CLOCK and BMAL1 Regulate Muscle Insulin Sensitivity via SIRT1 in Male Mice

Circadian misalignment induces insulin resistance in both human and animal models, and skeletal muscle is the largest organ response to insulin. However, how circadian clock regulates muscle insulin sensitivity and the underlying molecular mechanisms are still largely unknown. Here we show circadian locomotor output cycles kaput (CLOCK) and brain and muscle aryl hydrocarbon receptor nuclear translocator-like protein (BMAL)-1, two core circadian transcription factors, are down-regulated in insulin-resistant C2C12 myotubes and mouse skeletal muscle. Furthermore, insulin signaling is attenuated in the skeletal muscle of ClockΔ19/Δ19 mice, and knockdown of CLOCK or BMAL1 by small interfering RNAs induces insulin resistance in C2C12 myotubes. Consistently, ectopic expression of CLOCK and BMAL1 improves insulin sensitivity in C2C12 myotubes. Moreover, CLOCK and BMAL1 regulate the expression of sirtuin 1 (SIRT1), an important regulator of insulin sensitivity, in C2C12 myotubes and mouse skeletal muscle, and two E-box elements in Sirt1 promoter are responsible for its CLOCK- and BMAL1-dependent transcription in muscle cells. Further studies show that CLOCK and BMAL1 regulate muscle insulin sensitivity through SIRT1. In addition, we find that BMAL1 and SIRT1 are decreased in the muscle of mice maintained in constant darkness, and resveratrol supplementation activates SIRT1 and improves insulin sensitivity. All these data demonstrate that CLOCK and BMAL1 regulate muscle insulin sensitivity via SIRT1, and activation of SIRT1 might be a potential valuable strategy to attenuate muscle insulin resistance related to circadian misalignment.

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Hepatokine ERAP1 impairs skeletal muscle insulin sensitivity via ADRB2/PKA pathway

10.21203/rs.3.rs-37586/v1 ◽

2020 ◽

Author(s):

Feifan Guo ◽

Yuguo Niu ◽

Haizhou Jiang ◽

Hanrui Yin ◽

Fenfen Wang ◽

...

Keyword(s):

Insulin Resistance ◽

Skeletal Muscle ◽

Insulin Sensitivity ◽

Neutralizing Antibodies ◽

Leptin Receptor ◽

Whole Body ◽

C2c12 Myotubes ◽

Insulin Resistant ◽

Skeletal Muscle Insulin Sensitivity ◽

Pka Pathway

Abstract The current study aimed to investigate the role of endoplasmic reticulum aminopeptidase 1 (ERAP1), a novel hepatokine, in whole-body glucose metabolism. Here, we found that hepatic ERAP1 levels were increased in insulin-resistant leptin-receptor-mutated (db/db) and high-fat diet (HFD)-fed mice. Consistently, hepatic ERAP1 overexpression attenuated skeletal muscle (SM) insulin sensitivity, whereas knockdown ameliorated SM insulin resistance. Furthermore, serum and hepatic ERAP1 levels were positively correlated, and recombinant mouse ERAP1 or conditioned medium with high ERAP1 content (CM-ERAP1) attenuated insulin signaling in C2C12 myotubes, and CM-ERAP1 or HFD-induced insulin resistance was blocked by ERAP1 neutralizing antibodies. Mechanistically, ERAP1 reduced ADRB2 expression and interrupted ADRB2-dependent signaling in C2C12 myotubes. Finally, ERAP1 inhibition via global knockout or the inhibitor thimerosal improved insulin sensitivity. Together, ERAP1 is a hepatokine that impairs SM and whole-body insulin sensitivity, and its inhibition might provide a therapeutic strategy for diabetes, particularly for those with SM insulin resistance.

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Oleate Blocks Palmitate-Induced Abnormal Lipid Distribution, Endoplasmic Reticulum Expansion and Stress, and Insulin Resistance in Skeletal Muscle

Endocrinology ◽

10.1210/en.2010-1369 ◽

2011 ◽

Vol 152 (6) ◽

pp. 2206-2218 ◽

Cited By ~ 98

Author(s):

Gong Peng ◽

Linghai Li ◽

Yanbo Liu ◽

Jing Pu ◽

Shuyan Zhang ◽

...

Keyword(s):

Insulin Resistance ◽

Skeletal Muscle ◽

Fatty Acids ◽

Endoplasmic Reticulum ◽

Insulin Sensitivity ◽

Er Stress ◽

Molecular Mechanisms ◽

Dietary Fatty Acids ◽

Akt Phosphorylation ◽

Stress Relieving

Pathological elevation of plasma fatty acids reduces insulin sensitivity. Although several regulation pathways have been reported, the molecular mechanisms of insulin sensitivity remain elusive, especially in skeletal muscle where most glucose is consumed. This study focuses on how two major dietary fatty acids affect insulin signaling in skeletal muscle cells. Palmitic acid (PA) not only reduced insulin-stimulated phosphorylation of Akt but also induced endoplasmic reticulum (ER) expansion and ER stress. Relieving ER stress using 4-phenyl butyric acid blocked PA-mediated protein kinase R-like ER kinase phosphorylation and ER expansion and reversed the inhibitory effect of PA on insulin-stimulated Akt phosphorylation. Importantly, oleic acid (OA) could also recover PA-reduced Akt phosphorylation and abolish both PA-mediated ER expansion and ER stress. The competition between these two fatty acids was further verified in rat skeletal muscle using venous fatty acid infusion. 3H-labeled PA was converted mainly to active lipids (phospholipids and diacylglycerol) in the absence of OA, but to triacylglycerol in the presence of OA. Subcellular triacylglycerol and adipocyte differentiation-related protein from PA-treated cells cofractionated with the ER in the absence of OA but switched to the low-density fraction in the presence of OA. Taken together, these data suggest that the PA-mediated lipid composition and localization may cause ER expansion and consequently cause ER stress and insulin resistance in skeletal muscle.

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Low-Frequency Electroacupuncture Improves Insulin Sensitivity in Obese Diabetic Mice through Activation of SIRT1/PGC-1αin Skeletal Muscle

Evidence-based Complementary and Alternative Medicine ◽

10.1155/2011/735297 ◽

2011 ◽

Vol 2011 ◽

pp. 1-9 ◽

Cited By ~ 30

Author(s):

Fengxia Liang ◽

Rui Chen ◽

Atsushi Nakagawa ◽

Makoto Nishizawa ◽

Shinichi Tsuda ◽

...

Keyword(s):

Insulin Resistance ◽

Skeletal Muscle ◽

Insulin Sensitivity ◽

Fasting Blood Glucose ◽

Low Frequency ◽

Tolerance Test ◽

Sirtuin 1 ◽

Peroxisome Proliferator ◽

Peroxisome Proliferator Activated Receptor ◽

Obesity And Diabetes

Electroacupuncture (EA) has been observed to reduce insulin resistance in obesity and diabetes. However, the biochemical mechanism underlying this effect remains unclear. This study investigated the effects of low-frequency EA on metabolic action in genetically obese and type 2 diabetic db/db mice. Nine-week-old db/m and db/db mice were randomly divided into four groups, namely, db/m, db/m + EA, db/db, and db/db + EA. db/m + EA and db/db + EA mice received 3-Hz electroacupuncture five times weekly for eight consecutive weeks. In db/db mice, EA tempered the increase in fasting blood glucose, food intake, and body mass and maintained insulin levels. In EA-treated db/db mice, improved insulin sensitivity was established through intraperitoneal insulin tolerance test. EA was likewise observed to decrease free fatty acid levels in db/db mice; it increased protein expression in skeletal muscle Sirtuin 1 (SIRT1) and induced gene expression of peroxisome proliferator-activated receptor coactivator (PGC-), nuclear respiratory factor 1 (NRF1), and acyl-CoA oxidase (ACOX). These results indicated that EA offers a beneficial effect on insulin resistance in obese and diabetic db/db mice, at least partly, via stimulation of SIRT1/PGC-, thus resulting in improved insulin signal.

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Modulation of SIRT1-Foxo1 Signaling axis by Resveratrol: Implications in Skeletal Muscle Aging and Insulin Resistance

Cellular Physiology and Biochemistry ◽

10.1159/000369718 ◽

2015 ◽

Vol 35 (2) ◽

pp. 541-552 ◽

Cited By ~ 53

Author(s):

Thomas K. Sin ◽

Benjamin Y. Yung ◽

Parco M. Siu

Keyword(s):

Insulin Resistance ◽

Skeletal Muscle ◽

Insulin Sensitivity ◽

Insulin Signaling ◽

Pyruvate Dehydrogenase ◽

Glycolytic Enzyme ◽

Negative Regulator ◽

Sirtuin 1 ◽

Diabetic Patients ◽

Muscle Aging

Aging individuals and diabetic patients often exhibit concomitant reductions of skeletal muscle mass/strength and insulin sensitivity, suggesting an intimate link between muscle aging and insulin resistance. Foxo1, a member of the FOXO transcription factor family, is an important player in insulin signaling due to its inhibitory role in glucose uptake and utilization in skeletal muscle. Phosphorylation of Foxo1 is thought to mitigate the transactivation of pyruvate dehydrogenase lipoamide kinase 4 (PDK4), which is a negative regulator of the glycolytic enzyme pyruvate dehydrogenase (PDH). In contrast, how aging would regulate acetylation/deacetylation machineries and glucose utilization in skeletal muscle through the Foxo1/PDH axis remains largely undetermined. Accumulating body of evidence have shown that resveratrol, a natural polyphenol in grapes and red wine, activates the longevity-related protein sirtuin 1 (SIRT1) and augments insulin sensitivity in addition to its well-documented effects on mitochondrial energetics. The present review summarizes the role of Foxo1/SIRT1 in insulin signaling in skeletal muscle and proposes the insight that activation of SIRT1 deacetylase activity to deacetylate and suppress the Foxo1-induced transactivation of PDK4 may represent an anti-hyperglycemic mechanism of resveratrol in aging skeletal muscle.

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Exercise Counterbalances Rho/ROCK2 Signaling Impairment in the Skeletal Muscle and Ameliorates Insulin Sensitivity in Obese Mice

Frontiers in Immunology ◽

10.3389/fimmu.2021.702025 ◽

2021 ◽

Vol 12 ◽

Author(s):

Vitor R. Muñoz ◽

Rafael C. Gaspar ◽

Matheus B. Severino ◽

Ana P. A. Macêdo ◽

Fernando M. Simabuco ◽

...

Keyword(s):

Skeletal Muscle ◽

Insulin Sensitivity ◽

Physical Exercise ◽

Glucose Uptake ◽

Molecular Mechanisms ◽

Tyrosine Phosphatase ◽

C2c12 Myotubes ◽

Obese Mice ◽

Skeletal Muscle Glucose Uptake ◽

The Impact

Physical exercise is considered a fundamental strategy in improving insulin sensitivity and glucose uptake in skeletal muscle. However, the molecular mechanisms underlying this regulation, primarily on skeletal muscle glucose uptake, are not fully understood. Recent evidence has shown that Rho-kinase (ROCK) isoforms play a pivotal role in regulating skeletal muscle glucose uptake and systemic glucose homeostasis. The current study evaluated the effect of physical exercise on ROCK2 signaling in skeletal muscle of insulin-resistant obese animals. Physiological (ITT) and molecular analysis (immunoblotting, and RT-qPCR) were performed. The contents of RhoA and ROCK2 protein were decreased in skeletal muscle of obese mice compared to control mice but were restored to normal levels in response to physical exercise. The exercised animals also showed higher phosphorylation of insulin receptor substrate 1 (IRS1 Serine 632/635) and protein kinase B (Akt) in the skeletal muscle. However, phosphatase and tensin homolog (PTEN) and protein-tyrosine phosphatase-1B (PTP-1B), both inhibitory regulators for insulin action, were increased in obesity but decreased after exercise. The impact of ROCK2 action on muscle insulin signaling is further underscored by the fact that impaired IRS1 and Akt phosphorylation caused by palmitate in C2C12 myotubes was entirely restored by ROCK2 overexpression. These results suggest that the exercise-induced upregulation of RhoA-ROCK2 signaling in skeletal muscle is associated with increased systemic insulin sensitivity in obese mice and further implicate that muscle ROCK2 could be a potential target for treating obesity-linked metabolic disorders.

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Relationship between insulin sensitivity and gene expression in human skeletal muscle

10.21203/rs.3.rs-42125/v2 ◽

2020 ◽

Author(s):

Hemang Parikh ◽

Targ Elgzyri ◽

Amra Alibegovic ◽

Natalie Hiscock ◽

Ola Ekström ◽

...

Keyword(s):

Gene Expression ◽

Insulin Resistance ◽

Skeletal Muscle ◽

Lipid Metabolism ◽

Insulin Sensitivity ◽

Human Skeletal Muscle ◽

Molecular Mechanisms ◽

Independent Study ◽

Nutrient Sensing ◽

Model Assessment

Abstract Background: Insulin resistance in skeletal muscle is a key feature of the pre-diabetic state, hypertension, dyslipidemia, cardiovascular diseases and also predicts type 2 diabetes. However, the underlying molecular mechanisms are still poorly understood. Methods: To explore these mechanisms, we related global skeletal muscle gene expression profiling of 38 non-diabetic men to a surrogate measure of insulin sensitivity, i.e. homeostatic model assessment of insulin resistance (HOMA-IR). Results: We identified 70 genes positively and 110 genes inversely correlated with insulin sensitivity in human skeletal muscle, identifying autophagy-related genes as positively correlated with insulin sensitivity. Replication in an independent study of 9 non-diabetic men resulted in 10 overlapping genes that strongly correlated with insulin sensitivity, including SIRT2, involved in lipid metabolism, and FBXW5 that regulates mammalian target-of-rapamycin (mTOR) and autophagy. The expressions of SIRT2 and FBXW5 were also positively correlated with the expression of key genes promoting the phenotype of an insulin sensitive myocyte e.g. PPARGC1A. Conclusions: These data suggest that activation of genes involved in lipid metabolism, e.g. SIRT2, and genes regulating autophagy and mTOR signaling, e.g. FBXW5, are associated with increased insulin sensitivity in human skeletal muscle, reflecting a highly flexible nutrient sensing.

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eEF1A2 exacerbated insulin resistance in male skeletal muscle via PKCβ and ER stress

Journal of Endocrinology ◽

10.1530/joe-19-0051 ◽

2020 ◽

Vol 244 (1) ◽

pp. 25-40 ◽

Cited By ~ 2

Author(s):

Meng Guo ◽

Yuna Li ◽

Yan Wang ◽

Zhenkun Li ◽

Xiaohong Li ◽

...

Keyword(s):

Insulin Resistance ◽

Skeletal Muscle ◽

Insulin Sensitivity ◽

Er Stress ◽

Lentiviral Vector ◽

C2c12 Myotubes ◽

Mongolian Gerbils ◽

Suppression Subtractive Hybridisation ◽

Translation Elongation ◽

Insulin Resistant

Recent studies raise the possibility that eukaryotic translation elongation factor 1 alpha (eEF1A) may play a role in metabolism. One isoform, eEF1A2, is specifically expressed in skeletal muscle, heart and brain. It regulates translation elongation and signal transduction. Nonetheless, eEF1A2’s function in skeletal muscle glucose metabolism remains unclear. In the present study, suppression subtractive hybridisation showed a decrease in Eef1a2 transcripts in the skeletal muscle of diabetic Mongolian gerbils. This was confirmed at mRNA and protein levels in hyperglycaemic gerbils, and in db/db and high-fat diet-fed mice. Further, this downregulation was independent of Eef1a2 promoter methylation. Interestingly, adeno-associated virus-mediated eEF1A2 overexpression in skeletal muscle aggravated fasting hyperglycaemia, hyperinsulinaemia and glucose intolerance in male diabetic gerbils but not in female gerbil models. The overexpression of eEF1A2 in skeletal muscle also resulted in promoted serum glucose levels and insulin resistance in male db/db mice. Up- and downregulation of eEF1A2 by lentiviral vector transfection confirmed its inhibitory effect on insulin-stimulated glucose uptake and signalling transduction in C2C12 myotubes with palmitate (PA)-induced insulin resistance. Furthermore, eEF1A2 bound PKCβ and increased its activation in the cytoplasm, whereas suppression of PKCβ by an inhibitor attenuated eEF1A2-mediated impairment of insulin sensitivity in insulin-resistant myotubes. Endoplasmic reticulum (ER) stress was elevated by eEF1A2, whereas suppression of ER stress or JNK partially restored insulin sensitivity in PA-treated myotubes. Additionally, eEF1A2 inhibited lipogenesis and lipid utilisation in insulin-resistant skeletal muscle. Collectively, we demonstrated that eEF1A2 exacerbates insulin resistance in male murine skeletal muscle via PKCβ and ER stress.

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Loss of hnRNP A1 in murine skeletal muscle exacerbates high-fat diet-induced onset of insulin resistance and hepatic steatosis

Journal of Molecular Cell Biology ◽

10.1093/jmcb/mjz050 ◽

2019 ◽

Vol 12 (4) ◽

pp. 277-290 ◽

Cited By ~ 2

Author(s):

Mingxia Zhao ◽

Lihong Shen ◽

Zijun Ouyang ◽

Manru Li ◽

Guoliang Deng ◽

...

Keyword(s):

Insulin Resistance ◽

Skeletal Muscle ◽

Insulin Sensitivity ◽

Hepatic Steatosis ◽

Muscle Tissue ◽

High Fat Diet ◽

Glycogen Synthesis ◽

C2c12 Myotubes ◽

Hnrnp A1 ◽

High Fat

Abstract Impairment of glucose (Glu) uptake and storage by skeletal muscle is a prime risk factor for the development of metabolic diseases. Heterogeneous nuclear ribonucleoprotein A1 (hnRNP A1) is a highly abundant RNA-binding protein that has been implicated in diverse cellular functions. The aim of this study was to investigate the function of hnRNP A1 on muscle tissue insulin sensitivity and systemic Glu homeostasis. Our results showed that conditional deletion of hnRNP A1 in the muscle gave rise to a severe insulin resistance phenotype in mice fed a high-fat diet (HFD). Conditional knockout mice fed a HFD showed exacerbated obesity, insulin resistance, and hepatic steatosis. In vitro interference of hnRNP A1 in C2C12 myotubes impaired insulin signal transduction and inhibited Glu uptake, whereas hnRNP A1 overexpression in C2C12 myotubes protected against insulin resistance induced by supraphysiological concentrations of insulin. The expression and stability of glycogen synthase (gys1) mRNA were also decreased in the absence of hnRNP A1. Mechanistically, hnRNP A1 interacted with gys1 and stabilized its mRNA, thereby promoting glycogen synthesis and maintaining the insulin sensitivity in muscle tissue. Taken together, our findings are the first to show that reduced expression of hnRNP A1 in skeletal muscle affects the metabolic properties and systemic insulin sensitivity by inhibiting glycogen synthesis.

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Mechanisms of insulin resistance by simvastatin in C2C12 myotubes and in mouse skeletal muscle

Biochemical Pharmacology ◽

10.1016/j.bcp.2019.02.025 ◽

2019 ◽

Vol 164 ◽

pp. 23-33 ◽

Cited By ~ 8

Author(s):

Gerda M. Sanvee ◽

Miljenko V. Panajatovic ◽

Jamal Bouitbir ◽

Stephan Krähenbühl

Keyword(s):

Insulin Resistance ◽

Skeletal Muscle ◽

C2c12 Myotubes ◽

Mouse Skeletal Muscle

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Relationship between insulin sensitivity and gene expression in human skeletal muscle

BMC Endocrine Disorders ◽

10.1186/s12902-021-00687-9 ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Hemang M. Parikh ◽

Targ Elgzyri ◽

Amra Alibegovic ◽

Natalie Hiscock ◽

Ola Ekström ◽

...

Keyword(s):

Gene Expression ◽

Insulin Resistance ◽

Skeletal Muscle ◽

Lipid Metabolism ◽

Insulin Sensitivity ◽

Human Skeletal Muscle ◽

Molecular Mechanisms ◽

Independent Study ◽

Nutrient Sensing ◽

Model Assessment

Abstract Background Insulin resistance (IR) in skeletal muscle is a key feature of the pre-diabetic state, hypertension, dyslipidemia, cardiovascular diseases and also predicts type 2 diabetes. However, the underlying molecular mechanisms are still poorly understood. Methods To explore these mechanisms, we related global skeletal muscle gene expression profiling of 38 non-diabetic men to a surrogate measure of insulin sensitivity, i.e. homeostatic model assessment of insulin resistance (HOMA-IR). Results We identified 70 genes positively and 110 genes inversely correlated with insulin sensitivity in human skeletal muscle, identifying autophagy-related genes as positively correlated with insulin sensitivity. Replication in an independent study of 9 non-diabetic men resulted in 10 overlapping genes that strongly correlated with insulin sensitivity, including SIRT2, involved in lipid metabolism, and FBXW5 that regulates mammalian target-of-rapamycin (mTOR) and autophagy. The expressions of SIRT2 and FBXW5 were also positively correlated with the expression of key genes promoting the phenotype of an insulin sensitive myocyte e.g.PPARGC1A. Conclusions The muscle expression of 180 genes were correlated with insulin sensitivity. These data suggest that activation of genes involved in lipid metabolism, e.g.SIRT2, and genes regulating autophagy and mTOR signaling, e.g.FBXW5, are associated with increased insulin sensitivity in human skeletal muscle, reflecting a highly flexible nutrient sensing.

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