Single-nucleus RNA sequencing reveals HBV-driven metabolic reprogramming and TIMP1-mediated fibrosis in human-liver-chimeric mice

Introduction: Hepatitis B virus (HBV) infection remains a leading cause of chronic liver disease, cirrhosis, and hepatocellular carcinoma worldwide. Despite advances in antiviral therapies, the mechanisms underlying HBV-induced metabolic reprogramming and liver fibrosis remain poorly understood. Methods: We employed single-nucleus RNA sequencing (snRNA-seq) which is particularly suitable for hepatocytic sequencing to dissect the transcriptional landscape of HBV-infected and uninfected hepatocytes in humanized URG mice (Hu-URG). Results and Discussion: Chronic HBV infection was successfully established in Hu-URG mice, with progressive increases in serum HBV DNA, HBsAg, and HBeAg levels. snRNA-seq revealed distinct human hepatocyte clusters (clusters 9, 16, 23) characterizing elevated expression of metabolic genes (ALB, UGT2B17, CYP2A6) in HBV-infected cells, while HBV-uninfected cells exhibited upregulation of TIMP1 and pro-fibrotic pathways. Immunofluorescence and histological analyses confirmed that HBV-uninfected hepatocytes (HBsAg^-) displayed higher TIMP1 expression and reduced albumin (hALB) levels, correlating with increased collagen deposition in HBV-hu-URG mice. Notably, this TIMP1⁺HBsAg^-hALB^low phenotype was also observed in liver biopsies from chronic HBV patients, underscoring its clinical relevance. Our findings highlight HBV-driven metabolic adaptation and identify TIMP1 as a potential mediator of fibrosis in uninfected hepatocytes, offering novel insights into HBV pathogenesis and therapeutic targeting.