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Guo S, Xun M, Fan T, Li X, Yao H, Li X, Wu B, Yang H, Ma C, Wang H. Construction of coxsackievirus B5 viruses with luciferase reporters and their applications in vitro and in vivo. Virol Sin 2023; 38:549-558. [PMID: 37244518 PMCID: PMC10436053 DOI: 10.1016/j.virs.2023.05.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 05/11/2023] [Indexed: 05/29/2023] Open
Abstract
Coxsackievirus belongs to the Picornaviridae family and is one of the major pathogens that cause hand, foot and mouth disease (HFMD) in infants and children with potential serious complications and even deaths. The pathogenesis of this virus is not fully elucidated and no vaccine or antiviral drug has been approved. In this study, a full-length infectious cDNA clone of coxsackievirus B5 virus was assembled and the recombinant virus displayed similar growth kinetics and ability to cause cytopathic effects as the parental virus. Luciferase reporter was then incorporated to generate both full-length and subgenomic replicon (SGR) reporter viruses. The full-length reporter virus is suitable for high-throughput antiviral screening, while the SGR is a useful tool to study viral-host interactions. More importantly, the full-length reporter virus has also been shown to infect the suckling mouse model and the reporter gene could be detected using an in vivo imaging system, thus providing a powerful tool to track viruses in vivo. In summary, we have generated coxsackievirus B5 reporter viruses and provided unique tools for studying virus-host interactions in vitro and in vivo as well as for high-throughput screenings (HTS) to identify novel antivirals.
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Affiliation(s)
- Shangrui Guo
- Department of Pathogen Biology and Immunology, Xi'an Jiaotong University Health Science Center, Xi'an, 710061, China
| | - Meng Xun
- Department of Pathogen Biology and Immunology, Xi'an Jiaotong University Health Science Center, Xi'an, 710061, China
| | - Tingting Fan
- Department of Pathogen Biology and Immunology, Xi'an Jiaotong University Health Science Center, Xi'an, 710061, China
| | - Xinyu Li
- Department of Pathogen Biology and Immunology, Xi'an Jiaotong University Health Science Center, Xi'an, 710061, China
| | - Haoyan Yao
- Department of Gynecology and Obstetrics, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, 710061, China
| | - Xiaozhen Li
- Department of Pathogen Biology and Immunology, Xi'an Jiaotong University Health Science Center, Xi'an, 710061, China
| | - Bo Wu
- Department of Pathogen Biology and Immunology, Xi'an Jiaotong University Health Science Center, Xi'an, 710061, China
| | - Hang Yang
- Department of Pathogen Biology and Immunology, Xi'an Jiaotong University Health Science Center, Xi'an, 710061, China
| | - Chaofeng Ma
- Department of Viral Diseases Laboratory, Xi'an Center for Disease Control and Prevention, Xi'an, 710061, China
| | - Hongliang Wang
- Department of Pathogen Biology and Immunology, Xi'an Jiaotong University Health Science Center, Xi'an, 710061, China.
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Bulankina AV, Richter RM, Welsch C. Regulatory Role of Phospholipids in Hepatitis C Virus Replication and Protein Function. Pathogens 2022; 11:102. [PMID: 35056049 PMCID: PMC8779051 DOI: 10.3390/pathogens11010102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Revised: 01/12/2022] [Accepted: 01/13/2022] [Indexed: 11/16/2022] Open
Abstract
Positive-strand RNA viruses such as hepatitis C virus (HCV) hijack key factors of lipid metabolism of infected cells and extensively modify intracellular membranes to support the viral lifecycle. While lipid metabolism plays key roles in viral particle assembly and maturation, viral RNA synthesis is closely linked to the remodeling of intracellular membranes. The formation of viral replication factories requires a number of interactions between virus proteins and host factors including lipids. The structure-function relationship of those proteins is influenced by their lipid environments and lipids that selectively modulate protein function. Here, we review our current understanding on the roles of phospholipids in HCV replication and of lipid-protein interactions in the structure-function relationship of the NS5A protein. NS5A is a key factor in membrane remodeling in HCV-infected cells and is known to recruit phosphatidylinositol 4-kinase III alpha to generate phosphatidylinositol 4-phosphate at the sites of replication. The dynamic interplay between lipids and viral proteins within intracellular membranes is likely key towards understanding basic mechanisms in the pathobiology of virus diseases, the mode of action of specific antiviral agents and related drug resistance mechanisms.
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Affiliation(s)
- Anna V. Bulankina
- Department of Internal Medicine 1, Goethe University Hospital Frankfurt, 60590 Frankfurt, Germany; (A.V.B.); (R.M.R.)
- Research Group “Molecular Evolution & Adaptation”, 60590 Frankfurt, Germany
| | - Rebecca M. Richter
- Department of Internal Medicine 1, Goethe University Hospital Frankfurt, 60590 Frankfurt, Germany; (A.V.B.); (R.M.R.)
- Research Group “Molecular Evolution & Adaptation”, 60590 Frankfurt, Germany
| | - Christoph Welsch
- Department of Internal Medicine 1, Goethe University Hospital Frankfurt, 60590 Frankfurt, Germany; (A.V.B.); (R.M.R.)
- Research Group “Molecular Evolution & Adaptation”, 60590 Frankfurt, Germany
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Chhajer H, Rizvi VA, Roy R. Life cycle process dependencies of positive-sense RNA viruses suggest strategies for inhibiting productive cellular infection. J R Soc Interface 2021; 18:20210401. [PMID: 34753308 PMCID: PMC8580453 DOI: 10.1098/rsif.2021.0401] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Accepted: 10/18/2021] [Indexed: 12/25/2022] Open
Abstract
Life cycle processes of positive-strand (+)RNA viruses are broadly conserved across families, yet they employ different strategies to grow in the cell. Using a generalized dynamical model for intracellular (+)RNA virus growth, we decipher these life cycle determinants and their dependencies for several viruses and parse the effects of viral mutations, drugs and host cell permissivity. We show that poliovirus employs rapid replication and virus assembly, whereas the Japanese encephalitis virus leverages its higher rate of translation and efficient cellular reorganization compared to the hepatitis C virus. Stochastic simulations demonstrate infection extinction if all seeding (inoculating) viral RNA degrade before establishing robust replication critical for infection. The probability of this productive cellular infection, 'cellular infectivity', is affected by virus-host processes and defined by early life cycle events and viral seeding. An increase in cytoplasmic RNA degradation and delay in vesicular compartment formation reduces infectivity, more so when combined. Synergy among these parameters in limiting (+)RNA virus infection as predicted by our model suggests new avenues for inhibiting infections by targeting the early life cycle bottlenecks.
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Affiliation(s)
- Harsh Chhajer
- Centre for Biosystems Science and Engineering, Indian Institute of Science, Bangalore 560012, Karnataka, India
| | - Vaseef A. Rizvi
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560012, Karnataka, India
| | - Rahul Roy
- Centre for Biosystems Science and Engineering, Indian Institute of Science, Bangalore 560012, Karnataka, India
- Department of Chemical Engineering, Indian Institute of Science, Bangalore 560012, Karnataka, India
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High-Order Epistasis and Functional Coupling of Infection Steps Drive Virus Evolution toward Independence from a Host Pathway. Microbiol Spectr 2021; 9:e0080021. [PMID: 34468191 PMCID: PMC8557862 DOI: 10.1128/spectrum.00800-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The phosphatidylinositol-4 kinase IIIβ (PI4KB)/oxysterol-binding protein (OSBP) family I pathway serves as an essential host pathway for the formation of viral replication complex for viral plus-strand RNA synthesis; however, poliovirus (PV) could evolve toward substantial independence from this host pathway with four mutations. Recessive epistasis of the two mutations (3A-R54W and 2B-F17L) is essential for viral RNA replication. Quantitative analysis of effects of the other two mutations (2B-Q20H and 2C-M187V) on each step of infection reveals functional couplings between viral replication, growth, and spread conferred by the 2B-Q20H mutation, while no enhancing effect was conferred by the 2C-M187V mutation. The effects of the 2B-Q20H mutation occur only via another recessive epistasis between the 3A-R54W/2B-F17L mutations. These mutations confer enhanced replication in PI4KB/OSBP-independent infection concomitantly with an increased ratio of viral plus-strand RNA to the minus-strand RNA. This work reveals the essential roles of the functional coupling and high-order, multi-tiered recessive epistasis in viral evolution toward independence from an obligatory host pathway. IMPORTANCE Each virus has a different strategy for its replication, which requires different host factors. Enterovirus, a model RNA virus, requires host factors PI4KB and OSBP, which form an obligatory functional axis to support viral replication. In an experimental evolution system in vitro, virus mutants that do not depend on these host factors could arise only with four mutations. The two mutations (3A-R54W and 2B-F17L) are required for the replication but are not sufficient to support efficient infection. Another mutation (2B-Q20H) is essential for efficient spread of the virus. The order of introduction of the mutations in the viral genome is essential (known as “epistasis”), and functional couplings of infection steps (i.e., viral replication, growth, and spread) have substantial roles to show the effects of the 2B-Q20H mutation. These observations would provide novel insights into an evolutionary pathway of the virus to require host factors for infection.
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Yang H, Zhao X, Xun M, Ma C, Wang H. Reverse Genetic Approaches for the Generation of Full Length and Subgenomic Replicon of EV71 Virus. Front Microbiol 2021; 12:665879. [PMID: 34093481 PMCID: PMC8172962 DOI: 10.3389/fmicb.2021.665879] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Accepted: 04/26/2021] [Indexed: 01/22/2023] Open
Abstract
Enterovirus 71 (EV71) is a neurotropic pathogen that causes hand, foot, and mouth disease (HFMD) and it has been consistently associated with severe neurological, cardiac, and respiratory complications. Yet there is no specific treatment for this virus and we still know little about the viral pathogenesis. In this study, we first generated an infectious cDNA clone of EV71 virus from a patient virus strain and made a full-length virus with a NanoLuc reporter gene through reverse genetic approaches. The reporter gene of this virus is genetically stable when passaging in cells and could be used for antiviral testing. In addition, we also made subgenomic replicons (SGRs) of EV71, which lacks part of the structural genes dispensable for viral replication and showed that SGR can be used for viral replication study. Overall, these reporter viral systems are useful tools for EV71 pathogenesis study and antiviral screening.
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Affiliation(s)
- Hang Yang
- Department of Pathogen Biology and Immunology, Xi'an Jiaotong University Health Science Center, Xi'an, China
| | - Xiaohui Zhao
- Department of Pathogen Biology and Immunology, Xi'an Jiaotong University Health Science Center, Xi'an, China
| | - Meng Xun
- Department of Pathogen Biology and Immunology, Xi'an Jiaotong University Health Science Center, Xi'an, China
| | - Chaofeng Ma
- Department of Viral Diseases Laboratory, Xi'an Center for Disease Control and Prevention, Xi'an, China
| | - Hongliang Wang
- Department of Pathogen Biology and Immunology, Xi'an Jiaotong University Health Science Center, Xi'an, China.,Key Laboratory of Environment and Genes Related to Diseases, Xi'an Jiaotong University, Xi'an, China
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Whole Lotta Lipids-from HCV RNA Replication to the Mature Viral Particle. Int J Mol Sci 2020; 21:ijms21082888. [PMID: 32326151 PMCID: PMC7215355 DOI: 10.3390/ijms21082888] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Revised: 04/15/2020] [Accepted: 04/17/2020] [Indexed: 02/07/2023] Open
Abstract
Replication of the hepatitis C virus (HCV) strongly relies on various lipid metabolic processes in different steps of the viral life cycle. In general, HCV changes the cells' lipidomic profile by differentially regulating key pathways of lipid synthesis, remodeling, and utilization. In this review, we sum up the latest data mainly from the past five years, emphasizing the role of lipids in HCV RNA replication, assembly, and egress. In detail, we highlight changes in the fatty acid content as well as alterations of the membrane lipid composition during replication vesicle formation. We address the role of lipid droplets as a lipid provider during replication and as an essential hub for HCV assembly. Finally, we depict different ideas of HCV maturation and egress including lipoprotein association and potential secretory routes.
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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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Arita M, Bigay J. Poliovirus Evolution toward Independence from the Phosphatidylinositol-4 Kinase III β/Oxysterol-Binding Protein Family I Pathway. ACS Infect Dis 2019; 5:962-973. [PMID: 30919621 DOI: 10.1021/acsinfecdis.9b00038] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Phosphatidylinositol-4 kinase III β (PI4KB) and oxysterol-binding protein (OSBP) family I provide a conserved host pathway required for enterovirus replication. Here, we analyze the role and essentiality of this pathway in enterovirus replication. Phosphatidylinositol 4-phosphate (PI4P) production and cholesterol accumulation in the replication organelle (RO) are severely suppressed in cells infected with a poliovirus (PV) mutant isolated from a PI4KB-knockout cell line (RD[Δ PI4KB]). Major determinants of the mutant for infectivity in RD(Δ PI4KB) cells map to the A5270U(3A-R54W) and U3881C(2B-F17L) mutations. The 3A mutation is required for PI4KB-independent development of RO. The 2B mutation rather sensitizes PV to PI4KB/OSBP inhibitors by itself but confers substantially complete resistance to the inhibitors with the 3A mutation. The 2B mutation also confers hypersensitivity to interferon alpha treatment on PV. These suggest that the PI4KB/OSBP pathway is not necessarily essential for enterovirus replication in vitro. This work supports a two-step resistance model of enterovirus to PI4KB/OSBP inhibitors involving unique recessive epistasis of 3A and 2B and offers insights into a potential evolutionary pathway of enterovirus toward independence from the PI4KB/OSBP pathway.
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Affiliation(s)
- Minetaro Arita
- Department of Virology II, National Institute of Infectious Diseases, 4-7-1 Gakuen, Musashimurayama-shi, Tokyo 208-0011, Japan
| | - Joëlle Bigay
- Université Côte d’Azur, CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, 660 route des lucioles, Valbonne 06560, France
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Vieyres G, Pietschmann T. HCV Pit Stop at the Lipid Droplet: Refuel Lipids and Put on a Lipoprotein Coat before Exit. Cells 2019; 8:cells8030233. [PMID: 30871009 PMCID: PMC6468556 DOI: 10.3390/cells8030233] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 02/28/2019] [Accepted: 03/04/2019] [Indexed: 02/07/2023] Open
Abstract
The replication cycle of the liver-tropic hepatitis C virus (HCV) is tightly connected to the host lipid metabolism, during the virus entry, replication, assembly and egress stages, but also while the virus circulates in the bloodstream. This interplay coins viral particle properties, governs viral cell tropism, and facilitates immune evasion. This review summarizes our knowledge of these interactions focusing on the late steps of the virus replication cycle. It builds on our understanding of the cell biology of lipid droplets and the biosynthesis of liver lipoproteins and attempts to explain how HCV hijacks these organelles and pathways to assemble its lipo-viro-particles. In particular, this review describes (i) the mechanisms of viral protein translocation to and from the lipid droplet surface and the orchestration of an interface between replication and assembly complexes, (ii) the importance of the triglyceride mobilization from the lipid droplets for HCV assembly, (iii) the interplay between HCV and the lipoprotein synthesis pathway including the role played by apolipoproteins in virion assembly, and finally (iv) the consequences of these complex virus–host interactions on the virion composition and its biophysical properties. The wealth of data accumulated in the past years on the role of the lipid metabolism in HCV assembly and its imprint on the virion properties will guide vaccine design efforts and reinforce our understanding of the hepatic lipid metabolism in health and disease.
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Affiliation(s)
- Gabrielle Vieyres
- Institute of Experimental Virology, TWINCORE, Centre for Experimental and Clinical Infection Research, a Joint Venture between the Medical School Hannover (MHH) and the Helmholtz Centre for Infection Research (HZI), 30625 Hannover, Germany.
| | - Thomas Pietschmann
- Institute of Experimental Virology, TWINCORE, Centre for Experimental and Clinical Infection Research, a Joint Venture between the Medical School Hannover (MHH) and the Helmholtz Centre for Infection Research (HZI), 30625 Hannover, Germany.
- German Centre for Infection Research (DZIF), Partner Site Hannover-Braunschweig, 38124 Braunschweig, Germany.
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Shanmugam S, Nichols AK, Saravanabalaji D, Welsch C, Yi M. HCV NS5A dimer interface residues regulate HCV replication by controlling its self-interaction, hyperphosphorylation, subcellular localization and interaction with cyclophilin A. PLoS Pathog 2018; 14:e1007177. [PMID: 30036383 PMCID: PMC6072203 DOI: 10.1371/journal.ppat.1007177] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Revised: 08/02/2018] [Accepted: 06/25/2018] [Indexed: 12/12/2022] Open
Abstract
The HCV NS5A protein plays multiple roles during viral replication, including viral genome replication and virus particle assembly. The crystal structures of the NS5A N-terminal domain indicated the potential existence of the NS5A dimers formed via at least two or more distinct dimeric interfaces. However, it is unknown whether these different forms of NS5A dimers are involved in its numerous functions. To address this question, we mutated the residues lining the two different NS5A dimer interfaces and determined their effects on NS5A self-interaction, NS5A-cyclophilin A (CypA) interaction, HCV RNA replication and infectious virus production. We found that the mutations targeting either of two dimeric interfaces disrupted the NS5A self-interaction in cells. The NS5A dimer-interrupting mutations also inhibited both viral RNA replication and infectious virus production with some genotypic differences. We also determined that reduced NS5A self-interaction was associated with altered NS5A-CypA interaction, NS5A hyperphosphorylation and NS5A subcellular localization, providing the mechanistic bases for the role of NS5A self-interaction in multiple steps of HCV replication. The NS5A oligomers formed via different interfaces are likely its functional form, since the residues at two different dimeric interfaces played similar roles in different aspects of NS5A functions and, consequently, HCV replication. In conclusion, this study provides novel insight into the functional significance of NS5A self-interaction in different steps of the HCV replication, potentially, in the form of oligomers formed via multiple dimeric interfaces. HCV NS5A is a multifunctional protein involved in both viral RNA replication and infectious virus production, and is a target of one of the most potent antivirals available to date. However, the mode of action of NS5A inhibitors is still unclear due to the lack of mechanistic detail regarding NS5A functions during HCV life cycles. In this study, we have provided evidence that surface-exposed NS5A residues involved in two different dimeric interactions in crystal structures are indeed involved in NS5A self-interactions in cells. We also showed that these NS5A residues play critical role in HCV RNA replication and infectious virus production by regulating NS5A hyperphosphorylation, its subcellular localization and its interaction with host protein CypA. Overall, our data support the functional significance of “NS5A oligomers” formed via multiple interfaces in HCV replication. We speculate that the NS5A inhibitors exploited the NS5A oligomer-dependent functions during HCV replication, rather than targeting individual NS5A, which consequently resulted in their high potency.
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Affiliation(s)
- Saravanabalaji Shanmugam
- Department of Microbiology and Immunology, University of Texas Medical Branch at Galveston, Galveston, Texas, United States of America
| | - Alyssa K. Nichols
- Department of Microbiology and Immunology, University of Texas Medical Branch at Galveston, Galveston, Texas, United States of America
| | - Dhanaranjani Saravanabalaji
- Department of Microbiology and Immunology, University of Texas Medical Branch at Galveston, Galveston, Texas, United States of America
| | - Christoph Welsch
- Department of Internal Medicine I, Goethe University, Frankfurt/Main, Germany
| | - MinKyung Yi
- Department of Microbiology and Immunology, University of Texas Medical Branch at Galveston, Galveston, Texas, United States of America
- * E-mail:
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Grünvogel O, Colasanti O, Lee JY, Klöss V, Belouzard S, Reustle A, Esser-Nobis K, Hesebeck-Brinckmann J, Mutz P, Hoffmann K, Mehrabi A, Koschny R, Vondran FWR, Gotthardt D, Schnitzler P, Neumann-Haefelin C, Thimme R, Binder M, Bartenschlager R, Dubuisson J, Dalpke AH, Lohmann V. Secretion of Hepatitis C Virus Replication Intermediates Reduces Activation of Toll-Like Receptor 3 in Hepatocytes. Gastroenterology 2018. [PMID: 29535029 DOI: 10.1053/j.gastro.2018.03.020] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
BACKGROUND & AIMS Hepatitis C virus (HCV) infections most often result in chronic outcomes, although the virus constantly produces replication intermediates, in particular double-stranded RNA (dsRNA), representing potent inducers of innate immunity. We aimed to characterize the fate of HCV dsRNA in hepatocyte cultures to identify mechanisms contributing to viral persistence in presence of an active innate immune response. METHODS We analyzed hepatocyte-based culture models for HCV for induction of innate immunity, secretion of virus positive- or negative-strand RNA, and viral replication using different quantification methods and microscopy techniques. Expression of pattern recognition receptors was reconstituted in hepatoma cells by lentiviral transduction. RESULTS HCV-infected cells secrete substantial amounts of virus positive- and negative-strand RNAs in extracellular vesicles (EVs), toward the apical and basolateral domain of hepatocytes. Secretion of negative-strand RNA was independent from virus production, and viral RNA secreted in EVs contained higher relative amounts of negative-strands, indicating that mostly virus dsRNA is released. A substantial part of viral replication complexes and dsRNA was found in the endosomal compartment and multivesicular bodies, indicating that secretion of HCV replication intermediates is mediated by the exosomal pathway. Block of vesicle release in HCV-positive cells increased intracellular dsRNA levels and increased activation of toll-like receptor 3, inhibiting HCV replication. CONCLUSIONS Using hepatocyte-based culture models for HCV, we found a portion of HCV dsRNA intermediates to be released from infected cells in EVs, which reduces activation of toll-like receptor 3. This represents a novel mechanism how HCV evades host immune responses, potentially contributing to viral persistence.
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Affiliation(s)
- Oliver Grünvogel
- Department of Infectious Diseases, Molecular Virology, University of Heidelberg, Heidelberg, Germany
| | - Ombretta Colasanti
- Department of Infectious Diseases, Molecular Virology, University of Heidelberg, Heidelberg, Germany
| | - Ji-Young Lee
- Department of Infectious Diseases, Molecular Virology, University of Heidelberg, Heidelberg, Germany
| | - Volker Klöss
- Department of Infectious Diseases, Medical Microbiology and Hygiene, University Hospital Heidelberg, Heidelberg, Germany
| | - Sandrine Belouzard
- University Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, U1019 - UMR 8204 - CIIL- Centre d'Infection et d'Immunité de Lille, France
| | - Anna Reustle
- Department of Infectious Diseases, Molecular Virology, University of Heidelberg, Heidelberg, Germany
| | - Katharina Esser-Nobis
- Department of Infectious Diseases, Molecular Virology, University of Heidelberg, Heidelberg, Germany
| | | | - Pascal Mutz
- Department of Infectious Diseases, Molecular Virology, University of Heidelberg, Heidelberg, Germany; Division of Virus-Associated Carcinogenesis, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Katrin Hoffmann
- Department of General-, Visceral- and Transplantation Surgery, University Hospital Heidelberg, Heidelberg, Germany
| | - Arianeb Mehrabi
- Department of General-, Visceral- and Transplantation Surgery, University Hospital Heidelberg, Heidelberg, Germany
| | - Ronald Koschny
- Department of Gastroenterology, Infectious Diseases and Intoxication, University Hospital Heidelberg, Heidelberg, Germany
| | - Florian W R Vondran
- Regenerative Medicine and Experimental Surgery (ReMediES), Department of General, Visceral and Transplant Surgery, Hannover Medical School, Hannover, Germany; German Center for Infection Research (DZIF), partner site Hannover-Braunschweig, Hannover, Germany
| | - Daniel Gotthardt
- Department of Gastroenterology, Infectious Diseases and Intoxication, University Hospital Heidelberg, Heidelberg, Germany
| | - Paul Schnitzler
- Department of Infectious Diseases, Virology, University of Heidelberg, Heidelberg, Germany
| | - Christoph Neumann-Haefelin
- Department of Medicine II, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg
| | - Robert Thimme
- Department of Medicine II, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg
| | - Marco Binder
- Division of Virus-Associated Carcinogenesis, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Ralf Bartenschlager
- Department of Infectious Diseases, Molecular Virology, University of Heidelberg, Heidelberg, Germany; Division of Virus-Associated Carcinogenesis, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Jean Dubuisson
- University Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, U1019 - UMR 8204 - CIIL- Centre d'Infection et d'Immunité de Lille, France
| | - Alexander H Dalpke
- Department of Infectious Diseases, Medical Microbiology and Hygiene, University Hospital Heidelberg, Heidelberg, Germany
| | - Volker Lohmann
- Department of Infectious Diseases, Molecular Virology, University of Heidelberg, Heidelberg, Germany.
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Lotze J, Wolf P, Reinhardt U, Seitz O, Mörl K, Beck-Sickinger AG. Time-Resolved Tracking of Separately Internalized Neuropeptide Y 2 Receptors by Two-Color Pulse-Chase. ACS Chem Biol 2018; 13:618-627. [PMID: 29268018 DOI: 10.1021/acschembio.7b00999] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Internalization and intracellular trafficking of G protein-coupled receptors (GPCR) plays an important role in the signal transduction. These processes are often highly dynamic and take place rapidly. In the past 10 years, it became obvious that internalized GPCRs are also capable of signaling via arrestin or heterotrimeric G proteins within the endosomal compartment. Real-time imaging of receptors in living cells can help to evaluate the temporal and spatial localization. We achieved a two-color pulse-chase labeling approach, which allowed the tracking of the human neuropeptide Y2 receptor (hY2R) in the same cell at different times. The ability to visualize the internalization pathway of two separately labeled and separately stimulated subsets of hY2R in a time-resolved manner revealed a rapid trafficking. Fusion of the two hY2R subsets was already observed 10 min after stimulation in the early endosomal compartment without subsequent separation of the fused receptor populations. The results demonstrate that the cells do not discriminate between receptors that were stimulated and internalized at different time points.
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Affiliation(s)
- Jonathan Lotze
- Institute of Biochemistry, Leipzig University, 04103 Leipzig, Germany
| | - Philipp Wolf
- Institute of Biochemistry, Leipzig University, 04103 Leipzig, Germany
| | - Ulrike Reinhardt
- Institute of Chemistry, Humboldt-University Berlin, 12489 Berlin, Germany
| | - Oliver Seitz
- Institute of Chemistry, Humboldt-University Berlin, 12489 Berlin, Germany
| | - Karin Mörl
- Institute of Biochemistry, Leipzig University, 04103 Leipzig, Germany
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13
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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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14
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Arita M, Dobrikov G, Pürstinger G, Galabov AS. Allosteric Regulation of Phosphatidylinositol 4-Kinase III Beta by an Antipicornavirus Compound MDL-860. ACS Infect Dis 2017; 3:585-594. [PMID: 28605587 DOI: 10.1021/acsinfecdis.7b00053] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
MDL-860 is a broad-spectrum antipicornavirus compound discovered in 1982 and one of the few promising candidates effective in in vivo virus infection. Despite the effectiveness, the target and the mechanism of action of MDL-860 remain unknown. Here, we have characterized antipoliovirus activity of MDL-860 and identified host phosphatidylinositol-4 kinase III beta (PI4KB) as the target. MDL-860 treatment caused covalent modification and irreversible inactivation of PI4KB. A cysteine residue at amino acid 646 of PI4KB, which locates at the bottom of a surface pocket apart from the active site, was identified as the target site of MDL-860. This work reveals the mechanism of action of this class of PI4KB inhibitors and offers insights into novel allosteric regulation of PI4KB activity.
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Affiliation(s)
- Minetaro Arita
- Department
of Virology II, National Institute of Infectious Diseases, 4-7-1 Gakuen, Musashimurayama-shi, Tokyo 208-0011, Japan
| | - Georgi Dobrikov
- Institute
of Organic Chemistry with Centre of Phytochemistry, Bulgarian Academy of Sciences, Academician Georgi Bonchev Street, Bl. 9, 1113 Sofia, Bulgaria
| | - Gerhard Pürstinger
- Institute
of Pharmacy, University of Innsbruck, Innrain 80/82, A-6020 Innsbruck, Austria
| | - Angel S. Galabov
- The
Stephan Angeloff Institute of Microbiology, Bulgarian Academy of Sciences, 26 Academician Georgi Bonchev Street, 1113 Sofia, Bulgaria
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15
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Remenyi R, Roberts GC, Zothner C, Merits A, Harris M. SNAP-tagged Chikungunya Virus Replicons Improve Visualisation of Non-Structural Protein 3 by Fluorescence Microscopy. Sci Rep 2017; 7:5682. [PMID: 28720784 PMCID: PMC5515888 DOI: 10.1038/s41598-017-05820-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Accepted: 06/06/2017] [Indexed: 11/09/2022] Open
Abstract
Chikungunya virus (CHIKV), a mosquito-borne alphavirus, causes febrile disease, muscle and joint pain, which can become chronic in some individuals. The non-structural protein 3 (nsP3) plays essential roles during infection, but a complete understanding of its function is lacking. Here we used a microscopy-based approach to image CHIKV nsP3 inside human cells. The SNAP system consists of a self-labelling enzyme tag, which catalyses the covalent linking of exogenously supplemented synthetic ligands. Genetic insertion of this tag resulted in viable replicons and specific labelling while preserving the effect of nsP3 on stress granule responses and co-localisation with GTPase Activating Protein (SH3 domain) Binding Proteins (G3BPs). With sub-diffraction, three-dimensional, optical imaging, we visualised nsP3-positive structures with variable density and morphology, including high-density rod-like structures, large spherical granules, and small, low-density structures. Next, we confirmed the utility of the SNAP-tag for studying protein turnover by pulse-chase labelling. We also revealed an association of nsP3 with cellular lipid droplets and examined the spatial relationships between nsP3 and the non-structural protein 1 (nsP1). Together, our study provides a sensitive, specific, and versatile system for fundamental research into the individual functions of a viral non-structural protein during infection with a medically important arthropod-borne virus (arbovirus).
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Affiliation(s)
- Roland Remenyi
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, West Yorkshire, LS2 9JT, United Kingdom
| | - Grace C Roberts
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, West Yorkshire, LS2 9JT, United Kingdom
| | - Carsten Zothner
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, West Yorkshire, LS2 9JT, United Kingdom
| | - Andres Merits
- Institute of Technology, University of Tartu, Tartu, Estonia
| | - Mark Harris
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, West Yorkshire, LS2 9JT, United Kingdom.
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16
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Benzine T, Brandt R, Lovell WC, Yamane D, Neddermann P, De Francesco R, Lemon SM, Perelson AS, Ke R, McGivern DR. NS5A inhibitors unmask differences in functional replicase complex half-life between different hepatitis C virus strains. PLoS Pathog 2017; 13:e1006343. [PMID: 28594932 PMCID: PMC5464671 DOI: 10.1371/journal.ppat.1006343] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Accepted: 04/10/2017] [Indexed: 01/06/2023] Open
Abstract
Hepatitis C virus (HCV) RNA is synthesized by the replicase complex (RC), a macromolecular assembly composed of viral non-structural proteins and cellular co-factors. Inhibitors of the HCV NS5A protein block formation of new RCs but do not affect RNA synthesis by pre-formed RCs. Without new RC formation, existing RCs turn over and are eventually lost from the cell. We aimed to use NS5A inhibitors to estimate the half-life of the functional RC of HCV. We compared different cell culture-infectious strains of HCV that may be grouped based on their sensitivity to lipid peroxidation: robustly replicating, lipid peroxidation resistant (LPOR) viruses (e.g. JFH-1 or H77D) and more slowly replicating, lipid peroxidation sensitive (LPOS) viruses (e.g. H77S.3 and N.2). In luciferase assays, LPOS HCV strains declined under NS5A inhibitor therapy with much slower kinetics compared to LPOR HCV strains. This difference in rate of decline was not observed for inhibitors of the NS5B RNA-dependent RNA polymerase suggesting that the difference was not simply a consequence of differences in RNA stability. In further analyses, we compared two isoclonal HCV variants: the LPOS H77S.3 and the LPOR H77D that differ only by 12 amino acids. Differences in rate of decline between H77S.3 and H77D following NS5A inhibitor addition were not due to amino acid sequences in NS5A but rather due to a combination of amino acid differences in the non-structural proteins that make up the HCV RC. Mathematical modeling of intracellular HCV RNA dynamics suggested that differences in RC stability (half-lives of 3.5 and 9.9 hours, for H77D and H77S.3, respectively) are responsible for the different kinetics of antiviral suppression between LPOS and LPOR viruses. In nascent RNA capture assays, the rate of RNA synthesis decline following NS5A inhibitor addition was significantly faster for H77D compared to H77S.3 indicating different half-lives of functional RCs.
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Affiliation(s)
- Tiffany Benzine
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
- Division of Infectious Diseases, Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Ryan Brandt
- Department of Mathematics, North Carolina State University, Raleigh, North Carolina, United States of America
| | - William C. Lovell
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Daisuke Yamane
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Petra Neddermann
- INGM -Istituto Nazionale di Genetica Molecolare "Romeo ed Enrica Invernizzi", Milan, Italy
| | - Raffaele De Francesco
- INGM -Istituto Nazionale di Genetica Molecolare "Romeo ed Enrica Invernizzi", Milan, Italy
| | - Stanley M. Lemon
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
- Division of Infectious Diseases, Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Alan S. Perelson
- Theoretical Biology and Biophysics, Los Alamos National Laboratory, Los Alamos, New Mexico, United States of America
| | - Ruian Ke
- Department of Mathematics, North Carolina State University, Raleigh, North Carolina, United States of America
| | - David R. McGivern
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
- Division of Infectious Diseases, Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
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