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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Kamat V, Grumbine MK, Bao K, Mokate K, Khalil G, Cook D, Clearwater B, Hirst R, Harman J, Boeck M, Fu Z, Smith LEH, Goswami M, Wubben TJ, Walker EM, Zhu J, Soleimanpour SA, Scarlett JM, Robbings BM, Hass D, Hurley JB, Sweet IR. A versatile pumpless multi-channel fluidics system for maintenance and real-time functional assessment of tissue and cells. Cell Rep Methods 2023; 3:100642. [PMID: 37963464 PMCID: PMC10694526 DOI: 10.1016/j.crmeth.2023.100642] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Revised: 07/24/2023] [Accepted: 10/20/2023] [Indexed: 11/16/2023]
Abstract
To address the needs of the life sciences community and the pharmaceutical industry in pre-clinical drug development to both maintain and continuously assess tissue metabolism and function with simple and rapid systems, we improved on the initial BaroFuse to develop it into a fully functional, pumpless, scalable multi-channel fluidics instrument that continuously measures changes in oxygen consumption and other endpoints in response to test compounds. We and several other laboratories assessed it with a wide range of tissue types including retina, pancreatic islets, liver, and hypothalamus with both aqueous and gaseous test compounds. The setup time was less than an hour for all collaborating groups, and there was close agreement between data obtained from the different laboratories. This easy-to-use system reliably generates real-time metabolic and functional data from tissue and cells in response to test compounds that will address a critical need in basic and applied research.
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Affiliation(s)
- Varun Kamat
- University of Washington Medicine Diabetes Institute, University of Washington, Seattle, WA 98109, USA
| | | | - Khang Bao
- EnTox Sciences, Inc., Mercer Island, WA 98040, USA
| | - Kedar Mokate
- University of Washington Medicine Diabetes Institute, University of Washington, Seattle, WA 98109, USA
| | - Gamal Khalil
- EnTox Sciences, Inc., Mercer Island, WA 98040, USA
| | - Daniel Cook
- EnTox Sciences, Inc., Mercer Island, WA 98040, USA
| | | | - Richard Hirst
- Technical Assembly Service Corporation, Seattle, WA 98109, USA
| | - Jarrod Harman
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Myriam Boeck
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA; Eye Center, Medical Center, Faculty of Medicine, University of Freiburg, Freiburg im Breisgau, Germany
| | - Zhongjie Fu
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Lois E H Smith
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Moloy Goswami
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI 48105, USA
| | - Thomas J Wubben
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI 48105, USA
| | - Emily M Walker
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI 98195, USA
| | - Jie Zhu
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI 98195, USA
| | - Scott A Soleimanpour
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI 98195, USA
| | - Jarrad M Scarlett
- University of Washington Medicine Diabetes Institute, University of Washington, Seattle, WA 98109, USA; Department of Pediatric Gastroenterology and Hepatology, Seattle Children's Hospital, Seattle, WA 98145, USA
| | - Brian M Robbings
- University of Washington Medicine Diabetes Institute, University of Washington, Seattle, WA 98109, USA; Department of Biochemistry, University of Washington, Seattle, WA 98109, USA
| | - Daniel Hass
- Department of Biochemistry, University of Washington, Seattle, WA 98109, USA
| | - James B Hurley
- Department of Biochemistry, University of Washington, Seattle, WA 98109, USA
| | - Ian R Sweet
- University of Washington Medicine Diabetes Institute, University of Washington, Seattle, WA 98109, USA; EnTox Sciences, Inc., Mercer Island, WA 98040, USA.
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Hass DT, Pandey K, Engel A, Horton N, Robbings BM, Lim R, Sadilek M, Zhang Q, Autterson GA, Miller JML, Chao JR, Hurley JB. Acetyl-CoA carboxylase Inhibition increases RPE cell fatty acid oxidation and limits apolipoprotein efflux. bioRxiv 2023:2023.11.07.566117. [PMID: 37986876 PMCID: PMC10659357 DOI: 10.1101/2023.11.07.566117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2023]
Abstract
Purpose In age-related macular degeneration (AMD) and Sorsby's fundus dystrophy (SFD), lipid-rich deposits known as drusen accumulate under the retinal pigment epithelium (RPE). Drusen may contribute to photoreceptor and RPE degeneration in AMD and SFD. We hypothesize that stimulating β-oxidation in RPE will reduce drusen accumulation. Inhibitors of acetyl-CoA carboxylase (ACC) stimulate β-oxidation and diminish lipid accumulation in fatty liver disease. In this report we test the hypothesis that an ACC inhibitor, Firsocostat, limits the accumulation of lipid deposits in cultured RPE cells. Methods We probed metabolism and cellular function in mouse RPE-choroid, human fetal- derived RPE cells, and induced pluripotent stem cell-derived RPE cells. We used 13 C6-glucose and 13 C16-palmitate to determine the effects of Firsocostat on glycolytic, Krebs cycle, and fatty acid metabolism. 13 C labeling of metabolites in these pathways were analyzed using gas chromatography-linked mass spectrometry. We quantified ApoE and VEGF release using enzyme-linked immunosorbent assays. Immunostaining of sectioned RPE was used to visualize ApoE deposits. RPE function was assessed by measuring the trans-epithelial electrical resistance (TEER). Results ACC inhibition with Firsocostat increases fatty acid oxidation and remodels lipid composition, glycolytic metabolism, lipoprotein release, and enhances TEER. When human serum is used to induce sub-RPE lipoprotein accumulation, fewer lipoproteins accumulate with Firsocostat. In a culture model of Sorsby's fundus dystrophy, Firsocostat also stimulates fatty acid oxidation, improves morphology, and increases TEER. Conclusions Firsocostat remodels intracellular metabolism and improves RPE resilience to serum-induced lipid deposition. This effect of ACC inhibition suggests that it could be an effective strategy for diminishing drusen accumulation in the eyes of patients with AMD.
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Grumbine MK, Kamat V, Bao K, Crupi T, Mokate K, Lim R, Chao JR, Robbings BM, Hass DT, Hurley JB, Sweet IR. Maintaining and Assessing Various Tissue and Cell Types of the Eye Using a Novel Pumpless Fluidics System. J Vis Exp 2023:10.3791/65399. [PMID: 37522735 PMCID: PMC10791547 DOI: 10.3791/65399] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/01/2023] Open
Abstract
Many in vitro models used to investigate tissue function and cell biology require a flow of media to provide adequate oxygenation and optimal cell conditions required for the maintenance of function and viability. Toward this end, we have developed a multi-channel flow culture system to maintain tissue and cells in culture and continuously assess function and viability by either in-line sensors and/or collection of outflow fractions. The system combines 8-channel, continuous optical sensing of oxygen consumption rate with a built-in fraction collector to simultaneously measure production rates of metabolites and hormone secretion. Although it is able to maintain and assess a wide range of tissue and cell models, including islets, muscle, and hypothalamus, here we describe its operating principles and the experimental preparations/protocols that we have used to investigate bioenergetic regulation of isolated mouse retina, mouse retinal pigment epithelium (RPE)-choroid-sclera, and cultured human RPE cells. Innovations in the design of the system, such as pumpless fluid flow, have produced a greatly simplified operation of a multi-channel flow system. Videos and images are shown that illustrate how to assemble, prepare the instrument for an experiment, and load the different tissue/cell models into the perifusion chambers. In addition, guidelines for selecting conditions for protocol- and tissue-specific experiments are delineated and discussed, including setting the correct flow rate to tissue ratio to obtain consistent and stable culture conditions and accurate determinations of consumption and production rates. The combination of optimal tissue maintenance and real-time assessment of multiple parameters yields highly informative data sets that will have great utility for research in the physiology of the eye and drug discovery for the treatment of impaired vision.
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Affiliation(s)
| | - Varun Kamat
- UW Medicine Diabetes Institute, University of Washington
| | | | | | - Kedar Mokate
- UW Medicine Diabetes Institute, University of Washington
| | - Rayne Lim
- Department of Ophthalmology, University of Washington
| | | | | | - Daniel T Hass
- Department of Biochemistry, University of Washington
| | | | - Ian R Sweet
- EnTox Sciences, Inc; UW Medicine Diabetes Institute, University of Washington;
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Berkowitz BA, Podolsky RH, Childers KL, Roberts R, Katz R, Waseem R, Robbings BM, Hass DT, Hurley JB, Sweet IR, Goodman C, Qian H, Alvisio B, Heaps S. Transducin-Deficient Rod Photoreceptors Evaluated With Optical Coherence Tomography and Oxygen Consumption Rate Energy Biomarkers. Invest Ophthalmol Vis Sci 2022; 63:22. [PMID: 36576748 PMCID: PMC9804021 DOI: 10.1167/iovs.63.13.22] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Purpose To test the hypothesis that rod energy biomarkers in light and dark are similar in mice without functional rod transducin (Gnat1rd17). Methods Gnat1rd17 and wildtype (WT) mice were studied in canonically low energy demand (light) and high energy demand (dark) conditions. We measured rod inner segment ellipsoid zone (ISez) profile shape, external limiting membrane-retinal pigment epithelium (ELM-RPE) thickness, and magnitude of a hyporeflective band (HB) intensity dip located between photoreceptor tips and apical RPE; antioxidants were given in a subset of mice. Oxygen consumption rate (OCR) and visual performance indexes were also measured. Results The lower energy demand expected in light-adapted wildtype retinas was associated with an elongated ISez, thicker ELM-RPE, and higher HB magnitude, and lower OCR compared to high energy demand conditions in the dark. Gnat1rd17 mice showed a wildtype-like ISez profile shape at 20 minutes of light that became rounder at 60 minutes; at both times, ELM-RPE was smaller than wildtype values, and the HB magnitude was unmeasurable. OCR was higher than in the dark. Light-adapted Gnat1rd17 mice biomarkers were unaffected by anti-oxidants. Gnat1rd17 mice showed modest outer nuclear layer thinning and no reduction in visual performance indexes. Conclusions Light-stimulated changes in all biomarkers in WT mice are consistent with the established light-induced decrease in net energy demand. In contrast, biomarker changes in Gnat1rd17 mice raise the possibility that light increases net energy demand in the absence of rod phototransduction.
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Affiliation(s)
- Bruce A Berkowitz
- Department of Ophthalmology, Visual and Anatomical Sciences, Wayne State University School of Medicine, Detroit, Michigan, United States
| | - Robert H Podolsky
- Biostatistics and Study Methodology, Children's National Hospital, Silver Spring, Maryland, United States
| | - Karen Lins Childers
- Beaumont Research Institute, Beaumont Health, Royal Oak, Michigan, United States
| | - Robin Roberts
- Department of Ophthalmology, Visual and Anatomical Sciences, Wayne State University School of Medicine, Detroit, Michigan, United States
| | - Ryan Katz
- Department of Ophthalmology, Visual and Anatomical Sciences, Wayne State University School of Medicine, Detroit, Michigan, United States
| | - Rida Waseem
- Department of Ophthalmology, Visual and Anatomical Sciences, Wayne State University School of Medicine, Detroit, Michigan, United States
| | - Brian M Robbings
- Department of Biochemistry, Department of Ophthalmology, University of Washington, Seattle, Washington, United States.,Department of Medicine, UW Medicine Diabetes Institute, University of Washington, Seattle, Washington, United States
| | - Daniel T Hass
- Department of Biochemistry, Department of Ophthalmology, University of Washington, Seattle, Washington, United States
| | - James B Hurley
- Department of Biochemistry, Department of Ophthalmology, University of Washington, Seattle, Washington, United States
| | - Ian R Sweet
- Department of Medicine, UW Medicine Diabetes Institute, University of Washington, Seattle, Washington, United States
| | - Cole Goodman
- Department of Ophthalmology, Visual and Anatomical Sciences, Wayne State University School of Medicine, Detroit, Michigan, United States
| | - Haohua Qian
- Visual Function Core, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Bruno Alvisio
- OSIO Bioinformatics Core, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Sam Heaps
- OSIO Bioinformatics Core, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
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Hass DT, Bisbach CM, Robbings BM, Sadilek M, Sweet IR, Hurley JB. Succinate metabolism in the retinal pigment epithelium uncouples respiration from ATP synthesis. Cell Rep 2022; 39:110917. [PMID: 35675773 PMCID: PMC9251713 DOI: 10.1016/j.celrep.2022.110917] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Revised: 04/08/2022] [Accepted: 05/12/2022] [Indexed: 11/28/2022] Open
Abstract
Fumarate can be a surrogate for O2 as a terminal electron acceptor in the electron transport chain. Reduction of fumarate produces succinate, which can be exported. It is debated whether intact tissues can import and oxidize succinate produced by other tissues. In a previous report, we showed that mitochondria in retinal pigment epithelium (RPE)-choroid preparations can use succinate to reduce O2 to H2O. However, cells in that preparation could have been disrupted during tissue isolation. We now use multiple strategies to quantify intactness of the isolated RPE-choroid tissue. We find that exogenous 13C4-succinate is oxidized by intact cells then exported as fumarate or malate. Unexpectedly, we also find that oxidation of succinate is different from oxidation of other substrates because it uncouples electron transport from ATP synthesis. Retinas produce and export succinate. Our findings imply that retina succinate may substantially increase O2 consumption by uncoupling adjacent RPE mitochondria. The retina releases succinate, a source of reducing power for mitochondria. Hass et al. outline a pathway by which retina succinate can enter intact RPE-choroid cells and stimulate mitochondrial respiration that is uncoupled from ATP synthesis. Rapid RPE succinate oxidation may limit O2 levels in the retina.
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Affiliation(s)
- Daniel T Hass
- Biochemistry Department, The University of Washington, Seattle, WA 98195, USA
| | - Celia M Bisbach
- Biochemistry Department, The University of Washington, Seattle, WA 98195, USA; Promega Corporation, 2800 Woods Hollow Road, Fitchburg, WI 53711, USA
| | - Brian M Robbings
- Biochemistry Department, The University of Washington, Seattle, WA 98195, USA; Diabetes Institute, The University of Washington, Seattle, WA 98109, USA
| | - Martin Sadilek
- Chemistry Department, The University of Washington, Seattle, WA 98195, USA
| | - Ian R Sweet
- Diabetes Institute, The University of Washington, Seattle, WA 98109, USA; Division of Metabolism, Endocrinology and Nutrition, The University of Washington, Seattle, WA 98195, USA
| | - James B Hurley
- Biochemistry Department, The University of Washington, Seattle, WA 98195, USA; Opthalmology Department, The University of Washington, Seattle, WA 98109, USA.
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Kamat V, Robbings BM, Jung SR, Kelly J, Hurley JB, Bube KP, Sweet IR. Correction: Fluidics system for resolving concentration-dependent effects of dissolved gases on tissue metabolism. eLife 2022; 11:77538. [PMID: 35156924 PMCID: PMC8843092 DOI: 10.7554/elife.77538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Accepted: 02/02/2022] [Indexed: 11/15/2022] Open
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8
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Kamat V, Robbings BM, Jung SR, Kelly J, Hurley JB, Bube KP, Sweet IR. Fluidics system for resolving concentration-dependent effects of dissolved gases on tissue metabolism. eLife 2021; 10:e66716. [PMID: 34734803 PMCID: PMC8660022 DOI: 10.7554/elife.66716] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Accepted: 11/01/2021] [Indexed: 12/15/2022] Open
Abstract
Oxygen (O2) and other dissolved gases such as the gasotransmitters H2S, CO, and NO affect cell metabolism and function. To evaluate effects of dissolved gases on processes in tissue, we developed a fluidics system that controls dissolved gases while simultaneously measuring parameters of electron transport, metabolism, and secretory function. We use pancreatic islets, retina, and liver from rodents to highlight its ability to assess effects of O2 and H2S. Protocols aimed at emulating hypoxia-reperfusion conditions resolved a previously unrecognized transient spike in O2 consumption rate (OCR) following replenishment of O2, and tissue-specific recovery of OCR following hypoxia. The system revealed both inhibitory and stimulatory effects of H2S on insulin secretion rate from isolated islets. The unique ability of this new system to quantify metabolic state and cell function in response to precise changes in dissolved gases provides a powerful platform for cell physiologists to study a wide range of disease states.
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Affiliation(s)
- Varun Kamat
- University of Washington Medicine Diabetes Institute, University of WashingtonSeattleUnited States
| | - Brian M Robbings
- University of Washington Medicine Diabetes Institute, University of WashingtonSeattleUnited States
- Department of Biochemistry, University of WashingtonSeattleUnited States
| | - Seung-Ryoung Jung
- University of Washington Medicine Diabetes Institute, University of WashingtonSeattleUnited States
| | | | - James B Hurley
- Department of Biochemistry, University of WashingtonSeattleUnited States
| | - Kenneth P Bube
- Department of Mathematics, University of WashingtonSeattleUnited States
| | - Ian R Sweet
- University of Washington Medicine Diabetes Institute, University of WashingtonSeattleUnited States
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Tsantilas KA, Cleghorn WM, Bisbach CM, Whitson JA, Hass DT, Robbings BM, Sadilek M, Linton JD, Rountree AM, Valencia AP, Sweetwyne MT, Campbell MD, Zhang H, Jankowski CSR, Sweet IR, Marcinek DJ, Rabinovitch PS, Hurley JB. An Analysis of Metabolic Changes in the Retina and Retinal Pigment Epithelium of Aging Mice. Invest Ophthalmol Vis Sci 2021; 62:20. [PMID: 34797906 PMCID: PMC8606884 DOI: 10.1167/iovs.62.14.20] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Purpose The purpose of this study was to present our hypothesis that aging alters metabolic function in ocular tissues. We tested the hypothesis by measuring metabolism in aged murine tissues alongside retinal responses to light. Methods Scotopic and photopic electroretinogram (ERG) responses in young (3–6 months) and aged (23–26 months) C57Bl/6J mice were recorded. Metabolic flux in retina and eyecup explants was quantified using U-13C-glucose or U-13C-glutamine with gas chromatography-mass spectrometry (GC-MS), O2 consumption rate (OCR) in a perifusion apparatus, and quantifying adenosine triphosphatase (ATP) with a bioluminescence assay. Results Scotopic and photopic ERG responses were reduced in aged mice. Glucose metabolism, glutamine metabolism, OCR, and ATP pools in retinal explants were mostly unaffected in aged mice. In eyecups, glutamine usage in the Krebs Cycle decreased while glucose metabolism, OCR, and ATP pools remained stable. Conclusions Our examination of metabolism showed negligible impact of age on retina and an impairment of glutamine anaplerosis in eyecups. The metabolic stability of these tissues ex vivo suggests age-related metabolic alterations may not be intrinsic. Future experiments should focus on determining whether external factors including nutrient supply, oxygen availability, or structural changes influence ocular metabolism in vivo.
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Affiliation(s)
- Kristine A Tsantilas
- Department of Biochemistry, University of Washington, Seattle, Washington, United States
| | - Whitney M Cleghorn
- Department of Biochemistry, University of Washington, Seattle, Washington, United States
| | - Celia M Bisbach
- Department of Biochemistry, University of Washington, Seattle, Washington, United States
| | - Jeremy A Whitson
- Department of Biology, Davidson College, Davidson, North Carolina, United States
| | - Daniel T Hass
- Department of Biochemistry, University of Washington, Seattle, Washington, United States
| | - Brian M Robbings
- Department of Biochemistry, University of Washington, Seattle, Washington, United States.,UW Diabetes Institute, University of Washington, Seattle, Washington, United States
| | - Martin Sadilek
- Department of Chemistry, University of Washington, Seattle, Washington, United States
| | - Jonathan D Linton
- Department of Biochemistry, University of Washington, Seattle, Washington, United States
| | - Austin M Rountree
- UW Diabetes Institute, University of Washington, Seattle, Washington, United States
| | - Ana P Valencia
- Department of Radiology, University of Washington, Seattle, Washington, United States
| | - Mariya T Sweetwyne
- Department of Laboratory Medicine & Pathology, University of Washington, Seattle, Washington, United States
| | - Matthew D Campbell
- Department of Radiology, University of Washington, Seattle, Washington, United States
| | - Huiliang Zhang
- Department of Pharmacology and Toxicology, College of Medicine, University of Arkansas for Medical Sciences, Little Rock, Arkansas, United States
| | - Connor S R Jankowski
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, United States.,Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey, United States
| | - Ian R Sweet
- UW Diabetes Institute, University of Washington, Seattle, Washington, United States
| | - David J Marcinek
- Department of Radiology, University of Washington, Seattle, Washington, United States
| | - Peter S Rabinovitch
- Department of Laboratory Medicine & Pathology, University of Washington, Seattle, Washington, United States
| | - James B Hurley
- Department of Biochemistry, University of Washington, Seattle, Washington, United States.,Department of Ophthalmology, University of Washington, Seattle, Washington, United States
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10
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Bisbach CM, Hass DT, Robbings BM, Rountree AM, Sadilek M, Sweet IR, Hurley JB. Succinate Can Shuttle Reducing Power from the Hypoxic Retina to the O 2-Rich Pigment Epithelium. Cell Rep 2021; 31:107606. [PMID: 32375026 DOI: 10.1016/j.celrep.2020.107606] [Citation(s) in RCA: 53] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Revised: 02/21/2020] [Accepted: 04/10/2020] [Indexed: 12/19/2022] Open
Abstract
When O2 is plentiful, the mitochondrial electron transport chain uses it as a terminal electron acceptor. However, the mammalian retina thrives in a hypoxic niche in the eye. We find that mitochondria in retinas adapt to their hypoxic environment by reversing the succinate dehydrogenase reaction to use fumarate to accept electrons instead of O2. Reverse succinate dehydrogenase activity produces succinate and is enhanced by hypoxia-induced downregulation of cytochrome oxidase. Retinas can export the succinate they produce to the neighboring O2-rich retinal pigment epithelium-choroid complex. There, succinate enhances O2 consumption by severalfold. Malate made from succinate in the pigment epithelium can then be imported into the retina, where it is converted to fumarate to again accept electrons in the reverse succinate dehydrogenase reaction. This malate-succinate shuttle can sustain these two tissues by transferring reducing power from an O2-poor tissue (retina) to an O2-rich one (retinal pigment epithelium-choroid).
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Affiliation(s)
- Celia M Bisbach
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
| | - Daniel T Hass
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
| | - Brian M Robbings
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA; UW Diabetes Institute, University of Washington, Seattle, WA 98195, USA
| | - Austin M Rountree
- UW Diabetes Institute, University of Washington, Seattle, WA 98195, USA
| | - Martin Sadilek
- Department of Chemistry, University of Washington, Seattle, WA 98195, USA
| | - Ian R Sweet
- UW Diabetes Institute, University of Washington, Seattle, WA 98195, USA
| | - James B Hurley
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA; Department of Ophthalmology, University of Washington, Seattle, WA 98195, USA.
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