BRD4 inhibition by JQ1 protects against LPS-induced cardiac dysfunction by inhibiting activation of NLRP3 inflammasomes

Background: JQ1, a BRD4 Inhibitor, first identified its therapeutic role in Cancer, has gradually demonstrated a protective effect on the heart in recent years; however, it is unclear whether JQ1 also plays a role in LPS-induced cardiac dysfunction.

Methods and results: A total of forty eight mice were randomly divided into control, LPS(7.5 mg/kg), and LPS + JQ1 (50 mg/kg). JQ1 was preprotected for 1 h, and LPS was stimulated for 12 h, mouse survival and cardiac function were observed, and histopathological, serum myocardial injury markers, and inflammatory indicators, and oxidative stress levels in heart tissue were examined. The experiment found that the cardiac BRD4 levels were upregulated and the heart severe damage in the LPS group compared with the control group. While compared with the LPS group, JQ1 preprotected increased survival rate and cardiac function, reducated cardiomypathological injury and CD45 infiltration, and reduced the release of LDH, CK-MB, IL-1, IL-18, reduced MDA generation, and increased SOD viability. In addition, JQ1 preprotected also upregulated SIRT1, and inhibited the expression of NLRP3, caspase-1p20, and GSDMD. Meanwhile, similar results were obtained in LPS-treated H9C2 cells, and further intervention with the SIRT1 Inhibitor EX527 partially blocked the JQ1-mediated down regulation of NLRP3, caspase-1p20, and GSDMD.

Conclusions: We propose that JQ1 may improve LPS-induced cardiac dysfunction by inhibiting SIRT1-dependent activation of NLRP3 inflammasomes, which may be a promising strategy for treating sepsis cardiomyopathy.