A single-cell atlas of the woodchuck liver reveals cellular programs conserved in human HBV infection.

Abstract

BACKGROUND & AIMS: The eastern woodchuck (Marmota monax), which can be naturally infected with woodchuck hepatitis virus (WHV), has served as a model for studying aspects of human HBV infection, including the establishment of chronic infection and progression from chronic hepatitis to liver cancer. However, the cellular landscape of the woodchuck liver and its parallels to HBV infection remain uncharacterized. METHODS: We generated a single-cell and spatial transcriptomic atlas of the woodchuck liver in health and chronic WHV infection, characterizing cell types and infection-associated processes in hepatic tissue (healthy: 52,024 cells; infected: 40,810 cells; n = 8 per group) and peripheral blood mononuclear cells (healthy: 25,314 cells, n = 7; infected: 19,518 cells, n = 8). We further examined shared WHV-HBV disease pathways transcriptionally and assessed woodchuck liver immune responses functionally using PCLS (precision-cut liver slice) stimulation. RESULTS: Using this atlas, we found that hepatic cellular and immune diversity in the woodchuck liver is comparable to that of human livers. Immune cells in PMA/ionomycin-stimulated PCLS exhibited a robust type I inflammatory response, as expected, supporting the accuracy of our cell-type annotations. Our atlas further revealed transcriptional and cellular similarities between WHV- and HBV-infected livers, including periportal dendritic cell activation and a restructuring of the T-cell compartment from memory toward exhaustion during WHV infection, a hallmark of chronic human HBV. CONCLUSIONS: We present a multi-omic atlas of healthy, diseased, and ex vivo-stimulated woodchuck liver. This work identified shared WHV-HBV pathological processes, reinforces the value of this preclinical model, and provides a resource to advance HBV pathogenesis studies and therapeutic development. IMPACT AND IMPLICATIONS: Limited treatment options for liver disease, often culminating in the need for liver transplantation, underscore the requirement for human-relevant animal models to speed up the development of new therapeutic interventions. Woodchucks infected with woodchuck hepatitis virus develop chronic hepatitis and liver cancer, mirroring human HBV infection. However, the cellular composition and active biological processes within the woodchuck liver have remained poorly understood, limiting the model's utility for therapeutic discovery. In this study, we characterize the healthy and chronically infected woodchuck liver at single-cell resolution and compare it with human HBV infection, thereby reinforcing the value of the WHV-infected woodchuck as a model for human HBV disease.