An Important Role of KDM2B/TLR4/NF-κB p65 Axis in Modulating Myocardial Ischemia-Reperfusion Injury

Abstract

Objective: To examine the effect and related mechanisms of KDM2B (lysine (K)-specific demethylase 2B) on myocardial ischemia-reperfusion injury. Methods: The oxygen glucose deprivation and reperfusion (OGD/R) model was created using H9c2 cells to induce myocardial ischemia-reperfusion injury. With help of flow cytometry, cell cycle and apoptosis were observed. Western blot and qRT-PCR (quantitative real-time polymerase chain reaction) were employed to examine the protein and mRNA (messenger ribonucleic acid) expression of KDM2B, TLR4 (toll-like receptor 4), P65, p-P65 and NLRP3 (NOD-like receptor thermal protein domain associated protein 3). Using enzyme-linked immunosorbent assay (ELISA), IL (interleukin)-1β and TNF-α (tumor necrosis factor-α) concentrations in cell supernatant were detected. Results: OGD/R increased the cell apoptosis, the proportion of S phase cells, and IL-1β and TNF-α concentrations in H9c2 cells. Knockdown of KDM2B promoted the apoptosis, proportion of cells in G0/G1 phase, and the IL-1β and TNF-α concentrations in OGD/R-treated H9c2 cells. Meanwhile, knockdown of KDM2B increased the TLR4, P65 and NLRP3 mRNA and protein expression, as well as the p-P65/P-65 ratio in OGD/R-treated H9c2 cells. However, over-expression of KDM2B exhibited the opposite effects on OGD/R treated H9c2 cells. Conclusions: KDM2B inhibits inflammation and apoptosis of H9c2 cells under hypoxia/reoxygenation via modulating the TLR4/NF-κB (nuclear factor-κB) p65 pathway.