Effect of conditional expression of angiotensin II type 2 receptor gene on mRNA and protein expression of fibronectin in rat vascular smooth muscle cells in vitro

Objective To investigate the effect of AngⅡ and its receptor antagonist on the fibronectin(FN)mRNA and protein expression in VSMC of double stable AT2R expression.Methods VSMC was established,in which the expression levels of AT2R is tightly controlled by Doxycycline(Dox).The VSMC were treated with AngⅡ,Dox,CV-11974,PD123319.The effect of AT2R overexpression on the mRNA and protein expression of FN in VSMC were detected and the effects of AT1R antagonist(CV-11974)and AT2R antagonist(PD123319)on aforementioned target were studied.Results The Dox-on gene expression system could generate high-level,regulable expression of AT2R that was tightly controlled by addition or removal of Dox.The AT2R expression were induced obviously in double stable VSMC within 48 h by Dox and further enhanced after 72 h(P0.01).In the well established double stable VSMC,the addition of AngⅡ resulted in an increase of the FN expression(P0.01).The FN expression decreased after Dox treatment(P0.01).The decreased expression of FN induced by Dox was further enhanced by CV-11974(P0.01),and were removed by PD123319.There was no difference in FN expression between CV-11974 and PD123319 simultaneous group and control group.Conclusion The enhancement effect of AngⅡ on the FN expression is mediated by AT1R and inhibited by Dox-induced AT2R expression.It is suggested that AT2R acts an antagonistic effect against AT1R in those biological effect.