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Dai J, Feng Y, Liao Y, Tan L, Sun Y, Song C, Qiu X, Ding C. Virus infection and sphingolipid metabolism. Antiviral Res 2024; 228:105942. [PMID: 38908521 DOI: 10.1016/j.antiviral.2024.105942] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2024] [Revised: 06/14/2024] [Accepted: 06/19/2024] [Indexed: 06/24/2024]
Abstract
Cellular sphingolipids have vital roles in human virus replication and spread as they are exploited by viruses for cell entry, membrane fusion, genome replication, assembly, budding, and propagation. Intracellular sphingolipid biosynthesis triggers conformational changes in viral receptors and facilitates endosomal escape. However, our current understanding of how sphingolipids precisely regulate viral replication is limited, and further research is required to comprehensively understand the relationships between viral replication and endogenous sphingolipid species. Emerging evidence now suggests that targeting and manipulating sphingolipid metabolism enzymes in host cells is a promising strategy to effectively combat viral infections. Additionally, serum sphingolipid species and concentrations could function as potential serum biomarkers to help monitor viral infection status in different patients. In this work, we comprehensively review the literature to clarify how viruses exploit host sphingolipid metabolism to accommodate viral replication and disrupt host innate immune responses. We also provide valuable insights on the development and use of antiviral drugs in this area.
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Affiliation(s)
- Jun Dai
- Experimental Animal Center, Zunyi Medical University, Zunyi, 563099, China
| | - Yiyi Feng
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai 200241, China; Laboratory of Veterinary Microbiology and Animal Infectious Diseases, College of Animal Sciences and Veterinary Medicine, Guangxi University, Nanning, 530004, Guangxi China
| | - Ying Liao
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai 200241, China
| | - Lei Tan
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai 200241, China
| | - Yingjie Sun
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai 200241, China
| | - Cuiping Song
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai 200241, China
| | - Xusheng Qiu
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai 200241, China.
| | - Chan Ding
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai 200241, China; Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, 225009, China.
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2
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Zhang SS, Zhao Z, Zhang WX, Wu R, Li F, Yang H, Zhang Q, Wei TT, Xi J, Zhou Y, Wang T, Du J, Huang N, Ge Q, Lu QB. Lipidome is a valuable tool for the severity prediction of coronavirus disease 2019. Front Immunol 2024; 15:1337208. [PMID: 38799463 PMCID: PMC11116732 DOI: 10.3389/fimmu.2024.1337208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2023] [Accepted: 04/24/2024] [Indexed: 05/29/2024] Open
Abstract
Objective To describe the lipid metabolic profile of different patients with coronavirus disease 2019 (COVID-19) and contribute new evidence on the progression and severity prediction of COVID-19. Methods This case-control study was conducted in Peking University Third Hospital, China. The laboratory-confirmed COVID-19 patients aged ≥18 years old and diagnosed as pneumonia from December 2022 to January 2023 were included. Serum lipids were detected. The discrimination ability was calculated with the area under the curve (AUC). A random forest (RF) model was conducted to determine the significance of different lipids. Results Totally, 44 COVID-19 patients were enrolled with 16 mild and 28 severe patients. The top 5 super classes were triacylglycerols (TAG, 55.9%), phosphatidylethanolamines (PE, 10.9%), phosphatidylcholines (PC, 6.8%), diacylglycerols (DAG, 5.9%) and free fatty acids (FFA, 3.6%) among the 778 detected lipids from the serum of COVID-19 patients. Certain lipids, especially lysophosphatidylcholines (LPCs), turned to have significant correlations with certain immune/cytokine indexes. Reduced level of LPC 20:0 was observed in severe patients particularly in acute stage. The AUC of LPC 20:0 reached 0.940 in discriminating mild and severe patients and 0.807 in discriminating acute and recovery stages in the severe patients. The results of RF models also suggested the significance of LPCs in predicting the severity and progression of COVID-19. Conclusion Lipids probably have the potential to differentiate and forecast the severity, progression, and clinical outcomes of COVID-19 patients, with implications for immune/inflammatory responses. LPC 20:0 might be a potential target in predicting the progression and outcome and the treatment of COVID-19.
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Affiliation(s)
- Shan-Shan Zhang
- Department of Laboratorial Science and Technology and Vaccine Research Center, School of Public Health, Peking University, Beijing, China
- Center for Infectious Disease and Policy Research and Global Health and Infectious Diseases Group, Peking University, Beijing, China
| | - Zhiling Zhao
- Department of Intensive Care Medicine, Peking University Third Hospital, Beijing, China
| | - Wan-Xue Zhang
- Center for Infectious Disease and Policy Research and Global Health and Infectious Diseases Group, Peking University, Beijing, China
- Department of Epidemiology and Biostatistics, School of Public Health, Peking University, Beijing, China
| | - Rui Wu
- Pulmonary and Critical Care Medicine, Peking University Third Hospital, Beijing, China
| | - Fei Li
- Department of General Surgery, Peking University Third Hospital, Beijing, China
| | - Han Yang
- Center for Infectious Disease and Policy Research and Global Health and Infectious Diseases Group, Peking University, Beijing, China
- Department of Epidemiology and Biostatistics, School of Public Health, Peking University, Beijing, China
| | - Qiang Zhang
- Department of Intensive Care Medicine, Peking University Third Hospital, Beijing, China
| | - Ting-Ting Wei
- Department of Laboratorial Science and Technology and Vaccine Research Center, School of Public Health, Peking University, Beijing, China
- Center for Infectious Disease and Policy Research and Global Health and Infectious Diseases Group, Peking University, Beijing, China
| | - Jingjing Xi
- Department of Intensive Care Medicine, Peking University Third Hospital, Beijing, China
| | - Yiguo Zhou
- Center for Infectious Disease and Policy Research and Global Health and Infectious Diseases Group, Peking University, Beijing, China
- Department of Health Policy and Management, School of Public Health, Peking University, Beijing, China
| | - Tiehua Wang
- Department of Intensive Care Medicine, Peking University Third Hospital, Beijing, China
| | - Juan Du
- Department of Laboratorial Science and Technology and Vaccine Research Center, School of Public Health, Peking University, Beijing, China
- Center for Infectious Disease and Policy Research and Global Health and Infectious Diseases Group, Peking University, Beijing, China
| | - Ninghua Huang
- Department of Laboratorial Science and Technology and Vaccine Research Center, School of Public Health, Peking University, Beijing, China
- Center for Infectious Disease and Policy Research and Global Health and Infectious Diseases Group, Peking University, Beijing, China
| | - Qinggang Ge
- Department of Intensive Care Medicine, Peking University Third Hospital, Beijing, China
| | - Qing-Bin Lu
- Department of Laboratorial Science and Technology and Vaccine Research Center, School of Public Health, Peking University, Beijing, China
- Center for Infectious Disease and Policy Research and Global Health and Infectious Diseases Group, Peking University, Beijing, China
- Department of Epidemiology and Biostatistics, School of Public Health, Peking University, Beijing, China
- Department of Health Policy and Management, School of Public Health, Peking University, Beijing, China
- Key Laboratory of Epidemiology of Major Diseases (Peking University), Ministry of Education, Beijing, China
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3
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Röhrig AM, Jakobi K, Dietz J, Thomas D, Herrmann E, Welsch C, Sarrazin C, Pfeilschifter J, Zeuzem S, Grammatikos G. The role of serum sphingolipids as potential biomarkers of non-response to direct acting antiviral therapy in chronic hepatitis C virus infection. J Viral Hepat 2023; 30:138-147. [PMID: 36463431 DOI: 10.1111/jvh.13776] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Revised: 11/07/2022] [Accepted: 11/14/2022] [Indexed: 12/09/2022]
Abstract
Elimination strategies of chronic hepatitis C virus (HCV) infection aim to optimize the high antiviral potency of direct-acting antivirals (DAAs). Sphingolipids (SLs) constitute bioactive lipid compounds with a remarkable second messenger potential. SL levels associate with responsiveness to interferon treatment in HCV-patients, thus prompting the question whether failure to DAAs can be predicted by the serologic sphingolipidomic profile. Liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) was used to retrospectively quantify various sphingolipid metabolites in baseline serum samples of 97 chronic HCV patients with DAA failure compared with an age-matched cohort of 95 HCV-patients with sustained virological response (SVR). Sphingosine, sphinganine, sphingosine-1-phosphate (S1P) and sphinganine-1-phosphate (SA1P) serum concentrations were significantly upregulated at baseline in patients with DAA failure compared to patients with SVR. Similarly, GluC24:1Cer baseline levels were significantly upregulated in patients with DAA failure compared to the patients with SVR. However, GluC18Cer serum levels showed decreased baseline levels for patients with DAA failure compared to patients with SVR. In multivariate analysis sphinganine (OR 0.08494, CI 0.07393-0.9759, p = .021223), SA1P (OR 0.9818, CI 0.9653-0.9987, p = .034801), GluCerC18 (OR 1.0683, CI 1.0297-1.1104, p = .000786) and GluCer24:1 (OR 0.9961, CI 0.994-0.998, p = .000294) constituted independent predictors of treatment response. In conclusion, serum sphingolipid concentrations, in particular sphingosine, sphinganine and their derivatives S1P and SA1P as well as glucosylceramides may identify at baseline the minority of HCV patients with DAA failure. Serum sphingolipids could constitute additional biomarkers for national treatment strategies aiming to eliminate HCV infection.
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Affiliation(s)
- Aissa Miriam Röhrig
- Department of Internal Medicine 1, Goethe University Hospital, Frankfurt am Main, Germany
| | - Katja Jakobi
- Goethe University Hospital, Pharmazentrum Frankfurt/ZAFES, Frankfurt am Main, Germany
| | - Julia Dietz
- Department of Internal Medicine 1, Goethe University Hospital, Frankfurt am Main, Germany
| | - Dominique Thomas
- Goethe University, Institute of Clinical Pharmacology, Frankfurt am Main, Germany
| | - Eva Herrmann
- Department of Medicine, Goethe University, Institute of Biostatistics and Mathematical Modelling, Frankfurt am Main, Germany
| | - Christoph Welsch
- Department of Internal Medicine 1, Goethe University Hospital, Frankfurt am Main, Germany
| | - Christoph Sarrazin
- Department of Internal Medicine 1, Goethe University Hospital, Frankfurt am Main, Germany.,St. Josefs-Hospital, Wiesbaden, Germany
| | - Josef Pfeilschifter
- Goethe University Hospital, Pharmazentrum Frankfurt/ZAFES, Frankfurt am Main, Germany
| | - Stefan Zeuzem
- Department of Internal Medicine 1, Goethe University Hospital, Frankfurt am Main, Germany
| | - Georgios Grammatikos
- Department of Internal Medicine 1, Goethe University Hospital, Frankfurt am Main, Germany.,St' Lukes Hospital, Thessaloniki, Greece
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Hayashi Y, Matsuda K, Tanigawa K, Tanikawa T, Maeda K, Tsuchiya K. Dihydroceramide Δ4-Desaturase 1 Is Not Involved in SARS-CoV-2 Infection. Biol Pharm Bull 2022; 45:1559-1563. [PMID: 36184516 DOI: 10.1248/bpb.b22-00503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Dihydroceramide Δ4-desaturase 1 (DEGS1) enzymatic activity is inhibited with N-(4-hydroxyphenyl)-retinamide (4-HPR). We reported previously that 4-HPR suppresses severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) entry through a DEGS1-independent mechanism. However, it remains unclear whether DEGS1 is involved in other SARS-CoV-2 infection processes, such as virus replication and release. Here we established DEGS1 knockout (KO) in VeroE6TMPRSS2 cells. No significant difference was observed in virus production in the culture supernatant between wild-type (WT) cells and DEGS1-KO cells, although the levels of dihydroceramide (DHCer), a DEGS1 substrate, were significantly higher in DEGS1-KO cells than WT cells. Furthermore, the virus-induced cytopathic effect was also observed in DEGS1-KO cells. Importantly, the EC50 value of 4-HPR in DEGS1-KO cells was almost identical to the value reported previously in WT cells. Our results indicated the lack of involvement of DEGS1 in SARS-CoV-2 infection.
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Affiliation(s)
| | - Kouki Matsuda
- Department of Refractory Viral Infections, National Center for Global Health and Medicine Research Institute
| | | | - Takashi Tanikawa
- Faculty of Pharmacy and Pharmaceutical Sciences, Josai University
| | - Kenji Maeda
- Division of Antiviral Therapy, Joint Research Center for Human Retrovirus Infection, Kagoshima University
| | - Kiyoto Tsuchiya
- AIDS Clinical Center, National Center for Global Health and Medicine
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5
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Modulation of Zika virus replication via glycosphingolipids. Virology 2022; 572:17-27. [DOI: 10.1016/j.virol.2022.03.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 03/30/2022] [Accepted: 03/30/2022] [Indexed: 11/18/2022]
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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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7
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Avota E, Bodem J, Chithelen J, Mandasari P, Beyersdorf N, Schneider-Schaulies J. The Manifold Roles of Sphingolipids in Viral Infections. Front Physiol 2021; 12:715527. [PMID: 34658908 PMCID: PMC8511394 DOI: 10.3389/fphys.2021.715527] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Accepted: 09/06/2021] [Indexed: 12/13/2022] Open
Abstract
Sphingolipids are essential components of eukaryotic cells. In this review, we want to exemplarily illustrate what is known about the interactions of sphingolipids with various viruses at different steps of their replication cycles. This includes structural interactions during entry at the plasma membrane or endosomal membranes, early interactions leading to sphingolipid-mediated signal transduction, interactions with internal membranes and lipids during replication, and interactions during virus assembly and budding. Targeted interventions in sphingolipid metabolism - as far as they can be tolerated by cells and organisms - may open novel possibilities to support antiviral therapies. Human immunodeficiency virus type 1 (HIV-1) infections have intensively been studied, but for other viral infections, such as influenza A virus (IAV), measles virus (MV), hepatitis C virus (HCV), dengue virus, Ebola virus, and severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2), investigations are still in their beginnings. As many inhibitors of sphingolipid metabolism are already in clinical use against other diseases, repurposing studies for applications in some viral infections appear to be a promising approach.
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Affiliation(s)
- Elita Avota
- Institute for Virology and Immunobiology, University of Würzburg, Würzburg, Germany
| | - Jochen Bodem
- Institute for Virology and Immunobiology, University of Würzburg, Würzburg, Germany
| | - Janice Chithelen
- Institute for Virology and Immunobiology, University of Würzburg, Würzburg, Germany
| | - Putri Mandasari
- Institute for Virology and Immunobiology, University of Würzburg, Würzburg, Germany
| | - Niklas Beyersdorf
- Institute for Virology and Immunobiology, University of Würzburg, Würzburg, Germany
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8
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Schneider-Schaulies S, Schumacher F, Wigger D, Schöl M, Waghmare T, Schlegel J, Seibel J, Kleuser B. Sphingolipids: Effectors and Achilles Heals in Viral Infections? Cells 2021; 10:cells10092175. [PMID: 34571822 PMCID: PMC8466362 DOI: 10.3390/cells10092175] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 08/16/2021] [Accepted: 08/20/2021] [Indexed: 12/26/2022] Open
Abstract
As viruses are obligatory intracellular parasites, any step during their life cycle strictly depends on successful interaction with their particular host cells. In particular, their interaction with cellular membranes is of crucial importance for most steps in the viral replication cycle. Such interactions are initiated by uptake of viral particles and subsequent trafficking to intracellular compartments to access their replication compartments which provide a spatially confined environment concentrating viral and cellular components, and subsequently, employ cellular membranes for assembly and exit of viral progeny. The ability of viruses to actively modulate lipid composition such as sphingolipids (SLs) is essential for successful completion of the viral life cycle. In addition to their structural and biophysical properties of cellular membranes, some sphingolipid (SL) species are bioactive and as such, take part in cellular signaling processes involved in regulating viral replication. It is especially due to the progress made in tools to study accumulation and dynamics of SLs, which visualize their compartmentalization and identify interaction partners at a cellular level, as well as the availability of genetic knockout systems, that the role of particular SL species in the viral replication process can be analyzed and, most importantly, be explored as targets for therapeutic intervention.
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Affiliation(s)
- Sibylle Schneider-Schaulies
- Institute for Virology and Immunobiology, University of Wuerzburg, 97078 Würzburg, Germany; (S.S.-S.); (M.S.); (T.W.)
| | - Fabian Schumacher
- Institute of Pharmacy, Pharmacology and Toxicology, Freie Universität Berlin, 14195 Berlin, Germany; (F.S.); (D.W.)
| | - Dominik Wigger
- Institute of Pharmacy, Pharmacology and Toxicology, Freie Universität Berlin, 14195 Berlin, Germany; (F.S.); (D.W.)
| | - Marie Schöl
- Institute for Virology and Immunobiology, University of Wuerzburg, 97078 Würzburg, Germany; (S.S.-S.); (M.S.); (T.W.)
| | - Trushnal Waghmare
- Institute for Virology and Immunobiology, University of Wuerzburg, 97078 Würzburg, Germany; (S.S.-S.); (M.S.); (T.W.)
| | - Jan Schlegel
- Department for Biotechnology and Biophysics, University of Wuerzburg, 97074 Würzburg, Germany;
| | - Jürgen Seibel
- Department for Organic Chemistry, University of Wuerzburg, 97074 Würzburg, Germany;
| | - Burkhard Kleuser
- Institute of Pharmacy, Pharmacology and Toxicology, Freie Universität Berlin, 14195 Berlin, Germany; (F.S.); (D.W.)
- Correspondence: ; Tel.: +49-30-8386-9823
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9
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Hayashi Y, Tsuchiya K, Yamamoto M, Nemoto-Sasaki Y, Tanigawa K, Hama K, Ueda Y, Tanikawa T, Gohda J, Maeda K, Inoue JI, Yamashita A. N-(4-Hydroxyphenyl) Retinamide Suppresses SARS-CoV-2 Spike Protein-Mediated Cell-Cell Fusion by a Dihydroceramide Δ4-Desaturase 1-Independent Mechanism. J Virol 2021; 95:e0080721. [PMID: 34106748 PMCID: PMC8354230 DOI: 10.1128/jvi.00807-21] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Accepted: 05/28/2021] [Indexed: 02/02/2023] Open
Abstract
The membrane fusion between the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and host cells is essential for the initial step of infection; therefore, the host cell membrane components, including sphingolipids, influence the viral infection. We assessed several inhibitors of the enzymes pertaining to sphingolipid metabolism, against SARS-CoV-2 spike protein (S)-mediated cell-cell fusion and viral infection. N-(4-Hydroxyphenyl) retinamide (4-HPR), an inhibitor of dihydroceramide Δ4-desaturase 1 (DES1), suppressed cell-cell fusion and viral infection. The analysis of sphingolipid levels revealed that the inhibition efficiencies of cell-cell fusion and viral infection in 4-HPR-treated cells were consistent with an increased ratio of saturated sphinganine-based lipids to total sphingolipids. We investigated the relationship of DES1 with the inhibition efficiencies of cell-cell fusion. The changes in the sphingolipid profile induced by 4-HPR were mitigated by the supplementation with exogenous cell-permeative ceramide; however, the reduced cell-cell fusion could not be reversed. The efficiency of cell-cell fusion in DES1 knockout (KO) cells was at a level comparable to that in wild-type (WT) cells; however, the ratio of saturated sphinganine-based lipids to the total sphingolipids was higher in DES1 KO cells than in WT cells. 4-HPR reduced cell membrane fluidity without any significant effects on the expression or localization of angiotensin-converting enzyme 2, the SARS-CoV-2 receptor. Therefore, 4-HPR suppresses SARS-CoV-2 S-mediated membrane fusion through a DES1-independent mechanism, and this decrease in membrane fluidity induced by 4-HPR could be the major cause for the inhibition of SARS-CoV-2 infection. IMPORTANCE Sphingolipids could play an important role in SARS-CoV-2 S-mediated membrane fusion with host cells. We studied the cell-cell fusion using SARS-CoV-2 S-expressing cells and sphingolipid-manipulated target cells, with an inhibitor of the sphingolipid metabolism. 4-HPR (also known as fenretinide) is an inhibitor of DES1, and it exhibits antitumor activity and suppresses cell-cell fusion and viral infection. 4-HPR suppresses membrane fusion through a decrease in membrane fluidity, which could possibly be the cause for the inhibition of SARS-CoV-2 infection. There is accumulating clinical data on the safety of 4-HPR. Therefore, it could be a potential candidate drug against COVID-19.
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Affiliation(s)
| | - Kiyoto Tsuchiya
- AIDS Clinical Center, National Center for Global Health and Medicine Hospital, Tokyo, Japan
| | - Mizuki Yamamoto
- Research Center for Asian Infectious Diseases, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan
| | | | | | - Kotaro Hama
- Faculty of Pharma-Science, Teikyo University, Tokyo, Japan
| | - Yusuke Ueda
- Faculty of Pharma-Science, Teikyo University, Tokyo, Japan
| | - Takashi Tanikawa
- Faculty of Pharmacy and Pharmaceutical Sciences, Josai University, Saitama, Japan
| | - Jin Gohda
- Research Center for Asian Infectious Diseases, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan
| | - Kenji Maeda
- Department of Refractory Viral Infections, National Center for Global Health and Medicine Research Institute, Tokyo, Japan
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10
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Wang J, Chen YL, Li YK, Chen DK, He JF, Yao N. Functions of Sphingolipids in Pathogenesis During Host-Pathogen Interactions. Front Microbiol 2021; 12:701041. [PMID: 34408731 PMCID: PMC8366399 DOI: 10.3389/fmicb.2021.701041] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Accepted: 06/21/2021] [Indexed: 12/23/2022] Open
Abstract
Sphingolipids are a class of membrane lipids that serve as vital structural and signaling bioactive molecules in organisms ranging from yeast to animals. Recent studies have emphasized the importance of sphingolipids as signaling molecules in the development and pathogenicity of microbial pathogens including bacteria, fungi, and viruses. In particular, sphingolipids play key roles in regulating the delicate balance between microbes and hosts during microbial pathogenesis. Some pathogens, such as bacteria and viruses, harness host sphingolipids to promote development and infection, whereas sphingolipids from both the host and pathogen are involved in fungus-host interactions. Moreover, a regulatory role for sphingolipids has been described, but their effects on host physiology and metabolism remain to be elucidated. Here, we summarize the current state of knowledge about the roles of sphingolipids in pathogenesis and interactions with host factors, including how sphingolipids modify pathogen and host metabolism with a focus on pathogenesis regulators and relevant metabolic enzymes. In addition, we discuss emerging perspectives on targeting sphingolipids that function in host-microbe interactions as new therapeutic strategies for infectious diseases.
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Affiliation(s)
- Jian Wang
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resource, School of Agriculture, Sun Yat-sen University, Guangzhou, China
| | - Yi-Li Chen
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resource, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Yong-Kang Li
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resource, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Ding-Kang Chen
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resource, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Jia-Fan He
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resource, School of Agriculture, Sun Yat-sen University, Guangzhou, China
| | - Nan Yao
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resource, School of Agriculture, Sun Yat-sen University, Guangzhou, China
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resource, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
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11
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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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12
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Dissanayake TK, Yan B, Ng ACK, Zhao H, Chan G, Yip CCY, Sze KH, To KKW. Differential role of sphingomyelin in influenza virus, rhinovirus and SARS-CoV-2 infection of Calu-3 cells. J Gen Virol 2021; 102. [PMID: 33956593 DOI: 10.1099/jgv.0.001593] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Host cell lipids play a pivotal role in the pathogenesis of respiratory virus infection. However, a direct comparison of the lipidomic profile of influenza virus and rhinovirus infections is lacking. In this study, we first compared the lipid profile of influenza virus and rhinovirus infection in a bronchial epithelial cell line. Most lipid features were downregulated for both influenza virus and rhinovirus, especially for the sphingomyelin features. Pathway analysis showed that sphingolipid metabolism was the most perturbed pathway. Functional study showed that bacterial sphingomyelinase suppressed influenza virus and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) replication, but promoted rhinovirus replication. These findings suggest that sphingomyelin pathway can be a potential target for antiviral therapy, but should be carefully evaluated as it has opposite effects on different respiratory viruses. Furthermore, the differential effect of sphingomyelinase on rhinovirus and influenza virus may explain the interference between rhinovirus and influenza virus infection.
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Affiliation(s)
- Thrimendra Kaushika Dissanayake
- State Key Laboratory for Emerging Infectious Diseases, Carol Yu Centre for Infection, Department of Microbiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong Special Administrative Region, PR China
| | - Bingpeng Yan
- State Key Laboratory for Emerging Infectious Diseases, Carol Yu Centre for Infection, Department of Microbiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong Special Administrative Region, PR China
| | - Anthony Chin-Ki Ng
- State Key Laboratory for Emerging Infectious Diseases, Carol Yu Centre for Infection, Department of Microbiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong Special Administrative Region, PR China
| | - Hanjun Zhao
- State Key Laboratory for Emerging Infectious Diseases, Carol Yu Centre for Infection, Department of Microbiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong Special Administrative Region, PR China
| | - Gabriella Chan
- State Key Laboratory for Emerging Infectious Diseases, Carol Yu Centre for Infection, Department of Microbiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong Special Administrative Region, PR China
| | - Cyril Chik-Yan Yip
- Department of Microbiology, Queen Mary Hospital, Pokfulam, Hong Kong Special Administrative Region, PR China
| | - Kong-Hung Sze
- State Key Laboratory for Emerging Infectious Diseases, Carol Yu Centre for Infection, Department of Microbiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong Special Administrative Region, PR China
| | - Kelvin Kai-Wang To
- State Key Laboratory for Emerging Infectious Diseases, Carol Yu Centre for Infection, Department of Microbiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong Special Administrative Region, PR China.,Department of Microbiology, Queen Mary Hospital, Pokfulam, Hong Kong Special Administrative Region, PR China
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13
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Li HC, Yang CH, Lo SY. Hepatitis C Viral Replication Complex. Viruses 2021; 13:v13030520. [PMID: 33809897 PMCID: PMC8004249 DOI: 10.3390/v13030520] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Revised: 03/18/2021] [Accepted: 03/19/2021] [Indexed: 12/16/2022] Open
Abstract
The life cycle of the hepatitis C virus (HCV) can be divided into several stages, including viral entry, protein translation, RNA replication, viral assembly, and release. HCV genomic RNA replication occurs in the replication organelles (RO) and is tightly linked to ER membrane alterations containing replication complexes (proteins NS3 to NS5B). The amplification of HCV genomic RNA could be regulated by the RO biogenesis, the viral RNA structure (i.e., cis-acting replication elements), and both viral and cellular proteins. Studies on HCV replication have led to the development of direct-acting antivirals (DAAs) targeting the replication complex. This review article summarizes the viral and cellular factors involved in regulating HCV genomic RNA replication and the DAAs that inhibit HCV replication.
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Affiliation(s)
- Hui-Chun Li
- Department of Biochemistry, Tzu Chi University, Hualien 97004, Taiwan;
| | - Chee-Hing Yang
- Department of Laboratory Medicine and Biotechnology, Tzu Chi University, Hualien 97004, Taiwan;
| | - Shih-Yen Lo
- Department of Laboratory Medicine and Biotechnology, Tzu Chi University, Hualien 97004, Taiwan;
- Department of Laboratory Medicine, Buddhist Tzu Chi General Hospital, Hualien 97004, Taiwan
- Correspondence: ; Tel.: +886-3-8565301 (ext. 2322)
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14
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Avota E, Bodem J, Chithelen J, Mandasari P, Beyersdorf N, Schneider-Schaulies J. The Manifold Roles of Sphingolipids in Viral Infections. Front Physiol 2021. [PMID: 34658908 DOI: 10.3389/fphys.2021.71552] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/08/2023] Open
Abstract
Sphingolipids are essential components of eukaryotic cells. In this review, we want to exemplarily illustrate what is known about the interactions of sphingolipids with various viruses at different steps of their replication cycles. This includes structural interactions during entry at the plasma membrane or endosomal membranes, early interactions leading to sphingolipid-mediated signal transduction, interactions with internal membranes and lipids during replication, and interactions during virus assembly and budding. Targeted interventions in sphingolipid metabolism - as far as they can be tolerated by cells and organisms - may open novel possibilities to support antiviral therapies. Human immunodeficiency virus type 1 (HIV-1) infections have intensively been studied, but for other viral infections, such as influenza A virus (IAV), measles virus (MV), hepatitis C virus (HCV), dengue virus, Ebola virus, and severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2), investigations are still in their beginnings. As many inhibitors of sphingolipid metabolism are already in clinical use against other diseases, repurposing studies for applications in some viral infections appear to be a promising approach.
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Affiliation(s)
- Elita Avota
- Institute for Virology and Immunobiology, University of Würzburg, Würzburg, Germany
| | - Jochen Bodem
- Institute for Virology and Immunobiology, University of Würzburg, Würzburg, Germany
| | - Janice Chithelen
- Institute for Virology and Immunobiology, University of Würzburg, Würzburg, Germany
| | - Putri Mandasari
- Institute for Virology and Immunobiology, University of Würzburg, Würzburg, Germany
| | - Niklas Beyersdorf
- Institute for Virology and Immunobiology, University of Würzburg, Würzburg, Germany
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15
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Sphingomyelin Is Essential for the Structure and Function of the Double-Membrane Vesicles in Hepatitis C Virus RNA Replication Factories. J Virol 2020; 94:JVI.01080-20. [PMID: 32938759 DOI: 10.1128/jvi.01080-20] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Accepted: 09/05/2020] [Indexed: 02/07/2023] Open
Abstract
Some plus-stranded RNA viruses generate double-membrane vesicles (DMVs), one type of the membrane replication factories, as replication sites. Little is known about the lipid components involved in the biogenesis of these vesicles. Sphingomyelin (SM) is required for hepatitis C virus (HCV) replication, but the mechanism of SM involvement remains poorly understood. SM biosynthesis starts in the endoplasmic reticulum (ER) and gives rise to ceramide, which is transported from the ER to the Golgi by the action of ceramide transfer protein (CERT), where it can be converted to SM. In this study, inhibition of SM biosynthesis, either by using small-molecule inhibitors or by knockout (KO) of CERT, suppressed HCV replication in a genotype-independent manner. This reduction in HCV replication was rescued by exogenous SM or ectopic expression of the CERT protein, but not by ectopic expression of nonfunctional CERT mutants. Observing low numbers of DMVs in stable replicon cells treated with a SM biosynthesis inhibitor or in CERT-KO cells transfected with either HCV replicon or with constructs that drive HCV protein production in a replication-independent system indicated the significant importance of SM to DMVs. The degradation of SM of the in vitro-isolated DMVs affected their morphology and increased the vulnerability of HCV RNA and proteins to RNase and protease treatment, respectively. Poliovirus, known to induce DMVs, showed decreased replication in CERT-KO cells, while dengue virus, known to induce invaginated vesicles, did not. In conclusion, these findings indicated that SM is an essential constituent of DMVs generated by some plus-stranded RNA viruses.IMPORTANCE Previous reports assumed that sphingomyelin (SM) is essential for HCV replication, but the mechanism was unclear. In this study, we showed for the first time that SM and ceramide transfer protein (CERT), which is in the SM biosynthesis pathway, are essential for the biosynthesis of double-membrane vesicles (DMVs), the sites of viral replication. Low numbers of DMVs were observed in CERT-KO cells transfected with replicon RNA or with constructs that drive HCV protein production in a replication-independent system. HCV replication was rescued by ectopic expression of the CERT protein, but not by CERT mutants, that abolishes the binding of CERT to vesicle-associated membrane protein-associated protein (VAP) or phosphatidylinositol 4-phosphate (PI4P), indicating new roles for VAP and PI4P in HCV replication. The biosynthesis of DMVs has great importance to replication by a variety of plus-stranded RNA viruses. Understanding of this process is expected to facilitate the development of diagnosis and antivirus.
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16
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Audi A, Soudani N, Dbaibo G, Zaraket H. Depletion of Host and Viral Sphingomyelin Impairs Influenza Virus Infection. Front Microbiol 2020; 11:612. [PMID: 32425895 PMCID: PMC7203554 DOI: 10.3389/fmicb.2020.00612] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Accepted: 03/19/2020] [Indexed: 12/19/2022] Open
Abstract
Influenza A virus (IAV) is a major human respiratory pathogen causing annual epidemics as well as periodic pandemics. A complete understanding of the virus pathogenesis and host factors involved in the viral lifecycle is crucial for developing novel therapeutic approaches. Sphingomyelin (SM) is the most abundant membrane sphingolipid. It preferentially associates with cholesterol to form distinct domains named lipid rafts. Sphingomyelinases, including acid sphingomyelinase (ASMase), catalyzes the hydrolysis of membrane SM and consequently transform lipid rafts into ceramide-enriched membrane platforms. In this study, we investigated the effect of SM hydrolysis on IAV propagation. Depleting plasma membrane SM by exogenous bacterial SMase (bSMase) impaired virus infection and reduced virus entry, whereas exogenous SM enhanced infection. Moreover, the depletion of virus envelope SM also reduced virus infectivity and impaired its attachment and internalization. Nonetheless, inhibition of ASMase by desipramine did not affect IAV infection. Similarly, virus replication was not impaired in Niemann-Pick disease type A (NPA) cells, which lack functional ASMase. IAV infection in A549 cells was associated with suppression of ASMase activity starting at 6 h post-infection. Our data reveals that intact cellular and viral envelope SM is required for efficient IAV infection. Therefore, SM metabolism can be a potential target for therapeutic intervention against influenza virus infection.
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Affiliation(s)
- Amani Audi
- Department of Experimental Pathology, Immunology and Microbiology, Faculty of Medicine, American University of Beirut, Beirut, Lebanon.,Center for Infectious Diseases Research, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | - Nadia Soudani
- Department of Experimental Pathology, Immunology and Microbiology, Faculty of Medicine, American University of Beirut, Beirut, Lebanon.,Center for Infectious Diseases Research, Faculty of Medicine, American University of Beirut, Beirut, Lebanon.,Doctoral School of Science and Technology, Research Platform for Environmental Science (PRASE), Faculty of Sciences, Lebanese University, Beirut, Lebanon
| | - Ghassan Dbaibo
- Center for Infectious Diseases Research, Faculty of Medicine, American University of Beirut, Beirut, Lebanon.,Department of Pediatrics and Adolescent Medicine, Faculty of Medicine, American University of Beirut Medical Center, Beirut, Lebanon.,Department of Biochemistry and Molecular Genetics, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | - Hassan Zaraket
- Department of Experimental Pathology, Immunology and Microbiology, Faculty of Medicine, American University of Beirut, Beirut, Lebanon.,Center for Infectious Diseases Research, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
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17
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Tabata K, Neufeldt CJ, Bartenschlager R. Hepatitis C Virus Replication. Cold Spring Harb Perspect Med 2020; 10:cshperspect.a037093. [PMID: 31570388 DOI: 10.1101/cshperspect.a037093] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Replication and amplification of the viral genome is a key process for all viruses. For hepatitis C virus (HCV), a positive-strand RNA virus, amplification of the viral genome requires the synthesis of a negative-sense RNA template, which is in turn used for the production of new genomic RNA. This process is governed by numerous proteins, both host and viral, as well as distinct lipids and specific RNA elements within the positive- and negative-strand RNAs. Moreover, this process requires specific changes to host cell ultrastructure to create microenvironments conducive to viral replication. This review will focus on describing the processes and factors involved in facilitating or regulating HCV genome replication.
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Affiliation(s)
- Keisuke Tabata
- Department of Infectious Diseases, Molecular Virology, Heidelberg University, 69120 Heidelberg, Germany
| | - Christopher J Neufeldt
- Department of Infectious Diseases, Molecular Virology, Heidelberg University, 69120 Heidelberg, Germany
| | - Ralf Bartenschlager
- Department of Infectious Diseases, Molecular Virology, Heidelberg University, 69120 Heidelberg, Germany.,Division of Virus-Associated Carcinogenesis, German Cancer Research Center, 69120 Heidelberg, Germany.,German Center for Infection Research, Heidelberg Partner Site, 69120 Heidelberg, Germany
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18
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Glucosylceramide synthase maintains influenza virus entry and infection. PLoS One 2020; 15:e0228735. [PMID: 32032363 PMCID: PMC7006932 DOI: 10.1371/journal.pone.0228735] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Accepted: 01/22/2020] [Indexed: 12/18/2022] Open
Abstract
Influenza virus is an enveloped virus wrapped in a lipid bilayer derived from the host cell plasma membrane. Infection by influenza virus is dependent on these host cell lipids, which include sphingolipids. Here we examined the role of the sphingolipid, glucosylceramide, in influenza virus infection by knocking out the enzyme responsible for its synthesis, glucosylceramide synthase (UGCG). We observed diminished influenza virus infection in HEK 293 and A549 UGCG knockout cells and demonstrated that this is attributed to impaired viral entry. We also observed that entry mediated by the glycoproteins of other enveloped viruses that enter cells by endocytosis is also impaired in UGCG knockout cells, suggesting a broader role for UGCG in viral entry by endocytosis.
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19
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Glucosylceramidase Maintains Influenza Virus Infection by Regulating Endocytosis. J Virol 2019; 93:JVI.00017-19. [PMID: 30918081 PMCID: PMC6613767 DOI: 10.1128/jvi.00017-19] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Accepted: 03/14/2019] [Indexed: 01/07/2023] Open
Abstract
Influenza virus is the pathogen responsible for the second largest pandemic in human history. A better understanding of how influenza virus enters host cells may lead to the development of more-efficacious therapies against emerging strains of the virus. Here we show that the glycosphingolipid metabolizing enzyme glucosylceramidase is required for optimal influenza virus trafficking to late endosomes and for consequent fusion, entry, and infection. We also provide evidence that promotion of influenza virus entry by glucosylceramidase extends to other endosome-entering viruses and is due to a general requirement for this enzyme, and hence for optimal levels of glucosylceramide, for efficient trafficking of endogenous cargos, such as the epidermal growth factor (EGF) receptor, along the endocytic pathway. This work therefore has implications for the basic process of endocytosis as well as for pathogenic processes, including virus entry and Gaucher disease. Influenza virus is an RNA virus encapsulated in a lipid bilayer derived from the host cell plasma membrane. Previous studies showed that influenza virus infection depends on cellular lipids, including the sphingolipids sphingomyelin and sphingosine. Here we examined the role of a third sphingolipid, glucosylceramide, in influenza virus infection following clustered regularly interspaced short palindromic repeats with Cas9 (CRISPR-Cas9)-mediated knockout (KO) of its metabolizing enzyme glucosylceramidase (GBA). After confirming GBA knockout of HEK 293 and A549 cells by both Western blotting and lipid mass spectrometry, we observed diminished infection in both KO cell lines by a PR8 (H1N1) green fluorescent protein (GFP) reporter virus. We further showed that the reduction in infection correlated with impaired influenza virus trafficking to late endosomes and hence with fusion and entry. To examine whether GBA is required for other enveloped viruses, we compared the results seen with entry mediated by the glycoproteins of Ebola virus, influenza virus, vesicular stomatitis virus (VSV), and measles virus in GBA knockout cells. Entry inhibition was relatively robust for Ebola virus and influenza virus, modest for VSV, and mild for measles virus, suggesting a greater role for viruses that enter cells by fusing with late endosomes. As the virus studies suggested a general role for GBA along the endocytic pathway, we tested that hypothesis and found that trafficking of epidermal growth factor (EGF) to late endosomes and degradation of its receptor were impaired in GBA knockout cells. Collectively, our findings suggest that GBA is critically important for endocytic trafficking of viruses as well as of cellular cargos, including growth factor receptors. Modulation of glucosylceramide levels may therefore represent a novel accompaniment to strategies to antagonize “late-penetrating” viruses, including influenza virus. IMPORTANCE Influenza virus is the pathogen responsible for the second largest pandemic in human history. A better understanding of how influenza virus enters host cells may lead to the development of more-efficacious therapies against emerging strains of the virus. Here we show that the glycosphingolipid metabolizing enzyme glucosylceramidase is required for optimal influenza virus trafficking to late endosomes and for consequent fusion, entry, and infection. We also provide evidence that promotion of influenza virus entry by glucosylceramidase extends to other endosome-entering viruses and is due to a general requirement for this enzyme, and hence for optimal levels of glucosylceramide, for efficient trafficking of endogenous cargos, such as the epidermal growth factor (EGF) receptor, along the endocytic pathway. This work therefore has implications for the basic process of endocytosis as well as for pathogenic processes, including virus entry and Gaucher disease.
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20
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Fernández-Oliva A, Ortega-González P, Risco C. Targeting host lipid flows: Exploring new antiviral and antibiotic strategies. Cell Microbiol 2019; 21:e12996. [PMID: 30585688 PMCID: PMC7162424 DOI: 10.1111/cmi.12996] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 12/04/2018] [Accepted: 12/17/2018] [Indexed: 12/28/2022]
Abstract
Bacteria and viruses pose serious challenges for humans because they evolve continuously. Despite ongoing efforts, antiviral drugs to treat many of the most troubling viruses have not been approved yet. The recent launch of new antimicrobials is generating hope as more and more pathogens around the world become resistant to available drugs. But extra effort is still needed. One of the current strategies for antiviral and antibiotic drug development is the search for host cellular pathways used by many different pathogens. For example, many viruses and bacteria alter lipid synthesis and transport to build their own organelles inside infected cells. The characterization of these interactions will be fundamental to identify new targets for antiviral and antibiotic drug development. This review discusses how viruses and bacteria subvert cell machineries for lipid synthesis and transport and summarises the most promising compounds that interfere with these pathways.
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Affiliation(s)
| | | | - Cristina Risco
- Cell Structure Lab, National Centre for Biotechnology, CNB-CSIC, Madrid, Spain
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21
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Vázquez RF, Daza Millone MA, Pavinatto FJ, Fanani ML, Oliveira ON, Vela ME, Maté SM. Impact of sphingomyelin acyl chain (16:0 vs 24:1) on the interfacial properties of Langmuir monolayers: A PM-IRRAS study. Colloids Surf B Biointerfaces 2019; 173:549-556. [DOI: 10.1016/j.colsurfb.2018.10.018] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2018] [Revised: 09/28/2018] [Accepted: 10/09/2018] [Indexed: 11/17/2022]
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22
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Forni D, Cagliani R, Pontremoli C, Pozzoli U, Vertemara J, De Gioia L, Clerici M, Sironi M. Evolutionary Analysis Provides Insight Into the Origin and Adaptation of HCV. Front Microbiol 2018; 9:854. [PMID: 29765366 PMCID: PMC5938362 DOI: 10.3389/fmicb.2018.00854] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Accepted: 04/13/2018] [Indexed: 12/12/2022] Open
Abstract
Hepatitis C virus (HCV) belongs to the Hepacivirus genus and is genetically heterogeneous, with seven major genotypes further divided into several recognized subtypes. HCV origin was previously dated in a range between ∼200 and 1000 years ago. Hepaciviruses have been identified in several domestic and wild mammals, the largest viral diversity being observed in bats and rodents. The closest relatives of HCV were found in horses/donkeys (equine hepaciviruses, EHV). However, the origin of HCV as a human pathogen is still an unsolved puzzle. Using a selection-informed evolutionary model, we show that the common ancestor of extant HCV genotypes existed at least 3000 years ago (CI: 3192–5221 years ago), with the oldest genotypes being endemic to Asia. EHV originated around 1100 CE (CI: 291–1640 CE). These time estimates exclude that EHV transmission was mainly sustained by widespread veterinary practices and suggest that HCV originated from a single zoonotic event with subsequent diversification in human populations. We also describe a number of biologically important sites in the major HCV genotypes that have been positively selected and indicate that drug resistance-associated variants are significantly enriched at positively selected sites. HCV exploits several cell-surface molecules for cell entry, but only two of these (CD81 and OCLN) determine the species-specificity of infection. Herein evolutionary analyses do not support a long-standing association between primates and hepaciviruses, and signals of positive selection at CD81 were only observed in Chiroptera. No evidence of selection was detected for OCLN in any mammalian order. These results shed light on the origin of HCV and provide a catalog of candidate genetic modulators of HCV phenotypic diversity.
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Affiliation(s)
- Diego Forni
- Bioinformatics Laboratory, Scientific Institute IRCCS E.Medea, Bosisio Parini, Italy
| | - Rachele Cagliani
- Bioinformatics Laboratory, Scientific Institute IRCCS E.Medea, Bosisio Parini, Italy
| | - Chiara Pontremoli
- Bioinformatics Laboratory, Scientific Institute IRCCS E.Medea, Bosisio Parini, Italy
| | - Uberto Pozzoli
- Bioinformatics Laboratory, Scientific Institute IRCCS E.Medea, Bosisio Parini, Italy
| | - Jacopo Vertemara
- Department of Biotechnology and Biosciences, University of Milan-Bicocca, Milan, Italy
| | - Luca De Gioia
- Department of Biotechnology and Biosciences, University of Milan-Bicocca, Milan, Italy
| | - Mario Clerici
- Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy.,Don C. Gnocchi Foundation Onlus, IRCCS, Milan, Italy
| | - Manuela Sironi
- Bioinformatics Laboratory, Scientific Institute IRCCS E.Medea, Bosisio Parini, Italy
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23
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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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24
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Zhang J, Lan Y, Sanyal S. Modulation of Lipid Droplet Metabolism-A Potential Target for Therapeutic Intervention in Flaviviridae Infections. Front Microbiol 2017; 8:2286. [PMID: 29234310 PMCID: PMC5712332 DOI: 10.3389/fmicb.2017.02286] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Accepted: 11/06/2017] [Indexed: 12/21/2022] Open
Abstract
Lipid droplets (LDs) are endoplasmic reticulum (ER)-related dynamic organelles that store and regulate fatty acids and neutral lipids. They play a central role in cellular energy storage, lipid metabolism and cellular homeostasis. It has become evident that viruses have co-evolved in order to exploit host lipid metabolic pathways. This is especially characteristic of the Flaviviridae family, including hepatitis C virus (HCV) and several flaviviruses. Devoid of an appropriate lipid biosynthetic machinery of their own, these single-strand positive-sense RNA viruses can induce dramatic changes in host metabolic pathways to establish a favorable environment for viral multiplication and acquire essential components to facilitate their assembly and traffic. Here we have reviewed the current knowledge on the intracellular life cycle of those from the Flaviviridae family, with particular emphasis on HCV and dengue virus (DENV), and their association with the biosynthesis and metabolism of LDs, with the aim to identify potential antiviral targets for development of novel therapeutic interventions.
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Affiliation(s)
- Jingshu Zhang
- HKU-Pasteur Research Pole, School of Public Health, Li Ka Shing Faculty of Medicine, University of Hong Kong, Hong Kong, China
| | - Yun Lan
- HKU-Pasteur Research Pole, School of Public Health, Li Ka Shing Faculty of Medicine, University of Hong Kong, Hong Kong, China
| | - Sumana Sanyal
- HKU-Pasteur Research Pole, School of Public Health, Li Ka Shing Faculty of Medicine, University of Hong Kong, Hong Kong, China.,School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, University of Hong Kong, Hong Kong, China
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25
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Strating JR, van Kuppeveld FJ. Viral rewiring of cellular lipid metabolism to create membranous replication compartments. Curr Opin Cell Biol 2017; 47:24-33. [PMID: 28242560 PMCID: PMC7127510 DOI: 10.1016/j.ceb.2017.02.005] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2016] [Revised: 02/02/2017] [Accepted: 02/09/2017] [Indexed: 02/08/2023]
Abstract
Positive-strand RNA (+RNA) viruses (e.g. poliovirus, hepatitis C virus, dengue virus, SARS-coronavirus) remodel cellular membranes to form so-called viral replication compartments (VRCs), which are the sites where viral RNA genome replication takes place. To induce VRC formation, these viruses extensively rewire lipid metabolism. Disparate viruses have many commonalities as well as disparities in their interactions with the host lipidome and accumulate specific sets of lipids (sterols, glycerophospholipids, sphingolipids) at their VRCs. Recent years have seen an upsurge in studies investigating the role of lipids in +RNA virus replication, in particular of sterols, and uncovered that membrane contact sites and lipid transfer proteins are hijacked by viruses and play pivotal roles in VRC formation.
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Affiliation(s)
- Jeroen Rpm Strating
- Utrecht University, Faculty of Veterinary Medicine, Department of Infectious Diseases & Immunology, Division of Virology, Utrecht, The Netherlands.
| | - Frank Jm van Kuppeveld
- Utrecht University, Faculty of Veterinary Medicine, Department of Infectious Diseases & Immunology, Division of Virology, Utrecht, The Netherlands.
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26
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Falcón V, Acosta-Rivero N, González S, Dueñas-Carrera S, Martinez-Donato G, Menéndez I, Garateix R, Silva JA, Acosta E, Kourı J. Ultrastructural and biochemical basis for hepatitis C virus morphogenesis. Virus Genes 2017; 53:151-164. [PMID: 28233195 DOI: 10.1007/s11262-017-1426-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Accepted: 01/06/2017] [Indexed: 12/16/2022]
Abstract
Chronic infection with HCV is a leading cause of cirrhosis, hepatocellular carcinoma and liver failure. One of the least understood steps in the HCV life cycle is the morphogenesis of new viral particles. HCV infection alters the lipid metabolism and generates a variety of microenvironments in the cell cytoplasm that protect viral proteins and RNA promoting viral replication and assembly. Lipid droplets (LDs) have been proposed to link viral RNA synthesis and virion assembly by physically associating these viral processes. HCV assembly, envelopment, and maturation have been shown to take place at specialized detergent-resistant membranes in the ER, rich in cholesterol and sphingolipids, supporting the synthesis of luminal LDs-containing ApoE. HCV assembly involves a regulated allocation of viral and host factors to viral assembly sites. Then, virus budding takes place through encapsidation of the HCV genome and viral envelopment in the ER. Interaction of ApoE with envelope proteins supports the viral particle acquisition of lipids and maturation. HCV secretion has been suggested to entail the ion channel activity of viral p7, several components of the classical trafficking and autophagy pathways, ESCRT, and exosome-mediated export of viral RNA. Here, we review the most recent advances in virus morphogenesis and the interplay between viral and host factors required for the formation of HCV virions.
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Affiliation(s)
- Viviana Falcón
- Centro de Ingeniería Genética y Biotecnología, P.O. Box 6162, C.P. 10600, Havana, Cuba.
| | - Nelson Acosta-Rivero
- National Center for Scientific Research, P.O. Box 6414, 10600, Havana, Cuba. .,Centre for Protein Studies, Faculty of Biology, University of Havana, 10400, Havana, Cuba.
| | | | | | | | - Ivon Menéndez
- Centro de Ingeniería Genética y Biotecnología, P.O. Box 6162, C.P. 10600, Havana, Cuba
| | - Rocio Garateix
- Centro de Ingeniería Genética y Biotecnología, P.O. Box 6162, C.P. 10600, Havana, Cuba
| | - José A Silva
- Centro de Ingeniería Genética y Biotecnología, P.O. Box 6162, C.P. 10600, Havana, Cuba
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27
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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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28
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Abstract
Replication of positive-strand RNA viruses occurs in tight association with reorganized host cell membranes. In a concerted fashion, viral and cellular factors generate distinct organelle-like structures, designated viral replication factories. These virus-induced compartments promote highly efficient genome replication, allow spatiotemporal coordination of the different steps of the viral replication cycle, and protect viral RNA from the hostile cytoplasmic environment. The combined use of ultrastructural and functional studies has greatly increased our understanding of the architecture and biogenesis of viral replication factories. Here, we review common concepts and distinct differences in replication organelle morphology and biogenesis within the Flaviviridae family, exemplified by dengue virus and hepatitis C virus. We discuss recent progress made in our understanding of the complex interplay between viral determinants and subverted cellular membrane homeostasis in biogenesis and maintenance of replication factories of this virus family.
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Affiliation(s)
- David Paul
- Department of Infectious Diseases, Molecular Virology, University of Heidelberg, 69120 Heidelberg, Germany; ,
| | - Ralf Bartenschlager
- Department of Infectious Diseases, Molecular Virology, University of Heidelberg, 69120 Heidelberg, Germany; , .,Division of Virus-Associated Carcinogenesis, German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany
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29
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Grammatikos G, Dietz J, Ferreiros N, Koch A, Dultz G, Bon D, Karakasiliotis I, Lutz T, Knecht G, Gute P, Herrmann E, Zeuzem S, Mavromara P, Sarrazin C, Pfeilschifter J. Persistence of HCV in Acutely-Infected Patients Depletes C24-Ceramide and Upregulates Sphingosine and Sphinganine Serum Levels. Int J Mol Sci 2016; 17:E922. [PMID: 27304952 PMCID: PMC4926455 DOI: 10.3390/ijms17060922] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2016] [Revised: 05/27/2016] [Accepted: 05/31/2016] [Indexed: 12/15/2022] Open
Abstract
Hepatitis C virus (HCV) substantially affects lipid metabolism, and remodeling of sphingolipids appears to be essential for HCV persistence in vitro. The aim of the current study is the evaluation of serum sphingolipid variations during acute HCV infection. We enrolled prospectively 60 consecutive patients with acute HCV infection, most of them already infected with human immunodeficiency virus (HIV), and serum was collected at the time of diagnosis and longitudinally over a six-month period until initiation of antiviral therapy or confirmed spontaneous clearance. Quantification of serum sphingolipids was performed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Spontaneous clearance was observed in 11 out of 60 patients (18.3%), a sustained viral response (SVR) in 43 out of 45 patients (95.5%) receiving an antiviral treatment after follow-up, whereas persistence of HCV occurred in six out of 60 patients (10%). C24-ceramide (C24-Cer)-levels increased at follow-up in patients with spontaneous HCV eradication (p < 0.01), as compared to baseline. Sphingosine and sphinganine values were significantly upregulated in patients unable to clear HCV over time compared to patients with spontaneous clearance of HCV infection on follow-up (p = 0.013 and 0.006, respectively). In summary, the persistence of HCV after acute infection induces a downregulation of C24Cer and a simultaneous elevation of serum sphingosine and sphinganine concentrations.
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Affiliation(s)
- Georgios Grammatikos
- Pharmazentrum Frankfurt, Institut für Allgemeine Pharmakologie, Goethe University Hospital, Frankfurt am Main, Theodor-Stern-Kai 7, 60590 Frankfurt am Main, Germany.
- Medizinische Klinik 1, Goethe University Hospital, Frankfurt am Main, Theodor-Stern-Kai 7, 60590 Frankfurt am Main, Germany.
| | - Julia Dietz
- Medizinische Klinik 1, Goethe University Hospital, Frankfurt am Main, Theodor-Stern-Kai 7, 60590 Frankfurt am Main, Germany.
| | - Nerea Ferreiros
- Pharmazentrum Frankfurt, Institut für klinische Pharmakologie, Goethe University Hospital, 60590 Frankfurt am Main, Germany.
| | - Alexander Koch
- Pharmazentrum Frankfurt, Institut für Allgemeine Pharmakologie, Goethe University Hospital, Frankfurt am Main, Theodor-Stern-Kai 7, 60590 Frankfurt am Main, Germany.
| | - Georg Dultz
- Medizinische Klinik 1, Goethe University Hospital, Frankfurt am Main, Theodor-Stern-Kai 7, 60590 Frankfurt am Main, Germany.
| | - Dimitra Bon
- Institute of Biostatistics and Mathematical Modelling, Department of Medicine, Goethe University, 60590 Frankfurt am Main, Germany.
| | | | - Thomas Lutz
- Infektiologikum, 60590 Frankfurt am Main, Germany.
| | - Gaby Knecht
- Infektiologikum, 60590 Frankfurt am Main, Germany.
| | - Peter Gute
- Infektiologikum, 60590 Frankfurt am Main, Germany.
| | - Eva Herrmann
- Pharmazentrum Frankfurt, Institut für klinische Pharmakologie, Goethe University Hospital, 60590 Frankfurt am Main, Germany.
| | - Stefan Zeuzem
- Medizinische Klinik 1, Goethe University Hospital, Frankfurt am Main, Theodor-Stern-Kai 7, 60590 Frankfurt am Main, Germany.
| | - Penelope Mavromara
- Molecular Virology, Hellenic Pasteur Institute, 11521 Athens, Greece.
- Molecular Biology and Genetics, Democritus University of Thrace, 68100 Alexandroupolis, Greece.
| | - Christoph Sarrazin
- Medizinische Klinik 1, Goethe University Hospital, Frankfurt am Main, Theodor-Stern-Kai 7, 60590 Frankfurt am Main, Germany.
| | - Josef Pfeilschifter
- Pharmazentrum Frankfurt, Institut für Allgemeine Pharmakologie, Goethe University Hospital, Frankfurt am Main, Theodor-Stern-Kai 7, 60590 Frankfurt am Main, Germany.
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30
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Martín-Acebes MA, Gabandé-Rodríguez E, García-Cabrero AM, Sánchez MP, Ledesma MD, Sobrino F, Saiz JC. Host sphingomyelin increases West Nile virus infection in vivo. J Lipid Res 2016; 57:422-32. [PMID: 26764042 DOI: 10.1194/jlr.m064212] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Indexed: 12/16/2022] Open
Abstract
Flaviviruses, such as the dengue virus and the West Nile virus (WNV), are arthropod-borne viruses that represent a global health problem. The flavivirus lifecycle is intimately connected to cellular lipids. Among the lipids co-opted by flaviviruses, we have focused on SM, an important component of cellular membranes particularly enriched in the nervous system. After infection with the neurotropic WNV, mice deficient in acid sphingomyelinase (ASM), which accumulate high levels of SM in their tissues, displayed exacerbated infection. In addition, WNV multiplication was enhanced in cells from human patients with Niemann-Pick type A, a disease caused by a deficiency of ASM activity resulting in SM accumulation. Furthermore, the addition of SM to cultured cells also increased WNV infection, whereas treatment with pharmacological inhibitors of SM synthesis reduced WNV infection. Confocal microscopy analyses confirmed the association of SM with viral replication sites within infected cells. Our results unveil that SM metabolism regulates flavivirus infection in vivo and propose SM as a suitable target for antiviral design against WNV.
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Affiliation(s)
- Miguel A Martín-Acebes
- Departments of Virology and Microbiology Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Madrid 28049, Spain Department of Biotechnology, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Madrid 28040, Spain
| | | | - Ana M García-Cabrero
- Laboratory of Neurology, Instituto de Investigación Sanitaria Fundación Jiménez Díaz, Madrid 28040, Spain
| | - Marina P Sánchez
- Laboratory of Neurology, Instituto de Investigación Sanitaria Fundación Jiménez Díaz, Madrid 28040, Spain
| | - María Dolores Ledesma
- Molecular Neurobiology, Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Madrid 28049, Spain
| | - Francisco Sobrino
- Departments of Virology and Microbiology Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Madrid 28049, Spain
| | - Juan-Carlos Saiz
- Department of Biotechnology, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Madrid 28040, Spain
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31
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Hepatitis C Virus NS4B Can Suppress STING Accumulation To Evade Innate Immune Responses. J Virol 2015; 90:254-65. [PMID: 26468527 DOI: 10.1128/jvi.01720-15] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Accepted: 10/05/2015] [Indexed: 02/07/2023] Open
Abstract
UNLABELLED The cyclic dinucleotide 2',3'-cGAMP can bind the adaptor protein STING (stimulator of interferon [IFN] genes) to activate the production of type I IFNs and proinflammatory cytokines. We found that cGAMP added to the culture medium could suppress the replication of the hepatitis C virus (HCV) genotype 1b strain Con1 subgenomic replicon in human hepatoma cells. Knockdown of STING expression diminished the inhibitory effect on replicon replication, while overexpression of STING enhanced the inhibitory effects of cGAMP. The addition of cGAMP into 1b/Con1 replicon cells significantly increased the expression of type I IFNs and antiviral interferon-stimulated genes. Unexpectedly, replication of the genotype 2a JFH1 replicon and infectious JFH1 virus was less sensitive to the inhibitory effect of cGAMP than was that of 1b/Con1 replicon. Using chimeric replicons, 2a NS4B was identified to confer resistance to cGAMP. Transient expression of 2a NS4B resulted in a pronounced inhibitory effect on STING-mediated beta IFN (IFN-β) reporter activation compared to that of 1b NS4B. 2a NS4B was found to suppress STING accumulation in a dose-dependent manner. The predicted transmembrane domain of 2a NS4B was required to inhibit STING accumulation. These results demonstrate a novel genotype-specific inhibition of the STING-mediated host antiviral immune response. IMPORTANCE The cyclic dinucleotide cGAMP was found to potently inhibit the replication of HCV genotype 1b Con1 replicon but was less effective for the 2a/JFH1 replicon and infectious JFH1 virus. The predicted transmembrane domain in 2a NS4B was shown to be responsible for the decreased sensitivity to cGAMP. The N terminus of NS4B has been reported to suppress STING-mediated signaling by disrupting the interaction of STING and TBK1 and/or MAVS. We show that 2a/JFH1 NS4B has an additional mechanism to evade STING signaling through suppressing STING accumulation.
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32
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Cooperation between the Hepatitis C Virus p7 and NS5B Proteins Enhances Virion Infectivity. J Virol 2015; 89:11523-33. [PMID: 26355084 DOI: 10.1128/jvi.01185-15] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Accepted: 08/31/2015] [Indexed: 02/07/2023] Open
Abstract
UNLABELLED The molecular mechanisms that govern hepatitis C virus (HCV) assembly, release, and infectivity are still not yet fully understood. In the present study, we sequenced a genotype 2A strain of HCV (JFH-1) that had been cell culture adapted in Huh-7.5 cells to produce nearly 100-fold-higher viral titers than the parental strain. Sequence analysis identified nine mutations in the genome, present within both the structural and nonstructural genes. The infectious clone of this virus containing all nine culture-adapted mutations had 10-fold-higher levels of RNA replication and RNA release into the supernatant but had nearly 1,000-fold-higher viral titers, resulting in an increased specific infectivity compared to wild-type JFH-1. Two mutations, identified in the p7 polypeptide and NS5B RNA-dependent RNA polymerase, were sufficient to increase the specific infectivity of JFH-1. We found that the culture-adapted mutation in p7 promoted an increase in the size of cellular lipid droplets following transfection of viral RNA. In addition, we found that the culture-adaptive mutations in p7 and NS5B acted synergistically to enhance the specific viral infectivity of JFH-1 by decreasing the level of sphingomyelin in the virion. Overall, these results reveal a genetic interaction between p7 and NS5B that contributes to virion specific infectivity. Furthermore, our results demonstrate a novel role for the RNA-dependent RNA polymerase NS5B in HCV assembly. IMPORTANCE Hepatitis C virus assembly and release depend on viral interactions with host lipid metabolic pathways. Here, we demonstrate that the viral p7 and NS5B proteins cooperate to promote virion infectivity by decreasing sphingomyelin content in the virion. Our data uncover a new role for the viral RNA-dependent RNA polymerase NS5B and p7 proteins in contributing to virion morphogenesis. Overall, these findings are significant because they reveal a genetic interaction between p7 and NS5B, as well as an interaction with sphingomyelin that regulates virion infectivity. Our data provide new strategies for targeting host lipid-virus interactions as potential targets for therapies against HCV infection.
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33
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Hyodo K, Taniguchi T, Manabe Y, Kaido M, Mise K, Sugawara T, Taniguchi H, Okuno T. Phosphatidic acid produced by phospholipase D promotes RNA replication of a plant RNA virus. PLoS Pathog 2015; 11:e1004909. [PMID: 26020241 PMCID: PMC4447390 DOI: 10.1371/journal.ppat.1004909] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Accepted: 04/23/2015] [Indexed: 12/25/2022] Open
Abstract
Eukaryotic positive-strand RNA [(+)RNA] viruses are intracellular obligate parasites replicate using the membrane-bound replicase complexes that contain multiple viral and host components. To replicate, (+)RNA viruses exploit host resources and modify host metabolism and membrane organization. Phospholipase D (PLD) is a phosphatidylcholine- and phosphatidylethanolamine-hydrolyzing enzyme that catalyzes the production of phosphatidic acid (PA), a lipid second messenger that modulates diverse intracellular signaling in various organisms. PA is normally present in small amounts (less than 1% of total phospholipids), but rapidly and transiently accumulates in lipid bilayers in response to different environmental cues such as biotic and abiotic stresses in plants. However, the precise functions of PLD and PA remain unknown. Here, we report the roles of PLD and PA in genomic RNA replication of a plant (+)RNA virus, Red clover necrotic mosaic virus (RCNMV). We found that RCNMV RNA replication complexes formed in Nicotiana benthamiana contained PLDα and PLDβ. Gene-silencing and pharmacological inhibition approaches showed that PLDs and PLDs-derived PA are required for viral RNA replication. Consistent with this, exogenous application of PA enhanced viral RNA replication in plant cells and plant-derived cell-free extracts. We also found that a viral auxiliary replication protein bound to PA in vitro, and that the amount of PA increased in RCNMV-infected plant leaves. Together, our findings suggest that RCNMV hijacks host PA-producing enzymes to replicate.
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Affiliation(s)
- Kiwamu Hyodo
- Laboratory of Plant Pathology, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Takako Taniguchi
- Institute for Enzyme Research, University of Tokushima, Tokushima, Japan
| | - Yuki Manabe
- Laboratory of Marine Bioproducts Technology, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Masanori Kaido
- Laboratory of Plant Pathology, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Kazuyuki Mise
- Laboratory of Plant Pathology, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Tatsuya Sugawara
- Laboratory of Marine Bioproducts Technology, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Hisaaki Taniguchi
- Institute for Enzyme Research, University of Tokushima, Tokushima, Japan
| | - Tetsuro Okuno
- Laboratory of Plant Pathology, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
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34
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Wen Y, Lin X, Fan B, Ranjith-Kumar CT, Kao CC. The juxtamembrane sequence of the Hepatitis C virus polymerase can affect RNA synthesis and inhibition by allosteric polymerase inhibitors. Virus Genes 2015; 51:1-11. [PMID: 25895103 DOI: 10.1007/s11262-015-1199-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Accepted: 04/09/2015] [Indexed: 12/21/2022]
Abstract
The Hepatitis C virus (HCV) RNA-dependent RNA polymerase (RdRp), nonstructural protein 5B (NS5B), is anchored in the membrane through a C-terminal helix. A sequence of ca. 12 residues that connects the catalytically competent portion of the RdRp and the C-terminal helix, the juxtamembrane sequence (JMS), has a poorly defined role in RdRp function in a large part since it is translated from a cis-acting RNA element (CRE) that is essential for HCV replication. Using a HCV replicon that transposed a second copy of CRE to the 3' UTR of the HCV replicon, we demonstrate that amino acid substitutions in the JMS were detrimental for HCV replicon replication. Substitutions in the JMS also resulted in a defect in de novo-initiated RNAs synthesis in vitro and in a cell-based reporter assay. A nonnucleoside inhibitor of the NS5B that binds to the catalytic pocket was less potent in inhibiting NS5B in the presence of JMS mutations. The JMS mutants exhibit reduced stability in thermodenaturation assays, suggesting that the JMS helps confer a more stable conformation to NS5B that could impact RNA synthesis.
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Affiliation(s)
- Y Wen
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN, 47405, USA
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35
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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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36
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Yamaji T, Hanada K. Sphingolipid metabolism and interorganellar transport: localization of sphingolipid enzymes and lipid transfer proteins. Traffic 2014; 16:101-22. [PMID: 25382749 DOI: 10.1111/tra.12239] [Citation(s) in RCA: 289] [Impact Index Per Article: 28.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Revised: 10/29/2014] [Accepted: 11/06/2014] [Indexed: 11/28/2022]
Abstract
In recent decades, many sphingolipid enzymes, sphingolipid-metabolism regulators and sphingolipid transfer proteins have been isolated and characterized. This review will provide an overview of the intracellular localization and topology of sphingolipid enzymes in mammalian cells to highlight the locations where respective sphingolipid species are produced. Interestingly, three sphingolipids that reside or are synthesized in cytosolic leaflets of membranes (ceramide, glucosylceramide and ceramide-1-phosphate) all have cytosolic lipid transfer proteins (LTPs). These LTPs consist of ceramide transfer protein (CERT), four-phosphate adaptor protein 2 (FAPP2) and ceramide-1-phosphate transfer protein (CPTP), respectively. These LTPs execute functions that affect both the location and metabolism of the lipids they bind. Molecular details describing the mechanisms of regulation of LTPs continue to emerge and reveal a number of critical processes, including competing phosphorylation and dephosphorylation reactions and binding interactions with regulatory proteins and lipids that influence the transport, organelle distribution and metabolism of sphingolipids.
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Affiliation(s)
- Toshiyuki Yamaji
- Department of Biochemistry and Cell Biology, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo, 162-8640, Japan
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37
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Targeting cellular squalene synthase, an enzyme essential for cholesterol biosynthesis, is a potential antiviral strategy against hepatitis C virus. J Virol 2014; 89:2220-32. [PMID: 25473062 DOI: 10.1128/jvi.03385-14] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
UNLABELLED Hepatitis C virus (HCV) exploits host membrane cholesterol and its metabolism for progeny virus production. Here, we examined the impact of targeting cellular squalene synthase (SQS), the first committed enzyme for cholesterol biosynthesis, on HCV production. By using the HCV JFH-1 strain and human hepatoma Huh-7.5.1-derived cells, we found that the SQS inhibitors YM-53601 and zaragozic acid A decreased viral RNA, protein, and progeny production in HCV-infected cells without affecting cell viability. Similarly, small interfering RNA (siRNA)-mediated knockdown of SQS led to significantly reduced HCV production, confirming the enzyme as an antiviral target. A metabolic labeling study demonstrated that YM-53601 suppressed the biosynthesis of cholesterol and cholesteryl esters at antiviral concentrations. Unlike YM-53601, the cholesterol esterification inhibitor Sandoz 58-035 did not exhibit an antiviral effect, suggesting that biosynthesis of cholesterol is more important than that of cholesteryl esters for HCV production. YM-53601 inhibited transient replication of a JFH-1 subgenomic replicon and entry of JFH-1 pseudoparticles, suggesting that at least suppression of viral RNA replication and entry contributes to the antiviral effect of the drug. Collectively, our findings highlight the importance of the cholesterol biosynthetic pathway in HCV production and implicate SQS as a potential target for antiviral strategies against HCV. IMPORTANCE Hepatitis C virus (HCV) is known to be closely associated with host cholesterol and its metabolism throughout the viral life cycle. However, the impact of targeting cholesterol biosynthetic enzymes on HCV production is not fully understood. We found that squalene synthase, the first committed enzyme for cholesterol biosynthesis, is important for HCV production, and we propose this enzyme as a potential anti-HCV target. We provide evidence that synthesis of free cholesterol is more important than that of esterified cholesterol for HCV production, highlighting a marked free cholesterol dependency of HCV production. Our findings also offer a new insight into a role of the intracellular cholesterol pool that is coupled to its biosynthesis in the HCV life cycle.
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38
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Eyre NS, Helbig KJ, Beard MR. Current and future targets of antiviral therapy in the hepatitis C virus life cycle. Future Virol 2014. [DOI: 10.2217/fvl.14.83] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
ABSTRACT Advances in our understanding of the hepatitis C virus (HCV) life cycle have enabled the development of numerous clinically advanced direct-acting antivirals. Indeed, the recent approval of first-generation direct-acting antivirals that target the viral NS3–4A protease and NS5B RNA-dependent RNA polymerase brings closer the possibility of universally efficacious and well-tolerated antiviral therapies for this insidious infection. However, the complexities of comorbidities, unforeseen side effects or drug–drug interactions, viral diversity, the high mutation rate of HCV RNA replication and the elegant and constantly evolving mechanisms employed by HCV to evade host and therapeutically implemented antiviral strategies remain as significant obstacles to this goal. Here, we review advances in our understanding of the HCV life cycle and associated opportunities for antiviral therapy.
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Affiliation(s)
- Nicholas S Eyre
- School of Molecular & Biomedical Science, The University of Adelaide & Centre for Cancer Biology, SA Pathology, Adelaide, South Australia, Australia
| | - Karla J Helbig
- School of Molecular & Biomedical Science, The University of Adelaide & Centre for Cancer Biology, SA Pathology, Adelaide, South Australia, Australia
| | - Michael R Beard
- School of Molecular & Biomedical Science, The University of Adelaide & Centre for Cancer Biology, SA Pathology, Adelaide, South Australia, Australia
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Konan KV, Sanchez-Felipe L. Lipids and RNA virus replication. Curr Opin Virol 2014; 9:45-52. [PMID: 25262061 DOI: 10.1016/j.coviro.2014.09.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Revised: 09/08/2014] [Accepted: 09/08/2014] [Indexed: 12/24/2022]
Abstract
Most viruses rely heavily on their host machinery to successfully replicate their genome and produce new virus particles. Recently, the interaction of positive-strand RNA viruses with the lipid biosynthetic and transport machinery has been the subject of intense investigation. In this review, we will discuss the contribution of various host lipids and related proteins in RNA virus replication and maturation.
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Affiliation(s)
- Kouacou V Konan
- Center for Immunology and Microbial Disease, Albany Medical College, Albany, NY 12208-3479, United States.
| | - Lorena Sanchez-Felipe
- Center for Immunology and Microbial Disease, Albany Medical College, Albany, NY 12208-3479, United States
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Modulation of hepatitis C virus genome replication by glycosphingolipids and four-phosphate adaptor protein 2. J Virol 2014; 88:12276-95. [PMID: 25122779 DOI: 10.1128/jvi.00970-14] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
UNLABELLED Hepatitis C virus (HCV) assembles its replication complex on cytosolic membrane vesicles often clustered in a membranous web (MW). During infection, HCV NS5A protein activates PI4KIIIα enzyme, causing massive production and redistribution of phosphatidylinositol 4-phosphate (PI4P) lipid to the replication complex. However, the role of PI4P in the HCV life cycle is not well understood. We postulated that PI4P recruits host effectors to modulate HCV genome replication or virus particle production. To test this hypothesis, we generated cell lines for doxycycline-inducible expression of short hairpin RNAs (shRNAs) targeting the PI4P effector, four-phosphate adaptor protein 2 (FAPP2). FAPP2 depletion attenuated HCV infectivity and impeded HCV RNA synthesis. Indeed, FAPP2 has two functional lipid-binding domains specific for PI4P and glycosphingolipids. While expression of the PI4P-binding mutant protein was expected to inhibit HCV replication, a marked drop in replication efficiency was observed unexpectedly with the glycosphingolipid-binding mutant protein. These data suggest that both domains are crucial for the role of FAPP2 in HCV genome replication. We also found that HCV significantly increases the level of some glycosphingolipids, whereas adding these lipids to FAPP2-depleted cells partially rescued replication, further arguing for the importance of glycosphingolipids in HCV RNA synthesis. Interestingly, FAPP2 is redistributed to the replication complex (RC) characterized by HCV NS5A, NS4B, or double-stranded RNA (dsRNA) foci. Additionally, FAPP2 depletion disrupts the RC and alters the colocalization of HCV replicase proteins. Altogether, our study implies that HCV coopts FAPP2 for virus genome replication via PI4P binding and glycosphingolipid transport to the HCV RC. IMPORTANCE Like most viruses with a positive-sense RNA genome, HCV replicates its RNA on remodeled host membranes composed of lipids hijacked from various internal membrane compartments. During infection, HCV induces massive production and retargeting of the PI4P lipid to its replication complex. However, the role of PI4P in HCV replication is not well understood. In this study, we have shown that FAPP2, a PI4P effector and glycosphingolipid-binding protein, is recruited to the HCV replication complex and is required for HCV genome replication and replication complex formation. More importantly, this study demonstrates, for the first time, the crucial role of glycosphingolipids in the HCV life cycle and suggests a link between PI4P and glycosphingolipids in HCV genome replication.
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Yamane D, McGivern DR, Wauthier E, Yi M, Madden VJ, Welsch C, Antes I, Wen Y, Chugh PE, McGee CE, Widman DG, Misumi I, Bandyopadhyay S, Kim S, Shimakami T, Oikawa T, Whitmire JK, Heise MT, Dittmer DP, Kao CC, Pitson SM, Merrill AH, Reid LM, Lemon SM. Regulation of the hepatitis C virus RNA replicase by endogenous lipid peroxidation. Nat Med 2014; 20:927-35. [PMID: 25064127 PMCID: PMC4126843 DOI: 10.1038/nm.3610] [Citation(s) in RCA: 114] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Accepted: 05/23/2014] [Indexed: 02/07/2023]
Abstract
Although oxidative tissue injury often accompanies viral infection, there is little understanding of how it influences virus replication. We show that multiple hepatitis C virus (HCV) genotypes are exquisitely sensitive to oxidative membrane damage, a property distinguishing them from other pathogenic RNA viruses. Lipid peroxidation, regulated in part through sphingosine kinase 2, severely restricts HCV replication in Huh-7 cells and primary human hepatoblasts. Endogenous oxidative membrane damage lowers the 50% effective concentration of direct-acting antivirals, suggesting critical regulation of the conformation of the NS3/4A protease and NS5B polymerase, membrane-bound HCV replicase components. Resistance to lipid peroxidation maps genetically to trans-membrane and membrane-proximal residues within these proteins, and is essential for robust replication in cell culture, as exemplified by the atypical JFH1 strain. Thus, the typical, wild-type HCV replicase is uniquely regulated by lipid peroxidation, providing a novel mechanism for attenuating replication in stressed tissue and possibly facilitating long-term viral persistence.
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Affiliation(s)
- Daisuke Yamane
- 1] Department of Medicine, Division of Infectious Diseases, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA. [2] Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - David R McGivern
- 1] Department of Medicine, Division of Infectious Diseases, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA. [2] Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Eliane Wauthier
- 1] Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA. [2] Department of Cell Biology and Physiology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - MinKyung Yi
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, USA
| | - Victoria J Madden
- Department of Pathology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Christoph Welsch
- Department of Internal Medicine I, J.W. Goethe University Hospital, Frankfurt, Germany
| | - Iris Antes
- Center for Integrated Protein Science Munich (CIPSM), Department of Life Sciences, Technical University Munich, Freising, Germany
| | - Yahong Wen
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, Indiana, USA
| | - Pauline E Chugh
- 1] Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA. [2] Department of Microbiology and Immunology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Charles E McGee
- Department of Genetics, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Douglas G Widman
- Department of Epidemiology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Ichiro Misumi
- Department of Genetics, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Sibali Bandyopadhyay
- 1] School of Biology, Georgia Institute of Technology, Atlanta, Georgia, USA. [2] Parker H. Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Seungtaek Kim
- 1] Department of Medicine, Division of Infectious Diseases, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA. [2] Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA. [3] Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, Korea
| | - Tetsuro Shimakami
- 1] Department of Medicine, Division of Infectious Diseases, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA. [2] Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Tsunekazu Oikawa
- 1] Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA. [2] Department of Cell Biology and Physiology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Jason K Whitmire
- 1] Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA. [2] Department of Microbiology and Immunology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA. [3] Department of Genetics, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Mark T Heise
- 1] Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA. [2] Department of Genetics, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Dirk P Dittmer
- 1] Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA. [2] Department of Microbiology and Immunology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - C Cheng Kao
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, Indiana, USA
| | - Stuart M Pitson
- Centre for Cancer Biology, SA Pathology, Adelaide, South Australia, Australia
| | - Alfred H Merrill
- 1] School of Biology, Georgia Institute of Technology, Atlanta, Georgia, USA. [2] Parker H. Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Lola M Reid
- 1] Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA. [2] Department of Cell Biology and Physiology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Stanley M Lemon
- 1] Department of Medicine, Division of Infectious Diseases, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA. [2] Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA. [3] Department of Microbiology and Immunology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
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Qiu Y, Miao M, Wang Z, Liu Y, Yang J, Xia H, Li XF, Qin CF, Hu Y, Zhou X. The RNA binding of protein A from Wuhan nodavirus is mediated by mitochondrial membrane lipids. Virology 2014; 462-463:1-13. [PMID: 25092456 PMCID: PMC7112130 DOI: 10.1016/j.virol.2014.05.022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Revised: 04/06/2014] [Accepted: 05/21/2014] [Indexed: 01/19/2023]
Abstract
RNA replication of positive-strand (+)RNA viruses requires the lipids present in intracellular membranes, the sites of which viral replicases associate with. However, the direct effects of membrane lipids on viral replicases are still poorly understood. Wuhan nodavirus (WhNV) protein A, which associates with mitochondrial membranes, is the sole replicase required for RNA replication. Here, we report that WhNV protein A binds to RNA1 in a cooperative manner. Moreover, mitochondrial membrane lipids (MMLs) stimulated the RNA binding activity and cooperativity of protein A, and such stimulations exhibited strong selectivity for distinct phospholipids. Interestingly, MMLs stimulated the RNA-binding cooperativity only at higher protein A concentrations. Further investigation showed that MMLs stimulate the RNA binding of protein A by promoting its self-interaction. Finally, manipulating MML metabolism affected the protein A-induced RNA1 recruitment in cells. Together, our findings reveal the direct effects of membrane lipids on the RNA binding activity of a nodaviral replicase. WhNV protein A directly binds to RNA1 in a cooperative manner. Mitochondrial membrane lipids (MMLs) stimulate the binding activity of protein A. The RNA binding of protein A is selectively stimulated by specific phospholipids. MMLs enhance the RNA binding of protein A by stimulating its self-interaction. Manipulating phospholipid metabolism regulates protein A-induced RNA1 recruitment.
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Affiliation(s)
- Yang Qiu
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, Hubei 430072, China; State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
| | - Meng Miao
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, Hubei 430072, China
| | - Zhaowei Wang
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, Hubei 430072, China
| | - Yongxiang Liu
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, Hubei 430072, China
| | - Jie Yang
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, Hubei 430072, China
| | - Hongjie Xia
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, Hubei 430072, China
| | - Xiao-Feng Li
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
| | - Cheng-Feng Qin
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
| | - Yuanyang Hu
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, Hubei 430072, China
| | - Xi Zhou
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, Hubei 430072, China.
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43
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Wen Y, Cheng Kao C. The hepatitis C virus core protein can modulate RNA-dependent RNA synthesis by the 2a polymerase. Virus Res 2014; 189:165-76. [PMID: 24874198 DOI: 10.1016/j.virusres.2014.05.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2014] [Revised: 05/01/2014] [Accepted: 05/07/2014] [Indexed: 01/06/2023]
Abstract
RNA replication enzymes are multi-subunit protein complexes whose activity can be modulated by other viral and cellular factors. For genotype 1b Hepatitis C virus (HCV), the RNA-dependent RNA polymerase (RdRp) subunit of the replicase, NS5B, has been reported to interact with the HCV Core protein to decrease RNA synthesis (Kang et al., 2009). Here we used a cell-based assay for RNA synthesis to examine the Core-NS5B interaction of genotype 2a HCV. Unlike the 1b NS5B, the activity of the 2a NS5B was stimulated by the Core protein. Using the bimolecular fluorescence complementation assay, the 2a Core co-localized with 2a NS5B when they were transiently expressed in cells. The two proteins can form a co-immunoprecipitable complex. Deletion analysis showed that the N-terminal 75 residues of 2a Core were required to contact 2a NS5B to modulate its activity. The C-terminal transmembrane helix of 2a NS5B also contributes to the interaction with the 2a Core. To determine the basis for the differential effects of the Core-RdRp interaction, we found that the 2a RdRp activity was enhanced by both the 1b Core and 2a Core. However, the 1b NS5B activity was slightly inhibited by either Core protein. The replication of the 2a JFH-1 replicon was increased by co-expressed 2a Core while the genotype 1b Con1 replicon was not significantly affected by the corresponding Core. Mutations in 2a NS5B that affected the closed RdRp structure were found to be less responsive to 2a Core. Finally, we determined that RNA synthesis by the RdRps from genotypes 2a, 3a and 4a HCV were increased by the Core proteins from HCV of genotypes 1-4. These results reveal another difference between RNA syntheses by the different genotype RdRps and add additional examples of a viral structural protein regulating viral RNA synthesis.
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Affiliation(s)
- Y Wen
- Department of Molecular & Cellular Biochemistry, Indiana University, Bloomington, IN 47405, USA
| | - C Cheng Kao
- Department of Molecular & Cellular Biochemistry, Indiana University, Bloomington, IN 47405, USA.
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WANG HONGLIANG, PERRY JEFFREYW, LAURING ADAMS, NEDDERMANN PETRA, DE FRANCESCO RAFFAELE, TAI ANDREWW. Oxysterol-binding protein is a phosphatidylinositol 4-kinase effector required for HCV replication membrane integrity and cholesterol trafficking. Gastroenterology 2014; 146:1373-85.e1-11. [PMID: 24512803 PMCID: PMC3992183 DOI: 10.1053/j.gastro.2014.02.002] [Citation(s) in RCA: 123] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2013] [Revised: 01/15/2014] [Accepted: 02/03/2014] [Indexed: 01/12/2023]
Abstract
BACKGROUND & AIMS Positive-sense RNA viruses remodel intracellular membranes to generate specialized membrane compartments for viral replication. Several RNA viruses, including poliovirus and hepatitis C virus (HCV), require phosphatidylinositol (PI) 4-kinases for their replication. However, it is not known how PI 4-kinases and their product, PI(4)P, facilitate host membrane reorganization and viral replication. In addition, although the HCV replication compartment, known as the membranous web, is believed to be cholesterol enriched, the mechanisms by which this occurs have not been elucidated. We aimed to identify and characterize a PI 4-kinase effector in HCV replication. METHODS We used a combination of microscopic and biochemical methods to study HCV replication, web morphology, the distribution of intracellular protein and PI(4)P, along with cholesterol trafficking in HCV-infected cells. PI 4-kinase and oxysterol-binding protein (OSBP) were inhibited using RNA interference or small molecules in cells expressing a full-length genotype 1b replicon or infected with the JFH-1 strain of HCV. RESULTS OSBP was required for HCV replication and membranous web integrity. OSBP was recruited to membranous webs in a PI 4-kinase-dependent manner, and both these factors were found to regulate cholesterol trafficking to the web. We also found OSBP to be required for poliovirus infection but dispensable for dengue virus. CONCLUSIONS OSBP is a PI 4-kinase effector in HCV infection, and contributes to the integrity and cholesterol enrichment of the membranous web. OSBP might also be a PI 4-kinase effector in poliovirus infection and could be involved in replication of other viruses that require PI 4-kinases.
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Affiliation(s)
- HONGLIANG WANG
- Division of Gastroenterology, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI
| | - JEFFREY W. PERRY
- Division of Gastroenterology, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI
| | - ADAM S. LAURING
- Division of Infectious Diseases, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI,Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI
| | - PETRA NEDDERMANN
- Virology Program, Istituto Nazionale di Genetica Molecolare (INGM), Milano, Italy
| | | | - ANDREW W. TAI
- Division of Gastroenterology, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI,Division of Gastroenterology, Department of Internal Medicine, Ann Arbor Veterans Administration Health System, Ann Arbor, MI
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45
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Grammatikos G, Mühle C, Ferreiros N, Schroeter S, Bogdanou D, Schwalm S, Hintereder G, Kornhuber J, Zeuzem S, Sarrazin C, Pfeilschifter J. Serum acid sphingomyelinase is upregulated in chronic hepatitis C infection and non alcoholic fatty liver disease. Biochim Biophys Acta Mol Cell Biol Lipids 2014; 1841:1012-20. [PMID: 24769340 DOI: 10.1016/j.bbalip.2014.04.007] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Revised: 04/08/2014] [Accepted: 04/17/2014] [Indexed: 02/07/2023]
Abstract
UNLABELLED Sphingolipids constitute bioactive molecules with functional implications in homeostasis and pathogenesis of various diseases. However, the role of sphingolipids as possible disease biomarkers in chronic liver disease remains largely unexplored. In the present study we used mass spectrometry and spectrofluorometry methods in order to quantify various sphingolipid metabolites and also assess the activity of an important corresponding regulating enzyme in the serum of 72 healthy volunteers as compared to 69 patients with non-alcoholic fatty liver disease and 69 patients with chronic hepatitis C virus infection. Our results reveal a significant upregulation of acid sphingomyelinase in the serum of patients with chronic liver disease as compared to healthy individuals (p<0.001). Especially in chronic hepatitis C infection acid sphingomyelinase activity correlated significantly with markers of hepatic injury (r=0.312, p=0.009) and showed a high discriminative power. Accumulation of various (dihydro-) ceramide species was identified in the serum of patients with non-alcoholic fatty liver disease (p<0.001) and correlated significantly to cholesterol (r=0.448, p<0.001) but showed a significant accumulation in patients with normal cholesterol values as well (p<0.001). Sphingosine, a further bioactive metabolite, was also upregulated in chronic liver disease (p<0.001). However, no significant correlation to markers of hepatic injury was identified. CONCLUSION Chronic hepatitis C virus infection and non-alcoholic fatty liver disease induce a significant upregulation of serum acid sphingomyelinase which appears as a novel biomarker in chronic hepatopathies. Further studies are required to elucidate the potential of the sphingolipid signaling pathway as putative therapeutic target in chronic liver disease.
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Affiliation(s)
- Georgios Grammatikos
- Pharmazentrum Frankfurt, Institut für Allgemeine Pharmakologie und Toxikologie, Frankfurt am Main, Germany; Goethe University Hospital, Medizinische Klinik 1, Frankfurt am Main, Germany.
| | - Christiane Mühle
- Department of Psychiatry and Psychotherapy, Friedrich-Alexander-University Erlangen-Nuremberg, Germany
| | - Nerea Ferreiros
- Pharmazentrum Frankfurt, Institut für klinische Pharmakologie, Goethe University Hospital, Frankfurt am Main, Germany
| | - Sirkka Schroeter
- Pharmazentrum Frankfurt, Institut für Allgemeine Pharmakologie und Toxikologie, Frankfurt am Main, Germany; Goethe University Hospital, Medizinische Klinik 1, Frankfurt am Main, Germany
| | - Dimitra Bogdanou
- Goethe University Hospital, Medizinische Klinik 1, Frankfurt am Main, Germany
| | - Stephanie Schwalm
- Pharmazentrum Frankfurt, Institut für Allgemeine Pharmakologie und Toxikologie, Frankfurt am Main, Germany
| | - Gudrun Hintereder
- Zentrallabor, Goethe University Hospital, Frankfurt am Main, Germany
| | - Johannes Kornhuber
- Department of Psychiatry and Psychotherapy, Friedrich-Alexander-University Erlangen-Nuremberg, Germany
| | - Stefan Zeuzem
- Goethe University Hospital, Medizinische Klinik 1, Frankfurt am Main, Germany
| | - Christoph Sarrazin
- Goethe University Hospital, Medizinische Klinik 1, Frankfurt am Main, Germany
| | - Josef Pfeilschifter
- Pharmazentrum Frankfurt, Institut für Allgemeine Pharmakologie und Toxikologie, Frankfurt am Main, Germany
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The self-interaction of a nodavirus replicase is enhanced by mitochondrial membrane lipids. PLoS One 2014; 9:e89628. [PMID: 24586921 PMCID: PMC3934934 DOI: 10.1371/journal.pone.0089628] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Accepted: 01/22/2014] [Indexed: 12/24/2022] Open
Abstract
RNA replication of positive-strand (+)RNA viruses requires the protein-protein interactions among viral replicases and the association of viral replicases with intracellular membranes. Protein A from Wuhan nodavirus (WhNV), which closely associate with mitochondrial membranes, is the sole replicase required for viral RNA replication. Here, we studied the direct effects of mitochondrial membrane lipids (MMLs) on WhNV protein A activity in vitro. Our investigations revealed the self-interaction of WhNV protein A is accomplished via two different patterns (i.e., homotypic and heterotypic self-interactions via different interfaces). MMLs stimulated the protein A self-interaction, and this stimulation exhibited selectivity for specific phospholipids. Moreover, we found that specific phospholipids differently favor the two self-interaction patterns. Furthermore, manipulating specific phospholipid metabolism affected protein A self-interaction and the activity of protein A to replicate RNA in cells. Taken together, our findings reveal the direct effects of membrane lipids on a nodaviral RNA replicase.
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47
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Hepatitis C virus, cholesterol and lipoproteins--impact for the viral life cycle and pathogenesis of liver disease. Viruses 2013; 5:1292-324. [PMID: 23698400 PMCID: PMC3712309 DOI: 10.3390/v5051292] [Citation(s) in RCA: 101] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2013] [Revised: 04/10/2013] [Accepted: 04/27/2013] [Indexed: 02/07/2023] Open
Abstract
Hepatitis C virus (HCV) is a leading cause of chronic liver disease, including chronic hepatitis, fibrosis, cirrhosis, and hepatocellular carcinoma. Hepatitis C infection associates with lipid and lipoprotein metabolism disorders such as hepatic steatosis, hypobetalipoproteinemia, and hypocholesterolemia. Furthermore, virus production is dependent on hepatic very-low-density lipoprotein (VLDL) assembly, and circulating virions are physically associated with lipoproteins in complexes termed lipoviral particles. Evidence has indicated several functional roles for the formation of these complexes, including co-opting of lipoprotein receptors for attachment and entry, concealing epitopes to facilitate immune escape, and hijacking host factors for HCV maturation and secretion. Here, we review the evidence surrounding pathogenesis of the hepatitis C infection regarding lipoprotein engagement, cholesterol and triglyceride regulation, and the molecular mechanisms underlying these effects.
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48
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Biological functions of sphingomyelins. Prog Lipid Res 2013; 52:424-37. [PMID: 23684760 DOI: 10.1016/j.plipres.2013.05.001] [Citation(s) in RCA: 219] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Revised: 04/12/2013] [Accepted: 05/02/2013] [Indexed: 12/14/2022]
Abstract
Sphingomyelin (SM) is a dominant sphingolipid in membranes of mammalian cells and this lipid class is specifically enriched in the plasma membrane, the endocytic recycling compartment, and the trans Golgi network. The distribution of SM and cholesterol among cellular compartments correlate. Sphingolipids have extensive hydrogen-bonding capabilities which together with their saturated nature facilitate the formation of sphingolipid and SM-enriched lateral domains in membranes. Cholesterol prefers to interact with SMs and this interaction has many important functional consequences. In this review, the synthesis, regulation, and intracellular distribution of SMs are discussed. The many direct roles played by membrane SM in various cellular functions and processes will also be discussed. These include involvement in the regulation of endocytosis and receptor-mediated ligand uptake, in ion channel and G-protein coupled receptor function, in protein sorting, and functioning as receptor molecules for various bacterial toxins, and for non-bacterial pore-forming toxins. SM is also an important constituent of the eye lens membrane, and is believed to participate in the regulation of various nuclear functions. SM is an independent risk factor in the development of cardiovascular disease, and new studies have shed light on possible mechanism behind its role in atherogenesis.
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49
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Paul D, Bartenschlager R. Architecture and biogenesis of plus-strand RNA virus replication factories. World J Virol 2013; 2:32-48. [PMID: 24175228 PMCID: PMC3785047 DOI: 10.5501/wjv.v2.i2.32] [Citation(s) in RCA: 208] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/05/2012] [Revised: 01/18/2013] [Accepted: 01/24/2013] [Indexed: 02/05/2023] Open
Abstract
Plus-strand RNA virus replication occurs in tight association with cytoplasmic host cell membranes. Both, viral and cellular factors cooperatively generate distinct organelle-like structures, designated viral replication factories. This compartmentalization allows coordination of the different steps of the viral replication cycle, highly efficient genome replication and protection of the viral RNA from cellular defense mechanisms. Electron tomography studies conducted during the last couple of years revealed the three dimensional structure of numerous plus-strand RNA virus replication compartments and highlight morphological analogies between different virus families. Based on the morphology of virus-induced membrane rearrangements, we propose two separate subclasses: the invaginated vesicle/spherule type and the double membrane vesicle type. This review discusses common themes and distinct differences in the architecture of plus-strand RNA virus-induced membrane alterations and summarizes recent progress that has been made in understanding the complex interplay between viral and co-opted cellular factors in biogenesis and maintenance of plus-strand RNA virus replication factories.
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Different mechanisms of hepatitis C virus RNA polymerase activation by cyclophilin A and B in vitro. Biochim Biophys Acta Gen Subj 2012; 1820:1886-92. [PMID: 22954804 DOI: 10.1016/j.bbagen.2012.08.017] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2012] [Revised: 07/25/2012] [Accepted: 08/21/2012] [Indexed: 01/27/2023]
Abstract
BACKGROUND Cyclophilins (CyPs) are cellular proteins that are essential to hepatitis C virus (HCV) replication. Since cyclosporine A was discovered to inhibit HCV infection, the CyP pathway contributing to HCV replication is a potential attractive stratagem for controlling HCV infection. Among them, CyPA is accepted to interact with HCV nonstructural protein (NS) 5A, although interaction of CyPB and NS5B, an RNA-dependent RNA polymerase (RdRp), was proposed first. METHODS CyPA, CyPB, and HCV RdRp were expressed in bacteria and purified using combination column chromatography. HCV RdRp activity was analyzed in vitro with purified CyPA and CyPB. RESULTS CyPA at a high concentration (50× higher than that of RdRp) but not at low concentration activated HCV RdRp. CyPB had an allosteric effect on genotype 1b RdRp activation. CyPB showed genotype specificity and activated genotype 1b and J6CF (2a) RdRps but not genotype 1a or JFH1 (2a) RdRps. CyPA activated RdRps of genotypes 1a, 1b, and 2a. CyPB may also support HCV genotype 1b replication within the infected cells, although its knockdown effect on HCV 1b replicon activity was controversial in earlier reports. CONCLUSIONS CyPA activated HCV RdRp at the early stages of transcription, including template RNA binding. CyPB also activated genotype 1b RdRp. However, their activation mechanisms are different. GENERAL SIGNIFICANCE These data suggest that both CyPA and CyPB are excellent targets for the treatment of HCV 1b, which shows the greatest resistance to interferon and ribavirin combination therapy.
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