Knockdown of Smurf1 Promotes Autophagy‐Dependent Ferroptosis in Acute Liver Failure by Inhibiting Ubiquitin‐Mediated Ulk1 Degradation

Treating acute liver failure (ALF) relies on rescuing dying hepatocytes and restoring liver regeneration. Ferroptosis contributes to ALF development, so regulating iron homeostasis or lipid peroxide production may be an effective treatment strategy. Ubiquitination can modify ferroptosis and is involved in liver diseases. The study aims to explore the mechanism of E3 ubiquitin ligase Smurf1 regulating ferroptosis in acute liver failure. Screened using proteomics, bioinformatics and experimental verification, we identified Smurf1, a ubiquitin-related protein associated with ferroptosis. Functional experiments were used to verify that Smurf1 regulates hepatocyte ferroptosis and acute liver failure. Furthermore, ubiquitination assays, western blotting and Co-IP experiments were applied to identify Ulk1 as a substrate of Smurf1. Further, we constructed the cell and animal models with silencing or overexpression of Smurf1 and Ulk1 to clarify the potential mechanism of Smurf1 on ferroptosis in ALF. Knockdown or overexpression of Smurf1 promoted or inhibited hepatocyte ferroptosis, respectively. In the animal model, knockdown of Smurf1 significantly aggravated the progression of ALF, suggesting that Smurf1 knockdown exacerbated liver failure by promoting hepatocyte ferroptosis. In conclusion, Smurf1 interacted with the new substrate Ulk1 and promoted its ubiquitin-mediated degradation at the post-translational level, and Smurf1 knockdown promotes ferroptosis in hepatocytes in a manner dependent on Ulk1-mediated autophagy activation.