FUNDC1 interacts with GPx4 to govern hepatic ferroptosis and fibrotic injury through a mitophagy-dependent manner

Introduction

Liver fibrosis is a life-threatening pathological anomaly which usually evolves into advanced liver cirrhosis and hepatocellular carcinoma although limited therapeutic option is readily available. FUN14 domain containing 1 (FUNDC1) is a mitophagy receptor with little information in liver fibrosis.

Objective

This study was designed to examine the role for FUNDC1 in carbon tetrachloride (CCl4)-induced liver injury.

Methods

GEO database analysis and subsequent validation of biological processes including western blot, immunofluorescence, and co-immunoprecipitation were applied to clarify the regulatory role of FUNDC1 on mitophagy and ferroptosis.

Results

Our data revealed elevated FUNDC1 levels in liver tissues of patients with liver fibrotic injury and CCl4-challenged mice. FUNDC1 deletion protected against CCl4-induced hepatic anomalies in mice. Moreover, FUNDC1 deletion ameliorated CCl4-induced ferroptosis in vivo and in vitro. Mechanically, FUNDC1 interacted with glutathione peroxidase (GPx4), a selenoenzyme to neutralize lipid hydroperoxides and ferroptosis, via its 96–133 amino acid domain to facilitate GPx4 recruitment into mitochondria from cytoplasm. GPx4 entered mitochondria through mitochondrial protein import system-the translocase of outer membrane/translocase of inner membrane (TOM/TIM) complex, prior to degradation of GPx4 mainly through mitophagy along with ROS-induced damaged mitochondria, resulting in hepatocyte ferroptosis.

Conclusion

Taken together, our data favored that FUNDC1 promoted hepatocyte injury through GPx4 binding to facilitate its mitochondrial translocation through TOM/TIM complex, where GPx4 was degraded by mitophagy to trigger ferroptosis. Targeting FUNDC1 may be a promising therapeutic approach for liver fibrosis.