Human hepatocyte depletion in the presence of HIV-1 infection in dual reconstituted humanized mice.

Raghubendra Singh Dagur,Edward Makarov,Larisa Y Poluektova,Weimin Wang,Santhi Gorantla,Catherine L Gebhart,Natalia Osna,Hiroshi Suemizu,Murali Ganesan,Yan Cheng

doi:10.1242/bio.029785

Abstract

ABSTRACTHuman immunodeficiency virus type 1 (HIV-1) infection impairs liver function, and liver diseases have become a leading cause of morbidity in infected patients. The immunopathology of liver damage caused by HIV-1 remains unclear. We used chimeric mice dually reconstituted with a human immune system and hepatocytes to address the relevance of the model to pathobiology questions related to human hepatocyte survival in the presence of systemic infection. TK-NOG males were transplanted with mismatched human hematopoietic stem/progenitor cells and hepatocytes, human albumin concentration and the presence of human immune cells in blood were monitored for hepatocytes and immune reconstitution, and mice were infected with HIV-1. HIV-1-infected animals showed a decline in human albumin concentration with a significant reduction in percentage of human hepatocytes compared to uninfected mice. The decrease in human albumin levels correlated with a decline in CD4+ cells in the liver and with an increase in HIV-1 viral load. HIV-1 infection elicited proinflammatory response in the immunological milieu of the liver in HIV-infected mice compared to uninfected animals, as determined by upregulation of IL23, CXCL10 and multiple toll-like receptor expression. The inflammatory reaction associated with HIV-1 infection in vivo could contribute to the depletion and dysfunction of hepatocytes. The dual reconstituted TK-NOG mouse model is a feasible platform to investigate hepatocyte-related HIV-1 immunopathogenesis.This article has an associated First Person interview with the first author of the paper.

Highlights

human immunodeficiency virus (HIV) type 1 (HIV-1) infection reduces human ALB levels and hepatocyte population in dual reconstituted mice To assess the effect of HIV infection on the liver of dual reconstituted mice, we transplanted mice with human Hep from a single donor and human CD34+ hematopoietic stem/progenitor cell (HSPC) from single donors simultaneously to achieve double reconstitution with human liver cells and a hemato-lymphoid system
When humanization of liver and immune system establishment was evident (∼5 months of age), mice were infected with HIV-1ADA 104 tissue culture infectious doses 50 (TCID50) intraperitoneally, and euthanized at 5 weeks post-infection (Hep+CD34+HIV mice)
The staining of liver fixed and paraffin-embedded tissue sections with human-specific antibodies to CXCL10, TLR9 and TLR7 confirmed the presence of these proteins in immune cell infiltrates (Fig. 4B). These findings suggest that exposure of human hepatocytes to HIV-1 in combination with the presence of activated and infected human immune cells play a key role in liver damage

Summary

Introduction

We sought to investigate how a mismatched model and possible alloreactivity would affect outcomes To explore such mismatched experimental conditions, we created dual liver- and immune systemtransplanted humanized mice and addressed the effects of HIV1 on hepatocyte survival and function. In this experimental system, we used Hep derived from a single donor for transplantation into NOD/scid-IL2Rγcnull (NOG) mice expressing the herpes simplex virus type 1 thymidine kinase (TK) transgene within the liver (TK-NOG) (Hasegawa et al, 2011). To explore the processes that could be involved in Hep damage in dual reconstituted humanized mice, we evaluated the presence of infected cells in liver tissue as well as the pathomorphology associated with this observation. The depletion of human hepatocytes and the decline of human ALB levels in vivo could be results of HIV-1 infection of the liverimmune cell milieu and not related to mismatched transplantation of human HSPCs and hepatocytes

Methods

Results

Conclusion