Effects of down-regulation of protein kinase C on activation of storeoperated Ca~(2+) channels and the proliferation of airway smooth muscle cells / 中国病理生理杂志

ABSTRACT

AIM:To investigate the effects of down-regulation of protein kinase C (PKC) on the activity of storeoperated Ca2 + channels (SOC) and the proliferation of airway smooth muscle cells (ASMCs). METHODS:Rat bronchial smooth muscle cells were isolated and cultured. Fluo-3 /AM fluorescence was measured by laser confocal microscope to assessing intracellular Ca2 +. Downregulation of PKC activity was achieved by incubation of ASMCs with PKC activator phorbol-12-myristate-13-acetate (PMA,10 ?mol/L) or phorbol 12,13 -dibutyrate (PDBu,1 ?mol/L) for 24 h. The proliferation of ASMCs was assayed by calculating the reduction rates of Alamar blue. RESULTS:Down-regulation of PKC activity by longterm exposure of PMA or PDBu inhibited the proliferation of ASMCs,the similar results were obtained by using PKC inhibitor chelerythrine. Both downregulation of PKC activity and inhibition of PKC activity by chelerythrine reduced Ca2 + entry through SOC channels. Low concentration of PMA (0. 1 ?mol/L) promoted the proliferation of ASMCs,and this effect was inhibited by SOC blocker SKF-96365. CONCLUSION:Inhibition or down -regu-lation of PKC activity results in the inhibition of SOC channels,suggesting that PKC is involved in the activation of these channels. Ca2 + entry through SOC channels might contribute to PKC-promoted proliferation of ASMCs.