The expression of SIRT3 signaling in hypoxia-induced endothelial injury

Background Oxidative injury to the endothelial cells plays an important role in development of atherosclerosis. Investigation of the mechanisms of oxidative endothelial injury is of great importance. Our previous report has demonstrated that Sirtuin 3（SIRT3） protect cardiomyocytes from oxidative stress-mediated cell death via activating the nuclear factor kappa-B（NF-κB） signaling pathway. However, the role and exact mechanisms of SIRT3 signaling in endothelial hypoxia injury are largely unknown. The present study aimed to investigate the expression of SIRT3, hypoxia-inducible factor 1α（HIF-1α）, and NF-κB/TNF-α（tumor necrosis factor-α） in human umbilical vein endothelial cells（HUVECs） treated by hypoxia. Methods Hypoxia model was established by anoxic tank and randomly divided into 3 groups: control group, 1 h hypoxia group, and 3 h hypoxia group. 3-（4, 5-dimetrylthiazol-2-yl）-2, 5-diphenyltetrazolium bromide（MTT） detected the cell viability under hypoxia condition, and the intracellular reactive oxygen species（ROS） generation was determined by 2′, 7′-Dichlorodihydrofluorescein diacetate（DCFH-DA）. The expression of m RNA and protein of the SIRT3 signaling were detected by real-time quantitative polymerase chain reaction（q PCR） and western blot analysis, respectively. Results Hypoxia treatment time-dependently decreased the cell viability, especially in the first hour. ROS production significantly increased in the first hour of hypoxia compared with those in the second and the third hour. Hypoxic stimuli significantly elevated SIRT3 m RNA and protein expression. Furthermore, real-time q PCR results showed that elevated SIRT3 significantly increased the m RNA expression of HIF-1α and NF-κB/TNF-α in 1 h hypoxia group. Western blot results also showed that elevated SIRT3 significantly increased the protein expression of NF-κB in the 1 h hypoxia group. Conclusions The present study indicated that hypoxic stimuli promoted the expression of SIRT3,HIF-1α, and NF-κB/TNF-α, and suggested that SIRT3 signaling pathway may participate in the physiological process of acute ischemic hypoxia stress in human endothelial cells.[S Chin J Cardiol 2020;21（4）:277-284]