期刊
CELL DEATH & DISEASE
卷 4, 期 -, 页码 -出版社
NATURE PUBLISHING GROUP
DOI: 10.1038/cddis.2013.451
关键词
ceramide; sphingolipids; apoptosis; fulminant hepatic failure; clathrin
类别
资金
- Israel Science Foundation [0888/11]
- Deutsche Forschungsgemeinschaft (DFG) Priority Program 877 [B1]
The involvement of ceramide in death receptor-mediated apoptosis has been widely examined with most studies focusing on the role of ceramide generated from sphingomyelin hydrolysis. We now analyze the effect of the ceramide acyl chain length by studying tumor necrosis factor alpha receptor-1 (TNFR1)-mediated apoptosis in a ceramide synthase 2 (CerS2) null mouse, which cannot synthesize very-long acyl chain ceramides. CerS2 null mice were resistant to lipopolysaccharide/galactosamine-mediated fulminant hepatic failure even though TNF alpha secretion from macrophages was unaffected. Cultured hepatocytes were also insensitive to TNF alpha-mediated apoptosis. In addition, in both liver and in hepatocytes, caspase activities were not elevated, consistent with inhibition of TNFR1 pro-apoptotic signaling. In contrast, Fas receptor activation resulted in the death of CerS2 null mice. Caspase activation was blocked because of the inability of CerS2 null mice to internalize the TNFR1; whereas Fc-TNF alpha was internalized to a perinuclear region in hepatocytes from wild-type mice, no internalization was detected in CerS2 null mice. Our results indicate that altering the acyl chain composition of sphingolipids inhibits TNFR1 internalization and inhibits selective pro-apoptotic downstream signaling for apoptosis.
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