Effects of CXCR4 DNA Methylation Remodeled by TET2 on Autophagy,Inflammation and Apoptosis of Myocardial Tissue in Mice with Acute Myocardial Infarction
Objective:To explore the effect of tet methylcytosine dioxygenase 2(TET2)on DNA methylation of C-X-C motif receptor 4(CXCR4)during acute myocardial infarction(AMI),and the mechanism of its effect on myocardial autophagy,inflammation and apoptosis in AMI mice.Methods:Fifty 8-week-old male C57/BL6 mice AMI model were prepared,TET2 and CXCR4 overexpressing plasmids were injected into the tail.The expressions of TET2,CXCR4,microtubule associated protein 3(LC3),P62,B-cell lymphoma/leukemia-2 gene(Bcl-2)associated X protein(Bax),Caspase-3,and Bcl-2 in cardiac tissue were detected by Western Blot.The methylation level of CXCR4 DNA was detected.The levels of inflammatory factors interleukin-6(IL-6),tumor necrosis factor-α(TNF-α)and interleukin-1β(IL-1β)in myocardial tissue were detected by enzyme-linked immunosorbent assay(ELISA).Terminal deoxyribonucleotidyl transferase(TdT)-mediated dUTP nick end labeling(TUNEL)was used to detect apoptosis index of myocardial tissue in each group.Results:Compared with sham operation group,the expressions of TET2 and CXCR4 up-regulated in myocardial tissue of model group,and both TET2 and CXCR4 overexpressed in myocardial tissue,and overexpression of TET2 promoted CXCR4 expression(P<0.05).Compared with model group,DNA methylation of CXCR4 promoter region decreased and CXCR4 protein expression increased in TET2 mimic group(P<0.05).Compared with sham operation group,expressions of autophagy protein LC3 and apoptosis inhibiting protein Bcl-2 down-regulated in myocardial tissue of mice in model group,and levels of inflammatory factors IL-6,TNF-α,IL-1β,autophagy protein P62,pro-apoptotic protein Bax,cleaved Caspase-3 up-regulated(P<0.05).Overexpression of TET2 and CXCR4 further down-regulated the expression of LC3 and Bcl-2 proteins,up-regulated the levels of inflammatory factors IL-6,TNF-α,IL-1β,and expression of P62,Bax,cleaved Caspase-3 proteins.TET2 and CXCR4 showed the lowest LC3 and Bcl-2 protein expression,the highest inflammatory factors IL-6,TNF-α,IL-1βlevels,P62,Bax,cleaved Caspase-3 protein expression(P<0.05).Conclusion:In the development of AMI,TET2 can promote CXCR4 gene expression by reducing CXCR4 DNA methylation,thereby inhibiting myocardial autophagy in AMI mice,up-regulating inflammatory response and apoptosis,and promoting the development of the disease.
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维普
