ULK1 activates NCOA4‑mediated ferritinophagy via the Beclin1/VPS34 complex in cardiomyocyte hypertrophy.

Cardiac hypertrophy is associated with ferroptosis. Serine/threonine protein kinase ULK1 (ULK1) acts as a key activator of autophagy; however, its exact function in the non‑autophagy pathway remains to be fully elucidated. The present study aimed to decipher the role and mechanisms of ULK1 in ferroptosis and cardiomyocyte hypertrophy. Cell survival, lipid peroxidation, iron metabolism and prostaglandin endoperoxide synthase 2 (Ptgs2) mRNA expression were analyzed to investigate the role of ferroptosis in ULK1‑silenced or ULK1‑overexpressing HL‑1 cells. Immunofluorescence staining, western blot analysis and monomeric red fluorescent protein‑green fluorescent protein‑microtubule‑associated protein 1 light chain 3 puncta formation assays were performed to demonstrate the regulatory effect of ULK1 on autophagy and ferritinophagy‑related proteins. Ferritinophagy activation was assessed in cardiomyocytes using immunofluorescence of nuclear receptor coactivator 4 (NCOA4) and microtubule‑associated protein 1 light chain 3‑II colocalization. ULK1 expression was found to be elevated in both transverse aortic constriction‑induced hypertrophic cardiac tissues and angiotensin II‑treated cardiomyocytes. ULK1 knockdown markedly suppressed cardiomyocyte ferroptosis, whereas ULK1 overexpression facilitated ferroptosis in HL‑1 cells. Meanwhile, the ferroptosis inhibitor ferrostatin‑1 reduced iron accumulation, lipid peroxidation and Ptgs2 mRNA expression. Notably, the autophagy inhibitor 3‑methyladenine mitigated ULK1‑induced ferroptosis. Mechanistically, ULK1‑activated NCOA4‑mediated ferritinophagy was found to be dependent on the Beclin1/PI3K catalytic subunit type 3 complex. Finally, the ULK1 inhibitor SBI‑0206965 ameliorated ferroptosis in cardiomyocytes in vitro. For the first time, to the best of our knowledge, the present study demonstrated that ULK1 modulates NCOA4‑mediated ferritinophagy and ferroptosis in HL‑1 cells. The findings of the present study provide a novel insight into the progression of cardiomyocyte hypertrophy.