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Dutta S, Shah RB, Singhal S, Dutta SB, Bansal S, Sinha S, Haque M. Metformin: A Review of Potential Mechanism and Therapeutic Utility Beyond Diabetes. Drug Des Devel Ther 2023; 17:1907-1932. [PMID: 37397787 PMCID: PMC10312383 DOI: 10.2147/dddt.s409373] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Accepted: 06/10/2023] [Indexed: 07/04/2023] Open
Abstract
Metformin has been designated as one of the most crucial first-line therapeutic agents in the management of type 2 diabetes mellitus. Primarily being an antihyperglycemic agent, metformin also has a plethora of pleiotropic effects on various systems and processes. It acts majorly by activating AMPK (Adenosine Monophosphate-Activated Protein Kinase) in the cells and reducing glucose output from the liver. It also decreases advanced glycation end products and reactive oxygen species production in the endothelium apart from regulating the glucose and lipid metabolism in the cardiomyocytes, hence minimizing the cardiovascular risks. Its anticancer, antiproliferative and apoptosis-inducing effects on malignant cells might prove instrumental in the malignancy of organs like the breast, kidney, brain, ovary, lung, and endometrium. Preclinical studies have also shown some evidence of metformin's neuroprotective role in Parkinson's disease, Alzheimer's disease, multiple sclerosis and Huntington's disease. Metformin exerts its pleiotropic effects through varied pathways of intracellular signalling and exact mechanism in the majority of them remains yet to be clearly defined. This article has extensively reviewed the therapeutic benefits of metformin and the details of its mechanism for a molecule of boon in various conditions like diabetes, prediabetes, obesity, polycystic ovarian disease, metabolic derangement in HIV, various cancers and aging.
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Affiliation(s)
- Siddhartha Dutta
- Department of Pharmacology, All India Institute of Medical Sciences, Rajkot, Gujarat, India
| | - Rima B Shah
- Department of Pharmacology, All India Institute of Medical Sciences, Rajkot, Gujarat, India
| | - Shubha Singhal
- Department of Pharmacology, All India Institute of Medical Sciences, Rajkot, Gujarat, India
| | - Sudeshna Banerjee Dutta
- Department of Medical Surgical Nursing, Shri Anand Institute of Nursing, Rajkot, Gujarat, 360005, India
| | - Sumit Bansal
- Department of Anaesthesiology, All India Institute of Medical Sciences, Rajkot, Gujarat, India
| | - Susmita Sinha
- Department of Physiology, Khulna City Medical College and Hospital, Khulna, Bangladesh
| | - Mainul Haque
- Unit of Pharmacology, Faculty of Medicine and Defence Health, Universiti Pertahanan Nasional Malaysia (National Defence University of Malaysia), Kuala Lumpur, 57000, Malaysia
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2
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Aoi W, Inoue R, Mizushima K, Honda A, Björnholm M, Takagi T, Naito Y. Exercise-acclimated microbiota improves skeletal muscle metabolism via circulating bile acid deconjugation. iScience 2023; 26:106251. [PMID: 36915683 PMCID: PMC10005909 DOI: 10.1016/j.isci.2023.106251] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 10/31/2022] [Accepted: 02/16/2023] [Indexed: 02/23/2023] Open
Abstract
Habitual exercise alters the intestinal microbiota composition, which may mediate its systemic benefits. We examined whether transplanting fecal microbiota from trained mice improved skeletal muscle metabolism in high-fat diet (HFD)-fed mice. Fecal samples from sedentary and exercise-trained mice were gavage-fed to germ-free mice. After receiving fecal samples from trained donor mice for 1 week, recipient mice had elevated levels of AMP-activated protein kinase (AMPK) and insulin growth factor-1 in skeletal muscle. In plasma, bile acid (BA) deconjugation was found to be promoted in recipients transplanted with feces from trained donor mice; free-form BAs also induced more AMPK signaling and glucose uptake than tauro-conjugated BAs. The transplantation of exercise-acclimated fecal microbiota improved glucose tolerance after 8 weeks of HFD administration. Intestinal microbiota may mediate exercise-induced metabolic improvements in mice by modifying circulating BAs. Our findings provide insights into the prevention and treatment of metabolic diseases.
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Affiliation(s)
- Wataru Aoi
- Division of Applied Life Sciences, Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Kyoto 6068522, Japan
| | - Ryo Inoue
- Laboratory of Animal Science, Department of Applied Biological Sciences, Faculty of Agriculture, Setsunan University, Osaka 5730101, Japan
| | - Katsura Mizushima
- Department of Human Immunology and Nutrition Science, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto 6028566, Japan
| | - Akira Honda
- Gastroenterology, Tokyo Medical University Ibaraki Medical Center, Ibaraki 3000395, Japan
| | - Marie Björnholm
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm 17176, Sweden
| | - Tomohisa Takagi
- Molecular Gastroenterology and Hepatology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto 6028566, Japan.,Department for Medical Innovation and Translational Medical Science, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto 6028566, Japan
| | - Yuji Naito
- Department of Human Immunology and Nutrition Science, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto 6028566, Japan
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de Campos Zani SC, Son M, Bhullar KS, Chan CB, Wu J. IRW (Isoleucine-Arginine-Tryptophan) Improves Glucose Tolerance in High Fat Diet Fed C57BL/6 Mice via Activation of Insulin Signaling and AMPK Pathways in Skeletal Muscle. Biomedicines 2022; 10:biomedicines10061235. [PMID: 35740257 PMCID: PMC9220315 DOI: 10.3390/biomedicines10061235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 05/24/2022] [Accepted: 05/25/2022] [Indexed: 02/01/2023] Open
Abstract
IRW (Isoleucine−Arginine−Tryptophan), has antihypertensive and anti-inflammatory properties in cells and animal models and prevents angiotensin-II- and tumor necrosis factor (TNF)-α-induced insulin resistance (IR) in vitro. We investigated the effects of IRW on body composition, glucose homeostasis and insulin sensitivity in a high-fat diet (HFD) induced insulin resistant (IR) model. C57BL/6 mice were fed HFD for 6 weeks, after which IRW was incorporated into the diet (45 or 15 mg/kg body weight (BW)) until week 14. IRW45 (at a dose of 45 mg/kg BW) reduced BW (p = 0.0327), fat mass gain (p = 0.0085), and preserved lean mass of HFD mice (p = 0.0065), concomitant with enhanced glucose tolerance and reduced fasting glucose (p < 0.001). In skeletal muscle, IRW45 increased insulin-stimulated protein kinase B (AKT) phosphorylation (p = 0.0132) and glucose transporter 4 (GLUT4) translocation (p < 0.001). Angiotensin 2 receptor (AT2R) (p = 0.0024), phosphorylated 5′-AMP-activated protein kinase (AMPKα) (p < 0.0124) and peroxisome proliferator-activated receptor gamma (PPARγ) (p < 0.001) were enhanced in skeletal muscle of IRW45-treated mice, as was the expression of genes involved in myogenesis. Plasma angiotensin converting enzyme-2 (ACE2) activity was increased (p = 0.0016). Uncoupling protein-1 in white adipose tissue (WAT) was partially restored after IRW supplementation. IRW improves glucose tolerance and body composition in HFD-fed mice and promotes glucose uptake in skeletal muscle via multiple signaling pathways, independent of angiotensin converting enzyme (ACE) inhibition.
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Affiliation(s)
| | - Myoungjin Son
- Department of Agricultural Food & Nutritional Science, University of Alberta, Edmonton, AB T6G 2P5, Canada; (M.S.); (K.S.B.)
| | - Khushwant S. Bhullar
- Department of Agricultural Food & Nutritional Science, University of Alberta, Edmonton, AB T6G 2P5, Canada; (M.S.); (K.S.B.)
- Department of Pharmacology, University of Alberta, Edmonton, AB T6G 2H7, Canada
| | - Catherine B. Chan
- Department of Physiology, University of Alberta, Edmonton, AB T6G 2H7, Canada; (S.C.d.C.Z.); (C.B.C.)
- Department of Agricultural Food & Nutritional Science, University of Alberta, Edmonton, AB T6G 2P5, Canada; (M.S.); (K.S.B.)
| | - Jianping Wu
- Department of Agricultural Food & Nutritional Science, University of Alberta, Edmonton, AB T6G 2P5, Canada; (M.S.); (K.S.B.)
- Correspondence: ; Tel.: +1-780-492-6885; Fax: +1-780-492-4346
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4
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The role of AMPK in regulation of Na +,K +-ATPase in skeletal muscle: does the gauge always plug the sink? J Muscle Res Cell Motil 2021; 42:77-97. [PMID: 33398789 DOI: 10.1007/s10974-020-09594-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Accepted: 12/14/2020] [Indexed: 12/14/2022]
Abstract
AMP-activated protein kinase (AMPK) is a cellular energy gauge and a major regulator of cellular energy homeostasis. Once activated, AMPK stimulates nutrient uptake and the ATP-producing catabolic pathways, while it suppresses the ATP-consuming anabolic pathways, thus helping to maintain the cellular energy balance under energy-deprived conditions. As much as ~ 20-25% of the whole-body ATP consumption occurs due to a reaction catalysed by Na+,K+-ATPase (NKA). Being the single most important sink of energy, NKA might seem to be an essential target of the AMPK-mediated energy saving measures, yet NKA is vital for maintenance of transmembrane Na+ and K+ gradients, water homeostasis, cellular excitability, and the Na+-coupled transport of nutrients and ions. Consistent with the model that AMPK regulates ATP consumption by NKA, activation of AMPK in the lung alveolar cells stimulates endocytosis of NKA, thus suppressing the transepithelial ion transport and the absorption of the alveolar fluid. In skeletal muscles, contractions activate NKA, which opposes a rundown of transmembrane ion gradients, as well as AMPK, which plays an important role in adaptations to exercise. Inhibition of NKA in contracting skeletal muscle accentuates perturbations in ion concentrations and accelerates development of fatigue. However, different models suggest that AMPK does not inhibit or even stimulates NKA in skeletal muscle, which appears to contradict the idea that AMPK maintains the cellular energy balance by always suppressing ATP-consuming processes. In this short review, we examine the role of AMPK in regulation of NKA in skeletal muscle and discuss the apparent paradox of AMPK-stimulated ATP consumption.
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Shrestha MM, Lim CY, Bi X, Robinson RC, Han W. Tmod3 Phosphorylation Mediates AMPK-Dependent GLUT4 Plasma Membrane Insertion in Myoblasts. Front Endocrinol (Lausanne) 2021; 12:653557. [PMID: 33959097 PMCID: PMC8095187 DOI: 10.3389/fendo.2021.653557] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Accepted: 03/22/2021] [Indexed: 12/28/2022] Open
Abstract
Insulin and muscle contractions mediate glucose transporter 4 (GLUT4) translocation and insertion into the plasma membrane (PM) for glucose uptake in skeletal muscles. Muscle contraction results in AMPK activation, which promotes GLUT4 translocation and PM insertion. However, little is known regarding AMPK effectors that directly regulate GLUT4 translocation. We aim to identify novel AMPK effectors in the regulation of GLUT4 translocation. We performed biochemical, molecular biology and fluorescent microscopy imaging experiments using gain- and loss-of-function mutants of tropomodulin 3 (Tmod3). Here we report Tmod3, an actin filament capping protein, as a novel AMPK substrate and an essential mediator of AMPK-dependent GLUT4 translocation and glucose uptake in myoblasts. Furthermore, Tmod3 plays a key role in AMPK-induced F-actin remodeling and GLUT4 insertion into the PM. Our study defines Tmod3 as a key AMPK effector in the regulation of GLUT4 insertion into the PM and glucose uptake in muscle cells, and offers new mechanistic insights into the regulation of glucose homeostasis.
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Affiliation(s)
- Man Mohan Shrestha
- Laboratory of Metabolic Medicine, Singapore Bioimaging Consortium, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| | - Chun-Yan Lim
- Laboratory of Metabolic Medicine, Singapore Bioimaging Consortium, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| | - Xuezhi Bi
- Bioprocessing Technology Institute, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| | - Robert C. Robinson
- Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| | - Weiping Han
- Laboratory of Metabolic Medicine, Singapore Bioimaging Consortium, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
- Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
- *Correspondence: Weiping Han,
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6
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Low-Intensity Exercise Training Additionally Increases Mitochondrial Dynamics Caused by High-Fat Diet (HFD) but Has No Additional Effect on Mitochondrial Biogenesis in Fast-Twitch Muscle by HFD. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2020; 17:ijerph17155461. [PMID: 32751208 PMCID: PMC7432492 DOI: 10.3390/ijerph17155461] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 07/27/2020] [Accepted: 07/28/2020] [Indexed: 01/07/2023]
Abstract
This study examines how the high-fat diet (HFD) affects mitochondrial dynamics and biogenesis, and also whether combining it with low-intensity endurance exercise adds to these effects. Six 8-week-old male Sprague–Dawley (SD) rats were put on control (CON; standard chow diet), HF (HFD intake), and HFEx (HFD + low-intensity treadmill exercise) for 6 weeks. As a result, no change in body weight was observed among the groups. However, epididymal fat mass increased significantly in the two groups that had been given HFD. Blood free fatty acid (FFA) also increased significantly in the HF group. While HFD increased insulin resistance (IR), this was improved significantly in the HFEx group. HFD also significantly increased mitochondrial biogenesis-related factors (PPARδ, PGC-1α, and mtTFA) and mitochondrial electron transport chain proteins; however, no additional effect from exercise was observed. Mitochondrial dynamic-related factors were also affected: Mfn2 increased significantly in the HFEx group, while Drp1 and Fis-1 increased significantly in both the HF and HFEx groups. The number of mitochondria in the subsarcolemmal region, and their size in the subsarcolemmal and intermyofibrillar regions, also increased significantly in the HFEx group. Taken overall, these results show that HFD in combination with low-intensity endurance exercise has no additive effect on mitochondrial biogenesis, although it does have such an effect on mitochondrial dynamics by improving IR.
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Novel antioxidant astaxanthin-s-allyl cysteine biconjugate diminished oxidative stress and mitochondrial dysfunction to triumph diabetes in rat model. Life Sci 2020; 245:117367. [PMID: 32001265 DOI: 10.1016/j.lfs.2020.117367] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2019] [Revised: 01/14/2020] [Accepted: 01/26/2020] [Indexed: 01/14/2023]
Abstract
AIMS The present study determines the effect of administration of novel antioxidant astaxanthin-s-allyl cysteine biconjugate (AST-SAC) against streptozotocin-induced diabetes mellitus (DM) in rats. MAIN METHODS AST-SAC (1 mg/kg/day) was treated against DM in rats for 45 days. The oxidative stress, antioxidants level, insulin secretion, activities of various carbohydrate metabolizing enzymes were studied. The glucose uptake in L6 myotubes was studied. In addition, in silico analysis of interaction of AST-SAC with proteins such as insulin receptor (IR) and 5'-adenosine monophosphate-activated protein kinase (AMPK) were carried out. KEY FINDINGS Administration of AST-SAC in DM rats has protected the mitochondrial function (decreased oxidative stress and normalized oxidative phosphorylation activities) and antioxidant capacity of the pancreas which has resulted in beta cells rejuvenation and insulin secretion restoration. AST-SAC decreased the alpha-glucosidases activities to bring glycemic control in DM rats. Due to these effects the glycoprotein components and lipids were restored to near normalcy in DM rats. AST-SAC protected the antioxidant status of liver, kidney and plasma; and curbed the progression of secondary complications of DM. AST-SAC treatment stimulated glucose uptake in L6 myotubes in in vitro. To support this observation, AST-SAC interacted with proteins such as IR and AMPK in silico. SIGNIFICANCE AST-SAC can be considered as "multi-target-directed ligand", that is, through these manifold effects, AST-SAC has been able to prevail over DM in rats.
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Aoi W, Hirano N, Lassiter DG, Björnholm M, Chibalin AV, Sakuma K, Tanimura Y, Mizushima K, Takagi T, Naito Y, Zierath JR, Krook A. Secreted protein acidic and rich in cysteine (SPARC) improves glucose tolerance via AMP-activated protein kinase activation. FASEB J 2019; 33:10551-10562. [PMID: 31225998 DOI: 10.1096/fj.201900453r] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
During exercise, skeletal muscles release cytokines, peptides, and metabolites that exert autocrine, paracrine, or endocrine effects on glucose homeostasis. In this study, we investigated the effects of secreted protein acidic and rich in cysteine (SPARC), an exercise-responsive myokine, on glucose metabolism in human and mouse skeletal muscle. SPARC-knockout mice showed impaired systemic metabolism and reduced phosphorylation of AMPK and protein kinase B in skeletal muscle. Treatment of SPARC-knockout mice with recombinant SPARC improved glucose tolerance and concomitantly activated AMPK in skeletal muscle. These effects were dependent on AMPK-γ3 because SPARC treatment enhanced skeletal muscle glucose uptake in wild-type mice but not in AMPK-γ3-knockout mice. SPARC strongly interacted with the voltage-dependent calcium channel, and inhibition of calcium-dependent signaling prevented SPARC-induced AMPK phosphorylation in human and mouse myotubes. Finally, chronic SPARC treatment improved systemic glucose tolerance and AMPK signaling in skeletal muscle of high-fat diet-induced obese mice, highlighting the efficacy of SPARC treatment in the management of metabolic diseases. Thus, our findings suggest that SPARC treatment mimics the effects of exercise on glucose tolerance by enhancing AMPK-dependent glucose uptake in skeletal muscle.-Aoi, W., Hirano, N., Lassiter, D. G., Björnholm, M., Chibalin, A. V., Sakuma, K., Tanimura, Y., Mizushima, K., Takagi, T., Naito, Y., Zierath, J. R., Krook, A. Secreted protein acidic and rich in cysteine (SPARC) improves glucose tolerance via AMP-activated protein kinase activation.
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Affiliation(s)
- Wataru Aoi
- Division of Applied Life Sciences, Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Kyoto, Japan.,Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Nariyuki Hirano
- Division of Applied Life Sciences, Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Kyoto, Japan
| | - David G Lassiter
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
| | - Marie Björnholm
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
| | - Alexander V Chibalin
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
| | - Kunihiro Sakuma
- Institute for Liberal Arts, School of Environment and Society, Tokyo Institute of Technology, Tokyo, Japan
| | - Yuko Tanimura
- Faculty of Human, Aichi-Toho University, Nagoya, Japan
| | - Katsura Mizushima
- Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Tomohisa Takagi
- Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Yuji Naito
- Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Juleen R Zierath
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden.,Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
| | - Anna Krook
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
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9
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Thomas LW, Ashcroft M. Exploring the molecular interface between hypoxia-inducible factor signalling and mitochondria. Cell Mol Life Sci 2019; 76:1759-1777. [PMID: 30767037 PMCID: PMC6453877 DOI: 10.1007/s00018-019-03039-y] [Citation(s) in RCA: 127] [Impact Index Per Article: 25.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Revised: 01/09/2019] [Accepted: 02/01/2019] [Indexed: 12/19/2022]
Abstract
Oxygen is required for the survival of the majority of eukaryotic organisms, as it is important for many cellular processes. Eukaryotic cells utilize oxygen for the production of biochemical energy in the form of adenosine triphosphate (ATP) generated from the catabolism of carbon-rich fuels such as glucose, lipids and glutamine. The intracellular sites of oxygen consumption-coupled ATP production are the mitochondria, double-membraned organelles that provide a dynamic and multifaceted role in cell signalling and metabolism. Highly evolutionarily conserved molecular mechanisms exist to sense and respond to changes in cellular oxygen levels. The primary transcriptional regulators of the response to decreased oxygen levels (hypoxia) are the hypoxia-inducible factors (HIFs), which play important roles in both physiological and pathophysiological contexts. In this review we explore the relationship between HIF-regulated signalling pathways and the mitochondria, including the regulation of mitochondrial metabolism, biogenesis and distribution.
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Affiliation(s)
- Luke W Thomas
- University of Cambridge, Cambridge Biomedical Campus, Cambridge, CB2 0AH, UK
| | - Margaret Ashcroft
- University of Cambridge, Cambridge Biomedical Campus, Cambridge, CB2 0AH, UK.
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10
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Liu X, Bauman WA, Cardozo CP. Myostatin inhibits glucose uptake via suppression of insulin-dependent and -independent signaling pathways in myoblasts. Physiol Rep 2018; 6:e13837. [PMID: 30252210 PMCID: PMC6121119 DOI: 10.14814/phy2.13837] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Revised: 07/19/2018] [Accepted: 07/25/2018] [Indexed: 11/24/2022] Open
Abstract
The glucose transporter 4 (Glut4) mediates insulin-dependent glucose uptake. Glut4 expression levels are correlated with whole-body glucose homeostasis. Insulin signaling is known to recruit Glut4 to the cell surface. Expression of Glut4 is subject to tissue-specific hormonal and metabolic regulation. The molecular mechanisms regulating skeletal muscle Glut4 expression remain to be elucidated. Myostatin (Mstn) is reported to be involved in the regulation of energy metabolism. While elevated Mstn levels in muscle are associated with obesity and type-2 diabetes in both human and mouse models, Mstn null mice exhibit immunity to dietary-induced obesity and insulin resistance. The molecular mechanisms by which Mstn initiates the development of insulin resistance and disorders of glucose disposal are not well delineated. Here we investigated effects of Mstn on insulin action in C2C12 cells. Mstn significantly reduced basal and insulin-induced IRS-1 tyrosine (Tyr495) phosphorylation, and expression and activation of PI3K, associated with diminished AKT phosphorylation and elevated GSK3β phosphorylation at Ser9. In addition, Mstn inhibited Glut4 mRNA and protein expression, and reduced insulin-induced Glut4 membrane translocation and glucose uptake. Conversely, SB431542, a Smad2/3 inhibitor, significantly increased cellular response to insulin. Mstn decreased AMP-activated protein kinase (AMPK) activity accompanied by reduced Glut4 gene expression and glucose uptake, which were partially reversed by AICAR, an AMPK activator. These data suggest that Mstn inhibits Glut4 expression and insulin-induced Glut4 integration into cytoplasmic membranes and glucose uptake and that these changes are mediated by direct insulin-desensitizing effect and indirect suppression of AMPK activation.
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Affiliation(s)
- Xin‐Hua Liu
- National Center for the Medical Consequences of Spinal Cord InjuryJames J. Peter VA Medical CenterBronxNew York
- Department of MedicineMount Sinai School of MedicineNew YorkNew York
| | - William A. Bauman
- National Center for the Medical Consequences of Spinal Cord InjuryJames J. Peter VA Medical CenterBronxNew York
- Department of MedicineMount Sinai School of MedicineNew YorkNew York
- Department of Rehabilitation MedicineMount Sinai School of MedicineNew YorkNew York
| | - Christopher P. Cardozo
- National Center for the Medical Consequences of Spinal Cord InjuryJames J. Peter VA Medical CenterBronxNew York
- Department of MedicineMount Sinai School of MedicineNew YorkNew York
- Department of Rehabilitation MedicineMount Sinai School of MedicineNew YorkNew York
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11
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Lim JH, Kim HW, Kim MY, Kim TW, Kim EN, Kim Y, Chung S, Kim YS, Choi BS, Kim YS, Chang YS, Kim HW, Park CW. Cinacalcet-mediated activation of the CaMKKβ-LKB1-AMPK pathway attenuates diabetic nephropathy in db/db mice by modulation of apoptosis and autophagy. Cell Death Dis 2018; 9:270. [PMID: 29449563 PMCID: PMC5833853 DOI: 10.1038/s41419-018-0324-4] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Revised: 01/05/2018] [Accepted: 01/15/2018] [Indexed: 02/06/2023]
Abstract
Apoptosis and autophagy are harmoniously regulated biological processes for maintaining tissue homeostasis. AMP-activated protein kinase (AMPK) functions as a metabolic sensor to coordinate cellular survival and function in various organs, including the kidney. We investigated the renoprotective effects of cinacalcet in high-glucose treated human glomerular endothelial cells (HGECs), murine podocytes and C57BLKS/J-db/db mice. In cultured HGECs and podocytes, cinacalcet decreased oxidative stress and apoptosis and increased autophagy that were attributed to the increment of intracellular Ca2+ concentration and the phosphorylation of Ca2+/calmodulin-dependent protein kinase kinaseβ (CaMKKβ)-Liver kinase B1 (LKB1)-AMPK and their downstream signals including the phosphorylation of endothelial nitric oxide synthase (eNOS) and increases in superoxide dismutases and B cell leukemia/lymphoma 2/BCL-2-associated X protein expression. Interestingly, intracellular chelator BAPTA-AM reversed cinacalcet-induced CaMKKβ elevation and LKB1 phosphorylation. Cinacalcet reduced albuminuria without influencing either blood glucose or Ca2+ concentration and ameliorated diabetes-induced renal damage, which were related to the increased expression of calcium-sensing receptor and the phosphorylation of CaMKKβ-LKB1. Subsequent activation of AMPK was followed by the activation of peroxisome proliferator-activated receptor γ coactivator-1α and phospho-Ser1177eNOS-nitric oxide, resulting in a decrease in apoptosis and oxidative stress as well as an increase in autophagy. Our results suggest that cinacalcet increases intracellular Ca2+ followed by an activation of CaMKKβ-LKB1-AMPK signaling in GECs and podocytes in the kidney, which provides a novel therapeutic means for type 2 diabetic nephropathy by modulation of apoptosis and autophagy.
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Affiliation(s)
- Ji Hee Lim
- Division of Nephrology, Department of Internal Medicine, The Catholic University of Korea, Seoul, Korea.,Institute for Aging and Metabolic Diseases, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Hyung Wook Kim
- Division of Nephrology, Department of Internal Medicine, St. Vincent's Hospital, College of Medicine, The Catholic University of Korea, Suwon, Korea
| | - Min Young Kim
- Division of Nephrology, Department of Internal Medicine, The Catholic University of Korea, Seoul, Korea.,Institute for Aging and Metabolic Diseases, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Tae Woo Kim
- Department of Hematology, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Eun Nim Kim
- Division of Nephrology, Department of Internal Medicine, The Catholic University of Korea, Seoul, Korea
| | - Yaeni Kim
- Division of Nephrology, Department of Internal Medicine, The Catholic University of Korea, Seoul, Korea
| | - Sungjin Chung
- Division of Nephrology, Department of Internal Medicine, The Catholic University of Korea, Seoul, Korea
| | - Young Soo Kim
- Division of Nephrology, Department of Internal Medicine, The Catholic University of Korea, Seoul, Korea
| | - Bum Soon Choi
- Division of Nephrology, Department of Internal Medicine, The Catholic University of Korea, Seoul, Korea
| | - Yong-Soo Kim
- Division of Nephrology, Department of Internal Medicine, The Catholic University of Korea, Seoul, Korea
| | - Yoon Sik Chang
- Division of Nephrology, Department of Internal Medicine, The Catholic University of Korea, Seoul, Korea
| | - Hye Won Kim
- Department of Rehabilitation Medicine, College of Medicine, The Catholic University of Korea, Bucheon, Korea
| | - Cheol Whee Park
- Division of Nephrology, Department of Internal Medicine, The Catholic University of Korea, Seoul, Korea. .,Institute for Aging and Metabolic Diseases, College of Medicine, The Catholic University of Korea, Seoul, Korea.
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12
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Mobbs JI, Di Paolo A, Metcalfe RD, Selig E, Stapleton DI, Griffin MDW, Gooley PR. Unravelling the Carbohydrate-Binding Preferences of the Carbohydrate-Binding Modules of AMP-Activated Protein Kinase. Chembiochem 2018; 19:229-238. [PMID: 29193585 DOI: 10.1002/cbic.201700589] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Indexed: 01/24/2023]
Abstract
The β subunit of adenosine monophosphate (AMP)-activated protein kinase (AMPK), which exists as two isoforms (β1 and β2) in humans, has a carbohydrate-binding module (CBM) that interacts with glycogen. Although the β1- and β2-CBMs are structurally similar, with strictly conserved ligand-contact residues, they show different carbohydrate affinities. β2-CBM shows the strongest affinity for both branched and unbranched oligosaccharides and it has recently been shown that a Thr insertion into β2-CBM (Thr101) forms a pocket to accommodate branches. This insertion does not explain why β2-CBM binds all carbohydrates with stronger affinity. Herein, it is shown that residue 134 (Val for β2 and Thr for β1), which does not come into contact with a carbohydrate, appears to account for the affinity difference. Characterisation by NMR spectroscopy, however, suggests that mutant β2-Thr101Δ/Val134Thr differs from that of β1-CBM, and mutant β1-Thr101ins/Thr134Val differs from that of β2-CBM. Furthermore, these mutants are less stable to chemical denaturation, relative to that of wild-type β-CBMs, which confounds the affinity analyses. To support the importance of Thr101 and Val134, the ancestral CBM has been constructed. This CBM retains Thr101 and Val134, which suggests that the extant β1-CBM has a modest loss of function in carbohydrate binding. Because the ancestor bound carbohydrate with equal affinity to that of β2-CBM, it is concluded that residue 134 plays an indirect role in carbohydrate binding.
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Affiliation(s)
- Jesse I Mobbs
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Victoria, 3010, Australia.,Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria, 3010, Australia.,Current Address: Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Monash University, Clayton, Victoria, 3800, Australia
| | - Alex Di Paolo
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Victoria, 3010, Australia.,Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria, 3010, Australia.,Current Address: New Technologies Development Department, Kaneka Eurogentec S.A. Biologics Division, 14 Rue Bois Saint-Jean, 4102, Seraing, Belgium
| | - Riley D Metcalfe
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Victoria, 3010, Australia.,Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria, 3010, Australia
| | - Emily Selig
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Victoria, 3010, Australia.,Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria, 3010, Australia
| | - David I Stapleton
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Victoria, 3010, Australia.,Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria, 3010, Australia
| | - Michael D W Griffin
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Victoria, 3010, Australia.,Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria, 3010, Australia
| | - Paul R Gooley
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Victoria, 3010, Australia.,Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria, 3010, Australia
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13
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Nankar R, Prabhakar PK, Doble M. Hybrid drug combination: Combination of ferulic acid and metformin as anti-diabetic therapy. PHYTOMEDICINE : INTERNATIONAL JOURNAL OF PHYTOTHERAPY AND PHYTOPHARMACOLOGY 2017; 37:10-13. [PMID: 29126698 DOI: 10.1016/j.phymed.2017.10.015] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Accepted: 10/21/2017] [Indexed: 06/07/2023]
Abstract
BACKGROUND AND PURPOSE Ferulic acid, an anti-oxidant phytochemical present in several dietary components, is known to produce wide range of pharmacological effects. It is approved for use in food industry as a preservative and in sports food. Previous reports from our lab have shown synergistic interaction of ferulic acid with metformin in cell lines and diabetic rats. The purpose of this review is to compile information about anti-diabetic activity of ferulic acid in in vitro and in vivo models with special emphasis on activity of ferulic acid when combined with metformin. The mechanism of synergistic interaction between ferulic acid and metformin is also proposed after carefully studying effects of these compounds on molecules involved in glucose metabolism. METHODS Scientific literature for the purpose of this review was collected using online search engines and databases such as ScienceDirect, Scopus, PubMed and Google scholar. RESULTS Ferulic acid forms resonance stabilized phenoxyl radical which scavenges free radicals and reduce oxidative stress. It improves glucose and lipid profile in diabetic rats by enhancing activities of antioxidant enzymes, superoxide dismutase and catalase in the pancreatic tissue. Combining ferulic acid with metformin improves both, in vitro glucose uptake activity and in vivo hypoglycemic activity of the latter. It is possible to reduce the dose of metformin by four folds (from 50 to 12.5 mg/kg body weight) by combining it with 10 mg of ferulic acid/kg body weight in diabetic rats. Ferulic acid improves glucose uptake through PI3-K pathway whereas metformin activates AMPK pathway to improve glucose uptake. CONCLUSION The synergistic interaction of ferulic acid and metformin is due their action on parallel pathways which are involved in glucose uptake. Due to synergistic nature of their interaction, it is possible to reduce the dose of metformin (by combining with ferulic acid) required to achieve normoglycemia. Since the dose of metformin is reduced, the dose associated side effects of metformin therapy can be reduced.
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Affiliation(s)
- Rakesh Nankar
- Bioengineering and Drug Design Lab, Department of Biotechnology, IIT Madras, Chennai 600036, India
| | - P K Prabhakar
- Lovely Faculty of Applied Medical Sciences, LPU, Phagwara, Punjab, India
| | - Mukesh Doble
- Bioengineering and Drug Design Lab, Department of Biotechnology, IIT Madras, Chennai 600036, India.
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14
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Buisson C, Frelat C, Mongongu C, Martinat N, Audran M. Implementation of AICAR analysis by GC-C-IRMS for anti-doping purposes. Drug Test Anal 2017; 9:1704-1712. [PMID: 29032594 DOI: 10.1002/dta.2322] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Revised: 10/01/2017] [Accepted: 10/02/2017] [Indexed: 11/10/2022]
Abstract
AICAR (5-aminoimidazole-4-carboxamide-1-β-D-ribofuranoside), is a naturally occurring substance which is part to the World Anti-Doping Agency (WADA) Prohibited List. It is claimed to improve physical performance when administered as a supplement. As for other endogenous compounds such as steroids, the gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS) analysis remains an efficient tool to differentiate endogenous substances from exogenous ones. A protocol was described in the literature for the analysis of AICAR by GC-C-IRMS. The aim of the present study was to implement this protocol in our laboratory and to propose solutions to avoid the difficulties encountered. The first point discussed in this study is the derivatization step. Due to the structure of the AICAR molecule, conventional derivatization for GC-C-IRMS such as acetylation could not be applied and silylation was preferred. The improvement of the derivatives stability was achieved thanks to several derivatization conditions tested. This adjustment led to a reproducible derivatization pattern with the 3-TMS form as major derivative product. The second point discussed in this study is the diminution of extracts' background noise. Indeed, the implementation of the published protocol was not easy due to high performance liquid chromatography (HPLC) problems encountered when concentrated urine was injected into our system. Also, too many interferences in the endogenous reference compound fractions were observed. The addition of both a wash step before the HPLC purification and a HPLC purification step for the endogenous reference compound (ERC) fraction allowed us to increase the robustness of the method. This study presents the modified protocol compared to the original protocol as well as the evaluation of the whole method performances. Copyright © 2017 John Wiley & Sons, Ltd.
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Affiliation(s)
- C Buisson
- Analysis Department - Agence Française de Lutte contre le Dopage (AFLD), Châtenay-Malabry, France
| | - C Frelat
- Analysis Department - Agence Française de Lutte contre le Dopage (AFLD), Châtenay-Malabry, France
| | - C Mongongu
- Analysis Department - Agence Française de Lutte contre le Dopage (AFLD), Châtenay-Malabry, France
| | - N Martinat
- Analysis Department - Agence Française de Lutte contre le Dopage (AFLD), Châtenay-Malabry, France
| | - M Audran
- Analysis Department - Agence Française de Lutte contre le Dopage (AFLD), Châtenay-Malabry, France
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15
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Mice Deficient in lysophosphatidic acid acyltransferase delta ( Lpaatδ)/ acylglycerophosphate acyltransferase 4 ( Agpat4) Have Impaired Learning and Memory. Mol Cell Biol 2017; 37:MCB.00245-17. [PMID: 28807933 DOI: 10.1128/mcb.00245-17] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Accepted: 08/07/2017] [Indexed: 01/17/2023] Open
Abstract
We previously characterized LPAATδ/AGPAT4 as a mitochondrial lysophosphatidic acid acyltransferase that regulates brain levels of phosphatidylcholine (PC), phosphatidylethanolamine (PE), and phosphatidylinositol (PI). Here, we report that Lpaatδ-/- mice display impaired spatial learning and memory compared to wild-type littermates in the Morris water maze and our investigation of potential mechanisms associated with brain phospholipid changes. Marker protein immunoblotting suggested that the relative brain content of neurons, glia, and oligodendrocytes was unchanged. Relative abundance of the important brain fatty acid docosahexaenoic acid was also unchanged in phosphatidylserine, phosphatidylglycerol, and cardiolipin, in agreement with prior data on PC, PE and PI. In phosphatidic acid, it was increased. Specific decreases in ethanolamine-containing phospholipids were detected in mitochondrial lipids, but the function of brain mitochondria in Lpaatδ-/- mice was unchanged. Importantly, we found that Lpaatδ-/- mice have a significantly and drastically lower brain content of the N-methyl-d-asparate (NMDA) receptor subunits NR1, NR2A, and NR2B, as well as the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor subunit GluR1, compared to wild-type mice. However, general dysregulation of PI-mediated signaling is not likely responsible, since phospho-AKT and phospho-mTOR pathway regulation was unaffected. Our findings indicate that Lpaatδ deficiency causes deficits in learning and memory associated with reduced NMDA and AMPA receptors.
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16
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Dong S, Baranwal S, Garcia A, Serrano-Gomez SJ, Eastlack S, Iwakuma T, Mercante D, Mauvais-Jarvis F, Alahari SK. Nischarin inhibition alters energy metabolism by activating AMP-activated protein kinase. J Biol Chem 2017; 292:16833-16846. [PMID: 28842496 DOI: 10.1074/jbc.m117.784256] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Revised: 08/22/2017] [Indexed: 11/06/2022] Open
Abstract
Nischarin (Nisch) is a key protein functioning as a molecular scaffold and thereby hosting interactions with several protein partners. To explore the physiological importance of Nisch, here we generated Nisch loss-of-function mutant mice and analyzed their metabolic phenotype. Nisch-mutant embryos exhibited delayed development, characterized by small size and attenuated weight gain. We uncovered the reason for this phenotype by showing that Nisch binds to and inhibits the activity of AMP-activated protein kinase (AMPK), which regulates energy homeostasis by suppressing anabolic and activating catabolic processes. The Nisch mutations enhanced AMPK activation and inhibited mechanistic target of rapamycin signaling in mouse embryonic fibroblasts as well as in muscle and liver tissues of mutant mice. Nisch-mutant mice also exhibited increased rates of glucose oxidation with increased energy expenditure, despite reduced overall food intake. Moreover, the Nisch-mutant mice had reduced expression of liver markers of gluconeogenesis associated with increased glucose tolerance. As a result, these mice displayed decreased growth and body weight. Taken together, our results indicate that Nisch is an important AMPK inhibitor and a critical regulator of energy homeostasis, including lipid and glucose metabolism.
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Affiliation(s)
- Shengli Dong
- From the Department of Biochemistry and Molecular Biology, School of Medicine, and
| | - Somesh Baranwal
- From the Department of Biochemistry and Molecular Biology, School of Medicine, and.,the Center for Biochemistry and Microbial Sciences, Central University of Punjab, City Campus Mansa Rd., Bathinda-151001, India
| | - Anapatricia Garcia
- the Department of Pathology and Laboratory Medicine, Emory University, Atlanta, Georgia 30322
| | - Silvia J Serrano-Gomez
- From the Department of Biochemistry and Molecular Biology, School of Medicine, and.,the Pontificia Universidad Javeriana, 11001000 Bogotá, Colombia
| | - Steven Eastlack
- From the Department of Biochemistry and Molecular Biology, School of Medicine, and
| | - Tomoo Iwakuma
- the Department of Cancer Biology, Kansas University Medical Center, Kansas City, Kansas 66160, and
| | - Donald Mercante
- Department of Biostatistics, School of Public Health, Louisiana State University Health Science Center, New Orleans, Louisiana 70112
| | - Franck Mauvais-Jarvis
- the Division of Endocrinology, Tulane University School of Medicine, New Orleans, Louisiana 70112
| | - Suresh K Alahari
- From the Department of Biochemistry and Molecular Biology, School of Medicine, and
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17
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Shaw A, Jeromson S, Watterson KR, Pediani JD, Gallagher IJ, Whalley T, Dreczkowski G, Brooks N, Galloway SD, Hamilton DL. Multiple AMPK activators inhibit l-carnitine uptake in C2C12 skeletal muscle myotubes. Am J Physiol Cell Physiol 2017; 312:C689-C696. [PMID: 28298333 DOI: 10.1152/ajpcell.00026.2016] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Revised: 02/21/2017] [Accepted: 03/14/2017] [Indexed: 12/29/2022]
Abstract
Mutations in the gene that encodes the principal l-carnitine transporter, OCTN2, can lead to a reduced intracellular l-carnitine pool and the disease Primary Carnitine Deficiency. l-Carnitine supplementation is used therapeutically to increase intracellular l-carnitine. As AMPK and insulin regulate fat metabolism and substrate uptake, we hypothesized that AMPK-activating compounds and insulin would increase l-carnitine uptake in C2C12 myotubes. The cells express all three OCTN transporters at the mRNA level, and immunohistochemistry confirmed expression at the protein level. Contrary to our hypothesis, despite significant activation of PKB and 2DG uptake, insulin did not increase l-carnitine uptake at 100 nM. However, l-carnitine uptake was modestly increased at a dose of 150 nM insulin. A range of AMPK activators that increase intracellular calcium content [caffeine (10 mM, 5 mM, 1 mM, 0.5 mM), A23187 (10 μM)], inhibit mitochondrial function [sodium azide (75 μM), rotenone (1 μM), berberine (100 μM), DNP (500 μM)], or directly activate AMPK [AICAR (250 μM)] were assessed for their ability to regulate l-carnitine uptake. All compounds tested significantly inhibited l-carnitine uptake. Inhibition by caffeine was not dantrolene (10 μM) sensitive despite dantrolene inhibiting caffeine-mediated calcium release. Saturation curve analysis suggested that caffeine did not competitively inhibit l-carnitine transport. To assess the potential role of AMPK in this process, we assessed the ability of the AMPK inhibitor Compound C (10 μM) to rescue the effect of caffeine. Compound C offered a partial rescue of l-carnitine uptake with 0.5 mM caffeine, suggesting that AMPK may play a role in the inhibitory effects of caffeine. However, caffeine likely inhibits l-carnitine uptake by alternative mechanisms independently of calcium release. PKA activation or direct interference with transporter function may play a role.
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Affiliation(s)
- Andy Shaw
- Physiology, Exercise and Nutrition Research Group, Faculty of Health Sciences and Sport, University of Stirling, Stirling, United Kingdom
| | - Stewart Jeromson
- Physiology, Exercise and Nutrition Research Group, Faculty of Health Sciences and Sport, University of Stirling, Stirling, United Kingdom
| | - Kenneth R Watterson
- Molecular Pharmacology Group, Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom; and
| | - John D Pediani
- Molecular Pharmacology Group, Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom; and
| | - Iain J Gallagher
- Physiology, Exercise and Nutrition Research Group, Faculty of Health Sciences and Sport, University of Stirling, Stirling, United Kingdom
| | - Tim Whalley
- Biological and Environmental Sciences, School of Natural Sciences, University of Stirling, Stirling, United Kingdom
| | - Gillian Dreczkowski
- Physiology, Exercise and Nutrition Research Group, Faculty of Health Sciences and Sport, University of Stirling, Stirling, United Kingdom
| | - Naomi Brooks
- Physiology, Exercise and Nutrition Research Group, Faculty of Health Sciences and Sport, University of Stirling, Stirling, United Kingdom
| | - Stuart D Galloway
- Physiology, Exercise and Nutrition Research Group, Faculty of Health Sciences and Sport, University of Stirling, Stirling, United Kingdom
| | - D Lee Hamilton
- Physiology, Exercise and Nutrition Research Group, Faculty of Health Sciences and Sport, University of Stirling, Stirling, United Kingdom;
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18
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Martínez-Fernández L, González-Muniesa P, Laiglesia LM, Sáinz N, Prieto-Hontoria PL, Escoté X, Odriozola L, Corrales FJ, Arbones-Mainar JM, Martínez JA, Moreno-Aliaga MJ. Maresin 1 improves insulin sensitivity and attenuates adipose tissue inflammation in ob/ob and diet-induced obese mice. FASEB J 2017; 31:2135-2145. [PMID: 28188173 DOI: 10.1096/fj.201600859r] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Accepted: 01/23/2017] [Indexed: 02/06/2023]
Abstract
The beneficial actions of n-3 fatty acids on obesity-induced insulin resistance and inflammation have been related to the synthesis of specialized proresolving lipid mediators (SPMs) like resolvins. The aim of this study was to evaluate the ability of one of these SPMs, maresin 1 (MaR1), to reverse adipose tissue inflammation and/or insulin resistance in two models of obesity: diet-induced obese (DIO) mice and genetic (ob/ob) obese mice. In DIO mice, MaR1 (2 μg/kg; 10 d) reduced F4/80-positive cells and expression of the proinflammatory M1 macrophage phenotype marker Cd11c in white adipose tissue (WAT). Moreover, MaR1 decreased Mcp-1, Tnf-α, and Il-1β expression, upregulated adiponectin and Glut-4, and increased Akt phosphorylation in WAT. MaR1 administration (2 μg/kg; 20 d) to ob/ob mice did not modify macrophage recruitment but increased the M2 macrophage markers Cd163 and Il-10. MaR1 reduced Mcp-1, Tnf-α, Il-1β, and Dpp-4 and increased adiponectin gene expression in WAT. MaR1 treatment also improved the insulin tolerance test of ob/ob mice and increased Akt and AMPK phosphorylation in WAT. These data suggest that treatment with MaR1 can counteract the dysfunctional inflamed WAT and could be useful to improve insulin sensitivity in murine models of obesity.-Martínez-Fernández, L., González-Muniesa, P., Laiglesia, L. M., Sáinz, N., Prieto-Hontoria, P. L., Escoté, X., Odriozola, L., Corrales, F. J., Arbones-Mainar, J. M., Martínez, J. A., Moreno-Aliaga, M. J. Maresin 1 improves insulin sensitivity and attenuates adipose tissue inflammation in ob/ob and diet-induced obese mice.
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Affiliation(s)
- Leyre Martínez-Fernández
- Department of Nutrition, Food Science and Physiology, School of Pharmacy and Nutrition, University of Navarra, Pamplona, Spain.,Centre for Nutrition Research, School of Pharmacy and Nutrition, University of Navarra, Pamplona, Spain
| | - Pedro González-Muniesa
- Department of Nutrition, Food Science and Physiology, School of Pharmacy and Nutrition, University of Navarra, Pamplona, Spain.,Centre for Nutrition Research, School of Pharmacy and Nutrition, University of Navarra, Pamplona, Spain.,Center of Biomedical Research Network Physiopathology of Obesity and Nutrition (CIBEROBN), Madrid, Spain.,Health Research Institute of Navarra (IDISNA), Pamplona, Spain
| | - Laura M Laiglesia
- Department of Nutrition, Food Science and Physiology, School of Pharmacy and Nutrition, University of Navarra, Pamplona, Spain.,Centre for Nutrition Research, School of Pharmacy and Nutrition, University of Navarra, Pamplona, Spain
| | - Neira Sáinz
- Centre for Nutrition Research, School of Pharmacy and Nutrition, University of Navarra, Pamplona, Spain
| | - Pedro L Prieto-Hontoria
- Department of Nutrition, Food Science and Physiology, School of Pharmacy and Nutrition, University of Navarra, Pamplona, Spain
| | - Xavier Escoté
- Centre for Nutrition Research, School of Pharmacy and Nutrition, University of Navarra, Pamplona, Spain
| | | | - Fernando J Corrales
- Proteomics and Bioinformatics Unit, Center.,Division of Hepatology, Center for Applied Medical Research, University of Navarra, Pamplona, Spain
| | - Jose M Arbones-Mainar
- Center of Biomedical Research Network Physiopathology of Obesity and Nutrition (CIBEROBN), Madrid, Spain.,Adipocyte and Fat Biology Laboratory (AdipoFat), Instituto de Investigacion Sanitaria Aragon, Instituto Aragonés de Ciencias de la Salud, Unidad de Investigación Traslacional, Hospital Universitario Miguel Servet, Zaragoza, Spain
| | - José A Martínez
- Department of Nutrition, Food Science and Physiology, School of Pharmacy and Nutrition, University of Navarra, Pamplona, Spain.,Centre for Nutrition Research, School of Pharmacy and Nutrition, University of Navarra, Pamplona, Spain.,Center of Biomedical Research Network Physiopathology of Obesity and Nutrition (CIBEROBN), Madrid, Spain.,Health Research Institute of Navarra (IDISNA), Pamplona, Spain
| | - María J Moreno-Aliaga
- Department of Nutrition, Food Science and Physiology, School of Pharmacy and Nutrition, University of Navarra, Pamplona, Spain; .,Centre for Nutrition Research, School of Pharmacy and Nutrition, University of Navarra, Pamplona, Spain.,Center of Biomedical Research Network Physiopathology of Obesity and Nutrition (CIBEROBN), Madrid, Spain.,Health Research Institute of Navarra (IDISNA), Pamplona, Spain
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19
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Jiao R, Lobanova L, Waldner A, Fu A, Xiao L, Harkness TA, Arnason TG. The ubiquitin-conjugating enzyme, Ubc1, indirectly regulates SNF1 kinase activity via Forkhead-dependent transcription. MICROBIAL CELL 2016; 3:540-553. [PMID: 28357323 PMCID: PMC5349210 DOI: 10.15698/mic2016.11.538] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The SNF1 kinase in Saccharomyces cerevisiae is an excellent model to study the regulation and function of the AMP-dependent protein kinase (AMPK) family of serine-threonine protein kinases. Yeast discoveries regarding the regulation of this non-hormonal sensor of metabolic/environmental stress are conserved in higher eukaryotes, including poly-ubiquitination of the α-subunit of yeast (Snf1) and human (AMPKα) that ultimately effects subunit stability and enzyme activity. The ubiquitin-cascade enzymes responsible for targeting Snf1 remain unknown, leading us to screen for those that impact SNF1 kinase function. We identified the E2, Ubc1, as a regulator of SNF1 kinase function. The decreased Snf1 abundance found upon deletion of Ubc1 is not due to increased degradation, but instead is partly due to impaired SNF1 gene expression, arising from diminished abundance of the Forkhead 1/2 proteins, previously shown to contribute to SNF1 transcription. Ultimately, we report that the Fkh1/2 cognate transcription factor, Hcm1, fails to enter the nucleus in the absence of Ubc1. This implies that Ubc1 acts indirectly through transcriptional effects to modulate SNF1 kinase activity.
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Affiliation(s)
- Rubin Jiao
- Department of Anatomy and Cell Biology, University of Saskatchewan, Saskatoon, SK, Canada S7N 5E5
| | - Liubov Lobanova
- Department of Anatomy and Cell Biology, University of Saskatchewan, Saskatoon, SK, Canada S7N 5E5
| | - Amanda Waldner
- Department of Anatomy and Cell Biology, University of Saskatchewan, Saskatoon, SK, Canada S7N 5E5
| | - Anthony Fu
- Department of Anatomy and Cell Biology, University of Saskatchewan, Saskatoon, SK, Canada S7N 5E5
| | - Linda Xiao
- Department of Anatomy and Cell Biology, University of Saskatchewan, Saskatoon, SK, Canada S7N 5E5
| | - Troy A Harkness
- Department of Anatomy and Cell Biology, University of Saskatchewan, Saskatoon, SK, Canada S7N 5E5
| | - Terra G Arnason
- Department of Anatomy and Cell Biology, University of Saskatchewan, Saskatoon, SK, Canada S7N 5E5. ; Department of Medicine, University of Saskatchewan, Saskatoon, SK, Canada S7N 5E5
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20
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Acute Exercise Improves Insulin Clearance and Increases the Expression of Insulin-Degrading Enzyme in the Liver and Skeletal Muscle of Swiss Mice. PLoS One 2016; 11:e0160239. [PMID: 27467214 PMCID: PMC4965115 DOI: 10.1371/journal.pone.0160239] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Accepted: 07/15/2016] [Indexed: 11/19/2022] Open
Abstract
The effects of exercise on insulin clearance and IDE expression are not yet fully elucidated. Here, we have explored the effect of acute exercise on insulin clearance and IDE expression in lean mice. Male Swiss mice were subjected to a single bout of exercise on a speed/angle controlled treadmill for 3-h at approximately 60-70% of maximum oxygen consumption. As expected, acute exercise reduced glycemia and insulinemia, and increased insulin tolerance. The activity of AMPK-ACC, but not of IR-Akt, pathway was increased in the liver and skeletal muscle of trained mice. In an apparent contrast to the reduced insulinemia, glucose-stimulated insulin secretion was increased in isolated islets of these mice. However, insulin clearance was increased after acute exercise and was accompanied by increased expression of the insulin-degrading enzyme (IDE), in the liver and skeletal muscle. Finally, C2C12, but not HEPG2 cells, incubated at different concentrations of 5-aminoimidazole-4-carboxamide-1-β-d-ribofuranoside (AICAR) for 3-h, showed increased expression of IDE. In conclusion, acute exercise increases insulin clearance, probably due to an augmentation of IDE expression in the liver and skeletal muscle. The elevated IDE expression, in the skeletal muscle, seems to be mediated by activation of AMPK-ACC pathway, in response to exercise. We believe that the increase in the IDE expression, comprise a safety measure to maintain glycemia at or close to physiological levels, turning physical exercise more effective and safe.
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21
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Loyd C, Magrisso IJ, Haas M, Balusu S, Krishna R, Itoh N, Sandoval DA, Perez-Tilve D, Obici S, Habegger KM. Fibroblast growth factor 21 is required for beneficial effects of exercise during chronic high-fat feeding. J Appl Physiol (1985) 2016; 121:687-98. [PMID: 27445299 DOI: 10.1152/japplphysiol.00456.2016] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Accepted: 07/15/2016] [Indexed: 01/14/2023] Open
Abstract
Exercise is an effective therapy against the metabolic syndrome. However, the molecular pathways underlying the advantageous effects of exercise are elusive. Glucagon receptor signaling is essential for exercise benefits, and recent evidence indicates that a downstream effector of glucagon, fibroblast growth factor 21 (FGF21), is implicated in this response. Therefore, we tested the hypothesis that FGF21 action is necessary in mediating metabolic effects of exercise. We utilized acute exhaustive treadmill exercise in Wistar rats to identify a putative, concomitant increase in plasma glucagon and FGF21 with the increase in glucose and lactate following exercise. To test the necessity of FGF21 action in the exercise response, we exposed FGF21 congenitally deficient mice (Fgf21(-/-)) and their wild-type (Wt) littermates to chronic high-fat (HF) feeding and inoperable (sedentary) or operable (exercise) voluntary running wheels. Physiological tests were performed to assess the role of FGF21 in the beneficial effect of exercise on glucose metabolism. Wt and Fgf21(-/-) littermates exhibited similar running behavior, and exercise was effective in suppressing weight and fat mass gain and dyslipidemia independently of genotype. However, exercise failed to positively affect hepatic triglyceride content and glucose tolerance in HF diet-fed Fgf21(-/-) mice. Furthermore, Fgf21(-/-) mice exhibited an impaired adaptation to exercise training, including reduced AMP-activated protein kinase activity in skeletal muscle. This study demonstrates that FGF21 action is necessary to achieve the full metabolic benefits of exercise during chronic HF feeding.
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Affiliation(s)
- Christine Loyd
- Comprehensive Diabetes Center and Department of Medicine, Division of Endocrinology, Diabetes & and Metabolism, University of Alabama at Birmingham, Birmingham, Alabama; Metabolic Disease Institute, Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Cincinnati, Cincinnati, Ohio
| | - I Jack Magrisso
- Metabolic Disease Institute, Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Cincinnati, Cincinnati, Ohio
| | - Michael Haas
- Metabolic Disease Institute, Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Cincinnati, Cincinnati, Ohio
| | - Sowmya Balusu
- Metabolic Disease Institute, Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Cincinnati, Cincinnati, Ohio
| | - Radha Krishna
- Metabolic Disease Institute, Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Cincinnati, Cincinnati, Ohio
| | - Nobuyuki Itoh
- Department of Genetic Biochemistry, Kyoto University Graduate School of Pharmaceutical Sciences, Kyoto, Japan
| | - Darleen A Sandoval
- Metabolic Disease Institute, Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Cincinnati, Cincinnati, Ohio
| | - Diego Perez-Tilve
- Metabolic Disease Institute, Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Cincinnati, Cincinnati, Ohio
| | - Silvana Obici
- Metabolic Disease Institute, Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Cincinnati, Cincinnati, Ohio
| | - Kirk M Habegger
- Comprehensive Diabetes Center and Department of Medicine, Division of Endocrinology, Diabetes & and Metabolism, University of Alabama at Birmingham, Birmingham, Alabama; UAB Center for Exercise Medicine, University of Alabama at Birmingham, Birmingham, Alabama;
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22
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Mai TL, Hu GM, Chen CM. Visualizing and Clustering Protein Similarity Networks: Sequences, Structures, and Functions. J Proteome Res 2016; 15:2123-31. [PMID: 27267620 DOI: 10.1021/acs.jproteome.5b01031] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Research in the recent decade has demonstrated the usefulness of protein network knowledge in furthering the study of molecular evolution of proteins, understanding the robustness of cells to perturbation, and annotating new protein functions. In this study, we aimed to provide a general clustering approach to visualize the sequence-structure-function relationship of protein networks, and investigate possible causes for inconsistency in the protein classifications based on sequences, structures, and functions. Such visualization of protein networks could facilitate our understanding of the overall relationship among proteins and help researchers comprehend various protein databases. As a demonstration, we clustered 1437 enzymes by their sequences and structures using the minimum span clustering (MSC) method. The general structure of this protein network was delineated at two clustering resolutions, and the second level MSC clustering was found to be highly similar to existing enzyme classifications. The clustering of these enzymes based on sequence, structure, and function information is consistent with each other. For proteases, the Jaccard's similarity coefficient is 0.86 between sequence and function classifications, 0.82 between sequence and structure classifications, and 0.78 between structure and function classifications. From our clustering results, we discussed possible examples of divergent evolution and convergent evolution of enzymes. Our clustering approach provides a panoramic view of the sequence-structure-function network of proteins, helps visualize the relation between related proteins intuitively, and is useful in predicting the structure and function of newly determined protein sequences.
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Affiliation(s)
- Te-Lun Mai
- Department of Physics, National Taiwan Normal University , Taipei, Taiwan
| | - Geng-Ming Hu
- Department of Physics, National Taiwan Normal University , Taipei, Taiwan
| | - Chi-Ming Chen
- Department of Physics, National Taiwan Normal University , Taipei, Taiwan
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23
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Koh HJ. Regulation of exercise-stimulated glucose uptake in skeletal muscle. Ann Pediatr Endocrinol Metab 2016; 21:61-5. [PMID: 27462580 PMCID: PMC4960015 DOI: 10.6065/apem.2016.21.2.61] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Accepted: 06/26/2016] [Indexed: 11/20/2022] Open
Abstract
AMP-activated protein kinase (AMPK) is a Ser/Thr kinase that has been thought to be an important mediator for exercise-stimulated glucose uptake in skeletal muscle. Liver kinase B1 (LKB1) is an upstream kinase for AMPK and AMPK-related protein kinases, of which the function in skeletal muscle has not been well documented. Our group and others have generated mice lacking AMPK activity in skeletal muscle, as well as muscle-specific LKB1 knockout mice. In this review, we discuss the potential role of AMPK and LKB1 in regulating exercise-stimulated glucose uptake in skeletal muscle. We also discuss our recent study, demonstrating the molecular mechanism of obesity-induced development of skeletal muscle insulin resistance.
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Affiliation(s)
- Ho-Jin Koh
- Applied Physiology Division, Department of Exercise Science, Arnold School of Public Health, Univer sity of South Carolina, Columbia, SC, USA
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24
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Fortifying the Treatment of Prostate Cancer with Physical Activity. Prostate Cancer 2016; 2016:9462975. [PMID: 26977321 PMCID: PMC4764749 DOI: 10.1155/2016/9462975] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Revised: 01/06/2016] [Accepted: 01/11/2016] [Indexed: 11/18/2022] Open
Abstract
Over the past decade, significant data have shown that obese men experience a survival detriment after treatment for prostate cancer. While methods to combat obesity are of utmost importance for the prostate cancer patient, newer data reveal the overall metabolic improvements that accompany increased activity levels and intense exercise beyond weight loss. Along these lines, a plethora of data have shown improvement in prostate cancer-specific outcomes after treatment accompanied with these activity levels. This review discusses the metabolic mechanisms in which increased activity levels and exercise can help improve both outcomes for men treated for prostate cancer while lowering the side effects of treatment.
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25
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Kim N, Lee JO, Lee HJ, Lee YW, Kim HI, Kim SJ, Park SH, Lee CS, Ryoo SW, Hwang GS, Kim HS. AMPK, a metabolic sensor, is involved in isoeugenol-induced glucose uptake in muscle cells. J Endocrinol 2016; 228:105-14. [PMID: 26585419 PMCID: PMC4705517 DOI: 10.1530/joe-15-0302] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/19/2015] [Indexed: 01/07/2023]
Abstract
Isoeugenol exerts various beneficial effects on human health. However, the mechanisms underlying these effects are poorly understood. In this study, we observed that isoeugenol activated AMP-activated protein kinase (AMPK) and increased glucose uptake in rat L6 myotubes. Isoeugenol-induced increase in intracellular calcium concentration and glucose uptake was inhibited by STO-609, an inhibitor of calcium/calmodulin-dependent protein kinase kinase (CaMKK). Isoeugenol also increased the phosphorylation of protein kinase C-α (PKCα). Chelation of calcium with BAPTA-AM blocked isoeugenol-induced AMPK phosphorylation and glucose uptake. Isoeugenol stimulated p38MAPK phosphorylation that was inhibited after pretreatment with compound C, an AMPK inhibitor. Isoeugenol also increased glucose transporter type 4 (GLUT4) expression and its translocation to the plasma membrane. GLUT4 translocation was not observed after the inhibition of AMPK and CaMKK. In addition, isoeugenol activated the Akt substrate 160 (AS160) pathway, which is downstream of the p38MAPK pathway. Knockdown of the gene encoding AS160 inhibited isoeugenol-induced glucose uptake. Together, these results indicate that isoeugenol exerts beneficial health effects by activating the AMPK/p38MAPK/AS160 pathways in skeletal muscle.
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Affiliation(s)
- Nami Kim
- Department of AnatomyKorea University College of Medicine, Seoul 136-701, South KoreaDepartment of MedicineKorea University College of Medicine, Seoul, South KoreaIntegrated Metabolomics Research GroupKorea Basic Science Institute (KBSI), Western Seoul Center, Seoul, South KoreaDepartment of Life ScienceEwha Womans University, Seoul, South Korea Department of AnatomyKorea University College of Medicine, Seoul 136-701, South KoreaDepartment of MedicineKorea University College of Medicine, Seoul, South KoreaIntegrated Metabolomics Research GroupKorea Basic Science Institute (KBSI), Western Seoul Center, Seoul, South KoreaDepartment of Life ScienceEwha Womans University, Seoul, South Korea
| | - Jung Ok Lee
- Department of AnatomyKorea University College of Medicine, Seoul 136-701, South KoreaDepartment of MedicineKorea University College of Medicine, Seoul, South KoreaIntegrated Metabolomics Research GroupKorea Basic Science Institute (KBSI), Western Seoul Center, Seoul, South KoreaDepartment of Life ScienceEwha Womans University, Seoul, South Korea
| | - Hye Jeong Lee
- Department of AnatomyKorea University College of Medicine, Seoul 136-701, South KoreaDepartment of MedicineKorea University College of Medicine, Seoul, South KoreaIntegrated Metabolomics Research GroupKorea Basic Science Institute (KBSI), Western Seoul Center, Seoul, South KoreaDepartment of Life ScienceEwha Womans University, Seoul, South Korea
| | - Yong Woo Lee
- Department of AnatomyKorea University College of Medicine, Seoul 136-701, South KoreaDepartment of MedicineKorea University College of Medicine, Seoul, South KoreaIntegrated Metabolomics Research GroupKorea Basic Science Institute (KBSI), Western Seoul Center, Seoul, South KoreaDepartment of Life ScienceEwha Womans University, Seoul, South Korea
| | - Hyung Ip Kim
- Department of AnatomyKorea University College of Medicine, Seoul 136-701, South KoreaDepartment of MedicineKorea University College of Medicine, Seoul, South KoreaIntegrated Metabolomics Research GroupKorea Basic Science Institute (KBSI), Western Seoul Center, Seoul, South KoreaDepartment of Life ScienceEwha Womans University, Seoul, South Korea
| | - Su Jin Kim
- Department of AnatomyKorea University College of Medicine, Seoul 136-701, South KoreaDepartment of MedicineKorea University College of Medicine, Seoul, South KoreaIntegrated Metabolomics Research GroupKorea Basic Science Institute (KBSI), Western Seoul Center, Seoul, South KoreaDepartment of Life ScienceEwha Womans University, Seoul, South Korea
| | - Sun Hwa Park
- Department of AnatomyKorea University College of Medicine, Seoul 136-701, South KoreaDepartment of MedicineKorea University College of Medicine, Seoul, South KoreaIntegrated Metabolomics Research GroupKorea Basic Science Institute (KBSI), Western Seoul Center, Seoul, South KoreaDepartment of Life ScienceEwha Womans University, Seoul, South Korea
| | - Chul Su Lee
- Department of AnatomyKorea University College of Medicine, Seoul 136-701, South KoreaDepartment of MedicineKorea University College of Medicine, Seoul, South KoreaIntegrated Metabolomics Research GroupKorea Basic Science Institute (KBSI), Western Seoul Center, Seoul, South KoreaDepartment of Life ScienceEwha Womans University, Seoul, South Korea
| | - Sun Woo Ryoo
- Department of AnatomyKorea University College of Medicine, Seoul 136-701, South KoreaDepartment of MedicineKorea University College of Medicine, Seoul, South KoreaIntegrated Metabolomics Research GroupKorea Basic Science Institute (KBSI), Western Seoul Center, Seoul, South KoreaDepartment of Life ScienceEwha Womans University, Seoul, South Korea
| | - Geum-Sook Hwang
- Department of AnatomyKorea University College of Medicine, Seoul 136-701, South KoreaDepartment of MedicineKorea University College of Medicine, Seoul, South KoreaIntegrated Metabolomics Research GroupKorea Basic Science Institute (KBSI), Western Seoul Center, Seoul, South KoreaDepartment of Life ScienceEwha Womans University, Seoul, South Korea Department of AnatomyKorea University College of Medicine, Seoul 136-701, South KoreaDepartment of MedicineKorea University College of Medicine, Seoul, South KoreaIntegrated Metabolomics Research GroupKorea Basic Science Institute (KBSI), Western Seoul Center, Seoul, South KoreaDepartment of Life ScienceEwha Womans University, Seoul, South Korea
| | - Hyeon Soo Kim
- Department of AnatomyKorea University College of Medicine, Seoul 136-701, South KoreaDepartment of MedicineKorea University College of Medicine, Seoul, South KoreaIntegrated Metabolomics Research GroupKorea Basic Science Institute (KBSI), Western Seoul Center, Seoul, South KoreaDepartment of Life ScienceEwha Womans University, Seoul, South Korea
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Schönke M, Myers MG, Zierath JR, Björnholm M. Skeletal muscle AMP-activated protein kinase γ1(H151R) overexpression enhances whole body energy homeostasis and insulin sensitivity. Am J Physiol Endocrinol Metab 2015; 309:E679-90. [PMID: 26306597 PMCID: PMC4593773 DOI: 10.1152/ajpendo.00195.2015] [Citation(s) in RCA: 12] [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] [Received: 04/21/2015] [Accepted: 08/12/2015] [Indexed: 11/22/2022]
Abstract
AMP-activated protein kinase (AMPK) is a major sensor of energy homeostasis and stimulates ATP-generating processes such as lipid oxidation and glycolysis in peripheral tissues. The heterotrimeric enzyme consists of a catalytic α-subunit, a β-subunit that is important for enzyme activity, and a noncatalytic γ-subunit that binds AMP and activates the AMPK complex. We generated a skeletal muscle Cre-inducible transgenic mouse model expressing a mutant γ1-subunit (AMPKγ1(H151R)), resulting in chronic AMPK activation. The expression of the predominant AMPKγ3 isoform in skeletal muscle was reduced in extensor digitorum longus (EDL) muscle (81-83%) of AMPKγ1(H151R) transgenic mice, whereas the abundance and phosphorylation of the AMPK target acetyl-CoA carboxylase was increased in tibialis anterior muscle. Glycogen content was increased 10-fold in gastrocnemius muscle. Whole body carbohydrate oxidation was increased by 11%, and whereas glucose tolerance was unaffected, insulin sensitivity was increased in AMPKγ1(H151R) transgenic mice. Furthermore, perigonadal white adipose tissue mass and serum leptin were reduced in female AMPKγ1(H151R) transgenic mice by 38 and 51% respectively. Conversely, in male AMPKγ1(H151R) transgenic mice, food intake was increased (14%), but body weight and body composition were unaltered, presumably because of increased energy expenditure. In conclusion, transgenic activation of skeletal muscle AMPKγ1 in this model plays an important sex-specific role in skeletal muscle metabolism and whole body energy homeostasis.
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Affiliation(s)
- Milena Schönke
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
| | - Martin G Myers
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan; and
| | - Juleen R Zierath
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden; Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Marie Björnholm
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden;
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Bradley EA, Zhang L, Genders AJ, Richards SM, Rattigan S, Keske MA. Enhancement of insulin-mediated rat muscle glucose uptake and microvascular perfusion by 5-aminoimidazole-4-carboxamide-1-β-D-ribofuranoside. Cardiovasc Diabetol 2015; 14:91. [PMID: 26194188 PMCID: PMC4509722 DOI: 10.1186/s12933-015-0251-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Accepted: 06/30/2015] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Insulin-induced microvascular recruitment is important for optimal muscle glucose uptake. 5-aminoimidazole-4-carboxamide-1-β-D-ribofuranoside (AICAR, an activator of AMP-activated protein kinase), can also induce microvascular recruitment, at doses that do not acutely activate glucose transport in rat muscle. Whether low doses of AICAR can augment physiologic insulin action is unknown. In the present study we used the euglycemic hyperinsulinemic clamp to assess whether insulin action is augmented by low dose AICAR. METHODS Anesthetized rats were studied during saline infusion or euglycemic insulin (3 mU/kg/min) clamp for 2 h in the absence or presence of AICAR for the last hour (5 mg bolus followed by 3.75 mg/kg/min). Muscle glucose uptake (R'g) was determined radioisotopically with (14)C-2-deoxyglucose and muscle microvascular perfusion by contrast-enhanced ultrasound with microbubbles. RESULTS AICAR did not affect blood glucose, or lower leg R'g, although it significantly (p < 0.05) increased blood lactate levels and augmented muscle microvascular blood volume via a nitric oxide synthase dependent pathway. Insulin increased femoral blood flow, whole body glucose infusion rate (GIR), R'g, hindleg glucose uptake, and microvascular blood volume. Addition of AICAR during insulin infusion increased lactate production, further increased R'g in Type IIA (fast twitch oxidative) and IIB (fast twitch glycolytic) fiber containing muscles, and hindleg glucose uptake, but decreased R'g in the Type I (slow twitch oxidative) fiber muscle. AICAR also decreased GIR due to inhibition of insulin-mediated suppression of hepatic glucose output. AICAR augmented insulin-mediated microvascular perfusion. CONCLUSIONS AICAR, at levels that have no direct effect on muscle glucose uptake, augments insulin-mediated microvascular blood flow and glucose uptake in white fiber type muscles. Agents targeted to endothelial AMPK activation are promising insulin sensitizers, however, the decrease in GIR and the propensity to increase blood lactate cautions against AICAR as an acute insulin sensitizer.
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Affiliation(s)
- Eloise A Bradley
- Menzies Institute for Medical Research, University of Tasmania, Private Bag 23, Hobart, 7001, TAS, Australia.
| | - Lei Zhang
- Garvan Institute of Medical Research, Darlinghurst, NSW, Australia.
| | - Amanda J Genders
- Institute of Sport, Exercise and Active Living (ISEAL), Victoria University, Melbourne, VIC, Australia.
| | | | - Stephen Rattigan
- Menzies Institute for Medical Research, University of Tasmania, Private Bag 23, Hobart, 7001, TAS, Australia.
| | - Michelle A Keske
- Menzies Institute for Medical Research, University of Tasmania, Private Bag 23, Hobart, 7001, TAS, Australia.
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Is 5´-AMP-Activated Protein Kinase Both Jekyll and Hyde in Bladder Cancer? Int Neurourol J 2015; 19:55-66. [PMID: 26126434 PMCID: PMC4490316 DOI: 10.5213/inj.2015.19.2.55] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2015] [Accepted: 05/18/2015] [Indexed: 12/21/2022] Open
Abstract
The 5´-AMP-activated protein kinase (AMPK) is a key regulator of cellular metabolism and energy homeostasis in mammalian tissues. Metabolic adaptation is a critical step in ensuring cell survival during metabolic stress. Because of its critical role in the regulation of glucose homeostasis and carbohydrate, lipid, and protein metabolism, AMPK is involved in many human diseases, including cancers. Although AMPK signaling was originally characterized as a tumor-suppressive signaling pathway, several lines of evidence suggest that AMPK plays a much broader role and cannot simply be defined as either an oncogenic regulator or tumor suppressor. Notably, several recent studies demonstrated that the antitumorigenic effects of many indirect AMPK activators, such as metformin, do not depend on AMPK. Conversely, activation of AMPK induces the progression of cancers, emphasizing its oncogenic effect. Bladder cancer can be divided into two groups: non–muscle-invasive bladder cancer (NMIBC) and muscle-invasive bladder cancer (MIBC). The molecular mechanisms underlying these two types of cancer are distinct: NMIBC is associated with activation of the Ras pathway, whereas MIBC is characterized by loss of major tumor suppressors. Importantly, both pathways are connected to the mammalian target of rapamycin (mTOR) pathway. In addition, our recent metabolomic findings suggest that β-oxidation of fatty acids is an important factor in the development of bladder cancer. Both mTOR and β-oxidation are tightly associated with the AMPK pathway. Here, I summarize and discuss the recent findings on the two distinct roles of AMPK in cancer, as well as the relationship between bladder cancer and AMPK.
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Rana S, Blowers EC, Natarajan A. Small molecule adenosine 5'-monophosphate activated protein kinase (AMPK) modulators and human diseases. J Med Chem 2014; 58:2-29. [PMID: 25122135 DOI: 10.1021/jm401994c] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Adenosine 5'-monophosphate activated protein kinase (AMPK) is a master sensor of cellular energy status that plays a key role in the regulation of whole-body energy homeostasis. AMPK is a serine/threonine kinase that is activated by upstream kinases LKB1, CaMKKβ, and Tak1, among others. AMPK exists as αβγ trimeric complexes that are allosterically regulated by AMP, ADP, and ATP. Dysregulation of AMPK has been implicated in a number of metabolic diseases including type 2 diabetes mellitus and obesity. Recent studies have associated roles of AMPK with the development of cancer and neurological disorders, making it a potential therapeutic target to treat human diseases. This review focuses on the structure and function of AMPK, its role in human diseases, and its direct substrates and provides a brief synopsis of key AMPK modulators and their relevance in human diseases.
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Affiliation(s)
- Sandeep Rana
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center , Omaha, Nebraska 68198-6805, United States
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30
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Role of AMPK α in skeletal muscle glycometabolism regulation and adaptation in relation to sepsis. BIOMED RESEARCH INTERNATIONAL 2014; 2014:390760. [PMID: 25097857 PMCID: PMC4100375 DOI: 10.1155/2014/390760] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Accepted: 06/16/2014] [Indexed: 12/19/2022]
Abstract
Background. AMP-activated protein kinase (AMPK) and the translocation of glucose transporter 4 (GLUT4) protein always involve disturbance of carbohydrate metabolism. Objective. To determine whether the change of blood glucose in the early stage of septic rat is associated with the alteration of AMPKα protein expression and GLUT4 protein translocation expression. Methods. Animal models of sepsis were induced by tail vein injection of LPS in Wistar rats. The dynamic values of blood glucose within 2 hours after injection of LPS were observed. AMPKα protein and GLUT4 protein translocation in different tissues (such as soleus muscle and extensor digitorum longus) were assessed by western blot.
Results. Blood glucose levels appeared to rise at 0.5 h after injection of LPS, arrived the peak value at 1 h, then fell at 1.5 h and 2 h Animals in LPS group experienced the increase of phos-AMPKα protein and GLUT4 protein translocation expression in soleus muscle and extensor digitorum longus. Conclusion. The dynamic change of blood glucose, represented in a form of initiative increase and subsequent decrease in the early stage of sepsis, may be related to glycometabolism disorder in the skeletal muscle, coming down to enhancement of GLUT4 translocation expression promoted by activation of AMPKα.
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Hasenour CM, Ridley DE, Hughey CC, James FD, Donahue EP, Shearer J, Viollet B, Foretz M, Wasserman DH. 5-Aminoimidazole-4-carboxamide-1-β-D-ribofuranoside (AICAR) effect on glucose production, but not energy metabolism, is independent of hepatic AMPK in vivo. J Biol Chem 2014; 289:5950-9. [PMID: 24403081 DOI: 10.1074/jbc.m113.528232] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Metabolic stress, as well as several antidiabetic agents, increases hepatic nucleotide monophosphate (NMP) levels, activates AMP-activated protein kinase (AMPK), and suppresses glucose production. We tested the necessity of hepatic AMPK for the in vivo effects of an acute elevation in NMP on metabolism. 5-Aminoimidazole-4-carboxamide 1-β-D-ribofuranoside (AICAR; 8 mg·kg(-1)·min(-1))-euglycemic clamps were performed to elicit an increase in NMP in wild type (α1α2(lox/lox)) and liver-specific AMPK knock-out mice (α1α2(lox/lox) + Albcre) in the presence of fixed glucose. Glucose kinetics were equivalent in 5-h fasted α1α2(lox/lox) and α1α2(lox/lox) + Albcre mice. AMPK was not required for AICAR-mediated suppression of glucose production and increased glucose disappearance. These results demonstrate that AMPK is unnecessary for normal 5-h fasting glucose kinetics and AICAR-mediated inhibition of glucose production. Moreover, plasma fatty acids and triglycerides also decreased independently of hepatic AMPK during AICAR administration. Although the glucoregulatory effects of AICAR were shown to be independent of AMPK, these studies provide in vivo support for the AMPK energy sensor paradigm. AICAR reduced hepatic energy charge by ∼20% in α1α2(lox/lox), which was exacerbated by ∼2-fold in α1α2(lox/lox) + Albcre. This corresponded to a ∼6-fold rise in AMP/ATP in α1α2(lox/lox) + Albcre. Consistent with the effects on adenine nucleotides, maximal mitochondrial respiration was ∼30% lower in α1α2(lox/lox) + Albcre than α1α2(lox/lox) livers. Mitochondrial oxidative phosphorylation efficiency was reduced by 25%. In summary, these results demonstrate that the NMP capacity to inhibit glucose production in vivo is independent of liver AMPK. In contrast, AMPK promotes mitochondrial function and protects against a more precipitous fall in ATP during AICAR administration.
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Mackenzie RWA, Elliott BT. Akt/PKB activation and insulin signaling: a novel insulin signaling pathway in the treatment of type 2 diabetes. Diabetes Metab Syndr Obes 2014; 7:55-64. [PMID: 24611020 PMCID: PMC3928478 DOI: 10.2147/dmso.s48260] [Citation(s) in RCA: 202] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Type 2 diabetes is a metabolic disease categorized primarily by reduced insulin sensitivity, β-cell dysfunction, and elevated hepatic glucose production. Treatments reducing hyperglycemia and the secondary complications that result from these dysfunctions are being sought after. Two distinct pathways encourage glucose transport activity in skeletal muscle, ie, the contraction-stimulated pathway reliant on Ca(2+)/5'-monophosphate-activated protein kinase (AMPK)-dependent mechanisms and an insulin-dependent pathway activated via upregulation of serine/threonine protein kinase Akt/PKB. Metformin is an established treatment for type 2 diabetes due to its ability to increase peripheral glucose uptake while reducing hepatic glucose production in an AMPK-dependent manner. Peripheral insulin action is reduced in type 2 diabetics whereas AMPK signaling remains largely intact. This paper firstly reviews AMPK and its role in glucose uptake and then focuses on a novel mechanism known to operate via an insulin-dependent pathway. Inositol hexakisphosphate (IP6) kinase 1 (IP6K1) produces a pyrophosphate group at the position of IP6 to generate a further inositol pyrophosphate, ie, diphosphoinositol pentakisphosphate (IP7). IP7 binds with Akt/PKB at its pleckstrin homology domain, preventing interaction with phosphatidylinositol 3,4,5-trisphosphate, and therefore reducing Akt/PKB membrane translocation and insulin-stimulated glucose uptake. Novel evidence suggesting a reduction in IP7 production via IP6K1 inhibition represents an exciting therapeutic avenue in the treatment of insulin resistance. Metformin-induced activation of AMPK is a key current intervention in the management of type 2 diabetes. However, this treatment does not seem to improve peripheral insulin resistance. In light of this evidence, we suggest that inhibition of IP6K1 may increase insulin sensitivity and provide a novel research direction in the treatment of insulin resistance.
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Affiliation(s)
- Richard WA Mackenzie
- Department of Human and Health Sciences, Facility of Science and Technology, University of Westminster, London, UK
- Correspondence: Richard WA Mackenzie, Department of Human and Health Sciences, Facility of Science and Technology, University of Westminster, 115 New Cavendish St, London W1W 6UW, UK, Tel +44 020 7911 5000 ext 3811, Email
| | - Bradley T Elliott
- Department of Human and Health Sciences, Facility of Science and Technology, University of Westminster, London, UK
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Ruderman NB, Carling D, Prentki M, Cacicedo JM. AMPK, insulin resistance, and the metabolic syndrome. J Clin Invest 2013; 123:2764-72. [PMID: 23863634 DOI: 10.1172/jci67227] [Citation(s) in RCA: 602] [Impact Index Per Article: 54.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Insulin resistance (IR) and hyperinsulinemia are hallmarks of the metabolic syndrome, as are central adiposity, dyslipidemia, and a predisposition to type 2 diabetes, atherosclerotic cardiovascular disease, hypertension, and certain cancers. Regular exercise and calorie restriction have long been known to increase insulin sensitivity and decrease the prevalence of these disorders. The subsequent identification of AMP-activated protein kinase (AMPK) and its activation by exercise and fuel deprivation have led to studies of the effects of AMPK on both IR and metabolic syndrome-related diseases. In this review, we evaluate this body of literature, with special emphasis on the hypothesis that dysregulation of AMPK is both a pathogenic factor for these disorders in humans and a target for their prevention and therapy.
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Affiliation(s)
- Neil B Ruderman
- Diabetes and Metabolism Research Unit, Boston University School of Medicine, Boston, Massachusetts 02118, USA.
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Lee-Young RS, Bonner JS, Mayes WH, Iwueke I, Barrick BA, Hasenour CM, Kang L, Wasserman DH. AMP-activated protein kinase (AMPK)α2 plays a role in determining the cellular fate of glucose in insulin-resistant mouse skeletal muscle. Diabetologia 2013; 56:608-17. [PMID: 23224579 PMCID: PMC4075509 DOI: 10.1007/s00125-012-2787-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2012] [Accepted: 11/01/2012] [Indexed: 12/25/2022]
Abstract
AIMS/HYPOTHESIS We determined whether: (1) an acute lipid infusion impairs skeletal muscle AMP-activated protein kinase (AMPK)α2 activity, increases inducible nitric oxide synthase (iNOS) and causes peripheral insulin resistance in conscious, unstressed, lean mice; and (2) restoration of AMPKα2 activity during the lipid infusion attenuates the increase in iNOS and reverses the defect in insulin sensitivity in vivo. METHODS Chow-fed, 18-week-old C57BL/6J male mice were surgically catheterised. After 5 days they received: (1) a 5 h infusion of 5 ml kg(-1) h(-1) Intralipid + 6 U/h heparin (Lipid treatment) or saline (Control); (2) Lipid treatment or Control, followed by a 2 h hyperinsulinaemic-euglycaemic clamp (insulin clamp; 4 mU kg(-1) min(-1)); and (3) infusion of the AMPK activator, 5-aminoimidazole-4-carboxamide 1-β-D-ribofuranoside (AICAR) (1 mg kg(-1) min(-1)), or saline during Lipid treatment, followed by a 2 h insulin clamp. In a separate protocol, mice producing a muscle-specific kinase-dead AMPKα2 subunit (α2-KD) underwent an insulin clamp to determine the role of AMPKα2 in insulin-mediated muscle glucose metabolism. RESULTS Lipid treatment decreased AMPKα2 activity, increased iNOS abundance/activation and reduced whole-body insulin sensitivity in vivo. AICAR increased AMPKα2 activity twofold; this did not suppress iNOS or improve whole-body or tissue-specific rates of glucose uptake during Lipid treatment. AICAR caused a marked increase in insulin-mediated glycogen synthesis in skeletal muscle. Consistent with this latter result, lean α2-KD mice exhibited impaired insulin-stimulated glycogen synthesis even though muscle glucose uptake was not affected. CONCLUSIONS/INTERPRETATION Acute induction of insulin resistance via lipid infusion in healthy mice impairs AMPKα2, increases iNOS and causes insulin resistance in vivo. However, these changes do not appear to be interrelated. Rather, a functionally active AMPKα2 subunit is required for insulin-stimulated muscle glycogen synthesis.
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Affiliation(s)
- R S Lee-Young
- Cellular and Molecular Metabolism Laboratory, Division of Metabolism and Obesity, Baker IDI Heart and Diabetes Institute, 75 Commercial Rd, Melbourne, VIC 3004, Australia.
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Srivastava RAK, Pinkosky SL, Filippov S, Hanselman JC, Cramer CT, Newton RS. AMP-activated protein kinase: an emerging drug target to regulate imbalances in lipid and carbohydrate metabolism to treat cardio-metabolic diseases. J Lipid Res 2012; 53:2490-514. [PMID: 22798688 DOI: 10.1194/jlr.r025882] [Citation(s) in RCA: 199] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The adenosine monophosphate-activated protein kinase (AMPK) is a metabolic sensor of energy metabolism at the cellular as well as whole-body level. It is activated by low energy status that triggers a switch from ATP-consuming anabolic pathways to ATP-producing catabolic pathways. AMPK is involved in a wide range of biological activities that normalizes lipid, glucose, and energy imbalances. These pathways are dysregulated in patients with metabolic syndrome (MetS), which represents a clustering of major cardiovascular risk factors including diabetes, lipid abnormalities, and energy imbalances. Clearly, there is an unmet medical need to find a molecule to treat alarming number of patients with MetS. AMPK, with multifaceted activities in various tissues, has emerged as an attractive drug target to manage lipid and glucose abnormalities and maintain energy homeostasis. A number of AMPK activators have been tested in preclinical models, but many of them have yet to reach to the clinic. This review focuses on the structure-function and role of AMPK in lipid, carbohydrate, and energy metabolism. The mode of action of AMPK activators, mechanism of anti-inflammatory activities, and preclinical and clinical findings as well as future prospects of AMPK as a drug target in treating cardio-metabolic disease are discussed.
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Sanchez AMJ, Candau RB, Csibi A, Pagano AF, Raibon A, Bernardi H. The role of AMP-activated protein kinase in the coordination of skeletal muscle turnover and energy homeostasis. Am J Physiol Cell Physiol 2012; 303:C475-85. [PMID: 22700795 DOI: 10.1152/ajpcell.00125.2012] [Citation(s) in RCA: 89] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The AMP-activated protein kinase (AMPK) is a serine/threonine protein kinase that acts as a sensor of cellular energy status switch regulating several systems including glucose and lipid metabolism. Recently, AMPK has been implicated in the control of skeletal muscle mass by decreasing mTORC1 activity and increasing protein degradation through regulation of ubiquitin-proteasome and autophagy pathways. In this review, we give an overview of the central role of AMPK in the control of skeletal muscle plasticity. We detail particularly its implication in the control of the hypertrophic and atrophic signaling pathways. In the light of these cumulative and attractive results, AMPK appears as a key player in regulating muscle homeostasis and the modulation of its activity may constitute a therapeutic potential in treating muscle wasting syndromes in humans.
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Affiliation(s)
- Anthony M J Sanchez
- INRA, UMR866 Dynamique Musculaire Et Métabolisme, 2 Place Viala, 34060 Montpellier, France.
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Turban S, Stretton C, Drouin O, Green CJ, Watson ML, Gray A, Ross F, Lantier L, Viollet B, Hardie DG, Marette A, Hundal HS. Defining the contribution of AMP-activated protein kinase (AMPK) and protein kinase C (PKC) in regulation of glucose uptake by metformin in skeletal muscle cells. J Biol Chem 2012; 287:20088-99. [PMID: 22511782 PMCID: PMC3370192 DOI: 10.1074/jbc.m111.330746] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2011] [Revised: 04/11/2012] [Indexed: 12/25/2022] Open
Abstract
The importance of AMP-activated protein kinase (AMPK) and protein kinase C (PKC) as effectors of metformin (Met) action on glucose uptake (GU) in skeletal muscle cells was investigated. GU in L6 myotubes was stimulated 2-fold following 16 h of Met treatment and acutely enhanced by insulin in an additive fashion. Insulin-stimulated GU was sensitive to PI3K inhibition, whereas that induced by Met was not. Met and its related biguanide, phenformin, stimulated AMPK activation/phosphorylation to a level comparable with that induced by the AMPK activator, 5-amino-1-β-d-ribofuranosyl-imidazole-4-carboxamide (AICAR). However, the increase in GU elicited by AICAR was significantly lower than that induced by either biguanide. Expression of a constitutively active AMPK mimicked the effects of AICAR on GU, whereas a dominant interfering AMPK or shRNA silencing of AMPK prevented AICAR-stimulated GU and Met-induced AMPK signaling but only repressed biguanide-stimulated GU by ∼20%. Consistent with this, analysis of GU in muscle cells from α1(-/-)/α2(-/-) AMPK-deficient mice revealed a significant retention of Met-stimulated GU, being reduced by ∼35% compared with that of wild type cells. Atypical PKCs (aPKCs) have been implicated in Met-stimulated GU, and in line with this, Met and phenformin induced activation/phosphorylation of aPKC in L6 myotubes. However, although cellular depletion of aPKC (>90%) led to loss in biguanide-induced aPKC phosphorylation, it had no effect on Met-stimulated GU, whereas inhibitors targeting novel/conventional PKCs caused a significant reduction in biguanide-induced GU. Our findings indicate that although Met activates AMPK, a significant component of Met-stimulated GU in muscle cells is mediated via an AMPK-independent mechanism that involves novel/conventional PKCs.
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Affiliation(s)
- Sophie Turban
- From the Division of Cell Signaling and Immunology, College of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland, United Kingdom
| | - Clare Stretton
- From the Division of Cell Signaling and Immunology, College of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland, United Kingdom
| | - Olivier Drouin
- the Department of Medicine, Québec Heart and Lung Institute, Université Laval and Metabolism, Vascular, and Renal Health Axis, Laval University Hospital Research Center, Ste-Foy, Québec, G1V 4G2, Canada
| | - Charlotte J. Green
- From the Division of Cell Signaling and Immunology, College of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland, United Kingdom
| | - Maria L. Watson
- From the Division of Cell Signaling and Immunology, College of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland, United Kingdom
| | - Alexander Gray
- From the Division of Cell Signaling and Immunology, College of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland, United Kingdom
| | - Fiona Ross
- From the Division of Cell Signaling and Immunology, College of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland, United Kingdom
| | - Louise Lantier
- INSERM, Institut Cochin, U1016, Paris, France
- CNRS, UMR8104, Paris, France, and
- Université Paris Descartes, Sorbonne Paris Cité, 75014 Paris, France
| | - Benoit Viollet
- INSERM, Institut Cochin, U1016, Paris, France
- CNRS, UMR8104, Paris, France, and
- Université Paris Descartes, Sorbonne Paris Cité, 75014 Paris, France
| | - D. Grahame Hardie
- From the Division of Cell Signaling and Immunology, College of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland, United Kingdom
| | - Andre Marette
- the Department of Medicine, Québec Heart and Lung Institute, Université Laval and Metabolism, Vascular, and Renal Health Axis, Laval University Hospital Research Center, Ste-Foy, Québec, G1V 4G2, Canada
| | - Harinder S. Hundal
- From the Division of Cell Signaling and Immunology, College of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland, United Kingdom
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Huang SL, Yu RT, Gong J, Feng Y, Dai YL, Hu F, Hu YH, Tao YD, Leng Y. Arctigenin, a natural compound, activates AMP-activated protein kinase via inhibition of mitochondria complex I and ameliorates metabolic disorders in ob/ob mice. Diabetologia 2012; 55:1469-81. [PMID: 22095235 DOI: 10.1007/s00125-011-2366-3] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2011] [Accepted: 10/06/2011] [Indexed: 12/24/2022]
Abstract
AIMS/HYPOTHESIS Arctigenin is a natural compound that had never been previously demonstrated to have a glucose-lowering effect. Here it was found to activate AMP-activated protein kinase (AMPK), and the mechanism by which this occurred, as well as the effects on glucose and lipid metabolism were investigated. METHODS 2-Deoxyglucose uptake and AMPK phosphorylation were examined in L6 myotubes and isolated skeletal muscle. Gluconeogenesis and lipid synthesis were evaluated in rat primary hepatocytes. The acute and chronic effects of arctigenin on metabolic abnormalities were observed in C57BL/6J and ob/ob mice. Changes in mitochondrial membrane potential were measured using the J-aggregate-forming dye, JC-1. Analysis of respiration of L6 myotubes or isolated mitochondria was conducted in a channel oxygen system. RESULTS Arctigenin increased AMPK phosphorylation and stimulated glucose uptake in L6 myotubes and isolated skeletal muscles. In primary hepatocytes, it decreased gluconeogenesis and lipid synthesis. The enhancement of glucose uptake and suppression of hepatic gluconeogenesis and lipid synthesis by arctigenin were prevented by blockade of AMPK activation. The respiration of L6 myotubes or isolated mitochondria was inhibited by arctigenin with a specific effect on respiratory complex I. A single oral dose of arctigenin reduced gluconeogenesis in C57BL/6J mice. Chronic oral administration of arctigenin lowered blood glucose and improved lipid metabolism in ob/ob mice. CONCLUSIONS/INTERPRETATION This study demonstrates a new role for arctigenin as a potent indirect activator of AMPK via inhibition of respiratory complex I, with beneficial effects on metabolic disorders in ob/ob mice. This highlights the potential value of arctigenin as a possible treatment of type 2 diabetes.
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Affiliation(s)
- S-L Huang
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Zu Chong Zhi Road 555, Shanghai 201203, People's Republic of China
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Magnoni LJ, Vraskou Y, Palstra AP, Planas JV. AMP-activated protein kinase plays an important evolutionary conserved role in the regulation of glucose metabolism in fish skeletal muscle cells. PLoS One 2012; 7:e31219. [PMID: 22359576 PMCID: PMC3281052 DOI: 10.1371/journal.pone.0031219] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2011] [Accepted: 01/04/2012] [Indexed: 12/16/2022] Open
Abstract
AMPK, a master metabolic switch, mediates the observed increase of glucose uptake in locomotory muscle of mammals during exercise. AMPK is activated by changes in the intracellular AMP:ATP ratio when ATP consumption is stimulated by contractile activity but also by AICAR and metformin, compounds that increase glucose transport in mammalian muscle cells. However, the possible role of AMPK in the regulation of glucose metabolism in skeletal muscle has not been investigated in other vertebrates, including fish. In this study, we investigated the effects of AMPK activators on glucose uptake, AMPK activity, cell surface levels of trout GLUT4 and expression of GLUT1 and GLUT4 as well as the expression of enzymes regulating glucose disposal and PGC1α in trout myotubes derived from a primary muscle cell culture. We show that AICAR and metformin significantly stimulated glucose uptake (1.6 and 1.3 fold, respectively) and that Compound C completely abrogated the stimulatory effects of the AMPK activators on glucose uptake. The combination of insulin and AMPK activators did not result in additive nor synergistic effects on glucose uptake. Moreover, exposure of trout myotubes to AICAR and metformin resulted in an increase in AMPK activity (3.8 and 3 fold, respectively). We also provide evidence suggesting that stimulation of glucose uptake by AMPK activators in trout myotubes may take place, at least in part, by increasing the cell surface and mRNA levels of trout GLUT4. Finally, AICAR increased the mRNA levels of genes involved in glucose disposal (hexokinase, 6-phosphofructokinase, pyruvate kinase and citrate synthase) and mitochondrial biogenesis (PGC-1α) and did not affect glycogen content or glycogen synthase mRNA levels in trout myotubes. Therefore, we provide evidence, for the first time in non-mammalian vertebrates, suggesting a potentially important role of AMPK in stimulating glucose uptake and utilization in the skeletal muscle of fish.
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Affiliation(s)
- Leonardo J. Magnoni
- Departament de Fisiologia i Immunologia, Facultat de Biologia, Universitat de Barcelona I Institut de Biomedicina de la Universitat de Barcelona (IBUB), Barcelona, Spain
| | - Yoryia Vraskou
- Departament de Fisiologia i Immunologia, Facultat de Biologia, Universitat de Barcelona I Institut de Biomedicina de la Universitat de Barcelona (IBUB), Barcelona, Spain
| | - Arjan P. Palstra
- Departament de Fisiologia i Immunologia, Facultat de Biologia, Universitat de Barcelona I Institut de Biomedicina de la Universitat de Barcelona (IBUB), Barcelona, Spain
| | - Josep V. Planas
- Departament de Fisiologia i Immunologia, Facultat de Biologia, Universitat de Barcelona I Institut de Biomedicina de la Universitat de Barcelona (IBUB), Barcelona, Spain
- * E-mail:
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Delghingaro-Augusto V, Décary S, Peyot ML, Latour MG, Lamontagne J, Paradis-Isler N, Lacharité-Lemieux M, Akakpo H, Birot O, Nolan CJ, Prentki M, Bergeron R. Voluntary running exercise prevents β-cell failure in susceptible islets of the Zucker diabetic fatty rat. Am J Physiol Endocrinol Metab 2012; 302:E254-64. [PMID: 22045312 DOI: 10.1152/ajpendo.00360.2011] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Physical activity improves glycemic control in type 2 diabetes (T2D), but its contribution to preserving β-cell function is uncertain. We evaluated the role of physical activity on β-cell secretory function and glycerolipid/fatty acid (GL/FA) cycling in male Zucker diabetic fatty (ZDF) rats. Six-week-old ZDF rats engaged in voluntary running for 6 wk (ZDF-A). Inactive Zucker lean and ZDF (ZDF-I) rats served as controls. ZDF-I rats displayed progressive hyperglycemia with β-cell failure evidenced by falling insulinemia and reduced insulin secretion to oral glucose. Isolated ZDF-I rat islets showed reduced glucose-stimulated insulin secretion expressed per islet and per islet protein. They were also characterized by loss of the glucose regulation of fatty acid oxidation and GL/FA cycling, reduced mRNA expression of key β-cell genes, and severe reduction of insulin stores. Physical activity prevented diabetes in ZDF rats through sustaining β-cell compensation to insulin resistance shown in vivo and in vitro. Surprisingly, ZDF-A islets had persistent defects in fatty acid oxidation, GL/FA cycling, and β-cell gene expression. ZDF-A islets, however, had preserved islet insulin mRNA and insulin stores compared with ZDF-I rats. Physical activity did not prevent hyperphagia, dyslipidemia, or obesity in ZDF rats. In conclusion, islets of ZDF rats have a susceptibility to failure that is possibly due to altered β-cell fatty acid metabolism. Depletion of pancreatic islet insulin stores is a major contributor to islet failure in this T2D model, preventable by physical activity.
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Affiliation(s)
- Viviane Delghingaro-Augusto
- Molecular Nutrition Unit and The Montreal Diabetes Research Center, Research Center of the University of Montreal Hospital Center,University of Montreal, Quebec, Canada
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Hao C, Hao J, Wang W, Han Z, Li G, Zhang L, Zhao X, Yu G. Insulin sensitizing effects of oligomannuronate-chromium (III) complexes in C2C12 skeletal muscle cells. PLoS One 2011; 6:e24598. [PMID: 21935427 PMCID: PMC3174176 DOI: 10.1371/journal.pone.0024598] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2011] [Accepted: 08/15/2011] [Indexed: 12/20/2022] Open
Abstract
Background It was known that the insulin resistance in skeletal muscle is a major pathogenic factor in diabetes mellitus. Therefore prevention of metabolic disorder caused by insulin resistance and improvement of insulin sensitivity are very important for the therapy of type 2 diabetes. In the present study, we investigated the ability of marine oligosaccharides oligomannuronate and its chromium (III) complexes from brown alga to enhance insulin sensitivity in C2C12 skeletal muscle cells. Methodology/Principal Findings We demonstrated that oligomannuronate, especially its chromium (III) complexes, enhanced insulin-stimulated glucose uptake and increased the mRNA expression of glucose transporter 4 (GLUT4) and insulin receptor (IR) after their internalization into C2C12 skeletal muscle cells. Additionally, oligosaccharides treatment also significantly enhanced the phosphorylation of proteins involved in both AMP activated protein kinase (AMPK)/acetyl-CoA carboxylase (ACC) and phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt) signaling pathways in C2C12 cells, indicating that the oligosaccharides activated both the insulin signal pathway and AMPK pathways as their mode of action. Moreover, oligosaccharides distributed to the mitochondria after internalization into C2C12 cells and increased the expression of transcriptional regulator peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α), carnitine palmitoyl transferase-1 (CPT-1), and phosphorylated acetyl-CoA carboxylase (p-ACC), which suggested that the actions of these oligosaccharides might be associated with mitochondria through increasing energy expenditure. All of these effects of marine oligosaccharides were comparable to that of the established anti-diabetic drug, metformin. In addition, the treatment with oligosaccharides showed less toxicity than that of metformin. Conclusions/Significance Our findings indicate that oligomannuonate and its chromium (III) complexes improved insulin sensitivity in C2C12 skeletal muscle cells, and acted as a novel glucose uptake stimulator with low toxicity, and could be used as dietary supplementary or potential drug for type 2 diabetes mellitus.
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Affiliation(s)
- Cui Hao
- Key Laboratory of Marine Drugs, Chinese Ministry of Education, Ocean University of China, Qingdao, People's Republic of China
- Shandong Provincial Key Laboratory of Glycoscience and Glycotechnology, Ocean University of China, Qingdao, People's Republic of China
| | - Jiejie Hao
- Key Laboratory of Marine Drugs, Chinese Ministry of Education, Ocean University of China, Qingdao, People's Republic of China
- Shandong Provincial Key Laboratory of Glycoscience and Glycotechnology, Ocean University of China, Qingdao, People's Republic of China
| | - Wei Wang
- Key Laboratory of Marine Drugs, Chinese Ministry of Education, Ocean University of China, Qingdao, People's Republic of China
- Shandong Provincial Key Laboratory of Glycoscience and Glycotechnology, Ocean University of China, Qingdao, People's Republic of China
| | - Zhangrun Han
- Key Laboratory of Marine Drugs, Chinese Ministry of Education, Ocean University of China, Qingdao, People's Republic of China
- Shandong Provincial Key Laboratory of Glycoscience and Glycotechnology, Ocean University of China, Qingdao, People's Republic of China
| | - Guangsheng Li
- Key Laboratory of Marine Drugs, Chinese Ministry of Education, Ocean University of China, Qingdao, People's Republic of China
- Shandong Provincial Key Laboratory of Glycoscience and Glycotechnology, Ocean University of China, Qingdao, People's Republic of China
| | - Lijuan Zhang
- Key Laboratory of Marine Drugs, Chinese Ministry of Education, Ocean University of China, Qingdao, People's Republic of China
- Shandong Provincial Key Laboratory of Glycoscience and Glycotechnology, Ocean University of China, Qingdao, People's Republic of China
| | - Xia Zhao
- Key Laboratory of Marine Drugs, Chinese Ministry of Education, Ocean University of China, Qingdao, People's Republic of China
- Shandong Provincial Key Laboratory of Glycoscience and Glycotechnology, Ocean University of China, Qingdao, People's Republic of China
| | - Guangli Yu
- Key Laboratory of Marine Drugs, Chinese Ministry of Education, Ocean University of China, Qingdao, People's Republic of China
- Shandong Provincial Key Laboratory of Glycoscience and Glycotechnology, Ocean University of China, Qingdao, People's Republic of China
- * E-mail:
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Targeted therapies of the LKB1/AMPK pathway for the treatment of insulin resistance. Future Med Chem 2011; 2:1785-96. [PMID: 21428801 DOI: 10.4155/fmc.10.264] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Type II diabetes is characterized by elevated serum glucose levels and altered lipid metabolism due to peripheral insulin resistance and defects of insulin secretion in the pancreatic β-cells. While some cases of obesity and Type II diabetes result from genetic dysfunction, the increased worldwide incidence of these two disorders strongly suggest that the contribution of environmental factors such as sedentary lifestyles and high-calorie intake may disrupt energy balance. AMP-activated protein kinase and its upstream kinase liver kinase B1 are conserved serine/threonine kinases regulating anabolic and catabolic metabolic processes, therefore representing attractive therapeutic targets for the treatment of obesity and Type II diabetes. In this review, we will discuss the advantages of targeting the liver kinase B1/AMP-activated protein kinase pathway for the treatment of metabolic diseases.
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Abstract
AMP-activated protein kinase AMP-activated protein kinase (AMPK AMPK ), a phylogenetically conserved serine/threonine protein kinase, is a major regulator of cellular and whole-body energy homeostasis that coordinates metabolic pathways in order to balance nutrient supply with energy demand. It is now recognized that pharmacological activation of AMPK improves blood glucose homeostasis, lipid profile, and blood pressure in insulin-resistant rodents. Indeed, AMPK activation mimics the beneficial effects of physical activity or those of calorie restriction calorie restriction by acting on multiple cellular targets. In addition, it is now demonstrated that AMPK is one of the probable (albeit indirect) targets of major antidiabetic drugs drugs including the biguanides (metformin metformin ) and thiazolidinedione thiazolidinedione s, as well as of insulin-sensitizing adipokines (e.g., adiponectin adiponectin ). Taken together, such findings highlight the logic underlying the concept of targeting the AMPK pathway for the treatment of metabolic syndrome and type 2 diabetes.
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Weismann D, Erion DM, Ignatova-Todorava I, Nagai Y, Stark R, Hsiao JJ, Flannery C, Birkenfeld AL, May T, Kahn M, Zhang D, Yu XX, Murray SF, Bhanot S, Monia BP, Cline GW, Shulman GI, Samuel VT. Knockdown of the gene encoding Drosophila tribbles homologue 3 (Trib3) improves insulin sensitivity through peroxisome proliferator-activated receptor-γ (PPAR-γ) activation in a rat model of insulin resistance. Diabetologia 2011; 54:935-44. [PMID: 21190014 PMCID: PMC4061906 DOI: 10.1007/s00125-010-1984-5] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2010] [Accepted: 10/20/2010] [Indexed: 11/27/2022]
Abstract
AIMS/HYPOTHESIS Insulin action is purportedly modulated by Drosophila tribbles homologue 3 (TRIB3), which in vitro prevents thymoma viral proto-oncogene (AKT) and peroxisome proliferator-activated receptor-γ (PPAR-γ) activation. However, the physiological impact of TRIB3 action in vivo remains controversial. METHODS We investigated the role of TRIB3 in rats treated with either a control or Trib3 antisense oligonucleotide (ASO). Tissue-specific insulin sensitivity was assessed in vivo using a euglycaemic-hyperinsulinaemic clamp. A separate group was treated with the PPAR-γ antagonist bisphenol-A-diglycidyl ether (BADGE) to assess the role of PPAR-γ in mediating the response to Trib3 ASO. RESULTS Trib3 ASO treatment specifically reduced Trib3 expression by 70% to 80% in liver and white adipose tissue. Fasting plasma glucose, insulin concentrations and basal rate of endogenous glucose production were unchanged. However, Trib3 ASO increased insulin-stimulated whole-body glucose uptake by ~50% during the euglycaemic-hyperinsulinaemic clamp. This was attributable to improved skeletal muscle glucose uptake. Despite the reduction of Trib3 expression, AKT2 activity was not increased. Trib3 ASO increased white adipose tissue mass by 70% and expression of Ppar-γ and its key target genes, raising the possibility that Trib3 ASO improves insulin sensitivity primarily in a PPAR-γ-dependent manner. Co-treatment with BADGE blunted the expansion of white adipose tissue and abrogated the insulin-sensitising effects of Trib3 ASO. Finally, Trib3 ASO also increased plasma HDL-cholesterol, a change that persisted with BADGE co-treatment. CONCLUSIONS/INTERPRETATION These data suggest that TRIB3 inhibition improves insulin sensitivity in vivo primarily in a PPAR-γ-dependent manner and without any change in AKT2 activity.
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Affiliation(s)
- D. Weismann
- Section of Endocrinology, Department of Internal Medicine PO BOX 802010, Yale University School of Medicine, New Haven, CT 06520-8020, USA
- Universitätsklinikum Würzburg, Medizinische Klinik und Poliklinik I, Schwerpunkt Endokrinologie und Diabetologie, Würzburg, Germany
| | - D. M. Erion
- Section of Endocrinology, Department of Internal Medicine PO BOX 802010, Yale University School of Medicine, New Haven, CT 06520-8020, USA
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT, USA
- Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT, USA
| | - I. Ignatova-Todorava
- Section of Endocrinology, Department of Internal Medicine PO BOX 802010, Yale University School of Medicine, New Haven, CT 06520-8020, USA
| | - Y. Nagai
- Section of Endocrinology, Department of Internal Medicine PO BOX 802010, Yale University School of Medicine, New Haven, CT 06520-8020, USA
| | - R. Stark
- Section of Endocrinology, Department of Internal Medicine PO BOX 802010, Yale University School of Medicine, New Haven, CT 06520-8020, USA
| | - J. J. Hsiao
- Section of Endocrinology, Department of Internal Medicine PO BOX 802010, Yale University School of Medicine, New Haven, CT 06520-8020, USA
| | - C. Flannery
- Section of Endocrinology, Department of Internal Medicine PO BOX 802010, Yale University School of Medicine, New Haven, CT 06520-8020, USA
| | - A. L. Birkenfeld
- Section of Endocrinology, Department of Internal Medicine PO BOX 802010, Yale University School of Medicine, New Haven, CT 06520-8020, USA
| | - T. May
- Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT, USA
| | - M. Kahn
- Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT, USA
| | - D. Zhang
- Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT, USA
| | - X. X. Yu
- Isis Pharmaceuticals, Carlsbad, CA, USA
| | | | - S. Bhanot
- Isis Pharmaceuticals, Carlsbad, CA, USA
| | | | - G. W. Cline
- Section of Endocrinology, Department of Internal Medicine PO BOX 802010, Yale University School of Medicine, New Haven, CT 06520-8020, USA
| | - G. I. Shulman
- Section of Endocrinology, Department of Internal Medicine PO BOX 802010, Yale University School of Medicine, New Haven, CT 06520-8020, USA
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT, USA
- Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT, USA
| | - V. T. Samuel
- Section of Endocrinology, Department of Internal Medicine PO BOX 802010, Yale University School of Medicine, New Haven, CT 06520-8020, USA
- Veterans Affairs Medical Center, West Haven, CT, USA
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Laker RC, Henry BA, Wadley GD, Clarke IJ, Canny BJ, McConell GK. Central infusion of leptin does not increase AMPK signaling in skeletal muscle of sheep. Am J Physiol Regul Integr Comp Physiol 2010; 300:R511-8. [PMID: 21148475 DOI: 10.1152/ajpregu.00079.2010] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
In sheep, central leptin infusion reduces food intake and increases energy expenditure in adipose tissue and skeletal muscle. The mechanisms for these peripheral effects of central leptin in sheep are not known but, on the basis of rodent studies, may involve AMPK. In mice, central leptin acutely increases both skeletal muscle AMPK activation and glucose uptake. Thus, to investigate whether these effects exist in higher-order mammals, ovariectomized Corriedale ewes (n = 4 per group) received a continuous lateral ventricular infusion (60 μl/h) of either leptin (50 μg/h) or artificial cerebrospinal fluid (aCSF; CON) for 8 days. Tritiated glucose (3-(3)H-glucose) was infused intravenously for calculation of whole body glucose turnover during both acute (6 h) and chronic (7-8 days) leptin/aCSF infusion. Muscle biopsies were also obtained. Leptin infusion reduced (P < 0.05) food intake and body weight, and it also increased plasma epinephrine concentration at 6 h and 7 days, suggesting increased sympathetic nerve activity. Despite this, and in contrast to rodent studies, central leptin infusion did not increase skeletal muscle AMPKα Thr(172) phosphorylation or ACCβ Ser(221) phosphorylation. Surprisingly, the glucose rate of appearance (glucose Ra) and rate of disappearance (glucose Rd) were reduced by both acute and chronic leptin infusion. Direct infusion of the AMPK activator 5-aminoimidazole-4-carboxyamide-ribonucleoside (AICAR) into the femoral artery increased skeletal muscle AMPK phosphorylation. In conclusion, although central leptin infusion in sheep caused the predicted reduction in food intake and increases plasma epinephrine concentration, it had no effect on AMPK activation in skeletal muscle and actually reduced glucose disposal. This suggests that there are species differences in the peripheral responses to central leptin infusion.
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Affiliation(s)
- Rhianna C Laker
- Department of Physiology, University of Melbourne, Victoria, Australia
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Steinberg GR, O'Neill HM, Dzamko NL, Galic S, Naim T, Koopman R, Jørgensen SB, Honeyman J, Hewitt K, Chen ZP, Schertzer JD, Scott JW, Koentgen F, Lynch GS, Watt MJ, van Denderen BJW, Campbell DJ, Kemp BE. Whole body deletion of AMP-activated protein kinase {beta}2 reduces muscle AMPK activity and exercise capacity. J Biol Chem 2010; 285:37198-209. [PMID: 20855892 DOI: 10.1074/jbc.m110.102434] [Citation(s) in RCA: 133] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
AMP-activated protein kinase (AMPK) β subunits (β1 and β2) provide scaffolds for binding α and γ subunits and contain a carbohydrate-binding module important for regulating enzyme activity. We generated C57Bl/6 mice with germline deletion of AMPK β2 (β2 KO) and examined AMPK expression and activity, exercise capacity, metabolic control during muscle contractions, aminoimidazole carboxamide ribonucleotide (AICAR) sensitivity, and susceptibility to obesity-induced insulin resistance. We find that β2 KO mice are viable and breed normally. β2 KO mice had a reduction in skeletal muscle AMPK α1 and α2 expression despite up-regulation of the β1 isoform. Heart AMPK α2 expression was also reduced but this did not affect resting AMPK α1 or α2 activities. AMPK α1 and α2 activities were not changed in liver, fat, or hypothalamus. AICAR-stimulated glucose uptake but not fatty acid oxidation was impaired in β2 KO mice. During treadmill running β2 KO mice had reduced maximal and endurance exercise capacity, which was associated with lower muscle and heart AMPK activity and reduced levels of muscle and liver glycogen. Reductions in exercise capacity of β2 KO mice were not due to lower muscle mitochondrial content or defects in contraction-stimulated glucose uptake or fatty acid oxidation. When challenged with a high-fat diet β2 KO mice gained more weight and were more susceptible to the development of hyperinsulinemia and glucose intolerance. In summary these data show that deletion of AMPK β2 reduces AMPK activity in skeletal muscle resulting in impaired exercise capacity and the worsening of diet-induced obesity and glucose intolerance.
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Affiliation(s)
- Gregory R Steinberg
- Department of Medicine, McMaster University, Hamilton, Ontario L8N 3Z5, Canada
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Lactic acidosis triggers starvation response with paradoxical induction of TXNIP through MondoA. PLoS Genet 2010; 6:e1001093. [PMID: 20844768 PMCID: PMC2937306 DOI: 10.1371/journal.pgen.1001093] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2010] [Accepted: 07/27/2010] [Indexed: 12/31/2022] Open
Abstract
Although lactic acidosis is a prominent feature of solid tumors, we still have limited understanding of the mechanisms by which lactic acidosis influences metabolic phenotypes of cancer cells. We compared global transcriptional responses of breast cancer cells in response to three distinct tumor microenvironmental stresses: lactic acidosis, glucose deprivation, and hypoxia. We found that lactic acidosis and glucose deprivation trigger highly similar transcriptional responses, each inducing features of starvation response. In contrast to their comparable effects on gene expression, lactic acidosis and glucose deprivation have opposing effects on glucose uptake. This divergence of metabolic responses in the context of highly similar transcriptional responses allows the identification of a small subset of genes that are regulated in opposite directions by these two conditions. Among these selected genes, TXNIP and its paralogue ARRDC4 are both induced under lactic acidosis and repressed with glucose deprivation. This induction of TXNIP under lactic acidosis is caused by the activation of the glucose-sensing helix-loop-helix transcriptional complex MondoA:Mlx, which is usually triggered upon glucose exposure. Therefore, the upregulation of TXNIP significantly contributes to inhibition of tumor glycolytic phenotypes under lactic acidosis. Expression levels of TXNIP and ARRDC4 in human cancers are also highly correlated with predicted lactic acidosis pathway activities and associated with favorable clinical outcomes. Lactic acidosis triggers features of starvation response while activating the glucose-sensing MondoA-TXNIP pathways and contributing to the “anti-Warburg” metabolic effects and anti-tumor properties of cancer cells. These results stem from integrative analysis of transcriptome and metabolic response data under various tumor microenvironmental stresses and open new paths to explore how these stresses influence phenotypic and metabolic adaptations in human cancers. Solid tumors usually have many differences in their chemical environments, such as low oxygen, depletion of glucose, high acidity (low pH), and accumulation of lactate, from normal tissues. These changes are usually called tumor microenvironmental stresses. In this study, we have used microarrays to compare the transcriptional response and metabolic adaptation in response to these different stresses seen in the tumor microenvironments. Through these comparisons, we have found that lactic acidosis triggers a starvation response, highly similar to glucose deprivation, even in the presence of abundant nutrients and oxygen. Even the cells seem to be starved; cells under lactic acidosis have decreased glucose uptake. We found this unexpected biological behavior was due to the paradoxical induction of a glucose-sensing Mondo-TXNIP pathway. The activation of this novel anti-tumor pathway under lactic acidosis contributes to the anti-Warburg effect and the restriction of cell growth in tumorigenesis by limiting nutrient availability and its inactivation may be required for tumor progression under these microenvironmental stresses.
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Sucrose nonfermenting AMPK-related kinase (SNARK) mediates contraction-stimulated glucose transport in mouse skeletal muscle. Proc Natl Acad Sci U S A 2010; 107:15541-6. [PMID: 20713714 DOI: 10.1073/pnas.1008131107] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
The signaling mechanisms that mediate the important effects of contraction to increase glucose transport in skeletal muscle are not well understood, but are known to occur through an insulin-independent mechanism. Muscle-specific knockout of LKB1, an upstream kinase for AMPK and AMPK-related protein kinases, significantly inhibited contraction-stimulated glucose transport. This finding, in conjunction with previous studies of ablated AMPKalpha2 activity showing no effect on contraction-stimulated glucose transport, suggests that one or more AMPK-related protein kinases are important for this process. Muscle contraction increased sucrose nonfermenting AMPK-related kinase (SNARK) activity, an effect blunted in the muscle-specific LKB1 knockout mice. Expression of a mutant SNARK in mouse tibialis anterior muscle impaired contraction-stimulated, but not insulin-stimulated, glucose transport. Whole-body SNARK heterozygotic knockout mice also had impaired contraction-stimulated glucose transport in skeletal muscle, and knockdown of SNARK in C2C12 muscle cells impaired sorbitol-stimulated glucose transport. SNARK is activated by muscle contraction and is a unique mediator of contraction-stimulated glucose transport in skeletal muscle.
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Kennedy KM, Dewhirst MW. Tumor metabolism of lactate: the influence and therapeutic potential for MCT and CD147 regulation. Future Oncol 2010; 6:127-48. [PMID: 20021214 DOI: 10.2217/fon.09.145] [Citation(s) in RCA: 207] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Tumor metabolism consists of complex interactions between oxygenation states, metabolites, ions, the vascular network and signaling cascades. Accumulation of lactate within tumors has been correlated with poor clinical outcomes. While its production has negative implications, potentially contributing to tumor progression, the implications of the ability of tumors to utilize lactate can offer new therapeutic targets for the future. Monocarboxylate transporters (MCTs) of the SLC16A gene family influence substrate availability, the metabolic path of lactate and pH balance within the tumor. CD147, a chaperone to some MCT subtypes, contributes to tumor progression and metastasis. The implications and consequences of lactate utilization by tumors are currently unknown; therefore future research is needed on the intricacies of tumor metabolism. The possibility of metabolic modification of the tumor microenvironment via regulation or manipulation of MCT1 and CD147 may prove to be promising avenues of therapeutic options.
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Affiliation(s)
- Kelly M Kennedy
- Pathology department, Research Drive, Duke University Medical Center, NC 27710, USA
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Fazakerley DJ, Holman GD, Marley A, James DE, Stöckli J, Coster ACF. Kinetic evidence for unique regulation of GLUT4 trafficking by insulin and AMP-activated protein kinase activators in L6 myotubes. J Biol Chem 2009; 285:1653-60. [PMID: 19915010 PMCID: PMC2804323 DOI: 10.1074/jbc.m109.051185] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
In L6 myotubes, redistribution of a hemagglutinin (HA) epitope-tagged GLUT4 (HA-GLUT4) to the cell surface occurs rapidly in response to insulin stimulation and AMP-activated protein kinase (AMPK) activation. We have examined whether these separate signaling pathways have a convergent mechanism that leads to GLUT4 mobilization and to changes in GLUT4 recycling. HA antibody uptake on GLUT4 in the basal steady state reached a final equilibrium level that was only 81% of the insulin-stimulated level. AMPK activators (5-aminoimidazole-4-carboxyamide ribonucleoside (AICAR) and A-769662) led to a similar level of antibody uptake to that found in insulin-stimulated cells. However, the combined responses to insulin stimulation and AMPK activation led to an antibody uptake level of ∼20% above the insulin level. Increases in antibody uptake due to insulin, but not AICAR or A-769662, treatment were reduced by both wortmannin and Akt inhibitor. The GLUT4 internalization rate constant in the basal steady state was very rapid (0.43 min−1) and was decreased during the steady-state responses to insulin (0.18 min−1), AICAR (0.16 min−1), and A-769662 (0.24 min−1). This study has revealed a nonconvergent mobilization of GLUT4 in response to activation of Akt and AMPK signaling. Furthermore, GLUT4 trafficking in L6 muscle cells is very reliant on regulated endocytosis for control of cell surface GLUT4 levels.
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Affiliation(s)
- Daniel J Fazakerley
- Department of Biology and Biochemistry, University of Bath, Claverton Down, Bath BA27AY, United Kingdom
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