Complement C3 reduces apoptosis in human cardiomyocytes

Complement C3 is a key factor in complement system. Our recently animal study found that C3 may regulate myocardial apoptosis through the intrinsic apoptosis pathway. The current work investigated if C3 regulation of apoptosis occurred in human cardiomyocytes. Our results showed that incubation of exogenous C3 reduced apoptosis in a cell culture system of human cardiomyocytes which did not inherently express C3. In addition, C3 inhibited intrinsic apoptosis pathway in a cell-free apoptosis system. Furthermore, pro-C3 was found to bind with an apoptotic factor, pro-caspase 3, in a cell-free system. Thus, we presented firsthand evidence that exogenous C3 is readily reduce apoptosis in human cardiomyocytes via interaction with the intrinsic apoptotic pathway.