Human PXR Signaling Exacerbates Ethanol-induced Liver Injury in Females: Evidence From Mouse Models and Human Alcohol-associated Liver Disease Cohorts

Abstract

Background & aims: Alcohol-associated liver disease (ALD), resulting from excessive alcohol consumption, manifests with greater severity in females. The pregnane X receptor (PXR), a xenobiotic nuclear receptor critical for toxin defense, has been implicated in ALD; however, the mechanisms underlying its role, particularly in sex differences, remain unclear. Due to species-specific ligand differences, PXR-humanized (hPXR) mouse models are essential for investigating PXR's contribution to sexual dimorphism in human ALD. Methods: Male and female C57BL/6N Tac wild-type (WT) and hPXR mice were subjected to the 10-day chronic-plus-binge ethanol (NIAAA) model. Assessments included hepatotoxicity, liver histopathology, protein expression, hepatic transcriptomics, and bioinformatic analyses. Complementary gene expression and tissue microarray (TMA) analyses were performed on human ALD liver samples. Results: Ethanol-induced hepatotoxicity was most pronounced in female hPXR mice. Microarray profiling identified 442 genes uniquely regulated by ethanol in female hPXR mice, highlighting significant pathway alterations. Quantitative analyses revealed that hepatotoxicity correlated with increased hepatic mRNA levels of Pparg (1.9-fold), its target Fsp27/Cidec (31-fold), liver-specific Fsp27β (66-fold), and the CAR/PXR target Cyp2b10, all implicated in ethanol-induced liver injury. Proinflammatory markers Tnfrsf12a (2.7-fold) and Fgf21 (14.6-fold) were also elevated. In female patients with ALD, hepatic mRNA levels of CIDEC (13.8-fold), CYP2B6 (the human ortholog of Cyp2b10, 3.7-fold), FGF21 (4.5-fold), and TNFRSF12A (3-fold) were significantly increased. TMA analyses further demonstrated elevated expression of CYP2B6 and PXR1 in patients with alcohol-associated hepatitis. Conclusions: These data indicate that hPXR-transgenic mice serve as a valuable in vivo model to elucidate mechanisms driving sexual dimorphism in ethanol-induced hepatotoxicity.