Abstract 1185: Role Of Sphingosine-1-Phosphate (S1P) In Insulin Signaling.

Circulation ◽  
2007 ◽  
Vol 116 (suppl_16) ◽  
Author(s):  
Suzanne M Nicholl ◽  
Elisa Roztocil ◽  
Mark G Davies
Keyword(s):  
Insulin Resistance ◽  
Skeletal Muscle ◽  
Glucose Uptake ◽  
Insulin Signaling ◽  
Receptor Expression ◽  
Serine Phosphorylation ◽  
Glucose Disposal ◽  
Sphingosine 1 Phosphate ◽  
Low Glucose

A failure to increase glucose disposal into peripheral tissues in response to insulin leads to impaired insulin signaling and an inability to uptake glucose leading to the onset of insulin resistance, a major contributing factor to diabetes. We examined the role of sphingosine-1-phosphate (S1P) in insulin signaling and its ability to regulate glucose uptake in skeletal muscle cells. S1P, a sphingolipid found in abundance in the circulation, has been implicated in not only mediating crosstalk with other signaling pathways but has also been implicated in insulin resistance. We hypothesize that S1P interacts with post-receptor insulin signaling to increase glucose disposal in an in vitro model of insulin resistance using differentiated mouse skeletal C2C12 myotubes. Our data demonstrates that S1P (10μM) increases basal glucose levels similar to that observed in response to insulin (100nM) under conditions of low glucose (** p < 0.005: n = 3). Conversely, high glucose conditions completely inhibit both insulin and S1P stimulated glucose uptake (*p < 0.01:n = 3). Pre-incubation with S1P does not augment insulin-induced glucose uptake (***p < 0.001:n = 3), suggesting that S1P does not act via a separate signaling pathway. This is confirmed by our data demonstrating that S1P-induced glucose uptake is abrogated by Cytochalasin B (*p < 0.001:n = 3). In addition, the PI3-K inhibitors, LY294002 and Wortmannin, the Akt inhibitor, AKT2 and the p38MAPK inhibitor, SB203580 significantly inhibited glucose uptake in response to S1P, demonstrating their importance in S1P-induced glucose uptake (*p < 0.05:n = 3). S1P2 and S1P3 receptor expression were upregulated in response to insulin (~2-fold over basal) under low glucose conditions suggesting that insulin may regulate S1P signaling via one or both of these receptors. S1P increased serine phosphorylation of IRS1, both at serine 307 and serines 636/639 maximally after 15 minutes of stimulation. This data has important clinical implications in patients with metabolic syndrome who have impaired skeletal muscle glucose disposal due to insulin resistance and will help guide present and future therapy for patients who have this rapidly growing disease.

scholarly journals Novel Insights and Mechanisms of Lipotoxicity-Driven Insulin Resistance

2020 ◽  
Vol 21 (17) ◽  
pp. 6358 ◽  
Author(s):  
Benjamin Lair ◽  
Claire Laurens ◽  
Bram Van Den Bosch ◽  
Cedric Moro
Keyword(s):  
Insulin Resistance ◽  
Skeletal Muscle ◽  
Acyl Chain ◽  
The Body ◽  
Glucose Disposal ◽  
Tissue Lipid ◽  
Lipid Species ◽  
Chain Composition

A large number of studies reported an association between elevated circulating and tissue lipid content and metabolic disorders in obesity, type 2 diabetes (T2D) and aging. This state of uncontrolled tissue lipid accumulation has been called lipotoxicity. It was later shown that excess lipid flux is mainly neutralized within lipid droplets as triglycerides, while several bioactive lipid species such as diacylglycerols (DAGs), ceramides and their derivatives have been mechanistically linked to the pathogenesis of insulin resistance (IR) by antagonizing insulin signaling and action in metabolic organs such as the liver and skeletal muscle. Skeletal muscle and the liver are the main sites of glucose disposal in the body and IR in these tissues plays a pivotal role in the development of T2D. In this review, we critically examine recent literature supporting a causal role of DAGs and ceramides in the development of IR. A particular emphasis is placed on transgenic mouse models with modulation of total DAG and ceramide pools, as well as on modulation of specific subspecies, in relation to insulin sensitivity. Collectively, although a wide number of studies converge towards the conclusion that both DAGs and ceramides cause IR in metabolic organs, there are still some uncertainties on their mechanisms of action. Recent studies reveal that subcellular localization and acyl chain composition are determinants in the biological activity of these lipotoxic lipids and should be further examined.

Prevention of skeletal muscle insulin resistance by dietary cod protein in high fat-fed rats

2001 ◽  
Vol 281 (1) ◽  
pp. E62-E71 ◽  
Author(s):  
Charles Lavigne ◽  
Frédéric Tremblay ◽  
Geneviève Asselin ◽  
Hélène Jacques ◽  
André Marette
Keyword(s):  
Insulin Resistance ◽  
Skeletal Muscle ◽  
Amino Acids ◽  
Glucose Uptake ◽  
Soy Protein ◽  
Whole Body ◽  
Glucose Disposal ◽  
High Fat ◽  
Muscle Insulin Resistance ◽  
Skeletal Muscle Insulin Resistance

In the present study, we tested the hypothesis that fish protein may represent a key constituent of fish with glucoregulatory activity. Three groups of rats were fed a high-fat diet in which the protein source was casein, fish (cod) protein, or soy protein; these groups were compared with a group of chow-fed controls. High-fat feeding led to severe whole body and skeletal muscle insulin resistance in casein- or soy protein-fed rats, as assessed by the euglycemic clamp technique coupled with measurements of 2-deoxy-d-[3H]glucose uptake rates by individual tissues. However, feeding cod protein fully prevented the development of insulin resistance in high fat-fed rats. These animals exhibited higher rates of insulin-mediated muscle glucose disposal that were comparable to those of chow-fed rats. The beneficial effects of cod protein occurred without any reductions in body weight gain, adipose tissue accretion, or expression of tumor necrosis factor-α in fat and muscle. Moreover, L6 myocytes exposed to cod protein-derived amino acids showed greater rates of insulin-stimulated glucose uptake compared with cells incubated with casein- or soy protein-derived amino acids. These data demonstrate that feeding cod protein prevents obesity-induced muscle insulin resistance in high fat-fed obese rats at least in part through a direct action of amino acids on insulin-stimulated glucose uptake in skeletal muscle cells.

Effect of Subtoxic DDT Exposure on Glucose Uptake and Insulin Signaling in Rat L6 Myoblast-Derived Myotubes

2019 ◽  
Vol 38 (4) ◽  
pp. 303-311 ◽  
Author(s):  
Vijay Kumar Singh ◽  
Sajib Kumar Sarkar ◽  
Alpana Saxena ◽  
Bidhan Chandra Koner
Keyword(s):  
Insulin Resistance ◽  
Glucose Uptake ◽  
Tyrosine Phosphorylation ◽  
Insulin Signaling ◽  
Messenger Rna ◽  
Insulin Receptors ◽  
Serine Phosphorylation ◽  
Enzyme Linked Immunosorbent Assay ◽  
Antioxidant Content ◽  
L6 Myoblast

Exposure to persistent organic pollutants including dichlorodiphenyltrichloroethane (DDT) induces insulin resistance. But the mechanism is not clearly known. The present study was designed to explore the effect of subtoxic DDT exposure on (1) insulin-stimulated glucose uptake, (2) malondialdehyde (MDA) level and total antioxidant content, (3) activation of redox sensitive kinases (RSKs), and (4) insulin signaling in rat L6 myoblast-derived myotubes. Exposure to 30 mg/L and 60 mg/L of DDT for 18 hours dose dependently decreased glucose uptake and antioxidant content in myotubes and increased MDA levels. The exposures did not alter tumor necrosis factor α (TNF-α) level as determined by enzyme-linked immunosorbent assay, despite decreased messenger RNA expression following DDT exposures. Phosphorylation of c-Jun N-terminal kinases and IκBα, an inhibitory component of nuclear factor κB (NFκB), was increased, suggesting activation of RSKs. The level of tyrosine phosphorylation of insulin receptor substrate 1 and serine phosphorylation of protein kinase B (Akt) on insulin stimulation decreased in myotubes with exposure to subtoxic concentrations of DDT, but there was no change in tyrosine phosphorylation level of insulin receptors. We conclude that subtoxic DDT exposure impairs insulin signaling and thereby induces insulin resistance in muscle cells. Data show that oxidative stress-induced activation of RSKs is responsible for impairment of insulin signaling on DDT exposure.

Oxidative stress impairs insulin signal in skeletal muscle and causes insulin resistance in postinfarct heart failure

2011 ◽  
Vol 300 (5) ◽  
pp. H1637-H1644 ◽  
Author(s):  
Yukihiro Ohta ◽  
Shintaro Kinugawa ◽  
Shouji Matsushima ◽  
Taisuke Ono ◽  
Mochamad A. Sobirin ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Heart Failure ◽  
Insulin Resistance ◽  
Skeletal Muscle ◽  
Insulin Signaling ◽  
Glucose Transporter ◽  
Diastolic Pressure ◽  
Left Ventricular ◽  
Serine Phosphorylation ◽  
Glucose Transporter 4

Insulin resistance has been shown to occur as a consequence of heart failure. However, its exact mechanisms in this setting remain unknown. We have previously reported that oxidative stress is enhanced in the skeletal muscle from mice with heart failure after myocardial infarction (MI) ( 30 ). This study is aimed to investigate whether insulin resistance in postinfarct heart failure is due to the impairment of insulin signaling in the skeletal muscle caused by oxidative stress. Mice were divided into four groups: sham operated (sham); sham treated with apocynin, an inhibitor of NAD(P)H oxidase activation (10 mmol/l in drinking water); MI; and MI treated with apocynin. After 4 wk, intraperitoneal insulin tolerance tests were performed, and skeletal muscle samples were obtained for insulin signaling measurements. MI mice showed left ventricular dilation and dysfunction by echocardiography and increased left ventricular end-diastolic pressure and lung weight. The decrease in glucose level after insulin load significantly attenuated in MI compared with sham. Insulin-stimulated serine phosphorylation of Akt and glucose transporter-4 translocation were decreased in MI mice by 61 and 23%, respectively. Apocynin ameliorated the increase in oxidative stress and NAD(P)H oxidase activities measured by the lucigenin assay in the skeletal muscle after MI. It also improved insulin resistance and inhibited the decrease of Akt phosphorylation and glucose transporter-4 translocation. Insulin resistance was induced by the direct impairment of insulin signaling in the skeletal muscle from postinfarct heart failure, which was associated with the enhanced oxidative stress via NAD(P)H oxidase.

Glucose infusion causes insulin resistance in skeletal muscle of rats without changes in Akt and AS160 phosphorylation

2007 ◽  
Vol 293 (5) ◽  
pp. E1358-E1364 ◽  
Author(s):  
Andrew J. Hoy ◽  
Clinton R. Bruce ◽  
Anna Cederberg ◽  
Nigel Turner ◽  
David E. James ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Skeletal Muscle ◽  
Glucose Uptake ◽  
Insulin Signaling ◽  
Glycogen Synthase ◽  
Glycogen Synthesis ◽  
Glucose Infusion ◽  
Metabolic Effects ◽  
Synthesis Rate ◽  
Muscle Sample

Hyperglycemia is a defining feature of Type 1 and 2 diabetes. Hyperglycemia also causes insulin resistance, and our group (Kraegen EW, Saha AK, Preston E, Wilks D, Hoy AJ, Cooney GJ, Ruderman NB. Am J Physiol Endocrinol Metab Endocrinol Metab 290: E471–E479, 2006) has recently demonstrated that hyperglycemia generated by glucose infusion results in insulin resistance after 5 h but not after 3 h. The aim of this study was to investigate possible mechanism(s) by which glucose infusion causes insulin resistance in skeletal muscle and in particular to examine whether this was associated with changes in insulin signaling. Hyperglycemia (∼10 mM) was produced in cannulated male Wistar rats for up to 5 h. The glucose infusion rate required to maintain this hyperglycemia progressively lessened over 5 h (by 25%, P < 0.0001 at 5 h) without any alteration in plasma insulin levels consistent with the development of insulin resistance. Muscle glucose uptake in vivo (44%; P < 0.05) and glycogen synthesis rate (52%; P < 0.001) were reduced after 5 h compared with after 3 h of infusion. Despite these changes, there was no decrease in the phosphorylation state of multiple insulin signaling intermediates [insulin receptor, Akt, AS160 (Akt substrate of 160 kDa), glycogen synthase kinase-3β] over the same time course. In isolated soleus strips taken from control or 1- or 5-h glucose-infused animals, insulin-stimulated 2-deoxyglucose transport was similar, but glycogen synthesis was significantly reduced in the 5-h muscle sample (68% vs. 1-h sample; P < 0.001). These results suggest that the reduced muscle glucose uptake in rats after 5 h of acute hyperglycemia is due more to the metabolic effects of excess glycogen storage than to a defect in insulin signaling or glucose transport.

NOD1 activation induces proinflammatory gene expression and insulin resistance in 3T3-L1 adipocytes

2011 ◽  
Vol 301 (4) ◽  
pp. E587-E598 ◽  
Author(s):  
Ling Zhao ◽  
Pan Hu ◽  
Yijun Zhou ◽  
Jaanki Purohit ◽  
Daniel Hwang
Keyword(s):  
Insulin Resistance ◽  
Glucose Uptake ◽  
Insulin Signaling ◽  
Serine Phosphorylation ◽  
Dependent Manner ◽  
Proinflammatory Response ◽  
Downstream Target ◽  
Synthetic Ligand ◽  
Underlying Mechanisms ◽  
Oligomerization Domain

Chronic inflammation is associated with obesity and insulin resistance; however, the underlying mechanisms are not fully understood. Pattern recognition receptors Toll-like receptors and nucleotide-oligomerization domain-containing proteins play critical roles in innate immune response. Here, we report that activation of nucleotide binding oligomerization domain-containing protein-1 (NOD1) in adipocytes induces proinflammatory response and impairs insulin signaling and insulin-induced glucose uptake. NOD1 and NOD2 mRNA are markedly increased in differentiated murine 3T3-L1 adipocytes and human primary adipocyte culture upon adipocyte conversion. Moreover, NOD1 mRNA is markedly increased only in the fat tissues in diet-induced obese mice, but not in genetically obese ob/ob mice. Stimulation of NOD1 with a synthetic ligand Tri-DAP induces proinflammatory chemokine MCP-1, RANTES, and cytokine TNF-α and MIP-2 (human IL-8 homolog) and IL-6 mRNA expression in 3T3-L1 adipocytes in a time- and dose-dependent manner. Similar proinflammatory profiles are observed in human primary adipocyte culture stimulated with Tri-DAP. Furthermore, NOD1 activation suppresses insulin signaling, as revealed by attenuated tyrosine phosphorylation and increased inhibitory serine phosphorylation, of IRS-1 and attenuated phosphorylation of Akt and downstream target GSK3α/3β, resulting in decreased insulin-induced glucose uptake in 3T3-L1 adipocytes. Together, our results suggest that NOD1 may play an important role in adipose inflammation and insulin resistance in diet-induced obesity.

(Pro)renin receptor in skeletal muscle is involved in the development of insulin resistance associated with postinfarct heart failure in mice

2014 ◽  
Vol 307 (6) ◽  
pp. E503-E514 ◽  
Author(s):  
Arata Fukushima ◽  
Shintaro Kinugawa ◽  
Shingo Takada ◽  
Shouji Matsushima ◽  
Mochamad Ali Sobirin ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Heart Failure ◽  
Insulin Resistance ◽  
Skeletal Muscle ◽  
Insulin Signaling ◽  
Glucose Transporter ◽  
Renin Angiotensin System ◽  
Left Ventricular ◽  
Serine Phosphorylation ◽  
Superoxide Production

We previously reported that insulin resistance was induced by the impairment of insulin signaling in the skeletal muscle from heart failure (HF) via NAD(P)H oxidase-dependent oxidative stress. (Pro)renin receptor [(P)RR] is involved in the activation of local renin-angiotensin system and subsequent oxidative stress. We thus examined whether (P)RR inhibitor, handle region peptide (HRP), could ameliorate insulin resistance in HF after myocardial infarction (MI) by improving oxidative stress and insulin signaling in the skeletal muscle. C57BL6J mice were divided into four groups: sham operated (Sham, n = 10), Sham treated with HRP (Sham+HRP, 0.1 mg·kg−1·day−1, n = 10), MI operated (MI, n = 10), and MI treated with HRP (MI+HRP, 0.1 mg/kg/day, n = 10). After 4 wk, MI mice showed left ventricular dysfunction, which was not affected by HRP. (P)RR was upregulated in the skeletal muscle after MI (149% of sham, P < 0.05). The decrease in plasma glucose after insulin load was smaller in MI than in Sham (21 ± 2 vs. 44 ± 3%, P < 0.05), and was greater in MI+HRP (38 ± 2%, P < 0.05) than in MI. Insulin-stimulated serine phosphorylation of Akt and glucose transporter 4 translocation were decreased in the skeletal muscle from MI by 48 and 49% of Sham, both of which were ameliorated in MI+HRP. Superoxide production and NAD(P)H oxidase activities were increased in MI, which was inhibited in MI+HRP. HRP ameliorated insulin resistance associated with HF by improving insulin signaling via the inhibition of NAD(P)H oxidase-induced superoxide production in the skeletal muscle. The (P)RR pathway is involved in the development of insulin resistance, at least in part, via the impairment of insulin signaling in the skeletal muscle from HF.

scholarly journals Tissue-Specific Difference in the Molecular Mechanisms for the Development of Acute Insulin Resistance after Injury

Endocrinology ◽  
2008 ◽  
Vol 150 (1) ◽  
pp. 24-32 ◽  
Author(s):  
Li Li ◽  
LaWanda H. Thompson ◽  
Ling Zhao ◽  
Joseph L. Messina
Keyword(s):  
Insulin Resistance ◽  
Skeletal Muscle ◽  
Insulin Receptor ◽  
Insulin Signaling ◽  
Molecular Mechanisms ◽  
Rapid Development ◽  
Serine Phosphorylation ◽  
Synthesis Inhibitor ◽  
Adult Rats ◽  
Counterregulatory Hormones

Acute insulin resistance occurs after injury, hemorrhage, infection, and critical illness. However, little is known about the development of this acute insulin-resistant state. In the current study, we found that insulin resistance develops rapidly in skeletal muscle, with the earliest insulin signaling defects at 60 min. However, defects in insulin signaling were measurable even earlier in liver, by as soon as 15 min after hemorrhage. To begin to understand the mechanisms for the development of acute insulin resistance, serine phosphorylation of insulin receptor substrate (IRS)-1 and c-Jun N-terminal kinase phosphorylation/activation was investigated. These markers (and possible contributors) of insulin resistance were increased in the liver after hemorrhage but not measurable in skeletal muscle. Because glucocorticoids are important counterregulatory hormones responsible for glucose homeostasis, a glucocorticoid synthesis inhibitor, metyrapone, and a glucocorticoid receptor antagonist, RU486, were administered to adult rats prior to hemorrhage. In the liver, the defects of insulin signaling after hemorrhage, including reduced tyrosine phosphorylation of the insulin receptor and IRS-1, association between IRS-1 and phosphatidylinositol 3-kinase and serine phosphorylation of Akt in response to insulin were not altered by pretreatment of rats with metyrapone or RU486. In contrast, hemorrhage-induced defects in insulin signaling were dramatically reversed in skeletal muscle, indicating a prevention of insulin resistance in muscle. These results suggest that distinct mechanisms for hemorrhage-induced acute insulin resistance are present in these two tissues and that glucocorticoids are involved in the rapid development of insulin resistance in skeletal muscle, but not in the liver, after hemorrhage. Glucocorticoids play a major role in the development of acute insulin resistance following hemorrhage in skeletal muscle, but not in the liver.

Revisiting the contribution of mitochondrial biology to the pathophysiology of skeletal muscle insulin resistance

2021 ◽  
Vol 478 (21) ◽  
pp. 3809-3826
Author(s):  
Sara M. Frangos ◽  
David J. Bishop ◽  
Graham P. Holloway
Keyword(s):  
Insulin Resistance ◽  
Skeletal Muscle ◽  
Insulin Signaling ◽  
Biological Effects ◽  
Primary Source ◽  
Central Component ◽  
Mitochondrial Content ◽  
High Lipid ◽  
Lipid Environment

While the etiology of type 2 diabetes is multifaceted, the induction of insulin resistance in skeletal muscle is a key phenomenon, and impairments in insulin signaling in this tissue directly contribute to hyperglycemia. Despite the lack of clarity regarding the specific mechanisms whereby insulin signaling is impaired, the key role of a high lipid environment within skeletal muscle has been recognized for decades. Many of the proposed mechanisms leading to the attenuation of insulin signaling — namely the accumulation of reactive lipids and the pathological production of reactive oxygen species (ROS), appear to rely on this high lipid environment. Mitochondrial biology is a central component to these processes, as these organelles are almost exclusively responsible for the oxidation and metabolism of lipids within skeletal muscle and are a primary source of ROS production. Classic studies have suggested that reductions in skeletal muscle mitochondrial content and/or function contribute to lipid-induced insulin resistance; however, in recent years the role of mitochondria in the pathophysiology of insulin resistance has been gradually re-evaluated to consider the biological effects of alterations in mitochondrial content. In this respect, while reductions in mitochondrial content are not required for the induction of insulin resistance, mechanisms that increase mitochondrial content are thought to enhance mitochondrial substrate sensitivity and submaximal adenosine diphosphate (ADP) kinetics. Thus, this review will describe the central role of a high lipid environment in the pathophysiology of insulin resistance, and present both classic and contemporary views of how mitochondrial biology contributes to insulin resistance in skeletal muscle.

Phorbol esters affect skeletal muscle glucose transport in a fiber type-specific manner

2004 ◽  
Vol 287 (2) ◽  
pp. E305-E309 ◽  
Author(s):  
David C. Wright ◽  
Paige C. Geiger ◽  
Mark J. Rheinheimer ◽  
Dong Ho Han ◽  
John O. Holloszy
Keyword(s):  
Insulin Resistance ◽  
Skeletal Muscle ◽  
Glucose Transport ◽  
Soleus Muscle ◽  
Insulin Signaling ◽  
Skeletal Muscles ◽  
Phorbol Esters ◽  
Serine Phosphorylation ◽  
Slow Twitch ◽  
Fast Twitch

Recent evidence has shown that activation of lipid-sensitive protein kinase C (PKC) isoforms leads to skeletal muscle insulin resistance. However, earlier studies demonstrated that phorbol esters increase glucose transport in skeletal muscle. The purpose of the present study was to try to resolve this discrepancy. Treatment with the phorbol ester 12-deoxyphorbol-13-phenylacetate 20-acetate (dPPA) led to an ∼3.5-fold increase in glucose transport in isolated fast-twitch epitrochlearis and flexor digitorum brevis muscles. Phorbol ester treatment was additive to a maximally effective concentration of insulin in fast-twitch skeletal muscles. Treatment with dPPA did not affect insulin signaling in the epitrochlearis. In contrast, phorbol esters had no effect on basal glucose transport and inhibited maximally insulin-stimulated glucose transport ∼50% in isolated slow-twitch soleus muscle. Furthermore, dPPA treatment inhibited the insulin-stimulated tyrosine phosphorylation of insulin receptor substrate (IRS)-1 and the threonine and serine phosphorylation of PKB by ∼50% in the soleus. dPPA treatment also caused serine phosphorylation of IRS-1 in the slow-twitch soleus muscle. In conclusion, our results show that phorbol esters stimulate glucose transport in fast-twitch skeletal muscles and inhibit insulin signaling in slow-twitch soleus muscle of rats. These findings suggest that mechanisms other than PKC activation mediate lipotoxicity-induced whole body insulin resistance.

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