Fibrogenic Gene Expression in Hepatic Stellate Cells Induced by HCV and HIV Replication in a Three Cell Co-Culture Model System

Abdellah Akil,Mark Endsley,Minkyung Yi,Omar Saldarriaga,Saravanabalaji Shanmugam,Heidi Spratt,Netanya S Utay,Anoma Somasunderam,Monique Ferguson,Heather L Stevenson

doi:10.1038/s41598-018-37071-y

Abstract

Retrospective studies indicate that co-infection of hepatitis C virus (HCV) and human immunodeficiency virus (HIV) accelerates hepatic fibrosis progression. We have developed a co-culture system (MLH) comprising primary macrophages, hepatic stellate cells (HSC, LX-2), and hepatocytes (Huh-7), permissive for active replication of HCV and HIV, and assessed the effect of these viral infections on the phenotypic changes and fibrogenic gene expression in LX-2 cells. We detected distinct morphological changes in LX-2 cells within 24 hr post-infection with HCV, HIV or HCV/HIV in MLH co-cultures, with migration enhancement phenotypes. Human fibrosis microarrays conducted using LX-2 cell RNA derived from MLH co-culture conditions, with or without HCV and HIV infection, revealed novel insights regarding the roles of these viral infections on fibrogenic gene expression in LX-2 cells. We found that HIV mono-infection in MLH co-culture had no impact on fibrogenic gene expression in LX-2 cells. HCV infection of MLH co-culture resulted in upregulation (>1.9x) of five fibrogenic genes including CCL2, IL1A, IL1B, IL13RA2 and MMP1. These genes were upregulated by HCV/HIV co-infection but in a greater magnitude. Conclusion: Our results indicate that HIV-infected macrophages accelerate hepatic fibrosis during HCV/HIV co-infection by amplifying the expression of HCV-dependent fibrogenic genes in HSC.

Highlights

Due to a shared route of transmission via infected human blood, hepatitis C virus (HCV) and human immunodeficiency virus (HIV) co-infections are relatively common with estimated 2.3 million people living with HCV/HIV co-infection globally[15]
Primary human monocyte-derived Mφ were infected with HIV24 and co-culture was established by addition of Huh-7 cells, with or without HCV infection, as well as LX-2 cells
We have developed an in vitro co-culture system (MLH) consisting of three major cell types in the liver involved in hepatic fibrosis development, including primary Mφ, HSC (LX-1) and hepatocytes (Huh-7), permissive for active replication of HCV and HIV

Summary

Introduction

Due to a shared route of transmission via infected human blood, HCV and human immunodeficiency virus (HIV) co-infections are relatively common with estimated 2.3 million people living with HCV/HIV co-infection globally[15]. Different in vitro approaches have been developed to mimic hepatic microenvironment to better understand the pathogenesis of HCV infection or HCV/HIV co-infection-mediated hepatic fibrosis. One such system was HSC monoculture incubated with heat inactivated HCV, HIV or conditioned medium from these virus infected cells[12,20]. Other studies employed a HSC/hepatocyte bi-culture system to study the mechanism of hepatic fibrosis caused by HCV21 or HIV/HCV co-infection[18], respectively These bi-culture model systems support HCV infection due to inclusion of hepatocytes, they lack macrophages (Mφ), the primary cell type supporting HIV replication. Our study revealed that active replication of HIV in Mφ amplified the selective fibrogenic signals in HSC induced by HCV replication in hepatocytes under three cell co-culture condition in a Mφ-dependent manner

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