Dataset Information

Palmitate increases sphingosine-1-phosphate in C2C12 myotubes via upregulation of sphingosine kinase message and activity.

ABSTRACT: Studies in skeletal muscle demonstrate that elevation of plasma FFAs increases the sphingolipid ceramide. We aimed to determine the impact of FFA oversupply on total sphingolipid profiles in a skeletal muscle model. C2C12 myotubes were treated with palmitate (PAL). Lipidomics analysis revealed pleiotropic effects of PAL on cell sphingolipids not limited to ceramides. (13)C labeling demonstrated that PAL activated several branches of sphingolipid synthesis by distinct mechanisms. Intriguingly, PAL increased sphingosine-1-phosphate independently of de novo synthesis. Quantitative real-time PCR demonstrated that PAL increased sphingosine kinase 1 (SK1) mRNA by approximately 4-fold. This was accompanied by a 2.3-fold increase in sphingosine kinase enzyme activity. This upregulation did not occur upon treatment with oleate, suggesting some level of specificity for PAL. These findings were recapitulated in the diet-induced obesity mouse model, in which high-fat feeding increased SK1 message in skeletal muscle over 2.3-fold. These data suggest that the impact of elevated FFA on sphingolipids reaches beyond ceramides and de novo sphingolipid synthesis. Moreover, these findings identify PAL as a novel regulatory stimulus for SK1.

SUBMITTER: Hu W

PROVIDER: S-EPMC2724779 | biostudies-literature | 2009 Sep

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Palmitate increases sphingosine-1-phosphate in C2C12 myotubes via upregulation of sphingosine kinase message and activity.

Hu Wei W Bielawski Jacek J Samad Fahumiya F Merrill Alfred H AH Cowart L Ashley LA

Journal of lipid research 20090415 9

Studies in skeletal muscle demonstrate that elevation of plasma FFAs increases the sphingolipid ceramide. We aimed to determine the impact of FFA oversupply on total sphingolipid profiles in a skeletal muscle model. C2C12 myotubes were treated with palmitate (PAL). Lipidomics analysis revealed pleiotropic effects of PAL on cell sphingolipids not limited to ceramides. (13)C labeling demonstrated that PAL activated several branches of sphingolipid synthesis by distinct mechanisms. Intriguingly, PA ...[more]

PMID: 19369694

Similar Datasets

Project description:Sphingosine-1-phosphate (SPP) is a bioactive lipid that has recently been identified as the ligand for the EDG family of G protein-coupled cell surface receptors. However, the mitogenic and survival effects of exogenous SPP may not correlate with binding to cell-surface receptors (Van Brocklyn, J.R., M.J. Lee, R. Menzeleev, A. Olivera, L. Edsall, O. Cuvillier, D.M. Thomas, P.J.P. Coopman, S. Thangada, T. Hla, and S. Spiegel. 1998. J. Cell Biol. 142:229-240). The recent cloning of sphingosine kinase, a unique lipid kinase responsible for the formation of SPP, has provided a new tool to investigate the role of intracellular SPP. Expression of sphingosine kinase markedly increased SPP levels in NIH 3T3 fibroblasts and HEK293 cells, but no detectable secretion of SPP into the medium was observed. The increased sphingosine kinase activity in NIH 3T3 fibroblasts was sufficient to promote growth in low- serum media, expedite the G(1)/S transition, and increase DNA synthesis and the proportion of cells in the S phase of the cell cycle with a concomitant increase in cell numbers. Transient or stable overexpression of sphingosine kinase in NIH 3T3 fibroblasts or HEK293 cells protected against apoptosis induced by serum deprivation or ceramide elevation. N,N-Dimethylsphingosine, a competitive inhibitor of sphingosine kinase, blocked the effects of sphingosine kinase overexpression on cell proliferation and suppression of apoptosis. In contrast, pertussis toxin did not abrogate these biological responses. In Jurkat T cells, overexpression of sphingosine kinase also suppressed serum deprivation- and ceramide-induced apoptosis and, to a lesser extent, Fas-induced apoptosis, which correlated with inhibition of DEVDase activity, as well as inhibition of the executionary caspase-3. Taken together with ample evidence showing that growth and survival factors activate sphingosine kinase, our results indicate that SPP functions as a second messenger important for growth and survival of cells. Hence, SPP belongs to a novel class of lipid mediators that can function inside and outside cells.

Dataset Information

Palmitate increases sphingosine-1-phosphate in C2C12 myotubes via upregulation of sphingosine kinase message and activity.

Publications

Palmitate increases sphingosine-1-phosphate in C2C12 myotubes via upregulation of sphingosine kinase message and activity.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets