Activation of intestinal endogenous retroviruses by alcohol exacerbates liver disease
Noemí Cabré, … , Peter Stärkel, Bernd Schnabl
Noemí Cabré, … , Peter Stärkel, Bernd Schnabl
Published May 13, 2025
Citation Information: J Clin Invest. 2025;135(13):e188541. https://doi.org/10.1172/JCI188541.
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Research Article Gastroenterology Hepatology

Activation of intestinal endogenous retroviruses by alcohol exacerbates liver disease

Abstract

Alcohol-associated liver disease represents a significant global health challenge, with gut microbial dysbiosis and bacterial translocation playing a critical role in its pathogenesis. Patients with alcohol-associated hepatitis had increased fecal abundance of mammalian viruses, including retroviruses. This study investigated the role of endogenous retroviruses (ERVs) in the development of alcohol-associated liver disease. Transcriptomic analysis of duodenal and liver biopsies revealed increased expression of several human ERVs, including HERV-K and HERV-H, in patients with alcohol-associated liver disease compared with individuals acting as controls. Chronic-binge ethanol feeding markedly induced ERV abundance in intestinal epithelial cells but not the livers of mice. Ethanol increased ERV expression and activated the Z-DNA binding protein 1 (Zbp1)–mixed lineage kinase domain-like pseudokinase (Mlkl) signaling pathways to induce necroptosis in intestinal epithelial cells. Antiretroviral treatment reduced ethanol-induced intestinal ERV expression, stabilized the gut barrier, and decreased liver disease in microbiota-humanized mice. Furthermore, mice with an intestine-specific deletion of Zbp1 were protected against bacterial translocation and ethanol-induced steatohepatitis. These findings indicate that ethanol exploits this pathway by inducing ERVs and promoting innate immune responses, which results in the death of intestinal epithelial cells, gut barrier dysfunction, and liver disease. Targeting the ERV/Zbp1 pathway may offer new therapies for patients with alcohol-associated liver disease.

Authors

Noemí Cabré, Marcos F. Fondevila, Wenchao Wei, Tomoo Yamazaki, Fernanda Raya Tonetti, Alvaro Eguileor, Ricard Garcia-Carbonell, Abraham S. Meijnikman, Yukiko Miyamoto, Susan Mayo, Yanhan Wang, Xinlian Zhang, Thorsten Trimbuch, Seija Lehnardt, Lars Eckmann, Derrick E. Fouts, Cristina Llorente, Hidekazu Tsukamoto, Peter Stärkel, Bernd Schnabl

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Figure 2

Ethanol activates Zbp1 and induces Mlkl-mediated necroptosis in intestinal epithelial cells.

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Ethanol activates Zbp1 and induces Mlkl-mediated necroptosis in intestin...
(A) Germ-free C57BL/6 mice were colonized with fecal microbiota from patients with alcohol-associated hepatitis (AH) and fed oral isocaloric (control) or chronic-binge ethanol diets. (B) Intestinal and hepatic levels of mouse mammary tumor virus (MMTV) env and gag mRNA. (C) Level of Zbp1 mRNA in the ileum. (D) Intestinal epithelial cells were isolated from ethanol-fed mice, and immunoblots were performed for phospho-Mlkl, Mlkl, Zbp1, and Gapdh; protein amounts of Zbp1 relative to Gapdh and protein amounts of phospho-Mlkl relative to Mlkl are shown (n = 5 control, n = 6 ethanol). (E–J) Mouse intestinal organoids were incubated with ethanol (0, 10, 20, and 50 mM) for 24 hours. (E) Expression levels of MMTV env and gag mRNA. (F) Expression level of Zbp1 mRNA. (G) Immunoblots of phospho-Mlkl, Mlkl, and Gapdh; protein amounts of phospho-Mlkl relative to Mlkl are shown (n = 5 in each group). (H) Immunoblot analysis of Mlkl in cytoplasmic and membrane extracts. Nonreducing and reducing SDS-PAGE were used to detect oligomerized and total Mlkl forms, respectively. (I) Representative images of intestinal organoids before and after treatment with ethanol (50 mM). (J) Lactate dehydrogenase (LDH) assay of supernatants was performed to measure cytotoxicity. Results were generated from 3 (B) or 2 (C–J) technical replicates. P values among groups were determined by Mann-Whitney U test (B–D) or 1-way ANOVA with Tukey’s post hoc test (E–G and J). Results are expressed as mean ± SEM. FMT, fecal microbiota transplantation. *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001. AU, arbitrary units.