Apoptosis in Retinal Pigment Epithelial Cells

Abstract

Abstract: : Purpose:To characterize the means by which retinal pigment epithelial cells die compared to the Jurkat T-cell line. Methods:RPE cells and Jurkat cells were exposed to apoptotic stimuli by addition of NaIO3, ceramide and staurosporine. Cyclosporin A, FK506, verapamil and ZVAD were tested for their ability to prevent apoptosis. The apoptotic response was monitored by using a MTT-assay and a caspase-3 assay. Results:NaIO3 were capable of inducing apoptosis in RPE cells in a concentration ranging from 1mM to 8 mM whereas Jurkat cells was largely unaffected. Both ceramide and staurosporine were capable of inducing apoptosis in Jurkat cells in a concentration of 50-200 uM and 0,3 - 4 ug/ml, respectively, whereas RPE cells was unaffected. Induction of apoptosis was followed by significantly increased caspase-3 activity in Jurkat cells, whereas no increase in caspase-3 activity was observed in RPE cells. Cyclosporin A was able to inhibit NaIO3 induced apoptosis in RPE cells, whereas verapamil, FK506 and ZVAD could not prevent apoptosis. Conclusion:RPE cells are susceptible to NaIO3 induced apoptosis, but not to ceramide and staurosporine induced apoptosis. Caspase 3 seems not to be involved in RPE induced apoptosis in contrast to apoptosis induced in Jurkat cells. Inhibition of NaIO3 induced apoptosis in RPE cells by Cyclosporin A but not by verapamil or FK506, indicate involvement of Cyclophilin D in RPE apoptosis.

Keywords: 323 apoptosis/cell death • 567 retinal pigment epithelium • 379 cyclosporine