51
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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: 80] [Impact Index Per Article: 16.0] [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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52
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Blond F, Léveillard T. Functional Genomics of the Retina to Elucidate its Construction and Deconstruction. Int J Mol Sci 2019; 20:E4922. [PMID: 31590277 PMCID: PMC6801968 DOI: 10.3390/ijms20194922] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Accepted: 10/01/2019] [Indexed: 12/20/2022] Open
Abstract
The retina is the light sensitive part of the eye and nervous tissue that have been used extensively to characterize the function of the central nervous system. The retina has a central position both in fundamental biology and in the physiopathology of neurodegenerative diseases. We address the contribution of functional genomics to the understanding of retinal biology by reviewing key events in their historical perspective as an introduction to major findings that were obtained through the study of the retina using genomics, transcriptomics and proteomics. We illustrate our purpose by showing that most of the genes of interest for retinal development and those involved in inherited retinal degenerations have a restricted expression to the retina and most particularly to photoreceptors cells. We show that the exponential growth of data generated by functional genomics is a future challenge not only in terms of storage but also in terms of accessibility to the scientific community of retinal biologists in the future. Finally, we emphasize on novel perspectives that emerge from the development of redox-proteomics, the new frontier in retinal biology.
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Affiliation(s)
- Frédéric Blond
- Department of Genetics, Sorbonne Université, INSERM, CNRS, Institut de la Vision, 17 rue Moreau, F-75012 Paris, France.
| | - Thierry Léveillard
- Department of Genetics, Sorbonne Université, INSERM, CNRS, Institut de la Vision, 17 rue Moreau, F-75012 Paris, France.
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53
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Park KS, Lima de Carvalho JR, Tsang SH. Sustained Rescue of Rod Function and Probable Non-Cell-Autonomous Rescue of Cones after Gene Therapy. Ophthalmology 2019; 126:1286-1287. [PMID: 31443790 PMCID: PMC9121307 DOI: 10.1016/j.ophtha.2019.03.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Revised: 03/06/2019] [Accepted: 03/08/2019] [Indexed: 10/26/2022] Open
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54
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Wang NK, Mahajan VB, Tsang SH. Therapeutic Window for Phosphodiesterase 6-Related Retinitis Pigmentosa. JAMA Ophthalmol 2019; 137:679-680. [PMID: 30998807 PMCID: PMC10914386 DOI: 10.1001/jamaophthalmol.2018.6381] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
- Nan-Kai Wang
- Jonas Children's Vision Care and Bernard & Shirlee Brown Glaucoma Laboratory, Departments of Ophthalmology and Pathology and Cell Biology, Columbia Stem Cell Initiative, Institute of Human Nutrition, Herbert Irving Comprehensive Cancer Center, Columbia University, New York, New York
- Electrodiagnostic Services, New York-Presbyterian Hospital, New York
| | - Vinit B Mahajan
- Department of Ophthalmology, Byers Eye Institute, Stanford University, Palo Alto, California
- Palo Alto Veterans Administration, Palo Alto, California
- Omics Laboratory, Stanford University, Palo Alto, California
- Byers Eye Institute, Department of Ophthalmology, Stanford University, Palo Alto, California
- Department of Neurology, University of Iowa, Iowa City
| | - Stephen H Tsang
- Jonas Children's Vision Care and Bernard & Shirlee Brown Glaucoma Laboratory, Departments of Ophthalmology and Pathology and Cell Biology, Columbia Stem Cell Initiative, Institute of Human Nutrition, Herbert Irving Comprehensive Cancer Center, Columbia University, New York, New York
- Electrodiagnostic Services, New York-Presbyterian Hospital, New York
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55
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Brown EE, DeWeerd AJ, Ildefonso CJ, Lewin AS, Ash JD. Mitochondrial oxidative stress in the retinal pigment epithelium (RPE) led to metabolic dysfunction in both the RPE and retinal photoreceptors. Redox Biol 2019; 24:101201. [PMID: 31039480 PMCID: PMC6488819 DOI: 10.1016/j.redox.2019.101201] [Citation(s) in RCA: 126] [Impact Index Per Article: 25.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Revised: 04/10/2019] [Accepted: 04/11/2019] [Indexed: 12/22/2022] Open
Abstract
Age-related macular degeneration (AMD) is the leading cause of vision loss in the western world. Recent evidence suggests that RPE and photoreceptors have an interconnected metabolism and that mitochondrial damage in RPE is a trigger for degeneration in both RPE and photoreceptors in AMD. To test this hypothesis, this study was designed to induce mitochondrial damage in RPE in mice to determine whether this is sufficient to cause RPE and photoreceptor damage characteristic of AMD. In this study, we conditionally deleted the gene encoding the mitochondrial antioxidant enzyme, manganese superoxide dismutase (MnSOD encoded by Sod2) in the retinal pigment epithelium (RPE) of albino BALB/cJ mice. VMD2-Cre;Sod2flox/flox BALB/cJ mice were housed in either 12-h dark, 12-h 200 lux white lighting (normal light), or 12-h dark, 12-h <10 lux red lighting (dim light). Electroretinography (ERG) and spectral-domain optical coherence tomography (SD-OCT) were performed to assess retinal function and morphology. Immunofluorescence was used to examine protein expression; quantitative RT-PCR was used to measure gene expression. Sod2 knockout (KO) mice had reduced RPE function with age and increased oxidative stress compared to wild type (WT) controls as expected by the cell-specific deletion of Sod2. This was associated with alterations in RPE morphology and the structure and function of RPE mitochondria. In addition, data show a compensatory increase in RPE glycolytic metabolism. The metabolic shift in RPE correlated with severe disruption of photoreceptor mitochondria including a reduction in TOMM20 expression, mitochondrial fragmentation, and reduced COXIII/β-actin levels. These findings demonstrate that mitochondrial oxidative stress can lead to RPE dysfunction and metabolic reprogramming of RPE. Secondary to these changes, photoreceptors also undergo metabolic stress with increased mitochondrial damage. These data are consistent with the hypothesis of a linked metabolism between RPE and photoreceptors and suggest a mechanism of retinal degeneration in dry AMD. Deletion of Sod2 in the RPE led to loss of RPE function. Knockout mice had decreased ATP levels and decreased COXIII/β-actin levels in the RPE. Knockout mice had elevated expression of glycolytic enzymes in the RPE. RPE alterations led to secondary effects on photoreceptors.
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Affiliation(s)
- Emily E Brown
- Department of Ophthalmology, College of Medicine, University of Florida, Gainesville, FL, USA; Clinical and Translational Science Institute, University of Florida, Gainesville, FL, USA
| | - Alexander J DeWeerd
- Department of Ophthalmology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Cristhian J Ildefonso
- Department of Ophthalmology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Alfred S Lewin
- Department of Molecular Genetics and Microbiology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - John D Ash
- Department of Ophthalmology, College of Medicine, University of Florida, Gainesville, FL, USA.
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56
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Loss of MPC1 reprograms retinal metabolism to impair visual function. Proc Natl Acad Sci U S A 2019; 116:3530-3535. [PMID: 30808746 DOI: 10.1073/pnas.1812941116] [Citation(s) in RCA: 70] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Glucose metabolism in vertebrate retinas is dominated by aerobic glycolysis (the "Warburg Effect"), which allows only a small fraction of glucose-derived pyruvate to enter mitochondria. Here, we report evidence that the small fraction of pyruvate in photoreceptors that does get oxidized by their mitochondria is required for visual function, photoreceptor structure and viability, normal neuron-glial interaction, and homeostasis of retinal metabolism. The mitochondrial pyruvate carrier (MPC) links glycolysis and mitochondrial metabolism. Retina-specific deletion of MPC1 results in progressive retinal degeneration and decline of visual function in both rod and cone photoreceptors. Using targeted-metabolomics and 13C tracers, we found that MPC1 is required for cytosolic reducing power maintenance, glutamine/glutamate metabolism, and flexibility in fuel utilization.
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57
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Sinha T, Makia M, Du J, Naash MI, Al-Ubaidi MR. Flavin homeostasis in the mouse retina during aging and degeneration. J Nutr Biochem 2018; 62:123-133. [PMID: 30290331 PMCID: PMC7162609 DOI: 10.1016/j.jnutbio.2018.09.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Revised: 07/31/2018] [Accepted: 09/01/2018] [Indexed: 12/14/2022]
Abstract
Involvement of flavin adenine dinucleotide (FAD) and flavin mononucleotide (FMN) in cellular homeostasis has been well established for tissues other than the retina. Here, we present an optimized method to effectively extract and quantify FAD and FMN from a single neural retina and its corresponding retinal pigment epithelium (RPE). Optimizations led to detection efficiency of 0.1 pmol for FAD and FMN while 0.01 pmol for riboflavin. Interestingly, levels of FAD and FMN in the RPE were found to be 1.7- and 12.5-fold higher than their levels in the retina, respectively. Both FAD and FMN levels in the RPE and retina gradually decline with age and preceded the age-dependent drop in the functional competence of the retina as measured by electroretinography. Further, quantifications of retinal levels of FAD and FMN in different mouse models of retinal degeneration revealed differential metabolic requirements of these two factors in relation to the rate and degree of photoreceptor degeneration. We also found twofold reductions in retinal levels of FAD and FMN in two mouse models of diabetic retinopathy. Altogether, our results suggest that retinal levels of FAD and FMN can be used as potential markers to determine state of health of the retina in general and more specifically the photoreceptors.
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Affiliation(s)
- Tirthankar Sinha
- Department of Biomedical Engineering, University of Houston, Houston, TX 77204
| | - Mustafa Makia
- Department of Biomedical Engineering, University of Houston, Houston, TX 77204
| | - Jianhai Du
- Department of Ophthalmology and Department of Biochemistry, West Virginia University, Morgantown, WV 26506
| | - Muna I Naash
- Department of Biomedical Engineering, University of Houston, Houston, TX 77204.
| | - Muayyad R Al-Ubaidi
- Department of Biomedical Engineering, University of Houston, Houston, TX 77204.
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58
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Nicotine promotes neuron survival and partially protects from Parkinson's disease by suppressing SIRT6. Acta Neuropathol Commun 2018; 6:120. [PMID: 30409187 PMCID: PMC6223043 DOI: 10.1186/s40478-018-0625-y] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Accepted: 10/28/2018] [Indexed: 12/27/2022] Open
Abstract
Parkinson’s disease is characterized by progressive death of dopaminergic neurons, leading to motor and cognitive dysfunction. Epidemiological studies consistently show that the use of tobacco reduces the risk of Parkinson’s. We report that nicotine reduces the abundance of SIRT6 in neuronal culture and brain tissue. We find that reduction of SIRT6 is partly responsible for neuroprotection afforded by nicotine. Additionally, SIRT6 abundance is greater in Parkinson’s patient brains, and decreased in the brains of tobacco users. We also identify SNPs that promote SIRT6 expression and simultaneously associate with an increased risk of Parkinson’s. Furthermore, brain-specific SIRT6 knockout mice are protected from MPTP-induced Parkinson’s, while SIRT6 overexpressing mice develop more severe pathology. Our data suggest that SIRT6 plays a pathogenic and pro-inflammatory role in Parkinson’s and that nicotine can provide neuroprotection by accelerating its degradation. Inhibition of SIRT6 may be a promising strategy to ameliorate Parkinson’s and neurodegeneration.
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59
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Lin JB, Apte RS. NAD + and sirtuins in retinal degenerative diseases: A look at future therapies. Prog Retin Eye Res 2018; 67:118-129. [PMID: 29906612 PMCID: PMC6235699 DOI: 10.1016/j.preteyeres.2018.06.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Revised: 06/08/2018] [Accepted: 06/11/2018] [Indexed: 12/19/2022]
Abstract
Retinal degenerative diseases are a major cause of morbidity in modern society because visual impairment significantly decreases the quality of life of patients. A significant challenge in treating retinal degenerative diseases is their genetic and phenotypic heterogeneity. However, despite this diversity, many of these diseases share a common endpoint involving death of light-sensitive photoreceptors. Identifying common pathogenic mechanisms that contribute to photoreceptor death in these diverse diseases may lead to a unifying therapy for multiple retinal diseases that would be highly innovative and address a great clinical need. Because the retina and photoreceptors, in particular, have immense metabolic and energetic requirements, many investigators have hypothesized that metabolic dysfunction may be a common link unifying various retinal degenerative diseases. Here, we discuss a new area of research examining the role of NAD+ and sirtuins in regulating retinal metabolism and in the pathogenesis of retinal degenerative diseases. Indeed, the results of numerous studies suggest that NAD+ intermediates or small molecules that modulate sirtuin function could enhance retinal metabolism, reduce photoreceptor death, and improve vision. Although further research is necessary to translate these findings to the bedside, they have strong potential to truly transform the standard of care for patients with retinal degenerative diseases.
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Affiliation(s)
- Jonathan B Lin
- Department of Ophthalmology & Visual Sciences, Washington University School of Medicine, St. Louis, MO, USA; Neuroscience Graduate Program, Division of Biology and Biomedical Sciences, Washington University School of Medicine, St. Louis, MO, USA
| | - Rajendra S Apte
- Department of Ophthalmology & Visual Sciences, Washington University School of Medicine, St. Louis, MO, USA; Neuroscience Graduate Program, Division of Biology and Biomedical Sciences, Washington University School of Medicine, St. Louis, MO, USA; Department of Medicine, Washington University School of Medicine, St. Louis, MO, USA; Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO, USA.
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60
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Stimulation of AMPK prevents degeneration of photoreceptors and the retinal pigment epithelium. Proc Natl Acad Sci U S A 2018; 115:10475-10480. [PMID: 30249643 DOI: 10.1073/pnas.1802724115] [Citation(s) in RCA: 104] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Retinal degenerative diseases are generally characterized by a permanent loss of light-sensitive retinal neurons known as photoreceptors, or their support cells, the retinal pigmented epithelium (RPE). Metabolic dysfunction has been implicated as a common mechanism of degeneration. In this study, we used the drug metformin in a gain-of-function approach to activate adenosine monophosphate-activated protein kinase (AMPK). We found that treatment protected photoreceptors and the RPE from acute injury and delayed inherited retinal degeneration. Protection was associated with decreased oxidative stress, decreased DNA damage, and increased mitochondrial energy production. To determine whether protection was a local or a systemic effect of metformin, we used AMPK retinal knockout mice and found that local expression of AMPK catalytic subunit α2 was required for metformin-induced protection. Our data demonstrate that increasing the activity of AMPK in retinal neurons or glia can delay or prevent degeneration of photoreceptors and the RPE from multiple types of cell-death triggers.
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61
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Rajala A, Wang Y, Soni K, Rajala RVS. Pyruvate kinase M2 isoform deletion in cone photoreceptors results in age-related cone degeneration. Cell Death Dis 2018; 9:737. [PMID: 29970877 PMCID: PMC6030055 DOI: 10.1038/s41419-018-0712-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Revised: 05/13/2018] [Accepted: 05/16/2018] [Indexed: 12/11/2022]
Abstract
The tumor form of pyruvate kinase M2 has been suggested to promote cellular anabolism by redirecting the metabolism to cause accumulation of glycolytic intermediates and increasing flux through the pentose phosphate pathway, which is a metabolic pathway parallel to glycolysis. Both rod and cone photoreceptors express the tumor form of pyruvate kinase M2. Recent studies from our laboratory show that PKM2 is functionally important for rod photoreceptor structure, function, and viability. However, the functional role of PKM2 in cones is not known. In this study, we conditionally deleted PKM2 in cones (cone-cre PKM2-KO) and found that loss of PKM2 results in the upregulation of PKM1 and a significant loss of cone function and cone degeneration in an age-dependent manner. Gene expression studies on cone-cre PKM2-KO show decreased expression of genes regulating glycolysis, PPP shunt, and fatty acid biosynthesis. Consistent with these observations, cones lacking PKM2 have significantly shorter cone outer segments than cones with PKM2. Our studies clearly suggest that PKM2 is essential for the anabolic process in cones to keep them alive for normal functioning and to support cone structure.
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Affiliation(s)
- Ammaji Rajala
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.,Dean McGee Eye Institute, Oklahoma City, OK, USA
| | - Yuhong Wang
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.,Dean McGee Eye Institute, Oklahoma City, OK, USA
| | - Krutik Soni
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.,Dean McGee Eye Institute, Oklahoma City, OK, USA
| | - Raju V S Rajala
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA. .,Dean McGee Eye Institute, Oklahoma City, OK, USA. .,Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA. .,Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.
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62
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Zhu S, Yam M, Wang Y, Linton JD, Grenell A, Hurley JB, Du J. Impact of euthanasia, dissection and postmortem delay on metabolic profile in mouse retina and RPE/choroid. Exp Eye Res 2018; 174:113-120. [PMID: 29864440 DOI: 10.1016/j.exer.2018.05.032] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2018] [Revised: 05/30/2018] [Accepted: 05/31/2018] [Indexed: 01/02/2023]
Abstract
Metabolomics studies in the retina and retinal pigment epithelium (RPE) in animal models or postmortem donors are essential to understanding the retinal metabolism and to revealing the underlying mechanisms of retinal degenerative diseases. We have studied how different methods of euthanasia (CO2 or cervical dislocation) different isolation procedures and postmortem delay affect metabolites in mouse retina and RPE/choroid using LC MS/MS and GC MS. Compared with cervical dislocation, CO2 exposure for 5 min dramatically degrades ATP and GTP into purine metabolites in the retina while raising intermediates in glucose metabolism and amino acids in the RPE/choroid. Isolation in cold buffer containing glucose has the least change in metabolites. Postmortem delay time-dependently and differentially impacts metabolites in the retina and RPE/choroid. In the postmortem retina, 18% of metabolites were changed at 0.5 h (h), 41% at 4 h and 51% at 8 h. However, only 6% of metabolites were changed in the postmortem RPE/choroid and it steadily increased to 20% at 8 h. Notably, both postmortem retina and RPE/choroid tissue showed increased purine metabolites. Storage of eyes in cold nutrient-rich medium substantially blocked the postmortem change in the retina and RPE/choroid. In conclusion, our study provides optimized methods to prepare fresh or postmortem retina and RPE/choroid tissue for metabolomics studies.
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Affiliation(s)
- Siyan Zhu
- Department of Ophthalmology, West Virginia University, Morgantown, WV 26506, USA; Department of Biochemistry, West Virginia University, Morgantown, WV 26506, USA
| | - Michelle Yam
- Department of Ophthalmology, West Virginia University, Morgantown, WV 26506, USA; Department of Biochemistry, West Virginia University, Morgantown, WV 26506, USA
| | - Yekai Wang
- Department of Ophthalmology, West Virginia University, Morgantown, WV 26506, USA; Department of Biochemistry, West Virginia University, Morgantown, WV 26506, USA
| | - Jonathan D Linton
- Department of Biochemistry, University of Washington, Seattle, WA 98109, USA
| | - Allison Grenell
- Department of Ophthalmology, West Virginia University, Morgantown, WV 26506, USA; Department of Biochemistry, West Virginia University, Morgantown, WV 26506, USA
| | - James B Hurley
- Department of Biochemistry, University of Washington, Seattle, WA 98109, USA; Department of Ophthalmology, University of Washington, Seattle, WA 98109, USA
| | - Jianhai Du
- Department of Ophthalmology, West Virginia University, Morgantown, WV 26506, USA; Department of Biochemistry, West Virginia University, Morgantown, WV 26506, USA.
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63
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DiCarlo JE, Mahajan VB, Tsang SH. Gene therapy and genome surgery in the retina. J Clin Invest 2018; 128:2177-2188. [PMID: 29856367 DOI: 10.1172/jci120429] [Citation(s) in RCA: 95] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Precision medicine seeks to treat disease with molecular specificity. Advances in genome sequence analysis, gene delivery, and genome surgery have allowed clinician-scientists to treat genetic conditions at the level of their pathology. As a result, progress in treating retinal disease using genetic tools has advanced tremendously over the past several decades. Breakthroughs in gene delivery vectors, both viral and nonviral, have allowed the delivery of genetic payloads in preclinical models of retinal disorders and have paved the way for numerous successful clinical trials. Moreover, the adaptation of CRISPR-Cas systems for genome engineering have enabled the correction of both recessive and dominant pathogenic alleles, expanding the disease-modifying power of gene therapies. Here, we highlight the translational progress of gene therapy and genome editing of several retinal disorders, including RPE65-, CEP290-, and GUY2D-associated Leber congenital amaurosis, as well as choroideremia, achromatopsia, Mer tyrosine kinase- (MERTK-) and RPGR X-linked retinitis pigmentosa, Usher syndrome, neovascular age-related macular degeneration, X-linked retinoschisis, Stargardt disease, and Leber hereditary optic neuropathy.
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Affiliation(s)
- James E DiCarlo
- 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, 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
| | - Vinit B Mahajan
- Omics Laboratory, Byers Eye Institute, Department of Ophthalmology, Stanford University, Palo Alto, California, USA.,Veterans Affairs Palo Alto Health Care System, Palo Alto, California, USA
| | - Stephen H Tsang
- 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, 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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64
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Park KS, Xu CL, Cui X, Tsang SH. Reprogramming the metabolome rescues retinal degeneration. Cell Mol Life Sci 2018; 75:1559-1566. [PMID: 29332245 PMCID: PMC9377522 DOI: 10.1007/s00018-018-2744-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Revised: 12/27/2017] [Accepted: 01/02/2018] [Indexed: 02/03/2023]
Abstract
Metabolomics studies in the context of ophthalmology have largely focused on identifying metabolite concentrations that characterize specific retinal diseases. Studies involving mass spectrometry (MS) and nuclear magnetic resonance (NMR) spectroscopy have shown that individuals suffering from retinal diseases exhibit metabolic profiles that markedly differ from those of control individuals, supporting the notion that metabolites may serve as easily identifiable biomarkers for specific conditions. An emerging branch of metabolomics resulting from biomarker studies, however, involves the study of retinal metabolic dysfunction as causes of degeneration. Recent publications have identified a number of metabolic processes-including but not limited to glucose and oxygen metabolism-that, when perturbed, play a role in the degeneration of photoreceptor cells. As a result, such studies have led to further research elucidating methods for prolonging photoreceptor survival in an effort to halt degeneration in its early stages. This review will explore the ways in which metabolomics has deepened our understanding of the causes of retinal degeneration and discuss how metabolomics can be used to prevent retinal degeneration from progressing to its later disease stages.
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Affiliation(s)
- Karen Sophia Park
- Jonas Children's Vision Care and Bernard & Shirlee Brown Glaucoma Laboratory, Department of Ophthalmology, Columbia University, New York, NY, USA
- Edward S. Harkness Eye Institute, New York-Presbyterian Hospital, New York, NY, USA
| | - Christine L Xu
- Jonas Children's Vision Care and Bernard & Shirlee Brown Glaucoma Laboratory, Department of Ophthalmology, Columbia University, New York, NY, USA
- 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, Department of Ophthalmology, Columbia University, New York, NY, USA
- Edward S. Harkness Eye Institute, New York-Presbyterian Hospital, New York, NY, USA
| | - Stephen H Tsang
- Jonas Children's Vision Care and Bernard & Shirlee Brown Glaucoma Laboratory, Department of Ophthalmology, Columbia University, New York, NY, USA.
- Edward S. Harkness Eye Institute, New York-Presbyterian Hospital, New York, NY, USA.
- Departments of Ophthalmology, Pathology, and Cell Biology, College of Physicians and Surgeons, Columbia University, New York, NY, USA.
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65
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Rajagopal R, Zhang S, Wei X, Doggett T, Adak S, Enright J, Shah V, Ling G, Chen S, Yoshino J, Hsu FF, Semenkovich CF. Retinal de novo lipogenesis coordinates neurotrophic signaling to maintain vision. JCI Insight 2018; 3:97076. [PMID: 29321376 PMCID: PMC5821215 DOI: 10.1172/jci.insight.97076] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Accepted: 11/28/2017] [Indexed: 11/17/2022] Open
Abstract
Membrane lipid composition is central to the highly specialized functions of neurological tissues. In the retina, abnormal lipid metabolism causes severe forms of blindness, often through poorly understood neuronal cell death. Here, we demonstrate that deleting the de novo lipogenic enzyme fatty acid synthase (FAS) from the neural retina, but not the vascular retina, results in progressive neurodegeneration and blindness with a temporal pattern resembling rodent models of retinitis pigmentosa. Blindness was not rescued by protection from light-evoked activity; by eating a diet enriched in palmitate, the product of the FAS reaction; or by treatment with the PPARα agonist fenofibrate. Vision loss was due to aberrant synaptic structure, blunted responsiveness to glial-derived neurotrophic factor and ciliary neurotrophic factor, and eventual apoptotic cell loss. This progressive neurodegeneration was associated with decreased membrane cholesterol content, as well as loss of discrete n-3 polyunsaturated fatty acid- and saturated fatty acid-containing phospholipid species within specialized membrane microdomains. Neurotrophic signaling was restored by exogenous cholesterol delivery. These findings implicate de novo lipogenesis in neurotrophin-dependent cell survival by maintaining retinal membrane configuration and lipid composition, and they suggest that ongoing lipogenesis may be required to prevent cell death in many forms of retinopathy.
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Affiliation(s)
| | - Sheng Zhang
- Department of Ophthalmology and Visual Sciences
| | - Xiaochao Wei
- Division of Endocrinology, Metabolism, and Lipid Research
| | | | - Sangeeta Adak
- Division of Endocrinology, Metabolism, and Lipid Research
| | | | - Vaishali Shah
- Division of Endocrinology, Metabolism, and Lipid Research
| | - Guoyu Ling
- Division of Endocrinology, Metabolism, and Lipid Research
| | | | - Jun Yoshino
- Division of Geriatrics and Nutritional Science, and
| | - Fong-Fu Hsu
- Division of Endocrinology, Metabolism, and Lipid Research
| | - Clay F Semenkovich
- Division of Endocrinology, Metabolism, and Lipid Research.,Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, Missouri, USA
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66
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Wu WH, Tsai YT, Justus S, Cho GY, Sengillo JD, Xu Y, Cabral T, Lin CS, Bassuk AG, Mahajan VB, Tsang SH. CRISPR Repair Reveals Causative Mutation in a Preclinical Model of Retinitis Pigmentosa: A Brief Methodology. Methods Mol Biol 2018; 1715:191-205. [PMID: 29188514 PMCID: PMC9119419 DOI: 10.1007/978-1-4939-7522-8_13] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/17/2023]
Abstract
CRISPR/Cas9 genome engineering is currently the leading genome surgery technology in most genetics laboratories. Combined with other complementary techniques, it serves as a powerful tool for uncovering genotype-phenotype correlations. Here, we describe a simplified protocol that was used in our publication, CRISPR Repair Reveals Causative Mutation in a Preclinical Model of Retinitis Pigmentosa, providing an overview of each section of the experimental process.
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Affiliation(s)
- Wen-Hsuan Wu
- Jonas Children's Vision Care, Columbia University Medical Center, New York, NY, USA
- Bernard & Shirlee Brown Glaucoma Laboratory, Columbia University Medical Center, New York, NY, USA
- Department of Ophthalmology, Columbia University, New York, NY, USA
| | - Yi-Ting Tsai
- Jonas Children's Vision Care, Columbia University Medical Center, New York, NY, USA
- Bernard & Shirlee Brown Glaucoma Laboratory, Columbia University Medical Center, New York, NY, USA
- Department of Ophthalmology, Columbia University, New York, NY, USA
| | - Sally Justus
- Jonas Children's Vision Care, Columbia University Medical Center, New York, NY, USA
- Bernard & Shirlee Brown Glaucoma Laboratory, Columbia University Medical Center, New York, NY, USA
- Department of Ophthalmology, Columbia University, New York, NY, USA
| | - Galaxy Y Cho
- Jonas Children's Vision Care, Columbia University Medical Center, New York, NY, USA
- Bernard & Shirlee Brown Glaucoma Laboratory, Columbia University Medical Center, New York, NY, USA
- Department of Ophthalmology, Columbia University, New York, NY, USA
| | - Jesse D Sengillo
- Jonas Children's Vision Care, Columbia University Medical Center, New York, NY, USA
- Bernard & Shirlee Brown Glaucoma Laboratory, Columbia University Medical Center, New York, NY, USA
- Department of Ophthalmology, Columbia University, New York, NY, USA
- State University of New York Downstate Medical Center, Brooklyn, NY, USA
| | - Yu Xu
- Jonas Children's Vision Care, Columbia University Medical Center, New York, NY, USA
- Bernard & Shirlee Brown Glaucoma Laboratory, Columbia University Medical Center, New York, NY, USA
- Department of Ophthalmology, Columbia University, New York, NY, USA
- Department of Ophthalmology, Xinhua Hospital affiliated to Shanghai Jiao Tong, University School of Medicine, Shanghai, China
| | - Thiago Cabral
- Jonas Children's Vision Care, Columbia University Medical Center, New York, NY, USA
- Bernard & Shirlee Brown Glaucoma Laboratory, Columbia University Medical Center, New York, NY, USA
- Department of Ophthalmology, Columbia University, New York, NY, USA
- Department of Ophthalmology, Federal University of Sao Paulo (UNIFESP), São Paulo, Brazil
- Department of Ophthalmology, Federal University of Espírito Santo (UFES), Vitória, Brazil
| | - Chyuan-Sheng Lin
- Department of Pathology & Cell Biology, Columbia University Medical Center, New York, NY, USA
| | - Alexander G Bassuk
- Department of Pediatrics and Neurology, University of Iowa, Iowa City, IA, USA
| | - Vinit B Mahajan
- Omics Laboratory, Stanford University , Palo Alto, CA, USA
- Department of Ophthalmology, Byers Eye Institute, Stanford University , Palo Alto, CA, USA
| | - Stephen H Tsang
- Jonas Children's Vision Care, Columbia University Medical Center, New York, NY, USA.
- Bernard & Shirlee Brown Glaucoma Laboratory, Columbia University Medical Center, New York, NY, USA.
- Department of Ophthalmology, Columbia University, New York, NY, USA.
- Department of Pathology & Cell Biology, Institute of Human Nutrition, College of Physicians and Surgeons, Columbia University, New York, NY, USA.
- Edward S. Harkness Eye Institute, Columbia University, New York, NY, USA.
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67
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Wubben TJ, Pawar M, Smith A, Toolan K, Hager H, Besirli CG. Photoreceptor metabolic reprogramming provides survival advantage in acute stress while causing chronic degeneration. Sci Rep 2017; 7:17863. [PMID: 29259242 PMCID: PMC5736549 DOI: 10.1038/s41598-017-18098-z] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Accepted: 12/05/2017] [Indexed: 11/16/2022] Open
Abstract
Photoreceptor death is the root cause of vision loss in many retinal disorders, and there is an unmet need for neuroprotective modalities to improve photoreceptor survival. The biosynthetic requirement of photoreceptors is among the highest in the body, and to meet this demand, photoreceptors maintain their ability to perform aerobic glycolysis. This highly regulated form of glycolysis allows cells to efficiently budget their metabolic needs and may be a critical link between photoreceptor function and survival. Pyruvate kinase muscle isozyme 2 (PKM2) is a key regulator of aerobic glycolysis. In the present study, we characterized the effect of PKM2 deletion on baseline functioning and survival of photoreceptors over time by utilizing a photoreceptor-specific, PKM2 knockout mouse model. We found that upon PKM2 deletion, PKM1 is upregulated in the outer retina and there is increased expression of genes involved in glucose metabolism, which led to chronic degenerative changes in the outer retina of these mice. We also discovered that this metabolic reprogramming provided a survival advantage to photoreceptors in an experimental model of retinal detachment. This study strongly supports the hypothesis that reprogramming metabolism may be a novel therapeutic strategy for photoreceptor neuroprotection during acute stress.
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Affiliation(s)
- Thomas J Wubben
- University of Michigan, Kellogg Eye Center, Department of Ophthalmology and Visual Sciences, Ann Arbor, Michigan, USA
| | - Mercy Pawar
- University of Michigan, Kellogg Eye Center, Department of Ophthalmology and Visual Sciences, Ann Arbor, Michigan, USA
| | - Andrew Smith
- University of Michigan, Kellogg Eye Center, Department of Ophthalmology and Visual Sciences, Ann Arbor, Michigan, USA
| | - Kevin Toolan
- University of Michigan, Kellogg Eye Center, Department of Ophthalmology and Visual Sciences, Ann Arbor, Michigan, USA
| | - Heather Hager
- University of Michigan, Kellogg Eye Center, Department of Ophthalmology and Visual Sciences, Ann Arbor, Michigan, USA
| | - Cagri G Besirli
- University of Michigan, Kellogg Eye Center, Department of Ophthalmology and Visual Sciences, Ann Arbor, Michigan, USA.
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68
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Kanow MA, Giarmarco MM, Jankowski CS, Tsantilas K, Engel AL, Du J, Linton JD, Farnsworth CC, Sloat SR, Rountree A, Sweet IR, Lindsay KJ, Parker ED, Brockerhoff SE, Sadilek M, Chao JR, Hurley JB. Biochemical adaptations of the retina and retinal pigment epithelium support a metabolic ecosystem in the vertebrate eye. eLife 2017; 6:28899. [PMID: 28901286 PMCID: PMC5617631 DOI: 10.7554/elife.28899] [Citation(s) in RCA: 236] [Impact Index Per Article: 33.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Accepted: 09/12/2017] [Indexed: 12/12/2022] Open
Abstract
Here we report multiple lines of evidence for a comprehensive model of energy metabolism in the vertebrate eye. Metabolic flux, locations of key enzymes, and our finding that glucose enters mouse and zebrafish retinas mostly through photoreceptors support a conceptually new model for retinal metabolism. In this model, glucose from the choroidal blood passes through the retinal pigment epithelium to the retina where photoreceptors convert it to lactate. Photoreceptors then export the lactate as fuel for the retinal pigment epithelium and for neighboring Müller glial cells. We used human retinal epithelial cells to show that lactate can suppress consumption of glucose by the retinal pigment epithelium. Suppression of glucose consumption in the retinal pigment epithelium can increase the amount of glucose that reaches the retina. This framework for understanding metabolic relationships in the vertebrate retina provides new insights into the underlying causes of retinal disease and age-related vision loss.
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Affiliation(s)
- Mark A Kanow
- Department of Biochemistry, University of Washington, Seattle, United States
| | | | - Connor Sr Jankowski
- Department of Biochemistry, University of Washington, Seattle, United States
| | - Kristine Tsantilas
- Department of Biochemistry, University of Washington, Seattle, United States
| | - Abbi L Engel
- Department of Ophthalmology, University of Washington, Seattle, United States
| | - Jianhai Du
- Department of Ophthalmology, West Virginia University, Morgantown, United States.,Department of Biochemistry, West Virginia University, Morgantown, United States
| | - Jonathan D Linton
- Department of Biochemistry, University of Washington, Seattle, United States.,Department of Ophthalmology, University of Washington, Seattle, United States
| | | | - Stephanie R Sloat
- Department of Biochemistry, University of Washington, Seattle, United States
| | - Austin Rountree
- Department of Medicine, UW Diabetes Institute, University of Washington, Seattle, United States
| | - Ian R Sweet
- Department of Medicine, UW Diabetes Institute, University of Washington, Seattle, United States
| | - Ken J Lindsay
- Department of Biochemistry, University of Washington, Seattle, United States.,Fred Hutchinson Cancer Research Center, Seattle, United States
| | - Edward D Parker
- Department of Ophthalmology, University of Washington, Seattle, United States
| | - Susan E Brockerhoff
- Department of Biochemistry, University of Washington, Seattle, United States.,Department of Ophthalmology, University of Washington, Seattle, United States
| | - Martin Sadilek
- Department of Chemistry, University of Washington, Seattle, United States
| | - Jennifer R Chao
- Department of Ophthalmology, University of Washington, Seattle, United States
| | - James B Hurley
- Department of Biochemistry, University of Washington, Seattle, United States.,Department of Ophthalmology, University of Washington, Seattle, United States
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69
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Kaplan HJ, Wang W, Dean DC. Restoration of Cone Photoreceptor Function in Retinitis Pigmentosa. Transl Vis Sci Technol 2017; 6:5. [PMID: 28900578 PMCID: PMC5588910 DOI: 10.1167/tvst.6.5.5] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2017] [Accepted: 07/17/2017] [Indexed: 01/12/2023] Open
Affiliation(s)
- Henry J Kaplan
- University of Louisville, Department of Ophthalmology and Visual Sciences, Louisville, KY, USA
| | - Wei Wang
- University of Louisville, Department of Ophthalmology and Visual Sciences, Louisville, KY, USA
| | - Douglas C Dean
- University of Louisville, Department of Ophthalmology and Visual Sciences, Louisville, KY, USA.,University of Louisville, Molecular Targets Program, James Graham Brown Cancer Center, Louisville, KY, USA
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70
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Chinchore Y, Begaj T, Wu D, Drokhlyansky E, Cepko CL. Glycolytic reliance promotes anabolism in photoreceptors. eLife 2017; 6. [PMID: 28598329 PMCID: PMC5499945 DOI: 10.7554/elife.25946] [Citation(s) in RCA: 116] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Accepted: 06/01/2017] [Indexed: 12/18/2022] Open
Abstract
Vertebrate photoreceptors are among the most metabolically active cells, exhibiting a high rate of ATP consumption. This is coupled with a high anabolic demand, necessitated by the diurnal turnover of a specialized membrane-rich organelle, the outer segment, which is the primary site of phototransduction. How photoreceptors balance their catabolic and anabolic demands is poorly understood. Here, we show that rod photoreceptors in mice rely on glycolysis for their outer segment biogenesis. Genetic perturbations targeting allostery or key regulatory nodes in the glycolytic pathway impacted the size of the outer segments. Fibroblast growth factor signaling was found to regulate glycolysis, with antagonism of this pathway resulting in anabolic deficits. These data demonstrate the cell autonomous role of the glycolytic pathway in outer segment maintenance and provide evidence that aerobic glycolysis is part of a metabolic program that supports the biosynthetic needs of a normal neuronal cell type. DOI:http://dx.doi.org/10.7554/eLife.25946.001 Living cells need building materials and energy to grow and carry out their activities. Most cells in the body use sugars like glucose for these purposes. In a process known as glycolysis, cells break down glucose into molecules that are eventually converted to carbon dioxide and water to form the chemical ATP – the cellular currency for energy. Developing cells that have not yet fully specialized, and rapidly dividing cells, like cancer cells, consume large amounts of glucose via aerobic glycolysis (also known as the Warburg effect) as they require high levels of energy and building materials. As cells become more specialized and divide less often, they have a reduced need for building blocks, and adjust their consumption and breakdown of glucose accordingly. One exception is the photoreceptor cells, found in the light-sensitive part of our eyes. Although these specialized cells do not divide, they still need a lot of energy and building blocks to constantly renew their light-sensing and processing structures, and to capture and convert the information from the environment into signals. Previous research has shown that the eye also uses the Warburg effect. However, until now, it was not known whether the photoreceptors or other cells in the eye carry out this form of glycolysis. Using genetic tools, Chinchore et al. analysed how the photoreceptor cells in mice used glucose. The experiments demonstrated that the photoreceptors do indeed carry out the Warburg effect. Chinchore et al. further discovered that the Warburg effect is regulated by the same key enzymes and signalling molecules that cancer cells use. This indicates that specialized cells like photoreceptors might choose to retain certain metabolic features of their precursor cells, if they need to. These findings provide new insight into how photoreceptors use glucose. The next step will be to understand how aerobic glycolysis is regulated in healthy eyes as well as in eyes that are affected by degenerating diseases, which may ultimately lead to new ways of treating blindness. DOI:http://dx.doi.org/10.7554/eLife.25946.002
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Affiliation(s)
- Yashodhan Chinchore
- Departments of Genetics and Ophthalmology, Harvard Medical School, Boston, United States
| | - Tedi Begaj
- Departments of Genetics and Ophthalmology, Harvard Medical School, Boston, United States
| | - David Wu
- Departments of Genetics and Ophthalmology, Harvard Medical School, Boston, United States
| | - Eugene Drokhlyansky
- Departments of Genetics and Ophthalmology, Harvard Medical School, Boston, United States
| | - Constance L Cepko
- Departments of Genetics and Ophthalmology, Harvard Medical School, Boston, United States.,Howard Hughes Medical Institute, Harvard Medical School, Boston, United States
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71
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Genetic rescue models refute nonautonomous rod cell death in retinitis pigmentosa. Proc Natl Acad Sci U S A 2017; 114:5259-5264. [PMID: 28468800 DOI: 10.1073/pnas.1615394114] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Retinitis pigmentosa (RP) is an inherited neurodegenerative disease, in which the death of mutant rod photoreceptors leads secondarily to the non-cell autonomous death of cone photoreceptors. Gene therapy is a promising treatment strategy. Unfortunately, current methods of gene delivery treat only a fraction of diseased cells, yielding retinas that are a mosaic of treated and untreated rods, as well as cones. In this study, we created two RP mouse models to test whether dying, untreated rods negatively impact treated, rescued rods. In one model, treated and untreated rods were segregated. In the second model, treated and untreated rods were diffusely intermixed, and their ratio was controlled to achieve low-, medium-, or high-efficiency rescue. Analysis of these mosaic retinas demonstrated that rescued rods (and cones) survive, even when they are greatly outnumbered by dying photoreceptors. On the other hand, the rescued photoreceptors did exhibit long-term defects in their outer segments (OSs), which were less severe when more photoreceptors were treated. In summary, our study suggests that even low-efficiency gene therapy may achieve stable survival of rescued photoreceptors in RP patients, albeit with OS dysgenesis.
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72
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Cho GY, Justus S, Sengillo JD, Tsang SH. CRISPR in the Retina: Evaluation of Future Potential. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 1016:147-155. [DOI: 10.1007/978-3-319-63904-8_8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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