ABSTRACT
AIM:Toinvestigatetheeffectsofcalcitoningene-relatedpeptide(CGRP)onmyocardinexpres-sion and phenotypic switch in vascular smooth muscle cells ( VSMCs) .METHODS:VSMCs were obtained by aortic tissue adherent culture and treated with angiotensin Ⅱ( AngⅡ) , AngⅡ+CGRP or AngⅡ+CGRP +CGRP8-37 .The protein expression of myocardin and the phenotypic proteins of the VSMCs was detected by Western blot .RESULTS:The expres-sion of myocardin in cultured VSMCs showed downregulation along with time expansion .The protein level of myocardin was higher at 48 h and 72 h than that at baseline in the cultured VSMCs (P<0.05).However, the myocardin was lower at 48 h and 72 h than that at baseline after treatment with CGRP in cultured VSMCs (P<0.05).Furthermore, at 48 h in cul-tured VSMCs, the myocardin decreased along with α-smooth muscle actin (α-SMA) (P<0.05), and osteopontin (OPN) increased (P<0.05) in AngⅡ group compared with control group .After treatment with CGRP, the levels of myocardin andα-SMA become higher ( P <0.05 ) but OPN was lower ( P <0.05 ) in CGRP group than those in AngⅡ group. CGRP8-37 abrogated CGRP-induced increase in myocardin and α-SMA and decrease in OPN in CGRP 8-37 group compared with CGRP group .CONCLUSION: CGRP may regulate the phenotypic switch of the VSMCs and maintain the cells in contractile phenotype through the upregulation of myocardin protein , which may be accomplished by the combination of CGRP and its receptor .
