Abstract: Objective To investigate the mechanism of DNA damage response(DDR) pathway regulating calcification in human aortic smooth muscle cells(HASMCs). Methods The HASMCs were divided into the control group, model group, ATM treatment group, and PARP treatment group, and they were cultured for 12 days. Cell calcification was measured by Alizarin red staining and σ-Cresolphthalein; phosphorylation levels of histone γH2AX, protein levels of p16 and p21, and phosphorylation levels of ATM on Ser1981 were tested by Western blot, premature cell senescence by β-galactosidase staining; and p16 and p21 mRNA by qPCR. The level of oxidative stress was measured by 8-hydroxy-2′-deoxyguanosine (8-OHDG), and the level of IL-6 and IL-8 was measured by ELISA kit. Results The calcification was evident in the model group as compared with that in control group. There were significant changes in 8-OHDG, histone γH2AX phosphorylation, β -galactosidase staining, mRNA and protein of p16, p21 mRNA, release of IL 6 and IL 8 and ATM phosphorylation(P＜0.05).The changes in the model group alleviated by ATM and PARP treatment. Conclusions High calcium and phosphorus environment stimulates HASMCs to produce sustained DNA damage, triggers ATM phosphorylation, activates p16 protein expression, and induces premature cell senescence causing cell death and resulted in calcification.

Key words: Ca²⁺/P, DNA damage response (DDR), cellular senescence, human aortic smooth muscle cells(HASMCs), vascular calcification