1
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Lindsay RT, Thisted L, Zois NE, Thrane ST, West JA, Fosgerau K, Griffin JL, Fink LN, Murray AJ. Beta-adrenergic agonism protects mitochondrial metabolism in the pancreatectomised rat heart. Sci Rep 2024; 14:19383. [PMID: 39169098 PMCID: PMC11339431 DOI: 10.1038/s41598-024-70335-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2024] [Accepted: 08/14/2024] [Indexed: 08/23/2024] Open
Abstract
The diabetic heart is characterised by functional, morphological and metabolic alterations predisposing it to contractile failure. Chronic sympathetic activation is a feature of the pathogenesis of heart failure, however the type 1 diabetic heart shows desensitisation to β-adrenergic stimulation. Here, we sought to understand the impact of repeated isoprenaline-mediated β-stimulation upon cardiac mitochondrial respiratory capacity and substrate metabolism in the 90% pancreatectomy (Px) rat model of type 1 diabetes. We hypothesised these hearts would be relatively protected against the metabolic impact of stress-induced cardiomyopathy. We found that individually both Px and isoprenaline suppressed cardiac mitochondrial respiration, but that this was preserved in Px rats receiving isoprenaline. Px and isoprenaline had contrasting effects on cardiac substrate metabolism, with increased reliance upon cardiac fatty acid oxidation capacity and altered ketone metabolism in the hearts of Px rats, but enhanced capacity for glucose uptake and metabolism in isoprenaline-treated rats. Moreover, Px rats were protected against isoprenaline-induced mortality, whilst isoprenaline elevated cGMP and protected myocardial energetic status in Px rat hearts. Our work suggests that adrenergic stimulation may be protective in the type 1 diabetic heart, and underlines the importance of studying pathological features in combination when modeling complex disease in rodents.
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Affiliation(s)
- Ross T Lindsay
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK.
- Gubra A/S, Hørsholm Kongevej 11B, 2970, Hørsholm, Denmark.
- Department of Biochemistry and Systems Biology Centre, University of Cambridge, Cambridge, UK.
| | - Louise Thisted
- Gubra A/S, Hørsholm Kongevej 11B, 2970, Hørsholm, Denmark
| | - Nora E Zois
- Gubra A/S, Hørsholm Kongevej 11B, 2970, Hørsholm, Denmark
- Ascendis Pharma A/S, Hellerup, Denmark
| | | | - James A West
- Department of Biochemistry and Systems Biology Centre, University of Cambridge, Cambridge, UK
- AstraZeneca, Cambridge, UK
| | - Keld Fosgerau
- Gubra A/S, Hørsholm Kongevej 11B, 2970, Hørsholm, Denmark
- Pephexia Therapeutics ApS, Copenhagen, Denmark
| | - Julian L Griffin
- Department of Biochemistry and Systems Biology Centre, University of Cambridge, Cambridge, UK
- The Rowett Institute, University of Aberdeen, Aberdeen, UK
| | - Lisbeth N Fink
- Gubra A/S, Hørsholm Kongevej 11B, 2970, Hørsholm, Denmark
- Ferring Pharmaceuticals A/S, Kastrup, Denmark
| | - Andrew J Murray
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK
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2
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O'Brien KA, McNally BD, Sowton AP, Murgia A, Armitage J, Thomas LW, Krause FN, Maddalena LA, Francis I, Kavanagh S, Williams DP, Ashcroft M, Griffin JL, Lyon JJ, Murray AJ. Enhanced hepatic respiratory capacity and altered lipid metabolism support metabolic homeostasis during short-term hypoxic stress. BMC Biol 2021; 19:265. [PMID: 34911556 PMCID: PMC8675474 DOI: 10.1186/s12915-021-01192-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Accepted: 11/12/2021] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND Tissue hypoxia is a key feature of several endemic hepatic diseases, including alcoholic and non-alcoholic fatty liver disease, and organ failure. Hypoxia imposes a severe metabolic challenge on the liver, potentially disrupting its capacity to carry out essential functions including fuel storage and the integration of lipid metabolism at the whole-body level. Mitochondrial respiratory function is understood to be critical in mediating the hepatic hypoxic response, yet the time-dependent nature of this response and the role of the respiratory chain in this remain unclear. RESULTS Here, we report that hepatic respiratory capacity is enhanced following short-term exposure to hypoxia (2 days, 10% O2) and is associated with increased abundance of the respiratory chain supercomplex III2+IV and increased cardiolipin levels. Suppression of this enhanced respiratory capacity, achieved via mild inhibition of mitochondrial complex III, disrupted metabolic homeostasis. Hypoxic exposure for 2 days led to accumulation of plasma and hepatic long chain acyl-carnitines. This was observed alongside depletion of hepatic triacylglycerol species with total chain lengths of 39-53 carbons, containing palmitic, palmitoleic, stearic, and oleic acids, which are associated with de novo lipogenesis. The changes to hepatic respiratory capacity and lipid metabolism following 2 days hypoxic exposure were transient, becoming resolved after 14 days in line with systemic acclimation to hypoxia and elevated circulating haemoglobin concentrations. CONCLUSIONS The liver maintains metabolic homeostasis in response to shorter term hypoxic exposure through transient enhancement of respiratory chain capacity and alterations to lipid metabolism. These findings may have implications in understanding and treating hepatic pathologies associated with hypoxia.
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Affiliation(s)
- Katie A O'Brien
- Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge, CB2 3EG, UK.
| | - Ben D McNally
- Department of Biochemistry and Cambridge Systems Biology Centre, University of Cambridge, Sanger Building Tennis Court Road, Cambridge, CB2 1GA, UK
| | - Alice P Sowton
- Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge, CB2 3EG, UK
| | - Antonio Murgia
- Department of Biochemistry and Cambridge Systems Biology Centre, University of Cambridge, Sanger Building Tennis Court Road, Cambridge, CB2 1GA, UK
| | - James Armitage
- Global Investigative Safety, GlaxoSmithKline R&D, Park Road, Ware, Hertfordshire, SG12 0DP, UK
| | - Luke W Thomas
- Department of Medicine, University of Cambridge, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0QQ, UK
| | - Fynn N Krause
- Department of Biochemistry and Cambridge Systems Biology Centre, University of Cambridge, Sanger Building Tennis Court Road, Cambridge, CB2 1GA, UK
| | - Lucas A Maddalena
- Department of Medicine, University of Cambridge, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0QQ, UK
| | - Ian Francis
- Ultrastructure and Cellular Bioimaging, GlaxoSmithKline R&D, Park Road, Ware, Hertfordshire, SG12 0DP, UK
| | - Stefan Kavanagh
- Oncology Safety Sciences, Clinical Pharmacology & Safety Sciences, R&D, AstraZeneca, CB2 OAA, Cambridge, UK
| | - Dominic P Williams
- Functional and Mechanistic Safety, Clinical Pharmacology & Safety Sciences, R&D, AstraZeneca, CB2 OAA, Cambridge, UK
| | - Margaret Ashcroft
- Department of Medicine, University of Cambridge, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0QQ, UK
| | - Julian L Griffin
- Department of Biochemistry and Cambridge Systems Biology Centre, University of Cambridge, Sanger Building Tennis Court Road, Cambridge, CB2 1GA, UK
- Section of Biomolecular Medicine, Department of Digestion, Metabolism and Reproduction, Imperial College London, South Kensington Campus, London, SW7 2AZ, UK
| | - Jonathan J Lyon
- Global Investigative Safety, GlaxoSmithKline R&D, Park Road, Ware, Hertfordshire, SG12 0DP, UK
| | - Andrew J Murray
- Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge, CB2 3EG, UK.
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3
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Parker AM, Tate M, Prakoso D, Deo M, Willis AM, Nash DM, Donner DG, Crawford S, Kiriazis H, Granata C, Coughlan MT, De Blasio MJ, Ritchie RH. Characterisation of the Myocardial Mitochondria Structural and Functional Phenotype in a Murine Model of Diabetic Cardiomyopathy. Front Physiol 2021; 12:672252. [PMID: 34539423 PMCID: PMC8442993 DOI: 10.3389/fphys.2021.672252] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Accepted: 08/10/2021] [Indexed: 12/26/2022] Open
Abstract
People affected by diabetes are at an increased risk of developing heart failure than their non-diabetic counterparts, attributed in part to a distinct cardiac pathology termed diabetic cardiomyopathy. Mitochondrial dysfunction and excess reactive oxygen species (ROS) have been implicated in a range of diabetic complications and are a common feature of the diabetic heart. In this study, we sought to characterise impairments in mitochondrial structure and function in a recently described experimental mouse model of diabetic cardiomyopathy. Diabetes was induced in 6-week-old male FVB/N mice by the combination of three consecutive-daily injections of low-dose streptozotocin (STZ, each 55 mg/kg i.p.) and high-fat diet (42% fat from lipids) for 26 weeks. At study end, diabetic mice exhibited elevated blood glucose levels and impaired glucose tolerance, together with increases in both body weight gain and fat mass, replicating several aspects of human type 2 diabetes. The myocardial phenotype of diabetic mice included increased myocardial fibrosis and left ventricular (LV) diastolic dysfunction. Elevated LV superoxide levels were also evident. Diabetic mice exhibited a spectrum of LV mitochondrial changes, including decreased mitochondria area, increased levels of mitochondrial complex-III and complex-V protein abundance, and reduced complex-II oxygen consumption. In conclusion, these data suggest that the low-dose STZ-high fat experimental model replicates some of the mitochondrial changes seen in diabetes, and as such, this model may be useful to study treatments that target the mitochondria in diabetes.
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Affiliation(s)
- Alex M Parker
- Heart Failure Pharmacology, Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, VIC, Australia.,Baker Heart & Diabetes Institute, Melbourne, VIC, Australia.,Department of Pharmacology and Therapeutics, The University of Melbourne, Melbourne, VIC, Australia
| | - Mitchel Tate
- Heart Failure Pharmacology, Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, VIC, Australia.,Baker Heart & Diabetes Institute, Melbourne, VIC, Australia
| | - Darnel Prakoso
- Heart Failure Pharmacology, Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, VIC, Australia.,Baker Heart & Diabetes Institute, Melbourne, VIC, Australia
| | - Minh Deo
- Heart Failure Pharmacology, Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, VIC, Australia
| | - Andrew M Willis
- Heart Failure Pharmacology, Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, VIC, Australia
| | - David M Nash
- Heart Failure Pharmacology, Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, VIC, Australia
| | - Daniel G Donner
- Baker Heart & Diabetes Institute, Melbourne, VIC, Australia.,Baker Department of Cardiometabolic Health, The University of Melbourne, Melbourne, VIC, Australia
| | - Simon Crawford
- Ramaciotti Centre for Cryo-Electron Microscopy, Monash University, Melbourne, VIC, Australia
| | - Helen Kiriazis
- Baker Heart & Diabetes Institute, Melbourne, VIC, Australia.,Baker Department of Cardiometabolic Health, The University of Melbourne, Melbourne, VIC, Australia
| | - Cesare Granata
- Department of Diabetes, Monash University, Melbourne, VIC, Australia.,Institute for Health and Sport, Victoria University, Melbourne, VIC, Australia
| | | | - Miles J De Blasio
- Heart Failure Pharmacology, Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, VIC, Australia.,Baker Heart & Diabetes Institute, Melbourne, VIC, Australia.,Department of Pharmacology, Monash University, Melbourne, VIC, Australia
| | - Rebecca H Ritchie
- Heart Failure Pharmacology, Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, VIC, Australia.,Baker Heart & Diabetes Institute, Melbourne, VIC, Australia.,Department of Pharmacology and Therapeutics, The University of Melbourne, Melbourne, VIC, Australia.,Department of Pharmacology, Monash University, Melbourne, VIC, Australia
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4
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Lindsay RT, Dieckmann S, Krzyzanska D, Manetta-Jones D, West JA, Castro C, Griffin JL, Murray AJ. β-hydroxybutyrate accumulates in the rat heart during low-flow ischaemia with implications for functional recovery. eLife 2021; 10:e71270. [PMID: 34491199 PMCID: PMC8423437 DOI: 10.7554/elife.71270] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Accepted: 08/23/2021] [Indexed: 12/15/2022] Open
Abstract
Extrahepatic tissues which oxidise ketone bodies also have the capacity to accumulate them under particular conditions. We hypothesised that acetyl-coenzyme A (acetyl-CoA) accumulation and altered redox status during low-flow ischaemia would support ketone body production in the heart. Combining a Langendorff heart model of low-flow ischaemia/reperfusion with liquid chromatography coupled tandem mass spectrometry (LC-MS/MS), we show that β-hydroxybutyrate (β-OHB) accumulated in the ischaemic heart to 23.9 nmol/gww and was secreted into the coronary effluent. Sodium oxamate, a lactate dehydrogenase (LDH) inhibitor, increased ischaemic β-OHB levels 5.3-fold and slowed contractile recovery. Inhibition of β-hydroxy-β-methylglutaryl (HMG)-CoA synthase (HMGCS2) with hymeglusin lowered ischaemic β-OHB accumulation by 40%, despite increased flux through succinyl-CoA-3-oxaloacid CoA transferase (SCOT), resulting in greater contractile recovery. Hymeglusin also protected cardiac mitochondrial respiratory capacity during ischaemia/reperfusion. In conclusion, net ketone generation occurs in the heart under conditions of low-flow ischaemia. The process is driven by flux through both HMGCS2 and SCOT, and impacts on cardiac functional recovery from ischaemia/reperfusion.
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Affiliation(s)
- Ross T Lindsay
- Department of Physiology, Development and Neuroscience, University of CambridgeLondonUnited Kingdom
- Department of Biochemistry and Cambridge Systems Biology Centre, University of CambridgeLondonUnited Kingdom
| | - Sophie Dieckmann
- Department of Physiology, Development and Neuroscience, University of CambridgeLondonUnited Kingdom
| | - Dominika Krzyzanska
- Department of Physiology, Development and Neuroscience, University of CambridgeLondonUnited Kingdom
| | - Dominic Manetta-Jones
- Department of Physiology, Development and Neuroscience, University of CambridgeLondonUnited Kingdom
| | - James A West
- Department of Biochemistry and Cambridge Systems Biology Centre, University of CambridgeLondonUnited Kingdom
| | - Cecilia Castro
- Department of Biochemistry and Cambridge Systems Biology Centre, University of CambridgeLondonUnited Kingdom
| | - Julian L Griffin
- Department of Biochemistry and Cambridge Systems Biology Centre, University of CambridgeLondonUnited Kingdom
- Section of Biomolecular Medicine, Systems Medicine, Department of Metabolism, Digestion and Reproduction, Imperial College LondonLondonUnited Kingdom
| | - Andrew J Murray
- Department of Physiology, Development and Neuroscience, University of CambridgeLondonUnited Kingdom
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5
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Su Z, Liu Y, Zhang H. Adaptive Cardiac Metabolism Under Chronic Hypoxia: Mechanism and Clinical Implications. Front Cell Dev Biol 2021; 9:625524. [PMID: 33604337 PMCID: PMC7884626 DOI: 10.3389/fcell.2021.625524] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Accepted: 01/11/2021] [Indexed: 11/29/2022] Open
Abstract
Chronic hypoxia is an essential component in many cardiac diseases. The heart consumes a substantial amount of energy and it is important to maintain the balance of energy supply and demand when oxygen is limited. Previous studies showed that the heart switches from fatty acid to glucose to maintain metabolic efficiency in the adaptation to chronic hypoxia. However, the underlying mechanism of this adaptive cardiac metabolism remains to be fully characterized. Moreover, how the altered cardiac metabolism affects the heart function in patients with chronic hypoxia has not been discussed in the current literature. In this review, we summarized new findings from animal and human studies to illustrate the mechanism underlying the adaptive cardiac metabolism under chronic hypoxia. Clinical focus is given to certain patients that are subject to the impact of chronic hypoxia, and potential treatment strategies that modulate cardiac metabolism and may improve the heart function in these patients are also summarized.
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Affiliation(s)
- Zhanhao Su
- State Key Laboratory of Cardiovascular Disease, National Center for Cardiovascular Diseases, Fuwai Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Yiwei Liu
- Heart center and Shanghai Institute of Pediatric Congenital Heart Disease, Shanghai Children's Medical Center, National Children's Medical Center, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Hao Zhang
- Heart center and Shanghai Institute of Pediatric Congenital Heart Disease, Shanghai Children's Medical Center, National Children's Medical Center, Shanghai Jiaotong University School of Medicine, Shanghai, China
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6
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Elhassan YS, Kluckova K, Fletcher RS, Schmidt MS, Garten A, Doig CL, Cartwright DM, Oakey L, Burley CV, Jenkinson N, Wilson M, Lucas SJE, Akerman I, Seabright A, Lai YC, Tennant DA, Nightingale P, Wallis GA, Manolopoulos KN, Brenner C, Philp A, Lavery GG. Nicotinamide Riboside Augments the Aged Human Skeletal Muscle NAD + Metabolome and Induces Transcriptomic and Anti-inflammatory Signatures. Cell Rep 2020; 28:1717-1728.e6. [PMID: 31412242 PMCID: PMC6702140 DOI: 10.1016/j.celrep.2019.07.043] [Citation(s) in RCA: 257] [Impact Index Per Article: 64.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Revised: 06/28/2019] [Accepted: 07/15/2019] [Indexed: 11/25/2022] Open
Abstract
Nicotinamide adenine dinucleotide (NAD+) is modulated by conditions of metabolic stress and has been reported to decline with aging in preclinical models, but human data are sparse. Nicotinamide riboside (NR) supplementation ameliorates metabolic dysfunction in rodents. We aimed to establish whether oral NR supplementation in aged participants can increase the skeletal muscle NAD+ metabolome and if it can alter muscle mitochondrial bioenergetics. We supplemented 12 aged men with 1 g NR per day for 21 days in a placebo-controlled, randomized, double-blind, crossover trial. Targeted metabolomics showed that NR elevated the muscle NAD+ metabolome, evident by increased nicotinic acid adenine dinucleotide and nicotinamide clearance products. Muscle RNA sequencing revealed NR-mediated downregulation of energy metabolism and mitochondria pathways, without altering mitochondrial bioenergetics. NR also depressed levels of circulating inflammatory cytokines. Our data establish that oral NR is available to aged human muscle and identify anti-inflammatory effects of NR. NR supplementation in aged subjects augments the skeletal muscle NAD+ metabolome NR supplementation does not affect skeletal muscle mitochondrial bioenergetics NR supplementation reduces levels of circulating inflammatory cytokines
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Affiliation(s)
- Yasir S Elhassan
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, UK; Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham, UK; MRC-Arthritis Research UK Centre for Musculoskeletal Ageing Research, Institute of Inflammation and Ageing, University of Birmingham, Birmingham, UK
| | - Katarina Kluckova
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, UK
| | - Rachel S Fletcher
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, UK
| | - Mark S Schmidt
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Antje Garten
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, UK
| | - Craig L Doig
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, UK
| | - David M Cartwright
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, UK
| | - Lucy Oakey
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, UK
| | - Claire V Burley
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, UK; Centre for Human Brain Health, University of Birmingham, Birmingham, UK
| | - Ned Jenkinson
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, UK; Centre for Human Brain Health, University of Birmingham, Birmingham, UK
| | - Martin Wilson
- Centre for Human Brain Health, University of Birmingham, Birmingham, UK; School of Psychology, University of Birmingham, Birmingham, UK
| | - Samuel J E Lucas
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, UK; Centre for Human Brain Health, University of Birmingham, Birmingham, UK
| | - Ildem Akerman
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, UK
| | - Alex Seabright
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, UK
| | - Yu-Chiang Lai
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, UK
| | - Daniel A Tennant
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, UK
| | - Peter Nightingale
- Institute of Translational Medicine, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK
| | - Gareth A Wallis
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, UK
| | - Konstantinos N Manolopoulos
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, UK; Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham, UK
| | - Charles Brenner
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Andrew Philp
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, UK; Diabetes and Metabolism Division, Garvan Institute of Medical Research, Sydney, NSW, Australia; Faculty of Medicine, St. Vincent's Clinical School, Sydney, UNSW, Australia
| | - Gareth G Lavery
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, UK; Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham, UK; MRC-Arthritis Research UK Centre for Musculoskeletal Ageing Research, Institute of Inflammation and Ageing, University of Birmingham, Birmingham, UK.
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7
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Horscroft JA, O'Brien KA, Clark AD, Lindsay RT, Steel AS, Procter NEK, Devaux J, Frenneaux M, Harridge SDR, Murray AJ. Inorganic nitrate, hypoxia, and the regulation of cardiac mitochondrial respiration-probing the role of PPARα. FASEB J 2019; 33:7563-7577. [PMID: 30870003 PMCID: PMC6529343 DOI: 10.1096/fj.201900067r] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Dietary inorganic nitrate prevents aspects of cardiac mitochondrial dysfunction induced by hypoxia, although the mechanism is not completely understood. In both heart and skeletal muscle, nitrate increases fatty acid oxidation capacity, and in the latter case, this involves up-regulation of peroxisome proliferator-activated receptor (PPAR)α expression. Here, we investigated whether dietary nitrate modifies mitochondrial function in the hypoxic heart in a PPARα-dependent manner. Wild-type (WT) mice and mice without PPARα (Ppara−/−) were given water containing 0.7 mM NaCl (control) or 0.7 mM NaNO3 for 35 d. After 7 d, mice were exposed to normoxia or hypoxia (10% O2) for the remainder of the study. Mitochondrial respiratory function and metabolism were assessed in saponin-permeabilized cardiac muscle fibers. Environmental hypoxia suppressed mass-specific mitochondrial respiration and additionally lowered the proportion of respiration supported by fatty acid oxidation by 18% (P < 0.001). This switch away from fatty acid oxidation was reversed by nitrate treatment in hypoxic WT but not Ppara−/− mice, indicating a PPARα-dependent effect. Hypoxia increased hexokinase activity by 33% in all mice, whereas lactate dehydrogenase activity increased by 71% in hypoxic WT but not Ppara−/− mice. Our findings indicate that PPARα plays a key role in mediating cardiac metabolic remodeling in response to both hypoxia and dietary nitrate supplementation.—Horscroft, J. A., O’Brien, K. A., Clark, A. D., Lindsay, R. T., Steel, A. S., Procter, N. E. K., Devaux, J., Frenneaux, M., Harridge, S. D. R., Murray, A. J. Inorganic nitrate, hypoxia, and the regulation of cardiac mitochondrial respiration—probing the role of PPARα.
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Affiliation(s)
- James A Horscroft
- Department of Physiology, Development, and Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Katie A O'Brien
- Department of Physiology, Development, and Neuroscience, University of Cambridge, Cambridge, United Kingdom.,Centre for Human and Applied Physiological Sciences, King's College London, London, United Kingdom; and
| | - Anna D Clark
- Department of Physiology, Development, and Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Ross T Lindsay
- Department of Physiology, Development, and Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Alice Strang Steel
- Department of Physiology, Development, and Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Nathan E K Procter
- Bob Champion Research and Education Building, University of East Anglia, Norwich, United Kingdom
| | - Jules Devaux
- Department of Physiology, Development, and Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Michael Frenneaux
- Bob Champion Research and Education Building, University of East Anglia, Norwich, United Kingdom
| | - Stephen D R Harridge
- Centre for Human and Applied Physiological Sciences, King's College London, London, United Kingdom; and
| | - Andrew J Murray
- Department of Physiology, Development, and Neuroscience, University of Cambridge, Cambridge, United Kingdom
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8
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O'Brien KA, Horscroft JA, Devaux J, Lindsay RT, Steel AS, Clark AD, Philp A, Harridge SDR, Murray AJ. PPARα-independent effects of nitrate supplementation on skeletal muscle metabolism in hypoxia. Biochim Biophys Acta Mol Basis Dis 2018; 1865:844-853. [PMID: 30055294 PMCID: PMC6414754 DOI: 10.1016/j.bbadis.2018.07.027] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Revised: 07/19/2018] [Accepted: 07/20/2018] [Indexed: 12/20/2022]
Abstract
Hypoxia is a feature of many disease states where convective oxygen delivery is impaired, and is known to suppress oxidative metabolism. Acclimation to hypoxia thus requires metabolic remodelling, however hypoxia tolerance may be aided by dietary nitrate supplementation. Nitrate improves tissue oxygenation and has been shown to modulate skeletal muscle tissue metabolism via transcriptional changes, including through the activation of peroxisome proliferator-activated receptor alpha (PPARα), a master regulator of fat metabolism. Here we investigated whether nitrate supplementation protects skeletal muscle mitochondrial function in hypoxia and whether PPARα is required for this effect. Wild-type and PPARα knockout (PPARα−/−) mice were supplemented with sodium nitrate via the drinking water or sodium chloride as control, and exposed to environmental hypoxia (10% O2) or normoxia for 4 weeks. Hypoxia suppressed mitochondrial respiratory function in mouse soleus, an effect partially alleviated through nitrate supplementation, but occurring independently of PPARα. Specifically, hypoxia resulted in 26% lower mass specific fatty acid-supported LEAK respiration and 23% lower pyruvate-supported oxidative phosphorylation capacity. Hypoxia also resulted in 24% lower citrate synthase activity in mouse soleus, possibly indicating a loss of mitochondrial content. These changes were not seen, however, in hypoxic mice when supplemented with dietary nitrate, indicating a nitrate dependent preservation of mitochondrial function. Moreover, this was observed in both wild-type and PPARα−/− mice. Our results support the notion that nitrate supplementation can aid hypoxia tolerance and indicate that nitrate can exert effects independently of PPARα. Hypoxic exposure suppresses mitochondrial respiration in mouse skeletal muscle. Loss of citrate synthase activity suggests decreased mitochondrial content. Dietary inorganic nitrate partially protects against hypoxia-induced changes. Nitrate protects independently of peroxisome proliferator-activated receptor α.
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Affiliation(s)
- Katie A O'Brien
- Department of Physiology, Development & Neuroscience, University of Cambridge, Cambridge, UK; Centre for Human and Applied Physiological Sciences, King's College London, London, UK.
| | - James A Horscroft
- Department of Physiology, Development & Neuroscience, University of Cambridge, Cambridge, UK
| | - Jules Devaux
- Department of Physiology, Development & Neuroscience, University of Cambridge, Cambridge, UK
| | - Ross T Lindsay
- Department of Physiology, Development & Neuroscience, University of Cambridge, Cambridge, UK
| | - Alice Strang Steel
- Department of Physiology, Development & Neuroscience, University of Cambridge, Cambridge, UK
| | - Anna D Clark
- Department of Physiology, Development & Neuroscience, University of Cambridge, Cambridge, UK
| | - Andrew Philp
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, UK; Diabetes and Metabolism Division, Garvan Institute of Medical Research, Darlinghurst, Australia
| | - Stephen D R Harridge
- Centre for Human and Applied Physiological Sciences, King's College London, London, UK
| | - Andrew J Murray
- Department of Physiology, Development & Neuroscience, University of Cambridge, Cambridge, UK.
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9
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Ferri A, Panariti A, Miserocchi G, Rocchetti M, Buoli Comani G, Rivolta I, Bishop DJ. Tissue specificity of mitochondrial adaptations in rats after 4 weeks of normobaric hypoxia. Eur J Appl Physiol 2018; 118:1641-1652. [PMID: 29855791 DOI: 10.1007/s00421-018-3897-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Accepted: 05/17/2018] [Indexed: 12/23/2022]
Abstract
PURPOSE Exposure to hypoxia has been suggested to activate multiple adaptive pathways so that muscles are better able to maintain cellular energy homeostasis. However, there is limited research regarding the tissue specificity of this response. The aim of this study was to investigate the influence of tissue specificity on mitochondrial adaptations of rat skeletal and heart muscles after 4 weeks of normobaric hypoxia (FiO2: 0.10). METHODS Twenty male Wistar rats were randomly assigned to either normobaric hypoxia or normoxia. Mitochondrial respiration was determined in permeabilised muscle fibres from left and right ventricles, soleus and extensorum digitorum longus (EDL). Citrate synthase activity and the relative abundance of proteins associated with mitochondrial biogenesis were also analysed. RESULTS After hypoxia exposure, only the soleus and left ventricle (both predominantly oxidative) presented a greater maximal mass-specific respiration (+48 and +25%, p < 0.05) and mitochondrial-specific respiration (+75 and +28%, p < 0.05). Citrate synthase activity was higher in the EDL (0.63 ± 0.08 vs 0.41 ± 0.10 µmol min- 1 µg- 1) and lower in the soleus (0.65 ± 0.17 vs 0.87 ± 0.20 µmol min- 1 µg- 1) in hypoxia with respect to normoxia. There was a lower relative protein abundance of PGC-1α (-25%, p < 0.05) in the right ventricle and a higher relative protein abundance of PGC-1β (+43%, p < 0.05) in the left ventricle of rats exposed to hypoxia, with few differences for protein abundance in the other muscles. CONCLUSION Our results show a muscle-specific response to 4 weeks of normobaric hypoxia. Depending on fibre type, and the presence of ventricular hypertrophy, muscles respond differently to the same degree of environmental hypoxia.
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Affiliation(s)
- Alessandra Ferri
- Institute for Health and Sport, Victoria University, Melbourne, Australia.,School of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy
| | - Alice Panariti
- School of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy
| | | | - Marcella Rocchetti
- Department of Biotechnology and Bioscience, University of Milano-Bicocca, Milan, Italy
| | - Gaia Buoli Comani
- School of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy
| | - Ilaria Rivolta
- School of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy.
| | - David J Bishop
- Institute for Health and Sport, Victoria University, Melbourne, Australia. .,School of Medical and Health Sciences, Edith Cowan University, Joondalup, Australia.
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10
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Metabolic adjustment to high-altitude hypoxia: from genetic signals to physiological implications. Biochem Soc Trans 2018; 46:599-607. [PMID: 29678953 DOI: 10.1042/bst20170502] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Revised: 03/24/2018] [Accepted: 03/27/2018] [Indexed: 01/04/2023]
Abstract
Ascent to high altitude is associated with physiological responses that counter the stress of hypobaric hypoxia by increasing oxygen delivery and by altering tissue oxygen utilisation via metabolic modulation. At the cellular level, the transcriptional response to hypoxia is mediated by the hypoxia-inducible factor (HIF) pathway and results in promotion of glycolytic capacity and suppression of oxidative metabolism. In Tibetan highlanders, gene variants encoding components of the HIF pathway have undergone selection and are associated with adaptive phenotypic changes, including suppression of erythropoiesis and increased blood lactate levels. In some highland populations, there has also been a selection of variants in PPARA, encoding peroxisome proliferator-activated receptor alpha (PPARα), a transcriptional regulator of fatty acid metabolism. In one such population, the Sherpas, lower muscle PPARA expression is associated with a decreased capacity for fatty acid oxidation, potentially improving the efficiency of oxygen utilisation. In lowlanders ascending to altitude, a similar suppression of fatty acid oxidation occurs, although the underlying molecular mechanism appears to differ along with the consequences. Unlike lowlanders, Sherpas appear to be protected against oxidative stress and the accumulation of intramuscular lipid intermediates at altitude. Moreover, Sherpas are able to defend muscle ATP and phosphocreatine levels in the face of decreased oxygen delivery, possibly due to suppression of ATP demand pathways. The molecular mechanisms allowing Sherpas to successfully live, work and reproduce at altitude may hold the key to novel therapeutic strategies for the treatment of diseases to which hypoxia is a fundamental contributor.
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Musutova M, Elkalaf M, Klubickova N, Koc M, Povysil S, Rambousek J, Volckaert B, Duska F, Trinh MD, Kalous M, Trnka J, Balusikova K, Kovar J, Polak J. The Effect of Hypoxia and Metformin on Fatty Acid Uptake, Storage, and Oxidation in L6 Differentiated Myotubes. Front Endocrinol (Lausanne) 2018; 9:616. [PMID: 30386299 PMCID: PMC6199370 DOI: 10.3389/fendo.2018.00616] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Accepted: 09/27/2018] [Indexed: 12/25/2022] Open
Abstract
Metabolic impairments associated with obstructive sleep apnea syndrome (OSA) are linked to tissue hypoxia, however, the explanatory molecular and endocrine mechanisms remain unknown. Using gas-permeable cultureware, we studied the chronic effects of mild and severe hypoxia on free fatty acid (FFA) uptake, storage, and oxidation in L6 myotubes under 20, 4, or 1% O2. Additionally, the impact of metformin and the peroxisome proliferator-activated receptor (PPAR) β/δ agonist, called GW501516, were investigated. Exposure to mild and severe hypoxia reduced FFA uptake by 37 and 32%, respectively, while metformin treatment increased FFA uptake by 39% under mild hypoxia. GW501516 reduced FFA uptake under all conditions. Protein expressions of CD36 (cluster of differentiation 36) and SCL27A4 (solute carrier family 27 fatty acid transporter, member 4) were reduced by 17 and 23% under severe hypoxia. Gene expression of UCP2 (uncoupling protein 2) was reduced by severe hypoxia by 81%. Metformin increased CD36 protein levels by 28% under control conditions and SCL27A4 levels by 56% under mild hypoxia. Intracellular lipids were reduced by mild hypoxia by 18%, while in controls only, metformin administration further reduced intracellular lipids (20% O2) by 36%. Finally, palmitate oxidation was reduced by severe hypoxia, while metformin treatment reduced non-mitochondrial O2 consumption, palmitate oxidation, and proton leak at all O2 levels. Hypoxia directly reduced FFA uptake and intracellular lipids uptake in myotubes, at least partially, due to the reduction in CD36 transporters. Metformin, but not GW501516, can increase FFA uptake and SCL27A4 expression under mild hypoxia. Described effects might contribute to elevated plasma FFA levels and metabolic derangements in OSA.
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Affiliation(s)
- Martina Musutova
- Department for the Study of Obesity and Diabetes, Third Faculty of Medicine, Charles University, Prague, Czechia
| | - Moustafa Elkalaf
- Department of Biochemistry, Cell and Molecular Biology, Third Faculty of Medicine, Charles University, Prague, Czechia
| | - Natalie Klubickova
- Department for the Study of Obesity and Diabetes, Third Faculty of Medicine, Charles University, Prague, Czechia
| | - Michal Koc
- Department for the Study of Obesity and Diabetes, Third Faculty of Medicine, Charles University, Prague, Czechia
| | - Stanislav Povysil
- Department for the Study of Obesity and Diabetes, Third Faculty of Medicine, Charles University, Prague, Czechia
| | - Jan Rambousek
- Department for the Study of Obesity and Diabetes, Third Faculty of Medicine, Charles University, Prague, Czechia
| | - Beatriz Volckaert
- Department for the Study of Obesity and Diabetes, Third Faculty of Medicine, Charles University, Prague, Czechia
| | - Frantisek Duska
- Department of Anesthesiology and Intensive Care, Third Faculty of Medicine, Charles University, Prague, Czechia
| | - Minh Duc Trinh
- Department for the Study of Obesity and Diabetes, Third Faculty of Medicine, Charles University, Prague, Czechia
| | - Martin Kalous
- Department of Cell Biology, Faculty of Science, Charles University, Prague, Czechia
| | - Jan Trnka
- Department of Biochemistry, Cell and Molecular Biology, Third Faculty of Medicine, Charles University, Prague, Czechia
| | - Kamila Balusikova
- Division of Cell and Molecular Biology, Third Faculty of Medicine, Department of Biochemistry, Cell and Molecular Biology & Center for Research of Diabetes, Metabolism and Nutrition, Charles University, Prague, Czechia
| | - Jan Kovar
- Division of Cell and Molecular Biology, Third Faculty of Medicine, Department of Biochemistry, Cell and Molecular Biology & Center for Research of Diabetes, Metabolism and Nutrition, Charles University, Prague, Czechia
| | - Jan Polak
- Department for the Study of Obesity and Diabetes, Third Faculty of Medicine, Charles University, Prague, Czechia
- *Correspondence: Jan Polak
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Abstract
The Himalayan Sherpas, a human population of Tibetan descent, are highly adapted to life in the hypobaric hypoxia of high altitude. Mechanisms involving enhanced tissue oxygen delivery in comparison to Lowlander populations have been postulated to play a role in such adaptation. Whether differences in tissue oxygen utilization (i.e., metabolic adaptation) underpin this adaptation is not known, however. We sought to address this issue, applying parallel molecular, biochemical, physiological, and genetic approaches to the study of Sherpas and native Lowlanders, studied before and during exposure to hypobaric hypoxia on a gradual ascent to Mount Everest Base Camp (5,300 m). Compared with Lowlanders, Sherpas demonstrated a lower capacity for fatty acid oxidation in skeletal muscle biopsies, along with enhanced efficiency of oxygen utilization, improved muscle energetics, and protection against oxidative stress. This adaptation appeared to be related, in part, to a putatively advantageous allele for the peroxisome proliferator-activated receptor A (PPARA) gene, which was enriched in the Sherpas compared with the Lowlanders. Our findings suggest that metabolic adaptations underpin human evolution to life at high altitude, and could have an impact upon our understanding of human diseases in which hypoxia is a feature.
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