Atractylenolide I Alleviates Lipotoxicity in Hepatocytes and Protects NAFLD in Mice Through SIRT1 ‐Dependent IRE1α ‐ XBP1 Pathway

ABSTRACT Atractylenolide I (AO‐I), a major pharmacological ingredient derived from Atractylodes macrocephala , has been reported to possess multiple bioactivities. This study aimed to investigate the potential protective effects of AO‐I against lipotoxicity in both cultured hepatocytes and mice with non‐alcoholic fatty liver disease (NAFLD). The NAFLD model was established by feeding C57BL/6 mice a high‐fat diet (HFD) for 12 weeks. Oral administration of AO‐I at doses of 20 or 50 mg/kg body weight per day was explored. Lipotoxicity in AML12 hepatocytes was induced by incubation with palmitate for in vitro investigations on the roles of AO‐I. The results demonstrated that supplementation with AO‐I improved alanine transaminase (ALT), aspartate transaminase (AST), and liver histology in NAFLD mice. Furthermore, AO‐I directly alleviated palmitate‐induced lipotoxicity by reducing hepatocyte death. Mechanistic studies revealed that AO‐I significantly attenuated lipotoxicity through its potential resistance to endoplasmic reticulum (ER) stress and IRE1α‐XBP1 splicing both in vivo and in vitro. We identified that AO‐I substantially rescued HFD‐ and palmitate‐induced SIRT1 decline in mouse livers and hepatocytes, respectively, thereby improving liver injury and hepatocyte cell death. Mechanistic studies demonstrated that the amelioration of ER stress and lipotoxicity by AO‐I supplementation depended on SIRT1 activity. Moreover, AO‐I also mitigated IRE1α activation‐triggered JNK/p38 MAPK hyperphosphorylation. In conclusion, our findings suggest that AO‐I exhibits significant therapeutic effects for improving lipotoxicity in the liver and may be considered as a candidate for NAFLD therapy.