Axin formation inhibitor 1 aggravates hepatic ischemia‒reperfusion injury by promoting the ubiquitination and degradation of PPARβ.

Hepatic ischemia‒reperfusion injury (HIRI) is a common pathological phenomenon after hepatectomy and liver transplantation. Here, we aim to explore the role of Axin formation inhibitor 1 (Axin1) in HIRI. In this work, we find that the expression of Axin1 is upregulated after HIRI. Cellular experiments confirme that Axin1 knockdown alleviated hypoxia/reoxygenation (H/R)-induced inflammation and apoptosis. Subsequently, we construct a HIRI model based on transgenic hepatocellular-specific Axin1 knockout and overexpression male mice and find that Axin1 deletion alleviated inflammation and apoptosis. Transcriptome sequencing reveal that the genes whose expression differed after Axin1 overexpression are significantly enriched in the PPAR signaling pathway. Furthermore, we demonstrate that Axin1 negatively regulates the expression of PPARβ, thereby activating the NF-κB pathway. Mechanistically, Axin1 binds to PPARβ to enhance the ubiquitination-mediated degradation of PPARβ by the E3 ubiquitin ligase RBBP6. Notably, adenovirus-mediated Axin1 knockdown block I/R damage in mice. Our study results demonstrate that Axin1 exacerbates HIRI by promoting the ubiquitination and degradation of PPARβ, which in turn activates the NF-κB signaling pathway. These results suggest that Axin1 may be a potential therapeutic target for HIRI.