Betulinic acid alleviates endoplasmic reticulum stress‐mediated nonalcoholic fatty liver disease through activation of farnesoid X receptors in mice

Abstract

Background and Purpose: The molecular mechanism for the pathogenesis of nonalcoholic fatty liver disease (NAFLD) remains elusive. Both farnesoid X receptor (FXR) signalling and endoplasmic reticulum (ER) stress contribute to the progression of NAFLD; however, it is not clear whether the actions of these two pathways are dependent on each other. Moreover, the pharmacological benefits and mechanism of betulinic acid (BA) in controlling metabolic syndrome and NAFLD are largely unknown.Experimental Approach: A reporter assay and a time-resolved FRET assay were used to identify BA as an agonist of the FXR. NAFLD was induced by a methionine and choline-deficient L-amino acid diet (MCD) and high-fat diet (HFD). The pharmacological effects of BA (100 mg·kg −1 ·day −1 ) and potential interactions between hepatic FXR activation and ER stress pathways were evaluated by FXR silencing, Western blot and RT-PCR analyses using control and FXR −/− mice.Key Results: Activation of the FXR inhibited intracellular PERK/EIF2α/ATF4 and CHOP signalling, thereby alleviating hepatic ER stress, whereas FXR silencing resulted in an opposite effect. Furthermore, we identified BA as an FXR agonist that effectively attenuated the progression of NAFLD and metabolic disorders in both HFD-and MCD diet-fed mice and restored the hepatocellular ER homeostasis by stimulating the FXR signalling pathway and blocking PERK/EIF2α signalling. In contrast, the effects of BA were attenuated in FXR −/− mice. Conclusions and Implications:Our data demonstrate that pharmacological activation of the FXR by BA reduces hepatocellular ER stress and attenuates NAFLD in an animal model of hepatic steatosis.

Betulinic acid improves nonalcoholic fatty liver disease through YY1/FAS signaling pathway

“…ER stress, is a phenotypic hallmark in many liver diseases, including NAFLD 45,46 . Our data showed that BA also had a strong resistance to ER stress (Figures S2‐S5), which was in accordance with another group 47 . BA can alleviate the occurrence and progression of liver fibrosis and is expected to become a novel anti‐fibrosis drug to prevent NASH.…”

“…45,46 Our data showed that BA also had a strong resistance to ER stress ( Figures S2-S5), which was in accordance with another group. 47 BA can alleviate the occurrence and progression of liver fibrosis and is expected to become a novel anti-fibrosis drug to prevent NASH. This might provide a new direction for the relationship between BA and NAFLD.…”

Herbal Medicine in the Treatment of Non-Alcoholic Fatty Liver Diseases-Efficacy, Action Mechanism, and Clinical Application

“…Endoplasmic Reticulum (ER) Stress ER stress involved the increase of JNK and caspase-12 expression serves a primary role in the procession of NAFLD and pathogenesis to NASH. The pharmacological activation of FXR induced by betulinic acid alleviated the hepatic ER stressmediated hepatic steatosis (Gu et al, 2019). The farnesoid X receptor (FXR) activation suppresses the expression of ER stress markers (PERK, EIF2a and ATF4) and CHOP signaling, thereby reducing hepatocellular ER stress.…”

Effect of Fermented Corn-Soybean Meal on Serum Immunity, the Expression of Genes Related to Gut Immunity, Gut Microbiota, and Bacterial Metabolites in Grower-Finisher Pigs

“…Many studies have highlighted the correlation between gut microbiota and intestinal morphology, regulation of immunity, digestion of carbohydrates, and body health in livestock (Richards et al, 2005; Stanley et al, 2016; Gu et al, 2019; Guevarra et al, 2019). Recent evidence suggests that the gut microbiota plays a crucial role in livestock health and disease (Tremaroli and Backhed, 2012).…”