Title: Effect of conditional expression of angiotensin II type 2 receptor gene on mRNA expression of osteopontin in rat vascular smooth muscle cells in culture
Abstract: Objective To investigate the effect of Ang Ⅱ and its receptor antagonist on the osteopontin(OPN) mRNA expression in double stable AT2R expression cell lines of VSMC.Methods To construct the tetracycline-regulatable vector system to transfer angiotensin Ⅱ(AngⅡ) type 2 receptor(AT2R) gene by homologous recombination,and establish the double stable cell lines of rat vascular smooth muscle cells(VSMC) to express AT2R in two step of selection by antibiotic in which the expression levels of AT2R is tightly controled by doxycycline(Dox).The VSMC were divided into 8 groups randomly:un-transfected control group,transfected group,and treatment with AngⅡ,Dox,CV-11974,PD123319 apart or simultaneously group.The effect of overexpression of AT2R on the mRNA expression of OPN were detected by RT-PCR and mmunohistochemistry respectively.And the effects of AT1R antagonist(CV-11974) and AT2R antagonist(PD123319) on aforementioned target were studied.Results The doxcycline(Dox)-on gene expression system can generate high level and regulable expression of AT2R which tightly controled by addition /removal Dox.The expression of AT2R were induced obviously in double stable VSMC within 48h by addition Dox and further.enhanced after 72h(P0.01).In the well established double stable VSMC lines,addition of AngⅡ resulted in a increase of the expression of the OPN(P0.01).The OPN expression decreased by treatment with Dox(P0.01).Dox-induced decreased expression of OPN were further enhanced by CV-11974(P0.01),and were removed by PD123319.There are no difference in expression of OPN between CV-11974,PD123319 simultaneously group with control group.Conclusion The enhancement effect of AngⅡ on the expression of OPN is mediated by AT1R and inhibited by AT2R expression.It is suggestded that AT2R acts an antagonistic effect against AT1R in those biological effect.The regulable expression of AT2R might be control of vascular smooth muscle cell proliferation,migration and phenotype by regulation the the expression of OPN.
Publication Year: 2007
Publication Date: 2007-01-01
Language: en
Type: article
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