Proanthocyanidins alleviate acute alcohol liver injury by inhibiting pyroptosis via inhibiting the ROS-MLKL-CTSB-NLRP3 pathway.

BACKGROUND

Alcoholic Liver Disease (ALD) is a hepatic disorder resulting from prolonged or excessive alcohol intake. The predominant manifestation of ALD is fatty liver, which progresses to alcoholic hepatitis as the disease worsens. Pyroptosis is a novel type of programmed cell death that is intricately linked to the inflammatory cascade, presenting a promising avenue for therapeutic intervention in the management of ALD. Oligomeric proanthocyanidins (OPCs) are polyphenols extracted from grape seeds that have anti-inflammatory and antioxidant properties. However, whether OPCs can treat ALD by suppressing pyroptosis is not completely clarified.

PURPOSE: To explore the role of OPCs in ALD to inhibit pyroptosis and its mechanism.

METHODS

In vitro, HepG2 cells were employed to evaluate the beneficial impact of OPCs on alcohol-induced pyroptosis. MTT colorimetric method, enzyme-linked immunosorbent assay (ELISA), western blot (WB), immunofluorescence, acridine orange (AO) staining, and reactive oxygen species (ROS) assay were performed. In vivo, C57BL mice were used and gavaged with alcohol and OPCs. Hematoxylin-eosin staining (HE) staining, alanine aminotransferase (ALT), aspartate aminotransferase (AST) level assay, and WB were performed.

RESULTS

The findings revealed that OPCs could reduce the alcohol-induced increase in pyroptosis-related proteins, such as pyrin domain-containing 3 protein (NLRP3), cleaved-caspase 1, gasdermin D (GSDMD-N), Interleukin-18 (IL-18), IL-1β (IL-1β). In in vitro mechanistic experiments, We discovered that OPCs ameliorate alcohol-induced pyroptosis by decreasing cathepsin B (CTSB) leakage-mediated NLRP3 activation. More significantly, we discovered that alcohol phosphorylates mixed lineage kinase domain-like protein (MLKL), enabling P-MLKL to translocate to the lysosomal membrane and induce lysosomal membrane permeabilization (LMP). OPCs might counteract the effects of alcohol by reducing the leakage of CTSB and inhibiting the phosphorylation of MLKL through the scavenging of ROS.

CONCLUSIONS

These results suggested that OPCs might counteract ALD by inhibiting pyroptosis through the ROS-MLKL-CTSB-NLRP3 pathway. Our study offered fresh insight into the ways in which naturally occurring chemicals shield ALD against harm.