PROTECTIVE EFFECT OF PGC-1Α ON HUMAN UMBILICAL VEIN ENDOTHELIAL CELLS

Guangqin Liu^#, Yifei Pei^#, Zaiping Jing, Liangxi Yuan, Jian Dong, Jian Zhou, Junmin Bao^* 

Department of Vascular Surgery, Changhai Hospital, The Navel Military Medical University, Shanghai, PR China

Objective: PGC-1α achieves the protective effect of TNF-α-induced injury to human umbilical vein endothelial cells by inhibiting the Ca²⁺/NFAT pathway.

Methods: Human umbilical vein endothelial cells were treated with 20, 40, and 80 ng/mL TNF-α to create three models with different degrees of cell injury. The human umbilical vein endothelial cells were cultured in vitro and transfected by interfering with the PGC-1α RNA lentivirus. The silencing of the PGC-1α gene was divided into two groups: the control group and the down-regulation of the PGC-1α gene group. The effects of different concentrations of TNF-α on apoptosis of human umbilical vein endothelial cells were determined by flow cytometry. The expression of intracellular genes was detected by real-time quantitative PCR, and the expression of intracellular protein was measured by western blot assay. The concentrations of mtROS and Ca²⁺ were measured.

Results: After human vein endothelial cells were treated for 24 h with different concentrations of TNF-α, the apoptosis rate gradually increased with the increase of TNF-α concentration, and the difference was statistically significant compared with the control group (P<0.05). The expression of PGC-1α mRNA in each group was significantly lower than that of the control group after human venous endothelial cells were treated for 24 h of with different concentrations of TNF-α (P<0.05). After treatment with different concentrations of TNF-α, the relative expression rate of PGC-1α protein in each group was remarkably lower than that in the control group (P<0.05). The expression of NFAT1 mRNA in the TNF-α 40 and 80 ng/mL treatment groups was significantly higher than that in the control group (P<0.05), and the expression of NFAT2 mRNA in different concentrations of the TNF-α treatment groups was markedly higher than that in the control group (P<0.05). The expression of NFAT1 protein in the TNF-α 40 and 80 ng/mL treatment groups was significantly higher than that in the control group (P<0.05), and the expression level of NFAT2 protein in different concentrations of TNF-α treatment group was clearly higher than that in the control group (P<0.05). The intracellular mROS and Ca²⁺ concentrations were significantly higher than that in the control group after the down-regulation of the PGC-1α gene expression (P<0.05). After down-regulating the expression of the PGC-1α gene, the levels of NFAT1, NFAT2, mRNA, and protein in the cells were significantly higher than those in the control group (P<0.05).

Conclusion: 20, 40, and 80 ng/mL of TNF-α can induce different degrees of human umbilical vein endothelial cell injury. PGC-1α has a protective effect on this kind of cell injury, and its related mechanism may be to inhibit the Ca²⁺/NFAT signalling pathway by reducing the intracellular mtROS concentration, and thus to protect damaged cells.