Inhibition of TRPM7 Attenuates Rat Aortic Smooth Muscle Cell Proliferation Induced by Angiotensin II: Role of Genistein

Transient receptor potential melastatin 7 (TRPM7) is a Ca2+, Mg2+ permeable nonselective cation channel of the TRP channel superfamily and plays an important role in cell growth and proliferation. Compounds that alter the activity and expression of the channel protein might be of therapeutic interest. In this study, we investigated the effects of genistein on TRPM7 channels and the proliferation of rat aortic smooth muscle cells (RAoSMCs). In primary cultured RAoSMCs, acute genistein (50 mu M) exposure inhibited native TRPM7 currents, whereas chronic expose to genistein (50 mu M) downregulated TRPM7 protein expression. The downregulation of TRPM7 protein expression induced by genistein was mimicked by c-Src inhibitor (PP2), but not by epidermal growth factor receptor tyrosine kinase inhibitor (lavendustin A), or daidzein. Additionally, genistein (50 mu M) attenuated angiotensin II-induced cell proliferation. This study is the first to demonstrate inhibition of TRPM7 by isoflavone genistein through c-Src tyrosine kinase inhibition in RAoSMCs. Our results not only provide a new modulation mechanism of TRPM7 but also suggest that TRPM7 may serve as a new therapeutic target of genistein in the treatment of vascular diseases.