Humanized chimeric uPA mouse model for the study of hepatitis B and D virus interactions and preclinical drug evaluation

Abstract

No specific drugs are currently available against hepatitis delta virus (HDV), a defective virus leading to the most severe form of chronic viral hepatitis in man. The lack of convenient HDV infection models has hampered the development of effective therapeutics. In this study, naïve and hepatitis B virus (HBV) chronically infected humanized uPA/SCID mice were employed to establish a small animal model of HBV/HDV coinfection and superinfection. For preclinical antiviral drug evaluation, the GMP version of the myristoylated preS-peptide (Myrcludex-B), a lipopeptide derived from the pre-S1 domain of the HBV envelope, was applied to prevent de novo HBV/HDV coinfection in vivo. Virological parameters were determined at serological and intrahepatic level both by real-time polymerase chain reaction (PCR) and by immunohistochemistry. Establishment of HDV infection was highly efficient in both HBV-infected and naïve chimeric mice with HDV titers rising up to 1 3 10E9 copies/mL. Notably, HDV superinfection led to a median 0.6log reduction of HBV viremia, which although not statistically significant suggests that HDV may hinder HBV replication. In the setting of HBV/HDV simultaneous infection, a majority of human hepatocytes stained HDAg-positive long before HBV spreading was completed, confirming that HDV can replicate intrahepatically also in the absence of HBV infection. Furthermore, the increase of HBV viremia and intrahepatic cccDNA loads was significantly slower than in HBV mono-infected mice. Treatment with the HBV entry inhibitor Myrcludex-B, efficiently hindered the establishment of HDV infection in vivo. Conclusion: We established an efficient model of HBV/HDV infection to exploit mechanisms of viral interference in human hepatocytes and to test the efficacy of an HDV-entry inhibitor in vivo. (HEPATOLOGY 2012;55:685-694) A pproximately 20 million individuals are chronically infected with hepatitis delta virus (HDV) worldwide. Chronic HDV infection is considered the most severe form of viral hepatitis, because it is associated with an accelerated course of fibrosis progression and liver cirrhosis in up to 70% of patients, and the highest risk for liver decompensation and development of hepatocellular carcinoma.

Effect of interferon‐alpha therapy on hepatitis D virus

“…It is difficult to be sure which virus life cycle is reflected by this delay because HDV can infect cells that are not already infected with HBV, but requires HBV infection to be able to produce new virus. 4 This 8.5-day duration is consistent with a 7.9-day half-life estimate of HBV-infected cells. 5 The very long 2.9-day half-life estimate for HDV virions is also unlikely to be correct.…”

“…4 Accordingly, they suggest that the long delay observed here (median t 0 5 8.5 days) indicates that IFN acts mainly on blocking new infection, rather than blocking viral production, and that the intracellular infection life cycle (termed here eclipse phase) of HDV or of hepatitis B virus (HBV) should be close to 8.5 days. However, a study of severe combined immunodeficiency mice with humanized liver indicates that the HDV and HBV eclipse phases are shorter than 8.5 days.…”

Modification of Three Amino Acids in Sodium Taurocholate Cotransporting Polypeptide Renders Mice Susceptible to Infection with Hepatitis D Virus In Vivo

“…In contrast to immunodeficient uPA/SCID mice (31,32) or Fah Ϫ/Ϫ Rag2 Ϫ/Ϫ Il2rg Ϫ/Ϫ mice (33, 34) with humanized liver for HDV and HBV infection, the susceptibility to HDV infection in our mouse with NTCP modification is inheritable and of more convenience for use. No transplantation process is needed for the new model; thus much less time and lower costs are required for the experiment.…”

An Ex Vivo Perfusion System Emulating In Vivo Conditions in Noncirrhotic and Cirrhotic Human Liver

“…Specifically, cell lines sometimes critically differ from their healthy counterparts and, on the opposite side of the spectrum, even humanized (chimeric) animal models do not entirely reflect the actual situation in patients. They may differ in their (patho)physiologies, modes of infection, pharmacological metabolization, and toxicity characteristics and are, moreover, especially fragile (Tateno et al, 2004;Dandri et al, 2005;Vanwolleghem et al, 2010;Lü tgehetmann et al, 2012). Such limitations may be remedied with a suitable human-based perfusion system, even more so if such a system can maintain certain pathological conditions.…”