Human cytomegalovirus (HCMV) may increase the incidence of restenosis and predispose to
atherosclerosis. The lesions of restenosis and
atherosclerosis often contain smooth muscle cells (SMCs) with high rates of proliferation and apoptosis. One of the immediate early (IE) gene products of HCMV-IE2 affects transcriptional activities of some cellular factors in SMCs, including
myocardin. In this study, we studied the effects of IE2 and
myocardin on PI3K pathway inducer
wortmannin induced apoptosis in rat aortic SMCs. We show that the transcriptional activity of
myocardin on Mcl-1 promoter is enhanced by co-expression of HCMV IE2 in rat aortic SMCs; and the expressions of
mRNA and
protein of antiapoptotic genes-Mcl-1 and Bcl-2 are upregulated by IE2 alone and co-transfection of
myocardin and IE2, but decreased by
myocardin-specific
shRNA in rat aortic SMCs. We further demonstrate that co-expression of
myocardin and HCMV IE2 declines apoptotic cell numbers and
caspase-3 activities induced by serum
starvation plus
wortmannin in rat aortic SMCs. The results suggest that HCMV IE2 enhances
myocardin-mediated survival of rat aortic SMCs under serum deprivation and
PI3-kinase inhibition, partly via activation of Mcl-1's antiapoptosis effect. Our study connects HCMV IE2 to
myocardin-induced transcriptional program for rat aortic SMCs survival and proliferation, involving in HCMV related restenosis and
atherosclerosis.