Role of SIRT3 in Angiotensin II-induced human umbilical vein endothelial cells dysfunction

SIRT3, a member of the sirtuin family of NAD(+)-dependent deacetylases, resides primarily in the mitochondria and has been shown to deacetylate several metabolic and respiratory enzymes that regulate important mitochondrial functions. Previous researches show an important role of SIRT3 in regulating the production of reactive oxygen species (ROS), and highlight the ability of SIRT3 to protect cells from oxidative damage. A key substance of renin-angiotensin-aldosterone system (RAAS), Angiotensin II (AngII) can induce cells dysfunction by increasing the production of ROS. In this paper, we focus on the role of SIRT3 in AngII-induced human umbilical vein endothelial cells (HUVECs) dysfunction.

To study the influence of AngII on SIRT3 expression, HUVECs were treated with AngII of 10(-7), 10(-6), 10(-5) mol/L for 24 h. SIRT3 expression was detected by wester-blotting analysis and RT-PCR. In addition, to research the role of SIRT3 in AngII-induced HUVECs,we used SIRT3 siRNA to knock down SIRT3 expression in HUVECs. Cells pretreated with negative control siRNA or SIRT3 siRNA were exposed to AngII for 24 h, and endothelial nitric oxide synthase (eNOS) expression, eNOS activity, total level of nitric oxide (NO) and ROS generation of each group were detected.

Here we show that AngII treatment could increase generation of ROS, and decrease eNOS activity and total level of NO, while upregulated eNOS expression as a compensatory mechanism. The stimulation of AngII upregulated the expression of SIRT3 in HUVECs. SIRT3 siRNA worsen the AngII-induced effects above, besides, downregulated eNOS protein expression.

These data suggest that SIRT3 plays a role of protection in AngII-induced HUVECs dysfunction via regulation of ROS generation.