title: In vivo proliferation of hepadnavirus-infected hepatocytes induces loss of covalently closed circular DNA in mice.
abstract: Chronic hepatitis B virus (HBV) infection is maintained by the presence of covalently closed circular DNA (cccDNA), the template of viral transcription and replication. In quiescent hepatocytes, cccDNA is a stable molecule that can persist throughout the hepatocyte lifespan. However, in chronic HBV infection, immunomediated cell injury and compensatory hepatocyte proliferation may favor cccDNA decline and selection of cccDNA-free cells. To investigate the impact of liver regeneration on cccDNA stability and activity in vivo, we used the urokinase-type plasminogen activator (uPA)/severe combined immunodeficiency (SCID) mouse model. Primary tupaia hepatocytes (PTHs) chronically infected with woolly monkey HBV (WM-HBV) were isolated from one highly viremic uPA/SCID chimeric mouse and transplanted into 20 uPA recipients. Expansion of transplanted PTHs and viral load changes were determined by real-time polymerase chain reaction and immunohistochemistry. Transplantation of WM-HBV infected hepatocytes led to an average of 3.8 PTH doublings within 80 days, 75% reduction of virion productivity (relaxed circular DNA/cccDNA), and lower expression levels of pregenomic RNA and hepatitis B core antigen. Remarkably, a median 2-log decline of cccDNA per cell determined during PTH proliferation was due to both dilution of the cccDNA pool among daughter cells and a 0.5-log loss of intrahepatic cccDNA loads (P = 0.02). Intrahepatic viral DNA sequences persisting at the end of the study were mostly present as replicative intermediates and not as integrated virus.
  
  
  CONCLUSIONS
  Cell division in the setting of liver regeneration and without administration of antiviral drugs induced strong destabilization of the cccDNA reservoir, resulting in cccDNA clearance in the great majority of chronically infected hepatocytes.
authors.affiliation: Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Marc
authors.initials: M
authors.lastname: Lutgehetmann
authors.forename: Tassilo
authors.initials: T
authors.lastname: Volz
authors.forename: Anne
authors.initials: A
authors.lastname: Köpke
authors.forename: Tim
authors.initials: T
authors.lastname: Broja
authors.forename: Eike
authors.initials: E
authors.lastname: Tigges
authors.forename: Ansgar W
authors.initials: AW
authors.lastname: Lohse
authors.forename: Eberhard
authors.initials: E
authors.lastname: Fuchs
authors.forename: John M
authors.initials: JM
authors.lastname: Murray
authors.forename: Joerg
authors.initials: J
authors.lastname: Petersen
authors.forename: Maura
authors.initials: M
authors.lastname: Dandri
mesh_terms: D000818:Animals; D049109:Cell Proliferation; D004270:DNA, Circular / Q000378:metabolism*; D004279:DNA, Viral / Q000378:metabolism*; D006515:Hepatitis B virus / Q000235:genetics / Q000502:physiology*; D019694:Hepatitis B, Chronic / Q000628:therapy / Q000821:virology*; D022781:Hepatocytes / Q000502:physiology / Q000637:transplantation / Q000821:virology*; D008115:Liver Regeneration; D051379:Mice; D016513:Mice, SCID; D014568:Urokinase-Type Plasminogen Activator / Q000235:genetics; D019562:Viral Load; D014779:Virus Replication
chemical_list: D004270:DNA, Circular; D004279:DNA, Viral; D014568:Urokinase-Type Plasminogen Activator