Hepatitis C virus infection mediates cholesteryl ester synthesis to facilitate infectious particle production

Abstract

Cholesterol is a critical component of the hepatitis C virus (HCV) life cycle, as demonstrated by its accumulation within infected hepatocytes and lipoviral particles. To cope with excess cholesterol, hepatic enzymes ACAT1 and ACAT2 produce cholesteryl esters (CEs), which are destined for storage in lipid droplets or for secretion as apolipoproteins. Here we demonstrate in vitro that cholesterol accumulation following HCV infection induces upregulation of the ACAT genes and increases CE synthesis. Analysis of human liver biopsy tissue showed increased ACAT2 mRNA expression in liver infected with HCV genotype 3, compared with genotype 1. Inhibiting cholesterol esterification using the potent ACAT inhibitor TMP-153 significantly reduced production of infectious virus, but did not inhibit virus RNA replication. Density gradient analysis showed that TMP-153 treatment caused a significant increase in lipoviral particle density, suggesting reduced lipidation. These data suggest that cholesterol accumulation following HCV infection stimulates the production of CE, a major component of lipoviral particles. Inhibition of CE synthesis reduces HCV particle density and infectivity, suggesting that CEs are required for optimal infection of hepatocytes.

Zinc is a potent and specific inhibitor of IFN-λ3 signalling

“…Approximately 1–2 weeks post electroporation, HCV infectivity was measured by qPCR and immunofluorescence using an anti-NS5A antibody (kindly provided by Prof. Mark Harris, University of Leeds, UK) as in ref. 73 and RNA was extracted.…”

HCV 3a Core Protein Increases Lipid Droplet Cholesteryl Ester Content via a Mechanism Dependent on Sphingolipid Biosynthesis

“…HCV core 3a-expressing cells displayed a 1.8-fold increase of SOAT-2 expression when compared to GFP control cells. Therefore, we treated those cells with TMP-153, a SOAT inhibitor, which has been recently used in the context of HCV infection [28]. SOAT inhibition counteracted the increase of both CE level and LD size, induced by the HCV core 3a ( Fig.…”

Hepatitis C virus p7 mediates membrane-to-membrane adhesion

“…If cholesterol is eliminated by methyl-β-cyclodextrin treatment, core protein is not detected in the detergent-resistant membrane (DRM) fraction [11]. In addition to this result, sphingolipids and cholesterol are increased in the ER of HCV-infected host cells [14,15] and the down-regulation of synthesis of sphingolipids decreases HCV production [12]. Interestingly, HCV production is also decreased if polyunsaturated ER liposome (PERL) is used to reduce cholesterol in the ER membrane, but PERL has no major effect on RNA replication and protein expression [16].…”