LRRC8A/TRIM21 axis exacerbates myocardial ischemia/reperfusion injury by blocking FAK/NF-κB pathway

Myocardial ischemia-reperfusion (MI/R) injury represents a significant complication associated with reperfusion therapy for myocardial infarction. Leucine-rich repeat-containing protein 8A (LRRC8A), a volume-regulated anion channel protein, involved in cellular homeostasis, has been implicated in the progression of cardiovascular events, but its role in MI/R remains uninvestigated. Here, we sought to characterize the role of LRRC8A in MI/R injury and uncover its potential mechanism. A rat MI/R model was developed via left anterior descending coronary artery ligation for 45 min followed by 4 h reperfusion to assess changes in LRRC8A expression in the myocardium. The results revealed that LRRC8A was upregulated in rat hearts after MI/R injury. To silence LRRC8A expression, we injected adenovirus encoding LRRC8A shRNA into the myocardium of MI/R rats 3 days before ischemic surgery. We observed that LRRC8A silencing in post-MI/R rats reduced myocardial infarct area, suppressed cardiomyocyte apoptosis and enhanced cardiac function. Furthermore, rat H9c2 cells were subjected to oxygen-glucose deprivation/reoxygenation (OGD/R) to simulate MI/R injury in vivo, and the findings indicated that LRRC8A silencing reduced OGD/R-induced cardiomyocyte apoptosis, while its upregulation had an opposite effect, as Bcl-2 expression, Tunel staining demonstrated. Mechanistically, LRRC8A can interact with tripartite motif containing 21 (TRIM21) and subsequently suppress the focal adhesion kinase (FAK)/NF-κB pathway, thereby facilitating cardiomyocyte apoptosis. TRIM21 knockdown eliminated the pro-apoptotic effect of LRRC8A and decreased the inhibitory effect of LRRC8A on the FAK/NF-κB pathway in MI/R rats as well as in OGD/R-exposed cardiomyocytes.