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Smirnov A, Magri A, Lotz R, Han X, Yin C, Harris M, Osterburg C, Dötsch V, McKeating JA, Lu X. ASPP2 binds to hepatitis C virus NS5A protein via an SH3 domain/PxxP motif-mediated interaction and potentiates infection. J Gen Virol 2023; 104:10.1099/jgv.0.001895. [PMID: 37750869 PMCID: PMC7615710 DOI: 10.1099/jgv.0.001895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/27/2023] Open
Abstract
Hepatitis C virus (HCV) infects millions of people worldwide and is a leading cause of liver disease. Despite recent advances in antiviral therapies, viral resistance can limit drug efficacy and understanding the mechanisms that confer viral escape is important. We employ an unbiased interactome analysis to discover host binding partners of the HCV non-structural protein 5A (NS5A), a key player in viral replication and assembly. We identify ASPP2, apoptosis-stimulating protein of p53, as a new host co-factor that binds NS5A via its SH3 domain. Importantly, silencing ASPP2 reduces viral replication and spread. Our study uncovers a previously unknown role for ASPP2 to potentiate HCV RNA replication.
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Affiliation(s)
- Artem Smirnov
- Ludwig Institute for Cancer Research, Nuffield Department of Clinical Medicine, University of Oxford, Oxford OX3 7DQ, UK
- Department of Experimental Medicine, TOR, University of Rome “Tor Vergata”, Rome 00133, Italy
| | - Andrea Magri
- Nuffield Department of Clinical Medicine, University of Oxford, Oxford OX3 7FZ, UK
| | - Rebecca Lotz
- Institute of Biophysical Chemistry and Center for Biomolecular Magnetic Resonance, Goethe University, Frankfurt, Germany
| | - Xiaoyue Han
- Ludwig Institute for Cancer Research, Nuffield Department of Clinical Medicine, University of Oxford, Oxford OX3 7DQ, UK
| | - Chunhong Yin
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, UK
| | - Mark Harris
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, UK
| | - Christian Osterburg
- Institute of Biophysical Chemistry and Center for Biomolecular Magnetic Resonance, Goethe University, Frankfurt, Germany
| | - Volker Dötsch
- Institute of Biophysical Chemistry and Center for Biomolecular Magnetic Resonance, Goethe University, Frankfurt, Germany
| | - Jane A. McKeating
- Nuffield Department of Clinical Medicine, University of Oxford, Oxford OX3 7FZ, UK
- Chinese Academy of Medical Sciences Oxford Institute, University of Oxford, Oxford, UK
| | - Xin Lu
- Ludwig Institute for Cancer Research, Nuffield Department of Clinical Medicine, University of Oxford, Oxford OX3 7DQ, UK
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Avula K, Singh B, Samantaray S, Syed GH. The Early Secretory Pathway Is Crucial for Multiple Aspects of the Hepatitis C Virus Life Cycle. J Virol 2023:e0018023. [PMID: 37338368 PMCID: PMC10373535 DOI: 10.1128/jvi.00180-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Accepted: 06/02/2023] [Indexed: 06/21/2023] Open
Abstract
Although most of the early events of the hepatitis C virus (HCV) life cycle are well characterized, our understanding of HCV egress is still unclear. Some reports implicate the conventional endoplasmic reticulum (ER)-Golgi route, while some propose noncanonical secretory routes. Initially, the envelopment of HCV nucleocapsid occurs by budding into the ER lumen. Subsequently, the HCV particle exit from the ER is assumed to be mediated by coat protein complex II (COPII) vesicles. COPII vesicle biogenesis also involves the recruitment of cargo to the site of vesicle biogenesis via interaction with COPII inner coat proteins. We investigated the modulation and the specific role of the individual components of the early secretory pathway in HCV egress. We observed that HCV inhibits cellular protein secretion and triggers the reorganization of the ER exit sites and ER-Golgi intermediate compartments (ERGIC). Gene-specific knockdown of the components of this pathway such as SEC16A, TFG, ERGIC-53, and COPII coat proteins demonstrated the functional significance of these components and the distinct role played by these proteins in various aspects of the HCV life cycle. SEC16A is essential for multiple steps in the HCV life cycle, whereas TFG is specifically involved in HCV egress and ERGIC-53 is crucial for HCV entry. Overall, our study establishes that the components of the early secretory pathway are essential for HCV propagation and emphasize the importance of the ER-Golgi secretory route in this process. Surprisingly, these components are also required for the early stages of the HCV life cycle due to their role in overall intracellular trafficking and homeostasis of the cellular endomembrane system. IMPORTANCE The virus life cycle involves entry into the host, replication of the genome, assembly of infectious progeny, and their subsequent release. Different aspects of the HCV life cycle, including entry, genome replication, and assembly, are well characterized; however, our understanding of the HCV release is still not clear and subject to debate due to varied findings. Here, we attempted to address this controversy and enhance our understanding of HCV egress by evaluating the role of the different components of the early secretory pathway in the HCV life cycle. To our surprise, we found that the components of the early secretory pathway are not only essential for HCV release but also contribute to many other earlier events of the HCV life cycle. This study emphasizes the importance of the early secretory pathway for the establishment of productive HCV infection in hepatocytes.
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Affiliation(s)
- Kiran Avula
- Institute of Life Sciences, Bhubaneswar, Odisha, India
- Regional Centre for Biotechnology, Faridabad, Delhi, India
| | - Bharati Singh
- Institute of Life Sciences, Bhubaneswar, Odisha, India
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Vormittag S, Ende RJ, Derré I, Hilbi H. Pathogen vacuole membrane contact sites - close encounters of the fifth kind. MICROLIFE 2023; 4:uqad018. [PMID: 37223745 PMCID: PMC10117887 DOI: 10.1093/femsml/uqad018] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 03/30/2023] [Accepted: 04/06/2023] [Indexed: 05/25/2023]
Abstract
Vesicular trafficking and membrane fusion are well-characterized, versatile, and sophisticated means of 'long range' intracellular protein and lipid delivery. Membrane contact sites (MCS) have been studied in far less detail, but are crucial for 'short range' (10-30 nm) communication between organelles, as well as between pathogen vacuoles and organelles. MCS are specialized in the non-vesicular trafficking of small molecules such as calcium and lipids. Pivotal MCS components important for lipid transfer are the VAP receptor/tether protein, oxysterol binding proteins (OSBPs), the ceramide transport protein CERT, the phosphoinositide phosphatase Sac1, and the lipid phosphatidylinositol 4-phosphate (PtdIns(4)P). In this review, we discuss how these MCS components are subverted by bacterial pathogens and their secreted effector proteins to promote intracellular survival and replication.
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Affiliation(s)
| | | | - Isabelle Derré
- Corresponding author. Department of Microbiology, Immunology and Cancer Biology, University of Virginia, 1340 Jefferson Park Ave, Charlottesville, VA 22908, United States. Tel: +1-434-924-2330; E-mail:
| | - Hubert Hilbi
- Corresponding author. Institute of Medical Microbiology, University of Zürich, Gloriastrasse 30, 8006 Zürich, Switzerland. Tel: +41-44-634-2650; E-mail:
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McPhail JA, Burke JE. Molecular mechanisms of PI4K regulation and their involvement in viral replication. Traffic 2023; 24:131-145. [PMID: 35579216 DOI: 10.1111/tra.12841] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Revised: 03/07/2022] [Accepted: 03/30/2022] [Indexed: 11/28/2022]
Abstract
Lipid phosphoinositides are master signaling molecules in eukaryotic cells and key markers of organelle identity. Because of these important roles, the kinases and phosphatases that generate phosphoinositides must be tightly regulated. Viruses can manipulate this regulation, with the Type III phosphatidylinositol 4-kinases (PI4KA and PI4KB) being hijacked by many RNA viruses to mediate their intracellular replication through the formation of phosphatidylinositol 4-phosphate (PI4P)-enriched replication organelles (ROs). Different viruses have evolved unique approaches toward activating PI4K enzymes to form ROs, through both direct binding of PI4Ks and modulation of PI4K accessory proteins. This review will focus on PI4KA and PI4KB and discuss their roles in signaling, functions in membrane trafficking and manipulation by viruses. Our focus will be the molecular basis for how PI4KA and PI4KB are activated by both protein-binding partners and post-translational modifications, with an emphasis on understanding the different molecular mechanisms viruses have evolved to usurp PI4Ks. We will also discuss the chemical tools available to study the role of PI4Ks in viral infection.
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Affiliation(s)
- Jacob A McPhail
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia, Canada
| | - John E Burke
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia, Canada.,Department of Biochemistry and Molecular Biology, The University of British Columbia, Vancouver, British Columbia, Canada
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Chen S, Harris M. NS5A domain I antagonises PKR to facilitate the assembly of infectious hepatitis C virus particles. PLoS Pathog 2023; 19:e1010812. [PMID: 36795772 PMCID: PMC9977016 DOI: 10.1371/journal.ppat.1010812] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Revised: 03/01/2023] [Accepted: 02/02/2023] [Indexed: 02/17/2023] Open
Abstract
Hepatitis C virus NS5A is a multifunctional phosphoprotein comprised of three domains (DI, DII and DIII). DI and DII have been shown to function in genome replication, whereas DIII has a role in virus assembly. We previously demonstrated that DI in genotype 2a (JFH1) also plays a role in virus assembly, exemplified by the P145A mutant which blocked infectious virus production. Here we extend this analysis to identify two other conserved and surface exposed residues proximal to P145 (C142 and E191) that exhibited no defect in genome replication but impaired virus production. Further analysis revealed changes in the abundance of dsRNA, the size and distribution of lipid droplets (LD) and the co-localisation between NS5A and LDs in cells infected with these mutants, compared to wildtype. In parallel, to investigate the mechanism(s) underpinning this role of DI, we assessed the involvement of the interferon-induced double-stranded RNA-dependent protein kinase (PKR). In PKR-silenced cells, C142A and E191A exhibited levels of infectious virus production, LD size and co-localisation between NS5A and LD that were indistinguishable from wildtype. Co-immunoprecipitation and in vitro pulldown experiments confirmed that wildtype NS5A domain I (but not C142A or E191A) interacted with PKR. We further showed that the assembly phenotype of C142A and E191A was restored by ablation of interferon regulatory factor-1 (IRF1), a downstream effector of PKR. These data suggest a novel interaction between NS5A DI and PKR that functions to evade an antiviral pathway that blocks virus assembly through IRF1.
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Affiliation(s)
- Shucheng Chen
- School of Molecular and Cellular Biology, Faculty of Biological Sciences and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, United Kingdom
| | - Mark Harris
- School of Molecular and Cellular Biology, Faculty of Biological Sciences and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, United Kingdom
- * E-mail:
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Lu Y, He P, Zhang Y, Ren Y, Zhang L. The emerging roles of retromer and sorting nexins in the life cycle of viruses. Virol Sin 2022; 37:321-330. [PMID: 35513271 PMCID: PMC9057928 DOI: 10.1016/j.virs.2022.04.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Accepted: 04/12/2022] [Indexed: 02/06/2023] Open
Abstract
Retromer and sorting nexins (SNXs) transport cargoes from endosomes to the trans-Golgi network or plasma membrane. Recent studies have unveiled the emerging roles for retromer and SNXs in the life cycle of viruses, including members of Coronaviridae, Flaviviridae and Retroviridae. Key components of retromer/SNXs, such as Vps35, Vps26, SNX5 and SNX27, can affect multiple steps of the viral life cycle, including facilitating the entry of viruses into cells, participating in viral replication, and promoting the assembly of virions. Here we present a comprehensive updated review on the interplay between retromer/SNXs and virus, which will shed mechanistic insights into controlling virus infection. Retromer/SNXs could regulate viral infection directly or indirectly. Retromer/SNXs plays an important role for SARS-CoV-2 infection. HPV entry is mediated by retromer/SNXs. Retromer is required for HCV replication. Retromer affects the late step of HIV replication.
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Arora A, Taskinen JH, Olkkonen VM. Coordination of inter-organelle communication and lipid fluxes by OSBP-related proteins. Prog Lipid Res 2022; 86:101146. [PMID: 34999137 DOI: 10.1016/j.plipres.2022.101146] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 12/10/2021] [Accepted: 01/03/2022] [Indexed: 12/31/2022]
Abstract
Oxysterol-binding protein (OSBP) and OSBP-related proteins (ORPs) constitute one of the largest families of lipid-binding/transfer proteins (LTPs) in eukaryotes. The current view is that many of them mediate inter-organelle lipid transfer over membrane contact sites (MCS). The transfer occurs in several cases in a 'counter-current' fashion: A lipid such as cholesterol or phosphatidylserine (PS) is transferred against its concentration gradient driven by transport of a phosphoinositide in the opposite direction. In this way ORPs are envisioned to maintain the distinct organelle lipid compositions, with impacts on multiple organelle functions. However, the functions of ORPs extend beyond lipid homeostasis to regulation of processes such as cell survival, proliferation and migration. Important expanding areas of mammalian ORP research include their roles in viral and bacterial infections, cancers, and neuronal function. The yeast OSBP homologue (Osh) proteins execute multifaceted functions in sterol and glycerophospholipid homeostasis, post-Golgi vesicle transport, phosphatidylinositol-4-phosphate, sphingolipid and target of rapamycin (TOR) signalling, and cell cycle control. These observations identify ORPs as lipid transporters and coordinators of signals with an unforeseen variety of cellular processes. Understanding their activities not only enlightens the biology of the living cell but also allows their employment as targets of new therapeutic approaches for disease.
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Affiliation(s)
- Amita Arora
- Minerva Foundation Institute for Medical Research, and Department of Anatomy, Faculty of Medicine, University of Helsinki, Finland
| | - Juuso H Taskinen
- Minerva Foundation Institute for Medical Research, and Department of Anatomy, Faculty of Medicine, University of Helsinki, Finland
| | - Vesa M Olkkonen
- Minerva Foundation Institute for Medical Research, and Department of Anatomy, Faculty of Medicine, University of Helsinki, Finland.
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ORP4L is a prerequisite for the induction of T-cell leukemogenesis associated with human T-cell leukemia virus 1. Blood 2021; 139:1052-1065. [PMID: 34797912 PMCID: PMC8854678 DOI: 10.1182/blood.2021013579] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2021] [Accepted: 11/09/2021] [Indexed: 11/20/2022] Open
Abstract
ORP4L deletion blocks Tax-induced T-cell leukemia, whereas engineering ORP4L expression in T cells results in T-cell leukemia in mice. Loss of miR-31 induced by Tax releases ORP4L expression, which initiates T-cell deterioration, but ORP4L inhibition eliminates ATL in PDX mice.
Human T-cell leukemia virus 1 (HTLV-1) causes adult T-cell leukemia (ATL), but the mechanism underlying its initiation remains elusive. In this study, ORP4L was expressed in ATL cells but not in normal T-cells. ORP4L ablation completely blocked T-cell leukemogenesis induced by the HTLV-1 oncoprotein Tax in mice, whereas engineering ORP4L expression in T-cells resulted in T-cell leukemia in mice, suggesting the oncogenic properties and prerequisite of ORP4L promote the initiation of T-cell leukemogenesis. For molecular insight, we found that loss of miR-31 caused by HTLV-1 induced ORP4L expression in T-cells. ORP4L interacts with PI3Kδ to promote PI(3,4,5)P3 generation, contributing to AKT hyperactivation; NF-κB–dependent, p53 inactivation-induced pro-oncogene expression; and T-cell leukemogenesis. Consistently, ORP4L ablation eliminates human ATL cells in patient-derived xenograft ATL models. These results reveal a plausible mechanism of T-cell deterioration by HTLV-1 that can be therapeutically targeted.
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Hassan Z, Kumar ND, Reggiori F, Khan G. How Viruses Hijack and Modify the Secretory Transport Pathway. Cells 2021; 10:2535. [PMID: 34685515 PMCID: PMC8534161 DOI: 10.3390/cells10102535] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 08/28/2021] [Accepted: 09/06/2021] [Indexed: 12/23/2022] Open
Abstract
Eukaryotic cells contain dynamic membrane-bound organelles that are constantly remodeled in response to physiological and environmental cues. Key organelles are the endoplasmic reticulum, the Golgi apparatus and the plasma membrane, which are interconnected by vesicular traffic through the secretory transport route. Numerous viruses, especially enveloped viruses, use and modify compartments of the secretory pathway to promote their replication, assembly and cell egression by hijacking the host cell machinery. In some cases, the subversion mechanism has been uncovered. In this review, we summarize our current understanding of how the secretory pathway is subverted and exploited by viruses belonging to Picornaviridae, Coronaviridae, Flaviviridae,Poxviridae, Parvoviridae and Herpesviridae families.
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Affiliation(s)
- Zubaida Hassan
- Department of Medical Microbiology and Immunology, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain P.O. Box 17666, United Arab Emirates;
- Department of Microbiology, School of Life Sciences, Modibbo Adama University, Yola PMB 2076, Nigeria
| | - Nilima Dinesh Kumar
- Department of Biomedical Sciences of Cells and Systems, University of Groningen, University Medical Center Groningen, 9713 AV Groningen, The Netherlands; (N.D.K.); (F.R.)
- Department of Medical Microbiology and Infection Prevention, University of Groningen, University Medical Center Groningen, 9713 AV Groningen, The Netherlands
| | - Fulvio Reggiori
- Department of Biomedical Sciences of Cells and Systems, University of Groningen, University Medical Center Groningen, 9713 AV Groningen, The Netherlands; (N.D.K.); (F.R.)
| | - Gulfaraz Khan
- Department of Medical Microbiology and Immunology, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain P.O. Box 17666, United Arab Emirates;
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Xue J, Cheng J, Ma X, Shi Y, Yin H, Gao Y, Li J. Role of Ras-related Nuclear Protein/Polypyrimidine Tract Binding Protein in Facilitating the Replication of Hepatitis C Virus. J Clin Transl Hepatol 2021; 9:458-465. [PMID: 34447674 PMCID: PMC8369020 DOI: 10.14218/jcth.2020.00122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 02/16/2021] [Accepted: 03/11/2021] [Indexed: 12/04/2022] Open
Abstract
BACKGROUND AND AIMS Ras-related nuclear (RAN) protein is a small GTP-binding protein that is indispensable for the translocation of RNA and proteins through the nuclear pore complex. Recent studies have indicated that RAN plays an important role in virus infection. However, the role of RAN in hepatitis C virus (HCV) infection is unclear. The objective of this study was to investigate the role and underlying mechanisms of RAN in HCV infection. METHODS Huh7.5.1 cells were infected with the JC1-Luc virus for 24 h and then were incubated with complete medium for an additional 48 h. HCV infection and RAN expression were determined using luciferase assay, quantitative reverse transcription-PCR and western blotting. Small interfering RNA was used to silence RAN. Western blotting and immunofluorescence were used to evaluate the cytoplasmic translocation of polypyrimidine tract-binding (PTB), and coimmunoprecipitation was used to examine the interaction between RAN and PTB. RESULTS HCV infection significantly induced RAN expression and cytoplasmic redistribution of PTB. Knockdown of RAN dramatically inhibited HCV infection and the cytoplasmic accumulation of PTB. Colocalization of RAN and PTB was determined by immunofluorescence, and a direct interaction of RAN with PTB was demonstrated by coimmunoprecipitation. CONCLUSIONS PTB in the host cytoplasm is directly associated with HCV replication. These findings demonstrate that the involvement of RAN in HCV infection is mediated by influencing the cytoplasmic translocation of PTB.
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Affiliation(s)
- Jihua Xue
- Department of Infectious Diseases, The First Affiliated Hospital of Anhui Medical University, Hefei, Anhui, China
| | - Jun Cheng
- Department of Infectious Diseases, The First Affiliated Hospital of Anhui Medical University, Hefei, Anhui, China
| | - Xuejiao Ma
- Department of Infectious Diseases, The First Affiliated Hospital of Anhui Medical University, Hefei, Anhui, China
| | - Yixian Shi
- Department of Hepatology, Mengchao Hepatobiliary Hospital of Fujian Medical University, Fuzhou, Fujian, China
| | - Huafa Yin
- Department of Infectious Diseases, The First Affiliated Hospital of Anhui Medical University, Hefei, Anhui, China
| | - Yufeng Gao
- Department of Infectious Diseases, The First Affiliated Hospital of Anhui Medical University, Hefei, Anhui, China
- Correspondence to: Jiabin Li and Yufeng Gao, Department of Infectious Diseases, The First Affiliated Hospital of Anhui Medical University, No. 218, Jixi Road, Shushan District, Hefei, Anhui 230022, China. ORCID: https://orcid.org/0000-0002-6539-1802 (JL), https://orcid.org/0000-0003-1822-8161 (YG). Tel: +86-551-62923627, Fax: +86-551-62923617, E-mail: (JL) or Tel: +86-551-62922383, Fax: +86-551-62922096, E-mail: (YG)
| | - Jiabin Li
- Department of Infectious Diseases, The First Affiliated Hospital of Anhui Medical University, Hefei, Anhui, China
- Correspondence to: Jiabin Li and Yufeng Gao, Department of Infectious Diseases, The First Affiliated Hospital of Anhui Medical University, No. 218, Jixi Road, Shushan District, Hefei, Anhui 230022, China. ORCID: https://orcid.org/0000-0002-6539-1802 (JL), https://orcid.org/0000-0003-1822-8161 (YG). Tel: +86-551-62923627, Fax: +86-551-62923617, E-mail: (JL) or Tel: +86-551-62922383, Fax: +86-551-62922096, E-mail: (YG)
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Li HC, Yang CH, Lo SY. Cellular factors involved in the hepatitis C virus life cycle. World J Gastroenterol 2021; 27:4555-4581. [PMID: 34366623 PMCID: PMC8326260 DOI: 10.3748/wjg.v27.i28.4555] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 04/04/2021] [Accepted: 07/09/2021] [Indexed: 02/06/2023] Open
Abstract
The hepatitis C virus (HCV), an obligatory intracellular pathogen, highly depends on its host cells to propagate successfully. The HCV life cycle can be simply divided into several stages including viral entry, protein translation, RNA replication, viral assembly and release. Hundreds of cellular factors involved in the HCV life cycle have been identified over more than thirty years of research. Characterization of these cellular factors has provided extensive insight into HCV replication strategies. Some of these cellular factors are targets for anti-HCV therapies. In this review, we summarize the well-characterized and recently identified cellular factors functioning at each stage of the HCV life cycle.
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Affiliation(s)
- Hui-Chun Li
- Department of Biochemistry, Tzu Chi University, Hualien 970, Taiwan
| | - Chee-Hing Yang
- Department of Laboratory Medicine and Biotechnology, Tzu Chi University, Hualien 970, Taiwan
| | - Shih-Yen Lo
- Department of Laboratory Medicine and Biotechnology, Tzu Chi University, Hualien 970, Taiwan
- Department of Laboratory Medicine, Buddhist Tzu Chi General Hospital, Hualien 970, Taiwan
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Fenizia C, Ibba SV, Vanetti C, Strizzi S, Rossignol JF, Biasin M, Trabattoni D, Clerici M. The Modulation of Cholesterol Metabolism Is Involved in the Antiviral Effect of Nitazoxanide. Infect Dis Rep 2021; 13:636-644. [PMID: 34287319 PMCID: PMC8293206 DOI: 10.3390/idr13030060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 07/09/2021] [Accepted: 07/11/2021] [Indexed: 11/19/2022] Open
Abstract
We previously investigated the role of Nitazoxanide (NTZ), a thiazolide endowed with antiviral and antiparasitic activity, in HIV-1 infection. NTZ treatment in primary isolated PBMCs was able to reduce HIV-1 infection in vitro by inducing the expression of a number of type-I interferon-stimulated genes. Among them, NTZ was able to induce cholesterol-25-hydroxylase (CH25H), which is involved in cholesterol metabolism. In the present study, we wanted to deepen our knowledge about the antiviral mechanism of action of NTZ. Indeed, by inducing CH25H, which catalyzes the formation of 25-hydroxycholesterol from cholesterol, NTZ treatment repressed cholesterol biosynthetic pathways and promoted cholesterol mobilization and efflux from the cell. Such effects were even more pronounced upon stimulation with FLU antigens in combination. It is already well known how lipid metabolism and virus replication are tightly interconnected; thus, it is not surprising that the antiviral immune response employs genes related to cholesterol metabolism. Indeed, NTZ was able to modulate cholesterol metabolism in vitro and, by doing so, enhance the antiviral response. These results give us the chance to speculate about the suitability of NTZ as adjuvant for induction of specific natural immunity. Moreover, the putative application of NTZ to alimentary-related diseases should be investigated.
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Affiliation(s)
- Claudio Fenizia
- Department of Pathophysiology and Transplantation, University of Milan, Via F. Sforza 35, 20122 Milan, Italy; (C.F.); (C.V.)
- Department of Biomedical and Clinical Sciences, University of Milan, Via G.B. Grassi 74, 20157 Milan, Italy; (S.V.I.); (S.S.); (M.B.); (D.T.)
| | - Salomè Valentina Ibba
- Department of Biomedical and Clinical Sciences, University of Milan, Via G.B. Grassi 74, 20157 Milan, Italy; (S.V.I.); (S.S.); (M.B.); (D.T.)
| | - Claudia Vanetti
- Department of Pathophysiology and Transplantation, University of Milan, Via F. Sforza 35, 20122 Milan, Italy; (C.F.); (C.V.)
- Department of Biomedical and Clinical Sciences, University of Milan, Via G.B. Grassi 74, 20157 Milan, Italy; (S.V.I.); (S.S.); (M.B.); (D.T.)
| | - Sergio Strizzi
- Department of Biomedical and Clinical Sciences, University of Milan, Via G.B. Grassi 74, 20157 Milan, Italy; (S.V.I.); (S.S.); (M.B.); (D.T.)
| | | | - Mara Biasin
- Department of Biomedical and Clinical Sciences, University of Milan, Via G.B. Grassi 74, 20157 Milan, Italy; (S.V.I.); (S.S.); (M.B.); (D.T.)
| | - Daria Trabattoni
- Department of Biomedical and Clinical Sciences, University of Milan, Via G.B. Grassi 74, 20157 Milan, Italy; (S.V.I.); (S.S.); (M.B.); (D.T.)
| | - Mario Clerici
- Department of Pathophysiology and Transplantation, University of Milan, Via F. Sforza 35, 20122 Milan, Italy; (C.F.); (C.V.)
- IRCCS Fondazione Don Carlo Gnocchi, Via A. Capecelatro 66, 20148 Milan, Italy
- Correspondence: ; Tel.: +39-02-5031-9678
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Avula K, Singh B, Kumar PV, Syed GH. Role of Lipid Transfer Proteins (LTPs) in the Viral Life Cycle. Front Microbiol 2021; 12:673509. [PMID: 34248884 PMCID: PMC8260984 DOI: 10.3389/fmicb.2021.673509] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Accepted: 05/17/2021] [Indexed: 12/14/2022] Open
Abstract
Viruses are obligate parasites that depend on the host cell machinery for their replication and dissemination. Cellular lipids play a central role in multiple stages of the viral life cycle such as entry, replication, morphogenesis, and egress. Most viruses reorganize the host cell membranes for the establishment of viral replication complex. These specialized structures allow the segregation of replicating viral RNA from ribosomes and protect it from host nucleases. They also facilitate localized enrichment of cellular components required for viral replication and assembly. The specific composition of the lipid membrane governs its ability to form negative or positive curvature and possess a rigid or flexible form, which is crucial for membrane rearrangement and establishment of viral replication complexes. In this review, we highlight how different viruses manipulate host lipid transfer proteins and harness their functions to enrich different membrane compartments with specific lipids in order to facilitate multiple aspects of the viral life cycle.
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Affiliation(s)
- Kiran Avula
- Virus-Host Interaction Lab, Institute of Life Sciences, Bhubaneshwar, India.,Regional Centre for Biotechnology, Faridabad, India
| | - Bharati Singh
- Virus-Host Interaction Lab, Institute of Life Sciences, Bhubaneshwar, India.,School of Biotechnology, Kalinga Institute of Industrial Technology, Bhubaneshwar, India
| | - Preethy V Kumar
- Virus-Host Interaction Lab, Institute of Life Sciences, Bhubaneshwar, India.,School of Biotechnology, Kalinga Institute of Industrial Technology, Bhubaneshwar, India
| | - Gulam H Syed
- Virus-Host Interaction Lab, Institute of Life Sciences, Bhubaneshwar, India
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14
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Morita E, Suzuki Y. Membrane-Associated Flavivirus Replication Complex-Its Organization and Regulation. Viruses 2021; 13:v13061060. [PMID: 34205058 PMCID: PMC8228428 DOI: 10.3390/v13061060] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2021] [Revised: 06/02/2021] [Accepted: 06/02/2021] [Indexed: 02/07/2023] Open
Abstract
Flavivirus consists of a large number of arthropod-borne viruses, many of which cause life-threatening diseases in humans. A characteristic feature of flavivirus infection is to induce the rearrangement of intracellular membrane structure in the cytoplasm. This unique membranous structure called replication organelle is considered as a microenvironment that provides factors required for the activity of the flaviviral replication complex. The replication organelle serves as a place to coordinate viral RNA amplification, protein translation, and virion assembly and also to protect the viral replication complex from the cellular immune defense system. In this review, we summarize the current understanding of how the formation and function of membrane-associated flaviviral replication organelle are regulated by cellular factors.
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Affiliation(s)
- Eiji Morita
- Department of Biochemistry and Molecular Biology, Faculty of Agriculture and Life Science, Hirosaki University, 3 Bunkyo-cho, Hirosaki-shi 036-8561, Japan
- Correspondence: (E.M.); (Y.S.); Tel.: +81-172-39-3586 (E.M.); +81-72-684-7367 (Y.S.)
| | - Youichi Suzuki
- Department of Microbiology and Infection Control, Faculty of Medicine, Osaka Medical and Pharmaceutical University, 2-7 Daigaku-machi, Takatsuki 569-8686, Japan
- Correspondence: (E.M.); (Y.S.); Tel.: +81-172-39-3586 (E.M.); +81-72-684-7367 (Y.S.)
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15
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Ceramide and Related Molecules in Viral Infections. Int J Mol Sci 2021; 22:ijms22115676. [PMID: 34073578 PMCID: PMC8197834 DOI: 10.3390/ijms22115676] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 05/21/2021] [Accepted: 05/21/2021] [Indexed: 02/08/2023] Open
Abstract
Ceramide is a lipid messenger at the heart of sphingolipid metabolism. In concert with its metabolizing enzymes, particularly sphingomyelinases, it has key roles in regulating the physical properties of biological membranes, including the formation of membrane microdomains. Thus, ceramide and its related molecules have been attributed significant roles in nearly all steps of the viral life cycle: they may serve directly as receptors or co-receptors for viral entry, form microdomains that cluster entry receptors and/or enable them to adopt the required conformation or regulate their cell surface expression. Sphingolipids can regulate all forms of viral uptake, often through sphingomyelinase activation, and mediate endosomal escape and intracellular trafficking. Ceramide can be key for the formation of viral replication sites. Sphingomyelinases often mediate the release of new virions from infected cells. Moreover, sphingolipids can contribute to viral-induced apoptosis and morbidity in viral diseases, as well as virus immune evasion. Alpha-galactosylceramide, in particular, also plays a significant role in immune modulation in response to viral infections. This review will discuss the roles of ceramide and its related molecules in the different steps of the viral life cycle. We will also discuss how novel strategies could exploit these for therapeutic benefit.
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16
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Luquain-Costaz C, Rabia M, Hullin-Matsuda F, Delton I. Bis(monoacylglycero)phosphate, an important actor in the host endocytic machinery hijacked by SARS-CoV-2 and related viruses. Biochimie 2020; 179:247-256. [PMID: 33159981 PMCID: PMC7642752 DOI: 10.1016/j.biochi.2020.10.018] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 10/28/2020] [Accepted: 10/29/2020] [Indexed: 12/12/2022]
Abstract
Viruses, including the novel coronavirus SARS-CoV-2, redirect infected cell metabolism to their own purposes. After binding to its receptor angiotensin-converting enzyme 2 (ACE2) on the cell surface, the SARS-CoV-2 is taken up by receptor-mediated endocytosis ending in the acidic endolysosomal compartment. The virus hijacks the endosomal machinery leading to fusion of viral and endosomal membranes and release of the viral RNA into the cytosol. This mini-review specifically highlights the membrane lipid organization of the endosomal system focusing on the unconventional and late endosome/lysosome-specific phospholipid, bis(monoacylglycero)phosphate (BMP). BMP is enriched in alveolar macrophages of lung, one of the target tissue of SARS-CoV-2. This review details the BMP structure, its unsaturated fatty acid composition and fusogenic properties that are essential for the highly dynamic formation of the intraluminal vesicles inside the endosomes. Interestingly, BMP is necessary for infection and replication of enveloped RNA virus such as SARS-CoV-1 and Dengue virus. We also emphasize the role of BMP in lipid sorting and degradation, especially cholesterol transport in cooperation with Niemann Pick type C proteins (NPC 1 and 2) and with some oxysterol-binding protein (OSBP)-related proteins (ORPs) as well as in sphingolipid degradation. Interestingly, numerous virus infection required NPC1 as well as ORPs along the endocytic pathway. Furthermore, BMP content is increased during pathological endosomal lipid accumulation in various lysosomal storage disorders. This is particularly important knowing the high percentage of patients with metabolic disorders among the SARS-CoV-2 infected patients presenting severe forms of COVID-19.
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Affiliation(s)
- Céline Luquain-Costaz
- Univ-Lyon, CarMeN Laboratory, Inserm U1060, INRAe U1397, INSA Lyon, Villeurbanne, France
| | - Maxence Rabia
- Univ-Lyon, CarMeN Laboratory, Inserm U1060, INRAe U1397, INSA Lyon, Villeurbanne, France
| | | | - Isabelle Delton
- Univ-Lyon, CarMeN Laboratory, Inserm U1060, INRAe U1397, INSA Lyon, Villeurbanne, France.
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17
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Abstract
BACKGROUND 25-hydroxylase (CH25H) is an interferon-stimulated gene (ISG), which catalyzes the synthesis of 25-hydroxycholesterol (25HC). 25HC intervenes in metabolic and infectious processes and controls cholesterol homeostasis and influences viral entry into host cells. We verified whether natural resistance to HIV-1 infection in HIV-1-exposed seronegative (HESN) individuals is at least partially mediated by particularities in sterol biosynthesis. METHODS Peripheral blood mononuclear cells (PBMCs) and monocyte-derived macrophages (MDMs) isolated from 15 sexually exposed HESN and 15 healthy controls were in vitro HIV-1-infected and analyzed for: percentage of IFNα-producing plasmacytoid dendritic cells (pDCs); cholesterol signaling and inflammatory response RNA expression; resistance to HIV-1 infection. MDMs from five healthy controls were in vitro HIV-1-infected in the absence/presence of exogenously added 25HC. RESULTS IFNα-producing pDCs were augmented in HESN compared with healthy controls both in unstimulated and in in vitro HIV-1-infected PBMCs (P < 0.001). An increased expression of CH25H and of a number of genes involved in cholesterol metabolism (ABCA1, ABCG1, CYP7B1, LXRα, OSBP, PPARγ, SCARB1) was observed as well; this, was associated with a reduced susceptibility to in-vitro HIV-1-infection of PBMCs and MDMs (P < 0.01). Notably, addition of 25HC to MDMs resulted in increased cholesterol efflux and augmented resistance to in-vitro HIV-1-infection. CONCLUSION Results herein show that in HESN sterol metabolism might be particularly efficient. This could be related to the activation of the IFNα pathway and results into a reduced susceptibility to in-vitro HIV-1 infection. These results suggest a possible basis for therapeutic interventions to modulate HIV-1 infection.
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18
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Kolodziejek AM, Altura MA, Fan J, Petersen EM, Cook M, Brzovic PS, Miller SI. Salmonella Translocated Effectors Recruit OSBP1 to the Phagosome to Promote Vacuolar Membrane Integrity. Cell Rep 2020; 27:2147-2156.e5. [PMID: 31091452 DOI: 10.1016/j.celrep.2019.04.021] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Revised: 12/20/2018] [Accepted: 04/02/2019] [Indexed: 11/17/2022] Open
Abstract
Intracellular Salmonella use a type III secretion system (TTSS) to translocate effector proteins across the phagosome membrane and thus promote vacuole membrane tubulation, resulting in intracellular survival. This work demonstrates that the effector SseJ binds the eukaryotic lipid transporter oxysterol binding protein 1 (OSBP1). SseJ directs OSBP1 to the endosomal compartment in a manner dependent on the TTSS located on Salmonella pathogenicity island 2 (SPI2). OSBP1 localization is mediated by both SseJ and another OSBP1-binding SPI2 translocated effector, the deubiquitinase SseL. Deletion of both SseJ and SseL reduced vacuolar integrity with increased bacteria released into the eukaryotic cytoplasm of epithelial cells, indicating that their combined activities are necessary for vacuole membrane stability. Cells knocked down for OSBP1 or deleted for the OSBP1-binding proteins VAPA/B also demonstrate loss of vacuole integrity, consistent with the hypothesis that OSBP1 recruitment is required for SPI2-mediated alterations that promote vacuolar integrity of salmonellae.
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Affiliation(s)
- Anna M Kolodziejek
- Department of Microbiology, University of Washington, Seattle, WA 98195, USA
| | - Melissa A Altura
- Department of Microbiology, University of Washington, Seattle, WA 98195, USA
| | - Junping Fan
- Department of Microbiology, University of Washington, Seattle, WA 98195, USA
| | - Erik M Petersen
- Department of Microbiology, University of Washington, Seattle, WA 98195, USA
| | - Matthew Cook
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
| | - Peter S Brzovic
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
| | - Samuel I Miller
- Department of Microbiology, University of Washington, Seattle, WA 98195, USA; Department of Immunology, University of Washington, Seattle, WA 98195, USA; Department of Medicine, University of Washington, Seattle, WA 98195, USA; Department of Genome Sciences, University of Washington, Seattle, WA 98195, USA.
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19
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Bagchi P. Endoplasmic reticulum in viral infection. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2019; 350:265-284. [PMID: 32138901 DOI: 10.1016/bs.ircmb.2019.10.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Virus exploits host cellular machinery to replicate and form new viral progeny and endoplasmic reticulum (ER) plays central role in the interplay between virus and host cell. Here I will discuss how cellular functions of ER being utilized by viruses from different families during different stages of pathogenesis. Flow of knowledge related to this area of research based on interdisciplinary approach, using biochemical and cell biological assays coupled with advanced microscopy strategies, is pushing our understanding of the virus-ER interaction during infection to the next level.
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Affiliation(s)
- Parikshit Bagchi
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI, United States.
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20
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Nir2 Is an Effector of VAPs Necessary for Efficient Hepatitis C Virus Replication and Phosphatidylinositol 4-Phosphate Enrichment at the Viral Replication Organelle. J Virol 2019; 93:JVI.00742-19. [PMID: 31484747 DOI: 10.1128/jvi.00742-19] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Accepted: 08/28/2019] [Indexed: 01/19/2023] Open
Abstract
The endoplasmic reticulum (ER)-resident proteins vesicle-associated membrane protein (VAMP)-associated protein A and B (VAPA and VAPB) have been reported to be necessary for efficient hepatitis C virus (HCV) replication, but the specific mechanisms are not well understood. VAPs are known to recruit lipid transfer proteins to the ER, including oxysterol binding protein (OSBP), which has been previously shown to be necessary for cholesterol delivery to the HCV replication organelle in exchange for phosphatidylinositol 4-phosphate [PI(4)P]. Here, we show that VAPA and VAPB are redundant for HCV infection and that dimerization is not required for their function. In addition, we identify the phosphatidylinositol transfer protein Nir2 as an effector of VAPs to support HCV replication. We propose that Nir2 functions to replenish phosphoinositides at the HCV replication organelle to maintain elevated steady-state levels of PI(4)P, which is removed by OSBP. Thus, Nir2, along with VAPs, OSBP, and the phosphatidylinositol 4-kinase, completes a cycle of phosphoinositide flow between the ER and viral replication organelles to drive ongoing viral replication.IMPORTANCE Hepatitis C virus (HCV) is known for its ability to modulate phosphoinositide signaling pathways for its replication. Elevated levels of phosphatidylinositol 4-phosphate [PI(4)P] in HCV replication organelles (ROs) recruits lipid transfer proteins (LTPs), like oxysterol-binding protein (OSBP). OSBP exchanges PI(4)P with cholesterol, thus removing PI(4)P from the HCV RO. Here, we found that the phosphatidylinositol transfer protein Nir2 acts as an LTP and may replenish PI at the HCV RO by interacting with VAMP-associated proteins (VAPs), enabling continuous viral replication during chronic infection. Therefore, the coordination of OSBP, Nir2, and VAPs completes our understanding of the phosphoinositide cycle between the ER and HCV ROs.
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21
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Roberts BL, Severance ZC, Bensen RC, Le-McClain AT, Malinky CA, Mettenbrink EM, Nuñez JI, Reddig WJ, Blewett EL, Burgett AWG. Differing activities of oxysterol-binding protein (OSBP) targeting anti-viral compounds. Antiviral Res 2019; 170:104548. [PMID: 31271764 PMCID: PMC10786240 DOI: 10.1016/j.antiviral.2019.104548] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Revised: 06/25/2019] [Accepted: 06/29/2019] [Indexed: 11/27/2022]
Abstract
Oxysterol-binding Protein (OSBP) is a human lipid-transport protein required for the cellular replication of many types of viruses, including several human pathogens. The structurally-diverse small molecule compounds OSW-1, itraconazole (ITZ), T-00127-HEV2 (THEV) and TTP-8307 (TTP) inhibit viral replication through interaction with the OSBP protein. The OSW-1 compound reduces intracellular OSBP, and the reduction of OSBP protein levels persists multiple days after the OSW-1-compound treatment is stopped. The OSW-1-induced reduction of OSBP levels inhibited Enterovirus replication prophylactically in cells. In this report, the OSBP-interacting compounds ITZ, THEV, and TTP are shown not to reduce OSBP levels in cells, unlike the OSW-1-compound, and the OSW-1 compound is determined to be the only compound capable of providing prophylactic antiviral activity in cells. Furthermore, OSW-1 and THEV inhibit the binding of 25-hydroxycholesterol (25-OHC) to OSBP indicating that these compounds bind at the conserved sterol ligand binding site. The ITZ and TTP compounds do not inhibit 25-hydroxycholesterol binding to OSBP, and therefore ITZ and TTP interact with OSBP through other, unidentified binding sites. Co-administration of the THEV compound partially blocks the cellular activity of OSW-1, including the reduction of cellular OSBP protein levels; co-administration of the ITZ and TTP compounds have minimal effect on OSW-1 cellular activity further supporting different modes of interaction with these compounds to OSBP. OSW-1, ITZ, THEV, and TTP treatment alter OSBP cellular localization and levels, but in four distinct ways. Co-administration of OSW-1 and ITZ induced OSBP cellular localization patterns with features similar to the effects of ITZ and OSW-1 treatment alone. Based on these results, OSBP is capable of interacting with multiple structural classes of antiviral small molecule compounds at different binding sites, and the different compounds have distinct effects on OSBP cellular activity.
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Affiliation(s)
- Brett L Roberts
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK, United States
| | - Zachary C Severance
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK, United States
| | - Ryan C Bensen
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK, United States
| | - Anh T Le-McClain
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK, United States
| | - Cori A Malinky
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK, United States
| | - Evan M Mettenbrink
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK, United States
| | - Juan I Nuñez
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK, United States
| | - William J Reddig
- Department of Biochemistry and Microbiology, Oklahoma State University Center for Health Sciences, Tulsa, OK, United States
| | - Earl L Blewett
- Department of Biochemistry and Microbiology, Oklahoma State University Center for Health Sciences, Tulsa, OK, United States
| | - Anthony W G Burgett
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK, United States.
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22
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Zhang Z, He G, Filipowicz NA, Randall G, Belov GA, Kopek BG, Wang X. Host Lipids in Positive-Strand RNA Virus Genome Replication. Front Microbiol 2019; 10:286. [PMID: 30863375 PMCID: PMC6399474 DOI: 10.3389/fmicb.2019.00286] [Citation(s) in RCA: 78] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Accepted: 02/04/2019] [Indexed: 12/19/2022] Open
Abstract
Membrane association is a hallmark of the genome replication of positive-strand RNA viruses [(+)RNA viruses]. All well-studied (+)RNA viruses remodel host membranes and lipid metabolism through orchestrated virus-host interactions to create a suitable microenvironment to survive and thrive in host cells. Recent research has shown that host lipids, as major components of cellular membranes, play key roles in the replication of multiple (+)RNA viruses. This review focuses on how (+)RNA viruses manipulate host lipid synthesis and metabolism to facilitate their genomic RNA replication, and how interference with the cellular lipid metabolism affects viral replication.
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Affiliation(s)
- Zhenlu Zhang
- National Key Laboratory of Crop Biology, National Research Center for Apple Engineering and Technology, College of Horticulture Science and Engineering, Shandong Agricultural University, Tai'an, China
- School of Plant and Environmental Sciences, Virginia Tech, Blacksburg, VA, United States
| | - Guijuan He
- School of Plant and Environmental Sciences, Virginia Tech, Blacksburg, VA, United States
- Fujian Province Key Laboratory of Plant Virology, Institute of Plant Virology, Fujian Agriculture and Forestry University, Fuzhou, China
| | | | - Glenn Randall
- Department of Microbiology, The University of Chicago, Chicago, IL, United States
| | - George A. Belov
- Virginia-Maryland Regional College of Veterinary Medicine, University of Maryland, College Park, MD, United States
| | | | - Xiaofeng Wang
- School of Plant and Environmental Sciences, Virginia Tech, Blacksburg, VA, United States
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23
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Roberts BL, Severance ZC, Bensen RC, Le AT, Kothapalli NR, Nuñez JI, Ma H, Wu S, Standke SJ, Yang Z, Reddig WJ, Blewett EL, Burgett AWG. Transient Compound Treatment Induces a Multigenerational Reduction of Oxysterol-Binding Protein (OSBP) Levels and Prophylactic Antiviral Activity. ACS Chem Biol 2019; 14:276-287. [PMID: 30576108 PMCID: PMC6379863 DOI: 10.1021/acschembio.8b00984] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
![]()
Oxysterol-binding
protein (OSBP) is a lipid transport and regulatory
protein required for the replication of Enterovirus genus viruses, which includes many significant human pathogens.
Short-term exposure (i.e., 1–6 h) to a low dose (i.e., 1 nM)
of the natural product compound OSW-1 induces a reduction of cellular
OSBP levels by ∼90% in multiple different cell lines with no
measurable cytotoxicity, defect in cellular proliferation, or global
proteome reduction. Interestingly, the reduction of OSBP levels persists
multiple days after the low-dose, transient OSW-1 compound treatment
is ended and the intracellular OSW-1 compound levels drop to undetectable
levels. The reduction in OSBP levels is inherited in multiple generations
of cells that are propagated after the OSW-1 compound treatment is
stopped. The enduring multiday, multigenerational reduction of OSBP
levels triggered by the OSW-1 compound is not due to proteasome degradation
of OSBP or due to a reduction in OSBP mRNA levels. OSW-1 compound
treatment induces transient autophagy in cells, but blocking autophagy
does not rescue OSBP levels. Although the specific cellular mechanism
of long-term OSBP repression is not yet identified, these results
clearly show the existence of an OSBP specific cellular regulation
process that is triggered upon treatment with an OSBP-binding compound.
The stable reduction of OSBP levels upon short-term, transient OSW-1
compound treatment will be a powerful tool to understand OSBP regulation
and cellular function. Additionally, the persistent reduction in OSBP
levels triggered by the transient OSW-1 compound treatment substantially
reduces viral replication in treated cells. Therefore, the long-term,
compound-induced reduction of OSBP in cells presents a new route to
broad spectrum anti-Enterovirus activity, including
as a novel route to antiviral prophylactic treatment through small
molecule targeting a human host protein.
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Affiliation(s)
- Brett L. Roberts
- Department of Chemistry and Biochemistry, The University of Oklahoma, 101 Stephenson Parkway, Norman, Oklahoma 73019, United States
| | - Zachary C. Severance
- Department of Chemistry and Biochemistry, The University of Oklahoma, 101 Stephenson Parkway, Norman, Oklahoma 73019, United States
| | - Ryan C. Bensen
- Department of Chemistry and Biochemistry, The University of Oklahoma, 101 Stephenson Parkway, Norman, Oklahoma 73019, United States
| | - Anh T. Le
- Department of Chemistry and Biochemistry, The University of Oklahoma, 101 Stephenson Parkway, Norman, Oklahoma 73019, United States
| | - Naga Rama Kothapalli
- Department of Chemistry and Biochemistry, The University of Oklahoma, 101 Stephenson Parkway, Norman, Oklahoma 73019, United States
| | - Juan I. Nuñez
- Department of Chemistry and Biochemistry, The University of Oklahoma, 101 Stephenson Parkway, Norman, Oklahoma 73019, United States
| | - Hongyan Ma
- Department of Chemistry and Biochemistry, The University of Oklahoma, 101 Stephenson Parkway, Norman, Oklahoma 73019, United States
| | - Si Wu
- Department of Chemistry and Biochemistry, The University of Oklahoma, 101 Stephenson Parkway, Norman, Oklahoma 73019, United States
| | - Shawna J. Standke
- Department of Chemistry and Biochemistry, The University of Oklahoma, 101 Stephenson Parkway, Norman, Oklahoma 73019, United States
| | - Zhibo Yang
- Department of Chemistry and Biochemistry, The University of Oklahoma, 101 Stephenson Parkway, Norman, Oklahoma 73019, United States
| | - William J. Reddig
- Department of Biochemistry and Microbiology, Oklahoma State University Center for Health Sciences, 1111 West 17th Street, Tulsa, Oklahoma 74107, United States
| | - Earl L. Blewett
- Department of Biochemistry and Microbiology, Oklahoma State University Center for Health Sciences, 1111 West 17th Street, Tulsa, Oklahoma 74107, United States
| | - Anthony W. G. Burgett
- Department of Chemistry and Biochemistry, The University of Oklahoma, 101 Stephenson Parkway, Norman, Oklahoma 73019, United States
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24
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Sharma G, Raheja H, Das S. Hepatitis C virus: Enslavement of host factors. IUBMB Life 2018; 70:41-49. [PMID: 29281185 DOI: 10.1002/iub.1702] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Revised: 11/20/2017] [Accepted: 11/28/2017] [Indexed: 12/11/2022]
Abstract
Hepatitis C virus (HCV) has infected over 170 million people world-wide. This infection causes severe liver damage that can progress to hepatocellular carcinoma leading to death of the infected patients. Development of a cell culture model system for the study of HCV infection in the recent past has helped the researchers world-wide to understand the biology of this virus. Studies over the past decade have revealed the tricks played by the virus to sustain itself, for as long as 40 years, in the host setup without being eliminated by the immune system. Today we understand that the host organelles and different cellular proteins are affected during HCV infection. This cytoplasmic virus has all the cellular organelles at its disposal to successfully replicate, from ribosomes and intracellular membranous structures to the nucleus. It modulates these organelles at both the structural and the functional levels. The vast knowledge about the viral genome and viral proteins has also helped in the development of drugs against the virus. Despite the achieved success rate to cure the infected patients, we struggle to eliminate the cases of recurrence and the non-responders. Such cases might emerge owing to the property of the viral genome to accumulate mutations during its succeeding replication cycles which favours its survival. The current situation calls an urgent need for alternate therapeutic strategies to counter this major problem of human health. © 2017 IUBMB Life, 70(1):41-49, 2018.
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Affiliation(s)
- Geetika Sharma
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, 560012, Karnataka, India
| | - Harsha Raheja
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, 560012, Karnataka, India
| | - Saumitra Das
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, 560012, Karnataka, India
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25
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Robinson M, Schor S, Barouch-Bentov R, Einav S. Viral journeys on the intracellular highways. Cell Mol Life Sci 2018; 75:3693-3714. [PMID: 30043139 PMCID: PMC6151136 DOI: 10.1007/s00018-018-2882-0] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Revised: 07/01/2018] [Accepted: 07/19/2018] [Indexed: 12/24/2022]
Abstract
Viruses are obligate intracellular pathogens that are dependent on cellular machineries for their replication. Recent technological breakthroughs have facilitated reliable identification of host factors required for viral infections and better characterization of the virus-host interplay. While these studies have revealed cellular machineries that are uniquely required by individual viruses, accumulating data also indicate the presence of broadly required mechanisms. Among these overlapping cellular functions are components of intracellular membrane trafficking pathways. Here, we review recent discoveries focused on how viruses exploit intracellular membrane trafficking pathways to promote various stages of their life cycle, with an emphasis on cellular factors that are usurped by a broad range of viruses. We describe broadly required components of the endocytic and secretory pathways, the Endosomal Sorting Complexes Required for Transport pathway, and the autophagy pathway. Identification of such overlapping host functions offers new opportunities to develop broad-spectrum host-targeted antiviral strategies.
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Affiliation(s)
- Makeda Robinson
- Division of Infectious Diseases and Geographic Medicine, Department of Medicine, Stanford University School of Medicine, 300 Pasteur Drive, Lane Building, Rm L127, Stanford, CA, 94305, USA
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA, USA
| | - Stanford Schor
- Division of Infectious Diseases and Geographic Medicine, Department of Medicine, Stanford University School of Medicine, 300 Pasteur Drive, Lane Building, Rm L127, Stanford, CA, 94305, USA
| | - Rina Barouch-Bentov
- Division of Infectious Diseases and Geographic Medicine, Department of Medicine, Stanford University School of Medicine, 300 Pasteur Drive, Lane Building, Rm L127, Stanford, CA, 94305, USA
| | - Shirit Einav
- Division of Infectious Diseases and Geographic Medicine, Department of Medicine, Stanford University School of Medicine, 300 Pasteur Drive, Lane Building, Rm L127, Stanford, CA, 94305, USA.
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA, USA.
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Rahamathulla S, Ratnagiri BSVV, Manickam M, Sultana S, Mamatha DM, Magisetty O, Nagarapu R, Ponamgi SPD. Determination of Sustained Virological Response in Hepatitis C Virus Genotypes by the Number of Mutations in the E2 and NS5A-ISDR Regions: A Meta-Analysis. RUSS J GENET+ 2018. [DOI: 10.1134/s1022795418090119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Pietrangelo A, Ridgway ND. Bridging the molecular and biological functions of the oxysterol-binding protein family. Cell Mol Life Sci 2018; 75:3079-3098. [PMID: 29536114 PMCID: PMC11105248 DOI: 10.1007/s00018-018-2795-y] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Revised: 02/18/2018] [Accepted: 03/07/2018] [Indexed: 12/19/2022]
Abstract
Oxysterol-binding protein (OSBP) and OSBP-related proteins (ORPs) constitute a large eukaryotic gene family that transports and regulates the metabolism of sterols and phospholipids. The original classification of the family based on oxysterol-binding activity belies the complex dual lipid-binding specificity of the conserved OSBP homology domain (OHD). Additional protein- and membrane-interacting modules mediate the targeting of select OSBP/ORPs to membrane contact sites between organelles, thus positioning the OHD between opposing membranes for lipid transfer and metabolic regulation. This unique subcellular location, coupled with diverse ligand preferences and tissue distribution, has identified OSBP/ORPs as key arbiters of membrane composition and function. Here, we will review how molecular models of OSBP/ORP-mediated intracellular lipid transport and regulation at membrane contact sites relate to their emerging roles in cellular and organismal functions.
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Affiliation(s)
- Antonietta Pietrangelo
- Atlantic Research Center, C306 CRC Bldg, Department of Pediatrics, and Biochemistry and Molecular Biology, Dalhousie University, 5849 University Av., Halifax, NS, B3H4R2, Canada
| | - Neale D Ridgway
- Atlantic Research Center, C306 CRC Bldg, Department of Pediatrics, and Biochemistry and Molecular Biology, Dalhousie University, 5849 University Av., Halifax, NS, B3H4R2, Canada.
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Meutiawati F, Bezemer B, Strating JRPM, Overheul GJ, Žusinaite E, van Kuppeveld FJM, van Cleef KWR, van Rij RP. Posaconazole inhibits dengue virus replication by targeting oxysterol-binding protein. Antiviral Res 2018; 157:68-79. [PMID: 29981375 DOI: 10.1016/j.antiviral.2018.06.017] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Revised: 06/08/2018] [Accepted: 06/30/2018] [Indexed: 11/30/2022]
Abstract
Dengue virus (DENV) is associated with an estimated 390 million infections per year, occurring across approximately 100 countries in tropical and sub-tropical regions. To date, there are no antiviral drugs or specific therapies to treat DENV infection. Posaconazole and itraconazole are potent antifungal drugs that inhibit ergosterol biosynthesis in fungal cells, but also target a number of human proteins. Here, we show that itraconazole and posaconazole have antiviral activity against DENV. Posaconazole inhibited replication of multiple serotypes of DENV and the related flavivirus Zika virus, and reduced viral RNA replication, but not translation of the viral genome. We used a combination of knockdown and drug sensitization assays to define the molecular target of posaconazole that mediates its antiviral activity. We found that knockdown of oxysterol-binding protein (OSBP) inhibited DENV replication. Moreover, knockdown of OSBP, but not other known targets of posaconazole, enhanced the inhibitory effect of posaconazole. Our findings imply OSBP as a potential target for the development of antiviral compounds against DENV.
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Affiliation(s)
- Febrina Meutiawati
- Department of Medical Microbiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands; Radboudumc Center for Infectious Diseases, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Bodine Bezemer
- Department of Medical Microbiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands; Radboudumc Center for Infectious Diseases, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Jeroen R P M Strating
- Virology Division, Department of Infectious Diseases & Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - Gijs J Overheul
- Department of Medical Microbiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands; Radboudumc Center for Infectious Diseases, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Eva Žusinaite
- Institute of Technology, University of Tartu, Tartu, Estonia
| | - Frank J M van Kuppeveld
- Virology Division, Department of Infectious Diseases & Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - Koen W R van Cleef
- Department of Medical Microbiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands; Radboudumc Center for Infectious Diseases, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Ronald P van Rij
- Department of Medical Microbiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands; Radboudumc Center for Infectious Diseases, Radboud University Medical Center, Nijmegen, The Netherlands.
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Hacker B, Schultheiß C, Döring M, Kurzik-Dumke U. Molecular partners of hNOT/ALG3, the human counterpart of the Drosophila NOT and yeast ALG3 gene, suggest its involvement in distinct cellular processes relevant to congenital disorders of glycosylation, cancer, neurodegeneration and a variety of further pathologies. Hum Mol Genet 2018; 27:1858-1878. [DOI: 10.1093/hmg/ddy087] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Accepted: 03/06/2018] [Indexed: 01/04/2023] Open
Affiliation(s)
- Benedikt Hacker
- Laboratory for Comparative Tumour Biology, Institute of Medical Microbiology and Hygiene, University Medical Centre, Johannes Gutenberg University, 55131 Mainz, Germany
| | - Christoph Schultheiß
- Laboratory for Comparative Tumour Biology, Institute of Medical Microbiology and Hygiene, University Medical Centre, Johannes Gutenberg University, 55131 Mainz, Germany
| | - Michael Döring
- Laboratory for Comparative Tumour Biology, Institute of Medical Microbiology and Hygiene, University Medical Centre, Johannes Gutenberg University, 55131 Mainz, Germany
| | - Ursula Kurzik-Dumke
- Laboratory for Comparative Tumour Biology, Institute of Medical Microbiology and Hygiene, University Medical Centre, Johannes Gutenberg University, 55131 Mainz, Germany
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Hepatitis C Virus Replication Depends on Endosomal Cholesterol Homeostasis. J Virol 2017; 92:JVI.01196-17. [PMID: 29046459 DOI: 10.1128/jvi.01196-17] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Accepted: 09/28/2017] [Indexed: 01/16/2023] Open
Abstract
Similar to other positive-strand RNA viruses, hepatitis C virus (HCV) causes massive rearrangements of intracellular membranes, resulting in a membranous web (MW) composed of predominantly double-membrane vesicles (DMVs), the presumed sites of RNA replication. DMVs are enriched for cholesterol, but mechanistic details on the source and recruitment of cholesterol to the viral replication organelle are only partially known. Here we focused on selected lipid transfer proteins implicated in direct lipid transfer at various endoplasmic reticulum (ER)-membrane contact sites. RNA interference (RNAi)-mediated knockdown identified several hitherto unknown HCV dependency factors, such as steroidogenic acute regulatory protein-related lipid transfer domain protein 3 (STARD3), oxysterol-binding protein-related protein 1A and -B (OSBPL1A and -B), and Niemann-Pick-type C1 (NPC1), all residing at late endosome and lysosome membranes and required for efficient HCV RNA replication but not for replication of the closely related dengue virus. Focusing on NPC1, we found that knockdown or pharmacological inhibition caused cholesterol entrapment in lysosomal vesicles concomitant with decreased cholesterol abundance at sites containing the viral replicase factor NS5A. In untreated HCV-infected cells, unesterified cholesterol accumulated at the perinuclear region, partially colocalizing with NS5A at DMVs, arguing for NPC1-mediated endosomal cholesterol transport to the viral replication organelle. Consistent with cholesterol being an important structural component of DMVs, reducing NPC1-dependent endosomal cholesterol transport impaired MW integrity. This suggests that HCV usurps lipid transfer proteins, such as NPC1, at ER-late endosome/lysosome membrane contact sites to recruit cholesterol to the viral replication organelle, where it contributes to MW functionality.IMPORTANCE A key feature of the replication of positive-strand RNA viruses is the rearrangement of the host cell endomembrane system to produce a membranous replication organelle (RO). The underlying mechanisms are far from being elucidated fully. In this report, we provide evidence that HCV RNA replication depends on functional lipid transport along the endosomal-lysosomal pathway that is mediated by several lipid transfer proteins, such as the Niemann-Pick type C1 (NPC1) protein. Pharmacological inhibition of NPC1 function reduced viral replication, impaired the transport of cholesterol to the viral replication organelle, and altered organelle morphology. Besides NPC1, our study reports the importance of additional endosomal and lysosomal lipid transfer proteins required for viral replication, thus contributing to our understanding of how HCV manipulates their function in order to generate a membranous replication organelle. These results might have implications for the biogenesis of replication organelles of other positive-strand RNA viruses.
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Phosphorylation of Serine 225 in Hepatitis C Virus NS5A Regulates Protein-Protein Interactions. J Virol 2017; 91:JVI.00805-17. [PMID: 28615203 PMCID: PMC5553161 DOI: 10.1128/jvi.00805-17] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Accepted: 06/03/2017] [Indexed: 12/31/2022] Open
Abstract
Hepatitis C virus (HCV) nonstructural protein 5A (NS5A) is a phosphoprotein that plays key, yet poorly defined, roles in both virus genome replication and virion assembly/release. It has been proposed that differential phosphorylation could act as a switch to regulate the various functions of NS5A; however, the mechanistic details of the role of this posttranslational modification in the virus life cycle remain obscure. We previously reported (D. Ross-Thriepland, J. Mankouri, and M. Harris, J Virol 89:3123–3135, 2015, doi:10.1128/JVI.02995-14) a role for phosphorylation at serine 225 (S225) of NS5A in the regulation of JFH-1 (genotype 2a) genome replication. A phosphoablatant (S225A) mutation resulted in a 10-fold reduction in replication and a perinuclear restricted distribution of NS5A, whereas the corresponding phosphomimetic mutation (S225D) had no phenotype. To determine the molecular mechanisms underpinning this phenotype we conducted a label-free proteomics approach to identify cellular NS5A interaction partners. This analysis revealed that the S225A mutation disrupted the interactions of NS5A with a number of cellular proteins, in particular the nucleosome assembly protein 1-like protein 1 (NAP1L1), bridging integrator 1 (Bin1, also known as amphiphysin II), and vesicle-associated membrane protein-associated protein A (VAP-A). These interactions were validated by immunoprecipitation/Western blotting, immunofluorescence, and proximity ligation assay. Importantly, small interfering RNA (siRNA)-mediated knockdown of NAP1L1, Bin1 or VAP-A impaired viral genome replication and recapitulated the perinuclear redistribution of NS5A seen in the S225A mutant. These results demonstrate that S225 phosphorylation regulates the interactions of NS5A with a defined subset of cellular proteins. Furthermore, these interactions regulate both HCV genome replication and the subcellular localization of replication complexes. IMPORTANCE Hepatitis C virus is an important human pathogen. The viral nonstructural 5A protein (NS5A) is the target for new antiviral drugs. NS5A has multiple functions during the virus life cycle, but the biochemical details of these roles remain obscure. NS5A is known to be phosphorylated by cellular protein kinases, and in this study, we set out to determine whether this modification is required for the binding of NS5A to other cellular proteins. We identified 3 such proteins and show that they interacted only with NS5A that was phosphorylated on a specific residue. Furthermore, these proteins were required for efficient virus replication and the ability of NS5A to spread throughout the cytoplasm of the cell. Our results help to define the function of NS5A and may contribute to an understanding of the mode of action of the highly potent antiviral drugs that are targeted to NS5A.
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Pirro M, Bianconi V, Francisci D, Schiaroli E, Bagaglia F, Sahebkar A, Baldelli F. Hepatitis C virus and proprotein convertase subtilisin/kexin type 9: a detrimental interaction to increase viral infectivity and disrupt lipid metabolism. J Cell Mol Med 2017; 21:3150-3161. [PMID: 28722331 PMCID: PMC5706572 DOI: 10.1111/jcmm.13273] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Accepted: 05/07/2017] [Indexed: 12/21/2022] Open
Abstract
From viral binding to the hepatocyte surface to extracellular virion release, the replication cycle of the hepatitis C virus (HCV) intersects at various levels with lipid metabolism; this leads to a derangement of the lipid profile and to increased viral infectivity. Accumulating evidence supports the crucial regulatory role of proprotein convertase subtilisin/kexin type 9 (PCSK9) in lipoprotein metabolism. Notably, a complex interaction between HCV and PCSK9 has been documented. Indeed, either increased or reduced circulating PCSK9 levels have been observed in HCV patients; this discrepancy might be related to several confounders, including HCV genotype, human immunodeficiency virus (HIV) coinfection and the ambiguous HCV‐mediated influence on PCSK9 transcription factors. On the other hand, PCSK9 may itself influence HCV infectivity, inasmuch as the expression of different hepatocyte surface entry proteins and receptors is regulated by PCSK9. The aim of this review is to summarize the current evidence about the complex interaction between HCV and liver lipoprotein metabolism, with a specific focus on PCSK9. The underlying assumption of this review is that the interconnections between HCV and PCSK9 may be central to explain viral infectivity.
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Affiliation(s)
- Matteo Pirro
- Unit of Internal Medicine, Department of Medicine, University of Perugia, Perugia, Italy
| | - Vanessa Bianconi
- Unit of Internal Medicine, Department of Medicine, University of Perugia, Perugia, Italy
| | - Daniela Francisci
- Unit of Infectious Diseases, Department of Medicine, University of Perugia, Perugia, Italy
| | - Elisabetta Schiaroli
- Unit of Infectious Diseases, Department of Medicine, University of Perugia, Perugia, Italy
| | - Francesco Bagaglia
- Unit of Internal Medicine, Department of Medicine, University of Perugia, Perugia, Italy
| | - Amirhossein Sahebkar
- Biotechnology Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Franco Baldelli
- Unit of Infectious Diseases, Department of Medicine, University of Perugia, Perugia, Italy
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Wang H, Tai AW. Continuous de novo generation of spatially segregated hepatitis C virus replication organelles revealed by pulse-chase imaging. J Hepatol 2017; 66:55-66. [PMID: 27599826 PMCID: PMC5167665 DOI: 10.1016/j.jhep.2016.08.018] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Revised: 08/22/2016] [Accepted: 08/26/2016] [Indexed: 01/22/2023]
Abstract
BACKGROUND & AIMS Like all positive-sense RNA viruses, hepatitis C virus (HCV) induces host membrane alterations for its replication. In chronically infected cells, it is not known whether these viral replication organelles are being continually resupplied by newly synthesized viral proteins in situ, or whether they are generated de novo. Here we aimed to study temporal events in replication organelles formation and maturation. METHODS Here we use pulse-chase labeling in combination with confocal microscopy, correlative light electron microscopy and biochemical methods to identify temporally distinct populations of replication organelles in living cells and study the formation, morphogenesis as well as compositional and functional changes of replication organelles over time. RESULTS We found that HCV replication organelles are continuously generated de novo at spatially distinct sites from preformed ones. This process is accompanied by accumulated intracellular membrane alteration, increased cholesterol delivery, NS5A phosphorylation, and positive-strand RNA content, and by eventual association with HCV core protein around lipid droplets. Generation of spatially segregated foci requires viral NS5A and the host factors phosphatidylinositol 4-kinase and oxysterol-binding protein, while association of foci with lipid droplets requires cholesterol. CONCLUSIONS Our results reveal that HCV replication organelles are not static structures, but instead are continuously generated and dynamically change in composition and possibly also in function. LAY SUMMARY Hepatitis C virus replication membrane structures are continuously generated at spatially distinct sites. New replication organelles are different in composition, and possibly also in function, compared to old replication organelles.
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Affiliation(s)
- Hongliang Wang
- Division of Gastroenterology, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan
| | - Andrew W. Tai
- Division of Gastroenterology, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan
,Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan
,Medicine Service, Ann Arbor Veterans Administration Health System, Ann Arbor, Michigan
,Correspondence: Andrew W. Tai, University of Michigan, 6520 MSRB I SPC 5682, 1150 W Medical Center Dr, Ann Arbor, MI 48109-5682, Tel: (734) 764-2804, FAX: (734) 763-2535,
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Miyamura T, Lemon SM, Walker CM, Wakita T. The HCV Replicase Complex and Viral RNA Synthesis. HEPATITIS C VIRUS I 2016. [PMCID: PMC7122888 DOI: 10.1007/978-4-431-56098-2_8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Replication of hepatitis C virus (HCV) is tightly linked to membrane alterations designated the membranous web, harboring the viral replicase complex. In this chapter we describe the morphology and 3D architecture of the HCV-induced replication organelles, mainly consisting of double membrane vesicles, which are generated by a concerted action of the nonstructural proteins NS3 to NS5B. Recent studies have furthermore identified a number of host cell proteins and lipids contributing to the biogenesis of the membranous web, which are discussed in this chapter. Viral RNA synthesis is tightly associated with these membrane alterations and mainly driven by the viral RNA dependent RNA polymerase NS5B. We summarize our current knowledge of the structure and function of NS5B, the role of cis-acting replication elements at the termini of the genome in regulating RNA synthesis and the contribution of additional viral and host factors to viral RNA synthesis, which is still ill defined.
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Affiliation(s)
- Tatsuo Miyamura
- National Institute of Infectious Diseases, Tokyo, Tokyo Japan
| | - Stanley M. Lemon
- Departments of Medicine and Microbiology & Immunology , The University of North Carolina, Chapel Hill, North Carolina USA
| | - Christopher M. Walker
- Center for Vaccines and Immunity, The Research Institute at Nationwide Children's Hospital, Columbus, Ohio USA
| | - Takaji Wakita
- National Institute of Infectious Diseases, Tokyo, Tokyo Japan
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Ravindran MS, Bagchi P, Cunningham CN, Tsai B. Opportunistic intruders: how viruses orchestrate ER functions to infect cells. Nat Rev Microbiol 2016; 14:407-420. [PMID: 27265768 PMCID: PMC5272919 DOI: 10.1038/nrmicro.2016.60] [Citation(s) in RCA: 80] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Viruses exploit the functions of the endoplasmic reticulum (ER) to promote both early and later stages of their life cycle, including entry, translation, replication, assembly, morphogenesis and egress. This observation reveals a shared principle that underlies virus–host cell relationships. Viral entry often requires disassembly of the incoming virus particle. This is best exemplified in the case of polyomavirus entry, in which ER-associated machineries are hijacked to disassemble the virus and promote entry to the cytosol en route to the nucleus. Many enveloped viruses, such as HIV and influenza virus, co-opt the ER-associated protein biosynthetic machinery to translate their genome and produce structural proteins that are necessary for the formation of virus particles and non-structural proteins that are essential during genome replication. Replication of the viral genome, particularly for positive-sense RNA ((+)RNA) viruses including hepatitis C virus (HCV), dengue virus (DENV) and West Nile virus (WNV), occurs in virus-induced membranous structures that are most often derived from the ER. The formation of these structures requires morphological changes to the ER membrane, involving membrane rearrangements that are induced by viral non-structural proteins that are targeted to the ER. As virus assembly is often coupled to genome replication, the assembly process frequently relies on the ER membrane. This strategy is seen for both RNA and DNA viruses. Morphogenesis of assembled virus particles can also take advantage of the ER. This is best observed in the non-enveloped rotavirus, for which a transient enveloped intermediate is converted to the mature and infectious particle in the lumen of the ER. After maturation in the ER, progeny virus particles egress the host through the ER-dependent secretory pathway, which provides a physical conduit to the extracellular environment. The overall observations that the ER actively promotes all steps of viral infection have therapeutic implications. The development of chemical inhibitors of selective ER-associated components is emerging as a potential avenue of antiviral therapy, provided that these inhibitors have minimal toxicity to the host cell.
Many host structures are vital for viral infection and the endoplasmic reticulum (ER), in particular, is essential. In this Review, Tsai and colleagues highlight examples of subversion of the ER by diverse viruses to promote all stages of their life cycle, from entry to egress. Viruses subvert the functions of their host cells to replicate and form new viral progeny. The endoplasmic reticulum (ER) has been identified as a central organelle that governs the intracellular interplay between viruses and hosts. In this Review, we analyse how viruses from vastly different families converge on this unique intracellular organelle during infection, co-opting some of the endogenous functions of the ER to promote distinct steps of the viral life cycle from entry and replication to assembly and egress. The ER can act as the common denominator during infection for diverse virus families, thereby providing a shared principle that underlies the apparent complexity of relationships between viruses and host cells. As a plethora of information illuminating the molecular and cellular basis of virus–ER interactions has become available, these insights may lead to the development of crucial therapeutic agents.
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Affiliation(s)
- Madhu Sudhan Ravindran
- Department of Cell and Developmental Biology, University of Michigan Medical School, 109 Zina Pitcher Place, Room 3043, Ann Arbor, Michigan 48109, USA
| | - Parikshit Bagchi
- Department of Cell and Developmental Biology, University of Michigan Medical School, 109 Zina Pitcher Place, Room 3043, Ann Arbor, Michigan 48109, USA
| | - Corey Nathaniel Cunningham
- Department of Cell and Developmental Biology, University of Michigan Medical School, 109 Zina Pitcher Place, Room 3043, Ann Arbor, Michigan 48109, USA
| | - Billy Tsai
- Department of Cell and Developmental Biology, University of Michigan Medical School, 109 Zina Pitcher Place, Room 3043, Ann Arbor, Michigan 48109, USA
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Shulla A, Randall G. (+) RNA virus replication compartments: a safe home for (most) viral replication. Curr Opin Microbiol 2016; 32:82-88. [PMID: 27253151 PMCID: PMC4983521 DOI: 10.1016/j.mib.2016.05.003] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Accepted: 05/03/2016] [Indexed: 12/19/2022]
Abstract
(+) RNA virus replication compartments form two structural classes. Both classes of replication compartments use cellular membrane curvature proteins. Both classes of replication compartments manipulate de novo lipid synthesis. Some double membrane vesicles use cellular lipid kinases and transfer proteins. Limited transient replication may occur before replication compartment formation.
This review describes recent advances in our understanding of the mechanisms by which (+) RNA viruses establish their replication niche.
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Affiliation(s)
- Ana Shulla
- Department of Microbiology, The University of Chicago, Chicago, IL 60637, United States
| | - Glenn Randall
- Department of Microbiology, The University of Chicago, Chicago, IL 60637, United States.
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Wang H, Tai AW. Mechanisms of Cellular Membrane Reorganization to Support Hepatitis C Virus Replication. Viruses 2016; 8:v8050142. [PMID: 27213428 PMCID: PMC4885097 DOI: 10.3390/v8050142] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Revised: 04/20/2016] [Accepted: 05/15/2016] [Indexed: 12/13/2022] Open
Abstract
Like all positive-sense RNA viruses, hepatitis C virus (HCV) induces host membrane alterations for its replication termed the membranous web (MW). Assembling replication factors at a membranous structure might facilitate the processes necessary for genome replication and packaging and shield viral components from host innate immune defenses. The biogenesis of the HCV MW is a complex process involving a concerted effort of HCV nonstructural proteins with a growing list of host factors. Although a comprehensive understanding of MW formation is still missing, a number of important viral and host determinants have been identified. This review will summarize the recent studies that have led to our current knowledge of the role of viral and host factors in the biogenesis of the MWs and discuss how HCV uses this specialized membrane structure for its replication.
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Affiliation(s)
- Hongliang Wang
- Division of Gastroenterology, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI 48109, USA.
| | - Andrew W Tai
- Division of Gastroenterology, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI 48109, USA.
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109, USA.
- Medicine Service, Ann Arbor Veterans Administration Health System, Ann Arbor, MI 48105, USA.
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Fernández de Castro I, Tenorio R, Risco C. Virus assembly factories in a lipid world. Curr Opin Virol 2016; 18:20-6. [PMID: 26985879 DOI: 10.1016/j.coviro.2016.02.009] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Revised: 02/11/2016] [Accepted: 02/19/2016] [Indexed: 12/15/2022]
Abstract
Many viruses build specialized structures known as viral factories, a protected environment in which viral genome replication and morphogenesis take place. Recent findings show that viruses manipulate lipid flows to assemble these replication platforms. Viruses are thus able to create new membranes by interfering with lipid metabolism, targeting and transport; they make use of specific lipid transfer proteins (LTP) at membrane contact sites, and frequently recruit endoplasmic reticulum (ER), ER export sites, and mitochondria. Some factories, such as those built by plant and certain animal viruses, are motile membranous structures involved in intracellular or intercellular transport of the replicated viral genome. The identification of lipids and LTP subverted by viruses might lead to better understand and fight viral infections.
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Affiliation(s)
- Isabel Fernández de Castro
- Cell Structure Laboratory, Centro Nacional de Biotecnología, CNB-CSIC, UAM, Campus de Cantoblanco, 28049 Madrid, Spain.
| | - Raquel Tenorio
- Cell Structure Laboratory, Centro Nacional de Biotecnología, CNB-CSIC, UAM, Campus de Cantoblanco, 28049 Madrid, Spain
| | - Cristina Risco
- Cell Structure Laboratory, Centro Nacional de Biotecnología, CNB-CSIC, UAM, Campus de Cantoblanco, 28049 Madrid, Spain.
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Xue J, Liu Y, Yang Y, Wu S, Hu Y, Yang F, Zhou X, Wang J, Chen F, Zheng M, Zhu H, Chen Z. MEAN inhibits hepatitis C virus replication by interfering with a polypyrimidine tract-binding protein. J Cell Mol Med 2016; 20:1255-65. [PMID: 26929148 PMCID: PMC4929307 DOI: 10.1111/jcmm.12798] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2015] [Accepted: 12/22/2015] [Indexed: 01/10/2023] Open
Abstract
MEAN (6‐methoxyethylamino‐numonafide) is a small molecule compound, and here, we report that it effectively inhibits hepatitis C virus (HCV) infection in an HCV cell culture system using a JC1‐Luc chimeric virus, with a 50% effective concentration (EC50) of 2.36 ± 0.29 μM. Drug combination usage analyses demonstrated that MEAN was synergistic with interferon α, ITX5061 and ribavirin. In addition, MEAN effectively inhibits N415D mutant virus and G451R mutant viral infections. Mechanistic studies show that the treatment of HCV‐infected hepatocytes with MEAN inhibits HCV replication but not translation. Furthermore, treatment with MEAN significantly reduces polypyrimidine tract‐binding protein (PTB) levels and blocks the cytoplasmic redistribution of PTB upon infection. In the host cytoplasm, PTB is directly associated with HCV replication, and the inhibition of HCV replication by MEAN can result in the sequestration of PTB in treated nuclei. Taken together, these results indicate that MEAN is a potential therapeutic candidate for HCV infection, and the targeting of the nucleo‐cytoplasmic translocation of the host PTB protein could be a novel strategy to interrupt HCV replication.
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Affiliation(s)
- Jihua Xue
- State Key Lab of Diagnostic and Treatment of Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Disease, 1st Affiliated Hospital of Medical School, Zhejiang University, Hangzhou, China
| | - Yanning Liu
- State Key Lab of Diagnostic and Treatment of Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Disease, 1st Affiliated Hospital of Medical School, Zhejiang University, Hangzhou, China
| | - Ying Yang
- State Key Lab of Diagnostic and Treatment of Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Disease, 1st Affiliated Hospital of Medical School, Zhejiang University, Hangzhou, China
| | - Shanshan Wu
- State Key Lab of Diagnostic and Treatment of Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Disease, 1st Affiliated Hospital of Medical School, Zhejiang University, Hangzhou, China
| | - Ying Hu
- State Key Lab of Diagnostic and Treatment of Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Disease, 1st Affiliated Hospital of Medical School, Zhejiang University, Hangzhou, China
| | - Fan Yang
- State Key Lab of Diagnostic and Treatment of Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Disease, 1st Affiliated Hospital of Medical School, Zhejiang University, Hangzhou, China
| | - Xiaotang Zhou
- State Key Lab of Diagnostic and Treatment of Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Disease, 1st Affiliated Hospital of Medical School, Zhejiang University, Hangzhou, China
| | | | - Feng Chen
- State Key Lab of Diagnostic and Treatment of Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Disease, 1st Affiliated Hospital of Medical School, Zhejiang University, Hangzhou, China
| | - Min Zheng
- State Key Lab of Diagnostic and Treatment of Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Disease, 1st Affiliated Hospital of Medical School, Zhejiang University, Hangzhou, China
| | - Haihong Zhu
- State Key Lab of Diagnostic and Treatment of Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Disease, 1st Affiliated Hospital of Medical School, Zhejiang University, Hangzhou, China
| | - Zhi Chen
- State Key Lab of Diagnostic and Treatment of Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Disease, 1st Affiliated Hospital of Medical School, Zhejiang University, Hangzhou, China
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The counterflow transport of sterols and PI4P. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1861:940-951. [PMID: 26928592 DOI: 10.1016/j.bbalip.2016.02.024] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Revised: 02/23/2016] [Accepted: 02/24/2016] [Indexed: 02/03/2023]
Abstract
Cholesterol levels in intracellular membranes are constantly adjusted to match with specific organelle functions. Cholesterol is kept high in the plasma membrane (PM) because it is essential for its barrier function, while low levels are found in the endoplasmic reticulum (ER) where cholesterol mediates feedback control of its own synthesis by sterol-sensor proteins. The ER→Golgi→PM concentration gradient of cholesterol in mammalian cells, and ergosterol in yeast, appears to be sustained by specific intracellular transport processes, which are mostly mediated by lipid transfer proteins (LTPs). Here we review a recently described function of two LTPs, OSBP and its yeast homolog Osh4p, which consists in creating a sterol gradient between membranes by vectorial transport. OSBP also contributes to the formation of ER/Golgi membrane contact sites, which are important hubs for the transfer of several lipid species. OSBP and Osh4p organize a counterflow transport of lipids whereby sterols are exchanged for the phosphoinositide PI4P, which is used as a fuel to drive sterol transport. This article is part of a Special Issue entitled: The cellular lipid landscape edited by Tim P. Levine and Anant K. Menon.
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Helms JB, Kaloyanova DV, Strating JRP, van Hellemond JJ, van der Schaar HM, Tielens AGM, van Kuppeveld FJM, Brouwers JF. Targeting of the hydrophobic metabolome by pathogens. Traffic 2016; 16:439-60. [PMID: 25754025 PMCID: PMC7169838 DOI: 10.1111/tra.12280] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Revised: 01/09/2015] [Accepted: 01/09/2015] [Indexed: 12/12/2022]
Abstract
The hydrophobic molecules of the metabolome – also named the lipidome – constitute a major part of the entire metabolome. Novel technologies show the existence of a staggering number of individual lipid species, the biological functions of which are, with the exception of only a few lipid species, unknown. Much can be learned from pathogens that have evolved to take advantage of the complexity of the lipidome to escape the immune system of the host organism and to allow their survival and replication. Different types of pathogens target different lipids as shown in interaction maps, allowing visualization of differences between different types of pathogens. Bacterial and viral pathogens target predominantly structural and signaling lipids to alter the cellular phenotype of the host cell. Fungal and parasitic pathogens have complex lipidomes themselves and target predominantly the release of polyunsaturated fatty acids from the host cell lipidome, resulting in the generation of eicosanoids by either the host cell or the pathogen. Thus, whereas viruses and bacteria induce predominantly alterations in lipid metabolites at the host cell level, eukaryotic pathogens focus on interference with lipid metabolites affecting systemic inflammatory reactions that are part of the immune system. A better understanding of the interplay between host–pathogen interactions will not only help elucidate the fundamental role of lipid species in cellular physiology, but will also aid in the generation of novel therapeutic drugs.
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Affiliation(s)
- J Bernd Helms
- Department of Biochemistry and Cell Biology, Faculty of Veterinary Medicine & Institute of Biomembranes, Utrecht University, Yalelaan 2, 3584 CM, Utrecht, The Netherlands
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Yin P, Hong Z, Yang X, Chung RT, Zhang L. A role for retromer in hepatitis C virus replication. Cell Mol Life Sci 2016; 73:869-81. [PMID: 26298293 PMCID: PMC11108358 DOI: 10.1007/s00018-015-2027-7] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Revised: 08/13/2015] [Accepted: 08/18/2015] [Indexed: 12/20/2022]
Abstract
Hepatitis C virus (HCV) has infected over 170 million people worldwide. Phosphatidylinositol 4-phosphate (PI4P) is the organelle-specific phosphoinositide enriched at sites of HCV replication. Whether retromer, a PI4P-related host transport machinery, unloads its cargo at HCV replication sites remains inconclusive. We sought to characterize the role of retromer in HCV replication. Here, we demonstrated the interaction between retromer subunit Vps35 and HCV NS5A protein by immunoprecipitation and GST pulldown. Vps35 colocalized with NS5A and PI4P in both OR6 replicon and JFH1 infected Huh 7.5.1 cells. HCV replication was inhibited upon silencing retromer subunits. CIMPR, a typical retromer cargo, participated in HCV replication. Our data suggest that retromer component Vps35 is recruited by NS5A to viral replication sites where PI4P unloads CIMPR. These findings demonstrate a dependence role of retromer in HCV replication and identify retromer as a potential therapeutic target against HCV.
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Affiliation(s)
- Peiqi Yin
- MOH Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100176, China
| | - Zhi Hong
- MOH Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100176, China
| | - Xiaojie Yang
- MOH Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100176, China
| | - Raymond T Chung
- Gastrointestinal Division, Department of Medicine, Liver Center, Massachusetts General Hospital, Harvard Medical School, Boston, MA, 02114, USA
| | - Leiliang Zhang
- MOH Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100176, China.
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Provazzi PJS, Mukherjee S, Hanson AM, Nogueira ML, Carneiro BM, Frick DN, Rahal P. Analysis of the Enzymatic Activity of an NS3 Helicase Genotype 3a Variant Sequence Obtained from a Relapse Patient. PLoS One 2015; 10:e0144638. [PMID: 26658750 PMCID: PMC4684341 DOI: 10.1371/journal.pone.0144638] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Accepted: 11/20/2015] [Indexed: 12/15/2022] Open
Abstract
The hepatitis C virus (HCV) is a species of diverse genotypes that infect over 170 million people worldwide, causing chronic inflammation, cirrhosis and hepatocellular carcinoma. HCV genotype 3a is common in Brazil, and it is associated with a relatively poor response to current direct-acting antiviral therapies. The HCV NS3 protein cleaves part of the HCV polyprotein, and cellular antiviral proteins. It is therefore the target of several HCV drugs. In addition to its protease activity, NS3 is also an RNA helicase. Previously, HCV present in a relapse patient was found to harbor a mutation known to be lethal to HCV genotype 1b. The point mutation encodes the amino acid substitution W501R in the helicase RNA binding site. To examine how the W501R substitution affects NS3 helicase activity in a genotype 3a background, wild type and W501R genotype 3a NS3 alleles were sub-cloned, expressed in E. coli, and the recombinant proteins were purified and characterized. The impact of the W501R allele on genotype 2a and 3a subgenomic replicons was also analyzed. Assays monitoring helicase-catalyzed DNA and RNA unwinding revealed that the catalytic efficiency of wild type genotype 3a NS3 helicase was more than 600 times greater than the W501R protein. Other assays revealed that the W501R protein bound DNA less than 2 times weaker than wild type, and both proteins hydrolyzed ATP at similar rates. In Huh7.5 cells, both genotype 2a and 3a subgenomic HCV replicons harboring the W501R allele showed a severe defect in replication. Since the W501R allele is carried as a minor variant, its replication would therefore need to be attributed to the trans-complementation by other wild type quasispecies.
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Affiliation(s)
- Paola J. S. Provazzi
- São Paulo State University - UNESP, Department of Biology, São José do Rio Preto/SP, CEP: 15054–000, Brazil
- * E-mail:
| | - Sourav Mukherjee
- University of Wisconsin- Milwaukee, Department of Chemistry & Biochemistry, Milwaukee, WI, 53217, United States of America
| | - Alicia M. Hanson
- University of Wisconsin- Milwaukee, Department of Chemistry & Biochemistry, Milwaukee, WI, 53217, United States of America
| | - Mauricio L. Nogueira
- São José do Rio Preto Medical School, Laboratory of Virology, São José do Rio Preto/SP, CEP: 15090–000, Brazil
| | - Bruno M. Carneiro
- São Paulo State University - UNESP, Department of Biology, São José do Rio Preto/SP, CEP: 15054–000, Brazil
| | - David N. Frick
- University of Wisconsin- Milwaukee, Department of Chemistry & Biochemistry, Milwaukee, WI, 53217, United States of America
| | - Paula Rahal
- São Paulo State University - UNESP, Department of Biology, São José do Rio Preto/SP, CEP: 15054–000, Brazil
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Kentala H, Weber-Boyvat M, Olkkonen VM. OSBP-Related Protein Family: Mediators of Lipid Transport and Signaling at Membrane Contact Sites. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2015; 321:299-340. [PMID: 26811291 DOI: 10.1016/bs.ircmb.2015.09.006] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Oxysterol-binding protein (OSBP) and its related protein homologs, ORPs, constitute a conserved family of lipid-binding/transfer proteins (LTPs) expressed ubiquitously in eukaryotes. The ligand-binding domain of ORPs accommodates cholesterol and oxysterols, but also glycerophospholipids, particularly phosphatidylinositol-4-phosphate (PI4P). ORPs have been implicated as intracellular lipid sensors or transporters. Most ORPs carry targeting determinants for the endoplasmic reticulum (ER) and non-ER organelle membrane. ORPs are located and function at membrane contact sites (MCSs), at which ER is closely apposed with other organelle limiting membranes. Such sites have roles in lipid transport and metabolism, control of Ca(2+) fluxes, and signaling events. ORPs are postulated either to transport lipids over MCSs to maintain the distinct lipid compositions of organelle membranes, or to control the activity of enzymes/protein complexes with functions in signaling and lipid metabolism. ORPs may transfer PI4P and another lipid class bidirectionally. Transport of PI4P followed by its hydrolysis would in this model provide the energy for transfer of the other lipid against its concentration gradient. Control of organelle lipid compositions by OSBP/ORPs is important for the life cycles of several pathogenic viruses. Targeting ORPs with small-molecular antagonists is proposed as a new strategy to combat viral infections. Several ORPs are reported to modulate vesicle transport along the secretory or endocytic pathways. Moreover, antagonists of certain ORPs inhibit cancer cell proliferation. Thus, ORPs are LTPs, which mediate interorganelle lipid transport and coordinate lipid signals with a variety of cellular regimes.
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Affiliation(s)
- Henriikka Kentala
- Minerva Foundation Institute for Medical Research, Biomedicum 2U, Helsinki, Finland
| | - Marion Weber-Boyvat
- Minerva Foundation Institute for Medical Research, Biomedicum 2U, Helsinki, Finland
| | - Vesa M Olkkonen
- Minerva Foundation Institute for Medical Research, Biomedicum 2U, Helsinki, Finland
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Cottarel J, Plissonnier ML, Kullolli M, Pitteri S, Clément S, Millarte V, Si-Ahmed SN, Farhan H, Zoulim F, Parent R. FIG4 is a hepatitis C virus particle-bound protein implicated in virion morphogenesis and infectivity with cholesteryl ester modulation potential. J Gen Virol 2015; 97:69-81. [PMID: 26519381 DOI: 10.1099/jgv.0.000331] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
There is growing evidence that virus particles also contain host cell proteins, which provide viruses with certain properties required for entry and release. A proteomic analysis performed on double-gradient-purified hepatitis C virus (HCV) from two highly viraemic patients identified the phosphatidylinositol 3,5-bisphosphate 5-phosphatase FIG4 (KIAA0274) as part of the viral particles. We validated the association using immunoelectron microscopy, immunoprecipitation and neutralization assays in vitro as well as patient-derived virus particles. RNA interference-mediated reduction of FIG4 expression decreased cholesteryl ester (CE) levels along with intra- and extracellular viral infectivity without affecting HCV RNA levels. Likewise, overexpressing FIG4 increased intracellular CE levels as well as intra- and extracellular viral infectivity without affecting viral RNA levels. Triglyceride levels and lipid droplet (LD) parameters remained unaffected. The 3,5-bisphosphate 5-phosphatase active site of FIG4 was found to strongly condition these results. Whilst FIG4 was found to localize to areas corresponding to viral assembly sites, at the immediate vicinity of LDs in calnexin-positive and HCV core-positive regions, no implication of FIG4 in the secretory pathway of the hepatocytes could be found using either FIG4-null mice, in vitro morphometry or functional assays of the ERGIC/Golgi compartments. This indicates that FIG4-dependent modulation of HCV infectivity is unrelated to alterations in the functionality of the secretory pathway. As a result of the documented implication of CE in the composition and infectivity of HCV particles, these results suggest that FIG4 binds to HCV and modulates particle formation in a CE-related manner.
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Affiliation(s)
- Jessica Cottarel
- Pathogenesis of Hepatitis B and C - DEVweCAN LabEx, INSERM U1052-CNRS 5286, Centre de Recherche en Cancérologie de Lyon, Université de Lyon, 69008 Lyon, France
| | - Marie-Laure Plissonnier
- Pathogenesis of Hepatitis B and C - DEVweCAN LabEx, INSERM U1052-CNRS 5286, Centre de Recherche en Cancérologie de Lyon, Université de Lyon, 69008 Lyon, France
| | - Majlinda Kullolli
- Canary Center for Cancer Early Detection, Department of Radiology, Stanford University School of Medicine, Palo Alto, CA 94304, USA
| | - Sharon Pitteri
- Canary Center for Cancer Early Detection, Department of Radiology, Stanford University School of Medicine, Palo Alto, CA 94304, USA
| | - Sophie Clément
- Department of Clinical Pathology, University of Geneva, Geneva, Switzerland
| | | | | | - Hesso Farhan
- Department of Biology, University of Konstanz, Germany.,Hôpital d'Orléans, 45000 Orléans, France
| | - Fabien Zoulim
- Pathogenesis of Hepatitis B and C - DEVweCAN LabEx, INSERM U1052-CNRS 5286, Centre de Recherche en Cancérologie de Lyon, Université de Lyon, 69008 Lyon, France.,Hospices Civils de Lyon, Service d'Hépatogastroentérologie, 69001 Lyon, France
| | - Romain Parent
- Pathogenesis of Hepatitis B and C - DEVweCAN LabEx, INSERM U1052-CNRS 5286, Centre de Recherche en Cancérologie de Lyon, Université de Lyon, 69008 Lyon, France
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Singaravelu R, Srinivasan P, Pezacki JP. Armand-Frappier Outstanding Student Award--The emerging role of 25-hydroxycholesterol in innate immunity. Can J Microbiol 2015; 61:521-30. [PMID: 26182401 DOI: 10.1139/cjm-2015-0292] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The metabolic interplay between hosts and viruses plays a crucial role in determining the outcome of viral infection. Viruses reorchestrate the host's primary metabolic gene networks, including genes associated with mevalonate and isoprenoid synthesis, to acquire the necessary energy and structural components for their viral life cycles. Recent work has demonstrated that the interferon-mediated antiviral response suppresses the sterol pathway through production of a signalling molecule, 25-hydroxycholesterol (25HC). This oxysterol has been shown to exert multiple effects, both through incorporation into host cellular membranes as well as through transcriptional control. Herein, we summarize our current understanding of the multifunctional roles of 25HC in the mammalian innate antiviral response.
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Affiliation(s)
- Ragunath Singaravelu
- a Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, ON K1N 6N5, Canada.,b Life Sciences Division, National Research Council Canada, Ottawa, ON K1A 0R6, Canada
| | - Prashanth Srinivasan
- a Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, ON K1N 6N5, Canada.,b Life Sciences Division, National Research Council Canada, Ottawa, ON K1A 0R6, Canada
| | - John Paul Pezacki
- a Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, ON K1N 6N5, Canada.,b Life Sciences Division, National Research Council Canada, Ottawa, ON K1A 0R6, Canada.,c Department of Chemistry, University of Ottawa, Ottawa, ON K1N 6N5, Canada
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Harak C, Lohmann V. Ultrastructure of the replication sites of positive-strand RNA viruses. Virology 2015; 479-480:418-33. [PMID: 25746936 PMCID: PMC7111692 DOI: 10.1016/j.virol.2015.02.029] [Citation(s) in RCA: 112] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Revised: 01/06/2015] [Accepted: 02/16/2015] [Indexed: 12/13/2022]
Abstract
Positive strand RNA viruses replicate in the cytoplasm of infected cells and induce intracellular membranous compartments harboring the sites of viral RNA synthesis. These replication factories are supposed to concentrate the components of the replicase and to shield replication intermediates from the host cell innate immune defense. Virus induced membrane alterations are often generated in coordination with host factors and can be grouped into different morphotypes. Recent advances in conventional and electron microscopy have contributed greatly to our understanding of their biogenesis, but still many questions remain how viral proteins capture membranes and subvert host factors for their need. In this review, we will discuss different representatives of positive strand RNA viruses and their ways of hijacking cellular membranes to establish replication complexes. We will further focus on host cell factors that are critically involved in formation of these membranes and how they contribute to viral replication.
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Affiliation(s)
- Christian Harak
- Department of Infectious Diseases, Molecular Virology, University of Heidelberg, Im Neuenheimer Feld 345, D-69120 Heidelberg, Germany
| | - Volker Lohmann
- Department of Infectious Diseases, Molecular Virology, University of Heidelberg, Im Neuenheimer Feld 345, D-69120 Heidelberg, Germany.
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48
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Cho NJ, Lee C, Pang PS, Pham EA, Fram B, Nguyen K, Xiong A, Sklan EH, Elazar M, Koytak ES, Kersten C, Kanazawa KK, Frank CW, Glenn JS. Phosphatidylinositol 4,5-bisphosphate is an HCV NS5A ligand and mediates replication of the viral genome. Gastroenterology 2015; 148:616-25. [PMID: 25479136 PMCID: PMC4339471 DOI: 10.1053/j.gastro.2014.11.043] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/09/2011] [Revised: 11/21/2014] [Accepted: 11/23/2014] [Indexed: 01/27/2023]
Abstract
BACKGROUND & AIMS Phosphoinositides (PIs) bind and regulate localization of proteins via a variety of structural motifs. PI 4,5-bisphosphate (PI[4,5]P2) interacts with and modulates the function of several proteins involved in intracellular vesicular membrane trafficking. We investigated interactions between PI(4,5)P2 and hepatitis C virus (HCV) nonstructural protein 5A (NS5A) and effects on the viral life cycle. METHODS We used a combination of quartz crystal microbalance, circular dichroism, molecular genetics, and immunofluorescence to study specific binding of PI(4,5)P2 by the HCV NS5A protein. We evaluated the effects of PI(4,5)P2 on the function of NS5A by expressing wild-type or mutant forms of Bart79I or FL-J6/JFH-5'C19Rluc2AUbi21 RNA in Huh7 cells. We also studied the effects of strategies designed to inhibit PI(4,5)P2 on HCV replication in these cells. RESULTS The N-terminal amphipathic helix of NS5A bound specifically to PI(4,5)P2, inducing a conformational change that stabilized the interaction between NS5A and TBC1D20, which is required for HCV replication. A pair of positively charged residues within the amphipathic helix (the basic amino acid PI(4,5)P2 pincer domain) was required for PI(4,5)P2 binding and replication of the HCV-RNA genome. A similar motif was found to be conserved across all HCV isolates, as well as amphipathic helices of many pathogens and apolipoproteins. CONCLUSIONS PI(4,5)P2 binds to HCV NS5A to promote replication of the viral RNA genome in hepatocytes. Strategies to disrupt this interaction might be developed to inhibit replication of HCV and other viruses.
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Affiliation(s)
- Nam-Joon Cho
- Division of Gastroenterology and Hepatology, Department of Medicine, Stanford University School of Medicine, Stanford, California; Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California
| | - Choongho Lee
- Division of Gastroenterology and Hepatology, Department of Medicine, Stanford University School of Medicine, Stanford, California
| | - Phillip S Pang
- Division of Gastroenterology and Hepatology, Department of Medicine, Stanford University School of Medicine, Stanford, California; Division of Infectious Diseases, Stanford University School of Medicine, Stanford, California
| | - Edward A Pham
- Division of Gastroenterology and Hepatology, Department of Medicine, Stanford University School of Medicine, Stanford, California; Division of Infectious Diseases, Stanford University School of Medicine, Stanford, California
| | - Benjamin Fram
- Division of Gastroenterology and Hepatology, Department of Medicine, Stanford University School of Medicine, Stanford, California; Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California
| | - Khanh Nguyen
- Division of Gastroenterology and Hepatology, Department of Medicine, Stanford University School of Medicine, Stanford, California; Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California
| | - Anming Xiong
- Division of Gastroenterology and Hepatology, Department of Medicine, Stanford University School of Medicine, Stanford, California; Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California
| | - Ella H Sklan
- Division of Gastroenterology and Hepatology, Department of Medicine, Stanford University School of Medicine, Stanford, California
| | - Menashe Elazar
- Division of Gastroenterology and Hepatology, Department of Medicine, Stanford University School of Medicine, Stanford, California; Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California
| | - Elif S Koytak
- Division of Gastroenterology and Hepatology, Department of Medicine, Stanford University School of Medicine, Stanford, California
| | - Caroline Kersten
- Division of Gastroenterology and Hepatology, Department of Medicine, Stanford University School of Medicine, Stanford, California
| | - Kay K Kanazawa
- Department of Chemical Engineering, Stanford University, Stanford, California
| | - Curtis W Frank
- Department of Chemical Engineering, Stanford University, Stanford, California
| | - Jeffrey S Glenn
- Division of Gastroenterology and Hepatology, Department of Medicine, Stanford University School of Medicine, Stanford, California; Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California; Veterans Administration Medical Center, Palo Alto, California.
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Evaluation of canonical siRNA and Dicer substrate RNA for inhibition of hepatitis C virus genome replication--a comparative study. PLoS One 2015; 10:e0117742. [PMID: 25705875 PMCID: PMC4338191 DOI: 10.1371/journal.pone.0117742] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2014] [Accepted: 01/01/2015] [Indexed: 01/06/2023] Open
Abstract
Hepatitis C virus (HCV) frequently establishes persistent infections in the liver, leading to the development of chronic hepatitis and, potentially, to liver cirrhosis and hepatocellular carcinoma at later stages. The objective of this study was to test the ability of five Dicer substrate siRNAs (DsiRNA) to inhibit HCV replication and to compare these molecules to canonical 21 nt siRNA. DsiRNA molecules were designed to target five distinct regions of the HCV genome - the 5' UTR and the coding regions for NS3, NS4B, NS5A or NS5B. These molecules were transfected into Huh7.5 cells that stably harboured an HCV subgenomic replicon expressing a firefly luciferase/neoR reporter (SGR-Feo-JFH-1) and were also tested on HCVcc-infected cells. All of the DsiRNAs inhibited HCV replication in both the subgenomic system and HCVcc-infected cells. When DsiRNAs were transfected prior to infection with HCVcc, the inhibition levels reached 99.5%. When directly compared, canonical siRNA and DsiRNA exhibited similar potency of virus inhibition. Furthermore, both types of molecules exhibited similar dynamics of inhibition and frequencies of resistant mutants after 21 days of treatment. Thus, DsiRNA molecules are as potent as 21 nt siRNAs for the inhibition of HCV replication and may provide future approaches for HCV therapy if the emergence of resistant mutants can be addressed.
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50
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Hepatitis C virus attenuates mitochondrial lipid β-oxidation by downregulating mitochondrial trifunctional-protein expression. J Virol 2015; 89:4092-101. [PMID: 25673715 PMCID: PMC4442397 DOI: 10.1128/jvi.01653-14] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
UNLABELLED The course of hepatitis C virus (HCV) infection and disease progression involves alterations in lipid metabolism, leading to symptoms such as hypocholesterolemia and steatosis. Steatosis can be induced by multiple mechanisms, including increases in lipid biosynthesis and uptake, impaired lipoprotein secretion, and/or attenuation of lipid β-oxidation. However, little is known about the effects of HCV on lipid β-oxidation. A previous proteomics study revealed that HCV interacted with both the α- and β-subunits of the mitochondrial trifunctional protein (MTP), an enzyme complex which catalyzes the last 3 steps of mitochondrial lipid β-oxidation for cellular energy production. Here we show that in HCV-infected Huh7.5 cells, lipid β-oxidation was significantly attenuated. Consistently with this, MTP protein and mRNA levels were suppressed by HCV infection. A loss-of-function study showed that MTP depletion rendered cells less responsive to alpha interferon (IFN-α) treatment by impairing IFN-stimulated gene expression. These aspects of host-virus interaction explain how HCV alters host energy homeostasis and how it may also contribute to the establishment of persistent infection in the liver. IMPORTANCE HCV infection triggers metabolic alterations, which lead to significant disease outcomes, such as fatty liver (steatosis). This study revealed that HCV impairs mitochondrial lipid β-oxidation, which results in low lipid combustion. On the other hand, the HCV-induced defects in metabolic status played an important role in the control of the type I interferon system. Under the conditions of impaired lipid β-oxidation, host cells were less responsive to the ability of exogenously added IFN-α to suppress HCV replication. This suggests that interference with lipid β-oxidation may assist the virus in the establishment of a long-term, persistent infection. Further understanding of this aspect of virus-host interaction may lead to improvements in the current standard therapy.
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