Cytoprotection by nipradilol, an anti-glaucomatous agent, via down-regulation of apoptosis related gene expression and activation of NF-κB

It has been reported that nipradilol, a nonselective β- and selective α1-receptor antagonist, has cytoprotective effects. We attempted to clarify the effects of nipradilol on the expression of apoptosis associated genes and the activity of nuclear factor-κB, a transcription factor, in PC12 cells during serum deprivation induced apoptosis. PC12 cells were cultured in serum free RPMI1640 medium with or without 0·01, 0·1, 1, or 10 μm of nipradilol, or in serum-added medium as a control. The gene expressions of Bax, Bcl-2, Fas, FasL, Caspase-1, 2, 3, and 9, p53, and Smac/DIABLO were examined using a quantitative real time polymerase chain reaction method, while nuclear factor-κB activity was examined using an electrophoresis mobility shift assay with a nuclear factor-κB consensus sequenced DNA probe. The effects of denitronipradilol were also examined to clarify the effect of nitric oxide donative action. Nipradilol down-regulated Bax gene expression 12 hr after serum deprivation, and that of the capase-9 and Smac/DIABLO genes at 24 hr, compared to the serum-free sample, while it also increased cell viability and decreased DNA ladder formation at 48 hr. However, the expressions of other examined genes were not affected by the agent. In addition, nuclear factor-κB activity was increased 2 hr after the addition of 0·1 or 1 μm of nipradilol. In contrast, denitronipradilol did not show any effects toward PC12 cells. Our results suggest that nipradilol may have an effect on apoptosis associated gene expression and nuclear factor-κB activity during the prevention of apoptosis via nitric oxide donative action.