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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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Abstract
Growth hormone (GH) and insulin-like growth factor 1 (IGF-1) are essential to normal growth, metabolism, and body composition, but in acromegaly, excesses of these hormones strikingly alter them. In recent years, the use of modern methodologies to assess body composition in patients with acromegaly has revealed novel aspects of the acromegaly phenotype. In particular, acromegaly presents a unique pattern of body composition changes in the setting of insulin resistance that we propose herein to be considered an acromegaly-specific lipodystrophy. The lipodystrophy, initiated by a distinctive GH-driven adipose tissue dysregulation, features insulin resistance in the setting of reduced visceral adipose tissue (VAT) mass and intra-hepatic lipid (IHL) but with lipid redistribution, resulting in ectopic lipid deposition in muscle. With recovery of the lipodystrophy, adipose tissue mass, especially that of VAT and IHL, rises, but insulin resistance is lessened. Abnormalities of adipose tissue adipokines may play a role in the disordered adipose tissue metabolism and insulin resistance of the lipodystrophy. The orexigenic hormone ghrelin and peptide Agouti-related peptide may also be affected by active acromegaly as well as variably by acromegaly therapies, which may contribute to the lipodystrophy. Understanding the pathophysiology of the lipodystrophy and how acromegaly therapies differentially reverse its features may be important to optimizing the long-term outcome for patients with this disease. This perspective describes evidence in support of this acromegaly lipodystrophy model and its relevance to acromegaly pathophysiology and the treatment of patients with acromegaly.
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Affiliation(s)
- Pamela U. Freda
- Department of Medicine, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, United States
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3
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Large-Scale Functional Genomics Screen to Identify Modulators of Human β-Cell Insulin Secretion. Biomedicines 2022; 10:biomedicines10010103. [PMID: 35052782 PMCID: PMC8773179 DOI: 10.3390/biomedicines10010103] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Revised: 12/24/2021] [Accepted: 12/27/2021] [Indexed: 12/27/2022] Open
Abstract
Type 2 diabetes (T2D) is a chronic metabolic disorder affecting almost half a billion people worldwide. Impaired function of pancreatic β-cells is both a hallmark of T2D and an underlying factor in the pathophysiology of the disease. Understanding the cellular mechanisms regulating appropriate insulin secretion has been of long-standing interest in the scientific and clinical communities. To identify novel genes regulating insulin secretion we developed a robust arrayed siRNA screen measuring basal, glucose-stimulated, and augmented insulin secretion by EndoC-βH1 cells, a human β-cell line, in a 384-well plate format. We screened 521 candidate genes selected by text mining for relevance to T2D biology and identified 23 positive and 68 negative regulators of insulin secretion. Among these, we validated ghrelin receptor (GHSR), and two genes implicated in endoplasmic reticulum stress, ATF4 and HSPA5. Thus, we have demonstrated the feasibility of using EndoC-βH1 cells for large-scale siRNA screening to identify candidate genes regulating β-cell insulin secretion as potential novel drug targets. Furthermore, this screening format can be adapted to other disease-relevant functional endpoints to enable large-scale screening for targets regulating cellular mechanisms contributing to the progressive loss of functional β-cell mass occurring in T2D.
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Arlien-Søborg MC, Dal J, Madsen MA, Høgild ML, Hjelholt AJ, Pedersen SB, Møller N, Jessen N, Jørgensen JOL. Reversible insulin resistance in muscle and fat unrelated to the metabolic syndrome in patients with acromegaly. EBioMedicine 2021; 75:103763. [PMID: 34929488 PMCID: PMC8688588 DOI: 10.1016/j.ebiom.2021.103763] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Revised: 11/22/2021] [Accepted: 12/03/2021] [Indexed: 10/27/2022] Open
Abstract
BACKGROUND Patients with active acromegaly exhibit insulin resistance despite a lean phenotype whereas controlled disease improves insulin sensitivity and increases fat mass. The mechanisms underlying this paradox remain elusive, but growth hormone (GH)-induced lipolysis plays a central role. The aim of the study was to investigative the molecular mechanisms of insulin resistance dissociated from obesity in patients with acromegaly. METHODS In a prospective study, twenty-one patients with newly diagnosed acromegaly were studied at diagnosis and after disease control obtained by either surgery alone (n=10) or somatostatin analogue (SA) treatment (n=11) with assessment of body composition (DXA scan), whole body and tissue-specific insulin sensitivity and GH and insulin signalling in adipose tissue and skeletal muscle. FINDINGS Disease control of acromegaly significantly reduced lean body mass (p<0.001) and increased fat mass (p<0.001). At diagnosis, GH signalling (pSTAT5) was constitutively activated in fat and enhanced expression of GH-regulated genes (CISH and IGF-I) were detected in muscle and fat. Insulin sensitivity in skeletal muscle, liver and adipose tissue increased after disease control regardless of treatment modality. This was associated with enhanced insulin signalling in both muscle and fat including downregulation of phosphatase and tensin homolog (PTEN) together with reduced signalling of GH and lipolytic activators in fat. INTERPRETATION In conclusion, the study support that uncontrolled lipolysis is a major feature of insulin resistance in active acromegaly, and is characterized by upregulation of PTEN and suppression of insulin signalling in both muscle and fat. FUNDING This work was supported by a grant from the Independent Research Fund, Denmark (7016-00303A) and from the Alfred Benzon Foundation, Denmark.
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Affiliation(s)
- Mai C Arlien-Søborg
- Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Denmark; Medical Research Laboratory, Department of Clinical Medicine, Aarhus University Hospital, Denmark.
| | - Jakob Dal
- Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Denmark; Department of Endocrinology, Aalborg University Hospital, Denmark; Steno Diabetes Centre North, Aalborg University Hospital, Aalborg, Denmark
| | - Michael Alle Madsen
- Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Denmark; Department of Nuclear Medicine & PET Centre, Aarhus University Hospital, Denmark
| | - Morten Lyng Høgild
- Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Denmark; Medical Research Laboratory, Department of Clinical Medicine, Aarhus University Hospital, Denmark
| | - Astrid Johannesson Hjelholt
- Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Denmark; Medical Research Laboratory, Department of Clinical Medicine, Aarhus University Hospital, Denmark
| | | | - Niels Møller
- Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Denmark; Medical Research Laboratory, Department of Clinical Medicine, Aarhus University Hospital, Denmark
| | - Niels Jessen
- Steno Diabetes Centre, Aarhus, Denmark; Department of Clinical Pharmacology, University of Aarhus, Aarhus, Denmark; Department of Biomedicine, Aarhus University, Denmark
| | - Jens O L Jørgensen
- Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Denmark; Medical Research Laboratory, Department of Clinical Medicine, Aarhus University Hospital, Denmark
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Towards Understanding the Direct and Indirect Actions of Growth Hormone in Controlling Hepatocyte Carbohydrate and Lipid Metabolism. Cells 2021; 10:cells10102532. [PMID: 34685512 PMCID: PMC8533955 DOI: 10.3390/cells10102532] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 09/20/2021] [Accepted: 09/23/2021] [Indexed: 02/06/2023] Open
Abstract
Growth hormone (GH) is critical for achieving normal structural growth. In addition, GH plays an important role in regulating metabolic function. GH acts through its GH receptor (GHR) to modulate the production and function of insulin-like growth factor 1 (IGF1) and insulin. GH, IGF1, and insulin act on multiple tissues to coordinate metabolic control in a context-specific manner. This review will specifically focus on our current understanding of the direct and indirect actions of GH to control liver (hepatocyte) carbohydrate and lipid metabolism in the context of normal fasting (sleep) and feeding (wake) cycles and in response to prolonged nutrient deprivation and excess. Caveats and challenges related to the model systems used and areas that require further investigation towards a clearer understanding of the role GH plays in metabolic health and disease are discussed.
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Wali JA, Solon-Biet SM, Freire T, Brandon AE. Macronutrient Determinants of Obesity, Insulin Resistance and Metabolic Health. BIOLOGY 2021; 10:336. [PMID: 33923531 PMCID: PMC8072595 DOI: 10.3390/biology10040336] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Accepted: 04/07/2021] [Indexed: 01/18/2023]
Abstract
Obesity caused by the overconsumption of calories has increased to epidemic proportions. Insulin resistance is often associated with an increased adiposity and is a precipitating factor in the development of cardiovascular disease, type 2 diabetes, and altered metabolic health. Of the various factors contributing to metabolic impairments, nutrition is the major modifiable factor that can be targeted to counter the rising prevalence of obesity and metabolic diseases. However, the macronutrient composition of a nutritionally balanced "healthy diet" are unclear, and so far, no tested dietary intervention has been successful in achieving long-term compliance and reductions in body weight and associated beneficial health outcomes. In the current review, we briefly describe the role of the three major macronutrients, carbohydrates, fats, and proteins, and their role in metabolic health, and provide mechanistic insights. We also discuss how an integrated multi-dimensional approach to nutritional science could help in reconciling apparently conflicting findings.
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Affiliation(s)
- Jibran A. Wali
- Charles Perkins Centre, University of Sydney, Sydney, NSW 2006, Australia; (J.A.W.); (S.M.S.-B.); (T.F.)
- School of Life and Environmental Sciences, Faculty of Science, University of Sydney, Sydney, NSW 2006, Australia
| | - Samantha M. Solon-Biet
- Charles Perkins Centre, University of Sydney, Sydney, NSW 2006, Australia; (J.A.W.); (S.M.S.-B.); (T.F.)
- School of Medical Sciences, Faculty of Medicine and Health, University of Sydney, Sydney, NSW 2006, Australia
| | - Therese Freire
- Charles Perkins Centre, University of Sydney, Sydney, NSW 2006, Australia; (J.A.W.); (S.M.S.-B.); (T.F.)
- School of Medical Sciences, Faculty of Medicine and Health, University of Sydney, Sydney, NSW 2006, Australia
| | - Amanda E. Brandon
- Charles Perkins Centre, University of Sydney, Sydney, NSW 2006, Australia; (J.A.W.); (S.M.S.-B.); (T.F.)
- School of Medical Sciences, Faculty of Medicine and Health, University of Sydney, Sydney, NSW 2006, Australia
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Pyruvate dehydrogenase kinases (PDKs): an overview toward clinical applications. Biosci Rep 2021; 41:228121. [PMID: 33739396 PMCID: PMC8026821 DOI: 10.1042/bsr20204402] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 03/12/2021] [Accepted: 03/17/2021] [Indexed: 01/01/2023] Open
Abstract
Pyruvate dehydrogenase kinase (PDK) can regulate the catalytic activity of pyruvate decarboxylation oxidation via the mitochondrial pyruvate dehydrogenase complex, and it further links glycolysis with the tricarboxylic acid cycle and ATP generation. This review seeks to elucidate the regulation of PDK activity in different species, mainly mammals, and the role of PDK inhibitors in preventing increased blood glucose, reducing injury caused by myocardial ischemia, and inducing apoptosis of tumor cells. Regulations of PDKs expression or activity represent a very promising approach for treatment of metabolic diseases including diabetes, heart failure, and cancer. The future research and development could be more focused on the biochemical understanding of the diseases, which would help understand the cellular energy metabolism and its regulation by pharmacological effectors of PDKs.
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Sharma R, Kopchick JJ, Puri V, Sharma VM. Effect of growth hormone on insulin signaling. Mol Cell Endocrinol 2020; 518:111038. [PMID: 32966863 PMCID: PMC7606590 DOI: 10.1016/j.mce.2020.111038] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 08/31/2020] [Accepted: 09/17/2020] [Indexed: 12/21/2022]
Abstract
Growth hormone (GH) is a pleiotropic hormone that coordinates an array of physiological processes, including effects on bone, muscle, and fat, ultimately resulting in growth. Metabolically, GH promotes anabolic action in most tissues except adipose, where its catabolic action causes the breakdown of stored triglycerides into free fatty acids (FFA). GH antagonizes insulin action via various molecular pathways. Chronic GH secretion suppresses the anti-lipolytic action of insulin and increases FFA flux into the systemic circulation; thus, promoting lipotoxicity, which causes pathophysiological problems, including insulin resistance. In this review, we will provide an update on GH-stimulated adipose lipolysis and its consequences on insulin signaling in liver, skeletal muscle, and adipose tissue. Furthermore, we will discuss the mechanisms that contribute to the diabetogenic action of GH.
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Affiliation(s)
- Rita Sharma
- Department of Biomedical Sciences, Ohio University, Athens, OH, 45701, USA
| | - John J Kopchick
- Department of Biomedical Sciences, Ohio University, Athens, OH, 45701, USA; Edison Biotechnology Institute, Ohio University, Athens, OH, 45701, USA; Diabetes Institute, Ohio University, Athens, OH, 45701, USA
| | - Vishwajeet Puri
- Department of Biomedical Sciences, Ohio University, Athens, OH, 45701, USA; Diabetes Institute, Ohio University, Athens, OH, 45701, USA
| | - Vishva M Sharma
- Department of Biomedical Sciences, Ohio University, Athens, OH, 45701, USA; Diabetes Institute, Ohio University, Athens, OH, 45701, USA.
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Hjelholt AJ, Charidemou E, Griffin JL, Pedersen SB, Gudiksen A, Pilegaard H, Jessen N, Møller N, Jørgensen JOL. Insulin resistance induced by growth hormone is linked to lipolysis and associated with suppressed pyruvate dehydrogenase activity in skeletal muscle: a 2 × 2 factorial, randomised, crossover study in human individuals. Diabetologia 2020; 63:2641-2653. [PMID: 32945898 DOI: 10.1007/s00125-020-05262-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Accepted: 07/15/2020] [Indexed: 02/07/2023]
Abstract
AIMS/HYPOTHESIS Growth hormone (GH) causes insulin resistance that is linked to lipolysis, but the underlying mechanisms are unclear. We investigated if GH-induced insulin resistance in skeletal muscle involves accumulation of diacylglycerol (DAG) and ceramide as well as impaired insulin signalling, or substrate competition between fatty acids and glucose. METHODS Nine GH-deficient male participants were randomised and examined in a 2 × 2 factorial design with and without administration of GH and acipimox (an anti-lipolytic compound). As-treated analyses were performed, wherefore data from three visits from two patients were excluded due to incorrect GH administration. The primary outcome was insulin sensitivity, expressed as the AUC of the glucose infusion rate (GIRAUC), and furthermore, the levels of DAGs and ceramides, insulin signalling and the activity of the active form of pyruvate dehydrogenase (PDHa) were assessed in skeletal muscle biopsies obtained in the basal state and during a hyperinsulinaemic-euglycaemic clamp (HEC). RESULTS Co-administration of acipimox completely suppressed the GH-induced elevation in serum levels of NEFA (GH versus GH+acipimox, p < 0.0001) and abrogated GH-induced insulin resistance (mean GIRAUC [95% CI] [mg min-1 kg-1] during the HEC: control, 595 [493, 718]; GH, 468 [382, 573]; GH+acipimox, 654 [539, 794]; acipimox, 754 [618, 921]; GH vs GH+acipimox: p = 0.004). GH did not significantly change either the accumulation of DAGs and ceramides or insulin signalling in skeletal muscle, but GH antagonised the insulin-stimulated increase in PDHa activity (mean ± SEM [% from the basal state to the HEC]: control, 47 ± 19; GH, -15 ± 21; GH+acipimox, 3 ± 21; acipimox, 57 ± 22; main effect: p = 0.02). CONCLUSIONS/INTERPRETATION GH-induced insulin resistance in skeletal muscle is: (1) causally linked to lipolysis; (2) not associated with either accumulation of DAGs and ceramides or impaired insulin signalling; (3) likely to involve substrate competition between glucose and lipid intermediates. TRIAL REGISTRATION ClinicalTrials.gov NCT02782208 FUNDING: The work was supported by the Grant for Growth Innovation (GGI), which was funded by Merck KGaA, Darmstadt, Germany. Graphical abstract.
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Affiliation(s)
- Astrid J Hjelholt
- Medical Research Laboratory, Department of Clinical Medicine, Endocrinology and Internal Medicine, Aarhus University Hospital, Aarhus N, Denmark.
- Department of Clinical Pharmacology, Aarhus University Hospital, Aarhus C, Denmark.
| | - Evelina Charidemou
- Department of Biochemistry and Cambridge Systems Biology Centre, University of Cambridge, Cambridge, UK
| | - Julian L Griffin
- Department of Biochemistry and Cambridge Systems Biology Centre, University of Cambridge, Cambridge, UK
| | - Steen B Pedersen
- Medical Research Laboratory, Department of Clinical Medicine, Endocrinology and Internal Medicine, Aarhus University Hospital, Aarhus N, Denmark
| | - Anders Gudiksen
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Henriette Pilegaard
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Niels Jessen
- Department of Clinical Pharmacology, Aarhus University Hospital, Aarhus C, Denmark
- Steno Diabetes Centre Aarhus, Aarhus University Hospital, Aarhus N, Denmark
- Department of Biomedicine, Aarhus University, Aarhus C, Denmark
| | - Niels Møller
- Medical Research Laboratory, Department of Clinical Medicine, Endocrinology and Internal Medicine, Aarhus University Hospital, Aarhus N, Denmark
| | - Jens O L Jørgensen
- Medical Research Laboratory, Department of Clinical Medicine, Endocrinology and Internal Medicine, Aarhus University Hospital, Aarhus N, Denmark
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10
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Høgild ML, Gudiksen A, Pilegaard H, Stødkilde-Jørgensen H, Pedersen SB, Møller N, Jørgensen JOL, Jessen N. Redundancy in regulation of lipid accumulation in skeletal muscle during prolonged fasting in obese men. Physiol Rep 2020; 7:e14285. [PMID: 31724339 PMCID: PMC6854099 DOI: 10.14814/phy2.14285] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Fasting in human subjects shifts skeletal muscle metabolism toward lipid utilization and accumulation, including intramyocellular lipid (IMCL) deposition. Growth hormone (GH) secretion amplifies during fasting and promotes lipolysis and lipid oxidation, but it is unknown to which degree lipid deposition and metabolism in skeletal muscle during fasting depends on GH action. To test this, we studied nine obese but otherwise healthy men thrice: (a) in the postabsorptive state (“CTRL”), (b) during 72‐hr fasting (“FAST”), and (c) during 72‐hr fasting and treatment with a GH antagonist (GHA) (“FAST + GHA”). IMCL was assessed by magnetic resonance spectroscopy (MRS) and blood samples were drawn for plasma metabolomics assessment while muscle biopsies were obtained for measurements of regulators of substrate metabolism. Prolonged fasting was associated with elevated GH levels and a pronounced GHA‐independent increase in circulating medium‐ and long‐chain fatty acids, glycerol, and ketone bodies indicating increased supply of lipid intermediates to skeletal muscle. Additionally, fasting was associated with a release of short‐, medium‐, and long‐chain acylcarnitines to the circulation from an increased β‐oxidation. This was consistent with a ≈55%–60% decrease in pyruvate dehydrogenase (PDHa) activity. Opposite, IMCL content increased ≈75% with prolonged fasting without an effect of GHA. We suggest that prolonged fasting increases lipid uptake in skeletal muscle and saturates lipid oxidation, both favoring IMCL deposition. This occurs without a detectable effect of GHA on skeletal muscle lipid metabolism.
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Affiliation(s)
- Morten L Høgild
- Medical Research Laboratory, Department of Clinical Medicine, Aarhus University Hospital, Aarhus, Denmark.,Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Anders Gudiksen
- Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | | | - Hans Stødkilde-Jørgensen
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark.,The MR Research Center, Aarhus University Hospital, Copenhagen, Denmark
| | - Steen Bønløkke Pedersen
- Medical Research Laboratory, Department of Clinical Medicine, Aarhus University Hospital, Aarhus, Denmark.,Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Niels Møller
- Medical Research Laboratory, Department of Clinical Medicine, Aarhus University Hospital, Aarhus, Denmark.,Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Jens O L Jørgensen
- Medical Research Laboratory, Department of Clinical Medicine, Aarhus University Hospital, Aarhus, Denmark.,Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Niels Jessen
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark.,Department of Clinical Pharmacology, Aarhus University Hospital, Aarhus, Denmark.,Department of Biomedicine, Aarhus University, Aarhus, Denmark
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11
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Kopchick JJ, Berryman DE, Puri V, Lee KY, Jorgensen JOL. The effects of growth hormone on adipose tissue: old observations, new mechanisms. Nat Rev Endocrinol 2020; 16:135-146. [PMID: 31780780 PMCID: PMC7180987 DOI: 10.1038/s41574-019-0280-9] [Citation(s) in RCA: 72] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 10/16/2019] [Indexed: 12/18/2022]
Abstract
The ability of growth hormone (GH) to induce adipose tissue lipolysis has been known for over five decades; however, the molecular mechanisms that mediate this effect and the ability of GH to inhibit insulin-stimulated glucose uptake have scarcely been documented. In this same time frame, our understanding of adipose tissue has evolved to reveal a complex structure with distinct types of adipocyte, depot-specific differences, a biologically significant extracellular matrix and important endocrine properties mediated by adipokines. All these aforementioned features, in turn, can influence lipolysis. In this Review, we provide a historical and current overview of the lipolytic effect of GH in humans, mice and cultured cells. More globally, we explain lipolysis in terms of GH-induced intracellular signalling and its effect on obesity, insulin resistance and lipotoxicity. In this regard, findings that define molecular mechanisms by which GH induces lipolysis are described. Finally, data are presented for the differential effect of GH on specific adipose tissue depots and on distinct classes of metabolically active adipocytes. Together, these cellular, animal and human studies reveal novel cellular phenotypes and molecular pathways regulating the metabolic effects of GH on adipose tissue.
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Affiliation(s)
- John J Kopchick
- Edison Biotechnology Institute, Ohio University, Athens, OH, USA.
- The Diabetes Institute, Ohio University Heritage College of Osteopathic Medicine, Athens, OH, USA.
- Department of Biomedical Sciences, Ohio University College of Osteopathic Medicine, Athens, OH, USA.
| | - Darlene E Berryman
- Edison Biotechnology Institute, Ohio University, Athens, OH, USA
- The Diabetes Institute, Ohio University Heritage College of Osteopathic Medicine, Athens, OH, USA
- Department of Biomedical Sciences, Ohio University College of Osteopathic Medicine, Athens, OH, USA
| | - Vishwajeet Puri
- The Diabetes Institute, Ohio University Heritage College of Osteopathic Medicine, Athens, OH, USA
- Department of Biomedical Sciences, Ohio University College of Osteopathic Medicine, Athens, OH, USA
| | - Kevin Y Lee
- The Diabetes Institute, Ohio University Heritage College of Osteopathic Medicine, Athens, OH, USA
- Department of Biomedical Sciences, Ohio University College of Osteopathic Medicine, Athens, OH, USA
| | - Jens O L Jorgensen
- Department of Endocrinology and Diabetes, Aarhus University Hospital, Aarhus, Denmark
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12
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Hjelholt AJ, Lee KY, Arlien-Søborg MC, Pedersen SB, Kopchick JJ, Puri V, Jessen N, Jørgensen JOL. Temporal patterns of lipolytic regulators in adipose tissue after acute growth hormone exposure in human subjects: A randomized controlled crossover trial. Mol Metab 2019; 29:65-75. [PMID: 31668393 PMCID: PMC6731350 DOI: 10.1016/j.molmet.2019.08.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Revised: 08/11/2019] [Accepted: 08/15/2019] [Indexed: 12/18/2022] Open
Abstract
Objective Growth hormone (GH) stimulates lipolysis, but the underlying mechanisms remain incompletely understood. We examined the effect of GH on the expression of lipolytic regulators in adipose tissue (AT). Methods In a randomized, placebo-controlled, cross-over study, nine men were examined after injection of 1) a GH bolus and 2) a GH-receptor antagonist (pegvisomant) followed by four AT biopsies. In a second study, eight men were examined in a 2 × 2 factorial design including GH infusion and 36-h fasting with AT biopsies obtained during a basal period and a hyperinsulinemic-euglycemic clamp. Expression of GH-signaling intermediates and lipolytic regulators were studied by PCR and western blotting. In addition, mechanistic experiments in mouse models and 3T3-L1 adipocytes were performed. Results The GH bolus increased circulating free fatty acids (p < 0.0001) together with phosphorylation of signal transducer and activator of transcription 5 (STAT5) (p < 0.0001) and mRNA expression of the STAT5-dependent genes cytokine-inducible SH2-containing protein (CISH) and IGF-1 in AT. This was accompanied by suppressed mRNA expression of G0/G1 switch gene 2 (G0S2) (p = 0.007) and fat specific protein 27 (FSP27) (p = 0.002) and upregulation of phosphatase and tensin homolog (PTEN) mRNA expression (p = 0.03). Suppression of G0S2 was also observed in humans after GH infusion and fasting, as well as in GH transgene mice, and in vitro studies suggested MEK-PPARγ signaling to be involved. Conclusions GH-induced lipolysis in human subjects in vivo is linked to downregulation of G0S2 and FSP27 and upregulation of PTEN in AT. Mechanistically, in vitro data suggest that GH acts via MEK to suppress PPARγ-dependent transcription of G0S2. ClinicalTrials.govNCT02782221 and NCT01209429. Acute GH exposure in human subjects in vivo stimulates lipolysis and release of FFA together with GH signaling in adipose tissue. GH-induced lipolysis is associated with suppression of G0S2 and FSP27 and upregulation of PTEN in human subjects in vivo. Inhibition of MEK and activation of PPARγ abrogate GH-induced suppression of G0S2 mRNA expression in vitro.
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Affiliation(s)
- Astrid Johannesson Hjelholt
- Medical Research Laboratory, Department of Clinical Medicine, Endocrinology and Internal Medicine, Aarhus University Hospital, Palle Juul-Jensens Boulevard 165, 8200 Aarhus N, Denmark; Department of Clinical Medicine, Aarhus University, Palle Juul-Jensens Boulevard 82, 8200 Aarhus N, Denmark.
| | - Kevin Y Lee
- Heritage College of Osteopathic Medicine, Ohio University, 204 Grosvenor Hall, Athens, OH 45701, USA; The Diabetes Institute, Ohio University, Konneker Research Center 108, Athens, OH 45701, USA
| | - Mai Christiansen Arlien-Søborg
- Medical Research Laboratory, Department of Clinical Medicine, Endocrinology and Internal Medicine, Aarhus University Hospital, Palle Juul-Jensens Boulevard 165, 8200 Aarhus N, Denmark; Department of Clinical Medicine, Aarhus University, Palle Juul-Jensens Boulevard 82, 8200 Aarhus N, Denmark
| | - Steen Bønløkke Pedersen
- Medical Research Laboratory, Department of Clinical Medicine, Endocrinology and Internal Medicine, Aarhus University Hospital, Palle Juul-Jensens Boulevard 165, 8200 Aarhus N, Denmark; Steno Diabetes Center Aarhus, Aarhus University Hospital, Hedeager 3, 2., 8200 Aarhus N, Denmark
| | - John J Kopchick
- Heritage College of Osteopathic Medicine, Ohio University, 204 Grosvenor Hall, Athens, OH 45701, USA; The Edison Biotechnology Institute, Ohio University, Konneker Research Center, 172 Water Tower Dr., Athens, OH 45701, USA
| | - Vishwajeet Puri
- Heritage College of Osteopathic Medicine, Ohio University, 204 Grosvenor Hall, Athens, OH 45701, USA; The Diabetes Institute, Ohio University, Konneker Research Center 108, Athens, OH 45701, USA
| | - Niels Jessen
- Steno Diabetes Center Aarhus, Aarhus University Hospital, Hedeager 3, 2., 8200 Aarhus N, Denmark; Department of Clinical Pharmacology, Aarhus University Hospital, Wilh. Meyers Allé 4, 8000 Aarhus C, Denmark; Department of Biomedicine, Aarhus University, Vennelyst Boulevard 4, 8000 Aarhus C, Denmark
| | - Jens Otto L Jørgensen
- Medical Research Laboratory, Department of Clinical Medicine, Endocrinology and Internal Medicine, Aarhus University Hospital, Palle Juul-Jensens Boulevard 165, 8200 Aarhus N, Denmark; Department of Clinical Medicine, Aarhus University, Palle Juul-Jensens Boulevard 82, 8200 Aarhus N, Denmark
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13
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Chhabra Y, Nelson CN, Plescher M, Barclay JL, Smith AG, Andrikopoulos S, Mangiafico S, Waxman DJ, Brooks AJ, Waters MJ. Loss of growth hormone-mediated signal transducer and activator of transcription 5 (STAT5) signaling in mice results in insulin sensitivity with obesity. FASEB J 2019; 33:6412-6430. [PMID: 30779881 PMCID: PMC6463913 DOI: 10.1096/fj.201802328r] [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] [Indexed: 02/04/2023]
Abstract
Growth hormone (GH) has an important function as an insulin antagonist with elevated insulin sensitivity evident in humans and mice lacking a functional GH receptor (GHR). We sought the molecular basis for this sensitivity by utilizing a panel of mice possessing specific deletions of GHR signaling pathways. Metabolic clamps and glucose homeostasis tests were undertaken in these obese adult C57BL/6 male mice, which indicated impaired hepatic gluconeogenesis. Insulin sensitivity and glucose disappearance rate were enhanced in muscle and adipose of mice lacking the ability to activate the signal transducer and activator of transcription (STAT)5 via the GHR (Ghr-391-/-) as for GHR-null (GHR-/-) mice. These changes were associated with a striking inhibition of hepatic glucose output associated with altered glycogen metabolism and elevated hepatic glycogen content during unfed state. The enhanced hepatic insulin sensitivity was associated with increased insulin receptor β and insulin receptor substrate 1 activation along with activated downstream protein kinase B signaling cascades. Although phosphoenolpyruvate carboxykinase (Pck)-1 expression was unchanged, its inhibitory acetylation was elevated because of decreased sirtuin-2 expression, thereby promoting loss of PCK1. Loss of STAT5 signaling to defined chromatin immunoprecipitation targets would further increase lipogenesis, supporting hepatosteatosis while lowering glucose output. Finally, up-regulation of IL-15 expression in muscle, with increased secretion of adiponectin and fibroblast growth factor 1 from adipose tissue, is expected to promote insulin sensitivity.-Chhabra, Y., Nelson, C. N., Plescher, M., Barclay, J. L., Smith, A. G., Andrikopoulos, S., Mangiafico, S., Waxman, D. J., Brooks, A. J., Waters, M. J. Loss of growth hormone-mediated signal transducer and activator of transcription 5 (STAT5) signaling in mice results in insulin sensitivity with obesity.
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Affiliation(s)
- Yash Chhabra
- University of Queensland Diamantina Institute, The University of Queensland, Translational Research Institute, Brisbane, Queensland, Australia.,Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Caroline N Nelson
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Monika Plescher
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia.,Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, Bonn, Germany
| | - Johanna L Barclay
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia.,Mater Research Institute, The University of Queensland, Translational Research Institute, Brisbane, Queensland, Australia
| | - Aaron G Smith
- School of Biomedical Sciences, Institute of Health and Biomedical Innovation, The University of Queensland, Translational Research Institute, Brisbane, Queensland, Australia
| | - Sof Andrikopoulos
- Department of Medicine, The University of Melbourne, Victoria, Australia
| | | | - David J Waxman
- Department of Biology and Bioinformatics Program, Boston University, Boston, Massachusetts, USA
| | - Andrew J Brooks
- University of Queensland Diamantina Institute, The University of Queensland, Translational Research Institute, Brisbane, Queensland, Australia.,Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Michael J Waters
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
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14
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Lu M, Flanagan JU, Langley RJ, Hay MP, Perry JK. Targeting growth hormone function: strategies and therapeutic applications. Signal Transduct Target Ther 2019; 4:3. [PMID: 30775002 PMCID: PMC6367471 DOI: 10.1038/s41392-019-0036-y] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Revised: 12/10/2018] [Accepted: 12/12/2018] [Indexed: 01/12/2023] Open
Abstract
Human growth hormone (GH) is a classical pituitary endocrine hormone that is essential for normal postnatal growth and has pleiotropic effects across multiple physiological systems. GH is also expressed in extrapituitary tissues and has localized autocrine/paracrine effects at these sites. In adults, hypersecretion of GH causes acromegaly, and strategies that block the release of GH or that inhibit GH receptor (GHR) activation are the primary forms of medical therapy for this disease. Overproduction of GH has also been linked to cancer and the microvascular complications that are associated with diabetes. However, studies to investigate the therapeutic potential of GHR antagonism in these diseases have been limited, most likely due to difficulty in accessing therapeutic tools to study the pharmacology of the receptor in vivo. This review will discuss current and emerging strategies for antagonizing GH function and the potential disease indications. Emerging therapies are offering an expanded toolkit for combatting the effects of human growth hormone overproduction. Human growth hormone (GH) is a major driver of postnatal growth; however, systemic or localized overproduction is implicated in the aberrant growth disease acromegaly, cancer, and diabetes. In this review, researchers led by Jo Perry, from the University of Auckland, New Zealand, discuss strategies that either inhibit GH production, block its systemic receptor, or interrupt its downstream signaling pathways. The only licensed GH receptor blocker is pegvisomant, but therapies are in development that include long-acting protein and antibody-based blockers, and nucleotide complexes that degrade GHR production have also shown promise. Studies investigating GHR antagonism are limited, partly due to difficulty in accessing therapeutic tools which block GHR function, but overcoming these obstacles may yield advances in alleviating chronic disease.
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Affiliation(s)
- Man Lu
- 1Liggins Institute, University of Auckland, Auckland, New Zealand
| | - Jack U Flanagan
- 2Auckland Cancer Society Research Centre, School of Medical Sciences, University of Auckland, Auckland, New Zealand.,3Maurice Wilkins Centre for Molecular Biodiscovery, Auckland, New Zealand
| | - Ries J Langley
- 3Maurice Wilkins Centre for Molecular Biodiscovery, Auckland, New Zealand.,4Department of Molecular Medicine and Pathology, School of Medical Sciences, University of Auckland, Auckland, New Zealand
| | - Michael P Hay
- 2Auckland Cancer Society Research Centre, School of Medical Sciences, University of Auckland, Auckland, New Zealand.,3Maurice Wilkins Centre for Molecular Biodiscovery, Auckland, New Zealand
| | - Jo K Perry
- 1Liggins Institute, University of Auckland, Auckland, New Zealand.,3Maurice Wilkins Centre for Molecular Biodiscovery, Auckland, New Zealand
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15
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Høgild ML, Bak AM, Pedersen SB, Rungby J, Frystyk J, Møller N, Jessen N, Jørgensen JOL. Growth hormone signaling and action in obese versus lean human subjects. Am J Physiol Endocrinol Metab 2019; 316:E333-E344. [PMID: 30576246 DOI: 10.1152/ajpendo.00431.2018] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Growth hormone (GH) levels are blunted in obesity, but it is not known whether this relates to altered GH sensitivity and whether this influences the metabolic adaptation to fasting. Therefore, we investigated the effect of obesity on GH signal transduction and fasting-induced changes in GH action. Nine obese (BMI 35.7 kg/m2) and nine lean (BMI 21.5 kg/m2) men were studied in a randomized crossover design with 1) an intravenous GH bolus, 2) an intravenous saline bolus, and 3) 72 h of fasting. Insulin sensitivity (hyperinsulinemic, euglycemic clamp) and substrate metabolism (glucose tracer and indirect calorimetry) were measured in studies 1 and 2. In vivo GH signaling was assessed in muscle and fat biopsies. GH pharmacokinetics did not differ between obese and lean subjects, but endogenous GH levels were reduced in obesity. GH signaling (STAT5b phosphorylation and CISH mRNA transcription), and GH action (induction of lipolysis and peripheral insulin resistance) were similar in the two groups, but a GH-induced insulin antagonistic effect on endogenous glucose production only occurred in the obese. Fasting-induced IGF-I reduction was completely abrogated in obese subjects despite a comparable relative increase in GH levels (ΔIGF-I: lean, -66 ± 10 vs. obese, 27 ± 16 µg/l; P < 0.01; ΔGH: lean, 647 ± 280 vs. obese, 544 ± 220%; P = 0.76]. We conclude that 1) GH signaling is normal in obesity, 2) in the obese state, the preservation of IGF-I with fasting and the augmented GH-induced central insulin resistance indicate increased hepatic GH sensitivity, 3) blunted GH levels in obesity may protect against insulin resistance without compromising IGF-I status.
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Affiliation(s)
- Morten Lyng Høgild
- Medical Research Laboratory, Department of Clinical Medicine, Aarhus University Hospital , Denmark
- Department of Clinical Medicine, Aarhus University , Denmark
| | - Ann Mosegaard Bak
- Medical Research Laboratory, Department of Clinical Medicine, Aarhus University Hospital , Denmark
- Department of Clinical Medicine, Aarhus University , Denmark
| | - Steen Bønløkke Pedersen
- Medical Research Laboratory, Department of Clinical Medicine, Aarhus University Hospital , Denmark
- Department of Clinical Medicine, Aarhus University , Denmark
| | - Jørgen Rungby
- Department of Biomedicine, Aarhus University , Denmark
| | - Jan Frystyk
- Medical Research Laboratory, Department of Clinical Medicine, Aarhus University Hospital , Denmark
- Department of Clinical Medicine, Aarhus University , Denmark
| | - Niels Møller
- Medical Research Laboratory, Department of Clinical Medicine, Aarhus University Hospital , Denmark
- Department of Clinical Medicine, Aarhus University , Denmark
| | - Niels Jessen
- Department of Clinical Medicine, Aarhus University , Denmark
- Department of Biomedicine, Aarhus University , Denmark
- Department of Clinical Pharmacology, Aarhus University Hospital , Denmark
| | - Jens O L Jørgensen
- Medical Research Laboratory, Department of Clinical Medicine, Aarhus University Hospital , Denmark
- Department of Clinical Medicine, Aarhus University , Denmark
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16
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Vila G, Jørgensen JOL, Luger A, Stalla GK. Insulin Resistance in Patients With Acromegaly. Front Endocrinol (Lausanne) 2019; 10:509. [PMID: 31417493 PMCID: PMC6683662 DOI: 10.3389/fendo.2019.00509] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2019] [Accepted: 07/12/2019] [Indexed: 12/20/2022] Open
Abstract
Acromegaly is characterized by chronic overproduction of growth hormone (GH) that leads to insulin resistance, glucose intolerance and, ultimately, diabetes. The GH-induced sustained stimulation of lipolysis plays a major role not only in the development of insulin resistance and prediabetes/diabetes, but also in the reduction of lipid accumulation, making acromegaly a unique case of severe insulin resistance in the presence of reduced body fat. In the present review, we elucidate the effects of GH hypersecretion on metabolic organs, describing the pathophysiology of impaired glucose tolerance in acromegaly, as well as the impact of acromegaly-specific therapies on glucose metabolism. In addition, we highlight the role of insulin resistance in the development of acromegaly-associated complications such as hypertension, cardiac disease, sleep apnea, polycystic ovaries, bone disease, and cancer. Taken together, insulin resistance is an important metabolic hallmark of acromegaly, which is strongly related to disease activity, the development of comorbidities, and might even impact the response to drugs used in the treatment of acromegaly.
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Affiliation(s)
- Greisa Vila
- Division of Endocrinology and Metabolism, Department of Internal Medicine III, Medical University of Vienna, Vienna, Austria
| | - Jens Otto L. Jørgensen
- Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Aarhus, Denmark
| | - Anton Luger
- Division of Endocrinology and Metabolism, Department of Internal Medicine III, Medical University of Vienna, Vienna, Austria
| | - Günter K. Stalla
- Max Planck Institute of Psychiatry, Munich, Germany
- *Correspondence: Günter K. Stalla ;
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17
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Sharma VM, Vestergaard ET, Jessen N, Kolind-Thomsen P, Nellemann B, Nielsen TS, Vendelbo MH, Møller N, Sharma R, Lee KY, Kopchick JJ, Jørgensen JOL, Puri V. Growth hormone acts along the PPARγ-FSP27 axis to stimulate lipolysis in human adipocytes. Am J Physiol Endocrinol Metab 2019; 316:E34-E42. [PMID: 30325658 PMCID: PMC6417689 DOI: 10.1152/ajpendo.00129.2018] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Revised: 10/01/2018] [Accepted: 10/03/2018] [Indexed: 12/22/2022]
Abstract
The lipolytic effects of growth hormone (GH) have been known for half a century and play an important physiological role for substrate metabolism during fasting. In addition, sustained GH-induced lipolysis is causally linked to insulin resistance. However, the underlying molecular mechanisms remain elusive. In the present study, we obtained experimental data in human subjects and used human adipose-derived stromal vascular cells (hADSCs) as a model system to elucidate GH-triggered molecular signaling that stimulates adipose tissue lipolysis and insulin resistance in human adipocytes. We discovered that GH downregulates the expression of fat-specific protein (FSP27), a negative regulator of lipolysis, by impairing the transcriptional ability of the master transcriptional regulator, peroxisome proliferator-activated receptor-γ (PPARγ) via MEK/ERK activation. Ultimately, GH treatment promotes phosphorylation of PPARγ at Ser273 and causes its translocation from nucleus to the cytosol. Surprisingly, FSP27 overexpression inhibited PPARγ Ser273 phosphorylation and promoted its nuclear retention. GH antagonist treatment had similar effects. Our study identifies a novel signaling mechanism by which GH transcriptionally induces lipolysis via the MEK/ERK pathway that acts along PPARγ-FSP27 in human adipose tissue.
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Affiliation(s)
- Vishva M Sharma
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University , Athens, Ohio
- The Diabetes Institute, Ohio University , Athens, Ohio
| | - Esben Thyssen Vestergaard
- Medical Research Laboratory, Aarhus University , Aarhus , Denmark
- Department of Pediatrics, Randers Regional Hospital, Randers, Denmark
| | - Niels Jessen
- Medical Research Laboratory, Aarhus University , Aarhus , Denmark
- Research Laboratory for Biochemical Pathology, Aarhus University Hospital , Aarhus , Denmark
- Department of Endocrinology and Internal Medicine, Aarhus University Hospital , Aarhus , Denmark
| | - Peter Kolind-Thomsen
- Medical Research Laboratory, Aarhus University , Aarhus , Denmark
- Research Laboratory for Biochemical Pathology, Aarhus University Hospital , Aarhus , Denmark
- Department of Endocrinology and Internal Medicine, Aarhus University Hospital , Aarhus , Denmark
| | | | - Thomas S Nielsen
- Medical Research Laboratory, Aarhus University , Aarhus , Denmark
- Faculty of Health and Medical Sciences, The Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen , Copenhagen , Denmark
| | - Mikkel Holm Vendelbo
- Medical Research Laboratory, Aarhus University , Aarhus , Denmark
- Department of Nuclear Medicine and PET Center, Aarhus University Hospital , Aarhus , Denmark
| | - Niels Møller
- Medical Research Laboratory, Aarhus University , Aarhus , Denmark
- Department of Endocrinology and Internal Medicine, Aarhus University Hospital , Aarhus , Denmark
| | - Rita Sharma
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University , Athens, Ohio
- The Diabetes Institute, Ohio University , Athens, Ohio
| | - Kevin Y Lee
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University , Athens, Ohio
- The Diabetes Institute, Ohio University , Athens, Ohio
| | - John J Kopchick
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University , Athens, Ohio
- The Diabetes Institute, Ohio University , Athens, Ohio
- Edison Biotechnology Institute, Ohio University , Athens, Ohio
| | - Jens Otto Lunde Jørgensen
- Medical Research Laboratory, Aarhus University , Aarhus , Denmark
- Department of Endocrinology and Internal Medicine, Aarhus University Hospital , Aarhus , Denmark
| | - Vishwajeet Puri
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University , Athens, Ohio
- The Diabetes Institute, Ohio University , Athens, Ohio
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18
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Small L, Brandon AE, Quek LE, Krycer JR, James DE, Turner N, Cooney GJ. Acute activation of pyruvate dehydrogenase increases glucose oxidation in muscle without changing glucose uptake. Am J Physiol Endocrinol Metab 2018; 315:E258-E266. [PMID: 29406780 DOI: 10.1152/ajpendo.00386.2017] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Pyruvate dehydrogenase (PDH) activity is a key component of the glucose/fatty acid cycle hypothesis for the regulation of glucose uptake and metabolism. We have investigated whether acute activation of PDH in muscle can alleviate the insulin resistance caused by feeding animals a high-fat diet (HFD). The importance of PDH activity in muscle glucose disposal under insulin-stimulated conditions was determined by infusing the PDH kinase inhibitor dichloroacetate (DCA) into HFD-fed Wistar rats during a hyperinsulinemic-euglycemic clamp. Acute DCA infusion did not alter glucose infusion rate, glucose disappearance, or hepatic glucose production but did decrease plasma lactate levels. DCA substantially increased muscle PDH activity; however, this did not improve insulin-stimulated glucose uptake in insulin-resistant muscle of HFD rats. DCA infusion increased the flux of pyruvate to acetyl-CoA and reduced glucose incorporation into glycogen and alanine in muscle. Similarly, in isolated muscle, DCA treatment increased glucose oxidation and decreased glycogen synthesis without changing glucose uptake. These results suggest that, although PDH activity controls the conversion of pyruvate to acetyl-CoA for oxidation, this has little effect on glucose uptake into muscle under insulin-stimulated conditions.
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Affiliation(s)
- Lewin Small
- Diabetes and Metabolism Division, Garvan Institute , Sydney, New South Wales , Australia
| | - Amanda E Brandon
- Diabetes and Metabolism Division, Garvan Institute , Sydney, New South Wales , Australia
- School of Medical Science, The University of Sydney, Charles Perkins Centre , New South Wales , Australia
| | - Lake-Ee Quek
- School of Mathematics and Statistics, The University of Sydney, Charles Perkins Centre , New South Wales , Australia
| | - James R Krycer
- School of Life and Environmental Science, The University of Sydney, Charles Perkins Centre , New South Wales , Australia
| | - David E James
- School of Life and Environmental Science, The University of Sydney, Charles Perkins Centre , New South Wales , Australia
| | - Nigel Turner
- Department of Pharmacology, School of Medical Science, University of New South Wales , Sydney, New South Wales , Australia
| | - Gregory J Cooney
- Diabetes and Metabolism Division, Garvan Institute , Sydney, New South Wales , Australia
- School of Medical Science, The University of Sydney, Charles Perkins Centre , New South Wales , Australia
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19
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Basu R, Qian Y, Kopchick JJ. MECHANISMS IN ENDOCRINOLOGY: Lessons from growth hormone receptor gene-disrupted mice: are there benefits of endocrine defects? Eur J Endocrinol 2018; 178:R155-R181. [PMID: 29459441 DOI: 10.1530/eje-18-0018] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Accepted: 02/19/2018] [Indexed: 12/12/2022]
Abstract
Growth hormone (GH) is produced primarily by anterior pituitary somatotroph cells. Numerous acute human (h) GH treatment and long-term follow-up studies and extensive use of animal models of GH action have shaped the body of GH research over the past 70 years. Work on the GH receptor (R)-knockout (GHRKO) mice and results of studies on GH-resistant Laron Syndrome (LS) patients have helped define many physiological actions of GH including those dealing with metabolism, obesity, cancer, diabetes, cognition and aging/longevity. In this review, we have discussed several issues dealing with these biological effects of GH and attempt to answer the question of whether decreased GH action may be beneficial.
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Affiliation(s)
- Reetobrata Basu
- Edison Biotechnology Institute, Ohio University, Athens, Ohio, USA
| | - Yanrong Qian
- Edison Biotechnology Institute, Ohio University, Athens, Ohio, USA
| | - John J Kopchick
- Edison Biotechnology Institute, Ohio University, Athens, Ohio, USA
- Ohio University Heritage College of Osteopathic Medicine, Ohio University, Athens, Ohio, USA
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20
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Bergan-Roller HE, Sheridan MA. The growth hormone signaling system: Insights into coordinating the anabolic and catabolic actions of growth hormone. Gen Comp Endocrinol 2018; 258:119-133. [PMID: 28760716 DOI: 10.1016/j.ygcen.2017.07.028] [Citation(s) in RCA: 90] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Revised: 07/19/2017] [Accepted: 07/27/2017] [Indexed: 12/16/2022]
Abstract
Although growth hormone (GH) is a multifunctional factor that coordinates various aspects of feeding, reproduction, osmoregulation, and immune system function, perhaps two of its most studied actions are the regulation of growth and metabolism, particularly lipid metabolism. In this review, we describe the major growth-promoting and lipid metabolic actions of GH and then discuss how the GH system regulates these actions. Numerous intrinsic and extrinsic factors provide information about the metabolic status of the organism and influence the production of release of GH. The actions of GH are mediated by GH receptors (GHR), which are widely distributed among tissues. Teleosts possess multiple forms of GHRs that arose through the evolution of this group. Modulation of tissue responsiveness to GH is regulated by molecular and functional expression of GHRs, and in teleosts GHR subtypes, by various factors that reflect the metabolic and growth status of the organism, including nutritional state. The action of GH is propagated by the linkage of GHRs to several cellular effector systems, including JAK-STAT, ERK, PI3K-Akt, and PKC. The differential activation of these pathways, which is governed by nutrient status, underlies GH stimulation of growth or GH stimulation of lipolysis. Taken together, the multi-functional actions of GH are determined by the distribution and abundance of GHRs (and GHR subtypes in teleosts) as well as by the GHR-effector system linkages.
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Affiliation(s)
| | - Mark A Sheridan
- Department of Biological Sciences, Texas Tech University, Lubbock, TX 79409 USA.
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21
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Zhang Y, Zhang Y, Ding GL, Liu XM, Ye J, Sheng JZ, Fan J, Huang HF. Regulation of hepatic pyruvate dehydrogenase phosphorylation in offspring glucose intolerance induced by intrauterine hyperglycemia. Oncotarget 2017; 8:15205-15212. [PMID: 28148899 PMCID: PMC5362479 DOI: 10.18632/oncotarget.14837] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Accepted: 01/11/2017] [Indexed: 01/07/2023] Open
Abstract
Aim Gestational diabetes mellitus (GDM) has been shown to be associated with a high risk of diabetes in offspring. In mitochondria, the inhibition of pyruvate dehydrogenase (PDH) activity by PDH phosphorylation is involved in the development of diabetes. We aimed to determine the role of PDH phosphorylation in the liver in GDM-induced offspring glucose intolerance. Results PDH phosphorylation was increased in lymphocytes from the umbilical cord blood of the GDM patients and in high glucose-treated hepatic cells. Both the male and female offspring from GDM mice had elevated liver weights and glucose intolerance. Further, PDH phosphorylation was increased in the livers of both the male and female offspring from GDM mice, and elevated acetylation may have contributed to this increased phosphorylation. Materials and methods We obtained lymphocytes from umbilical cord blood collected from both normal and GDM pregnant women. In addition, we obtained the offspring of streptozotocin-induced GDM female pregnant mice. The glucose tolerance test was performed to assess glucose tolerance in the offspring. Further, Western blotting was conducted to detect changes in protein levels. Conclusions Intrauterine hyperglycemia induced offspring glucose intolerance by inhibiting PDH activity, along with increased PDH phosphorylation in the liver, and this effect might be mediated by enhanced mitochondrial protein acetylation.
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Affiliation(s)
- Yong Zhang
- International Peace Maternity and Child Health Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200030, China.,Institute of Embryo-Fetal Original Adult Disease, School of Medicine, Shanghai Jiao Tong University, Shanghai 200030, China
| | - Ying Zhang
- International Peace Maternity and Child Health Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200030, China
| | - Guo-Lian Ding
- International Peace Maternity and Child Health Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200030, China
| | - Xin-Mei Liu
- International Peace Maternity and Child Health Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200030, China
| | - Jianping Ye
- Antioxidant and Gene Regulation Laboratory, Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, LA 70808, USA
| | - Jian-Zhong Sheng
- Department of Pathophysiology, School of Medicine, Zhejiang University, Hangzhou 310058, China
| | - Jianxia Fan
- International Peace Maternity and Child Health Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200030, China
| | - He-Feng Huang
- International Peace Maternity and Child Health Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200030, China.,Institute of Embryo-Fetal Original Adult Disease, School of Medicine, Shanghai Jiao Tong University, Shanghai 200030, China
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22
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Contreras GA, Strieder-Barboza C, Raphael W. Adipose tissue lipolysis and remodeling during the transition period of dairy cows. J Anim Sci Biotechnol 2017; 8:41. [PMID: 28484594 PMCID: PMC5420123 DOI: 10.1186/s40104-017-0174-4] [Citation(s) in RCA: 97] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Accepted: 04/11/2017] [Indexed: 12/12/2022] Open
Abstract
Elevated concentrations of plasma fatty acids in transition dairy cows are significantly associated with increased disease susceptibility and poor lactation performance. The main source of plasma fatty acids throughout the transition period is lipolysis from adipose tissue depots. During this time, plasma fatty acids serve as a source of calories mitigating the negative energy balance prompted by copious milk synthesis and limited dry matter intake. Past research has demonstrated that lipolysis in the adipose organ is a complex process that includes not only the activation of lipolytic pathways in response to neural, hormonal, or paracrine stimuli, but also important changes in the structure and cellular distribution of the tissue in a process known as adipose tissue remodeling. This process involves an inflammatory response with immune cell migration, proliferation of the cellular components of the stromal vascular fraction, and changes in the extracellular matrix. This review summarizes current knowledge on lipolysis in dairy cattle, expands on the new field of adipose tissue remodeling, and discusses how these biological processes affect transition cow health and productivity.
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Affiliation(s)
- G Andres Contreras
- Department of Large Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, MI 48824 USA
| | - Clarissa Strieder-Barboza
- Department of Large Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, MI 48824 USA
| | - William Raphael
- Department of Large Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, MI 48824 USA
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23
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Poidvin A, Weill A, Ecosse E, Coste J, Carel JC. Risk of Diabetes Treated in Early Adulthood After Growth Hormone Treatment of Short Stature in Childhood. J Clin Endocrinol Metab 2017; 102:1291-1298. [PMID: 28324032 DOI: 10.1210/jc.2016-3145] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Accepted: 01/05/2017] [Indexed: 12/26/2022]
Abstract
CONTEXT Growth hormone (GH) is known to be diabetogenic, but the risk of diabetes in individuals treated with GH in childhood has been little evaluated, and conflicting results have been obtained. OBJECTIVE To investigate the prevalence of diabetes and gestational diabetes in a population-based cohort of patients treated with GH for short stature in childhood in France. DESIGN, SETTING, AND PARTICIPANTS Participants were a population-based cohort of 5100 children with idiopathic isolated GH deficiency, idiopathic short stature, or short stature in children born short for gestational age who started GH treatment between 1985 and 1996. Data on the delivery of diabetes drugs in 2009 and 2010 were obtained from the French national health insurance database. Cases in patients and controls were identified from diabetes drugs deliveries. MAIN OUTCOME MEASURE The prevalence of diabetes was calculated and compared with that in the general population, determined on the basis of data from the same source, with the same definition. RESULTS At a mean age of 30 years, no difference in the prevalence of treated diabetes (oral drugs or insulin) was found between subjects treated with GH and the general population in France, regardless of sex. Similarly, the risk of insulin-treated gestational diabetes was similar in patients and in the reference population. CONCLUSIONS No difference in the risk of diabetes was found between GH-treated patients and the reference population. These results are reassuring, but further studies with a longer follow-up are required to evaluate the risk of diabetes with age in these patients.
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Affiliation(s)
- Amélie Poidvin
- Université Paris Diderot, Sorbonne Paris Cité, Paris 75019, France
- Assistance Publique-Hôpitaux de Paris, Hôpital Universitaire Robert-Debré, Department of Pediatric Endocrinology and Diabetology, and Centre de Référence des Maladies Endocriniennes Rares de la Croissance, Paris 75019, France
- Neuroprotection du cerveau en développement, INSERM, Unversité Paris Diderot, Sorbonne Paris Cité, Paris 75019, France
- Hôtel Dieu, Assistance Publique-Hôpitaux de Paris, Biostatistics and Epidemiology Unit, and APEMAC Equipe d'Accueil 4360, Paris 75004, France
| | - Alain Weill
- Department of Studies in Public Health, French National Health Insurance, Paris 75986, France
| | - Emmanuel Ecosse
- Hôtel Dieu, Assistance Publique-Hôpitaux de Paris, Biostatistics and Epidemiology Unit, and APEMAC Equipe d'Accueil 4360, Paris 75004, France
| | - Joel Coste
- Hôtel Dieu, Assistance Publique-Hôpitaux de Paris, Biostatistics and Epidemiology Unit, and APEMAC Equipe d'Accueil 4360, Paris 75004, France
| | - Jean-Claude Carel
- Université Paris Diderot, Sorbonne Paris Cité, Paris 75019, France
- Assistance Publique-Hôpitaux de Paris, Hôpital Universitaire Robert-Debré, Department of Pediatric Endocrinology and Diabetology, and Centre de Référence des Maladies Endocriniennes Rares de la Croissance, Paris 75019, France
- Neuroprotection du cerveau en développement, INSERM, Unversité Paris Diderot, Sorbonne Paris Cité, Paris 75019, France
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24
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Zimmer AD, Walbrecq G, Kozar I, Behrmann I, Haan C. Phosphorylation of the pyruvate dehydrogenase complex precedes HIF-1-mediated effects and pyruvate dehydrogenase kinase 1 upregulation during the first hours of hypoxic treatment in hepatocellular carcinoma cells. HYPOXIA 2016; 4:135-145. [PMID: 27800515 PMCID: PMC5085306 DOI: 10.2147/hp.s99044] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The pyruvate dehydrogenase complex (PDC) is an important gatekeeper enzyme connecting glycolysis to the tricarboxylic acid (TCA) cycle and oxidative phosphorylation (OXPHOS). Thereby, it has a strong impact on the glycolytic flux as well as the metabolic phenotype of a cell. PDC activity is regulated via reversible phosphorylation of three serine residues on the pyruvate dehydrogenase (PDH) E1α subunit. Phosphorylation of any of these residues by the PDH kinases (PDKs) leads to a strong decrease in PDC activity. Under hypoxia, the inactivation of the PDC has been described to be dependent on the hypoxia-inducible factor 1 (HIF-1)-induced PDK1 protein upregulation. In this study, we show in two hepatocellular carcinoma cell lines (HepG2 and JHH-4) that, during the adaptation to hypoxia, PDH is already phosphorylated at time points preceding HIF-1-mediated transcriptional events and PDK1 protein upregulation. Using siRNAs and small molecule inhibitor approaches, we show that this inactivation of PDC is independent of HIF-1α expression but that the PDKs need to be expressed and active. Furthermore, we show that reactive oxygen species might be important for the induction of this PDH phosphorylation since it correlates with the appearance of an altered redox state in the mitochondria and is also inducible by H2O2 treatment under normoxic conditions. Overall, these results show that neither HIF-1 expression nor PDK1 upregulation is necessary for the phosphorylation of PDH during the first hours of the adaptation to hypoxia.
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Affiliation(s)
| | - Geoffroy Walbrecq
- Life Sciences Research Unit, University of Luxembourg, Belvaux, Luxembourg
| | - Ines Kozar
- Life Sciences Research Unit, University of Luxembourg, Belvaux, Luxembourg
| | - Iris Behrmann
- Life Sciences Research Unit, University of Luxembourg, Belvaux, Luxembourg
| | - Claude Haan
- Life Sciences Research Unit, University of Luxembourg, Belvaux, Luxembourg
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25
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Klil-Drori AJ, Azoulay L, Pollak MN. Cancer, obesity, diabetes, and antidiabetic drugs: is the fog clearing? Nat Rev Clin Oncol 2016; 14:85-99. [DOI: 10.1038/nrclinonc.2016.120] [Citation(s) in RCA: 137] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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26
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Olarescu NC, Bollerslev J. The Impact of Adipose Tissue on Insulin Resistance in Acromegaly. Trends Endocrinol Metab 2016; 27:226-237. [PMID: 26948712 DOI: 10.1016/j.tem.2016.02.005] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2016] [Revised: 02/09/2016] [Accepted: 02/11/2016] [Indexed: 01/11/2023]
Abstract
Adipose tissue (AT) is recognized as key contributor to the systemic insulin resistance and overt diabetes seen in metabolic syndrome. Acromegaly is a disease characterized by excessive secretion of growth hormone (GH) and insulin-like growth factor I (IGF-I). GH is known both for its action on AT and for its detrimental effect on glucose metabolism and insulin signaling. In active acromegaly, while body fat deports are diminished, insulin resistance is increased. Early studies have demonstrated defects in insulin action, both at the hepatic and extrahepatic (i.e., muscle and fat) levels, in active disease. This review discusses recent data suggesting that AT inflammation, altered AT distribution, and impaired adipogenesis are potential mechanisms contributing to systemic insulin resistance in acromegaly.
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Affiliation(s)
- Nicoleta Cristina Olarescu
- Section of Specialized Endocrinology, Department of Endocrinology, Oslo University Hospital, Rikshospitalet, Oslo, Norway; Faculty of Medicine, University of Oslo, Norway.
| | - Jens Bollerslev
- Section of Specialized Endocrinology, Department of Endocrinology, Oslo University Hospital, Rikshospitalet, Oslo, Norway; Faculty of Medicine, University of Oslo, Norway
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27
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Echeverría-Rodríguez O, Gallardo-Ortíz IA, Villalobos-Molina R. Does exercise increase insulin sensitivity through angiotensin 1-7? Acta Physiol (Oxf) 2016; 216:3-6. [PMID: 26485319 DOI: 10.1111/apha.12619] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- O. Echeverría-Rodríguez
- Unidad de Investigación en Biomedicina; Facultad de Estudios Superiores Iztacala (FES-Iztacala); Universidad Nacional Autónoma de México (UNAM); Tlalnepantla Edo. de México Mexico
| | - I. A. Gallardo-Ortíz
- Unidad de Investigación en Biomedicina; Facultad de Estudios Superiores Iztacala (FES-Iztacala); Universidad Nacional Autónoma de México (UNAM); Tlalnepantla Edo. de México Mexico
| | - R. Villalobos-Molina
- Unidad de Investigación en Biomedicina; Facultad de Estudios Superiores Iztacala (FES-Iztacala); Universidad Nacional Autónoma de México (UNAM); Tlalnepantla Edo. de México Mexico
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28
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Dal J, List EO, Jørgensen JOL, Berryman DE. Glucose and Fat Metabolism in Acromegaly: From Mice Models to Patient Care. Neuroendocrinology 2016; 103:96-105. [PMID: 25925240 DOI: 10.1159/000430819] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Accepted: 04/20/2015] [Indexed: 11/19/2022]
Abstract
Patients with active acromegaly are frequently insulin resistant, glucose intolerant, and at risk for developing overt type 2 diabetes. At the same time, these patients have a relatively lean phenotype associated with mobilization and oxidation of free fatty acids. These features are reversed by curative surgical removal of the growth hormone (GH)-producing adenoma. Mouse models of acromegaly share many of these characteristics, including a lean phenotype and proneness to type 2 diabetes. There are, however, also species differences with respect to oxidation rates of glucose and fat as well as the specific mechanisms underlying GH-induced insulin resistance. The impact of acromegaly treatment on insulin sensitivity and glucose tolerance depends on the treatment modality (e.g. somatostatin analogs also suppress insulin secretion, whereas the GH antagonist restores insulin sensitivity). The interplay between animal research and clinical studies has proven useful in the field of acromegaly and should be continued in order to understand the metabolic actions of GH.
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Affiliation(s)
- Jakob Dal
- Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Aarhus, Denmark
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29
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Persson PB. Insulin. Acta Physiol (Oxf) 2015; 214:427-9. [PMID: 26100001 DOI: 10.1111/apha.12543] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- P B Persson
- Institute of Vegetative Physiology, Charité-Universitaetsmedizin Berlin, Berlin, Germany.
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30
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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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31
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Abstract
The pyruvate dehydrogenase complex (PDC) is an emerging target for the treatment of metabolic syndrome. To maintain a steady-state concentration of adenosine triphosphate during the feed-fast cycle, cells require efficient utilization of fatty acid and glucose, which is controlled by the PDC. The PDC converts pyruvate, coenzyme A (CoA), and oxidized nicotinamide adenine dinucleotide (NAD(+)) into acetyl-CoA, reduced form of nicotinamide adenine dinucleotide (NADH), and carbon dioxide. The activity of the PDC is up- and down-regulated by pyruvate dehydrogenase kinase and pyruvate dehydrogenase phosphatase, respectively. In addition, pyruvate is a key intermediate of glucose oxidation and an important precursor for the synthesis of glucose, glycerol, fatty acids, and nonessential amino acids.
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Affiliation(s)
- In-Kyu Lee
- Department of Internal Medicine, Kyungpook National University School of Medicine, Daegu, Korea
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32
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Zhang S, Hulver MW, McMillan RP, Cline MA, Gilbert ER. The pivotal role of pyruvate dehydrogenase kinases in metabolic flexibility. Nutr Metab (Lond) 2014; 11:10. [PMID: 24520982 PMCID: PMC3925357 DOI: 10.1186/1743-7075-11-10] [Citation(s) in RCA: 309] [Impact Index Per Article: 30.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Accepted: 02/08/2014] [Indexed: 01/26/2023] Open
Abstract
Metabolic flexibility is the capacity of a system to adjust fuel (primarily glucose and fatty acids) oxidation based on nutrient availability. The ability to alter substrate oxidation in response to nutritional state depends on the genetically influenced balance between oxidation and storage capacities. Competition between fatty acids and glucose for oxidation occurs at the level of the pyruvate dehydrogenase complex (PDC). The PDC is normally active in most tissues in the fed state, and suppressing PDC activity by pyruvate dehydrogenase (PDH) kinase (PDK) is crucial to maintain energy homeostasis under some extreme nutritional conditions in mammals. Conversely, inappropriate suppression of PDC activity might promote the development of metabolic diseases. This review summarizes PDKs’ pivotal role in control of metabolic flexibility under various nutrient conditions and in different tissues, with emphasis on the best characterized PDK4. Understanding the regulation of PDC and PDKs and their roles in energy homeostasis could be beneficial to alleviate metabolic inflexibility and to provide possible therapies for metabolic diseases, including type 2 diabetes (T2D).
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Affiliation(s)
| | | | | | | | - Elizabeth R Gilbert
- Department of Animal and Poultry Sciences, Virginia Tech, Blacksburg, VA USA.
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