Oridonin Ameliorates Metabolic-Dysfunction-Associated Fatty Liver Disease by Inhibiting PANoptosis via Modulating SIRT2/NLRP3 Pathway

Metabolic associated fatty liver disease (MAFLD) is the leading cause of chronic liver disease worldwide. Various studies have demonstrated that traditional Chinese medicine alleviates MAFLD by suppressing PANoptosis. Although Oridonin (ORI) is a traditional Chinese medicine that has been used in hepatosteatosis, its underlying mechanism for treating MAFLD, especially regarding PANoptosis, remains unclear. Therefore, this study aims to investigate the ameliorative effects of ORI on MAFLD by inhibiting PANoptosis and to elucidate the underlying mechanisms. A vivo model of MAFLD was constructed by feeding mice with a high-fat diet (HFD) for 12 weeks. ORI was simultaneously intragastric gavaged for 12 weeks. A vitro model of MAFLD was constructed by palmitic acid (PA) induced AML12 cells for 24 h; ORI was simultaneously induced for 24 h. Extraction of mice plasma for detecting lipid-related and oxidative stress-related assay kits was performed. Lipid metabolism and PANoptosis-related proteins and pathways were validated both in vivo and in vitro through western blotting and immunofluorescence. The functions of the candidate proteins were further investigated using the plasmid transfection technique. Then the Biotin labeling assays were used to analyze the proteins' direct interaction with ORI. ORI treatment significantly alleviated HFD-induced inflammation and PANoptosis. Likewise, ORI effectively attenuated PANoptosis induced by PA in the AML12 cells. Additionally, over-expression of NLRP3, which is a key component in PANoptosis, could partly antagonize the inhibiting effects of ORI on steatosis and PANoptosis. Next, our findings demonstrated the increased NLRP3 acetylation level in PA-induced cells, while ORI treatment decreased the NLRP3 acetylation level. Further studies revealed that ORI could bind to and activate SIRT2 to increase the protein expression and stability of SIRT2, which in turn deacetylated and inactivated NLRP3. Moreover, over-expression of NLRP3 could partly antagonize the inhibiting effects of ORI on lipid droplet deposition and PANoptosis, which could be rescued by over-expression of SIRT2. Therefore, these findings show that ORI can alleviate MAFLD by suppressing PANoptosis via inhibiting the SIRT2/NLRP3 pathway. These findings provide new therapeutic targets and mechanisms for the treatment of MAFLD.

NLRP3; Oridonin; PANoptosis; SIRT2; metabolic associated fatty liver disease; post‐translational modifications.