1
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Baum O. Expression of neuronal NO synthase α- and β-isoforms in skeletal muscle of mice. Biochem J 2024; 481:601-613. [PMID: 38592741 DOI: 10.1042/bcj20230458] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Revised: 03/27/2024] [Accepted: 04/09/2024] [Indexed: 04/10/2024]
Abstract
Knowledge of the primary structure of neuronal NO synthase (nNOS) in skeletal muscle is still conflicting and needs further clarification. To elucidate the expression patterns of nNOS isoforms at both mRNA and protein level, systematic reverse transcription (RT)-PCR and epitope mapping by qualitative immunoblot analysis on skeletal muscle of C57/BL6 mice were performed. The ability of the nNOS isoforms to form aggregates was characterized by native low-temperature polyacrylamide electrophoresis (LT-PAGE). The molecular analysis was focused on the rectus femoris (RF) muscle, a skeletal muscle with a nearly balanced ratio of nNOS α- and β-isoforms. RT-PCR amplificates from RF muscles showed exclusive exon-1d mRNA expression, either with or without exon-μ. Epitope mapping demonstrated the simultaneous expression of the nNOS splice variants α/μ, α/non-μ, β/μ and β/non-μ. Furthermore, immunoblotting suggests that the transition between nNOS α- and β-isoforms lies within exon-3. In LT-PAGE, three protein nNOS associated aggregates were detected in homogenates of RF muscle and tibialis anterior muscle: a 320 kDa band containing nNOS α-isoforms, while 250 and 300 kDa bands consist of nNOS β-isoforms that form homodimers or heterodimers with non-nNOS proteins.
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Affiliation(s)
- Oliver Baum
- Institute of Physiology, Charité - Universitätsmedizin Berlin, Charitéplatz 1, D-10117 Berlin, Germany
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2
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Margaritelis NV, Paschalis V, Theodorou AA, Kyparos A, Nikolaidis MG. Redox basis of exercise physiology. Redox Biol 2020; 35:101499. [PMID: 32192916 PMCID: PMC7284946 DOI: 10.1016/j.redox.2020.101499] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 02/20/2020] [Accepted: 03/05/2020] [Indexed: 12/15/2022] Open
Abstract
Redox reactions control fundamental processes of human biology. Therefore, it is safe to assume that the responses and adaptations to exercise are, at least in part, mediated by redox reactions. In this review, we are trying to show that redox reactions are the basis of exercise physiology by outlining the redox signaling pathways that regulate four characteristic acute exercise-induced responses (muscle contractile function, glucose uptake, blood flow and bioenergetics) and four chronic exercise-induced adaptations (mitochondrial biogenesis, muscle hypertrophy, angiogenesis and redox homeostasis). Based on our analysis, we argue that redox regulation should be acknowledged as central to exercise physiology.
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Affiliation(s)
- N V Margaritelis
- Department of Physical Education and Sport Science at Serres, Aristotle University of Thessaloniki, Thessaloniki, Greece; Dialysis Unit, 424 General Military Hospital of Thessaloniki, Thessaloniki, Greece.
| | - V Paschalis
- School of Physical Education and Sport Science, National and Kapodistrian University of Athens, Athens, Greece
| | - A A Theodorou
- Department of Life Sciences, School of Sciences, European University Cyprus, Nicosia, Cyprus
| | - A Kyparos
- Department of Physical Education and Sport Science at Serres, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - M G Nikolaidis
- Department of Physical Education and Sport Science at Serres, Aristotle University of Thessaloniki, Thessaloniki, Greece.
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3
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Christiansen D, Eibye KH, Hostrup M, Bangsbo J. Blood flow-restricted training enhances thigh glucose uptake during exercise and muscle antioxidant function in humans. Metabolism 2019; 98:1-15. [PMID: 31199953 DOI: 10.1016/j.metabol.2019.06.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Revised: 05/31/2019] [Accepted: 06/05/2019] [Indexed: 10/26/2022]
Abstract
This study examined the effects of blood-flow-restricted (BFR)-training on thigh glucose uptake at rest and during exercise in humans and the muscular mechanisms involved. Ten active men (~25 y; VO2max ~50 mL/kg/min) completed six weeks of training, where one leg trained with BFR (cuff pressure: ~180 mmHg) and the other leg without BFR. Before and after training, thigh glucose uptake was determined at rest and during exercise at 25% and 90% of leg incremental peak power output by sampling of femoral arterial and venous blood and measurement of femoral arterial blood flow. Furthermore, resting muscle samples were collected. After training, thigh glucose uptake during exercise was higher than before training only in the BFR-trained leg (p < 0.05) due to increased glucose extraction (p < 0.05). Further, BFR-training substantially improved time to exhaustion during exhaustive exercise (11 ± 5% vs. CON-leg; p = 0.001). After but not before training, NAC infusion attenuated (~50-100%) leg net glucose uptake and extraction during exercise only in the BFR-trained leg, which coincided with an increased muscle abundance of Cu/Zn-SOD (39%), GPX-1 (29%), GLUT4 (28%), and nNOS (18%) (p < 0.05). Training did not affect Mn-SOD, catalase, and VEGF abundance in either leg (p > 0.05), although Mn-SOD was higher in BFR-leg vs. CON-leg after training (p < 0.05). The ratios of p-AMPK-Thr172/AMPK and p-ACC-Ser79/ACC, and p-ACC-Ser79, remained unchanged in both legs (p > 0.05), despite a higher p-AMPK-Thr172 in BFR-leg after training (38%; p < 0.05). In conclusion, BFR-training enhances glucose uptake by exercising muscles in humans probably due to an increase in antioxidant function, GLUT4 abundance, and/or NO availability.
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Affiliation(s)
- Danny Christiansen
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports (NEXS), University of Copenhagen, 2100 Copenhagen Ø, Denmark.
| | - Kasper H Eibye
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports (NEXS), University of Copenhagen, 2100 Copenhagen Ø, Denmark
| | - Morten Hostrup
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports (NEXS), University of Copenhagen, 2100 Copenhagen Ø, Denmark
| | - Jens Bangsbo
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports (NEXS), University of Copenhagen, 2100 Copenhagen Ø, Denmark
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4
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Meza CA, La Favor JD, Kim DH, Hickner RC. Endothelial Dysfunction: Is There a Hyperglycemia-Induced Imbalance of NOX and NOS? Int J Mol Sci 2019; 20:ijms20153775. [PMID: 31382355 PMCID: PMC6696313 DOI: 10.3390/ijms20153775] [Citation(s) in RCA: 175] [Impact Index Per Article: 35.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Revised: 07/29/2019] [Accepted: 07/31/2019] [Indexed: 02/07/2023] Open
Abstract
NADPH oxidases (NOX) are enzyme complexes that have received much attention as key molecules in the development of vascular dysfunction. NOX have the primary function of generating reactive oxygen species (ROS), and are considered the main source of ROS production in endothelial cells. The endothelium is a thin monolayer that lines the inner surface of blood vessels, acting as a secretory organ to maintain homeostasis of blood flow. The enzymatic production of nitric oxide (NO) by endothelial NO synthase (eNOS) is critical in mediating endothelial function, and oxidative stress can cause dysregulation of eNOS and endothelial dysfunction. Insulin is a stimulus for increases in blood flow and endothelium-dependent vasodilation. However, cardiovascular disease and type 2 diabetes are characterized by poor control of the endothelial cell redox environment, with a shift toward overproduction of ROS by NOX. Studies in models of type 2 diabetes demonstrate that aberrant NOX activation contributes to uncoupling of eNOS and endothelial dysfunction. It is well-established that endothelial dysfunction precedes the onset of cardiovascular disease, therefore NOX are important molecular links between type 2 diabetes and vascular complications. The aim of the current review is to describe the normal, healthy physiological mechanisms involved in endothelial function, and highlight the central role of NOX in mediating endothelial dysfunction when glucose homeostasis is impaired.
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Affiliation(s)
- Cesar A Meza
- Department of Nutrition, Food & Exercise Sciences, Florida State University, Tallahassee, FL 32306, USA
| | - Justin D La Favor
- Department of Nutrition, Food & Exercise Sciences, Florida State University, Tallahassee, FL 32306, USA
| | - Do-Houn Kim
- Department of Nutrition, Food & Exercise Sciences, Florida State University, Tallahassee, FL 32306, USA
| | - Robert C Hickner
- Department of Nutrition, Food & Exercise Sciences, Florida State University, Tallahassee, FL 32306, USA.
- Institute of Sports Sciences and Medicine, College of Human Sciences, Florida State University, Tallahassee, FL 32306, USA.
- Department of Biokinetics, Exercise and Leisure Sciences, School of Health Sciences, University of KwaZulu-Natal, Westville 4041, South Africa.
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5
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Normal increases in insulin-stimulated glucose uptake after ex vivo contraction in neuronal nitric oxide synthase mu (nNOSμ) knockout mice. Pflugers Arch 2019; 471:961-969. [DOI: 10.1007/s00424-019-02268-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 02/20/2019] [Accepted: 02/26/2019] [Indexed: 11/25/2022]
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6
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Kerris JP, Betik AC, Li J, McConell GK. Passive stretch regulates skeletal muscle glucose uptake independent of nitric oxide synthase. J Appl Physiol (1985) 2018; 126:239-245. [PMID: 30236052 DOI: 10.1152/japplphysiol.00368.2018] [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] [Indexed: 12/13/2022] Open
Abstract
Skeletal muscle contraction increases glucose uptake via an insulin-independent mechanism. Signaling pathways arising from mechanical strain are activated during muscle contractions, and mechanical strain in the form of passive stretching stimulates glucose uptake. However, the exact mechanisms regulating stretch-stimulated glucose uptake are not known. Since nitric oxide synthase (NOS) has been implicated in the regulation of glucose uptake during ex vivo and in situ muscle contractions and during exercise, and NO is increased with stretch, we examined whether the increase in muscle glucose uptake during stretching involves NOS. We passively stretched isolated extensor digitorum longus muscles (15 min at ~100-130 mN) from control mice and mice lacking either neuronal NOSµ (nNOSµ) or endothelial NOS (eNOS) isoforms, as well as used pharmacological inhibitors of NOS. Stretch significantly increased muscle glucose uptake appoximately twofold ( P < 0.05), and this was unaffected by the presence of the NOS inhibitors NG-monomethyl-l-arginine (100 µM) or NG-nitro-l-arginine methyl ester (100 µM). Similarly, stretch-stimulated glucose uptake was not attenuated by deletion of either eNOS or nNOSµ isoforms. Furthermore, stretching failed to increase skeletal muscle NOS enzymatic activity above resting levels. These data clearly demonstrate that stretch-stimulated skeletal muscle glucose uptake is not dependent on NOS. NEW & NOTEWORTHY Passive stretching is known to activate muscle glucose uptake through mechanisms that partially overlap with contraction. We report that genetic knockout of endothelial nitric oxide synthase (NOS) or neuronal NOS or pharmacological NOS inhibition does not affect stretch-stimulated glucose uptake. Passive stretch failed to increase NOS activity above resting levels. This information is important for the study of signaling pathways that regulate stretch-stimulated glucose uptake and indicate that NOS should be excluded as a potential signaling factor in this regard.
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Affiliation(s)
- Jarrod P Kerris
- Institute for Health and Sport, Victoria University , Melbourne , Australia.,College of Sport and Exercise Science, Victoria University , Melbourne , Australia
| | - Andrew C Betik
- Institute for Health and Sport, Victoria University , Melbourne , Australia.,College of Health and Biomedicine, Victoria University , Melbourne , Australia
| | - Jinhua Li
- Department of Anatomy and Developmental Biology, Monash Biomedicine Discovery Institute, Monash University , Clayton , Australia
| | - Glenn K McConell
- Institute for Health and Sport, Victoria University , Melbourne , Australia.,College of Sport and Exercise Science, Victoria University , Melbourne , Australia
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7
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Edwards TM, Hamlin HJ. Reproductive endocrinology of environmental nitrate. Gen Comp Endocrinol 2018; 265:31-40. [PMID: 29577898 DOI: 10.1016/j.ygcen.2018.03.021] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Revised: 03/19/2018] [Accepted: 03/20/2018] [Indexed: 12/19/2022]
Abstract
Nitrate is a widespread contaminant of aquatic ecosystems and drinking water. It is also broadly active in organismal physiology, and as such, has the potential to both enhance and disrupt normal physiological function. In animals, nitrate is a proposed endocrine disrupter that is converted in vivo to nitrite and nitric oxide. Nitric oxide, in particular, is a potent cell signaling molecule that participates in diverse biological pathways and events. Here, we review in vivo nitrate cycling and downstream mechanistic physiology, with an emphasis on reproductive outcomes. However, in many cases, the research produces contradictory results, in part because there is good evidence that nitrate follows a non-monotonic dose-response curve. This conundrum highlights an array of opportunities for scientists from different fields to collaborate for a full understanding of nitrate physiology. Opposing conclusions are especially likely when in vivo/in vitro, long term/short term, high dose/low dose, or hypoxia/normoxia studies are compared. We conclude that in vivo studies are most appropriate for testing an organism's integrated endocrine response to nitrate. Based on the limited available studies, there is a generalized trend that shorter term studies (less than 1 month) or studies involving low doses (≤5 mg/L NO3-N) cause steroid hormone levels to decline. Studies that last more than a month and/or involve higher, but still environmentally relevant, exposures (>50-100 mg/L NO3-N) cause steroid hormone levels to increase. Very high nitrate doses (>500 mg/L NO3-N) are cytotoxic in many species. Hypoxia and acidity are likely to intensify the effects of nitrate. For study design, degree of study animal reproductive maturity or activity is important, with immature/reproductively quiescent animals responding to nitrate differently, compared with reproductively active animals. A detailed table of studies is presented.
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Affiliation(s)
- Thea M Edwards
- Department of Biology, University of the South, Sewanee, TN, USA.
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8
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Zhang X, Hiam D, Hong YH, Zulli A, Hayes A, Rattigan S, McConell GK. Nitric oxide is required for the insulin sensitizing effects of contraction in mouse skeletal muscle. J Physiol 2017; 595:7427-7439. [PMID: 29071734 DOI: 10.1113/jp275133] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Accepted: 10/18/2017] [Indexed: 01/15/2023] Open
Abstract
KEY POINTS People with insulin resistance or type 2 diabetes can substantially increase their skeletal muscle glucose uptake during exercise and insulin sensitivity after exercise. Skeletal muscle nitric oxide (NO) is important for glucose uptake during exercise, although how prior exercise increases insulin sensitivity is unclear. In the present study, we examined whether NO is necessary for normal increases in skeletal muscle insulin sensitivity after contraction ex vivo in mouse muscle. The present study uncovers, for the first time, a novel role for NO in the insulin sensitizing effects of ex vivo contraction, which is independent of blood flow. ABSTRACT The factors regulating the increase in skeletal muscle insulin sensitivity after exercise are unclear. We examined whether nitric oxide (NO) is required for the increase in insulin sensitivity after ex vivo contractions. Isolated C57BL/6J mouse EDL muscles were contracted for 10 min or remained at rest (basal) with or without the NO synthase (NOS) inhibition (NG -monomethyl-l-arginine; l-NMMA; 100 μm). Then, 3.5 h post contraction/basal, muscles were exposed to saline or insulin (120 μU ml-1 ) with or without l-NMMA during the last 30 min. l-NMMA had no effect on basal skeletal muscle glucose uptake. The increase in muscle glucose uptake with insulin (57%) was significantly (P < 0.05) greater after prior contraction (140% increase). NOS inhibition during the contractions had no effect on this insulin-sensitizing effect of contraction, whereas NOS inhibition during insulin prevented the increase in skeletal muscle insulin sensitivity post-contraction. Soluble guanylate cyclase inhibition, protein kinase G (PKG) inhibition or cyclic nucleotide phosphodiesterase inhibition each had no effect on the insulin-sensitizing effect of prior contraction. In conclusion, NO is required for increases in insulin sensitivity several hours after contraction of mouse skeletal muscle via a cGMP/PKG independent pathway.
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Affiliation(s)
- Xinmei Zhang
- Institute of Sport, Exercise and Active Living (ISEAL), College of Sport and Exercise Science, Victoria University, Melbourne, VIC, Australia.,School of Health and Biomedical Sciences, RMIT University, Melbourne, VIC, Australia
| | - Danielle Hiam
- Institute of Sport, Exercise and Active Living (ISEAL), College of Sport and Exercise Science, Victoria University, Melbourne, VIC, Australia
| | - Yet-Hoi Hong
- Institute of Sport, Exercise and Active Living (ISEAL), College of Sport and Exercise Science, Victoria University, Melbourne, VIC, Australia
| | - Anthony Zulli
- College of Health and Biomedicine, Victoria University, Melbourne, VIC, Australia
| | - Alan Hayes
- Institute of Sport, Exercise and Active Living (ISEAL), College of Sport and Exercise Science, Victoria University, Melbourne, VIC, Australia.,College of Health and Biomedicine, Victoria University, Melbourne, VIC, Australia
| | - Stephen Rattigan
- Menzies Institute for Medical Research, University of Tasmania, Hobart, TAS, Australia
| | - Glenn K McConell
- Institute of Sport, Exercise and Active Living (ISEAL), College of Sport and Exercise Science, Victoria University, Melbourne, VIC, Australia.,College of Health and Biomedicine, Victoria University, Melbourne, VIC, Australia
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9
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Timpani CA, Trewin AJ, Stojanovska V, Robinson A, Goodman CA, Nurgali K, Betik AC, Stepto N, Hayes A, McConell GK, Rybalka E. Attempting to Compensate for Reduced Neuronal Nitric Oxide Synthase Protein with Nitrate Supplementation Cannot Overcome Metabolic Dysfunction but Rather Has Detrimental Effects in Dystrophin-Deficient mdx Muscle. Neurotherapeutics 2017; 14:429-446. [PMID: 27921261 PMCID: PMC5398978 DOI: 10.1007/s13311-016-0494-7] [Citation(s) in RCA: 23] [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] [Indexed: 11/26/2022] Open
Abstract
Duchenne muscular dystrophy arises from the loss of dystrophin and is characterized by calcium dysregulation, muscular atrophy, and metabolic dysfunction. The secondary reduction of neuronal nitric oxide synthase (nNOS) from the sarcolemma reduces NO production and bioavailability. As NO modulates glucose uptake, metabolism, and mitochondrial bioenergetics, we investigated whether an 8-week nitrate supplementation regimen could overcome metabolic dysfunction in the mdx mouse. Dystrophin-positive control (C57BL/10) and dystrophin-deficient mdx mice were supplemented with sodium nitrate (85 mg/l) in drinking water. Following the supplementation period, extensor digitorum longus and soleus were excised and radioactive glucose uptake was measured at rest (basal) and during contraction. Gastrocnemius was excised and mitochondrial respiration was measured using the Oroboros Oxygraph. Tibialis anterior was analyzed immunohistochemically for the presence of dystrophin, nNOS, nitrotyrosine, IgG and CD45+ cells, and histologically to assess areas of damage and regeneration. Glucose uptake in the basal and contracting states was normal in unsupplemented mdx muscles but was reduced following nitrate supplementation in mdx muscles only. The mitochondrial utilization of substrates was also impaired in mdx gastrocnemius during phosphorylating and maximal uncoupled respiration, and nitrate could not improve respiration in mdx muscle. Although nitrate supplementation reduced mitochondrial hydrogen peroxide emission, it induced mitochondrial uncoupling in red gastrocnemius, increased muscle fiber peroxynitrite (nitrotyrosine), and promoted skeletal muscle damage. Our novel data suggest that despite lower nNOS protein expression and likely lower NO production in mdx muscle, enhancing NO production with nitrate supplementation in these mice has detrimental effects on skeletal muscle. This may have important relevance for those with DMD.
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Affiliation(s)
- Cara A Timpani
- Centre for Chronic Disease, College of Health & Biomedicine, Victoria University, Melbourne, Victoria, 8001, Australia
| | - Adam J Trewin
- Institute of Sport, Exercise & Active Living (ISEAL), Victoria University, Melbourne, Victoria, 8001, Australia
| | - Vanesa Stojanovska
- Centre for Chronic Disease, College of Health & Biomedicine, Victoria University, Melbourne, Victoria, 8001, Australia
| | - Ainsley Robinson
- Centre for Chronic Disease, College of Health & Biomedicine, Victoria University, Melbourne, Victoria, 8001, Australia
| | - Craig A Goodman
- Centre for Chronic Disease, College of Health & Biomedicine, Victoria University, Melbourne, Victoria, 8001, Australia
- Institute of Sport, Exercise & Active Living (ISEAL), Victoria University, Melbourne, Victoria, 8001, Australia
- Australian Institute of Musculoskeletal Science (AIMSS), Western Health, Melbourne, Victoria, 3021, Australia
| | - Kulmira Nurgali
- Centre for Chronic Disease, College of Health & Biomedicine, Victoria University, Melbourne, Victoria, 8001, Australia
| | - Andrew C Betik
- Centre for Chronic Disease, College of Health & Biomedicine, Victoria University, Melbourne, Victoria, 8001, Australia
- Institute of Sport, Exercise & Active Living (ISEAL), Victoria University, Melbourne, Victoria, 8001, Australia
| | - Nigel Stepto
- Institute of Sport, Exercise & Active Living (ISEAL), Victoria University, Melbourne, Victoria, 8001, Australia
| | - Alan Hayes
- Centre for Chronic Disease, College of Health & Biomedicine, Victoria University, Melbourne, Victoria, 8001, Australia
- Institute of Sport, Exercise & Active Living (ISEAL), Victoria University, Melbourne, Victoria, 8001, Australia
- Australian Institute of Musculoskeletal Science (AIMSS), Western Health, Melbourne, Victoria, 3021, Australia
| | - Glenn K McConell
- Institute of Sport, Exercise & Active Living (ISEAL), Victoria University, Melbourne, Victoria, 8001, Australia
- Australian Institute of Musculoskeletal Science (AIMSS), Western Health, Melbourne, Victoria, 3021, Australia
| | - Emma Rybalka
- Centre for Chronic Disease, College of Health & Biomedicine, Victoria University, Melbourne, Victoria, 8001, Australia.
- Institute of Sport, Exercise & Active Living (ISEAL), Victoria University, Melbourne, Victoria, 8001, Australia.
- Australian Institute of Musculoskeletal Science (AIMSS), Western Health, Melbourne, Victoria, 3021, Australia.
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10
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Sylow L, Kleinert M, Richter EA, Jensen TE. Exercise-stimulated glucose uptake - regulation and implications for glycaemic control. Nat Rev Endocrinol 2017; 13:133-148. [PMID: 27739515 DOI: 10.1038/nrendo.2016.162] [Citation(s) in RCA: 257] [Impact Index Per Article: 36.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Skeletal muscle extracts glucose from the blood to maintain demand for carbohydrates as an energy source during exercise. Such uptake involves complex molecular signalling processes that are distinct from those activated by insulin. Exercise-stimulated glucose uptake is preserved in insulin-resistant muscle, emphasizing exercise as a therapeutic cornerstone among patients with metabolic diseases such as diabetes mellitus. Exercise increases uptake of glucose by up to 50-fold through the simultaneous stimulation of three key steps: delivery, transport across the muscle membrane and intracellular flux through metabolic processes (glycolysis and glucose oxidation). The available data suggest that no single signal transduction pathway can fully account for the regulation of any of these key steps, owing to redundancy in the signalling pathways that mediate glucose uptake to ensure maintenance of muscle energy supply during physical activity. Here, we review the molecular mechanisms that regulate the movement of glucose from the capillary bed into the muscle cell and discuss what is known about their integrated regulation during exercise. Novel developments within the field of mass spectrometry-based proteomics indicate that the known regulators of glucose uptake are only the tip of the iceberg. Consequently, many exciting discoveries clearly lie ahead.
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Affiliation(s)
- Lykke Sylow
- Molecular Physiology Group, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Maximilian Kleinert
- Molecular Physiology Group, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
- Institute for Diabetes and Obesity, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany
| | - Erik A Richter
- Molecular Physiology Group, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Thomas E Jensen
- Molecular Physiology Group, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
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11
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Moon Y, Cao Y, Zhu J, Xu Y, Balkan W, Buys ES, Diaz F, Kerrick WG, Hare JM, Percival JM. GSNOR Deficiency Enhances In Situ Skeletal Muscle Strength, Fatigue Resistance, and RyR1 S-Nitrosylation Without Impacting Mitochondrial Content and Activity. Antioxid Redox Signal 2017; 26:165-181. [PMID: 27412893 PMCID: PMC5278832 DOI: 10.1089/ars.2015.6548] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
AIM Nitric oxide (NO) plays important, but incompletely defined roles in skeletal muscle. NO exerts its regulatory effects partly though S-nitrosylation, which is balanced by denitrosylation by enzymes such as S-nitrosoglutathione reductase (GSNOR), whose functions in skeletal muscle remain to be fully deciphered. RESULTS GSNOR null (GSNOR-/-) tibialis anterior (TA) muscles showed normal growth and were stronger and more fatigue resistant than controls in situ. However, GSNOR-/- lumbrical muscles showed normal contractility and Ca2+ handling in vitro, suggesting important differences in GSNOR function between muscles or between in vitro and in situ environments. GSNOR-/- TA muscles exhibited normal mitochondrial content, and capillary densities, but reduced type IIA fiber content. GSNOR inhibition did not impact mitochondrial respiratory complex I, III, or IV activities. These findings argue that enhanced GSNOR-/- TA contractility is not driven by changes in mitochondrial content or activity, fiber type, or blood vessel density. However, loss of GSNOR led to RyR1 hypernitrosylation, which is believed to increase muscle force output under physiological conditions. cGMP synthesis by soluble guanylate cyclase (sGC) was decreased in resting GSNOR-/- muscle and was more responsive to agonist (DETANO, BAY 41, and BAY 58) stimulation, suggesting that GSNOR modulates cGMP production in skeletal muscle. INNOVATION GSNOR may act as a "brake" on skeletal muscle contractile performance under physiological conditions by modulating nitrosylation/denitrosylation balance. CONCLUSIONS GSNOR may play important roles in skeletal muscle contractility, RyR1 S-nitrosylation, fiber type specification, and sGC activity. Antioxid. Redox Signal. 26, 165-181.
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Affiliation(s)
- Younghye Moon
- 1 Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine , Miami, Florida
| | - Yenong Cao
- 1 Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine , Miami, Florida.,2 The Interdisciplinary Stem Cell Institute, University of Miami Miller School of Medicine , Miami, Florida
| | - Jingjing Zhu
- 1 Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine , Miami, Florida
| | - Yuanyuan Xu
- 3 Department of Physiology and Biophysics, University of Miami Miller School of Medicine , Miami, Florida
| | - Wayne Balkan
- 2 The Interdisciplinary Stem Cell Institute, University of Miami Miller School of Medicine , Miami, Florida.,4 Department of Medicine, University of Miami Miller School of Medicine , Miami, Florida
| | - Emmanuel S Buys
- 5 Department of Anesthesia, Critical Care and Pain Medicine, Anesthesia Center for Critical Care Research , Harvard Medical School, Massachusetts General Hospital Boston, Boston, Massachusetts
| | - Francisca Diaz
- 6 Department of Neurology, University of Miami Miller School of Medicine , Miami, Florida
| | - W Glenn Kerrick
- 3 Department of Physiology and Biophysics, University of Miami Miller School of Medicine , Miami, Florida
| | - Joshua M Hare
- 1 Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine , Miami, Florida.,2 The Interdisciplinary Stem Cell Institute, University of Miami Miller School of Medicine , Miami, Florida.,4 Department of Medicine, University of Miami Miller School of Medicine , Miami, Florida
| | - Justin M Percival
- 1 Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine , Miami, Florida
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12
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Mason SA, Morrison D, McConell GK, Wadley GD. Muscle redox signalling pathways in exercise. Role of antioxidants. Free Radic Biol Med 2016; 98:29-45. [PMID: 26912034 DOI: 10.1016/j.freeradbiomed.2016.02.022] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2015] [Revised: 02/05/2016] [Accepted: 02/17/2016] [Indexed: 01/01/2023]
Abstract
Recent research highlights the importance of redox signalling pathway activation by contraction-induced reactive oxygen species (ROS) and nitric oxide (NO) in normal exercise-related cellular and molecular adaptations in skeletal muscle. In this review, we discuss some potentially important redox signalling pathways in skeletal muscle that are involved in acute and chronic responses to contraction and exercise. Specifically, we discuss redox signalling implicated in skeletal muscle contraction force, mitochondrial biogenesis and antioxidant enzyme induction, glucose uptake and muscle hypertrophy. Furthermore, we review evidence investigating the impact of major exogenous antioxidants on these acute and chronic responses to exercise. Redox signalling pathways involved in adaptive responses in skeletal muscle to exercise are not clearly elucidated at present, and further research is required to better define important signalling pathways involved. Evidence of beneficial or detrimental effects of specific antioxidant compounds on exercise adaptations in muscle is similarly limited, particularly in human subjects. Future research is required to not only investigate effects of specific antioxidant compounds on skeletal muscle exercise adaptations, but also to better establish mechanisms of action of specific antioxidants in vivo. Although we feel it remains somewhat premature to make clear recommendations in relation to application of specific antioxidant compounds in different exercise settings, a bulk of evidence suggests that N-acetylcysteine (NAC) is ergogenic through its effects on maintenance of muscle force production during sustained fatiguing events. Nevertheless, a current lack of evidence from studies using performance tests representative of athletic competition and a potential for adverse effects with high doses (>70mg/kg body mass) warrants caution in its use for performance enhancement. In addition, evidence implicates high dose vitamin C (1g/day) and E (≥260 IU/day) supplementation in impairments to some skeletal muscle cellular adaptations to chronic exercise training. Thus, determining the utility of antioxidant supplementation in athletes likely requires a consideration of training and competition periodization cycles of athletes in addition to type, dose and duration of antioxidant supplementation.
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Affiliation(s)
- Shaun A Mason
- Centre for Physical Activity and Nutrition (C-PAN) Research, School of Exercise and Nutrition Sciences, Deakin University, Geelong, Victoria, Australia
| | - Dale Morrison
- Centre for Physical Activity and Nutrition (C-PAN) Research, School of Exercise and Nutrition Sciences, Deakin University, Geelong, Victoria, Australia
| | - Glenn K McConell
- Clinical Exercise Science Research Program, Institute for Sport, Exercise and Active Living (ISEAL), Victoria University, Melbourne, Victoria, Australia
| | - Glenn D Wadley
- Centre for Physical Activity and Nutrition (C-PAN) Research, School of Exercise and Nutrition Sciences, Deakin University, Geelong, Victoria, Australia.
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Hong YH, Yang C, Betik AC, Lee-Young RS, McConell GK. Skeletal muscle glucose uptake during treadmill exercise in neuronal nitric oxide synthase-μ knockout mice. Am J Physiol Endocrinol Metab 2016; 310:E838-45. [PMID: 27006199 DOI: 10.1152/ajpendo.00513.2015] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 03/17/2016] [Indexed: 11/22/2022]
Abstract
Nitric oxide influences intramuscular signaling that affects skeletal muscle glucose uptake during exercise. The role of the main NO-producing enzyme isoform activated during skeletal muscle contraction, neuronal nitric oxide synthase-μ (nNOSμ), in modulating glucose uptake has not been investigated in a physiological exercise model. In this study, conscious and unrestrained chronically catheterized nNOSμ(+/+) and nNOSμ(-/-) mice either remained at rest or ran on a treadmill at 17 m/min for 30 min. Both groups of mice demonstrated similar exercise capacity during a maximal exercise test to exhaustion (17.7 ± 0.6 vs. 15.9 ± 0.9 min for nNOSμ(+/+) and nNOSμ(-/-), respectively, P > 0.05). Resting and exercise blood glucose levels were comparable between the genotypes. Very low levels of NOS activity were detected in skeletal muscle from nNOSμ(-/-) mice, and exercise increased NOS activity only in nNOSμ(+/+) mice (4.4 ± 0.3 to 5.2 ± 0.4 pmol·mg(-1)·min(-1), P < 0.05). Exercise significantly increased glucose uptake in gastrocnemius muscle (5- to 7-fold) and, surprisingly, more so in nNOSμ(-/-) than in nNOSμ(+/+) mice (P < 0.05). This is in parallel with a greater increase in AMPK phosphorylation during exercise in nNOSμ(-/-) mice. In conclusion, nNOSμ is not essential for skeletal muscle glucose uptake during exercise, and the higher skeletal muscle glucose uptake during exercise in nNOSμ(-/-) mice may be due to compensatory increases in AMPK activation.
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Affiliation(s)
- Yet Hoi Hong
- College of Health and Biomedicine, Victoria University, Melbourne, Victoria, Australia; Clinical Exercise Science Program, Institute of Sport, Exercise and Active Living, Victoria University, Melbourne, Victoria, Australia; Department of Physiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia; and
| | - Christine Yang
- Cellular and Molecular Metabolism, Baker IDI Heart and Diabetes Institute, Melbourne, Victoria, Australia
| | - Andrew C Betik
- College of Health and Biomedicine, Victoria University, Melbourne, Victoria, Australia; Clinical Exercise Science Program, Institute of Sport, Exercise and Active Living, Victoria University, Melbourne, Victoria, Australia
| | - Robert S Lee-Young
- Cellular and Molecular Metabolism, Baker IDI Heart and Diabetes Institute, Melbourne, Victoria, Australia
| | - Glenn K McConell
- College of Health and Biomedicine, Victoria University, Melbourne, Victoria, Australia; Clinical Exercise Science Program, Institute of Sport, Exercise and Active Living, Victoria University, Melbourne, Victoria, Australia
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