[en] Toll-like receptors 2 (TLR2) and 4 (TLR4) are present in the plasma membrane of skeletal muscle cells where their functions remain incompletely resolved. They can bind various extracellular ligands, such as FSL-1, lipopolysaccharide (LPS) and/or palmitic acid (PA). We have investigated the link between PA, TLR2/4 and ribosomal S6 kinase 1 (S6K1) in C2C12 myotubes. Incubation with agonists of either TLR2 or TLR4, and with a high concentration of PA, increased S6K1 phosphorylation. Canonical upstream kinases of S6K1, protein kinase B (PKB) and mammalian target of rapamycin complex 1 (mTORC1), were regulated in the opposite way by PA, indicating that these kinases were probably not involved. By using the SB202190 inhibitor, p38 MAPK (mitogen-activated protein kinase) was found to be a key mediator of PA-induced phosphorylation of S6K1. Downregulation of either tlr2 or tlr4 gene expression by small interfering RNAs prevented the activation of both p38 MAPK and S6K1 by FSL-1, LPS or PA. Thus TLR2 and TLR4 agonists can increase the level of S6K1 phosphorylation in a p38 MAPK-dependent way in C2C12 myotubes. As PA induced the same intracellular signalling, a novel atypical pathway for PA is induced at the cellular membrane level and results in a higher phosphorylation state of S6K1.
Disciplines :
Biochemistry, biophysics & molecular biology
Author, co-author :
Zbinden-Foncea, Hermann
Deldicque, Louise
Pierre, Nicolas ; Université de Liège - ULiège > Département des sciences cliniques > Hépato-gastroentérologie
Francaux, Marc
Raymackers, Jean-Marc
Language :
English
Title :
TLR2 and TLR4 activation induces p38 MAPK-dependent phosphorylation of S6 kinase 1 in C2C12 myotubes.
Publication date :
2012
Journal title :
Cell Biology International
ISSN :
1065-6995
eISSN :
1095-8355
Publisher :
Wiley-Blackwell, New York, United States - New York
Aas V, Rokling-Andersen M, Wensaas AJ, Thoresen GH, Kase ET, Rustan AC. Lipid metabolism in human skeletal muscle cells: effects of palmitate and chronic hyperglycaemia. Acta Physiol Scand 2005;183:31-41.
Akira S, Yamamoto M, Takeda K. Role of adapters in Toll-like receptor signalling. Biochem Soc Trans 2003;31:637-42.
Baar K, Esser K. Phosphorylation of p70(S6k) correlates with increased skeletal muscle mass following resistance exercise. Am J Physiol. 1999;276:C120-7.
Boden G. Effects of free fatty acids (FFA) on glucose metabolism: significance for insulin resistance and type 2 diabetes. Exp Clin Endocrinol Diabetes 2003;111:121-4.
Caricilli AM,Nascimento PH, Pauli JR, Tsukumo DM, Velloso LA, Carvalheira JB et al. Inhibition of toll-like receptor 2 expression improves insulin sensitivity and signaling in muscle and white adipose tissue of mice fed a high-fat diet. J Endocrinol 2008;199:399-406.
Chavez JA, Summers SA. Characterizing the effects of saturated fatty acids on insulin signaling and ceramide and diacylglycerol accumulation in 3T3-L1 adipocytes and C2C12 myotubes. Arch Biochem Biophys 2003;419:101-9.
Clarke SD. The multi-dimensional regulation of gene expression by fatty acids: polyunsaturated fats as nutrient sensors. Curr Opin Lipidol 2004;15:13-8.
Cuenda A, Cohen P. Stress-activated protein kinase-2/p38 and a rapamycin-sensitive pathway are required for C2C12 myogenesis. J Biol Chem 1999;274:4341-6.
Deldicque L, Atherton P, Patel R, Theisen D, Nielens H, Rennie MJ et al. Decrease in Akt/PKB signalling in human skeletal muscle by resistance exercise. Eur J Appl Physiol 2008;104:57-65.
Deldicque L, Theisen D, Bertrand L, Hespel P, Hue L, Francaux M. Creatine enhances differentiation of myogenic C2C12 cells by activating both p38 and Akt/PKB pathways. Am J Physiol Cell Physiol 2007;293:C1263-71.
Dimopoulos N, Watson M, Sakamoto K, Hundal HS. Differential effects of palmitate and palmitoleate on insulin action and glucose utilization in rat L6 skeletal muscle cells. Biochem J 2006;399:473-81.
Erridge C, Samani NJ. Saturated fatty acids do not directly stimulate Toll-like receptor signaling. Arterioscler Thromb Vasc Biol 2009;29:1944-9.
Esser J, Gehrmann U, Salvado MD, Wetterholm A, Haeggstrom JZ, Samuelsson B et al. Zymosan suppresses leukotriene C synthase activity in differentiating monocytes: antagonism by aspirin and protein kinase inhibitors. FASEB J 2011;25:1417-27.
Fenton TR, Gout IT. Functions and regulation of the 70 kDa ribosomal S6 kinases. Int J Biochem Cell Biol 2011;43:47-59.
Frost RA, Nystrom GJ, Lang CH. Multiple Toll-like receptor ligands induce an IL-6 transcriptional response in skeletal myocytes. Am J Physiol 2006;290:R773-84.
Koopman R, Zorenc AH, Gransier RJ, Cameron-Smith D, van Loon LJ. Increase in S6K1 phosphorylation in human skeletal muscle following resistance exercise occurs mainly in type II muscle fibers. Am J Physiol Endocrinol Metab 2006;290:E1245-52.
Laflamme N, Echchannaoui H, Landmann R, Rivest S. Cooperation between toll-like receptor 2 and 4 in the brain of mice challenged with cell wall components derived from gram-negative and grampositive bacteria. Eur J Imunnol 2003;33:1127-38.
Lambert CP, Wright NR, Finck BN, Villareal DT. Exercise but not dietinduced weight loss decreases skeletal muscle inflammatory gene expression in frail obese elderly persons. J Appl Physiol 2008;105:473-8.
Madan M, Amar S. Toll-like receptor-2 mediates diet and/or pathogen associated atherosclerosis: proteomic findings. PLoS ONE 2008;3:e3204.
Nader GA, McLoughlin TJ, Esser KA. mTOR function in skeletal muscle hypertrophy: increased ribosomal RNA via cell cycle regulators. Am J Physiol Cell Physiol 2005;289:C1457-65.
Pullen N, Thomas G. The modular phosphorylation and activation of p70s6k. FEBS Lett 1997;410:78-82.
Radin MS, Sinha S, Bhatt BA, Dedousis N, O'Doherty RM. Inhibition or deletion of the lipopolysaccharide receptor Toll-like receptor-4 confers partial protection against lipid-induced insulin resistance in rodent skeletal muscle. Diabetologia 2008;51:336-46.
Ragheb R, Shanab GM, Medhat AM, Seoudi DM, Adeli K, Fantus IG. Free fatty acid-induced muscle insulin resistance and glucose uptake dysfunction: evidence for PKC activation and oxidative stress-activated signaling pathways. Biochem Biophys Res Commun 2009;389:211-6.
Reyna SM, Ghosh S, Tantiwong P, Meka CS, Eagan P, Jenkinson CP et al. Elevated toll-like receptor 4 expression and signaling in muscle from insulin-resistant subjects. Diabetes 2008;57:2595-602.
Schmitz-Peiffer C, Craig DL, Biden TJ. Ceramide generation is sufficient to account for the inhibition of the insulin-stimulated PKB pathway in C2C12 skeletal muscle cells pretreated with palmitate. J Biol Chem 1999;274:24202-10.
Senn JJ. Toll-like receptor-2 is essential for the development of palmitate-induced insulin resistance in myotubes. J Biol Chem 2006;281:26865-75.
Shi H, Kokoeva MV, Inouye K, Tzameli I, Yin H, Flier JS. TLR4 links innate immunity and fatty acid-induced insulin resistance. J Clin Invest 2006;116:3015-25.
Terzis G, Georgiadis G, Stratakos G, Vogiatzis I, Kavouras S, Manta P et al. Resistance exercise-induced increase in muscle mass correlates with p70S6 kinase phosphorylation in human subjects. Eur J Appl Physiol 2008;102:145-52.
Tremblay F,Marette A. Amino acid and insulin signaling via themTOR/p70 S6 kinase pathway. A negative feedback mechanism leading to insulin resistance in skeletal muscle cells. J Biol Chem 2001;276:38052-60.
van Loon LJ, Thomason-Hughes M, Constantin-Teodosiu D, Koopman R, Greenhaff PL, Hardie DG et al. Inhibition of adipose tissue lipolysis increases intramuscular lipid and glycogen use in vivo in humans. Am J Physiol Endocrinol Metab 2005;289:E482-93.
Varma V, Yao-Borengasser A, Rasouli N, Nolen GT, Phanavanh B, Starks T et al. Muscle inflammatory response and insulin resistance: synergistic interaction between macrophages and fatty acids leads to impaired insulin action. Am J Physiol Endocrinol Metab 2009;296:E1300-10.
Wang X, Yu W, Nawaz A, Guan F, Sun S, Wang C. Palmitate induced insulin resistance by PKCtheta-dependent activation of mTOR/S6K pathway in C2C12 myotubes. Exp Clin Endocrinol Diabetes 2010;118:657-61.
West AP, Koblansky AA, Ghosh S. Recognition and signaling by toll-like receptors. Annu Rev Cell Dev Biol 2006;22:409-37.