Alisol B 23-Acetate Down-Regulated GRP94 to Restore Endoplasmic Reticulum Homeostasis on Non-Alcoholic...

Non-alcoholic steatohepatitis (NASH) poses a serious threat to human health. Alisol B 23-Acetate (AB23A) has shown beneficial effects on NASH, but its mechanism of action remains unclear. We conducted in vitro experiments by inducing L02 cell damage with free fatty acids (FFA) and administering various concentrations of AB23A. We found that AB23A intervention reduced triglyceride (TG) levels in FFA-induced L02 cells and improved cellular steatosis. Transcriptomic analysis revealed that AB23A intervention significantly downregulated glucose-regulated protein 94 (Grp94), indicating that AB23A primarily regulates the protein processing pathway in the endoplasmic reticulum. Within this pathway, AB23A intervention also significantly downregulated endoplasmic reticulum stress (ERS)-related genes (PERK, eIF2α, ATF4) and ER-associated degradation (ERAD)-related genes (FBXO2, DERL, HSP90AA1). When we silenced GRP94, the regulatory effects of AB23A on TG levels, cellular steatosis, ERS-related proteins (p-PERK/PERK, p-eIF2α/eIF2α, ATF4), and ERAD-related proteins (FBXO2, DERL, HSP90α) disappeared. In vivo, AB23A intervention promoted recovery of the liver index in NASH mice, reduced hepatic inflammatory infiltration and lipid deposition, improved serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities, and reduced liver TG levels. RT-qPCR and Western blot results demonstrated that AB23A intervention dose-dependently downregulated the gene and protein expression of GRP94 and ERS- and ERAD-related factors. There was no significant difference between the effects of high-dose AB23A intervention and PPC intervention. This study demonstrated, through both in vitro and in vivo experiments, that AB23A improves hepatic steatosis. This effect may be related to the downregulation of GRP94, which suppresses ERS and ERAD, thereby restoring ER homeostasis.