Inhibitory Effect of Paeonol on Vascular Smooth Muscle Cell Senescence by Reducing SIRT6/PARP1-mediated DNA Damage / 中国实验方剂学杂志

ABSTRACT

ObjectiveTo investigate whether the effects of paeonol （Pae） on angiotensin Ⅱ （AngⅡ）-induced senescence in vascular smooth muscle cells （VSMCs） were related to angiotensinogen of silencing regulatory information factor 6 （SIRT6）/adenosine diphosphate ribose polymerase 1 （PARP1） signaling pathway in VSMCs. MethodThe model of VSMC-stress aging induced by AngⅡ （100 nmol·L-1） was established. The rats were divided into normal group， model group， low， medium， and high-concentration Pae groups （30， 60， 120 μmol·L-1）. The positive rate of cell senescence was detected by SA-β-Gal staining， the ability of cell proliferation was detected by the cell counting kit-8 （CCK-8） method， the expression of SIRT6， PARP1， p16， p21， p53， proliferating cell nuclear antigen （PCNA）， deoxyribonucleic acid （DNA）-damaged protein γ-H2AX was detected by Western blot， and VSMC proliferation was detected by EdU staining. The silenced VSMCs were prepared by siRNA-SIRT6 transfection， and the protein expressions of SIRT6， PARP1， p16， and γ-H2AX in VSMCs silenced by SIRT6 were observed. ResultThe results of SA-β-Gal staining showed that the senescence positive rate of SA-β-Gal staining in the model group was higher than that in the normal group （P<0.01）， and the positive rate of SA-β-Gal staining in the Pae group was significantly lower than that in the model group （P<0.05， P<0.01）. The results of Western blot showed that as compared with the normal group， the expression of PCNA， SIRT6， and PARP1 in the model group was down-regulated， and the expression of aging-related proteins p16， p21， p53， and γ-H2AX was up-regulated in the model group （P<0.05， P<0.01）. Compared with the model group， Pae promoted the protein expression of PCNA， SIRT6， and PARP1 and inhibited the protein expression of p16， p21， p53， and γ-H2AX in a dose-dependent manner （P<0.05， P<0.01）. The results of EdU staining showed that the number of EdU positive cells in the model group was lower than that in the normal group （P<0.01）， and the number of EdU positive cells in Pae groups was significantly higher than that in the model group （P<0.05， P<0.01）. After SIRT6 silencing， the effects of Pae on promoting SIRT6 and PARP1 and inhibiting P16 were reversed （P<0.05， P<0.01）. In addition， the addition of SIRT6 inhibitor （IN-1） promoted the occurrence of cell senescence induced by AngⅡ （P<0.05， P<0.01）. ConclusionPae can effectively inhibit the aging of VSMCs， and its mechanism may be related to the regulation of SIRT6/PARP1 signal pathway.