Regulation of expression of cGMP-dependent protein kinase Ialpha by calcineurin in vascular smooth muscle cells proliferation

To discuss the regulation of expression of cGMP-dependent protein kinase I(alpha) (PKG I(alpha)) by calcineurin (CaN) in vascular smooth muscle cells (VSMCs) proliferation.Cultured wistar rat aortic VSMCs were used as an experimental model. CaN was inhibited by its special inhibitor cyclosporin A (CsA). Phenylephrine (PE) was given to stimulate VSMCs to proliferate. All of cultured cells were divided into four groups:control group, 0.5 mg/L CsA group, 5 mg/L CsA group and 5 mg/L CsA+10 micromol/L PE group. The mRNA and protein expressions were assayed by RT-PCR, immunocytochemistry and Western blot analysis.The OD ratio of PKG I(alpha) mRNA expression in 0.5 mg/L CsA group resembled that in the control group while that in 5 mg/L CsA group was significantly higher than that in the control group (P<0.01). Although the result of 5 mg/L CsA+10 micromol/L PE group was lower than that in 5 mg/L CsA group (the expression of mRNA decreased 32.2%; the production of PKG I(alpha) protein decreased 36.7%, P<0.01), but still higher than that in the control group obviously (P<0.05). This kind of complexion was also validated by immunocytochemistry and Western blot analysis.CaN is a regulator of PKG I(alpha) expression in cultured VSMCs proliferation. Once CaN was inhibited by its special inhibitor CsA, the expression of PKG I(alpha) increased obviously. And the expression reduced significantly when CaN was actived by PE again.PubMed06595-83