Inhibition of GSDMD Activates Poly(ADP-ribosyl)ation and Promotes Myocardial Ischemia-Reperfusion Injury

The precise control of cardiomyocyte viability is imperative to combat myocardial ischemia-reperfusion injury (I/R), in which apoptosis and pyroptosis putatively contribute to the process. Recent researches indicated that GSDMD is involved in I/R as an executive protein of pyroptosis. However, its effect on other forms of cell death is unclear. We identified that GSDMD and GSDMD-N levels were significantly upregulated in the I/R myocardium of mice. Knockout of GSDMD conferred the resistance of the hearts to reperfusion injury in the acute phase of I/R but aggravated reperfusion injury in the chronic phase of I/R. Mechanistically, GSDMD deficiency induced the activation of PARylation and the consumption of NAD+ and ATP, leading to cardiomyocyte apoptosis. Moreover, PJ34, a putative PARP-1 inhibitor, reduced the myocardial injury caused by GSDMD deficiency. Our results reveal a novel action modality of GSDMD in the regulation of cardiomyocyte death; inhibition of GSDMD activates PARylation, suggesting the multidirectional role of GSDMD in I/R and providing a new theory for clinical treatment.