Losing β-Catenin in the Liver Protects Mice From Toxic Bile Acid Injury

Researchers led by Kari Nejak-Bowen found that mice engineered to lack β-catenin specifically in their hepatocytes suffered far less liver injury than normal littermates when fed a diet containing 0.6% lithocholic acid for seven days. The knockout animals developed fewer and smaller bile infarcts, the patches of dead tissue that form when hydrophobic bile acids accumulate and poison hepatocytes, and showed measurably less hepatobiliary injury overall. Lithocholic acid is a hydrophobic bile acid associated with adverse clinical outcomes in primary sclerosing cholangitis, a disease in which retention of toxic bile acids leads to cell death, inflammation, and fibrosis.

The team hypothesized that removing β-catenin, a protein they had previously linked to bile acid accumulation, might blunt this toxicity. Their new results confirm the idea and reveal the mechanisms behind it, pointing to a β-catenin-dependent pathway that contributes to cholestatic damage. The first protective mechanism involves detoxification.

In the absence of β-catenin, xenobiotic defense pathways that chemically neutralize bile acids were strongly activated. The pregnane X receptor, a nuclear sensor of foreign compounds, became more active and drove up expression of detoxification genes such as Cyp3a11 and Cyp2b10, which modify bile acids into less harmful forms. As a result, the bile acids circulating in the knockout mice's serum were less hydrophobic, and therefore less destructive to cell membranes, than those in the wild-type animals.

The second mechanism centers on cholesterol handling. Normally, lithocholic acid activates the pregnane X receptor while simultaneously blocking HNF4 from binding the Cyp7a1 promoter, which suppresses bile acid synthesis and allows cholesterol to pile up in hepatocytes. Without β-catenin, however, HNF4 binding to the Cyp27a1 promoter increased, steering metabolism toward the production of more hydrophilic bile acids and toward oxysterols, oxidized cholesterol derivatives.

These oxysterols then activated the liver X receptor, or LXR, a master regulator of cholesterol homeostasis. Once switched on, LXR repressed cholesterol synthesis while boosting genes that export cholesterol and oxysterols out of hepatocytes, easing the intracellular burden. The researchers also observed that LXR activation dampened inflammatory gene expression in Kupffer cells, the liver's resident macrophages, adding an anti-inflammatory layer to the metabolic protection.

Inflammation itself was reshaped in a third, unexpected way. Hepatocytes lacking β-catenin produced less IL-33, an alarmin cytokine released by damaged cells. Lower IL-33 meant reduced recruitment of type 2 innate lymphoid cells, immune cells known to worsen cholestatic disease.

The knockout livers therefore mounted a milder inflammatory response, which the authors link directly to the reduced tissue damage seen under the microscope. Taken together, the findings describe a newly identified β-catenin-dependent mechanism of hepatic injury in cholestasis: the protein's presence appears to limit the liver's own detoxification and cholesterol-export machinery while amplifying a damaging immune signal. Its loss, at least in this experimental setting, simultaneously improves bile acid composition, cholesterol metabolism, and inflammatory signaling.

The study carries important caveats. It was conducted in mice exposed to a lithocholic acid diet for one week, a model of acute cholestatic stress rather than the years-long course of human primary sclerosing cholangitis. Even so, the convergence of bile acid detoxification, LXR-driven cholesterol efflux, and IL-33–dependent immune recruitment into a single regulatory axis gives researchers a defined picture of how toxic bile accumulation injures the liver and how its composition, metabolism, and inflammatory signaling can shift together when β-catenin is absent.

Subject of Research: Loss of β-catenin improves cholestatic injury through activation of bile acid detoxification and cholesterol metabolism

Article Title: Loss of β-catenin improves cholestatic injury through activation of bile acid detoxification and cholesterol metabolism

Article References: Goel, C., Carson, M., Drda, J., Case, R., Maloy, A., Zhang, R., Liu, S., Locker, J., Cornuet, P., Qin, F.-Y., Molina, L., Ma, X., & Nejak-Bowen, K. (2026). Loss of β-catenin improves cholestatic injury through activation of bile acid detoxification and cholesterol metabolism. Cellular and Molecular Life Sciences. https://doi.org/10.1007/s00018-026-06503-8

Image Credits: AI Generated

DOI: 10.1007/s00018-026-06503-8

Keywords: Loss, catenin, improves, cholestatic, injury, activation, bile, acid, detoxification, cholesterol, metabolism, scientific research