Mitochondria and caspases in induced apoptosis in human luteinized granulosa cells

Apoptosis occurs as a physiologic process in the ovarian life cycle. Stauro sporine, a protein kinase inhibitor, is reported to induce apoptosis. Here, we hypothesize that staurosporine will induce apoptosis in human luteinize d granulosa cells and that mitochondria and the caspase cascade participate in this pro cess. Luteinized granulosa cells isolated from in vitro fertil ization patients were treated with staurosporine. Microscopy revealed that staurosporine treatment resulted in cells exhibiting evidence of apoptosis, including cell detachment, loss of cell processes, membrane shrinkage, and formation of apoptotic bodies. In the staurosporine-treated cells, how cyt ometry and confocal microscopy showed a decrease in the mitochondrial cardi olipin levels. Western analysis showed cleavage of caspase-9, an initiator caspase, of caspase-3, an executioner caspase, and of a caspase substrate, poly-(ADP-ribose)-polymerase (PARP) in staurosporine-treated cells. These d ata support our hypothesis and that this is the first demonstration of the involvement of mitochondria and of cleavage of caspases in human luteinized granulosa cell apoptosis. This may serve as a useful model to delineate th e mechanism of apoptosis in the ovary, such as corpus luteum regression. (C ) 2000 Academic Press.