Embelin improves alcoholic steatohepatitis in alcohol-associated liver disease via ATF6-mediated P2X7r-NLRP3 signaling pathway

Abstract

Background

Alcohol-associated liver disease (ALD) manifests with impaired lipid metabolism and inflammation within the liver. Embelin (EB), a natural para-benzoquinone compound derived from the Embelia ribes Burm.f. has several pharmacological properties.

Objective

This research examines how EB influences the inflammatory milieu of the liver in ALD.

Methods

In vivo, we created an ALD model by subjecting mice to the Lieber–DeCarli diet for ten days, supplemented by a solitary binge, and subsequent ATF6 silencing. We employed RNA sequencing to analyze the ALD-related signaling pathways. In vitro experiments involved treating AML12 with EB and ethanol, and administering a siRNA-ATF6 to HepG2 cells. We investigated the ATF6 and P2 × 7r promoter interaction through a dual-luciferase assay. Mouse bone marrow-derived macrophages (BMDMs) were also treated with lipopolysaccharide/adenosine triphosphate (LPS/ATP) and EB to produce a conditioned medium.

Results

EB effectively mitigated lipid synthesis and the formation of neutrophil extracellular traps (NETs) during ALD. RNA sequencing revealed significant alterations in the ATF6/NOD-like receptor pathway in alcohol-induced mice. EB up-regulated ATF6 while down-regulating P2 × 7r-NLRP3 and its target genes. shRNA-mediated ATF6 knockdown markedly increased P2 × 7r protein and mRNA levels in mouse livers and exacerbated lipid accumulation. The absence of ATF6 in hepatocytes impaired the inhibitory effect of EB on the P2 × 7r-NLRP3 pathway. It was demonstrated that ATF6 directly binds to the P2 × 7r promoter. Moreover, EB reduced pyroptosis in BMDMs, thereby diminishing the inflammatory response.

Conclusions

These findings suggest that EB ameliorates alcoholic steatohepatitis (ASH) by modulating the ATF6-P2 × 7r/NLRP3 signaling pathway in ALD. EB might be a prospective therapeutic candidate, and its mechanism would be a new direction or strategy for alcoholic liver disease.