Divergent effects of estrogen and nicotine on Rho-kinase expression in human coronary vascular smooth muscle cells.

Recent studies have demonstrated that up-regulated Rho-kinase plays an important role in the pathogenesis of coronary arteriosclerosis and vasospasm. We have shown that inflammatory stimuli, such as angiotensin II and interleukin-1beta, up-regulate Rho-kinase expression and activity in human coronary vascular smooth muscle cells, for which intracellular signal transduction mediated by protein kinase C and NF-kappaB is involved. Here, we show that estrogen down-regulates while nicotine up-regulates Rho-kinase and that nicotine counteracts the inhibitory effect of estrogen on angiotensin II-induced Rho-kinase expression. Furthermore, we demonstrated that the intracellular signal transduction of the inhibitory effect of estrogen is mediated by an estrogen receptor. These results demonstrate that inflammatory stimuli up-regulate Rho-kinase, for which estrogen (mediated by an estrogen receptor) and nicotine exert divergent inhibitory and stimulatory effects on the Rho-kinase expression, respectively, and may explain in part why the incidence of arteriosclerotic and vasospastic disorders is increased in postmenopausal women and smokers.