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Feng J, Chen X, Li R, Xie Y, Zhang X, Guo X, Zhao L, Xu Z, Song Y, Song J, Bi H. Lactylome analysis reveals potential target modified proteins in the retina of form-deprivation myopia. iScience 2024; 27:110606. [PMID: 39246443 PMCID: PMC11379675 DOI: 10.1016/j.isci.2024.110606] [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: 11/15/2023] [Revised: 05/19/2024] [Accepted: 07/25/2024] [Indexed: 09/10/2024] Open
Abstract
The biological mechanisms underlying the development of myopia have not yet been completely elucidated. The retina is critical for visual signal processing, which primarily utilizes aerobic glycolysis to produce lactate as a metabolic end product. Lactate facilitates lysine lactylation (Kla), a posttranslational modification essential for transcriptional regulation. This study found increased glycolytic flux and lactate accumulation in the retinas of form-deprived myopic guinea pigs. Subsequently, a comprehensive analysis of Kla levels in retinal proteins revealed that Kla was upregulated at 124 sites in 92 proteins and downregulated at three sites in three proteins. Functional enrichment and protein interaction analyses showed significant enrichment in pathways related to energy metabolism, including glutathione metabolism, glycolysis, and the hypoxia-inducible factor-1 signaling pathway. Parallel-reaction monitoring confirmed data reliability. These findings suggest a connection between myopia and retinal energy metabolism imbalance, providing new insights into the pathogenesis of myopia.
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Affiliation(s)
- Jiaojiao Feng
- Shandong University of Traditional Chinese Medicine, Jinan 250014, China
| | - Xiaoniao Chen
- Department of Ophthalmology, Chinese PLA General Hospital, Beijing 100853, China
| | - Runkuan Li
- Shandong University of Traditional Chinese Medicine, Jinan 250014, China
| | - Yunxiao Xie
- Affiliated Eye Hospital of Shandong University of Traditional Chinese Medicine, Jinan 250002, China
- Shandong Academy of Eye Disease Prevention and Therapy, Shandong Provincial Key Laboratory of Integrated Traditional Chinese and Western Medicine for Prevention and Therapy of Ocular Diseases, Jinan 250002, China
| | - Xiuyan Zhang
- Affiliated Eye Hospital of Shandong University of Traditional Chinese Medicine, Jinan 250002, China
- Shandong Academy of Eye Disease Prevention and Therapy, Shandong Provincial Key Laboratory of Integrated Traditional Chinese and Western Medicine for Prevention and Therapy of Ocular Diseases, Jinan 250002, China
| | - Xiaoxiao Guo
- Shandong University of Traditional Chinese Medicine, Jinan 250014, China
| | - Lianghui Zhao
- Shandong University of Traditional Chinese Medicine, Jinan 250014, China
| | - Zhe Xu
- Shandong University of Traditional Chinese Medicine, Jinan 250014, China
| | - Yifan Song
- Shandong University of Traditional Chinese Medicine, Jinan 250014, China
| | - Jike Song
- Shandong University of Traditional Chinese Medicine, Jinan 250014, China
- Shandong Academy of Eye Disease Prevention and Therapy, Shandong Provincial Key Laboratory of Integrated Traditional Chinese and Western Medicine for Prevention and Therapy of Ocular Diseases, Jinan 250002, China
| | - Hongsheng Bi
- Affiliated Eye Hospital of Shandong University of Traditional Chinese Medicine, Jinan 250002, China
- Shandong Academy of Eye Disease Prevention and Therapy, Shandong Provincial Key Laboratory of Integrated Traditional Chinese and Western Medicine for Prevention and Therapy of Ocular Diseases, Jinan 250002, China
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Goswami MT, Weh E, Subramanya S, Weh KM, Durumutla HB, Hager H, Miller N, Chaudhury S, Andren A, Sajjakulnukit P, Besirli CG, Lyssiotis CA, Wubben TJ. Glutamine catabolism supports amino acid biosynthesis and suppresses the integrated stress response to promote photoreceptor survival. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.26.582525. [PMID: 38586045 PMCID: PMC10996599 DOI: 10.1101/2024.03.26.582525] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/09/2024]
Abstract
Photoreceptor loss results in vision loss in many blinding diseases, and metabolic dysfunction underlies photoreceptor degeneration. So, exploiting photoreceptor metabolism is an attractive strategy to prevent vision loss. Yet, the metabolic pathways that maintain photoreceptor health remain largely unknown. Here, we investigated the dependence of photoreceptors on Gln catabolism. Gln is converted to glutamate via glutaminase (GLS), so mice lacking GLS in rod photoreceptors were generated to inhibit Gln catabolism. Loss of GLS produced rapid rod photoreceptor degeneration. In vivo metabolomic methodologies and metabolic supplementation identified Gln catabolism as critical for glutamate and aspartate biosynthesis. Concordant with this amino acid deprivation, the integrated stress response (ISR) was activated with protein synthesis attenuation, and inhibiting the ISR delayed photoreceptor loss. Furthermore, supplementing asparagine, which is synthesized from aspartate, delayed photoreceptor degeneration. Hence, Gln catabolism is integral to photoreceptor health, and these data reveal a novel metabolic axis in these metabolically-demanding neurons.
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Affiliation(s)
- Moloy T. Goswami
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI 48105
| | - Eric Weh
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI 48105
| | - Shubha Subramanya
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI 48105
| | - Katherine M. Weh
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI 48105
| | - Hima Bindu Durumutla
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI 48105
- Molecular and Developmental Biology Graduate Program, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH 45229
| | - Heather Hager
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI 48105
| | - Nicholas Miller
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI 48105
| | - Sraboni Chaudhury
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI 48105
| | - Anthony Andren
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI 48109
| | - Peter Sajjakulnukit
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI 48109
| | - Cagri G. Besirli
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI 48105
| | - Costas A. Lyssiotis
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI 48109
- Department of Internal Medicine, Division of Gastroenterology and Hepatology, University of Michigan, Ann Arbor, MI 48109
- Rogel Cancer Center, University of Michigan, Ann Arbor, MI 48109
| | - Thomas J. Wubben
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI 48105
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Wu J, Jo DH, Fruttiger M, Kim JH. Cone cell dysfunction attenuates retinal neovascularization in oxygen-induced retinopathy mouse model. J Neurosci Res 2024; 102:e25316. [PMID: 38415926 DOI: 10.1002/jnr.25316] [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: 08/25/2023] [Revised: 01/21/2024] [Accepted: 02/19/2024] [Indexed: 02/29/2024]
Abstract
Aberrant neovascularization is the most common feature in retinopathy of prematurity (ROP), which leads to the retinal detachment and visual defects in neonates with a low gestational age eventually. Understanding the regulation of inappropriate angiogenic signaling benefits individuals at-risk. Recently, neural activity originating from the specific neural activity has been considered to contribute to retinal angiogenesis. Here, we explored the impact of cone cell dysfunction on oxygen-induced retinopathy (OIR), a mouse model commonly employed to understand retinal diseases associated with abnormal blood vessel growth, using the Gnat2cpfl3 (cone photoreceptor function loss-3) strain of mice (regardless of the sex), which is known for its inherent cone cell dysfunction. We found that the retinal avascular area, hypoxic area, and neovascular area were significantly attenuated in Gnat2cpfl3 OIR mice compared to those in C57BL/6 OIR mice. Moreover, the HIF-1α/VEGF axis was also reduced in Gnat2cpfl3 OIR mice. Collectively, our results indicated that cone cell dysfunction, as observed in Gnat2cpfl3 OIR mice, leads to attenuated retinal neovascularization. This finding suggests that retinal neural activity may precede and potentially influence the onset of pathological neovascularization.
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Affiliation(s)
- Jun Wu
- Fight Against Angiogenesis-Related Blindness (FARB) Laboratory, Biomedical Research Institute, Seoul National University Hospital, Seoul, Republic of Korea
- Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Dong Hyun Jo
- Department of Anatomy and Cell Biology, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Marcus Fruttiger
- UCL Institute of Ophthalmology, University College London, London, UK
| | - Jeong Hun Kim
- Fight Against Angiogenesis-Related Blindness (FARB) Laboratory, Biomedical Research Institute, Seoul National University Hospital, Seoul, Republic of Korea
- Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, Republic of Korea
- Department of Ophthalmology, Seoul National University College of Medicine, Seoul, Republic of Korea
- Global Excellence Center for Gene & Cell Therapy (GEC-GCT), Seoul National University Hospital, Seoul, Republic of Korea
- Institute of Reproductive Medicine and Population, Seoul National University College of Medicine, Seoul, Republic of Korea
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4
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Subramanya S, Goswami MT, Miller N, Weh E, Chaudhury S, Zhang L, Andren A, Hager H, Weh KM, Lyssiotis CA, Besirli CG, Wubben TJ. Rod photoreceptor-specific deletion of cytosolic aspartate aminotransferase, GOT1, causes retinal degeneration. FRONTIERS IN OPHTHALMOLOGY 2023; 3:1306019. [PMID: 38725581 PMCID: PMC11081273 DOI: 10.3389/fopht.2023.1306019] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 05/12/2024]
Abstract
Photoreceptor cell death is the cause of vision loss in many forms of retinal disease. Metabolic dysfunction within the outer retina has been shown to be an underlying factor contributing to photoreceptor loss. Therefore, a comprehensive understanding of the metabolic pathways essential to photoreceptor health and function is key to identifying novel neuroprotective strategies. Glutamic-oxaloacetic transaminase 1 (Got1) encodes for a cytosolic aspartate aminotransferase that reversibly catalyzes the transfer of an amino group between glutamate and aspartate and is an important aspect of the malate-aspartate shuttle (MAS), which transfers reducing equivalents from the cytosol to the mitochondrial matrix. Previous work has demonstrated that the activity of this enzyme is highest in photoreceptor inner segments. Furthermore, ex vivo studies have demonstrated that the retina relies on aspartate aminotransferase for amino acid metabolism. Importantly, aspartate aminotransferase has been suggested to be an early biomarker of retinal degeneration in retinitis pigmentosa and a possible target for neuroprotection. In the present study, we characterized the effect of Got1 deletion on photoreceptor metabolism, function, and survival in vivo by using a rod photoreceptor-specific, Got1 knockout mouse model. Loss of the GOT1 enzyme from rod photoreceptors resulted in age-related photoreceptor degeneration with an accumulation of retinal aspartate and NADH and alterations in the expression of genes involved in the MAS, the tricarboxylic acid (TCA) cycle, and redox balance. Hence, GOT1 is critical to in vivo photoreceptor metabolism, function, and survival.
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Affiliation(s)
- Shubha Subramanya
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI, United States
| | - Moloy T. Goswami
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI, United States
| | - Nicholas Miller
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI, United States
| | - Eric Weh
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI, United States
| | - Sraboni Chaudhury
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI, United States
| | - Li Zhang
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI, United States
| | - Anthony Andren
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI, United States
| | - Heather Hager
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI, United States
| | - Katherine M. Weh
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI, United States
| | - Costas A. Lyssiotis
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI, United States
- Department of Internal Medicine, Division of Gastroenterology and Hepatology, University of Michigan, Ann Arbor, MI, United States
- Rogel Cancer Center, University of Michigan, Ann Arbor, MI, United States
| | - Cagri G. Besirli
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI, United States
| | - Thomas J. Wubben
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI, United States
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Gowda GAN, Abell L, Tian R, Raftery D. Whole Body Distribution of Labile Coenzymes and Antioxidants in a Mouse Model as Visualized Using 1H NMR Spectroscopy. Anal Chem 2023; 95:6029-6037. [PMID: 36988554 PMCID: PMC10089975 DOI: 10.1021/acs.analchem.3c00054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/30/2023]
Abstract
Coenzyme A, acetyl coenzyme A, coenzymes of cellular energy, coenzymes of redox reactions, and antioxidants mediate biochemical reactions fundamental to the functioning of all living cells. There is an immense interest in measuring them routinely in biological specimens to gain insights into their roles in cellular functions and to help characterize the biological status. However, it is challenging to measure them ex vivo as they are sensitive to specimen harvesting, extraction, and measurement conditions. This challenge is largely underappreciated and carries the risk of grossly inaccurate measurements that lead to incorrect inferences. To date, several efforts have been focused on alleviating this challenge using NMR spectroscopy. However, a comprehensive solution for the measurement of the compounds in a wide variety of biological specimens is still lacking. As a part of addressing this challenge, we demonstrate here that the total pool of each group of unstable metabolites offers a starting place for the representation of labile metabolites in biological specimens. Based on this approach, in this proof-of-concept study, we determine the distribution of the labile compounds in different organs including heart, kidney, liver, brain, and skeletal muscle of a mouse model. The results were independently validated using different specimens and a different metabolite extraction protocol. Further, we show that both stable and unstable metabolites were distributed differentially in different organs, which signifies their differential functional roles, the knowledge of which is currently lacking for many metabolites. Intriguingly, the concentration of taurine, an amino sulfonic acid, in skeletal muscle is >30 mM, which is the highest for any metabolite in a mammalian tissue known to date. To the best of our knowledge, this is the first study to profile the whole body distribution of the labile and other high-concentration metabolites using NMR spectroscopy. The results may pave ways for gaining new insights into cellular functions in health and diseases.
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Affiliation(s)
- G. A. Nagana Gowda
- Northwest Metabolomics Research Center, University of Washington, Seattle, WA 98109
- Mitochondria and Metabolism Center, Anesthesiology and Pain Medicine, University of Washington, Seattle, WA 98109
| | - Lauren Abell
- Mitochondria and Metabolism Center, Anesthesiology and Pain Medicine, University of Washington, Seattle, WA 98109
| | - Rong Tian
- Mitochondria and Metabolism Center, Anesthesiology and Pain Medicine, University of Washington, Seattle, WA 98109
| | - Daniel Raftery
- Northwest Metabolomics Research Center, University of Washington, Seattle, WA 98109
- Mitochondria and Metabolism Center, Anesthesiology and Pain Medicine, University of Washington, Seattle, WA 98109
- Fred Hutchinson Cancer Research Center, Seattle, WA 98109
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6
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Zhu S, Huang J, Xu R, Wang Y, Wan Y, McNeel R, Parker E, Kolson D, Yam M, Webb B, Zhao C, Sigado J, Du J. Isocitrate dehydrogenase 3b is required for spermiogenesis but dispensable for retinal viability. J Biol Chem 2022; 298:102387. [PMID: 35985423 PMCID: PMC9478456 DOI: 10.1016/j.jbc.2022.102387] [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: 05/11/2022] [Revised: 08/08/2022] [Accepted: 08/10/2022] [Indexed: 12/02/2022] Open
Abstract
Isocitrate dehydrogenase 3 (IDH3) is a key enzyme in the mitochondrial tricarboxylic acid (TCA) cycle, which catalyzes the decarboxylation of isocitrate into α-ketoglutarate and concurrently converts NAD+ into NADH. Dysfunction of IDH3B, the β subunit of IDH3, has been previously correlated with retinal degeneration and male infertility in humans, but tissue-specific effects of IDH3 dysfunction are unclear. Here, we generated Idh3b-KO mice and found that IDH3B is essential for IDH3 activity in multiple tissues. We determined that loss of Idh3b in mice causes substantial accumulation of isocitrate and its precursors in the TCA cycle, particularly in the testes, whereas the levels of the downstream metabolites remain unchanged or slightly increased. However, the Idh3b-KO mice did not fully recapitulate the defects observed in humans. Global deletion of Idh3b only causes male infertility but not retinal degeneration in mice. Our investigation showed that loss of Idh3b causes an energetic deficit and disrupts the biogenesis of acrosome and flagellum, resulting in spermiogenesis arrestment in sperm cells. Together, we demonstrate that IDH3B controls its substrate levels in the TCA cycle, and it is required for sperm mitochondrial metabolism and spermiogenesis, highlighting the importance of the tissue-specific function of the ubiquitous TCA cycle.
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Affiliation(s)
- Siyan Zhu
- Department of Ophthalmology and Visual Sciences, West Virginia University, Morgantown, WV 26506; Department of Biochemistry, West Virginia University, Morgantown, WV 26506; Department of Pharmaceutical and Pharmacological Science, West Virginia University, Morgantown, WV 26506
| | - Jiancheng Huang
- Department of Ophthalmology and Visual Sciences, West Virginia University, Morgantown, WV 26506; Department of Biochemistry, West Virginia University, Morgantown, WV 26506; Eye Institute, Eye & ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China; NHC Key Laboratory of Myopia (Fudan University), Key Laboratory of Myopia, Chinese Academy of Medical Sciences, and Shanghai Key Laboratory of Visual Impairment and Restoration (Fudan University), Shanghai, China
| | - Rong Xu
- Department of Ophthalmology and Visual Sciences, West Virginia University, Morgantown, WV 26506; Department of Biochemistry, West Virginia University, Morgantown, WV 26506
| | - Yekai Wang
- Department of Ophthalmology and Visual Sciences, West Virginia University, Morgantown, WV 26506; Department of Biochemistry, West Virginia University, Morgantown, WV 26506
| | - Yiming Wan
- Department of Biomedical Engineering Department, Stony Brook University, Stony Brook, NY 11794
| | - Rachel McNeel
- Department of Ophthalmology and Visual Sciences, West Virginia University, Morgantown, WV 26506; Department of Biochemistry, West Virginia University, Morgantown, WV 26506
| | - Edward Parker
- Department of Ophthalmology, University of Washington, Seattle, WA 98109
| | - Douglas Kolson
- Department of Ophthalmology and Visual Sciences, West Virginia University, Morgantown, WV 26506
| | - Michelle Yam
- Department of Ophthalmology and Visual Sciences, West Virginia University, Morgantown, WV 26506; Department of Biochemistry, West Virginia University, Morgantown, WV 26506
| | - Bradley Webb
- Department of Biochemistry, West Virginia University, Morgantown, WV 26506
| | - Chen Zhao
- Eye Institute, Eye & ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China; NHC Key Laboratory of Myopia (Fudan University), Key Laboratory of Myopia, Chinese Academy of Medical Sciences, and Shanghai Key Laboratory of Visual Impairment and Restoration (Fudan University), Shanghai, China
| | - Jenna Sigado
- Department of Ophthalmology and Visual Sciences, West Virginia University, Morgantown, WV 26506; Department of Biochemistry, West Virginia University, Morgantown, WV 26506
| | - Jianhai Du
- Department of Ophthalmology and Visual Sciences, West Virginia University, Morgantown, WV 26506; Department of Biochemistry, West Virginia University, Morgantown, WV 26506.
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7
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Daniele LL, Han JY, Samuels IS, Komirisetty R, Mehta N, McCord JL, Yu M, Wang Y, Boesze-Battaglia K, Bell BA, Du J, Peachey NS, Philp NJ. Glucose uptake by GLUT1 in photoreceptors is essential for outer segment renewal and rod photoreceptor survival. FASEB J 2022; 36:e22428. [PMID: 35766190 PMCID: PMC9438481 DOI: 10.1096/fj.202200369r] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Revised: 05/27/2022] [Accepted: 06/10/2022] [Indexed: 02/07/2023]
Abstract
Photoreceptors consume glucose supplied by the choriocapillaris to support phototransduction and outer segment (OS) renewal. Reduced glucose supply underlies photoreceptor cell death in inherited retinal degeneration and age-related retinal disease. We have previously shown that restricting glucose transport into the outer retina by conditional deletion of Slc2a1 encoding GLUT1 resulted in photoreceptor loss and impaired OS renewal. However, retinal neurons, glia, and the retinal pigment epithelium play specialized, synergistic roles in metabolite supply and exchange, and the cell-specific map of glucose uptake and utilization in the retina is incomplete. In these studies, we conditionally deleted Slc2a1 in a pan-retinal or rod-specific manner to better understand how glucose is utilized in the retina. Using non-invasive ocular imaging, electroretinography, and histochemical and biochemical analyses we show that genetic deletion of Slc2a1 from retinal neurons and Müller glia results in reduced OS growth and progressive rod but not cone photoreceptor cell death. Rhodopsin levels were severely decreased even at postnatal day 20 when OS length was relatively normal. Arrestin levels were not changed suggesting that glucose uptake is required to synthesize membrane glycoproteins. Rod-specific deletion of Slc2a1 resulted in similar changes in OS length and rod photoreceptor cell death. These studies demonstrate that glucose is an essential carbon source for rod photoreceptor cell OS maintenance and viability.
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Affiliation(s)
- Lauren L. Daniele
- Department of Pathology, Anatomy, and Cell Biology, Thomas
Jefferson University, Philadelphia, PA
| | - John Y.S. Han
- Department of Pathology, Anatomy, and Cell Biology, Thomas
Jefferson University, Philadelphia, PA
| | - Ivy S. Samuels
- Cole Eye Institute, Cleveland Clinic, Cleveland, OH
- Louis Stokes Cleveland VA Medical Center, Cleveland,
OH
| | - Ravikiran Komirisetty
- Department of Pathology, Anatomy, and Cell Biology, Thomas
Jefferson University, Philadelphia, PA
| | - Nikhil Mehta
- Department of Pathology, Anatomy, and Cell Biology, Thomas
Jefferson University, Philadelphia, PA
| | - Jessica L. McCord
- Department of Pathology, Anatomy, and Cell Biology, Thomas
Jefferson University, Philadelphia, PA
| | - Minzhong Yu
- Cole Eye Institute, Cleveland Clinic, Cleveland, OH
- Department of Ophthalmology, Cleveland Clinic Lerner
College of Medicine of Case Western Reserve University, Cleveland, OH
| | - Yekai Wang
- Department of Ophthalmology and Visual Sciences, West
Virginia University, Morgantown, WV
- Department of Biochemistry, West Virginia University,
Morgantown, WV
| | - Kathleen Boesze-Battaglia
- Department of Basic and Translational Sciences, Penn Dental
Medicine, University of Pennsylvania, Philadelphia, PA
| | - Brent A. Bell
- Department of Ophthalmology, University of Pennsylvania,
Philadelphia, PA
| | - Jianhai Du
- Department of Ophthalmology and Visual Sciences, West
Virginia University, Morgantown, WV
- Department of Biochemistry, West Virginia University,
Morgantown, WV
| | - Neal S. Peachey
- Cole Eye Institute, Cleveland Clinic, Cleveland, OH
- Louis Stokes Cleveland VA Medical Center, Cleveland,
OH
- Department of Ophthalmology, Cleveland Clinic Lerner
College of Medicine of Case Western Reserve University, Cleveland, OH
| | - Nancy J. Philp
- Department of Pathology, Anatomy, and Cell Biology, Thomas
Jefferson University, Philadelphia, PA
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Aparicio A, Camacho ET, Philp NJ, Wirkus SA. A mathematical model of GLUT1 modulation in rods and RPE and its differential impact in cell metabolism. Sci Rep 2022; 12:10645. [PMID: 35739198 PMCID: PMC9226191 DOI: 10.1038/s41598-022-13950-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Accepted: 05/31/2022] [Indexed: 11/10/2022] Open
Abstract
We present a mathematical model of key glucose metabolic pathways in two cells of the human retina: the rods and the retinal pigmented epithelium (RPE). Computational simulations of glucose transporter 1 (GLUT1) inhibition in the model accurately reproduce experimental data from conditional knockout mice and reveal that modification of GLUT1 expression levels of both cells differentially impacts their metabolism. We hypothesize that, under glucose scarcity, the RPE's energy producing pathways are altered in order to preserve its functionality, impacting the photoreceptors' outer segment renewal. On the other hand, when glucose is limited in the rods, aerobic glycolysis is preserved, which maintains the lactate contribution to the RPE.
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Affiliation(s)
- Andrea Aparicio
- School of Mathematical and Natural Sciences, Arizona State University, Glendale, AZ, USA.
| | - Erika T Camacho
- School of Mathematical and Natural Sciences, Arizona State University, Glendale, AZ, USA
| | - Nancy J Philp
- Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA, USA
| | - Stephen A Wirkus
- School of Mathematical and Natural Sciences, Arizona State University, Glendale, AZ, USA
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9
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Yang Y, Yang Q, Luo S, Zhang Y, Lian C, He H, Zeng J, Zhang G. Comparative Analysis Reveals Novel Changes in Plasma Metabolites and Metabolomic Networks of Infants With Retinopathy of Prematurity. Invest Ophthalmol Vis Sci 2022; 63:28. [PMID: 35060995 PMCID: PMC8787637 DOI: 10.1167/iovs.63.1.28] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Purpose Advances in mass spectrometry have provided new insights into the role of metabolomics in the etiology of several diseases. Studies on retinopathy of prematurity (ROP), for example, overlooked the role of metabolic alterations in disease development. We employed comprehensive metabolic profiling and gold-standard metabolic analysis to explore major metabolites and metabolic pathways, which were significantly affected in early stages of pathogenesis toward ROP. Methods This was a multicenter, retrospective, matched-pair, case-control study. We collected plasma from 57 ROP cases and 57 strictly matched non-ROP controls. Non-targeted ultra-high-performance liquid chromatography-tandem mass spectroscopy (UPLC-MS/MS) was used to detect the metabolites. Machine learning was employed to reveal the most affected metabolites and pathways in ROP development. Results Compared with non-ROP controls, we found a significant metabolic perturbation in the plasma of ROP cases, which featured an increase in the levels of lipids, nucleotides, and carbohydrate metabolites and lower levels of peptides. Machine leaning enabled us to distinguish a cluster of metabolic pathways (glycometabolism, redox homeostasis, lipid metabolism, and arginine pathway) were strongly correlated with the development of ROP. Moreover, the severity of ROP was associated with the levels of creatinine and ribitol; also, overactivity of aerobic glycolysis and lipid metabolism was noted in the metabolic profile of ROP. Conclusions The results suggest a strong correlation between metabolic profiling and retinal neovascularization in ROP pathogenesis. These findings provide an insight into the identification of novel metabolic biomarkers for the diagnosis and prevention of ROP, but the clinical significance requires further validation.
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Affiliation(s)
- Yuhang Yang
- Shenzhen Eye Hospital, Shenzhen Key Ophthalmic Laboratory, The Second Affiliated Hospital of Jinan University, Shenzhen, Guangdong, China
| | - Qian Yang
- UCL Institute of Ophthalmology, University College London, London, United Kingdom
| | - Sisi Luo
- Shenzhen Key Prevention and Control Laboratory of Birth Defects Prevention and Control, Shenzhen Maternal and Child Health Hospital, The Affiliated Hospital of Southern Medical University, Shenzhen, Guangdong, China
| | - Yinsheng Zhang
- School of Management and E-Business, Zhejiang Gongshang University, Hangzhou, Zhejiang, China
| | - Chaohui Lian
- Shenzhen Key Prevention and Control Laboratory of Birth Defects Prevention and Control, Shenzhen Maternal and Child Health Hospital, The Affiliated Hospital of Southern Medical University, Shenzhen, Guangdong, China
| | - Honghui He
- Shenzhen Eye Hospital, Shenzhen Key Ophthalmic Laboratory, The Second Affiliated Hospital of Jinan University, Shenzhen, Guangdong, China
| | - Jian Zeng
- Shenzhen Eye Hospital, Shenzhen Key Ophthalmic Laboratory, The Second Affiliated Hospital of Jinan University, Shenzhen, Guangdong, China
| | - Guoming Zhang
- Shenzhen Eye Hospital, Shenzhen Key Ophthalmic Laboratory, The Second Affiliated Hospital of Jinan University, Shenzhen, Guangdong, China
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10
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Wang C, An Y, Xia Z, Zhou X, Li H, Song S, Ding L, Xia X. The neuroprotective effect of melatonin in glutamate excitotoxicity of R28 cells and mouse retinal ganglion cells. Front Endocrinol (Lausanne) 2022; 13:986131. [PMID: 36313740 PMCID: PMC9596792 DOI: 10.3389/fendo.2022.986131] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Accepted: 09/26/2022] [Indexed: 11/17/2022] Open
Abstract
Glaucoma is the leading cause of irreversible blindness. The progressive degeneration of retinal ganglion cells (RGCs) is the major characteristic of glaucoma. Even though the control of intraocular pressure could delay the loss of RGCs, current clinical treatments cannot protect them directly. The overactivation of N-methyl-D-aspartic acid (NMDA) receptors by excess glutamate (Glu) is among the important mechanisms of RGC death in glaucoma progression. Melatonin (MT) is an indole neuroendocrine hormone mainly secreted by the pineal gland. This study aimed to investigate the therapeutic effect of MT on glutamate excitotoxicity of mouse RGCs and R28 cells. The Glu-induced R28 cell excitotoxicity model and NMDA-induced retinal injury model were established. MT was applied to R28 cells and the vitreous cavity of mice by intravitreal injection. Cell counting kit-8 assay and propidium iodide/Hoechst were performed to evaluate cell viability. Reactive oxygen species and glutathione synthesis assays were used to detect the oxidative stress state of R28 cells. Retina immunofluorescence and hematoxylin and eosin staining were applied to assess RGC counts and retinal structure. Flash visual-evoked potential was performed to evaluate visual function in mice. RNA sequencing of the retina was performed to explore the underlying mechanisms of MT protection. Our results found that MT treatment could successfully protect R28 cells from Glu excitotoxicity and decrease reactive oxygen species. Also, MT rescued RGCs from NMDA-induced injury and protected visual function in mice. This study enriches the indications of MT in the treatment of glaucoma, providing practical research ideas for its comprehensive prevention and treatment.
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Affiliation(s)
- Chao Wang
- Eye Center of Xiangya Hospital, Central South University, Changsha, China
- Hunan Key Laboratory of Ophthalmology, Central South University, Changsha, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Yaqiong An
- Eye Center of Xiangya Hospital, Central South University, Changsha, China
- Hunan Key Laboratory of Ophthalmology, Central South University, Changsha, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Zhaohua Xia
- Eye Center of Xiangya Hospital, Central South University, Changsha, China
- Hunan Key Laboratory of Ophthalmology, Central South University, Changsha, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Xuezhi Zhou
- Eye Center of Xiangya Hospital, Central South University, Changsha, China
- Hunan Key Laboratory of Ophthalmology, Central South University, Changsha, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Haibo Li
- Eye Center of Xiangya Hospital, Central South University, Changsha, China
- Hunan Key Laboratory of Ophthalmology, Central South University, Changsha, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Shuang Song
- Department of Social Medicine and Health Management, Xiangya School of Public Health, Central South University, Changsha, China
| | - Lexi Ding
- Eye Center of Xiangya Hospital, Central South University, Changsha, China
- Hunan Key Laboratory of Ophthalmology, Central South University, Changsha, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
- *Correspondence: Xiaobo Xia, ; Lexi Ding,
| | - Xiaobo Xia
- Eye Center of Xiangya Hospital, Central South University, Changsha, China
- Hunan Key Laboratory of Ophthalmology, Central South University, Changsha, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
- *Correspondence: Xiaobo Xia, ; Lexi Ding,
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11
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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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12
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Du J, Zhu S, Lim RR, Chao JR. Proline metabolism and transport in retinal health and disease. Amino Acids 2021; 53:1789-1806. [PMID: 33871679 PMCID: PMC8054134 DOI: 10.1007/s00726-021-02981-1] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Accepted: 04/10/2021] [Indexed: 12/11/2022]
Abstract
The retina is one of the most energy-demanding tissues in the human body. Photoreceptors in the outer retina rely on nutrient support from the neighboring retinal pigment epithelium (RPE), a monolayer of epithelial cells that separate the retina and choroidal blood supply. RPE dysfunction or cell death can result in photoreceptor degeneration, leading to blindness in retinal degenerative diseases including some inherited retinal degenerations and age-related macular degeneration (AMD). In addition to having ready access to rich nutrients from blood, the RPE is also supplied with lactate from adjacent photoreceptors. Moreover, RPE can phagocytose lipid-rich outer segments for degradation and recycling on a daily basis. Recent studies show RPE cells prefer proline as a major metabolic substrate, and they are highly enriched for the proline transporter, SLC6A20. In contrast, dysfunctional or poorly differentiated RPE fails to utilize proline. RPE uses proline to fuel mitochondrial metabolism, synthesize amino acids, build the extracellular matrix, fight against oxidative stress, and sustain differentiation. Remarkably, the neural retina rarely imports proline directly, but it uptakes and utilizes intermediates and amino acids derived from proline catabolism in the RPE. Mutations of genes in proline metabolism are associated with retinal degenerative diseases, and proline supplementation is reported to improve RPE-initiated vision loss. This review will cover proline metabolism in RPE and highlight the importance of proline transport and utilization in maintaining retinal metabolism and health.
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Affiliation(s)
- Jianhai Du
- Department of Ophthalmology and Visual Sciences, West Virginia University, Morgantown, WV, 26506, USA. .,Department of Biochemistry, West Virginia University, Morgantown, WV, 26506, USA. .,One Medical Center Dr, WVU Eye Institute, PO Box 9193, Morgantown, WV, 26505, USA.
| | - Siyan Zhu
- Department of Ophthalmology and Visual Sciences, West Virginia University, Morgantown, WV, 26506, USA.,Department of Biochemistry, West Virginia University, Morgantown, WV, 26506, USA
| | - Rayne R Lim
- Department of Ophthalmology, University of Washington, Seattle, WA, 98109, USA
| | - Jennifer R Chao
- Department of Ophthalmology, University of Washington, Seattle, WA, 98109, USA
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13
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Pan WW, Wubben TJ, Besirli CG. 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] [MESH Headings] [Grants] [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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Affiliation(s)
- Warren W Pan
- Department of Ophthalmology and Visual Sciences, Kellogg Eye Center, University of Michigan, Ann Arbor, MI, USA
| | - Thomas J Wubben
- Department of Ophthalmology and Visual Sciences, Kellogg Eye Center, University of Michigan, Ann Arbor, MI, USA.
| | - Cagri G Besirli
- Department of Ophthalmology and Visual Sciences, Kellogg Eye Center, University of Michigan, Ann Arbor, MI, USA.
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14
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Weis SN, Souza JMF, Hoppe JB, Firmino M, Auer M, Ataii NN, da Silva LA, Gaelzer MM, Klein CP, Mól AR, de Lima CMR, Souza DO, Salbego CG, Ricart CAO, Fontes W, de Sousa MV. In-depth quantitative proteomic characterization of organotypic hippocampal slice culture reveals sex-specific differences in biochemical pathways. Sci Rep 2021; 11:2560. [PMID: 33510253 PMCID: PMC7844295 DOI: 10.1038/s41598-021-82016-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Accepted: 12/21/2020] [Indexed: 12/19/2022] Open
Abstract
Sex differences in the brain of mammals range from neuroarchitecture through cognition to cellular metabolism. The hippocampus, a structure mostly associated with learning and memory, presents high vulnerability to neurodegeneration and aging. Therefore, we explored basal sex-related differences in the proteome of organotypic hippocampal slice culture, a major in vitro model for studying the cellular and molecular mechanisms related to neurodegenerative disorders. Results suggest a greater prevalence of astrocytic metabolism in females and significant neuronal metabolism in males. The preference for glucose use in glycolysis, pentose phosphate pathway and glycogen metabolism in females and high abundance of mitochondrial respiration subunits in males support this idea. An overall upregulation of lipid metabolism was observed in females. Upregulation of proteins responsible for neuronal glutamate and GABA synthesis, along with synaptic associated proteins, were observed in males. In general, the significant spectrum of pathways known to predominate in neurons or astrocytes, together with the well-known neuronal and glial markers observed, revealed sex-specific metabolic differences in the hippocampus. TEM qualitative analysis might indicate a greater presence of mitochondria at CA1 synapses in females. These findings are crucial to a better understanding of how sex chromosomes can influence the physiology of cultured hippocampal slices and allow us to gain insights into distinct responses of males and females on neurological diseases that present a sex-biased incidence.
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Affiliation(s)
- Simone Nardin Weis
- Laboratory of Protein Chemistry and Biochemistry, Department of Cell Biology, Institute of Biology, University of Brasília, Brasília, DF, 70910-900, Brazil.
| | - Jaques Miranda F Souza
- Laboratory of Protein Chemistry and Biochemistry, Department of Cell Biology, Institute of Biology, University of Brasília, Brasília, DF, 70910-900, Brazil
| | - Juliana Bender Hoppe
- Department of Biochemistry, Federal University of Rio Grande do Sul, Porto Alegre, 90035-003, Brazil
| | - Marina Firmino
- Laboratory of Protein Chemistry and Biochemistry, Department of Cell Biology, Institute of Biology, University of Brasília, Brasília, DF, 70910-900, Brazil
| | - Manfred Auer
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, MS Donner, Berkeley, CA, 94720, USA
| | - Nassim N Ataii
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, MS Donner, Berkeley, CA, 94720, USA
| | - Leonardo Assis da Silva
- Laboratory of Electron Microscopy, Department of Cell Biology, Institute of Biological Sciences, University of Brasília, Brasília, DF, 70910-900, Brazil
| | | | - Caroline Peres Klein
- Department of Biochemistry, Federal University of Rio Grande do Sul, Porto Alegre, 90035-003, Brazil
| | - Alan R Mól
- Laboratory of Protein Chemistry and Biochemistry, Department of Cell Biology, Institute of Biology, University of Brasília, Brasília, DF, 70910-900, Brazil
| | - Consuelo M R de Lima
- Laboratory of Protein Chemistry and Biochemistry, Department of Cell Biology, Institute of Biology, University of Brasília, Brasília, DF, 70910-900, Brazil
| | - Diogo Onofre Souza
- Department of Biochemistry, Federal University of Rio Grande do Sul, Porto Alegre, 90035-003, Brazil
| | - Christianne G Salbego
- Department of Biochemistry, Federal University of Rio Grande do Sul, Porto Alegre, 90035-003, Brazil
| | - Carlos André O Ricart
- Laboratory of Protein Chemistry and Biochemistry, Department of Cell Biology, Institute of Biology, University of Brasília, Brasília, DF, 70910-900, Brazil
| | - Wagner Fontes
- Laboratory of Protein Chemistry and Biochemistry, Department of Cell Biology, Institute of Biology, University of Brasília, Brasília, DF, 70910-900, Brazil
| | - Marcelo Valle de Sousa
- Laboratory of Protein Chemistry and Biochemistry, Department of Cell Biology, Institute of Biology, University of Brasília, Brasília, DF, 70910-900, Brazil
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15
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The innate immune system in diabetic retinopathy. Prog Retin Eye Res 2021; 84:100940. [PMID: 33429059 DOI: 10.1016/j.preteyeres.2021.100940] [Citation(s) in RCA: 49] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 12/24/2020] [Accepted: 01/03/2021] [Indexed: 12/20/2022]
Abstract
The prevalence of diabetes has been rising steadily in the past half-century, along with the burden of its associated complications, including diabetic retinopathy (DR). DR is currently the most common cause of vision loss in working-age adults in the United States. Historically, DR has been diagnosed and classified clinically based on what is visible by fundoscopy; that is vasculature alterations. However, recent technological advances have confirmed pathology of the neuroretina prior to any detectable vascular changes. These, coupled with molecular studies, and the positive impact of anti-inflammatory therapeutics in DR patients have highlighted the central involvement of the innate immune system. Reminiscent of the systemic impact of diabetes, immune dysregulation has become increasingly identified as a key element of the pathophysiology of DR by interfering with normal homeostatic systems. This review uses the growing body of literature across various model systems to demonstrate the clear involvement of all three pillars of the immune system: immune-competent cells, mediators, and the complement system. It also demonstrates how the relative contribution of each of these requires more extensive analysis, including in human tissues over the continuum of disease progression. Finally, although this review demonstrates how the complex interactions of the immune system pose many more questions than answers, the intimately connected nature of the three pillars of the immune system may also point to possible new targets to reverse or even halt reverse retinopathy.
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16
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Zhang R, Engel AL, Wang Y, Li B, Shen W, Gillies MC, Chao JR, Du J. Inhibition of Mitochondrial Respiration Impairs Nutrient Consumption and Metabolite Transport in Human Retinal Pigment Epithelium. J Proteome Res 2020; 20:909-922. [PMID: 32975122 DOI: 10.1021/acs.jproteome.0c00690] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Mitochondrial respiration in mammalian cells not only generates ATP to meet their own energy needs but also couples with biosynthetic pathways to produce metabolites that can be exported to support neighboring cells. However, how defects in mitochondrial respiration influence these biosynthetic and exporting pathways remains poorly understood. Mitochondrial dysfunction in retinal pigment epithelium (RPE) cells is an emerging contributor to the death of their neighboring photoreceptors in degenerative retinal diseases including age-related macular degeneration. In this study, we used targeted-metabolomics and 13C tracing to investigate how inhibition of mitochondrial respiration influences the intracellular and extracellular metabolome. We found inhibition of mitochondrial respiration strikingly influenced both the intracellular and extracellular metabolome in primary RPE cells. Intriguingly, the extracellular metabolic changes sensitively reflected the intracellular changes. These changes included substantially enhanced glucose consumption and lactate production; reduced release of pyruvate, citrate, and ketone bodies; and massive accumulation of multiple amino acids and nucleosides. In conclusion, these findings reveal a metabolic signature of nutrient consumption and release in mitochondrial dysfunction in RPE cells. Testing medium metabolites provides a sensitive and noninvasive method to assess mitochondrial function in nutrient utilization and transport.
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Affiliation(s)
- Rui Zhang
- Department of Ophthalmology, West Virginia University, Morgantown, West Virginia 26506, United States.,Department of Biochemistry, West Virginia University, Morgantown, West Virginia 26506, United States.,Save Sight Institute, Sydney Medical School, University of Sydney, Sydney, NSW 2000, Australia
| | - Abbi L Engel
- Department of Ophthalmology, University of Washington, Seattle, Washington 98109, United States
| | - Yekai Wang
- Department of Ophthalmology, West Virginia University, Morgantown, West Virginia 26506, United States.,Department of Biochemistry, West Virginia University, Morgantown, West Virginia 26506, United States
| | - Bo Li
- Department of Ophthalmology, West Virginia University, Morgantown, West Virginia 26506, United States.,Department of Biochemistry, West Virginia University, Morgantown, West Virginia 26506, United States
| | - Weiyong Shen
- Save Sight Institute, Sydney Medical School, University of Sydney, Sydney, NSW 2000, Australia
| | - Mark C Gillies
- Save Sight Institute, Sydney Medical School, University of Sydney, Sydney, NSW 2000, Australia
| | - Jennifer R Chao
- Department of Ophthalmology, University of Washington, Seattle, Washington 98109, United States
| | - Jianhai Du
- Department of Ophthalmology, West Virginia University, Morgantown, West Virginia 26506, United States.,Department of Biochemistry, West Virginia University, Morgantown, West Virginia 26506, United States
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17
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Buchanan JL, Taylor EB. Mitochondrial Pyruvate Carrier Function in Health and Disease across the Lifespan. Biomolecules 2020; 10:biom10081162. [PMID: 32784379 PMCID: PMC7464753 DOI: 10.3390/biom10081162] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2020] [Revised: 08/05/2020] [Accepted: 08/06/2020] [Indexed: 12/25/2022] Open
Abstract
As a nodal mediator of pyruvate metabolism, the mitochondrial pyruvate carrier (MPC) plays a pivotal role in many physiological and pathological processes across the human lifespan, from embryonic development to aging-associated neurodegeneration. Emerging research highlights the importance of the MPC in diverse conditions, such as immune cell activation, cancer cell stemness, and dopamine production in Parkinson’s disease models. Whether MPC function ameliorates or contributes to disease is highly specific to tissue and cell type. Cell- and tissue-specific differences in MPC content and activity suggest that MPC function is tightly regulated as a mechanism of metabolic, cellular, and organismal control. Accordingly, recent studies on cancer and diabetes have identified protein–protein interactions, post-translational processes, and transcriptional factors that modulate MPC function. This growing body of literature demonstrates that the MPC and other mitochondrial carriers comprise a versatile and dynamic network undergirding the metabolism of health and disease.
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Affiliation(s)
- Jane L. Buchanan
- Department of Molecular Physiology and Biophysics, University of Iowa Carver College of Medicine, Iowa City, IA 52240, USA;
| | - Eric B. Taylor
- Department of Molecular Physiology and Biophysics, University of Iowa Carver College of Medicine, Iowa City, IA 52240, USA;
- Holden Comprehensive Cancer Center, University of Iowa Carver College of Medicine, Iowa City, IA 52240, USA
- Fraternal Order of Eagles Diabetes Research Center (FOEDRC), University of Iowa Carver College of Medicine, Iowa City, IA 52240, USA
- Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine, Iowa City, IA 52240, USA
- Pappajohn Biomedical Institute, University of Iowa Carver College of Medicine, Iowa City, IA 52240, USA
- Correspondence:
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18
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Sinha T, Naash MI, Al-Ubaidi MR. The Symbiotic Relationship between the Neural Retina and Retinal Pigment Epithelium Is Supported by Utilizing Differential Metabolic Pathways. iScience 2020; 23:101004. [PMID: 32252018 PMCID: PMC7132098 DOI: 10.1016/j.isci.2020.101004] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Revised: 01/09/2020] [Accepted: 03/18/2020] [Indexed: 12/13/2022] Open
Abstract
The neural retina and retinal pigment epithelium (RPE) maintain a symbiotic metabolic relationship, disruption of which leads to debilitating vision loss. The current study was undertaken to identify the differences in the steady-state metabolite levels and the pathways functioning between bona fide neural retina and RPE. Global metabolomics and cluster analyses identified 650 metabolites differentially modulated between the murine neural retina and RPE. Of these, 387 and 163 were higher in the RPE and the neural retina, respectively. Further analysis coupled with transcript and protein level investigations revealed that under normal physiological conditions, the RPE utilizes the pentose phosphate (>3-fold in RPE), serine (>10-fold in RPE), and sphingomyelin biosynthesis (>5-fold in RPE) pathways. Conversely, the neural retina relied mostly on glycolysis. These results show how the RPE and the neural retina have acquired an efficient, complementary and metabolically diverse symbiotic niche to support each other's distinct functions.
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Affiliation(s)
- Tirthankar Sinha
- Department of Biomedical Engineering, University of Houston, Houston, TX 77204, USA
| | - Muna I Naash
- Department of Biomedical Engineering, University of Houston, Houston, TX 77204, USA.
| | - Muayyad R Al-Ubaidi
- Department of Biomedical Engineering, University of Houston, Houston, TX 77204, USA.
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19
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Xu R, Ritz BK, Wang Y, Huang J, Zhao C, Gong K, Liu X, Du J. The retina and retinal pigment epithelium differ in nitrogen metabolism and are metabolically connected. J Biol Chem 2020; 295:2324-2335. [PMID: 31953322 DOI: 10.1074/jbc.ra119.011727] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 01/15/2020] [Indexed: 01/07/2023] Open
Abstract
Defects in energy metabolism in either the retina or the immediately adjacent retinal pigment epithelium (RPE) underlie retinal degeneration, but the metabolic dependence between retina and RPE remains unclear. Nitrogen-containing metabolites such as amino acids are essential for energy metabolism. Here, we found that 15N-labeled ammonium is predominantly assimilated into glutamine in both the retina and RPE/choroid ex vivo [15N]Ammonium tracing in vivo show that, like the brain, the retina can synthesize asparagine from ammonium, but RPE/choroid and the liver cannot. However, unless present at toxic concentrations, ammonium cannot be recycled into glutamate in the retina and RPE/choroid. Tracing with 15N-labeled amino acids show that the retina predominantly uses aspartate transaminase for de novo synthesis of glutamate, glutamine, and aspartate, whereas RPE uses multiple transaminases to utilize and synthesize amino acids. Retina consumes more leucine than RPE, but little leucine is catabolized. The synthesis of serine and glycine is active in RPE but limited in the retina. RPE, but not the retina, uses alanine as mitochondrial substrates through mitochondrial pyruvate carrier. However, when the mitochondrial pyruvate carrier is inhibited, alanine may directly enter the retinal mitochondria but not those of RPE. In conclusion, our results demonstrate that the retina and RPE differ in nitrogen metabolism and highlight that the RPE supports retinal metabolism through active amino acid metabolism.
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Affiliation(s)
- Rong Xu
- Central Laboratory, Affiliated Hospital of Yangzhou University, Yangzhou University, Yangzhou, 225012 China; Department of Ophthalmology, West Virginia University, Morgantown, West Virginia 26506; Department of Biochemistry, West Virginia University, Morgantown, West Virginia 26506
| | - Brianna K Ritz
- Department of Ophthalmology, West Virginia University, Morgantown, West Virginia 26506; Department of Biochemistry, West Virginia University, Morgantown, West Virginia 26506
| | - Yekai Wang
- Department of Ophthalmology, West Virginia University, Morgantown, West Virginia 26506; Department of Biochemistry, West Virginia University, Morgantown, West Virginia 26506
| | - Jiancheng Huang
- Department of Ophthalmology, West Virginia University, Morgantown, West Virginia 26506; Department of Biochemistry, West Virginia University, Morgantown, West Virginia 26506; Eye Institute, Eye and ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, 200433 China
| | - Chen Zhao
- Eye Institute, Eye and ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, 200433 China
| | - Kaizheng Gong
- Department of Cardiology, the Affiliated Hospital of Yangzhou University, Yangzhou University, Yangzhou, 225012 China
| | - Xinnong Liu
- Department of General Surgery, Affiliated Hospital of Yangzhou University, Yangzhou University, Yangzhou, 225012; Department of Cardiology, the Affiliated Hospital of Yangzhou University, Yangzhou University, Yangzhou, 225012 China.
| | - Jianhai Du
- Department of Ophthalmology, West Virginia University, Morgantown, West Virginia 26506; Department of Biochemistry, West Virginia University, Morgantown, West Virginia 26506.
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20
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Hutto RA, Bisbach CM, Abbas F, Brock DC, Cleghorn WM, Parker ED, Bauer BH, Ge W, Vinberg F, Hurley JB, Brockerhoff SE. Increasing Ca 2+ in photoreceptor mitochondria alters metabolites, accelerates photoresponse recovery, and reveals adaptations to mitochondrial stress. Cell Death Differ 2019; 27:1067-1085. [PMID: 31371786 PMCID: PMC7206026 DOI: 10.1038/s41418-019-0398-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 06/19/2019] [Accepted: 07/11/2019] [Indexed: 11/09/2022] Open
Abstract
Photoreceptors are specialized neurons that rely on Ca2+ to regulate phototransduction and neurotransmission. Photoreceptor dysfunction and degeneration occur when intracellular Ca2+ homeostasis is disrupted. Ca2+ homeostasis is maintained partly by mitochondrial Ca2+ uptake through the mitochondrial Ca2+ uniporter (MCU), which can influence cytosolic Ca2+ signals, stimulate energy production, and trigger apoptosis. Here we discovered that zebrafish cone photoreceptors express unusually low levels of MCU. We expected that this would be important to prevent mitochondrial Ca2+ overload and consequent cone degeneration. To test this hypothesis, we generated a cone-specific model of MCU overexpression. Surprisingly, we found that cones tolerate MCU overexpression, surviving elevated mitochondrial Ca2+ and disruptions to mitochondrial ultrastructure until late adulthood. We exploited the survival of MCU overexpressing cones to additionally demonstrate that mitochondrial Ca2+ uptake alters the distributions of citric acid cycle intermediates and accelerates recovery kinetics of the cone response to light. Cones adapt to mitochondrial Ca2+ stress by decreasing MICU3, an enhancer of MCU-mediated Ca2+ uptake, and selectively transporting damaged mitochondria away from the ellipsoid toward the synapse. Our findings demonstrate how mitochondrial Ca2+ can influence physiological and metabolic processes in cones and highlight the remarkable ability of cone photoreceptors to adapt to mitochondrial stress.
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Affiliation(s)
- Rachel A Hutto
- Biochemistry Department, University of Washington, Seattle, WA, 98109, USA
| | - Celia M Bisbach
- Biochemistry Department, University of Washington, Seattle, WA, 98109, USA
| | - Fatima Abbas
- John A. Moran Eye Center, University of Utah, Salt Lake City, UT, 84132, USA
| | - Daniel C Brock
- Biochemistry Department, University of Washington, Seattle, WA, 98109, USA
| | - Whitney M Cleghorn
- Biochemistry Department, University of Washington, Seattle, WA, 98109, USA
| | - Edward D Parker
- Opthalmology Department, University of Washington, Seattle, WA, 98109, USA
| | - Benjamin H Bauer
- Biochemistry Department, University of Washington, Seattle, WA, 98109, USA
| | - William Ge
- Biochemistry Department, University of Washington, Seattle, WA, 98109, USA
| | - Frans Vinberg
- John A. Moran Eye Center, University of Utah, Salt Lake City, UT, 84132, USA
| | - James B Hurley
- Biochemistry Department, University of Washington, Seattle, WA, 98109, USA.,Opthalmology Department, University of Washington, Seattle, WA, 98109, USA
| | - Susan E Brockerhoff
- Biochemistry Department, University of Washington, Seattle, WA, 98109, USA. .,Opthalmology Department, University of Washington, Seattle, WA, 98109, USA.
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21
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Yam M, Engel AL, Wang Y, Zhu S, Hauer A, Zhang R, Lohner D, Huang J, Dinterman M, Zhao C, Chao JR, Du J. Proline mediates metabolic communication between retinal pigment epithelial cells and the retina. J Biol Chem 2019; 294:10278-10289. [PMID: 31110046 PMCID: PMC6664195 DOI: 10.1074/jbc.ra119.007983] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Revised: 05/16/2019] [Indexed: 01/16/2023] Open
Abstract
The retinal pigment epithelium (RPE) is a monolayer of pigmented cells between the choroid and the retina. RPE dysfunction underlies many retinal degenerative diseases, including age-related macular degeneration, the leading cause of age-related blindness. To perform its various functions in nutrient transport, phagocytosis of the outer segment, and cytokine secretion, the RPE relies on an active energy metabolism. We previously reported that human RPE cells prefer proline as a nutrient and transport proline-derived metabolites to the apical, or retinal, side. In this study, we investigated how RPE utilizes proline in vivo and why proline is a preferred substrate. By using [13C]proline labeling both ex vivo and in vivo, we found that the retina rarely uses proline directly, whereas the RPE utilizes it at a high rate, exporting proline-derived mitochondrial intermediates for use by the retina. We observed that in primary human RPE cell culture, proline is the only amino acid whose uptake increases with cellular maturity. In human RPE, proline was sufficient to stimulate de novo serine synthesis, increase reductive carboxylation, and protect against oxidative damage. Blocking proline catabolism in RPE impaired glucose metabolism and GSH production. Notably, in an acute model of RPE-induced retinal degeneration, dietary proline improved visual function. In conclusion, proline is an important nutrient that supports RPE metabolism and the metabolic demand of the retina.
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Affiliation(s)
- Michelle Yam
- From the Departments of Ophthalmology and
- Biochemistry, West Virginia University, Morgantown, West Virginia 26506
| | - Abbi L Engel
- the Department of Ophthalmology, University of Washington, Seattle, Washington 98109
| | - Yekai Wang
- From the Departments of Ophthalmology and
- Biochemistry, West Virginia University, Morgantown, West Virginia 26506
| | - Siyan Zhu
- From the Departments of Ophthalmology and
- Biochemistry, West Virginia University, Morgantown, West Virginia 26506
| | - Allison Hauer
- From the Departments of Ophthalmology and
- Biochemistry, West Virginia University, Morgantown, West Virginia 26506
| | - Rui Zhang
- From the Departments of Ophthalmology and
- the Save Sight Institute, University of Sydney, 8 Macquarie Street, Sydney, New South Wales 2000, Australia
| | - Daniel Lohner
- From the Departments of Ophthalmology and
- Biochemistry, West Virginia University, Morgantown, West Virginia 26506
| | - Jiancheng Huang
- From the Departments of Ophthalmology and
- the Eye Institute, Eye and ENT Hospital, Shanghai Medical College, Fudan University, Shanghai 200031, China, and
- the Department of Ophthalmology, State Key Laboratory of Reproductive Medicine, First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China
| | - Marlee Dinterman
- From the Departments of Ophthalmology and
- Biochemistry, West Virginia University, Morgantown, West Virginia 26506
| | - Chen Zhao
- the Eye Institute, Eye and ENT Hospital, Shanghai Medical College, Fudan University, Shanghai 200031, China, and
| | - Jennifer R Chao
- the Department of Ophthalmology, University of Washington, Seattle, Washington 98109,
| | - Jianhai Du
- From the Departments of Ophthalmology and
- Biochemistry, West Virginia University, Morgantown, West Virginia 26506
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22
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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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23
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Abstract
Cellular coenzymes including coenzyme A (CoA), acetyl coenzyme A (acetyl-CoA), coenzymes of redox reactions and of energy, and antioxidants mediate biochemical reactions fundamental to the functioning of all living cells. The redox coenzymes include NAD+ (oxidized nicotinamide adenine dinucleotide), NADH (reduced nicotinamide adenine dinucleotide), NADP+ (oxidized nicotinamide adenine dinucleotide phosphate), and NADPH (reduced nicotinamide adenine dinucleotide phosphate); the energy coenzymes include ATP (adenosine triphosphate), ADP (adenosine diphosphate), and AMP (adenosine monophosphate); and the antioxidants include GSSG (oxidized glutathione) and GSH (reduced glutathione). Their measurement is important to better understand cellular metabolism. Recent advances have pushed the limit of metabolite quantitation using NMR methods to an unprecedented level, which offer a new avenue for analysis of the coenzymes and antioxidants. Unlike the conventional enzyme assays, which need separate protocols for analysis, a simple 1D 1H NMR experiment enables analysis of all these molecular species in one step. In this chapter, we describe protocols for their identification and quantitation in tissue and whole blood using NMR spectroscopy.
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24
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Ola MS, LaNoue KF. Molecular basis for increased lactate formation in the Müller glial cells of retina. Brain Res Bull 2018; 144:158-163. [PMID: 30503222 DOI: 10.1016/j.brainresbull.2018.11.023] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 10/22/2018] [Accepted: 11/27/2018] [Indexed: 10/27/2022]
Abstract
Müller glial cells are highly metabolic active cells that compensate for the high energy demand of retinal neurons. It has been believed that glucose provides the energy needs by the complete oxidation within Müller cells. However, numerous studies indicated that glial cells convert the majority of glucose to lactate, which may serve as an energy source for neurons. It is still not well understood why within glia, glucose is not completely oxidized under aerobic glycolysis conditions. The aspartate glutamate carrier (AGC) is a major component of the malate-aspartate shuttle (MAS) responsible for transporting the reducing equivalent of glycolysis to the mitochondria for the complete oxidation of glucose. Here, we report the absence of AGC within Müller glial cells which impairs the ability to oxidize glucose. We investigated the expression and localization of AGC and its isoforms (aralar and citrin) in the intact rat retina. We also analyzed the expression and regulation of AGC and its metabolic activity within cultured Müller cells (TR-MUL). The results suggest that AGC and its isoforms seem to be neuronal, with no or low expression within Müller cells of the intact retina. The study of cultured Müller cells suggests a very low expression of AGC and a decreased metabolic activity of the carrier especially under cell differentiation conditions due to low serum and hydrocortisone treatments. Thus, these data give a molecular explanation of increased levels of lactate formation due to a lack of AGC in the retina by Müller glial cells.
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Affiliation(s)
- Mohammad Shamsul Ola
- Department of Biochemistry, College of Science, King Saud University, Riyadh, Saudi Arabia.
| | - Kathryn F LaNoue
- Department of Cellular and Molecular Physiology, College of Medicine, Pennsylvania State University, Hershey, PA 17033, United States
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25
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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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26
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Yellen G. Fueling thought: Management of glycolysis and oxidative phosphorylation in neuronal metabolism. J Cell Biol 2018; 217:2235-2246. [PMID: 29752396 PMCID: PMC6028533 DOI: 10.1083/jcb.201803152] [Citation(s) in RCA: 213] [Impact Index Per Article: 35.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Revised: 04/30/2018] [Accepted: 05/02/2018] [Indexed: 01/02/2023] Open
Abstract
Yellen reviews how cellular metabolism responds acutely to the intense energy requirements of neurons when they are stimulated. The brain’s energy demands are remarkable both in their intensity and in their moment-to-moment dynamic range. This perspective considers the evidence for Warburg-like aerobic glycolysis during the transient metabolic response of the brain to acute activation, and it particularly addresses the cellular mechanisms that underlie this metabolic response. The temporary uncoupling between glycolysis and oxidative phosphorylation led to the proposal of an astrocyte-to-neuron lactate shuttle whereby during stimulation, lactate produced by increased glycolysis in astrocytes is taken up by neurons as their primary energy source. However, direct evidence for this idea is lacking, and evidence rather supports that neurons have the capacity to increase their own glycolysis in response to stimulation; furthermore, neurons may export rather than import lactate in response to stimulation. The possible cellular mechanisms for invoking metabolic resupply of energy in neurons are also discussed, in particular the roles of feedback signaling via adenosine diphosphate and feedforward signaling by calcium ions.
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Affiliation(s)
- Gary Yellen
- Department of Neurobiology, Harvard Medical School, Boston, MA
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27
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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: 238] [Impact Index Per Article: 34.0] [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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28
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Bataglini C, Rezende DGL, Primo MA, Gomes CRG, Pedrosa MMD, Godoi VAF. Glutamine dipeptide and cortisol change the liver glucose metabolism and reduce the severity of insulin-induced hypoglycaemia in untreated T1DM Swiss mice. Arch Physiol Biochem 2017; 123:134-144. [PMID: 28263096 DOI: 10.1080/13813455.2016.1273364] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
CONTEXT Glutamine is conditionally essential in type 1 diabetes mellitus, and might be useful to counteract hypoglycaemia. OBJECTIVE To investigate the systemic and hepatic effects of counter-regulatory hormones and glutamine dipeptide (GDP) during hypoglycemic episodes. MATERIALS AND METHODS Diabetic Swiss mice made hypoglycaemic by insulin injection (1 U/kg) were given counter-regulatory hormones and/or GDP. Sixty minutes later, liver histology, liver glucose metabolism and plasma were assessed. RESULTS Combined, cortisol and GDP improved the hypoglycemic profile. During liver perfusion, gluconeogenesis was possibly the major pathway leading to glucose release. Perfusion with gluconeogenic precursors after glycogen depletion by adrenaline increased liver glucose and urea release. DISCUSSION The less severe hypoglycaemia could result from cortisol stimulating periportal gluconeogenesis and GDP inhibiting pericentral glycogenolysis, both favouring liver glucose release. CONCLUSIONS At least some benefits of GDP and cortisol during hypoglycaemia came from their hepatic actions, and their use in diabetic patients should be explored.
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Affiliation(s)
- Camila Bataglini
- a Program of Graduate Studies in Biological Sciences, State University of Maringá , Maringá , Brazil
| | - Diego G L Rezende
- b Undergraduation in Physical Education, State University of Maringá , Maringá , Brazil
| | - Marcos A Primo
- b Undergraduation in Physical Education, State University of Maringá , Maringá , Brazil
| | - Célia R G Gomes
- c Department of Morphological Sciences , State University of Maringá , Maringá , Brazil , and
| | - Maria M D Pedrosa
- d Department of Physiological Sciences , State University of Maringá , Maringá , Brazil
| | - Vilma A F Godoi
- d Department of Physiological Sciences , State University of Maringá , Maringá , Brazil
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29
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Mitochondria Maintain Distinct Ca 2+ Pools in Cone Photoreceptors. J Neurosci 2017; 37:2061-2072. [PMID: 28115482 DOI: 10.1523/jneurosci.2689-16.2017] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Revised: 01/10/2017] [Accepted: 01/12/2017] [Indexed: 01/01/2023] Open
Abstract
Ca2+ ions have distinct roles in the outer segment, cell body, and synaptic terminal of photoreceptors. We tested the hypothesis that distinct Ca2+ domains are maintained by Ca2+ uptake into mitochondria. Serial block face scanning electron microscopy of zebrafish cones revealed that nearly 100 mitochondria cluster at the apical side of the inner segment, directly below the outer segment. The endoplasmic reticulum surrounds the basal and lateral surfaces of this cluster, but does not reach the apical surface or penetrate into the cluster. Using genetically encoded Ca2+ sensors, we found that mitochondria take up Ca2+ when it accumulates either in the cone cell body or outer segment. Blocking mitochondrial Ca2+ uniporter activity compromises the ability of mitochondria to maintain distinct Ca2+ domains. Together, our findings indicate that mitochondria can modulate subcellular functional specialization in photoreceptors.SIGNIFICANCE STATEMENT Ca2+ homeostasis is essential for the survival and function of retinal photoreceptors. Separate pools of Ca2+ regulate phototransduction in the outer segment, metabolism in the cell body, and neurotransmitter release at the synaptic terminal. We investigated the role of mitochondria in compartmentalization of Ca2+ We found that mitochondria form a dense cluster that acts as a diffusion barrier between the outer segment and cell body. The cluster is surprisingly only partially surrounded by the endoplasmic reticulum, a key mediator of mitochondrial Ca2+ uptake. Blocking the uptake of Ca2+ by mitochondria causes redistribution of Ca2+ throughout the cell. Our results show that mitochondrial Ca2+ uptake in photoreceptors is complex and plays an essential role in normal function.
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30
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Brockerhoff SE. Genome Editing to Study Ca 2+ Homeostasis in Zebrafish Cone Photoreceptors. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 1016:91-100. [PMID: 29130155 DOI: 10.1007/978-3-319-63904-8_5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Photoreceptors are specialized sensory neurons with unique biological features. Phototransduction is well understood due in part to the exclusive expression and function of the molecular components of this cascade. Many other processes are less well understood, but also extremely important for understanding photoreceptor function and for treating disease. One example is the role of Ca2+ in the cell body and overall compartmentalization and regulation of Ca2+ within the cell. The recent development of CRISPR/Cas9 genome editing techniques has made it possible to rapidly and cheaply alter specific genes. This will help to define the biological function of elusive processes that have been more challenging to study. CRISPR/Cas9 has been optimized in many systems including zebrafish, which already has some distinct advantages for studying photoreceptor biology and function. These new genome editing technologies and the continued use of the zebrafish model system will help advance our understanding of important understudied aspects of photoreceptor biology.
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Affiliation(s)
- Susan E Brockerhoff
- Departments of Biochemistry and Ophthalmology, University of Washington, UW Medicine, 750 Republican St, Box 358058, Seattle, WA, 98109, USA.
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31
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Reductive carboxylation is a major metabolic pathway in the retinal pigment epithelium. Proc Natl Acad Sci U S A 2016; 113:14710-14715. [PMID: 27911769 DOI: 10.1073/pnas.1604572113] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The retinal pigment epithelium (RPE) is a monolayer of pigmented cells that requires an active metabolism to maintain outer retinal homeostasis and compensate for oxidative stress. Using 13C metabolic flux analysis in human RPE cells, we found that RPE has an exceptionally high capacity for reductive carboxylation, a metabolic pathway that has recently garnered significant interest because of its role in cancer cell survival. The capacity for reductive carboxylation in RPE exceeds that of all other cells tested, including retina, neural tissue, glial cells, and a cancer cell line. Loss of reductive carboxylation disrupts redox balance and increases RPE sensitivity to oxidative damage, suggesting that deficiencies of reductive carboxylation may contribute to RPE cell death. Supporting reductive carboxylation by supplementation with an NAD+ precursor or its substrate α-ketoglutarate or treatment with a poly(ADP ribose) polymerase inhibitor protects reductive carboxylation and RPE viability from excessive oxidative stress. The ability of these treatments to rescue RPE could be the basis for an effective strategy to treat blinding diseases caused by RPE dysfunction.
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32
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Zhang L, Du J, Justus S, Hsu CW, Bonet-Ponce L, Wu WH, Tsai YT, Wu WP, Jia Y, Duong JK, Mahajan VB, Lin CS, Wang S, Hurley JB, Tsang SH. Reprogramming metabolism by targeting sirtuin 6 attenuates retinal degeneration. J Clin Invest 2016; 126:4659-4673. [PMID: 27841758 DOI: 10.1172/jci86905] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Accepted: 10/06/2016] [Indexed: 12/16/2022] Open
Abstract
Retinitis pigmentosa (RP) encompasses a diverse group of Mendelian disorders leading to progressive degeneration of rods and then cones. For reasons that remain unclear, diseased RP photoreceptors begin to deteriorate, eventually leading to cell death and, consequently, loss of vision. Here, we have hypothesized that RP associated with mutations in phosphodiesterase-6 (PDE6) provokes a metabolic aberration in rod cells that promotes the pathological consequences of elevated cGMP and Ca2+, which are induced by the Pde6 mutation. Inhibition of sirtuin 6 (SIRT6), a histone deacetylase repressor of glycolytic flux, reprogrammed rods into perpetual glycolysis, thereby driving the accumulation of biosynthetic intermediates, improving outer segment (OS) length, enhancing photoreceptor survival, and preserving vision. In mouse retinae lacking Sirt6, effectors of glycolytic flux were dramatically increased, leading to upregulation of key intermediates in glycolysis, TCA cycle, and glutaminolysis. Both transgenic and AAV2/8 gene therapy-mediated ablation of Sirt6 in rods provided electrophysiological and anatomic rescue of both rod and cone photoreceptors in a preclinical model of RP. Due to the extensive network of downstream effectors of Sirt6, this study motivates further research into the role that these pathways play in retinal degeneration. Because reprogramming metabolism by enhancing glycolysis is not gene specific, this strategy may be applicable to a wide range of neurodegenerative disorders.
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33
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Contreras L, Ramirez L, Du J, Hurley JB, Satrústegui J, de la Villa P. Deficient glucose and glutamine metabolism in Aralar/AGC1/Slc25a12 knockout mice contributes to altered visual function. Mol Vis 2016; 22:1198-1212. [PMID: 27746674 PMCID: PMC5063090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Accepted: 10/10/2016] [Indexed: 11/10/2022] Open
Abstract
PURPOSE To characterize the vision phenotype of mice lacking Aralar/AGC1/Slc25a12, the mitochondrial aspartate-glutamate carrier mutated in global cerebral hypomyelination (OMIM 612949). METHODS We tested overnight dark-adapted control and aralar-deficient mice for the standard full electroretinogram (ERG) response. The metabolic stress of dark-adaptation was reduced by 5 min illumination after which the ERG response was monitored in darkness. We used the electrical response to two identical saturating light flashes (paired-flash stimulation) to isolate the inner retina and photoreceptor responses. Retinal morphology was examined with hematoxylin and eosin staining, immunohistochemistry of antibodies against retinal cells, and 4',6-diamidino-2-phenylindole (DAPI) labeling. RESULTS Aralar plays a pivotal role in retina metabolism as aralar provides de novo synthesis pathway for glutamine, protects glutamate from oxidation, and is required for efficient glucose oxidative metabolism. Aralar-deficient mice are not blind as their retinas have light-evoked activity. However, we report an approximate 50% decrease in the ERG amplitude response in the light-evoked activity of dark-adapted retinas from aralar-deficient mice, in spite of normal retina histology. The defective response is partly reversed by exposure to a brief illumination period, which lowers the metabolic stress of dark-adaptation. The metabolic stress and ERG alteration takes place primarily in photoreceptors, but the response to two flashes applied in fast succession also revealed an alteration in synaptic transmission consistent with an imbalance of glutamate and an energy deficit in the inner retina neurons. CONCLUSIONS We propose that compromised glucose oxidation and altered glutamine and glutamate metabolism in the absence of aralar are responsible for the phenotype reported.
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Affiliation(s)
- Laura Contreras
- Centro de Biología Molecular Severo Ochoa CSIC-UAM, CI.B.E.R. de Enfermedades Raras, Instituto de Investigación Sanitaria Fundación Jiménez Díaz, Universidad Autónoma de Madrid, Madrid, Spain
| | - Laura Ramirez
- Department of Systems Biology, University of Alcalá, Alcalá de Henares, Spain
| | - Jianhai Du
- Department of Biochemistry, University of Washington, Seattle, WA.,Department of Ophthalmology, University of Washington, Seattle, WA
| | - James B. Hurley
- Department of Biochemistry, University of Washington, Seattle, WA.,Department of Ophthalmology, University of Washington, Seattle, WA
| | - Jorgina Satrústegui
- Centro de Biología Molecular Severo Ochoa CSIC-UAM, CI.B.E.R. de Enfermedades Raras, Instituto de Investigación Sanitaria Fundación Jiménez Díaz, Universidad Autónoma de Madrid, Madrid, Spain
| | - Pedro de la Villa
- Department of Systems Biology, University of Alcalá, Alcalá de Henares, Spain
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34
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Bolinger MT, Antonetti DA. Moving Past Anti-VEGF: Novel Therapies for Treating Diabetic Retinopathy. Int J Mol Sci 2016; 17:E1498. [PMID: 27618014 PMCID: PMC5037775 DOI: 10.3390/ijms17091498] [Citation(s) in RCA: 76] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Revised: 08/22/2016] [Accepted: 08/30/2016] [Indexed: 12/25/2022] Open
Abstract
Diabetic retinopathy is the leading cause of blindness in working age adults, and is projected to be a significant future health concern due to the rising incidence of diabetes. The recent advent of anti-vascular endothelial growth factor (VEGF) antibodies has revolutionized the treatment of diabetic retinopathy but a significant subset of patients fail to respond to treatment. Accumulating evidence indicates that inflammatory cytokines and chemokines other than VEGF may contribute to the disease process. The current review examines the presence of non-VEGF cytokines in the eyes of patients with diabetic retinopathy and highlights mechanistic pathways in relevant animal models. Finally, novel drug targets including components of the kinin-kallikrein system and emerging treatments such as anti-HPTP (human protein tyrosine phosphatase) β antibodies are discussed. Recognition of non-VEGF contributions to disease pathogenesis may lead to novel therapeutics to enhance existing treatments for patients who do not respond to anti-VEGF therapies.
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Affiliation(s)
- Mark T Bolinger
- Departments of Ophthalmology and Visual Sciences, Kellogg Eye Center, and Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48105, USA.
| | - David A Antonetti
- Departments of Ophthalmology and Visual Sciences, Kellogg Eye Center, and Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48105, USA.
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35
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Rueda EM, Johnson JE, Giddabasappa A, Swaroop A, Brooks MJ, Sigel I, Chaney SY, Fox DA. The cellular and compartmental profile of mouse retinal glycolysis, tricarboxylic acid cycle, oxidative phosphorylation, and ~P transferring kinases. Mol Vis 2016; 22:847-85. [PMID: 27499608 PMCID: PMC4961465] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2016] [Accepted: 07/21/2016] [Indexed: 10/26/2022] Open
Abstract
PURPOSE The homeostatic regulation of cellular ATP is achieved by the coordinated activity of ATP utilization, synthesis, and buffering. Glucose is the major substrate for ATP synthesis through glycolysis and oxidative phosphorylation (OXPHOS), whereas intermediary metabolism through the tricarboxylic acid (TCA) cycle utilizes non-glucose-derived monocarboxylates, amino acids, and alpha ketoacids to support mitochondrial ATP and GTP synthesis. Cellular ATP is buffered by specialized equilibrium-driven high-energy phosphate (~P) transferring kinases. Our goals were twofold: 1) to characterize the gene expression, protein expression, and activity of key synthesizing and regulating enzymes of energy metabolism in the whole mouse retina, retinal compartments, and/or cells and 2) to provide an integrative analysis of the results related to function. METHODS mRNA expression data of energy-related genes were extracted from our whole retinal Affymetrix microarray data. Fixed-frozen retinas from adult C57BL/6N mice were used for immunohistochemistry, laser scanning confocal microscopy, and enzymatic histochemistry. The immunoreactivity levels of well-characterized antibodies, for all major retinal cells and their compartments, were obtained using our established semiquantitative confocal and imaging techniques. Quantitative cytochrome oxidase (COX) and lactate dehydrogenase (LDH) activity was determined histochemically. RESULTS The Affymetrix data revealed varied gene expression patterns of the ATP synthesizing and regulating enzymes found in the muscle, liver, and brain. Confocal studies showed differential cellular and compartmental distribution of isozymes involved in glucose, glutamate, glutamine, lactate, and creatine metabolism. The pattern and intensity of the antibodies and of the COX and LDH activity showed the high capacity of photoreceptors for aerobic glycolysis and OXPHOS. Competition assays with pyruvate revealed that LDH-5 was localized in the photoreceptor inner segments. The combined results indicate that glycolysis is regulated by the compartmental expression of hexokinase 2, pyruvate kinase M1, and pyruvate kinase M2 in photoreceptors, whereas the inner retinal neurons exhibit a lower capacity for glycolysis and aerobic glycolysis. Expression of nucleoside diphosphate kinase, mitochondria-associated adenylate kinase, and several mitochondria-associated creatine kinase isozymes was highest in the outer retina, whereas expression of cytosolic adenylate kinase and brain creatine kinase was higher in the cones, horizontal cells, and amacrine cells indicating the diversity of ATP-buffering strategies among retinal neurons. Based on the antibody intensities and the COX and LDH activity, Müller glial cells (MGCs) had the lowest capacity for glycolysis, aerobic glycolysis, and OXPHOS. However, they showed high expression of glutamate dehydrogenase, alpha-ketoglutarate dehydrogenase, succinate thiokinase, GABA transaminase, and ~P transferring kinases. This suggests that MGCs utilize TCA cycle anaplerosis and cataplerosis to generate GTP and ~P transferring kinases to produce ATP that supports MGC energy requirements. CONCLUSIONS Our comprehensive and integrated results reveal that the adult mouse retina expresses numerous isoforms of ATP synthesizing, regulating, and buffering genes; expresses differential cellular and compartmental levels of glycolytic, OXPHOS, TCA cycle, and ~P transferring kinase proteins; and exhibits differential layer-by-layer LDH and COX activity. New insights into cell-specific and compartmental ATP and GTP production, as well as utilization and buffering strategies and their relationship with known retinal and cellular functions, are discussed. Developing therapeutic strategies for neuroprotection and treating retinal deficits and degeneration in a cell-specific manner will require such knowledge. This work provides a platform for future research directed at identifying the molecular targets and proteins that regulate these processes.
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Affiliation(s)
- Elda M. Rueda
- College of Optometry, University of Houston, Houston TX
| | - Jerry E. Johnson
- Department of Natural Sciences, University of Houston-Downtown, Houston TX
- Department of Biology and Biochemistry, University of Houston, Houston TX
| | - Anand Giddabasappa
- Department of Biology and Biochemistry, University of Houston, Houston TX
| | | | | | - Irena Sigel
- College of Optometry, University of Houston, Houston TX
| | - Shawnta Y. Chaney
- Department of Biology and Biochemistry, University of Houston, Houston TX
| | - Donald A. Fox
- College of Optometry, University of Houston, Houston TX
- Department of Biology and Biochemistry, University of Houston, Houston TX
- Department of Pharmacology and Pharmaceutical Sciences, University of Houston, Houston TX
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Nagana Gowda GA, Abell L, Lee CF, Tian R, Raftery D. Simultaneous Analysis of Major Coenzymes of Cellular Redox Reactions and Energy Using ex Vivo (1)H NMR Spectroscopy. Anal Chem 2016; 88:4817-24. [PMID: 27043450 PMCID: PMC4857157 DOI: 10.1021/acs.analchem.6b00442] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Accepted: 04/04/2016] [Indexed: 01/08/2023]
Abstract
Coenzymes of cellular redox reactions and cellular energy mediate biochemical reactions fundamental to the functioning of all living cells. Despite their immense interest, no simple method exists to gain insights into their cellular concentrations in a single step. We show that a simple (1)H NMR experiment can simultaneously measure oxidized and reduced forms of nicotinamide adenine dinucleotide (NAD(+) and NADH), oxidized and reduced forms of nicotinamide adenine dinucleotide phosphate (NADP(+) and NADPH), and adenosine triphosphate (ATP) and its precursors, adenosine diphosphate (ADP) and adenosine monophosphate (AMP), using mouse heart, kidney, brain, liver, and skeletal muscle tissue extracts as examples. Combining 1D/2D NMR experiments, chemical shift libraries, and authentic compound data, reliable peak identities for these coenzymes have been established. To assess this methodology, cardiac NADH and NAD(+) ratios/pool sizes were measured using mouse models with a cardiac-specific knockout of the mitochondrial Complex I Ndufs4 gene (cKO) and cardiac-specific overexpression of nicotinamide phosphoribosyltransferase (cNAMPT) as examples. Sensitivity of NAD(+) and NADH to cKO or cNAMPT was observed, as anticipated. Time-dependent investigations showed that the levels of NADH and NADPH diminish by up to ∼50% within 24 h; concomitantly, NAD(+) and NADP(+) increase proportionately; however, degassing the sample and flushing the sample tubes with helium gas halted such changes. The analysis protocol along with the annotated characteristic fingerprints for each coenzyme is provided for easy identification and absolute quantification using a single internal reference for routine use. The ability to visualize the ubiquitous coenzymes fundamental to cellular functions, simultaneously and reliably, offers a new avenue to interrogate the mechanistic details of cellular function in health and disease.
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Affiliation(s)
- G. A. Nagana Gowda
- Northwest Metabolomics Research Center, Mitochondria and Metabolism Center,
Anesthesiology and Pain Medicine, and Department of Chemistry, University of Washington, Seattle, Washington 98109, United States
| | - Lauren Abell
- Northwest Metabolomics Research Center, Mitochondria and Metabolism Center,
Anesthesiology and Pain Medicine, and Department of Chemistry, University of Washington, Seattle, Washington 98109, United States
| | - Chi Fung Lee
- Northwest Metabolomics Research Center, Mitochondria and Metabolism Center,
Anesthesiology and Pain Medicine, and Department of Chemistry, University of Washington, Seattle, Washington 98109, United States
| | - Rong Tian
- Northwest Metabolomics Research Center, Mitochondria and Metabolism Center,
Anesthesiology and Pain Medicine, and Department of Chemistry, University of Washington, Seattle, Washington 98109, United States
| | - Daniel Raftery
- Northwest Metabolomics Research Center, Mitochondria and Metabolism Center,
Anesthesiology and Pain Medicine, and Department of Chemistry, University of Washington, Seattle, Washington 98109, United States
- Fred
Hutchinson Cancer Research Center, Seattle, Washington 98109, United States
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Del Arco A, Contreras L, Pardo B, Satrustegui J. Calcium regulation of mitochondrial carriers. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2016; 1863:2413-21. [PMID: 27033520 DOI: 10.1016/j.bbamcr.2016.03.024] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Revised: 03/23/2016] [Accepted: 03/23/2016] [Indexed: 11/16/2022]
Abstract
Mitochondrial function is regulated by calcium. In addition to the long known effects of matrix Ca(2+), regulation of metabolite transport by extramitochondrial Ca(2+) represents an alternative Ca(2+)-dependent mechanism to regulate mitochondrial function. The Ca(2+) regulated mitochondrial transporters (CaMCs) are well suited for that role, as they contain long N-terminal extensions harboring EF-hand Ca(2+) binding domains facing the intermembrane space. They fall in two groups, the aspartate/glutamate exchangers, AGCs, major components of the NADH malate aspartate shuttle (MAS) and urea cycle, and the ATP-Mg(2+)/Pi exchangers or short CaMCs (APCs or SCaMCs). The AGCs are activated by relatively low Ca(2+) levels only slightly higher than resting Ca(2+), whereas all SCaMCs studied so far require strong Ca(2+) signals, above micromolar, for activation. In addition, AGCs are not strictly Ca(2+) dependent, being active even in Ca(2+)-free conditions. Thus, AGCs are well suited to respond to small Ca(2+) signals and that do not reach mitochondria. In contrast, ATP-Mg(2+)/Pi carriers are inactive in Ca(2+) free conditions and activation requires Ca(2+) signals that will also activate the calcium uniporter (MCU). By changing the net content of adenine nucleotides of the matrix upon activation, SCaMCs regulate the activity of the permeability transition pore, and the Ca(2+) retention capacity of mitochondria (CRC), two functions synergizing with those of the MCU. The different Ca(2+) activation properties of the two CaMCs are discussed in relation to their newly obtained structures. This article is part of a Special Issue entitled: Mitochondrial Channels edited by Pierre Sonveaux, Pierre Maechler and Jean-Claude Martinou.
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Affiliation(s)
- Araceli Del Arco
- Facultad de Ciencias Ambientales y Bioquímica, Centro RegionaI de Investigaciones Biomédicas, Universidad de Castilla la Mancha, Toledo 45071, Spain; CIBER de Enfermedades Raras (CIBERER), ISCIII, Madrid, Spain; Instituto de Investigaciones Sanitarias Fundación Jiménez Díaz (IIS-FJD), Madrid, Spain
| | - Laura Contreras
- Departamento de Biología Molecular, Centro de Biología Molecular Severo Ochoa, Universidad Autónoma de Madrid-Consejo Superior de Investigaciones Científicas, 28049 Madrid, Spain; CIBER de Enfermedades Raras (CIBERER), ISCIII, Madrid, Spain; Instituto de Investigaciones Sanitarias Fundación Jiménez Díaz (IIS-FJD), Madrid, Spain
| | - Beatriz Pardo
- Departamento de Biología Molecular, Centro de Biología Molecular Severo Ochoa, Universidad Autónoma de Madrid-Consejo Superior de Investigaciones Científicas, 28049 Madrid, Spain; CIBER de Enfermedades Raras (CIBERER), ISCIII, Madrid, Spain; Instituto de Investigaciones Sanitarias Fundación Jiménez Díaz (IIS-FJD), Madrid, Spain
| | - Jorgina Satrustegui
- Departamento de Biología Molecular, Centro de Biología Molecular Severo Ochoa, Universidad Autónoma de Madrid-Consejo Superior de Investigaciones Científicas, 28049 Madrid, Spain; CIBER de Enfermedades Raras (CIBERER), ISCIII, Madrid, Spain; Instituto de Investigaciones Sanitarias Fundación Jiménez Díaz (IIS-FJD), Madrid, Spain.
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Du J, Rountree A, Cleghorn WM, Contreras L, Lindsay KJ, Sadilek M, Gu H, Djukovic D, Raftery D, Satrústegui J, Kanow M, Chan L, Tsang SH, Sweet IR, Hurley JB. Phototransduction Influences Metabolic Flux and Nucleotide Metabolism in Mouse Retina. J Biol Chem 2015; 291:4698-710. [PMID: 26677218 DOI: 10.1074/jbc.m115.698985] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Indexed: 01/20/2023] Open
Abstract
Production of energy in a cell must keep pace with demand. Photoreceptors use ATP to maintain ion gradients in darkness, whereas in light they use it to support phototransduction. Matching production with consumption can be accomplished by coupling production directly to consumption. Alternatively, production can be set by a signal that anticipates demand. In this report we investigate the hypothesis that signaling through phototransduction controls production of energy in mouse retinas. We found that respiration in mouse retinas is not coupled tightly to ATP consumption. By analyzing metabolic flux in mouse retinas, we also found that phototransduction slows metabolic flux through glycolysis and through intermediates of the citric acid cycle. We also evaluated the relative contributions of regulation of the activities of α-ketoglutarate dehydrogenase and the aspartate-glutamate carrier 1. In addition, a comprehensive analysis of the retinal metabolome showed that phototransduction also influences steady-state concentrations of 5'-GMP, ribose-5-phosphate, ketone bodies, and purines.
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Affiliation(s)
- Jianhai Du
- From the Department of Biochemistry, Department of Ophthalmology, University of Washington, Seattle, Washington 98109
| | | | | | - Laura Contreras
- Department of Molecular Biology, Centre for Molecular Biology Severo Ochoa, Universidad Autonoma de Madrid-Consejo Superior de Investigaciones Científicas, CIBER of Rare Diseases (CIBERER), and Health Research Institute Jimenez Diaz Foundation, Autonomous University of Madrid, 28049 Madrid, Spain
| | | | | | - Haiwei Gu
- Northwest Metabolomics Research Center, Department of Anesthesiology and Pain Medicine
| | - Danijel Djukovic
- Northwest Metabolomics Research Center, Department of Anesthesiology and Pain Medicine
| | - Dan Raftery
- Northwest Metabolomics Research Center, Department of Anesthesiology and Pain Medicine
| | - Jorgina Satrústegui
- Department of Molecular Biology, Centre for Molecular Biology Severo Ochoa, Universidad Autonoma de Madrid-Consejo Superior de Investigaciones Científicas, CIBER of Rare Diseases (CIBERER), and Health Research Institute Jimenez Diaz Foundation, Autonomous University of Madrid, 28049 Madrid, Spain
| | | | - Lawrence Chan
- Bernard and Shirlee Brown Glaucoma Laboratory and Barbara and Donald Jonas Stem Cell Laboratory, Department of Ophthalmology, Columbia University, New York, New York, and
| | - Stephen H Tsang
- Bernard and Shirlee Brown Glaucoma Laboratory and Barbara and Donald Jonas Stem Cell Laboratory, Department of Ophthalmology, Columbia University, New York, New York, and Department of Pathology and Cell Biology and Institute of Human Nutrition, Columbia University, New York, New York 10032
| | | | - James B Hurley
- From the Department of Biochemistry, Department of Ophthalmology, University of Washington, Seattle, Washington 98109,
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39
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Contreras L. Role of AGC1/aralar in the metabolic synergies between neuron and glia. Neurochem Int 2015; 88:38-46. [DOI: 10.1016/j.neuint.2015.04.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Revised: 03/30/2015] [Accepted: 04/07/2015] [Indexed: 10/23/2022]
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Hurley JB, Lindsay KJ, Du J. Glucose, lactate, and shuttling of metabolites in vertebrate retinas. J Neurosci Res 2015; 93:1079-92. [PMID: 25801286 PMCID: PMC4720126 DOI: 10.1002/jnr.23583] [Citation(s) in RCA: 175] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2014] [Revised: 02/11/2015] [Accepted: 02/12/2015] [Indexed: 02/06/2023]
Abstract
The vertebrate retina has specific functions and structures that give it a unique set of constraints on the way in which it can produce and use metabolic energy. The retina's response to illumination influences its energy requirements, and the retina's laminated structure influences the extent to which neurons and glia can access metabolic fuels. There are fundamental differences between energy metabolism in retina and that in brain. The retina relies on aerobic glycolysis much more than the brain does, and morphological differences between retina and brain limit the types of metabolic relationships that are possible between neurons and glia. This Mini-Review summarizes the unique metabolic features of the retina with a focus on the role of lactate shuttling.
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Affiliation(s)
- James B. Hurley
- Departments of Biochemistry and Ophthalmology, University of Washington, Seattle, Washington
| | - Kenneth J. Lindsay
- Departments of Biochemistry and Ophthalmology, University of Washington, Seattle, Washington
| | - Jianhai Du
- Departments of Biochemistry and Ophthalmology, University of Washington, Seattle, Washington
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41
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Du J, Linton JD, Hurley JB. Probing Metabolism in the Intact Retina Using Stable Isotope Tracers. Methods Enzymol 2015; 561:149-70. [PMID: 26358904 DOI: 10.1016/bs.mie.2015.04.002] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Vertebrate retinas have several characteristics that make them particularly interesting from a metabolic perspective. The retinas have a highly laminated structure, high energy demands, and they share several metabolic features with tumors, such as a strong Warburg effect and abundant pyruvate kinase M2 isoform expression. The energy demands of retinas are both qualitatively and quantitatively different in light and darkness and metabolic dysfunction could cause retinal degeneration. Stable isotope-based metabolic analysis with mass spectrometry is a powerful tool to trace the dynamic metabolic reactions and reveal novel metabolic pathways within cells and between cells in retina. Here, we describe methods to quantify retinal metabolism in intact retinas and discuss applications of these methods to the understanding of neuron-glia interaction, light and dark adaptation, and retinal degenerative diseases.
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Affiliation(s)
- Jianhai Du
- Departments of Biochemistry, University of Washington, Seattle, Washington, USA; Department of Ophthalmology, University of Washington, Seattle, Washington, USA
| | - Jonathan D Linton
- Departments of Biochemistry, University of Washington, Seattle, Washington, USA; Department of Ophthalmology, University of Washington, Seattle, Washington, USA
| | - James B Hurley
- Departments of Biochemistry, University of Washington, Seattle, Washington, USA; Department of Ophthalmology, University of Washington, Seattle, Washington, USA.
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Adijanto J, Du J, Moffat C, Seifert EL, Hurle JB, Philp NJ. The retinal pigment epithelium utilizes fatty acids for ketogenesis. J Biol Chem 2015; 289:20570-82. [PMID: 24898254 DOI: 10.1074/jbc.m114.565457] [Citation(s) in RCA: 119] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Every day, shortly after light onset, photoreceptor cells shed approximately a tenth of their outer segment. The adjacent retinal pigment epithelial (RPE) cells phagocytize and digest shed photoreceptor outer segment, which provides a rich source of fatty acids that could be utilized as an energy substrate. From a microarray analysis, we found that RPE cells express particularly high levels of the mitochondrial HMG-CoA synthase 2 (Hmgcs2) compared with all other tissues (except the liver and colon), leading to the hypothesis that RPE cells, like hepatocytes, can produce β-hydroxybutyrate (β-HB) from fatty acids. Using primary human fetal RPE (hfRPE) cells cultured on Transwell filters with separate apical and basal chambers, we demonstrate that hfRPE cells can metabolize palmitate, a saturated fatty acid that constitutes .15% of all lipids in the photoreceptor outer segment, to produce β-HB. Importantly, we found that hfRPE cells preferentially release β-HB into the apical chamber and that this process is mediated primarily by monocarboxylate transporter isoform 1 (MCT1). Using a GC-MS analysis of (13)C-labeled metabolites, we showed that retinal cells can take up and metabolize (13)C-labeled β-HB into various TCA cycle intermediates and amino acids. Collectively, our data support a novel mechanism of RPE-retina metabolic coupling in which RPE cells metabolize fatty acids to produce β-HB, which is transported to the retina for use as a metabolic substrate.
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Carroll PA, Diolaiti D, McFerrin L, Gu H, Djukovic D, Du J, Cheng PF, Anderson S, Ulrich M, Hurley JB, Raftery D, Ayer DE, Eisenman RN. Deregulated Myc requires MondoA/Mlx for metabolic reprogramming and tumorigenesis. Cancer Cell 2015; 27:271-85. [PMID: 25640402 PMCID: PMC4326605 DOI: 10.1016/j.ccell.2014.11.024] [Citation(s) in RCA: 157] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Revised: 09/02/2014] [Accepted: 11/21/2014] [Indexed: 12/16/2022]
Abstract
Deregulated Myc transcriptionally reprograms cell metabolism to promote neoplasia. Here we show that oncogenic Myc requires the Myc superfamily member MondoA, a nutrient-sensing transcription factor, for tumorigenesis. Knockdown of MondoA, or its dimerization partner Mlx, blocks Myc-induced reprogramming of multiple metabolic pathways, resulting in apoptosis. Identification and knockdown of genes coregulated by Myc and MondoA have allowed us to define metabolic functions required by deregulated Myc and demonstrate a critical role for lipid biosynthesis in survival of Myc-driven cancer. Furthermore, overexpression of a subset of Myc and MondoA coregulated genes correlates with poor outcome of patients with diverse cancers. Coregulation of cancer metabolism by Myc and MondoA provides the potential for therapeutics aimed at inhibiting MondoA and its target genes.
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Affiliation(s)
- Patrick A Carroll
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, MS A2-025, P.O. Box 19024, Seattle, WA 98109-1024, USA
| | - Daniel Diolaiti
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, MS A2-025, P.O. Box 19024, Seattle, WA 98109-1024, USA
| | - Lisa McFerrin
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, MS A2-025, P.O. Box 19024, Seattle, WA 98109-1024, USA
| | - Haiwei Gu
- Northwest Metabolomics Research Center, Department of Anesthesiology and Pain Medicine, University of Washington, 850 Republican Street, Room S148, P.O. Box 358057, Seattle, WA 98109-8057, USA
| | - Danijel Djukovic
- Northwest Metabolomics Research Center, Department of Anesthesiology and Pain Medicine, University of Washington, 850 Republican Street, Room S148, P.O. Box 358057, Seattle, WA 98109-8057, USA
| | - Jianhai Du
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
| | - Pei Feng Cheng
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, MS A2-025, P.O. Box 19024, Seattle, WA 98109-1024, USA
| | - Sarah Anderson
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, MS A2-025, P.O. Box 19024, Seattle, WA 98109-1024, USA
| | - Michelle Ulrich
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, MS A2-025, P.O. Box 19024, Seattle, WA 98109-1024, USA
| | - James B Hurley
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA; Department of Ophthalmology, University of Washington, Seattle, WA 98195, USA
| | - Daniel Raftery
- Northwest Metabolomics Research Center, Department of Anesthesiology and Pain Medicine, University of Washington, 850 Republican Street, Room S148, P.O. Box 358057, Seattle, WA 98109-8057, USA; Division of Public Health Sciences, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue N, Seattle, WA 98109, USA
| | - Donald E Ayer
- Department of Oncological Sciences, Huntsman Cancer Institute, University of Utah, 2000 Circle of Hope, Salt Lake City, UT 84112, USA
| | - Robert N Eisenman
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, MS A2-025, P.O. Box 19024, Seattle, WA 98109-1024, USA.
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Yang C, Ko B, Hensley CT, Jiang L, Wasti AT, Kim J, Sudderth J, Calvaruso MA, Lumata L, Mitsche M, Rutter J, Merritt ME, DeBerardinis RJ. Glutamine oxidation maintains the TCA cycle and cell survival during impaired mitochondrial pyruvate transport. Mol Cell 2014; 56:414-424. [PMID: 25458842 PMCID: PMC4268166 DOI: 10.1016/j.molcel.2014.09.025] [Citation(s) in RCA: 478] [Impact Index Per Article: 47.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2014] [Revised: 08/14/2014] [Accepted: 09/25/2014] [Indexed: 01/05/2023]
Abstract
Alternative modes of metabolism enable cells to resist metabolic stress. Inhibiting these compensatory pathways may produce synthetic lethality. We previously demonstrated that glucose deprivation stimulated a pathway in which acetyl-CoA was formed from glutamine downstream of glutamate dehydrogenase (GDH). Here we show that import of pyruvate into the mitochondria suppresses GDH and glutamine-dependent acetyl-CoA formation. Inhibiting the mitochondrial pyruvate carrier (MPC) activates GDH and reroutes glutamine metabolism to generate both oxaloacetate and acetyl-CoA, enabling persistent tricarboxylic acid (TCA) cycle function. Pharmacological blockade of GDH elicited largely cytostatic effects in culture, but these effects became cytotoxic when combined with MPC inhibition. Concomitant administration of MPC and GDH inhibitors significantly impaired tumor growth compared to either inhibitor used as a single agent. Together, the data define a mechanism to induce glutaminolysis and uncover a survival pathway engaged during compromised supply of pyruvate to the mitochondria.
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Affiliation(s)
- Chendong Yang
- Children's Medical Center Research Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390-8502, USA
| | - Bookyung Ko
- Children's Medical Center Research Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390-8502, USA
| | - Christopher T Hensley
- Children's Medical Center Research Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390-8502, USA
| | - Lei Jiang
- Children's Medical Center Research Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390-8502, USA
| | - Ajla T Wasti
- Children's Medical Center Research Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390-8502, USA; Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX 75390-8502, USA
| | - Jiyeon Kim
- Children's Medical Center Research Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390-8502, USA
| | - Jessica Sudderth
- Children's Medical Center Research Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390-8502, USA
| | - Maria Antonietta Calvaruso
- Children's Medical Center Research Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390-8502, USA
| | - Lloyd Lumata
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX 75390-8502, USA
| | - Matthew Mitsche
- McDermott Center for Human Growth and Development, University of Texas Southwestern Medical Center, Dallas, TX 75390-8502, USA
| | - Jared Rutter
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT 84112-5650, USA
| | - Matthew E Merritt
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX 75390-8502, USA
| | - Ralph J DeBerardinis
- Children's Medical Center Research Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390-8502, USA; Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX 75390-8502, USA; McDermott Center for Human Growth and Development, University of Texas Southwestern Medical Center, Dallas, TX 75390-8502, USA.
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Pyruvate kinase and aspartate-glutamate carrier distributions reveal key metabolic links between neurons and glia in retina. Proc Natl Acad Sci U S A 2014; 111:15579-84. [PMID: 25313047 DOI: 10.1073/pnas.1412441111] [Citation(s) in RCA: 97] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Symbiotic relationships between neurons and glia must adapt to structures, functions, and metabolic roles of the tissues they are in. We show here that Müller glia in retinas have specific enzyme deficiencies that can enhance their ability to synthesize Gln. The metabolic cost of these deficiencies is that they impair the Müller cell's ability to metabolize Glc. We show here that the cells can compensate for this deficiency by using metabolites produced by neurons. Müller glia are deficient for pyruvate kinase (PK) and for aspartate/glutamate carrier 1 (AGC1), a key component of the malate-aspartate shuttle. In contrast, photoreceptor neurons express AGC1 and the M2 isoform of pyruvate kinase, which is commonly associated with aerobic glycolysis in tumors, proliferating cells, and some other cell types. Our findings reveal a previously unidentified type of metabolic relationship between neurons and glia. Müller glia compensate for their unique metabolic adaptations by using lactate and aspartate from neurons as surrogates for their missing PK and AGC1.
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Pardo B, Contreras L, Satrústegui J. De novo Synthesis of Glial Glutamate and Glutamine in Young Mice Requires Aspartate Provided by the Neuronal Mitochondrial Aspartate-Glutamate Carrier Aralar/AGC1. Front Endocrinol (Lausanne) 2013; 4:149. [PMID: 24133485 PMCID: PMC3796713 DOI: 10.3389/fendo.2013.00149] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Accepted: 10/02/2013] [Indexed: 01/14/2023] Open
Affiliation(s)
- Beatriz Pardo
- Departamento de Biología Molecular, Centro de Biología Molecular Severo Ochoa UAM-CSIC, CIBER de Enfermedades Raras (CIBERER), Universidad Autónoma de Madrid, Madrid, Spain
- *Correspondence:
| | - Laura Contreras
- Departamento de Biología Molecular, Centro de Biología Molecular Severo Ochoa UAM-CSIC, CIBER de Enfermedades Raras (CIBERER), Universidad Autónoma de Madrid, Madrid, Spain
| | - Jorgina Satrústegui
- Departamento de Biología Molecular, Centro de Biología Molecular Severo Ochoa UAM-CSIC, CIBER de Enfermedades Raras (CIBERER), Universidad Autónoma de Madrid, Madrid, Spain
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