TRIM38 protects H9c2 cells from hypoxia/reoxygenation injury via the TRAF6/TAK1/NF-κB signalling pathway

Tripartite motif (TRIM) 38 is a ubiquitin E3 protein ligase that is involved in various intracellular physiological processes. However, the role of TRIM38 in myocardial ischaemia/reperfusion (I/R) injury remains to be elucidated. We aimed to establish an in vitro cellular hypoxia/reperfusion (H/R) model to explore the role and potential mechanisms of TRIM38 in H9c2, a rat cardiomyoblast cell line. Recombinant adenoviruses for silencing or overexpressing TRIM38 were constructed and transfected into H9c2 cells. Western blotanalysisshowed that TRIM38 expression was significantly decreased after H/R injury. Functionally, TRIM38 expression relieved inflammatory responses and oxidative stress, and inhibited H/R-induced apoptosis in H9c2 cells. Mechanistically, TRIM38 overexpression inhibited H/R-induced transforming growth factor beta-activated kinase 1 (TAK1)/nuclear factor-kappa B (NF-κB) pathway activity in H9c2 cells. The opposite results were observed after TRIM38 knockdown. Furthermore, H/R-induced injury aggravated by TRIM38 deficiency in H9c2 cells was reversed upon treatment with 5Z-7-oxozeaenol, a TAK1 inhibitor. Therefore, TRIM38 reduction attenuated the anti-apoptotic capacity and anti-inflammatory potential of H/R-stimulated H9c2 cells by activating the TAK1/NF-κB signalling pathway. Specifically, TRIM38 alleviated H/R-induced H9c2 cell injury by promoting TNF receptor-associated factor 6 degradation, which led to the inactivation of the TAK1/NF-κB signalling pathway. Thus, our study provides new insights into the molecular mechanisms underlying H/R-induced myocardial injuries.