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Hosokawa K, Hamada Y, Fujiya A, Murase M, Maekawa R, Niwa Y, Izumoto T, Seino Y, Tsunekawa S, Arima H. S100B impairs glycolysis via enhanced poly(ADP-ribosyl)ation of glyceraldehyde-3-phosphate dehydrogenase in rodent muscle cells. Am J Physiol Endocrinol Metab 2017; 312:E471-E481. [PMID: 28174179 DOI: 10.1152/ajpendo.00328.2016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Revised: 01/31/2017] [Accepted: 01/31/2017] [Indexed: 02/07/2023]
Abstract
S100 calcium-binding protein B (S100B), a multifunctional macromolecule mainly expressed in nerve tissues and adipocytes, has been suggested to contribute to the pathogenesis of obesity. To clarify the role of S100B in insulin action and glucose metabolism in peripheral tissues, we investigated the effect of S100B on glycolysis in myoblast and myotube cells. Rat myoblast L6 cells were treated with recombinant mouse S100B to examine glucose consumption, lactate production, glycogen accumulation, glycolytic metabolites and enzyme activity, insulin signaling, and poly(ADP-ribosyl)ation of glyceraldehyde-3-phosphate dehydrogenase (GAPDH). Glycolytic metabolites were investigated by enzyme assays or metabolome analysis, and insulin signaling was assessed by Western blot analysis. Enzyme activity and poly(ADP-ribosyl)ation of GAPDH was evaluated by an enzyme assay and immunoprecipitation followed by dot blot with an anti-poly(ADP-ribose) antibody, respectively. S100B significantly decreased glucose consumption, glucose analog uptake, and lactate production in L6 cells, in either the presence or absence of insulin. In contrast, S100B had no effect on glycogen accumulation and insulin signaling. Metabolome analysis revealed that S100B increased the concentration of glycolytic intermediates upstream of GAPDH. S100B impaired GAPDH activity and increased poly(ADP-ribosyl)ated GAPDH proteins. The effects of S100B on glucose metabolism were mostly canceled by a poly(ADP-ribose) polymerase inhibitor. Similar results were obtained in C2C12 myotube cells. We conclude that S100B as a humoral factor may impair glycolysis in muscle cells independent of insulin action, and the effect may be attributed to the inhibition of GAPDH activity from enhanced poly(ADP-ribosyl)ation of the enzyme.
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MESH Headings
- Animals
- Cell Line
- Cells, Cultured
- Enzyme Induction/drug effects
- Glyceraldehyde-3-Phosphate Dehydrogenases/antagonists & inhibitors
- Glyceraldehyde-3-Phosphate Dehydrogenases/genetics
- Glyceraldehyde-3-Phosphate Dehydrogenases/metabolism
- Glycolysis/drug effects
- Hexokinase/chemistry
- Hexokinase/genetics
- Hexokinase/metabolism
- Insulin/metabolism
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Muscle Fibers, Skeletal/drug effects
- Muscle Fibers, Skeletal/enzymology
- Muscle Fibers, Skeletal/metabolism
- Muscle, Skeletal/drug effects
- Muscle, Skeletal/enzymology
- Muscle, Skeletal/metabolism
- Myoblasts/drug effects
- Myoblasts/enzymology
- Myoblasts/metabolism
- Poly(ADP-ribose) Polymerase Inhibitors/pharmacology
- Poly(ADP-ribose) Polymerases/chemistry
- Poly(ADP-ribose) Polymerases/metabolism
- Protein Processing, Post-Translational/drug effects
- Rats
- Recombinant Proteins/metabolism
- S100 Calcium Binding Protein beta Subunit/genetics
- S100 Calcium Binding Protein beta Subunit/metabolism
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Affiliation(s)
- Kaori Hosokawa
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Yoji Hamada
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, Nagoya, Japan;
| | - Atsushi Fujiya
- Department of Diabetology and Nephrology, Ogaki Municipal Hospital, Ogaki City, Gifu Prefecture, Japan
| | - Masatoshi Murase
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Ryuya Maekawa
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Yasuhiro Niwa
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Takako Izumoto
- Department of Oral and Maxillofacial Surgery, Nagoya University Graduate School of Medicine, Nagoya, Japan; and
| | - Yusuke Seino
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Shin Tsunekawa
- Division of Diabetes, Department of Internal Medicine, Aichi Medical University School of Medicine, Nagakute, Japan
| | - Hiroshi Arima
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, Nagoya, Japan
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Mackesy DZ, Goalstone ML. Extracellular signal-regulated kinase-5: Novel mediator of insulin and tumor necrosis factor α-stimulated vascular cell adhesion molecule-1 expression in vascular cells. J Diabetes 2014; 6:595-602. [PMID: 24460840 DOI: 10.1111/1753-0407.12132] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2013] [Revised: 12/18/2013] [Accepted: 01/21/2014] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND Atherosclerosis may be stimulated by the increased presence of insulin and tumor necrosis-factor-α (TNFα) with subsequent expression of vascular cell adhesion molecule-1 (VCAM-1). We hypothesized that extracellular signal-regulated kinase-5 (ERK5) plays an important role in insulin and TNFα-stimulated total and cell surface VCAM-1 expression. METHODS Rat aorta vascular endothelial cells were first transfected with either no inhibitory RNA, inactive (scrambled) inhibitory ERK5 RNA (scERK5) or active inhibitory ERK5 RNA (siERK5) and then treated with either (i) no analog; (ii) insulin (1 nM), or TNFα (1 ng/mL) alone, or (iii) insulin plus TNFα for 6 h. Thereafter either total VCAM-1 protein or surface VCAM-1 protein was determined. RESULTS Genetic inhibition of ERK5 decreased TNFα-stimulated total VCAM-1 expression by 57% and surface expression by 27%. In contrast, genetic inhibition of ERK5 did not significantly decrease insulin-stimulated total or surface VCAM-1 expression. Interestingly, genetic inhibition of ERK5 did not significantly decrease insulin plus TNFα-stimulated total VCAM-1 expression, but significantly (P < 0.05) decreased insulin plus TNFα-stimulated surface VCAM-1 expression 41%. CONCLUSIONS We report here that ERK5 plays a minor role in insulin-stimulation of VCAM-1, but plays a significant role in TNFα-stimulation of both total and cell surface VCAM-1 protein expression. Taken together, these results demonstrate that not only does ERK5 have differential mediation of insulin and TNFα-stimulated VCAM-1 expression, but also has differential regulation of insulin plus TNFα-stimulated total and surface VCAM-1 expression, suggesting that other intermediates of the insulin and TNFα intracellular pathways are contributing to atherogenesis.
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Affiliation(s)
- Daniel Z Mackesy
- Research Department, Eastern Colorado Health Care System, Denver, Colorado, USA
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Kim SH, Huh CS, Choi ID, Jeong JW, Ku HK, Ra JH, Kim TY, Kim GB, Sim JH, Ahn YT. The anti-diabetic activity of Bifidobacterium lactis HY8101 in vitro and in vivo. J Appl Microbiol 2014; 117:834-45. [PMID: 24925305 DOI: 10.1111/jam.12573] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2014] [Revised: 05/13/2014] [Accepted: 06/08/2014] [Indexed: 01/19/2023]
Abstract
AIMS The aim of this study was to evaluate the effects of Bifidobacterium lactis HY8101 on insulin resistance induced using tumour necrosis factor-α (TNF-α) in rat L6 skeletal muscle cells and on the KK-A(Y) mouse noninsulin-dependent diabetes mellitus (NIDDM) model. METHODS AND RESULTS The treatment using HY8101 improved the insulin-stimulated glucose uptake and translocation of GLUT4 via the insulin signalling pathways AKT and IRS-1(Tyr) in TNF-α-treated L6 cells. HY8101 increased the mRNA levels of GLUT4 and several insulin sensitivity-related genes (PPAR-γ) in TNF-α-treated L6 cells. In KK-A(Y) mice, HY8101 decreased fasting insulin and blood glucose and significantly improved insulin tolerance. HY8101 improved diabetes-induced plasma total cholesterol and triglyceride (TG) levels and increased the muscle glycogen content. We observed concurrent transcriptional changes in the skeletal muscle tissue and the liver. In the skeletal muscle tissue, the glycogen synthesis-related gene pp-1 and GLUT4 were up-regulated in mice receiving HY8101 treatment. In the liver, the hepatic gluconeogenesis-regulated genes (PCK1 and G6PC) were down-regulated in mice receiving HY8101 treatment. CONCLUSIONS Bifidobacterium lactis HY8101 can be used to moderate glucose metabolism, lipid metabolism and insulin sensitivity in mice and in cells. SIGNIFICANCE AND IMPACT OF THE STUDY Bifidobacterium lactis HY8101 might have potential as a probiotic candidate for alleviating metabolic syndromes such as diabetes.
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Affiliation(s)
- S-H Kim
- R&BD Center, Korea Yakult Co. Ltd., Yongin, Korea
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Mackesy DZ, Goalstone ML. Insulin augments tumor necrosis factor-alpha stimulated expression of vascular cell adhesion molecule-1 in vascular endothelial cells. JOURNAL OF INFLAMMATION-LONDON 2011; 8:34. [PMID: 22093181 PMCID: PMC3248376 DOI: 10.1186/1476-9255-8-34] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/01/2011] [Accepted: 11/17/2011] [Indexed: 11/10/2022]
Abstract
BACKGROUND Atherosclerosis is an inflammatory disease that is marked by increased presence of Tumor Necrosis Factor-alpha (TNFα), increased expression of Vascular Cell Adhesion Molecule-1 (VCAM-1), increased presence of serum monocytes and activation of the canonical inflammatory molecule, Nuclear Factor Kappa-B (NFκB). Hyperinsulinemia is a hallmark of insulin resistance and may play a key role in this inflammatory process. METHODS Using Western blot analysis, immunocytochemistry, flow cytometry and biochemical inhibitors, we measured changes in VCAM-1 protein expression and NFκB translocation in vascular endothelial cells in the presence of TNFα and/or hyperinsulinemia and in the absence or presence of kinase pathway inhibitors. RESULTS We report that hyperinsulinemia augmented TNFα stimulated increases in VCAM-1 protein greater than seen with TNFα alone and decreased the time in which VCAM-1 translocated to the cell surface. We also observed that in the presence of Wortmannin, a biochemical inhibitor of phosphatidylinositol 3-kinase (a hallmark of insulin resistance), VCAM-1 expression was greater in the presence of TNFα plus insulin as compared to that seen with insulin or TNFα alone. Additionally, nuclear import of NFκB occurred sooner in the presence of insulin and TNFα together as compared to each alone, and in the presence of Wortmannin, nuclear import of NFκB was greater than that seen with insulin and TNFα alone. CONCLUSIONS hyperinsulinemia and insulin resistance appear to augment the inflammatory effects of TNFα on VCAM-1 expression and NFκB translocation, both of which are markers of inflammation in the vasculature.
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Affiliation(s)
- Daniel Z Mackesy
- Department of Research Service, Eastern Colorado Health Care System, 1055 Clermont Street, Denver, 80220, USA.
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Nohara A, Okada S, Ohshima K, Pessin JE, Mori M. Cyclin-dependent kinase-5 is a key molecule in tumor necrosis factor-α-induced insulin resistance. J Biol Chem 2011; 286:33457-65. [PMID: 21813649 DOI: 10.1074/jbc.m111.231431] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The mechanism of TNF-α-induced insulin resistance has remained unresolved with evidence for down-regulation of insulin effector targets effects or blockade of proximal as well as distal insulin signaling events depending upon the dose, time, and cell type examined. To address this issue we examined the acute actions of TNF-α in differentiated 3T3L1 adipocytes. Acute (5-15 min) treatment with 20 ng/ml (~0.8 nm) TNF-α had no significant effect on IRS1-associated phosphatidylinositol 3-kinase. In contrast, TNF-α increased insulin-stimulated cyclin-dependent kinase-5 (CDK5) phosphorylation on tyrosine residue 15 through an Erk-dependent pathway and up-regulated the expression of the CDK5 regulator protein p35. In parallel, TNF-α stimulation also resulted in the phosphorylation and GTP loading of the Rho family GTP-binding protein, TC10α. TNF-α enhanced the depolymerization of cortical F-actin and inhibited insulin-stimulated glucose transporter-4 (GLUT4) translocation. Treatment with the MEK inhibitor, PD98059, blocked the TNF-α-induced increase in CDK5 phosphorylation and the depolymerization of cortical F-actin. Conversely, siRNA-mediated knockdown of CDK5 or treatment with the MEK inhibitor restored the impaired insulin-stimulated GLUT4 translocation induced by TNF-α. Furthermore, siRNA-mediated knockdown of p44/42 Erk also rescued the TNF-α inhibition of insulin-stimulated GLUT4 translocation. Together, these data demonstrate that TNF-α-mediated insulin resistance of glucose uptake can occur through a MEK/Erk-dependent activation of CDK5.
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Affiliation(s)
- Atsushi Nohara
- Department of Medicine and Molecular Science, Gunma University Graduate School of Medicine, 3-39-15 Showa-machi, Maebashi, Japan
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RAJBHANDARY ROSY, KHEZRI AZADEH, PANUSH RICHARDS. Rheumatoid Cachexia: What Is It and Why Is It Important? J Rheumatol 2011; 38:406-8. [DOI: 10.3899/jrheum.101036] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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7
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Treatment with TNF-alpha and IFN-gamma alters the activation of SER/THR protein kinases and the metabolic response to IGF-I in mouse c2c12 myogenic cells. Cell Mol Biol Lett 2009; 15:13-31. [PMID: 19685010 PMCID: PMC6275934 DOI: 10.2478/s11658-009-0033-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2009] [Accepted: 08/06/2009] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED The aim of this study was to compare the effects of TNF-alpha, IL-1beta and IFN-gamma on the activation of protein kinase B (PKB), p70(S6k), mitogen-activated protein kinase (MAPK) and p90( rsk ), and on IGF-I-stimulated glucose uptake and protein synthesis in mouse C2C12 myotubes. 100 nmol/l IGF-I stimulated glucose uptake in C2C12 myotubes by 198.1% and 10 ng/ml TNF-alpha abolished this effect. Glucose uptake in cells differentiated in the presence of 10 ng/ml IFN-gamma increased by 167.2% but did not undergo significant further modification upon the addition of IGF-I. IGF-I increased the rate of protein synthesis by 249.8%. Neither TNF-alpha nor IFN-gamma influenced basal protein synthesis, but both cytokines prevented the IGF-I effect. 10 ng/ml IL-1beta did not modify either the basal or IGF-I-dependent glucose uptake and protein synthesis. With the exception of TNF-alpha causing an 18% decrease in the level of PKB protein, the cellular levels of PKB, p70(S6k), p42(MAPK), p44(MAPK) and p90( rsk ) were not affected by the cytokines. IGF-I caused the phosphorylation of PKB (an approximate 8-fold increase above the basal value after 40 min of IGF-I treatment), p42(MAPK) (a 2.81-fold increase after 50 min), and the activation of p70(S6k) and p90( rsk ), manifesting as gel mobility retardation. In cells differentiated in the presence of TNF-alpha or IFN-gamma, this IGF-I-mediated PKB and p70(S6k) phosphorylation was significantly diminished, and the increase in p42(MAPK) and p90( rsk ) phosphorylation was prevented. The basal p42(MAPK) phosphorylation in C2C12 cells treated with IFN-gamma was high and comparable with the activation of this kinase by IGF-I. Pretreatment of myogenic cells with IL-1beta did not modify the IGF-I-stimulated phosphorylation of PKB, p70(S6k), p42(MAPK) and p90( rsk ). IN CONCLUSION i) TNF-alpha and IFN-gamma, but not IL-1beta, if present in the extracellular environment during C2C12 myoblast differentiation, prevent the stimulatory action of IGF-I on protein synthesis. ii) TNF-alpha- and IFN-gamma-induced IGF-I resistance of protein synthesis could be associated with the decreased phosphorylation of PKB and p70(S6k). iii) The activation of glucose uptake in C2C12 myogenic cells treated with IFN-gamma is PKB independent. iv) The similar effects of TNF-alpha and IFN-gamma on the signalling and action of IGF-I on protein synthesis in myogenic cells could suggest the involvement of both of these cytokines in protein loss in skeletal muscle.
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Abstract
Insulin resistance and hyperinsulinemia are common findings in patients with essential hypertension. Recent evidence indicates that these impairments in glucose metabolism may play a role not only in the development of type 2 diabetes, but also in the onset and persistence of hypertension, dyslipidemia, and abdominal obesity. The accumulation of these risk factors constitutes a high-risk group of cardiovascular diseases, the so-called metabolic syndrome. Insulin resistance has also been reported in several animal models for hypertension, including the spontaneously hypertensive rat (SHR) and the fructose-fed rat (FFR). SHRs and FFRs have been employed in many studies to investigate the mechanisms and pathophysiology of insulin resistance and hypertension, but the precise mechanism of insulin resistance remains to be clarified. In this review, the possible mechanisms of insulin resistance in SHRs and FFRs are summarized.
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Affiliation(s)
- Kazuaki Shimamoto
- The Second Department of Internal Medicine, Sapporo Medical University School of Medicine, Sapporo, Japan
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9
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Iwasaki Y, Nishiyama M, Taguchi T, Asai M, Yoshida M, Kambayashi M, Terada Y, Hashimoto K. Insulin exhibits short-term anti-inflammatory but long-term proinflammatory effects in vitro. Mol Cell Endocrinol 2009; 298:25-32. [PMID: 18955107 DOI: 10.1016/j.mce.2008.09.030] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2008] [Revised: 09/12/2008] [Accepted: 09/18/2008] [Indexed: 01/04/2023]
Abstract
Although insulin is indispensable for maintaining glucose homeostasis, it is still controversial whether or not a high concentration of insulin is deleterious. We examined the effect of insulin on the transcriptional activity of NF-kappaB, which mediates the expression of a variety of inflammation/coagulation-related genes using hepatocyte cell lines in vitro. We found that insulin (1 nM) alone caused minimal increase in NF-kappaB-mediated transcription. On the other hand, when cells were simultaneously treated with proinflammatory cytokines such as TNFalpha, the following dual effect of insulin was observed: short-term (6h) suppressive, and long-term (36 h or later) stimulatory effects. The former effect was transient and appears to be mediated by the phosphatidylinositol 3 kinase (PI(3)K) signaling pathway. The latter effect, in contrast, was more pronounced, enhancing the TNFalpha-stimulated NF-kappaB-dependent transcription by more than sevenfold. This positive effect was NF-kappaB-specific, and was eliminated by mitogen-activated protein kinase (MAPK) inhibitors. Altogether, our data suggest that insulin has short-term anti-inflammatory but long-term proinflammatory effects. From a clinical standpoint, this implies that low basal and periodically high plasma insulin is beneficial, whereas a sustained rise in plasma insulin, as often seen in patients with obesity, may induce atherothrombotic disorders, because of the NF-kappaB-mediated overexpression of proinflammatory/procoagulant/antifibrinolytic proteins in the liver.
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Affiliation(s)
- Yasumasa Iwasaki
- Department of Endocrinology, Metabolism, and Nephrology, Kochi Medical School, Kochi University, Nankoku 783-8505, Japan.
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Samokhvalov V, Bilan PJ, Schertzer JD, Antonescu CN, Klip A. Palmitate- and lipopolysaccharide-activated macrophages evoke contrasting insulin responses in muscle cells. Am J Physiol Endocrinol Metab 2009; 296:E37-46. [PMID: 18840759 DOI: 10.1152/ajpendo.90667.2008] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Factors secreted by macrophages contribute to whole body insulin resistance, acting in part on adipose tissue. Muscle is the major tissue for glucose disposal, but how macrophage-derived factors impact skeletal muscle glucose uptake is unknown, or whether the macrophage environment influences this response. We hypothesized that conditioned medium from macrophages pretreated with palmitate or LPS would directly affect insulin action and glucose uptake in muscle cells. L6-GLUT4myc myoblasts were exposed to conditioned medium from RAW 264.7 macrophages pretreated with palmitate or LPS. Conditioned medium from palmitate-treated RAW 264.7 macrophages inhibited myoblast insulin-stimulated glucose uptake, GLUT4 translocation, and Akt phosphorylation while activating JNK p38 MAPK, decreasing IkappaBalpha, and elevating inflammation markers. Surprisingly, and opposite to its effects on adipose cells, conditioned medium from LPS-treated macrophages stimulated myoblast insulin-stimulated glucose uptake, GLUT4 translocation, and Akt phosphorylation without affecting stress kinases or inflammation indexes. This medium had markedly elevated IL-10 levels, and IL-10, alone, potentiated insulin action in myoblasts and partly reversed the insulin resistance imparted by medium from palmitate-treated macrophages. IL-10 neutralizing antibodies blunted the positive influence of LPS macrophage-conditioned medium. We conclude that myoblasts and adipocytes respond differently to cytokines. Furthermore, depending on their environment, macrophages negatively or positively influence muscle cells. Macrophages exposed to palmitate produce a mixture of proinflammatory cytokines that reduce insulin action in muscle cells; conversely, LPS-activated macrophages increase insulin action, likely via IL-10. Macrophages may be an integral element in glucose homeostasis in vivo, relaying effects of circulating factors to skeletal muscle.
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Affiliation(s)
- Victor Samokhvalov
- Cell Biology Program, The Hospital for Sick Children, 555 University Ave., Toronto, ON, M5G 1X8 Canada
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Okazaki M, Iwasaki Y, Jing H, Nishiyama M, Taguchi T, Tsugita M, Taniguchi Y, Kambayashi M, Hashimoto K. Insulin enhancement of cytokine-induced coagulation/inflammation-related gene transcription in hepatocytes. Endocr J 2008; 55:967-75. [PMID: 18614853 DOI: 10.1507/endocrj.k08e-078] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Hyperinsulinemia is a known risk factor for cardiovascular events, but its molecular basis is not completely understood. In this study, we examined the effects of insulin alone, or insulin and proinflammatory cytokines, on the expression of inflammation/coagulation-related genes in hepatocytes. We found that, in the HepG2 human hepatocyte cell line, insulin stimulated the transcriptional activity of plasminogen activator inhibitor 1 (PAI-1), fibrinogen-gamma and C-reactive protein (CRP) genes in time- and dose-dependent manners. These effects were completely inhibited by MAP kinase inhibitor PD98059, but not by PI3 kinase inhibitor wortmannin. As previously reported, proinflammatory cytokines like interleukin 1beta and interleukin 6 showed stimulatory effects on the expression of these genes, and we now found that the combination of insulin and the cytokines showed more than additive effects in most cases. Interleukin 1beta and insulin also cooperatively increased the endogenous mRNA level of PAI-1. These results suggest that the coexistence of high insulin and cytokines may induce inflammation and hypercoagulation in a synergistic manner. This may partly explain why the accumulation of multiple risk factors, especially hyperinsulinemia caused by insulin resistance and enhanced production of proinflammatory cytokines, results in inflammation, thrombosis, and cardiovascular events in metabolic syndrome.
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Affiliation(s)
- Mizuho Okazaki
- Department of Endocrinology, Metabolism, and Nephrology, Kochi Medical School, Kochi University, Oko-cho, Nankoku, Japan
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Hafer-Macko CE, Ryan AS, Ivey FM, Macko RF. Skeletal muscle changes after hemiparetic stroke and potential beneficial effects of exercise intervention strategies. JOURNAL OF REHABILITATION RESEARCH AND DEVELOPMENT 2008; 45:261-72. [PMID: 18566944 PMCID: PMC2978978 DOI: 10.1682/jrrd.2007.02.0040] [Citation(s) in RCA: 134] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Stroke is the leading cause of disability in the United States. New evidence reveals significant structural and metabolic changes in skeletal muscle after stroke. Muscle alterations include gross atrophy and shift to fast myosin heavy chain in the hemiparetic (contralateral) leg muscle; both are related to gait deficit severity. The underlying molecular mechanisms of this atrophy and muscle phenotype shift are not known. Inflammatory markers are also present in contralateral leg muscle after stroke. Individuals with stroke have a high prevalence of insulin resistance and diabetes. Skeletal muscle is a major site for insulin-glucose metabolism. Increasing evidence suggests that inflammatory pathway activation and oxidative injury could lead to wasting, altered function, and impaired insulin action in skeletal muscle. The health benefits of exercise in disabled populations have now been recognized. Aerobic exercise improves fitness, strength, and ambulatory performance in subjects with chronic stroke. Therapeutic exercise may modify or reverse skeletal muscle abnormalities.
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Angiotensin II inhibits glucose uptake of skeletal muscle via the adenosine monophosphate-activated protein kinase pathway. ACTA ACUST UNITED AC 2007; 1:251-5. [DOI: 10.1016/j.jash.2007.04.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2007] [Revised: 04/05/2007] [Accepted: 04/25/2007] [Indexed: 11/23/2022]
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Sharma G, Goalstone ML. Regulation of ERK5 by insulin and angiotensin-II in vascular smooth muscle cells. Biochem Biophys Res Commun 2007; 354:1078-83. [PMID: 17275785 PMCID: PMC1850970 DOI: 10.1016/j.bbrc.2007.01.102] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2007] [Accepted: 01/22/2007] [Indexed: 11/23/2022]
Abstract
ERK5 is involved in proliferation of vascular smooth muscle cells (VSMC). The proliferative actions of insulin and angiotensin-II (A-II) in VSMC are mediated in part by ERK1/2. We hypothesized that insulin and A-II also regulate ERK5 activity in VSMC. Acute treatment (<60min) with insulin or A-II increased phosphorylation of ERK1/2 at 15min and ERK5 at 5min. Chronic treatment (< or = 8h) with insulin increased ERK1/2 phosphorylation by 4h and ERK5 by 8h. A-II-stimulated phosphorylation of ERK1/2 by 8h and ERK5 by 4h. The EC(50) for insulin treatment effecting ERK1/2 and ERK5 phosphorylation was 1.5 and 0.1nM, whereas the EC(50) for A-II was 2nM, each. Insulin plus A-II induced an additive effect only on ERK5 phosphorylation. Inhibition of insulin- and A-II-stimulated phosphorylation of ERK5 and ERK1/2 by PD98059 and Wortmannin exhibited differential and time-dependent effects. Taken together, these data indicate that insulin and A-II regulate the activity of ERK5, but different from that seen for ERK1/2.
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Affiliation(s)
- Girish Sharma
- University of Colorado at Denver and Health Sciences Center, Aurora, CO 80220, USA
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15
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Johansson GS, Arnqvist HJ. Insulin and IGF-I action on insulin receptors, IGF-I receptors, and hybrid insulin/IGF-I receptors in vascular smooth muscle cells. Am J Physiol Endocrinol Metab 2006; 291:E1124-30. [PMID: 16803852 DOI: 10.1152/ajpendo.00565.2005] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Insulin and insulin-like growth factor I (IGF-I) are known to affect cardiovascular disease. We have investigated ligand binding and the dose-response relationship for insulin and IGF-I on vascular smooth muscle cells (VSMCs) at the receptor level. VSMCs from rat thoracic aorta were serum starved, stimulated with IGF-I or insulin, lysed, immunoprecipitated, and analyzed by Western blot. d-[U-(14)C]Glucose accumulation and [6-(3)H]thymidine incorporation into DNA were also measured. Specific binding of both insulin and IGF-I was demonstrated, being higher for IGF-I. Both IGF-I receptor (IGF-IR) and insulin receptor (IR) beta-subunits were detected and coprecipitated after immunoprecipitation (IP) against either of the two. No coprecipitation was found after reduction of disulphide bonds with dithiotreitol before IP. After stimulation with 10(-10)-10(-9) M IGF-I, IP of the IGF-IR, or IR beta-subunit and immunoblot with anti-phosphotyrosine antibody, we found two distinct bands indicating phosphorylation of both the IGF-IR and the IR beta-subunit. Stimulation with 10(-10)-10(-9) M insulin and IP against the IGF-IR did not show phosphorylation of either beta-subunit, whereas after IP of the IR we found phosphorylation of the IR beta-subunit. [(14)C]Glucose accumulation and [(3)H]thymidine incorporation were elevated in cells stimulated with IGF-I at 10(-10)-10(-7) M, reaching maximum by 10(-9) M. Insulin stimulation showed measurable effects only at supraphysiological concentrations, 10(-8)-10(-7) M. In conclusion, coprecipitation of both the IGF-IR and the IR beta-subunit indicates the presence of hybrid insulin/IGF-I receptors in VSMC. At a physiological concentration, insulin activates the IR but does not affect either glucose metabolism or DNA synthesis, whereas IGF-I both activates the receptor and elicits biological effect.
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MESH Headings
- Animals
- Aorta, Thoracic/cytology
- Carbon Radioisotopes
- Cells, Cultured
- Dimerization
- Glucose/pharmacokinetics
- Hypoglycemic Agents/metabolism
- Hypoglycemic Agents/pharmacology
- Insulin/metabolism
- Insulin/pharmacology
- Insulin-Like Growth Factor I/metabolism
- Insulin-Like Growth Factor I/pharmacology
- Iodine Radioisotopes
- Ligands
- Male
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/metabolism
- Phosphorylation
- Rats
- Rats, Sprague-Dawley
- Receptor, IGF Type 1/chemistry
- Receptor, IGF Type 1/metabolism
- Receptor, Insulin/chemistry
- Receptor, Insulin/metabolism
- Thymidine/pharmacokinetics
- Tritium
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Affiliation(s)
- Git S Johansson
- Department of Biomedicine and Surgery, Division of Cell Biology, Linköping University, Linköping, Sweden.
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Yamaguchi K, Ura N, Murakami H, Togashi N, Hyakukoku M, Higashiura K, Shimamoto K. Olmesartan ameliorates insulin sensitivity by modulating tumor necrosis factor-alpha and cyclic AMP in skeletal muscle. Hypertens Res 2006; 28:773-8. [PMID: 16419651 DOI: 10.1291/hypres.28.773] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
We have reported that tumor necrosis factor (TNF)-alpha in skeletal muscle is one of the determinants of insulin resistance and that the renin-angiotensin system may be related to the regulation of TNF-a in skeletal muscle. Recent studies have suggested the involvement of cyclic adenosine monophosphate (cAMP) in the regulation of TNF-a in vascular smooth muscle cells or monocytes. The aim of this study was to determine the relationship between cAMP and TNF-a in skeletal muscle in connection with the renin-angiotensin system. Six-week-old male Sprague-Dawley rats were fed either normal rat chow or fructose-rich chow for 6 weeks. For the last 2 weeks of a 6-week period, the rats were treated with a vehicle or with an angiotensin II type 1 receptor antagonist (olmesartan medoxomil, 0.1 mg/kg/day). TNF-alpha levels in the soleus muscle were significantly higher and cAMP levels in the soleus muscle were significantly lower in fructose-fed rats than in control rats. Olmesartan increased cAMP and reduced TNF-a simultaneously in fructose-fed rats. There was a significant negative correlation between levels of cAMP and TNF-alpha. Moreover, a cAMP analogue reduced TNF-a levels in the soleus muscle. These results indicate that the increase in TNF-alpha via suppression of cAMP may affect the induction of insulin resistance. In addition, the facts that olmesartan increased cAMP and decreased TNF-alpha suggest that a part of the TNF-alpha regulation by angiotensin II might consist of modulation of cAMP through Gi protein activation in skeletal muscle.
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Affiliation(s)
- Koichi Yamaguchi
- Second Department of Internal Medicine, Sapporo Medical University School of Medicine, Sapporo, Japan
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Tanaka Y, Kikuchi T, Nagasaki K, Hiura M, Ogawa Y, Uchiyama M. Lower Birth Weight and Visceral Fat Accumulation Are Related to Hyperinsulinemia and Insulin Resistance in Obese Japanese Children. Hypertens Res 2005; 28:529-36. [PMID: 16231759 DOI: 10.1291/hypres.28.529] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
This study aimed to reveal the relation of birth weight (or the birth weight standard deviation score [BWSDS]) and visceral fat accumulation to hyperinsulinemia and insulin resistance. We examined obese Japanese children (650 boys and 317 girls) with a mean age of 10.3 years (range, 6-15 years). The mean percentage of overweight to the standard body weight of Japanese children was 52.1% in boys and 51.4% in girls. Abdominal fat thickness (maximum preperitoneal fat thickness; Pmax) was measured using ultrasonography. The fasting serum insulin and plasma glucose levels were measured, and the homeostasis model assessment-insulin resistance (HOMA-R) and quantitative insulin sensitivity check index (QUICKI) were calculated. We divided the subjects into four groups according to their birth weight or BWSDS, and compared anthropometric measurements, Pmax, blood pressure, serum insulin levels, HOMA-R and QUICKI among the quartiles. The relationships of both birth weight (or BWSDS) and Pmax to serum insulin levels (or HOMA-R, QUICKI) were examined with multiple regression analyses. The fasting serum insulin level and HOMA-R were highest in the quartile with the lowest birth weight or BWSDS. The birth weight and BWSDS were inversely related to the serum insulin levels and HOMA-R, positively related to QUICKI, and independent of Pmax. Our findings suggest that both lower birth weight and visceral fat accumulation may be independently related to hyperinsulinemia and insulin resistance in obese Japanese children.
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Affiliation(s)
- Yukie Tanaka
- Division of Pediatrics, Department of Homeostatic Regulation and Development, Niigata University Graduate School of Medicine and Dental Sciences, Niigata, Japan.
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