Effect of PP~(60c-Src) on Ang II- induced signal transduction in rat vascular smooth muscle cells* / 中国病理生理杂志

ABSTRACT

AIM: The aim of the present study was to clar ify the mechanism of intracellular signal transduction in Ang II-induced prolife ration of vascular smooth muscular cells (VSMC) by observing the effect of c-Src on Ang II-mediated mitogen-activated protein kinase (MAPK) activation and c-Fos protein expression in cultured VSMC of rats. METHODS: Cultured aortic VSMCs from SD rats were transfected wit h anti-sense c-Src oligodeoxynucleotides (ODNs) wrapt with lipofectin to inhibit c-Src activity and protein production. Untransfected VSMCs were used as control . We observed the role of Ang II stimulation in MAPK activation and c-Fos protei n expression. c-Src kinase activity was measured by protein immunoprecipitation and kinase autophosphorylation. The phosphorylation rate of the substrate myeli n basic protein (MBP) was employed to assess MAPK activity. Western immunoblot w as used to detect protein expression of c-Src and c-Fos. RESULTS: c-Src protein expression in VSMC transfected with diffe rent concentrations of anti-sense ODNs significantly decreased in a negative dos e-effect manner. c-Src kinase activity was also markedly inhibited . Following t he stimulation of Ang II on transfected VSMCs with anti-sense ODNs, the increase rate of c-Src activity was 8.7% of that in control, the activity of MAPK was 1 .6% compared with control and c-Fos protein expression was as 30.0% as that of control. CONCLUSION: Ang II induces c-Src activation. MAPK activation and c-Fos protein expression by Ang II is dependent on c-Src activation. These find ings indicate that c-Src is an important signal factor in Ang II -induced VSMC proliferati on.