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Hoffmann, R. A wiki for the life sciences where authorship matters. Nature Genetics (2008)
 
 
 

Inhibitory effects of TNF alpha on mouse tumor Leydig cells: possible role of ceramide in the mechanism of action.

TNF alpha is reported to inhibit steroidogenesis in mouse Leydig cells. In primary cells this inhibition resulted mainly from a reduced expression of Cyp-17 gene. Mouse tumor Leydig cells, MA-10, being free of macrophages and lacking Cyp-17, appear to be an excellent model to investigate those effects of TNF alpha which are independent of either macrophages or Cyp-17. We report here that TNF alpha receptors are expressed in this cell line. Treatment of the cells with TNF alpha had no effect on basal progesterone production. In contrast, LH-, 8Br-cAMP and forskolin-stimulated progesterone production was inhibited by TNF alpha. Neither enzymes involved in the conversion of cholesterol to pregnenolone nor hormone- induced hydrolysis of [14C] cholesterol-ester were affected by TNF alpha. The hormone-induced expression of StAR protein was diminished in mitochondrial fractions from TNF alpha-treated cells. Also cell permeable ceramides markedly inhibited StAR protein levels. We show further that TNF alpha was able to induce [14C]-ceramide accumulation in MA-10 cells and suggest that this sphingolipid may be considered as a transmitter of TNF alpha signals to the StAR protein.[1]

References

  1. Inhibitory effects of TNF alpha on mouse tumor Leydig cells: possible role of ceramide in the mechanism of action. Budnik, L.T., Jähner, D., Mukhopadhyay, A.K. Mol. Cell. Endocrinol. (1999) [Pubmed]
 
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