[Inhibitory effect of Sirt3 on proliferation of vascular smooth muscle cells induced by angiotensin II].

OBJECTIVE: To detect the expression of Sirtuin3 (Sirt3) in mice vascular smooth muscle cells (VSMCs) and explore the effect of Sirt3 on VSMCs proliferation induced by angiotensin II (AngII).

METHODS: The mRNA and protein expressions of Sirt3 in wild C57 mice VSMCs were assessed by RT-PCR and Western blotting, respectively. After the cells were exposed to various concentrations of AngII (10(-7);, 10(-6);, 10(-5); mol/L), the mRNA and protein expressions of Sirt3 were assessed again in the same way. The effect of Sirt3 on cell proliferation was observed with Edu (5-ethynyl -2'-deoxyuridine) kit after Sirt3 silencing by small interference RNA.

RESULTS: Sirt3 was stably expressed in C57 mice VSMCs as revealed by Western blotting and RT-PCR, respectively. A significant increase was found in the mRNA and protein expressions of Sirt3 (P<0.01) after the stimulation of all the three different concentrations of AngII, particularly the 10(-6); mol/L group with the highest increase of Sirt3 expression, and there was a significant difference between the 10(-6); mol/L group and the other groups (P<0.05). The rate of cell proliferation in Sirt3 SiRNA group increased obviously compared to the control group (P<0.01), and the rate in the Sirt3 SiRNA+AngII group was also elevated significantly compared to the AngII group (P<0.01).

CONCLUSION: The expression of Sirt3 is stable in VSMCs; AngII can elevate the mRNA and protein expression of Sirt3 and promote the cell proliferation, what's more, Sirt3 silencing would further increase the cell proliferation.