Metabolism of phosphatidylinositol 4-kinase IIIα-dependent PI4P Is subverted by HCV and is targeted by a 4-anilino quinazoline with antiviral activity.

Department of Genomics and Molecular Biology, Virology Program, Istituto Nazionale Genetica Molecolare (INGM), Milano, Italy.
PLoS Pathogens (Impact Factor: 8.06). 03/2012; 8(3):e1002576. DOI: 10.1371/journal.ppat.1002576
Source: PubMed

ABSTRACT 4-anilino quinazolines have been identified as inhibitors of HCV replication. The target of this class of compounds was proposed to be the viral protein NS5A, although unequivocal proof has never been presented. A 4-anilino quinazoline moiety is often found in kinase inhibitors, leading us to formulate the hypothesis that the anti-HCV activity displayed by these compounds might be due to inhibition of a cellular kinase. Type III phosphatidylinositol 4-kinase α (PI4KIIIα) has recently been identified as a host factor for HCV replication. We therefore evaluated AL-9, a compound prototypical of the 4-anilino quinazoline class, on selected phosphatidylinositol kinases. AL-9 inhibited purified PI4KIIIα and, to a lesser extent, PI4KIIIβ. In Huh7.5 cells, PI4KIIIα is responsible for the phosphatidylinositol-4 phosphate (PI4P) pool present in the plasma membrane. Accordingly, we observed a gradual decrease of PI4P in the plasma membrane upon incubation with AL-9, indicating that this agent inhibits PI4KIIIα also in living cells. Conversely, AL-9 did not affect the level of PI4P in the Golgi membrane, suggesting that the PI4KIIIβ isoform was not significantly inhibited under our experimental conditions. Incubation of cells expressing HCV proteins with AL-9 induced abnormally large clusters of NS5A, a phenomenon previously observed upon silencing PI4KIIIα by RNA interference. In light of our findings, we propose that the antiviral effect of 4-anilino quinazoline compounds is mediated by the inhibition of PI4KIIIα and the consequent depletion of PI4P required for the HCV membranous web. In addition, we noted that HCV has a profound effect on cellular PI4P distribution, causing significant enrichment of PI4P in the HCV-membranous web and a concomitant depletion of PI4P in the plasma membrane. This observation implies that HCV--by recruiting PI4KIIIα in the RNA replication complex--hijacks PI4P metabolism, ultimately resulting in a markedly altered subcellular distribution of the PI4KIIIα product.

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Hepatitis C Virus (HCV) infects over 150 million people worldwide. In most cases HCV infection becomes chronic, causing liver disease ranging from fibrosis to cirrhosis and hepatocellular carcinoma. HCV affects the cholesterol homeostasis and at the molecular level, every step of the virus life cycle is intimately connected to lipid metabolism. In this review, we present an update on the lipids and apolipoproteins that are involved in the HCV infectious cycle steps: entry, replication and assembly. Moreover, the result of the assembly process is a lipoviroparticle, which represents a peculiarity of hepatitis C virion. This review illustrates an example of an intricate virus-host interaction governed by lipid metabolism.
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Similar to other positive-strand RNA viruses, rhinovirus, the causative agent of the common cold, replicates on a web of cytoplasmic membranes, orchestrated by host proteins and lipids. The host pathways that facilitate the formation and function of the replication membranes and complexes are poorly understood. We show that rhinovirus replication depends on host factors driving phosphatidylinositol 4-phosphate (PI4P)-cholesterol counter-currents at viral replication membranes. Depending on the virus type, replication required phosphatidylinositol 4-kinase class 3beta (PI4K3b), cholesteryl-esterase hormone-sensitive lipase (HSL) or oxysterol-binding protein (OSBP)-like 1, 2, 5, 9, or 11 associated with lipid droplets, endosomes, or Golgi. Replication invariably required OSBP1, which shuttles cholesterol and PI4P between ER and Golgi at membrane contact sites. Infection also required ER-associated PI4P phosphatase Sac1 and phosphatidylinositol (PI) transfer protein beta (PITPb) shunting PI between ER-Golgi. These data support a PI4P-cholesterol counter-flux model for rhinovirus replication. Copyright © 2014 Elsevier Inc. All rights reserved.
    Cell Host & Microbe 11/2014; 16(5):677-690. DOI:10.1016/j.chom.2014.10.003 · 12.19 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Hepatitis C virus (HCV) is a major global health burden accounting for around 170 million chronic infections worldwide. Although highly potent direct-acting antiviral drugs to treat chronic hepatitis C have been approved recently, owing to their high costs and limited availability and a large number of undiagnosed infections, the burden of disease is expected to rise in the next few years. In addition, HCV is an excellent paradigm for understanding the tight link between a pathogen and host cell pathways, most notably lipid metabolism. HCV extensively remodels intracellular membranes to establish its cytoplasmic replication factory and also usurps components of the intercellular lipid transport system for production of infectious virus particles. Here, we review the molecular mechanisms of viral replicase function, cellular pathways employed during HCV replication factory biogenesis, and viral, as well as cellular, determinants of progeny virus production.
    Cell Host & Microbe 11/2014; 16(5):569-579. DOI:10.1016/j.chom.2014.10.008 · 12.19 Impact Factor

Full-text (3 Sources)

Available from
May 27, 2014