TRIM16 exerts protective function on myocardial ischemia/reperfusion injury through reducing pyroptosis and inflammation via NLRP3 signaling.

Myocardial infarction is still a leading cause of morbidity and mortality worldwide, but its pathogenesis has not been fully understood. In the study, we attempted to explore the effects of E3 ligase tripartite motif 16 (TRIM16) on myocardial ischemia-reperfusion (MI/R) injury in vivo and in vitro, and the underlying mechanisms. We identified that TRIM16 was indeed a potent regulator during MI/R progression in murine models and surprisingly showed a negative correlation with the concentrations of cardiac pro-inflammatory cytokines. Adenoviral vectors encoding GFP or TRIM16 (Ad-TRIM16) were subjected to mice through direct injection into the left ventricular (LV). We found that Ad-TRIM16 significantly reduced the infarct size, and improved the cardiac function and structure compared with the Ad-GFP mice after MI/R operation. More studies indicated that TRIM16 over-expression strongly meliorated nucleotide-binding oligomerization domain-like receptor family pyrin domain containing 3 (NLRP3) inflammasome and associated inflammatory response in hearts of MI/R-induced mice, which were validated in hypoxia/reoxygenation (H/R)-exposed primary cardiomyocytes in vitro. In particular, MI/R operation led to cardiac pyroptosis by increasing the cleavage of Caspase-1 and Gasdermin D (GSDMD), while being considerably abrogated upon TRIM16 over-expression. Mechanistically, TRIM16 interacted with NLRP3 and promoted the K48-linked polyubiquitination of NLRP3, ultimately promoted its degradation. Together, we identified TRIM16 as a novel E3 ubiquitin ligase for NLRP3, which played an essential role in modulating its expression, and subsequently influenced inflammatory response and pyroptosis in MI/R murine model, confirming that TRIM16 may be a potential therapeutic target for myocardial infarction.