Ursocholic Acid Ameliorates Hepatic Steatosis via Direct AMPK Activation in Preclinical Models of MASLD

Ursocholic acid (UCA) alleviates experimental metabolic dysfunction-associated steatotic liver disease (MASLD) by reducing hepatic lipid accumulation in vitro and in vivo. • UCA is a natural AMPK agonist that inhibits key lipogenic genes, ameliorating hepatic lipid metabolism imbalances. • UCA exhibits dose-proportional pharmacokinetics and preferential hepatic distribution, with a half-life comparable to UDCA. • Preferential hepatic distribution and direct AMPK binding may concentrate pharmacological effects in the liver, potentially reducing systemic off-target risks. Background Metabolic dysfunction-associated steatotic liver disease (MASLD) is a major global health challenge lacking effective therapeutic agents. Ursocholic acid (UCA), a natural bile acid with established cholesterol-lowering properties, has not been evaluated for MASLD treatment. Objective To investigate the therapeutic efficacy, mechanism of action, and pharmacokinetic profile of UCA in MASLD. Methods Hepatoprotective effects were assessed in free fatty acid (FFA)-induced Huh7 cells and high-fat diet (HFD)-fed mice. RNA sequencing identified target pathways. Direct AMPK interaction was validated by molecular docking, molecular dynamics simulation, and cellular thermal shift assay. Pharmacokinetics were compared with ursodeoxycholic acid (UDCA). Results UCA dose-dependently reduced hepatic lipid accumulation in vitro and in vivo . Transcriptomic analysis revealed AMPK signaling as the primary modulated pathway. Mechanistically, UCA directly bound to AMPK, promoted Thr172 phosphorylation, and downregulated lipogenic genes ( SREBF1 , LPIN1 , FASN , SCD1 ), and these effects were abrogated by Compound C (AMPK inhibitor). Pharmacokinetically, UCA exhibited dose-proportional oral exposure (AUC last 1,120–13,700 h·ng/mL across 30–300 mg/kg) with a terminal half-life of 3.7–5.9 hours, comparable to UDCA. Conclusion UCA is a direct AMPK agonist that ameliorates MASLD by suppressing the SREBF1/LPIN1 lipogenic axis, representing a promising natural therapeutic candidate. Download: Download high-res image (118KB) Download: Download full-size image