WITHDRAWN: The cell fate determinant NUMB regulates ferroptosis through interacting with P53/MFRN1 signaling

Abstract

Abstract Ferroptosis is a kind of programmed cell necrosis accompanied by iron-dependent lipid peroxidation, but its regulatory mechanisms are largely unknown. In the present study, we showed that the cell fate determinant NUMB may regulate ferroptosis through interacting with P53/MFRN1 signaling in hepatic stellate cells (HSCs). Upon exposure to ferroptosis-inducing compounds, the expression of NUMB protein was evidently elevated through the inhibition of the ubiquitin-proteasome pathway. The knockout of NUMB led to ferroptosis resistance, whereas the overexpression of NUMB promoted HSC ferroptosis. Intriguingly, increased NUMB appeared to trigger the mitochondrial translocation of p53 protein via binding to its N-terminal transactivation domain. Site-directed mutations of serine 392 evidently impaired the binding of NUMB to p53, blocked the mitochondrial translocation of p53 protein, and prevented NUMB-enhanced HSC ferroptosis. Importantly, mitochondrial p53 could interact with mitoferrin-1 (MFRN1) to increase the activity of MFRN1, which may result in the overload of mitochondrial iron and the hyperfunction of electron transfer chain (ETC). Attractively, the knockdown of MFRN1 could damage NUMB- or p53-mediated HSC ferroptosis. In mice, treatment with erastin alleviated murine liver fibrosis by inducing HSC ferroptosis. HSC-specific blockade of NUMB/P53/MFRN1 signaling abrogated erastin-enhanced HSC ferroptosis. Noteworthy, we determined the impact of sorafenib on HSC ferroptosis in advanced fibrotic patients with hepatocellular carcinoma receiving sorafenib monotherapy. As expected, the upregulation of NUMB protein, the mitochondrial translocation of p53, the bind of p53 to MFRN1, mitochondrial iron accumulation, ETC hyperfunction, lipid peroxidation, and ferroptosis induction occurred in human HSCs. Overall, these results revealed novel molecular mechanisms and signaling pathways of ferroptosis, and further suggest NUMB/P53/MFRN1 signaling as potential targets for fibrotic diseases.