Use of the upa chimeric mouse model for the study of hepadnaviral repliction and stability of cccDNA molecules
Final Report Abstract
Chronic infection with HBV appears to be due to both a weak immune response raised against the virus and to maintenance of the covalently closed circular DNA (cccDNA), the template of viral transcription in infected hepatocytes. Our hypothesis is that destabilization of the cccDNA and enhancement of host immune responses may permit clearance of HBV chronic infection. Thus, the major focus of the proposal was to improve and use a unique mouse model, which permits stable repopulation of the mouse livers with primary human hepatocytes and hence it enables establishment of infection with human hepatotropic viruses, like HBV, to investigate mechanisms of cccDNA stability and activity in the context of viral infection. In particular, our purpose was to investigate factors which may affect the stability of the cccDNA in vivo. Our studies provided direct evidence that cell division in the setting of liver regeneration and without administration of antiviral drugs induced strong destabilization of the cccDNA reservoir, as well as rapid reduction of viral productivity in infected cells repopulating the livers of the uPA mice. Mathematic modelling and experiments performed in uPA mice indicated that the half-life of circulating HBV particles is short (only hours) and comparable to the HBV half-life determined in high viremic chronic carriers, though it appeared to be less affected by viremia levels, suggesting that additional factors, probably host defence mechanisms, may accelerate clearance kinetics in serum of HBV-chronic carriers. Our recent studies on dynamics of HBV infection and de novo cccDNA accumulation indicated that HBV infection in vivo and conversion of input rcDNA to cccDNA is a relatively slow process in human hepatocytes. Interestingly, intracellular cccDNA amplification appeared to be not required for high virion productivity in our human-chimeric mouse system. We recently used the mouse system to explore the potential of novel antiviral substances with the aim of exploring possible consequences on cccDNA accumulation and stability. Within the funding period, both the in vivo antiviral efficacy of interferon, of new polymerase inhibitors, as well as the potential of HBV entry inhibitors to block the establishment of HBV infection were tested in vivo. Most of the experiments planed within the research project funded by the DFG have been carried out and have received international recognition through congress presentations and publications in high ranking peer-reviewed journals, like Nature, Gastroenterology and Hepatology.
Publications
- Peginterferon alpha-2b plus adefovir induce strong cccDNA decline and HBsAg reduction in patients with chronic hepatitis B. Hepatology 2006;44:675-84
Wursthorn K, Lutgehetmann M, Dandri M, Volz T, Buggisch P, Zollner B, Longerich T, Schirmacher P, Metzler F, Zankel M, Fischer C, Currie G, Brosgart C, Petersen J
- Small animal model systems for studying hepatitis B virus replication and pathogenesis. Semin Liver Dis 2006;26:181-91
Dandri M, Lutgehetmann M, Volz T, Petersen J
- Impaired intrahepatic hepatitis B virus productivity contributes to low viremia in most HBeAg-negative patients. Gastroenterology. 2007 Sep;133(3):843-52. Epub 2007 Jul 3
Volz T, Lutgehetmann M, Wachtler P, Jacob A, Quaas A, Murray JM, Dandri M, Petersen J
- Prevention of hepatitis B virus infection in vivo by entry inhibitors derived from the large envelope protein. Nature Biotechnol. 2008 Mar;26(3):335-41. Epub 2008 Feb 24
Petersen J, Dandri M, Mier W, Lutgehetmann M, Volz T, von Weizsäcker F, Haberkorn U, Fischer L, Pollok JM, Erbes B, Seitz S, Urban S
- Sequential combination therapy leads to biochemical and histological improvement despite low ongoing intrahepatic hepatitis B virus replication. Antivir Ther. 2008;13(1):57-66
Lutgehetmann M, Volz T, Quaas A, Zankel M, Fischer C, Dandri M, Petersen J
- Virion half-life in chronic hepatitis B infection is strongly correlated with levels of viremia. Hepatology. 2008 Oct;48(4):1079-86
Dandri M, Murray JM, Lutgehetmann M, Volz T, Lohse AW, Petersen J
- Control of cccDNA function in hepatitis B virus infection. J Hepatol. 2009 Sep;51(3):581-92. Epub 2009 Jun 10
Levrero M, Pollicino T, Petersen J, Belloni L, Raimondo G, Dandri M
- In vivo proliferation of hepadnavirus-infected hepatocytes induces loss of covalently closed circular DNA in mice. Hepatology. 2010 Jul; 52(1):16-24
Lutgehetmann M, Volz T, Köpke A, Broja T, Tigges E, Lohse AW, Fuchs E, Murray JM, Petersen J, Dandri M
- The replication cycle of hepatitis B virus. J Hepatol. 2010 Feb;52(2):282-4. Epub 2009 Nov 24
Urban S, Schulze A, Dandri M, Petersen J
