1
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Costa BLD, Quinn PMJ, Wu WH, Liu S, Nolan ND, Demirkol A, Tsai YT, Caruso SM, Cabral T, Wang NK, Tsang SH. Targeting miR-181a/b in retinitis pigmentosa: implications for disease progression and therapy. Cell Biosci 2024; 14:64. [PMID: 38773556 PMCID: PMC11110387 DOI: 10.1186/s13578-024-01243-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2024] [Accepted: 04/30/2024] [Indexed: 05/24/2024] Open
Abstract
BACKGROUND Retinitis pigmentosa (RP) is a genetically heterogeneous group of degenerative disorders causing progressive vision loss due to photoreceptor death. RP affects other retinal cells, including the retinal pigment epithelium (RPE). MicroRNAs (miRs) are implicated in RP pathogenesis, and downregulating miR-181a/b has shown therapeutic benefit in RP mouse models by improving mitochondrial function. This study investigates the expression profile of miR-181a/b in RPE cells and the neural retina during RP disease progression. We also evaluate how miR-181a/b downregulation, by knocking out miR-181a/b-1 cluster in RPE cells, confers therapeutic efficacy in an RP mouse model and explore the mechanisms underlying this process. RESULTS Our findings reveal distinct expression profiles, with downregulated miR-181a/b in RPE cells suggesting a protective response and upregulated miR-181a/b in the neural retina indicating a role in disease progression. We found that miR-181a/b-2, encoded in a separate genomic cluster, compensates for miR-181a/b-1 ablation in RPE cells at late time points. The transient downregulation of miR-181a/b in RPE cells at post-natal week 6 (PW6) led to improved RPE morphology, retarded photoreceptor degeneration and decreased RPE aerobic glycolysis. CONCLUSIONS Our study elucidates the underlying mechanisms associated with the therapeutic modulation of miR-181a/b, providing insights into the metabolic processes linked to its RPE-specific downregulation. Our data further highlights the impact of compensatory regulation between miR clusters with implications for the development of miR-based therapeutics.
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Affiliation(s)
- Bruna Lopes da Costa
- Jonas Children's Vision Care (JCVC) and Barbara & Donald Jonas Stem Cell Laboratory, New York-Presbyterian Hospital, New York, NY, USA
- Department of Biomedical Engineering, Columbia University, New York, NY, USA
| | - Peter M J Quinn
- Department of Ophthalmology, Columbia University Irving Medical Center, New York, NY, USA
| | - Wen-Hsuan Wu
- Jonas Children's Vision Care (JCVC) and Barbara & Donald Jonas Stem Cell Laboratory, New York-Presbyterian Hospital, New York, NY, USA
- Department of Ophthalmology, Columbia University Irving Medical Center, New York, NY, USA
| | - Siyuan Liu
- Jonas Children's Vision Care (JCVC) and Barbara & Donald Jonas Stem Cell Laboratory, New York-Presbyterian Hospital, New York, NY, USA
- Department of Biomedical Engineering, Columbia University, New York, NY, USA
| | - Nicholas D Nolan
- Jonas Children's Vision Care (JCVC) and Barbara & Donald Jonas Stem Cell Laboratory, New York-Presbyterian Hospital, New York, NY, USA
- Department of Biomedical Engineering, Columbia University, New York, NY, USA
| | - Aykut Demirkol
- Jonas Children's Vision Care (JCVC) and Barbara & Donald Jonas Stem Cell Laboratory, New York-Presbyterian Hospital, New York, NY, USA
- Department of Ophthalmology, Columbia University Irving Medical Center, New York, NY, USA
| | - Yi-Ting Tsai
- Jonas Children's Vision Care (JCVC) and Barbara & Donald Jonas Stem Cell Laboratory, New York-Presbyterian Hospital, New York, NY, USA
- Department of Biomedical Engineering, Columbia University, New York, NY, USA
| | - Salvatore Marco Caruso
- Jonas Children's Vision Care (JCVC) and Barbara & Donald Jonas Stem Cell Laboratory, New York-Presbyterian Hospital, New York, NY, USA
- Department of Biomedical Engineering, Columbia University, New York, NY, USA
| | - Thiago Cabral
- Department of Specialized Medicine, CCS and Vision Center Unit, Ophthalmology EBSERH, HUCAM/CCS, UFES-Federal University of Espírito Santo (UFES), Vitória, Brazil
- Department of Ophthalmology, Federal University of Sao Paulo (UNIFESP), São Paulo, Brazil
| | - Nan-Kai Wang
- Jonas Children's Vision Care (JCVC) and Barbara & Donald Jonas Stem Cell Laboratory, New York-Presbyterian Hospital, New York, NY, USA
- Department of Ophthalmology, Columbia University Irving Medical Center, New York, NY, USA
| | - Stephen H Tsang
- Jonas Children's Vision Care (JCVC) and Barbara & Donald Jonas Stem Cell Laboratory, New York-Presbyterian Hospital, New York, NY, USA.
- Department of Biomedical Engineering, Columbia University, New York, NY, USA.
- Department of Ophthalmology, Columbia University Irving Medical Center, New York, NY, USA.
- Department of Pathology & Cell Biology, Columbia University Irving Medical Center, New York, NY, USA.
- Columbia Stem Cell Initiative, Institute of Human Nutrition ,Vagelos College of Physicians and Surgeons, Columbia University Irving Medical Center, New York, NY, USA.
- Columbia University Irving Medical Center, Hammer Health Sciences Center 205b, 701 West 168th Street, New York, NY, 10032, USA.
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2
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Xue Y, Cepko CL. Gene Therapies for Retinitis Pigmentosa that Target Glucose Metabolism. Cold Spring Harb Perspect Med 2024; 14:a041289. [PMID: 37460158 PMCID: PMC11065158 DOI: 10.1101/cshperspect.a041289] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/04/2024]
Abstract
Retinitis pigmentosa is a blinding disease wherein rod photoreceptors are affected first, due to the expression of a disease gene, leading to the loss of dim light vision. In many cases, cones do not express the disease gene, yet they are also affected and eventually die, typically after most of the rods in their neighborhood have died. The cause of secondary cone death is unclear. Photoreceptors are one of the most energy-demanding cell types in the body and consume a high amount of glucose. At an early stage of degeneration, the cones appear to have a shortage of glucose to fuel their metabolism. This review focuses on gene therapy approaches that address this potential metabolic shortcoming.
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Affiliation(s)
- Yunlu Xue
- Lingang Laboratory, Shanghai 200031, China
| | - Constance L Cepko
- Departments of Genetics and Ophthalmology, Howard Hughes Medical Institute, Harvard Medical School, Boston, Massachusetts 02115, USA
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3
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Nolan ND, Cui X, Robbings BM, Demirkol A, Pandey K, Wu WH, Hu HF, Jenny LA, Lin CS, Hass DT, Du J, Hurley JB, Tsang SH. CRISPR editing of anti-anemia drug target rescues independent preclinical models of retinitis pigmentosa. Cell Rep Med 2024; 5:101459. [PMID: 38518771 PMCID: PMC11031380 DOI: 10.1016/j.xcrm.2024.101459] [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: 12/21/2023] [Accepted: 02/14/2024] [Indexed: 03/24/2024]
Abstract
Retinitis pigmentosa (RP) is one of the most common forms of hereditary neurodegeneration. It is caused by one or more of at least 3,100 mutations in over 80 genes that are primarily expressed in rod photoreceptors. In RP, the primary rod-death phase is followed by cone death, regardless of the underlying gene mutation that drove the initial rod degeneration. Dampening the oxidation of glycolytic end products in rod mitochondria enhances cone survival in divergent etiological disease models independent of the underlying rod-specific gene mutations. Therapeutic editing of the prolyl hydroxylase domain-containing protein gene (PHD2, also known as Egln1) in rod photoreceptors led to the sustained survival of both diseased rods and cones in both preclinical autosomal-recessive and dominant RP models. Adeno-associated virus-mediated CRISPR-based therapeutic reprogramming of the aerobic glycolysis node may serve as a gene-agnostic treatment for patients with various forms of RP.
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Affiliation(s)
- Nicholas D Nolan
- Jonas Children's Vision Care and Bernard & Shirlee Brown Glaucoma Laboratory, Institute of Human Nutrition, Columbia Stem Cell Initiative, New York, NY 10032, USA; Department of Biomedical Engineering, Columbia University, New York, NY 10027, USA; Edward S. Harkness Eye Institute, Columbia University Irving Medical Center, New York-Presbyterian Hospital, New York, NY 10032, USA
| | - Xuan Cui
- Jonas Children's Vision Care and Bernard & Shirlee Brown Glaucoma Laboratory, Institute of Human Nutrition, Columbia Stem Cell Initiative, New York, NY 10032, USA; Edward S. Harkness Eye Institute, Columbia University Irving Medical Center, New York-Presbyterian Hospital, New York, NY 10032, USA
| | - Brian M Robbings
- Department of Biochemistry, The University of Washington, Seattle, WA 98195, USA; Diabetes Institute, The University of Washington, Seattle, WA 98195, USA
| | - Aykut Demirkol
- Jonas Children's Vision Care and Bernard & Shirlee Brown Glaucoma Laboratory, Institute of Human Nutrition, Columbia Stem Cell Initiative, New York, NY 10032, USA; Edward S. Harkness Eye Institute, Columbia University Irving Medical Center, New York-Presbyterian Hospital, New York, NY 10032, USA; Vocational School of Health Services, Uskudar University, 34672 Istanbul, Turkey
| | - Kriti Pandey
- Department of Biochemistry, The University of Washington, Seattle, WA 98195, USA
| | - Wen-Hsuan Wu
- Jonas Children's Vision Care and Bernard & Shirlee Brown Glaucoma Laboratory, Institute of Human Nutrition, Columbia Stem Cell Initiative, New York, NY 10032, USA; Edward S. Harkness Eye Institute, Columbia University Irving Medical Center, New York-Presbyterian Hospital, New York, NY 10032, USA
| | - Hannah F Hu
- Jonas Children's Vision Care and Bernard & Shirlee Brown Glaucoma Laboratory, Institute of Human Nutrition, Columbia Stem Cell Initiative, New York, NY 10032, USA; Department of Biomedical Engineering, Columbia University, New York, NY 10027, USA; Edward S. Harkness Eye Institute, Columbia University Irving Medical Center, New York-Presbyterian Hospital, New York, NY 10032, USA
| | - Laura A Jenny
- Jonas Children's Vision Care and Bernard & Shirlee Brown Glaucoma Laboratory, Institute of Human Nutrition, Columbia Stem Cell Initiative, New York, NY 10032, USA; Edward S. Harkness Eye Institute, Columbia University Irving Medical Center, New York-Presbyterian Hospital, New York, NY 10032, USA
| | - Chyuan-Sheng Lin
- Herbert Irving Comprehensive Cancer Center, Department of Pathology & Cell Biology, Columbia University Irving Medical Center, New York, NY 10032, USA; Departments of Ophthalmology, Pathology & Cell Biology, Vagelos College of Physicians and Surgeons, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Daniel T Hass
- Department of Biochemistry, The University of Washington, Seattle, WA 98195, USA
| | - Jianhai Du
- Department of Ophthalmology and Visual Sciences, West Virginia University, Morgantown, WV 26506, USA; Department of Biochemistry and Molecular Medicine, West Virginia University, Morgantown, WV 26501, USA
| | - James B Hurley
- Department of Biochemistry, The University of Washington, Seattle, WA 98195, USA.
| | - Stephen H Tsang
- Jonas Children's Vision Care and Bernard & Shirlee Brown Glaucoma Laboratory, Institute of Human Nutrition, Columbia Stem Cell Initiative, New York, NY 10032, USA; Department of Biomedical Engineering, Columbia University, New York, NY 10027, USA; Edward S. Harkness Eye Institute, Columbia University Irving Medical Center, New York-Presbyterian Hospital, New York, NY 10032, USA; Departments of Ophthalmology, Pathology & Cell Biology, Vagelos College of Physicians and Surgeons, Columbia University Irving Medical Center, New York, NY 10032, USA.
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4
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Jia J, Tao W, Chen T, Zhong Q, Sun J, Xu Y, Sui X, Chen C, Zhang Z. SIRT6 Improves Hippocampal Neurogenesis Following Prolonged Sleep Deprivation Through Modulating Energy Metabolism in Developing rats. Mol Neurobiol 2024; 61:883-899. [PMID: 37668962 DOI: 10.1007/s12035-023-03585-4] [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: 05/19/2023] [Accepted: 08/14/2023] [Indexed: 09/06/2023]
Abstract
OBJECTIVE Prolonged sleep deprivation is known to have detrimental effects on the hippocampus during development or in adulthood. Furthermore, it is well-established that sleep deprivation disrupts energy metabolism broadly. SIRT6 is a critical regulator of energy metabolism in both central and peripheral tissues. This study aims to investigate the role of SIRT6 in modulating hippocampal neurogenesis following sleep deprivation during development, and elucidate the underlying mechanism. METHODS Male Sprague-Dawley rats, aged three weeks, were subjected to 2 weeks of sleep deprivation using the modified multiple platform method. Metabolomic profiling was carried out using the liquid chromatography-electrospray ionization-tandem mass spectrometry (LC‒ESI‒MS/MS). To investigate the role of SIRT6 in energy metabolism, the rats were administered with either the SIRT6-specific inhibitor, OSS128167, or SIRT6-overexpressing adeno-associated virus (AAV). Hippocampal neurogenesis was assessed by immunostaining with markers for neural stem cells (SOX2), immature neurons [doublecortin (DCX)] and newborn cells (BrdU). Sparse labeling of adult neurons was used to determine the density of dendritic spines in the dentate gyrus (DG). The Y-maze and novel object recognition (NOR) tests were performed to evaluate the spatial and recognition memory. SIRT6 expression was examined using immunofluorescence and western blotting (WB). The inhibition of SIRT6 was confirmed by assessing the acetylation of histone 3 lysine 9 (aceH3K9), a well-known substrate of SIRT6, through WB. RESULTS Sleep deprivation for a period of two weeks leads to inhibited hippocampal neurogenesis, reduced density of dendritic spines in the DG, and impaired memory, accompanied by decreased SIRT6 expression and disrupted energy metabolism. Similar to sleep deprivation, administration of OSS128167 significantly decreased energy metabolism, leading to reduced neurogenesis and memory dysfunction. Notably, the abnormal hippocampal energy metabolism, neurogenetic pathological changes and memory dysfunction caused by sleep deprivation were alleviated by SIRT6 overexpression in the DG. CONCLUSION Our results suggest that SIRT6 plays a critical role in maintaining energy metabolism homeostasis in the hippocampus after sleep deprivation, promoting hippocampal neurogenesis and enhancing memory during development.
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Affiliation(s)
- Junke Jia
- Department of Anesthesiology, Zhongnan Hospital, Wuhan University, East Lake Road, Wuhan, 430071, Hubei, China
| | - Wanjiang Tao
- Department of Anesthesiology, Zhongnan Hospital, Wuhan University, East Lake Road, Wuhan, 430071, Hubei, China
| | - Ting Chen
- Department of Anesthesiology, Zhongnan Hospital, Wuhan University, East Lake Road, Wuhan, 430071, Hubei, China
| | - Qi Zhong
- Department of Anesthesiology, Zhongnan Hospital, Wuhan University, East Lake Road, Wuhan, 430071, Hubei, China
| | - Jiahui Sun
- Department of Anesthesiology, Zhongnan Hospital, Wuhan University, East Lake Road, Wuhan, 430071, Hubei, China
| | - Yutong Xu
- Department of Anesthesiology, Zhongnan Hospital, Wuhan University, East Lake Road, Wuhan, 430071, Hubei, China
| | - Xiaokai Sui
- Department of Anesthesiology, Zhongnan Hospital, Wuhan University, East Lake Road, Wuhan, 430071, Hubei, China
| | - Chang Chen
- Department of Anesthesiology, Zhongnan Hospital, Wuhan University, East Lake Road, Wuhan, 430071, Hubei, China.
| | - Zongze Zhang
- Department of Anesthesiology, Zhongnan Hospital, Wuhan University, East Lake Road, Wuhan, 430071, Hubei, China.
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5
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Jun JH, Kim JS, Palomera LF, Jo DG. Dysregulation of histone deacetylases in ocular diseases. Arch Pharm Res 2024; 47:20-39. [PMID: 38151648 DOI: 10.1007/s12272-023-01482-x] [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: 06/15/2023] [Accepted: 12/20/2023] [Indexed: 12/29/2023]
Abstract
Ocular diseases are a growing global concern and have a significant impact on the quality of life. Cataracts, glaucoma, age-related macular degeneration, and diabetic retinopathy are the most prevalent ocular diseases. Their prevalence and the global market size are also increasing. However, the available pharmacotherapy is currently limited. These diseases share common pathophysiological features, including neovascularization, inflammation, and/or neurodegeneration. Histone deacetylases (HDACs) are a class of enzymes that catalyze the removal of acetyl groups from lysine residues of histone and nonhistone proteins. HDACs are crucial for regulating various cellular processes, such as gene expression, protein stability, localization, and function. They have also been studied in various research fields, including cancer, inflammatory diseases, neurological disorders, and vascular diseases. Our study aimed to investigate the relationship between HDACs and ocular diseases, to identify a new strategy for pharmacotherapy. This review article explores the role of HDACs in ocular diseases, specifically focusing on diabetic retinopathy, age-related macular degeneration, and retinopathy of prematurity, as well as optic nerve disorders, such as glaucoma and optic neuropathy. Additionally, we explore the interplay between HDACs and key regulators of fibrosis and angiogenesis, such as TGF-β and VEGF, highlighting the potential of targeting HDAC as novel therapeutic strategies for ocular diseases.
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Affiliation(s)
- Jae Hyun Jun
- School of Pharmacy, Sungkyunkwan University, Suwon, 16419, Korea
- Department of Pharmacology, CKD Research Institute, Chong Kun Dang Pharmaceutical Co., Yongin, 16995, Korea
| | - Jun-Sik Kim
- School of Pharmacy, Sungkyunkwan University, Suwon, 16419, Korea
| | - Leon F Palomera
- School of Pharmacy, Sungkyunkwan University, Suwon, 16419, Korea
| | - Dong-Gyu Jo
- School of Pharmacy, Sungkyunkwan University, Suwon, 16419, Korea.
- Samsung Advanced Institute for Health Sciences and Technology, Sungkyunkwan University, Seoul, 06351, Korea.
- Biomedical Institute for Convergence, Sungkyunkwan University, Suwon, 16419, Korea.
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6
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Cheng J, Keuthan CJ, Esumi N. The many faces of SIRT6 in the retina and retinal pigment epithelium. Front Cell Dev Biol 2023; 11:1244765. [PMID: 38016059 PMCID: PMC10646311 DOI: 10.3389/fcell.2023.1244765] [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: 06/23/2023] [Accepted: 10/18/2023] [Indexed: 11/30/2023] Open
Abstract
Sirtuin 6 (SIRT6) is a member of the mammalian sirtuin family of NAD+-dependent protein deacylases, homologues of the yeast silent information regulator 2 (Sir2). SIRT6 has remarkably diverse functions and plays a key role in a variety of biological processes for maintaining cellular and organismal homeostasis. In this review, our primary aim is to summarize recent progress in understanding SIRT6's functions in the retina and retinal pigment epithelium (RPE), with the hope of further drawing interests in SIRT6 to increase efforts in exploring the therapeutic potential of this unique protein in the vision field. Before describing SIRT6's role in the eye, we first discuss SIRT6's general functions in a wide range of biological contexts. SIRT6 plays an important role in gene silencing, metabolism, DNA repair, antioxidant defense, inflammation, aging and longevity, early development, and stress response. In addition, recent studies have revealed SIRT6's role in macrophage polarization and mitochondrial homeostasis. Despite being initially understudied in the context of the eye, recent efforts have begun to elucidate the critical functions of SIRT6 in the retina and RPE. In the retina, SIRT6 is essential for adult retinal function, regulates energy metabolism by suppressing glycolysis that affects photoreceptor cell survival, protects retinal ganglion cells from oxidative stress, and plays a role in Müller cells during early neurodegenerative events in diabetic retinopathy. In the RPE, SIRT6 activates autophagy in culture and protects against oxidative stress in mice. Taken together, this review demonstrates that better understanding of SIRT6's functions and their mechanisms, both in and out of the context of the eye, holds great promise for the development of SIRT6-targeted strategies for prevention and treatment of blinding eye diseases.
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Affiliation(s)
| | | | - Noriko Esumi
- Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD, United States
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Lee SJ, Emery D, Vukmanic E, Wang Y, Lu X, Wang W, Fortuny E, James R, Kaplan HJ, Liu Y, Du J, Dean DC. Metabolic transcriptomics dictate responses of cone photoreceptors to retinitis pigmentosa. Cell Rep 2023; 42:113054. [PMID: 37656622 PMCID: PMC10591869 DOI: 10.1016/j.celrep.2023.113054] [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: 05/08/2023] [Revised: 06/21/2023] [Accepted: 08/15/2023] [Indexed: 09/03/2023] Open
Abstract
Most mutations in retinitis pigmentosa (RP) arise in rod photoreceptors, but cone photoreceptors, responsible for high-resolution daylight and color vision, are subsequently affected, causing the most debilitating features of the disease. We used mass spectroscopy to follow 13C metabolites delivered to the outer retina and single-cell RNA sequencing to assess photoreceptor transcriptomes. The S cone metabolic transcriptome suggests engagement of the TCA cycle and ongoing response to ROS characteristic of oxidative phosphorylation, which we link to their histone modification transcriptome. Tumor necrosis factor (TNF) and its downstream effector RIP3, which drive ROS generation via mitochondrial dysfunction, are induced and activated as S cones undergo early apoptosis in RP. The long/medium-wavelength (L/M) cone transcriptome shows enhanced glycolytic capacity, which maintains their function as RP progresses. Then, as extracellular glucose eventually diminishes, L/M cones are sustained in long-term dormancy by lactate metabolism.
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Affiliation(s)
- Sang Joon Lee
- Department of Medicine, Brown Cancer Center, University of Louisville Health Sciences Center, Louisville, KY 40202, USA; Department of Ophthalmology, Kosin University College of Medicine, #262 Gamcheon-ro, Seo-gu, Busan 49267, Korea
| | - Douglas Emery
- Department of Medicine, Brown Cancer Center, University of Louisville Health Sciences Center, Louisville, KY 40202, USA
| | - Eric Vukmanic
- Department of Medicine, Brown Cancer Center, University of Louisville Health Sciences Center, Louisville, KY 40202, USA
| | - Yekai Wang
- Departments of Ophthalmology and Visual Sciences and Biochemistry and Molecular Medicine, West Virginia University, Morgantown, WV 26506, USA
| | - Xiaoqin Lu
- Department of Medicine, Brown Cancer Center, University of Louisville Health Sciences Center, Louisville, KY 40202, USA
| | - Wei Wang
- Department of Ophthalmology and Visual Sciences, University of Louisville Health Sciences Center, Louisville, KY 40202, USA
| | - Enzo Fortuny
- Department of Neurosurgery, University of Louisville Health Sciences Center, Louisville, KY 40202, USA
| | - Robert James
- Department of Neurosurgery, University of Louisville Health Sciences Center, Louisville, KY 40202, USA
| | - Henry J Kaplan
- Department of Ophthalmology, St. Louis University School of Medicine, St. Louis MO 63110, USA
| | - Yongqing Liu
- Department of Medicine, Brown Cancer Center, University of Louisville Health Sciences Center, Louisville, KY 40202, USA
| | - Jianhai Du
- Departments of Ophthalmology and Visual Sciences and Biochemistry and Molecular Medicine, West Virginia University, Morgantown, WV 26506, USA.
| | - Douglas C Dean
- Department of Medicine, Brown Cancer Center, University of Louisville Health Sciences Center, Louisville, KY 40202, USA.
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8
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Takata N, Miska JM, Morgan MA, Patel P, Billingham LK, Joshi N, Schipma MJ, Dumar ZJ, Joshi NR, Misharin AV, Embry RB, Fiore L, Gao P, Diebold LP, McElroy GS, Shilatifard A, Chandel NS, Oliver G. Lactate-dependent transcriptional regulation controls mammalian eye morphogenesis. Nat Commun 2023; 14:4129. [PMID: 37452018 PMCID: PMC10349100 DOI: 10.1038/s41467-023-39672-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Accepted: 06/26/2023] [Indexed: 07/18/2023] Open
Abstract
Mammalian retinal metabolism favors aerobic glycolysis. However, the role of glycolytic metabolism in retinal morphogenesis remains unknown. We report that aerobic glycolysis is necessary for the early stages of retinal development. Taking advantage of an unbiased approach that combines the use of eye organoids and single-cell RNA sequencing, we identify specific glucose transporters and glycolytic genes in retinal progenitors. Next, we determine that the optic vesicle territory of mouse embryos displays elevated levels of glycolytic activity. At the functional level, we show that removal of Glucose transporter 1 and Lactate dehydrogenase A gene activity from developing retinal progenitors arrests eye morphogenesis. Surprisingly, we uncover that lactate-mediated upregulation of key eye-field transcription factors is controlled by the epigenetic modification of histone H3 acetylation through histone deacetylase activity. Our results identify an unexpected bioenergetic independent role of lactate as a signaling molecule necessary for mammalian eye morphogenesis.
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Affiliation(s)
- Nozomu Takata
- Center for Vascular and Developmental Biology, Feinberg Cardiovascular and Renal Research Institute, Feinberg School of Medicine, Northwestern University, Chicago, IL, 60611, USA
- Simpson Querrey Institute for BioNanotechnology, Northwestern University, 303 E. Superior Street, Chicago, IL, 60611, USA
| | - Jason M Miska
- Department of Neurological Surgery, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
- Northwestern Medicine Malnati Brain Tumor Institute of the Lurie Comprehensive Cancer Center, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Marc A Morgan
- Simpson Querrey Institute for Epigenetics and Department of Biochemistry and Molecular Genetics, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
- Department of Oncology, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA
| | - Priyam Patel
- Center for Genetic Medicine, Northwestern University, Chicago, IL, 60611, USA
| | - Leah K Billingham
- Department of Neurological Surgery, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Neha Joshi
- Center for Genetic Medicine, Northwestern University, Chicago, IL, 60611, USA
| | - Matthew J Schipma
- Center for Genetic Medicine, Northwestern University, Chicago, IL, 60611, USA
| | - Zachary J Dumar
- Simpson Querrey Institute for Epigenetics and Department of Biochemistry and Molecular Genetics, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Nikita R Joshi
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, Northwestern University, Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Alexander V Misharin
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, Northwestern University, Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Ryan B Embry
- Center for Genetic Medicine, Northwestern University, Chicago, IL, 60611, USA
| | - Luciano Fiore
- Center for Vascular and Developmental Biology, Feinberg Cardiovascular and Renal Research Institute, Feinberg School of Medicine, Northwestern University, Chicago, IL, 60611, USA
- Laboratory of Nanomedicine, National Atomic Energy Commission (CNEA), Av. General Paz 1499, B1650KNA, San Martín, Buenos Aires, Argentina
| | - Peng Gao
- Robert H. Lurie Cancer Center Metabolomics Core, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Lauren P Diebold
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, Northwestern University, Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Gregory S McElroy
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, Northwestern University, Feinberg School of Medicine, Chicago, IL, 60611, USA
- Department of Ophthalmology, Duke University School of Medicine, Durham, NC, 27710, USA
| | - Ali Shilatifard
- Simpson Querrey Institute for Epigenetics and Department of Biochemistry and Molecular Genetics, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Navdeep S Chandel
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, Northwestern University, Feinberg School of Medicine, Chicago, IL, 60611, USA
- Department of Biochemistry and Molecular Genetics, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Guillermo Oliver
- Center for Vascular and Developmental Biology, Feinberg Cardiovascular and Renal Research Institute, Feinberg School of Medicine, Northwestern University, Chicago, IL, 60611, USA.
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9
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Yang X, Chung JY, Rai U, Esumi N. SIRT6 overexpression in the nucleus protects mouse retinal pigment epithelium from oxidative stress. Life Sci Alliance 2023; 6:e202201448. [PMID: 37185874 PMCID: PMC10130745 DOI: 10.26508/lsa.202201448] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 04/05/2023] [Accepted: 04/06/2023] [Indexed: 05/17/2023] Open
Abstract
Retinal pigment epithelium (RPE) is essential for the survival of retinal photoreceptors. To study retinal degeneration, sodium iodate (NaIO3) has been used to cause oxidative stress-induced RPE death followed by photoreceptor degeneration. However, analyses of RPE damage itself are still limited. Here, we characterized NaIO3-induced RPE damage, which was divided into three regions: periphery with normal-shaped RPE, transitional zone with elongated cells, and center with severely damaged or lost RPE. Elongated cells in the transitional zone exhibited molecular characteristics of epithelial-mesenchymal transition. Central RPE was more susceptible to stresses than peripheral RPE. Under stresses, SIRT6, an NAD+-dependent protein deacylase, rapidly translocated from the nucleus to the cytoplasm and colocalized with stress granule factor G3BP1, leading to nuclear SIRT6 depletion. To overcome this SIRT6 depletion, SIRT6 overexpression was induced in the nucleus in transgenic mice, which protected RPE from NaIO3 and partially preserved catalase expression. These results demonstrate topological differences of mouse RPE and warrant further exploring SIRT6 as a potential target for protecting RPE from oxidative stress-induced damage.
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Affiliation(s)
- Xue Yang
- Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Jin-Yong Chung
- Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Usha Rai
- Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Noriko Esumi
- Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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10
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Wang NK, Liu PK, Kong Y, Tseng YJ, Jenny LA, Nolan ND, Chen N, Wang HH, Hsu CW, Huang WC, Sparrow JR, Lin CS, Tsang SH. Spatiotemporal control of genome engineering in cone photoreceptors. Cell Biosci 2023; 13:119. [PMID: 37381060 PMCID: PMC10304375 DOI: 10.1186/s13578-023-01033-3] [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: 12/02/2022] [Accepted: 04/15/2023] [Indexed: 06/30/2023] Open
Abstract
BACKGROUND Cones are essential for color recognition, high resolution, and central vision; therefore cone death causes blindness. Understanding the pathophysiology of each cell type in the retina is key to developing therapies for retinal diseases. However, studying the biology of cone cells in the rod-dominant mammalian retina is particularly challenging. In this study, we used a bacterial artificial chromosome (BAC) recombineering method to knock in the "CreERT2" sequence into the Gnat2 and Arr3 genes, respectively and generated three novel inducible CreERT2 mice with different cone cell specificities. RESULTS These models (Gnat2CreERT2, Arr3T2ACreERT2, and Arr3P2ACreERT2) express temporally controllable Cre recombinase that achieves conditional alleles in cone photoreceptors. Cre-LoxP recombination can be induced as early as postnatal day (PD) two upon tamoxifen injection at varying efficiencies, ranging from 10 to 15% in Gnat2CreERT2, 40% in Arr3T2ACreERT2, and 100% in Arr3P2ACreERT2. Notably, knocking in the P2A-CreERT2 cassette does not affect cone cell morphology and functionality. Most cone-phototransduction enzymes, including Opsins, CNGA3, etc. are not altered except for a reduction in the Arr3 transcript. CONCLUSIONS The Arr3P2ACreERT2 mouse, an inducible cone-specific Cre driver, is a valuable line in studying cone cell biology, function, as well as its relationship with rod and other retinal cells. Moreover, the Cre activity can be induced by delivering tamoxifen intragastrically as early as PD2, which will be useful for studying retinal development or in rapid degenerative mouse models.
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Affiliation(s)
- Nan-Kai Wang
- Edward S. Harkness Eye Institute, Department of Ophthalmology, Columbia University Irving Medical Center, New York, NY, 10032, USA.
- Vagelos College of Physicians and Surgeons, Columbia University, New York, USA.
| | - Pei-Kang Liu
- Edward S. Harkness Eye Institute, Department of Ophthalmology, Columbia University Irving Medical Center, New York, NY, 10032, USA
- 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
| | - Yang Kong
- Edward S. Harkness Eye Institute, Department of Ophthalmology, Columbia University Irving Medical Center, New York, NY, 10032, USA
| | - Yun-Ju Tseng
- Edward S. Harkness Eye Institute, Department of Ophthalmology, Columbia University Irving Medical Center, New York, NY, 10032, USA
| | - Laura A Jenny
- Edward S. Harkness Eye Institute, Department of Ophthalmology, Columbia University Irving Medical Center, New York, NY, 10032, USA
| | - Nicholas D Nolan
- Edward S. Harkness Eye Institute, Department of Ophthalmology, Columbia University Irving Medical Center, New York, NY, 10032, USA
- Department of Biomedical Engineering, The Fu Foundation School of Engineering and Applied Science, Columbia University, New York, NY, 10027, USA
| | - Nelson Chen
- Edward S. Harkness Eye Institute, Department of Ophthalmology, Columbia University Irving Medical Center, New York, NY, 10032, USA
- Faculty of Health Sciences, Queen's University, Kingston, ON, Canada
| | - Hung-Hsi Wang
- Edward S. Harkness Eye Institute, Department of Ophthalmology, Columbia University Irving Medical Center, New York, NY, 10032, USA
- College of Arts and Sciences, University of Miami, Coral Gables, FL, USA
| | - Chun Wei Hsu
- Edward S. Harkness Eye Institute, Department of Ophthalmology, Columbia University Irving Medical Center, New York, NY, 10032, USA
| | - Wan-Chun Huang
- Edward S. Harkness Eye Institute, Department of Ophthalmology, Columbia University Irving Medical Center, New York, NY, 10032, USA
| | - Janet R Sparrow
- Departments of Ophthalmology, Pathology and Cell Biology, Columbia University, New York, USA
| | - Chyuan-Sheng Lin
- Department of Pathology & Cell Biology, Columbia University Irving Medical Center, New York, NY, 10032, USA
- Herbert Irving Comprehensive Cancer Center, Columbia University Irving Medical Center, New York, NY, 10032, USA
| | - Stephen H Tsang
- Edward S. Harkness Eye Institute, Department of Ophthalmology, Columbia University Irving Medical Center, New York, NY, 10032, USA.
- Jonas Children's Vision Care, and Bernard and Shirlee Brown Glaucoma Laboratory, Columbia Stem Cell Initiative, Departments of Ophthalmology, Pathology and Cell Biology, Institute of Human Nutrition, Vagelos College of Physicians and Surgeons, Columbia University, New York, USA.
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11
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Wubben TJ, Chaudhury S, Watch BT, Stuckey JA, Weh E, Fernando R, Goswami M, Pawar M, Rech JC, Besirli CG. Development of Novel Small-Molecule Activators of Pyruvate Kinase Muscle Isozyme 2, PKM2, to Reduce Photoreceptor Apoptosis. Pharmaceuticals (Basel) 2023; 16:ph16050705. [PMID: 37242488 DOI: 10.3390/ph16050705] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Revised: 05/01/2023] [Accepted: 05/04/2023] [Indexed: 05/28/2023] Open
Abstract
Treatment options are lacking to prevent photoreceptor death and subsequent vision loss. Previously, we demonstrated that reprogramming metabolism via the pharmacologic activation of PKM2 is a novel photoreceptor neuroprotective strategy. However, the features of the tool compound used in those studies, ML-265, preclude its advancement as an intraocular, clinical candidate. This study sought to develop the next generation of small-molecule PKM2 activators, aimed specifically for delivery into the eye. Compounds were developed that replaced the thienopyrrolopyridazinone core of ML-265 and modified the aniline and methyl sulfoxide functional groups. Compound 2 demonstrated that structural changes to the ML-265 scaffold are tolerated from a potency and efficacy standpoint, allow for a similar binding mode to the target, and circumvent apoptosis in models of outer retinal stress. To overcome the low solubility and problematic functional groups of ML-265, compound 2's efficacious and versatile core structure for the incorporation of diverse functional groups was then utilized to develop novel PKM2 activators with improved solubility, lack of structural alerts, and retained potency. No other molecules are in the pharmaceutical pipeline for the metabolic reprogramming of photoreceptors. Thus, this study is the first to cultivate the next generation of novel, structurally diverse, small-molecule PKM2 activators for delivery into the eye.
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Affiliation(s)
- Thomas J Wubben
- Department of Ophthalmology and Visual Sciences, Kellogg Eye Center, University of Michigan, Ann Arbor, MI 48105, USA
| | - Sraboni Chaudhury
- Department of Ophthalmology and Visual Sciences, Kellogg Eye Center, University of Michigan, Ann Arbor, MI 48105, USA
| | - Brennan T Watch
- Department of Internal Medicine, Hematology and Oncology, Michigan Center for Therapeutic Innovation, University of Michigan, Ann Arbor, MI 48109, USA
| | - Jeanne A Stuckey
- Departments of Biological Chemistry and Biophysics, Center for Structural Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Eric Weh
- Department of Ophthalmology and Visual Sciences, Kellogg Eye Center, University of Michigan, Ann Arbor, MI 48105, USA
| | - Roshini Fernando
- Department of Ophthalmology and Visual Sciences, Kellogg Eye Center, University of Michigan, Ann Arbor, MI 48105, USA
| | - Moloy Goswami
- Department of Ophthalmology and Visual Sciences, Kellogg Eye Center, University of Michigan, Ann Arbor, MI 48105, USA
| | - Mercy Pawar
- Department of Ophthalmology and Visual Sciences, Kellogg Eye Center, University of Michigan, Ann Arbor, MI 48105, USA
| | - Jason C Rech
- Department of Internal Medicine, Hematology and Oncology, Michigan Center for Therapeutic Innovation, University of Michigan, Ann Arbor, MI 48109, USA
| | - Cagri G Besirli
- Department of Ophthalmology and Visual Sciences, Kellogg Eye Center, University of Michigan, Ann Arbor, MI 48105, USA
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12
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John MC, Quinn J, Hu ML, Cehajic-Kapetanovic J, Xue K. Gene-agnostic therapeutic approaches for inherited retinal degenerations. Front Mol Neurosci 2023; 15:1068185. [PMID: 36710928 PMCID: PMC9881597 DOI: 10.3389/fnmol.2022.1068185] [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: 10/12/2022] [Accepted: 12/12/2022] [Indexed: 01/11/2023] Open
Abstract
Inherited retinal diseases (IRDs) are associated with mutations in over 250 genes and represent a major cause of irreversible blindness worldwide. While gene augmentation or gene editing therapies could address the underlying genetic mutations in a small subset of patients, their utility remains limited by the great genetic heterogeneity of IRDs and the costs of developing individualised therapies. Gene-agnostic therapeutic approaches target common pathogenic pathways that drive retinal degeneration or provide functional rescue of vision independent of the genetic cause, thus offering potential clinical benefits to all IRD patients. Here, we review the key gene-agnostic approaches, including retinal cell reprogramming and replacement, neurotrophic support, immune modulation and optogenetics. The relative benefits and limitations of these strategies and the timing of clinical interventions are discussed.
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Affiliation(s)
- Molly C. John
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - Joel Quinn
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - Monica L. Hu
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - Jasmina Cehajic-Kapetanovic
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, United Kingdom
| | - Kanmin Xue
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, United Kingdom
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13
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Nolan ND, Jenny LA, Tsang SH, Cui X. Rod Photoreceptor-Specific Ablation of Metformin Target, AMPK, in a Preclinical Model of Autosomal Recessive Retinitis Pigmentosa. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1415:403-408. [PMID: 37440064 DOI: 10.1007/978-3-031-27681-1_59] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/14/2023]
Abstract
Retinal gene therapies have shown tremendous progress in the past decade, but the sheer number of disease-causing mutations makes their applicability challenging. In this study we test our hypothesis that retinitis pigmentosa-associated retinal degeneration can be prevented through AMP-activated protein kinase (AMPK)-associated metabolic pathway reprogramming using a gene-independent model of degeneration and rescue. We show that recue of photoreceptor structure and function is not achieved through our model of metabolic reprogramming. These results suggest that RP may not be treatable through AMPK pathway modulation-based therapies.
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Affiliation(s)
- Nicholas D Nolan
- Department of Biomedical Engineering, Columbia University, New York, NY, USA
- Edward S. Harkness Eye Institute, Department of Ophthalmology, Columbia University Irving Medical Center/New York-Presbyterian Hospital, New York, NY, USA
- Jonas Children's Vision Care, and Bernard & Shirlee Brown Glaucoma Laboratory, Department of Ophthalmology, Columbia University, New York, NY, USA
- Columbia Stem Cell Initiative, Columbia University, New York, NY, USA
| | - Laura A Jenny
- Edward S. Harkness Eye Institute, Department of Ophthalmology, Columbia University Irving Medical Center/New York-Presbyterian Hospital, New York, NY, USA
- Jonas Children's Vision Care, and Bernard & Shirlee Brown Glaucoma Laboratory, Department of Ophthalmology, Columbia University, New York, NY, USA
| | - Stephen H Tsang
- Department of Biomedical Engineering, Columbia University, New York, NY, USA
- Edward S. Harkness Eye Institute, Department of Ophthalmology, Columbia University Irving Medical Center/New York-Presbyterian Hospital, New York, NY, USA
- Jonas Children's Vision Care, and Bernard & Shirlee Brown Glaucoma Laboratory, Department of Ophthalmology, Columbia University, New York, NY, USA
- Columbia Stem Cell Initiative, Columbia University, New York, NY, USA
- Department of Pathology & Cell Biology, Columbia University, New York, NY, USA
- Institute of Human Nutrition, Columbia University, New York, NY, USA
| | - Xuan Cui
- Edward S. Harkness Eye Institute, Department of Ophthalmology, Columbia University Irving Medical Center/New York-Presbyterian Hospital, New York, NY, USA.
- Jonas Children's Vision Care, and Bernard & Shirlee Brown Glaucoma Laboratory, Department of Ophthalmology, Columbia University, New York, NY, USA.
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14
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Lin R, Yu J. The role of NAD + metabolism in macrophages in age-related macular degeneration. Mech Ageing Dev 2023; 209:111755. [PMID: 36435209 DOI: 10.1016/j.mad.2022.111755] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Revised: 11/05/2022] [Accepted: 11/21/2022] [Indexed: 11/24/2022]
Abstract
Age-related macular degeneration (AMD) is a leading cause of legal blindness and moderate and severe vision impairment (MSVI) in people older than 50 years. It is classified in various stages including early, intermediate, and late stage. In the early stages, innate immune system, especially macrophages, play an essential part in disease onset and progression. NAD+ is an essential coenzyme involved in cellular senescence and immune cell function, and its role in age-related diseases is gaining increasing attention. The imbalance between the NAD+ synthesis and consumption causes the fluctuation of intracellular NAD+ level which determines the polarization fate of macrophages. In AMD, the over-expression of NAD+-consuming enzymes in macrophages leads to declining of NAD+ concentrations in the microenvironment. This phenomenon triggers the activation of inflammatory pathways in macrophages, positive feedback aggregation of inflammatory cells and accumulation of reactive oxygen species (ROS). This review details the role of NAD+ metabolism in macrophages and molecular mechanisms during AMD. The selected pathways were identified as potential targets for intervention in AMD, pending further investigation.
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Affiliation(s)
- Ruoyi Lin
- Department of Ophthalmology, the Tenth People's Hospital Affiliated to Tongji University, Tongji University School of Medicine, Shanghai 200072, China
| | - Jing Yu
- Department of Ophthalmology, the Tenth People's Hospital Affiliated to Tongji University, Tongji University School of Medicine, Shanghai 200072, China; Department of Ophthalmology, Bengbu Third People's Hospital, Bengbu, Anhui 233099, China.
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15
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Cui X, Chang YJ, Jenny LA, Levi SR, Du J, Tsang SH. Metabolite Extraction from RPE Cells and Retinas Related to Retinitis Pigmentosa. Methods Mol Biol 2022; 2560:257-265. [PMID: 36481902 DOI: 10.1007/978-1-0716-2651-1_24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The application of metabolomics in ophthalmology helps to identify new biomarkers and elucidate disease mechanisms in different eye diseases, as well as aiding in the development of potential treatment options. Extracting metabolites successfully is essential for potential further analysis using mass spectrometry. In this chapter, we describe how to extract metabolites from a variety of sources including (1) cells on a dish, (2) cell culture medium, and (3) tissues in vivo with and without stable isotope tracers. Samples prepared using this protocol are suitable for a range of downstream mass spectrometry analyses and are stable in solvent for weeks at -80 °C.
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Affiliation(s)
- Xuan Cui
- Edward S. Harkness Eye Institute, Department of Ophthalmology, Columbia University Irving Medical Center, New York, NY, USA.,Jonas Children's Vision Care and Bernard & Shirlee Brown Glaucoma Laboratory, New York, NY, USA
| | - Ya-Ju Chang
- Edward S. Harkness Eye Institute, Department of Ophthalmology, Columbia University Irving Medical Center, New York, NY, USA.,Jonas Children's Vision Care and Bernard & Shirlee Brown Glaucoma Laboratory, New York, NY, USA
| | - Laura A Jenny
- Edward S. Harkness Eye Institute, Department of Ophthalmology, Columbia University Irving Medical Center, New York, NY, USA.,Jonas Children's Vision Care and Bernard & Shirlee Brown Glaucoma Laboratory, New York, NY, USA
| | - Sarah R Levi
- Edward S. Harkness Eye Institute, Department of Ophthalmology, Columbia University Irving Medical Center, New York, NY, USA.,Jonas Children's Vision Care and Bernard & Shirlee Brown Glaucoma Laboratory, New York, NY, USA
| | - Jianhai Du
- Department of Ophthalmology, Department of Biochemistry, West Virginia University, Morgantown, WV, USA
| | - Stephen H Tsang
- Departments of Ophthalmology, Pathology & Cell Biology, Graduate Programs in Nutritional & Metabolic Biology and Neurobiology & Behavior, Columbia Stem Cell Initiative, New York, NY, USA.
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16
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Chidlow G, Chan WO, Wood JPM, Casson RJ. Investigations into photoreceptor energy metabolism during experimental retinal detachment. Front Cell Neurosci 2022; 16:1036834. [PMID: 36467607 PMCID: PMC9716104 DOI: 10.3389/fncel.2022.1036834] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Accepted: 11/01/2022] [Indexed: 08/27/2023] Open
Abstract
Retinal detachment is a sight-threatening disorder, which occurs when the photoreceptors are separated from their vascular supply. The aim of the present study was to shed light on photoreceptor energy metabolism during experimental detachment in rats. Retinal detachment was induced in the eyes of rats via subretinal injection of sodium hyaluronate. Initially, we investigated whether detachment caused hypoxia within photoreceptors, as evaluated by the exogenous and endogenous biomarkers pimonidazole and HIF-1α, as well as by qPCR analysis of HIF target genes. The results showed no unequivocal staining for pimonidazole or HIF-1α within any detached retina, nor upregulation of HIF target genes, suggesting that any reduction in pO2 is of insufficient magnitude to produce hypoxia-induced covalent protein adducts or HIF-1α stabilisation. Subsequently, we analysed expression of cellular bioenergetic enzymes in photoreceptors during detachment. We documented loss of mitochondrial, and downregulation of glycolytic enzymes during detachment, indicating that photoreceptors have reduced energetic requirements and/or capacity. Given that detachment did not cause widespread hypoxia, but did result in downregulated expression of bioenergetic enzymes, we hypothesised that substrate insufficiency may be critical in terms of pathogenesis, and that boosting metabolic inputs may preserve photoreceptor bioenergetic production and, protect against their degeneration. Thus, we tested whether supplementation with the bioavailable energy substrate pyruvate mitigated rod and cone injury and degeneration. Despite protecting photoreceptors in culture from nutrient deprivation, pyruvate failed to protect against apoptotic death of rods, loss of cone opsins, and loss of inner segment mitochondria, in situ, when evaluated at 3 days after detachment. The regimen was also ineffective against cumulative photoreceptor deconstruction and degeneration when evaluated after 4 weeks. Retinal metabolism, particularly the bioenergetic profiles and pathological responses of the various cellular subtypes still presents a considerable knowledge gap that has important clinical consequences. While our data do not support the use of pyruvate supplementation as a means of protecting detached photoreceptors, they do provide a foundation and motivation for future research in this area.
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Affiliation(s)
- Glyn Chidlow
- Ophthalmic Research Laboratories, Discipline of Ophthalmology and Visual Sciences, University of Adelaide, Adelaide, SA, Australia
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17
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Sirtuin 6 inhibition protects against glucocorticoid-induced skeletal muscle atrophy by regulating IGF/PI3K/AKT signaling. Nat Commun 2022; 13:5415. [PMID: 36109503 PMCID: PMC9478160 DOI: 10.1038/s41467-022-32905-w] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Accepted: 08/24/2022] [Indexed: 01/05/2023] Open
Abstract
Chronic activation of stress hormones such as glucocorticoids leads to skeletal muscle wasting in mammals. However, the molecular events that mediate glucocorticoid-induced muscle wasting are not well understood. Here, we show that SIRT6, a chromatin-associated deacetylase indirectly regulates glucocorticoid-induced muscle wasting by modulating IGF/PI3K/AKT signaling. Our results show that SIRT6 levels are increased during glucocorticoid-induced reduction of myotube size and during skeletal muscle atrophy in mice. Notably, overexpression of SIRT6 spontaneously decreases the size of primary myotubes in a cell-autonomous manner. On the other hand, SIRT6 depletion increases the diameter of myotubes and protects them against glucocorticoid-induced reduction in myotube size, which is associated with enhanced protein synthesis and repression of atrogenes. In line with this, we find that muscle-specific SIRT6 deficient mice are resistant to glucocorticoid-induced muscle wasting. Mechanistically, we find that SIRT6 deficiency hyperactivates IGF/PI3K/AKT signaling through c-Jun transcription factor-mediated increase in IGF2 expression. The increased activation, in turn, leads to nuclear exclusion and transcriptional repression of the FoxO transcription factor, a key activator of muscle atrophy. Further, we find that pharmacological inhibition of SIRT6 protects against glucocorticoid-induced muscle wasting in mice by regulating IGF/PI3K/AKT signaling implicating the role of SIRT6 in glucocorticoid-induced muscle atrophy.
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18
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Das A, Imanishi Y. Drug Discovery Strategies for Inherited Retinal Degenerations. BIOLOGY 2022; 11:1338. [PMID: 36138817 PMCID: PMC9495580 DOI: 10.3390/biology11091338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Revised: 08/31/2022] [Accepted: 09/07/2022] [Indexed: 12/03/2022]
Abstract
Inherited retinal degeneration is a group of blinding disorders afflicting more than 1 in 4000 worldwide. These disorders frequently cause the death of photoreceptor cells or retinal ganglion cells. In a subset of these disorders, photoreceptor cell death is a secondary consequence of retinal pigment epithelial cell dysfunction or degeneration. This manuscript reviews current efforts in identifying targets and developing small molecule-based therapies for these devastating neuronal degenerations, for which no cures exist. Photoreceptors and retinal ganglion cells are metabolically demanding owing to their unique structures and functional properties. Modulations of metabolic pathways, which are disrupted in most inherited retinal degenerations, serve as promising therapeutic strategies. In monogenic disorders, great insights were previously obtained regarding targets associated with the defective pathways, including phototransduction, visual cycle, and mitophagy. In addition to these target-based drug discoveries, we will discuss how phenotypic screening can be harnessed to discover beneficial molecules without prior knowledge of their mechanisms of action. Because of major anatomical and biological differences, it has frequently been challenging to model human inherited retinal degeneration conditions using small animals such as rodents. Recent advances in stem cell-based techniques are opening new avenues to obtain pure populations of human retinal ganglion cells and retinal organoids with photoreceptor cells. We will discuss concurrent ideas of utilizing stem-cell-based disease models for drug discovery and preclinical development.
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Affiliation(s)
- Arupratan Das
- Department of Ophthalmology, Eugene and Marilyn Glick Eye Institute, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Yoshikazu Imanishi
- Department of Ophthalmology, Eugene and Marilyn Glick Eye Institute, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
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19
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Duan F, Xiao Z, Wang Y, Sun X, Tang Z, Wang R, Guo L, Tang W, Liu T, Wang P, Zhan Y. Metabolic alterations in the visual pathway of retinitis pigmentosa rats: A longitudinal multimodal magnetic resonance imaging study with histopathological validation. NMR IN BIOMEDICINE 2022; 35:e4751. [PMID: 35478360 DOI: 10.1002/nbm.4751] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 04/12/2022] [Accepted: 04/25/2022] [Indexed: 06/14/2023]
Abstract
Because retinitis pigmentosa (RP) has been shown to cause degenerative changes in the entire visual pathway, there is an urgent need to perform longitudinal assessments of RP-induced degeneration and identify imaging protocols to detect this degeneration as early as possible. In this study, we assessed a transgenic rat model of RP by using complementary noninvasive magnetic resonance imaging techniques, namely, proton magnetic resonance spectroscopy (1 H-MRS), to investigate the metabolic changes in RP. Our study demonstrated decreased concentrations and ratios to creatine (Cr) of N-acetylaspartate (NAA), glutamate (Glu), γ-aminobutyric acid (GABA), and taurine (Tau), whereas myo-inositol (Ins) and choline (Cho) were increased in the visual cortex of Royal College of Surgeons (RCS) rats compared with control rats (p < 0.05). Furthermore, with the progression of RP, the concentrations of NAA, Glu, GABA, and Tau, and the ratios of GABA/Cr and Tau/Cr significantly decreased over time, whereas the concentrations of Ins and Cho and the ratio of Ins/Cr significantly increased over time (p < 0.05). In addition, in RCS rats, NAA/Cr decreased significantly from 3 to 4 months postnatal (p < 0.001), and Cho/Cr increased significantly from 4 to 5 months postnatal (p = 0.005). Meanwhile, the 1 H-MRS indicators in 5-month postnatal RCS rats could be confirmed by immunohistochemical staining. In conclusion, with the progression of RP, the metabolic alterations in the visual cortex indicated progressive reprogramming with the decrease of neurons and axons, accompanied by the proliferation of gliocytes.
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Affiliation(s)
- Fei Duan
- Department of Radiology, Eye & ENT Hospital of Fudan University, Shanghai Medical School, Fudan University, Shanghai, China
| | - Zebin Xiao
- Department of Radiology, Eye & ENT Hospital of Fudan University, Shanghai Medical School, Fudan University, Shanghai, China
| | - Yuzhe Wang
- Department of Radiology, Eye & ENT Hospital of Fudan University, Shanghai Medical School, Fudan University, Shanghai, China
| | - Xinghuai Sun
- Department of Ophthalmology & Visual Science, Eye & ENT Hospital of Fudan University, Shanghai Medical School, Fudan University, Shanghai, China
- State Key Laboratory of Medical Neurobiology, Institutes of Brain Science, Fudan University, Shanghai, China
- Key Laboratory of Myopia, NHFPC (Fudan University), Shanghai, China
- Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai, China
| | - Zuohua Tang
- Department of Radiology, Eye & ENT Hospital of Fudan University, Shanghai Medical School, Fudan University, Shanghai, China
| | - Rong Wang
- Department of Radiology, Eye & ENT Hospital of Fudan University, Shanghai Medical School, Fudan University, Shanghai, China
- Department of Radiology, Huashan Hospital of Fudan University, Shanghai Medical School, Fudan University, Shanghai, China
| | - Linying Guo
- Department of Radiology, Eye & ENT Hospital of Fudan University, Shanghai Medical School, Fudan University, Shanghai, China
| | - Weijun Tang
- Department of Radiology, Huashan Hospital of Fudan University, Shanghai Medical School, Fudan University, Shanghai, China
| | - Tingting Liu
- Department of Ophthalmology & Visual Science, Eye & ENT Hospital of Fudan University, Shanghai Medical School, Fudan University, Shanghai, China
| | - Peng Wang
- Department of Radiology, Eye & ENT Hospital of Fudan University, Shanghai Medical School, Fudan University, Shanghai, China
| | - Yang Zhan
- Department of Radiology, Eye & ENT Hospital of Fudan University, Shanghai Medical School, Fudan University, Shanghai, China
- Shanghai Institute of Medical Imaging, Shanghai, China
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20
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Lewin AS, Smith WC. Gene Therapy for Rhodopsin Mutations. Cold Spring Harb Perspect Med 2022; 12:a041283. [PMID: 35940643 PMCID: PMC9435570 DOI: 10.1101/cshperspect.a041283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Mutations in RHO, the gene for rhodopsin, account for a large fraction of autosomal-dominant retinitis pigmentosa (adRP). Patients fall into two clinical classes, those with early onset, pan retinal photoreceptor degeneration, and those who experience slowly progressive disease. The latter class of patients are candidates for photoreceptor-directed gene therapy, while former may be candidates for delivery of light-responsive proteins to interneurons or retinal ganglion cells. Gene therapy for RHO adRP may be targeted to the mutant gene at the DNA or RNA level, while other therapies preserve the viability of photoreceptors without addressing the underlying mutation. Correcting the RHO gene and replacing the mutant RNA show promise in animal models, while sustaining viable photoreceptors has the potential to delay the loss of central vision and may preserve photoreceptors for gene-directed treatments.
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Affiliation(s)
- Alfred S Lewin
- Departments of Molecular Genetics and Microbiology and Ophthalmology, University of Florida College of Medicine, Gainesville, Florida 32610, USA
| | - W Clay Smith
- Departments of Molecular Genetics and Microbiology and Ophthalmology, University of Florida College of Medicine, Gainesville, Florida 32610, USA
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21
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Nelson TS, Simpson C, Dyka F, Dinculescu A, Smith WC. A Modified Arrestin1 Increases Lactate Production in the Retina and Slows Retinal Degeneration. Hum Gene Ther 2022; 33:695-707. [PMID: 35081746 PMCID: PMC9347377 DOI: 10.1089/hum.2021.272] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Glucose metabolism in the retina is carefully orchestrated, with glucose being delivered to photoreceptors from the choroidal circulation through the retinal pigmented epithelium (RPE). In photoreceptors, glucose is processed principally by aerobic glycolysis, from which the lactate byproduct is provided to the RPE and Müller glia for their energetic needs. In this study, we utilize a modified arrestin1 protein to enhance the glycolytic output of lactate from rod photoreceptors through disinhibition of enolase1 activity with the goal being to use this increased lactate production as a gene-agnostic approach to slowing retinal degeneration. Mouse arrestin1 with E362G/D363G amino acid substitutions (referred to as "ArrGG") was packaged into AAV and tested for safety and for efficacy in increasing retinal lactate production. Overexpression of ArrGG in C57BL/6J mice did not result in any detectable changes in either electroretinogram (ERG) function or photoreceptor survival as measured by outer nuclear layer (ONL) thickness. However, mouse retinas expressing ArrGG showed a ∼25% increase in the rate of lactate secretion. Therefore, AAV-ArrGG was delivered intravitreally to heterozygous P23H rhodopsin knockin mice (RhoP23H/+) to determine if enhancing glycolysis in photoreceptors can slow retinal degeneration in this animal model of retinitis pigmentosa. We found that the expression of ArrGG in these mice slowed the decline of both scotopic and photopic ERG function. Correspondingly, there was significant preservation of ONL thickness in RhoP23H/+ mice treated with ArrGG compared with controls. In conclusion, our studies show that expressing ArrGG in C57BL/6J mouse retina results in an increase in lactate production, consistent with an upregulation of glycolysis. In the P23H rhodopsin model of retinitis pigmentosa, the expression of ArrGG led to significant preservation of photoreceptor function and slowing of retinal degeneration. These findings suggest that enhancing glycolysis by targeting increased enolase1 activity with a modified arrestin1 in photoreceptors may offer a therapeutic approach to slowing retinal degeneration.
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Affiliation(s)
- Tiffany S Nelson
- Department of Ophthalmology, University of Florida, Gainesville, Florida, USA
| | - Chiab Simpson
- Department of Ophthalmology, University of Florida, Gainesville, Florida, USA
| | - Frank Dyka
- Department of Ophthalmology, University of Florida, Gainesville, Florida, USA
| | - Astra Dinculescu
- Department of Ophthalmology, University of Florida, Gainesville, Florida, USA
| | - W Clay Smith
- Department of Ophthalmology, University of Florida, Gainesville, Florida, USA
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22
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Yazdani M. Uncontrolled Oxygen Levels in Cultures of Retinal Pigment Epithelium: Have We Missed the Obvious? Curr Eye Res 2022; 47:651-660. [PMID: 35243933 DOI: 10.1080/02713683.2022.2050264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Retinal pigment epithelium (RPE) is the outermost layer of retina located between the photoreceptor cells and the choroid. This highly-polarized monolayer provides critical support for the functioning of the other parts of the retina, especially photoreceptors. Methods of culturing RPE have been under development since its establishment in 1920s. Despite considering various factors, oxygen (O2) levels in RPE microenvironments during culture preparation and experimental procedure have been overlooked. O2 is a crucial parameter in the cultures, and therefore, maintaining RPE cells at O2 levels different from their native environment (70-90 mm Hg of O2) could have unintended consequences. Owing to the importance of the topic, lack of sufficient discussion in the literature and to encourage future research, this paper will focus on uncontrolled O2 level in cultures of RPE cells.
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Affiliation(s)
- Mazyar Yazdani
- Department of Medical Biochemistry, Oslo University Hospital, Rikshospitalet, 0027 Oslo, Norway
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23
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Renormalization of metabolic coupling treats age-related degenerative disorders: an oxidative RPE niche fuels the more glycolytic photoreceptors. Eye (Lond) 2022; 36:278-283. [PMID: 34974542 PMCID: PMC8807833 DOI: 10.1038/s41433-021-01726-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 07/21/2021] [Accepted: 07/27/2021] [Indexed: 11/26/2022] Open
Abstract
Retinitis pigmentosa is characterized by a dysregulation within the metabolic coupling of the retina, particularly between the glycolytic photoreceptors and the oxidative retina pigment epithelium. This phenomenon of metabolic uncoupling is seen in both aging and retinal degenerative diseases, as well as across a variety of cell types in human biology. Given its crucial role in the health and maintenance of these cell types, the metabolic pathways involved present a suitable area for therapeutic intervention. Herein, this review covers the scope of this delicate metabolic interplay, its dysregulation, how it relates to the retina as well other cell types, and finally concludes with a summary of various strategies aimed at reinstating normal metabolic coupling within the retina, and future directions within the field.
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24
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Jiang K, Mondal AK, Adlakha YK, Gumerson J, Aponte A, Gieser L, Kim JW, Boleda A, Brooks MJ, Nellissery J, Fox DA, Balaban R, Covian R, Swaroop A. Multiomics analyses reveal early metabolic imbalance and mitochondrial stress in neonatal photoreceptors leading to cell death in Pde6brd1/rd1 mouse model of retinal degeneration. Hum Mol Genet 2022; 31:2137-2154. [PMID: 35075486 PMCID: PMC9618164 DOI: 10.1093/hmg/ddac013] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Revised: 12/17/2021] [Accepted: 01/10/2022] [Indexed: 01/26/2023] Open
Abstract
Retinal diseases exhibit extensive genetic heterogeneity and complex etiology with varying onset and severity. Mutations in over 200 genes can lead to photoreceptor dysfunction and/or cell death in retinal neurodegeneration. To deduce molecular pathways that initiate and/or drive cell death, we adopted a temporal multiomics approach and examined molecular and cellular events in newborn and developing photoreceptors before the onset of degeneration in a widely-used Pde6brd1/rd1 (rd1) mouse, a model of autosomal recessive retinitis pigmentosa caused by PDE6B mutations. Transcriptome profiling of neonatal and developing rods from the rd1 retina revealed early downregulation of genes associated with anabolic pathways and energy metabolism. Quantitative proteomics of rd1 retina showed early changes in calcium signaling and oxidative phosphorylation, with specific partial bypass of complex I electron transfer, which precede the onset of cell death. Concurrently, we detected alterations in central carbon metabolism, including dysregulation of components associated with glycolysis, pentose phosphate and purine biosynthesis. Ex vivo assays of oxygen consumption and transmission electron microscopy validated early and progressive mitochondrial stress and abnormalities in mitochondrial structure and function of rd1 rods. These data uncover mitochondrial overactivation and related metabolic alterations as determinants of early pathology and implicate aberrant calcium signaling as an initiator of higher mitochondrial stress. Our studies thus provide a mechanistic framework with mitochondrial damage and metabolic disruptions as early drivers of photoreceptor cell death in retinal degeneration.
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Affiliation(s)
| | | | - Yogita K Adlakha
- Neurobiology, Neurodegeneration & Repair Laboratory, National Eye Institute, National Institutes of Health, 6 Center Drive, Bethesda, MD 20892, USA,Translational Health Science and Technology Institute, National Capital Region Biotech Cluster, Faridabad, India
| | - Jessica Gumerson
- Neurobiology, Neurodegeneration & Repair Laboratory, National Eye Institute, National Institutes of Health, 6 Center Drive, Bethesda, MD 20892, USA
| | - Angel Aponte
- Proteomics Core Facility, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Linn Gieser
- Neurobiology, Neurodegeneration & Repair Laboratory, National Eye Institute, National Institutes of Health, 6 Center Drive, Bethesda, MD 20892, USA
| | - Jung-Woong Kim
- Neurobiology, Neurodegeneration & Repair Laboratory, National Eye Institute, National Institutes of Health, 6 Center Drive, Bethesda, MD 20892, USA,Department of Life Science, College of Natural Sciences, Chung-Ang University, Seoul 06974, Republic of Korea
| | - Alexis Boleda
- Neurobiology, Neurodegeneration & Repair Laboratory, National Eye Institute, National Institutes of Health, 6 Center Drive, Bethesda, MD 20892, USA,Center for Bioinformatics and Computational Biology, University of Maryland, College Park, MD 20740, USA
| | - Matthew J Brooks
- Neurobiology, Neurodegeneration & Repair Laboratory, National Eye Institute, National Institutes of Health, 6 Center Drive, Bethesda, MD 20892, USA
| | - Jacob Nellissery
- Neurobiology, Neurodegeneration & Repair Laboratory, National Eye Institute, National Institutes of Health, 6 Center Drive, Bethesda, MD 20892, USA
| | - Donald A Fox
- Neurobiology, Neurodegeneration & Repair Laboratory, National Eye Institute, National Institutes of Health, 6 Center Drive, Bethesda, MD 20892, USA
| | - Robert Balaban
- Laboratory of Cardiac Energetics, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Raul Covian
- Laboratory of Cardiac Energetics, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Anand Swaroop
- To whom correspondence should be addressed. Tel: +301-435-5754; Fax: 301-480-9917;
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25
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Kaplan HJ, Wang W, Piri N, Dean DC. Metabolic rescue of cone photoreceptors in retinitis pigmentosa. Taiwan J Ophthalmol 2021; 11:331-335. [PMID: 35070660 PMCID: PMC8757513 DOI: 10.4103/tjo.tjo_46_21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2021] [Accepted: 10/05/2021] [Indexed: 12/27/2022] Open
Abstract
Retinitis pigmentosa (RP) encompasses a group of inherited retinal dystrophies characterized by the primary degeneration of rod and cone photoreceptors. It is a leading cause of visual disability, with an incidence of ~1 in 7000 persons. Although most RP is nonsyndromic, 20%-30% of patients with RP also have an associated nonocular condition. The gene mutations responsible for RP occur overwhelmingly in rod photoreceptors. Visual loss frequently begins with night blindness in adolescence, followed by concentric visual field loss, reflecting the principal dysfunction of rod photoreceptors. Although the visual disability from rod dysfunction is significant, it is the subsequent loss of central vision later in life due to cone degeneration that is catastrophic. Until recently, the reason for cone dysfunction in RP was unknown. However, it is now recognized that cones degenerate, losing outer segment (OS) synthesis and inner segment (IS) disassembly because of glucose starvation following rod demise. Rod OS phagocytosis by the apical microvilli of retinal pigment epithelium is necessary to transport glucose from the choriocapillaris to the subretinal space. Although cones lose OS with the onset of rod degeneration in RP, regardless of the gene mutation in rods, cone nuclei remain viable for years (i.e. enter cone dormancy) so that therapies aimed at reversing glucose starvation can prevent and/or recover cone function and central vision.
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Affiliation(s)
- Henry J Kaplan
- Department of Ophthalmology, Saint Louis University School of Medicine, Saint Louis, Missouri, USA
| | - Wei Wang
- Department of Ophthalmology and Visual Sciences, University of Louisville Health Sciences Center, Louisville, Kentucky, USA
| | - Niloofar Piri
- Department of Ophthalmology, Saint Louis University School of Medicine, Saint Louis, Missouri, USA
| | - Douglas C Dean
- Department of Medicine, University of Louisville Health Sciences Center, Louisville, Kentucky, USA
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26
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Yan J, Chen Y, Zhu Y, Paquet-Durand F. Programmed Non-Apoptotic Cell Death in Hereditary Retinal Degeneration: Crosstalk between cGMP-Dependent Pathways and PARthanatos? Int J Mol Sci 2021; 22:10567. [PMID: 34638907 PMCID: PMC8508647 DOI: 10.3390/ijms221910567] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 09/26/2021] [Accepted: 09/27/2021] [Indexed: 12/20/2022] Open
Abstract
Programmed cell death (PCD) is a highly regulated process that results in the orderly destruction of a cell. Many different forms of PCD may be distinguished, including apoptosis, PARthanatos, and cGMP-dependent cell death. Misregulation of PCD mechanisms may be the underlying cause of neurodegenerative diseases of the retina, including hereditary retinal degeneration (RD). RD relates to a group of diseases that affect photoreceptors and that are triggered by gene mutations that are often well known nowadays. Nevertheless, the cellular mechanisms of PCD triggered by disease-causing mutations are still poorly understood, and RD is mostly still untreatable. While investigations into the neurodegenerative mechanisms of RD have focused on apoptosis in the past two decades, recent evidence suggests a predominance of non-apoptotic processes as causative mechanisms. Research into these mechanisms carries the hope that the knowledge created can eventually be used to design targeted treatments to prevent photoreceptor loss. Hence, in this review, we summarize studies on PCD in RD, including on apoptosis, PARthanatos, and cGMP-dependent cell death. Then, we focus on a possible interplay between these mechanisms, covering cGMP-signaling targets, overactivation of poly(ADP-ribose)polymerase (PARP), energy depletion, Ca2+-permeable channels, and Ca2+-dependent proteases. Finally, an outlook is given into how specific features of cGMP-signaling and PARthanatos may be targeted by therapeutic interventions.
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Affiliation(s)
| | | | | | - François Paquet-Durand
- Cell Death Mechanism Group, Institute for Ophthalmic Research, University of Tübingen, Elfriede-Aulhorn-Strasse 7, 72076 Tübingen, Germany; (J.Y.); (Y.C.); (Y.Z.)
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27
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Technological advancements to study cellular signaling pathways in inherited retinal degenerative diseases. Curr Opin Pharmacol 2021; 60:102-110. [PMID: 34388439 DOI: 10.1016/j.coph.2021.07.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Accepted: 07/02/2021] [Indexed: 01/01/2023]
Abstract
Inherited retinal degenerative diseases (IRDs) are rare neurodegenerative disorders with mutations in hundreds of genes leading to vision loss, primarily owing to photoreceptor cell death. This genetic diversity is impeding development of effective treatment options. Gene-based therapies have resulted in the first FDA-approved drug (Luxturna) for RPE65-specific IRD. Although currently explored in clinical trials, genomic medicines are mutation-dependent, hence suitable only for patients harboring a specific mutation. Better understanding of the pathways leading to photoreceptor degeneration may help to determine common targets and develop mutation-independent therapies for larger groups of patients with IRDs. In this review, we discuss the key pathways involved in photoreceptor cell death studied by transcriptomics, proteomics, and metabolomics techniques to identify potential therapeutic targets in IRDs.
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28
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Rowe AA, Patel PD, Gordillo R, Wert KJ. Replenishment of TCA cycle intermediates provides photoreceptor resilience against neurodegeneration during progression of retinitis pigmentosa. JCI Insight 2021; 6:e150898. [PMID: 34292885 PMCID: PMC8492344 DOI: 10.1172/jci.insight.150898] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Accepted: 07/16/2021] [Indexed: 11/24/2022] Open
Abstract
The metabolic environment is important for neuronal cells, such as photoreceptors. When photoreceptors undergo degeneration, as occurs during retinitis pigmentosa (RP), patients have progressive loss of vision that proceeds to full blindness. Currently, there are no available treatments for the majority of RP diseases. We performed metabolic profiling of the neural retina in a preclinical model of RP and found that TCA cycle intermediates were reduced during disease. We then determined that (a) promoting citrate production within the TCA cycle in retinal neurons during disease progression protected the photoreceptors from cell death and prolonged visual function, (b) supplementation with single metabolites within the TCA cycle provided this therapeutic effect in vivo over time, and (c) this therapeutic effect was not specific to a particular genetic mutation but had broad applicability for patients with RP and other retinal degenerative diseases. Overall, targeting TCA cycle activity in the neural retina promoted photoreceptor survival and visual function during neurodegenerative disease.
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Affiliation(s)
- Ashley A Rowe
- Department of Ophthalmology, UT Southwestern Medical Center, Dallas, United States of America
| | - Pinkal D Patel
- Department of Ophthalmology, UT Southwestern Medical Center, Dallas, United States of America
| | - Ruth Gordillo
- Department of Internal Medicine, UT Southwestern Medical Center, Dallas, United States of America
| | - Katherine J Wert
- Department of Ophthalmology, UT Southwestern Medical Center, Dallas, United States of America
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29
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Abstract
The outer retina is nourished from the choroid, a capillary bed just inside the sclera. O2, glucose, and other nutrients diffuse out of the choroid and then filter through a monolayer of retinal pigment epithelium (RPE) cells to fuel the retina. Recent studies of energy metabolism have revealed striking differences between retinas and RPE cells in the ways that they extract energy from fuels. The purpose of this review is to suggest and evaluate the hypothesis that the retina and RPE have complementary metabolic roles that make them depend on each other for survival and for their abilities to perform essential and specialized functions. Expected final online publication date for the Annual Review of Vision Science, Volume 7 is September 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- James B Hurley
- Departments of Biochemistry and Ophthalmology, University of Washington, Seattle, Washington 98115, USA;
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30
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Suppression of PGC-1α Drives Metabolic Dysfunction in TGFβ2-Induced EMT of Retinal Pigment Epithelial Cells. Int J Mol Sci 2021; 22:ijms22094701. [PMID: 33946753 PMCID: PMC8124188 DOI: 10.3390/ijms22094701] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2021] [Revised: 04/24/2021] [Accepted: 04/26/2021] [Indexed: 02/07/2023] Open
Abstract
PGC-1α, a key orchestrator of mitochondrial metabolism, plays a crucial role in governing the energetically demanding needs of retinal pigment epithelial cells (RPE). We previously showed that silencing PGC-1α induced RPE to undergo an epithelial-mesenchymal-transition (EMT). Here, we show that induction of EMT in RPE using transforming growth factor-beta 2 (TGFβ2) suppressed PGC-1α expression. Correspondingly, TGFβ2 induced defects in mitochondrial network integrity with increased sphericity and fragmentation. TGFβ2 reduced expression of genes regulating mitochondrial dynamics, reduced citrate synthase activity and intracellular ATP content. High-resolution respirometry showed that TGFβ2 reduced mitochondrial OXPHOS levels consistent with reduced expression of NDUFB5. The reduced mitochondrial respiration was associated with a compensatory increase in glycolytic reserve, glucose uptake and gene expression of glycolytic enzymes (PFKFB3, PKM2, LDHA). Treatment with ZLN005, a selective small molecule activator of PGC-1α, blocked TGFβ2-induced upregulation of mesenchymal genes (αSMA, Snai1, CTGF, COL1A1) and TGFβ2-induced migration using the scratch wound assay. Our data show that EMT is accompanied by mitochondrial dysfunction and a metabolic shift towards reduced OXPHOS and increased glycolysis that may be driven by PGC-1α suppression. ZLN005 effectively blocks EMT in RPE and thus serves as a novel therapeutic avenue for treatment of subretinal fibrosis.
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31
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Fu Z, Qiu C, Cagnone G, Tomita Y, Huang S, Cakir B, Kotoda Y, Allen W, Bull E, Akula JD, Joyal JS, Hellström A, Talukdar S, Smith LEH. Retinal glial remodeling by FGF21 preserves retinal function during photoreceptor degeneration. iScience 2021; 24:102376. [PMID: 33937726 PMCID: PMC8079476 DOI: 10.1016/j.isci.2021.102376] [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: 01/19/2021] [Revised: 02/13/2021] [Accepted: 03/25/2021] [Indexed: 12/18/2022] Open
Abstract
The group of retinal degenerations, retinitis pigmentosa (RP), comprises more than 150 genetic abnormalities affecting photoreceptors. Finding degenerative pathways common to all genetic abnormalities may allow general treatment such as neuroprotection. Neuroprotection may include enhancing the function of cells that directly support photoreceptors, retinal pigment epithelial cells, and Müller glia. Treatment with fibroblast growth factor 21 (FGF21), a neuroprotectant, from postnatal week 4-10, during rod and cone loss in P23H mice (an RP model) with retinal degeneration, preserved photoreceptor function and normalized Müller glial cell morphology. Single-cell transcriptomics of retinal cells showed that FGF21 receptor Fgfr1 was specifically expressed in Müller glia/astrocytes. Of all retinal cells, FGF21 predominantly affected genes in Müller glia/astrocytes with increased expression of axon development and synapse formation pathway genes. Therefore, enhancing retinal glial axon and synapse formation with neurons may preserve retinal function in RP and may suggest a general therapeutic approach for retinal degenerative diseases.
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Affiliation(s)
- Zhongjie Fu
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA.,The Manton Center for Orphan Disease, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Chenxi Qiu
- Department of Medicine, Division of Translational Therapeutics, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02115, USA
| | - Gael Cagnone
- Department of Pediatrics, Pharmacology and Ophthalmology, CHU Sainte-Justine Research Center, Université de Montréal, Montreal, Qc H3A 0C4, Canada.,Department of Pharmacology and Therapeutics, McGill University, Montreal, Qc H3A 0C4, Canada
| | - Yohei Tomita
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Shuo Huang
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Bertan Cakir
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Yumi Kotoda
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - William Allen
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Edward Bull
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - James D Akula
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Jean-Sébastien Joyal
- Department of Pediatrics, Pharmacology and Ophthalmology, CHU Sainte-Justine Research Center, Université de Montréal, Montreal, Qc H3A 0C4, Canada.,Department of Pharmacology and Therapeutics, McGill University, Montreal, Qc H3A 0C4, Canada
| | - Ann Hellström
- Section for Ophthalmology, Department of Clinical Neuroscience, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Göteborg 405 30, Sweden
| | - Saswata Talukdar
- Cardiometabolic Diseases, Merck Research Laboratories, 33 Avenue Louis Pasteur, Boston, MA 02115, USA
| | - Lois E H Smith
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
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32
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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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33
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Liu G, Chen H, Liu H, Zhang W, Zhou J. Emerging roles of SIRT6 in human diseases and its modulators. Med Res Rev 2021; 41:1089-1137. [PMID: 33325563 PMCID: PMC7906922 DOI: 10.1002/med.21753] [Citation(s) in RCA: 73] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 10/27/2020] [Accepted: 11/01/2020] [Indexed: 12/13/2022]
Abstract
The biological functions of sirtuin 6 (SIRT6; e.g., deacetylation, defatty-acylation, and mono-ADP-ribosylation) play a pivotal role in regulating lifespan and several fundamental processes controlling aging such as DNA repair, gene expression, and telomeric maintenance. Over the past decades, the aberration of SIRT6 has been extensively observed in diverse life-threatening human diseases. In this comprehensive review, we summarize the critical roles of SIRT6 in the onset and progression of human diseases including cancer, inflammation, diabetes, steatohepatitis, arthritis, cardiovascular diseases, neurodegenerative diseases, viral infections, renal and corneal injuries, as well as the elucidation of the related signaling pathways. Moreover, we discuss the advances in the development of small molecule SIRT6 modulators including activators and inhibitors as well as their pharmacological profiles toward potential therapeutics for SIRT6-mediated diseases.
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Affiliation(s)
- Gang Liu
- Chemical Biology Program, Department of Pharmacology and Toxicology, University of Texas Medical Branch, 301 University Blvd., Galveston, TX 77555, USA
| | - Haiying Chen
- Chemical Biology Program, Department of Pharmacology and Toxicology, University of Texas Medical Branch, 301 University Blvd., Galveston, TX 77555, USA
| | - Hua Liu
- Department of Ophthalmology and Visual Sciences, University of Texas Medical Branch, Galveston, TX, 77555, USA
| | - Wenbo Zhang
- Department of Ophthalmology and Visual Sciences, University of Texas Medical Branch, Galveston, TX, 77555, USA
| | - Jia Zhou
- Chemical Biology Program, Department of Pharmacology and Toxicology, University of Texas Medical Branch, 301 University Blvd., Galveston, TX 77555, USA
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34
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Photoreceptor metabolic reprogramming: current understanding and therapeutic implications. Commun Biol 2021; 4:245. [PMID: 33627778 PMCID: PMC7904922 DOI: 10.1038/s42003-021-01765-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Accepted: 01/28/2021] [Indexed: 02/06/2023] Open
Abstract
Acquired and inherited retinal disorders are responsible for vision loss in an increasing proportion of individuals worldwide. Photoreceptor (PR) death is central to the vision loss individuals experience in these various retinal diseases. Unfortunately, there is a lack of treatment options to prevent PR loss, so an urgent unmet need exists for therapies that improve PR survival and ultimately, vision. The retina is one of the most energy demanding tissues in the body, and this is driven in large part by the metabolic needs of PRs. Recent studies suggest that disruption of nutrient availability and regulation of cell metabolism may be a unifying mechanism in PR death. Understanding retinal cell metabolism and how it is altered in disease has been identified as a priority area of research. The focus of this review is on the recent advances in the understanding of PR metabolism and how it is critical to reduction-oxidation (redox) balance, the outer retinal metabolic ecosystem, and retinal disease. The importance of these metabolic processes is just beginning to be realized and unraveling the metabolic and redox pathways integral to PR health may identify novel targets for neuroprotective strategies that prevent blindness in the heterogenous group of retinal disorders.
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Caruso S, Ryu J, Quinn PM, Tsang SH. Precision metabolome reprogramming for imprecision therapeutics in retinitis pigmentosa. J Clin Invest 2021; 130:3971-3973. [PMID: 32657778 DOI: 10.1172/jci139239] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Retinitis pigmentosa (RP), the most common form of rod-cone dystrophy, is caused by greater than 3100 mutations in more than 71 genes, many of which are preferentially expressed in rod photoreceptors. Cone death generally follows rod loss regardless of the underlying pathogenic mutation. Preventing the secondary loss of cone photoreceptors would preserve central visual acuity and substantially improve patients' quality of life. In this issue of the JCI, Wang et al. demonstrate that adeno-associated virus-mediated overexpression of TGF-β1 promoted cone survival and function in 3 distinct RP models with rod-specific mutations. TGF-β1 induces microglia to metabolically tune from a glycolytic phenotype (M1) to an oxidative phenotype (M2), which associates with neuroprotection and the antiinflammatory ecosystem. Consolidating the results of this study with our current understanding of how TGF-β1 regulates microglia polarization, we highlight cell-specific metabolome reprogramming as a promising non-gene-specific therapeutic avenue for inherited retinal degenerations.
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Affiliation(s)
- Salvatore Caruso
- Jonas Children's Vision Care and Bernard and Shirlee Brown Glaucoma Research Laboratory.,Department of Biomedical Engineering, and
| | - Joseph Ryu
- Jonas Children's Vision Care and Bernard and Shirlee Brown Glaucoma Research Laboratory
| | - Peter Mj Quinn
- Jonas Children's Vision Care and Bernard and Shirlee Brown Glaucoma Research Laboratory
| | - Stephen H Tsang
- Jonas Children's Vision Care and Bernard and Shirlee Brown Glaucoma Research Laboratory.,Columbia Stem Cell Initiative.,Department of Ophthalmology.,Department of Pathology.,Department of Cell Biology.,Department of Biomedical Engineering, and.,Institute of Human Nutrition, Vagelos College of Physicians and Surgeons, Columbia University, New York, New York, USA.,Edward S. Harkness Eye Institute, New York-Presbyterian Hospital, New York, New York, USA
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36
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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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Lee SJ, Wang W, Jin L, Lu X, Gao L, Chen Y, Liu T, Emery D, Vukmanic E, Liu Y, Kaplan HJ, Dean DC. Rod photoreceptor clearance due to misfolded rhodopsin is linked to a DAMP-immune checkpoint switch. J Biol Chem 2021; 296:100102. [PMID: 33214223 PMCID: PMC7949052 DOI: 10.1074/jbc.ra120.016053] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 11/13/2020] [Accepted: 11/19/2020] [Indexed: 01/19/2023] Open
Abstract
Chronic endoplasmic reticulum stress resulting from misfolding of the visual pigment rhodopsin (RHO) can lead to loss of rod photoreceptors, which initiates retinitis pigmentosa, characterized initially by diminished nighttime and peripheral vision. Cone photoreceptors depend on rods for glucose transport, which the neurons use for assembly of visual pigment-rich structures; as such, loss of rods also leads to a secondary loss of cone function, diminishing high-resolution color vision utilized for tasks including reading, driving, and facial recognition. If dysfunctional rods could be maintained to continue to serve this secondary cone preservation function, it might benefit patients with retinitis pigmentosa, but the mechanisms by which rods are removed are not fully established. Using pigs expressing mutant RHO, we find that induction of a danger-associated molecular pattern (DAMP) "eat me" signal on the surface of mutant rods is correlated with targeting the live cells for (PrCR) by retinal myeloid cells. Glucocorticoid therapy leads to replacement of this DAMP with a "don't eat me" immune checkpoint on the rod surface and inhibition of PrCR. Surviving rods then continue to promote glucose transport to cones, maintaining their viability.
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Affiliation(s)
- Sang Joon Lee
- Department of Ophthalmology and Visual Sciences, University of Louisville Health Sciences Center, Louisville, Kentucky, USA; Department of Ophthalmology, Kosin University College of Medicine, Seo-gu, Busan, Korea
| | - Wei Wang
- Department of Ophthalmology and Visual Sciences, University of Louisville Health Sciences Center, Louisville, Kentucky, USA
| | - Lei Jin
- Department of Ophthalmology and Visual Sciences, University of Louisville Health Sciences Center, Louisville, Kentucky, USA; Department of Ophthalmology, The Third People's Hospital of Dalian, Dalian Medical University, Dalian, China
| | - Xiaoqin Lu
- Department of Ophthalmology and Visual Sciences, University of Louisville Health Sciences Center, Louisville, Kentucky, USA; Department of Medicine, University of Louisville Health Sciences Center, Louisville, Kentucky, USA
| | - Lei Gao
- Department of Ophthalmology and Visual Sciences, University of Louisville Health Sciences Center, Louisville, Kentucky, USA; Department of Hematology, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Yao Chen
- Department of Ophthalmology and Visual Sciences, University of Louisville Health Sciences Center, Louisville, Kentucky, USA; Department of Ophthalmology, Xiangya Hospital, Central South University, Changsha, China
| | - Tingting Liu
- Department of Ophthalmology and Visual Sciences, University of Louisville Health Sciences Center, Louisville, Kentucky, USA; Department of Ophthalmology, The Third People's Hospital of Dalian, Dalian Medical University, Dalian, China
| | - Douglas Emery
- Department of Ophthalmology and Visual Sciences, University of Louisville Health Sciences Center, Louisville, Kentucky, USA; Department of Medicine, University of Louisville Health Sciences Center, Louisville, Kentucky, USA
| | - Eric Vukmanic
- Department of Ophthalmology and Visual Sciences, University of Louisville Health Sciences Center, Louisville, Kentucky, USA; Department of Medicine, University of Louisville Health Sciences Center, Louisville, Kentucky, USA
| | - Yongqing Liu
- Department of Ophthalmology and Visual Sciences, University of Louisville Health Sciences Center, Louisville, Kentucky, USA; Department of Medicine, University of Louisville Health Sciences Center, Louisville, Kentucky, USA
| | - Henry J Kaplan
- Department of Ophthalmology and Visual Sciences, University of Louisville Health Sciences Center, Louisville, Kentucky, USA
| | - Douglas C Dean
- Department of Ophthalmology and Visual Sciences, University of Louisville Health Sciences Center, Louisville, Kentucky, USA; Department of Medicine, University of Louisville Health Sciences Center, Louisville, Kentucky, USA.
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Metabolic Deregulation of the Blood-Outer Retinal Barrier in Retinitis Pigmentosa. Cell Rep 2020; 28:1323-1334.e4. [PMID: 31365873 PMCID: PMC6693665 DOI: 10.1016/j.celrep.2019.06.093] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Revised: 05/31/2019] [Accepted: 06/26/2019] [Indexed: 02/07/2023] Open
Abstract
Retinitis pigmentosa (RP) initiates with diminished rod photoreceptor function, causing peripheral and nighttime vision loss. However, subsequent loss of cone function and high-resolution daylight and color vision is most debilitating. Visual pigment-rich photoreceptor outer segments (OS) undergo phagocytosis by the retinal pigment epithelium (RPE), and the RPE also acts as a blood-outer retinal barrier transporting nutrients, including glucose, to photoreceptors. We provide evidence that contact between externalized phosphatidylserine (PS) on OS tips and apical RPE receptors activates Akt, linking phagocytosis with glucose transport to photoreceptors for new OS synthesis. As abundant mutant rod OS tips shorten in RP, Akt activation is lost, and onset of glucose metabolism in the RPE and diminished glucose transport combine to cause photoreceptor starvation and accompanying retinal metabolome changes. Subretinal injection of OS tip mimetics displaying PS restores Akt activation, glucose transport, and cone function in end-stage RP after rods are lost. Wang et al. show that onset of glucose metabolism in the retinal pigment epithelium (RPE), which acts as the blood-outer retinal barrier, and inhibition of RPE glucose transport to photoreceptors combine to cause photoreceptor starvation and vision loss in retinitis pigmentosa.
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Ferrara G, Benzi A, Sturla L, Marubbi D, Frumento D, Spinelli S, Abbotto E, Ivaldi F, von Holtey M, Murone M, Nencioni A, Uccelli A, Bruzzone S. Sirt6 inhibition delays the onset of experimental autoimmune encephalomyelitis by reducing dendritic cell migration. J Neuroinflammation 2020; 17:228. [PMID: 32736564 PMCID: PMC7393881 DOI: 10.1186/s12974-020-01906-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Accepted: 07/20/2020] [Indexed: 01/14/2023] Open
Abstract
Background Experimental autoimmune encephalomyelitis (EAE) is the most common animal model of multiple sclerosis (MS), a neuroinflammatory and demyelinating disease characterized by multifocal perivascular infiltrates of immune cells. Although EAE is predominantly considered a T helper 1-driven autoimmune disease, mounting evidence suggests that activated dendritic cells (DC), which are the bridge between innate and adaptive immunity, also contribute to its pathogenesis. Sirtuin 6 (SIRT6), a NAD+-dependent deacetylase involved in genome maintenance and in metabolic homeostasis, regulates DC activation, and its pharmacological inhibition could, therefore, play a role in EAE development. Methods EAE was induced in female C57bl/6 mice by MOG35-55 injection. The effect of treatment with a small compound SIRT6 inhibitor, administered according to therapeutic and preventive protocols, was assessed by evaluating the clinical EAE score. SIRT6 inhibition was confirmed by Western blot analysis by assessing the acetylation of histone 3 lysine 9, a known SIRT6 substrate. The expression of DC activation and migration markers was evaluated by FACS in mouse lymph nodes. In addition, the expression of inflammatory and anti-inflammatory cytokines in the spinal cord were assessed by qPCR. T cell infiltration in spinal cords was evaluated by immunofluorescence imaging. The effect of Sirt6 inhibition on the migration of resting and activated bone marrow-derived dendritic cells was investigated in in vitro chemotaxis assays. Results Preventive pharmacological Sirt6 inhibition effectively delayed EAE disease onset through a novel regulatory mechanism, i.e., by reducing the representation of CXCR4-positive and of CXCR4/CCR7-double-positive DC in lymph nodes. The delay in EAE onset correlated with the early downregulation in the expression of CD40 on activated lymph node DC, with increased level of the anti-inflammatory cytokine IL-10, and with a reduced encephalitogenic T cell infiltration in the central nervous system. Consistent with the in vivo data, in vitro pharmacological Sirt6 inhibition in LPS-stimulated, bone marrow-derived DC reduced CCL19/CCL21- and SDF-1-induced DC migration. Conclusions Our findings indicate the ability of Sirt6 inhibition to impair DC migration, to downregulate pathogenic T cell inflammatory responses and to delay EAE onset. Therefore, Sirt6 might represent a valuable target for developing novel therapeutic agents for the treatment of early stages of MS, or of other autoimmune disorders.
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Affiliation(s)
- Giovanni Ferrara
- Ospedale Policlinico San Martino, IRCCS, Largo R. Benzi, 10, 16132, Genova, Italy.
| | - Andrea Benzi
- Department of Experimental Medicine (DIMES), University of Genova, Genova, Italy
| | - Laura Sturla
- Department of Experimental Medicine (DIMES), University of Genova, Genova, Italy
| | - Daniela Marubbi
- Ospedale Policlinico San Martino, IRCCS, Largo R. Benzi, 10, 16132, Genova, Italy.,Department of Experimental Medicine (DIMES), University of Genova, Genova, Italy
| | - Davide Frumento
- Department of Experimental Medicine (DIMES), University of Genova, Genova, Italy
| | - Sonia Spinelli
- Department of Experimental Medicine (DIMES), University of Genova, Genova, Italy
| | - Elena Abbotto
- Department of Experimental Medicine (DIMES), University of Genova, Genova, Italy
| | - Federico Ivaldi
- Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health (DINOGMI), University of Genova, Genova, Italy
| | | | | | - Alessio Nencioni
- Ospedale Policlinico San Martino, IRCCS, Largo R. Benzi, 10, 16132, Genova, Italy.,Department of Internal Medicine and Medical Specialties (DIMI), University of Genova, Genova, Italy
| | - Antonio Uccelli
- Ospedale Policlinico San Martino, IRCCS, Largo R. Benzi, 10, 16132, Genova, Italy.,Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health (DINOGMI), University of Genova, Genova, Italy
| | - Santina Bruzzone
- Department of Experimental Medicine (DIMES), University of Genova, Genova, Italy
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Weh E, Lutrzykowska Z, Smith A, Hager H, Pawar M, Wubben TJ, Besirli CG. Hexokinase 2 is dispensable for photoreceptor development but is required for survival during aging and outer retinal stress. Cell Death Dis 2020; 11:422. [PMID: 32499533 PMCID: PMC7272456 DOI: 10.1038/s41419-020-2638-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 05/15/2020] [Accepted: 05/18/2020] [Indexed: 02/06/2023]
Abstract
Photoreceptor death is the ultimate cause of vision loss in many retinal degenerative conditions. Identifying novel therapeutic avenues for prolonging photoreceptor health and function has the potential to improve vision and quality of life for patients suffering from degenerative retinal disorders. Photoreceptors are metabolically unique among other neurons in that they process the majority of their glucose via aerobic glycolysis. One of the main regulators of aerobic glycolysis is hexokinase 2 (HK2). Beyond its enzymatic function of phosphorylating glucose to glucose-6-phosphate, HK2 has additional non-enzymatic roles, including the regulation of apoptotic signaling via AKT signaling. Determining the role of HK2 in photoreceptor homeostasis may identify novel signaling pathways that can be targeted with neuroprotective agents to boost photoreceptor survival during metabolic stress. Here we show that following experimental retinal detachment, p-AKT is upregulated and HK2 translocates to mitochondria. Inhibition of AKT phosphorylation in 661W photoreceptor-like cells results in translocation of mitochondrial HK2 to the cytoplasm, increased caspase activity, and decreased cell viability. Rod-photoreceptors lacking HK2 upregulate HK1 and appear to develop normally. Interestingly, we found that HK2-deficient photoreceptors are more susceptible to acute nutrient deprivation in the experimental retinal detachment model. Additionally, HK2 appears to be important for preserving photoreceptors during aging. We show that retinal glucose metabolism is largely unchanged after HK2 deletion, suggesting that the non-enzymatic role of HK2 is important for maintaining photoreceptor health. These results suggest that HK2 expression is critical for preserving photoreceptors during acute nutrient stress and aging. More specifically, p-AKT mediated translocation of HK2 to the mitochondrial surface may be critical for protecting photoreceptors from acute and chronic stress.
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Affiliation(s)
- Eric Weh
- Department of Ophthalmology and Visual Sciences, University of Michigan, 1000 Wall St., Ann Arbor, MI, 48105, US
| | | | - Andrew Smith
- Department of Ophthalmology and Visual Sciences, University of Michigan, 1000 Wall St., Ann Arbor, MI, 48105, US
| | - Heather Hager
- Department of Ophthalmology and Visual Sciences, University of Michigan, 1000 Wall St., Ann Arbor, MI, 48105, US
| | - Mercy Pawar
- Department of Ophthalmology and Visual Sciences, University of Michigan, 1000 Wall St., Ann Arbor, MI, 48105, US
| | - Thomas J Wubben
- Department of Ophthalmology and Visual Sciences, University of Michigan, 1000 Wall St., Ann Arbor, MI, 48105, US
| | - Cagri G Besirli
- Department of Ophthalmology and Visual Sciences, University of Michigan, 1000 Wall St., Ann Arbor, MI, 48105, US.
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41
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Zhang L, Cui X, Han Y, Park KS, Gao X, Zhang X, Yuan Z, Hu Y, Hsu CW, Li X, Bassuk AG, Mahajan VB, Wang NK, Tsang SH. Hypoxic drive caused type 3 neovascularization in a preclinical model of exudative age-related macular degeneration. Hum Mol Genet 2020; 28:3475-3485. [PMID: 31518400 DOI: 10.1093/hmg/ddz159] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 03/29/2019] [Accepted: 07/01/2019] [Indexed: 01/27/2023] Open
Abstract
Hypoxia associated with the high metabolic demand of rods has been implicated in the pathology of age-related macular degeneration (AMD), the most common cause of adult blindness in the developed world. The majority of AMD-associated severe vision loss cases are due to exudative AMD, characterized by neovascularization. To further investigate the causes and histopathology of exudative AMD, we conditionally induced hypoxia in a novel preclinical AMD model (Pde6gcreERT2/+;Vhl-/-) by targeting Vhl and used multimodal imaging and immunohistochemistry to track the development of hypoxia-induced neovascularization. In addition to developing a preclinical model that phenocopies exudative AMD, our studies revealed that the photoreceptor hypoxic response initiates and drives type 3 neovascularization, mainly in the outer retina. Activation of the VHL-HIF1a-VEGF-EPO pathway in the adult retina led to long-term neovascularization, retinal hemorrhages and compromised retinal layers. Our novel preclinical model would accelerate the testing of therapies that use metabolomic approaches to ameliorate AMD.
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Affiliation(s)
- Lijuan Zhang
- Shanxi Eye Hospital, affiliated with Shanxi Medical University. Fudong St. 100, Xinghualing, Taiyuan, Shanxi 030002, China
| | - Xuan Cui
- Tianjin Medical University Eye Hospital, Tianjin Medical University Eye Institute & Tianjin Medical University School of Optometry and Ophthalmology, Tianjin 300384, China, New York, NY10032, USA.,Jonas Children's Vision Care and the Bernard & Shirlee Brown Glaucoma Laboratory, Herbert Irving Comprehensive Cancer Center, New York, NY 10032, USA.,Edward S. Harkness Eye Institute, New York-Presbyterian Hospital, New York, NY 10032, USA
| | - Yangjun Han
- Shanxi Cardiovascular Disease Hospital, Yifen street 18, Wanbailin, Taiyuan, Shanxi 030024, China
| | - Karen Sophia Park
- Jonas Children's Vision Care and the Bernard & Shirlee Brown Glaucoma Laboratory, Herbert Irving Comprehensive Cancer Center, New York, NY 10032, USA.,Edward S. Harkness Eye Institute, New York-Presbyterian Hospital, New York, NY 10032, USA
| | - Xiaohong Gao
- Shanxi Eye Hospital, affiliated with Shanxi Medical University. Fudong St. 100, Xinghualing, Taiyuan, Shanxi 030002, China
| | - Ximei Zhang
- Shanxi Eye Hospital, affiliated with Shanxi Medical University. Fudong St. 100, Xinghualing, Taiyuan, Shanxi 030002, China
| | - Zhigang Yuan
- Shanxi Eye Hospital, affiliated with Shanxi Medical University. Fudong St. 100, Xinghualing, Taiyuan, Shanxi 030002, China
| | - Yong Hu
- Department of Neurology, Shanghai Tongji Hospital, Tongji University School of Medicine, Shanghai 200092, China
| | - Chun-Wei Hsu
- Jonas Children's Vision Care and the Bernard & Shirlee Brown Glaucoma Laboratory, Herbert Irving Comprehensive Cancer Center, New York, NY 10032, USA.,Edward S. Harkness Eye Institute, New York-Presbyterian Hospital, New York, NY 10032, USA
| | - Xiaorong Li
- Tianjin Medical University Eye Hospital, Tianjin Medical University Eye Institute & Tianjin Medical University School of Optometry and Ophthalmology, Tianjin 300384, China, New York, NY10032, USA
| | | | - Vinit B Mahajan
- Byers Eye Institute, Omics Laboratory, Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA 94303, USA.,Veterans Affairs Palo Alto Health Care System, Palo Alto, CA 94304, USA
| | - Nan-Kai Wang
- Jonas Children's Vision Care and the Bernard & Shirlee Brown Glaucoma Laboratory, Herbert Irving Comprehensive Cancer Center, New York, NY 10032, USA.,Edward S. Harkness Eye Institute, New York-Presbyterian Hospital, New York, NY 10032, USA
| | - Stephen H Tsang
- Jonas Children's Vision Care and the Bernard & Shirlee Brown Glaucoma Laboratory, Herbert Irving Comprehensive Cancer Center, New York, NY 10032, USA.,Edward S. Harkness Eye Institute, New York-Presbyterian Hospital, New York, NY 10032, USA.,Department of Pathology & Cell Biology, Stem Cell Initiative (CSCI), Institute of Human Nutrition, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
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42
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Rajala RVS. Aerobic Glycolysis in the Retina: Functional Roles of Pyruvate Kinase Isoforms. Front Cell Dev Biol 2020; 8:266. [PMID: 32426353 PMCID: PMC7203425 DOI: 10.3389/fcell.2020.00266] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Accepted: 03/30/2020] [Indexed: 12/28/2022] Open
Abstract
One hundred years ago, Otto Heinrich Warburg observed that postmitotic retinal cells are the highest oxygen-consuming cells in the body. He compared these cells to actively growing mitotic tumor cells since both cells reprogram glucose for anabolic processes, which include lipid, protein, and RNA/DNA synthesis, and for antioxidant metabolism. To achieve this metabolic reprogramming, cancer cells preferentially express a less active dimeric form, the M2 isoform of pyruvate kinase (PKM2), which shuttles glucose toward the accumulation of glycolytic intermediates that redirect cell activities into anabolic processes. Similar to cancer cells, retinal photoreceptors predominantly express the M2 isoform of PKM2. This isoform performs both metabolic and non-metabolic functions in photoreceptor cells. This review focuses on the metabolic and non-metabolic roles of pyruvate kinases in photoreceptor cell functions.
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Affiliation(s)
- Raju V S Rajala
- Department of Ophthalmology, The University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States.,Department of Physiology, The University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States.,Department of Cell Biology, The University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States.,Dean McGee Eye Institute, Oklahoma City, OK, United States
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Zhang E, Ryu J, Levi SR, Oh JK, Hsu CW, Cui X, Lee TT, Wang NK, Lima de Carvalho JR, Tsang SH. PKM2 ablation enhanced retinal function and survival in a preclinical model of retinitis pigmentosa. Mamm Genome 2020; 31:77-85. [PMID: 32342224 DOI: 10.1007/s00335-020-09837-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Accepted: 04/08/2020] [Indexed: 12/13/2022]
Abstract
Retinitis pigmentosa (RP) is a neurodegenerative disorder that causes irreversible vision loss in over 1.5 million individuals world-wide. The genetic heterogeneity of RP necessitates a broad therapy that is able to provide treatment in a gene- and mutation- non-specific manner. In this study, we identify the therapeutic benefits of metabolic reprogramming by targeting pyruvate kinase M2 (PKM2) in a Pde6β preclinical model of RP. The genetic contributions of PKM2 inhibition in retinal degeneration were evaluated through histology and electroretinogram (ERG) followed by a statistical analysis using a linear regression model. Notably, PKM2 ablation resulted in thicker retinal layers in Pde6β-mutated mice as compared to the controls, suggesting greater photoreceptor survival. Consistent with these anatomical findings, ERG analyses revealed that the maximum b-wave is on average greater in Pkm2 knockout mice than in mice with intact Pkm2, indicating enhanced photoreceptor function. These rescue phenotypes from Pkm2 ablation in a preclinical model of RP indicate that a metabolome reprogramming may be useful in treating RP.
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Affiliation(s)
- Ethan Zhang
- Jonas Children's Vision Care and Bernard & Shirlee Brown Glaucoma Laboratory, Edward S. Harkness Eye Institute, New York-Presbyterian Hospital, New York, NY, USA
| | - Joseph Ryu
- Jonas Children's Vision Care and Bernard & Shirlee Brown Glaucoma Laboratory, Edward S. Harkness Eye Institute, New York-Presbyterian Hospital, New York, NY, USA
| | - Sarah R Levi
- Jonas Children's Vision Care and Bernard & Shirlee Brown Glaucoma Laboratory, Edward S. Harkness Eye Institute, New York-Presbyterian Hospital, New York, NY, USA
| | - Jin Kyun Oh
- Jonas Children's Vision Care and Bernard & Shirlee Brown Glaucoma Laboratory, Edward S. Harkness Eye Institute, New York-Presbyterian Hospital, New York, NY, USA
- State University of New York At Downstate Medical Center, Brooklyn, NY, USA
| | - Chun Wei Hsu
- Jonas Children's Vision Care and Bernard & Shirlee Brown Glaucoma Laboratory, Edward S. Harkness Eye Institute, New York-Presbyterian Hospital, New York, NY, USA
| | - Xuan Cui
- Jonas Children's Vision Care and Bernard & Shirlee Brown Glaucoma Laboratory, Edward S. Harkness Eye Institute, New York-Presbyterian Hospital, New York, NY, USA
- The College of Optometry, Tianjin Medical University Eye Hospital, Tianjin Medical University Eye Institute, Tianjin, China
| | - Ting-Ting Lee
- Department of Genetics, Stanford University, Stanford, CA, USA
| | - Nan-Kai Wang
- Jonas Children's Vision Care and Bernard & Shirlee Brown Glaucoma Laboratory, Edward S. Harkness Eye Institute, New York-Presbyterian Hospital, New York, NY, USA
- College of Medicine, Chang Gung University, Taoyuan, Taiwan
- Department of Ophthalmology, Chang Gung Memorial Hospital, Linkou Medical Center, Taoyuan, Taiwan
| | - Jose Ronaldo Lima de Carvalho
- Jonas Children's Vision Care and Bernard & Shirlee Brown Glaucoma Laboratory, Edward S. Harkness Eye Institute, New York-Presbyterian Hospital, New York, NY, USA
- Department of Ophthalmology, Empresa Brasileira de Servicos Hospitalares (EBSERH) - Hospital das Clinicas de Pernambuco (HCPE), Federal University of Pernambuco (UFPE), Recife, Brazil
- Department of Ophthalmology, Federal University of Sao Paulo, Sao Paulo, Brazil
| | - Stephen H Tsang
- Jonas Children's Vision Care and Bernard & Shirlee Brown Glaucoma Laboratory, Edward S. Harkness Eye Institute, New York-Presbyterian Hospital, New York, NY, USA.
- Department of Pathology & Cell Biology, Institute of Human Nutrition, and Columbia Stem Cell Initiative, Columbia University, New York, NY, USA.
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Metabolic and Redox Signaling of the Nucleoredoxin-Like-1 Gene for the Treatment of Genetic Retinal Diseases. Int J Mol Sci 2020; 21:ijms21051625. [PMID: 32120883 PMCID: PMC7084304 DOI: 10.3390/ijms21051625] [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: 01/31/2020] [Revised: 02/24/2020] [Accepted: 02/26/2020] [Indexed: 02/06/2023] Open
Abstract
The loss of cone photoreceptor function in retinitis pigmentosa (RP) severely impacts the central and daily vision and quality of life of patients affected by this disease. The loss of cones follows the degeneration of rods, in a manner independent of the causing mutations in numerous genes associated with RP. We have explored this phenomenon and proposed that the loss of rods triggers a reduction in the expression of rod-derived cone viability factor (RdCVF) encoded by the nucleoredoxin-like 1 (NXNL1) gene which interrupts the metabolic and redox signaling between rods and cones. After providing scientific evidence supporting this mechanism, we propose a way to restore this lost signaling and prevent the cone vision loss in animal models of RP. We also explain how we could restore this signaling to prevent cone vision loss in animal models of the disease and how we plan to apply this therapeutic strategy by the administration of both products of NXNL1 encoding the trophic factor RdCVF and the thioredoxin enzyme RdCVFL using an adeno-associated viral vector. We describe in detail all the steps of this translational program, from the design of the drug, its production, biological validation, and analytical and preclinical qualification required for a future clinical trial that would, if successful, provide a treatment for this incurable disease.
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Hurley JB, Chao JR. Retinal disease: How to use proteomics to speed up diagnosis and metabolomics to slow down degeneration. EBioMedicine 2020; 53:102687. [PMID: 32113163 PMCID: PMC7047175 DOI: 10.1016/j.ebiom.2020.102687] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Revised: 02/09/2020] [Accepted: 02/09/2020] [Indexed: 01/07/2023] Open
Affiliation(s)
- James B Hurley
- Department of Biochemistry, University of Washington, Seattle, WA 98195, United States; Department of Ophthalmology, University of Washington, Seattle, WA 98109, United States.
| | - Jennifer R Chao
- Department of Ophthalmology, University of Washington, Seattle, WA 98109, United States
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Wubben TJ, Pawar M, Weh E, Smith A, Sajjakulnukit P, Zhang L, Dai L, Hager H, Pai MP, Lyssiotis CA, Besirli CG. Small molecule activation of metabolic enzyme pyruvate kinase muscle isozyme 2, PKM2, circumvents photoreceptor apoptosis. Sci Rep 2020; 10:2990. [PMID: 32076076 PMCID: PMC7031539 DOI: 10.1038/s41598-020-59999-w] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Accepted: 02/06/2020] [Indexed: 01/22/2023] Open
Abstract
Photoreceptor cell death is the ultimate cause of vision loss in many retinal disorders, and there is an unmet need for neuroprotective modalities to improve photoreceptor survival. Similar to cancer cells, photoreceptors maintain pyruvate kinase muscle isoform 2 (PKM2) expression, which is a critical regulator in aerobic glycolysis. Unlike PKM1, which has constitutively high catalytic activity, PKM2 is under complex regulation. Recently, we demonstrated that genetically reprogramming photoreceptor metabolism via PKM2-to-PKM1 substitution is a promising neuroprotective strategy. Here, we explored the neuroprotective effects of pharmacologically activating PKM2 via ML-265, a small molecule activator of PKM2, during acute outer retinal stress. We found that ML-265 increased PKM2 activity in 661 W cells and in vivo in rat eyes without affecting the expression of genes involved in glucose metabolism. ML-265 treatment did, however, alter metabolic intermediates of glucose metabolism and those necessary for biosynthesis in cultured cells. Long-term exposure to ML-265 did not result in decreased photoreceptor function or survival under baseline conditions. Notably, though, ML-265-treatment did reduce entrance into the apoptotic cascade in in vitro and in vivo models of outer retinal stress. These data suggest that reprogramming metabolism via activation of PKM2 is a novel, and promising, therapeutic strategy for photoreceptor neuroprotection.
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Affiliation(s)
- Thomas J Wubben
- University of Michigan, Kellogg Eye Center, Department of Ophthalmology and Visual Sciences, Ann Arbor, USA
| | - Mercy Pawar
- University of Michigan, Kellogg Eye Center, Department of Ophthalmology and Visual Sciences, Ann Arbor, USA
| | - Eric Weh
- University of Michigan, Kellogg Eye Center, Department of Ophthalmology and Visual Sciences, Ann Arbor, USA
| | - Andrew Smith
- University of Michigan, Kellogg Eye Center, Department of Ophthalmology and Visual Sciences, Ann Arbor, USA
| | - Peter Sajjakulnukit
- University of Michigan, Department of Molecular and Integrative Physiology, Ann Arbor, USA
| | - Li Zhang
- University of Michigan Biomedical Research Core Facilities, Metabolomics Core, Ann Arbor, USA
| | - Lipeng Dai
- University of Michigan, College of Pharmacy, Ann Arbor, USA
| | - Heather Hager
- University of Michigan, Kellogg Eye Center, Department of Ophthalmology and Visual Sciences, Ann Arbor, USA
| | | | - Costas A Lyssiotis
- University of Michigan, Department of Molecular and Integrative Physiology, Ann Arbor, USA
| | - Cagri G Besirli
- University of Michigan, Kellogg Eye Center, Department of Ophthalmology and Visual Sciences, Ann Arbor, USA.
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MacDonald IM, Moen C, Duncan JL, Tsang SH, Cehajic-Kapetanovic J, Aleman TS. Perspectives on Gene Therapy: Choroideremia Represents a Challenging Model for the Treatment of Other Inherited Retinal Degenerations. Transl Vis Sci Technol 2020; 9:17. [PMID: 32714643 PMCID: PMC7351877 DOI: 10.1167/tvst.9.3.17] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Purpose To report combined viewpoints on ocular gene therapy from a select group of clinician scientists and a patient advocacy group. Methods With the support of Randy Wheelock and Dr. Chris Moen from the Choroideremia Research Foundation (CRF), a special interest group at the 2019 Annual meeting of the Association for Research in Vision and Ophthalmology in Vancouver, Canada, shared their knowledge, experience, concepts, and ideas and provided a forum to discuss therapeutic strategies for the treatment of inherited retinal disorders, using experience in choroideremia (CHM) as a model. Results A member of the CRF presented the patient perspective and role in clinical trials. Five clinician scientists presented reasons for limited long-term visual improvement in many gene therapy trials, including challenges with dose, incomplete understanding of photoreceptor metabolism, vector delivery, inflammation, and identification of patients likely to benefit from treatment. Conclusions The shared experience of the five clinician scientists indicates that the results of ocular gene therapy for choroideremia have been less successful than for RPE65-related Leber congenital amaurosis. Improvement in vector delivery and developing a better understanding of gene expression in target tissues, treatment dose and side effects, and inflammation, as well as identifying patients who are most likely to benefit without suffering excessive risk, are necessary to advance the development of effective therapies for inherited retinal degenerations. Translational Relevance Additional long-term data are required to determine if ocular gene therapy will be sufficient to alter natural progression in choroideremia. Combination therapies may have to be considered, as well as alternative vectors that minimize risk.
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Affiliation(s)
- Ian M. MacDonald
- Department of Ophthalmology and Visual Sciences, University of Alberta, Edmonton, Canada
| | | | - Jacque L. Duncan
- Department of Ophthalmology, University of California, San Francisco, San Francisco, CA, USA
| | - Stephen H. Tsang
- Jonas Children's Vision Care, Columbia Stem Cell Initiative, Departments of Ophthalmology, Pathology, and Cell Biology, Institute of Human Nutrition, Vagelos College of Physicians and Surgeons, Columbia University,New York, NY, USA
- Edward S. Harkness Eye Institute, New York–Presbyterian Hospital, New York, NY, USA
| | | | - Tomas S. Aleman
- Center for Advanced Research and Ocular Therapeutics, Scheie Eye Institute at the Perelman Center for Advanced Medicine, Department of Ophthalmology, University of Pennsylvania, Philadelphia, PA, 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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Brown EE, Lewin AS, Ash JD. AMPK May Play an Important Role in the Retinal Metabolic Ecosystem. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1185:477-481. [PMID: 31884657 DOI: 10.1007/978-3-030-27378-1_78] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Evidence suggests that metabolic dysregulation plays an important role in disease etiology of retinal degenerations. Several studies suggest that preserving the retinal metabolic ecosystem may be protective against retinal degenerations. We investigated whether activation of 5' adenosine monophosphate protein kinase (AMPK) is protective to the retina in several preclinical mouse models of retinal degeneration and found that metformin-induced activation of AMPK was able to delay or prevent retinal degeneration in the rd10 model of retinitis pigmentosa, the NaIO3 model of RPE and retinal injury, and the light damage model of retinal degeneration. This protection was associated with increased mitochondrial DNA copy number, increased levels of ATP, and a reduction in oxidative stress and oxidative DNA damage. We propose that AMPK plays an important role in regulation of the retinal metabolic ecosystem and that activation of AMPK may promote metabolic processes to prevent retinal degeneration.
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Affiliation(s)
- Emily E Brown
- Departments of Ophthalmology, Clinical and Translational Science Institute, Gainesville, FL, USA
| | - Alfred S Lewin
- Molecular Genetics and Microbiology, University of Florida College of Medicine, Gainesville, FL, USA
| | - John D Ash
- Departments of Ophthalmology, Clinical and Translational Science Institute, Gainesville, FL, USA.
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Petit L, Ma S, Cipi J, Cheng SY, Zieger M, Hay N, Punzo C. Aerobic Glycolysis Is Essential for Normal Rod Function and Controls Secondary Cone Death in Retinitis Pigmentosa. Cell Rep 2019; 23:2629-2642. [PMID: 29847794 PMCID: PMC5997286 DOI: 10.1016/j.celrep.2018.04.111] [Citation(s) in RCA: 72] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Revised: 03/22/2018] [Accepted: 04/25/2018] [Indexed: 02/06/2023] Open
Abstract
Aerobic glycolysis accounts for ~80%–90% of glucose used by adult photoreceptors (PRs); yet, the importance of aerobic glycolysis for PR function or survival remains unclear. Here, we further established the role of aerobic glycolysis in murine rod and cone PRs. We show that loss of hexokinase-2 (HK2), a key aerobic glycolysis enzyme, does not affect PR survival or structure but is required for normal rod function. Rods with HK2 loss increase their mitochondrial number, suggesting an adaptation to the inhibition of aerobic glycolysis. In contrast, cones adapt without increased mitochondrial number but require HK2 to adapt to metabolic stress conditions such as those encountered in retinitis pigmentosa, where the loss of rods causes a nutrient shortage in cones. The data support a model where aerobic glycolysis in PRs is not a necessity but rather a metabolic choice that maximizes PR function and adaptability to nutrient stress conditions.
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Affiliation(s)
- Lolita Petit
- Department of Ophthalmology and Gene Therapy Center, University of Massachusetts Medical School, Worcester, MA, USA
| | - Shan Ma
- Department of Ophthalmology and Gene Therapy Center, University of Massachusetts Medical School, Worcester, MA, USA
| | - Joris Cipi
- Department of Ophthalmology and Gene Therapy Center, University of Massachusetts Medical School, Worcester, MA, USA
| | - Shun-Yun Cheng
- Department of Ophthalmology and Gene Therapy Center, University of Massachusetts Medical School, Worcester, MA, USA
| | - Marina Zieger
- Division of Pulmonary Medicine, Department of Pediatrics, University of Massachusetts Medical School, Worcester, MA, USA
| | - Nissim Hay
- Department of Biochemistry and Molecular Genetics, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA
| | - Claudio Punzo
- Department of Ophthalmology and Gene Therapy Center, University of Massachusetts Medical School, Worcester, MA, USA.
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