Staurosporine-induced neuronal death: multiple mechanisms and methodological implications

To examine whether multiple pathways of cell death exist in sympathetic neu rons, we studied the cell death pathway induced by staurosporine (STS) in s ympathetic neurons and compared it with the well-characterized NGF deprivat ion-induced death pathway. Increasing concentrations of STS were found to i nduce sympathetic neuronal death with different biochemical and morphologic al characteristics. One hundred nM STS induced metabolic changes, loss of c ytochrome c, and caspase-dependent morphological degeneration which closely resembled the apoptotic death induced by NCF deprivation, In contrast symp athetic neurons treated with 1 mu M STS showed no loss of cytochrome c but exhibited extensive, caspase-independent, chromatin changes that were nat T UNEL positive. One mu M STS-treated sympathetic neurons had greatly reduced metabolic activities and became committed to die rapidly, yet maintained s oma structure and appeared viable by other criteria even up to 48 h after S TS treatment, illustrating the need to assess cell death by multiple criter ia. Lastly, in contrast to the cell death-inducing activities of 100 nM STS or 1 mu M STS, very low concentrations of STS (1 nM STS) inhibited sympath etic neuronal death by acting either at or prior to c-jun phosphorylation i n the NGF deprivation-induced PCD pathway.