Clinical Implications of HBV PreS/S Mutations and the Effects of PreS2 Deletion on Mitochondria, Liver Fibrosis, and Cancer Development

• Published in: Hepatology (Baltimore, Md.) Vol. 74; no. 2; pp. 641 - 655
• Main Authors: Liang, Yuh‐Jin, Teng, Wei, Chen, Chih‐Li, Sun, Cheng‐Pu, Teng, Rui‐Dung, Huang, Yen‐Hua, Liang, Kung‐Hao, Chen, Yi‐Wen, Lin, Chung‐Chih, Su, Chien‐Wei, Tao, Mi‐Hua, Wu, Jaw‐Ching
• Format: Journal Article
• Language: English
• Published: United States Wiley Subscription Services, Inc 01.08.2021
• Subjects: Adult; Alanine; Alanine transaminase; Animals; Antiviral agents; Antiviral Agents - therapeutic use; Calcium (mitochondrial); Calcium (reticular); Carcinogenesis - immunology; Carcinoma, Hepatocellular - epidemiology; Carcinoma, Hepatocellular - immunology; Carcinoma, Hepatocellular - pathology; Carcinoma, Hepatocellular - virology; Case-Control Studies; Caspase; Deletion mutant; Deoxyribonucleic acid; Disease Models, Animal; DNA; Endoplasmic reticulum; Energy metabolism; Female; Fibrosis; Follow-Up Studies; Gene deletion; Hepatitis B; Hepatitis B surface antigen; Hepatitis B Surface Antigens - genetics; Hepatitis B Surface Antigens - immunology; Hepatitis B virus - genetics; Hepatitis B virus - immunology; Hepatitis B, Chronic - drug therapy; Hepatitis B, Chronic - immunology; Hepatitis B, Chronic - pathology; Hepatitis B, Chronic - virology; Hepatocytes - transplantation; Hepatology; Host-Pathogen Interactions - genetics; Humans; Liver; Liver cancer; Liver Cirrhosis - epidemiology; Liver Cirrhosis - immunology; Liver Cirrhosis - pathology; Liver Cirrhosis - virology; Liver diseases; Liver Neoplasms - epidemiology; Liver Neoplasms - immunology; Liver Neoplasms - pathology; Liver Neoplasms - virology; Longitudinal Studies; Male; Membrane potential; Mice; Mice, Knockout; Middle Aged; Mitochondria; Mitochondria, Liver - pathology; Multivariate analysis; Mutants; Mutation; Patients; Protein folding; Protein Precursors - genetics; Protein Precursors - immunology; RAG2 protein; Retrospective Studies; Transplantation Chimera; Ultrastructure
• ISSN: 0270-9139; 1527-3350
• DOI: 10.1002/hep.31789

Background and Aims PreS mutants of HBV have been reported to be associated with HCC. We conducted a longitudinal study of the role of HBV preS mutations in the development of HCC, particularly in patients with chronic hepatitis B (CHB) having low HBV DNA or alanine aminotransferase (ALT) levels, and investigated the effects of secretion‐defective preS2 deletion mutant (preS2ΔMT) on hepatocyte damage in vitro and liver fibrosis in vivo. Approach and Results Association of preS mutations with HCC in 343 patients with CHB was evaluated by a retrospective case–control follow‐up study. Effects of preS2ΔMT on HBsAg retention, endoplasmic reticulum (ER) stress, calcium accumulation, mitochondrial dysfunction, and liver fibrosis were examined. Multivariate analysis revealed a significant association of preS mutations with HCC (HR, 3.210; 95% CI, 1.072‐9.613; P = 0.037) including cases with low HBV DNA or ALT levels (HR, 2.790; 95% CI, 1.133‐6.873; P = 0.026). Antiviral therapy reduced HCC risk, including cases with preS mutations. PreS2ΔMT expression promoted HBsAg retention in the ER and unfolded protein response (UPR). Transmission electron microscopic examination, MitoTracker staining, real‐time ATP assay, and calcium staining of preS2ΔMT‐expressing cells revealed aberrant ER and mitochondrial ultrastructure, reduction of mitochondrial membrane potential and ATP production, and calcium overload. Serum HBV secretion levels were ~100‐fold lower in preS2ΔMT‐infected humanized Fah–/–/ Rag2–/–/Il2rg–/– triple knockout mice than in wild‐type HBV‐infected mice. PreS2ΔMT‐infected mice displayed up‐regulation of UPR and caspase‐3 and enhanced liver fibrosis. Conclusions PreS mutations were significantly associated with HCC development in patients with CHB, including those with low HBV DNA or ALT levels. Antiviral therapy reduced HCC occurrence in patients with CHB, including those with preS mutations. Intracellular accumulation of mutated HBsAg induced or promoted ER stress, calcium overload, mitochondrial dysfunction, impaired energy metabolism, liver fibrosis, and HCC.