|Title||Mice expressing minimally humanized CD81 and occludin genes support hepatitis C virus uptake in vivo.|
|Publication Type||Journal Article|
|Year of Publication||2016|
|Authors||Ding, Q, von Schaewen, M, Hrebikova, G, Heller, B, Sandmann, L, Plaas, M, Ploss, A|
|Date Published||2016 12 07|
Hepatitis C virus (HCV) causes chronic infections in at least 150 million individuals world-wide. HCV has a narrow host range and robustly infects only humans and chimpanzees. The underlying mechanisms for this narrow host range are incompletely understood. At the level of entry differences in the amino acid sequences between the human and mouse orthologues of two essential host factors, the tetraspannin CD81 and the tight junction protein occludin (OCLN) explain at least in part HCV's limited ability to enter mouse hepatocytes. We have previously shown that adenoviral or transgenic overexpression of human CD81 and OCLN facilitates HCV uptake into mouse hepatocytes in vitro and in vivo In efforts to refine these models we constructed knock-in mice in which the second extracellular loops of CD81 and OCLN were replaced with the respective human sequences, which contain the determinants that are critical of HCV uptake. We demonstrate that the humanized CD81 and OCLN are expressed at physiologic levels in a tissue-appropriate fashion. Mice bearing the humanized alleles form normal tight junctions and do not exhibit any immunologic abnormalities, indicating that interactions with their physiologic ligands are intact. HCV entry factor knock-in mice enable HCV uptake with similar efficiency as mice expressing HCV entry factors transgenically or adenovirally, demonstrating the utility of this model for studying HCV infection in vivo IMPORTANCE: At least 150 million individuals are chronically infected with hepatitis C virus (HCV). Chronic hepatitis C can result in progressive liver disease and liver cancer. New antiviral treatments can cure HCV in the majority of patients but a vaccine remains elusive. To gain a better understanding of the processes culminating in liver failure and cancer and to prioritize more efficiently vaccine candidates, small animal models are needed. Here, we describe the characterization of a new mouse model in which the parts of two host factors that are essential for HCV uptake, CD81 and occludin (OCLN) which differ between mice and men were humanized. We demonstrate that such minimally humanized mice develop normally, express the modified genes at physiological levels and support HCV uptake. This model is of considerable utility for studying viral entry in the three dimensional context of the liver and to test approaches aimed at preventing HCV entry.
|Alternate Journal||J. Virol.|