Angiotensin II Is Involved in MLKL Activation During the Development of Heart Failure Following Myocardial Infarction...

Several reports assume that myocardial necroptotic cell death is induced during the development of chronic heart failure. Although it is well accepted that angiotensin II induces apoptotic cell death of cardiac myocytes, the involvement of angiotensin II in the induction of myocardial necroptosis during the development of heart failure is still unknown. Therefore, we examined the role of angiotensin II in myocardial necroptosis using rat failing hearts following myocardial infarction and cultured cardiomyocytes. We found that administration of azilsartan, an angiotensin II AT₁ receptor blocker, or trandolapril, an angiotensin-converting enzyme inhibitor, to rats from the 2nd to the 8th week after myocardial infarction resulted in preservation of cardiac function and attenuation of mixed lineage kinase domain-like (MLKL) activation. Furthermore, the ratio of necroptotic cell death was increased in neonatal rat ventricular cardiomyocytes cultured with conditioned medium from rat cardiac fibroblasts in the presence of angiotensin II. This increase in necroptotic cells was attenuated by pretreatment with azilsartan. Furthermore, activated MLKL was increased in cardiomyocytes cultured in conditioned medium. Pretreatment with azilsartan also prevented the conditioned medium-induced increase in activated MLKL. These results suggest that angiotensin II contributes to the induction of myocardial necroptosis during the development of heart failure.