Dataset Information

HCV induces the expression of Rubicon and UVRAG to temporally regulate the maturation of autophagosomes and viral replication.

ABSTRACT: Hepatitis C virus (HCV) induces autophagy to enhance its replication. However, how HCV regulates the autophagic pathway remains largely unclear. In this report, we demonstrated that HCV infection could induce the expression of Rubicon and UVRAG, which inhibited and stimulated the maturation of autophagosomes, respectively. The induction of Rubicon by HCV was prompt whereas the induction of UVRAG was delayed, resulting in the accumulation of autophagosomes in the early time points of viral infection. The role of Rubicon in inhibiting the maturation of autophagosomes in HCV-infected cells was confirmed by siRNA knockdown and the over-expression of Rubicon, which enhanced and suppressed the maturation of autophagosomes, respectively. Rubicon played a positive role in HCV replication, as the suppression of its expression reduced HCV replication and its over-expression enhanced HCV replication. In contrast, the over-expression of UVRAG facilitated the maturation of autophagosomes and suppressed HCV replication. The HCV subgenomic RNA replicon, which expressed only the nonstructural proteins, could also induce the expression of Rubicon and the accumulation of autophagosomes. Further analysis indicated that the HCV NS4B protein was sufficient to induce Rubicon and autophagosomes. Our results thus indicated that HCV, by differentially inducing the expression of Rubicon and UVRAG, temporally regulated the autophagic flux to enhance its replication.

SUBMITTER: Wang L

PROVIDER: S-EPMC4373777 | biostudies-literature | 2015 Mar

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

HCV induces the expression of Rubicon and UVRAG to temporally regulate the maturation of autophagosomes and viral replication.

Wang Linya L Tian Yongjun Y Ou Jing-hsiung James JH

PLoS pathogens 20150325 3

Hepatitis C virus (HCV) induces autophagy to enhance its replication. However, how HCV regulates the autophagic pathway remains largely unclear. In this report, we demonstrated that HCV infection could induce the expression of Rubicon and UVRAG, which inhibited and stimulated the maturation of autophagosomes, respectively. The induction of Rubicon by HCV was prompt whereas the induction of UVRAG was delayed, resulting in the accumulation of autophagosomes in the early time points of viral infect ...[more]

PMID: 25807108

Similar Datasets

Project description:Autophagy plays important roles in maintaining cellular homeostasis. It uses double- or multiple-membrane vesicles termed autophagosomes to remove protein aggregates and damaged organelles from the cytoplasm for recycling. Hepatitis C virus (HCV) has been shown to induce autophagy to enhance its own replication. Here we describe a procedure that combines membrane flotation and affinity chromatography for the purification of autophagosomes from cells that harbor an HCV subgenomic RNA replicon. The purified autophagosomes had double- or multiple-membrane structures with a diameter ranging from 200 nm to 600 nm. The analysis of proteins associated with HCV-induced autophagosomes by proteomics led to the identification of HCV nonstructural proteins as well as proteins involved in membrane trafficking. Notably, caveolin-1, caveolin-2, and annexin A2, which are proteins associated with lipid rafts, were also identified. The association of lipid rafts with HCV-induced autophagosomes was confirmed by Western blotting, immunofluorescence microscopy, and immunoelectron microscopy. Their association with autophagosomes was also confirmed in HCV-infected cells. The association of lipid rafts with autophagosomes was specific to HCV, as it was not detected in autophagosomes induced by nutrient starvation. Further analysis indicated that the autophagosomes purified from HCV replicon cells could mediate HCV RNA replication in a lipid raft-dependent manner, as the depletion of cholesterol, a major component of lipid rafts, from autophagosomes abolished HCV RNA replication. Our studies thus demonstrated that HCV could specifically induce the association of lipid rafts with autophagosomes for its RNA replication.IMPORTANCE HCV can cause severe liver diseases, including cirrhosis and hepatocellular carcinoma, and is one of the most important human pathogens. Infection with HCV can lead to the reorganization of membrane structures in its host cells, including the induction of autophagosomes. In this study, we developed a procedure to purify HCV-induced autophagosomes and demonstrated that HCV could induce the localization of lipid rafts to autophagosomes to mediate its RNA replication. This finding provided important information for further understanding the life cycle of HCV and its interaction with the host cells.

Project description:Transcriptional profiling provides global snapshots of virus-mediated cellular reprogramming, which can simultaneously encompass pro- and antiviral components. To determine early transcriptional signatures associated with HCV infection of authentic target cells, we performed ex vivo infections of adult primary human hepatocytes (PHHs) from seven donors. Longitudinal sampling identified minimal gene dysregulation at six hours post infection (hpi). In contrast, at 72 hpi, massive increases in the breadth and magnitude of HCV-induced gene dysregulation were apparent, affecting gene classes associated with diverse biological processes. Comparison with HCV-induced transcriptional dysregulation in Huh-7.5 cells identified limited overlap between the two systems. Of note, in PHHs, HCV infection initiated broad upregulation of canonical interferon (IFN)-mediated defense programs, limiting viral RNA replication and abrogating virion release. We further find that constitutive expression of IRF1 in PHHs maintains a steady-state antiviral program in the absence of infection, which can additionally reduce HCV RNA translation and replication. We also detected infection-induced downregulation of ∼90 genes encoding components of the EIF2 translation initiation complex and ribosomal subunits in PHHs, consistent with a signature of translational shutoff. As HCV polyprotein translation occurs independently of the EIF2 complex, this process is likely pro-viral: only translation initiation of host transcripts is arrested. The combination of antiviral intrinsic and inducible immunity, balanced against pro-viral programs, including translational arrest, maintains HCV replication at a low-level in PHHs. This may ultimately keep HCV under the radar of extra-hepatocyte immune surveillance while initial infection is established, promoting tolerance, preventing clearance and facilitating progression to chronicity.IMPORTANCEAcute HCV infections are often asymptomatic and therefore frequently undiagnosed. We endeavored to recreate this understudied phase of HCV infection using explanted PHHs and monitored host responses to initial infection. We detected temporally distinct virus-induced perturbations in the transcriptional landscape, which were initially narrow but massively amplified in breadth and magnitude over time. At 72 hpi, we detected dysregulation of diverse gene programs, concurrently promoting both virus clearance and virus persistence. On the one hand, baseline expression of IRF1 combined with infection-induced upregulation of IFN-mediated effector genes suppresses virus propagation. On the other, we detect transcriptional signatures of host translational inhibition, which likely reduces processing of IFN-regulated gene transcripts and facilitates virus survival. Together, our data provide important insights into constitutive and virus-induced transcriptional programs in PHHs, and identifies simultaneous antagonistic dysregulation of pro-and anti-viral programs which may facilitate host tolerance and promote viral persistence.

Dataset Information

HCV induces the expression of Rubicon and UVRAG to temporally regulate the maturation of autophagosomes and viral replication.

Publications

HCV induces the expression of Rubicon and UVRAG to temporally regulate the maturation of autophagosomes and viral replication.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets