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Langer HT, Rohm M, Goncalves MD, Sylow L. AMPK as a mediator of tissue preservation: time for a shift in dogma? Nat Rev Endocrinol 2024:10.1038/s41574-024-00992-y. [PMID: 38760482 DOI: 10.1038/s41574-024-00992-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 04/19/2024] [Indexed: 05/19/2024]
Abstract
Ground-breaking discoveries have established 5'-AMP-activated protein kinase (AMPK) as a central sensor of metabolic stress in cells and tissues. AMPK is activated through cellular starvation, exercise and drugs by either directly or indirectly affecting the intracellular AMP (or ADP) to ATP ratio. In turn, AMPK regulates multiple processes of cell metabolism, such as the maintenance of cellular ATP levels, via the regulation of fatty acid oxidation, glucose uptake, glycolysis, autophagy, mitochondrial biogenesis and degradation, and insulin sensitivity. Moreover, AMPK inhibits anabolic processes, such as lipogenesis and protein synthesis. These findings support the notion that AMPK is a crucial regulator of cell catabolism. However, studies have revealed that AMPK's role in cell homeostasis might not be as unidirectional as originally thought. This Review explores emerging evidence for AMPK as a promoter of cell survival and an enhancer of anabolic capacity in skeletal muscle and adipose tissue during catabolic crises. We discuss AMPK-activating interventions for tissue preservation during tissue wasting in cancer-associated cachexia and explore the clinical potential of AMPK activation in wasting conditions. Overall, we provide arguments that call for a shift in the current dogma of AMPK as a mere regulator of cell catabolism, concluding that AMPK has an unexpected role in tissue preservation.
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Affiliation(s)
- Henning Tim Langer
- Division of Endocrinology, Weill Department of Medicine, Weill Cornell Medicine, New York, NY, USA.
- Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riβ, Germany.
| | - Maria Rohm
- Institute for Diabetes and Cancer, Helmholtz Center Munich, Neuherberg, Germany
- Joint Heidelberg-IDC Translational Diabetes Program, Inner Medicine 1, Heidelberg University Hospital, Heidelberg, Germany
- German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Marcus DaSilva Goncalves
- Division of Endocrinology, Weill Department of Medicine, Weill Cornell Medicine, New York, NY, USA
| | - Lykke Sylow
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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2
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Bosso M, Haddad D, Al Madhoun A, Al-Mulla F. Targeting the Metabolic Paradigms in Cancer and Diabetes. Biomedicines 2024; 12:211. [PMID: 38255314 PMCID: PMC10813379 DOI: 10.3390/biomedicines12010211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 01/09/2024] [Accepted: 01/11/2024] [Indexed: 01/24/2024] Open
Abstract
Dysregulated metabolic dynamics are evident in both cancer and diabetes, with metabolic alterations representing a facet of the myriad changes observed in these conditions. This review delves into the commonalities in metabolism between cancer and type 2 diabetes (T2D), focusing specifically on the contrasting roles of oxidative phosphorylation (OXPHOS) and glycolysis as primary energy-generating pathways within cells. Building on earlier research, we explore how a shift towards one pathway over the other serves as a foundational aspect in the development of cancer and T2D. Unlike previous reviews, we posit that this shift may occur in seemingly opposing yet complementary directions, akin to the Yin and Yang concept. These metabolic fluctuations reveal an intricate network of underlying defective signaling pathways, orchestrating the pathogenesis and progression of each disease. The Warburg phenomenon, characterized by the prevalence of aerobic glycolysis over minimal to no OXPHOS, emerges as the predominant metabolic phenotype in cancer. Conversely, in T2D, the prevailing metabolic paradigm has traditionally been perceived in terms of discrete irregularities rather than an OXPHOS-to-glycolysis shift. Throughout T2D pathogenesis, OXPHOS remains consistently heightened due to chronic hyperglycemia or hyperinsulinemia. In advanced insulin resistance and T2D, the metabolic landscape becomes more complex, featuring differential tissue-specific alterations that affect OXPHOS. Recent findings suggest that addressing the metabolic imbalance in both cancer and diabetes could offer an effective treatment strategy. Numerous pharmaceutical and nutritional modalities exhibiting therapeutic effects in both conditions ultimately modulate the OXPHOS-glycolysis axis. Noteworthy nutritional adjuncts, such as alpha-lipoic acid, flavonoids, and glutamine, demonstrate the ability to reprogram metabolism, exerting anti-tumor and anti-diabetic effects. Similarly, pharmacological agents like metformin exhibit therapeutic efficacy in both T2D and cancer. This review discusses the molecular mechanisms underlying these metabolic shifts and explores promising therapeutic strategies aimed at reversing the metabolic imbalance in both disease scenarios.
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Affiliation(s)
- Mira Bosso
- Department of Pathology, Faculty of Medicine, Health Science Center, Kuwait University, Safat 13110, Kuwait
| | - Dania Haddad
- Department of Genetics and Bioinformatics, Dasman Diabetes Institute, Dasman 15462, Kuwait; (D.H.); (A.A.M.)
| | - Ashraf Al Madhoun
- Department of Genetics and Bioinformatics, Dasman Diabetes Institute, Dasman 15462, Kuwait; (D.H.); (A.A.M.)
- Department of Animal and Imaging Core Facilities, Dasman Diabetes Institute, Dasman 15462, Kuwait
| | - Fahd Al-Mulla
- Department of Pathology, Faculty of Medicine, Health Science Center, Kuwait University, Safat 13110, Kuwait
- Department of Genetics and Bioinformatics, Dasman Diabetes Institute, Dasman 15462, Kuwait; (D.H.); (A.A.M.)
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Zarini S, Zemski Berry KA, Kahn DE, Garfield A, Perreault L, Kerege A, Bergman BC. Deoxysphingolipids: Atypical Skeletal Muscle Lipids Related to Insulin Resistance in Humans That Decrease Insulin Sensitivity In Vitro. Diabetes 2023; 72:884-897. [PMID: 37186949 PMCID: PMC10281238 DOI: 10.2337/db22-1018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Accepted: 04/19/2023] [Indexed: 05/17/2023]
Abstract
Sphingolipids are thought to promote skeletal muscle insulin resistance. Deoxysphingolipids (dSLs) are atypical sphingolipids that are increased in the plasma of individuals with type 2 diabetes and cause β-cell dysfunction in vitro. However, their role in human skeletal muscle is unknown. We found that dSL species are significantly elevated in muscle of individuals with obesity and type 2 diabetes compared with athletes and lean individuals and are inversely related to insulin sensitivity. Furthermore, we observed a significant reduction in muscle dSL content in individuals with obesity who completed a combined weight loss and exercise intervention. Increased dSL content in primary human myotubes caused a decrease in insulin sensitivity associated with increased inflammation, decreased AMPK phosphorylation, and altered insulin signaling. Our findings reveal a central role for dSL in human muscle insulin resistance and suggest dSLs as therapeutic targets for the treatment and prevention of type 2 diabetes. ARTICLE HIGHLIGHTS Deoxysphingolipids (dSLs) are atypical sphingolipids elevated in the plasma of individuals with type 2 diabetes, and their role in muscle insulin resistance has not been investigated. We evaluated dSL in vivo in skeletal muscle from cross-sectional and longitudinal insulin-sensitizing intervention studies and in vitro in myotubes manipulated to synthesize higher dSLs. dSLs were increased in the muscle of people with insulin resistance, inversely correlated to insulin sensitivity, and significantly decreased after an insulin-sensitizing intervention; increased intracellular dSL concentrations cause myotubes to become more insulin resistant. Reduction of muscle dSL levels is a potential novel therapeutic target to prevent/treat skeletal muscle insulin resistance.
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Affiliation(s)
- Simona Zarini
- Division of Endocrinology, Metabolism, and Diabetes, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO
| | - Karin A. Zemski Berry
- Division of Endocrinology, Metabolism, and Diabetes, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO
| | - Darcy E. Kahn
- Division of Endocrinology, Metabolism, and Diabetes, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO
| | - Amanda Garfield
- Division of Endocrinology, Metabolism, and Diabetes, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO
| | - Leigh Perreault
- Division of Endocrinology, Metabolism, and Diabetes, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO
| | - Anna Kerege
- Division of Endocrinology, Metabolism, and Diabetes, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO
| | - Bryan C. Bergman
- Division of Endocrinology, Metabolism, and Diabetes, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO
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Reduced Tyrosine and Serine-632 Phosphorylation of Insulin Receptor Substrate-1 in the Gastrocnemius Muscle of Obese Zucker Rat. Curr Issues Mol Biol 2022; 44:6015-6027. [PMID: 36547071 PMCID: PMC9777198 DOI: 10.3390/cimb44120410] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 11/20/2022] [Accepted: 11/21/2022] [Indexed: 12/03/2022] Open
Abstract
Obesity has become a serious health problem in the world, with increased morbidity, mortality, and financial burden on patients and health-care providers. The skeletal muscle is the most extensive tissue, severely affected by a sedentary lifestyle, which leads to obesity and type 2 diabetes. Obesity disrupts insulin signaling in the skeletal muscle, resulting in decreased glucose disposal, a condition known as insulin resistance. Although there is a large body of evidence on obesity-induced insulin resistance in various skeletal muscles, the molecular mechanism of insulin resistance due to a disruption in insulin receptor signaling, specifically in the gastrocnemius skeletal muscle of obese Zucker rats (OZRs), is not fully understood. This study subjected OZRs to a glucose tolerance test (GTT) to analyze insulin sensitivity. In addition, immunoprecipitation and immunoblotting techniques were used to determine the expression and tyrosine phosphorylation of insulin receptor substrate-1 (IRS-1) and insulin receptor-β (IRβ), and the activation of serine-632-IRS-1 phosphorylation in the gastrocnemius muscle of Zucker rats. The results show that the GTT in the OZRs was impaired. There was a significant decrease in IRS-1 levels, but no change was observed in IRβ in the gastrocnemius muscle of OZRs, compared to Zucker leans. Obese rats had a higher ratio of tyrosine phosphorylation of IRS-1 and IRβ than lean rats. In obese rats, however, insulin was unable to induce tyrosine phosphorylation. Moreover, insulin increased the phosphorylation of serine 632-IRS-1 in the gastrocnemius muscle of lean rats. However, obese rats had a low basal level of serine-632-IRS-1 and insulin only mildly increased serine phosphorylation in obese rats, compared to those without insulin. Thus, we addressed the altered steps of the insulin receptor signal transduction in the gastrocnemius muscle of OZRs. These findings may contribute to a better understanding of human obesity and type 2 diabetes.
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Yoshida S, Hatasa M, Ohsugi Y, Tsuchiya Y, Liu A, Niimi H, Morita K, Shimohira T, Sasaki N, Maekawa S, Shiba T, Hirota T, Okano T, Hirose A, Ibi R, Noritake K, Tomiga Y, Nitta H, Suzuki T, Takahashi H, Miyasaka N, Iwata T, Katagiri S. Porphyromonas gingivalis Administration Induces Gestational Obesity, Alters Gene Expression in the Liver and Brown Adipose Tissue in Pregnant Mice, and Causes Underweight in Fetuses. Front Cell Infect Microbiol 2022; 11:745117. [PMID: 35096633 PMCID: PMC8792863 DOI: 10.3389/fcimb.2021.745117] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Accepted: 12/07/2021] [Indexed: 12/18/2022] Open
Abstract
Preventing adverse pregnancy outcomes is crucial for maternal and child health. Periodontal disease is a risk factor for many systemic diseases including adverse pregnancy outcomes, such as preterm birth and low birth weight. In addition, the administration of the periodontopathic bacterium Porphyromonas gingivalis exacerbates obesity, glucose tolerance, and hepatic steatosis and alters endocrine function in the brown adipose tissue (BAT). However, the effects of having periodontal disease during pregnancy remain unclear. Thus, this study investigates the effect of P. gingivalis administration on obesity, liver, and BAT during pregnancy. Sonicated P. gingivalis (Pg) or saline (Co) was injected intravenously and administered orally to pregnant C57BL/6J mice three times per week. Maternal body weight and fetal body weight on embryonic day (ED) 18 were evaluated. Microarray analysis and qPCR in the liver and BAT and hepatic and plasma triglyceride quantification were performed on dams at ED 18. The body weight of Pg dams was heavier than that of Co dams; however, the fetal body weight was decreased in the offspring of Pg dams. Microarray analysis revealed 254 and 53 differentially expressed genes in the liver and BAT, respectively. Gene set enrichment analysis exhibited the downregulation of fatty acid metabolism gene set in the liver and estrogen response early/late gene sets in the BAT, whereas inflammatory response and IL6/JAK/STAT3 signaling gene sets were upregulated both in the liver and BAT. The downregulation of expression levels of Lpin1, Lpin2, and Lxra in the liver, which are associated with triglyceride synthesis, and a decreasing trend in hepatic triglyceride of Pg dams were observed. P. gingivalis administration may alter lipid metabolism in the liver. Overall, the intravenous and oral administration of sonicated P. gingivalis-induced obesity and modified gene expression in the liver and BAT in pregnant mice and caused fetuses to be underweight.
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Affiliation(s)
- Sumiko Yoshida
- Department of Periodontology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - Masahiro Hatasa
- Department of Periodontology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - Yujin Ohsugi
- Department of Periodontology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - Yosuke Tsuchiya
- Department of Periodontology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - Anhao Liu
- Department of Periodontology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - Hiromi Niimi
- Department of Periodontology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - Kazuki Morita
- Department of Periodontology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - Tsuyoshi Shimohira
- Department of Periodontology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - Naoki Sasaki
- Oral Diagnosis and General Dentistry, Division of Clinical Dentistry, Tokyo Medical and Dental University Hospital, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - Shogo Maekawa
- Department of Periodontology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - Takahiko Shiba
- Department of Periodontology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - Tomomitsu Hirota
- Division of Molecular Genetics, Research Center for Medical Sciences, The Jikei University School of Medicine, Tokyo, Japan
| | - Tokuju Okano
- Department of Bacterial Pathogenesis, Infection and Host Response, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - Asuka Hirose
- Comprehensive Reproductive Medicine, Regulation of Internal Environment and Reproduction, Systemic Organ Regulation, Graduate School, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - Rinko Ibi
- Comprehensive Reproductive Medicine, Regulation of Internal Environment and Reproduction, Systemic Organ Regulation, Graduate School, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - Kanako Noritake
- Oral Diagnosis and General Dentistry, Division of Clinical Dentistry, Tokyo Medical and Dental University Hospital, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - Yuki Tomiga
- Division of Metabolism and Endocrinology, Faculty of Medicine, Saga University, Saga, Japan
| | - Hiroshi Nitta
- Oral Diagnosis and General Dentistry, Division of Clinical Dentistry, Tokyo Medical and Dental University Hospital, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - Toshihiko Suzuki
- Department of Bacterial Pathogenesis, Infection and Host Response, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - Hirokazu Takahashi
- Division of Metabolism and Endocrinology, Faculty of Medicine, Saga University, Saga, Japan
- Liver Center, Saga University Hospital, Faculty of Medicine, Saga University, Saga, Japan
| | - Naoyuki Miyasaka
- Comprehensive Reproductive Medicine, Regulation of Internal Environment and Reproduction, Systemic Organ Regulation, Graduate School, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - Takanori Iwata
- Department of Periodontology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - Sayaka Katagiri
- Department of Periodontology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
- *Correspondence: Sayaka Katagiri,
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6
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Yang Z, Yu GL, Zhu X, Peng TH, Lv YC. Critical roles of FTO-mediated mRNA m6A demethylation in regulating adipogenesis and lipid metabolism: Implications in lipid metabolic disorders. Genes Dis 2022; 9:51-61. [PMID: 35005107 PMCID: PMC8720706 DOI: 10.1016/j.gendis.2021.01.005] [Citation(s) in RCA: 46] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Revised: 12/19/2020] [Accepted: 01/20/2021] [Indexed: 02/06/2023] Open
Abstract
The goal this review is to clarify the effects of the fat mass and obesity-associated protein (FTO) in lipid metabolism regulation and related underlying mechanisms through the FTO-mediated demethylation of m6A modification. FTO catalyzes the demethylation of m6A to alter the processing, maturation and translation of the mRNAs of lipid-related genes. FTO overexpression in the liver promotes lipogenesis and lipid droplet (LD) enlargement and suppresses CPT-1–mediated fatty acid oxidation via the SREBP1c pathway, promoting excessive lipid storage and nonalcoholic fatty liver diseases (NAFLD). FTO enhances preadipocyte differentiation through the C/EBPβ pathway, and facilitates adipogenesis and fat deposition by altering the alternative splicing of RUNX1T1, the expression of PPARγ and ANGPTL4, and the phosphorylation of PLIN1, whereas it inhibits lipolysis by inhibiting IRX3 expression and the leptin pathway, causing the occurrence and development of obesity. Suppression of the PPARβ/δ and AMPK pathways by FTO-mediated m6A demethylation damages lipid utilization in skeletal muscles, leading to the occurrence of diabetic hyperlipidemia. m6A demethylation by FTO inhibits macrophage lipid influx by downregulating PPARγ protein expression and accelerates cholesterol efflux by phosphorylating AMPK, thereby impeding foam cell formation and atherosclerosis development. In summary, FTO-mediated m6A demethylation modulates the expression of lipid-related genes to regulate lipid metabolism and lipid disorder diseases.
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Affiliation(s)
- Zhou Yang
- Clinical Anatomy & Reproductive Medicine Application Institute, Hengyang Medical College, University of South China, Hengyang, Hunan 421001, PR China
| | - Guang-Li Yu
- Clinical Anatomy & Reproductive Medicine Application Institute, Hengyang Medical College, University of South China, Hengyang, Hunan 421001, PR China
| | - Xiao Zhu
- Guangxi Key Laboratory of Diabetic Systems Medicine, Guilin Medical University, Guilin, Guangxi 541199, PR China
| | - Tian-Hong Peng
- Clinical Anatomy & Reproductive Medicine Application Institute, Hengyang Medical College, University of South China, Hengyang, Hunan 421001, PR China
| | - Yun-Cheng Lv
- Clinical Anatomy & Reproductive Medicine Application Institute, Hengyang Medical College, University of South China, Hengyang, Hunan 421001, PR China.,Guangxi Key Laboratory of Diabetic Systems Medicine, Guilin Medical University, Guilin, Guangxi 541199, PR China
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7
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Pyun DH, Kim TJ, Park SY, Lee HJ, Abd El-Aty AM, Jeong JH, Jung TW. Patchouli alcohol ameliorates skeletal muscle insulin resistance and NAFLD via AMPK/SIRT1-mediated suppression of inflammation. Mol Cell Endocrinol 2021; 538:111464. [PMID: 34601002 DOI: 10.1016/j.mce.2021.111464] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 09/22/2021] [Accepted: 09/26/2021] [Indexed: 02/06/2023]
Abstract
Obesity-induced chronic low-grade inflammation and thus causes various metabolic diseases, such as insulin resistance and non-alcoholic fatty liver disease (NAFLD). Patchouli alcohol (PA), an active component extracted from patchouli, displayed anti-inflammatory effects on different cell types. However, the impact of PA on skeletal muscle insulin signaling and hepatic lipid metabolism remains unclear. This study aimed to investigate whether PA would affect insulin signaling impairment in myocytes and lipid metabolism in hepatocytes. Treatment with PA ameliorated palmitate-induced inflammation and aggravation of insulin signaling in C2C12 myocytes and lipid accumulation in HepG2 hepatocytes. Treatment of C2C12 myocytes and HepG2 cells with PA augmented AMP-activated protein kinase (AMPK) phosphorylation and Sirtuin 1 (SIRT1) expression in a dose-dependent manner. siRNA-mediated suppression of AMPK or SIRT1 mitigated the effects of PA on palmitate-induced inflammation and insulin resistance in C2C12 myocytes and lipid accumulation in HepG2 cells. Animal experiments demonstrated that PA administration increased AMPK phosphorylation and SIRT1 expression, and ameliorated inflammation, thereby attenuating skeletal muscle insulin resistance and hepatic steatosis in high-fat diet-fed mice. These results denote that PA alleviates skeletal muscle insulin resistance and hepatic steatosis through AMPK/SIRT1-dependent signaling. This study might provide a novel therapeutic approach for treating obesity-related insulin resistance and NAFLD.
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Affiliation(s)
- Do Hyeon Pyun
- Department of Pharmacology, College of Medicine, Chung-Ang University, Seoul, Republic of Korea
| | - Tae Jin Kim
- Department of Pharmacology, College of Medicine, Chung-Ang University, Seoul, Republic of Korea
| | - Seung Yeon Park
- Department of Pharmacology, College of Medicine, Chung-Ang University, Seoul, Republic of Korea; Department of Global Innovative Drugs, Graduate School of Chung-Ang University, Seoul, Republic of Korea
| | - Hyun Jung Lee
- Department of Global Innovative Drugs, Graduate School of Chung-Ang University, Seoul, Republic of Korea; Department of Anatomy and Cell Biology, College of Medicine, Chung-Ang University, Seoul, South Korea
| | - A M Abd El-Aty
- State Key Laboratory of Biobased Material and Green Papermaking, Qilu University of Technology, Shandong Academy of Sciences, Jinan, Shandong 250353, China; Department of Medical Pharmacology, Medical Faculty, Ataturk University, Erzurum, Turkey; Department of Pharmacology, Faculty of Veterinary Medicine, Cairo University, Giza 12211, Egypt.
| | - Ji Hoon Jeong
- Department of Pharmacology, College of Medicine, Chung-Ang University, Seoul, Republic of Korea; Department of Global Innovative Drugs, Graduate School of Chung-Ang University, Seoul, Republic of Korea
| | - Tae Woo Jung
- Department of Pharmacology, College of Medicine, Chung-Ang University, Seoul, Republic of Korea.
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8
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Das AS, Alfonzo JD, Accornero F. The importance of RNA modifications: From cells to muscle physiology. WILEY INTERDISCIPLINARY REVIEWS-RNA 2021; 13:e1700. [PMID: 34664402 DOI: 10.1002/wrna.1700] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2021] [Revised: 08/30/2021] [Accepted: 09/27/2021] [Indexed: 12/25/2022]
Abstract
Naturally occurring post-transcriptional chemical modifications serve critical roles in impacting RNA structure and function. More directly, modifications may affect RNA stability, intracellular transport, translational efficiency, and fidelity. The combination of effects caused by modifications are ultimately linked to gene expression regulation at a genome-wide scale. The latter is especially true in systems that undergo rapid metabolic and or translational remodeling in response to external stimuli, such as the presence of stressors, but beyond that, modifications may also affect cell homeostasis. Although examples of the importance of RNA modifications in translation are accumulating rapidly, still what these contribute to the function of complex physiological systems such as muscle is only recently emerging. In the present review, we will introduce key information on various modifications and highlight connections between those and cellular malfunctions. In passing, we will describe well-documented roles for modifications in the nervous system and use this information as a stepping stone to emphasize a glaring paucity of knowledge on the role of RNA modifications in heart and skeletal muscle, with particular emphasis on mitochondrial function in those systems. This article is categorized under: RNA in Disease and Development > RNA in Disease RNA Processing > RNA Editing and Modification.
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Affiliation(s)
- Anindhya Sundar Das
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, Ohio, USA.,The Center for RNA Biology, The Ohio State University, Columbus, Ohio, USA
| | - Juan D Alfonzo
- The Center for RNA Biology, The Ohio State University, Columbus, Ohio, USA.,Department of Microbiology, The Ohio State University, Columbus, Ohio, USA
| | - Federica Accornero
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, Ohio, USA.,The Center for RNA Biology, The Ohio State University, Columbus, Ohio, USA
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9
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Jeddi S, Gheibi S, Kashfi K, Ghasemi A. Sodium hydrosulfide has no additive effects on nitrite-inhibited renal gluconeogenesis in type 2 diabetic rats. Life Sci 2021; 283:119870. [PMID: 34352258 DOI: 10.1016/j.lfs.2021.119870] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 07/20/2021] [Accepted: 07/25/2021] [Indexed: 11/19/2022]
Abstract
OBJECTIVE Increased renal and hepatic gluconeogenesis are important sources of fasting hyperglycemia in type 2 diabetes (T2D). The inhibitory effect of co-administration of sodium nitrite and sodium hydrosulfide (NaSH) on hepatic but not renal gluconeogenesis has been reported in rats with T2D. The present study aimed to determine the effects of co-administration of sodium nitrite and NaSH on the expression of genes involved in renal gluconeogenesis in rats with T2D. METHODS T2D was induced by a combination of a high-fat diet and low-dose streptozotocin (30 mg/kg). Male Wistar rats were divided into 5 groups (n = 6/group): Control, T2D, T2D + nitrite, T2D + NaSH, and T2D + nitrite+NaSH. Nitrite and NaSH were administered for nine weeks at a dose of 50 mg/L (in drinking water) and 0.28 mg/kg (daily intraperitoneal injection), respectively. Serum levels of urea and creatinine, and mRNA expressions of PEPCK, G6Pase, FBPase, PC, PI3K, AKT, PGC-1α, and FoxO1 in the renal tissue, were measured at the end of the study. RESULTS Nitrite decreased mRNA expression of PEPCK by 39%, G6Pase by 43%, FBPase by 41%, PC by 63%, PGC-1α by 45%, and FoxO1 by 27% in the renal tissue of rats with T2D; co-administration of nitrite and NaSH further decreases FoxO1, while had no additive effects on the tissue expression of the other genes. In addition, nitrite+NaSH decreased elevated serum urea levels by 58% and creatinine by 37% in rats with T2D. CONCLUSION The inhibitory effect of nitrite on gluconeogenesis in T2D rats is at least in part due to decreased mRNA expressions of renal gluconeogenic genes. Unlike effects on hepatic gluconeogenesis, co-administration of nitrite and NaSH has no additive effects on genes involved in renal gluconeogenesis in rats with T2D.
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Affiliation(s)
- Sajad Jeddi
- Endocrine Physiology Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Sevda Gheibi
- Endocrine Physiology Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran; Department of Clinical Sciences in Malmö, Unit of Molecular Metabolism, Lund University Diabetes Centre, Clinical Research Center, Lund University, Malmö, Sweden
| | - Khosrow Kashfi
- Department of Molecular, Cellular, Biomedical Sciences, Sophie Davis School of Biomedical Education, City University of New York School of Medicine, New York, USA; Graduate Program in Biology, City University of New York Graduate Center, New York, USA
| | - Asghar Ghasemi
- Endocrine Physiology Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
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10
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Han Y, Lu Z, Chen S, Zhong C, Yan M, Wang H, Meng M, Liu M. Abdominal Massage Alleviates Skeletal Muscle Insulin Resistance by Regulating the AMPK/SIRT1/PGC-1α Signaling Pathway. Cell Biochem Biophys 2021; 79:895-903. [PMID: 33966249 PMCID: PMC8558202 DOI: 10.1007/s12013-021-00983-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Accepted: 03/31/2021] [Indexed: 12/12/2022]
Abstract
Abdominal massage (AM), a traditional Chinese medicine-based treatment method, has received considerable attention in the recent years. The aim of the present study was to investigate the effect of AM on high-fat diet (HFD)-induced insulin resistance (IR) in comparison with resveratrol (RSV) treatment. Forty-eight male Sprague-Dawley rats were randomly divided into the following four groups: standard chow diet (control group), high-fat diet (model group), HFD + abdominal massage (AM group), and HFD + resveratrol (RSV group). A rat model of IR was established by feeding HFD to rats for 8 weeks followed by treatment with AM or RSV for 4 weeks. The underlying HFD-induced IR molecular mechanisms were studied in rat serum and skeletal muscles. RSV and AM significantly improved glucose intolerance, hyperglycemia, obesity, and significantly reduced lipid accumulation [triglyceride (TC), total cholesterol (TG), low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C)], adipocytokine [free fatty acids (FFA), adiponectin (ADPN)] and serum pro-inflammatory cytokines (IL-6 and TNF-α) secretion. In addition, AM activated the AMPK/SIRT1 signaling pathway in rat skeletal muscle. In conclusion, our results showed that AM could improve IR by regulating the secretion of adipocytokines, pro-inflammatory cytokines as well as related signaling pathways in the skeletal muscle of rats, which might provide insights into development of new treatment methods for the clinical treatment of IR.
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Affiliation(s)
- Yiran Han
- Departments of Acupuncture and Massage, Changchun University of Chinese Medicine, Changchun, 130117, Jilin Province, PR China
| | - Zeyuan Lu
- Department of Pharmacology, School of Pharmaceutical Sciences, Jilin University, Changchun, Jilin Province, 130021, PR China
| | - Shaotao Chen
- Departments of Acupuncture and Massage, Changchun University of Chinese Medicine, Changchun, 130117, Jilin Province, PR China
| | - Chongwen Zhong
- Departments of Acupuncture and Massage, Changchun University of Chinese Medicine, Changchun, 130117, Jilin Province, PR China
| | - Minghui Yan
- Departments of Acupuncture and Massage, Changchun University of Chinese Medicine, Changchun, 130117, Jilin Province, PR China
| | - Heran Wang
- Departments of Acupuncture and Massage, Changchun University of Chinese Medicine, Changchun, 130117, Jilin Province, PR China
| | - Meng Meng
- Departments of Acupuncture and Massage, Changchun University of Chinese Medicine, Changchun, 130117, Jilin Province, PR China
| | - Mingjun Liu
- Departments of Acupuncture and Massage, Changchun University of Chinese Medicine, Changchun, 130117, Jilin Province, PR China.
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11
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Jiang P, Ren L, Zhi L, Yu Z, Lv F, Xu F, Peng W, Bai X, Cheng K, Quan L, Zhang X, Wang X, Zhang Y, Yang D, Hu X, Xiao RP. Negative regulation of AMPK signaling by high glucose via E3 ubiquitin ligase MG53. Mol Cell 2021; 81:629-637.e5. [PMID: 33400924 DOI: 10.1016/j.molcel.2020.12.008] [Citation(s) in RCA: 57] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 11/30/2020] [Accepted: 12/03/2020] [Indexed: 02/06/2023]
Abstract
As a master regulator of metabolism, AMP-activated protein kinase (AMPK) is activated upon energy and glucose shortage but suppressed upon overnutrition. Exaggerated negative regulation of AMPK signaling by nutrient overload plays a crucial role in metabolic diseases. However, the mechanism underlying the negative regulation is poorly understood. Here, we demonstrate that high glucose represses AMPK signaling via MG53 (also called TRIM72) E3-ubiquitin-ligase-mediated AMPKα degradation and deactivation. Specifically, high-glucose-stimulated reactive oxygen species (ROS) signals AKT to phosphorylate AMPKα at S485/491, which facilitates the recruitment of MG53 and the subsequent ubiquitination and degradation of AMPKα. In addition, high glucose deactivates AMPK by ROS-dependent suppression of phosphorylation of AMPKα at T172. These findings not only delineate the mechanism underlying the impairment of AMPK signaling in overnutrition-related diseases but also highlight the significance of keeping the yin-yang balance of AMPK signaling in the maintenance of metabolic homeostasis.
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Affiliation(s)
- Peng Jiang
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing 100871, China
| | - Lejiao Ren
- Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China; Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
| | - Li Zhi
- Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China; Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
| | - Zhong Yu
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing 100871, China
| | - Fengxiang Lv
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing 100871, China
| | - Fengli Xu
- Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China; Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
| | - Wei Peng
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing 100871, China
| | - Xiaoyu Bai
- Morningside Laboratory for Chemical Biology, Department of Chemistry, The University of Hong Kong, Hong Kong, China
| | - Kunlun Cheng
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing 100871, China
| | - Li Quan
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing 100871, China
| | - Xiuqin Zhang
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing 100871, China
| | - Xianhua Wang
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing 100871, China
| | - Yan Zhang
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing 100871, China
| | - Dan Yang
- Morningside Laboratory for Chemical Biology, Department of Chemistry, The University of Hong Kong, Hong Kong, China
| | - Xinli Hu
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing 100871, China.
| | - Rui-Ping Xiao
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing 100871, China; Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China; Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China; Beijing City Key Laboratory of Cardiometabolic Molecular Medicine, Peking University, Beijing 100871, China; PKU-Nanjing Institute of Translational Medicine, Nanjing 211800, China.
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12
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Jeddi S, Gheibi S, Carlström M, Kashfi K, Ghasemi A. Long-term co-administration of sodium nitrite and sodium hydrosulfide inhibits hepatic gluconeogenesis in male type 2 diabetic rats: Role of PI3K-Akt-eNOS pathway. Life Sci 2020; 265:118770. [PMID: 33212150 DOI: 10.1016/j.lfs.2020.118770] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Revised: 11/05/2020] [Accepted: 11/13/2020] [Indexed: 12/18/2022]
Abstract
OBJECTIVE A deficiency in hydrogen sulfide (H2S) and nitric oxide (NO) contributes to the development of type 2 diabetes (T2D). An inhibitory effect on liver gluconeogenesis has been reported in rats with T2D with co-administration of sodium nitrite and sodium hydrosulfide (NaSH); the underlying mechanisms have however not yet been elucidated. The aim of this study is to determine the long-term effects of co-administering sodium nitrite and NaSH on expression of genes involved in liver gluconeogenesis in rats with T2D. METHODS T2D was induced using a high fat diet combined with low-dose of streptozotocin (30 mg/kg). Rats were divided into 5 groups (n = 7/group): Control, T2D, T2D + nitrite, T2D + NaSH, and T2D + nitrite+NaSH. Nitrite (50 mg/L) and NaSH (0.28 mg/kg) were administered for 9 weeks. Intraperitoneal pyruvate tolerance test (PTT) was performed at the end of the ninth week and mRNA expressions of PI3K, Akt, eNOS, PEPCK, G6Pase, and FBPase were measured in the liver. RESULTS Co-administration of nitrite and NaSH decreased elevated serum glucose concentrations during PTT. Compared to T2D + nitrite, co-administration of nitrite and NaSH resulted in significant increases in mRNA expression of PI3K, Akt, and eNOS and significant decreases in mRNA expression of G6Pase and FBPase but had no effect on PEPCK expression. CONCLUSION Long-term NaSH administration at low-dose, potentiated the inhibitory effects of nitrite on mRNA expression of key liver gluconeogenic enzymes in rats with T2D. This inhibitory effect of nitrite and NaSH co-administration on gluconeogenesis were associated with increased gene expression of PI3K, Akt, and eNOS in the liver.
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Affiliation(s)
- Sajad Jeddi
- Endocrine Physiology Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Sevda Gheibi
- Endocrine Physiology Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran; Department of Clinical Sciences in Malmö, Unit of Molecular Metabolism, Lund University Diabetes Centre, Clinical Research Center, Malmö University Hospital, Lund University, Malmö, Sweden
| | - Mattias Carlström
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Khosrow Kashfi
- Department of Molecular, Cellular and Biomedical Sciences, Sophie Davis School of Biomedical Education, City University of New York School of Medicine, New York, USA.
| | - Asghar Ghasemi
- Endocrine Physiology Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
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13
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Danaher J, Stathis CG, Wilson RA, Moreno-Asso A, Wellard RM, Cooke MB. High intensity exercise downregulates FTO mRNA expression during the early stages of recovery in young males and females. Nutr Metab (Lond) 2020; 17:68. [PMID: 32821265 PMCID: PMC7433063 DOI: 10.1186/s12986-020-00489-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Accepted: 08/04/2020] [Indexed: 12/26/2022] Open
Abstract
Background Physical exercise and activity status may modify the effect of the fat mass- and obesity-associated (FTO) genotype on body weight and obesity risk. To understand the interaction between FTO's effect and physical activity, the present study investigated the effects of high and low intensity exercise on FTO mRNA and protein expression, and potential modifiers of exercise-induced changes in FTO in healthy-weighted individuals. Methods Twenty-eight untrained males and females (25.4 ± 1.1 years; 73.1 ± 2.0 kg; 178.8 ± 1.4 cm; 39.0 ± 1.2 ml.kg.min- 1 VO2peak) were genotyped for the FTO rs9939609 (T > A) polymorphism and performed isocaloric (400 kcal) cycle ergometer exercise on two separate occasions at different intensities: 80% (High Intensity (HI)) and 40% (Low Intensity (LO)) VO2peak. Skeletal muscle biopsies (vastus lateralis) and blood samples were taken pre-exercise and following 10 and 90 mins passive recovery. Results FTO mRNA expression was significantly decreased after HI intensity exercise (p = 0.003). No differences in basal and post-exercise FTO protein expression were evident between FTO genotypes. Phosphorylated adenosine monophosphate-activated protein kinase (AMPK) and Akt substrate of 160 kDa (AS160) were significantly increased following HI intensity exercise (p < 0.05). Multivariate models of metabolomic data (orthogonal two partial least squares discriminant analysis (O2PLS-DA)) were unable to detect any significant metabolic differences between genotypes with either exercise trial (p > 0.05). However, skeletal muscle glucose accumulation at 10 mins following HI (p = 0.021) and LO (p = 0.033) intensity exercise was greater in AA genotypes compared to TT genotypes. Conclusion Our novel data provides preliminary evidence regarding the effects of exercise on FTO expression in skeletal muscle. Specifically, high intensity exercise downregulates expression of FTO mRNA and suggests that in addition to nutritional regulation, FTO could also be regulated by exercise. Trial registration ACTRN12612001230842. Registered 21 November 2012 - Prospectively registered, https://www.anzctr.org.au/.
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Affiliation(s)
- Jessica Danaher
- School of Science, College of Science, Engineering and Health, RMIT University, Melbourne, Australia
| | - Christos G Stathis
- Institute for Health and Sport, Victoria University, Melbourne, Australia
| | - Robin A Wilson
- School of Medicine, NYU Langone Health, New York, USA.,Australian Institute for Musculoskeletal Science (AIMSS), Department of Medicine-Western Health, Melbourne Medical School, The University of Melbourne, Melbourne, Australia
| | - Alba Moreno-Asso
- Institute for Health and Sport, Victoria University, Melbourne, Australia.,Australian Institute for Musculoskeletal Science (AIMSS), Department of Medicine-Western Health, Melbourne Medical School, The University of Melbourne, Melbourne, Australia
| | - R Mark Wellard
- Science and Engineering Faculty, Queensland University of Technology, Brisbane, Australia
| | - Matthew B Cooke
- Australian Institute for Musculoskeletal Science (AIMSS), Department of Medicine-Western Health, Melbourne Medical School, The University of Melbourne, Melbourne, Australia.,Department of Health and Medical Sciences, Faculty of Health, Arts and Design, Swinburne University of Technology, Melbourne, VIC 3122 Australia
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14
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Guo J, Pereira TJ, Mori Y, Gonzalez Medina M, Breen DM, Dalvi PS, Zhang H, McCole DF, McBurney MW, Heximer SP, Tsiani EL, Dolinsky VW, Giacca A. Resveratrol Inhibits Neointimal Growth after Arterial Injury in High-Fat-Fed Rodents: The Roles of SIRT1 and AMPK. J Vasc Res 2020; 57:325-340. [PMID: 32777783 DOI: 10.1159/000509217] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Accepted: 05/20/2020] [Indexed: 12/12/2022] Open
Abstract
We have shown that both insulin and resveratrol (RSV) decrease neointimal hyperplasia in chow-fed rodents via mechanisms that are in part overlapping and involve the activation of endothelial nitric oxide synthase (eNOS). However, this vasculoprotective effect of insulin is abolished in high-fat-fed insulin-resistant rats. Since RSV, in addition to increasing insulin sensitivity, can activate eNOS via pathways that are independent of insulin signaling, such as the activation of sirtuin 1 (SIRT1) and AMP-activated kinase (AMPK), we speculated that unlike insulin, the vasculoprotective effect of RSV would be retained in high-fat-fed rats. We found that high-fat feeding decreased insulin sensitivity and increased neointimal area and that RSV improved insulin sensitivity (p < 0.05) and decreased neointimal area in high-fat-fed rats (p < 0.05). We investigated the role of SIRT1 in the effect of RSV using two genetic mouse models. We found that RSV decreased neointimal area in high-fat-fed wild-type mice (p < 0.05), an effect that was retained in mice with catalytically inactive SIRT1 (p < 0.05) and in heterozygous SIRT1-null mice. In contrast, the effect of RSV was abolished in AMKPα2-null mice. Thus, RSV decreased neointimal hyperplasia after arterial injury in both high-fat-fed rats and mice, an effect likely not mediated by SIRT1 but by AMPKα2.
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Affiliation(s)
- June Guo
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Troy J Pereira
- Department of Pharmacology and Therapeutics, Children's Hospital Research Institute of Manitoba, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Yusaku Mori
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada.,Division of Diabetes, Metabolism and Endocrinology, Showa University School of Medicine, Tokyo, Japan
| | | | - Danna M Breen
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Prasad S Dalvi
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada.,Biology Department, Morosky College of Health Professions and Sciences, Gannon University, Erie, Pennsylvania, USA
| | - Hangjun Zhang
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Declan F McCole
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, California, USA
| | - Michael W McBurney
- Program in Cancer Therapeutics, Ottawa Hospital Research Institute, Departments of Medicine and Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario, Canada
| | - Scott P Heximer
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Evangelia L Tsiani
- Department of Health Sciences, Brock University, St. Catharines, Ontario, Canada.,Centre for Bone and Muscle Health, Brock University, St. Catharines, Ontario, Canada
| | - Vernon W Dolinsky
- Department of Pharmacology and Therapeutics, Children's Hospital Research Institute of Manitoba, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Adria Giacca
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada, .,Department of Medicine, University of Toronto, Toronto, Ontario, Canada, .,Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada, .,Banting and Best Diabetes Centre, University of Toronto, Toronto General Hospital, Toronto, Ontario, Canada,
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15
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Lantier L, Williams AS, Williams IM, Guerin A, Bracy DP, Goelzer M, Foretz M, Viollet B, Hughey CC, Wasserman DH. Reciprocity Between Skeletal Muscle AMPK Deletion and Insulin Action in Diet-Induced Obese Mice. Diabetes 2020; 69:1636-1649. [PMID: 32439824 PMCID: PMC7372072 DOI: 10.2337/db19-1074] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Accepted: 05/19/2020] [Indexed: 11/13/2022]
Abstract
Insulin resistance due to overnutrition places a burden on energy-producing pathways in skeletal muscle (SkM). Nevertheless, energy state is not compromised. The hypothesis that the energy sensor AMPK is necessary to offset the metabolic burden of overnutrition was tested using chow-fed and high-fat (HF)-fed SkM-specific AMPKα1α2 knockout (mdKO) mice and AMPKα1α2lox/lox littermates (wild-type [WT]). Lean mdKO and WT mice were phenotypically similar. HF-fed mice were equally obese and maintained lean mass regardless of genotype. Results did not support the hypothesis that AMPK is protective during overnutrition. Paradoxically, mdKO mice were more insulin sensitive. Insulin-stimulated SkM glucose uptake was approximately twofold greater in mdKO mice in vivo. Furthermore, insulin signaling, SkM GLUT4 translocation, hexokinase activity, and glycolysis were increased. AMPK and insulin signaling intersect at mammalian target of rapamycin (mTOR), a critical node for cell proliferation and survival. Basal mTOR activation was reduced by 50% in HF-fed mdKO mice, but was normalized by insulin stimulation. Mitochondrial function was impaired in mdKO mice, but energy charge was preserved by AMP deamination. Results show a surprising reciprocity between SkM AMPK signaling and insulin action that manifests with diet-induced obesity, as insulin action is preserved to protect fundamental energetic processes in the muscle.
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Affiliation(s)
- Louise Lantier
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN
- Vanderbilt Mouse Metabolic Phenotyping Center, Nashville, TN
| | - Ashley S Williams
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN
| | - Ian M Williams
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN
| | - Amanda Guerin
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN
| | - Deanna P Bracy
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN
| | - Mickael Goelzer
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN
| | - Marc Foretz
- Université de Paris, Institut Cochin, CNRS, INSERM, Paris, France
| | - Benoit Viollet
- Université de Paris, Institut Cochin, CNRS, INSERM, Paris, France
| | - Curtis C Hughey
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN
| | - David H Wasserman
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN
- Vanderbilt Mouse Metabolic Phenotyping Center, Nashville, TN
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16
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Genetic loss of AMPK-glycogen binding destabilises AMPK and disrupts metabolism. Mol Metab 2020; 41:101048. [PMID: 32610071 PMCID: PMC7393401 DOI: 10.1016/j.molmet.2020.101048] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Revised: 06/09/2020] [Accepted: 06/25/2020] [Indexed: 12/19/2022] Open
Abstract
OBJECTIVE Glycogen is a major energy reserve in liver and skeletal muscle. The master metabolic regulator AMP-activated protein kinase (AMPK) associates with glycogen via its regulatory β subunit carbohydrate-binding module (CBM). However, the physiological role of AMPK-glycogen binding in energy homeostasis has not been investigated in vivo. This study aimed to determine the physiological consequences of disrupting AMPK-glycogen interactions. METHODS Glycogen binding was disrupted in mice via whole-body knock-in (KI) mutation of either the AMPK β1 (W100A) or β2 (W98A) isoform CBM. Systematic whole-body, tissue and molecular phenotyping was performed in KI and respective wild-type (WT) mice. RESULTS While β1 W100A KI did not affect whole-body metabolism or exercise capacity, β2 W98A KI mice displayed increased adiposity and impairments in whole-body glucose handling and maximal exercise capacity relative to WT. These KI mutations resulted in reduced total AMPK protein and kinase activity in liver and skeletal muscle of β1 W100A and β2 W98A, respectively, versus WT mice. β1 W100A mice also displayed loss of fasting-induced liver AMPK total and α-specific kinase activation relative to WT. Destabilisation of AMPK was associated with increased fat deposition in β1 W100A liver and β2 W98A skeletal muscle versus WT. CONCLUSIONS These results demonstrate that glycogen binding plays critical roles in stabilising AMPK and maintaining cellular, tissue and whole-body energy homeostasis.
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17
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Insulin Resistance in Osteoarthritis: Similar Mechanisms to Type 2 Diabetes Mellitus. J Nutr Metab 2020; 2020:4143802. [PMID: 32566279 PMCID: PMC7261331 DOI: 10.1155/2020/4143802] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 05/01/2020] [Accepted: 05/11/2020] [Indexed: 02/06/2023] Open
Abstract
Osteoarthritis (OA) and type 2 diabetes mellitus (T2D) are two of the most widespread chronic diseases. OA and T2D have common epidemiologic traits, are considered heterogenic multifactorial pathologies that develop through the interaction of genetic and environmental factors, and have common risk factors. In addition, both of these diseases often manifest in a single patient. Despite differences in clinical manifestations, both diseases are characterized by disturbances in cellular metabolism and by an insulin-resistant state primarily associated with the production and utilization of energy. However, currently, the primary cause of OA development and progression is not clear. In addition, although OA is manifested as a joint disease, evidence has accumulated that it affects the whole body. As pathological insulin resistance is viewed as a driving force of T2D development, now, we present evidence that the molecular and cellular metabolic disturbances associated with OA are linked to an insulin-resistant state similar to T2D. Moreover, the alterations in cellular energy requirements associated with insulin resistance could affect many metabolic changes in the body that eventually result in pathology and could serve as a unified mechanism that also functions in many metabolic diseases. However, these issues have not been comprehensively described. Therefore, here, we discuss the basic molecular mechanisms underlying the pathological processes associated with the development of insulin resistance; the major inducers, regulators, and metabolic consequences of insulin resistance; and instruments for controlling insulin resistance as a new approach to therapy.
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18
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Chang W, Fa H, Xiao D, Wang J. MicroRNA-184 alleviates insulin resistance in cardiac myocytes and high fat diet-induced cardiac dysfunction in mice through the LPP3/DAG pathway. Mol Cell Endocrinol 2020; 508:110793. [PMID: 32229289 DOI: 10.1016/j.mce.2020.110793] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 03/14/2020] [Accepted: 03/15/2020] [Indexed: 01/05/2023]
Abstract
AIM Cardiovascular complication is a major cause of mortality and morbidity in patients with diabetes. Insulin sensitivity loss is a major contributor to the pathogenesis of cardiovascular diseases in diabetes. Based on our previous research, diacylglycerol (DAG) levels play an important role in high saturated fatty acid-induced insulin resistance. Phosphatidic acid phosphatase (LPP3), a key enzyme for synthesizing DAG, is indispensable for normal cardiac functions and vascular health. However, adipose knockdown of LPP3 increases insulin sensitivity, suggesting that LPP3 regulation may be complicated in hearts. The aim of this study was to investigate LPP3 roles in diabetic cardiac insulin sensitivity and to identify potential upstream targets implicated in diabetic cardiomyopathy. METHODS AND RESULTS Mice were fed a high fat diet (HF) or a low fat diet (control) for up to 24 weeks. After 24 weeks, we found that high fat diet-induced cardiac dysfunction is linked to elevated LPP3 compared to the control group (P < 0.05). In addition, knockdown of LPP3 rescued the glucose uptake that was impaired by palmitate treatment alone in cardiomyoblasts (P < 0.05). Furthermore, we identified miR-184 as an upstream regulator targeting LPP3 and further confirmed the link between DAG and insulin sensitivity. MiR-184 mimic transfection rescued the glucose uptake and glucose consumption that had been impaired by palmitate treatment alone (P < 0.05). CONCLUSION In hearts of high fat diet-fed mice, increased LPP3 contributes to insulin resistance via increased DAG levels. A small non-coding RNA, miR-184, at least partially regulates this signal pathway to alleviate insulin resistance.
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Affiliation(s)
- Wenguang Chang
- Center for Regenerative Medicine, Institute for Translational Medicine, Qingdao University, Qingdao, 266021, China.
| | - Hongge Fa
- Center for Regenerative Medicine, Institute for Translational Medicine, Qingdao University, Qingdao, 266021, China; School of Basic Medical Sciences, Qingdao University, Qingdao, China
| | - Dandan Xiao
- Center for Regenerative Medicine, Institute for Translational Medicine, Qingdao University, Qingdao, 266021, China; School of Basic Medical Sciences, Qingdao University, Qingdao, China
| | - Jianxun Wang
- School of Basic Medical Sciences, Qingdao University, Qingdao, China
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19
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Kim JH, Lee JO, Moon JW, Kang MJ, Byun WS, Han JA, Kim SJ, Park SH, Kim HS. Laminarin From Salicornia herbacea Stimulates Glucose Uptake Through AMPK-p38 MAPK Pathways in L6 Muscle Cells. Nat Prod Commun 2020. [DOI: 10.1177/1934578x20901409] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Laminarin is a component of brown seaweed, especially isolated from Salicornia herbacea. Laminarin was known to have various physiological functions, however, the molecular mechanism is still unclear. In this study, we report that laminarin stimulates an activation of AMP-activated protein kinase (AMPK) and increases glucose uptake in rat L6 myotubes. Laminarin also increases an intracellular calcium release. Inhibition of Ca2+ release, using with CaMKK inhibitor, STO-609, blocked laminarin-induced AMPK activity, indicating that laminarin stimulated AMPK activity via calcium. In addition, laminarin activates p38 mitogen-activated protein kinase (MAPK) signaling pathways depending on AMPK activity. Moreover, the inhibition of either AMPK or p38 MAPK blocked laminarin-induced glucose uptake in rat L6 myotubes. Taken together, these results demonstrate that the hypoglycemic effect of laminarin is caused by its ability to activate AMPK-p38 MAPK pathways in skeletal muscles.
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Affiliation(s)
- Ji H. Kim
- Department of Anatomy, Korea University College of Medicine, Seoul, Republic of Korea
| | - Jung O. Lee
- Department of Anatomy, Korea University College of Medicine, Seoul, Republic of Korea
| | - Ji W. Moon
- Department of Anatomy, Korea University College of Medicine, Seoul, Republic of Korea
| | - Min J. Kang
- Department of Anatomy, Korea University College of Medicine, Seoul, Republic of Korea
| | - Won S. Byun
- Department of Anatomy, Korea University College of Medicine, Seoul, Republic of Korea
| | - Jeong A. Han
- Department of Anatomy, Korea University College of Medicine, Seoul, Republic of Korea
| | - Su J. Kim
- Department of Anatomy, Korea University College of Medicine, Seoul, Republic of Korea
| | - Sun H. Park
- Department of Anatomy, Korea University College of Medicine, Seoul, Republic of Korea
| | - Hyeon S. Kim
- Department of Anatomy, Korea University College of Medicine, Seoul, Republic of Korea
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20
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Li X, Wang YX, Shi P, Liu YP, Li T, Liu SQ, Wang CJ, Wang LX, Cao Y. Icariin treatment reduces blood glucose levels in type 2 diabetic rats and protects pancreatic function. Exp Ther Med 2020; 19:2690-2696. [PMID: 32256750 PMCID: PMC7086278 DOI: 10.3892/etm.2020.8490] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Accepted: 01/13/2020] [Indexed: 12/22/2022] Open
Abstract
Icariin, a flavonoid isolated from traditional oriental herbal medicines, has been demonstrated to exhibit several health benefits in animal models and in humans. The aim of the present study was to investigate the effect of Icariin on hyperglycemia in type 2 diabetes mellitus (T2DM) in rats. A model of diabetes was established in 50 Sprague Dawley rats using a high-sugar and high-fat diet and peritoneal injection of streptozotocin. Diabetic rats were divided into five groups: Diabetic control; metformin; and rats treated with three different doses of Icariin, 5, 10 and 20 mg/kg. Body weight and blood glucose levels were measured, and serum adiponectin levels, expression of phospho-AMP mediated protein kinase (p-AMPK) and glucose transporter isoform 4 (GLUT-4) were measured using ELISA, Realtime PCR and western blotting, respectively. Diabetic rats without drug treatment exhibited reduced body weight, increased blood glucose levels and decreased the number of islets. In T2DM rats treated with 10 or 20 mg/kg Icariin, the blood glucose levels were reduced, whereas serum adiponectin levels were not affected. Additionally, the mRNA and protein expression levels of p-AMPK and GLUT-4 protein were increased in the T2DM rats treated with Icariin. In conclusion, in the diabetes rat model, Icariin alleviated the severity of diabetes, and the effects may be associated with reduction of hyperglycemia by activating an AMPK/GLUT-4 pathway.
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Affiliation(s)
- Xin Li
- Office of Drug Clinical Trial Management, The Affiliated Hospital of Qingdao University, Qingdao, Shandong 266003, P.R. China
| | - Yun-Xiao Wang
- Office of Drug Clinical Trial Management, The Affiliated Hospital of Qingdao University, Qingdao, Shandong 266003, P.R. China
| | - Ping Shi
- Office of Drug Clinical Trial Management, The Affiliated Hospital of Qingdao University, Qingdao, Shandong 266003, P.R. China
| | - Yan-Ping Liu
- Office of Drug Clinical Trial Management, The Affiliated Hospital of Qingdao University, Qingdao, Shandong 266003, P.R. China
| | - Ting Li
- Office of Drug Clinical Trial Management, The Affiliated Hospital of Qingdao University, Qingdao, Shandong 266003, P.R. China
| | - Shu-Qin Liu
- Office of Drug Clinical Trial Management, The Affiliated Hospital of Qingdao University, Qingdao, Shandong 266003, P.R. China
| | - Chen-Jing Wang
- Office of Drug Clinical Trial Management, The Affiliated Hospital of Qingdao University, Qingdao, Shandong 266003, P.R. China
| | - Le-Xin Wang
- Department of Cardiology, Liaocheng People's Hospital, Liaocheng, Shandong 252000, P.R. China.,School of Biomedical Sciences, Charles Sturt University, Wagga Wagga, New South Wales 2650, Australia
| | - Yu Cao
- Office of Drug Clinical Trial Management, The Affiliated Hospital of Qingdao University, Qingdao, Shandong 266003, P.R. China
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21
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Sun ZG, Tian G, Zheng XC, Liu WY, Luo XT, Xiao J, Song H, Xu X. AMPKα2 Deficiency Does Not Affect the Exercise-Induced Improvements in Glucose Tolerance and Metabolic Disorders in Mice Fed a High-Fat Diet. J Nutr Sci Vitaminol (Tokyo) 2020; 65:491-497. [PMID: 31902862 DOI: 10.3177/jnsv.65.491] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Exercise can improve obesity and metabolic disorders in mice fed a high-fat diet (HFD), but the role of AMPKα2 in the process remains unclear. The aim of this study was to investigate the role of AMPKα2 in the exercise-induced improvements in glucose tolerance and metabolic turnover in obesity mice. Male wild-type mice (n=12) and AMPKα2 knockout (AMPKα2 KO) mice (n=12) were fed a HFD for 16 wk and were then randomly divided into four groups: WT HFD group (WT HF), AMPKα2 KO HFD group (AMPKα2 KO HF), WT HFD exercise group (WT HE), and AMPK HFD exercise group (AMPKα2 KO HE). The HF groups continue to be fed a HFD from 16 wk to 24 wk, and the HE groups were fed a HFD and performed exercise training. After 8 wk of exercise, all mice were placed in an energy metabolism chamber to test their metabolic turnover, include locomotor activity, food intake, oxygen consumption (VO2), carbon dioxide production (VCO2), energy expenditure (EE) and respiratory exchange ratio (RER), over a period of 3 d. Exercise improved glucose tolerance, VO2, VCO2 and EE in mice fed a HFD (p<0.05). The VO2, VCO2 and EE in AMPKα2 KO HE group were lower than these in WT HE group (p<0.05). Our findings revealed exercise improved glucose tolerance and metabolic disorders in C57 and AMPKα2 KO mice fed a HFD. AMPKα2 is not essential for exercise-induced improvements in glucose tolerance and metabolic disorders.
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Affiliation(s)
- Zhong-Guang Sun
- Department of Exercise Rehabilitation, Shanghai University of Sport
| | - Ge Tian
- Beijing Xian Nong Tan Sports Technical College
| | - Xiao-Ci Zheng
- Department of Exercise Rehabilitation, Shanghai University of Sport
| | - Wen-Ying Liu
- Department of Exercise Rehabilitation, Shanghai University of Sport
| | - Xue-Ting Luo
- Department of Exercise Rehabilitation, Shanghai University of Sport
| | - Jing Xiao
- Department of Exercise Rehabilitation, Shanghai University of Sport
| | - Hui Song
- Department of Exercise Rehabilitation, Shanghai University of Sport
| | - Xin Xu
- Department of Exercise Rehabilitation, Shanghai University of Sport
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22
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Chetina EV, Markova GA, Sharapova EP. [there any association of metabolic disturbances with joint destruction and pain?]. BIOMEDIT︠S︡INSKAI︠A︡ KHIMII︠A︡ 2020; 65:441-456. [PMID: 31876515 DOI: 10.18097/pbmc20196506441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Osteoarthritis and type 2 diabetes mellitus represent two the most common chronic diseases. They possess many shared epidemiologic traits, have common risk factors, and embody heterogeneous multifactorial pathologies, which develop due to interaction of genetic an environmental factors. In addition, these diseases are often occurring in the same patient. In spite of the differences in clinical manifestation both diseases have similar disturbances of cellular metabolism, primarily associated with ATP production and utilization. The review discusses molecular mechanisms determining pathophysiological processes associated with glucose and lipid metabolism as well as the means aiming to alleviate the disturbances of energy metabolism as a new a therapeutic approach.
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Affiliation(s)
- E V Chetina
- Nasonova Research Institute of Rheumatology, Moscow, Russia
| | - G A Markova
- Nasonova Research Institute of Rheumatology, Moscow, Russia
| | - E P Sharapova
- Nasonova Research Institute of Rheumatology, Moscow, Russia
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23
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Wang Y, Li Y, Qiao J, Li N, Qiao S. AMPK α1 mediates the protective effect of adiponectin against insulin resistance in INS-1 pancreatic β cells. Cell Biochem Funct 2019; 37:625-632. [PMID: 31693217 DOI: 10.1002/cbf.3440] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Revised: 08/19/2019] [Accepted: 09/02/2019] [Indexed: 12/17/2022]
Abstract
The fat-derived protein adiponectin is known to reverse the effects of insulin resistance and to lower blood glucose levels. The AMP-activated protein kinase (AMPK) signalling pathway plays a central role in metabolism and energy homeostasis. Here, to investigate the role of AMPK in the protective effect of adiponectin against insulin resistance, we established the model of high-glucose (HG)- and high-lipid (HL)-induced insulin resistance in INS-1 pancreatic β cells. We found that 25mM of glucose and 0.4mM of palmitic acid treatment significantly increased cell apoptosis and impaired insulin secretion in INS-1 cells. However, recombinant human adiponectin dramatically reduced HG- and/or HL-induced cell apoptosis and greatly improved insulin secretion. Interestingly, adiponectin treatment also activated AMPK signalling pathway by increasing the phosphorylation of Thr172 in the AMPK α subunit; 10μM of compound C, a potent AMPK inhibitor, blocked the protective effects of adiponectin against HG/HL-induced insulin resistance. Furthermore, knockout experiments by CRISPR/Cas9 technology showed that AMPK α1, but not AMPK α2, is involved in the protective effects of adiponectin. Taken together, adiponectin reversed the effects of insulin resistance via AMPK α1, which provides a novel insight into the protective mechanism of adiponectin and may be used as a new strategy for the treatment of type 2 diabetes. SIGNIFICANCE OF THE STUDY: Adiponectin can reverse the effects of insulin resistance and lower blood glucose levels. Here, adiponectin reduced HG/HL-induced cell apoptosis and greatly improved insulin secretion. These effects were blocked by AMPK inhibitor, compound C. Specifically, we found that AMPK α1, but not AMPK α2, mediates the protective effects of adiponectin, which provides a novel insight into the protective mechanism of adiponectin against insulin resistance.
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Affiliation(s)
- Yan Wang
- Department of Endocrinology, The First Hospital of Shanxi Medical University, Taiyuan, Shanxi, China
| | - Yan Li
- Shanxi Medical University, Taiyuan, Shanxi, China
| | - Jing Qiao
- Shanxi Medical University, Taiyuan, Shanxi, China
| | - Na Li
- Shanxi Medical University, Taiyuan, Shanxi, China
| | - Shun Qiao
- Shanxi Medical University, Taiyuan, Shanxi, China
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24
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Zhang Z, Liu H, Liu J. Akt activation: A potential strategy to ameliorate insulin resistance. Diabetes Res Clin Pract 2019; 156:107092. [PMID: 29111280 DOI: 10.1016/j.diabres.2017.10.004] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Revised: 09/24/2017] [Accepted: 10/02/2017] [Indexed: 02/08/2023]
Abstract
Insulin resistance is a hallmark of type 2 diabetes and obesity while the mechanism remains unclear. Current therapy to treat type 2 diabetes is metformin, the 5'-monophosphate-activated protein kinase (AMPK) activator, owing to the ability to augment peripheral glucose uptake. However, metformin also displays limitations, as AMPK activation remains intact and regular in most type 2 diabetes and metformin does not seem to facilitate peripheral insulin resistance. Evidence has shown that PI3K-Akt/PKB pathway could be induced via insulin and act as an important effector. Akt/PKB is capable of inducing a great number of downstream molecules, such as translocating glucose transporters GLUTs to the cell membrane thus increase glucose uptake. Hence, any defect in Akt/PKB pathway along with the downstream molecules could lead to insulin resistance. Inositol pyrophosphates, synthesized by inositol hexakisphosphate (IP6) kinase 1 (IP6K1) and competitive with 3,4,5-bisphosphate (PIP3) to bind the PH domain of Akt/PKB, demonstrate the ability to inhibit Akt signaling. In addition, IP6K1 knockout mice present increased insulin sensitivity and obesity resistance, indicating a novel therapeutic target in confronting insulin resistance. Taken together, we conclude that Akt activation is another potential strategy to ameliorate insulin resistance.
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Affiliation(s)
- Zhengyi Zhang
- Center for Mitochondrial Biology and Medicine, The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology and Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an, China
| | - Huadong Liu
- Center for Mitochondrial Biology and Medicine, The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology and Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an, China
| | - Jiankang Liu
- Center for Mitochondrial Biology and Medicine, The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology and Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an, China.
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25
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Choi RH, McConahay A, Johnson MB, Jeong HW, Koh HJ. Adipose tissue-specific knockout of AMPKα1/α2 results in normal AICAR tolerance and glucose metabolism. Biochem Biophys Res Commun 2019; 519:633-638. [PMID: 31540695 DOI: 10.1016/j.bbrc.2019.09.049] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Accepted: 09/12/2019] [Indexed: 12/25/2022]
Abstract
AMP-activated protein kinase (AMPK) is a member of Ser/Thr kinases that has been shown to regulate energy balance. Although recent studies have demonstrated the function of AMPK in adipose tissue using different fat-specific AMPK knockout mouse models, the results were somewhat inconsistent. For this study, we tested the hypothesis that AMPK in adipose tissue regulates whole body glucose metabolism. To determine the role of adipose tissue AMPK in vivo, we generated fat-specific AMPKα1/α2 knockout mice (AMPKFKO) using the Cre-loxP system. Body weights of AMPKFKO mice were not different between 8 and 27 weeks of age. Furthermore, tissue weights (liver, kidney, muscle, heart and white and brown adipose tissue) were similar to wild type littermates and DEXA scan analysis revealed no differences in percentages of body fat and lean mass. Knockout of AMPKα1/α2 in adipose tissue abolished basal and AICAR-stimulated phosphorylation of AMPK and Acetyl-CoA Carboxylase, a downstream of AMPK. Despite of the ablation of AICAR-stimulated AMPK phosphorylation, the blood glucose-lowering effect of AICAR injection (i.p.) was normal in AMPKFKO mice. In addition, AMPKFKO displayed normal fasting blood glucose concentration, glucose tolerance, insulin tolerance, and insulin signaling, indicating normal whole body glucose metabolism. These data demonstrate that adipose tissue AMPK plays a minimum role in whole body glucose metabolism on a chow diet.
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Affiliation(s)
- Ran Hee Choi
- Division of Applied Physiology, Department of Exercise Science, University of South Carolina, Columbia, SC, 29208, USA
| | - Abigail McConahay
- Division of Applied Physiology, Department of Exercise Science, University of South Carolina, Columbia, SC, 29208, USA
| | - Mackenzie B Johnson
- Division of Applied Physiology, Department of Exercise Science, University of South Carolina, Columbia, SC, 29208, USA
| | - Ha-Won Jeong
- Division of Applied Physiology, Department of Exercise Science, University of South Carolina, Columbia, SC, 29208, USA
| | - Ho-Jin Koh
- Division of Applied Physiology, Department of Exercise Science, University of South Carolina, Columbia, SC, 29208, USA.
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26
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Koh JH, Hancock CR, Han DH, Holloszy JO, Nair KS, Dasari S. AMPK and PPARβ positive feedback loop regulates endurance exercise training-mediated GLUT4 expression in skeletal muscle. Am J Physiol Endocrinol Metab 2019; 316:E931-E939. [PMID: 30888859 PMCID: PMC6580175 DOI: 10.1152/ajpendo.00460.2018] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The objective of this study is to determine whether AMP-activated protein kinase (AMPK), peroxisome proliferator-activated receptor gamma coactivator 1-α (PGC-1α), or peroxisome proliferator-activated receptor β (PPARβ) can independently mediate the increase of glucose transporter type 4 (GLUT4) expression that occurs in response to exercise training. We found that PPARβ can regulate GLUT4 expression without PGC-1α. We also found AMPK and PPARβ are important for maintaining normal physiological levels of GLUT4 protein in the sedentary condition as well following exercise training. However, AMPK and PPARβ are not essential for the increase in GLUT4 protein expression that occurs in response to exercise training. We discovered that AMPK activation increases PPARβ via myocyte enhancer factor 2A (MEF2A), which acted as a transcription factor for PPARβ. Furthermore, exercise training increases the cooperation of AMPK and PPARβ to regulate glucose uptake. In conclusion, cooperation between AMPK and PPARβ via NRF-1/MEF2A pathway enhances the exercise training mediated adaptive increase in GLUT4 expression and subsequent glucose uptake in skeletal muscle.
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Affiliation(s)
- Jin-Ho Koh
- Department of Internal Medicine, Mayo Clinic , Rochester, Minnesota
- Department of Physiology, College of Medicine, Yeungnam University , Daegu , Korea
| | - Chad R Hancock
- Department of Nutrition, Dietetics and Food Science, Brigham Young University , Provo, Utah
| | - Dong-Ho Han
- Division of Geriatrics and Nutritional Sciences, Department of Medicine, Washington University School of Medicine , St. Louis, Missouri
| | - John O Holloszy
- Division of Geriatrics and Nutritional Sciences, Department of Medicine, Washington University School of Medicine , St. Louis, Missouri
| | | | - Surendra Dasari
- Department of Health Sciences Research, Mayo Clinic , Rochester, Minnesota
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27
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Geng T, Liu Y, Xu Y, Jiang Y, Zhang N, Wang Z, Carmichael GG, Taylor HS, Li D, Huang Y. H19 lncRNA Promotes Skeletal Muscle Insulin Sensitivity in Part by Targeting AMPK. Diabetes 2018; 67:2183-2198. [PMID: 30201684 PMCID: PMC6198334 DOI: 10.2337/db18-0370] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Accepted: 08/24/2018] [Indexed: 12/12/2022]
Abstract
Skeletal muscle plays a pivotal role in regulating systemic glucose homeostasis in part through the conserved cellular energy sensor AMPK. AMPK activation increases glucose uptake, lipid oxidation, and mitochondrial biogenesis, leading to enhanced muscle insulin sensitivity and whole-body energy metabolism. Here we show that the muscle-enriched H19 long noncoding RNA (lncRNA) acts to enhance muscle insulin sensitivity, at least in part, by activating AMPK. We identify the atypical dual-specificity phosphatase DUSP27/DUPD1 as a potentially important downstream effector of H19. We show that DUSP27, which is highly expressed in muscle with previously unknown physiological function, interacts with and activates AMPK in muscle cells. Consistent with decreased H19 expression in the muscle of insulin-resistant human subjects and rodents, mice with genetic H19 ablation exhibit muscle insulin resistance. Furthermore, a high-fat diet downregulates muscle H19 via both posttranscriptional and epigenetic mechanisms. Our results uncover an evolutionarily conserved, highly expressed lncRNA as an important regulator of muscle insulin sensitivity.
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Affiliation(s)
- Tingting Geng
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Yale School of Medicine, New Haven, CT
- Department of Endocrinology, First Affiliated Hospital of Xi'an Jiaotong University School of Medicine, Xi'an, Shaanxi, People's Republic of China
| | - Ya Liu
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Yale School of Medicine, New Haven, CT
- Department of Veterinary Medicine, College of Animal Science and Technology, Anhui Agricultural University, Hefei, Anhui, People's Republic of China
| | - Yetao Xu
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Yale School of Medicine, New Haven, CT
- Department of Obstetrics and Gynecology, First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, People's Republic of China
| | - Ying Jiang
- Department of Obstetrics, Women's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, People's Republic of China
| | - Na Zhang
- Department of Genetics and Genome Sciences, University of Connecticut Health Center, Farmington, CT
| | - Zhangsheng Wang
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Yale School of Medicine, New Haven, CT
- Department of Cardiology, Fifth People's Hospital of Shanghai, Fudan University, Shanghai, People's Republic of China
| | - Gordon G Carmichael
- Department of Genetics and Genome Sciences, University of Connecticut Health Center, Farmington, CT
| | - Hugh S Taylor
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Yale School of Medicine, New Haven, CT
| | - Da Li
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Yale School of Medicine, New Haven, CT
- Center of Reproductive Medicine, Department of Obstetrics and Gynecology, Shengjing Hospital, China Medical University, Shenyang, Liaoning, People's Republic of China
| | - Yingqun Huang
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Yale School of Medicine, New Haven, CT
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28
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Sasaki N, Katagiri S, Komazaki R, Watanabe K, Maekawa S, Shiba T, Udagawa S, Takeuchi Y, Ohtsu A, Kohda T, Tohara H, Miyasaka N, Hirota T, Tamari M, Izumi Y. Endotoxemia by Porphyromonas gingivalis Injection Aggravates Non-alcoholic Fatty Liver Disease, Disrupts Glucose/Lipid Metabolism, and Alters Gut Microbiota in Mice. Front Microbiol 2018; 9:2470. [PMID: 30405551 PMCID: PMC6207869 DOI: 10.3389/fmicb.2018.02470] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Accepted: 09/27/2018] [Indexed: 12/17/2022] Open
Abstract
Many risk factors related to the development of non-alcoholic fatty liver disease (NAFLD) have been proposed, including the most well-known of diabetes and obesity as well as periodontitis. As periodontal pathogenic bacteria produce endotoxins, periodontal treatment can result in endotoxemia. The aim of this study was to investigate the effects of intravenous, sonicated Porphyromonas gingivalis (Pg) injection on glucose/lipid metabolism, liver steatosis, and gut microbiota in mice. Endotoxemia was induced in C57BL/6J mice (8 weeks old) by intravenous injection of sonicated Pg; Pg was deactivated but its endotoxin remained. The mice were fed a high-fat diet and administered sonicated Pg (HFPg) or saline (HFco) injections for 12 weeks. Liver steatosis, glucose metabolism, and gene expression in the liver were evaluated. 16S rRNA gene sequencing with metagenome prediction was performed on the gut microbiota. Compared to HFco mice, HFPg mice exhibited impaired glucose tolerance and insulin resistance along with increased liver steatosis. Liver microarray analysis demonstrated that 1278 genes were differentially expressed between HFco and HFPg mice. Gene set enrichment analysis showed that fatty acid metabolism, hypoxia, and TNFα signaling via NFκB gene sets were enriched in HFPg mice. Although sonicated Pg did not directly reach the gut, it changed the gut microbiota and decreased bacterial diversity in HFPg mice. Metagenome prediction in the gut microbiota showed enriched citrate cycle and carbon fixation pathways in prokaryotes. Overall, intravenous injection of sonicated Pg caused impaired glucose tolerance, insulin resistance, and liver steatosis in mice fed high-fat diets. Thus, blood infusion of Pg contributes to NAFLD and alters the gut microbiota.
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Affiliation(s)
- Naoki Sasaki
- Department of Periodontology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Sayaka Katagiri
- Department of Periodontology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Rina Komazaki
- Department of Periodontology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Kazuki Watanabe
- Department of Periodontology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Shogo Maekawa
- Department of Periodontology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Takahiko Shiba
- Department of Periodontology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Sayuri Udagawa
- Department of Periodontology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Yasuo Takeuchi
- Department of Periodontology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Anri Ohtsu
- Department of Periodontology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Takashi Kohda
- Department of Epigenetics, Medical Research Institute, Tokyo Medical and Dental University, Tokyo, Japan.,Japan Agency for Medical Research and Development (AMED), Tokyo, Japan.,Faculty of Life and Environmental Sciences, University of Yamanashi, Yamanashi, Japan
| | - Haruka Tohara
- Gerodontology and Oral Rehabilitation, Department of Gerontology and Gerodontology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Naoyuki Miyasaka
- Department of Comprehensive Reproductive Medicine, Tokyo Medical and Dental University, Tokyo, Japan
| | - Tomomitsu Hirota
- Research Center for Medical Science, Core Research Facilities for Basic Science (Molecular Genetics), The Jikei University School of Medicine, Tokyo, Japan
| | - Mayumi Tamari
- Research Center for Medical Science, Core Research Facilities for Basic Science (Molecular Genetics), The Jikei University School of Medicine, Tokyo, Japan
| | - Yuichi Izumi
- Department of Periodontology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
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29
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Wang J, Ran Q, Zeng HR, Wang L, Hu CJ, Huang QW. Cellular stress response mechanisms of Rhizoma coptidis: a systematic review. Chin Med 2018; 13:27. [PMID: 29930696 PMCID: PMC5992750 DOI: 10.1186/s13020-018-0184-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Accepted: 05/27/2018] [Indexed: 12/29/2022] Open
Abstract
Rhizoma coptidis has been used in China for thousands of years with the functions of heating dampness and purging fire detoxification. But the underlying molecular mechanisms of Rhizoma coptidis are still far from being fully elucidated. Alkaloids, especially berberine, coptisine and palmatine, are responsible for multiple pharmacological effects of Rhizoma coptidis. In this review, we studied on the effects and molecular mechanisms of Rhizoma coptidis on NF-κB/MAPK/PI3K–Akt/AMPK/ERS and oxidative stress pathways. Then we summarized the mechanisms of these alkaloid components of Rhizoma coptidis on cardiovascular and cerebrovascular diseases, diabetes and diabetic complications. Evidence presented in this review implicated that Rhizoma coptidis exerted beneficial effects on various diseases by regulation of NF-κB/MAPK/PI3K–Akt/AMPK/ERS and oxidative stress pathways, which support the clinical application of Rhizoma coptidis and offer references for future researches.
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Affiliation(s)
- Jin Wang
- College of Pharmacy, Chengdu University of Traditional Chinese Medicine, No. 1166, Liutai Road, Wenjiang District, Chengdu, 611137 China
| | - Qian Ran
- College of Pharmacy, Chengdu University of Traditional Chinese Medicine, No. 1166, Liutai Road, Wenjiang District, Chengdu, 611137 China
| | - Hai-Rong Zeng
- College of Pharmacy, Chengdu University of Traditional Chinese Medicine, No. 1166, Liutai Road, Wenjiang District, Chengdu, 611137 China
| | - Lin Wang
- College of Pharmacy, Chengdu University of Traditional Chinese Medicine, No. 1166, Liutai Road, Wenjiang District, Chengdu, 611137 China
| | - Chang-Jiang Hu
- College of Pharmacy, Chengdu University of Traditional Chinese Medicine, No. 1166, Liutai Road, Wenjiang District, Chengdu, 611137 China
| | - Qin-Wan Huang
- College of Pharmacy, Chengdu University of Traditional Chinese Medicine, No. 1166, Liutai Road, Wenjiang District, Chengdu, 611137 China
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30
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Naowaboot J, Wannasiri S, Pannangpetch P. Vernonia cinerea water extract improves insulin resistance in high-fat diet-induced obese mice. Nutr Res 2018; 56:51-60. [PMID: 30055774 DOI: 10.1016/j.nutres.2018.04.020] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Revised: 01/17/2018] [Accepted: 04/27/2018] [Indexed: 12/17/2022]
Abstract
Vernonia cinerea (V cinerea) is a plant distributed in grassy areas in Southeast Asia and has several pharmacological effects, including antidiabetic activity. However, the information available regarding the effect of V cinerea on insulin resistance in high-fat diet (HFD)-induced obese mice is not yet determined. We hypothesized that V cinerea water extract (VC) improves insulin sensitivity in HFD-induced obese mice by modulating both phosphatidylinositol-3-kinase (PI3K) and adenosine monophosphate-activated protein kinase (AMPK) pathways in liver, skeletal muscle, and adipose tissue. Obesity was induced in mice from the Institute for Cancer Research by feeding an HFD 188.28 kJ (45 kcal % lard fat) for 12 weeks. During the last 6 weeks of the HFD, obese mice were treated with VC (250 and 500 mg/kg). We found that VC at both doses significantly reduced the hyperglycemia, hyperinsulinemia, hyperleptinemia, and hyperlipidemia. Obese mice treated with VC could increase serum adiponectin but reduce the proinflammatory cytokines, tumor necrosis factor-α, and monocyte chemoattractant protein-1. The extracts decreased triglyceride storage in liver and skeletal muscle of obese mice. The average size of fat cells was smaller in VC-treated groups than that of the HFD group. The protein expressions of PI3K and AMPK pathways in liver, skeletal muscle, and adipose tissue were upregulated (increased phosphorylation of PI3K, protein kinase B, AMPK, and acetyl-CoA carboxylase) by VC treatment. Furthermore, the glucose transporter 4 was increased in muscle and adipose tissue in obese mice treated with VC. These data indicate that VC treatment stimulates phosphorylation of PI3K and AMPK pathways in liver, muscle, and adipose tissue. Stimulating these pathways may improve impaired glucose and lipid homeostasis in an HFD-induced obesity mouse model. Based on these findings, it appears that VC has potential as a functional food or therapeutic agent in management of insulin resistance related diseases, such as type 2 diabetes mellitus.
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Affiliation(s)
- Jarinyaporn Naowaboot
- Division of Pharmacology, Department of Preclinical Science, Faculty of Medicine, Thammasat University (Rangsit Campus), Pathum Thani 12120, Thailand.
| | - Supaporn Wannasiri
- Division of Physiology, Department of Preclinical Science, Faculty of Medicine, Thammasat University (Rangsit Campus), Pathum Thani 12120, Thailand
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Tang S, Wu W, Tang W, Ge Z, Wang H, Hong T, Zhu D, Bi Y. Suppression of Rho-kinase 1 is responsible for insulin regulation of the AMPK/SREBP-1c pathway in skeletal muscle cells exposed to palmitate. Acta Diabetol 2017; 54:635-644. [PMID: 28265821 DOI: 10.1007/s00592-017-0976-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Accepted: 02/19/2017] [Indexed: 11/28/2022]
Abstract
AIMS Clinical and experimental data suggest that early insulin therapy could reduce lipotoxicity in subjects and animal models with type 2 diabetes mellitus. However, the underlying mechanisms need to be clarified. Sterol regulatory element-binding protein 1c (SREBP-1c), which is negatively regulated by AMP-activated protein kinase (AMPK), plays a critical role in lipotoxicity and insulin resistance in skeletal muscle cells. Here, we investigated the effect and molecular mechanism of insulin intervention on the AMPK/SREBP-1c pathway in skeletal muscle cells with chronic exposure to palmitic acid (PA). METHODS Male C57BL/6 mice were fed with a high-fat diet for 12 weeks and were then treated with insulin, AMPK inhibitor, or metformin. L6 myotubes incubated with palmitic acid (PA) were treated with insulin or metformin. Dominant-negative AMPKα2 (DN-AMPKα2) lentivirus, AMPKα2 siRNA, or Rho-kinase 1 (ROCK1) siRNA were transfected into PA-treated L6 myotubes. RESULTS We found that the ability of PA to stimulate SREBP-1c and inhibit AMPK was reversed by insulin in L6 cells. Moreover, DN-AMPKα2 lentivirus and AMPKα2 siRNA were transfected into PA-treated L6 myotubes, and the decrease in SREBP-1c expression caused by insulin was blocked by AMPK inhibition independent of the phosphatidylinositol-4,5-biphosphate-3-kinase (PI3K)/AKT pathway. The serine/threonine kinase Rho-kinase (ROCK) 1, a downstream effector of the small G protein RhoA, was activated by PA. Interestingly, knockdown of ROCK1 by siRNA blocked the downregulation of AMPK phosphorylation under PA-treated L6 myotubes, which indicated that ROCK1 mediated the effect of insulin action on AMPK. CONCLUSIONS Our study indicated that insulin reduced lipotoxicity via ROCK1 and then improved AMPK/SREBP-1c signaling in skeletal muscle under PA-induced insulin resistance.
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Affiliation(s)
- Sunyinyan Tang
- Department of Endocrinology, Drum Tower Hospital Affiliated to the Nanjing University Medical School, Nanjing, Jiangsu, People's Republic of China
| | - Wenjun Wu
- Department of Endocrinology, Wuxi People's Hospital of Nanjing Medical University, Wuxi, Jiangsu, People's Republic of China
| | - Wenjuan Tang
- Department of Endocrinology, Drum Tower Hospital Affiliated to the Nanjing University Medical School, Nanjing, Jiangsu, People's Republic of China
| | - Zhijuan Ge
- Department of Endocrinology, Drum Tower Hospital Affiliated to the Nanjing University Medical School, Nanjing, Jiangsu, People's Republic of China
| | - Hongdong Wang
- Department of Endocrinology, Drum Tower Hospital Affiliated to the Nanjing University Medical School, Nanjing, Jiangsu, People's Republic of China
| | - Ting Hong
- Department of Endocrinology, Drum Tower Hospital Affiliated to the Nanjing University Medical School, Nanjing, Jiangsu, People's Republic of China
| | - Dalong Zhu
- Department of Endocrinology, Drum Tower Hospital Affiliated to the Nanjing University Medical School, Nanjing, Jiangsu, People's Republic of China.
| | - Yan Bi
- Department of Endocrinology, Drum Tower Hospital Affiliated to the Nanjing University Medical School, Nanjing, Jiangsu, People's Republic of China.
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Wu W, Feng J, Jiang D, Zhou X, Jiang Q, Cai M, Wang X, Shan T, Wang Y. AMPK regulates lipid accumulation in skeletal muscle cells through FTO-dependent demethylation of N 6-methyladenosine. Sci Rep 2017; 7:41606. [PMID: 28176824 PMCID: PMC5296945 DOI: 10.1038/srep41606] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Accepted: 12/22/2016] [Indexed: 11/28/2022] Open
Abstract
Skeletal muscle plays important roles in whole-body energy homeostasis. Excessive skeletal muscle lipid accumulation is associated with some metabolic diseases such as obesity and Type 2 Diabetes. The energy sensor AMPK (AMP-activated protein kinase) is a key regulator of skeletal muscle lipid metabolism, but the precise regulatory mechanism remains to be elucidated. Here, we provide a novel mechanism by which AMPK regulates skeletal muscle lipid accumulation through fat mass and obesity-associated protein (FTO)-dependent demethylation of N6-methyladenosine (m6A). We confirmed an inverse correlation between AMPK and skeletal muscle lipid content. Moreover, inhibition of AMPK enhanced lipid accumulation, while activation of AMPK reduced lipid accumulation in skeletal muscle cells. Notably, we found that mRNA m6A methylation levels were inversely correlated with lipid content in skeletal muscle. Furthermore, AMPK positively regulated the m6A methylation levels of mRNA, which could negatively regulate lipid accumulation in C2C12. At the molecular level, we demonstrated that AMPK regulated lipid accumulation in skeletal muscle cells by regulating FTO expression and FTO-dependent demethylation of m6A. Together, these results provide a novel regulatory mechanism of AMPK on lipid metabolism in skeletal muscle cells and suggest the possibility of controlling skeletal muscle lipid deposition by targeting AMPK or using m6A related drugs.
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Affiliation(s)
- Weiche Wu
- College of Animal Science, Zhejiang University, Key Laboratory of Animal Nutrition & Feed Sciences, Ministry of Agriculture; Zhejiang Provincial Laboratory of Feed and Animal Nutrition, No. 866 Yuhangtang Road, Hangzhou, Zhejiang, 310058, P. R. China
| | - Jie Feng
- College of Animal Science, Zhejiang University, Key Laboratory of Animal Nutrition & Feed Sciences, Ministry of Agriculture; Zhejiang Provincial Laboratory of Feed and Animal Nutrition, No. 866 Yuhangtang Road, Hangzhou, Zhejiang, 310058, P. R. China
| | - Denghu Jiang
- College of Animal Science, Zhejiang University, Key Laboratory of Animal Nutrition & Feed Sciences, Ministry of Agriculture; Zhejiang Provincial Laboratory of Feed and Animal Nutrition, No. 866 Yuhangtang Road, Hangzhou, Zhejiang, 310058, P. R. China
| | - Xihong Zhou
- Institute of Subtropical Agriculture, The Chinese Academy of Science, Changsha, Hunan 410125, P. R. China
| | - Qin Jiang
- College of Animal Science, Zhejiang University, Key Laboratory of Animal Nutrition & Feed Sciences, Ministry of Agriculture; Zhejiang Provincial Laboratory of Feed and Animal Nutrition, No. 866 Yuhangtang Road, Hangzhou, Zhejiang, 310058, P. R. China
| | - Min Cai
- College of Animal Science, Zhejiang University, Key Laboratory of Animal Nutrition & Feed Sciences, Ministry of Agriculture; Zhejiang Provincial Laboratory of Feed and Animal Nutrition, No. 866 Yuhangtang Road, Hangzhou, Zhejiang, 310058, P. R. China
| | - Xinxia Wang
- College of Animal Science, Zhejiang University, Key Laboratory of Animal Nutrition & Feed Sciences, Ministry of Agriculture; Zhejiang Provincial Laboratory of Feed and Animal Nutrition, No. 866 Yuhangtang Road, Hangzhou, Zhejiang, 310058, P. R. China
| | - Tizhong Shan
- College of Animal Science, Zhejiang University, Key Laboratory of Animal Nutrition & Feed Sciences, Ministry of Agriculture; Zhejiang Provincial Laboratory of Feed and Animal Nutrition, No. 866 Yuhangtang Road, Hangzhou, Zhejiang, 310058, P. R. China
| | - Yizhen Wang
- College of Animal Science, Zhejiang University, Key Laboratory of Animal Nutrition & Feed Sciences, Ministry of Agriculture; Zhejiang Provincial Laboratory of Feed and Animal Nutrition, No. 866 Yuhangtang Road, Hangzhou, Zhejiang, 310058, P. R. China
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Kitamura K, Takamura Y, Iwamoto T, Nomura M, Iwasaki H, Ohdera M, Murakoshi M, Sugiyama K, Matsuyama K, Manabe Y, Fujii NL, Fushiki T. Dammarane-type triterpene extracts of Panax notoginseng root ameliorates hyperglycemia and insulin sensitivity by enhancing glucose uptake in skeletal muscle. Biosci Biotechnol Biochem 2017; 81:335-342. [PMID: 27771987 DOI: 10.1080/09168451.2016.1246173] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Accepted: 09/17/2016] [Indexed: 10/20/2022]
Abstract
Skeletal muscle is an important organ for controlling the development of type 2 diabetes. We discovered Panax notoginseng roots as a candidate to improve hyperglycemia through in vitro muscle cells screening test. Saponins are considered as the active ingredients of ginseng. However, in the body, saponins are converted to dammarane-type triterpenes, which may account for the anti-hyperglycemic activity. We developed a method for producing a dammarane-type triterpene extract (DTE) from Panax notoginseng roots and investigated the extract's potential anti-hyperglycemic activity. We found that DTE had stronger suppressive activity on blood glucose levels than the saponin extract (SE) did in KK-Ay mice. Additionally, DTE improved oral glucose tolerance, insulin sensitivity, glucose uptake, and Akt phosphorylation in skeletal muscle. These results suggest that DTE is a promising agent for controlling hyperglycemia by enhancing glucose uptake in skeletal muscle.
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Affiliation(s)
- Kumiko Kitamura
- a Research and Development Headquarters, Lion Corporation , Odawara , Japan
| | - Yusuke Takamura
- a Research and Development Headquarters, Lion Corporation , Odawara , Japan
| | - Taku Iwamoto
- a Research and Development Headquarters, Lion Corporation , Odawara , Japan
| | - Mitsuru Nomura
- a Research and Development Headquarters, Lion Corporation , Odawara , Japan
| | - Hideaki Iwasaki
- a Research and Development Headquarters, Lion Corporation , Odawara , Japan
| | - Motoyasu Ohdera
- a Research and Development Headquarters, Lion Corporation , Odawara , Japan
| | - Michiaki Murakoshi
- a Research and Development Headquarters, Lion Corporation , Odawara , Japan
| | - Keikichi Sugiyama
- a Research and Development Headquarters, Lion Corporation , Odawara , Japan
| | - Kazuki Matsuyama
- b Department of Health Promotion Sciences , Graduate School of Human Health Sciences, Tokyo Metropolitan University , Hachioji , Japan
| | - Yasuko Manabe
- b Department of Health Promotion Sciences , Graduate School of Human Health Sciences, Tokyo Metropolitan University , Hachioji , Japan
| | - Nobuharu L Fujii
- b Department of Health Promotion Sciences , Graduate School of Human Health Sciences, Tokyo Metropolitan University , Hachioji , Japan
| | - Tohru Fushiki
- c Division of Food Science and Biotechnology , Graduate School of Agriculture, Kyoto University , Kyoto , Japan
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Naowaboot J, Piyabhan P. Senna alata leaf extract restores insulin sensitivity in high-fat diet-induced obese mice. CLINICAL PHYTOSCIENCE 2017. [DOI: 10.1186/s40816-016-0032-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
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Yuan H, Wang T, Niu Y, Liu X, Fu L. AMP-activated protein kinase-mediated expression of heat shock protein beta 1 enhanced insulin sensitivity in the skeletal muscle. FEBS Lett 2016; 591:97-108. [PMID: 27928820 DOI: 10.1002/1873-3468.12516] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Revised: 10/18/2016] [Accepted: 11/24/2016] [Indexed: 11/12/2022]
Abstract
Activation of AMP-activated protein kinase (AMPK) has been viewed as an important target for the treatment of insulin resistance. Here, by proteomic analysis, we found that expression of heat shock protein beta-1 (HSPB1) was induced by the AMP analog 5-aminoimidazole-4-carboxamide 1-β-D-ribofuranoside in palmitate-induced insulin-resistant cells. Overexpression of AMPKα2, or activation of AMPKα via acute/chronic exercise training, increased HSPB1 expression in the skeletal muscle. In AMPKα2-/- mice, HSPB1 expression was downregulated in the quadriceps muscles. Exercise did not increase HSPB1 expression in AMPKα2-/- mice. Moreover, overexpression of HSPB1 enhanced insulin sensitivity in palmitate-induced insulin-resistant cells and restored metabolic phenotypes associated with defective AMPK. Finally, HSPB1 was required for AMPK-mediated activation of the class IIa histone deacetylases and glucose uptake in the skeletal muscle. Our results demonstrate that AMPK-mediated HSPB1 expression enhanced insulin sensitivity in the skeletal muscle.
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Affiliation(s)
- Hairui Yuan
- Department of Physiology and Pathophysiology, School of Basic Medical Science, Tianjin Medical University, China.,Key Laboratory of Hormones and Development (Ministry of Health), Tianjin Key Laboratory of Metabolic Diseases, Tianjin Metabolic Diseases Hospital & Tianjin Institute of Endocrinology, Tianjin Medical University, China
| | - Tianyi Wang
- Department of Physiology and Pathophysiology, School of Basic Medical Science, Tianjin Medical University, China
| | - Yanmei Niu
- Department of Rehabilitation and Sports Medicine, Tianjin Medical University, China
| | - Xiaolei Liu
- Department of Physiology and Pathophysiology, School of Basic Medical Science, Tianjin Medical University, China
| | - Li Fu
- Department of Physiology and Pathophysiology, School of Basic Medical Science, Tianjin Medical University, China
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Inada A, Fujii NL, Inada O, Higaki Y, Furuichi Y, Nabeshima YI. Effects of 17β-Estradiol and Androgen on Glucose Metabolism in Skeletal Muscle. Endocrinology 2016; 157:4691-4705. [PMID: 27653033 DOI: 10.1210/en.2016-1261] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Diabetes develops predominantly in males in experimental models, and extensive evidence suggests that 17β-estradiol (E2) modulates progression of diabetes in humans. We previously developed a severely diabetic transgenic (Tg) mouse model by β-cell-specific overexpression of inducible cAMP early repressor (ICER) and found that male ICER-Tg mice exhibit sustained severe hyperglycemia, but female ICER-Tg mice gradually became normoglycemic with aging. This implies that differences in circulating androgen and E2 levels might influence skeletal muscle glucose uptake and glycemic status. Here we examined whether a decrease of androgen or E2 excess can improve muscle glucose uptake in hyperglycemic male ICER-Tg mice and, conversely, whether a decrease of E2 or androgen excess can elevate blood glucose levels and impair muscle glucose uptake in normoglycemic female ICER-Tg mice. We treated hyperglycemic male ICER-Tg mice with orchiectomy (ORX) or ORX+E2 pellet implantation and normoglycemic female ICER-Tg mice with ovariectomy (OVX) or OVX+5α-DHT pellet implantation to alter the androgen to E2 ratio. ORX+E2 treatment of male ICER-Tg mice caused a rapid drop in blood glucose via both a dramatic increase of β-cells and significantly improved muscle glucose uptake due to the induction of glucose transporter type 4 (GLUT4) expression and translocation of GLUT4 to the cell membrane. In contrast, OVX+5α-DHT-treated female ICER-Tg mice showed an elevation of blood glucose without any decrease of β-cells; instead, they showed decreased muscle glucose uptake due to decreased activation of serine/threonine-specific protein kinase AKT and GLUT4 expression. These findings suggest that androgen (5α-DHT) promotes insulin resistance in females, whereas E2 improves insulin sensitivity in severely diabetic male mice.
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Affiliation(s)
- Akari Inada
- Laboratory of Molecular Life Science (A.I., Y.N.), Institute of Biomedical Research and Innovation, Kobe 650-0047, Japan; Department of Diabetes and Genes (A.I., O.I.), Advanced Medical Initiatives, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan; Department of Health Promotion Sciences (N.L.F.), Graduate School of Human Health Sciences, Tokyo Metropolitan University, Tokyo 192-0397, Japan; and Faculty of Sports and Health Science (Y.H.) and Institute for Physical Activity (Y.H.), Fukuoka University, Fukuoka 814-0180, Japan
| | - Nobuharu L Fujii
- Laboratory of Molecular Life Science (A.I., Y.N.), Institute of Biomedical Research and Innovation, Kobe 650-0047, Japan; Department of Diabetes and Genes (A.I., O.I.), Advanced Medical Initiatives, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan; Department of Health Promotion Sciences (N.L.F.), Graduate School of Human Health Sciences, Tokyo Metropolitan University, Tokyo 192-0397, Japan; and Faculty of Sports and Health Science (Y.H.) and Institute for Physical Activity (Y.H.), Fukuoka University, Fukuoka 814-0180, Japan
| | - Oogi Inada
- Laboratory of Molecular Life Science (A.I., Y.N.), Institute of Biomedical Research and Innovation, Kobe 650-0047, Japan; Department of Diabetes and Genes (A.I., O.I.), Advanced Medical Initiatives, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan; Department of Health Promotion Sciences (N.L.F.), Graduate School of Human Health Sciences, Tokyo Metropolitan University, Tokyo 192-0397, Japan; and Faculty of Sports and Health Science (Y.H.) and Institute for Physical Activity (Y.H.), Fukuoka University, Fukuoka 814-0180, Japan
| | - Yasuki Higaki
- Laboratory of Molecular Life Science (A.I., Y.N.), Institute of Biomedical Research and Innovation, Kobe 650-0047, Japan; Department of Diabetes and Genes (A.I., O.I.), Advanced Medical Initiatives, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan; Department of Health Promotion Sciences (N.L.F.), Graduate School of Human Health Sciences, Tokyo Metropolitan University, Tokyo 192-0397, Japan; and Faculty of Sports and Health Science (Y.H.) and Institute for Physical Activity (Y.H.), Fukuoka University, Fukuoka 814-0180, Japan
| | - Yasuro Furuichi
- Laboratory of Molecular Life Science (A.I., Y.N.), Institute of Biomedical Research and Innovation, Kobe 650-0047, Japan; Department of Diabetes and Genes (A.I., O.I.), Advanced Medical Initiatives, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan; Department of Health Promotion Sciences (N.L.F.), Graduate School of Human Health Sciences, Tokyo Metropolitan University, Tokyo 192-0397, Japan; and Faculty of Sports and Health Science (Y.H.) and Institute for Physical Activity (Y.H.), Fukuoka University, Fukuoka 814-0180, Japan
| | - Yo-Ichi Nabeshima
- Laboratory of Molecular Life Science (A.I., Y.N.), Institute of Biomedical Research and Innovation, Kobe 650-0047, Japan; Department of Diabetes and Genes (A.I., O.I.), Advanced Medical Initiatives, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan; Department of Health Promotion Sciences (N.L.F.), Graduate School of Human Health Sciences, Tokyo Metropolitan University, Tokyo 192-0397, Japan; and Faculty of Sports and Health Science (Y.H.) and Institute for Physical Activity (Y.H.), Fukuoka University, Fukuoka 814-0180, Japan
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AAV-mediated Sirt1 overexpression in skeletal muscle activates oxidative capacity but does not prevent insulin resistance. MOLECULAR THERAPY-METHODS & CLINICAL DEVELOPMENT 2016; 5:16072. [PMID: 27909699 PMCID: PMC5111573 DOI: 10.1038/mtm.2016.72] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Revised: 09/15/2016] [Accepted: 09/29/2016] [Indexed: 12/14/2022]
Abstract
Type 2 diabetes is characterized by triglyceride accumulation and reduced lipid oxidation capacity in skeletal muscle. SIRT1 is a key protein in the regulation of lipid oxidation and its expression is reduced in the skeletal muscle of insulin resistant mice. In this tissue, Sirt1 up-regulates the expression of genes involved in oxidative metabolism and improves mitochondrial function mainly through PPARGC1 deacetylation. Here we examined whether Sirt1 overexpression mediated by adeno-associated viral vectors of serotype 1 (AAV1) specifically in skeletal muscle can counteract the development of insulin resistance induced by a high fat diet in mice. AAV1-Sirt1-treated mice showed up-regulated expression of key genes related to β-oxidation together with increased levels of phosphorylated AMP protein kinase. Moreover, SIRT1 overexpression in skeletal muscle also increased basal phosphorylated levels of AKT. However, AAV1-Sirt1 treatment was not enough to prevent high fat diet-induced obesity and insulin resistance. Although Sirt1 gene transfer to skeletal muscle induced changes at the muscular level related with lipid and glucose homeostasis, our data indicate that overexpression of SIRT1 in skeletal muscle is not enough to improve whole-body insulin resistance and that suggests that SIRT1 has to be increased in other metabolic tissues to prevent insulin resistance.
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Zhai K, Gu L, Yang Z, Mao Y, Jin M, Chang Y, Yuan Q, Leblais V, Wang H, Fischmeister R, Ji G. RNA-binding protein CUGBP1 regulates insulin secretion via activation of phosphodiesterase 3B in mice. Diabetologia 2016; 59:1959-67. [PMID: 27255754 DOI: 10.1007/s00125-016-4005-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2016] [Accepted: 05/16/2016] [Indexed: 01/17/2023]
Abstract
AIMS/HYPOTHESIS CUG-binding protein 1 (CUGBP1) is a multifunctional RNA-binding protein that regulates RNA processing at several stages including translation, deadenylation and alternative splicing, as well as RNA stability. Recent studies indicate that CUGBP1 may play a role in metabolic disorders. Our objective was to examine its role in endocrine pancreas function through gain- and loss-of-function experiments and to further decipher the underlying molecular mechanisms. METHODS A mouse model in which type 2 diabetes was induced by a high-fat diet (HFD; 60% energy from fat) and mice on a standard chow diet (10% energy from fat) were compared. Pancreas-specific CUGBP1 overexpression and knockdown mice were generated. Different lengths of the phosphodiesterase subtype 3B (PDE3B) 3' untranslated region (UTR) were cloned for luciferase reporter analysis. Purified CUGBP1 protein was used for gel shift experiments. RESULTS CUGBP1 is present in rodent islets and in beta cell lines; it is overexpressed in the islets of diabetic mice. Compared with control mice, the plasma insulin level after a glucose load was significantly lower and glucose clearance was greatly delayed in mice with pancreas-specific CUGBP1 overexpression; the opposite results were obtained upon pancreas-specific CUGBP1 knockdown. Glucose- and glucagon-like peptide1 (GLP-1)-stimulated insulin secretion was significantly attenuated in mouse islets upon CUGBP1 overexpression. This was associated with a strong decrease in intracellular cAMP levels, pointing to a potential role for cAMP PDEs. CUGBP1 overexpression had no effect on the mRNA levels of PDE1A, 1C, 2A, 3A, 4A, 4B, 4D, 7A and 8B subtypes, but resulted in increased PDE3B expression. CUGBP1 was found to directly bind to a specific ATTTGTT sequence residing in the 3' UTR of PDE3B and stabilised PDE3B mRNA. In the presence of the PDE3 inhibitor cilostamide, glucose- and GLP-1-stimulated insulin secretion was no longer reduced by CUGBP1 overexpression. Similar to CUGBP1, PDE3B was overexpressed in the islets of diabetic mice. CONCLUSIONS/INTERPRETATION We conclude that CUGBP1 is a critical regulator of insulin secretion via activating PDE3B. Repressing this protein might provide a potential strategy for treating type 2 diabetes.
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Affiliation(s)
- Kui Zhai
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, People's Republic of China
| | - Lei Gu
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, People's Republic of China
| | - Zhiguang Yang
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, People's Republic of China
| | - Yang Mao
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, People's Republic of China
| | - Meng Jin
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, People's Republic of China
| | - Yan Chang
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, People's Republic of China
| | - Qi Yuan
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, People's Republic of China
| | - Veronique Leblais
- Inserm, UMR-S 1180, Faculté de Pharmacie, Université Paris-Sud, 5 rue J.-B. Clément, 92296, Châtenay-Malabry, France
| | - Huiwen Wang
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, People's Republic of China
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, People's Republic of China
| | - Rodolphe Fischmeister
- Inserm, UMR-S 1180, Faculté de Pharmacie, Université Paris-Sud, 5 rue J.-B. Clément, 92296, Châtenay-Malabry, France.
| | - Guangju Ji
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, People's Republic of China.
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Slámová K, Papoušek F, Janovská P, Kopecký J, Kolář F. Adverse effects of AMP-activated protein kinase alpha2-subunit deletion and high-fat diet on heart function and ischemic tolerance in aged female mice. Physiol Res 2015; 65:33-42. [PMID: 26596312 DOI: 10.33549/physiolres.932979] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
AMP-activated protein kinase (AMPK) plays a role in metabolic regulation under stress conditions, and inadequate AMPK signaling may be also involved in aging process. The aim was to find out whether AMPK alpha2-subunit deletion affects heart function and ischemic tolerance of adult and aged mice. AMPK alpha2(-/-) (KO) and wild type (WT) female mice were compared at the age of 6 and 18 months. KO mice exhibited subtle myocardial AMPK alpha2-subunit protein level, but no difference in AMPK alpha1-subunit was detected between the strains. Both alpha1- and alpha2-subunits of AMPK and their phosphorylation decreased with advanced age. Left ventricular fractional shortening was lower in KO than in WT mice of both age groups and this difference was maintained after high-fat feeding. Infarct size induced by global ischemia/reperfusion of isolated hearts was similar in both strains at 6 months of age. Aged WT but not KO mice exhibited improved ischemic tolerance compared with the younger group. High-fat feeding for 6 months during aging abolished the infarct size-reduction in WT without affecting KO animals; nevertheless, the extent of injury remained larger in KO mice. The results demonstrate that adverse effects of AMPK alpha2-subunit deletion and high-fat feeding on heart function and myocardial ischemic tolerance in aged female mice are not additive.
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Affiliation(s)
- K Slámová
- Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic.
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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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Allerton TD, Primeaux SD. High-fat diet differentially regulates metabolic parameters in obesity-resistant S5B/Pl rats and obesity-prone Osborne-Mendel rats. Can J Physiol Pharmacol 2015; 94:206-215. [PMID: 26641537 DOI: 10.1139/cjpp-2015-0141] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The current experiment tested the hypothesis that consumption of a high-fat diet (HFD) would differentially affect metabolic parameters in obesity-prone Osborne-Mendel (OM) and obesity-resistant S5B/Pl (S5B) rats. In OM rats consuming a HFD, an increase in HFD intake, body mass, and percent fat mass, and a HFD-induced decrease in metabolic rate and energy expenditure were demonstrated. In S5B rats consuming a HFD, no change in percent body fat or HFD intake was demonstrated and HFD increased metabolic rate and energy expenditure. To assess whether HFD differentially altered skeletal muscle markers of metabolism in OM and S5B rats, the expression of the transporters, CD36 and GLUT4, and the energy sensors, AMPK and PPARγ, in the gastrocnemius muscle was measured. Oxidation and lipid accumulation in the gastrocnemius muscle was histologically determined. Consumption of a HFD decreased phosphorylated AMPK and PPARγ expression in the skeletal muscle of obesity-prone OM rats. Lipid accumulation in skeletal muscle was significantly higher in OM rats fed a HFD. Overall, these data suggest that the differential response to HFD on metabolic rate, energy expenditure, and phosphorylated AMPK and PPARγ in OM and S5B rats, may partially account for differences in the susceptibility to develop obesity.
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Affiliation(s)
- Timothy D Allerton
- a Department of Physiology, Louisiana State University Health Sciences Center-New Orleans, 1901 Perdido Street, New Orleans, LA 70112, USA
| | - Stefany D Primeaux
- a Department of Physiology, Louisiana State University Health Sciences Center-New Orleans, 1901 Perdido Street, New Orleans, LA 70112, USA.,b Joint Diabetes, Endocrinology & Metabolism Program, Pennington Biomedical Research Center, Baton Rouge, LA 70808, USA
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Abstract
The prevalence of obesity has been increasing worldwide over the past 30 years and is a major public health concern. Obesity is known to be associated with metabolic disturbances including insulin resistance and inflammation; however, there is a subset of obese subjects who have normal metabolic profiles, and they have been identified as the metabolically healthy obese (MHO). Several studies have described MHO as obese individuals who have high levels of insulin sensitivity and the absence of diabetes, dyslipidemia, or hypertension. The prevalence of MHO varies from 20 to 30% among obese individuals. This review will discuss the MHO phenotype; the differences between MHO and metabolically unhealthy obese (MUO) individuals; and the possible underlying mechanisms including adipocyte differentiation, immune regulation, and cellular energy metabolism.
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Affiliation(s)
- Patchaya Boonchaya-anant
- Section of Endocrinology, Diabetes and Nutrition, Department of Medicine, Boston University School of Medicine, Robinson Building 4400, 88 East Newton Street, Boston Medical Center, Boston, MA, 02118, USA,
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Mull AJ, Berhanu TK, Roberts NW, Heydemann A. The Murphy Roths Large (MRL) mouse strain is naturally resistant to high fat diet-induced hyperglycemia. Metabolism 2014; 63:1577-1586. [PMID: 25308446 PMCID: PMC4252560 DOI: 10.1016/j.metabol.2014.09.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2014] [Revised: 09/02/2014] [Accepted: 09/19/2014] [Indexed: 12/12/2022]
Abstract
OBJECTIVE Due to their previously identified naturally and chronically increased levels of skeletal muscle pAMPK we hypothesized and now investigated whether the MRL/MpJ (MRL) mice would be resistant to high fat diet (HFD)-induced metabolic changes. MATERIALS/METHODS Three-week old male MRL and control C57Bl/6 (B6) mice were randomly assigned to 12weeks of high fat diets (HFD) or control diets (CD). Weekly animal masses and fasting blood glucose measurements were acquired. During the last week of diet intervention, fasted animals were subjected to glucose and insulin tolerance tests. At harvest, tissues were dissected for immunoblots and serum was collected for ELISA assays. RESULTS The MRL mouse strain is known for its ability to regenerate ear punch wounds, cardiac cryoinjury, and skeletal muscle disease. Despite gaining weight and increasing their fat deposits the MRL mice were resistant to all other indicators of HFD-induced metabolic alterations assayed. Only the HFD-B6 mice displayed fasting hyperglycemia, hyperinsulinemia and hypersensitivity to glucose challenge. HFD-MRL mice were indistinguishable from their CD-MRL counterparts in these metrics. Skeletal muscles from the HFD-MRL contained heightened levels of pAMPK, even above their CD counterparts. CONCLUSIONS The MRL mouse strain is the first naturally occurring mouse strain that we are aware of that is resistant to HFD-induced metabolic changes. Furthermore, the increased pAMPK suggests a proximal mechanism for these beneficial metabolic differences. We further hypothesize that these metabolic differences and plasticity provide the basis for the MRL mouse strain's super healing characteristics. This project's ultimate aim is to identify novel therapeutic targets, which specifically increase pAMPK.
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Affiliation(s)
- Aaron J. Mull
- Department of Physiology and Biophysics, The University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Tirsit K. Berhanu
- Department of Physiology and Biophysics, The University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Nathan W. Roberts
- Department of Physiology and Biophysics, The University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Ahlke Heydemann
- Department of Physiology and Biophysics, The University of Illinois at Chicago, Chicago, IL 60612, USA
- Center for Cardiovascular Research, The University of Illinois at Chicago, Chicago, IL 60612, USA
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Abbott MJ, Turcotte LP. AMPK-α2 is involved in exercise training-induced adaptations in insulin-stimulated metabolism in skeletal muscle following high-fat diet. J Appl Physiol (1985) 2014; 117:869-79. [DOI: 10.1152/japplphysiol.01380.2013] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
AMP-activated protein kinase (AMPK) has been studied extensively and postulated to be a target for the treatment and/or prevention of metabolic disorders such as insulin resistance. Exercise training has been deemed a beneficial treatment for obesity and insulin resistance. Furthermore, exercise is a feasible method to combat high-fat diet (HFD)-induced alterations in insulin sensitivity. The purpose of this study was to determine whether AMPK-α2 activity is required to gain beneficial effects of exercise training with high-fat feeding. Wild-type (WT) and AMPK-α2 dominant-negative (DN) male mice were fed standard diet (SD), underwent voluntary wheel running (TR), fed HFD, or trained with HFD (TR + HFD). By week 6, TR, irrespective of genotype, decreased blood glucose and increased citrate synthase activity in both diet groups and decreased insulin levels in HFD groups. Hindlimb perfusions were performed, and, in WT mice with SD, TR increased insulin-mediated palmitate uptake (76.7%) and oxidation (>2-fold). These training-induced changes were not observed in the DN mice. With HFD, TR decreased palmitate oxidation (61–64%) in both WT and DN and increased palmitate uptake (112%) in the WT with no effects on palmitate uptake in the DN. With SD, TR increased ERK1/2 and JNK1/2 phosphorylation, regardless of genotype. With HFD, TR reduced JNK1/2 phosphorylation, regardless of genotype, carnitine palmitoyltransferase 1 expression in WT, and CD36 expression in both DN and WT. These data suggest that low AMPK-α2 signaling disrupts, in part, the exercise training-induced adaptations in insulin-stimulated metabolism in skeletal muscle following HFD.
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Affiliation(s)
- Marcia J. Abbott
- Department of Biological Sciences, Human and Evolutionary Biology Section, Dana and David Dornsife College of Arts, Letters, and Sciences, University of Southern California, Los Angeles, California; and
- Crean College of Health and Behavioral Sciences, Chapman University, Orange, California
| | - Lorraine P. Turcotte
- Department of Biological Sciences, Human and Evolutionary Biology Section, Dana and David Dornsife College of Arts, Letters, and Sciences, University of Southern California, Los Angeles, California; and
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Valentine RJ, Coughlan KA, Ruderman NB, Saha AK. Insulin inhibits AMPK activity and phosphorylates AMPK Ser⁴⁸⁵/⁴⁹¹ through Akt in hepatocytes, myotubes and incubated rat skeletal muscle. Arch Biochem Biophys 2014; 562:62-9. [PMID: 25172224 DOI: 10.1016/j.abb.2014.08.013] [Citation(s) in RCA: 101] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Revised: 08/15/2014] [Accepted: 08/18/2014] [Indexed: 01/16/2023]
Abstract
Recent studies have highlighted the importance of an inhibitory phosphorylation site, Ser(485/491), on the α-subunit of AMP-activated protein kinase (AMPK); however, little is known about the regulation of this site in liver and skeletal muscle. We examined whether the inhibitory effects of insulin on AMPK activity may be mediated through the phosphorylation of this inhibitory Ser(485/491) site in hepatocytes, myotubes and incubated skeletal muscle. HepG2 and C2C12 cells were stimulated with or without insulin for 15-min. Similarly, rat extensor digitorum longus (EDL) muscles were treated +/- insulin for 10-min. Insulin significantly increased Ser(485/491) p-AMPK under all conditions, resulting in a subsequent reduction in AMPK activity, ranging from 40% to 70%, despite no change in p-AMPK Thr(172). Akt inhibition both attenuated the increase in Ser(485/491) p-AMPK caused by insulin, and prevented the decrease in AMPK activity. Similarly, the growth factor IGF-1 stimulated Ser(485/491) AMPK phosphorylation, and this too was blunted by inhibition of Akt. Inhibition of the mTOR pathway with rapamycin, however, had no effect on insulin-stimulated Ser(485/491) p-AMPK. These data suggest that insulin and IGF-1 diminish AMPK activity in hepatocytes and muscle, most likely through Akt activation and the inhibitory phosphorylation of Ser(485/491) on its α-subunit.
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Affiliation(s)
- Rudy J Valentine
- Endocrinology, Diabetes, and Nutrition Section, Department of Medicine, Boston University School of Medicine, Boston, MA, USA
| | - Kimberly A Coughlan
- Endocrinology, Diabetes, and Nutrition Section, Department of Medicine, Boston University School of Medicine, Boston, MA, USA
| | - Neil B Ruderman
- Endocrinology, Diabetes, and Nutrition Section, Department of Medicine, Boston University School of Medicine, Boston, MA, USA
| | - Asish K Saha
- Endocrinology, Diabetes, and Nutrition Section, Department of Medicine, Boston University School of Medicine, Boston, MA, USA.
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Caffeamide 36-13 Regulates the Antidiabetic and Hypolipidemic Signs of High-Fat-Fed Mice on Glucose Transporter 4, AMPK Phosphorylation, and Regulated Hepatic Glucose Production. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2014; 2014:821569. [PMID: 25140189 PMCID: PMC4130186 DOI: 10.1155/2014/821569] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/19/2014] [Accepted: 07/03/2014] [Indexed: 01/14/2023]
Abstract
This study was to investigate the antidiabetic and antihyperlipidemic effects of (E)-3-[3, 4-dihydroxyphenyl-1-(piperidin-1-yl)prop-2-en-1-one] (36-13) (TS), one of caffeic acid amide derivatives, on high-fat (HF-) fed mice. The C57BL/6J mice were randomly divided into the control (CON) group and the experimental group, which was firstly fed a HF diet for 8 weeks. Then, the HF group was subdivided into four groups and was given TS orally (including two doses) or rosiglitazone (Rosi) or vehicle for 4 weeks. Blood, skeletal muscle, and tissues were examined by measuring glycaemia and dyslipidemia-associated events. TS effectively prevented HF diet-induced increases in the levels of blood glucose, triglyceride, insulin, leptin, and free fatty acid (FFA) and weights of visceral fa; moreover, adipocytes in the visceral depots showed a reduction in size. TS treatment significantly increased the protein contents of glucose transporter 4 (GLUT4) in skeletal muscle; TS also significantly enhanced Akt phosphorylation in liver, whereas it reduced the expressions of phosphoenolpyruvate carboxykinase (PEPCK) and glucose-6-phosphatase (G6Pase). Moreover, TS enhanced phosphorylation of AMP-activated protein kinase (phospho-AMPK) both in skeletal muscle and liver tissue. Therefore, it is possible that the activation of AMPK by TS resulted in enhanced glucose uptake in skeletal muscle, contrasting with diminished gluconeogenesis in liver. TS exhibits hypolipidemic effect by decreasing the expressions of fatty acid synthase (FAS). Thus, antidiabetic properties of TS occurred as a result of decreased hepatic glucose production by PEPCK and G6Pase downregulation and improved insulin sensitization. Thus, amelioration of diabetic and dyslipidemic state by TS in HF-fed mice occurred by regulation of GLUT4, G6Pase, and FAS and phosphorylation of AMPK.
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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: 205] [Impact Index Per Article: 20.5] [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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Fan W, Atkins AR, Yu RT, Downes M, Evans RM. Road to exercise mimetics: targeting nuclear receptors in skeletal muscle. J Mol Endocrinol 2013; 51:T87-T100. [PMID: 24280961 PMCID: PMC3936671 DOI: 10.1530/jme-13-0258] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Skeletal muscle is the largest organ in the human body and is the major site for energy expenditure. It exhibits remarkable plasticity in response to physiological stimuli such as exercise. Physical exercise remodels skeletal muscle and enhances its capability to burn calories, which has been shown to be beneficial for many clinical conditions including the metabolic syndrome and cancer. Nuclear receptors (NRs) comprise a class of transcription factors found only in metazoans that regulate major biological processes such as reproduction, development, and metabolism. Recent studies have demonstrated crucial roles for NRs and their co-regulators in the regulation of skeletal muscle energy metabolism and exercise-induced muscle remodeling. While nothing can fully replace exercise, development of exercise mimetics that enhance or even substitute for the beneficial effects of physical exercise would be of great benefit. The unique property of NRs that allows modulation by endogenous or synthetic ligands makes them bona fide therapeutic targets. In this review, we present an overview of the current understanding of the role of NRs and their co-regulators in skeletal muscle oxidative metabolism and summarize recent progress in the development of exercise mimetics that target NRs and their co-regulators.
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Affiliation(s)
- Weiwei Fan
- Gene Expression Laboratory Howard Hughes Medical Institute, Salk Institute for Biological Studies, La Jolla, California 92037, USA
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Brandauer J, Vienberg SG, Andersen MA, Ringholm S, Risis S, Larsen PS, Kristensen JM, Frøsig C, Leick L, Fentz J, Jørgensen S, Kiens B, Wojtaszewski JFP, Richter EA, Zierath JR, Goodyear LJ, Pilegaard H, Treebak JT. AMP-activated protein kinase regulates nicotinamide phosphoribosyl transferase expression in skeletal muscle. J Physiol 2013; 591:5207-20. [PMID: 23918774 DOI: 10.1113/jphysiol.2013.259515] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Deacetylases such as sirtuins (SIRTs) convert NAD to nicotinamide (NAM). Nicotinamide phosphoribosyl transferase (Nampt) is the rate-limiting enzyme in the NAD salvage pathway responsible for converting NAM to NAD to maintain cellular redox state. Activation of AMP-activated protein kinase (AMPK) increases SIRT activity by elevating NAD levels. As NAM directly inhibits SIRTs, increased Nampt activation or expression could be a metabolic stress response. Evidence suggests that AMPK regulates Nampt mRNA content, but whether repeated AMPK activation is necessary for increasing Nampt protein levels is unknown. To this end, we assessed whether exercise training- or 5-amino-1-β-D-ribofuranosyl-imidazole-4-carboxamide (AICAR)-mediated increases in skeletal muscle Nampt abundance are AMPK dependent. One-legged knee-extensor exercise training in humans increased Nampt protein by 16% (P < 0.05) in the trained, but not the untrained leg. Moreover, increases in Nampt mRNA following acute exercise or AICAR treatment (P < 0.05 for both) were maintained in mouse skeletal muscle lacking a functional AMPK α2 subunit. Nampt protein was reduced in skeletal muscle of sedentary AMPK α2 kinase dead (KD), but 6.5 weeks of endurance exercise training increased skeletal muscle Nampt protein to a similar extent in both wild-type (WT) (24%) and AMPK α2 KD (18%) mice. In contrast, 4 weeks of daily AICAR treatment increased Nampt protein in skeletal muscle in WT mice (27%), but this effect did not occur in AMPK α2 KD mice. In conclusion, functional α2-containing AMPK heterotrimers are required for elevation of skeletal muscle Nampt protein, but not mRNA induction. These findings suggest AMPK plays a post-translational role in the regulation of skeletal muscle Nampt protein abundance, and further indicate that the regulation of cellular energy charge and nutrient sensing is mechanistically related.
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Affiliation(s)
- Josef Brandauer
- J. T. Treebak: University of Copenhagen, NNF Center for Basic Metabolic Research, Blegdamsvej 3b, 6.6.28, Copenhagen DK2200, Denmark.
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50
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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: 604] [Impact Index Per Article: 54.9] [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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