Caspase in renal development.

Apoptosis is an important process for organogenesis and tissue remodelling in various normal and pathological conditions. In the apoptotic pathway, caspases play central roles, and have been studied extensively in the past decade, while their roles in renal development and organogenesis have not been elucidated yet. To reveal the roles of caspases in renal development, we have examined their activities and apoptosis in microdissected metanephroi. In the developing kidney, apoptotic cells showed expression of caspase-3, and inhibition of either caspase-3 or caspase-9 attenuated growth of metanephroi, indicating that the mitochondrial pathway of apoptosis plays major roles in kidney development. In addition, several growth factors are known to be involved in kidney organogenesis, such as hepatocyte growth factor. We currently are examining the roles of these growth factors and their signal transduction system; their roles in kidney organogenesis should be determined in the future.