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Ayten M, Díaz-Lezama N, Ghanawi H, Haffelder FC, Kajtna J, Straub T, Borso M, Imhof A, Hauck SM, Koch SF. Metabolic plasticity in a Pde6b STOP/STOP retinitis pigmentosa mouse model following rescue. Mol Metab 2024:101994. [PMID: 39032643 DOI: 10.1016/j.molmet.2024.101994] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/16/2024] [Revised: 06/18/2024] [Accepted: 07/13/2024] [Indexed: 07/23/2024] Open
Abstract
Retinitis pigmentosa (RP) is a hereditary retinal disease characterized by progressive photoreceptor degeneration, leading to vision loss. The best hope for a cure for RP lies in gene therapy. However, given that RP patients are most often diagnosed in the midst of ongoing photoreceptor degeneration, it is important to determine how the retinal proteome changes as RP disease progresses, and to identify which changes can be prevented, halted, or reversed by gene therapy. Here, we used our Pde6b-deficient RP gene therapy mouse model and demonstrated that Pde6b gene restoration led to a novel form of homeostatic plasticity in rod phototransduction which functionally compensates for the decreased number of rods. By profiling protein levels of metabolic genes and measuring metabolites, we observed an upregulation of proteins associated with oxidative phosphorylation in mutant and treated photoreceptors. Thus, the metabolic demands of the retina differ in our Pde6b-deficient RP mouse model and are not rescued by gene therapy treatment. These findings provide novel insights into features of both RP disease progression and long-term rescue with gene therapy.
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Affiliation(s)
- Monika Ayten
- Department of Pharmacy, Center for Drug Research, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Nundehui Díaz-Lezama
- Department of Pharmacy, Center for Drug Research, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Hanaa Ghanawi
- Department of Pharmacy, Center for Drug Research, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Felia C Haffelder
- Department of Pharmacy, Center for Drug Research, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Jacqueline Kajtna
- Department of Pharmacy, Center for Drug Research, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Tobias Straub
- Bioinformatics Unit, Biomedical Center Munich, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Marco Borso
- Molecular Biology, Biomedical Center Munich, Faculty of Medicine, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Axel Imhof
- Molecular Biology, Biomedical Center Munich, Faculty of Medicine, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Stefanie M Hauck
- Metabolomics and Proteomics Core, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany
| | - Susanne F Koch
- Department of Pharmacy, Center for Drug Research, Ludwig-Maximilians-Universität München, Munich, Germany.
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2
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van Noorden CJ, Yetkin-Arik B, Serrano Martinez P, Bakker N, van Breest Smallenburg ME, Schlingemann RO, Klaassen I, Majc B, Habic A, Bogataj U, Galun SK, Vittori M, Erdani Kreft M, Novak M, Breznik B, Hira VV. New Insights in ATP Synthesis as Therapeutic Target in Cancer and Angiogenic Ocular Diseases. J Histochem Cytochem 2024; 72:329-352. [PMID: 38733294 PMCID: PMC11107438 DOI: 10.1369/00221554241249515] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Accepted: 04/01/2024] [Indexed: 05/13/2024] Open
Abstract
Lactate and ATP formation by aerobic glycolysis, the Warburg effect, is considered a hallmark of cancer. During angiogenesis in non-cancerous tissue, proliferating stalk endothelial cells (ECs) also produce lactate and ATP by aerobic glycolysis. In fact, all proliferating cells, both non-cancer and cancer cells, need lactate for the biosynthesis of building blocks for cell growth and tissue expansion. Moreover, both non-proliferating cancer stem cells in tumors and leader tip ECs during angiogenesis rely on glycolysis for pyruvate production, which is used for ATP synthesis in mitochondria through oxidative phosphorylation (OXPHOS). Therefore, aerobic glycolysis is not a specific hallmark of cancer but rather a hallmark of proliferating cells and limits its utility in cancer therapy. However, local treatment of angiogenic eye conditions with inhibitors of glycolysis may be a safe therapeutic option that warrants experimental investigation. Most types of cells in the eye such as photoreceptors and pericytes use OXPHOS for ATP production, whereas proliferating angiogenic stalk ECs rely on glycolysis for lactate and ATP production. (J Histochem Cytochem XX.XXX-XXX, XXXX).
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Affiliation(s)
- Cornelis J.F. van Noorden
- Department of Genetic Toxicology and Cancer Biology, National Institute of Biology, Ljubljana, Slovenia
- Ocular Angiogenesis Group, Amsterdam University Medical Center Location University of Amsterdam, Amsterdam, The Netherlands
| | - Bahar Yetkin-Arik
- Department of Pediatric Pulmonology, Wilhelmina Children’s Hospital, University Medical Center Utrecht, Utrecht, The Netherlands
- Regenerative Medicine Center Utrecht, University Medical Center Utrecht, Utrecht, The Netherlands
- Centre for Living Technologies, Alliance TU/e, WUR, UU, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Paola Serrano Martinez
- Ocular Angiogenesis Group, Amsterdam University Medical Center Location University of Amsterdam, Amsterdam, The Netherlands
| | - Noëlle Bakker
- Ocular Angiogenesis Group, Amsterdam University Medical Center Location University of Amsterdam, Amsterdam, The Netherlands
| | | | - Reinier O. Schlingemann
- Ocular Angiogenesis Group, Amsterdam University Medical Center Location University of Amsterdam, Amsterdam, The Netherlands
- Department of Ophthalmology, Amsterdam University Medical Center Location University of Amsterdam, Amsterdam, The Netherlands
- Department of Ophthalmology, Jules-Gonin Eye Hospital, Fondation Asile des Aveugles, University of Lausanne, Lausanne, Switzerland
| | - Ingeborg Klaassen
- Ocular Angiogenesis Group, Amsterdam University Medical Center Location University of Amsterdam, Amsterdam, The Netherlands
| | - Bernarda Majc
- Department of Genetic Toxicology and Cancer Biology, National Institute of Biology, Ljubljana, Slovenia
| | - Anamarija Habic
- Department of Genetic Toxicology and Cancer Biology, National Institute of Biology, Ljubljana, Slovenia
- Jozef Stefan Postgraduate School, Ljubljana, Slovenia
| | - Urban Bogataj
- Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
| | - S. Katrin Galun
- Department of Genetic Toxicology and Cancer Biology, National Institute of Biology, Ljubljana, Slovenia
| | - Milos Vittori
- Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
| | - Mateja Erdani Kreft
- Institute of Cell Biology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Metka Novak
- Department of Genetic Toxicology and Cancer Biology, National Institute of Biology, Ljubljana, Slovenia
| | - Barbara Breznik
- Department of Genetic Toxicology and Cancer Biology, National Institute of Biology, Ljubljana, Slovenia
| | - Vashendriya V.V. Hira
- Department of Genetic Toxicology and Cancer Biology, National Institute of Biology, Ljubljana, Slovenia
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3
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Sun GF, Qu XH, Jiang LP, Chen ZP, Wang T, Han XJ. The mechanisms of natural products for eye disorders by targeting mitochondrial dysfunction. Front Pharmacol 2024; 15:1270073. [PMID: 38725662 PMCID: PMC11079200 DOI: 10.3389/fphar.2024.1270073] [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: 07/31/2023] [Accepted: 04/10/2024] [Indexed: 05/12/2024] Open
Abstract
The human eye is susceptible to various disorders that affect its structure or function, including glaucoma, age-related macular degeneration (AMD) and diabetic retinopathy (DR). Mitochondrial dysfunction has been identified as a critical factor in the pathogenesis and progression of eye disorders, making it a potential therapeutic target in the clinic. Natural products have been used in traditional medicine for centuries and continue to play a significant role in modern drug development and clinical therapeutics. Recently, there has been a surge in research exploring the efficacy of natural products in treating eye disorders and their underlying physiological mechanisms. This review aims to discuss the involvement of mitochondrial dysfunction in eye disorders and summarize the recent advances in the application of natural products targeting mitochondria. In addition, we describe the future perspective and challenges in the development of mitochondria-targeting natural products.
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Affiliation(s)
- Gui-Feng Sun
- Institute of Geriatrics, Jiangxi Provincial People’s Hospital, The First Affiliated Hospital of Nanchang Medical College, Nanchang, China
- Department of Pharmacology, School of Pharmaceutical Science, Nanchang University, Nanchang, China
| | - Xin-Hui Qu
- Institute of Geriatrics, Jiangxi Provincial People’s Hospital, The First Affiliated Hospital of Nanchang Medical College, Nanchang, China
- The Second Department of Neurology, Jiangxi Provincial People’s Hospital, The First Affiliated Hospital of Nanchang Medical College, Nanchang, China
| | - Li-Ping Jiang
- Department of Pharmacology, School of Pharmaceutical Science, Nanchang University, Nanchang, China
| | - Zhi-Ping Chen
- Department of Critical Care Medicine, Jiangxi Provincial People’s Hospital, The First Affiliated Hospital of Nanchang Medical College, Nanchang, China
| | - Tao Wang
- Institute of Geriatrics, Jiangxi Provincial People’s Hospital, The First Affiliated Hospital of Nanchang Medical College, Nanchang, China
| | - Xiao-Jian Han
- Institute of Geriatrics, Jiangxi Provincial People’s Hospital, The First Affiliated Hospital of Nanchang Medical College, Nanchang, China
- The Second Department of Neurology, Jiangxi Provincial People’s Hospital, The First Affiliated Hospital of Nanchang Medical College, Nanchang, China
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4
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Yao Y, Chen Z, Wu Q, Lu Y, Zhou X, Zhu X. Single-cell RNA sequencing of retina revealed novel transcriptional landscape in high myopia and underlying cell-type-specific mechanisms. MedComm (Beijing) 2023; 4:e372. [PMID: 37746666 PMCID: PMC10511833 DOI: 10.1002/mco2.372] [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: 03/17/2023] [Revised: 08/16/2023] [Accepted: 08/24/2023] [Indexed: 09/26/2023] Open
Abstract
High myopia is a leading cause of blindness worldwide with increasing prevalence. Retina percepts visual information and triggers myopia development, but the underlying etiology is not fully understood because of cellular heterogeneity. In this study, single-cell RNA sequencing analysis was performed on retinas of mouse highly myopic and control eyes to dissect the involvement of each cell type during high myopia progression. For highly myopic photoreceptors, Hk2 inhibition underlying metabolic remodeling from aerobic glycolysis toward oxidative phosphorylation and excessive oxidative stress was identified. Importantly, a novel Apoe + rod subpopulation was specifically identified in highly myopic retina. In retinal neurons of highly myopic eyes, neurodegeneration was generally discovered, and the imbalanced ON/OFF signaling driven by cone-bipolar cells and the downregulated dopamine receptors in amacrine cells were among the most predominant findings, indicating the aberrant light processing in highly myopic eyes. Besides, microglia exhibited elevated expression of cytokines and TGF-β receptors, suggesting enhanced responses to inflammation and the growth-promoting states involved in high myopia progression. Furthermore, cell-cell communication network revealed attenuated neuronal interactions and increased glial/vascular interactions in highly myopic retinas. In conclusion, this study outlines the transcriptional landscape of highly myopic retina, providing novel insights into high myopia development and prevention.
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Affiliation(s)
- Yunqian Yao
- Eye Institute and Department of OphthalmologyEye & ENT HospitalFudan UniversityShanghaiChina
- Key Laboratory of MyopiaChinese Academy of Medical SciencesNational Health Center Key Laboratory of Myopia (Fudan University)ShanghaiChina
- Shanghai Research Center of Ophthalmology and OptometryShanghaiChina
| | - Zhenhua Chen
- State Key Laboratory of Molecular Development BiologyChinese Academy of SciencesInstitute of Genetics and Developmental BiologyBeijingChina
- University of Chinese Academy of SciencesBeijingChina
| | - Qingfeng Wu
- State Key Laboratory of Molecular Development BiologyChinese Academy of SciencesInstitute of Genetics and Developmental BiologyBeijingChina
- University of Chinese Academy of SciencesBeijingChina
- Center for Excellence in Brain Science and Intelligence TechnologyChinese Academy of SciencesBeijingChina
- Chinese Institute for Brain ResearchBeijingChina
- Beijing Children's HospitalCapital Medical UniversityBeijingChina
| | - Yi Lu
- Eye Institute and Department of OphthalmologyEye & ENT HospitalFudan UniversityShanghaiChina
- Key Laboratory of MyopiaChinese Academy of Medical SciencesNational Health Center Key Laboratory of Myopia (Fudan University)ShanghaiChina
- Shanghai Key Laboratory of Visual Impairment and RestorationShanghaiChina
- State Key Laboratory of Medical NeurobiologyFudan UniversityShanghaiChina
| | - Xingtao Zhou
- Eye Institute and Department of OphthalmologyEye & ENT HospitalFudan UniversityShanghaiChina
- Key Laboratory of MyopiaChinese Academy of Medical SciencesNational Health Center Key Laboratory of Myopia (Fudan University)ShanghaiChina
- Shanghai Research Center of Ophthalmology and OptometryShanghaiChina
| | - Xiangjia Zhu
- Eye Institute and Department of OphthalmologyEye & ENT HospitalFudan UniversityShanghaiChina
- Key Laboratory of MyopiaChinese Academy of Medical SciencesNational Health Center Key Laboratory of Myopia (Fudan University)ShanghaiChina
- Shanghai Key Laboratory of Visual Impairment and RestorationShanghaiChina
- State Key Laboratory of Medical NeurobiologyFudan UniversityShanghaiChina
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5
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Su L, Gong X, Fan R, Ni T, Yang F, Zhang X, Li X. Mechanism of action of platinum nanoparticles implying from antioxidant to metabolic programming in light-induced retinal degeneration model. Redox Biol 2023; 65:102836. [PMID: 37541055 PMCID: PMC10412868 DOI: 10.1016/j.redox.2023.102836] [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: 07/07/2023] [Revised: 07/24/2023] [Accepted: 07/31/2023] [Indexed: 08/06/2023] Open
Abstract
Photoreceptors (PRs) degeneration is central to visual impairment and loss in most blind retinal diseases, including age-related macular disease (AMD) and diabetic retinopathy (DR). PRs are susceptible to oxidative stress owing to their unique metabolic features. Accumulating evidence has demonstrated that the targeting oxidative stress is a promising treatment strategy for PR degeneration. Herein, we introduced potent antioxidative platinum nanoparticles (Pt NPs) to treat PRs degeneration in this study. The Pt NPs exhibited multi-enzymatic antioxidant activity and protected PRs from H2O2-induced oxidative damage in vitro assays. Based on the same mechanism, the intravitreal injection of Pt NPs significantly reduced cell apoptosis, maintained retinal structure and preserved retinal function in a mouse model of light-induced retinal degeneration (LIRD). Most importantly, the results of RNA sequencing showed that the transcription of antioxidative genes was upregulated, and metabolic reprogramming occurred in the LIRD-retina after treatment with Pt NPs, both of which benefited retinal survival from oxidative damage. The results indicated that Pt NPs were indeed potent therapeutic candidates for PRs degeneration in blind retinal diseases.
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Affiliation(s)
- Lin Su
- Tianjin Key Laboratory of Retinal Functions and Diseases, Tianjin Branch of National Clinical Research Center for Ocular Disease, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital, No. 251, Fukang Road, Nankai District, Tianjin, 300384, China
| | - Xiaoqun Gong
- School of Life Sciences, Tianjin Engineering Center of Micro-Nano Biomaterials and Detection-Treatment Technology, Collaborative Innovation Center of Chemical Science and Engineering, Tianjin University, Tianjin, 300072, PR China.
| | - Ruiyan Fan
- Tianjin Key Laboratory of Retinal Functions and Diseases, Tianjin Branch of National Clinical Research Center for Ocular Disease, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital, No. 251, Fukang Road, Nankai District, Tianjin, 300384, China
| | - Tianwen Ni
- Tianjin Key Laboratory of Retinal Functions and Diseases, Tianjin Branch of National Clinical Research Center for Ocular Disease, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital, No. 251, Fukang Road, Nankai District, Tianjin, 300384, China
| | - Fuhua Yang
- Tianjin Key Laboratory of Retinal Functions and Diseases, Tianjin Branch of National Clinical Research Center for Ocular Disease, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital, No. 251, Fukang Road, Nankai District, Tianjin, 300384, China
| | - Xiaomin Zhang
- Tianjin Key Laboratory of Retinal Functions and Diseases, Tianjin Branch of National Clinical Research Center for Ocular Disease, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital, No. 251, Fukang Road, Nankai District, Tianjin, 300384, China.
| | - Xiaorong Li
- Tianjin Key Laboratory of Retinal Functions and Diseases, Tianjin Branch of National Clinical Research Center for Ocular Disease, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital, No. 251, Fukang Road, Nankai District, Tianjin, 300384, China.
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6
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Tan Y, Huang J, Li D, Zou C, Liu D, Qin B. Single-cell RNA sequencing in dissecting microenvironment of age-related macular degeneration: Challenges and perspectives. Ageing Res Rev 2023; 90:102030. [PMID: 37549871 DOI: 10.1016/j.arr.2023.102030] [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: 09/16/2022] [Revised: 04/29/2023] [Accepted: 08/04/2023] [Indexed: 08/09/2023]
Abstract
Age-related macular degeneration (AMD) is the leading cause of blindness in individuals over the age of 50 years, yet its etiology and pathogenesis largely remain uncovered. Single-cell RNA sequencing (scRNA-seq) technologies are recently developed and have a number of advantages over conventional bulk RNA sequencing techniques in uncovering the heterogeneity of complex microenvironments containing numerous cell types and cell communications during various biological processes. In this review, we summarize the latest discovered cellular components and regulatory mechanisms during AMD development revealed by scRNA-seq. In addition, we discuss the main challenges and future directions in exploring the pathophysiology of AMD equipped with single-cell technologies. Our review underscores the importance of multimodal single-cell platforms (such as single-cell spatiotemporal multi-omics and single-cell exosome omics) as new approaches for basic and clinical AMD research in identifying biomarker, characterizing cellular responses to drug treatment and environmental stimulation.
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Affiliation(s)
- Yao Tan
- Shenzhen Aier Eye Hospital, Aier Eye Hospital, Jinan University, Shenzhen, China
| | - Jianguo Huang
- Shenzhen Aier Eye Hospital, Aier Eye Hospital, Jinan University, Shenzhen, China
| | - Deshuang Li
- Shenzhen Aier Eye Hospital, Aier Eye Hospital, Jinan University, Shenzhen, China
| | - Chang Zou
- Shenzhen Aier Eye Hospital, Aier Eye Hospital, Jinan University, Shenzhen, China; Shenzhen Aier Ophthalmic Technology Institute, Shenzhen, China; School of Life and Health Sciences, The Chinese University of Kong Hong, Shenzhen 518000, Guangdong, China.
| | - Dongcheng Liu
- Shenzhen Aier Eye Hospital, Aier Eye Hospital, Jinan University, Shenzhen, China; Shenzhen Aier Ophthalmic Technology Institute, Shenzhen, China.
| | - Bo Qin
- Shenzhen Aier Eye Hospital, Aier Eye Hospital, Jinan University, Shenzhen, China; Shenzhen Aier Ophthalmic Technology Institute, Shenzhen, China; Aier School of Ophthalmology, Central South University, Changsha, China.
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7
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Dobreva A, Camacho ET, Miranda M. Mathematical model for glutathione dynamics in the retina. Sci Rep 2023; 13:10996. [PMID: 37419948 PMCID: PMC10328985 DOI: 10.1038/s41598-023-37938-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Accepted: 06/29/2023] [Indexed: 07/09/2023] Open
Abstract
The retina is highly susceptible to the generation of toxic reactive oxygen species (ROS) that disrupt the normal operations of retinal cells. The glutathione (GSH) antioxidant system plays an important role in mitigating ROS. To perform its protective functions, GSH depends on nicotinamide adenine dinucleotide phosphate (NADPH) produced through the pentose phosphate pathway. This work develops the first mathematical model for the GSH antioxidant system in the outer retina, capturing the most essential components for formation of ROS, GSH production, its oxidation in detoxifying ROS, and subsequent reduction by NADPH. We calibrate and validate the model using experimental measurements, at different postnatal days up to PN28, from control mice and from the rd1 mouse model for the disease retinitis pigmentosa (RP). Global sensitivity analysis is then applied to examine the model behavior and identify the pathways with the greatest impact in control compared to RP conditions. The findings underscore the importance of GSH and NADPH production in dealing with oxidative stress during retinal development, especially after peak rod degeneration occurs in RP, leading to increased oxygen tension. This suggests that stimulation of GSH and NADPH synthesis could be a potential intervention strategy in degenerative mouse retinas with RP.
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Affiliation(s)
- Atanaska Dobreva
- Department of Mathematics, Augusta University, Augusta, GA, 30912, USA.
| | - Erika Tatiana Camacho
- University of Texas at San Antonio, San Antonio, TX, 78249, USA
- School of Mathematical and Statistical Sciences, Arizona State University, Tempe, AZ, 85281, USA
| | - María Miranda
- Department of Biomedical Sciences, Faculty of Health Sciences, Institute of Biomedical Sciences, Cardenal Herrera-CEU University, CEU Universities, 46115, Valencia, Spain
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8
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Wang X, Chen C, Zhu L, Shi K, Peng B, Zhu Y, Mao H, Long H, Ke S, Fu C, Zhu Y, Wan C, Wan Q. Vertically integrated spiking cone photoreceptor arrays for color perception. Nat Commun 2023; 14:3444. [PMID: 37301894 PMCID: PMC10257685 DOI: 10.1038/s41467-023-39143-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Accepted: 05/31/2023] [Indexed: 06/12/2023] Open
Abstract
The cone photoreceptors in our eyes selectively transduce the natural light into spiking representations, which endows the brain with high energy-efficiency color vision. However, the cone-like device with color-selectivity and spike-encoding capability remains challenging. Here, we propose a metal oxide-based vertically integrated spiking cone photoreceptor array, which can directly transduce persistent lights into spike trains at a certain rate according to the input wavelengths. Such spiking cone photoreceptors have an ultralow power consumption of less than 400 picowatts per spike in visible light, which is very close to biological cones. In this work, lights with three wavelengths were exploited as pseudo-three-primary colors to form 'colorful' images for recognition tasks, and the device with the ability to discriminate mixed colors shows better accuracy. Our results would enable hardware spiking neural networks with biologically plausible visual perception and provide great potential for the development of dynamic vision sensors.
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Affiliation(s)
- Xiangjing Wang
- School of Electronic Science and Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Chunsheng Chen
- School of Electronic Science and Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Li Zhu
- College of Integrated Circuit Science and Engineering, Nanjing University of Posts and Telecommunications, Nanjing, 210003, China
| | - Kailu Shi
- School of Electronic Science and Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Baocheng Peng
- School of Electronic Science and Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Yixin Zhu
- School of Electronic Science and Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Huiwu Mao
- School of Electronic Science and Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Haotian Long
- School of Electronic Science and Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Shuo Ke
- School of Electronic Science and Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Chuanyu Fu
- School of Electronic Science and Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Ying Zhu
- School of Electronic Science and Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Changjin Wan
- School of Electronic Science and Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China.
| | - Qing Wan
- School of Electronic Science and Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China.
- School of Micro Nanoelectronics, Zhejiang University, ZJU-Hangzhou Global Scientific and Technological Innovation Centre, 310027, Hangzhou, PR China.
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9
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Song DJ, Bao XL, Fan B, Li GY. Mechanism of Cone Degeneration in Retinitis Pigmentosa. Cell Mol Neurobiol 2023; 43:1037-1048. [PMID: 35792991 DOI: 10.1007/s10571-022-01243-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 06/13/2022] [Indexed: 11/27/2022]
Abstract
Retinitis pigmentosa (RP) is a group of genetic disorders resulting in inherited blindness due to the degeneration of rod and cone photoreceptors. The various mechanisms underlying rod degeneration primarily rely on genetic mutations, leading to night blindness initially. Cones gradually degenerate after rods are almost eliminated, resulting in varying degrees of visual disability and blindness. The mechanism of cone degeneration remains unclear. An understanding of the mechanisms underlying cone degeneration in RP, a highly heterogeneous disease, is essential to develop novel treatments of RP. Herein, we review recent advancements in the five hypotheses of cone degeneration, including oxidative stress, trophic factors, metabolic stress, light damage, and inflammation activation. We also discuss the connection among these theories to provide a better understanding of secondary cone degeneration in RP. Five current mechanisms of cone degenerations in RP Interactions among different pathways are involved in RP.
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Affiliation(s)
- De-Juan Song
- Department of Ophthalmology, The Second Hospital of Jilin University, Changchun, 130000, China
| | - Xiao-Li Bao
- Department of Ophthalmology, The Second Hospital of Jilin University, Changchun, 130000, China
| | - Bin Fan
- Department of Ophthalmology, The Second Hospital of Jilin University, Changchun, 130000, China
| | - Guang-Yu Li
- Department of Ophthalmology, The Second Hospital of Jilin University, Changchun, 130000, China.
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10
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Le D, Son T, Lim JI, Yao X. QUANTITATIVE OPTICAL COHERENCE TOMOGRAPHY REVEALS ROD PHOTORECEPTOR DEGENERATION in EARLY DIABETIC RETINOPATHY. Retina 2022; 42:1442-1449. [PMID: 35316256 PMCID: PMC9329162 DOI: 10.1097/iae.0000000000003473] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE This study is to test the feasibility of optical coherence tomography (OCT) detection of photoreceptor abnormality and to verify that the photoreceptor abnormality is rod predominated in early diabetic retinopathy (DR). METHODS OCT images were acquired from normal eyes, diabetic eyes with no DR, and mild nonproliferative DR (NPDR). Quantitative features, including thickness measurements quantifying band distances and reflectance intensity features among the external limiting membrane, inner segment ellipsoid, interdigitation zone, and retinal pigment epithelium were determined. Comparative OCT analysis of central fovea, parafovea, and perifovea were implemented to verify that the photoreceptor abnormality is rod predominated in early DR. RESULTS Thickness abnormalities between the inner segment ellipsoid and interdigitation zone also showed a decreasing trend among cohorts. Reflectance abnormalities of the external limiting membrane, interdigitation zone, and inner segment ellipsoid were observed between healthy, no DR, and mild NPDR eyes. The normalized inner segment ellipsoid/retinal pigment epithelium intensity ratio revealed a significant decreasing trend in the perifovea, but no detectable difference in central fovea. CONCLUSION Quantitative OCT analysis consistently revealed outer retina, i.e., photoreceptor changes in diabetic patients with no DR and mild NPDR. Comparative analysis of central fovea, parafovea, and perifovea confirmed that the photoreceptor abnormality is rod-predominated in early DR.
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Affiliation(s)
- David Le
- Department of Biomedical Engineering, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Taeyoon Son
- Department of Biomedical Engineering, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Jennifer I. Lim
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Xincheng Yao
- Department of Biomedical Engineering, University of Illinois at Chicago, Chicago, IL 60607, USA
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, IL 60612, USA
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11
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Ziaka K, van der Spuy J. The Role of Hsp90 in Retinal Proteostasis and Disease. Biomolecules 2022; 12:biom12070978. [PMID: 35883534 PMCID: PMC9313453 DOI: 10.3390/biom12070978] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 07/07/2022] [Accepted: 07/08/2022] [Indexed: 11/24/2022] Open
Abstract
Photoreceptors are sensitive neuronal cells with great metabolic demands, as they are responsible for carrying out visual phototransduction, a complex and multistep process that requires the exquisite coordination of a large number of signalling protein components. Therefore, the viability of photoreceptors relies on mechanisms that ensure a well-balanced and functional proteome that maintains the protein homeostasis, or proteostasis, of the cell. This review explores how the different isoforms of Hsp90, including the cytosolic Hsp90α/β, the mitochondrial TRAP1, and the ER-specific GRP94, are involved in the different proteostatic mechanisms of photoreceptors, and elaborates on Hsp90 function when retinal homeostasis is disturbed. In addition, several studies have shown that chemical manipulation of Hsp90 has significant consequences, both in healthy and degenerating retinae, and this can be partially attributed to the fact that Hsp90 interacts with important photoreceptor-associated client proteins. Here, the interaction of Hsp90 with the retina-specific client proteins PDE6 and GRK1 will be further discussed, providing additional insights for the role of Hsp90 in retinal disease.
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12
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Aparicio A, Camacho ET, Philp NJ, Wirkus SA. A mathematical model of GLUT1 modulation in rods and RPE and its differential impact in cell metabolism. Sci Rep 2022; 12:10645. [PMID: 35739198 PMCID: PMC9226191 DOI: 10.1038/s41598-022-13950-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Accepted: 05/31/2022] [Indexed: 11/10/2022] Open
Abstract
We present a mathematical model of key glucose metabolic pathways in two cells of the human retina: the rods and the retinal pigmented epithelium (RPE). Computational simulations of glucose transporter 1 (GLUT1) inhibition in the model accurately reproduce experimental data from conditional knockout mice and reveal that modification of GLUT1 expression levels of both cells differentially impacts their metabolism. We hypothesize that, under glucose scarcity, the RPE's energy producing pathways are altered in order to preserve its functionality, impacting the photoreceptors' outer segment renewal. On the other hand, when glucose is limited in the rods, aerobic glycolysis is preserved, which maintains the lactate contribution to the RPE.
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Affiliation(s)
- Andrea Aparicio
- School of Mathematical and Natural Sciences, Arizona State University, Glendale, AZ, USA.
| | - Erika T Camacho
- School of Mathematical and Natural Sciences, Arizona State University, Glendale, AZ, USA
| | - Nancy J Philp
- Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA, USA
| | - Stephen A Wirkus
- School of Mathematical and Natural Sciences, Arizona State University, Glendale, AZ, USA
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13
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Hu K, Lv L, Huang H, Yin G, Gao J, Liu J, Yang Y, Zeng W, Chen Y, Zhang N, Zhang F, Ma Y, Chen F. A Novel Tree Shrew Model of Chronic Experimental Autoimmune Uveitis and Its Disruptive Application. Front Immunol 2022; 13:889596. [PMID: 35711454 PMCID: PMC9196886 DOI: 10.3389/fimmu.2022.889596] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Accepted: 04/29/2022] [Indexed: 11/27/2022] Open
Abstract
Background Previous studies have established several animal models for experimental autoimmune uveitis (EAU) in rodents without the fovea centralis in the human retina. This study aimed to develop and explore the application of a novel EAU model in tree shrews with a cone-dominated retina resembling the human fovea. Methods Tree shrews were clinically and pathologically evaluated for the development and characteristics of EAU immunized with six inter-photoreceptor retinoid-binding proteins (IRBPs). IRBP-specific T-cell proliferation and serum cytokine of tree shrews were evaluated to determine the immune responses. Differentially expressed genes (DEGs) were identified in the eyes of tree shrews with EAU by RNA-sequencing. The disruptive effects of the DEG RGS4 inhibitor CCG 203769 and dihydroartemisinin on the EAU were investigated to evaluate the potential application of tree shrew EAU. Results IRBP1197–1211 and R14 successfully induced chronic EAU with subretinal deposits and retinal damage in the tree shrews. The immunological characteristics presented the predominant infiltration of microglia/macrophages, dendritic cells, and CD4-T-cells into the uvea and retina and pathogenic T helper (Th) 1 and Th17 responses. The subretinal deposits positively expressed amyloid β-protein (Aβ), CD8, and P2Y purinoceptor 12 (P2RY12). The crucial DEGs in R14-induced EAU, such as P2RY2 and adenylate cyclase 4 (ADCY4), were enriched for several pathways, including inflammatory mediator regulation of transient receptor potential (TRP) channels. The upregulated RGS4 in IRBP-induced EAU was associated with mitogen-activated protein kinase (MAPK) activity. RGS4 inhibition and dihydroartemisinin could significantly alleviate the retinal pathological injuries of IRBP1197-1211-induced EAU by decreasing the expression of CD4 T-cells. Conclusion Our study provides a novel chronic EAU in tree shrews elicited by bovine R14 and tree shrew IRBP1197-1211 characterized by retinal degeneration, retinal damage with subretinal Aβ deposits and microglia/macrophage infiltration, and T-cell response, probably by altering important pathways and genes related to bacterial invasion, inflammatory pain, microglial phagocytosis, and lipid and glucose metabolism. The findings advance the knowledge of the pathogenesis and therapeutics of the fovea-involved visual disturbance in human uveitis.
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Affiliation(s)
- Kaijiao Hu
- Laboratory Animal Center, Chongqing Medical University, Chongqing, China.,Chongqing Engineering Research Center for Rodent Laboratory Animals, Chongqing, China
| | - Longbao Lv
- Laboratory Animal Center, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, China
| | - Hui Huang
- Laboratory Animal Center, Chongqing Medical University, Chongqing, China.,Chongqing Engineering Research Center for Rodent Laboratory Animals, Chongqing, China
| | - Guangnian Yin
- Laboratory Animal Center, Chongqing Medical University, Chongqing, China.,Chongqing Engineering Research Center for Rodent Laboratory Animals, Chongqing, China.,Department of Clinical Laboratory, the Second Affiliated Hospital of Army Medical University, Chongqing, China
| | - Jie Gao
- Laboratory Animal Center, Chongqing Medical University, Chongqing, China.,Chongqing Engineering Research Center for Rodent Laboratory Animals, Chongqing, China
| | - Jianping Liu
- Department of Pathology, Chongqing Medical University, Chongqing, China
| | - Yaying Yang
- Department of Pathology, Chongqing Medical University, Chongqing, China
| | - Wenxin Zeng
- Laboratory Animal Center, Chongqing Medical University, Chongqing, China.,Chongqing Engineering Research Center for Rodent Laboratory Animals, Chongqing, China
| | - Yan Chen
- Department of Pathology, Chongqing Medical University, Chongqing, China
| | - Ni Zhang
- The First Affiliated Hospital of Chongqing Medical University, Chongqing Eye Institute, Chongqing, China
| | - Feiyan Zhang
- Laboratory Animal Center, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, China
| | - Yuhua Ma
- Laboratory Animal Center, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, China
| | - Feilan Chen
- Laboratory Animal Center, Chongqing Medical University, Chongqing, China.,Chongqing Engineering Research Center for Rodent Laboratory Animals, Chongqing, China
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14
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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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15
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Chen Y, Coorey NJ, Zhang M, Zeng S, Madigan MC, Zhang X, Gillies MC, Zhu L, Zhang T. Metabolism Dysregulation in Retinal Diseases and Related Therapies. Antioxidants (Basel) 2022; 11:antiox11050942. [PMID: 35624805 PMCID: PMC9137684 DOI: 10.3390/antiox11050942] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 05/09/2022] [Accepted: 05/10/2022] [Indexed: 02/08/2023] Open
Abstract
The human retina, which is part of the central nervous system, has exceptionally high energy demands that requires an efficient metabolism of glucose, lipids, and amino acids. Dysregulation of retinal metabolism disrupts local energy supply and redox balance, contributing to the pathogenesis of diverse retinal diseases, including age-related macular degeneration, diabetic retinopathy, inherited retinal degenerations, and Macular Telangiectasia. A better understanding of the contribution of dysregulated metabolism to retinal diseases may provide better therapeutic targets than we currently have.
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Affiliation(s)
- Yingying Chen
- Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu 610017, China;
- Save Sight Institute, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW 2000, Australia; (S.Z.); (M.C.M.); (M.C.G.); (L.Z.)
| | | | - Meixia Zhang
- Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu 610017, China;
- Macular Disease Research Laboratory, Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu 610017, China
- Correspondence: (M.Z.); (T.Z.)
| | - Shaoxue Zeng
- Save Sight Institute, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW 2000, Australia; (S.Z.); (M.C.M.); (M.C.G.); (L.Z.)
| | - Michele C. Madigan
- Save Sight Institute, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW 2000, Australia; (S.Z.); (M.C.M.); (M.C.G.); (L.Z.)
- School of Optometry and Vision Science, University of New South Wales (UNSW), Sydney, NSW 2052, Australia
| | - Xinyuan Zhang
- Department of Ocular Fundus Diseases, Beijing Tongren Eye Centre, Tongren Hospital, Capital Medical University, Beijing 100073, China;
- Beijing Retinal and Choroidal Vascular Study Group, Beijing 100073, China
| | - Mark C. Gillies
- Save Sight Institute, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW 2000, Australia; (S.Z.); (M.C.M.); (M.C.G.); (L.Z.)
| | - Ling Zhu
- Save Sight Institute, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW 2000, Australia; (S.Z.); (M.C.M.); (M.C.G.); (L.Z.)
| | - Ting Zhang
- Save Sight Institute, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW 2000, Australia; (S.Z.); (M.C.M.); (M.C.G.); (L.Z.)
- Correspondence: (M.Z.); (T.Z.)
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16
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Chang YH, Kang EYC, Liu PK, Levi SR, Wang HH, Tseng YJ, Seo GH, Lee H, Yeh LK, Chen KJ, Wu WC, Lai CC, Liu L, Wang NK. Photoreceptor Manifestations of Primary Mitochondrial Optic Nerve Disorders. Invest Ophthalmol Vis Sci 2022; 63:5. [PMID: 35506936 PMCID: PMC9078049 DOI: 10.1167/iovs.63.5.5] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Purpose To compare the manifestations of photoreceptors (PRs) in three hereditary optic neuropathies affected by primary mitochondrial dysfunction and discuss whether the retinal ganglion cells (RGCs) or the PRs are preferentially affected. Methods A retrospective analysis of patients with genetically confirmed diagnoses of optic neuropathies associated with mitochondrial dysfunction was performed. This cohort included Leber's hereditary optic neuropathy (LHON), autosomal dominant optic atrophy type 1 (OPA1), and optic atrophy type 13 (OPA13). Patient chart evaluations included clinical characteristics, best-corrected visual acuity (BCVA), fundus photography, spectral-domain optical coherence tomography (SD-OCT), electroretinogram (ERG), and visual evoked potential data. Results This analysis included seven patients with LHON, six with OPA1, and one with OPA13 from a tertiary medical center. Thirteen of the 14 individuals were male. The average BCVA at diagnosis was 20/285 and 20/500 in the right and left eyes, respectively. Five of the seven patients with LHON, and three of the six patients with OPA1 also showed a mild amplitude reduction or delayed latency on light-adapted ERG and 30-Hz flicker responses; however, SD-OCT imaging did not show correlated PR abnormalities. Notably, a 7-year follow-up of a patient with OPA13 revealed degeneration of RGCs prior to the degeneration of PRs. Follow-up data also demonstrated continuous loss of cone outer segment tips on SD-OCT imaging. Conclusions RGCs are, in general, affected by mitochondrial dysfunction, whereas variable PR dysfunction exists in patients with LHON and OPA1, especially with respect to the cone responses. Involvement of PRs is particularly evident in OPA13 after RGC degenerations.
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Affiliation(s)
- Yin-Hsi Chang
- Department of Ophthalmology, Chang Gung Memorial Hospital, Linkou Medical Center, Taoyuan, Taiwan.,College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Eugene Yu-Chuan Kang
- Department of Ophthalmology, Chang Gung Memorial Hospital, Linkou Medical Center, Taoyuan, Taiwan.,College of Medicine, Chang Gung University, Taoyuan, Taiwan.,Graduate Institute of Clinical Medical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Pei-Kang Liu
- Department of Ophthalmology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan.,School of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.,Institute of Biomedical Sciences, National Sun Yat-sen University, Kaohsiung, Taiwan.,Department of Ophthalmology, Edward S. Harkness Eye Institute, Columbia University Irving Medical Center, Columbia University, New York, New York, United States
| | - Sarah R Levi
- Department of Ophthalmology, Edward S. Harkness Eye Institute, Columbia University Irving Medical Center, Columbia University, New York, New York, United States
| | - Hung-Hsuan Wang
- Department of Ophthalmology, Edward S. Harkness Eye Institute, Columbia University Irving Medical Center, Columbia University, New York, New York, United States
| | - Yun-Ju Tseng
- Department of Ophthalmology, Edward S. Harkness Eye Institute, Columbia University Irving Medical Center, Columbia University, New York, New York, United States
| | - Go Hun Seo
- Division of Medical Genetics, 3billion, Inc., Seoul, South Korea
| | - Hane Lee
- Division of Medical Genetics, 3billion, Inc., Seoul, South Korea
| | - Lung-Kun Yeh
- Department of Ophthalmology, Chang Gung Memorial Hospital, Linkou Medical Center, Taoyuan, Taiwan.,College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Kuan-Jen Chen
- Department of Ophthalmology, Chang Gung Memorial Hospital, Linkou Medical Center, Taoyuan, Taiwan.,College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Wei-Chi Wu
- Department of Ophthalmology, Chang Gung Memorial Hospital, Linkou Medical Center, Taoyuan, Taiwan.,College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Chi-Chun Lai
- Department of Ophthalmology, Chang Gung Memorial Hospital, Linkou Medical Center, Taoyuan, Taiwan.,College of Medicine, Chang Gung University, Taoyuan, Taiwan.,Department of Ophthalmology, Chang Gung Memorial Hospital, Keelung, Taiwan
| | - Laura Liu
- Department of Ophthalmology, Chang Gung Memorial Hospital, Linkou Medical Center, Taoyuan, Taiwan.,School of Traditional Chinese Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Nan-Kai Wang
- Department of Ophthalmology, Edward S. Harkness Eye Institute, Columbia University Irving Medical Center, Columbia University, New York, New York, United States
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17
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Zouache MA. Variability in Retinal Neuron Populations and Associated Variations in Mass Transport Systems of the Retina in Health and Aging. Front Aging Neurosci 2022; 14:778404. [PMID: 35283756 PMCID: PMC8914054 DOI: 10.3389/fnagi.2022.778404] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Accepted: 01/13/2022] [Indexed: 11/17/2022] Open
Abstract
Aging is associated with a broad range of visual impairments that can have dramatic consequences on the quality of life of those impacted. These changes are driven by a complex series of alterations affecting interactions between multiple cellular and extracellular elements. The resilience of many of these interactions may be key to minimal loss of visual function in aging; yet many of them remain poorly understood. In this review, we focus on the relation between retinal neurons and their respective mass transport systems. These metabolite delivery systems include the retinal vasculature, which lies within the inner portion of the retina, and the choroidal vasculature located externally to the retinal tissue. A framework for investigation is proposed and applied to identify the structures and processes determining retinal mass transport at the cellular and tissue levels. Spatial variability in the structure of the retina and changes observed in aging are then harnessed to explore the relation between variations in neuron populations and those seen among retinal metabolite delivery systems. Existing data demonstrate that the relation between inner retinal neurons and their mass transport systems is different in nature from that observed between the outer retina and choroid. The most prominent structural changes observed across the eye and in aging are seen in Bruch’s membrane, which forms a selective barrier to mass transfers at the interface between the choroidal vasculature and the outer retina.
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18
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Zeviani M, Carelli V. Mitochondrial Retinopathies. Int J Mol Sci 2021; 23:210. [PMID: 35008635 PMCID: PMC8745158 DOI: 10.3390/ijms23010210] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 12/14/2021] [Accepted: 12/18/2021] [Indexed: 12/13/2022] Open
Abstract
The retina is an exquisite target for defects of oxidative phosphorylation (OXPHOS) associated with mitochondrial impairment. Retinal involvement occurs in two ways, retinal dystrophy (retinitis pigmentosa) and subacute or chronic optic atrophy, which are the most common clinical entities. Both can present as isolated or virtually exclusive conditions, or as part of more complex, frequently multisystem syndromes. In most cases, mutations of mtDNA have been found in association with mitochondrial retinopathy. The main genetic abnormalities of mtDNA include mutations associated with neurogenic muscle weakness, ataxia and retinitis pigmentosa (NARP) sometimes with earlier onset and increased severity (maternally inherited Leigh syndrome, MILS), single large-scale deletions determining Kearns-Sayre syndrome (KSS, of which retinal dystrophy is a cardinal symptom), and mutations, particularly in mtDNA-encoded ND genes, associated with Leber hereditary optic neuropathy (LHON). However, mutations in nuclear genes can also cause mitochondrial retinopathy, including autosomal recessive phenocopies of LHON, and slowly progressive optic atrophy caused by dominant or, more rarely, recessive, mutations in the fusion/mitochondrial shaping protein OPA1, encoded by a nuclear gene on chromosome 3q29.
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Affiliation(s)
- Massimo Zeviani
- Department of Neurosciences, The Clinical School, University of Padova, 35128 Padova, Italy
- Veneto Institute of Molecular Medicine, Via Orus 2, 35128 Padova, Italy
| | - Valerio Carelli
- Department of Biomedical and Neuromotor Sciences, University of Bologna, 40139 Bologna, Italy
- Programma di Neurogenetica, IRCCS Istituto delle Scienze Neurologiche di Bologna, Via Altura 6, 40139 Bologna, Italy
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19
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Jiang JW, Yi ZHZ, Wang XL, Liu JJ, Sun GP, Chen CZ. Quantitative analysis of retinal vasculature in normal eyes using ultra-widefield fluorescein angiography. Int J Ophthalmol 2021; 14:1915-1920. [PMID: 34926208 DOI: 10.18240/ijo.2021.12.16] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2021] [Accepted: 08/26/2021] [Indexed: 11/23/2022] Open
Abstract
AIM To quantify the area and density of retinal vascularity by ultra-widefield fluorescein angiography (UWFA). METHODS In a retrospective study, UWFA images were obtained using an ultra-widefield imaging device in 42 normal eyes of 42 patients. Central and peripheral steered images were used to define the edge of retinal vasculature by a certified grader. The length from the center of the optic disc to the edge of retinal vascularity (RVL) in each quadrant and the total retinal vascular perfusion area (RVPA) were determined by the grader using OptosAdvance software. The density of retinal vascularity (RVD) was quantified in different zones of central-steered images using Image J software. RESULTS Among 42 healthy eyes, the values for mean RVL in each quadrant were 19.007±0.781 mm (superior), 18.467±0.869 mm (inferior), 17.738±0.622 mm (nasal) and 24.241±1.336 mm (temporal). The mean RVPA was 1140.117±73.825 mm2. The mean RVD of the total retina was 4.850%±0.638%. RVD varied significantly between different retina zones (P<0.001), and significant differences existed in the RVD values for total retinal area in patients over 50 years old compared to those under 50 years old (P=0.033). No gender difference was found. CONCLUSION The UWFA device can be a promising tool for analyzing the overall retinal vasculature and may provide a better understanding of retinal vascular morphology in normal eyes. Aging may be related to lower RVD.
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Affiliation(s)
- Jing-Wen Jiang
- Eye Center, Renmin Hospital of Wuhan University, Wuhan 430060, Hubei Province, China
| | - Zuo-Hui-Zi Yi
- Eye Center, Renmin Hospital of Wuhan University, Wuhan 430060, Hubei Province, China
| | - Xiao-Ling Wang
- Eye Center, Renmin Hospital of Wuhan University, Wuhan 430060, Hubei Province, China
| | - Jue-Jun Liu
- Eye Center, Renmin Hospital of Wuhan University, Wuhan 430060, Hubei Province, China
| | - Gong-Peng Sun
- Eye Center, Renmin Hospital of Wuhan University, Wuhan 430060, Hubei Province, China
| | - Chang-Zheng Chen
- Eye Center, Renmin Hospital of Wuhan University, Wuhan 430060, Hubei Province, China
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20
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Özgümüs T, Sulaieva O, Jain R, Artner I, Lyssenko V. Starvation to Glucose Reprograms Development of Neurovascular Unit in Embryonic Retinal Cells. Front Cell Dev Biol 2021; 9:726852. [PMID: 34869314 PMCID: PMC8636675 DOI: 10.3389/fcell.2021.726852] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Accepted: 10/25/2021] [Indexed: 12/13/2022] Open
Abstract
Perinatal exposure to starvation is a risk factor for development of severe retinopathy in adult patients with diabetes. However, the underlying mechanisms are not completely understood. In the present study, we shed light on molecular consequences of exposure to short-time glucose starvation on the transcriptome profile of mouse embryonic retinal cells. We found a profound downregulation of genes regulating development of retinal neurons, which was accompanied by reduced expression of genes encoding for glycolytic enzymes and glutamatergic signaling. At the same time, glial and vascular markers were upregulated, mimicking the diabetes-associated increase of angiogenesis—a hallmark of pathogenic features in diabetic retinopathy. Energy deprivation as a consequence of starvation to glucose seems to be compensated by upregulation of genes involved in fatty acid elongation. Results from the present study demonstrate that short-term glucose deprivation during early fetal life differentially alters expression of metabolism- and function-related genes and could have detrimental and lasting effects on gene expression in the retinal neurons, glial cells, and vascular elements and thus potentially disrupting gene regulatory networks essential for the formation of the retinal neurovascular unit. Abnormal developmental programming during retinogenesis may serve as a trigger of reactive gliosis, accelerated neurodegeneration, and increased vascularization, which may promote development of severe retinopathy in patients with diabetes later in life.
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Affiliation(s)
- Türküler Özgümüs
- Department of Clinical Science, Center for Diabetes Research, University of Bergen, Bergen, Norway
| | | | - Ruchi Jain
- Department of Clinical Sciences, Lund University Diabetes Centre, Skåne University Hospital, Malmö, Sweden
| | - Isabella Artner
- Department of Clinical Sciences, Lund University Diabetes Centre, Skåne University Hospital, Malmö, Sweden
| | - Valeriya Lyssenko
- Department of Clinical Science, Center for Diabetes Research, University of Bergen, Bergen, Norway.,Department of Clinical Sciences, Lund University Diabetes Centre, Skåne University Hospital, Malmö, Sweden
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21
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Shivashankar G, Lim JC, Acosta ML. Glyceraldehyde-3-phosphate dehydrogenase and glutamine synthetase inhibition in the presence of pro-inflammatory cytokines contribute to the metabolic imbalance of diabetic retinopathy. Exp Eye Res 2021; 213:108845. [PMID: 34800480 DOI: 10.1016/j.exer.2021.108845] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 10/12/2021] [Accepted: 11/12/2021] [Indexed: 12/18/2022]
Abstract
Diabetic retinopathy (DR) is the leading cause of vision impairment in working age adults. In addition to hyperglycemia, retinal inflammation is an important driving factor for DR development. Although DR is clinically described as diabetes-induced damage to the retinal blood vessels, several studies have reported that metabolic dysregulation occurs in the retina prior to the development of microvascular damage. The two most commonly affected metabolic pathways in diabetic conditions are glycolysis and the glutamate pathway. We investigated the role of glyceraldehyde 3-phosphate dehydrogenase (GAPDH) and glutamine synthetase (GS) in an in-vitro model of DR incorporating high glucose and pro-inflammatory cytokines. We found that GAPDH and GS enzyme activity were not significantly affected in hyperglycemic conditions or after exposure to cytokines alone, but were significantly decreased in the DR model. This confirmed that pro-inflammatory cytokines IL-1β and TNFα enhance the hyperglycemic metabolic deficit. We further investigated metabolite and amino acid levels after specific pharmacological inhibition of GAPDH or GS in the absence/presence of pro-inflammatory cytokines. The results indicate that GAPDH inhibition increased glucose and addition of cytokines increased lactate and ATP levels and reduced glutamate levels. GS inhibition did not alter retinal metabolite levels but the addition of cytokines increased ATP levels and caused glutamate accumulation in Müller cells. We conclude that it is the action of pro-inflammatory cytokines concomitantly with the inhibition of the glycolytic or GS mediated glutamate recycling that contribute to metabolic dysregulation in DR. Therefore, in the absence of good glycemic control, therapeutic interventions aimed at regulating inflammation may prevent the onset of early metabolic imbalance in DR.
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Affiliation(s)
- Gaganashree Shivashankar
- School of Optometry and Vision Science and the New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand
| | - Julie C Lim
- Department of Physiology, School of Medical and Health Sciences and the New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand
| | - Monica L Acosta
- School of Optometry and Vision Science and the New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand.
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22
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Tomita Y, Usui-Ouchi A, Nilsson AK, Yang J, Ko M, Hellström A, Fu Z. Metabolism in Retinopathy of Prematurity. Life (Basel) 2021; 11:life11111119. [PMID: 34832995 PMCID: PMC8620873 DOI: 10.3390/life11111119] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Revised: 10/11/2021] [Accepted: 10/19/2021] [Indexed: 12/12/2022] Open
Abstract
Retinopathy of prematurity is defined as retinal abnormalities that occur during development as a consequence of disturbed oxygen conditions and nutrient supply after preterm birth. Both neuronal maturation and retinal vascularization are impaired, leading to the compensatory but uncontrolled retinal neovessel growth. Current therapeutic interventions target the hypoxia-induced neovessels but negatively impact retinal neurons and normal vessels. Emerging evidence suggests that metabolic disturbance is a significant and underexplored risk factor in the disease pathogenesis. Hyperglycemia and dyslipidemia correlate with the retinal neurovascular dysfunction in infants born prematurely. Nutritional and hormonal supplementation relieve metabolic stress and improve retinal maturation. Here we focus on the mechanisms through which metabolism is involved in preterm-birth-related retinal disorder from clinical and experimental investigations. We will review and discuss potential therapeutic targets through the restoration of metabolic responses to prevent disease development and progression.
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Affiliation(s)
- Yohei Tomita
- Department of Ophthalmology, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA; (Y.T.); (J.Y.); (M.K.)
| | - Ayumi Usui-Ouchi
- Department of Ophthalmology, Juntendo University Urayasu Hospital, Chiba 279-0021, Japan;
| | - Anders K. Nilsson
- Department of Clinical Neuroscience, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, 413 19 Gothenburg, Sweden; (A.K.N.); (A.H.)
| | - Jay Yang
- Department of Ophthalmology, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA; (Y.T.); (J.Y.); (M.K.)
| | - Minji Ko
- Department of Ophthalmology, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA; (Y.T.); (J.Y.); (M.K.)
| | - Ann Hellström
- Department of Clinical Neuroscience, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, 413 19 Gothenburg, Sweden; (A.K.N.); (A.H.)
| | - Zhongjie Fu
- Department of Ophthalmology, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA; (Y.T.); (J.Y.); (M.K.)
- Correspondence:
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23
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cGMP-PKG dependent transcriptome in normal and degenerating retinas: Novel insights into the retinitis pigmentosa pathology. Exp Eye Res 2021; 212:108752. [PMID: 34478738 DOI: 10.1016/j.exer.2021.108752] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Revised: 06/25/2021] [Accepted: 08/25/2021] [Indexed: 12/26/2022]
Abstract
Retinitis Pigmentosa represents a group of genetic disorders that cause progressive vision loss via degeneration of photoreceptors, but there is in principle no treatment available. For any therapy development, a deeper comprehension of the disease-leading mechanism(s) at the molecular level is needed. Here we focused on the cGMP-PKG system, which has been suggested to be a driver in several models of the disease. To gain insights in its downstream signaling we manipulated the cGMP-PKG system with the aid of organotypic retinal explant cultures from either a mouse-based disease model, i.e. the rd1 mouse, or its healthy wild-type counterpart (wt), by adding different types of cGMP analogues to either inhibit or activate PKG in retinal explants from rd1 and wt, respectively. An RNA sequencing was then performed to study the cGMP-PKG dependent transcriptome. Expression changes of gene sets related to specific pathways or functions, that fulfilled criteria involving that the changes should match PKG activation and inhibition, were determined via bioinformatics. The analyses highlighted that several gene sets linked to oxidative phosphorylation and mitochondrial pathways were regulated by this enzyme system. Specifically, the expression of such pathway components was upregulated in the rd1 treated with PKG inhibitor and downregulated in the wt with PKG activator treatment, suggesting that cGMP-PKG act as a negative regulator in this context. Downregulation of energy production pathways may thus play an integral part in the mechanism behind the degeneration for at least several RP mutations.
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24
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He J, Yamamoto M, Sumiyama K, Konagaya Y, Terai K, Matsuda M, Sato S. Two-photon AMPK and ATP imaging reveals the bias between rods and cones in glycolysis utility. FASEB J 2021; 35:e21880. [PMID: 34449091 DOI: 10.1096/fj.202101121r] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 08/08/2021] [Accepted: 08/11/2021] [Indexed: 12/15/2022]
Abstract
In vertebrates, retinal rod and cone photoreceptor cells rely significantly on glycolysis. Lactate released from photoreceptor cells fuels neighboring retinal pigment epithelium cells and Müller glial cells through oxidative phosphorylation. To understand this highly heterogeneous metabolic environment around photoreceptor cells, single-cell analysis is needed. Here, we visualized cellular AMP-activated protein kinase (AMPK) activity and ATP levels in the retina by two-photon microscopy. Transgenic mice expressing a hyBRET-AMPK biosensor were used for measuring the AMPK activity. GO-ATeam2 transgenic mice were used for measuring the ATP level. Temporal metabolic responses were successfully detected in the live retinal explants upon drug perfusion. A glycolysis inhibitor, 2-deoxy-d-glucose (2-DG), activated AMPK and reduced ATP. These effects were clearly stronger in rods than in cones. Notably, rod AMPK and ATP started to recover at 30 min from the onset of 2-DG perfusion. Consistent with these findings, ex vivo electroretinogram recordings showed a transient slowdown in rod dim flash responses during a 60-min 2-DG perfusion, whereas cone responses were not affected. Based on these results, we propose that cones surrounded by highly glycolytic rods become less dependent on glycolysis, and rods also become less dependent on glycolysis within 60 min upon the glycolysis inhibition.
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Affiliation(s)
- Jiazhou He
- Laboratory of Bioimaging and Cell Signaling, Graduate School of Biostudies, Kyoto University, Kyoto, Japan
| | - Masamichi Yamamoto
- Department of Research Promotion and Management, National Cerebral and Cardiovascular Center Research Institute, Osaka, Japan
| | - Kenta Sumiyama
- Laboratory for Mouse Genetic Engineering, RIKEN Center for Biosystems Dynamics Research, Osaka, Japan
| | - Yumi Konagaya
- Laboratory of Bioimaging and Cell Signaling, Graduate School of Biostudies, Kyoto University, Kyoto, Japan
| | - Kenta Terai
- Laboratory of Bioimaging and Cell Signaling, Graduate School of Biostudies, Kyoto University, Kyoto, Japan
| | - Michiyuki Matsuda
- Laboratory of Bioimaging and Cell Signaling, Graduate School of Biostudies, Kyoto University, Kyoto, Japan.,Department of Pathology and Biology of Diseases, Graduate School of Medicine, Kyoto University, Kyoto, Japan.,Institute for Integrated Cell-Material Sciences, Kyoto University, Kyoto, Japan
| | - Shinya Sato
- Laboratory of Bioimaging and Cell Signaling, Graduate School of Biostudies, Kyoto University, Kyoto, Japan
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25
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Min J, Zeng T, Roux M, Lazar D, Chen L, Tudzarova S. The Role of HIF1α-PFKFB3 Pathway in Diabetic Retinopathy. J Clin Endocrinol Metab 2021; 106:2505-2519. [PMID: 34019671 PMCID: PMC8372643 DOI: 10.1210/clinem/dgab362] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2021] [Indexed: 12/13/2022]
Abstract
Diabetic retinopathy (DR) is the leading cause of blindness for adults in developed countries. Both microvasculopathy and neurodegeneration are implicated in mechanisms of DR development, with neuronal impairment preceding microvascular abnormalities, which is often underappreciated in the clinic. Most current therapeutic strategies, including anti-vascular endothelial growth factor (anti-VEGF)-antibodies, aim at treating the advanced stages (diabetic macular edema and proliferative diabetic retinopathy) and fail to target the neuronal deterioration. Hence, new therapeutic approach(es) intended to address both vascular and neuronal impairment are urgently needed. The hypoxia-inducible factor 1α (HIF1α)-6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase 3 (PFKFB3) pathway is critically implicated in the islet pathology of diabetes. Recent evidence highlighted the pathway relevance for pathologic angiogenesis and neurodegeneration, two key aspects in DR. PFKFB3 is key to the sprouting angiogenesis, along with VEGF, by determining the endothelial tip-cell competition. Also, PFKFB3-driven glycolysis compromises the antioxidative capacity of neurons leading to neuronal loss and reactive gliosis. Therefore, the HIF1α-PFKFB3 signaling pathway is unique as being a pervasive pathological component across multiple cell types in the retina in the early as well as late stages of DR. A metabolic point-of-intervention based on HIF1α-PFKFB3 targeting thus deserves further consideration in DR.
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Affiliation(s)
- Jie Min
- Department of Endocrinology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
- Larry L. Hillblom Islet Research Center, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - Tianshu Zeng
- Department of Endocrinology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Margaretha Roux
- Groote Schuur and Red Cross Children’s Hospital, University of Cape Town, South Africa
| | - David Lazar
- Lazar Retina Ophthalmology, Los Angeles, CA, USA
| | - Lulu Chen
- Department of Endocrinology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
- Lulu Chen, PhD, Department of Endocrinology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1277 Jiefang Ave, Wuhan, Hubei, 430022, China.
| | - Slavica Tudzarova
- Larry L. Hillblom Islet Research Center, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
- Correspondence: Slavica Tudzarova, PhD, Larry Hillblom Islet Research Center, University of California Los Angeles, 10833 Le Conte Ave, CHS 33-165, Los Angeles, CA 90095, USA.
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26
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Mirra S, García-Arroyo R, B Domènech E, Gavaldà-Navarro A, Herrera-Úbeda C, Oliva C, Garcia-Fernàndez J, Artuch R, Villarroya F, Marfany G. CERKL, a retinal dystrophy gene, regulates mitochondrial function and dynamics in the mammalian retina. Neurobiol Dis 2021; 156:105405. [PMID: 34048907 DOI: 10.1016/j.nbd.2021.105405] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Revised: 05/06/2021] [Accepted: 05/21/2021] [Indexed: 11/30/2022] Open
Abstract
The retina is a highly active metabolic organ that displays a particular vulnerability to genetic and environmental factors causing stress and homeostatic imbalance. Mitochondria constitute a bioenergetic hub that coordinates stress response and cellular homeostasis, therefore structural and functional regulation of the mitochondrial dynamic network is essential for the mammalian retina. CERKL (ceramide kinase like) is a retinal degeneration gene whose mutations cause Retinitis Pigmentosa in humans, a visual disorder characterized by photoreceptors neurodegeneration and progressive vision loss. CERKL produces multiple isoforms with a dynamic subcellular localization. Here we show that a pool of CERKL isoforms localizes at mitochondria in mouse retinal ganglion cells. The depletion of CERKL levels in CerklKD/KO(knockdown/knockout) mouse retinas cause increase of autophagy, mitochondrial fragmentation, alteration of mitochondrial distribution, and dysfunction of mitochondrial-dependent bioenergetics and metabolism. Our results support CERKL as a regulator of autophagy and mitochondrial biology in the mammalian retina.
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Affiliation(s)
- Serena Mirra
- Department of Genetics, Microbiology and Statistics and Institute of Biomedicine (IBUB), Faculty of Biology, University of Barcelona, Barcelona, Spain; Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III, Barcelona, Spain; Institut de Biomedicina de la Universitat de Barcelona- Institut de Recerca Hospital Sant Joan de Déu, IBUB-IRSJD, Barcelona, Spain.
| | - Rocío García-Arroyo
- Department of Genetics, Microbiology and Statistics and Institute of Biomedicine (IBUB), Faculty of Biology, University of Barcelona, Barcelona, Spain
| | - Elena B Domènech
- Department of Genetics, Microbiology and Statistics and Institute of Biomedicine (IBUB), Faculty of Biology, University of Barcelona, Barcelona, Spain; Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III, Barcelona, Spain
| | - Aleix Gavaldà-Navarro
- Institut de Biomedicina de la Universitat de Barcelona- Institut de Recerca Hospital Sant Joan de Déu, IBUB-IRSJD, Barcelona, Spain; Department of Biochemistry and Molecular Biomedicine, Barcelona, Spain; CIBEROBN, Instituto de Salud Carlos III, Spain
| | - Carlos Herrera-Úbeda
- Department of Genetics, Microbiology and Statistics and Institute of Biomedicine (IBUB), Faculty of Biology, University of Barcelona, Barcelona, Spain
| | - Clara Oliva
- Clinical Biochemistry Department, Hospital Sant Joan de Déu, Spain
| | - Jordi Garcia-Fernàndez
- Department of Genetics, Microbiology and Statistics and Institute of Biomedicine (IBUB), Faculty of Biology, University of Barcelona, Barcelona, Spain
| | - Rafael Artuch
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III, Barcelona, Spain; Clinical Biochemistry Department, Hospital Sant Joan de Déu, Spain
| | - Francesc Villarroya
- Institut de Biomedicina de la Universitat de Barcelona- Institut de Recerca Hospital Sant Joan de Déu, IBUB-IRSJD, Barcelona, Spain; Department of Biochemistry and Molecular Biomedicine, Barcelona, Spain; CIBEROBN, Instituto de Salud Carlos III, Spain
| | - Gemma Marfany
- Department of Genetics, Microbiology and Statistics and Institute of Biomedicine (IBUB), Faculty of Biology, University of Barcelona, Barcelona, Spain; Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III, Barcelona, Spain; Institut de Biomedicina de la Universitat de Barcelona- Institut de Recerca Hospital Sant Joan de Déu, IBUB-IRSJD, Barcelona, Spain.
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27
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ADIPOR1 deficiency-induced suppression of retinal ELOVL2 and docosahexaenoic acid levels during photoreceptor degeneration and visual loss. Cell Death Dis 2021; 12:458. [PMID: 33963174 PMCID: PMC8105316 DOI: 10.1038/s41419-021-03741-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 03/23/2021] [Accepted: 03/25/2021] [Indexed: 02/03/2023]
Abstract
Lipid metabolism-related gene mutations can cause retinitis pigmentosa, a currently untreatable blinding disease resulting from progressive neurodegeneration of the retina. Here, we demonstrated the influence of adiponectin receptor 1 (ADIPOR1) deficiency in retinal neurodegeneration using Adipor1 knockout (KO) mice. Adipor1 mRNA was observed to be expressed in photoreceptors, predominately within the photoreceptor inner segment (PIS), and increased after birth during the development of the photoreceptor outer segments (POSs) where photons are received by the visual pigment, rhodopsin. At 3 weeks of age, visual function impairment, specifically photoreceptor dysfunction, as recorded by electroretinography (ERG), was evident in homozygous, but not heterozygous, Adipor1 KO mice. However, although photoreceptor loss was evident at 3 weeks of age and progressed until 10 weeks, the level of visual dysfunction was already substantial by 3 weeks, after which it was retained until 10 weeks of age. The rhodopsin mRNA levels had already decreased at 3 weeks, suggesting that reduced rhodopsin may have contributed to early visual loss. Moreover, inflammation and oxidative stress were induced in homozygous KO retinas. Prior to observation of photoreceptor loss via optical microscopy, electron microscopy revealed that POSs were present; however, they were misaligned and their lipid composition, including docosahexaenoic acid (DHA), which is critical in forming POSs, was impaired in the retina. Importantly, the expression of Elovl2, an elongase of very long chain fatty acids expressed in the PIS, was significantly reduced, and lipogenic genes, which are induced under conditions of reduced endogenous DHA synthesis, were increased in homozygous KO mice. The causal relationship between ADIPOR1 deficiency and Elovl2 repression, together with upregulation of lipogenic genes, was confirmed in vitro. Therefore, ADIPOR1 in the retina appears to be indispensable for ELOVL2 induction, which is likely required to supply sufficient DHA for appropriate photoreceptor function and survival.
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28
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Viegas FO, Neuhauss SCF. A Metabolic Landscape for Maintaining Retina Integrity and Function. Front Mol Neurosci 2021; 14:656000. [PMID: 33935647 PMCID: PMC8081888 DOI: 10.3389/fnmol.2021.656000] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Accepted: 03/22/2021] [Indexed: 01/27/2023] Open
Abstract
Neurons have high metabolic demands that are almost exclusively met by glucose supplied from the bloodstream. Glucose is utilized in complex metabolic interactions between neurons and glia cells, described by the astrocyte-neuron lactate shuttle (ANLS) hypothesis. The neural retina faces similar energy demands to the rest of the brain, with additional high anabolic needs to support continuous renewal of photoreceptor outer segments. This demand is met by a fascinating variation of the ANLS in which photoreceptors are the central part of a metabolic landscape, using glucose and supplying surrounding cells with metabolic intermediates. In this review we summarize recent evidence on how neurons, in particular photoreceptors, meet their energy and biosynthetic requirements by comprising a metabolic landscape of interdependent cells.
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Affiliation(s)
- Filipe O Viegas
- Department of Molecular Life Sciences, University of Zurich, Zurich, Switzerland.,Life Science Zurich Graduate School, Ph.D. Program in Molecular Life Sciences, Zurich, Switzerland
| | - Stephan C F Neuhauss
- Department of Molecular Life Sciences, University of Zurich, Zurich, Switzerland
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29
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Wang Z, Ji S, Huang Y, Liao K, Cui Z, Chu F, Chen J, Tang S. The daily gene transcription cycle in mouse retina. Exp Eye Res 2021; 207:108565. [PMID: 33838143 DOI: 10.1016/j.exer.2021.108565] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 03/23/2021] [Accepted: 03/30/2021] [Indexed: 12/13/2022]
Abstract
Many physiological retinal processes, such as outer segment disk shedding and visual sensitivity, exhibit a daily rhythm. However, the detailed transcriptome dynamics and related biological processes of the retina are not fully understood. Retinal tissues were collected from C57BL/6J male mice housed in a 12h light/12h dark (LD) cycle for 4 weeks, at Zeitgeber time (ZT) 0, 4, 8, 12, 16, and 20. Total RNA was extracted from the tissues and used for unique identifier RNA sequencing experiments. The rhythmicity of gene expression was determined using the MetaCycle R package. We found that 1741 genes (10.26%) were rhythmically expressed in the retina. According to the expression patterns, the rhythmically expressed genes were assigned to four clusters, each with about 361-492 genes, using the Mfuzz R package. The Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) analyses were conducted to identify pathways and biological processes of the profiled genes. Genes in Clusters 1 and 4 were associated with glycolysis and energy production, showed higher activity at night (from ZT16 to ZT20), and were enriched in the Hif-1α signaling pathway and low-oxygen-related terms. Genes in Cluster 2 were predominantly involved in cilium assembly and organization and were relatively upregulated during the day. Genes in Cluster 3 were associated with ribosome biosynthesis and were highly expressed during the day-night transition period. Taken together, these results demonstrate that a large proportion of retinal genes are expressed rhythmically. Genes involved in energy production and glycolysis are highly expressed at night, leading to relative hypoxia and activation of the Hif-1α signaling pathway. Genes associated with the formation of photoreceptor cilia are expressed during the day.
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Affiliation(s)
- Zhijie Wang
- Aier School of Ophthalmology, Central South University, Changsha, China; Aier Eye Institute, Changsha, China
| | | | - Yinhua Huang
- Aier School of Ophthalmology, Central South University, Changsha, China; Aier Eye Institute, Changsha, China
| | - Kai Liao
- Aier School of Ophthalmology, Central South University, Changsha, China; Aier Eye Institute, Changsha, China
| | | | - Feixue Chu
- Hangzhou Xihu Zhijiang Eye Hospital, China
| | - Jiansu Chen
- Aier School of Ophthalmology, Central South University, Changsha, China; Aier Eye Institute, Changsha, China; Key Laboratory for Regenerative Medicine, Ministry of Education, Jinan University, Guangzhou, China; Institute of Ophthalmology, Medical College, Jinan University, Guangzhou, China.
| | - Shibo Tang
- Aier School of Ophthalmology, Central South University, Changsha, China; Aier Eye Institute, Changsha, China; CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China.
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30
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Liu H, Prokosch V. Energy Metabolism in the Inner Retina in Health and Glaucoma. Int J Mol Sci 2021; 22:ijms22073689. [PMID: 33916246 PMCID: PMC8036449 DOI: 10.3390/ijms22073689] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 03/22/2021] [Accepted: 03/29/2021] [Indexed: 02/07/2023] Open
Abstract
Glaucoma, the leading cause of irreversible blindness, is a heterogeneous group of diseases characterized by progressive loss of retinal ganglion cells (RGCs) and their axons and leads to visual loss and blindness. Risk factors for the onset and progression of glaucoma include systemic and ocular factors such as older age, lower ocular perfusion pressure, and intraocular pressure (IOP). Early signs of RGC damage comprise impairment of axonal transport, downregulation of specific genes and metabolic changes. The brain is often cited to be the highest energy-demanding tissue of the human body. The retina is estimated to have equally high demands. RGCs are particularly active in metabolism and vulnerable to energy insufficiency. Understanding the energy metabolism of the inner retina, especially of the RGCs, is pivotal for understanding glaucoma’s pathophysiology. Here we review the key contributors to the high energy demands in the retina and the distinguishing features of energy metabolism of the inner retina. The major features of glaucoma include progressive cell death of retinal ganglions and optic nerve damage. Therefore, this review focuses on the energetic budget of the retinal ganglion cells, optic nerve and the relevant cells that surround them.
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31
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Jaroszynska N, Harding P, Moosajee M. Metabolism in the Zebrafish Retina. J Dev Biol 2021; 9:10. [PMID: 33804189 PMCID: PMC8006245 DOI: 10.3390/jdb9010010] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 03/08/2021] [Accepted: 03/11/2021] [Indexed: 12/12/2022] Open
Abstract
Retinal photoreceptors are amongst the most metabolically active cells in the body, consuming more glucose as a metabolic substrate than even the brain. This ensures that there is sufficient energy to establish and maintain photoreceptor functions during and after their differentiation. Such high dependence on glucose metabolism is conserved across vertebrates, including zebrafish from early larval through to adult retinal stages. As the zebrafish retina develops rapidly, reaching an adult-like structure by 72 hours post fertilisation, zebrafish larvae can be used to study metabolism not only during retinogenesis, but also in functionally mature retinae. The interplay between rod and cone photoreceptors and the neighbouring retinal pigment epithelium (RPE) cells establishes a metabolic ecosystem that provides essential control of their individual functions, overall maintaining healthy vision. The RPE facilitates efficient supply of glucose from the choroidal vasculature to the photoreceptors, which produce metabolic products that in turn fuel RPE metabolism. Many inherited retinal diseases (IRDs) result in photoreceptor degeneration, either directly arising from photoreceptor-specific mutations or secondary to RPE loss, leading to sight loss. Evidence from a number of vertebrate studies suggests that the imbalance of the metabolic ecosystem in the outer retina contributes to metabolic failure and disease pathogenesis. The use of larval zebrafish mutants with disease-specific mutations that mirror those seen in human patients allows us to uncover mechanisms of such dysregulation and disease pathology with progression from embryonic to adult stages, as well as providing a means of testing novel therapeutic approaches.
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Affiliation(s)
| | - Philippa Harding
- Institute of Ophthalmology, University College London, London EC1V 9EL, UK;
| | - Mariya Moosajee
- Institute of Ophthalmology, University College London, London EC1V 9EL, UK;
- Moorfields Eye Hospital NHS Foundation Trust, London EC1V 2PD, UK
- Great Ormond Street Hospital for Children NHS Foundation Trust, London WC1N 3JH, UK
- The Francis Crick Institute, London NW1 1AT, UK
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32
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Murenu E, Kostidis S, Lahiri S, Geserich AS, Imhof A, Giera M, Michalakis S. Metabolic Analysis of Vitreous/Lens and Retina in Wild Type and Retinal Degeneration Mice. Int J Mol Sci 2021; 22:ijms22052345. [PMID: 33652907 PMCID: PMC7956175 DOI: 10.3390/ijms22052345] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 02/19/2021] [Accepted: 02/23/2021] [Indexed: 02/06/2023] Open
Abstract
Photoreceptors are the light-sensing cells of the retina and the major cell type affected in most inherited retinal degenerations. Different metabolic pathways sustain their high energetic demand in physiological conditions, particularly aerobic glycolysis. The principal metabolome of the mature retina has been studied, but only limited information is available on metabolic adaptations in response to key developmental events, such as eye opening. Moreover, dynamic metabolic changes due to retinal degeneration are not well understood. Here, we aimed to explore and map the ocular metabolic dynamics induced by eye opening in healthy (wild type) or Pde6b-mutant (retinal degeneration 1, Rd1) mice, in which photoreceptors degenerate shortly after eye opening. To unravel metabolic differences emerging before and after eye opening under physiological and pathophysiological conditions, we performed nuclear magnetic resonance (NMR) spectroscopy-based metabolome analysis of wild type and Rd1 retina and vitreous/lens. We show that eye opening is accompanied by changes in the concentration of selected metabolites in the retina and by alterations in the vitreous/lens composition only in the retinal degeneration context. As such, we identify NAcetylaspartate as a potential novel vitreous/lens marker reflecting progressive retinal degeneration. Thus, our data can help elucidating mechanisms underlying key events in retinal physiology and reveal changes occurring in pathology, while highlighting the importance of the vitreous/lens in the characterization of retinal diseases.
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Affiliation(s)
- Elisa Murenu
- Department of Ophthalmology, Ludwig-Maximilians-Universität München, Mathildenstraße 8, 80336 Munich, Germany;
- Department of Pharmacy, Ludwig-Maximilians Universität München, Butenandtstr. 7, 81377 Munich, Germany;
| | - Sarantos Kostidis
- Leiden University Medical Center, Center for Proteomics & Metabolomics, P.O. Box 9600, 2300 RC Leiden, The Netherlands; (S.K.); (M.G.)
| | - Shibojyoti Lahiri
- Biomedical Center Munich-Molecular Biology, Ludwig-Maximilians-Universität München, Großhaderner Strasse 9, 82152 Planegg-Martinsried, Germany; (S.L.); (A.I.)
| | - Anna S. Geserich
- Department of Pharmacy, Ludwig-Maximilians Universität München, Butenandtstr. 7, 81377 Munich, Germany;
| | - Axel Imhof
- Biomedical Center Munich-Molecular Biology, Ludwig-Maximilians-Universität München, Großhaderner Strasse 9, 82152 Planegg-Martinsried, Germany; (S.L.); (A.I.)
| | - Martin Giera
- Leiden University Medical Center, Center for Proteomics & Metabolomics, P.O. Box 9600, 2300 RC Leiden, The Netherlands; (S.K.); (M.G.)
| | - Stylianos Michalakis
- Department of Ophthalmology, Ludwig-Maximilians-Universität München, Mathildenstraße 8, 80336 Munich, Germany;
- Department of Pharmacy, Ludwig-Maximilians Universität München, Butenandtstr. 7, 81377 Munich, Germany;
- Correspondence: ; Tel.: +49-89-2180-77325
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Actis Dato V, Sánchez MC, Chiabrando GA. LRP1 mediates the IGF-1-induced GLUT1 expression on the cell surface and glucose uptake in Müller glial cells. Sci Rep 2021; 11:4742. [PMID: 33637845 PMCID: PMC7910306 DOI: 10.1038/s41598-021-84090-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Accepted: 02/10/2021] [Indexed: 11/09/2022] Open
Abstract
Insulin-like Growth Factor-1 (IGF-1) is involved in the normal development and survival of retinal cells. Low-density lipoprotein Receptor-related Protein-1 (LRP1) plays a key role on the regulation of several membrane proteins, such as the IGF-1 receptor (IGF-1R). In brain astrocytes, LRP1 interact with IGF-1R and the glucose transporter type 1 (GLUT1), regulating the glucose uptake in these cells. Although GLUT1 is expressed in retinal Müller Glial Cells (MGCs), its regulation is not clear yet. Here, we investigated whether IGF-1 modulates GLUT1 traffic to plasma membrane (PM) and glucose uptake, as well as the involvement of LRP1 in this process in the human Müller glial-derived cell line (MIO-M1). We found that IGF-1 produced GLUT1 translocation to the PM, in a time-dependent manner involving the intracellular signaling activation of MAPK/ERK and PI3K/Akt pathways, and generated a significant glucose uptake. Moreover, we found a molecular association between LRP1 and GLUT1, which was significantly reduced by IGF-1. Finally, cells treated with specific siRNA for LRP1 showed an impaired GLUT1 expression on PM and decreased glucose uptake induced by IGF-1. We conclude that IGF-1 regulates glucose homeostasis in MGCs involving the expression of LRP1.
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Affiliation(s)
- Virginia Actis Dato
- Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Haya de la Torre s/n, Ciudad Universitaria, 5000, Córdoba, Argentina.,Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Córdoba, Argentina
| | - María Cecilia Sánchez
- Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Haya de la Torre s/n, Ciudad Universitaria, 5000, Córdoba, Argentina.,Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Córdoba, Argentina
| | - Gustavo Alberto Chiabrando
- Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Haya de la Torre s/n, Ciudad Universitaria, 5000, Córdoba, Argentina. .,Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Córdoba, Argentina.
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34
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Fu Z, Kern TS, Hellström A, Smith LEH. Fatty acid oxidation and photoreceptor metabolic needs. J Lipid Res 2021; 62:100035. [PMID: 32094231 PMCID: PMC7905050 DOI: 10.1194/jlr.tr120000618] [Citation(s) in RCA: 50] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 02/14/2020] [Indexed: 01/31/2023] Open
Abstract
Photoreceptors have high energy demands and a high density of mitochondria that produce ATP through oxidative phosphorylation (OXPHOS) of fuel substrates. Although glucose is the major fuel for CNS brain neurons, in photoreceptors (also CNS), most glucose is not metabolized through OXPHOS but is instead metabolized into lactate by aerobic glycolysis. The major fuel sources for photoreceptor mitochondria remained unclear for almost six decades. Similar to other tissues (like heart and skeletal muscle) with high metabolic rates, photoreceptors were recently found to metabolize fatty acids (palmitate) through OXPHOS. Disruption of lipid entry into photoreceptors leads to extracellular lipid accumulation, suppressed glucose transporter expression, and a duel lipid/glucose fuel shortage. Modulation of lipid metabolism helps restore photoreceptor function. However, further elucidation of the types of lipids used as retinal energy sources, the metabolic interaction with other fuel pathways, as well as the cross-talk among retinal cells to provide energy to photoreceptors is not fully understood. In this review, we will focus on the current understanding of photoreceptor energy demand and sources, and potential future investigations of photoreceptor metabolism.
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Affiliation(s)
- Zhongjie Fu
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA; Manton Center for Orphan Disease, Boston Children's Hospital, Boston, MA, USA.
| | - Timothy S Kern
- Center for Translational Vision Research, Gavin Herbert Eye Institute, Irvine, CA, USA
| | - Ann Hellström
- Section for Ophthalmology, Department of Clinical Neuroscience, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Göteborg, Sweden
| | - Lois E H Smith
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA.
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35
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Striebel JF, Race B, Leung JM, Schwartz C, Chesebro B. Prion-induced photoreceptor degeneration begins with misfolded prion protein accumulation in cones at two distinct sites: cilia and ribbon synapses. Acta Neuropathol Commun 2021; 9:17. [PMID: 33509294 PMCID: PMC7845122 DOI: 10.1186/s40478-021-01120-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Accepted: 01/09/2021] [Indexed: 12/15/2022] Open
Abstract
Accumulation of misfolded host proteins is central to neuropathogenesis of numerous human brain diseases including prion and prion-like diseases. Neurons of retina are also affected by these diseases. Previously, our group and others found that prion-induced retinal damage to photoreceptor cells in mice and humans resembled pathology of human retinitis pigmentosa caused by mutations in retinal proteins. Here, using confocal, epifluorescent and electron microscopy we followed deposition of disease-associated prion protein (PrPSc) and its association with damage to critical retinal structures following intracerebral prion inoculation. The earliest time and place of retinal PrPSc deposition was 67 days post-inoculation (dpi) on the inner segment (IS) of cone photoreceptors. At 104 and 118 dpi, PrPSc was associated with the base of cilia and swollen cone inner segments, suggesting ciliopathy as a pathogenic mechanism. By 118 dpi, PrPSc was deposited in both rods and cones which showed rootlet damage in the IS, and photoreceptor cell death was indicated by thinning of the outer nuclear layer. In the outer plexiform layer (OPL) in uninfected mice, normal host PrP (PrPC) was mainly associated with cone bipolar cell processes, but in infected mice, at 118 dpi, PrPSc was detected on cone and rod bipolar cell dendrites extending into ribbon synapses. Loss of ribbon synapses in cone pedicles and rod spherules in the OPL was observed to precede destruction of most rods and cones over the next 2–3 weeks. However, bipolar cells and horizontal cells were less damaged, indicating high selectivity among neurons for injury by prions. PrPSc deposition in cone and rod inner segments and on the bipolar cell processes participating in ribbon synapses appear to be critical early events leading to damage and death of photoreceptors after prion infection. These mechanisms may also occur in human retinitis pigmentosa and prion-like diseases, such as AD.
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36
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Potential Effects of Nutraceuticals in Retinopathy of Prematurity. Life (Basel) 2021; 11:life11020079. [PMID: 33499180 PMCID: PMC7912639 DOI: 10.3390/life11020079] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 01/15/2021] [Accepted: 01/16/2021] [Indexed: 02/07/2023] Open
Abstract
Retinopathy of prematurity (ROP), the most common cause of childhood blindness, is a hypoxia-induced eye disease characterized by retinal neovascularization. In the normal retina, a well-organized vascular network provides oxygen and nutrients as energy sources to maintain a normal visual function; however, it is disrupted when pathological angiogenesis is induced in ROP patients. Under hypoxia, inadequate oxygen and energy supply lead to oxidative stress and stimulate neovasculature formation as well as affecting the function of photoreceptors. In order to meet the metabolic needs in the developing retina, protection against abnormal vascular formation is one way to manage ROP. Although current treatments provide beneficial effects in reducing the severity of ROP, these invasive therapies may also induce life-long consequences such as systemic structural and functional complications as well as neurodevelopment disruption in the developing infants. Nutritional supplements for the newborns are a novel concept for restoring energy supply by protecting the retinal vasculature and may lead to better ROP management. Nutraceuticals are provided in a non-invasive manner without the developmental side effects associated with current treatments. These nutraceuticals have been investigated through various in vitro and in vivo methods and are indicated to protect retinal vasculature. Here, we reviewed and discussed how the use of these nutraceuticals may be beneficial in ROP prevention and management.
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37
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Zhang ZY, Sun YJ, Song JY, Fan B, Li GY. Experimental models and examination methods of retinal detachment. Brain Res Bull 2021; 169:51-62. [PMID: 33434623 DOI: 10.1016/j.brainresbull.2021.01.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 12/11/2020] [Accepted: 01/04/2021] [Indexed: 12/19/2022]
Abstract
Retinal detachment refers to the separation of the retinal neuroepithelium and pigment epithelium, usually involving the death of photoreceptor cells. Severe detachment may lead to permanent visual impairment if not treated properly and promptly. According to the underlying causes, retinal detachment falls into one of three categories: exudative retinal detachment, traction detachment, and rhegmatogenous retinal detachment. Like many other diseases, it is difficult to study the pathophysiology of retinal detachment directly in humans, because the human retinal tissues are precious, scarce and non-regenerative; thus, establishing experimental models that better mimic the disease is necessary. In this review, we summarize the existing models of the three categories of retinal detachment both in vivo and in vitro, along with an overview of their examination methods and the major strengths and weaknesses of each model.
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Affiliation(s)
- Zi-Yuan Zhang
- Second Hosp Jilin Univ, Dept Ophthalmol, 218 Zi Qiang St, Changchun, 130041, PR China.
| | - Ying-Jian Sun
- Second Hosp Jilin Univ, Dept Ophthalmol, 218 Zi Qiang St, Changchun, 130041, PR China.
| | - Jing-Yao Song
- Second Hosp Shandong Univ, Dept Ophthalmol, 247 Bei Yuan St, Jinan, 250031, PR China.
| | - Bin Fan
- Second Hosp Jilin Univ, Dept Ophthalmol, 218 Zi Qiang St, Changchun, 130041, PR China.
| | - Guang-Yu Li
- Second Hosp Jilin Univ, Dept Ophthalmol, 218 Zi Qiang St, Changchun, 130041, PR China.
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Mitochondria: The Retina's Achilles' Heel in AMD. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1256:237-264. [PMID: 33848005 DOI: 10.1007/978-3-030-66014-7_10] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Strong experimental evidence from studies in human donor retinas and animal models supports the idea that the retinal pathology associated with age-related macular degeneration (AMD) involves mitochondrial dysfunction and consequent altered retinal metabolism. This chapter provides a brief overview of mitochondrial structure and function, summarizes evidence for mitochondrial defects in AMD, and highlights the potential ramifications of these defects on retinal health and function. Discussion of mitochondrial haplogroups and their association with AMD brings to light how mitochondrial genetics can influence disease outcome. As one of the most metabolically active tissues in the human body, there is strong evidence that disruption in key metabolic pathways contributes to AMD pathology. The section on retinal metabolism reviews cell-specific metabolic differences and how the metabolic interdependence of each retinal cell type creates a unique ecosystem that is disrupted in the diseased retina. The final discussion includes strategies for therapeutic interventions that target key mitochondrial pathways as a treatment for AMD.
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Villar PS, Vergara C, Bacigalupo J. Energy sources that fuel metabolic processes in protruding finger-like organelles. FEBS J 2020; 288:3799-3812. [PMID: 33142020 DOI: 10.1111/febs.15620] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Revised: 10/16/2020] [Accepted: 11/02/2020] [Indexed: 12/19/2022]
Abstract
Cells possess a variety of organelles with characteristic structure and subcellular localization intimately linked to their specific function. While most are intracellular and found in virtually all eukaryotic cells, there is a small group of organelles of elongated cylindrical shapes in highly specialized cells that protrude into the extracellular space, such as cilia, flagella, and microvilli. The ATP required by intracellular organelles is amply available in the cytosol, largely generated by mitochondria. However, such is not the case for cilia and flagella, whose slender structures cannot accommodate mitochondria. These organelles consume massive amounts of ATP to carry out high energy-demanding functions, such as sensory transduction or motility. ATP from the nearest mitochondria or other reactions within the cell body is severely limited by diffusion and generally insufficient to fuel the entire length of cilia and flagella. These organelles overcome this fuel restriction by local generation of ATP, using mechanisms that vary depending on the nutrients that are available in their particular external environment. Here, we review, with emphasis in mammals, the remarkable adaptations that cilia and flagella use to fuel their metabolic needs. Additionally, we discuss how a decrease in nutrients surrounding olfactory cilia might impair olfaction in COVID-19 patients.
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Affiliation(s)
- Pablo S Villar
- Department of Biology, University of Maryland, College Park, MD, USA
| | - Cecilia Vergara
- Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Juan Bacigalupo
- Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
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40
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Blasiak J, Pawlowska E, Sobczuk A, Szczepanska J, Kaarniranta K. The Aging Stress Response and Its Implication for AMD Pathogenesis. Int J Mol Sci 2020; 21:ijms21228840. [PMID: 33266495 PMCID: PMC7700335 DOI: 10.3390/ijms21228840] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 11/12/2020] [Accepted: 11/20/2020] [Indexed: 02/07/2023] Open
Abstract
Aging induces several stress response pathways to counterbalance detrimental changes associated with this process. These pathways include nutrient signaling, proteostasis, mitochondrial quality control and DNA damage response. At the cellular level, these pathways are controlled by evolutionarily conserved signaling molecules, such as 5’AMP-activated protein kinase (AMPK), mechanistic target of rapamycin (mTOR), insulin/insulin-like growth factor 1 (IGF-1) and sirtuins, including SIRT1. Peroxisome proliferation-activated receptor coactivator 1 alpha (PGC-1α), encoded by the PPARGC1A gene, playing an important role in antioxidant defense and mitochondrial biogenesis, may interact with these molecules influencing lifespan and general fitness. Perturbation in the aging stress response may lead to aging-related disorders, including age-related macular degeneration (AMD), the main reason for vision loss in the elderly. This is supported by studies showing an important role of disturbances in mitochondrial metabolism, DDR and autophagy in AMD pathogenesis. In addition, disturbed expression of PGC-1α was shown to associate with AMD. Therefore, the aging stress response may be critical for AMD pathogenesis, and further studies are needed to precisely determine mechanisms underlying its role in AMD. These studies can include research on retinal cells produced from pluripotent stem cells obtained from AMD donors with the mutations, either native or engineered, in the critical genes for the aging stress response, including AMPK, IGF1, MTOR, SIRT1 and PPARGC1A.
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Affiliation(s)
- Janusz Blasiak
- Department of Molecular Genetics, Faculty of Biology and Environmental Protection, University of Lodz, 90-236 Lodz, Poland
- Correspondence: ; Tel.: +48-426354334
| | - Elzbieta Pawlowska
- Department of Orthodontics, Medical University of Lodz, 92-216 Lodz, Poland;
| | - Anna Sobczuk
- Department of Gynaecology and Obstetrics, Medical University of Lodz, 93-338 Lodz, Poland;
| | - Joanna Szczepanska
- Department of Pediatric Dentistry, Medical University of Lodz, 92-216 Lodz, Poland;
| | - Kai Kaarniranta
- Department of Ophthalmology, University of Eastern Finland, 70211 Kuopio, Finland;
- Department of Ophthalmology, Kuopio University Hospital, 70211 Kuopio, Finland
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Li B, Zhang T, Liu W, Wang Y, Xu R, Zeng S, Zhang R, Zhu S, Gillies MC, Zhu L, Du J. Metabolic Features of Mouse and Human Retinas: Rods versus Cones, Macula versus Periphery, Retina versus RPE. iScience 2020; 23:101672. [PMID: 33196018 PMCID: PMC7644940 DOI: 10.1016/j.isci.2020.101672] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 09/21/2020] [Accepted: 10/08/2020] [Indexed: 02/07/2023] Open
Abstract
Photoreceptors, especially cones, which are enriched in the human macula, have high energy demands, making them vulnerable to metabolic stress. Metabolic dysfunction of photoreceptors and their supporting retinal pigment epithelium (RPE) is an important underlying cause of degenerative retinal diseases. However, how cones and the macula support their exorbitant metabolic demand and communicate with RPE is unclear. By profiling metabolite uptake and release and analyzing metabolic genes, we have found cone-rich retinas and human macula share specific metabolic features with upregulated pathways in pyruvate metabolism, mitochondrial TCA cycle, and lipid synthesis. Human neural retina and RPE have distinct but complementary metabolic features. Retinal metabolism centers on NADH production and neurotransmitter biosynthesis. The retina needs aspartate to sustain its aerobic glycolysis and mitochondrial metabolism. RPE metabolism is directed toward NADPH production and biosynthesis of acetyl-rich metabolites, serine, and others. RPE consumes multiple nutrients, including proline, to produce metabolites for the retina.
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Affiliation(s)
- Bo Li
- Departments of Ophthalmology and Biochemistry, West Virginia University, WVU Eye Institute, One Medical Center Dr, PO Box 9193, Morgantown, WV 26506, USA.,Department of Ophthalmology, Affiliated Hospital of Yangzhou University, Yangzhou University, Yangzhou, Jiangsu Province 225100, China
| | - Ting Zhang
- Save Sight Institute, Sydney Medical School, University of Sydney, Sydney, NSW 2000, Australia
| | - Wei Liu
- Department of Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, Bronx, NY 10461, USA.,Department of Genetics, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Yekai Wang
- Departments of Ophthalmology and Biochemistry, West Virginia University, WVU Eye Institute, One Medical Center Dr, PO Box 9193, Morgantown, WV 26506, USA
| | - Rong Xu
- Departments of Ophthalmology and Biochemistry, West Virginia University, WVU Eye Institute, One Medical Center Dr, PO Box 9193, Morgantown, WV 26506, USA
| | - Shaoxue Zeng
- Save Sight Institute, Sydney Medical School, University of Sydney, Sydney, NSW 2000, Australia
| | - Rui Zhang
- Save Sight Institute, Sydney Medical School, University of Sydney, Sydney, NSW 2000, Australia
| | - Siyan Zhu
- Departments of Ophthalmology and Biochemistry, West Virginia University, WVU Eye Institute, One Medical Center Dr, PO Box 9193, Morgantown, WV 26506, USA
| | - Mark C Gillies
- Save Sight Institute, Sydney Medical School, University of Sydney, Sydney, NSW 2000, Australia
| | - Ling Zhu
- Save Sight Institute, Sydney Medical School, University of Sydney, Sydney, NSW 2000, Australia
| | - Jianhai Du
- Departments of Ophthalmology and Biochemistry, West Virginia University, WVU Eye Institute, One Medical Center Dr, PO Box 9193, Morgantown, WV 26506, USA
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Abstract
Based on clinical findings, diabetic retinopathy (DR) has traditionally been defined as a retinal microvasculopathy. Retinal neuronal dysfunction is now recognized as an early event in the diabetic retina before development of overt DR. While detrimental effects of diabetes on the survival and function of inner retinal cells, such as retinal ganglion cells and amacrine cells, are widely recognized, evidence that photoreceptors in the outer retina undergo early alterations in diabetes has emerged more recently. We review data from preclinical and clinical studies demonstrating a conserved reduction of electrophysiological function in diabetic retinas, as well as evidence for photoreceptor loss. Complementing in vivo studies, we discuss the ex vivo electroretinography technique as a useful method to investigate photoreceptor function in isolated retinas from diabetic animal models. Finally, we consider the possibility that early photoreceptor pathology contributes to the progression of DR, and discuss possible mechanisms of photoreceptor damage in the diabetic retina, such as enhanced production of reactive oxygen species and other inflammatory factors whose detrimental effects may be augmented by phototransduction.
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43
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Van Hove I, De Groef L, Boeckx B, Modave E, Hu TT, Beets K, Etienne I, Van Bergen T, Lambrechts D, Moons L, Feyen JHM, Porcu M. Single-cell transcriptome analysis of the Akimba mouse retina reveals cell-type-specific insights into the pathobiology of diabetic retinopathy. Diabetologia 2020; 63:2235-2248. [PMID: 32734440 DOI: 10.1007/s00125-020-05218-0] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Accepted: 05/08/2020] [Indexed: 12/12/2022]
Abstract
AIMS/HYPOTHESIS Diabetic retinopathy is a common complication of diabetes and a leading cause of visual impairment and blindness. Despite recent advances, our understanding of its pathophysiology remains incomplete. The aim of this study was to provide deeper insight into the complex network of molecular and cellular changes that underlie diabetic retinopathy by systematically mapping the transcriptional changes that occur in the different cellular compartments of the degenerating diabetic mouse retina. METHODS Single-cell RNA sequencing was performed on retinal tissue from 12-week-old wild-type and Akimba (Ins2Akita×Vegfa+/-) mice, which are known to replicate features of clinical diabetic retinopathy. This resulted in transcriptome data for 9474 retinal cells, which could be annotated to eight distinct retinal cell types. Using STRING analysis, we studied differentially expressed gene networks in neuronal, glial and immune cell compartments to create a comprehensive view on the pathological changes that occur in the Akimba retina. Using subclustering analysis, we further characterised macroglial and inflammatory cell subpopulations. Prominent findings were confirmed at the protein level using immunohistochemistry, western blotting and ELISA. RESULTS At 12 weeks, the Akimba retina was found to display degeneration of rod photoreceptors and presence of inflammatory cells, identified by subclustering analysis as monocyte, macrophage and microglial populations. Analysis of differentially expressed genes in the rod, cone, bipolar cell and macroglial compartments indicated changes in cell metabolism and ribosomal gene expression, gliosis, activation of immune system pathways and redox and metal ion dyshomeostasis. Experiments at the protein level supported a metabolic shift from glycolysis to oxidative phosphorylation (glyceraldehyde 3-phosphate dehydrogenase), activation of microglia/macrophages (isolectin-B4), metal ion and oxidative stress response (metallothionein and haem oxygenase-1) and reactive macroglia (glial fibrillary acidic protein and S100) in the Akimba retina, compared with wild-type mice. Our single-cell approach also indicates macroglial subpopulations with distinct fibrotic, inflammatory and gliotic profiles. CONCLUSIONS/INTERPRETATION Our study identifies molecular pathways underlying inflammatory, metabolic and oxidative stress-mediated changes in the Akimba mouse model of diabetic retinopathy and distinguishes distinct functional subtypes of inflammatory and macroglial cells. DATA AVAILABILITY RNA-seq data have been deposited in the ArrayExpress database at EMBL-EBI ( www.ebi.ac.uk/arrayexpress ) under accession number E-MTAB-9061. Graphical abstract.
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Affiliation(s)
- Inge Van Hove
- Oxurion NV, Gaston Geenslaan 1, B-3001, Leuven, Belgium
| | - Lies De Groef
- Neural Circuit Development and Regeneration Research Group, Department of Biology, KU Leuven, Naamsestraat 61, B-3000, Leuven, Belgium
| | - Bram Boeckx
- VIB Center for Cancer Biology, B-3000, Leuven, Belgium
- Laboratory of Translational Genetics, Department of Human Genetics, KU Leuven, Leuven, Belgium
| | - Elodie Modave
- VIB Center for Cancer Biology, B-3000, Leuven, Belgium
- Laboratory of Translational Genetics, Department of Human Genetics, KU Leuven, Leuven, Belgium
| | | | - Karen Beets
- Oxurion NV, Gaston Geenslaan 1, B-3001, Leuven, Belgium
| | | | | | - Diether Lambrechts
- VIB Center for Cancer Biology, B-3000, Leuven, Belgium
- Laboratory of Translational Genetics, Department of Human Genetics, KU Leuven, Leuven, Belgium
| | - Lieve Moons
- Neural Circuit Development and Regeneration Research Group, Department of Biology, KU Leuven, Naamsestraat 61, B-3000, Leuven, Belgium
| | | | - Michaël Porcu
- Oxurion NV, Gaston Geenslaan 1, B-3001, Leuven, Belgium.
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44
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Karlen SJ, Miller EB, Burns ME. Microglia Activation and Inflammation During the Death of Mammalian Photoreceptors. Annu Rev Vis Sci 2020; 6:149-169. [PMID: 32936734 PMCID: PMC10135402 DOI: 10.1146/annurev-vision-121219-081730] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Photoreceptors are highly specialized sensory neurons with unique metabolic and physiological requirements. These requirements are partially met by Müller glia and cells of the retinal pigment epithelium (RPE), which provide essential metabolites, phagocytose waste, and control the composition of the surrounding microenvironment. A third vital supporting cell type, the retinal microglia, can provide photoreceptors with neurotrophic support or exacerbate neuroinflammation and hasten neuronal cell death. Understanding the physiological requirements for photoreceptor homeostasis and the factors that drive microglia to best promote photoreceptor survival has important implications for the treatment and prevention of blinding degenerative diseases like retinitis pigmentosa and age-related macular degeneration.
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Affiliation(s)
- Sarah J. Karlen
- Department of Cell Biology and Human Anatomy, University of California, Davis, Davis, California 95616, USA
| | - Eric B. Miller
- Center for Neuroscience, University of California, Davis, Davis, California 95616, USA
| | - Marie E. Burns
- Department of Cell Biology and Human Anatomy, University of California, Davis, Davis, California 95616, USA
- Center for Neuroscience, University of California, Davis, Davis, California 95616, USA
- Department of Ophthalmology & Vision Science, University of California, Davis, Davis, California 95616, USA
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45
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Sundaramurthi H, Roche SL, Grice GL, Moran A, Dillion ET, Campiani G, Nathan JA, Kennedy BN. Selective Histone Deacetylase 6 Inhibitors Restore Cone Photoreceptor Vision or Outer Segment Morphology in Zebrafish and Mouse Models of Retinal Blindness. Front Cell Dev Biol 2020; 8:689. [PMID: 32984302 PMCID: PMC7479070 DOI: 10.3389/fcell.2020.00689] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Accepted: 07/07/2020] [Indexed: 12/19/2022] Open
Abstract
Blindness arising from retinal or macular degeneration results in significant social, health and economic burden. While approved treatments exist for neovascular (‘wet’) age-related macular degeneration, new therapeutic targets/interventions are needed for the more prevalent atrophic (‘dry’) form of age-related macular degeneration. Similarly, in inherited retinal diseases, most patients have no access to an effective treatment. Although macular and retinal degenerations are genetically and clinically distinct, common pathological hallmarks can include photoreceptor degeneration, retinal pigment epithelium atrophy, oxidative stress, hypoxia and defective autophagy. Here, we evaluated the potential of selective histone deacetylase 6 inhibitors to preserve retinal morphology or restore vision in zebrafish atp6v0e1–/– and mouse rd10 models. Histone deacetylase 6 inhibitor, tubastatin A-treated atp6v0e1–/– zebrafish show marked improvement in photoreceptor outer segment area (44.7%, p = 0.027) and significant improvement in vision (8-fold, p ≤ 0.0001). Tubastatin A-treated rd10/rd10 retinal explants show a significantly (p = 0.016) increased number of outer-segment labeled cone photoreceptors. In vitro, ATP6V0E1 regulated HIF-1α activity, but significant regulation of HIF-1α by histone deacetylase 6 inhibition in the retina was not detected. Proteomic profiling identified ubiquitin-proteasome, phototransduction, metabolism and phagosome as pathways, whose altered expression correlated with histone deacetylase 6 inhibitor mediated restoration of vision.
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Affiliation(s)
- Husvinee Sundaramurthi
- UCD Conway Institute, University College Dublin, Dublin, Ireland.,UCD School of Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland.,Systems Biology Ireland, University College Dublin, Dublin, Ireland.,UCD School of Medicine, University College Dublin, Dublin, Ireland
| | - Sarah L Roche
- School of Biochemistry, University College Cork, Cork, Ireland
| | - Guinevere L Grice
- Cambridge Institute of Therapeutic Immunology & Infectious Disease, University of Cambridge, Cambridge, United Kingdom
| | - Ailis Moran
- UCD Conway Institute, University College Dublin, Dublin, Ireland.,UCD School of Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland
| | - Eugene T Dillion
- UCD School of Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland.,Mass Spectrometry Resource, UCD Conway Institute, University College Dublin, Dublin, Ireland
| | - Giuseppe Campiani
- Department of Biotechnology, Chemistry and Pharmacy, Department of Excellence, University of Siena, Siena, Italy
| | - James A Nathan
- Cambridge Institute of Therapeutic Immunology & Infectious Disease, University of Cambridge, Cambridge, United Kingdom
| | - Breandán N Kennedy
- UCD Conway Institute, University College Dublin, Dublin, Ireland.,UCD School of Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland
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Haydinger CD, Kittipassorn T, Peet DJ. Power to see-Drivers of aerobic glycolysis in the mammalian retina: A review. Clin Exp Ophthalmol 2020; 48:1057-1071. [PMID: 32710505 DOI: 10.1111/ceo.13833] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 07/03/2020] [Accepted: 07/20/2020] [Indexed: 12/17/2022]
Abstract
The mammalian retina converts most glucose to lactate rather than catabolizing it completely to carbon dioxide via oxidative phosphorylation, despite the availability of oxygen. This unusual metabolism is known as aerobic glycolysis or the Warburg effect. Molecules and pathways that drive aerobic glycolysis have been identified and thoroughly studied in the context of cancer but remain relatively poorly understood in the retina. Here, we review recent research on the molecular mechanisms that underly aerobic glycolysis in the retina, focusing on key glycolytic enzymes including hexokinase 2 (HK2), pyruvate kinase M2 (PKM2) and lactate dehydrogenase A (LDHA). We also discuss the potential involvement of cell signalling and transcriptional pathways including phosphoinositide 3-kinase (PI3K) signalling, fibroblast growth factor receptor (FGFR) signalling, and hypoxia-inducible factor 1 (HIF-1), which have been implicated in driving aerobic glycolysis in the context of cancer.
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Affiliation(s)
- Cameron D Haydinger
- School of Biological Sciences, University of Adelaide, Adelaide, South Australia, Australia
| | - Thaksaon Kittipassorn
- School of Biological Sciences, University of Adelaide, Adelaide, South Australia, Australia.,Department of Physiology, Faculty of Medicine Siriraj Hospital, Mahidol University, Mahidol, Thailand
| | - Daniel J Peet
- School of Biological Sciences, University of Adelaide, Adelaide, South Australia, Australia
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Becker S, Carroll LS, Vinberg F. Rod phototransduction and light signal transmission during type 2 diabetes. BMJ Open Diabetes Res Care 2020; 8:8/1/e001571. [PMID: 32784250 PMCID: PMC7418690 DOI: 10.1136/bmjdrc-2020-001571] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 06/22/2020] [Accepted: 07/02/2020] [Indexed: 01/31/2023] Open
Abstract
INTRODUCTION Diabetic retinopathy is a major complication of diabetes recently associated with compromised photoreceptor function. Multiple stressors in diabetes, such as hyperglycemia, oxidative stress and inflammatory factors, have been identified, but systemic effects of diabetes on outer retina function are incompletely understood. We assessed photoreceptor physiology in vivo and in isolated retinas to better understand how alterations in the cellular environment compared with intrinsic cellular/molecular properties of the photoreceptors, affect light signal transduction and transmission in the retina in chronic type 2 diabetes. RESEARCH DESIGN AND METHODS Photoreceptor function was assessed in BKS.Cs-Dock7m+/+Lepr db/J mice, using homozygotes for Leprdb as a model of type 2 diabetes and heterozygotes as non-diabetic controls. In vivo electroretinogram (ERG) was recorded in dark-adapted mice at both 3 and 6 months of age. For ex vivo ERG, isolated retinas were superfused with oxygenated Ames' media supplemented with 30 mM glucose or mannitol as iso-osmotic control and electrical responses to light stimuli were recorded. RESULTS We found that both transduction and transmission of light signals by rod photoreceptors were compromised in 6-month-old (n=9-10 eyes from 5 animals, ***p<0.001) but not in 3-month-old diabetic mice in vivo (n=4-8 eyes from 2 to 4 animals). In contrast, rod signaling was similar in isolated retinas from 6-month-old control and diabetic mice under normoglycemic conditions (n=11). Acutely elevated glucose ex vivo increased light-evoked rod photoreceptor responses in control mice (n=11, ***p<0.001), but did not affect light responses in diabetic mice (n=11). CONCLUSIONS Our data suggest that long-term diabetes does not irreversibly change the ability of rod photoreceptors to transduce and mediate light signals. However, type 2 diabetes appears to induce adaptational changes in the rods that render them less sensitive to increased availability of glucose.
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Affiliation(s)
- Silke Becker
- Ophthalmology & Visual Sciences, John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, USA
| | - Lara S Carroll
- Ophthalmology & Visual Sciences, John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, USA
| | - Frans Vinberg
- Ophthalmology & Visual Sciences, John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, USA
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Metabolite therapy guided by liquid biopsy proteomics delays retinal neurodegeneration. EBioMedicine 2020; 52:102636. [PMID: 32028070 PMCID: PMC7005447 DOI: 10.1016/j.ebiom.2020.102636] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Revised: 12/26/2019] [Accepted: 01/09/2020] [Indexed: 02/06/2023] Open
Abstract
Background Neurodegenerative diseases are incurable disorders caused by progressive neuronal cell death. Retinitis pigmentosa (RP) is a blinding neurodegenerative disease that results in photoreceptor death and progresses to the loss of the entire retinal network. We previously found that proteomic analysis of the adjacent vitreous served as way to indirectly biopsy the retina and identify changes in the retinal proteome. Methods We analyzed protein expression in liquid vitreous biopsies from autosomal recessive (ar)RP patients with PDE6A mutations and arRP mice with Pde6ɑ mutations. Proteomic analysis of retina and vitreous samples identified molecular pathways affected at the onset of photoreceptor death. Based on affected molecular pathways, arRP mice were treated with a ketogenic diet or metabolites involved in fatty-acid synthesis, oxidative phosphorylation, and the tricarboxylic acid (TCA) cycle. Findings Dietary supplementation of a single metabolite, ɑ-ketoglutarate, increased docosahexaeonic acid levels, provided neuroprotection, and enhanced visual function in arRP mice. A ketogenic diet delayed photoreceptor cell loss, while vitamin B supplementation had a limited effect. Finally, desorption electrospray ionization mass spectrometry imaging (DESI-MSI) on ɑ-ketoglutarate-treated mice revealed restoration of metabolites that correlated with our proteomic findings: uridine, dihydrouridine, and thymidine (pyrimidine and purine metabolism), glutamine and glutamate (glutamine/glutamate conversion), and succinic and aconitic acid (TCA cycle). Interpretation This study demonstrates that replenishing TCA cycle metabolites via oral supplementation prolongs retinal function and provides a neuroprotective effect on the photoreceptor cells and inner retinal network. Funding NIH grants [R01EY026682, R01EY024665, R01EY025225, R01EY024698, R21AG050437, P30EY026877, 5P30EY019007, R01EY018213, F30EYE027986, T32GM007337, 5P30CA013696], NSF grant CHE-1734082.
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Espinheira Gomes F, Abou-Madi N, Ledbetter EC, McArt J. Spectral-domain optical coherence tomography imaging of normal foveae: A pilot study in 17 diurnal birds of prey. Vet Ophthalmol 2020; 23:347-357. [PMID: 31981286 DOI: 10.1111/vop.12732] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 11/25/2019] [Accepted: 11/29/2019] [Indexed: 11/29/2022]
Abstract
OBJECTIVE To describe and to establish normative data for the foveae of diurnal birds of prey using spectral-domain optical coherence tomography (SD-OCT). METHODS All animals (9 red-tailed hawks, 3 Cooper's hawks, 3 American kestrels, 1 sharp-shinned hawk, and 1 broad-winged hawk) had an ophthalmic examination performed with slit lamp biomicroscopy and indirect ophthalmoscopy. Following ophthalmic examination, SD-OCT was performed in each eye that had a visible fundus and normal fovea on SD-OCT. Temporal foveae depth, central foveae depth, pecten-temporal foveae distance, and pecten-central foveae distance (PCFD) were measured using SD-OCT. Differences in measured outcomes between species were determined using generalized linear mixed effects models. RESULTS The central foveae (mean ± SD) displayed a small but significant depth variation between species (P = .002) and was deepest in red-tailed hawks (293 ± 16 µm), followed by American kestrels (260 ± 12 µm), broad-winged hawks (256 ± 16 µm), Cooper's hawks (250 ± 9 µm), and sharp-shinned hawks (239 ± 16 µm). The temporal foveae were shallower than the central foveae in all species tested, and there was a significant variation between species (P < .001). The temporal foveae (mean ± SD) were deepest in American kestrels (137 ± 8 µm), followed by red-tailed hawks (129 ± 3 µm), broad-winged hawks (59.5 ± 3.5 µm), Cooper's hawks (20.3 ± 6.4 µm), and sharp-shinned hawks (17.5 ± 0.7 µm). Pecten-temporal foveae distance was approximately 30% shorter than PCFD in all species. There were no differences in the parameters tested between the eyes within each species (P ≥ .47). CONCLUSION Normative foveae SD-OCT data were obtained in four species of diurnal birds of prey. Further studies are warranted to provide structural and functional information regarding normal and pathologic changes that can affect the foveae.
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Affiliation(s)
| | - Noha Abou-Madi
- College of Veterinary Medicine, Cornell University, Ithaca, NY, USA
| | - Eric C Ledbetter
- College of Veterinary Medicine, Cornell University, Ithaca, NY, USA
| | - Jessica McArt
- College of Veterinary Medicine, Cornell University, Ithaca, NY, USA
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50
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Milićević N, ten Brink JB, ten Asbroek AL, Bergen AA, Felder-Schmittbuhl MP. The circadian clock regulates RPE-mediated lactate transport via SLC16A1 (MCT1). Exp Eye Res 2020; 190:107861. [DOI: 10.1016/j.exer.2019.107861] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2019] [Revised: 10/18/2019] [Accepted: 10/23/2019] [Indexed: 01/13/2023]
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