Apelin-13/APJ induces cardiomyocyte hypertrophy by activating the Pannexin-1/P2X7 axis and FAM134B-dependent reticulophagy.

Cardiac hypertrophy is a leading cause of cardiac morbidity and mortality worldwide. Apelin is the endogenous ligand for the G protein-coupled receptor, APJ. Previously, we have revealed that apelin-13 can induce cardiomyocyte hypertrophy by activating the autophagy pathway. However, the precise mechanism through which apelin-13 regulates reticulophagy to participate in cardiomyocyte hypertrophy remains unclear. Herein, we observed that apelin-13-induced cardiomyocyte hypertrophy by activating FAM134B-dependent reticulophagy via the Pannexin-1/P2X7 signal pathway. Furthermore, we found that apelin-13 stimulated the opening of Pannexin-1 hemichannel and increased extracellular ATP (eATP) levels, which activated the P2X7 purinergic receptor. Activation of the Pannexin-1/eATP/P2X7 axis subsequently led to FAM134B-dependent reticulophagy. Moreover, inhibition of the Pannexin-1/P2X7 axis and FAM134B-dependent reticulophagy reversed apelin-13-induced cardiomyocyte hypertrophy. Based on our present findings, apelin-13/APJ induces cardiomyocyte hypertrophy by activating the Pannexin-1/P2X7 axis and FAM134B-dependent reticulophagy.