Mycophenolic acid mediated mitochondrial membrane potential transition change lead to T lymphocyte apoptosis

Abstract

Purpose: This study demonstrated that apoptosis induced by mycophenolic acid (MPA) is mediated by mitochondrial membrane potential transition (MPT) changes in Jurkat cells. Methods: Cell viability and MPT changes were measured by flow cytometry. Western blotting was performed to evaluate the expression of Bcl-2 family proteins, Bid, truncated Bid (tBid), cytochrome c, voltage dependent anion channel (VDAC), poly ADP-ribose polymerase (PARP), and protein kinase C-™ (PKC-™). The catalytic activity of caspase-9 and-3 was also measured. Results: Cell viability was decreased in time-and dose-dependent manners. Bcl-2 protein expression was decreased, but Bax protein expression was identified. A decreased Bcl-XL /Bcl-XS ratio was also noted. The expression of tBid protein also increased in a time-dependent manner in Jurkat cells treated with MPA. While normal MPT appeared as orange fluorescence, abnormal MPT corresponded to green fluorescence. Green fluorescence increased as orange decreased in the MPA-treated cells. Significantly increased concentrations of MPA induced the release of cytosolic cytochrome c. MPA also augmented the catalytic activity of caspase-9 and caspase-3 in Jurkat cells. Our findings demonstrated that MPA-induced apoptosis is mediated by MPT changes accompanied by decreased Bcl-XL expression and the appearance of tBid protein. The release of cytosolic cytochrome c from mitochondria and increased catalytic activity of caspase-9 and caspase-3 were observed in MPA-treated Jurkat cells. Conclusion: These results suggest that mitochondrial dysfunction caused by MPA induces human T lymphocyte apoptosis. Copyright © 2011, the Korean Surgical Society.