Prenatal alcohol exposure increases TNFα-induced cytotoxicity in primary astrocytes

We examined the effect of prenatal alcohol exposure (PAE) on tumor necrosis factor-α-(TNFα) induced cell death in primary astrocyte cultures. Flow cytometry revealed that PAE increased the sensitivity of astrocytes to the cytotoxic effects of TNFα when compared to astrocytes prepared from pair-fed and chow-fed controls. In a number of cell types, TNFα regulates cell growth or death, in part, by the hydrolysis of sphingomyelin to ceramide and sphingosine-1-phosphate (SPP). Using a 3-(4.5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) cytotoxic assay we found that PAE increased the sensitivity of astrocytes to the cytotoxic effects of TNFα, sphingomyelinase (SMase), and C 2- and C 6-ceramide. The increasing cellular concentrations of SPP, a sphingolipid metabolic that induces cell growth, protected the cells from TNFα-induced cell death. N, N-dimethylsphingosine (DMS), which inhibits SPP production, and N-oleoylethanolamine, which inhibits acid ceramidases, increased TNFα-induced cytotoxicity in astrocytes prepared from PAE rats. These studies suggest that PAE shifts the balance of sphingolipid metabolism in favor of a pathway that increases the susceptibility of astrocytes to the cytotoxic effect of TNFα.