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Voldstedlund CT, Sjøberg KA, Schlabs FL, Sigvardsen CM, Andersen NR, Holst JJ, Hartmann B, Wojtaszewski JFP, Kiens B, McConell GK, Richter EA. Exercise-induced increase in muscle insulin sensitivity in men is amplified when assessed using a meal test. Diabetologia 2024; 67:1386-1398. [PMID: 38662135 PMCID: PMC11153309 DOI: 10.1007/s00125-024-06148-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Accepted: 02/26/2024] [Indexed: 04/26/2024]
Abstract
AIMS/HYPOTHESIS Exercise has a profound effect on insulin sensitivity in skeletal muscle. The euglycaemic-hyperinsulinaemic clamp (EHC) is the gold standard for assessment of insulin sensitivity but it does not reflect the hyperglycaemia that occurs after eating a meal. In previous EHC investigations, it has been shown that the interstitial glucose concentration in muscle is decreased to a larger extent in previously exercised muscle than in rested muscle. This suggests that previously exercised muscle may increase its glucose uptake more than rested muscle if glucose supply is increased by hyperglycaemia. Therefore, we hypothesised that the exercise-induced increase in muscle insulin sensitivity would appear greater after eating a meal than previously observed with the EHC. METHODS Ten recreationally active men performed dynamic one-legged knee extensor exercise for 1 h. Following this, both femoral veins and one femoral artery were cannulated. Subsequently, 4 h after exercise, a solid meal followed by two liquid meals were ingested over 1 h and glucose uptake in the two legs was measured for 3 h. Muscle biopsies from both legs were obtained before the meal test and 90 min after the meal test was initiated. Data obtained in previous studies using the EHC (n=106 participants from 13 EHC studies) were used for comparison with the meal-test data obtained in this study. RESULTS Plasma glucose and insulin peaked 45 min after initiation of the meal test. Following the meal test, leg glucose uptake and glucose clearance increased twice as much in the exercised leg than in the rested leg; this difference is twice as big as that observed in previous investigations using EHCs. Glucose uptake in the rested leg plateaued after 15 min, alongside elevated muscle glucose 6-phosphate levels, suggestive of compromised muscle glucose metabolism. In contrast, glucose uptake in the exercised leg plateaued 45 min after initiation of the meal test and there were no signs of compromised glucose metabolism. Phosphorylation of the TBC1 domain family member 4 (TBC1D4; p-TBC1D4Ser704) and glycogen synthase activity were greater in the exercised leg compared with the rested leg. Muscle interstitial glucose concentration increased with ingestion of meals, although it was 16% lower in the exercised leg than in the rested leg. CONCLUSIONS/INTERPRETATION Hyperglycaemia after meal ingestion results in larger differences in muscle glucose uptake between rested and exercised muscle than previously observed during EHCs. These findings indicate that the ability of exercise to increase insulin-stimulated muscle glucose uptake is even greater when evaluated with a meal test than has previously been shown with EHCs.
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Affiliation(s)
- Christian T Voldstedlund
- August Krogh Section for Molecular Physiology, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Kim A Sjøberg
- August Krogh Section for Molecular Physiology, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Farina L Schlabs
- August Krogh Section for Molecular Physiology, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Casper M Sigvardsen
- August Krogh Section for Molecular Physiology, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Nicoline R Andersen
- August Krogh Section for Molecular Physiology, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jens J Holst
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Bolette Hartmann
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jørgen F P Wojtaszewski
- August Krogh Section for Molecular Physiology, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Bente Kiens
- August Krogh Section for Molecular Physiology, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Glenn K McConell
- August Krogh Section for Molecular Physiology, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark.
- Institute for Health and Sport, Victoria University, Melbourne, VIC, Australia.
| | - Erik A Richter
- August Krogh Section for Molecular Physiology, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark.
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Sabaratnam R, Kristensen JM, Pedersen AJT, Kruse R, Handberg A, Wojtaszewski JFP, Højlund K. Acute Exercise Increases GDF15 and Unfolded Protein Response/Integrated Stress Response in Muscle in Type 2 Diabetes. J Clin Endocrinol Metab 2024; 109:1754-1764. [PMID: 38242693 DOI: 10.1210/clinem/dgae032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Revised: 12/27/2023] [Accepted: 01/16/2024] [Indexed: 01/21/2024]
Abstract
CONTEXT Regular exercise is a key prevention strategy for obesity and type 2 diabetes (T2D). Exerkines secreted in response to exercise or recovery may contribute to improved systemic metabolism. Conversely, an impaired exerkine response to exercise and recovery may contribute to cardiometabolic diseases. OBJECTIVE We investigated if the exercise-induced regulation of the exerkine, growth differentiation factor 15 (GDF15) and its putative upstream regulators of the unfolded protein response (UPR)/integrated stress response (ISR) is impaired in skeletal muscle in patients with T2D compared with weight-matched glucose-tolerant men. METHODS Thirteen male patients with T2D and 14 age- and weight-matched overweight/obese glucose-tolerant men exercised at 70% of VO2max for 1 hour. Blood and skeletal muscle biopsies were sampled before, immediately after, and 3 hours into recovery. Serum and muscle transcript levels of GDF15 and key markers of UPR/ISR were determined. Additionally, protein/phosphorylation levels of key regulators in UPR/ISR were investigated. RESULTS Acute exercise increased muscle gene expression and serum GDF15 levels in both groups. In recovery, muscle expression of GDF15 decreased toward baseline, whereas serum GDF15 remained elevated. In both groups, acute exercise increased the expression of UPR/ISR markers, including ATF4, CHOP, EIF2K3 (encoding PERK), and PPP1R15A (encoding GADD34), of which only CHOP remained elevated 3 hours into recovery. Downstream molecules of the UPR/ISR including XBP1-U, XBP1-S, and EDEM1 were increased with exercise and 3 hours into recovery in both groups. The phosphorylation levels of eIF2α-Ser51, a common marker of unfolded protein response (UPR) and ISR, increased immediately after exercise in controls, but decreased 3 hours into recovery in both groups. CONCLUSION In conclusion, exercise-induced regulation of GDF15 and key markers of UPR/ISR are not compromised in patients with T2D compared with weight-matched controls.
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Affiliation(s)
- Rugivan Sabaratnam
- Department of Clinical Research & Department of Molecular Medicine, University of Southern Denmark, DK-5230 Odense M, Denmark
- Steno Diabetes Center Odense, Odense University Hospital, DK-5000 Odense C, Denmark
| | - Jonas M Kristensen
- Department of Clinical Research & Department of Molecular Medicine, University of Southern Denmark, DK-5230 Odense M, Denmark
- Steno Diabetes Center Odense, Odense University Hospital, DK-5000 Odense C, Denmark
- The August Krogh Section for Molecular Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - Andreas J T Pedersen
- Steno Diabetes Center Odense, Odense University Hospital, DK-5000 Odense C, Denmark
| | - Rikke Kruse
- Department of Clinical Research & Department of Molecular Medicine, University of Southern Denmark, DK-5230 Odense M, Denmark
- Steno Diabetes Center Odense, Odense University Hospital, DK-5000 Odense C, Denmark
| | - Aase Handberg
- Department of Clinical Biochemistry, Aalborg University Hospital, North Denmark Region, DK-9000 Aalborg, Denmark
- Department of Clinical Medicine, Aalborg University, DK-9000 Aalborg, Denmark
| | - Jørgen F P Wojtaszewski
- The August Krogh Section for Molecular Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - Kurt Højlund
- Department of Clinical Research & Department of Molecular Medicine, University of Southern Denmark, DK-5230 Odense M, Denmark
- Steno Diabetes Center Odense, Odense University Hospital, DK-5000 Odense C, Denmark
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Tran M, Gilling S, Wu J, Wang L, Shin DJ. miR-141/200c contributes to ethanol-mediated hepatic glycogen metabolism. Mol Metab 2024; 84:101942. [PMID: 38642890 PMCID: PMC11060962 DOI: 10.1016/j.molmet.2024.101942] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2024] [Accepted: 04/15/2024] [Indexed: 04/22/2024] Open
Abstract
OBJECTIVE Hepatic glucose metabolism is profoundly perturbed by excessive alcohol intake. miR-141/200c expression is significantly induced by chronic ethanol feeding. This study aimed at identifying the role of miR-141/200c in glucose homeostasis during chronic ethanol exposure. METHODS WT and miR-141/200c KO mice were fed a control or an ethanol diet for 30 days, followed by a single binge of maltose dextrin or ethanol, respectively. Untargeted metabolomics analysis of hepatic primary metabolites was performed along with analyses for liver histology, gene expression, intracellular signaling pathways, and physiological relevance. Primary hepatocytes were used for mechanistic studies. RESULTS miR-141/200c deficiency rewires hepatic glucose metabolism during chronic ethanol feeding, increasing the abundance of glucose intermediates including G6P, an allosteric activator for GS. miR-141/200c deficiency replenished glycogen depletion during chronic ethanol feeding accompanied by reduced GS phosphorylation in parallel with increased expression of PP1 glycogen targeting subunits. Moreover, miR-141/200c deficiency prevented ethanol-mediated increases in AMPK and CaMKK2 activity. Ethanol treatment reduced glycogen content in WT-hepatocytes, which was reversed by dorsomorphin, a selective AMPK inhibitor, while KO-hepatocytes displayed higher glycogen content than WT-hepatocytes in response to ethanol treatment. Furthermore, treatment of hepatocytes with A23187, a calcium ionophore activating CaMKK2, lowered glycogen content in WT-hepatocytes. Notably, the suppressive effect of A23187 on glycogen deposition was reversed by dorsomorphin, demonstrating that the glycogen depletion by A23187 is mediated by AMPK. KO-hepatocytes exhibited higher glycogen content than WT-hepatocytes in response to A23187. Finally, miR-141/200c deficiency led to improved glucose tolerance and insulin sensitivity during chronic ethanol feeding. CONCLUSIONS miR-141/200c deficiency replenishes ethanol-mediated hepatic glycogen depletion through the regulation of GS activity and calcium signaling coupled with the AMPK pathway, improving glucose homeostasis and insulin sensitivity. These results underscore miR-141/200c as a potential therapeutic target for the management of alcohol intoxication.
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Affiliation(s)
- Melanie Tran
- Department of Physiology and Neurobiology, University of Connecticut, 75 N. Eagleville Rd, Storrs, CT 06269, USA
| | - Shaynian Gilling
- Department of Physiology and Neurobiology, University of Connecticut, 75 N. Eagleville Rd, Storrs, CT 06269, USA
| | - Jianguo Wu
- Department of Physiology and Neurobiology, University of Connecticut, 75 N. Eagleville Rd, Storrs, CT 06269, USA
| | - Li Wang
- Department of Internal Medicine, Section of Digestive Diseases, Yale University, 333 Cedar St, New Haven, CT 06510, USA
| | - Dong-Ju Shin
- Department of Physiology and Neurobiology, University of Connecticut, 75 N. Eagleville Rd, Storrs, CT 06269, USA.
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Wang GL, Yuan HJ, Kong QQ, Zhang J, Han X, Gong S, Xu MT, He N, Luo MJ, Tan JH. High glucose exposure of preimplantation embryos causes glucose intolerance and insulin resistance in F1 and F2 male offspring. Biochim Biophys Acta Mol Basis Dis 2024; 1870:166921. [PMID: 37879502 DOI: 10.1016/j.bbadis.2023.166921] [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: 09/10/2023] [Revised: 10/10/2023] [Accepted: 10/18/2023] [Indexed: 10/27/2023]
Abstract
BACKGROUND Although studies suggest that maternal high glucose (HG) increases offspring susceptibility to type 2 diabetes mellitus (T2DM), the underlying mechanisms are largely unclear. We studied whether glucose levels in oviducts are elevated when pregestational diabetic females get pregnant and whether the oviductal HG (OVHG) would act directly on embryos to increase offspring's T2DM susceptibility. METHODS We established an in vivo model of OVHG by injecting female mice with streptozotocin (STZ) during the preimplantation period and an in vitro model of embryo culture with HG (ECHG) by culturing preimplantation embryos with HG, before examining glucose tolerance and insulin resistance (IR) in F1 and F2 offspring. FINDINGS Injection of female mice with STZ induced a lasting significant glucose elevation in blood and oviduct fluid during the preimplantation period. The glucose tolerance test showed that both the STZ-induced OVHG and the ECHG caused glucose intolerance in F1 male and F1-sired F2 male offspring but had no effect on female offspring. Insulin tolerance test and the analysis for IR-related gene expression and glycogen contents in liver and muscle revealed significant IR in these male offspring. INTERPRETATION This study provided evidence that HG can act directly on preimplantation embryos to increase offspring's T2DM susceptibility suggesting that the preimplantation period is a critical stage for transmission of mother's diabetes to offspring. FUND: This study was supported by grants from the China National Natural Science Foundation (Nos. 31772599, 32072738, 31702114, and 31902160), and the Natural Science Foundation of Shandong Province (Nos. ZR2022MC036, ZR2017BC025 and ZR2020QC102).
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Affiliation(s)
- Guo-Liang Wang
- College of Animal Science and Veterinary Medicine, Shandong Agricultural University, Tai'an City 271018, PR China
| | - Hong-Jie Yuan
- College of Animal Science and Veterinary Medicine, Shandong Agricultural University, Tai'an City 271018, PR China
| | - Qiao-Qiao Kong
- College of Animal Science and Veterinary Medicine, Shandong Agricultural University, Tai'an City 271018, PR China
| | - Jie Zhang
- College of Animal Science and Veterinary Medicine, Shandong Agricultural University, Tai'an City 271018, PR China
| | - Xiao Han
- College of Animal Science and Veterinary Medicine, Shandong Agricultural University, Tai'an City 271018, PR China
| | - Shuai Gong
- College of Animal Science and Veterinary Medicine, Shandong Agricultural University, Tai'an City 271018, PR China
| | - Ming-Tao Xu
- College of Animal Science and Veterinary Medicine, Shandong Agricultural University, Tai'an City 271018, PR China
| | - Nan He
- College of Animal Science and Veterinary Medicine, Shandong Agricultural University, Tai'an City 271018, PR China
| | - Ming-Jiu Luo
- College of Animal Science and Veterinary Medicine, Shandong Agricultural University, Tai'an City 271018, PR China
| | - Jing-He Tan
- College of Animal Science and Veterinary Medicine, Shandong Agricultural University, Tai'an City 271018, PR China.
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Møller LLV, Ali MS, Davey J, Raun SH, Andersen NR, Long JZ, Qian H, Jeppesen JF, Henriquez-Olguin C, Frank E, Jensen TE, Højlund K, Wojtaszewski JFP, Nielsen J, Chiu TT, Jedrychowski MP, Gregorevic P, Klip A, Richter EA, Sylow L. The Rho guanine dissociation inhibitor α inhibits skeletal muscle Rac1 activity and insulin action. Proc Natl Acad Sci U S A 2023; 120:e2211041120. [PMID: 37364105 PMCID: PMC10318982 DOI: 10.1073/pnas.2211041120] [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: 07/11/2022] [Accepted: 05/22/2023] [Indexed: 06/28/2023] Open
Abstract
The molecular events governing skeletal muscle glucose uptake have pharmacological potential for managing insulin resistance in conditions such as obesity, diabetes, and cancer. With no current pharmacological treatments to target skeletal muscle insulin sensitivity, there is an unmet need to identify the molecular mechanisms that control insulin sensitivity in skeletal muscle. Here, the Rho guanine dissociation inhibitor α (RhoGDIα) is identified as a point of control in the regulation of insulin sensitivity. In skeletal muscle cells, RhoGDIα interacted with, and thereby inhibited, the Rho GTPase Rac1. In response to insulin, RhoGDIα was phosphorylated at S101 and Rac1 dissociated from RhoGDIα to facilitate skeletal muscle GLUT4 translocation. Accordingly, siRNA-mediated RhoGDIα depletion increased Rac1 activity and elevated GLUT4 translocation. Consistent with RhoGDIα's inhibitory effect, rAAV-mediated RhoGDIα overexpression in mouse muscle decreased insulin-stimulated glucose uptake and was detrimental to whole-body glucose tolerance. Aligning with RhoGDIα's negative role in insulin sensitivity, RhoGDIα protein content was elevated in skeletal muscle from insulin-resistant patients with type 2 diabetes. These data identify RhoGDIα as a clinically relevant controller of skeletal muscle insulin sensitivity and whole-body glucose homeostasis, mechanistically by modulating Rac1 activity.
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Affiliation(s)
- Lisbeth L. V. Møller
- Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, 2200Copenhagen N, Denmark
- Department of Biomedical Sciences, Faculty of Medical and Health Sciences, University of Copenhagen, 2200Copenhagen N, Denmark
| | - Mona S. Ali
- Department of Biomedical Sciences, Faculty of Medical and Health Sciences, University of Copenhagen, 2200Copenhagen N, Denmark
| | - Jonathan Davey
- The Centre for Muscle Research, Department of Physiology, The University of Melbourne, Parkville, VIC3010, Australia
| | - Steffen H. Raun
- Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, 2200Copenhagen N, Denmark
- Department of Biomedical Sciences, Faculty of Medical and Health Sciences, University of Copenhagen, 2200Copenhagen N, Denmark
| | - Nicoline R. Andersen
- Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, 2200Copenhagen N, Denmark
| | - Jonathan Z. Long
- Department of Pathology, Stanford University School of Medicine and Stanford, Stanford University, Stanford, CA94305
| | - Hongwei Qian
- The Centre for Muscle Research, Department of Physiology, The University of Melbourne, Parkville, VIC3010, Australia
| | - Jacob F. Jeppesen
- Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, 2200Copenhagen N, Denmark
| | - Carlos Henriquez-Olguin
- Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, 2200Copenhagen N, Denmark
- Exercise Science Laboratory, Faculty of Medicine, Universidad Finis Terrae, 7501015Santiago, Chile
| | - Emma Frank
- Department of Biomedical Sciences, Faculty of Medical and Health Sciences, University of Copenhagen, 2200Copenhagen N, Denmark
| | - Thomas E. Jensen
- Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, 2200Copenhagen N, Denmark
| | - Kurt Højlund
- Steno Diabetes Center Odense, Odense University Hospital, 5000Odense C, Denmark
- Department of Clinical Research, University of Southern Denmark, 5000Odense C, Denmark
- Department of Molecular Medicine, University of Southern Denmark, 5000Odense C, Denmark
| | - Jørgen F. P. Wojtaszewski
- Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, 2200Copenhagen N, Denmark
| | - Joachim Nielsen
- Department of Sports Science and Clinical Biomechanics, University of Southern Denmark, 5230Odense M, Denmark
| | - Tim T. Chiu
- Cell Biology Program, The Hospital for Sick Children, Toronto, ONM5G 0A4, Canada
- Department of Biochemistry, University of Toronto, Toronto, ONM5S 1A1, Canada
- Department of Physiology, University of Toronto, Toronto, ONM5S 1A1, Canada
- Department of Paediatrics, University of Toronto, Toronto, ONM5S 1A1, Canada
| | - Mark P. Jedrychowski
- Department of Cell Biology, Harvard Medical School, Boston, MA02115
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA02215
| | - Paul Gregorevic
- The Centre for Muscle Research, Department of Physiology, The University of Melbourne, Parkville, VIC3010, Australia
| | - Amira Klip
- Cell Biology Program, The Hospital for Sick Children, Toronto, ONM5G 0A4, Canada
- Department of Biochemistry, University of Toronto, Toronto, ONM5S 1A1, Canada
- Department of Physiology, University of Toronto, Toronto, ONM5S 1A1, Canada
- Department of Paediatrics, University of Toronto, Toronto, ONM5S 1A1, Canada
| | - Erik A. Richter
- Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, 2200Copenhagen N, Denmark
| | - Lykke Sylow
- Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, 2200Copenhagen N, Denmark
- Department of Biomedical Sciences, Faculty of Medical and Health Sciences, University of Copenhagen, 2200Copenhagen N, Denmark
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6
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Høgild ML, Hjelholt AJ, Hansen J, Pedersen SB, Møller N, Wojtaszewski JFP, Johannsen M, Jessen N, Jørgensen JOL. Ketone Body Infusion Abrogates Growth Hormone-Induced Lipolysis and Insulin Resistance. J Clin Endocrinol Metab 2023; 108:653-664. [PMID: 36240323 DOI: 10.1210/clinem/dgac595] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Revised: 10/10/2022] [Indexed: 11/19/2022]
Abstract
CONTEXT Exogenous ketone body administration lowers circulating glucose levels but the underlying mechanisms are uncertain. OBJECTIVE We tested the hypothesis that administration of the ketone body β-hydroxybutyrate (βOHB) acutely increases insulin sensitivity via feedback suppression of circulating free fatty acid (FFA) levels. METHODS In a randomized, single-blinded crossover design, 8 healthy men were studied twice with a growth hormone (GH) infusion to induce lipolysis in combination with infusion of either βOHB or saline. Each study day comprised a basal period and a hyperinsulinemic-euglycemic clamp combined with a glucose tracer and adipose tissue and skeletal muscle biopsies. RESULTS βOHB administration profoundly suppressed FFA levels concomitantly with a significant increase in glucose disposal and energy expenditure. This was accompanied by a many-fold increase in skeletal muscle content of both βOHB and its derivative acetoacetate. CONCLUSION Our data unravel an insulin-sensitizing effect of βOHB, which we suggest is mediated by concomitant suppression of lipolysis.
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Affiliation(s)
- Morten Lyng Høgild
- Medical Research Laboratory, Department of Clinical Medicine, Endocrinology and Internal Medicine, Aarhus University Hospital, Aarhus N, Region Midtjylland 8200, Denmark
| | - Astrid Johannesson Hjelholt
- Medical Research Laboratory, Department of Clinical Medicine, Endocrinology and Internal Medicine, Aarhus University Hospital, Aarhus N, Region Midtjylland 8200, Denmark
- Department of Clinical Pharmacology, Aarhus University Hospital, Aarhus N, Region Midtjylland 8200, Denmark
| | - Jakob Hansen
- Department of Forensic Medicine, Aarhus University, Aarhus N 8200, Denmark
| | - Steen Bønløkke Pedersen
- Steno Diabetes Centre Aarhus, Aarhus University Hospital, Aarhus N, Region Midtjylland 8200, Denmark
| | - Niels Møller
- Medical Research Laboratory, Department of Clinical Medicine, Endocrinology and Internal Medicine, Aarhus University Hospital, Aarhus N, Region Midtjylland 8200, Denmark
- Department of Forensic Medicine, Aarhus University, Aarhus N 8200, Denmark
| | - Jørgen F P Wojtaszewski
- August Krogh Section for Molecular Physiology, University of Copenhagen, Copenhagen 2100, Denmark
| | - Mogens Johannsen
- Department of Forensic Medicine, Aarhus University, Aarhus N 8200, Denmark
| | - Niels Jessen
- Department of Clinical Pharmacology, Aarhus University Hospital, Aarhus N, Region Midtjylland 8200, Denmark
- Steno Diabetes Centre Aarhus, Aarhus University Hospital, Aarhus N, Region Midtjylland 8200, Denmark
- Department of Biomedicine, Aarhus University, Aarhus 8000, Denmark
| | - Jens Otto Lunde Jørgensen
- Medical Research Laboratory, Department of Clinical Medicine, Endocrinology and Internal Medicine, Aarhus University Hospital, Aarhus N, Region Midtjylland 8200, Denmark
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de Almeida ME, Nielsen J, Petersen MH, Wentorf EK, Pedersen NB, Jensen K, Højlund K, Ørtenblad N. Altered intramuscular network of lipid droplets and mitochondria in type 2 diabetes. Am J Physiol Cell Physiol 2023; 324:C39-C57. [PMID: 36409174 DOI: 10.1152/ajpcell.00470.2022] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Excessive storage of lipid droplets (LDs) in skeletal muscles is a hallmark of type 2 diabetes. However, LD morphology displays a high degree of subcellular heterogeneity and varies between single muscle fibers, which impedes the current understanding of lipid-induced insulin resistance. Using quantitative transmission electron microscopy (TEM), we conducted a comprehensive single-fiber morphological analysis to investigate the intramuscular network of LDs and mitochondria, and the effects of 8 wk of high-intensity interval training (HIIT) targeting major muscle groups, in patients with type 2 diabetes and nondiabetic obese and lean controls. We found that excessive storage of intramuscular lipids in patients with type 2 diabetes was exclusively explained by extremely large LDs situated in distinct muscle fibers with a location-specific deficiency in subsarcolemmal mitochondria. After HIIT, this intramuscular deficiency was improved by a remodeling of LD size and subcellular distribution and mitochondrial content. Analysis of LD morphology further revealed that individual organelles were better described as ellipsoids than spheres. Moreover, physical contact between LD and mitochondrial membranes indicated a dysfunctional interplay between organelles in the diabetic state. Taken together, type 2 diabetes should be recognized as a metabolic disease with high cellular heterogeneity in intramuscular lipid storage, underlining the relevance of single-cell technologies in clinical research. Furthermore, HIIT changed intramuscular LD storage toward nondiabetic characteristics.
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Affiliation(s)
- Martin Eisemann de Almeida
- Department of Sports Science and Clinical Biomechanics, Faculty of Health Sciences, University of Southern Denmark, Odense, Denmark.,Steno Diabetes Center Odense, Odense University Hospital, Odense, Denmark
| | - Joachim Nielsen
- Department of Sports Science and Clinical Biomechanics, Faculty of Health Sciences, University of Southern Denmark, Odense, Denmark
| | - Maria Houborg Petersen
- Steno Diabetes Center Odense, Odense University Hospital, Odense, Denmark.,Department of Clinical Research, Faculty of Health Sciences, University of Southern Denmark, Odense, Denmark
| | - Emil Kleis Wentorf
- Department of Sports Science and Clinical Biomechanics, Faculty of Health Sciences, University of Southern Denmark, Odense, Denmark
| | - Niklas Bigum Pedersen
- Department of Sports Science and Clinical Biomechanics, Faculty of Health Sciences, University of Southern Denmark, Odense, Denmark
| | - Kurt Jensen
- Department of Sports Science and Clinical Biomechanics, Faculty of Health Sciences, University of Southern Denmark, Odense, Denmark
| | - Kurt Højlund
- Steno Diabetes Center Odense, Odense University Hospital, Odense, Denmark
| | - Niels Ørtenblad
- Department of Sports Science and Clinical Biomechanics, Faculty of Health Sciences, University of Southern Denmark, Odense, Denmark
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Chakraborty S, Devi Rajeswari V. Biomedical aspects of beta-glucan on glucose metabolism and its role on primary gene PIK3R1. J Funct Foods 2022. [DOI: 10.1016/j.jff.2022.105296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Dumolt J, Powell TL, Jansson T, Rosario FJ. Normalization of maternal adiponectin in obese pregnant mice prevents programming of impaired glucose metabolism in adult offspring. FASEB J 2022; 36:e22383. [PMID: 35670755 DOI: 10.1096/fj.202200326r] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 05/16/2022] [Accepted: 05/19/2022] [Indexed: 11/11/2022]
Abstract
Infants born to obese mothers have a greater risk for childhood obesity and insulin resistance. However, the underlying biological mechanism remains elusive, which constitutes a significant roadblock for developing specific prevention strategies. Maternal adiponectin levels are lower in obese pregnant women, which is linked with increased placental nutrient transport and fetal overgrowth. We have previously reported that adiponectin supplementation to obese dams during the last four days of pregnancy prevented the development of obesity, glucose intolerance, muscle insulin resistance, and fatty liver in three months old offspring. In the present study, we tested the hypothesis that 6-9-month-old offspring of obese dams show glucose intolerance associated with muscle insulin resistance and mitochondrial dysfunction and that normalization of maternal adiponectin in obese pregnant mice prevents the development of this phenotype in the offspring. Male and female offspring of obese mice exhibited in vivo glucose intolerance and insulin resistance at 6 and 9 months of age. In gastrocnemius muscles ex vivo, male and female offspring of obese dams showed reduced phosphorylation of insulin receptor substrate 1Tyr-608 , AktThr-308 , and decreased Glut4 plasma membrane translocation upon insulin stimulation. These metabolic abnormalities in offspring born to obese mice were largely prevented by normalization of maternal adiponectin levels in late pregnancy. We provide evidence that low circulating maternal adiponectin is a critical mechanistic link between maternal obesity and the development of metabolic disease in offspring. Strategies aimed at improving maternal adiponectin levels may prevent long-term metabolic dysfunction in offspring of obese mothers.
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Affiliation(s)
- Jerad Dumolt
- Division of Reproductive Sciences, Department of OB/GYN, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Theresa L Powell
- Division of Reproductive Sciences, Department of OB/GYN, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA.,Section of Neonatology, Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Thomas Jansson
- Division of Reproductive Sciences, Department of OB/GYN, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Fredrick J Rosario
- Division of Reproductive Sciences, Department of OB/GYN, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
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10
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Larsen JK, Larsen MR, Birk JB, Steenberg DE, Hingst JR, Højlund K, Chadt A, Al-Hasani H, Deshmukh AS, Wojtaszewski JF, Kjøbsted R. Illumination of the Endogenous Insulin-Regulated TBC1D4 Interactome in Human Skeletal Muscle. Diabetes 2022; 71:906-920. [PMID: 35192682 PMCID: PMC9074744 DOI: 10.2337/db21-0855] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Accepted: 02/15/2022] [Indexed: 11/13/2022]
Abstract
Insulin-stimulated muscle glucose uptake is a key process in glycemic control. This process depends on the redistribution of glucose transporters to the surface membrane, a process that involves regulatory proteins such as TBC1D1 and TBC1D4. Accordingly, a TBC1D4 loss-of-function mutation in human skeletal muscle is associated with an increased risk of type 2 diabetes, and observations from carriers of a TBC1D1 variant associate this protein to a severe obesity phenotype. Here, we identified interactors of the endogenous TBC1D4 protein in human skeletal muscle by an unbiased proteomics approach. We detected 76 proteins as candidate TBC1D4 interactors. The binding of 12 of these interactors was regulated by insulin, including proteins known to be involved in glucose metabolism (e.g., 14-3-3 proteins and α-actinin-4 [ACTN4]). TBC1D1 also coprecipitated with TBC1D4 and vice versa in both human and mouse skeletal muscle. This interaction was not regulated by insulin or exercise in young, healthy, lean individuals. Similarly, the exercise- and insulin-regulated phosphorylation of the TBC1D1-TBC1D4 complex was intact. In contrast, we observed an altered interaction as well as compromised insulin-stimulated phosphoregulation of the TBC1D1-TBC1D4 complex in muscle of obese individuals with type 2 diabetes. Altogether, we provide a repository of TBC1D4 interactors in human and mouse skeletal muscle that serve as potential regulators of TBC1D4 function and, thus, insulin-stimulated glucose uptake in human skeletal muscle.
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Affiliation(s)
- Jeppe K. Larsen
- August Krogh Section for Molecular Physiology, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
- Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, Denmark
| | - Magnus R. Larsen
- August Krogh Section for Molecular Physiology, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Jesper B. Birk
- August Krogh Section for Molecular Physiology, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Dorte E. Steenberg
- August Krogh Section for Molecular Physiology, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Janne R. Hingst
- August Krogh Section for Molecular Physiology, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Kurt Højlund
- Steno Diabetes Center Odense, Odense University Hospital, Odense, Denmark
- Department of Clinical Research, University of Southern Denmark, Odense, Denmark
| | - Alexandra Chadt
- German Diabetes Center, Leibniz Center for Diabetes Research at the Heinrich Heine University Düsseldorf, Düsseldorf, Germany
- German Center for Diabetes Research (DZD), München-Neuherberg, Germany
| | - Hadi Al-Hasani
- German Diabetes Center, Leibniz Center for Diabetes Research at the Heinrich Heine University Düsseldorf, Düsseldorf, Germany
- German Center for Diabetes Research (DZD), München-Neuherberg, Germany
| | - Atul S. Deshmukh
- Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, Denmark
| | - Jørgen F.P. Wojtaszewski
- August Krogh Section for Molecular Physiology, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
- Corresponding authors: Rasmus Kjøbsted, , and Jørgen F.P. Wojtaszewski,
| | - Rasmus Kjøbsted
- August Krogh Section for Molecular Physiology, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
- Corresponding authors: Rasmus Kjøbsted, , and Jørgen F.P. Wojtaszewski,
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11
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Xie X, Shu R, Yu C, Fu Z, Li Z. Mammalian AKT, the Emerging Roles on Mitochondrial Function in Diseases. Aging Dis 2022; 13:157-174. [PMID: 35111368 PMCID: PMC8782557 DOI: 10.14336/ad.2021.0729] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Accepted: 07/29/2021] [Indexed: 01/21/2023] Open
Abstract
Mitochondrial dysfunction may play a crucial role in various diseases due to its roles in the regulation of energy production and cellular metabolism. Serine/threonine kinase (AKT) is a highly recognized antioxidant, immunomodulatory, anti-proliferation, and endocrine modulatory molecule. Interestingly, increasing studies have revealed that AKT can modulate mitochondria-mediated apoptosis, redox states, dynamic balance, autophagy, and metabolism. AKT thus plays multifaceted roles in mitochondrial function and is involved in the modulation of mitochondria-related diseases. This paper reviews the protective effects of AKT and its potential mechanisms of action in relation to mitochondrial function in various diseases.
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Affiliation(s)
- Xiaoxian Xie
- 1College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, China
| | - Ruonan Shu
- 1College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, China
| | - Chunan Yu
- 1College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, China
| | - Zhengwei Fu
- 1College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, China
| | - Zezhi Li
- 2Department of Psychiatry, The Affiliated Brain Hospital of Guangzhou Medical University, Guangzhou, China
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12
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Ham JR, Lee HI, Lee Y, Lee HJ, Kim HY, Son YJ, Lee MK, Lee MJ. Dual beneficial effects of naked barley “Betaone” extract on high-fat diet/streptozotocin-induced hyperglycemia and hepatosteatosis in mice. J Cereal Sci 2021. [DOI: 10.1016/j.jcs.2021.103358] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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13
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Battista F, Belligoli A, Neunhaeuserer D, Gasperetti A, Bettini S, Compagnin C, Marchese R, Quinto G, Bergamin M, Vettor R, Busetto L, Ermolao A. Metabolic Response to Submaximal and Maximal Exercise in People with Severe Obesity, Prediabetes, and Diabetes. Obes Facts 2021; 14:415-424. [PMID: 34344002 PMCID: PMC8406246 DOI: 10.1159/000517589] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Accepted: 05/31/2021] [Indexed: 11/19/2022] Open
Abstract
INTRODUCTION Metabolic adaptations to maximal physical exercise in people with obesity (PwO) are scarcely described. This cross-sectional study evaluates the metabolic response to exercise via the respiratory exchange ratio (RER) in PwO and different degrees of glycemic control. METHODS Eighty-five PwO (body mass index 46.0 [39.0-54.0] kg/m2), that is, 32 normoglycemic (Ob-N), 25 prediabetic (Ob-preDM), and 28 diabetic (Ob-T2DM) subjects and 18 healthy subjects performed an incremental, maximal cardiopulmonary exercise test. The RER was measured at rest (RERrest) and at peak exercise (RERpeak). RESULTS RERpeak was significantly higher in healthy subjects than that in PwO. Among those, RERpeak was significantly higher in Ob-N than that in Ob-preDM and Ob-T2DM (1.20 [1.15-1.27] vs. 1.18 [1.10-1.22] p = 0.04 and vs. 1.14 [1.10-1.18] p < 0.001, respectively). Accordingly, ΔRER (RERpeak-RERrest) was lower in Ob-preDM and Ob-T2DM than that in Ob-N (0.32 [0.26-0.39] p = 0.04 and 0.29 [0.24-0.36] p < 0.001 vs. 0.38 [0.32-0.43], respectively), while no significant difference was found in ΔRER between Ob-preDM and Ob-T2DM and not even between Ob-N and healthy subjects. Moreover, ΔRER in PwO correlated with glucose area under curve (p = 0.002). CONCLUSIONS PwO demonstrate restricted metabolic response during maximal exercise. Particularly, those with prediabetes already show metabolic inflexibility during exercise, similarly to those with type 2 diabetes. These findings also suggest a potential role of cardiopulmonary exercise testing in detecting early metabolic alterations in PwO.
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Affiliation(s)
- Francesca Battista
- Sports and Exercise Medicine Division, Department of Medicine, University of Padova, Padova, Italy,
- Center for the Study and the Integrated Treatment of Obesity, Padova Hospital, Padova, Italy,
| | - Anna Belligoli
- Center for the Study and the Integrated Treatment of Obesity, Padova Hospital, Padova, Italy
- Department of Medicine, Internal Medicine 3, University Hospital of Padova, Padova, Italy
| | - Daniel Neunhaeuserer
- Sports and Exercise Medicine Division, Department of Medicine, University of Padova, Padova, Italy
- Center for the Study and the Integrated Treatment of Obesity, Padova Hospital, Padova, Italy
| | - Andrea Gasperetti
- Sports and Exercise Medicine Division, Department of Medicine, University of Padova, Padova, Italy
- Center for the Study and the Integrated Treatment of Obesity, Padova Hospital, Padova, Italy
| | - Silvia Bettini
- Center for the Study and the Integrated Treatment of Obesity, Padova Hospital, Padova, Italy
- Department of Medicine, Internal Medicine 3, University Hospital of Padova, Padova, Italy
| | - Chiara Compagnin
- Center for the Study and the Integrated Treatment of Obesity, Padova Hospital, Padova, Italy
- Department of Medicine, Internal Medicine 3, University Hospital of Padova, Padova, Italy
| | - Riccardo Marchese
- Center for the Study and the Integrated Treatment of Obesity, Padova Hospital, Padova, Italy
- Department of Medicine, Internal Medicine 3, University Hospital of Padova, Padova, Italy
| | - Giulia Quinto
- Sports and Exercise Medicine Division, Department of Medicine, University of Padova, Padova, Italy
- Center for the Study and the Integrated Treatment of Obesity, Padova Hospital, Padova, Italy
| | - Marco Bergamin
- Sports and Exercise Medicine Division, Department of Medicine, University of Padova, Padova, Italy
- Center for the Study and the Integrated Treatment of Obesity, Padova Hospital, Padova, Italy
| | - Roberto Vettor
- Center for the Study and the Integrated Treatment of Obesity, Padova Hospital, Padova, Italy
- Department of Medicine, Internal Medicine 3, University Hospital of Padova, Padova, Italy
| | - Luca Busetto
- Center for the Study and the Integrated Treatment of Obesity, Padova Hospital, Padova, Italy
- Department of Medicine, Internal Medicine 3, University Hospital of Padova, Padova, Italy
| | - Andrea Ermolao
- Sports and Exercise Medicine Division, Department of Medicine, University of Padova, Padova, Italy
- Center for the Study and the Integrated Treatment of Obesity, Padova Hospital, Padova, Italy
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14
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Kalita B, Bano S, Vavachan VM, Taunk K, Seshadri V, Rapole S. Application of mass spectrometry based proteomics to understand diabetes: A special focus on interactomics. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2020; 1868:140469. [DOI: 10.1016/j.bbapap.2020.140469] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 05/07/2020] [Accepted: 06/04/2020] [Indexed: 12/11/2022]
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15
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Vadlakonda L, Indracanti M, Kalangi SK, Gayatri BM, Naidu NG, Reddy ABM. The Role of Pi, Glutamine and the Essential Amino Acids in Modulating the Metabolism in Diabetes and Cancer. J Diabetes Metab Disord 2020; 19:1731-1775. [PMID: 33520860 DOI: 10.1007/s40200-020-00566-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Accepted: 06/04/2020] [Indexed: 02/07/2023]
Abstract
Purpose Re-examine the current metabolic models. Methods Review of literature and gene networks. Results Insulin activates Pi uptake, glutamine metabolism to stabilise lipid membranes. Tissue turnover maintains the metabolic health. Current model of intermediary metabolism (IM) suggests glucose is the source of energy, and anaplerotic entry of fatty acids and amino acids into mitochondria increases the oxidative capacity of the TCA cycle to produce the energy (ATP). The reduced cofactors, NADH and FADH2, have different roles in regulating the oxidation of nutrients, membrane potentials and biosynthesis. Trans-hydrogenation of NADH to NADPH activates the biosynthesis. FADH2 sustains the membrane potential during the cell transformations. Glycolytic enzymes assume the non-canonical moonlighting functions, enter the nucleus to remodel the genetic programmes to affect the tissue turnover for efficient use of nutrients. Glycosylation of the CD98 (4F2HC) stabilises the nutrient transporters and regulates the entry of cysteine, glutamine and BCAA into the cells. A reciprocal relationship between the leucine and glutamine entry into cells regulates the cholesterol and fatty acid synthesis and homeostasis in cells. Insulin promotes the Pi transport from the blood to tissues, activates the mitochondrial respiratory activity, and glutamine metabolism, which activates the synthesis of cholesterol and the de novo fatty acids for reorganising and stabilising the lipid membranes for nutrient transport and signal transduction in response to fluctuations in the microenvironmental cues. Fatty acids provide the lipid metabolites, activate the second messengers and protein kinases. Insulin resistance suppresses the lipid raft formation and the mitotic slippage activates the fibrosis and slow death pathways.
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Affiliation(s)
| | - Meera Indracanti
- Institute of Biotechnology, University of Gondar, Gondar, Ethiopia
| | - Suresh K Kalangi
- Amity Stem Cell Institute, Amity University Haryana, Amity Education Valley Pachgaon, Manesar, Gurugram, HR 122413 India
| | - B Meher Gayatri
- Department of Animal Biology, School of Life Sciences, University of Hyderabad, Hyderabad, 500046 India
| | - Navya G Naidu
- Department of Animal Biology, School of Life Sciences, University of Hyderabad, Hyderabad, 500046 India
| | - Aramati B M Reddy
- Department of Animal Biology, School of Life Sciences, University of Hyderabad, Hyderabad, 500046 India
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16
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Dahl MA, Areta JL, Jeppesen PB, Birk JB, Johansen EI, Ingemann-Hansen T, Hansen M, Skålhegg BS, Ivy JL, Wojtaszewski JFP, Overgaard K, Jensen J. Coingestion of protein and carbohydrate in the early recovery phase, compared with carbohydrate only, improves endurance performance despite similar glycogen degradation and AMPK phosphorylation. J Appl Physiol (1985) 2020; 129:297-310. [DOI: 10.1152/japplphysiol.00817.2019] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Endurance athletes competing consecutive days need optimal dietary intake during the recovery period. We report that coingestion of protein and carbohydrate soon after exhaustive exercise, compared with carbohydrate only, resulted in better performance the following day. The better performance after coingestion of protein and carbohydrate was not associated with a higher rate of glycogen synthesis or activation of anabolic signaling compared with carbohydrate only. Importantly, nitrogen balance was positive after coingestion of protein and carbohydrate, which was not the case after intake of carbohydrate only, suggesting that protein synthesis contributes to the better performance the following day.
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Affiliation(s)
- Marius A. Dahl
- Department of Physical Performance, Norwegian School of Sports Sciences, Oslo, Norway
| | - José Lisandro Areta
- Department of Physical Performance, Norwegian School of Sports Sciences, Oslo, Norway
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, United Kingdom
| | | | - Jesper Bratz Birk
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Egil I. Johansen
- Department of Physical Performance, Norwegian School of Sports Sciences, Oslo, Norway
| | | | - Mette Hansen
- Department of Public Health, Aarhus University, Aarhus C, Denmark
| | - Bjørn Steen Skålhegg
- Department of Nutrition, Division for Molecular Nutrition, University of Oslo, Oslo, Norway
| | - John L. Ivy
- Department of Kinesiology and Health Education, University of Texas at Austin, Austin, Texas
| | - Jørgen F. P. Wojtaszewski
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | | | - Jørgen Jensen
- Department of Physical Performance, Norwegian School of Sports Sciences, Oslo, Norway
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
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17
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Inducible deletion of skeletal muscle AMPKα reveals that AMPK is required for nucleotide balance but dispensable for muscle glucose uptake and fat oxidation during exercise. Mol Metab 2020; 40:101028. [PMID: 32504885 PMCID: PMC7356270 DOI: 10.1016/j.molmet.2020.101028] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 05/25/2020] [Accepted: 05/26/2020] [Indexed: 02/05/2023] Open
Abstract
Objective Evidence for AMP-activated protein kinase (AMPK)-mediated regulation of skeletal muscle metabolism during exercise is mainly based on transgenic mouse models with chronic (lifelong) disruption of AMPK function. Findings based on such models are potentially biased by secondary effects related to a chronic lack of AMPK function. To study the direct effect(s) of AMPK on muscle metabolism during exercise, we generated a new mouse model with inducible muscle-specific deletion of AMPKα catalytic subunits in adult mice. Methods Tamoxifen-inducible and muscle-specific AMPKα1/α2 double KO mice (AMPKα imdKO) were generated by using the Cre/loxP system, with the Cre under the control of the human skeletal muscle actin (HSA) promoter. Results During treadmill running at the same relative exercise intensity, AMPKα imdKO mice showed greater depletion of muscle ATP, which was associated with accumulation of the deamination product IMP. Muscle-specific deletion of AMPKα in adult mice promptly reduced maximal running speed and muscle glycogen content and was associated with reduced expression of UGP2, a key component of the glycogen synthesis pathway. Muscle mitochondrial respiration, whole-body substrate utilization, and muscle glucose uptake and fatty acid (FA) oxidation during muscle contractile activity remained unaffected by muscle-specific deletion of AMPKα subunits in adult mice. Conclusions Inducible deletion of AMPKα subunits in adult mice reveals that AMPK is required for maintaining muscle ATP levels and nucleotide balance during exercise but is dispensable for regulating muscle glucose uptake, FA oxidation, and substrate utilization during exercise. Inducible deletion of AMPKα in adult mice disturbs nucleotide balance during exercise. Inducible deletion of AMPKα in adult mice lowers muscle glycogen content and reduces exercise capacity. Muscle mitochondrial respiration, and glucose uptake and FA oxidation during muscle contractions remain unaffected by AMPKα deletion.
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18
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Steenberg DE, Hingst JR, Birk JB, Thorup A, Kristensen JM, Sjøberg KA, Kiens B, Richter EA, Wojtaszewski JFP. A Single Bout of One-Legged Exercise to Local Exhaustion Decreases Insulin Action in Nonexercised Muscle Leading to Decreased Whole-Body Insulin Action. Diabetes 2020; 69:578-590. [PMID: 31974138 DOI: 10.2337/db19-1010] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Accepted: 01/14/2020] [Indexed: 11/13/2022]
Abstract
A single bout of exercise enhances insulin action in the exercised muscle. However, not all human studies find that this translates into increased whole-body insulin action, suggesting that insulin action in rested muscle or other organs may be decreased by exercise. To investigate this, eight healthy men underwent a euglycemic-hyperinsulinemic clamp on 2 separate days: one day with prior one-legged knee-extensor exercise to local exhaustion (∼2.5 h) and another day without exercise. Whole-body glucose disposal was ∼18% lower on the exercise day as compared with the resting day due to decreased (∼37%) insulin-stimulated glucose uptake in the nonexercised muscle. Insulin signaling at the level of Akt2 was impaired in the nonexercised muscle on the exercise day, suggesting that decreased insulin action in nonexercised muscle may reduce GLUT4 translocation in response to insulin. Thus, the effect of a single bout of exercise on whole-body insulin action depends on the balance between local effects increasing and systemic effects decreasing insulin action. Physiologically, this mechanism may serve to direct glucose into the muscles in need of glycogen replenishment. For insulin-treated patients, this complex relationship may explain the difficulties in predicting the adequate insulin dose for maintaining glucose homeostasis following physical activity.
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Affiliation(s)
- Dorte E Steenberg
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Janne R Hingst
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Jesper B Birk
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Anette Thorup
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Jonas M Kristensen
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Kim A Sjøberg
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Bente Kiens
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Erik A Richter
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Jørgen F P Wojtaszewski
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
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19
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Li Y, Ma Q, Li P, Wang J, Wang M, Fan Y, Wang T, Wang C, Wang T, Zhao B. Proteomics reveals different pathological processes of adipose tissue, liver, and skeletal muscle under insulin resistance. J Cell Physiol 2020; 235:6441-6461. [PMID: 32115712 DOI: 10.1002/jcp.29658] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Accepted: 02/12/2020] [Indexed: 12/17/2022]
Abstract
Type 2 diabetes mellitus is the most common type of diabetes, and insulin resistance (IR) is its core pathological mechanism. Proteomics is an ingenious and promising Omics technology that can comprehensively describe the global protein expression profiling of body or specific tissue, and is widely applied to the study of molecular mechanisms of diseases. In this paper, we focused on insulin target organs: adipose tissue, liver, and skeletal muscle, and analyzed the different pathological processes of IR in these three tissues based on proteomics research. By literature studies, we proposed that the main pathological processes of IR among target organs were diverse, which showed unique characteristics and focuses. We further summarized the differential proteins in target organs which were verified to be related to IR, and discussed the proteins that may play key roles in the emphasized pathological processes, aiming at discovering potentially specific differential proteins of IR, and providing new ideas for pathological mechanism research of IR.
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Affiliation(s)
- Yaqi Li
- School of Chinese Materia Medica, Beijing University of Chinese Medicine, Beijing, China
| | - Quantao Ma
- School of Chinese Materia Medica, Beijing University of Chinese Medicine, Beijing, China
| | - Pengfei Li
- School of Chinese Materia Medica, Beijing University of Chinese Medicine, Beijing, China
| | - Jingkang Wang
- School of Chinese Materia Medica, Beijing University of Chinese Medicine, Beijing, China
| | - Min Wang
- School of Chinese Materia Medica, Beijing University of Chinese Medicine, Beijing, China
| | - Yuanyuan Fan
- School of Chinese Materia Medica, Beijing University of Chinese Medicine, Beijing, China
| | - Tieshan Wang
- Beijing Research Institute of Chinese Medicine, Beijing University of Chinese Medicine, Beijing, China
| | - Chunguo Wang
- Beijing Research Institute of Chinese Medicine, Beijing University of Chinese Medicine, Beijing, China
| | - Ting Wang
- Beijing Research Institute of Chinese Medicine, Beijing University of Chinese Medicine, Beijing, China
| | - Baosheng Zhao
- Beijing Research Institute of Chinese Medicine, Beijing University of Chinese Medicine, Beijing, China
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20
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Jaiswal N, Gavin MG, Quinn WJ, Luongo TS, Gelfer RG, Baur JA, Titchenell PM. The role of skeletal muscle Akt in the regulation of muscle mass and glucose homeostasis. Mol Metab 2019; 28:1-13. [PMID: 31444134 PMCID: PMC6822261 DOI: 10.1016/j.molmet.2019.08.001] [Citation(s) in RCA: 88] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Revised: 07/29/2019] [Accepted: 08/01/2019] [Indexed: 12/15/2022] Open
Abstract
OBJECTIVE Skeletal muscle insulin signaling is a major determinant of muscle growth and glucose homeostasis. Protein kinase B/Akt plays a prominent role in mediating many of the metabolic effects of insulin. Mice and humans harboring systemic loss-of-function mutations in Akt2, the most abundant Akt isoform in metabolic tissues, are glucose intolerant and insulin resistant. Since the skeletal muscle accounts for a significant amount of postprandial glucose disposal, a popular hypothesis in the diabetes field suggests that a reduction in Akt, specifically in skeletal muscle, leads to systemic glucose intolerance and insulin resistance. Despite this common belief, the specific role of skeletal muscle Akt in muscle growth and insulin sensitivity remains undefined. METHODS We generated multiple mouse models of skeletal muscle Akt deficiency to evaluate the role of muscle Akt signaling in vivo. The effects of these genetic perturbations on muscle mass, glucose homeostasis and insulin sensitivity were assessed using both in vivo and ex vivo assays. RESULTS Surprisingly, mice lacking Akt2 alone in skeletal muscle displayed normal skeletal muscle insulin signaling, glucose tolerance, and insulin sensitivity despite a dramatic reduction in phosphorylated Akt. In contrast, deletion of both Akt isoforms (M-AktDKO) prevented downstream signaling and resulted in muscle atrophy. Despite the absence of Akt signaling, in vivo and ex vivo insulin-stimulated glucose uptake were normal in M-AktDKO mice. Similar effects on insulin sensitivity were observed in mice with prolonged deletion (4 weeks) of both skeletal muscle Akt isoforms selectively in adulthood. Conversely, short term deletion (2 weeks) of skeletal muscle specific Akt in adult muscles impaired insulin tolerance paralleling the effect observed by acute pharmacological inhibition of Akt in vitro. Mechanistically, chronic ablation of Akt induced mitochondrial dysfunction and activation of AMPK, which was required for insulin-stimulated glucose uptake in the absence of Akt. CONCLUSIONS Together, these data indicate that chronic reduction in Akt activity alone in skeletal muscle is not sufficient to induce insulin resistance or prevent glucose uptake in all conditions. Therefore, since insulin-stimulated glucose disposal in skeletal muscle is markedly impaired in insulin-resistant states, we hypothesize that alterations in signaling molecules in addition to skeletal muscle Akt are necessary to perturb glucose tolerance and insulin sensitivity in vivo.
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Affiliation(s)
- N Jaiswal
- Institute for Diabetes, Obesity, and Metabolism, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - M G Gavin
- Institute for Diabetes, Obesity, and Metabolism, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - W J Quinn
- Institute for Diabetes, Obesity, and Metabolism, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - T S Luongo
- Institute for Diabetes, Obesity, and Metabolism, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - R G Gelfer
- Institute for Diabetes, Obesity, and Metabolism, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - J A Baur
- Institute for Diabetes, Obesity, and Metabolism, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA; Department of Physiology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - P M Titchenell
- Institute for Diabetes, Obesity, and Metabolism, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA; Department of Physiology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA.
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Zhang WQ, Zhao TT, Gui DK, Gao CL, Gu JL, Gan WJ, Huang W, Xu Y, Zhou H, Chen WN, Liu ZL, Xu YH. Sodium Butyrate Improves Liver Glycogen Metabolism in Type 2 Diabetes Mellitus. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2019; 67:7694-7705. [PMID: 31250637 DOI: 10.1021/acs.jafc.9b02083] [Citation(s) in RCA: 64] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Liver plays a central role in modulating blood glucose level. Our most recent findings suggested that supplementation with microbiota metabolite sodium butyrate (NaB) could ameliorate progression of type 2 diabetes mellitus (T2DM) and decrease blood HbA1c in db/db mice. To further investigate the role of butyrate in homeostasis of blood glucose and glycogen metabolism, we carried out the present study. In db/db mice, we found significant hypertrophy and steatosis in hepatic lobules accompanied by reduced glycogen storage, and expression of GPR43 was significantly decreased by 59.38 ± 3.33%; NaB administration significantly increased NaB receptor G-protein coupled receptor 43 (GPR43) level and increased glycogen storage in both mice and HepG2 cells. Glucose transporter 2 (GLUT2) and sodium-glucose cotransporter 1 (SGLT1) on cell membrane were upregulated by NaB. The activation of intracellular signaling Protein kinase B (PKB), also known as AKT, was inhibited while glycogen synthase kinase 3 (GSK3) was activated by NaB in both in vivo and in vitro studies. The present study demonstrated that microbiota metabolite NaB possessed beneficial effects on preserving blood glucose homeostasis by promoting glycogen metabolism in liver cells, and the GPR43-AKT-GSK3 signaling pathway should contribute to this effect.
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Affiliation(s)
- Wen-Qian Zhang
- Faculty of Chinese Medicine, State Key Laboratory of Quality Research in Chinese Medicine , Macau University of Science and Technology , Avenida Wai Long , Taipa , Macao 999078 , People's Republic of China
| | - Ting-Ting Zhao
- Faculty of Chinese Medicine, State Key Laboratory of Quality Research in Chinese Medicine , Macau University of Science and Technology , Avenida Wai Long , Taipa , Macao 999078 , People's Republic of China
| | - Ding-Kun Gui
- Department of Nephrology , Shanghai Jiaotong University Affiliated Sixth People's Hospital , Shanghai 200080 , People's Republic of China
| | - Chen-Lin Gao
- Faculty of Chinese Medicine, State Key Laboratory of Quality Research in Chinese Medicine , Macau University of Science and Technology , Avenida Wai Long , Taipa , Macao 999078 , People's Republic of China
- Department of Endocrinology , Affiliated Hospital of Southwest Medical University , Luzhou , Sichuan 646000 , People's Republic of China
| | - Jun-Ling Gu
- Faculty of Chinese Medicine, State Key Laboratory of Quality Research in Chinese Medicine , Macau University of Science and Technology , Avenida Wai Long , Taipa , Macao 999078 , People's Republic of China
| | - Wen-Jun Gan
- Faculty of Chinese Medicine, State Key Laboratory of Quality Research in Chinese Medicine , Macau University of Science and Technology , Avenida Wai Long , Taipa , Macao 999078 , People's Republic of China
| | - Wei Huang
- Department of Endocrinology , Affiliated Hospital of Southwest Medical University , Luzhou , Sichuan 646000 , People's Republic of China
| | - Yong Xu
- Department of Endocrinology , Affiliated Hospital of Southwest Medical University , Luzhou , Sichuan 646000 , People's Republic of China
| | - Hua Zhou
- Faculty of Chinese Medicine, State Key Laboratory of Quality Research in Chinese Medicine , Macau University of Science and Technology , Avenida Wai Long , Taipa , Macao 999078 , People's Republic of China
- Macau Institute for Applied Research in Medicine and Health , Avenida Wai Long , Taipa , Macao 999078 , People's Republic of China
| | - Wei-Ni Chen
- Department of Endocrinology , Zhuhai Hospital of Integrated Traditional Chinese and Western Medicine , Zhuhai 519000 , People's Republic of China
| | - Zhi-Long Liu
- Department of Endocrinology , Zhuhai Hospital of Integrated Traditional Chinese and Western Medicine , Zhuhai 519000 , People's Republic of China
| | - You-Hua Xu
- Faculty of Chinese Medicine, State Key Laboratory of Quality Research in Chinese Medicine , Macau University of Science and Technology , Avenida Wai Long , Taipa , Macao 999078 , People's Republic of China
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22
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Effects of menopause and high-intensity training on insulin sensitivity and muscle metabolism. Menopause 2019; 25:165-175. [PMID: 28953212 DOI: 10.1097/gme.0000000000000981] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
OBJECTIVE To investigate peripheral insulin sensitivity and skeletal muscle glucose metabolism in premenopausal and postmenopausal women, and evaluate whether exercise training benefits are maintained after menopause. METHODS Sedentary, healthy, normal-weight, late premenopausal (n = 21), and early postmenopausal (n = 20) women were included in a 3-month high-intensity exercise training intervention. Body composition was assessed by magnetic resonance imaging and dual-energy x-ray absorptiometry, whole body glucose disposal rate (GDR) by hyperinsulinemic euglycemic clamp (40 mU/m/min), and femoral muscle glucose uptake by positron emission tomography/computed tomography, using the glucose analog fluorodeoxyglucose, expressed as estimated metabolic rate (eMR). Insulin signaling was investigated in muscle biopsies. RESULTS Age difference between groups was 4.5 years, and no difference was observed in body composition. Training increased lean body mass (estimate [95% confidence interval] 0.5 [0.2-0.9] kg, P < 0.01) and thigh muscle mass (0.2 [-0.1 to 0.6] kg, P < 0.01), and decreased fat percentage (1.0 [0.5-1.5]%, P < 0.01) similarly in the two groups. The postmenopausal women had lower eMR in vastus lateralis muscle than the premenopausal women (-14.0 [-26.0 to -2.0] μmol/min/kg, P = 0.02), and tended to have lower eMR in femoral muscles (-11.2 [-22.7 to 0.4] μmol/min/kg, P = 0.06), and also GDR (-59.3 [-124.8 to 6.3] mg/min, P = 0.08), but increased similarly in both groups with training (eMR vastus lateralis muscle: 27.8 [19.6-36.0] μmol/min/kg, P < 0.01; eMR femoral muscle: 20.0 [13.1-26.7] μmol/min/kg, P < 0.01, respectively; GDR: 43.6 [10.4-76.9] mg/min, P = 0.01). Potential mechanisms underlying the training-induced increases in insulin sensitivity included increased expression of hexokinase (19.2 [5.0-24.7] AU, P = 0.02) and glycogen synthase (32.4 [15.0-49.8] AU, P < 0.01), and also increased insulin activation of Akt2 (20.6 [3.4-29.0], P = 0.03) and dephosphorylation of glycogen synthase (-41.8 [-82.9 to -0.7], P = 0.05). CONCLUSIONS Insulin sensitivity was reduced in early postmenopausal women. However, postmenopausal women increased peripheral insulin sensitivity, skeletal muscle insulin-stimulated glucose uptake, and skeletal muscle mass to the same extent as premenopausal women after 3 months of high-intensity exercise training.
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Dela F, Ingersen A, Andersen NB, Nielsen MB, Petersen HHH, Hansen CN, Larsen S, Wojtaszewski J, Helge JW. Effects of one-legged high-intensity interval training on insulin-mediated skeletal muscle glucose homeostasis in patients with type 2 diabetes. Acta Physiol (Oxf) 2019; 226:e13245. [PMID: 30585698 DOI: 10.1111/apha.13245] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Revised: 12/06/2018] [Accepted: 12/17/2018] [Indexed: 12/13/2022]
Abstract
AIM To examine the effect of high-intensity interval training (HIIT) on glucose clearance rates in skeletal muscle and explore the mechanism within the muscle. METHODS Ten males with type 2 diabetes mellitus (T2DM) and ten matched healthy subjects performed 2 weeks of one-legged HIIT (total of eight sessions, each comprised of 10 × 1 minute ergometer bicycle exercise at >80% of maximal heart rate, interspersed with one min of rest). Insulin sensitivity was assessed by an isoglycaemic, hyperinsulinaemic clamp combined with arteriovenous leg balance technique of the trained (T) and the untrained (UT) leg and muscle biopsies of both legs. RESULTS Insulin-stimulated glucose clearance in T legs was ~30% higher compared with UT legs in both groups due to increased blood flow in T vs UT legs and maintained glucose extraction. With each training session, muscle glycogen content decreased only in the training leg, and after the training, glycogen synthase and citrate synthase activities were higher in T vs UT legs. No major changes occurred in the expression of proteins in the insulin signalling cascade. Mitochondrial respiratory capacity was similar in T2DM and healthy subjects, and unchanged by HIIT. CONCLUSION HIIT improves skeletal muscle insulin sensitivity. With HIIT, the skeletal muscle of patients with T2DM becomes just as insulin sensitive as untrained muscle in healthy subjects. The mechanism includes oscillations in muscle glycogen stores and a maintained ability to extract glucose from the blood in the face of increased blood flow in the trained leg.
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Affiliation(s)
- Flemming Dela
- Xlab, Center for Healthy Aging, Department of Biomedical Sciences, Faculty of Health and Medical Sciences University of Copenhagen Copenhagen Denmark
- Department of Geriatrics Bispebjerg University Hospital Copenhagen Denmark
| | - Arthur Ingersen
- Xlab, Center for Healthy Aging, Department of Biomedical Sciences, Faculty of Health and Medical Sciences University of Copenhagen Copenhagen Denmark
| | - Nynne B. Andersen
- Xlab, Center for Healthy Aging, Department of Biomedical Sciences, Faculty of Health and Medical Sciences University of Copenhagen Copenhagen Denmark
| | - Maria B. Nielsen
- Xlab, Center for Healthy Aging, Department of Biomedical Sciences, Faculty of Health and Medical Sciences University of Copenhagen Copenhagen Denmark
| | - Helga H. H. Petersen
- Xlab, Center for Healthy Aging, Department of Biomedical Sciences, Faculty of Health and Medical Sciences University of Copenhagen Copenhagen Denmark
| | - Christina N. Hansen
- Xlab, Center for Healthy Aging, Department of Biomedical Sciences, Faculty of Health and Medical Sciences University of Copenhagen Copenhagen Denmark
| | - Steen Larsen
- Xlab, Center for Healthy Aging, Department of Biomedical Sciences, Faculty of Health and Medical Sciences University of Copenhagen Copenhagen Denmark
- Clinical Research Centre Medical University of Bialystok Bialystok Poland
| | - Jørgen Wojtaszewski
- Department of Nutrition, Exercise and Sports, Faculty of Science University of Copenhagen Copenhagen Denmark
| | - Jørn Wulff Helge
- Xlab, Center for Healthy Aging, Department of Biomedical Sciences, Faculty of Health and Medical Sciences University of Copenhagen Copenhagen Denmark
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Small L, Brandon AE, Parker BL, Deshpande V, Samsudeen AF, Kowalski GM, Reznick J, Wilks DL, Preston E, Bruce CR, James DE, Turner N, Cooney GJ. Reduced insulin action in muscle of high fat diet rats over the diurnal cycle is not associated with defective insulin signaling. Mol Metab 2019; 25:107-118. [PMID: 31029696 PMCID: PMC6600078 DOI: 10.1016/j.molmet.2019.04.006] [Citation(s) in RCA: 5] [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: 03/26/2019] [Revised: 04/04/2019] [Accepted: 04/08/2019] [Indexed: 12/02/2022] Open
Abstract
Objective Energy metabolism and insulin action follow a diurnal rhythm. It is therefore important that investigations into dysregulation of these pathways are relevant to the physiology of this diurnal rhythm. Methods We examined glucose uptake, markers of insulin action, and the phosphorylation of insulin signaling intermediates in muscle of chow and high fat, high sucrose (HFHS) diet-fed rats over the normal diurnal cycle. Results HFHS animals displayed hyperinsulinemia but had reduced systemic glucose disposal and lower muscle glucose uptake during the feeding period. Analysis of gene expression, enzyme activity, protein abundance and phosphorylation revealed a clear diurnal regulation of substrate oxidation pathways with no difference in Akt signaling in muscle. Transfection of a constitutively active Akt2 into the muscle of HFHS rats did not rescue diet-induced reductions in insulin-stimulated glucose uptake. Conclusions These studies suggest that reduced glucose uptake in muscle during the diurnal cycle induced by short-term HFHS-feeding is not the result of reduced insulin signaling. Investigating metabolism in rodents over the diurnal cycle more accurately models normal animal physiology. Diurnal regulation of substrate oxidation is altered in muscle of HFHS-fed rats. There is a disconnect between glucose uptake and canonical insulin signaling in muscle. Activation of Akt2 does not rescue diet-induced reductions in insulin-stimulated glucose uptake in muscle.
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Affiliation(s)
- Lewin Small
- Diabetes and Metabolism Division, The Garvan Institute of Medical Research, Sydney, NSW, Australia
| | - Amanda E Brandon
- Diabetes and Metabolism Division, The Garvan Institute of Medical Research, Sydney, NSW, Australia; The University of Sydney, School of Medical Science, Charles Perkins Centre D17, Sydney, NSW, Australia
| | - Benjamin L Parker
- The University of Sydney, School of Life and Environmental Science, Charles Perkins Centre D17, Sydney, NSW, Australia
| | - Vinita Deshpande
- The University of Sydney, School of Life and Environmental Science, Charles Perkins Centre D17, Sydney, NSW, Australia
| | - Azrah F Samsudeen
- Department of Pharmacology, School of Medical Science, University of New South Wales, Sydney, NSW, Australia
| | - Greg M Kowalski
- Deakin University, School of Exercise and Nutrition Sciences, Faculty of Health, Institute for Physical Activity and Nutrition, Geelong, Australia
| | - Jane Reznick
- Diabetes and Metabolism Division, The Garvan Institute of Medical Research, Sydney, NSW, Australia
| | - Donna L Wilks
- Diabetes and Metabolism Division, The Garvan Institute of Medical Research, Sydney, NSW, Australia
| | - Elaine Preston
- Diabetes and Metabolism Division, The Garvan Institute of Medical Research, Sydney, NSW, Australia
| | - Clinton R Bruce
- Deakin University, School of Exercise and Nutrition Sciences, Faculty of Health, Institute for Physical Activity and Nutrition, Geelong, Australia
| | - David E James
- The University of Sydney, School of Life and Environmental Science, Charles Perkins Centre D17, Sydney, NSW, Australia
| | - Nigel Turner
- Department of Pharmacology, School of Medical Science, University of New South Wales, Sydney, NSW, Australia
| | - Gregory J Cooney
- Diabetes and Metabolism Division, The Garvan Institute of Medical Research, Sydney, NSW, Australia; The University of Sydney, School of Medical Science, Charles Perkins Centre D17, Sydney, NSW, Australia.
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Steenberg DE, Jørgensen NB, Birk JB, Sjøberg KA, Kiens B, Richter EA, Wojtaszewski JFP. Exercise training reduces the insulin-sensitizing effect of a single bout of exercise in human skeletal muscle. J Physiol 2018; 597:89-103. [PMID: 30325018 DOI: 10.1113/jp276735] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Accepted: 10/11/2018] [Indexed: 12/26/2022] Open
Abstract
KEY POINTS A single bout of exercise is capable of increasing insulin sensitivity in human skeletal muscle. Whether this ability is affected by training status is not clear. Studies in mice suggest that the AMPK-TBC1D4 signalling axis is important for the increased insulin-stimulated glucose uptake after a single bout of exercise. The present study is the first longitudinal intervention study to show that, although exercise training increases insulin-stimulated glucose uptake in skeletal muscle at rest, it diminishes the ability of a single bout of exercise to enhance muscle insulin-stimulated glucose uptake. The present study provides novel data indicating that AMPK in human skeletal muscle is important for the insulin-sensitizing effect of a single bout of exercise. ABSTRACT Not only chronic exercise training, but also a single bout of exercise, increases insulin-stimulated glucose uptake in skeletal muscle. However, it is not well described how adaptations to exercise training affect the ability of a single bout of exercise to increase insulin sensitivity. Rodent studies suggest that the insulin-sensitizing effect of a single bout of exercise is AMPK-dependent (presumably via the α2 β2 γ3 AMPK complex). Whether this is also the case in humans is unknown. Previous studies have shown that exercise training decreases the expression of the α2 β2 γ3 AMPK complex and diminishes the activation of this complex during exercise. Thus, we hypothesized that exercise training diminishes the ability of a single bout of exercise to enhance muscle insulin sensitivity. We investigated nine healthy male subjects who performed one-legged knee-extensor exercise at the same relative intensity before and after 12 weeks of exercise training. Training increased V ̇ O 2 peak and expression of mitochondrial proteins in muscle, whereas the expression of AMPKγ3 was decreased. Training also increased whole body and muscle insulin sensitivity. Interestingly, insulin-stimulated glucose uptake in the acutely exercised leg was not enhanced further by training. Thus, the increase in insulin-stimulated glucose uptake following a single bout of one-legged exercise was lower in the trained vs. untrained state. This was associated with reduced signalling via confirmed α2 β2 γ3 AMPK downstream targets (ACC and TBC1D4). These results suggest that the insulin-sensitizing effect of a single bout of exercise is also AMPK-dependent in human skeletal muscle.
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Affiliation(s)
- Dorte E Steenberg
- Department of Nutrition, Exercise and Sports, Section of Molecular Physiology, University of Copenhagen, Copenhagen, Denmark
| | - Nichlas B Jørgensen
- Department of Nutrition, Exercise and Sports, Section of Molecular Physiology, University of Copenhagen, Copenhagen, Denmark
| | - Jesper B Birk
- Department of Nutrition, Exercise and Sports, Section of Molecular Physiology, University of Copenhagen, Copenhagen, Denmark
| | - Kim A Sjøberg
- Department of Nutrition, Exercise and Sports, Section of Molecular Physiology, University of Copenhagen, Copenhagen, Denmark
| | - Bente Kiens
- Department of Nutrition, Exercise and Sports, Section of Molecular Physiology, University of Copenhagen, Copenhagen, Denmark
| | - Erik A Richter
- Department of Nutrition, Exercise and Sports, Section of Molecular Physiology, University of Copenhagen, Copenhagen, Denmark
| | - Jørgen F P Wojtaszewski
- Department of Nutrition, Exercise and Sports, Section of Molecular Physiology, University of Copenhagen, Copenhagen, Denmark
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Shi H, Munk A, Nielsen TS, Daughtry MR, Larsson L, Li S, Høyer KF, Geisler HW, Sulek K, Kjøbsted R, Fisher T, Andersen MM, Shen Z, Hansen UK, England EM, Cheng Z, Højlund K, Wojtaszewski JFP, Yang X, Hulver MW, Helm RF, Treebak JT, Gerrard DE. Skeletal muscle O-GlcNAc transferase is important for muscle energy homeostasis and whole-body insulin sensitivity. Mol Metab 2018. [PMID: 29525407 PMCID: PMC6001359 DOI: 10.1016/j.molmet.2018.02.010] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Objective Given that cellular O-GlcNAcylation levels are thought to be real-time measures of cellular nutrient status and dysregulated O-GlcNAc signaling is associated with insulin resistance, we evaluated the role of O-GlcNAc transferase (OGT), the enzyme that mediates O-GlcNAcylation, in skeletal muscle. Methods We assessed O-GlcNAcylation levels in skeletal muscle from obese, type 2 diabetic people, and we characterized muscle-specific OGT knockout (mKO) mice in metabolic cages and measured energy expenditure and substrate utilization pattern using indirect calorimetry. Whole body insulin sensitivity was assessed using the hyperinsulinemic euglycemic clamp technique and tissue-specific glucose uptake was subsequently evaluated. Tissues were used for histology, qPCR, Western blot, co-immunoprecipitation, and chromatin immunoprecipitation analyses. Results We found elevated levels of O-GlcNAc-modified proteins in obese, type 2 diabetic people compared with well-matched obese and lean controls. Muscle-specific OGT knockout mice were lean, and whole body energy expenditure and insulin sensitivity were increased in these mice, consistent with enhanced glucose uptake and elevated glycolytic enzyme activities in skeletal muscle. Moreover, enhanced glucose uptake was also observed in white adipose tissue that was browner than that of WT mice. Interestingly, mKO mice had elevated mRNA levels of Il15 in skeletal muscle and increased circulating IL-15 levels. We found that OGT in muscle mediates transcriptional repression of Il15 by O-GlcNAcylating Enhancer of Zeste Homolog 2 (EZH2). Conclusions Elevated muscle O-GlcNAc levels paralleled insulin resistance and type 2 diabetes in humans. Moreover, OGT-mediated signaling is necessary for proper skeletal muscle metabolism and whole-body energy homeostasis, and our data highlight O-GlcNAcylation as a potential target for ameliorating metabolic disorders. Type 2 diabetic humans have elevated O-GlcNAc levels in skeletal muscle. Knockout of OGT in muscle elevates whole body insulin sensitivity. Knockout of OGT in muscle increases resistance to diet-induced obesity. Muscle-specific OGT knockout mice have elevated plasma IL-15 levels. OGT in muscle controls Il15 expression by O-GlcNAcylation and inhibition of EZH2.
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Affiliation(s)
- Hao Shi
- Department of Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
| | - Alexander Munk
- Section of Integrative Physiology, Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, DK2200, Denmark
| | - Thomas S Nielsen
- Section of Integrative Physiology, Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, DK2200, Denmark
| | - Morgan R Daughtry
- Department of Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
| | - Louise Larsson
- Section of Integrative Physiology, Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, DK2200, Denmark
| | - Shize Li
- Department of Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
| | - Kasper F Høyer
- Section of Integrative Physiology, Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, DK2200, Denmark; Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Aarhus, DK8000, Denmark
| | - Hannah W Geisler
- Department of Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
| | - Karolina Sulek
- Section of Integrative Physiology, Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, DK2200, Denmark
| | - Rasmus Kjøbsted
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Copenhagen, DK2100, Denmark
| | - Taylor Fisher
- Department of Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
| | - Marianne M Andersen
- Section of Integrative Physiology, Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, DK2200, Denmark
| | - Zhengxing Shen
- Department of Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
| | - Ulrik K Hansen
- Section of Integrative Physiology, Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, DK2200, Denmark
| | - Eric M England
- Department of Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
| | - Zhiyong Cheng
- Department of Human Nutrition, Foods, and Exercise, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
| | - Kurt Højlund
- Department of Endocrinology, Odense University Hospital, Odense, Denmark; Section of Molecular Diabetes and Metabolism, Institute of Molecular Medicine and Institute of Clinical Research, University of Southern Denmark, Odense, Denmark
| | - Jørgen F P Wojtaszewski
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Copenhagen, DK2100, Denmark
| | - Xiaoyong Yang
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Matthew W Hulver
- Department of Human Nutrition, Foods, and Exercise, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA; The Virginia Tech Metabolic Phenotyping Core, Blacksburg, VA 24061, USA
| | - Richard F Helm
- Department of Biochemistry, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
| | - Jonas T Treebak
- Section of Integrative Physiology, Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, DK2200, Denmark.
| | - David E Gerrard
- Department of Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA.
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Voss TS, Vendelbo MH, Kampmann U, Hingst JR, Wojtaszewski JFP, Svart MV, Møller N, Jessen N. Acute Hypoglycemia in Healthy Humans Impairs Insulin-Stimulated Glucose Uptake and Glycogen Synthase in Skeletal Muscle: A Randomized Clinical Study. Diabetes 2017; 66:2483-2494. [PMID: 28596236 DOI: 10.2337/db16-1559] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Accepted: 06/01/2017] [Indexed: 11/13/2022]
Abstract
Hypoglycemia is the leading limiting factor in glycemic management of insulin-treated diabetes. Skeletal muscle is the predominant site of insulin-mediated glucose disposal. Our study used a crossover design to test to what extent insulin-induced hypoglycemia affects glucose uptake in skeletal muscle and whether hypoglycemia counterregulation modulates insulin and catecholamine signaling and glycogen synthase activity in skeletal muscle. Nine healthy volunteers were examined on three randomized study days: 1) hyperinsulinemic hypoglycemia (bolus insulin), 2) hyperinsulinemic euglycemia (bolus insulin and glucose infusion), and 3) saline control with skeletal muscle biopsies taken just before, 30 min after, and 75 min after insulin/saline injection. During hypoglycemia, glucose levels reached a nadir of ∼2.0 mmol/L, and epinephrine rose to ∼900 pg/mL. Hypoglycemia impaired insulin-stimulated glucose disposal and glucose clearance in skeletal muscle, whereas insulin signaling in glucose transport was unaffected by hypoglycemia. Insulin-stimulated glycogen synthase activity was completely ablated during hyperinsulinemic hypoglycemia, and catecholamine signaling via cAMP-dependent protein kinase and phosphorylation of inhibiting sites on glycogen synthase all increased.
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Affiliation(s)
- Thomas S Voss
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
- Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Aarhus, Denmark
| | - Mikkel H Vendelbo
- Department of Nuclear Medicine and PET Centre, Aarhus University Hospital, Aarhus, Denmark
| | - Ulla Kampmann
- Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Aarhus, Denmark
| | - Janne R Hingst
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Jørgen F P Wojtaszewski
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Mads V Svart
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
- Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Aarhus, Denmark
| | - Niels Møller
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
- Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Aarhus, Denmark
| | - Niels Jessen
- Department of Clinical Pharmacology, Aarhus University Hospital, Aarhus, Denmark
- Department of Biomedicine, Aarhus University Hospital, Aarhus, Denmark
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Kjøbsted R, Wojtaszewski JFP, Treebak JT. Role of AMP-Activated Protein Kinase for Regulating Post-exercise Insulin Sensitivity. ACTA ACUST UNITED AC 2017; 107:81-126. [PMID: 27812978 DOI: 10.1007/978-3-319-43589-3_5] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Skeletal muscle insulin resistance precedes development of type 2 diabetes (T2D). As skeletal muscle is a major sink for glucose disposal, understanding the molecular mechanisms involved in maintaining insulin sensitivity of this tissue could potentially benefit millions of people that are diagnosed with insulin resistance. Regular physical activity in both healthy and insulin-resistant individuals is recognized as the single most effective intervention to increase whole-body insulin sensitivity and thereby positively affect glucose homeostasis. A single bout of exercise has long been known to increase glucose disposal in skeletal muscle in response to physiological insulin concentrations. While this effect is identified to be restricted to the previously exercised muscle, the molecular basis for an apparent convergence between exercise- and insulin-induced signaling pathways is incompletely known. In recent years, we and others have identified the Rab GTPase-activating protein, TBC1 domain family member 4 (TBC1D4) as a target of key protein kinases in the insulin- and exercise-activated signaling pathways. Our working hypothesis is that the AMP-activated protein kinase (AMPK) is important for the ability of exercise to insulin sensitize skeletal muscle through TBC1D4. Here, we aim to provide an overview of the current available evidence linking AMPK to post-exercise insulin sensitivity.
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Affiliation(s)
- Rasmus Kjøbsted
- Novo Nordisk Foundation Center for Basic Metabolic Research, Section of Integrative Physiology, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3b, 2200, Copenhagen, Denmark
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, 2100, Copenhagen, Denmark
| | - Jørgen F P Wojtaszewski
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, 2100, Copenhagen, Denmark
| | - Jonas T Treebak
- Novo Nordisk Foundation Center for Basic Metabolic Research, Section of Integrative Physiology, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3b, 2200, Copenhagen, Denmark.
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Berg SM, Havelund J, Hasler-Sheetal H, Kruse V, Pedersen AJT, Hansen AB, Nybo M, Beck-Nielsen H, Højlund K, Færgeman NJ. The heterozygous N291S mutation in the lipoprotein lipase gene impairs whole-body insulin sensitivity and affects a distinct set of plasma metabolites in humans. J Clin Lipidol 2017; 11:515-523.e6. [PMID: 28502509 DOI: 10.1016/j.jacl.2017.02.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2016] [Revised: 02/03/2017] [Accepted: 02/16/2017] [Indexed: 10/20/2022]
Abstract
BACKGROUND Mutations in the lipoprotein lipase gene causing decreased lipoprotein lipase activity are associated with surrogate markers of insulin resistance and the metabolic syndrome in humans. OBJECTIVE We investigated the hypothesis that a heterozygous lipoprotein lipase mutation (N291S) induces whole-body insulin resistance and alterations in the plasma metabolome. METHODS In 6 carriers of a heterozygous lipoprotein lipase mutation (N291S) and 11 age-matched and weight-matched healthy controls, we examined insulin sensitivity and substrate metabolism by euglycemic-hyperinsulinemic clamps combined with indirect calorimetry. Plasma samples were taken before and after the clamp (4 hours of physiological hyperinsulinemia), and metabolites were measured enzymatically or by gas chromatography-mass spectrometry. RESULTS Compared with healthy controls, heterozygous carriers of a defective lipoprotein lipase allele had elevated fasting plasma levels triglycerides (P < .006), and markedly impaired insulin-stimulated glucose disposal rates (P < .024) and nonoxidative glucose metabolism (P < .015). Plasma metabolite profiling demonstrated lower circulating levels of pyruvic acid and α-tocopherol in the N291S carriers than in controls both before and after stimulation with insulin (all >1.5-fold change and P < .05). CONCLUSION Heterozygous carriers with a defective lipoprotein lipase allele are less insulin sensitive and have increased plasma levels of nonesterified fatty acids and triglycerides. The heterozygous N291S carriers also have a distinct plasma metabolomic signature, which may serve as a diagnostic tool for deficient lipoprotein lipase activity and as a marker of lipid-induced insulin resistance.
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Affiliation(s)
- Sofia Mikkelsen Berg
- Department of Endocrinology, Odense University Hospital, Odense, Denmark; Department of Molecular Biology and Biochemistry, VILLUM Center for Bioanalytical Sciences, University of Southern Denmark, Odense, Denmark
| | - Jesper Havelund
- Department of Molecular Biology and Biochemistry, VILLUM Center for Bioanalytical Sciences, University of Southern Denmark, Odense, Denmark
| | - Harald Hasler-Sheetal
- Department of Molecular Biology and Biochemistry, VILLUM Center for Bioanalytical Sciences, University of Southern Denmark, Odense, Denmark; Department of Biology, University of Southern Denmark, Odense, Denmark; Nordic Center of Earth Evolution, NordCEE, Department of Biology, University of Southern Demark, Odense, Denmark
| | - Vibeke Kruse
- Department of Molecular Biology and Biochemistry, VILLUM Center for Bioanalytical Sciences, University of Southern Denmark, Odense, Denmark
| | | | | | - Mads Nybo
- Department of Clinical Biochemistry and Pharmacology, Odense University Hospital, Odense, Denmark
| | | | - Kurt Højlund
- Department of Endocrinology, Odense University Hospital, Odense, Denmark; The Section of Molecular Diabetes and Metabolism, Department of Clinical Research & Department of Molecular Medicine, University of Southern Denmark, Odense, Denmark
| | - Nils Joakim Færgeman
- Department of Molecular Biology and Biochemistry, VILLUM Center for Bioanalytical Sciences, University of Southern Denmark, Odense, Denmark.
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30
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Irimia JM, Meyer CM, Segvich DM, Surendran S, DePaoli-Roach AA, Morral N, Roach PJ. Lack of liver glycogen causes hepatic insulin resistance and steatosis in mice. J Biol Chem 2017; 292:10455-10464. [PMID: 28483921 DOI: 10.1074/jbc.m117.786525] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Revised: 05/06/2017] [Indexed: 01/16/2023] Open
Abstract
Disruption of the Gys2 gene encoding the liver isoform of glycogen synthase generates a mouse strain (LGSKO) that almost completely lacks hepatic glycogen, has impaired glucose disposal, and is pre-disposed to entering the fasted state. This study investigated how the lack of liver glycogen increases fat accumulation and the development of liver insulin resistance. Insulin signaling in LGSKO mice was reduced in liver, but not muscle, suggesting an organ-specific defect. Phosphorylation of components of the hepatic insulin-signaling pathway, namely IRS1, Akt, and GSK3, was decreased in LGSKO mice. Moreover, insulin stimulation of their phosphorylation was significantly suppressed, both temporally and in an insulin dose response. Phosphorylation of the insulin-regulated transcription factor FoxO1 was somewhat reduced and insulin treatment did not elicit normal translocation of FoxO1 out of the nucleus. Fat overaccumulated in LGSKO livers, showing an aberrant distribution in the acinus, an increase not explained by a reduction in hepatic triglyceride export. Rather, when administered orally to fasted mice, glucose was directed toward hepatic lipogenesis as judged by the activity, protein levels, and expression of several fatty acid synthesis genes, namely, acetyl-CoA carboxylase, fatty acid synthase, SREBP1c, chREBP, glucokinase, and pyruvate kinase. Furthermore, using cultured primary hepatocytes, we found that lipogenesis was increased by 40% in LGSKO cells compared with controls. Of note, the hepatic insulin resistance was not associated with increased levels of pro-inflammatory markers. Our results suggest that loss of liver glycogen synthesis diverts glucose toward fat synthesis, correlating with impaired hepatic insulin signaling and glucose disposal.
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Affiliation(s)
- Jose M Irimia
- From the Departments of Biochemistry and Molecular Biology and
| | | | - Dyann M Segvich
- From the Departments of Biochemistry and Molecular Biology and
| | - Sneha Surendran
- Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, Indiana 46202
| | | | - Nuria Morral
- Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, Indiana 46202
| | - Peter J Roach
- From the Departments of Biochemistry and Molecular Biology and
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31
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Maile CA, Hingst JR, Mahalingan KK, O'Reilly AO, Cleasby ME, Mickelson JR, McCue ME, Anderson SM, Hurley TD, Wojtaszewski JFP, Piercy RJ. A highly prevalent equine glycogen storage disease is explained by constitutive activation of a mutant glycogen synthase. Biochim Biophys Acta Gen Subj 2016; 1861:3388-3398. [PMID: 27592162 DOI: 10.1016/j.bbagen.2016.08.021] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Revised: 08/15/2016] [Accepted: 08/30/2016] [Indexed: 01/16/2023]
Abstract
BACKGROUND Equine type 1 polysaccharide storage myopathy (PSSM1) is associated with a missense mutation (R309H) in the glycogen synthase (GYS1) gene, enhanced glycogen synthase (GS) activity and excessive glycogen and amylopectate inclusions in muscle. METHODS Equine muscle biochemical and recombinant enzyme kinetic assays in vitro and homology modelling in silico, were used to investigate the hypothesis that higher GS activity in affected horse muscle is caused by higher GS expression, dysregulation, or constitutive activation via a conformational change. RESULTS PSSM1-affected horse muscle had significantly higher glycogen content than control horse muscle despite no difference in GS expression. GS activity was significantly higher in muscle from homozygous mutants than from heterozygote and control horses, in the absence and presence of the allosteric regulator, glucose 6 phosphate (G6P). Muscle from homozygous mutant horses also had significantly increased GS phosphorylation at sites 2+2a and significantly higher AMPKα1 (an upstream kinase) expression than controls, likely reflecting a physiological attempt to reduce GS enzyme activity. Recombinant mutant GS was highly active with a considerably lower Km for UDP-glucose, in the presence and absence of G6P, when compared to wild type GS, and despite its phosphorylation. CONCLUSIONS Elevated activity of the mutant enzyme is associated with ineffective regulation via phosphorylation rendering it constitutively active. Modelling suggested that the mutation disrupts a salt bridge that normally stabilises the basal state, shifting the equilibrium to the enzyme's active state. GENERAL SIGNIFICANCE This study explains the gain of function pathogenesis in this highly prevalent polyglucosan myopathy.
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Affiliation(s)
- C A Maile
- Comparative Neuromuscular Diseases Laboratory, Department of Clinical Sciences and Services, Royal Veterinary College, London, UK
| | - J R Hingst
- Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Denmark
| | - K K Mahalingan
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, USA
| | - A O O'Reilly
- School of Natural Sciences and Psychology, Liverpool John Moores University, Liverpool, UK
| | - M E Cleasby
- Department of Comparative Biomedical Sciences, Royal Veterinary College, London, UK
| | - J R Mickelson
- Veterinary Biomedical Sciences Department, University of Minnesota, St. Paul, MN, USA
| | - M E McCue
- Veterinary Population Medicine Department, University of Minnesota, St. Paul, MN, USA
| | - S M Anderson
- Veterinary Population Medicine Department, University of Minnesota, St. Paul, MN, USA
| | - T D Hurley
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, USA
| | - J F P Wojtaszewski
- Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Denmark
| | - R J Piercy
- Comparative Neuromuscular Diseases Laboratory, Department of Clinical Sciences and Services, Royal Veterinary College, London, UK.
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Kjøbsted R, Pedersen AJT, Hingst JR, Sabaratnam R, Birk JB, Kristensen JM, Højlund K, Wojtaszewski JFP. Intact Regulation of the AMPK Signaling Network in Response to Exercise and Insulin in Skeletal Muscle of Male Patients With Type 2 Diabetes: Illumination of AMPK Activation in Recovery From Exercise. Diabetes 2016; 65:1219-30. [PMID: 26822091 DOI: 10.2337/db15-1034] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2015] [Accepted: 01/16/2016] [Indexed: 11/13/2022]
Abstract
Current evidence on exercise-mediated AMPK regulation in skeletal muscle of patients with type 2 diabetes (T2D) is inconclusive. This may relate to inadequate segregation of trimeric complexes in the investigation of AMPK activity. We examined the regulation of AMPK and downstream targets ACC-β, TBC1D1, and TBC1D4 in muscle biopsy specimens obtained from 13 overweight/obese patients with T2D and 14 weight-matched male control subjects before, immediately after, and 3 h after exercise. Exercise increased AMPK α2β2γ3 activity and phosphorylation of ACCβ Ser(221), TBC1D1 Ser(237)/Thr(596), and TBC1D4 Ser(704) Conversely, exercise decreased AMPK α1β2γ1 activity and TBC1D4 Ser(318)/Thr(642) phosphorylation. Interestingly, compared with preexercise, 3 h into exercise recovery, AMPK α2β2γ1 and α1β2γ1 activity were increased concomitant with increased TBC1D4 Ser(318)/Ser(341)/Ser(704) phosphorylation. No differences in these responses were observed between patients with T2D and control subjects. Subjects were also studied by euglycemic-hyperinsulinemic clamps performed at rest and 3 h after exercise. We found no evidence for insulin to regulate AMPK activity. Thus, AMPK signaling is not compromised in muscle of patients with T2D during exercise and insulin stimulation. Our results reveal a hitherto unrecognized activation of specific AMPK complexes in exercise recovery. We hypothesize that the differential regulation of AMPK complexes plays an important role for muscle metabolism and adaptations to exercise.
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Affiliation(s)
- Rasmus Kjøbsted
- Section of Molecular Physiology, August Krogh Centre, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | | | - Janne R Hingst
- Section of Molecular Physiology, August Krogh Centre, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Rugivan Sabaratnam
- Department of Endocrinology, Odense University Hospital, Odense, Denmark Section of Molecular Diabetes and Metabolism, Institute of Molecular Medicine and Institute of Clinical Research, University of Southern Denmark, Odense, Denmark
| | - Jesper B Birk
- Section of Molecular Physiology, August Krogh Centre, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Jonas M Kristensen
- Department of Endocrinology, Odense University Hospital, Odense, Denmark Section of Molecular Diabetes and Metabolism, Institute of Molecular Medicine and Institute of Clinical Research, University of Southern Denmark, Odense, Denmark
| | - Kurt Højlund
- Department of Endocrinology, Odense University Hospital, Odense, Denmark Section of Molecular Diabetes and Metabolism, Institute of Molecular Medicine and Institute of Clinical Research, University of Southern Denmark, Odense, Denmark
| | - Jørgen F P Wojtaszewski
- Section of Molecular Physiology, August Krogh Centre, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
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Kruse R, Vind BF, Petersson SJ, Kristensen JM, Højlund K. Markers of autophagy are adapted to hyperglycaemia in skeletal muscle in type 2 diabetes. Diabetologia 2015; 58:2087-95. [PMID: 26048236 DOI: 10.1007/s00125-015-3654-0] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2014] [Accepted: 05/15/2015] [Indexed: 01/07/2023]
Abstract
AIMS/HYPOTHESIS Autophagy is a catabolic process that maintains cellular homeostasis by degradation of protein aggregates and selective removal of damaged organelles, e.g. mitochondria (mitophagy). Insulin resistance in skeletal muscle has been linked to mitochondrial dysfunction and altered protein metabolism. Here, we investigated whether abnormalities in autophagy are present in human muscle in obesity and type 2 diabetes. METHODS Using a case-control design, skeletal muscle biopsies obtained in the basal and insulin-stimulated states from patients with type 2 diabetes during both euglycaemia and hyperglycaemia, and from glucose-tolerant lean and obese individuals during euglycaemia, were used for analysis of mRNA levels, protein abundance and phosphorylation of autophagy-related proteins. RESULTS Muscle transcript levels of autophagy-related genes (ULK1, BECN1, PIK3C3, ATG5, ATG7, ATG12, GABARAPL1, MAP1LC3B, SQSTM1, TP53INP2 and FOXO3A [also known as FOXO3]), including some specific for mitophagy (BNIP3, BNIP3L and MUL1), and protein abundance of autophagy-related gene (ATG)7 and Bcl-2/adenovirus E1B 19-kDa-interacting protein 3 (BNIP3), as well as content and phosphorylation of forkhead box O3A (FOXO3A) were similar among the groups. Insulin reduced lipidation of microtubule-associated protein light chain 3 (LC3)B-I to LC3B-II, a marker of autophagosome formation, with no effect on p62/sequestosome 1 (SQSTM1) content in muscle of lean and obese individuals. In diabetic patients, insulin action on LC3B was absent and p62/SQSTM1 content increased when studied under euglycaemia, whereas the responses of LC3B and p62/SQSTM1 to insulin were normalised during hyperglycaemia. CONCLUSIONS/INTERPRETATION Our results demonstrate that the levels of autophagy-related genes and proteins in muscle are normal in obesity and type 2 diabetes. This suggests that muscle autophagy in type 2 diabetes has adapted to hyperglycaemia, which may contribute to preserve muscle mass.
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Affiliation(s)
- Rikke Kruse
- The Section of Molecular Diabetes & Metabolism, Institute of Clinical Research and Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark
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Pedersen AJT, Hingst JR, Friedrichsen M, Kristensen JM, Højlund K, Wojtaszewski JFP. Dysregulation of muscle glycogen synthase in recovery from exercise in type 2 diabetes. Diabetologia 2015; 58:1569-78. [PMID: 25870023 DOI: 10.1007/s00125-015-3582-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Accepted: 03/13/2015] [Indexed: 12/31/2022]
Abstract
AIMS/HYPOTHESIS Insulin and exercise stimulate skeletal muscle glycogen synthase (GS) activity by dephosphorylation and changes in kinetic properties. The aim of this study was to investigate the effects of insulin, exercise and post-exercise insulin stimulation on GS phosphorylation, activity and substrate affinity in obesity and type 2 diabetes. METHODS Obese men with type 2 diabetes (n = 13) and weight-matched controls (n = 14) underwent euglycaemic-hyperinsulinaemic clamps in the rested state and 3 h after 60 min of cycling (70% maximal pulmonary oxygen uptake [VO2max]). Biopsies from vastus lateralis muscle were obtained before and after clamps, and before and immediately after exercise. RESULTS Insulin-stimulated glucose uptake was lower in diabetic patients vs obese controls with or without prior exercise. Post exercise, glucose partitioning shifted away from oxidation and towards storage in both groups. Insulin and, more potently, exercise increased GS activity (fractional velocity [FV]) and substrate affinity in both groups. Both stimuli caused dephosphorylation of GS at sites 3a + 3b, with exercise additionally decreasing phosphorylation at sites 2 + 2a. In both groups, changes in GS activity, substrate affinity and dephosphorylation at sites 3a + 3b by exercise were sustained 3 h post exercise and further enhanced by insulin. Post exercise, reduced GS activity and substrate affinity as well as increased phosphorylation at sites 2 + 2a were found in diabetic patients vs obese controls. CONCLUSIONS/INTERPRETATION Exercise-induced activation of muscle GS in obesity and type 2 diabetes involves dephosphorylation of GS at sites 3a + 3b and 2 + 2a and enhanced substrate affinity, which is likely to facilitate glucose partitioning towards storage. Lower GS activity and increased phosphorylation at sites 2 + 2a in type 2 diabetes in the recovery period imply an impaired response to exercise.
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Kolnes AJ, Birk JB, Eilertsen E, Stuenæs JT, Wojtaszewski JFP, Jensen J. Epinephrine-stimulated glycogen breakdown activates glycogen synthase and increases insulin-stimulated glucose uptake in epitrochlearis muscles. Am J Physiol Endocrinol Metab 2015; 308:E231-40. [PMID: 25465888 DOI: 10.1152/ajpendo.00282.2014] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Epinephrine increases glycogen synthase (GS) phosphorylation and decreases GS activity but also stimulates glycogen breakdown, and low glycogen content normally activates GS. To test the hypothesis that glycogen content directly regulates GS phosphorylation, glycogen breakdown was stimulated in condition with decreased GS activation. Saline or epinephrine (0.02 mg/100 g rat) was injected subcutaneously in Wistar rats (∼130 g) with low (24-h-fasted), normal (normal diet), and high glycogen content (fasted-refed), and epitrochlearis muscles were removed after 3 h and incubated ex vivo, eliminating epinephrine action. Epinephrine injection reduced glycogen content in epitrochlearis muscles with high (120.7 ± 17.8 vs. 204.6 ± 14.5 mmol/kg, P < 0.01) and normal glycogen (89.5 ± 7.6 vs. 152 ± 8.1 mmol/kg, P < 0.01), but not significantly in muscles with low glycogen (90.0 ± 5.0 vs. 102.8 ± 7.8 mmol/kg, P = 0.17). In saline-injected rats, GS phosphorylation at sites 2+2a, 3a+3b, and 1b was higher and GS activity lower in muscles with high compared with low glycogen. GS sites 2+2a and 3a+3b phosphorylation decreased and GS activity increased in muscles where epinephrine decreased glycogen content; these parameters were unchanged in epitrochlearis from fasted rats where epinephrine injection did not decrease glycogen content. Incubation with insulin decreased GS site 3a+3b phosphorylation independently of glycogen content. Insulin-stimulated glucose uptake was increased in muscles where epinephrine injection decreased glycogen content. In conclusion, epinephrine stimulates glycogenolysis in epitrochlearis muscles with normal and high, but not low, glycogen content. Epinephrine-stimulated glycogenolysis decreased GS phosphorylation and increased GS activity. These data for the first time document direct regulation of GS phosphorylation by glycogen content.
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Affiliation(s)
- Anders J Kolnes
- Charles University Third Faculty of Medicine, Prague, Czech Republic
| | - Jesper B Birk
- Molecular Physiology Group, The August Krogh Centre, Department of Nutrition, Exercise and Sports, Copenhagen University, Copenhagen, Denmark
| | - Einar Eilertsen
- National Institute of Occupational Health, Oslo, Norway; and
| | - Jorid T Stuenæs
- National Institute of Occupational Health, Oslo, Norway; and
| | - Jørgen F P Wojtaszewski
- Molecular Physiology Group, The August Krogh Centre, Department of Nutrition, Exercise and Sports, Copenhagen University, Copenhagen, Denmark
| | - Jørgen Jensen
- Molecular Physiology Group, The August Krogh Centre, Department of Nutrition, Exercise and Sports, Copenhagen University, Copenhagen, Denmark; Department of Physical Performance, Norwegian School of Sports Sciences, Oslo, Norway
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Albers PH, Pedersen AJT, Birk JB, Kristensen DE, Vind BF, Baba O, Nøhr J, Højlund K, Wojtaszewski JFP. Human muscle fiber type-specific insulin signaling: impact of obesity and type 2 diabetes. Diabetes 2015; 64:485-97. [PMID: 25187364 DOI: 10.2337/db14-0590] [Citation(s) in RCA: 141] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Skeletal muscle is a heterogeneous tissue composed of different fiber types. Studies suggest that insulin-mediated glucose metabolism is different between muscle fiber types. We hypothesized that differences are due to fiber type-specific expression/regulation of insulin signaling elements and/or metabolic enzymes. Pools of type I and II fibers were prepared from biopsies of the vastus lateralis muscles from lean, obese, and type 2 diabetic subjects before and after a hyperinsulinemic-euglycemic clamp. Type I fibers compared with type II fibers have higher protein levels of the insulin receptor, GLUT4, hexokinase II, glycogen synthase (GS), and pyruvate dehydrogenase-E1α (PDH-E1α) and a lower protein content of Akt2, TBC1 domain family member 4 (TBC1D4), and TBC1D1. In type I fibers compared with type II fibers, the phosphorylation response to insulin was similar (TBC1D4, TBC1D1, and GS) or decreased (Akt and PDH-E1α). Phosphorylation responses to insulin adjusted for protein level were not different between fiber types. Independently of fiber type, insulin signaling was similar (TBC1D1, GS, and PDH-E1α) or decreased (Akt and TBC1D4) in muscle from patients with type 2 diabetes compared with lean and obese subjects. We conclude that human type I muscle fibers compared with type II fibers have a higher glucose-handling capacity but a similar sensitivity for phosphoregulation by insulin.
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Affiliation(s)
- Peter H Albers
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, August Krogh Centre, University of Copenhagen, Copenhagen, Denmark Diabetes Research Unit, Novo Nordisk A/S, Maaloev, Denmark
| | - Andreas J T Pedersen
- Department of Endocrinology, Diabetes Research Center, Odense University Hospital, Odense, Denmark
| | - Jesper B Birk
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, August Krogh Centre, University of Copenhagen, Copenhagen, Denmark
| | - Dorte E Kristensen
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, August Krogh Centre, University of Copenhagen, Copenhagen, Denmark
| | - Birgitte F Vind
- Department of Endocrinology, Diabetes Research Center, Odense University Hospital, Odense, Denmark
| | - Otto Baba
- Section of Biology, Department of Oral Function and Molecular Biology, School of Dentistry, Ohu University, Koriyama, Japan
| | - Jane Nøhr
- Diabetes Research Unit, Novo Nordisk A/S, Maaloev, Denmark
| | - Kurt Højlund
- Department of Endocrinology, Diabetes Research Center, Odense University Hospital, Odense, Denmark
| | - Jørgen F P Wojtaszewski
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, August Krogh Centre, University of Copenhagen, Copenhagen, Denmark
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Yu Y, Chai J. The function of miRNAs and their potential as therapeutic targets in burn-induced insulin resistance (review). Int J Mol Med 2014; 35:305-10. [PMID: 25484249 DOI: 10.3892/ijmm.2014.2023] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2014] [Accepted: 12/03/2014] [Indexed: 11/06/2022] Open
Abstract
Burns are common accidental injuries. The main clinical manifestations of severe burn injury are insulin resistance and high metabolism. Insulin resistance results in hyperglycemia, which may lead to skeletal muscle wasting and suspended wound healing. It also elevates the risk of infection and sepsis. Studies have indicated that insulin receptor (IR) and insulin receptor substrate 1 (IRS1) are essential factors involved in the regulation of blood glucose levels. Moreover, the suppression of the IR/IRS1 signaling pathway results in insulin resistance. Recent studies have also indicated that miRNAs, which are small non-coding RNAs consisting of 20-23 nucleotides, target the 3'-untranslated region (3'-UTR) of IRS1 mRNA and attenuate protein translation. miRNAs also play an important role in the development of type II diabetes (T2D) and obesity-induced insulin resistance. In the present review, we discuss the involvement of miRNAs in burn-induced insulin resistance through the targeting of the IR/IRS1 signaling pathway. We also discuss the possibility of miRNAs a novel therapeutic target in insulin resistance in burn patients.
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Affiliation(s)
- Yonghui Yu
- Department of Burn and Plastic Surgery, The First Affiliated Hospital of PLA General Hospital, Beijing 100048, P.R. China
| | - Jiake Chai
- Department of Burn and Plastic Surgery, The First Affiliated Hospital of PLA General Hospital, Beijing 100048, P.R. China
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Sato S, Ogura Y, Tajrishi MM, Kumar A. Elevated levels of TWEAK in skeletal muscle promote visceral obesity, insulin resistance, and metabolic dysfunction. FASEB J 2014; 29:988-1002. [PMID: 25466899 DOI: 10.1096/fj.14-260703] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Skeletal muscle is responsible for the majority of glucose disposal in body. Impairment in skeletal muscle glucose handling capacity leads to the state of insulin resistance. The TNF-like weak inducer of apoptosis (TWEAK) cytokine has now emerged as a major regulator of skeletal muscle mass and function. However, the role of TWEAK in skeletal muscle metabolic function remains less understood. Here, we demonstrate that with progressive age, skeletal muscle-specific TWEAK-transgenic (TWEAK-Tg) mice gain increased body weight (∼16%) and fat mass (∼64%) and show glucose intolerance and insulin insensitivity. TWEAK-Tg mice also exhibit adipocyte hypertrophy in the epididymal fat. Oxygen uptake, voluntary physical activity, and exercise capacity were significantly reduced in TWEAK-Tg mice compared with controls. Overexpression of TWEAK inhibited (∼31%) 5' AMP-activated protein kinase (AMPK) and reduced (∼31%) the levels of glucose transporter type 4 (GLUT4) without affecting the Akt pathway. TWEAK also inhibited insulin-stimulated glucose uptake (∼32%) and repressed the levels of GLUT4 (∼50%) in cultured myotubes from C57BL6 mice. TWEAK represses the levels of Krüppel-like factor 15; myocyte enhancer factor 2, and peroxisome proliferator-activated receptor-γ coactivator-1α, which are required for the activation of the GLUT4 locus. Collectively our study demonstrates that elevated levels of TWEAK in skeletal muscle cause metabolic abnormalities. Inhibition of TWEAK could be a potential approach to prevent weight gain and type 2 diabetes.
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Affiliation(s)
- Shuichi Sato
- Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, Louisville, Kentucky, USA
| | - Yuji Ogura
- Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, Louisville, Kentucky, USA
| | - Marjan M Tajrishi
- Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, Louisville, Kentucky, USA
| | - Ashok Kumar
- Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, Louisville, Kentucky, USA
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Kristensen JM, Skov V, Petersson SJ, Ørtenblad N, Wojtaszewski JFP, Beck-Nielsen H, Højlund K. A PGC-1α- and muscle fibre type-related decrease in markers of mitochondrial oxidative metabolism in skeletal muscle of humans with inherited insulin resistance. Diabetologia 2014; 57:1006-15. [PMID: 24510228 DOI: 10.1007/s00125-014-3187-y] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Accepted: 01/17/2014] [Indexed: 12/25/2022]
Abstract
AIMS/HYPOTHESIS Insulin resistance in obesity and type 2 diabetes is related to abnormalities in mitochondrial oxidative phosphorylation (OxPhos) in skeletal muscle. We tested the hypothesis that mitochondrial oxidative metabolism is impaired in muscle of patients with inherited insulin resistance and defective insulin signalling. METHODS Skeletal muscle biopsies obtained from carriers (n = 6) of a mutation in the tyrosine kinase domain of the insulin receptor gene (INSR) and matched healthy controls (n = 15) were used for discovery-mode microarray-based transcriptional profiling combined with biological pathway analysis. Findings were validated by quantitative real-time PCR, immunoblotting and activity assays. RESULTS In INSR mutation carriers, insulin resistance was associated with a coordinated downregulation of OxPhos genes in skeletal muscle. This was related to a 46% decrease in mRNA levels (p = 0.036) of peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α), and 25-50% lower protein content of OxPhos subunits encoded by mitochondrial (ND6, p = 0.042) and nuclear DNA (UQCRC1, p = 0.001; SDHA, p = 0.067; COX5A, p = 0.017 and ATP5B, p = 0.005), as well as reduced citrate synthase activity (p = 0.025). Moreover, mutation carriers showed a marked reduction in type 1 muscle fibres (35% vs 62%, p = 0.0005) and increased type 2a fibres (53% vs 32%; p = 0.002) compared with controls. There were no differences in protein content and phosphorylation of 5' AMP-activated protein kinase, p38 mitogen-activated protein kinase, Erk1 and Erk2. CONCLUSIONS/INTERPRETATION These data indicate that inherited insulin resistance coincides with reduced mitochondrial oxidative capacity in a PGC-1α- and muscle fibre type-related manner. Whether this co-existence is directly or indirectly related to insulin resistance remains to be elucidated.
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Affiliation(s)
- Jonas M Kristensen
- Department of Endocrinology, Odense University Hospital, Kløvervænget 6, 4, 5000, Odense C, Denmark
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40
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Turnbull J, Tiberia E, Pereira S, Zhao X, Pencea N, Wheeler AL, Yu WQ, Ivovic A, Naranian T, Israelian N, Draginov A, Piliguian M, Frankland PW, Wang P, Ackerley CA, Giacca A, Minassian BA. Deficiency of a glycogen synthase-associated protein, Epm2aip1, causes decreased glycogen synthesis and hepatic insulin resistance. J Biol Chem 2013; 288:34627-37. [PMID: 24142699 DOI: 10.1074/jbc.m113.483198] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Glycogen synthesis is a major component of the insulin response, and defective glycogen synthesis is a major portion of insulin resistance. Insulin regulates glycogen synthase (GS) through incompletely defined pathways that activate the enzyme through dephosphorylation and, more potently, allosteric activation. We identify Epm2aip1 as a GS-associated protein. We show that the absence of Epm2aip1 in mice impairs allosteric activation of GS by glucose 6-phosphate, decreases hepatic glycogen synthesis, increases liver fat, causes hepatic insulin resistance, and protects against age-related obesity. Our work identifies a novel GS-associated GS activity-modulating component of insulin resistance.
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41
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Sylow L, Jensen TE, Kleinert M, Højlund K, Kiens B, Wojtaszewski J, Prats C, Schjerling P, Richter EA. Rac1 signaling is required for insulin-stimulated glucose uptake and is dysregulated in insulin-resistant murine and human skeletal muscle. Diabetes 2013; 62:1865-75. [PMID: 23423567 PMCID: PMC3661612 DOI: 10.2337/db12-1148] [Citation(s) in RCA: 143] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The actin cytoskeleton-regulating GTPase Rac1 is required for insulin-stimulated GLUT4 translocation in cultured muscle cells. However, involvement of Rac1 and its downstream signaling in glucose transport in insulin-sensitive and insulin-resistant mature skeletal muscle has not previously been investigated. We hypothesized that Rac1 and its downstream target, p21-activated kinase (PAK), are regulators of insulin-stimulated glucose uptake in mouse and human skeletal muscle and are dysregulated in insulin-resistant states. Muscle-specific inducible Rac1 knockout (KO) mice and pharmacological inhibition of Rac1 were used to determine whether Rac1 regulates insulin-stimulated glucose transport in mature skeletal muscle. Furthermore, Rac1 and PAK1 expression and signaling were investigated in muscle of insulin-resistant mice and humans. Inhibition and KO of Rac1 decreased insulin-stimulated glucose transport in mouse soleus and extensor digitorum longus muscles ex vivo. Rac1 KO mice showed decreased insulin and glucose tolerance and trended toward higher plasma insulin concentrations after intraperitoneal glucose injection. Rac1 protein expression and insulin-stimulated PAK(Thr423) phosphorylation were decreased in muscles of high fat-fed mice. In humans, insulin-stimulated PAK activation was decreased in both acute insulin-resistant (intralipid infusion) and chronic insulin-resistant states (obesity and diabetes). These findings show that Rac1 is a regulator of insulin-stimulated glucose uptake and a novel candidate involved in skeletal muscle insulin resistance.
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Affiliation(s)
- Lykke Sylow
- Molecular Physiology Group, Department of Nutrition, Exercise, and Sports, August Krogh Centre, University of Copenhagen, Copenhagen, Denmark
| | - Thomas E. Jensen
- Molecular Physiology Group, Department of Nutrition, Exercise, and Sports, August Krogh Centre, University of Copenhagen, Copenhagen, Denmark
| | - Maximilian Kleinert
- Molecular Physiology Group, Department of Nutrition, Exercise, and Sports, August Krogh Centre, University of Copenhagen, Copenhagen, Denmark
| | - Kurt Højlund
- Diabetes Research Center, Department of Endocrinology, Odense University Hospital, Odense, Denmark
| | - Bente Kiens
- Molecular Physiology Group, Department of Nutrition, Exercise, and Sports, August Krogh Centre, University of Copenhagen, Copenhagen, Denmark
| | - Jørgen Wojtaszewski
- Molecular Physiology Group, Department of Nutrition, Exercise, and Sports, August Krogh Centre, University of Copenhagen, Copenhagen, Denmark
| | - Clara Prats
- Department of Biomedical Sciences, Center of Healthy Aging, University of Copenhagen, Copenhagen, Denmark
| | - Peter Schjerling
- Institute of Sports Medicine, Department of Orthopedic Surgery, Bispebjerg Hospital and Center for Healthy Aging, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Erik A. Richter
- Molecular Physiology Group, Department of Nutrition, Exercise, and Sports, August Krogh Centre, University of Copenhagen, Copenhagen, Denmark
- Corresponding author: Erik A. Richter,
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42
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Tonks KT, Ng Y, Miller S, Coster ACF, Samocha-Bonet D, Iseli TJ, Xu A, Patrick E, Yang JYH, Junutula JR, Modrusan Z, Kolumam G, Stöckli J, Chisholm DJ, James DE, Greenfield JR. Impaired Akt phosphorylation in insulin-resistant human muscle is accompanied by selective and heterogeneous downstream defects. Diabetologia 2013; 56:875-85. [PMID: 23344726 DOI: 10.1007/s00125-012-2811-y] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2012] [Accepted: 11/29/2012] [Indexed: 01/04/2023]
Abstract
AIMS/HYPOTHESIS Muscle insulin resistance, one of the earliest defects associated with type 2 diabetes, involves changes in the phosphoinositide 3-kinase/Akt network. The relative contribution of obesity vs insulin resistance to perturbations in this pathway is poorly understood. METHODS We used phosphospecific antibodies against targets in the Akt signalling network to study insulin action in muscle from lean, overweight/obese and type 2 diabetic individuals before and during a hyperinsulinaemic-euglycaemic clamp. RESULTS Insulin-stimulated Akt phosphorylation at Thr309 and Ser474 was highly correlated with whole-body insulin sensitivity. In contrast, impaired phosphorylation of Akt substrate of 160 kDa (AS160; also known as TBC1D4) was associated with adiposity, but not insulin sensitivity. Neither insulin sensitivity nor obesity was associated with defective insulin-dependent phosphorylation of forkhead box O (FOXO) transcription factor. In view of the resultant basal hyperinsulinaemia, we predicted that this selective response within the Akt pathway might lead to hyperactivation of those processes that were spared. Indeed, the expression of genes targeted by FOXO was downregulated in insulin-resistant individuals. CONCLUSIONS/INTERPRETATION These results highlight non-linearity in Akt signalling and suggest that: (1) the pathway from Akt to glucose transport is complex; and (2) pathways, particularly FOXO, that are not insulin-resistant, are likely to be hyperactivated in response to hyperinsulinaemia. This facet of Akt signalling may contribute to multiple features of the metabolic syndrome.
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Affiliation(s)
- K T Tonks
- Diabetes and Obesity Research Program, Garvan Institute of Medical Research, 384 Victoria Street, Darlinghurst, 2010 NSW, Australia
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43
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Friedrichsen M, Birk JB, Richter EA, Ribel-Madsen R, Pehmøller C, Hansen BF, Beck-Nielsen H, Hirshman MF, Goodyear LJ, Vaag A, Poulsen P, Wojtaszewski JFP. Akt2 influences glycogen synthase activity in human skeletal muscle through regulation of NH₂-terminal (sites 2 + 2a) phosphorylation. Am J Physiol Endocrinol Metab 2013; 304:E631-9. [PMID: 23321478 PMCID: PMC3774094 DOI: 10.1152/ajpendo.00494.2012] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Type 2 diabetes is characterized by reduced muscle glycogen synthesis. The key enzyme in this process, glycogen synthase (GS), is activated via proximal insulin signaling, but the exact molecular events remain unknown. Previously, we demonstrated that phosphorylation of Thr³⁰⁸ on Akt (p-Akt-Thr³⁰⁸), Akt2 activity, and GS activity in muscle were positively associated with insulin sensitivity. Here, in the same study population, we determined the influence of several upstream elements in the canonical PI3K signaling on muscle GS activation. One-hundred eighty-one nondiabetic twins were examined with the euglycemic hyperinsulinemic clamp combined with excision of muscle biopsies. Insulin signaling was evaluated at the levels of the insulin receptor, IRS-1-associated PI3K (IRS-1-PI3K), Akt, and GS employing activity assays and phosphospecific Western blotting. The insulin-stimulated GS activity was positively associated with p-Akt-Thr³⁰⁸ (P = 0.01) and Akt2 activity (P = 0.04) but not p-Akt-Ser⁴⁷³ or IRS-1-PI3K activity. Furthermore, p-Akt-Thr³⁰⁸ and Akt2 activity were negatively associated with NH₂-terminal GS phosphorylation (P = 0.001 for both), which in turn was negatively associated with insulin-stimulated GS activity (P < 0.001). We found no association between COOH-terminal GS phosphorylation and Akt or GS activity. Employing whole body Akt2-knockout mice, we validated the necessity for Akt2 in insulin-mediated GS activation. However, since insulin did not affect NH₂-terminal phosphorylation in mice, we could not use this model to validate the observed association between GS NH₂-terminal phosphorylation and Akt activity in humans. In conclusion, our study suggests that although COOH-terminal dephosphorylation is likely necessary for GS activation, Akt2-dependent NH₂-terminal dephosphorylation may be the site for "fine-tuning" insulin-mediated GS activation in humans.
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Gomez-Monterrey I, Sala M, Rusciano MR, Monaco S, Maione AS, Iaccarino G, Tortorella P, D'Ursi AM, Scrima M, Carotenuto A, De Rosa G, Bertamino A, Vernieri E, Grieco P, Novellino E, Illario M, Campiglia P. Characterization of a selective CaMKII peptide inhibitor. Eur J Med Chem 2013; 62:425-34. [PMID: 23395965 DOI: 10.1016/j.ejmech.2012.12.053] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2012] [Revised: 12/11/2012] [Accepted: 12/13/2012] [Indexed: 11/19/2022]
Abstract
Analogs of potent CaMKinase II inhibitor, CaM-KNtide, were prepared to explore new structural requirements for the inhibitory activity. The full potency of CaMKII inhibition by CaM-KIINα is contained within a minimal region of 19 amino acids. Here, analysis of the homologous CaM-KIINβ showed that a 17 mer peptide (CN17β) was the shortest sequence that still retained useful inhibitory potency. Ala substitution of almost any residue of CN17β dramatically reduced potency, except for substitution of P3, R14, and V16. Fusion with the tat sequence generated the cell-penetrating inhibitor version tat-5. This tat-5 fusion peptide maintained selectivity for CaMKII over CaMKI and CaMKIV, and appeared to slightly further enhance potency (IC50 ∼30 nM). Within a breast cancer cell line and in primary human fibroblasts, tat-5 inhibited the Erk signaling pathway and proliferation without any measurable cytotoxicity. Structural analysis of CN17β by CD and NMR indicated an α-helix conformation in the Leu6-Arg11 segment well overlapping with the crystal structure of 21-residue segment of CaM-KNtide bound to the kinase domain of CaMKII.
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Affiliation(s)
- Isabel Gomez-Monterrey
- Depart. of Pharmaceutical and Toxicological Chemistry, University of Naples Federico II, Naples, Italy
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A novel PKB/Akt inhibitor, MK-2206, effectively inhibits insulin-stimulated glucose metabolism and protein synthesis in isolated rat skeletal muscle. Biochem J 2012; 447:137-47. [PMID: 22793019 DOI: 10.1042/bj20120772] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
PKB (protein kinase B), also known as Akt, is a key component of insulin signalling. Defects in PKB activation lead to insulin resistance and metabolic disorders, whereas PKB overactivation has been linked to tumour growth. Small-molecule PKB inhibitors have thus been developed for cancer treatment, but also represent useful tools to probe the roles of PKB in insulin action. In the present study, we examined the acute effects of two allosteric PKB inhibitors, MK-2206 and Akti 1/2 (Akti) on PKB signalling in incubated rat soleus muscles. We also assessed the effects of the compounds on insulin-stimulated glucose uptake, glycogen and protein synthesis. MK-2206 dose-dependently inhibited insulin-stimulated PKB phosphorylation, PKBβ activity and phosphorylation of PKB downstream targets (including glycogen synthase kinase-3α/β, proline-rich Akt substrate of 40 kDa and Akt substrate of 160 kDa). Insulin-stimulated glucose uptake, glycogen synthesis and glycogen synthase activity were also decreased by MK-2206 in a dose-dependent manner. Incubation with high doses of MK-2206 (10 μM) inhibited insulin-induced p70 ribosomal protein S6 kinase and 4E-BP1 (eukaryotic initiation factor 4E-binding protein-1) phosphorylation associated with increased eEF2 (eukaryotic elongation factor 2) phosphorylation. In contrast, Akti only modestly inhibited insulin-induced PKB and mTOR (mammalian target of rapamycin) signalling, with little or no effect on glucose uptake and protein synthesis. MK-2206, rather than Akti, would thus be the tool of choice for studying the role of PKB in insulin action in skeletal muscle. The results point to a key role for PKB in mediating insulin-stimulated glucose uptake, glycogen synthesis and protein synthesis in skeletal muscle.
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46
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Beck-Nielsen H. The role of glycogen synthase in the development of hyperglycemia in type 2 diabetes: 'To store or not to store glucose, that's the question'. Diabetes Metab Res Rev 2012; 28:635-44. [PMID: 22926827 DOI: 10.1002/dmrr.2337] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
This review deals with the role of glycogen storage in skeletal muscle for the development of insulin resistance and type 2 diabetes. Specifically, the role of the enzyme glycogen synthase, which seems to be locked in its hyperphosphorylated and inactivated state, is discussed. This defect seems to be secondary to ectopic lipid disposition in the muscle cells. These molecular defects are discussed in the context of the overall pathophysiology of hyperglycemia in type 2 diabetic subjects.
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47
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Færch K, Højlund K, Vind BF, Vaag A, Dalgård C, Nielsen F, Grandjean P. Increased serum concentrations of persistent organic pollutants among prediabetic individuals: potential role of altered substrate oxidation patterns. J Clin Endocrinol Metab 2012; 97:E1705-13. [PMID: 22736774 PMCID: PMC3431564 DOI: 10.1210/jc.2012-1342] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/07/2012] [Accepted: 05/16/2012] [Indexed: 11/19/2022]
Abstract
CONTEXT There is a need for a better understanding of the potential role of persistent organic pollutants (POPs) in the pathogenesis of type 2 diabetes. OBJECTIVE Our objective was to determine the association of serum concentrations of POPs with early signs of type 2 diabetes in regard to glucose and lipid metabolism. RESEARCH DESIGN AND METHODS In this cross-sectional study, we used recent studies of 148 Danish middle-aged normoglycemic, prediabetic, and diabetic individuals examined by the euglycemic-hyperinsulinemic clamp technique with indirect calorimetry; 66 of these individuals also had an i.v. glucose tolerance test. Concentrations of POPs were analyzed in banked serum from the participants. Associations with basal and insulin-stimulated glucose and lipid metabolism were assessed after adjustment for age, sex, and body fat percentage. RESULTS Individuals with prediabetes and diabetes had higher serum concentrations of several POPs compared with normoglycemic individuals. In the nondiabetic population, higher POPs levels were associated with elevated fasting plasma glucose concentrations as well as reduced glucose oxidation, elevated lipid oxidation, and elevated serum concentrations of free fatty acids (P < 0.05). We found no associations of POPs with first-phase insulin secretion, hepatic or peripheral insulin sensitivity, or nonoxidative glucose metabolism. CONCLUSIONS Diabetic and prediabetic individuals have elevated serum concentrations of POPs. In nondiabetic individuals, POPs exposure is related to altered substrate oxidation patterns with lower glucose oxidation and higher lipid oxidation rates. These findings indicate that POPs may affect peripheral glucose metabolism by modifying pathways involved in substrate partitioning rather than decreasing insulin-dependent glucose uptake.
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Affiliation(s)
- Kristine Færch
- Steno Diabetes Center, Niels Steensens Vej 2, DK-2820 Gentofte, Denmark.
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Jensen J, Tantiwong P, Stuenæs JT, Molina-Carrion M, DeFronzo RA, Sakamoto K, Musi N. Effect of acute exercise on glycogen synthase in muscle from obese and diabetic subjects. Am J Physiol Endocrinol Metab 2012; 303:E82-9. [PMID: 22510711 PMCID: PMC3404561 DOI: 10.1152/ajpendo.00658.2011] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Insulin stimulates glycogen synthase (GS) through dephosphorylation of serine residues, and this effect is impaired in skeletal muscle from insulin-resistant [obese and type 2 diabetic (T2DM)] subjects. Exercise also increases GS activity, yet it is not known whether the ability of exercise to affect GS is impaired in insulin-resistant subjects. The objective of this study was to examine the effect of acute exercise on GS phosphorylation and enzyme kinetic properties in muscle from insulin-resistant individuals. Lean normal glucose-tolerant (NGT), obese NGT, and obese T2DM subjects performed 40 min of moderate-intensity cycle exercise (70% of Vo(2max)). GS kinetic properties and phosphorylation were measured in vastus lateralis muscle before exercise, immediately after exercise, and 3.5 h postexercise. In lean subjects, GS fractional activity increased twofold after 40 min of exercise, and it remained elevated after the 3.5-h rest period. Importantly, exercise also decreased GS K(m) for UDP-glucose from ≈0.5 to ≈0.2 mM. In lean subjects, exercise caused significant dephosphorylation of GS by 50-70% (Ser(641), Ser(645), and Ser(645,649,653,657)), and phosphorylation of these sites remained decreased after 3.5 h; Ser⁷ phosphorylation was not regulated by exercise. In obese NGT and T2DM subjects, exercise increased GS fractional activity, decreased K(m) for UDP-glucose, and decreased GS phosphorylation as effectively as in lean NGT subjects. We conclude that the molecular regulatory process by which exercise promotes glycogen synthesis in muscle is preserved in insulin-resistant subjects.
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Affiliation(s)
- Jørgen Jensen
- Department of Physical Performance, Norwegian School of Sport Sciences, Oslo, Norway
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49
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Vind BF, Birk JB, Vienberg SG, Andersen B, Beck-Nielsen H, Wojtaszewski JFP, Højlund K. Hyperglycaemia normalises insulin action on glucose metabolism but not the impaired activation of AKT and glycogen synthase in the skeletal muscle of patients with type 2 diabetes. Diabetologia 2012; 55:1435-45. [PMID: 22322917 DOI: 10.1007/s00125-012-2482-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2011] [Accepted: 01/09/2012] [Indexed: 10/14/2022]
Abstract
AIMS/HYPOTHESIS In type 2 diabetes, reduced insulin-stimulated glucose disposal, primarily glycogen synthesis, is associated with defective insulin activation of glycogen synthase (GS) in skeletal muscle. Hyperglycaemia may compensate for these defects, but to what extent it involves improved insulin signalling to glycogen synthesis remains to be clarified. METHODS Whole-body glucose metabolism was studied in 12 patients with type 2 diabetes, and 10 lean and 10 obese non-diabetic controls by means of indirect calorimetry and tracers during a euglycaemic-hyperinsulinaemic clamp. The diabetic patients underwent a second isoglycaemic-hyperinsulinaemic clamp maintaining fasting hyperglycaemia. Muscle biopsies from m. vastus lateralis were obtained before and after the clamp for examination of GS and relevant insulin signalling components. RESULTS During euglycaemia, insulin-stimulated glucose disposal, glucose oxidation and non-oxidative glucose metabolism were reduced in the diabetic group compared with both control groups (p < 0.05). This was associated with impaired insulin-stimulated GS and AKT2 activity, deficient dephosphorylation at GS sites 2 + 2a, and reduced Thr308 and Ser473 phosphorylation of AKT. When studied under hyperglycaemia, all variables of insulin-stimulated glucose metabolism were normalised compared with the weight-matched controls. However, insulin activation and dephosphorylation (site 2 + 2a) of GS as well as activation of AKT2 and phosphorylation at Thr308 and Ser473 remained impaired (p < 0.05). CONCLUSIONS/INTERPRETATIONS These data confirm that hyperglycaemia compensates for decreased whole-body glucose disposal in type 2 diabetes. In contrast to previous less well-controlled studies, we provide evidence that the compensatory effect of hyperglycaemia in patients with type 2 diabetes does not involve normalisation of insulin action on GS or upstream signalling in skeletal muscle.
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Affiliation(s)
- B F Vind
- Diabetes Research Centre, Department of Endocrinology, Odense University Hospital, DK-5000 Odense, Denmark
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50
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Biensø RS, Ringholm S, Kiilerich K, Aachmann-Andersen NJ, Krogh-Madsen R, Guerra B, Plomgaard P, van Hall G, Treebak JT, Saltin B, Lundby C, Calbet JAL, Pilegaard H, Wojtaszewski JFP. GLUT4 and glycogen synthase are key players in bed rest-induced insulin resistance. Diabetes 2012; 61:1090-9. [PMID: 22403297 PMCID: PMC3331744 DOI: 10.2337/db11-0884] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
To elucidate the molecular mechanisms behind physical inactivity-induced insulin resistance in skeletal muscle, 12 young, healthy male subjects completed 7 days of bed rest with vastus lateralis muscle biopsies obtained before and after. In six of the subjects, muscle biopsies were taken from both legs before and after a 3-h hyperinsulinemic euglycemic clamp performed 3 h after a 45-min, one-legged exercise. Blood samples were obtained from one femoral artery and both femoral veins before and during the clamp. Glucose infusion rate and leg glucose extraction during the clamp were lower after than before bed rest. This bed rest-induced insulin resistance occurred together with reduced muscle GLUT4, hexokinase II, protein kinase B/Akt1, and Akt2 protein level, and a tendency for reduced 3-hydroxyacyl-CoA dehydrogenase activity. The ability of insulin to phosphorylate Akt and activate glycogen synthase (GS) was reduced with normal GS site 3 but abnormal GS site 2+2a phosphorylation after bed rest. Exercise enhanced insulin-stimulated leg glucose extraction both before and after bed rest, which was accompanied by higher GS activity in the prior-exercised leg than the rested leg. The present findings demonstrate that physical inactivity-induced insulin resistance in muscle is associated with lower content/activity of key proteins in glucose transport/phosphorylation and storage.
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Affiliation(s)
- Rasmus S Biensø
- Copenhagen Muscle Research Centre, University of Copenhagen, Copenhagen, Denmark.
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