Discovery of 7-ether substituted homoisoflavonoids as selective FXR modulators attenuating MASH via the FXR and AMPK...

Farnesoid X receptor (FXR) modulation represents a promising therapeutic strategy for metabolic dysfunction-associated steatohepatitis (MASH, formerly NASH); however, the development of MASH drugs from FXR full and partial agonists remains unsucessful. In this study, we employed ring cyclization of our previously identified chalcone FXR antagonists to homoisoflavonoid skeleton and to which attached various 7-ester and ether substituents. Among them, 4l was identified as most potent compound exhibiting high binding affinity and potent cellular antagonistic activity with an IC₅₀ value of 0.70 μM. Molecular docking analysis revealed that the high affinity of 4l is driven by a T-shaped π-π stacking interaction and a robust hydrogen bond network within the FXR binding pocket. Further characterization revealed it functions as a highly selective FXR modulator by regulating the expression of downstream genes responsible for bile acid and lipid transporters (SHP, BSEP, SREBP-1c, and CYP7A1)-while sparing key gluconeogenic genes (PEPCK and G6Pase). In a CDA-HFD-induced MASH mouse model, oral administration of 4l significantly ameliorated hepatic steatosis, ballooning degeneration, and fibrosis, and dyslipidemia. Mechanistic studies further demonstrated that 4l exerts its lipid-lowering effects by activating the AMPK-ACC signaling pathway. Collectively, these findings highlight the 7-ether substituted homoisoflavonoid 4l as a novel, selective FXR modulator with significant therapeutic potential for the treatment of MASH.