1
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Wang C, Xia S, Wang X, Li Y, Wang H, Xiang R, Jiang Q, Lan Q, Liang R, Li Q, Huo S, Lu L, Wang Q, Yu F, Liu K, Jiang S. Supercoiling Structure-Based Design of a Trimeric Coiled-Coil Peptide with High Potency against HIV-1 and Human β-Coronavirus Infection. J Med Chem 2022; 65:2809-2819. [PMID: 33929200 PMCID: PMC8117781 DOI: 10.1021/acs.jmedchem.1c00258] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Indexed: 12/15/2022]
Abstract
Hexameric structure formation through packing of three C-terminal helices and an N-terminal trimeric coiled-coil core has been proposed as a general mechanism of class I enveloped virus entry. In this process, the C-terminal helical repeat (HR2) region of viral membrane fusion proteins becomes transiently exposed and accessible to N-terminal helical repeat (HR1) trimer-based fusion inhibitors. Herein, we describe a mimetic of the HIV-1 gp41 HR1 trimer, N3G, as a promising therapeutic against HIV-1 infection. Surprisingly, we found that in addition to protection against HIV-1 infection, N3G was also highly effective in inhibiting infection of human β-coronaviruses, including MERS-CoV, HCoV-OC43, and SARS-CoV-2, possibly by binding the HR2 region in the spike protein of β-coronaviruses to block their hexameric structure formation. These studies demonstrate the potential utility of anti-HIV-1 HR1 peptides in inhibiting human β-coronavirus infection. Moreover, this strategy could be extended to the design of broad-spectrum antivirals based on the supercoiling structure of peptides.
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Affiliation(s)
- Chao Wang
- State Key Laboratory of Toxicology and Medical
Countermeasures, Beijing Institute of Pharmacology and
Toxicology, 27 Tai-Ping Road, Beijing 100850,
China
| | - Shuai Xia
- Key Laboratory of Medical Molecular Virology
(MOE/NHC/CAMS), School of Basic Medical Sciences & Shanghai Public Health Clinical
Center, Fudan University, 130 Dong An Road, Shanghai 200032,
China
| | - Xinling Wang
- Key Laboratory of Medical Molecular Virology
(MOE/NHC/CAMS), School of Basic Medical Sciences & Shanghai Public Health Clinical
Center, Fudan University, 130 Dong An Road, Shanghai 200032,
China
| | - Yue Li
- State Key Laboratory of Toxicology and Medical
Countermeasures, Beijing Institute of Pharmacology and
Toxicology, 27 Tai-Ping Road, Beijing 100850,
China
| | - Huan Wang
- State Key Laboratory of Toxicology and Medical
Countermeasures, Beijing Institute of Pharmacology and
Toxicology, 27 Tai-Ping Road, Beijing 100850,
China
| | - Rong Xiang
- Hebei Center for Wildlife Health, College of Life
Sciences, Hebei Agricultural University, Baoding 071001,
China
| | - Qinwen Jiang
- Key Laboratory of Structure-based Drug Design &
Discovery of the Ministry of Education, Shenyang Pharmaceutical
University, Shenyang 110016, China
| | - Qiaoshuai Lan
- Key Laboratory of Medical Molecular Virology
(MOE/NHC/CAMS), School of Basic Medical Sciences & Shanghai Public Health Clinical
Center, Fudan University, 130 Dong An Road, Shanghai 200032,
China
| | - Ruiying Liang
- Hebei Center for Wildlife Health, College of Life
Sciences, Hebei Agricultural University, Baoding 071001,
China
| | - Qing Li
- State Key Laboratory of Toxicology and Medical
Countermeasures, Beijing Institute of Pharmacology and
Toxicology, 27 Tai-Ping Road, Beijing 100850,
China
| | - Shanshan Huo
- Hebei Center for Wildlife Health, College of Life
Sciences, Hebei Agricultural University, Baoding 071001,
China
| | - Lu Lu
- Key Laboratory of Medical Molecular Virology
(MOE/NHC/CAMS), School of Basic Medical Sciences & Shanghai Public Health Clinical
Center, Fudan University, 130 Dong An Road, Shanghai 200032,
China
| | - Qian Wang
- Key Laboratory of Medical Molecular Virology
(MOE/NHC/CAMS), School of Basic Medical Sciences & Shanghai Public Health Clinical
Center, Fudan University, 130 Dong An Road, Shanghai 200032,
China
| | - Fei Yu
- Hebei Center for Wildlife Health, College of Life
Sciences, Hebei Agricultural University, Baoding 071001,
China
| | - Keliang Liu
- State Key Laboratory of Toxicology and Medical
Countermeasures, Beijing Institute of Pharmacology and
Toxicology, 27 Tai-Ping Road, Beijing 100850,
China
| | - Shibo Jiang
- Key Laboratory of Medical Molecular Virology
(MOE/NHC/CAMS), School of Basic Medical Sciences & Shanghai Public Health Clinical
Center, Fudan University, 130 Dong An Road, Shanghai 200032,
China
- Lindsley F. Kimball Research Institute,
New York Blood Center, New York, New York 10065,
United States
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2
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Yu D, Zhu Y, Yan H, Wu T, Chong H, He Y. Pan-coronavirus fusion inhibitors possess potent inhibitory activity against HIV-1, HIV-2, and simian immunodeficiency virus. Emerg Microbes Infect 2021; 10:810-821. [PMID: 33847245 PMCID: PMC8812798 DOI: 10.1080/22221751.2021.1917309] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
EK1 peptide is a membrane fusion inhibitor with broad-spectrum activity against human coronaviruses (CoVs). In the outbreak of COVID-19, we generated a lipopeptide EK1V1 by modifying EK1 with cholesterol, which exhibited significantly improved antiviral activity. In this study, we surprisingly found that EK1V1 also displayed potent cross-inhibitory activities against divergent HIV-1, HIV-2, and simian immunodeficiency virus (SIV) isolates. Consistently, the recently reported EK1 derivative EK1C4 and SARS-CoV-2 derived fusion inhibitor lipopeptides (IPB02 ∼ IPB09) also inhibited HIV-1 Env-mediated cell-cell fusion and infection efficiently. In the inhibition of a panel of HIV-1 mutants resistant to HIV-1 fusion inhibitors, EK1V1 and IPB02-based inhibitors exhibited significantly decreased or increased activities, suggesting the heptad repeat-1 region (HR1) of HIV-1 gp41 being their target. Furthermore, the sequence alignment and molecular docking analyses verified the target site and revealed the mechanism underlying the resistance. Combined, we conclude that this serendipitous discovery provides a proof-of-concept for a common mechanism of viral fusion and critical information for the development of broad-spectrum antivirals.
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Affiliation(s)
- Danwei Yu
- NHC Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology and Center for AIDS Research, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, People's Republic of China
| | - Yuanmei Zhu
- NHC Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology and Center for AIDS Research, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, People's Republic of China
| | - Hongxia Yan
- NHC Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology and Center for AIDS Research, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, People's Republic of China
| | - Tong Wu
- NHC Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology and Center for AIDS Research, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, People's Republic of China
| | - Huihui Chong
- NHC Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology and Center for AIDS Research, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, People's Republic of China
| | - Yuxian He
- NHC Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology and Center for AIDS Research, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, People's Republic of China
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3
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Ahmadi K, Farasat A, Rostamian M, Johari B, Madanchi H. Enfuvirtide, an HIV-1 fusion inhibitor peptide, can act as a potent SARS-CoV-2 fusion inhibitor: an in silico drug repurposing study. J Biomol Struct Dyn 2021; 40:5566-5576. [PMID: 33438525 PMCID: PMC7814568 DOI: 10.1080/07391102.2021.1871958] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Regarding the urgency of therapeutic measures for coronavirus disease 2019 (COVID-19) pandemic, the use of available drugs with FDA approval is preferred because of the less time and cost required for their development. In silico drug repurposing is an accurate way to speed up the screening of the existing FDA-approved drugs to find a therapeutic option for COVID-19. The similarity in SARS-CoV-2 and HIV-1 fusion mechanism to host cells can be a key point for Inhibit SARS-CoV-2 entry into host cells by HIV fusion inhibitors. Accordingly, in this study, an HIV-1 fusion inhibitor called Enfuvirtide (Enf) was selected. The affinity and essential residues involving in the Enf binding to the S2 protein of SARS-CoV-2, HIV-1 gp41 protein and angiotensin-converting enzyme 2 (ACE-2) as a negative control, was evaluated using molecular docking. Eventually, Enf-S2 and Enf-gp41 protein complexes were simulated by molecular dynamics (MD) in terms of binding affinity and stability. Based on the most important criteria such as docking score, cluster size, energy and dissociation constant, the strongest interaction was observed between Enf with the S2 protein. In addition, MD results confirmed that Enf-S2 protein interaction was remarkably stable and caused the S2 protein residues to undergo the fewest fluctuations. In conclusion, it can be stated that Enf can act as a strong SARS-CoV-2 fusion inhibitor and demonstrates the potential to enter the clinical trial phase of COVID-19. Communicated by Ramaswamy H. Sarma
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Affiliation(s)
- Khadijeh Ahmadi
- Infectious and Tropical Diseases Research Center, Hormozgan Health Institute, Hormozgan University of Medical Sciences, Bandar Abbas, Iran
| | - Alireza Farasat
- Cellular and Molecular Research Center, Research Institute for Prevention of Non Communicable Diseases, Qazvin University of Medical Sciences, Qazvin, Iran.,Medical Microbiology Research Center, Qazvin University of Medical Sciences, Qazvin, Iran
| | - Mosayeb Rostamian
- Infectious Diseases Research Center, Health Institute, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - Behrooz Johari
- Department of Medical Biotechnology, School of Medicine, Zanjan University of Medical Sciences, Zanjan, Iran
| | - Hamid Madanchi
- Department of Biotechnology, School of Medicine, Semnan University of Medical Sciences, Semnan, Iran.,Drug Design and Bioinformatics Unit, Department of Medical Biotechnology, Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran
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4
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Mathieu C, Augusto MT, Niewiesk S, Horvat B, Palermo LM, Sanna G, Madeddu S, Huey D, Castanho MARB, Porotto M, Santos NC, Moscona A. Broad spectrum antiviral activity for paramyxoviruses is modulated by biophysical properties of fusion inhibitory peptides. Sci Rep 2017; 7:43610. [PMID: 28344321 PMCID: PMC5361215 DOI: 10.1038/srep43610] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Accepted: 01/30/2017] [Indexed: 01/08/2023] Open
Abstract
Human paramyxoviruses include global causes of lower respiratory disease like the parainfluenza viruses, as well as agents of lethal encephalitis like Nipah virus. Infection is initiated by viral glycoprotein-mediated fusion between viral and host cell membranes. Paramyxovirus viral fusion proteins (F) insert into the target cell membrane, and form a transient intermediate that pulls the viral and cell membranes together as two heptad-repeat regions refold to form a six-helix bundle structure that can be specifically targeted by fusion-inhibitory peptides. Antiviral potency can be improved by sequence modification and lipid conjugation, and by adding linkers between the protein and lipid components. We exploit the uniquely broad spectrum antiviral activity of a parainfluenza F-derived peptide sequence that inhibits both parainfluenza and Nipah viruses, to investigate the influence of peptide orientation and intervening linker length on the peptides' interaction with transitional states of F, solubility, membrane insertion kinetics, and protease sensitivity. We assessed the impact of these features on biodistribution and antiviral efficacy in vitro and in vivo. The engineering approach based on biophysical parameters resulted in a peptide that is a highly effective inhibitor of both paramyxoviruses and a set of criteria to be used for engineering broad spectrum antivirals for emerging paramyxoviruses.
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Affiliation(s)
- Cyrille Mathieu
- CIRI, International Center for Infectiology Research, 21 Avenue Tony Garnier, 69365 Lyon Cedex 07, France.,INSERM U1111, Lyon, France.,CNRS, UMR5308, Lyon, France.,Université Lyon 1, Lyon, France.,Ecole Normale Supérieure de Lyon, Lyon, France
| | - Marcelo T Augusto
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Av. Prof. Egas Moniz, 1649-028 Lisbon, Portugal
| | - Stefan Niewiesk
- Department of Veterinary Biosciences, College of Veterinary Medicine, Ohio State University, Columbus, USA
| | - Branka Horvat
- CIRI, International Center for Infectiology Research, 21 Avenue Tony Garnier, 69365 Lyon Cedex 07, France.,INSERM U1111, Lyon, France.,CNRS, UMR5308, Lyon, France.,Université Lyon 1, Lyon, France.,Ecole Normale Supérieure de Lyon, Lyon, France
| | - Laura M Palermo
- Department of Pediatrics, Columbia University Medical Center, 701 W. 168th St., New York, NY, USA.,Center for Host-Pathogen Interaction, Columbia University Medical Center, 701 W. 168th St., New York, NY, USA
| | - Giuseppina Sanna
- Department of Pediatrics, Columbia University Medical Center, 701 W. 168th St., New York, NY, USA.,Center for Host-Pathogen Interaction, Columbia University Medical Center, 701 W. 168th St., New York, NY, USA.,Department of Biomedical Sciences, University of Cagliari, Cittadella Universitaria, Monserrato, Cagliari, Italy
| | - Silvia Madeddu
- Department of Pediatrics, Columbia University Medical Center, 701 W. 168th St., New York, NY, USA.,Center for Host-Pathogen Interaction, Columbia University Medical Center, 701 W. 168th St., New York, NY, USA.,Department of Biomedical Sciences, University of Cagliari, Cittadella Universitaria, Monserrato, Cagliari, Italy
| | - Devra Huey
- Department of Veterinary Biosciences, College of Veterinary Medicine, Ohio State University, Columbus, USA
| | - Miguel A R B Castanho
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Av. Prof. Egas Moniz, 1649-028 Lisbon, Portugal
| | - Matteo Porotto
- Department of Pediatrics, Columbia University Medical Center, 701 W. 168th St., New York, NY, USA.,Center for Host-Pathogen Interaction, Columbia University Medical Center, 701 W. 168th St., New York, NY, USA
| | - Nuno C Santos
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Av. Prof. Egas Moniz, 1649-028 Lisbon, Portugal
| | - Anne Moscona
- Department of Pediatrics, Columbia University Medical Center, 701 W. 168th St., New York, NY, USA.,Center for Host-Pathogen Interaction, Columbia University Medical Center, 701 W. 168th St., New York, NY, USA.,Department of Microbiology &Immunology, Columbia University Medical Center, 701 W. 168th St., New York, NY, USA.,Department of Physiology &Biophysics, Columbia University Medical Center, 701 W. 168th St., New York, NY, USA
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5
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Freire JM, Veiga AS, de la Torre BG, Andreu D, Castanho MARB. Quantifying molecular partition of cell-penetrating peptide-cargo supramolecular complexes into lipid membranes: optimizing peptide-based drug delivery systems. J Pept Sci 2013; 19:182-9. [PMID: 23322613 DOI: 10.1002/psc.2477] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2012] [Revised: 11/23/2012] [Accepted: 11/26/2012] [Indexed: 11/08/2022]
Abstract
One of the major challenges in the drug development process is biodistribution across epithelia and intracellular drug targeting. Cellular membrane heterogeneity is one of the major drawbacks in developing efficient and sustainable drug delivery systems, which brings the need to study their interaction with lipids in order to unravel their mechanisms of action and improve their delivery capacities. Cell penetrating peptides (CPPs) are able to translocate almost any cell membrane carrying cargo molecules. However, different CPP use different entry mechanisms, which are often concentration-dependent and cargo-dependent. Being able to quantify the lipid affinity of CPP is of obvious importance and can be achieved by studying the partition extent of CPP into lipid bilayers. The partition constant (Kp) reflects the lipid-water partition extent. However, all currently available methodologies are only suitable to determine the partition of single molecules into lipid membranes or entities, being unsuitable to determine the partition of bimolecular or higher order supramolecular complexes. We derived and tested a mathematical model to determine the Kp of supramolecular CPP-cargo complexes from fluorescence spectroscopy data, using DNA oligomers as a model cargo. As a proof-of-concept example, the partition extent of two new membrane active peptides derived from dengue virus capsid protein (DENV C protein) with potential CPP properties, in both scenarios (free peptide and complexed with a molecular cargo), were tested. We were able to identify the lipid affinity of these CPP:DNA complexes, thus gaining valuable insights into better CPP formulations.
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Affiliation(s)
- João Miguel Freire
- Instituto de Medicina Molecular, University of Lisbon, Physical Biochemistry Unit, Lisbon, Portugal
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6
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Ribeiro MMB, Pinto ART, Domingues MM, Serrano I, Heras M, Bardaji ER, Tavares I, Castanho MA. Chemical conjugation of the neuropeptide kyotorphin and ibuprofen enhances brain targeting and analgesia. Mol Pharm 2011; 8:1929-40. [PMID: 21830793 DOI: 10.1021/mp2003016] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The pharmaceutical potential of natural analgesic peptides is mainly hampered by their inability to cross the blood-brain barrier, BBB. Increasing peptide-cell membrane affinity through drug design is a promising strategy to overcome this limitation. To address this challenge, we grafted ibuprofen (IBP), a nonsteroidal anti-inflammatory drug, to kyotorphin (l-Tyr-l-Arg, KTP), an analgesic neuropeptide unable to cross BBB. Two new KTP derivatives, IBP-KTP (IbKTP-OH) and IBP-KTP-amide (IbKTP-NH(2)), were synthesized and characterized for membrane interaction, analgesic activity and mechanism of action. Ibuprofen enhanced peptide-membrane interaction, endowing a specificity for anionic fluid bilayers. A direct correlation between anionic lipid affinity and analgesic effect was established, IbKTP-NH(2) being the most potent analgesic (from 25 μmol · kg(-1)). In vitro, IbKTP-NH(2) caused the biggest shift in the membrane surface charge of BBB endothelial cells, as quantified using zeta-potential dynamic light scattering. Our results suggest that IbKTP-NH(2) crosses the BBB and acts by activating both opioid dependent and independent pathways.
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Affiliation(s)
- Marta M B Ribeiro
- Instituto de Medicina Molecular, Faculdade de Medicina de Lisboa, Av Professor Egas Moniz, 1649-028 Lisboa, Portugal
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7
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Ribeiro MMB, Franquelim HG, Castanho MARB, Veiga AS. Molecular interaction studies of peptides using steady-state fluorescence intensity. Static (de)quenching revisited. J Pept Sci 2008; 14:401-6. [PMID: 17994617 DOI: 10.1002/psc.939] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Protein-protein interactions, as well as peptide-peptide and peptide-protein interactions are fields of study of growing importance as molecular-level detail is avidly pursued in drug design, metabolic regulation and molecular dynamics, among other classes of studies. In membranes, this issue is particularly relevant because lipid bilayers potentiate molecular interactions due to the high local concentration of peptides and other solutes.However, experimental techniques and methodologies to detect and quantify such interactions are not abundant. A reliable, fast and inexpensive alternative methodology is revisited in this work. Considering the interaction of two molecules, at least one of them being fluorescent, either intrinsically (e.g. Trp residues) or by grafting a specific probe, changes in their aggregation state may be reported, as long as the fluorophore is sensitive to local changes in polarity, conformation and/or exposure to the solvent. The interaction will probably lead to modifications in fluorescence intensity resulting in a decrease ('quenching') or enhancement ('dequenching'). Although the presented methodology is based on static quenching methodologies, the concept is extended from quenching to any kind of interference with the fluorophore. Equations for data analysis are shown and their applications are illustrated by calculating the binding constant for several data-sets.
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Affiliation(s)
- Marta M B Ribeiro
- Centro de Química e Bioquímica, Faculdade de Ciências da Universidade de Lisboa, Campo Grande, Ed C8, 1749-016 Lisboa, Portugal
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8
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Abstract
Transmissible spongiform encephalopathies are neurodegenerative diseases characterized by the accumulation of an abnormal isoform of the prion protein PrP(Sc). Its fragment 106-126 has been reported to maintain most of the pathological features of PrP(Sc), and a role in neurodegeneration has been proposed based on the modulation of membrane properties and channel formation. The ability of PrP(Sc) to modulate membranes and/or form channels in membranes has not been clearly demonstrated; however, if these processes are important, peptide-membrane interactions would be a key feature in the toxicity of PrP(Sc). In this work, the interaction of PrP(106-126) with model membranes comprising typical lipid identities, as well as more specialized lipids such as phosphatidylserine and GM1 ganglioside, was examined using surface plasmon resonance and fluorescence methodologies. This comprehensive study examines different parameters relevant to characterization of peptide-membrane interactions, including membrane charge, viscosity, lipid composition, pH, and ionic strength. We report that PrP(106-126) has a low affinity for lipid membranes under physiological conditions without evidence of membrane disturbances. Membrane insertion and leakage occur only under conditions in which strong electrostatic interactions operate. These results support the hypothesis that the physiological prion protein PrP(C) mediates PrP(106-126) toxic effects in neuronal cells.
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9
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Chu VC, McElroy LJ, Chu V, Bauman BE, Whittaker GR. The avian coronavirus infectious bronchitis virus undergoes direct low-pH-dependent fusion activation during entry into host cells. J Virol 2006; 80:3180-8. [PMID: 16537586 PMCID: PMC1440383 DOI: 10.1128/jvi.80.7.3180-3188.2006] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Coronaviruses are the causative agents of respiratory disease in humans and animals, including severe acute respiratory syndrome. Fusion of coronaviruses is generally thought to occur at neutral pH, although there is also evidence for a role of acidic endosomes during entry of a variety of coronaviruses. Therefore, the molecular basis of coronavirus fusion during entry into host cells remains incompletely defined. Here, we examined coronavirus-cell fusion and entry employing the avian coronavirus infectious bronchitis virus (IBV). Virus entry into cells was inhibited by acidotropic bases and by other inhibitors of pH-dependent endocytosis. We carried out fluorescence-dequenching fusion assays of R18-labeled virions and show that for IBV, coronavirus-cell fusion occurs in a low-pH-dependent manner, with a half-maximal rate of fusion occurring at pH 5.5. Fusion was reduced, but still occurred, at lower temperatures (20 degrees C). We observed no effect of inhibitors of endosomal proteases on the fusion event. These data are the first direct measure of virus-cell fusion for any coronavirus and demonstrate that the coronavirus IBV employs a direct, low-pH-dependent virus-cell fusion activation reaction. We further show that IBV was not inactivated, and fusion was unaffected, by prior exposure to pH 5.0 buffer. Virions also showed evidence of reversible conformational changes in their surface proteins, indicating that aspects of the fusion reaction may be reversible in nature.
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Affiliation(s)
- Victor C Chu
- Dept. of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA
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10
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Abstract
There are a number of antivirals as well as antiviral strategies that could be envisaged to prevent or treat severe acute respiratory syndrome (SARS) (or similar) coronavirus (CoV) infections. Targets for the prophylactic or therapeutic interventions include interaction of the spike (S) glycoprotein (S1 domain) with the host cell receptor, fusion of the S2 domain with the host cell membrane, processing of the replicase polyproteins by the virus-encoded proteases (3C-like cysteine protease [3CLpro] and papain-like cysteine protease) and other virus-encoded enzymes such as the NTPase/helicase and RNA-dependent RNA polymerase. Human monoclonal antibody blocking S1 may play an important role in the immunoprophylaxis of SARS. Fusion inhibitors reminiscent of enfuvirtide in the case of HIV may also be developed for SARS-CoV. Various peptidomimetic and nonpeptidic inhibitors of 3CLpro have been described, the best ones inhibiting SARS-CoV replication with a selectivity index greater than 1000. Human interferons, in particular alpha- and beta-interferon, as well as short interfering RNAs could further be pursued for the control of SARS. Various other compounds, often with an ill-defined mode of action but selectivity indexes up to 100, have been reported to exhibit in vitro activity against SARS-CoV: valinomycin, glycopeptide antibiotics, plant lectins, hesperetin, glycyrrhizin, aurintricarboxylic acid, chloroquine, niclosamide, nelfinavir and calpain inhibitors.
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Affiliation(s)
- Erik De Clercq
- Rega Institute for Medical Research, KU Leuven, Minderbroedersstraat 10B-3000 Leuven, Belgium.
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11
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Veiga AS, Castanho MARB. The membranes' role in the HIV-1 neutralizing monoclonal antibody 2F5 mode of action needs re-evaluation. Antiviral Res 2006; 71:69-72. [PMID: 16530275 DOI: 10.1016/j.antiviral.2006.02.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2005] [Revised: 01/05/2006] [Accepted: 02/03/2006] [Indexed: 11/21/2022]
Abstract
2F5, a monoclonal antibody that neutralizes HIV-1 primary isolates, recognizes an epitope in the membrane proximal region of the glycoprotein gp41 ectodomain. It is believed that binding to the viral membrane is a step in the antibody mode of action, as usual in ligand membrane receptor interactions. We investigated the interaction of 2F5 with membrane model systems, namely large unilamellar vesicles, by means of fluorescence techniques. There were no significant interactions of 2F5 with model viral membranes or with model target cell membranes. Thus, the usual three-step 'membrane catalysis' method is not followed by 2F5 in its mode of action.
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Affiliation(s)
- Ana Salomé Veiga
- Centro de Química e Bioquímica, Faculdade de Ciências da Universidade de Lisboa, Campo Grande Ed. C8, Portugal
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