed to examine the predictive role of FPF imaging in patients over time. [Ophthalmic Surg Lasers Imaging Retina 2023;54:24-31.].
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Fisher CR, Shaaeli AA, Ebeling MC, Montezuma SR, Ferrington DA. Investigating mitochondrial fission, fusion, and autophagy in retinal pigment epithelium from donors with age-related macular degeneration. Sci Rep 2022; 12:21725. [PMID: 36526679 PMCID: PMC9758189 DOI: 10.1038/s41598-022-26012-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2022] [Accepted: 12/02/2022] [Indexed: 12/23/2022] Open
Abstract
Age-related macular degeneration (AMD) is the leading cause of irreversible blindness in developed countries, characterized by the death of retinal pigment epithelial (RPE) cells and photoreceptors. Previous studies report an accumulation of damaged and dysfunctional mitochondria in RPE of human donors with AMD. Understanding how damaged mitochondria accumulate in AMD is an important step in discovering disease mechanisms and identifying therapeutic targets. In this report, we assessed mitochondrial fission and fusion by quantifying proteins and measured mitochondrial autophagy (mitophagy) via protein analysis and advanced imaging techniques using mitochondrial targeted mKeima in primary human RPE from donors with or without AMD. We report disease-specific differences in mitochondrial proteins that regulate fission, fusion, and mitophagy that were present at baseline and with treatments to stimulate these pathways. Data suggest AMD RPE utilize receptor-mediated mitophagy as a compensatory mechanism for deficits in the ubiquitin-mediated mitophagy pathway. These changes in mitochondrial homeostasis could lead to the buildup of damaged and dysfunctional mitochondria observed in the RPE of AMD donors.
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Affiliation(s)
- Cody R. Fisher
- grid.17635.360000000419368657Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, MN 55455 USA ,grid.17635.360000000419368657Graduate Program in Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455 USA
| | - Adam A. Shaaeli
- grid.17635.360000000419368657Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, MN 55455 USA ,grid.17635.360000000419368657Undergraduate program in Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455 USA
| | - Mara C. Ebeling
- grid.17635.360000000419368657Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, MN 55455 USA
| | - Sandra R. Montezuma
- grid.17635.360000000419368657Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, MN 55455 USA
| | - Deborah A. Ferrington
- grid.17635.360000000419368657Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, MN 55455 USA ,grid.17635.360000000419368657Graduate Program in Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455 USA ,grid.17635.360000000419368657Stem Cell Institute, University of Minnesota, Minneapolis, MN 55455 USA ,grid.280881.b0000 0001 0097 5623Doheny Eye Institute, Pasadena, CA 91103 USA
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Malek G, Campisi J, Kitazawa K, Webster C, Lakkaraju A, Skowronska-Krawczyk D. Does senescence play a role in age-related macular degeneration? Exp Eye Res 2022; 225:109254. [PMID: 36150544 PMCID: PMC10032649 DOI: 10.1016/j.exer.2022.109254] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2021] [Revised: 09/07/2022] [Accepted: 09/14/2022] [Indexed: 12/29/2022]
Abstract
Advanced age is the most established risk factor for developing age-related macular degeneration (AMD), one of the leading causes of visual impairment in the elderly, in Western and developed countries. Similarly, after middle age, there is an exponential increase in pathologic molecular and cellular events that can induce senescence, traditionally defined as an irreversible loss of the cells' ability to divide and most recently reported to also occur in select post-mitotic and terminally differentiated cells, such as neurons. Together these facts raise the question as to whether or not cellular senescence, may play a role in the development of AMD. A number of studies have reported the effect of ocular-relevant inducers of senescence using primarily in vitro models of poorly polarized, actively dividing retinal pigment epithelial (RPE) cell lines. However, in interpretating the data, the fidelity of these culture models to the RPE in vivo, must be considered. Fewer studies have explored the presence and/or impact of senescent cells in in vivo models that present with phenotypic features of AMD, leaving this an open field for further investigation. The goal of this review is to discuss current thoughts on the potential role of senescence in AMD development and progression, with consideration of the model systems used and their relevance to human disease.
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Affiliation(s)
- Goldis Malek
- Duke Eye Center, Department of Ophthalmology, Duke University School of Medicine, Durham, NC, USA; Department of Pathology, Duke University School of Medicine, Durham, NC, USA.
| | - Judith Campisi
- Buck Institute for Research on Aging, Novato, CA, USA; Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Koji Kitazawa
- Buck Institute for Research on Aging, Novato, CA, USA; Department of Ophthalmology, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Corey Webster
- Buck Institute for Research on Aging, Novato, CA, USA
| | - Aparna Lakkaraju
- Departments of Ophthalmology and Anatomy, School of Medicine, University of California, San Francisco, CA, USA
| | - Dorota Skowronska-Krawczyk
- Department of Physiology and Biophysics, Department of Ophthalmology, Center for Translational Vision Research, School of Medicine, University of California, Irvine, CA, USA
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Dissecting Regulators of Aging and Age-Related Macular Degeneration in the Retinal Pigment Epithelium. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2022; 2022:6009787. [PMID: 36439688 PMCID: PMC9683958 DOI: 10.1155/2022/6009787] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Accepted: 09/16/2022] [Indexed: 11/17/2022]
Abstract
Age-related macular degeneration (AMD), the leading cause of blindness in elderly populations, involves the loss of central vision due to progressive dysfunction of the retinal pigment epithelium (RPE) and subsequent loss of light-sensing photoreceptors. While age is a key risk factor, not every aged individual develops AMD. Thus, the critical question is what specific cellular changes tip the balance from healthy aging to disease. To distinguish between changes associated with aging and AMD, we compared the RPE proteome in human eye bank tissue from nondiseased donors during aging (n = 50, 29-91 years) and in donors with AMD (n = 36) compared to age-matched donors without disease (n = 28). Proteins from RPE cells were separated on two-dimensional gels, analyzed for content, and identified using mass spectrometry. A total of 58 proteins displayed significantly altered content with either aging or AMD. Proteins involved in metabolism, protein turnover, stress response, and cell death were altered with both aging and AMD. However, the direction of change was predominantly opposite. With aging, we detected an overall decrease in metabolism and reductions in stress-associated proteins, proteases, and chaperones. With AMD, we observed upregulation of metabolic proteins involved in glycolysis, TCA, and fatty acid metabolism, with a concurrent decline in oxidative phosphorylation, suggesting a reprogramming of energy utilization. Additionally, we detected upregulation of proteins involved in the stress response and protein turnover. Predicted upstream regulators also showed divergent results, with inhibition of inflammation and immune response with aging and activation of these processes with AMD. Our results support the idea that AMD is not simply advanced aging but rather the culmination of perturbed protein homeostasis, defective bioenergetics, and increased oxidative stress within the aging RPE, exacerbated by environmental factors and the genetic background of an individual.
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Burgoyne T, Toms M, Way C, Tracey-White D, Futter CE, Moosajee M. Changes in Mitochondrial Size and Morphology in the RPE and Photoreceptors of the Developing and Ageing Zebrafish. Cells 2022; 11:cells11223542. [PMID: 36428971 PMCID: PMC9688747 DOI: 10.3390/cells11223542] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Revised: 10/05/2022] [Accepted: 11/04/2022] [Indexed: 11/12/2022] Open
Abstract
Mitochondria are essential adenosine triphosphate (ATP)-generating cellular organelles. In the retina, they are highly numerous in the photoreceptors and retinal pigment epithelium (RPE) due to their high energetic requirements. Fission and fusion of the mitochondria within these cells allow them to adapt to changing demands over the lifespan of the organism. Using transmission electron microscopy, we examined the mitochondrial ultrastructure of zebrafish photoreceptors and RPE from 5 days post fertilisation (dpf) through to late adulthood (3 years). Notably, mitochondria in the youngest animals were large and irregular shaped with a loose cristae architecture, but by 8 dpf they had reduced in size and expanded in number with more defined cristae. Investigation of temporal gene expression of several mitochondrial-related markers indicated fission as the dominant mechanism contributing to the changes observed over time. This is likely to be due to continued mitochondrial stress resulting from the oxidative environment of the retina and prolonged light exposure. We have characterised retinal mitochondrial ageing in a key vertebrate model organism, that provides a basis for future studies of retinal diseases that are linked to mitochondrial dysfunction.
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Affiliation(s)
- Thomas Burgoyne
- UCL Institute of Ophthalmology, University College London, London EC1V 9EL, UK
- Royal Brompton Hospital, Guy’s and St Thomas’ NHS Foundation Trust, London SW3 6NP, UK
| | - Maria Toms
- UCL Institute of Ophthalmology, University College London, London EC1V 9EL, UK
- The Francis Crick Institute, London NW1 1AT, UK
| | - Chris Way
- UCL Institute of Ophthalmology, University College London, London EC1V 9EL, UK
| | - Dhani Tracey-White
- UCL Institute of Ophthalmology, University College London, London EC1V 9EL, UK
| | - Clare E. Futter
- UCL Institute of Ophthalmology, University College London, London EC1V 9EL, UK
| | - Mariya Moosajee
- UCL Institute of Ophthalmology, University College London, London EC1V 9EL, UK
- The Francis Crick Institute, London NW1 1AT, UK
- Department of Ophthalmology, Great Ormond Street Hospital for Children NHS Foundation Trust, London WC1N 3JH, UK
- Department of Genetics, Moorfields Eye Hospital NHS Foundation Trust, London EC1V 2PD, UK
- Correspondence:
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Zhuang X, Ma J, Xu G, Sun Z. SHP-1 knockdown suppresses mitochondrial biogenesis and aggravates mitochondria-dependent apoptosis induced by all trans retinal through the STING/AMPK pathways. Mol Med 2022; 28:125. [PMID: 36273174 PMCID: PMC9588232 DOI: 10.1186/s10020-022-00554-w] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2022] [Accepted: 10/06/2022] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND Oxidative stress-caused damage to the retinal pigment epithelium (RPE) underlies the onset and progression of age-related macular degeneration (AMD). Impaired mitochondrial biogenesis sensitizes RPE cells to mitochondrial dysfunction, energy insufficiency and death. Src-homology 2 domain-containing phosphatase (SHP)-1 is important in regulating immune responses and cell survival. However, its roles in cell survival are not always consistent. Until now, the effects of SHP-1 on RPE dysfunction, especially mitochondrial homeostasis, remain to be elucidated. We sought to clarify the effects of SHP-1 in RPE cells in response to atRAL-induced oxidative stress and determine the regulatory mechanisms involved. METHODS In the all trans retinal (atRAL)-induced oxidative stress model, we used the vector of lentivirus to knockdown the expression of SHP-1 in ARPE-19 cells. CCK-8 assay, Annexin V/PI staining and JC-1 staining were utilized to determine the cell viability, cell apoptosis and mitochondrial membrane potential. We also used immunoprecipitation to examine the ubiquitination modification of stimulator of interferon genes (STING) and its interaction with SHP-1. The expression levels of mitochondrial marker, proteins related to mitochondrial biogenesis, and signaling molecules involved were examined by western blotting analysis. RESULTS We found that SHP-1 knockdown predisposed RPE cells to apoptosis, aggravated mitochondrial damage, and repressed mitochondrial biogenesis after treatment with atRAL. Immunofluoresent staining and immunoprecipitation analysis confirmed that SHP-1 interacted with the endoplasmic reticulum-resident STING and suppressed K63-linked ubiquitination and activation of STING. Inhibition of STING with the specific antagonist H151 attenuated the effects of SHP-1 knockdown on mitochondrial biogenesis and oxidative damage. The adenosine monophosphate-activated protein kinase (AMPK) pathway acted as the crucial downstream target of STING and was involved in the regulatory processes. CONCLUSIONS These findings suggest that SHP-1 knockdown potentiates STING overactivation and represses mitochondrial biogenesis and cell survival, at least in part by blocking the AMPK pathway in RPE cells. Therefore, restoring mitochondrial health by regulating SHP-1 in RPE cells may be a potential therapeutic strategy for degenerative retinal diseases including AMD.
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Affiliation(s)
- Xiaonan Zhuang
- Department of Ophthalmology, Eye and ENT Hospital of Fudan University, 83 Fenyang Road, Shanghai, 200031, China
- Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai, China
- NHC Key Laboratory of Myopia, Fudan University, Shanghai, China
| | - Jun Ma
- Eye Institute, Eye & ENT Hospital, Fudan University, Shanghai, China
- Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai, China
- NHC Key Laboratory of Myopia, Fudan University, Shanghai, China
| | - Gezhi Xu
- Department of Ophthalmology, Eye and ENT Hospital of Fudan University, 83 Fenyang Road, Shanghai, 200031, China
- Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai, China
- NHC Key Laboratory of Myopia, Fudan University, Shanghai, China
| | - Zhongcui Sun
- Department of Ophthalmology, Eye and ENT Hospital of Fudan University, 83 Fenyang Road, Shanghai, 200031, China.
- Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai, China.
- NHC Key Laboratory of Myopia, Fudan University, Shanghai, China.
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Liu L, Li C, Yu H, Yang X. A critical review on air pollutant exposure and age-related macular degeneration. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 840:156717. [PMID: 35709989 DOI: 10.1016/j.scitotenv.2022.156717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2022] [Revised: 05/25/2022] [Accepted: 06/11/2022] [Indexed: 06/15/2023]
Abstract
Age-related macular degeneration (AMD) is the leading cause of visual impairments and blindness worldwide in the elderly and its incidence strongly increases with ages. The etiology of AMD is complex and attributed to the genetic modifiers, environmental factors and gene-environment interactions. Recently, the impacts of air pollution on the development of eye diseases have become the new area of focus, and disordered air exposure combined with inadequate health management has caused problems for the eye health, such as dry eye, glaucoma, and retinopathy, while its specific role in the occurrence of AMD is still not well understood. In order to summarize the progress of this research field, we performed a critical review to summarize the epidemiological and mechanism evidence on the association between air pollutants exposure and AMD. This review documented that exposure to air pollutants will accelerate or worsen the morbidity and prevalence of AMD. Air pollutants exposure may change the homeostasis, interfere with the inflammatory response, and take direct action on the lipid metabolism and oxidative stress in the macula. More attention should be given to understanding the impact of ambient air pollution on AMD worldwide.
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Affiliation(s)
- Lei Liu
- Guangdong Eye Institute, Department of Ophthalmology, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou 510080, China
| | - Cong Li
- Guangdong Eye Institute, Department of Ophthalmology, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou 510080, China; School of Medicine, South China University of Technology, Guangzhou 510006, China
| | - Honghua Yu
- Guangdong Eye Institute, Department of Ophthalmology, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou 510080, China
| | - Xiaohong Yang
- Guangdong Eye Institute, Department of Ophthalmology, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou 510080, China.
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Chen CT, Shao Z, Fu Z. Dysfunctional peroxisomal lipid metabolisms and their ocular manifestations. Front Cell Dev Biol 2022; 10:982564. [PMID: 36187472 PMCID: PMC9524157 DOI: 10.3389/fcell.2022.982564] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 08/17/2022] [Indexed: 11/13/2022] Open
Abstract
Retina is rich in lipids and dyslipidemia causes retinal dysfunction and eye diseases. In retina, lipids are not only important membrane component in cells and organelles but also fuel substrates for energy production. However, our current knowledge of lipid processing in the retina are very limited. Peroxisomes play a critical role in lipid homeostasis and genetic disorders with peroxisomal dysfunction have different types of ocular complications. In this review, we focus on the role of peroxisomes in lipid metabolism, including degradation and detoxification of very-long-chain fatty acids, branched-chain fatty acids, dicarboxylic acids, reactive oxygen/nitrogen species, glyoxylate, and amino acids, as well as biosynthesis of docosahexaenoic acid, plasmalogen and bile acids. We also discuss the potential contributions of peroxisomal pathways to eye health and summarize the reported cases of ocular symptoms in patients with peroxisomal disorders, corresponding to each disrupted peroxisomal pathway. We also review the cross-talk between peroxisomes and other organelles such as lysosomes, endoplasmic reticulum and mitochondria.
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Affiliation(s)
- Chuck T. Chen
- Department of Nutritional Sciences, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Zhuo Shao
- Post-Graduate Medical Education, University of Toronto, Toronto, ON, Canada
- Division of Clinical and Metabolic Genetics, the Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
- The Genetics Program, North York General Hospital, University of Toronto, Toronto, ON, Canada
| | - Zhongjie Fu
- Department of Ophthalmology, Boston Children’s Hospital, Harvard Medical School, Boston, MA, United States
- *Correspondence: Zhongjie Fu,
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Chang Q, Chen S, Yang T. The GPCR Antagonistic Drug CM-20 Stimulates Mitochondrial Activity in Human RPE Cells. Open Biochem J 2022; 16. [PMID: 36090845 PMCID: PMC9460984 DOI: 10.2174/1874091x-v16-e2206270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Background:
Mitochondrial dysfunction in retinal pigment epithelium (RPE) is a pathogenic factor in age-related macular degeneration (AMD). Improvement of mitochondrial function may ameliorate RPE bioenergetics status, which may in turn nourish the retinal photoreceptors against degenerative loss.
Objective:
The purpose of this study is to examine the G-protein coupled receptor (GPCR) antagonistic drug CM-20 in modulating mitochondrial function in RPE cells.
Methods:
Human-derived ARPE-19 cell line was differentiated to improve RPE morphology. Dose response of CM-20 was performed to examine mitochondrial membrane potential (MMP). Secondary validation with multiplexed live-cell mitochondrial imaging was performed. Protection of CM-20 to mitochondria against oxidative stress was detected under co-treatment with hydrogen peroxide.
Results:
Treatment with CM-20 elicited a dose-dependent increase of MMP. Multiplexed live-cell mitochondrial imaging showed consistent increase of MMP at an optimal concentration of CM-20 (12.5 µM). MMP was significantly reduced under hydrogen peroxide-induced oxidative stress and treatment with CM-20 showed rescue effects to MMP.
Conclusion:
CM-20 increases mitochondrial function and protects mitochondria under oxidative stress. As both GPCRs and mitochondria are potential drug targets, retinal neuroprotective testing of CM-20 is warranted in animal models of retinal degeneration.
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Fehér J, Élő Á, István L, Nagy ZZ, Radák Z, Scuderi G, Artico M, Kovács I. Microbiota mitochondria disorders as hubs for early age-related macular degeneration. GeroScience 2022; 44:2623-2653. [PMID: 35978068 PMCID: PMC9385247 DOI: 10.1007/s11357-022-00620-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Accepted: 07/01/2022] [Indexed: 01/07/2023] Open
Abstract
Age-related macular degeneration (AMD) is a progressive neurodegenerative disease affecting the central area (macula lutea) of the retina. Research on the pathogenic mechanism of AMD showed complex cellular contribution governed by such risk factors as aging, genetic predisposition, diet, and lifestyle. Recent studies suggested that microbiota is a transducer and a modifier of risk factors for neurodegenerative diseases, and mitochondria may be one of the intracellular targets of microbial signaling molecules. This review explores studies supporting a new concept on the contribution of microbiota-mitochondria disorders to AMD. We discuss metabolic, vascular, immune, and neuronal mechanism in AMD as well as key alterations of photoreceptor cells, retinal pigment epithelium (RPE), Bruch's membrane, choriocapillaris endothelial, immune, and neuronal cells. Special attention was paid to alterations of mitochondria contact sites (MCSs), an organelle network of mitochondria, endoplasmic reticulum, lipid droplets (LDs), and peroxisomes being documented based on our own electron microscopic findings from surgically removed human eyes. Morphometry of Bruch's membrane lipids and proteoglycans has also been performed in early AMD and aged controls. Microbial metabolites (short-chain fatty acids, polyphenols, and secondary bile acids) and microbial compounds (lipopolysaccharide, peptidoglycan, and bacterial DNA)-now called postbiotics-in addition to local effects on resident microbiota and mucous membrane, regulate systemic metabolic, vascular, immune, and neuronal mechanisms in normal conditions and in various common diseases. We also discuss their antioxidant, anti-inflammatory, and metabolic effects as well as experimental and clinical observations on regulating the main processes of photoreceptor renewal, mitophagy, and autophagy in early AMD. These findings support an emerging concept that microbiota-mitochondria disorders may be a crucial pathogenic mechanism of early AMD; and similarly, to other age-related neurodegenerative diseases, new treatment approaches should be targeted at these disorders.
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Affiliation(s)
- János Fehér
- PRIMAVERA Program, Nutripharma Hungaria Ltd., Budapest, Hungary
| | - Ágnes Élő
- grid.11804.3c0000 0001 0942 9821Department of Ophthalmology, Semmelweis University, Budapest, Hungary
| | - Lilla István
- grid.11804.3c0000 0001 0942 9821Department of Ophthalmology, Semmelweis University, Budapest, Hungary
| | - Zoltán Zsolt Nagy
- grid.11804.3c0000 0001 0942 9821Department of Ophthalmology, Semmelweis University, Budapest, Hungary
| | - Zsolt Radák
- grid.472475.70000 0000 9243 1481Research Institute of Sport Science, University of Physical Education, Budapest, Hungary
| | - Gianluca Scuderi
- grid.7841.aOphthalmology Unit, NESMOS Department, Sant’Andrea Hospital, Faculty of Medicine and Psychology, Sapienza University of Rome, Rome, Italy
| | - Marco Artico
- grid.417007.5Department of Sensory Organs, “Sapienza” University of Rome, Roma, Italy
| | - Illés Kovács
- grid.11804.3c0000 0001 0942 9821Department of Ophthalmology, Semmelweis University, Budapest, Hungary ,grid.5386.8000000041936877XDepartment of Ophthalmology, Weill Cornell Medical College, New York City, NY USA
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Tong Y, Zhang Z, Wang S. Role of Mitochondria in Retinal Pigment Epithelial Aging and Degeneration. FRONTIERS IN AGING 2022; 3:926627. [PMID: 35912040 PMCID: PMC9337215 DOI: 10.3389/fragi.2022.926627] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Accepted: 06/21/2022] [Indexed: 12/17/2022]
Abstract
Retinal pigment epithelial (RPE) cells form a monolayer between the neuroretina and choroid. It has multiple important functions, including acting as outer blood-retina barrier, maintaining the function of neuroretina and photoreceptors, participating in the visual cycle and regulating retinal immune response. Due to high oxidative stress environment, RPE cells are vulnerable to dysfunction, cellular senescence, and cell death, which underlies RPE aging and age-related diseases, including age-related macular degeneration (AMD). Mitochondria are the powerhouse of cells and a major source of cellular reactive oxygen species (ROS) that contribute to mitochondrial DNA damage, cell death, senescence, and age-related diseases. Mitochondria also undergo dynamic changes including fission/fusion, biogenesis and mitophagy for quality control in response to stresses. The role of mitochondria, especially mitochondrial dynamics, in RPE aging and age-related diseases, is still unclear. In this review, we summarize the current understanding of mitochondrial function, biogenesis and especially dynamics such as morphological changes and mitophagy in RPE aging and age-related RPE diseases, as well as in the biological processes of RPE cellular senescence and cell death. We also discuss the current preclinical and clinical research efforts to prevent or treat RPE degeneration by restoring mitochondrial function and dynamics.
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Affiliation(s)
- Yao Tong
- Department of Cell and Molecular Biology, Tulane University, New Orleans, LA, United States
| | - Zunyi Zhang
- Department of Cell and Molecular Biology, Tulane University, New Orleans, LA, United States
| | - Shusheng Wang
- Department of Cell and Molecular Biology, Tulane University, New Orleans, LA, United States
- Department of Ophthalmology, Tulane University, New Orleans, LA, United States
- Tulane Personalized Health Institute, Tulane University, New Orleans, LA, United States
- *Correspondence: Shusheng Wang,
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Sridevi Gurubaran I, Hytti M, Kaarniranta K, Kauppinen A. Epoxomicin, a Selective Proteasome Inhibitor, Activates AIM2 Inflammasome in Human Retinal Pigment Epithelium Cells. Antioxidants (Basel) 2022; 11:antiox11071288. [PMID: 35883779 PMCID: PMC9311580 DOI: 10.3390/antiox11071288] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 06/26/2022] [Accepted: 06/26/2022] [Indexed: 02/04/2023] Open
Abstract
Emerging evidence suggests that the intracellular clearance system plays a vital role in maintaining homeostasis and in regulating oxidative stress and inflammation in retinal pigment epithelium (RPE) cells. Dysfunctional proteasomes and autophagy in RPE cells have been associated with the pathogenesis of age-related macular degeneration. We have previously shown that the inhibition of proteasomes using MG-132 activates the NLR family pyrin domain containing 3 (NLRP3) inflammasome in human RPE cells. However, MG-132 is a non-selective proteasome inhibitor. In this study, we used the selective proteasome inhibitor epoxomicin to study the effect of non-functional intracellular clearance systems on inflammasome activation. Our data show that epoxomicin-induced proteasome inhibition promoted both nicotinamide adenine dinucleotide phosphate oxidase and mitochondria-mediated oxidative stress and release of mitochondrial DNA to the cytosol, which resulted in potassium efflux-dependent absence in melanoma 2 (AIM2) inflammasome activation and subsequent interleukin-1β secretion in ARPE-19 cells. The non-specific proteasome inhibitor MG-132 activated both NLRP3 and AIM2 inflammasomes and oxidative stress predominated as the activation mechanism, but modest potassium efflux was also detected. Collectively, our data suggest that a selective proteasome inhibitor is a potent inflammasome activator in human RPE cells and emphasize the role of the AIM2 inflammasome in addition to the more commonly known NLRP3 inflammasome.
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Affiliation(s)
- Iswariyaraja Sridevi Gurubaran
- Department of Ophthalmology, Institute of Clinical Medicine, University of Eastern Finland, 70210 Kuopio, Finland; (I.S.G.); (K.K.)
| | - Maria Hytti
- Immuno-Ophthalmology, School of Pharmacy, Faculty of Health Sciences, University of Eastern Finland, 70210 Kuopio, Finland;
| | - Kai Kaarniranta
- Department of Ophthalmology, Institute of Clinical Medicine, University of Eastern Finland, 70210 Kuopio, Finland; (I.S.G.); (K.K.)
- Department of Ophthalmology, University of Eastern Finland, 70211 Kuopio, Finland
- Department of Ophthalmology, Kuopio University Hospital, 70029 Kuopio, Finland
| | - Anu Kauppinen
- Department of Ophthalmology, Institute of Clinical Medicine, University of Eastern Finland, 70210 Kuopio, Finland; (I.S.G.); (K.K.)
- Immuno-Ophthalmology, School of Pharmacy, Faculty of Health Sciences, University of Eastern Finland, 70210 Kuopio, Finland;
- Correspondence:
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42
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Peng M, Zhou X, Yao F, Li H, Song W, Xiong S, Xia X. (–)-Epicatechin Provides Neuroprotection in Sodium Iodate-Induced Retinal Degeneration. Front Med (Lausanne) 2022; 9:879901. [PMID: 35833100 PMCID: PMC9271623 DOI: 10.3389/fmed.2022.879901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Accepted: 05/18/2022] [Indexed: 11/30/2022] Open
Abstract
Oxidative stress, mitochondrial impairment, and pathological amyloid beta (Aβ) deposition are involved in the pathogenesis of dry age-related macular degeneration (AMD). The natural flavonoid (–)-epicatechin (EC) is known to be an antioxidant and neuroprotective compound. Whether EC plays a therapeutic role in AMD is unknown. In this work, we aimed to assess the efficacy and molecular mechanisms of EC against sodium iodate (NaIO3)-induced retinal degeneration in C57BL/6 mice via bioinformatic, morphological, and functional methods. We demonstrated that EC had no toxic effects on the retina and could ameliorate retinal deformation and thinning. EC treatment prevented outer retinal degeneration, reduced drusen-like deposits, increased b-wave amplitude in electroretinography, blocked retinal gliosis, and increased the number and quality of mitochondria. Importantly, EC increased the protein expression of OPA1 and decreased the expression of PINK1, indicating the role of EC in mitochondrial fusion that impaired by NaIO3. Moreover, EC downregulated APP and TMEM97 levels, upregulated PGRMC1 levels, and reduced subretinal Aβ accumulation. This study illustrated that EC, which may become a promising therapeutic strategy for AMD, prevented NaIO3-induced retinal degeneration, and this improvement may be associated with the mitochondrial quality control and the TMEM97/PGRMC1/Aβ signaling pathway.
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Affiliation(s)
- Manjuan Peng
- Eye Center of Xiangya Hospital, Central South University, Changsha, China
- Hunan Key Laboratory of Ophthalmology, Xiangya Hospital, Central South University, Changsha, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Xuezhi Zhou
- Eye Center of Xiangya Hospital, Central South University, Changsha, China
- Hunan Key Laboratory of Ophthalmology, Xiangya Hospital, Central South University, Changsha, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Fei Yao
- Eye Center of Xiangya Hospital, Central South University, Changsha, China
- Hunan Key Laboratory of Ophthalmology, Xiangya Hospital, Central South University, Changsha, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Haibo Li
- Eye Center of Xiangya Hospital, Central South University, Changsha, China
- Hunan Key Laboratory of Ophthalmology, Xiangya Hospital, Central South University, Changsha, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Weitao Song
- Eye Center of Xiangya Hospital, Central South University, Changsha, China
- Hunan Key Laboratory of Ophthalmology, Xiangya Hospital, Central South University, Changsha, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Siqi Xiong
- Eye Center of Xiangya Hospital, Central South University, Changsha, China
- Hunan Key Laboratory of Ophthalmology, Xiangya Hospital, Central South University, Changsha, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
- *Correspondence: Siqi Xiong
| | - Xiaobo Xia
- Eye Center of Xiangya Hospital, Central South University, Changsha, China
- Hunan Key Laboratory of Ophthalmology, Xiangya Hospital, Central South University, Changsha, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
- Xiaobo Xia
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43
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Zalckvar E, Schuldiner M. Beyond rare disorders: A new era for peroxisomal pathophysiology. Mol Cell 2022; 82:2228-2235. [PMID: 35714584 DOI: 10.1016/j.molcel.2022.05.028] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Revised: 04/29/2022] [Accepted: 05/23/2022] [Indexed: 12/17/2022]
Abstract
Metabolism is emerging as a central influencer of multiple disease states in humans. Peroxisomes are central metabolic organelles whose decreased function gives rise to severe peroxisomal diseases. Recently, it is becoming clear that, beyond such rare inborn errors, the deterioration of peroxisomal functions contributes to multiple and prevalent diseases such as cancer, viral infection, diabetes, and neurodegeneration. Despite the clear importance of peroxisomes in common pathophysiological processes, research on the mechanisms underlying their contributions is still sparse. Here, we highlight the timeliness of focusing on peroxisomes in current research on central, abundant, and society-impacting human pathologies. As peroxisomes are now coming into the spotlight, it is clear that intensive research into these important organelles will enable a better understanding of their contribution to human health, serving as the basis to develop new diagnostic and therapeutic approaches to prevent and treat human diseases.
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Affiliation(s)
- Einat Zalckvar
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel.
| | - Maya Schuldiner
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel.
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44
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Emilsson V, Gudmundsson EF, Jonmundsson T, Jonsson BG, Twarog M, Gudmundsdottir V, Li Z, Finkel N, Poor S, Liu X, Esterberg R, Zhang Y, Jose S, Huang CL, Liao SM, Loureiro J, Zhang Q, Grosskreutz CL, Nguyen AA, Huang Q, Leehy B, Pitts R, Aspelund T, Lamb JR, Jonasson F, Launer LJ, Cotch MF, Jennings LL, Gudnason V, Walshe TE. A proteogenomic signature of age-related macular degeneration in blood. Nat Commun 2022; 13:3401. [PMID: 35697682 PMCID: PMC9192739 DOI: 10.1038/s41467-022-31085-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 06/01/2022] [Indexed: 12/28/2022] Open
Abstract
Age-related macular degeneration (AMD) is one of the most common causes of visual impairment in the elderly, with a complex and still poorly understood etiology. Whole-genome association studies have discovered 34 genomic regions associated with AMD. However, the genes and cognate proteins that mediate the risk, are largely unknown. In the current study, we integrate levels of 4782 human serum proteins with all genetic risk loci for AMD in a large population-based study of the elderly, revealing many proteins and pathways linked to the disease. Serum proteins are also found to reflect AMD severity independent of genetics and predict progression from early to advanced AMD after five years in this population. A two-sample Mendelian randomization study identifies several proteins that are causally related to the disease and are directionally consistent with the observational estimates. In this work, we present a robust and unique framework for elucidating the pathobiology of AMD. Age related macular degeneration is a common cause of visual impairment in the elderly, but the etiology is not fully understood. Here, the authors use genetic data, serum proteomics, and AMD phenotypic data from a large Icelandic cohort to discover proteins altered in, causally related to AMD or signifying progression of advanced AMD.
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Affiliation(s)
- Valur Emilsson
- Icelandic Heart Association, Holtasmari 1, IS-201, Kopavogur, Iceland. .,Faculty of Medicine, University of Iceland, 101, Reykjavik, Iceland.
| | | | | | | | - Michael Twarog
- Novartis Institutes for Biomedical Research, 22 Windsor Street, Cambridge, MA, 02139, USA
| | - Valborg Gudmundsdottir
- Icelandic Heart Association, Holtasmari 1, IS-201, Kopavogur, Iceland.,Faculty of Medicine, University of Iceland, 101, Reykjavik, Iceland
| | - Zhiguang Li
- Laboratory of Epidemiology and Population Sciences, National Institute on Aging, Bethesda, MD, USA
| | - Nancy Finkel
- Novartis Institutes for Biomedical Research, 22 Windsor Street, Cambridge, MA, 02139, USA
| | - Stephen Poor
- Novartis Institutes for Biomedical Research, 22 Windsor Street, Cambridge, MA, 02139, USA
| | - Xin Liu
- Novartis Institutes for Biomedical Research, 22 Windsor Street, Cambridge, MA, 02139, USA
| | - Robert Esterberg
- Novartis Institutes for Biomedical Research, 22 Windsor Street, Cambridge, MA, 02139, USA
| | - Yiyun Zhang
- Novartis Institutes for Biomedical Research, 22 Windsor Street, Cambridge, MA, 02139, USA
| | - Sandra Jose
- Novartis Institutes for Biomedical Research, 22 Windsor Street, Cambridge, MA, 02139, USA
| | - Chia-Ling Huang
- Novartis Institutes for Biomedical Research, 22 Windsor Street, Cambridge, MA, 02139, USA
| | - Sha-Mei Liao
- Novartis Institutes for Biomedical Research, 22 Windsor Street, Cambridge, MA, 02139, USA
| | - Joseph Loureiro
- Novartis Institutes for Biomedical Research, 22 Windsor Street, Cambridge, MA, 02139, USA
| | - Qin Zhang
- Novartis Institutes for Biomedical Research, 22 Windsor Street, Cambridge, MA, 02139, USA
| | - Cynthia L Grosskreutz
- Novartis Institutes for Biomedical Research, 22 Windsor Street, Cambridge, MA, 02139, USA
| | - Andrew A Nguyen
- Novartis Institutes for Biomedical Research, 22 Windsor Street, Cambridge, MA, 02139, USA
| | - Qian Huang
- Novartis Institutes for Biomedical Research, 22 Windsor Street, Cambridge, MA, 02139, USA
| | - Barrett Leehy
- Novartis Institutes for Biomedical Research, 22 Windsor Street, Cambridge, MA, 02139, USA
| | - Rebecca Pitts
- Novartis Institutes for Biomedical Research, 22 Windsor Street, Cambridge, MA, 02139, USA
| | - Thor Aspelund
- Icelandic Heart Association, Holtasmari 1, IS-201, Kopavogur, Iceland
| | - John R Lamb
- Novartis Institutes for Biomedical Research, 10675 John Jay Hopkins Drive, San Diego, CA, 92121, USA
| | - Fridbert Jonasson
- Faculty of Medicine, University of Iceland, 101, Reykjavik, Iceland.,Department of Ophthalmology, University Hospital, Reykjavik, Iceland
| | - Lenore J Launer
- Laboratory of Epidemiology and Population Sciences, National Institute on Aging, Bethesda, MD, USA
| | - Mary Frances Cotch
- Division of Epidemiology and Clinical Applications, National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - Lori L Jennings
- Novartis Institutes for Biomedical Research, 22 Windsor Street, Cambridge, MA, 02139, USA
| | - Vilmundur Gudnason
- Icelandic Heart Association, Holtasmari 1, IS-201, Kopavogur, Iceland.,Faculty of Medicine, University of Iceland, 101, Reykjavik, Iceland
| | - Tony E Walshe
- Novartis Institutes for Biomedical Research, 22 Windsor Street, Cambridge, MA, 02139, USA.
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Hanna J, David LA, Touahri Y, Fleming T, Screaton RA, Schuurmans C. Beyond Genetics: The Role of Metabolism in Photoreceptor Survival, Development and Repair. Front Cell Dev Biol 2022; 10:887764. [PMID: 35663397 PMCID: PMC9157592 DOI: 10.3389/fcell.2022.887764] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Accepted: 04/19/2022] [Indexed: 12/11/2022] Open
Abstract
Vision commences in the retina with rod and cone photoreceptors that detect and convert light to electrical signals. The irreversible loss of photoreceptors due to neurodegenerative disease leads to visual impairment and blindness. Interventions now in development include transplanting photoreceptors, committed photoreceptor precursors, or retinal pigment epithelial (RPE) cells, with the latter protecting photoreceptors from dying. However, introducing exogenous human cells in a clinical setting faces both regulatory and supply chain hurdles. Recent work has shown that abnormalities in central cell metabolism pathways are an underlying feature of most neurodegenerative disorders, including those in the retina. Reversal of key metabolic alterations to drive retinal repair thus represents a novel strategy to treat vision loss based on cell regeneration. Here, we review the connection between photoreceptor degeneration and alterations in cell metabolism, along with new insights into how metabolic reprogramming drives both retinal development and repair following damage. The potential impact of metabolic reprogramming on retinal regeneration is also discussed, specifically in the context of how metabolic switches drive both retinal development and the activation of retinal glial cells known as Müller glia. Müller glia display latent regenerative properties in teleost fish, however, their capacity to regenerate new photoreceptors has been lost in mammals. Thus, re-activating the regenerative properties of Müller glia in mammals represents an exciting new area that integrates research into developmental cues, central metabolism, disease mechanisms, and glial cell biology. In addition, we discuss this work in relation to the latest insights gleaned from other tissues (brain, muscle) and regenerative species (zebrafish).
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Affiliation(s)
- Joseph Hanna
- Sunnybrook Research Institute, Biological Sciences, Toronto, ON, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada
- Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, ON, Canada
| | - Luke Ajay David
- Sunnybrook Research Institute, Biological Sciences, Toronto, ON, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada
- Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, ON, Canada
| | - Yacine Touahri
- Sunnybrook Research Institute, Biological Sciences, Toronto, ON, Canada
- Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, ON, Canada
- Department of Biochemistry, University of Toronto, Toronto, ON, Canada
| | - Taylor Fleming
- Sunnybrook Research Institute, Biological Sciences, Toronto, ON, Canada
| | - Robert A. Screaton
- Sunnybrook Research Institute, Biological Sciences, Toronto, ON, Canada
- Department of Biochemistry, University of Toronto, Toronto, ON, Canada
| | - Carol Schuurmans
- Sunnybrook Research Institute, Biological Sciences, Toronto, ON, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada
- Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, ON, Canada
- Department of Biochemistry, University of Toronto, Toronto, ON, Canada
- *Correspondence: Carol Schuurmans,
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46
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Nutraceuticals/Drugs Promoting Mitophagy and Mitochondrial Biogenesis May Combat the Mitochondrial Dysfunction Driving Progression of Dry Age-Related Macular Degeneration. Nutrients 2022; 14:nu14091985. [PMID: 35565950 PMCID: PMC9104458 DOI: 10.3390/nu14091985] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2022] [Revised: 04/29/2022] [Accepted: 05/04/2022] [Indexed: 02/07/2023] Open
Abstract
In patients with age-related macular degeneration (AMD), the crucial retinal pigment epithelial (RPE) cells are characterized by mitochondria that are structurally and functionally defective. Moreover, deficient expression of the mRNA-editing enzyme Dicer is noted specifically in these cells. This Dicer deficit up-regulates expression of Alu RNA, which in turn damages mitochondria—inducing the loss of membrane potential, boosting oxidant generation, and causing mitochondrial DNA to translocate to the cytoplasmic region. The cytoplasmic mtDNA, in conjunction with induced oxidative stress, triggers a non-canonical pathway of NLRP3 inflammasome activation, leading to the production of interleukin-18 that acts in an autocrine manner to induce apoptotic death of RPE cells, thereby driving progression of dry AMD. It is proposed that measures which jointly up-regulate mitophagy and mitochondrial biogenesis (MB), by replacing damaged mitochondria with “healthy” new ones, may lessen the adverse impact of Alu RNA on RPE cells, enabling the prevention or control of dry AMD. An analysis of the molecular biology underlying mitophagy/MB and inflammasome activation suggests that nutraceuticals or drugs that can activate Sirt1, AMPK, Nrf2, and PPARα may be useful in this regard. These include ferulic acid, melatonin urolithin A and glucosamine (Sirt1), metformin and berberine (AMPK), lipoic acid and broccoli sprout extract (Nrf2), and fibrate drugs and astaxanthin (PPARα). Hence, nutraceutical regimens providing physiologically meaningful doses of several or all of the: ferulic acid, melatonin, glucosamine, berberine, lipoic acid, and astaxanthin, may have potential for control of dry AMD.
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47
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Salimiaghdam N, Singh L, Singh MK, Chwa M, Atilano SR, Mohtashami Z, Nesburn AB, Kuppermann BD, Lu SY, Kenney MC. Impacts of Bacteriostatic and Bactericidal Antibiotics on the Mitochondria of the Age-Related Macular Degeneration Cybrid Cell Lines. Biomolecules 2022; 12:675. [PMID: 35625603 PMCID: PMC9138285 DOI: 10.3390/biom12050675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2022] [Revised: 04/29/2022] [Accepted: 05/03/2022] [Indexed: 12/07/2022] Open
Abstract
We assessed the potential negative effects of bacteriostatic and bactericidal antibiotics on the AMD cybrid cell lines (K, U and J haplogroups). AMD cybrid cells were created and cultured in 96-well plates and treated with tetracycline (TETRA) and ciprofloxacin (CPFX) for 24 h. Reactive oxygen species (ROS) levels, mitochondrial membrane potential (ΔψM), cellular metabolism and ratio of apoptotic cells were measured using H2DCFDA, JC1, MTT and flow cytometry assays, respectively. Expression of genes of antioxidant enzymes, and pro-inflammatory and pro-apoptotic pathways were evaluated by quantitative real-time PCR (qRT-PCR). Higher ROS levels were found in U haplogroup cybrids when treated with CPFX 60 µg/mL concentrations, lower ΔψM of all haplogroups by CPFX 120 µg/mL, diminished cellular metabolism in all cybrids with CPFX 120 µg/mL, and higher ratio of dead cells in K and J cybrids. CPFX 120 µg/mL induced overexpression of IL-33, CASP-3 and CASP-9 in all cybrids, upregulation of TGF-β1 and SOD2 in U and J cybrids, respectively, along with decreased expression of IL-6 in J cybrids. TETRA 120 µg/mL induced decreased ROS levels in U and J cybrids, increased cellular metabolism of treated U cybrids, higher ratio of dead cells in K and J cybrids and declined ΔψM via all TETRA concentrations in all haplogroups. TETRA 120 µg/mL caused upregulation of IL-6 and CASP-3 genes in all cybrids, higher CASP-7 gene expression in K and U cybrids and downregulation of the SOD3 gene in K and U cybrids. Clinically relevant dosages of ciprofloxacin and tetracycline have potential adverse impacts on AMD cybrids possessing K, J and U mtDNA haplogroups in vitro.
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Affiliation(s)
- Nasim Salimiaghdam
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California Irvine, Irvine, CA 92697, USA; (N.S.); (L.S.); (M.K.S.); (M.C.); (S.R.A.); (Z.M.); (A.B.N.); (B.D.K.); (S.Y.L.)
| | - Lata Singh
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California Irvine, Irvine, CA 92697, USA; (N.S.); (L.S.); (M.K.S.); (M.C.); (S.R.A.); (Z.M.); (A.B.N.); (B.D.K.); (S.Y.L.)
| | - Mithalesh K. Singh
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California Irvine, Irvine, CA 92697, USA; (N.S.); (L.S.); (M.K.S.); (M.C.); (S.R.A.); (Z.M.); (A.B.N.); (B.D.K.); (S.Y.L.)
| | - Marilyn Chwa
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California Irvine, Irvine, CA 92697, USA; (N.S.); (L.S.); (M.K.S.); (M.C.); (S.R.A.); (Z.M.); (A.B.N.); (B.D.K.); (S.Y.L.)
| | - Shari R. Atilano
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California Irvine, Irvine, CA 92697, USA; (N.S.); (L.S.); (M.K.S.); (M.C.); (S.R.A.); (Z.M.); (A.B.N.); (B.D.K.); (S.Y.L.)
| | - Zahra Mohtashami
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California Irvine, Irvine, CA 92697, USA; (N.S.); (L.S.); (M.K.S.); (M.C.); (S.R.A.); (Z.M.); (A.B.N.); (B.D.K.); (S.Y.L.)
| | - Anthony B. Nesburn
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California Irvine, Irvine, CA 92697, USA; (N.S.); (L.S.); (M.K.S.); (M.C.); (S.R.A.); (Z.M.); (A.B.N.); (B.D.K.); (S.Y.L.)
- Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Baruch D. Kuppermann
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California Irvine, Irvine, CA 92697, USA; (N.S.); (L.S.); (M.K.S.); (M.C.); (S.R.A.); (Z.M.); (A.B.N.); (B.D.K.); (S.Y.L.)
| | - Stephanie Y. Lu
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California Irvine, Irvine, CA 92697, USA; (N.S.); (L.S.); (M.K.S.); (M.C.); (S.R.A.); (Z.M.); (A.B.N.); (B.D.K.); (S.Y.L.)
| | - M. Cristina Kenney
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California Irvine, Irvine, CA 92697, USA; (N.S.); (L.S.); (M.K.S.); (M.C.); (S.R.A.); (Z.M.); (A.B.N.); (B.D.K.); (S.Y.L.)
- Department of Pathology and Laboratory Medicine, University of California Irvine, Irvine, CA 92697, USA
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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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49
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Fisher CR, Ebeling MC, Ferrington DA. Quantification of mitophagy using mKeima-mito in cultured human primary retinal pigment epithelial cells. Exp Eye Res 2022; 217:108981. [PMID: 35167864 PMCID: PMC8957530 DOI: 10.1016/j.exer.2022.108981] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Revised: 01/25/2022] [Accepted: 02/04/2022] [Indexed: 11/28/2022]
Abstract
The retinal pigment epithelium is a pigmented monolayer of cells that help maintain a healthy retina. Loss of this essential cell layer is implicated in a number of visual disorders, including age-related macular degeneration (AMD). Utilizing primary RPE cultures to investigate disease is an important step in understanding disease mechanisms. However, the use of primary RPE cultures presents a number of challenges, including the limited number of cells available and the presence of auto-fluorescent pigment that interferes with quantifying fluorescent probes. Additionally, primary RPE are difficult to transfect with exogenous nucleic acids traditionally used for fluorescent imaging. To overcome these challenges, we used an adeno-associated viral (AAV) vector to express a pH sensitive fluorescent protein, mKeima, fused to the mitochondrial targeting sequence of cytochrome oxidase subunit 8A (mKeima-mito). mKeima-mito allows for quantification of mitochondrial autophagy (mitophagy) in live-cell time-lapse imaging experiments. We also developed an image analysis pipeline to selectively quantify mKeima-mito while removing the signal of auto-fluorescent pigment from the dataset by utilizing information from the mKeima fluorescent channels. These techniques are demonstrated in primary RPE cultures expressing mKeima-mito treated with 2-[2-[4-(trifluoromethoxy)phenyl]hydrazinylidene]-propanedinitrile (FCCP), an uncoupler that depolarizes the mitochondrial membrane and leads to mitochondrial fragmentation and mitophagy. The techniques outlined provide a roadmap for investigating disease mechanisms or the effect of treatments utilizing fluorescent probes in an important cell culture model.
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Affiliation(s)
- Cody R Fisher
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, MN, 55455, USA; Graduate Program in Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Mara C Ebeling
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Deborah A Ferrington
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, MN, 55455, USA; Graduate Program in Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN, 55455, USA.
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Ming-Mu-Di-Huang-Pill Activates SQSTM1 via AMPK-Mediated Autophagic KEAP1 Degradation and Protects RPE Cells from Oxidative Damage. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2022; 2022:5851315. [PMID: 35378824 PMCID: PMC8976466 DOI: 10.1155/2022/5851315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/24/2021] [Revised: 01/30/2022] [Accepted: 02/24/2022] [Indexed: 11/18/2022]
Abstract
Oxidative stress and diminished autophagy in the retinal pigment epithelium (RPE) play crucial roles in the pathogenesis of age-related macular degeneration (AMD). Enhancing autophagy has recently been identified as an important strategy to protect RPE cells from oxidative damage. Ming-Mu-Di-Huang-Pill (MMDH pill) is a traditional herbal medicine used to treat AMD, and its molecular mechanism is not well understood. The aim of the present study was to investigate whether the MMDH pill relieved acute oxidative damage by activating autophagy in an in vitro and in vivo model of sodium iodate (NaIO3). The results showed that NaIO3 induced cell death and inhibited proliferation. The MMDH pill increased cell viability, restored the activities of antioxidant enzymes, and reduced reactive oxygen species (ROS) fluorescence intensity. The MMDH pill mediated Kelch-like ECH-associated protein 1 (Keap1) degradation and decreased oxidative damage, which was blocked in autophagy inhibitor (chloroquine) or sequestosome-1 (SQSTM1) siRNA-treated RPE cells. Furthermore, we indicated that the MMDH pill could promote adenosine monophosphate-activated protein kinase (AMPK) phosphorylation and autophagy adaptor-SQSTM1 expression, which could stimulate autophagic degradation of Keap1. In addition, the MMDH pill increased nuclear factor (erythroid-derived 2)-like 2 (Nrf2) nuclear translocation in a SQSTM1-dependent manner and induced the expression of the downstream antioxidant factors heme oxygenase-1 (HO-1) and nicotinamide adenine dinucleotide phosphate quinone dehydrogenase 1 (NQO1). In conclusion, MMDH pill plays a protective role in relieving NaIO3-induced oxidative stress by activating the AMPK/SQSTM1/Keap1 pathway. The MMDH pill may be useful to treat AMD by maintaining redox homeostasis and autophagy.
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