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Lee Y, Fracassi A, Devaraj NK. Control of giant vesicle assemblies by stimuli-responsive lipids. Chem Commun (Camb) 2024; 60:3930-3933. [PMID: 38497420 DOI: 10.1039/d4cc00322e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/19/2024]
Abstract
We describe a bottom-up synthesis of giant vesicles (GVs) utilizing an artificial stimuli-responsive diazobenzene lipid building block. Controlled by light, the GVs can exhibit dynamic behaviors, including reversible formation, the generation of highly multilamellar assemblies, and vesicle capturing and releasing events.
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Affiliation(s)
- Youngjun Lee
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, USA.
| | - Alessandro Fracassi
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, USA.
| | - Neal K Devaraj
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, USA.
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2
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The Bovine Seminal Plasma Protein PDC-109 Possesses Pan-Antiviral Activity. Viruses 2022; 14:v14092031. [PMID: 36146836 PMCID: PMC9504757 DOI: 10.3390/v14092031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Revised: 09/08/2022] [Accepted: 09/08/2022] [Indexed: 11/16/2022] Open
Abstract
Mammalian seminal plasma contains a multitude of bioactive components, including lipids, glucose, mineral elements, metabolites, proteins, cytokines, and growth factors, with various functions during insemination and fertilization. The seminal plasma protein PDC-109 is one of the major soluble components of the bovine ejaculate and is crucially important for sperm motility, capacitation, and acrosome reaction. A hitherto underappreciated function of seminal plasma is its anti-microbial and antiviral activity, which may limit the sexual transmission of infectious diseases during intercourse. We have recently discovered that PDC-109 inhibits the membrane fusion activity of influenza virus particles and significantly impairs viral infections at micromolar concentrations. Here we investigated whether the antiviral activity of PDC-109 is restricted to Influenza or if other mammalian viruses are similarly affected. We focused on Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2), the etiological agent of the Coronavirus Disease 19 (COVID-19), thoroughly assessing PDC-109 inhibition with SARS-CoV-2 Spike (S)-pseudotyped reporter virus particles, but also live-virus infections. Consistent with our previous publications, we found significant virus inhibition, albeit accompanied by substantial cytotoxicity. However, using time-of-addition experiments we discovered a treatment regimen that enables virus suppression without affecting cell viability. We furthermore demonstrated that PDC-109 is also able to impair infections mediated by the VSV glycoprotein (VSVg), thus indicating a broad pan-antiviral activity against multiple virus species and families.
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3
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Dymek M, Sikora E. Liposomes as biocompatible and smart delivery systems – The current state. Adv Colloid Interface Sci 2022; 309:102757. [DOI: 10.1016/j.cis.2022.102757] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 08/12/2022] [Accepted: 08/16/2022] [Indexed: 11/01/2022]
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4
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Schultz C, Farley SE, Tafesse FG. "Flash & Click": Multifunctionalized Lipid Derivatives as Tools To Study Viral Infections. J Am Chem Soc 2022; 144:13987-13995. [PMID: 35900117 PMCID: PMC9377334 DOI: 10.1021/jacs.2c02705] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In this perspective article, we describe the current status of lipid tools for studying host lipid-virus interactions at the cellular level. We discuss the potential lipidomic changes that viral infections impose on host cells and then outline the tools available and the resulting options to investigate the host cell lipid interactome. The future outcome will reveal new targets for treating virus infections.
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Affiliation(s)
- Carsten Schultz
- Department of Chemical Physiology and Biochemistry, Oregon Health & Science University; 3181 S.W. Sam Jackson Park Road, Portland, Oregon 97239-3098, United States
| | - Scotland E Farley
- Department of Chemical Physiology and Biochemistry, Oregon Health & Science University; 3181 S.W. Sam Jackson Park Road, Portland, Oregon 97239-3098, United States.,Department of Molecular Microbiology and Immunology, Oregon Health & Science University; 3181 S.W. Sam Jackson Park Road, Portland, Oregon 97239-3098, United States
| | - Fikadu G Tafesse
- Department of Molecular Microbiology and Immunology, Oregon Health & Science University; 3181 S.W. Sam Jackson Park Road, Portland, Oregon 97239-3098, United States
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5
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Joardar A, Pattnaik GP, Chakraborty H. Mechanism of Membrane Fusion: Interplay of Lipid and Peptide. J Membr Biol 2022; 255:211-224. [PMID: 35435451 PMCID: PMC9014786 DOI: 10.1007/s00232-022-00233-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Accepted: 03/25/2022] [Indexed: 11/26/2022]
Abstract
Membrane fusion is an essential process for the survival of eukaryotes and the entry of enveloped viruses into host cells. A proper understanding of the mechanism of membrane fusion would provide us a handle to manipulate several biological pathways, and design efficient vaccines against emerging and re-emerging viral infections. Although fusion proteins take the central stage in catalyzing the process, role of lipid composition is also of paramount importance. Lipid composition modulates membrane organization and dynamics and impacts the lipid–protein (peptide) interaction. Moreover, the intrinsic curvature of lipids has strong impact on the formation of stalk and hemifusion diaphragm. Detection of transiently stable intermediates remains the bottleneck in the understanding of fusion mechanism. In order to circumvent this challenge, analytical methods can be employed to determine the kinetic parameters from ensemble average measurements of observables, such as lipid mixing, content mixing, and content leakage. The current review aims to present an analytical method that would aid our understanding of the fusion mechanism, provides a better insight into the role of lipid shape, and discusses the interplay of lipid and peptide in membrane fusion.
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Affiliation(s)
- Ankita Joardar
- School of Chemistry, Sambalpur University, Jyoti Vihar, Burla, Odisha, 768019, India
| | | | - Hirak Chakraborty
- School of Chemistry, Sambalpur University, Jyoti Vihar, Burla, Odisha, 768019, India.
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6
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Zhang Z, He H, Yan M, Zhao C, Lei C, Li J, Yan F. Widely targeted analysis of metabolomic changes of Cucumis sativus induced by cucurbit chlorotic yellows virus. BMC PLANT BIOLOGY 2022; 22:158. [PMID: 35361125 PMCID: PMC8969345 DOI: 10.1186/s12870-022-03555-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Accepted: 03/22/2022] [Indexed: 05/03/2023]
Abstract
BACKGROUND Plant metabolites play vital roles in regulating the behavior of herbivore insects. Virus infection can universally alter plant metabolites to manipulate the orientation and feeding behaviors of insect vector, to favor the transmission of virus. Thus, determining the differentially accumulated metabolites of plant upon virus infection could provide insights into understanding how the triple interactions among plant, virus and insect vector happens. Our previous studies have found that vector whitefly Bemisia tabaci (Gennadius, Hemiptera: Aleyrodidae) showed different orientation behavior and performance on CCYV-infected and healthy cucumber plants. Cucurbit chlorotic yellows virus (CCYV) is exclusively transmitted by B. tabaci in a semi-persistent mode. In this study, we take the CCYV, B. tabaci and cucumber as a research system to explore the functions of phyto-metabolites in the triple interactions. RESULTS A total of 612 metabolites changed upon CCYV infection were monitored. Metabolites mainly enriched in flavonoids, lipids, nucleotides and their derivatives. At 7 days post CCYV inoculation (dpi), the contents of lipids, terpenoids and flavonoids remarkably decreased, while amino acids, nucleotides and their derivatives notably up-accumulated. At 15 dpi, the accumulation of flavonoids were still significantly reduced upon CCYV infection, while lipids, amino acids, nucleotides and derivatives were remarkably enhanced. Most of significantly increased metabolites were lipids (lysophosphatidylethanolamine, LPE; lysophosphatidylcholine, LPC and their isomers). Also, the number of significantly changed metabolites increased with the infection period. However, only a few organic acids and phenolic acids showed difference between CCYV-infected and healthy cucumber plants. CONCLUSIONS CCYV infection repressed the defensive flavonoids, terpeneoids metabolism but triggered the lipids, amino acids and nucleotides metabolism with the inoculation period. This result suggests that CCYV-infection makes cucumber plants more susceptible for whiteflies attack and CCYV infection. The reduction of defensive comounds and the increase of amino acids may be partially responsible for enhancing feeding preference of whiteflies to CCYV-infected hosts. CCYV may hijacked lipid metabolism for virus replication and assembly.
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Affiliation(s)
- Zelong Zhang
- College of Plant Protection, Henan Agricultural University, Zhengzhou, 450002 Henan China
| | - Haifang He
- College of Plant Protection, Henan Agricultural University, Zhengzhou, 450002 Henan China
| | - Minghui Yan
- College of Plant Protection, Henan Agricultural University, Zhengzhou, 450002 Henan China
| | - Chenchen Zhao
- College of Plant Protection, Henan Agricultural University, Zhengzhou, 450002 Henan China
| | - Caiyan Lei
- College of Plant Protection, Henan Agricultural University, Zhengzhou, 450002 Henan China
| | - Jingjing Li
- College of Plant Protection, Henan Agricultural University, Zhengzhou, 450002 Henan China
| | - Fengming Yan
- College of Plant Protection, Henan Agricultural University, Zhengzhou, 450002 Henan China
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7
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Farfan-Morales CN, Cordero-Rivera CD, Reyes-Ruiz JM, Hurtado-Monzón AM, Osuna-Ramos JF, González-González AM, De Jesús-González LA, Palacios-Rápalo SN, Del Ángel RM. Anti-flavivirus Properties of Lipid-Lowering Drugs. Front Physiol 2021; 12:749770. [PMID: 34690817 PMCID: PMC8529048 DOI: 10.3389/fphys.2021.749770] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Accepted: 09/20/2021] [Indexed: 12/11/2022] Open
Abstract
Although Flaviviruses such as dengue (DENV) and zika (ZIKV) virus are important human pathogens, an effective vaccine or antiviral treatment against them is not available. Hence, the search for new strategies to control flavivirus infections is essential. Several studies have shown that the host lipid metabolism could be an antiviral target because cholesterol and other lipids are required during the replicative cycle of different Flaviviridae family members. FDA-approved drugs with hypolipidemic effects could be an alternative for treating flavivirus infections. However, a better understanding of the regulation between host lipid metabolism and signaling pathways triggered during these infections is required. The metabolic pathways related to lipid metabolism modified during DENV and ZIKV infection are analyzed in this review. Additionally, the role of lipid-lowering drugs as safe host-targeted antivirals is discussed.
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Affiliation(s)
- Carlos Noe Farfan-Morales
- Department of Infectomics and Molecular Pathogenesis, Center for Research and Advanced Studies (CINVESTAV-IPN), Mexico City, Mexico
| | - Carlos Daniel Cordero-Rivera
- Department of Infectomics and Molecular Pathogenesis, Center for Research and Advanced Studies (CINVESTAV-IPN), Mexico City, Mexico
| | - José Manuel Reyes-Ruiz
- Unidad Médica de Alta Especialidad, Hospital de Especialidades No. 14, Centro Médico Nacional "Adolfo Ruiz Cortines," Instituto Mexicano del Seguro Social, Heroica Veracruz, Mexico
| | - Arianna M Hurtado-Monzón
- Department of Infectomics and Molecular Pathogenesis, Center for Research and Advanced Studies (CINVESTAV-IPN), Mexico City, Mexico
| | - Juan Fidel Osuna-Ramos
- Department of Infectomics and Molecular Pathogenesis, Center for Research and Advanced Studies (CINVESTAV-IPN), Mexico City, Mexico
| | - Arely M González-González
- Laboratorio de Ingeniería Tisular y Medicina Traslacional, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México (UNAM), Mexico City, Mexico
| | - Luis Adrián De Jesús-González
- Department of Infectomics and Molecular Pathogenesis, Center for Research and Advanced Studies (CINVESTAV-IPN), Mexico City, Mexico
| | - Selvin Noé Palacios-Rápalo
- Department of Infectomics and Molecular Pathogenesis, Center for Research and Advanced Studies (CINVESTAV-IPN), Mexico City, Mexico
| | - Rosa María Del Ángel
- Department of Infectomics and Molecular Pathogenesis, Center for Research and Advanced Studies (CINVESTAV-IPN), Mexico City, Mexico
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8
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Guo X, Steinkühler J, Marin M, Li X, Lu W, Dimova R, Melikyan GB. Interferon-Induced Transmembrane Protein 3 Blocks Fusion of Diverse Enveloped Viruses by Altering Mechanical Properties of Cell Membranes. ACS NANO 2021; 15:8155-8170. [PMID: 33656312 PMCID: PMC8159881 DOI: 10.1021/acsnano.0c10567] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Interferon-induced transmembrane protein 3 (IFITM3) potently inhibits entry of diverse enveloped viruses by trapping the viral fusion at a hemifusion stage, but the underlying mechanism remains unclear. Here, we show that recombinant IFITM3 reconstituted into lipid vesicles induces negative membrane curvature and that this effect maps to its small amphipathic helix (AH). We demonstrate that AH (i) partitions into lipid-disordered domains where IAV fusion occurs, (ii) induces negative membrane curvature, and (iii) increases lipid order and membrane stiffness. These effects on membrane properties correlate with the fusion-inhibitory activity, as targeting the ectopically expressed AH peptide to the cytoplasmic leaflet of the cell plasma membrane diminishes IAV-cell surface fusion induced by exposure to acidic pH. Our results thus imply that IFITM3 inhibits the transition from hemifusion to full fusion by imposing an unfavorable membrane curvature and increasing the order and stiffness of the cytoplasmic leaflet of endosomal membranes. Our findings reveal a universal mechanism by which cells block entry of diverse enveloped viruses.
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Affiliation(s)
- Xiangyang Guo
- Department of Pediatrics, Emory University School of Medicine, Atlanta, GA 30322, United States
| | - Jan Steinkühler
- Max Planck Institute of Colloids and Interfaces, 14424 Potsdam, Germany
| | - Mariana Marin
- Department of Pediatrics, Emory University School of Medicine, Atlanta, GA 30322, United States
| | - Xiang Li
- School of Pharmacy, Second Military Medical University, Shanghai, 200433, China
| | - Wuyuan Lu
- Institute of Human Virology and Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, Maryland 21201, United States
| | - Rumiana Dimova
- Max Planck Institute of Colloids and Interfaces, 14424 Potsdam, Germany
| | - Gregory B. Melikyan
- Department of Pediatrics, Emory University School of Medicine, Atlanta, GA 30322, United States
- Children’s Healthcare of Atlanta, Atlanta, GA 30322, USA
- Corresponding author: Gregory B. Melikyan,
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9
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Puhl AC, Fritch EJ, Lane TR, Tse LV, Yount BL, Sacramento CQ, Fintelman-Rodrigues N, Tavella TA, Maranhão Costa FT, Weston S, Logue J, Frieman M, Premkumar L, Pearce KH, Hurst BL, Andrade CH, Levi JA, Johnson NJ, Kisthardt SC, Scholle F, Souza TML, Moorman NJ, Baric RS, Madrid PB, Ekins S. Repurposing the Ebola and Marburg Virus Inhibitors Tilorone, Quinacrine, and Pyronaridine: In Vitro Activity against SARS-CoV-2 and Potential Mechanisms. ACS OMEGA 2021; 6:7454-7468. [PMID: 33778258 PMCID: PMC7992063 DOI: 10.1021/acsomega.0c05996] [Citation(s) in RCA: 48] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Accepted: 03/02/2021] [Indexed: 05/11/2023]
Abstract
Severe acute respiratory coronavirus 2 (SARS-CoV-2) is a newly identified virus that has resulted in over 2.5 million deaths globally and over 116 million cases globally in March, 2021. Small-molecule inhibitors that reverse disease severity have proven difficult to discover. One of the key approaches that has been widely applied in an effort to speed up the translation of drugs is drug repurposing. A few drugs have shown in vitro activity against Ebola viruses and demonstrated activity against SARS-CoV-2 in vivo. Most notably, the RNA polymerase targeting remdesivir demonstrated activity in vitro and efficacy in the early stage of the disease in humans. Testing other small-molecule drugs that are active against Ebola viruses (EBOVs) would appear a reasonable strategy to evaluate their potential for SARS-CoV-2. We have previously repurposed pyronaridine, tilorone, and quinacrine (from malaria, influenza, and antiprotozoal uses, respectively) as inhibitors of Ebola and Marburg viruses in vitro in HeLa cells and mouse-adapted EBOV in mice in vivo. We have now tested these three drugs in various cell lines (VeroE6, Vero76, Caco-2, Calu-3, A549-ACE2, HUH-7, and monocytes) infected with SARS-CoV-2 as well as other viruses (including MHV and HCoV 229E). The compilation of these results indicated considerable variability in antiviral activity observed across cell lines. We found that tilorone and pyronaridine inhibited the virus replication in A549-ACE2 cells with IC50 values of 180 nM and IC50 198 nM, respectively. We used microscale thermophoresis to test the binding of these molecules to the spike protein, and tilorone and pyronaridine bind to the spike receptor binding domain protein with K d values of 339 and 647 nM, respectively. Human Cmax for pyronaridine and quinacrine is greater than the IC50 observed in A549-ACE2 cells. We also provide novel insights into the mechanism of these compounds which is likely lysosomotropic.
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Affiliation(s)
- Ana C. Puhl
- Collaborations
Pharmaceuticals, Inc., 840 Main Campus Drive, Lab 3510, Raleigh, North Carolina 27606, United States
| | - Ethan J. Fritch
- Department
of Microbiology and Immunology, University
of North Carolina School of Medicine, Chapel Hill, North Carolina 27599, United States
| | - Thomas R. Lane
- Collaborations
Pharmaceuticals, Inc., 840 Main Campus Drive, Lab 3510, Raleigh, North Carolina 27606, United States
| | - Longping V. Tse
- Department
of Epidemiology, University of North Carolina
School of Medicine, Chapel Hill, North Carolina 27599, United States
| | - Boyd L. Yount
- Department
of Epidemiology, University of North Carolina
School of Medicine, Chapel Hill, North Carolina 27599, United States
| | - Carolina Q. Sacramento
- Laboratório
de Imunofarmacologia, Instituto Oswaldo Cruz (IOC), Fundação Oswaldo Cruz (Fiocruz), Rio de Janeiro, RJ 21040-900, Brazil
- Centro
De Desenvolvimento Tecnológico Em Saúde (CDTS), Fiocruz, Rio de
Janeiro 21040-900, Brazil
| | - Natalia Fintelman-Rodrigues
- Laboratório
de Imunofarmacologia, Instituto Oswaldo Cruz (IOC), Fundação Oswaldo Cruz (Fiocruz), Rio de Janeiro, RJ 21040-900, Brazil
- Centro
De Desenvolvimento Tecnológico Em Saúde (CDTS), Fiocruz, Rio de
Janeiro 21040-900, Brazil
| | - Tatyana Almeida Tavella
- Laboratory
of Tropical Diseases—Prof. Dr. Luiz Jacinto da Silva, Department
of Genetics, Evolution, Microbiology and Immunology, University of Campinas-UNICAMP, Campinas, São Paulo 13083-970, Brazil
| | - Fabio Trindade Maranhão Costa
- Laboratory
of Tropical Diseases—Prof. Dr. Luiz Jacinto da Silva, Department
of Genetics, Evolution, Microbiology and Immunology, University of Campinas-UNICAMP, Campinas, São Paulo 13083-970, Brazil
| | - Stuart Weston
- Department
of Microbiology and Immunology, University
of Maryland School of Medicine, Baltimore, Maryland 21201, United States
| | - James Logue
- Department
of Microbiology and Immunology, University
of Maryland School of Medicine, Baltimore, Maryland 21201, United States
| | - Matthew Frieman
- Department
of Microbiology and Immunology, University
of Maryland School of Medicine, Baltimore, Maryland 21201, United States
| | - Lakshmanane Premkumar
- Department
of Microbiology and Immunology, University
of North Carolina School of Medicine, Chapel Hill, North Carolina 27599, United States
| | - Kenneth H. Pearce
- Center
for Integrative Chemical Biology and Drug Discovery, Chemical Biology
and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, North Carolina 27599, United States
- UNC
Lineberger Comprehensive Cancer Center, Chapel Hill, North Carolina 27599, United States
| | - Brett L. Hurst
- Institute
for Antiviral Research, Utah State University, Logan, Utah 84322, United States
- Department of Animal, Dairy and Veterinary Sciences, Utah State University, Logan, Utah 84322, United States
| | - Carolina Horta Andrade
- Laboratory
of Tropical Diseases—Prof. Dr. Luiz Jacinto da Silva, Department
of Genetics, Evolution, Microbiology and Immunology, University of Campinas-UNICAMP, Campinas, São Paulo 13083-970, Brazil
- LabMol—Laboratory of Molecular Modeling
and Drug Design, Faculdade
de Farmácia, Universidade Federal
de Goiás, Goiânia,
GO 74605-170, Brazil
| | - James A. Levi
- Department of Biological Sciences, North
Carolina State University, Raleigh, North Carolina 27695, United States
| | - Nicole J. Johnson
- Department of Biological Sciences, North
Carolina State University, Raleigh, North Carolina 27695, United States
| | - Samantha C. Kisthardt
- Department of Biological Sciences, North
Carolina State University, Raleigh, North Carolina 27695, United States
| | - Frank Scholle
- Department of Biological Sciences, North
Carolina State University, Raleigh, North Carolina 27695, United States
| | - Thiago Moreno L. Souza
- Laboratório
de Imunofarmacologia, Instituto Oswaldo Cruz (IOC), Fundação Oswaldo Cruz (Fiocruz), Rio de Janeiro, RJ 21040-900, Brazil
- Centro
De Desenvolvimento Tecnológico Em Saúde (CDTS), Fiocruz, Rio de
Janeiro 21040-900, Brazil
| | - Nathaniel John Moorman
- Department
of Microbiology and Immunology, University
of North Carolina School of Medicine, Chapel Hill, North Carolina 27599, United States
- Center
for Integrative Chemical Biology and Drug Discovery, Chemical Biology
and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, North Carolina 27599, United States
- Rapidly Emerging Antiviral Drug Discovery
Initiative, University of North Carolina
at Chapel Hill, Chapel
Hill, North Carolina 27599, United States
| | - Ralph S. Baric
- Department
of Microbiology and Immunology, University
of North Carolina School of Medicine, Chapel Hill, North Carolina 27599, United States
- Department
of Epidemiology, University of North Carolina
School of Medicine, Chapel Hill, North Carolina 27599, United States
- Rapidly Emerging Antiviral Drug Discovery
Initiative, University of North Carolina
at Chapel Hill, Chapel
Hill, North Carolina 27599, United States
| | - Peter B. Madrid
- SRI International, 333 Ravenswood Avenue, Menlo Park, California 94025, United States
| | - Sean Ekins
- Collaborations
Pharmaceuticals, Inc., 840 Main Campus Drive, Lab 3510, Raleigh, North Carolina 27606, United States
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10
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Pattnaik GP, Chakraborty H. Fusogenic Effect of Cholesterol Prevails over the Inhibitory Effect of a Peptide-Based Membrane Fusion Inhibitor. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:3477-3489. [PMID: 33689373 DOI: 10.1021/acs.langmuir.1c00319] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Membrane fusion is the primary step in the entry of enveloped viruses into the host cell. Membrane composition modulates the membrane fusion by changing the organization dynamics of the fusion proteins, peptides, and membranes. The asymmetric lipid compositions of the viral envelope and the host cell influence the membrane fusion. Cholesterol is an important constituent of mammalian cells and plays a vital role in the entry of several viruses. In our pursuit of developing peptide-based general fusion inhibitors, we have previously shown that a coronin 1-derived peptide, TG-23, inhibited polyethylene glycol-induced fusion between symmetric membranes without cholesterol. In this work, we have studied the effect of TG-23 on the polyethylene glycol-mediated fusion between 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC), 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE), and 1,2-dioleoyl-sn-glycero-3-phospho-(1'-rac-glycerol) (DOPG) (60/30/10 mol %) and DOPC/DOPE/DOPG/CH (50/30/10/10 mol %) membranes and between DOPC/DOPE/DOPG (60/30/10 mol %) and DOPC/DOPE/DOPG/CH (40/30/10/20 mol %) membranes. Our results demonstrate that the TG-23 peptide inhibited the fusion between membranes containing 0 and 10 mol % cholesterol though the efficacy is less than that of symmetric fusion between membranes devoid of cholesterol, and the inhibitory efficacy becomes negligible in the fusion between membranes containing 0 and 20 mol % cholesterol. Several steady-state and time-resolved fluorescence spectroscopic techniques have been successfully utilized to evaluate the organization, dynamics, and membrane penetration of the TG-23 peptide. Taken together, our results demonstrate that the reduction of the inhibitory effect of TG-23 in asymmetric membrane fusion containing cholesterol of varying concentrations is not due to the altered peptide structure, organization, and dynamics, rather owing to the intrinsic negative curvature-inducing property of cholesterol. Therefore, the membrane composition is an added complexity in the journey of developing peptide-based membrane fusion inhibitors.
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Affiliation(s)
| | - Hirak Chakraborty
- School of Chemistry, Sambalpur University, Jyoti Vihar, Burla, Odisha 768 019, India
- Centre of Excellence in Natural Products and Therapeutics, Sambalpur University, Jyoti Vihar, Burla, Odisha 768 019, India
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11
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Sauter D, Kirchhoff F. Evolutionary conflicts and adverse effects of antiviral factors. eLife 2021; 10:e65243. [PMID: 33450175 PMCID: PMC7811402 DOI: 10.7554/elife.65243] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Accepted: 01/06/2021] [Indexed: 12/13/2022] Open
Abstract
Human cells are equipped with a plethora of antiviral proteins protecting them against invading viral pathogens. In contrast to apoptotic or pyroptotic cell death, which serves as ultima ratio to combat viral infections, these cell-intrinsic restriction factors may prevent or at least slow down viral spread while allowing the host cell to survive. Nevertheless, their antiviral activity may also have detrimental effects on the host. While the molecular mechanisms underlying the antiviral activity of restriction factors are frequently well investigated, potential undesired effects of their antiviral functions on the host cell are hardly explored. With a focus on antiretroviral proteins, we summarize in this review how individual restriction factors may exert adverse effects as trade-off for efficient defense against attacking pathogens.
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Affiliation(s)
- Daniel Sauter
- Institute of Molecular Virology, Ulm University Medical CenterUlmGermany
- Institute of Medical Virology and Epidemiology of Viral Diseases, University Hospital TübingenTübingenGermany
| | - Frank Kirchhoff
- Institute of Molecular Virology, Ulm University Medical CenterUlmGermany
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12
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Park A, Graceffa O, Rawle RJ. Kinetic Modeling of West Nile Virus Fusion Indicates an Off-Pathway State. ACS Infect Dis 2020; 6:3260-3268. [PMID: 33201665 DOI: 10.1021/acsinfecdis.0c00637] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
West Nile virus (WNV) is a prominent mosquito-borne flavivirus that causes febrile illness in humans. To infect host cells, WNV virions first bind to plasma membrane receptors, then initiate membrane fusion following endocytosis. The viral transmembrane E protein, triggered by endosomal pH, catalyzes fusion while undergoing a dimer-to-trimer transition. Previously, single-particle WNV fusion data was interrogated with a stochastic cellular automaton simulation, which modeled the E proteins during the fusion process. The results supported a linear fusion mechanism, with E protein trimerization being rate-limiting. Here, we present corrections to the previous simulation, and apply them to the WNV fusion data. We observe that a linear mechanism is no longer sufficient to fit the data. Instead, an off-pathway state is necessary; these results are corroborated by per virus chemical kinetics modeling. When compared with a similar Zika virus fusion model, this suggests that off-pathway fusion mechanisms may characterize flaviviruses more broadly.
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Affiliation(s)
- Abraham Park
- Department of Chemistry, Williams College, Williamstown, Massachusetts 01267, United States
| | - Olivia Graceffa
- Department of Chemistry, Williams College, Williamstown, Massachusetts 01267, United States
| | - Robert J. Rawle
- Department of Chemistry, Williams College, Williamstown, Massachusetts 01267, United States
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13
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Puhl AC, Fritch EJ, Lane TR, Tse LV, Yount BL, Sacramento CQ, Tavella TA, Costa FTM, Weston S, Logue J, Frieman M, Premkumar L, Pearce KH, Hurst BL, Andrade CH, Levi JA, Johnson NJ, Kisthardt SC, Scholle F, Souza TML, Moorman NJ, Baric RS, Madrid P, Ekins S. Repurposing the Ebola and Marburg Virus Inhibitors Tilorone, Quinacrine and Pyronaridine: In vitro Activity Against SARS-CoV-2 and Potential Mechanisms. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2020:2020.12.01.407361. [PMID: 33299990 PMCID: PMC7724658 DOI: 10.1101/2020.12.01.407361] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
SARS-CoV-2 is a newly identified virus that has resulted in over 1.3 M deaths globally and over 59 M cases globally to date. Small molecule inhibitors that reverse disease severity have proven difficult to discover. One of the key approaches that has been widely applied in an effort to speed up the translation of drugs is drug repurposing. A few drugs have shown in vitro activity against Ebola virus and demonstrated activity against SARS-CoV-2 in vivo . Most notably the RNA polymerase targeting remdesivir demonstrated activity in vitro and efficacy in the early stage of the disease in humans. Testing other small molecule drugs that are active against Ebola virus would seem a reasonable strategy to evaluate their potential for SARS-CoV-2. We have previously repurposed pyronaridine, tilorone and quinacrine (from malaria, influenza, and antiprotozoal uses, respectively) as inhibitors of Ebola and Marburg virus in vitro in HeLa cells and of mouse adapted Ebola virus in mouse in vivo . We have now tested these three drugs in various cell lines (VeroE6, Vero76, Caco-2, Calu-3, A549-ACE2, HUH-7 and monocytes) infected with SARS-CoV-2 as well as other viruses (including MHV and HCoV 229E). The compilation of these results indicated considerable variability in antiviral activity observed across cell lines. We found that tilorone and pyronaridine inhibited the virus replication in A549-ACE2 cells with IC 50 values of 180 nM and IC 50 198 nM, respectively. We have also tested them in a pseudovirus assay and used microscale thermophoresis to test the binding of these molecules to the spike protein. They bind to spike RBD protein with K d values of 339 nM and 647 nM, respectively. Human C max for pyronaridine and quinacrine is greater than the IC 50 hence justifying in vivo evaluation. We also provide novel insights into their mechanism which is likely lysosomotropic.
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Affiliation(s)
- Ana C. Puhl
- Collaborations Pharmaceuticals, Inc., 840 Main Campus Drive, Lab 3510, Raleigh, NC 27606, USA
| | - Ethan James Fritch
- Department of Microbiology and Immunology, University of North Carolina School of Medicine, Chapel Hill NC 27599, USA
| | - Thomas R. Lane
- Collaborations Pharmaceuticals, Inc., 840 Main Campus Drive, Lab 3510, Raleigh, NC 27606, USA
| | - Longping V. Tse
- Department of Epidemiology, University of North Carolina School of Medicine, Chapel Hill NC 27599, USA
| | - Boyd L. Yount
- Department of Epidemiology, University of North Carolina School of Medicine, Chapel Hill NC 27599, USA
| | - Carol Queiroz Sacramento
- Laboratório de Imunofarmacologia, Instituto Oswaldo Cruz (IOC), Fundação Oswaldo Cruz (Fiocruz), Rio de Janeiro, RJ, Brazil
- Centro De Desenvolvimento Tecnológico Em Saúde (CDTS), Fiocruz, Rio de Janeiro, Brasil
| | - Tatyana Almeida Tavella
- Laboratory of Tropical Diseases - Prof. Dr. Luiz Jacinto da Silva, Department of Genetics, Evolution, Microbiology and Immunology, University of Campinas-UNICAMP, Campinas, SP, Brazil
| | - Fabio Trindade Maranhão Costa
- Laboratory of Tropical Diseases - Prof. Dr. Luiz Jacinto da Silva, Department of Genetics, Evolution, Microbiology and Immunology, University of Campinas-UNICAMP, Campinas, SP, Brazil
| | - Stuart Weston
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - James Logue
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Matthew Frieman
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Lakshmanane Premkumar
- Department of Microbiology and Immunology, University of North Carolina School of Medicine, Chapel Hill NC 27599, USA
| | - Kenneth H. Pearce
- Center for Integrative Chemical Biology and Drug Discovery, Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, North Carolina 27599, USA
- UNC Lineberger Comprehensive Cancer Center, Chapel Hill, North Carolina 27599, USA
| | - Brett L. Hurst
- Institute for Antiviral Research, Utah State University, Logan, UT, USA
- Department of Animal, Dairy and Veterinary Sciences, Utah State University, Logan, UT, USA
| | - Carolina Horta Andrade
- Laboratory of Tropical Diseases - Prof. Dr. Luiz Jacinto da Silva, Department of Genetics, Evolution, Microbiology and Immunology, University of Campinas-UNICAMP, Campinas, SP, Brazil
- LabMol - Laboratory of Molecular Modeling and Drug Design, Faculdade de Farmácia, Universidade Federal de Goiás, Goiânia, GO, 74605-170, Brazil
| | - James A. Levi
- Department of Biological Sciences, North Carolina State University, Raleigh, NC, USA
| | - Nicole J. Johnson
- Department of Biological Sciences, North Carolina State University, Raleigh, NC, USA
| | - Samantha C. Kisthardt
- Department of Biological Sciences, North Carolina State University, Raleigh, NC, USA
| | - Frank Scholle
- Department of Biological Sciences, North Carolina State University, Raleigh, NC, USA
| | - Thiago Moreno L. Souza
- Laboratório de Imunofarmacologia, Instituto Oswaldo Cruz (IOC), Fundação Oswaldo Cruz (Fiocruz), Rio de Janeiro, RJ, Brazil
- Centro De Desenvolvimento Tecnológico Em Saúde (CDTS), Fiocruz, Rio de Janeiro, Brasil
| | - Nathaniel John Moorman
- Department of Microbiology and Immunology, University of North Carolina School of Medicine, Chapel Hill NC 27599, USA
- Center for Integrative Chemical Biology and Drug Discovery, Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, North Carolina 27599, USA
- Rapidly Emerging Antiviral Drug Discovery Initiative, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Ralph S. Baric
- Department of Microbiology and Immunology, University of North Carolina School of Medicine, Chapel Hill NC 27599, USA
- Department of Epidemiology, University of North Carolina School of Medicine, Chapel Hill NC 27599, USA
- Rapidly Emerging Antiviral Drug Discovery Initiative, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Peter Madrid
- SRI International, 333 Ravenswood Avenue, Menlo Park, CA 94025, USA
| | - Sean Ekins
- Collaborations Pharmaceuticals, Inc., 840 Main Campus Drive, Lab 3510, Raleigh, NC 27606, USA
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14
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Abstract
The process of entry into a host cell is a key step in the life cycle of most viruses. In recent years, there has been a significant increase in our understanding of the routes and mechanisms of entry for a number of these viruses. This has led to the development of novel broad-spectrum antiviral approaches that target host cell proteins and pathways, in addition to strategies focused on individual viruses or virus families. Here we consider a number of these approaches and their broad-spectrum potential.
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Affiliation(s)
- Michela Mazzon
- MRC Laboratory for Molecular Cell Biology, University College London, London, UK
| | - Mark Marsh
- MRC Laboratory for Molecular Cell Biology, University College London, London, UK
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15
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Welke RW, Haralampiev I, Schröter F, Braun BC, Herrmann A, Sieben C, Müller P. Inhibition of influenza virus activity by the bovine seminal plasma protein PDC-109. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2019; 48:503-511. [PMID: 31222413 DOI: 10.1007/s00249-019-01374-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Revised: 03/12/2019] [Accepted: 06/09/2019] [Indexed: 12/19/2022]
Abstract
A number of viruses causing sexually transmissible diseases are transmitted via mammalian seminal plasma. Several components of seminal plasma have been shown to influence those viruses and their physiological impact. To unravel whether components of seminal plasma could affect viruses transmitted via other pathways, it was investigated here whether the bovine seminal plasma protein PDC-109, belonging to the Fn-type 2 protein family, influences the activity of influenza A viruses, used as a model for enveloped viruses. We found that PDC-109 inhibits the fusion of influenza virus with human erythrocyte membranes and leads to a decreased viral infection in MDCK cells. In the presence of the head group of the phospholipid phosphatidylcholine, phosphorylcholine, the inhibitory effect of PDC-109 was attenuated. This indicates that the impact of the protein is mainly caused by its binding to viral and to erythrocyte membranes thereby interfering with virus-cell binding. Our study underlines that Fn-type 2 proteins have to be considered as new antiviral components present in mammalian seminal plasma.
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Affiliation(s)
- Robert-William Welke
- Institute for Biology, Humboldt-Universität zu Berlin, Invalidenstr. 42, 10115, Berlin, Germany.,Department of Intracellular Proteolysis, Max Delbrück Center for Molecular Medicine, Robert-Rössle-Str. 10, 13125, Berlin, Germany
| | - Ivan Haralampiev
- Institute for Biology, Humboldt-Universität zu Berlin, Invalidenstr. 42, 10115, Berlin, Germany.,Department of Crystallography, Max Delbrück Center for Molecular Medicine, Robert-Rössle-Str. 10, 13125, Berlin, Germany
| | - Filip Schröter
- Leibniz Institute for Zoo and Wildlife Research, Alfred-Kowalke-Straße 17, 10315, Berlin, Germany.,Department of Cardiovascular Surgery, Heart Center Brandenburg, Brandenburg Medical School "Theodor-Fontane", Ladeburger Straße 17, 16321, Bernau, Germany
| | - Beate C Braun
- Leibniz Institute for Zoo and Wildlife Research, Alfred-Kowalke-Straße 17, 10315, Berlin, Germany
| | - Andreas Herrmann
- Institute for Biology, Humboldt-Universität zu Berlin, Invalidenstr. 42, 10115, Berlin, Germany
| | - Christian Sieben
- Institute for Biology, Humboldt-Universität zu Berlin, Invalidenstr. 42, 10115, Berlin, Germany. .,Laboratory for Experimental Biophysics, School of Basic Sciences, École Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland.
| | - Peter Müller
- Institute for Biology, Humboldt-Universität zu Berlin, Invalidenstr. 42, 10115, Berlin, Germany.
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16
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Functional Reconstitution of HlyB, a Type I Secretion ABC Transporter, in Saposin-A Nanoparticles. Sci Rep 2019; 9:8436. [PMID: 31182729 PMCID: PMC6558041 DOI: 10.1038/s41598-019-44812-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2018] [Accepted: 05/23/2019] [Indexed: 11/08/2022] Open
Abstract
Type I secretion systems (T1SS) are ubiquitous transport machineries in Gram-negative bacteria. They comprise a relatively simple assembly of three membrane-localised proteins: an inner-membrane complex composed of an ABC transporter and a membrane fusion protein, and a TolC-like outer membrane component. T1SS transport a wide variety of substrates with broad functional diversity. The ABC transporter hemolysin B (HlyB), for example, is part of the hemolysin A-T1SS in Escherichia coli. In contrast to canonical ABC transporters, an accessory domain, a C39 peptidase-like domain (CLD), is located at the N-terminus of HlyB and is essential for secretion. In this study, we have established an optimised purification protocol for HlyB and the subsequent reconstitution employing the saposin-nanoparticle system. We point out the negative influence of free detergent on the basal ATPase activity of HlyB, studied the influence of a lysolipid or lipid matrix on activity and present functional studies with the full-length substrate proHlyA in its folded and unfolded states, which both have a stimulatory effect on the ATPase activity.
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17
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Pulkkinen LIA, Butcher SJ, Anastasina M. Tick-Borne Encephalitis Virus: A Structural View. Viruses 2018; 10:v10070350. [PMID: 29958443 PMCID: PMC6071267 DOI: 10.3390/v10070350] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 06/25/2018] [Accepted: 06/27/2018] [Indexed: 12/11/2022] Open
Abstract
Tick-borne encephalitis virus (TBEV) is a growing health concern. It causes a severe disease that can lead to permanent neurological complications or death and the incidence of TBEV infections is constantly rising. Our understanding of TBEV’s structure lags behind that of other flaviviruses, but has advanced recently with the publication of a high-resolution structure of the TBEV virion. The gaps in our knowledge include: aspects of receptor binding, replication and virus assembly. Furthermore, TBEV has mostly been studied in mammalian systems, even though the virus’ interaction with its tick hosts is a central part of its life cycle. Elucidating these aspects of TBEV biology are crucial for the development of TBEV antivirals, as well as the improvement of diagnostics. In this review, we summarise the current structural knowledge on TBEV, bringing attention to the current gaps in our understanding, and propose further research that is needed to truly understand the structural-functional relationship of the virus and its hosts.
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Affiliation(s)
- Lauri I A Pulkkinen
- HiLIFE-Institute of Biotechnology, University of Helsinki, 00790 Helsinki, Finland.
- Faculty of Biological and Environmental Sciences, University of Helsinki, 00790 Helsinki, Finland.
| | - Sarah J Butcher
- HiLIFE-Institute of Biotechnology, University of Helsinki, 00790 Helsinki, Finland.
- Faculty of Biological and Environmental Sciences, University of Helsinki, 00790 Helsinki, Finland.
| | - Maria Anastasina
- HiLIFE-Institute of Biotechnology, University of Helsinki, 00790 Helsinki, Finland.
- Faculty of Biological and Environmental Sciences, University of Helsinki, 00790 Helsinki, Finland.
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18
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Hiwale AA, Voshavar C, Dharmalingam P, Dhayani A, Mukthavaram R, Nadella R, Sunnapu O, Gandhi S, Naidu VGM, Chaudhuri A, Marepally S, Vemula PK. Scaling the effect of hydrophobic chain length on gene transfer properties of di-alkyl, di-hydroxy ethylammonium chloride based cationic amphiphiles. RSC Adv 2017. [DOI: 10.1039/c7ra02271a] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Asymmetric hydrocarbon chains influence the efficiency of cationic lipids based liposomes in nucleic acid delivery. A systematic investigation of role of asymmetry in transfection efficiency.
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Affiliation(s)
- Ankita A. Hiwale
- Institute for Stem Cell Biology and Regenerative Medicine (inStem)
- Bengaluru 560065
- India
| | | | - Priya Dharmalingam
- Centre for Stem Cell Research
- Christian Medical College Campus
- Vellore 632002
- India
| | - Ashish Dhayani
- Institute for Stem Cell Biology and Regenerative Medicine (inStem)
- Bengaluru 560065
- India
| | - Rajesh Mukthavaram
- Translational Neuro-oncology Laboratories
- Moores Cancer Center
- University of California San Diego
- La Jolla
- USA
| | - Rasajna Nadella
- Centre for Stem Cell Research
- Christian Medical College Campus
- Vellore 632002
- India
| | - Omprakash Sunnapu
- National Institute for Pharmaceutical Education and Research
- Hyderabad 500018
- India
| | - Sivaraman Gandhi
- Institute for Stem Cell Biology and Regenerative Medicine (inStem)
- Bengaluru 560065
- India
| | - V. G. M. Naidu
- National Institute for Pharmaceutical Education and Research
- Hyderabad 500018
- India
| | - Arabinda Chaudhuri
- Biomaterials Group
- CSIR-Indian Institute of Chemical Technology
- Hyderabad 500 007
- India
| | - Srujan Marepally
- Institute for Stem Cell Biology and Regenerative Medicine (inStem)
- Bengaluru 560065
- India
- Centre for Stem Cell Research
- Christian Medical College Campus
| | - Praveen Kumar Vemula
- Institute for Stem Cell Biology and Regenerative Medicine (inStem)
- Bengaluru 560065
- India
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19
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Martín-Acebes MA, Vázquez-Calvo Á, Saiz JC. Lipids and flaviviruses, present and future perspectives for the control of dengue, Zika, and West Nile viruses. Prog Lipid Res 2016; 64:123-137. [PMID: 27702593 DOI: 10.1016/j.plipres.2016.09.005] [Citation(s) in RCA: 101] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Revised: 08/17/2016] [Accepted: 09/16/2016] [Indexed: 02/06/2023]
Abstract
Flaviviruses are emerging arthropod-borne pathogens that cause life-threatening diseases such as yellow fever, dengue, West Nile encephalitis, tick-borne encephalitis, Kyasanur Forest disease, tick-borne encephalitis, or Zika disease. This viral genus groups >50 viral species of small enveloped plus strand RNA virus that are phylogenetically closely related to hepatitis C virus. Importantly, the flavivirus life cycle is intimately associated to host cell lipids. Along this line, flaviviruses rearrange intracellular membranes from the endoplasmic-reticulum of the infected cells to develop adequate platforms for viral replication and particle biogenesis. Moreover, flaviviruses dramatically orchestrate a profound reorganization of the host cell lipid metabolism to create a favorable environment for viral multiplication. Consistently, recent work has shown the importance of specific lipid classes in flavivirus infections. For instances, fatty acid synthesis is linked to viral replication, phosphatidylserine and phosphatidylethanolamine are involved on the entry of flaviviruses, sphingolipids (ceramide and sphingomyelin) play a key role on virus assembly and pathogenesis, and cholesterol is essential for innate immunity evasion in flavivirus-infected cells. Here, we revise the current knowledge on the interactions of the flaviviruses with the cellular lipid metabolism to identify potential targets for future antiviral development aimed to combat these relevant health-threatening pathogens.
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Affiliation(s)
- Miguel A Martín-Acebes
- Department of Biotechnology, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Carretera de A Coruña km 7.5, 28040 Madrid, Spain.
| | - Ángela Vázquez-Calvo
- Department of Biotechnology, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Carretera de A Coruña km 7.5, 28040 Madrid, Spain
| | - Juan-Carlos Saiz
- Department of Biotechnology, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Carretera de A Coruña km 7.5, 28040 Madrid, Spain
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20
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Rogers DM, Kent MS, Rempe SB. Molecular basis of endosomal-membrane association for the dengue virus envelope protein. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2015; 1848:1041-52. [DOI: 10.1016/j.bbamem.2014.12.018] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Revised: 12/05/2014] [Accepted: 12/19/2014] [Indexed: 11/15/2022]
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21
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Chao LH, Klein DE, Schmidt AG, Peña JM, Harrison SC. Sequential conformational rearrangements in flavivirus membrane fusion. eLife 2014; 3:e04389. [PMID: 25479384 PMCID: PMC4293572 DOI: 10.7554/elife.04389] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2014] [Accepted: 12/04/2014] [Indexed: 01/08/2023] Open
Abstract
The West Nile Virus (WNV) envelope protein, E, promotes membrane fusion during viral cell entry by undergoing a low-pH triggered conformational reorganization. We have examined the mechanism of WNV fusion and sought evidence for potential intermediates during the conformational transition by following hemifusion of WNV virus-like particles (VLPs) in a single particle format. We have introduced specific mutations into E, to relate their influence on fusion kinetics to structural features of the protein. At the level of individual E subunits, trimer formation and membrane engagement of the threefold clustered fusion loops are rate-limiting. Hemifusion requires at least two adjacent trimers. Simulation of the kinetics indicates that availability of competent monomers within the contact zone between virus and target membrane makes trimerization a bottleneck in hemifusion. We discuss the implications of the model we have derived for mechanisms of membrane fusion in other contexts. DOI:http://dx.doi.org/10.7554/eLife.04389.001 Flaviviruses are a group of viruses that cause serious diseases in humans, including yellow fever, West Nile fever and dengue fever. Like all viruses, flaviviruses protect their genetic material with a protein shell and, like many other viruses, that shell also has a lipid membrane. Flaviruses use one of their surface membrane proteins, known as ‘envelope protein’ or simply ‘E’, to bind to the surface of host cells. Once the virus has attached to the host cell membrane, it becomes engulfed within a bubble-like structure called an endosome, which also has a surrounding membrane. The interior of an endosome is acidic. Under these conditions the E protein undergoes a series of changes that bring the two membranes into close contact, so that the membrane of the virus can fuse with the membrane of the endosome. This membrane fusion allows the genome of the virus to escape the endosome and hijack the cell to make new copies of the virus. The E proteins on a mature flavivirus particle are found in pairs, but previous work showed that these proteins must work together in groups of three (called ‘trimers’) for the viral and endosomal membranes to fuse. Chao et al. have now asked: what are the rate-limiting steps that lead to the formation of trimers? And how many trimers are necessary to cause the membranes to fuse? Chao et al. have investigated these questions using virus-like particles containing the E protein of West Nile Virus. They used techniques that can track individual particles, which their laboratory had previously used to investigate the influenza virus, to model changes in the E protein before, during and after membrane fusion. Chao et al. then made mutant versions of the envelope protein and used virus-like particles containing them to test the model. The data that Chao et al. obtained and computer simulations they carried out suggest that exposure to acidic conditions encourages the pairs of E proteins to separate and extend towards the endosome membrane. Individual E proteins then group together into trimers, and at least two trimers are needed to exert enough force to allow the membranes to fuse. The experimental design used by Chao et al. will now allow them to study the action of molecules that inhibit membrane fusion by West Nile Virus and other viruses. DOI:http://dx.doi.org/10.7554/eLife.04389.002
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Affiliation(s)
- Luke H Chao
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, United States
| | - Daryl E Klein
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, United States
| | - Aaron G Schmidt
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, United States
| | - Jennifer M Peña
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, United States
| | - Stephen C Harrison
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, United States
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22
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Godefroy C, Dahmane S, Dosset P, Adam O, Nicolai MC, Ronzon F, Milhiet PE. Mimicking influenza virus fusion using supported lipid bilayers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:11394-11400. [PMID: 25186242 DOI: 10.1021/la502591a] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Influenza virus infection is a serious public health problem in the world, and understanding the molecular mechanisms involved in viral replication is crucial. In this paper, we used a minimalist approach based on a lipid bilayer supported on mica, which we imaged by atomic force microscopy (AFM) in a physiological buffer, to analyze the different steps of influenza fusion, from the interaction of intact viruses with the supported bilayer to their complete fusion. Our results show that sialic acid recognition and priming upon acidification are sufficient for a complete fusion with the host cell membrane. After fusion, a flat and continuous membrane was observed. Because of the fragility of the viral membrane that was removed by the tip, most probably due to the disorganization of the matrix layer at acidic pH, fine structural details of ribonucleoproteins (RNP) were obtained. In addition, AFM topography of intact virus in interaction with the supported lipid bilayer confirms that hemeagglutinin and neuraminidase can form isolated clusters within the viral membrane.
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Affiliation(s)
- Cédric Godefroy
- Institut National de la Santé et de la Recherche Médicale, Unité 1054, 34090 Montpellier, France
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23
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The rigid amphipathic fusion inhibitor dUY11 acts through photosensitization of viruses. J Virol 2013; 88:1849-53. [PMID: 24284320 DOI: 10.1128/jvi.02907-13] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Rigid amphipathic fusion inhibitors (RAFIs) are lipophilic inverted-cone-shaped molecules thought to antagonize the membrane curvature transitions that occur during virus-cell fusion and are broad-spectrum antivirals against enveloped viruses (Broad-SAVE). Here, we show that RAFIs act like membrane-binding photosensitizers: their antiviral effect is dependent on light and the generation of singlet oxygen ((1)O(2)), similar to the mechanistic paradigm established for LJ001, a chemically unrelated class of Broad-SAVE. Photosensitization of viral membranes is a common mechanism that underlies these Broad-SAVE.
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24
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Phenothiazines inhibit hepatitis C virus entry, likely by increasing the fluidity of cholesterol-rich membranes. Antimicrob Agents Chemother 2013; 57:2571-81. [PMID: 23529728 DOI: 10.1128/aac.02593-12] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Despite recent progress in the development of direct-acting antiviral agents against hepatitis C virus (HCV), more effective therapies are still urgently needed. We and others previously identified three phenothiazine compounds as potent HCV entry inhibitors. In this study, we show that phenothiazines inhibit HCV entry at the step of virus-host cell fusion, by intercalating into cholesterol-rich domains of the target membrane and increasing membrane fluidity. Perturbation of the alignment/packing of cholesterol in lipid membranes likely increases the energy barrier needed for virus-host fusion. A screening assay based on the ability of molecules to selectively increase the fluidity of cholesterol-rich membranes was subsequently developed. One compound that emerged from the library screen, topotecan, is able to very potently inhibit the fusion of liposomes with cell culture-derived HCV (HCVcc). These results yield new insights into HCV infection and provide a platform for the identification of new HCV inhibitors.
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25
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Pierson TC, Kielian M. Flaviviruses: braking the entering. Curr Opin Virol 2013; 3:3-12. [PMID: 23352692 DOI: 10.1016/j.coviro.2012.12.001] [Citation(s) in RCA: 117] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2012] [Revised: 11/05/2012] [Accepted: 12/05/2012] [Indexed: 12/12/2022]
Abstract
Flaviviruses are small spherical virus particles covered by a dense icosahedral array of envelope (E) proteins that mediate virus attachment to cells and the fusion of viral and cellular membranes. Our understanding of the mechanism by which flavivirus E proteins orchestrate entry into cells has been advanced by studies of E structure and arrangement on the virion at different steps of the virus entry/membrane fusion process. When combined with an increasingly clear (albeit still incomplete) view of the cell biology of virus entry, these advances suggest new antiviral strategies. Indeed, inhibitors that target cellular and viral processes involved in entry show promise as powerful tools to study this critical step of the viral lifecycle, and with luck, may ultimately lead to therapeutic advances.
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Affiliation(s)
- Theodore C Pierson
- Viral Pathogenesis Section, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD 20892, United States.
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5-(Perylen-3-yl)ethynyl-arabino-uridine (aUY11), an arabino-based rigid amphipathic fusion inhibitor, targets virion envelope lipids to inhibit fusion of influenza virus, hepatitis C virus, and other enveloped viruses. J Virol 2013; 87:3640-54. [PMID: 23283943 DOI: 10.1128/jvi.02882-12] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Entry of enveloped viruses requires fusion of viral and cellular membranes. Fusion requires the formation of an intermediate stalk structure, in which only the outer leaflets are fused. The stalk structure, in turn, requires the lipid bilayer of the envelope to bend into negative curvature. This process is inhibited by enrichment in the outer leaflet of lipids with larger polar headgroups, which favor positive curvature. Accordingly, phospholipids with such shape inhibit viral fusion. We previously identified a compound, 5-(perylen-3-yl)ethynyl-2'-deoxy-uridine (dUY11), with overall shape and amphipathicity similar to those of these phospholipids. dUY11 inhibited the formation of the negative curvature necessary for stalk formation and the fusion of a model enveloped virus, vesicular stomatitis virus (VSV). We proposed that dUY11 acted by biophysical mechanisms as a result of its shape and amphipathicity. To test this model, we have now characterized the mechanisms against influenza virus and HCV of 5-(perylen-3-yl)ethynyl-arabino-uridine (aUY11), which has shape and amphipathicity similar to those of dUY11 but contains an arabino-nucleoside. aUY11 interacted with envelope lipids to inhibit the infectivity of influenza virus, hepatitis C virus (HCV), herpes simplex virus 1 and 2 (HSV-1/2), and other enveloped viruses. It specifically inhibited the fusion of influenza virus, HCV, VSV, and even protein-free liposomes to cells. Furthermore, aUY11 inhibited the formation of negative curvature in model lipid bilayers. In summary, the arabino-derived aUY11 and the deoxy-derived dUY11 act by the same antiviral mechanisms against several enveloped but otherwise unrelated viruses. Therefore, chemically unrelated compounds of appropriate shape and amphipathicity target virion envelope lipids to inhibit formation of the negative curvature required for fusion, inhibiting infectivity by biophysical, not biochemical, mechanisms.
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Shin L, Wang S, Lee JS, Flack A, Mao G, Jena BP. Lysophosphatidylcholine inhibits membrane-associated SNARE complex disassembly. J Cell Mol Med 2012; 16:1701-8. [PMID: 21883893 PMCID: PMC3822683 DOI: 10.1111/j.1582-4934.2011.01433.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2011] [Accepted: 08/18/2011] [Indexed: 11/29/2022] Open
Abstract
In cells, N-ethylmaleimide-sensitive factor (NSF) attachment protein receptors called SNAREs are involved in membrane fusion. In neurons, for example, target membrane proteins SNAP-25 and syntaxin called t-SNAREs present at the pre-synaptic membrane, and a synaptic vesicle-associated membrane protein (VAMP) or v-SNARE, is part of the conserved protein complex involved in neurotransmission. Cholesterol and LPC (L-α-lysophosphatidylcholine) are known to contribute to the negative and positive curvature respectively of membranes. In this study, using purified recombinant neuronal membrane-associated SNAREs, we demonstrate for the first time that membrane-curvature-influencing lipids profoundly influence SNARE complex disassembly. Exposure of cholesterol-associated t-SNARE and v-SNARE liposome mixtures to NSF-ATP results in dissociated vesicles. In contrast, exposure of LPC-associated t-SNARE and v-SNARE liposome mixtures to NSF-ATP, results in inhibition of t-/v-SNARE disassembly and the consequent accumulation of clustered vesicles. Similarly, exposure of isolated rat brain slices and pancreas to cholesterol or LPC, also demonstrates LPC-induced inhibition of SNARE complex disassembly. Earlier studies demonstrate a strong correlation between altered plasma LPC levels and cancer. The altered plasma LPC levels observed in various cancers may in part contribute to defects in SNARE assembly-disassembly and membrane fusion, consequently affecting protein maturation and secretion in cancer cells.
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Affiliation(s)
- Leah Shin
- Department of Physiology, Wayne State University School of MedicineDetroit, MI, USA
| | - Sunxi Wang
- Department of Chemical Engineering & Materials Science, College of EngineeringDetroit, MI, USA
| | - Jin-Sook Lee
- Department of Physiology, Wayne State University School of MedicineDetroit, MI, USA
| | - Amanda Flack
- Department of Physiology, Wayne State University School of MedicineDetroit, MI, USA
| | - Guangzhao Mao
- Department of Chemical Engineering & Materials Science, College of EngineeringDetroit, MI, USA
| | - Bhanu P Jena
- Department of Physiology, Wayne State University School of MedicineDetroit, MI, USA
- Department of Chemical Engineering & Materials Science, College of EngineeringDetroit, MI, USA
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Chiou YL, Chen YJ, Lin SR, Chang LS. Phospholipase A2 activity-dependent and -independent fusogenic activity of Naja nigricollis CMS-9 on zwitterionic and anionic phospholipid vesicles. Toxicon 2011; 58:518-26. [DOI: 10.1016/j.toxicon.2011.08.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2011] [Revised: 07/22/2011] [Accepted: 08/23/2011] [Indexed: 10/17/2022]
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29
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Kao PH, Chiou YL, Chen YJ, Lin SR, Chang LS. Guanidination of notexin promotes its phospholipase A(2) activity-independent fusogenicity on vesicles with lipid-supplied negative curvature. Toxicon 2011; 59:47-58. [PMID: 22030836 DOI: 10.1016/j.toxicon.2011.10.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2011] [Revised: 09/27/2011] [Accepted: 10/11/2011] [Indexed: 11/30/2022]
Abstract
To address the requirement of phospholipase A(2) (PLA(2)) activity in membrane fusion events and membrane perturbation activity of notexin and guanidinated notexin (Gu-notexin), the present study was conducted. Notexin and Gu-notexin did not show PLA(2) activity after the removal of Ca(2+) with EDTA. Metal-free notexin and Gu-notexin were found to induce membrane leakage and fusion of phospholipid vesicles. Fusogenic activity of native and modified notexin correlated positively with their membrane-damaging activity underlying the deprivation of PLA(2) activity. Compared with Ca(2+)-bound Gu-notexin, fusogenicity of metal-free Gu-notexin was notably increased by incorporation of cholesterol, cholesterol sulfate, phosphatidylethanolamine, α-tocopherol and phosphatidic acid that supplied negative curvature into phospholipid bilayer. The ability of Gu-notexin to induce membrane fusion of vesicles with lipid-supplied negative curvature was higher than that of notexin regardless of the absence or presence of Ca(2+). Consistently, metal-free Gu-notexin markedly induced membrane fusion of red blood cells (RBCs) compared with metal-free notexin, and fusion activity of metal-free Gu-notexin on cholesterol-depleted RBCs notably reduced. Compared with notexin, Gu-notexin highly induced uptake of calcein-loaded phosphatidylcholine (PC)/cholesterol and PC/cholesterol sulfate vesicles by K562 cells in the presence of EDTA. Taken together, our data suggest that notexin and Gu-notexin could induce vesicle leakage and fusion via a PLA(2) activity-independent mechanism, and guanidination promotes PLA(2) activity-independent fusogenicity of notexin on vesicles with lipid-supplied negative curvature.
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Affiliation(s)
- Pei-Hsiu Kao
- Institute of Biomedical Sciences, National Sun Yat-Sen University, Kaohsiung 804, Taiwan
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30
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Scavenger receptor class B type I and the hypervariable region-1 of hepatitis C virus in cell entry and neutralisation. Expert Rev Mol Med 2011; 13:e13. [PMID: 21489334 DOI: 10.1017/s1462399411001785] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Hepatitis C virus (HCV) infection is a leading cause of chronic liver disease worldwide and represents a major public health problem. Viral attachment and entry - the first encounter of the virus with the host cell - are major targets of neutralising immune responses. Thus, a detailed understanding of the HCV entry process offers interesting opportunities for the development of novel therapeutic strategies. Different cellular or soluble host factors mediate HCV entry, and considerable progress has been made in recent years to decipher how they induce HCV attachment, internalisation and membrane fusion. Among these factors, the scavenger receptor class B type I (SR-BI/SCARB1) is essential for HCV replication in vitro, through its interaction with the HCV E1E2 surface glycoproteins and, more particularly, the HVR1 segment located in the E2 protein. SR-BI is an interesting receptor because HCV, whose replication cycle intersects with lipoprotein metabolism, seems to exploit some aspects of its physiological functions, such as cholesterol transfer from high-density lipoprotein (HDL), during cell entry. SR-BI is also involved in neutralisation attenuation and therefore could be an important target for therapeutic intervention. Recent results suggest that it should be possible to identify inhibitors of the interaction of HCV with SR-BI that do not impair its important physiological properties, as discussed in this review.
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31
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Kaufmann B, Rossmann MG. Molecular mechanisms involved in the early steps of flavivirus cell entry. Microbes Infect 2010; 13:1-9. [PMID: 20869460 DOI: 10.1016/j.micinf.2010.09.005] [Citation(s) in RCA: 94] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2010] [Revised: 08/31/2010] [Accepted: 09/01/2010] [Indexed: 12/31/2022]
Abstract
Flaviviruses enter their host cells by receptor-mediated endocytosis, a well-orchestrated process of receptor recognition, penetration and uncoating. Recent findings on these early steps in the life cycle of flaviviruses are the focus of this review.
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Affiliation(s)
- Bärbel Kaufmann
- Department of Biological Sciences, Purdue University, 915 West State Street, West Lafayette, IN 47907-2054, USA
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32
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Shin L, Cho WJ, Cook JD, Stemmler TL, Jena BP. Membrane lipids influence protein complex assembly-disassembly. J Am Chem Soc 2010; 132:5596-7. [PMID: 20373736 DOI: 10.1021/ja101574d] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Approximately 11% smaller t-/v-SNARE ring complexes are generated using 50 nm cholesterol-associated vesicles as opposed to vesicles containing L-alpha-lysophosphatidylcholine (LPC), as observed using atomic force microscopy. Circular dichroism spectroscopy demonstrated that in the presence of LPC as opposed to cholesterol, N-ethylmaleimide-sensitive factor + adenosine triphosphate induces disassembly of beta-sheet structures but not the alpha-helical contents within the t-/v-SNARE complex.
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Affiliation(s)
- Leah Shin
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan 48201, USA
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33
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Chan RB, Tanner L, Wenk MR. Implications for lipids during replication of enveloped viruses. Chem Phys Lipids 2010; 163:449-59. [PMID: 20230810 PMCID: PMC7124286 DOI: 10.1016/j.chemphyslip.2010.03.002] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2009] [Accepted: 03/08/2010] [Indexed: 01/27/2023]
Abstract
Enveloped viruses, which include many medically important viruses such as human immunodeficiency virus, influenza virus and hepatitis C virus, are intracellular parasites that acquire lipid envelopes from their host cells. Success of replication is intimately linked to their ability to hijack host cell mechanisms, particularly those related to membrane dynamics and lipid metabolism. Despite recent progress, our knowledge of lipid mediated virus-host interactions remains highly incomplete. In addition, diverse experimental systems are used to study different stages of virus replication thus complicating comparisons. This review aims to present a unifying view of the widely diverse strategies used by enveloped viruses at distinct stages of their replication cycles.
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Affiliation(s)
- Robin B Chan
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
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34
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Induction of non-lamellar lipid phases by antimicrobial peptides: a potential link to mode of action. Chem Phys Lipids 2010; 163:82-93. [PMID: 19799887 DOI: 10.1016/j.chemphyslip.2009.09.002] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2009] [Revised: 09/04/2009] [Accepted: 09/23/2009] [Indexed: 12/24/2022]
Abstract
Antimicrobial peptides are naturally produced by numerous organisms including insects, plants and mammals. Their non-specific mode of action is thought to involve the transient perturbation of bacterial membranes but the molecular mechanism underlying the rearrangement of the lipid molecules to explain the formation of pores and micelles is still poorly understood. Biological membranes mostly adopt planar lipid bilayers; however, antimicrobial peptides have been shown to induce non-lamellar lipid phases which may be intimately linked to their proposed mechanisms of action. This paper reviews antimicrobial peptides that alter lipid phase behavior in three ways: peptides that induce positive membrane curvature, peptides that induce negative membrane curvature and peptides that induce cubic lipid phases. Such structures can coexist with the bilayer structure, thus giving rise to lipid polymorphism induced upon addition of antimicrobial peptides. The discussion addresses the implications of induced lipid phases for the mode of action of various antimicrobial peptides.
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35
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Huang CYH, Butrapet S, Moss KJ, Childers T, Erb SM, Calvert AE, Silengo SJ, Kinney RM, Blair CD, Roehrig JT. The dengue virus type 2 envelope protein fusion peptide is essential for membrane fusion. Virology 2009; 396:305-15. [PMID: 19913272 DOI: 10.1016/j.virol.2009.10.027] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2009] [Revised: 09/28/2009] [Accepted: 10/16/2009] [Indexed: 10/20/2022]
Abstract
The flaviviral envelope (E) protein directs virus-mediated membrane fusion. To investigate membrane fusion as a requirement for virus growth, we introduced 27 unique mutations into the fusion peptide of an infectious cDNA clone of dengue 2 virus and recovered seven stable mutant viruses. The fusion efficiency of the mutants was impaired, demonstrating for the first time the requirement for specific FP AAs in optimal fusion. Mutant viruses exhibited different growth kinetics and/or genetic stabilities in different cell types and adult mosquitoes. Virus particles could be recovered following RNA transfection of cells with four lethal mutants; however, recovered viruses could not re-infect cells. These viruses could enter cells, but internalized virus appeared to be retained in endosomal compartments of infected cells, thus suggesting a fusion blockade. Mutations of the FP also resulted in reduced virus reactivity with flavivirus group-reactive antibodies, confirming earlier reports using virus-like particles.
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Affiliation(s)
- Claire Y-H Huang
- Division of Vector-Borne Infectious Diseases, Centers for Disease Control and Prevention, Public Health Service, U.S. Department of Health and Human Services, 3150 Rampart Rd., Fort Collins, CO 80521, USA.
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36
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Schibli DJ, Weissenhorn W. Class I and class II viral fusion protein structures reveal similar principles in membrane fusion (Review). Mol Membr Biol 2009; 21:361-71. [PMID: 15764366 DOI: 10.1080/09687860400017784] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Recent crystal structures of Flavivirus and Alphavirus fusion proteins (class II) confirm two major principles of protein machineries that mediate the merger of two opposing lipid bilayers. First, the fusion protein can bridge both membranes tethered by two membrane anchors. Second, refolding or domain rearrangement steps lead to the positioning of both anchors into close proximity at the same end of an elongated structure. Although these two steps are in principle sufficient to pull two opposing membranes together and initiate membrane fusion, accumulating evidence suggests that the process requires the concerted action of a number of fusion proteins at and outside the contact sites. This review will focus on the structures of viral class I and class II fusion proteins and their similarities in facilitating membrane fusion.
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37
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Human monoclonal antibodies against West Nile virus induced by natural infection neutralize at a postattachment step. J Virol 2009; 83:6494-507. [PMID: 19386704 DOI: 10.1128/jvi.00286-09] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
West Nile virus (WNV) is a neurotropic flavivirus that is now a primary cause of epidemic encephalitis in North America. Studies of mice have demonstrated that the humoral immune response against WNV limits primary infection and protects against a secondary challenge. The most-potent neutralizing mouse monoclonal antibodies (MAbs) recognize an epitope on the lateral ridge of domain III (DIII-lr) of the envelope (E) protein. However, studies with serum from human patients show that antibodies against the DIII-lr epitope comprise, at best, a minor component of the human anti-WNV antibody response. Herein, we characterize in detail two WNV-specific human MAbs, CR4348 and CR4354, that were isolated from B-cell populations of convalescent patients. These MAbs strongly neutralize WNV infection of cultured cells, protect mice against lethal infection in vivo, and yet poorly recognize recombinant forms of the E protein. Instead, CR4348 and CR4354 bind determinants on intact WNV virions and subviral particles in a pH-sensitive manner, and neutralization is altered by mutations at the dimer interface in domain II and the hinge between domains I and II, respectively. CR4348 and CR4354 human MAbs neutralize infection at a postattachment step in the viral life cycle, likely by inhibiting acid-induced fusion within the endosome.
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38
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Dreux M, Dao Thi VL, Fresquet J, Guérin M, Julia Z, Verney G, Durantel D, Zoulim F, Lavillette D, Cosset FL, Bartosch B. Receptor complementation and mutagenesis reveal SR-BI as an essential HCV entry factor and functionally imply its intra- and extra-cellular domains. PLoS Pathog 2009; 5:e1000310. [PMID: 19229312 PMCID: PMC2636890 DOI: 10.1371/journal.ppat.1000310] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2008] [Accepted: 01/23/2009] [Indexed: 12/11/2022] Open
Abstract
HCV entry into cells is a multi-step and slow process. It is believed that the
initial capture of HCV particles by glycosaminoglycans and/or lipoprotein
receptors is followed by coordinated interactions with the scavenger receptor
class B type I (SR-BI), a major receptor of high-density lipoprotein (HDL), the
CD81 tetraspanin, and the tight junction protein Claudin-1, ultimately leading
to uptake and cellular penetration of HCV via low-pH endosomes.
Several reports have indicated that HDL promotes HCV entry through interaction
with SR-BI. This pathway remains largely elusive, although it was shown that HDL
neither associates with HCV particles nor modulates HCV binding to SR-BI. In
contrast to CD81 and Claudin-1, the importance of SR-BI has only been addressed
indirectly because of lack of cells in which functional complementation assays
with mutant receptors could be performed. Here we identified for the first time
two cell types that supported HCVpp and HCVcc entry upon ectopic SR-BI
expression. Remarkably, the undetectable expression of SR-BI in rat hepatoma
cells allowed unambiguous investigation of human SR-BI functions during HCV
entry. By expressing different SR-BI mutants in either cell line, our results
revealed features of SR-BI intracellular domains that influence HCV infectivity
without affecting receptor binding and stimulation of HCV entry induced by
HDL/SR-BI interaction. Conversely, we identified positions of SR-BI ectodomain
that, by altering HCV binding, inhibit entry. Finally, we characterized
alternative ectodomain determinants that, by reducing SR-BI cholesterol uptake
and efflux functions, abolish HDL-mediated infection-enhancement. Altogether, we
demonstrate that SR-BI is an essential HCV entry factor. Moreover, our results
highlight specific SR-BI determinants required during HCV entry and
physiological lipid transfer functions hijacked by HCV to favor infection. More than 180 million people are chronically infected by hepatitis C virus (HCV),
a leading cause of liver failure and cancer, stimulating the need to fully
define the biology of HCV infection for developing novel and effective
therapeutics. During the first steps of infection, the virus is taken up and
penetrates hepatocytes. HCV entry is thought to be a coordinated multi-step
process mediated by specific factors, including CD81, Claudin-1, and the
scavenger receptor BI (SR-BI). Whereas the involvement of CD81 and Claudin-1 was
demonstrated by rendering susceptible cells that are otherwise refractory, SR-BI
complementation assays were lacking, raising questions as to its functions
during HCV entry. Here, we identify one hepatoma rat cell line, in which SR-BI
complementation assay and targeted mutagenesis could be performed. We therefore
demonstrate that SR-BI is an essential HCV entry factor. Our results shed light
on SR-BI intracellular domain functions in HCV entry, and, further, emphasize
the remarkable capacity of HCV to hijack the lipid transfer function of SR-BI,
hence favoring infection.
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Affiliation(s)
- Marlène Dreux
- Université de Lyon, UCB-Lyon1, IFR128; INSERM, U758; Ecole
Normale Supérieure de Lyon, Lyon, France
| | - Viet Loan Dao Thi
- Université de Lyon, UCB-Lyon1, IFR128; INSERM, U758; Ecole
Normale Supérieure de Lyon, Lyon, France
| | - Judith Fresquet
- Université de Lyon, UCB-Lyon1, IFR128; INSERM, U758; Ecole
Normale Supérieure de Lyon, Lyon, France
| | | | | | - Géraldine Verney
- Université de Lyon, UCB-Lyon1, IFR128; INSERM, U758; Ecole
Normale Supérieure de Lyon, Lyon, France
| | - David Durantel
- Université de Lyon, UCB-Lyon1, IFR62; INSERM, U871; Hospices
civils de Lyon (HCL), Lyon, France
| | - Fabien Zoulim
- Université de Lyon, UCB-Lyon1, IFR62; INSERM, U871; Hospices
civils de Lyon (HCL), Lyon, France
| | - Dimitri Lavillette
- Université de Lyon, UCB-Lyon1, IFR128; INSERM, U758; Ecole
Normale Supérieure de Lyon, Lyon, France
| | - François-Loïc Cosset
- Université de Lyon, UCB-Lyon1, IFR128; INSERM, U758; Ecole
Normale Supérieure de Lyon, Lyon, France
- * E-mail:
| | - Birke Bartosch
- Université de Lyon, UCB-Lyon1, IFR128; INSERM, U758; Ecole
Normale Supérieure de Lyon, Lyon, France
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Melikyan GB. Common principles and intermediates of viral protein-mediated fusion: the HIV-1 paradigm. Retrovirology 2008; 5:111. [PMID: 19077194 PMCID: PMC2633019 DOI: 10.1186/1742-4690-5-111] [Citation(s) in RCA: 135] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2008] [Accepted: 12/10/2008] [Indexed: 12/20/2022] Open
Abstract
Enveloped viruses encode specialized fusion proteins which promote the merger of viral and cell membranes, permitting the cytosolic release of the viral cores. Understanding the molecular details of this process is essential for antiviral strategies. Recent structural studies revealed a stunning diversity of viral fusion proteins in their native state. In spite of this diversity, the post-fusion structures of these proteins share a common trimeric hairpin motif in which the amino- and carboxy-terminal hydrophobic domains are positioned at the same end of a rod-shaped molecule. The converging hairpin motif, along with biochemical and functional data, implies that disparate viral proteins promote membrane merger via a universal "cast-and-fold" mechanism. According to this model, fusion proteins first anchor themselves to the target membrane through their hydrophobic segments and then fold back, bringing the viral and cellular membranes together and forcing their merger. However, the pathways of protein refolding and the mechanism by which this refolding is coupled to membrane rearrangements are still not understood. The availability of specific inhibitors targeting distinct steps of HIV-1 entry permitted the identification of key conformational states of its envelope glycoprotein en route to fusion. These studies provided functional evidence for the direct engagement of the target membrane by HIV-1 envelope glycoprotein prior to fusion and revealed the role of partially folded pre-hairpin conformations in promoting the pore formation.
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Affiliation(s)
- Gregory B Melikyan
- Institute of Human Virology, Department of Microbiology and Immunology, University of Maryland School of Medicine, 725 W, Lombard St, Baltimore, MD 21201, USA.
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40
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Interaction of the most membranotropic region of the HCV E2 envelope glycoprotein with membranes. Biophysical characterization. Biophys J 2008; 94:4737-50. [PMID: 18339752 DOI: 10.1529/biophysj.107.126896] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The previously identified membrane-active regions of the hepatitis C virus (HCV) E1 and E2 envelope glycoproteins led us to identify different segments that might be implicated in viral membrane fusion, membrane interaction, and/or protein-protein binding. HCV E2 glycoprotein contains one of the most membranotropic segments, segment 603-634, which has been implicated in CD81 binding, E1/E2 and E2/E2 dimerization, and membrane interaction. Through a series of complementary experiments, we have carried out a study of the binding and interaction with the lipid bilayer of a peptide corresponding to segment 603-634, peptide E2(FP), as well as the structural changes induced by membrane binding that take place in both the peptide and the phospholipid molecules. Here, we demonstrate that peptide E2(FP) binds to and interacts with phospholipid model membranes, modulates the polymorphic phase behavior of membrane phospholipids, is localized in a shallow position in the membrane, and is probably oligomerized in the presence of membranes. These data support the role of E2(FP) in HCV-mediated membrane fusion, and sustain the notion that this segment of the E2 envelope glycoprotein, together with other segments of E2 and E1 glycoproteins, provides the driving force for the merging of the viral and target cell membranes.
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41
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Teissier É, Pécheur EI. Lipids as modulators of membrane fusion mediated by viral fusion proteins. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2007; 36:887-99. [PMID: 17882414 PMCID: PMC7080115 DOI: 10.1007/s00249-007-0201-z] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/15/2007] [Revised: 05/17/2007] [Accepted: 06/11/2007] [Indexed: 11/24/2022]
Abstract
Enveloped viruses infect host cells by fusion of viral and target membranes. This fusion event is triggered by specific glycoproteins in the viral envelope. Fusion glycoproteins belong to either class I, class II or the newly described third class, depending upon their arrangement at the surface of the virion, their tri-dimensional structure and the location within the protein of a short stretch of hydrophobic amino acids called the fusion peptide, which is able to induce the initial lipid destabilization at the onset of fusion. Viral fusion occurs either with the plasma membrane for pH-independent viruses, or with the endosomal membranes for pH-dependent viruses. Although, viral fusion proteins are parted in three classes and the subcellular localization of fusion might vary, these proteins have to act, in common, on lipid assemblies. Lipids contribute to fusion through their physical, mechanical and/or chemical properties. Lipids can thus play a role as chemically defined entities, or through their preferential partitioning into membrane microdomains called “rafts”, or by modulating the curvature of the membranes involved in the fusion process. The purpose of this review is to make a state of the art on recent findings on the contribution of cholesterol, sphingolipids and glycolipids in cell entry and membrane fusion of a number of viral families, whose members bear either class I or class II fusion proteins, or fusion proteins of the recently discovered third class.
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Affiliation(s)
- Élodie Teissier
- Structural NMR and Bioinformatics, UMR CNRS 5086, Institut de Biologie et Chimie des Protéines, IFR 128 BioSciences Lyon-Gerland, 7 passage du Vercors, 69367 Lyon, France
| | - Eve-Isabelle Pécheur
- Structural NMR and Bioinformatics, UMR CNRS 5086, Institut de Biologie et Chimie des Protéines, IFR 128 BioSciences Lyon-Gerland, 7 passage du Vercors, 69367 Lyon, France
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Amatore C, Arbault S, Bouret Y, Guille M, Lemaître F, Verchier Y. Regulation of exocytosis in chromaffin cells by trans-insertion of lysophosphatidylcholine and arachidonic acid into the outer leaflet of the cell membrane. Chembiochem 2007; 7:1998-2003. [PMID: 17086558 DOI: 10.1002/cbic.200600194] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Vesicular exocytosis is an important complex process in the communication between cells in organisms. It controls the release of chemical and biochemical messengers stored in an emitting cell. In this report, exocytosis is studied amperometrically (at carbon fiber ultramicroelectrodes) at adrenal chromaffin cells, which release catecholamines after appropriate stimulation, while testing the effects due to trans-insertion of two exogenous compounds (lysophosphatidylcholine (LPC) and arachidonic acid (AA)) on the kinetics of exocytotic events. Amperometric analyses showed that, under the present conditions (short incubation times and micromolar LPC or AA solutions), LPC favors catecholamine release (rate, event frequency, charge released) while AA disfavors the exocytotic processes. The observed kinetic features are rationalized quantitatively by considering a stalk model, for the fusion pore formation, and the physical constraints applied to the cell membrane by the presence of small fractions of LPC and AA diluted in its external leaflet (trans-insertion). We also observed that the detected amount of neurotransmitters in the presence of LPC was larger than under control conditions, while the opposite trend is observed with AA.
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Affiliation(s)
- Christian Amatore
- Ecole Normale Supérieure, Département de Chimie, UMR CNRS-ENS-UPMC 8640 PASTEUR, 24 rue Lhomond, 75231 Paris Cedex 05, France.
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Abstract
Flavivirus membrane fusion is mediated by a class II viral fusion protein, the major envelope protein E, and the fusion process is extremely fast and efficient. Understanding of the underlying mechanisms has been advanced significantly by the determination of E protein structures in their pre- and post-fusion conformations and by the elucidation of the quarternary organization of E proteins in the viral envelope. In this review, these structural data are discussed in the context of functional and biochemical analyses of the flavivirus fusion mechanism and its characteristics are compared with those of other class II- and class I-driven fusion processes.
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Affiliation(s)
- Karin Stiasny
- Institute of Virology, Medical University of Vienna, Kinderspitalgasse 15, A1095 Vienna, Austria
| | - Franz X Heinz
- Institute of Virology, Medical University of Vienna, Kinderspitalgasse 15, A1095 Vienna, Austria
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Nybakken GE, Nelson CA, Chen BR, Diamond MS, Fremont DH. Crystal structure of the West Nile virus envelope glycoprotein. J Virol 2006; 80:11467-74. [PMID: 16987985 PMCID: PMC1642602 DOI: 10.1128/jvi.01125-06] [Citation(s) in RCA: 202] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The envelope glycoprotein (E) of West Nile virus (WNV) undergoes a conformational rearrangement triggered by low pH that results in a class II fusion event required for viral entry. Herein we present the 3.0-A crystal structure of the ectodomain of WNV E, which reveals insights into the flavivirus life cycle. We found that WNV E adopts a three-domain architecture that is shared by the E proteins from dengue and tick-borne encephalitis viruses and forms a rod-shaped configuration similar to that observed in immature flavivirus particles. Interestingly, the single N-linked glycosylation site on WNV E is displaced by a novel alpha-helix, which could potentially alter lectin-mediated attachment. The localization of histidines within the hinge regions of E implicates these residues in pH-induced conformational transitions. Most strikingly, the WNV E ectodomain crystallized as a monomer, in contrast to other flavivirus E proteins, which have crystallized as antiparallel dimers. WNV E assembles in a crystalline lattice of perpendicular molecules, with the fusion loop of one E protein buried in a hydrophobic pocket at the DI-DIII interface of another. Dimeric E proteins pack their fusion loops into analogous pockets at the dimer interface. We speculate that E proteins could pivot around the fusion loop-pocket junction, allowing virion conformational transitions while minimizing fusion loop exposure.
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Affiliation(s)
- Grant E Nybakken
- Department of Pathology & Immunology, Washington University School of Medicine, Campus Box 8118, 660 South Euclid Avenue, St. Louis, MO 63110-1093, USA
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Lavillette D, Bartosch B, Nourrisson D, Verney G, Cosset FL, Penin F, Pécheur EI. Hepatitis C virus glycoproteins mediate low pH-dependent membrane fusion with liposomes. J Biol Chem 2005; 281:3909-17. [PMID: 16356932 DOI: 10.1074/jbc.m509747200] [Citation(s) in RCA: 111] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
It has been suggested that the hepatitis C virus (HCV) infects host cells through a pH-dependent internalization mechanism, but the steps leading from virus attachment to the fusion of viral and cellular membranes remain uncharacterized. Here we studied the mechanism underlying the HCV fusion process in vitro using liposomes and our recently described HCV pseudoparticles (pp) bearing functional E1E2 envelope glycoproteins. The fusion of HCVpp with liposomes was monitored with fluorescent probes incorporated into either the HCVpp or the liposomes. To validate these assays, pseudoparticles bearing either the hemagglutinin of the influenza virus or the amphotropic glycoprotein of murine leukemia virus were used as models for pH-dependent and pH-independent entry, respectively. The use of assays based either on fusion-induced dequenching of fluorescent probes or on reporter systems, which produce fluorescence when the virus and liposome contents are mixed, allowed us to demonstrate that HCVpp mediated a complete fusion process, leading to the merging of both membrane leaflets and to the mixing of the internal contents of pseudoparticle and liposome. This HCVpp-mediated fusion was dependent on low pH, with a threshold of 6.3 and an optimum at about 5.5. Fusion was temperature-dependent and did not require any protein or receptor at the surface of the target liposomes. Most interestingly, fusion was facilitated by the presence of cholesterol in the target membrane. These findings clearly indicate that HCV infection is mediated by a pH-dependent membrane fusion process. This paves the way for future studies of the mechanisms underlying HCV membrane fusion.
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Affiliation(s)
- Dimitri Lavillette
- IFR128 Biosciences Lyon Gerland, Institut de Biologie et Chimie des Protéines, UMR 5086 CNRS-Université Claude Bernard de Lyon
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Bailey A, Zhukovsky M, Gliozzi A, Chernomordik LV. Liposome composition effects on lipid mixing between cells expressing influenza virus hemagglutinin and bound liposomes. Arch Biochem Biophys 2005; 439:211-21. [PMID: 15963452 DOI: 10.1016/j.abb.2005.05.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2005] [Revised: 05/03/2005] [Accepted: 05/05/2005] [Indexed: 11/23/2022]
Abstract
The involvement of contacting and distal lipid monolayers in different stages of protein-mediated fusion was studied for fusion mediated by influenza virus hemagglutinin. Inclusion of non-bilayer lipids in the composition of the liposomes bound to hemagglutinin-expressing cells affects fusion triggered by low pH. Lysophosphatidylcholine added to the outer membrane monolayers inhibits fusion. The same lipid added to the inner monolayer of the liposomes promotes both lipid and content mixing. In contrast to the inverted cone-shaped lysophosphatidylcholine, lipids of the opposite effective shape, oleic acid or cardiolipin with calcium, present in the inner monolayers inhibit fusion. These results along with fusion inhibition by a bipolar lipid that does not support peeling of one monolayer of the liposomal membrane from the other substantiate the hypothesis that fusion proceeds through a local hemifusion intermediate. The transition from hemifusion to the opening of an expanding fusion pore allows content mixing and greatly facilitates lipid mixing between liposomes and cells.
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Affiliation(s)
- Austin Bailey
- Section on Membrane Biology, Laboratory of Cellular and Molecular Biophysics, NICHD, NIH, Bethesda, MD, USA
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Zaitseva E, Mittal A, Griffin DE, Chernomordik LV. Class II fusion protein of alphaviruses drives membrane fusion through the same pathway as class I proteins. ACTA ACUST UNITED AC 2005; 169:167-77. [PMID: 15809312 PMCID: PMC2171914 DOI: 10.1083/jcb.200412059] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
Viral fusion proteins of classes I and II differ radically in their initial structures but refold toward similar conformations upon activation. Do fusion pathways mediated by alphavirus E1 and influenza virus hemagglutinin (HA) that exemplify classes II and I differ to reflect the difference in their initial conformations, or concur to reflect the similarity in the final conformations? Here, we dissected the pathway of low pH–triggered E1-mediated cell–cell fusion by reducing the numbers of activated E1 proteins and by blocking different fusion stages with specific inhibitors. The discovered progression from transient hemifusion to small, and then expanding, fusion pores upon an increase in the number of activated fusion proteins parallels that established for HA-mediated fusion. We conclude that proteins as different as E1 and HA drive fusion through strikingly similar membrane intermediates, with the most energy-intensive stages following rather than preceding hemifusion. We propose that fusion reactions catalyzed by all proteins of both classes follow a similar pathway.
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Affiliation(s)
- Elena Zaitseva
- Section on Membrane Biology, Laboratory of Cellular and Molecular Biophysics, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
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