1
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Marchitto L, Richard J, Prévost J, Tauzin A, Yang D, Chiu TJ, Chen HC, Díaz-Salinas MA, Nayrac M, Benlarbi M, Beaudoin-Bussières G, Anand SP, Dionne K, Bélanger É, Chatterjee D, Medjahed H, Bourassa C, Tolbert WD, Hahn BH, Munro JB, Pazgier M, Smith AB, Finzi A. The combination of three CD4-induced antibodies targeting highly conserved Env regions with a small CD4-mimetic achieves potent ADCC activity. J Virol 2024:e0101624. [PMID: 39248460 DOI: 10.1128/jvi.01016-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2024] [Accepted: 08/13/2024] [Indexed: 09/10/2024] Open
Abstract
The majority of naturally elicited antibodies against the HIV-1 envelope glycoproteins (Env) are non-neutralizing (nnAbs) because they are unable to recognize the Env trimer in its native "closed" conformation. Nevertheless, it has been shown that nnAbs have the potential to eliminate HIV-1-infected cells by antibody-dependent cellular cytotoxicity (ADCC) provided that Env is present on the cell surface in its "open" conformation. This is because most nnAbs recognize epitopes that become accessible only after Env interaction with CD4 and the exposure of epitopes that are normally occluded in the closed trimer. HIV-1 limits this vulnerability by downregulating CD4 from the surface of infected cells, thus preventing a premature encounter of Env with CD4. Small CD4-mimetics (CD4mc) sensitize HIV-1-infected cells to ADCC by opening the Env glycoprotein and exposing CD4-induced (CD4i) epitopes. There are two families of CD4i nnAbs, termed anti-cluster A and anti-CoRBS Abs, which are known to mediate ADCC in the presence of CD4mc. Here, we performed Fab competition experiments and found that anti-gp41 cluster I antibodies comprise a major fraction of the plasma ADCC activity in people living with HIV (PLWH). Moreover, addition of gp41 cluster I antibodies to cluster A and CoRBS antibodies greatly enhanced ADCC-mediated cell killing in the presence of a potent indoline CD4mc, CJF-III-288. This cocktail outperformed broadly neutralizing antibodies and even showed activity against HIV-1-infected monocyte-derived macrophages. Thus, combining CD4i antibodies with different specificities achieves maximal ADCC activity, which may be of utility in HIV cure strategies.IMPORTANCEThe elimination of HIV-1-infected cells remains an important medical goal. Although current antiretroviral therapy decreases viral loads below detection levels, it does not eliminate latently infected cells that form the viral reservoir. Here, we developed a cocktail of non-neutralizing antibodies targeting highly conserved Env regions and combined it with a potent indoline CD4mc. This combination exhibited potent ADCC activity against HIV-1-infected primary CD4 + T cells as well as monocyte-derived macrophages, suggesting its potential utility in decreasing the size of the viral reservoir.
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Affiliation(s)
- Lorie Marchitto
- Centre de Recherche du CHUM, Montréal, Québec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montréal, Québec, Canada
| | - Jonathan Richard
- Centre de Recherche du CHUM, Montréal, Québec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montréal, Québec, Canada
| | - Jérémie Prévost
- Centre de Recherche du CHUM, Montréal, Québec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montréal, Québec, Canada
| | - Alexandra Tauzin
- Centre de Recherche du CHUM, Montréal, Québec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montréal, Québec, Canada
| | - Derek Yang
- Department of Chemistry, School of Arts and Sciences, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Ta-Jung Chiu
- Department of Chemistry, School of Arts and Sciences, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Hung-Ching Chen
- Department of Chemistry, School of Arts and Sciences, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Marco A Díaz-Salinas
- Department of Microbiology and Physiological Systems, University of Massachusetts Chan Medical School, Worcester, Massachusetts, USA
| | - Manon Nayrac
- Centre de Recherche du CHUM, Montréal, Québec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montréal, Québec, Canada
| | - Mehdi Benlarbi
- Centre de Recherche du CHUM, Montréal, Québec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montréal, Québec, Canada
| | - Guillaume Beaudoin-Bussières
- Centre de Recherche du CHUM, Montréal, Québec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montréal, Québec, Canada
| | - Sai Priya Anand
- Centre de Recherche du CHUM, Montréal, Québec, Canada
- Department of Microbiology and Immunology, McGill University, Montreal, Canada
| | - Katrina Dionne
- Centre de Recherche du CHUM, Montréal, Québec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montréal, Québec, Canada
| | - Étienne Bélanger
- Centre de Recherche du CHUM, Montréal, Québec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montréal, Québec, Canada
| | | | | | | | - William D Tolbert
- Infectious Diseases Division, Department of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Beatrice H Hahn
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - James B Munro
- Department of Microbiology and Physiological Systems, University of Massachusetts Chan Medical School, Worcester, Massachusetts, USA
- Department of Biochemistry and Molecular Biotechnology, University of Massachusetts Chan Medical School, Worcester, Massachusetts, USA
| | - Marzena Pazgier
- Infectious Diseases Division, Department of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Amos B Smith
- Department of Chemistry, School of Arts and Sciences, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Andrés Finzi
- Centre de Recherche du CHUM, Montréal, Québec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montréal, Québec, Canada
- Department of Microbiology and Immunology, McGill University, Montreal, Canada
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2
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Richard J, Grunst MW, Niu L, Díaz-Salinas MA, Tolbert WD, Marchitto L, Zhou F, Bourassa C, Yang D, Chiu TJ, Chen HC, Benlarbi M, Gottumukkala S, Li W, Dionne K, Bélanger É, Chatterjee D, Medjahed H, Hendrickson WA, Sodroski J, Lang ZC, Morton AJ, Huang RK, Matthies D, Smith AB, Mothes W, Munro JB, Pazgier M, Finzi A. The asymmetric opening of HIV-1 Env by a potent CD4 mimetic enables anti-coreceptor binding site antibodies to mediate ADCC. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.08.27.609961. [PMID: 39253431 PMCID: PMC11383012 DOI: 10.1101/2024.08.27.609961] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 09/11/2024]
Abstract
HIV-1 envelope glycoproteins (Env) from primary HIV-1 isolates typically adopt a pretriggered "closed" conformation that resists to CD4-induced (CD4i) non-neutralizing antibodies (nnAbs) mediating antibody-dependent cellular cytotoxicity (ADCC). CD4-mimetic compounds (CD4mcs) "open-up" Env allowing binding of CD4i nnAbs, thereby sensitizing HIV-1-infected cells to ADCC. Two families of CD4i nnAbs, the anti-cluster A and anti-coreceptor binding site (CoRBS) Abs, are required to mediate ADCC in combination with the indane CD4mc BNM-III-170. Recently, new indoline CD4mcs with improved potency and breadth have been described. Here, we show that the lead indoline CD4mc, CJF-III-288, sensitizes HIV-1-infected cells to ADCC mediated by anti-CoRBS Abs alone, contributing to improved ADCC activity. Structural and conformational analyses reveal that CJF-III-288, in combination with anti-CoRBS Abs, potently stabilizes an asymmetric "open" State-3 Env conformation, This Env conformation orients the anti-CoRBS Ab to improve ADCC activity and therapeutic potential.
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Affiliation(s)
- Jonathan Richard
- Centre de Recherche du CHUM, Montréal, Québec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montréal, Québec, Canada
| | - Michael W Grunst
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, CT, USA
| | - Ling Niu
- Infectious Diseases Division, Department of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - Marco A Díaz-Salinas
- Department of Microbiology, University of Massachusetts Chan Medical School, Worcester, Massachusetts, USA
| | - William D Tolbert
- Infectious Diseases Division, Department of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - Lorie Marchitto
- Centre de Recherche du CHUM, Montréal, Québec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montréal, Québec, Canada
| | - Fei Zhou
- Unit on Structural Biology, Division of Basic and Translational Biophysics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, Bethesda, MD, USA
| | | | - Derek Yang
- Department of Chemistry, School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA, USA
| | - Ta Jung Chiu
- Department of Chemistry, School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA, USA
| | - Hung-Ching Chen
- Department of Chemistry, School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA, USA
| | - Mehdi Benlarbi
- Centre de Recherche du CHUM, Montréal, Québec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montréal, Québec, Canada
| | - Suneetha Gottumukkala
- Infectious Diseases Division, Department of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - Wenwei Li
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, CT, USA
| | - Katrina Dionne
- Centre de Recherche du CHUM, Montréal, Québec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montréal, Québec, Canada
| | - Étienne Bélanger
- Centre de Recherche du CHUM, Montréal, Québec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montréal, Québec, Canada
| | - Debashree Chatterjee
- Centre de Recherche du CHUM, Montréal, Québec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montréal, Québec, Canada
| | | | - Wayne A Hendrickson
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY, USA
| | - Joseph Sodroski
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Zabrina C Lang
- Laboratory of Cell Biology, National Cancer Institute, NIH, Bethesda, USA
| | - Abraham J Morton
- Laboratory of Cell Biology, National Cancer Institute, NIH, Bethesda, USA
| | - Rick K Huang
- Laboratory of Cell Biology, National Cancer Institute, NIH, Bethesda, USA
| | - Doreen Matthies
- Unit on Structural Biology, Division of Basic and Translational Biophysics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, Bethesda, MD, USA
| | - Amos B Smith
- Department of Chemistry, School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA, USA
| | - Walther Mothes
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, CT, USA
| | - James B Munro
- Department of Microbiology, University of Massachusetts Chan Medical School, Worcester, Massachusetts, USA
- Department of Biochemistry and Molecular Biotechnology, University of Massachusetts Chan Medical School, Worcester, MA, USA
| | - Marzena Pazgier
- Infectious Diseases Division, Department of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - Andrés Finzi
- Centre de Recherche du CHUM, Montréal, Québec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montréal, Québec, Canada
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3
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Díaz-Salinas MA, Chatterjee D, Nayrac M, Medjahed H, Prévost J, Pazgier M, Finzi A, Munro JB. Conformational dynamics of the HIV-1 envelope glycoprotein from CRF01_AE is associated with susceptibility to antibody-dependent cellular cytotoxicity. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.08.22.609179. [PMID: 39229074 PMCID: PMC11370484 DOI: 10.1101/2024.08.22.609179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 09/05/2024]
Abstract
The HIV-1 envelope glycoprotein (Env) is expressed at the surface of infected cells and as such can be targeted by non-neutralizing antibodies (nnAbs) that mediate antibody-dependent cellular cytotoxicity (ADCC). Previous single-molecule Förster resonance energy transfer (smFRET) studies demonstrated that Env from clinical isolates predominantly adopt a "closed" conformation (State 1), which is resistant to nnAbs. After interacting with the cellular receptor CD4, the conformational equilibrium of Env shifts toward States 2 and 3, exposing the coreceptor binding site (CoRBS) and permitting binding of antibodies targeting this site. We showed that the binding of anti-CoRBS Abs enables the engagement of other nnAbs that target the cluster A epitopes on Env. Anti-cluster A nnAbs stabilize an asymmetric Env conformation, State 2A, and have potent ADCC activity. CRF01_AE strains were suggested to be intrinsically susceptible to ADCC mediated by nnAbs. This may be due to the presence of a histidine at position 375, known to shift Env towards more "open" conformations. In this work, through adaptation of an established smFRET imaging approach, we report that the conformational dynamics of native, unliganded HIV-1CRF01_AE Env indicates frequent sampling of the State 2A conformation. This is in striking contrast with Envs from clades A and B, for example HIV-1JR-FL, which do not transition to State 2A in the absence of ligands. These findings inform on the conformational dynamics of HIV-1CRF01_AE Env, which are relevant for structure-based design of both synthetic inhibitors of receptor binding, and enhancers of ADCC as therapeutic alternatives.
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Affiliation(s)
- Marco A Díaz-Salinas
- Department of Microbiology, University of Massachusetts Chan Medical School, Worcester, MA, USA
| | | | - Manon Nayrac
- Centre de Recherche du CHUM, Montréal, Québec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montréal, Québec, Canada
| | | | - Jérémie Prévost
- Centre de Recherche du CHUM, Montréal, Québec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montréal, Québec, Canada
| | - Marzena Pazgier
- Infectious Diseases Division, Department of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - Andrés Finzi
- Centre de Recherche du CHUM, Montréal, Québec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montréal, Québec, Canada
| | - James B Munro
- Department of Microbiology, University of Massachusetts Chan Medical School, Worcester, MA, USA
- Department of Biochemistry and Molecular Biotechnology, University of Massachusetts Chan Medical School, Worcester, MA, USA
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4
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Marchitto L, Richard J, Prévost J, Tauzin A, Yang D, Chiu T, Chen HC, Díaz-Salinas MA, Nayrac M, Benlarbi M, Beaudoin-Bussières G, Anand SP, Dionne K, Bélanger É, Chatterjee D, Medjahed H, Bourassa C, Tolbert WD, Hahn BH, Munro JB, Pazgier M, Smith AB, Finzi A. The combination of three CD4-induced antibodies targeting highly conserved Env regions with a small CD4-mimetic achieves potent ADCC activity. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.07.597978. [PMID: 38895270 PMCID: PMC11185797 DOI: 10.1101/2024.06.07.597978] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/21/2024]
Abstract
The majority of naturally-elicited antibodies against the HIV-1 envelope glycoproteins (Env) are non-neutralizing (nnAbs), because they are unable to recognize the Env timer in its native "closed" conformation. Nevertheless, it has been shown that nnAbs have the potential to eliminate HIV-1-infected cells by Antibody-Dependent Cellular Cytotoxicity (ADCC) provided that Env is present on the cell surface in its "open" conformation. This is because most nnAbs recognize epitopes that become accessible only after Env interaction with CD4 and the exposure of epitopes that are normally occluded in the closed trimer. HIV-1 limits this vulnerability by downregulating CD4 from the surface of infected cells, thus preventing a premature encounter of Env with CD4. Small CD4-mimetics (CD4mc) sensitize HIV-1-infected cells to ADCC by opening the Env glycoprotein and exposing CD4-induced (CD4i) epitopes. There are two families of CD4i nnAbs, termed anti-cluster A and anti-CoRBS Abs, which are known to mediate ADCC in the presence of CD4mc. Here, we performed Fab competition experiments and found that anti-gp41 cluster I antibodies comprise a major fraction of the plasma ADCC activity in people living with HIV (PLWH). Moreover, addition of gp41 cluster I antibodies to cluster A and CoRBS antibodies greatly enhanced ADCC mediated cell killing in the presence of a potent indoline CD4mc, CJF-III-288. This cocktail outperformed broadly-neutralizing antibodies and even showed activity against HIV-1 infected monocyte-derived macrophages. Thus, combining CD4i antibodies with different specificities achieves maximal ADCC activity, which may be of utility in HIV cure strategies.
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Affiliation(s)
- Lorie Marchitto
- Centre de Recherche du CHUM, Montréal, Québec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montréal, Québec, Canada
| | | | - Jérémie Prévost
- Centre de Recherche du CHUM, Montréal, Québec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montréal, Québec, Canada
| | - Alexandra Tauzin
- Centre de Recherche du CHUM, Montréal, Québec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montréal, Québec, Canada
| | - Derek Yang
- Department of Chemistry, School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA 19104-6323, USA
| | - TaJung Chiu
- Department of Chemistry, School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA 19104-6323, USA
| | - Hung-Ching Chen
- Department of Chemistry, School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA 19104-6323, USA
| | - Marco A. Díaz-Salinas
- Department of Microbiology and Physiological Systems, University of Massachusetts Chan Medical School, Worcester, Massachusetts, USA
| | - Manon Nayrac
- Centre de Recherche du CHUM, Montréal, Québec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montréal, Québec, Canada
| | - Mehdi Benlarbi
- Centre de Recherche du CHUM, Montréal, Québec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montréal, Québec, Canada
| | - Guillaume Beaudoin-Bussières
- Centre de Recherche du CHUM, Montréal, Québec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montréal, Québec, Canada
| | - Sai Priya Anand
- Centre de Recherche du CHUM, Montréal, Québec, Canada
- Department of Microbiology and Immunology, McGill University, Montreal, QC H3A 2B4, Canada
| | - Katrina Dionne
- Centre de Recherche du CHUM, Montréal, Québec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montréal, Québec, Canada
| | - Étienne Bélanger
- Centre de Recherche du CHUM, Montréal, Québec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montréal, Québec, Canada
| | - Debashree Chatterjee
- Centre de Recherche du CHUM, Montréal, Québec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montréal, Québec, Canada
| | | | | | - William D. Tolbert
- Infectious Diseases Division, Department of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - Beatrice H. Hahn
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - James B. Munro
- Department of Microbiology and Physiological Systems, University of Massachusetts Chan Medical School, Worcester, Massachusetts, USA
- Department of Biochemistry and Molecular Biotechnology, University of Massachusetts Chan Medical School, Worcester, Massachusetts, USA
| | - Marzena Pazgier
- Infectious Diseases Division, Department of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - Amos B. Smith
- Department of Chemistry, School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA 19104-6323, USA
| | - Andrés Finzi
- Centre de Recherche du CHUM, Montréal, Québec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montréal, Québec, Canada
- Department of Microbiology and Immunology, McGill University, Montreal, QC H3A 2B4, Canada
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5
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Alfadhli A, Romanaggi C, Barklis RL, Barklis E. Second site reversion of HIV-1 envelope protein baseplate mutations maps to the matrix protein. J Virol 2024; 98:e0174223. [PMID: 38193694 PMCID: PMC10878238 DOI: 10.1128/jvi.01742-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Accepted: 12/07/2023] [Indexed: 01/10/2024] Open
Abstract
The HIV-1 Envelope (Env) protein cytoplasmic tail (CT) recently has been shown to assemble an unusual trimeric baseplate structure that locates beneath Env ectodomain trimers. Mutations at linchpin residues that help organize the baseplate impair virus replication in restrictive T cell lines but not in permissive cell lines. We have identified and characterized a second site suppressor of these baseplate mutations, located at residue 34 in the viral matrix (MA) protein, that rescues viral replication in restrictive cells. The suppressor mutation was dependent on the CT to exert its activity and did not appear to affect Env protein traffic or fusion functions in restrictive cells. Instead, the suppressor mutation increased Env incorporation into virions 3-fold and virus infectivity in single-round infections 10-fold. We also found that a previously described suppressor of Env-incorporation defects that stabilizes the formation of MA trimers was ineffective at rescuing Env baseplate mutations. Our results support an interpretation in which changes at MA residue 34 induce conformational changes that stabilize MA lattice trimer-trimer interactions and/or direct MA-CT associations.IMPORTANCEHow HIV-1 Env trimers assemble into virus particles remains incompletely understood. In restrictive cells, viral incorporation of Env is dependent on the Env CT and on the MA protein, which assembles lattices composed of hexamers of trimers in immature and mature viruses. Recent evidence indicates that CT assembles trimeric baseplate structures that require membrane-proximal residues to interface with trimeric transmembrane domains and C-terminal helices in the CT. We found that mutations of these membrane-proximal residues impaired replication in restrictive cells. This defect was countered by a MA mutation that does not localize to any obvious interprotein regions but was only inefficiently suppressed by a MA mutation that stabilizes MA trimers and has been shown to suppress other CT-dependent Env defects. Our results suggest that efficient suppression of baseplate mutations involves stabilization of MA inter-trimer contacts and/or direct MA-CT associations. These observations shed new light on how Env assembles into virions.
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Affiliation(s)
- Ayna Alfadhli
- Department of Molecular Microbiology and Immunology, Oregon Health & Sciences University, Portland, Oregon, USA
| | - CeAnn Romanaggi
- Department of Molecular Microbiology and Immunology, Oregon Health & Sciences University, Portland, Oregon, USA
| | - Robin Lid Barklis
- Department of Molecular Microbiology and Immunology, Oregon Health & Sciences University, Portland, Oregon, USA
| | - Eric Barklis
- Department of Molecular Microbiology and Immunology, Oregon Health & Sciences University, Portland, Oregon, USA
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6
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Richard J, Prévost J, Bourassa C, Brassard N, Boutin M, Benlarbi M, Goyette G, Medjahed H, Gendron-Lepage G, Gaudette F, Chen HC, Tolbert WD, Smith AB, Pazgier M, Dubé M, Clark A, Mothes W, Kaufmann DE, Finzi A. Temsavir blocks the immunomodulatory activities of HIV-1 soluble gp120. Cell Chem Biol 2023; 30:540-552.e6. [PMID: 36958337 PMCID: PMC10198848 DOI: 10.1016/j.chembiol.2023.03.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Revised: 02/03/2023] [Accepted: 03/02/2023] [Indexed: 03/25/2023]
Abstract
While HIV-1-mediated CD4 downregulation protects infected cells from antibody-dependent cellular cytotoxicity (ADCC), shed gp120 binds to CD4 on uninfected bystander CD4+ T cells, sensitizing them to ADCC mediated by HIV+ plasma. Soluble gp120-CD4 interaction on multiple immune cells also triggers a cytokine burst. The small molecule temsavir acts as an HIV-1 attachment inhibitor by preventing envelope glycoprotein (Env)-CD4 interaction and alters the overall antigenicity of Env by affecting its processing and glycosylation. Here we show that temsavir also blocks the immunomodulatory activities of shed gp120. Temsavir prevents shed gp120 from interacting with uninfected bystander CD4+ cells, protecting them from ADCC responses and preventing a cytokine burst. Mechanistically, this depends on temsavir's capacity to prevent soluble gp120-CD4 interaction, to reduce gp120 shedding, and to alter gp120 antigenicity. This suggests that the clinical benefits provided by temsavir could extend beyond blocking viral entry.
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Affiliation(s)
- Jonathan Richard
- Centre de Recherche du CHUM, Montréal, QC H2X 0A9, Canada; Département de Microbiologie, Infectiologie, et Immunologie, Université de Montréal, Montréal, QC H2X 0A9, Canada
| | - Jérémie Prévost
- Centre de Recherche du CHUM, Montréal, QC H2X 0A9, Canada; Département de Microbiologie, Infectiologie, et Immunologie, Université de Montréal, Montréal, QC H2X 0A9, Canada
| | | | | | - Marianne Boutin
- Centre de Recherche du CHUM, Montréal, QC H2X 0A9, Canada; Département de Microbiologie, Infectiologie, et Immunologie, Université de Montréal, Montréal, QC H2X 0A9, Canada
| | - Mehdi Benlarbi
- Centre de Recherche du CHUM, Montréal, QC H2X 0A9, Canada; Département de Microbiologie, Infectiologie, et Immunologie, Université de Montréal, Montréal, QC H2X 0A9, Canada
| | | | | | | | - Fleur Gaudette
- Plateforme de Pharmacocinétique, Centre de Recherche du CHUM, Montréal, QC H2X 0A9, Canada
| | - Hung-Ching Chen
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104-6323, USA
| | - William D Tolbert
- Infectious Diseases Division, Department of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD 20814-4712, USA
| | - Amos B Smith
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104-6323, USA
| | - Marzena Pazgier
- Infectious Diseases Division, Department of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD 20814-4712, USA
| | - Mathieu Dubé
- Centre de Recherche du CHUM, Montréal, QC H2X 0A9, Canada
| | - Andrew Clark
- ViiV Healthcare, Global Medical Affairs, Middlesex TW8 9GS, UK
| | - Walther Mothes
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Daniel E Kaufmann
- Centre de Recherche du CHUM, Montréal, QC H2X 0A9, Canada; Département de Médecine, Université de Montréal, Montréal, QC H2X 0A9, Canada
| | - Andrés Finzi
- Centre de Recherche du CHUM, Montréal, QC H2X 0A9, Canada; Département de Microbiologie, Infectiologie, et Immunologie, Université de Montréal, Montréal, QC H2X 0A9, Canada.
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7
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Alfadhli A, Romanaggi C, Barklis RL, Barklis E. Analysis of HIV-1 envelope cytoplasmic tail effects on viral replication. Virology 2023; 579:54-66. [PMID: 36603533 PMCID: PMC10003682 DOI: 10.1016/j.virol.2022.12.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 12/27/2022] [Accepted: 12/28/2022] [Indexed: 01/03/2023]
Abstract
Trimers of the HIV-1 envelope (Env) protein perform receptor binding and virus-cell fusion functions during the virus life cycle. The cytoplasmic tail (CT) of Env forms an unusual baseplate structure, and is palmitoylated, rich in arginines, carries trafficking motifs, binds cholesterol, and interacts with host proteins. To dissect CT activities, we examined a panel of Env variants, including CT truncations, mutations, and an extension. We found that whereas all variants could replicate in permissive cells, viruses with CT truncations or baseplate mutations were defective in restrictive cells. We also identified a determinant in HIV-1 amphotericin sensitivity, and characterized variants that escape amphotericin inhibition via viral protease-mediated CT cleavage. Results additionally showed that full-length, his tagged Env can oligomerize and be co-assembled with CT truncations that delete portions of the baseplate, host protein binding sites, and trafficking signals. Our observations illuminate novel aspects of HIV-1 CT structure, interactions, and functions.
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Affiliation(s)
- Ayna Alfadhli
- Department of Molecular Microbiology and Immunology, Oregon Health and Sciences University, Portland, OR, USA
| | - CeAnn Romanaggi
- Department of Molecular Microbiology and Immunology, Oregon Health and Sciences University, Portland, OR, USA
| | - Robin Lid Barklis
- Department of Molecular Microbiology and Immunology, Oregon Health and Sciences University, Portland, OR, USA
| | - Eric Barklis
- Department of Molecular Microbiology and Immunology, Oregon Health and Sciences University, Portland, OR, USA.
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8
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Prévost J, Anand SP, Rajashekar JK, Zhu L, Richard J, Goyette G, Medjahed H, Gendron-Lepage G, Chen HC, Chen Y, Horwitz JA, Grunst MW, Zolla-Pazner S, Haynes BF, Burton DR, Flavell RA, Kirchhoff F, Hahn BH, Smith AB, Pazgier M, Nussenzweig MC, Kumar P, Finzi A. HIV-1 Vpu restricts Fc-mediated effector functions in vivo. Cell Rep 2022; 41:111624. [PMID: 36351384 PMCID: PMC9703018 DOI: 10.1016/j.celrep.2022.111624] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 09/02/2022] [Accepted: 10/17/2022] [Indexed: 11/09/2022] Open
Abstract
Non-neutralizing antibodies (nnAbs) can eliminate HIV-1-infected cells via antibody-dependent cellular cytotoxicity (ADCC) and were identified as a correlate of protection in the RV144 vaccine trial. Fc-mediated effector functions of nnAbs were recently shown to alter the course of HIV-1 infection in vivo using a vpu-defective virus. Since Vpu is known to downregulate cell-surface CD4, which triggers conformational changes in the viral envelope glycoprotein (Env), we ask whether the lack of Vpu expression was linked to the observed nnAbs activity. We find that restoring Vpu expression greatly reduces nnAb recognition of infected cells, rendering them resistant to ADCC. Moreover, administration of nnAbs in humanized mice reduces viral loads only in animals infected with a vpu-defective but not with a wild-type virus. CD4-mimetics administration, known to "open" Env and expose nnAb epitopes, renders wild-type viruses sensitive to nnAbs Fc-effector functions. This work highlights the importance of Vpu-mediated evasion of humoral responses.
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Affiliation(s)
- Jérémie Prévost
- Centre de Recherche du CHUM, Montreal, QC H2X 0A9, Canada; Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, QC H2X 0A9, Canada.
| | - Sai Priya Anand
- Centre de Recherche du CHUM, Montreal, QC H2X 0A9, Canada; Department of Microbiology and Immunology, McGill University, Montreal, QC H3A 2B4, Canada
| | - Jyothi Krishnaswamy Rajashekar
- Department of Internal Medicine, Section of Infectious Diseases, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Li Zhu
- Department of Internal Medicine, Section of Infectious Diseases, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Jonathan Richard
- Centre de Recherche du CHUM, Montreal, QC H2X 0A9, Canada; Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, QC H2X 0A9, Canada
| | | | | | | | - Hung-Ching Chen
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104-6323, USA
| | - Yaozong Chen
- Infectious Diseases Division, Department of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD 20814-4712, USA
| | - Joshua A Horwitz
- Laboratory of Molecular Immunology, The Rockefeller University, New York, NY 10065, USA
| | - Michael W Grunst
- Department of Internal Medicine, Section of Infectious Diseases, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Susan Zolla-Pazner
- Department of Medicine, Division of Infectious Diseases, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Barton F Haynes
- Duke Human Vaccine Institute, Departments of Medicine and Immunology, Duke University School of Medicine, Durham, NC 27710, USA; Consortium for HIV/AIDS Vaccine Development (CHAVD), Duke University, Durham, NC 27710, USA
| | - Dennis R Burton
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA 92037, USA; Consortium for HIV/AIDS Vaccine Development (CHAVD), The Scripps Research Institute, La Jolla, CA 92037, USA; Ragon Institute of Massachusetts General Hospital, Massachusetts Institute of Technology, Harvard University, Cambridge, MA 02139, USA
| | - Richard A Flavell
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT 06519, USA
| | - Frank Kirchhoff
- Institute of Molecular Virology, Ulm University Medical Center, 89081 Ulm, Germany
| | - Beatrice H Hahn
- Departments of Medicine and Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6076, USA
| | - Amos B Smith
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104-6323, USA
| | - Marzena Pazgier
- Infectious Diseases Division, Department of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD 20814-4712, USA
| | - Michel C Nussenzweig
- Laboratory of Molecular Immunology, The Rockefeller University, New York, NY 10065, USA
| | - Priti Kumar
- Department of Internal Medicine, Section of Infectious Diseases, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Andrés Finzi
- Centre de Recherche du CHUM, Montreal, QC H2X 0A9, Canada; Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, QC H2X 0A9, Canada; Department of Microbiology and Immunology, McGill University, Montreal, QC H3A 2B4, Canada.
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9
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Raghunath G, Chen YC, Marin M, Wu H, Melikyan GB. SERINC5-Mediated Restriction of HIV-1 Infectivity Correlates with Resistance to Cholesterol Extraction but Not with Lipid Order of Viral Membrane. Viruses 2022; 14:v14081636. [PMID: 35893701 PMCID: PMC9332783 DOI: 10.3390/v14081636] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Revised: 07/19/2022] [Accepted: 07/23/2022] [Indexed: 12/13/2022] Open
Abstract
Serine incorporator 5 (SER5) is a protein that upon incorporation into virions inhibits HIV-1 infectivity by interfering with the ability of the Env glycoprotein to promote viral fusion. The mechanisms by which SER5 antagonizes HIV-1 fusion are not well understood. A recent study of SER5's structure revealed a lipid-binding pocket, suggesting the ability to sequester lipids. This finding, along with the well-documented modulation of HIV-1 infectivity by viral lipids, especially cholesterol, prompted our examination of SER5's effect on the general lipid order of the HIV-1 membrane. Pseudoviruses bearing the SER5-sensitive HXB2-Env and containing SER5 or SER2, a control protein that lacks antiviral activity, were analyzed using two distinct lipid-order probes. We show that SER5 incorporation does not noticeably affect the lipid order of pseudoviruses. Although viral cholesterol extraction reduces HIV-1 infectivity, SER5+ viruses are less sensitive to cholesterol extraction than the control samples. In contrast, the virus' sensitivity to cholesterol oxidation was not affected by SER5 incorporation. The hydrolytic release of sphingomyelin-sequestered cholesterol had a minimal impact on the apparent resistance to cholesterol extraction. Based on these results, we propose that a subpopulation of more stable Env glycoproteins responsible for the residual infectivity of SER5+ viruses is less sensitive to the cholesterol content of the viral membrane.
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Affiliation(s)
- Gokul Raghunath
- Department of Pediatrics, Division of Infectious Diseases, School of Medicine, Emory University, Atlanta, GA 30322, USA; (G.R.); (Y.-C.C.); (M.M.); (H.W.)
- Children’s Healthcare of Atlanta, Atlanta, GA 30322, USA
| | - Yen-Cheng Chen
- Department of Pediatrics, Division of Infectious Diseases, School of Medicine, Emory University, Atlanta, GA 30322, USA; (G.R.); (Y.-C.C.); (M.M.); (H.W.)
- Children’s Healthcare of Atlanta, Atlanta, GA 30322, USA
| | - Mariana Marin
- Department of Pediatrics, Division of Infectious Diseases, School of Medicine, Emory University, Atlanta, GA 30322, USA; (G.R.); (Y.-C.C.); (M.M.); (H.W.)
- Children’s Healthcare of Atlanta, Atlanta, GA 30322, USA
| | - Hui Wu
- Department of Pediatrics, Division of Infectious Diseases, School of Medicine, Emory University, Atlanta, GA 30322, USA; (G.R.); (Y.-C.C.); (M.M.); (H.W.)
- Children’s Healthcare of Atlanta, Atlanta, GA 30322, USA
| | - Gregory B. Melikyan
- Department of Pediatrics, Division of Infectious Diseases, School of Medicine, Emory University, Atlanta, GA 30322, USA; (G.R.); (Y.-C.C.); (M.M.); (H.W.)
- Children’s Healthcare of Atlanta, Atlanta, GA 30322, USA
- Correspondence:
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10
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Prévost J, Medjahed H, Vézina D, Chen HC, Hahn BH, Smith AB, Finzi A. HIV-1 Envelope Glycoproteins Proteolytic Cleavage Protects Infected Cells from ADCC Mediated by Plasma from Infected Individuals. Viruses 2021; 13:2236. [PMID: 34835042 PMCID: PMC8625184 DOI: 10.3390/v13112236] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Revised: 11/03/2021] [Accepted: 11/04/2021] [Indexed: 12/28/2022] Open
Abstract
The HIV-1 envelope glycoprotein (Env) is synthesized in the endoplasmic reticulum as a trimeric gp160 precursor, which requires proteolytic cleavage by a cellular furin protease to mediate virus-cell fusion. Env is conformationally flexible but controls its transition from the unbound "closed" conformation (State 1) to downstream CD4-bound conformations (States 2/3), which are required for fusion. In particular, HIV-1 has evolved several mechanisms that reduce the premature "opening" of Env which exposes highly conserved epitopes recognized by non-neutralizing antibodies (nnAbs) capable of mediating antibody-dependent cellular cytotoxicity (ADCC). Env cleavage decreases its conformational transitions favoring the adoption of the "closed" conformation. Here we altered the gp160 furin cleavage site to impair Env cleavage and to examine its impact on ADCC responses mediated by plasma from HIV-1-infected individuals. We found that infected primary CD4+ T cells expressing uncleaved, but not wildtype, Env are efficiently recognized by nnAbs and become highly susceptible to ADCC responses mediated by plasma from HIV-1-infected individuals. Thus, HIV-1 limits the exposure of uncleaved Env at the surface of HIV-1-infected cells at least in part to escape ADCC responses.
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Affiliation(s)
- Jérémie Prévost
- Centre de Recherche du CHUM, Montreal, QC H2X 0A9, Canada; (J.P.); (H.M.); (D.V.)
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, QC H2X 0A9, Canada
| | - Halima Medjahed
- Centre de Recherche du CHUM, Montreal, QC H2X 0A9, Canada; (J.P.); (H.M.); (D.V.)
| | - Dani Vézina
- Centre de Recherche du CHUM, Montreal, QC H2X 0A9, Canada; (J.P.); (H.M.); (D.V.)
| | - Hung-Ching Chen
- Department of Chemistry, School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA 19104-6323, USA; (H.-C.C.); (A.B.S.III)
| | - Beatrice H. Hahn
- Departments of Medicine and Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6076, USA;
| | - Amos B. Smith
- Department of Chemistry, School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA 19104-6323, USA; (H.-C.C.); (A.B.S.III)
| | - Andrés Finzi
- Centre de Recherche du CHUM, Montreal, QC H2X 0A9, Canada; (J.P.); (H.M.); (D.V.)
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, QC H2X 0A9, Canada
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11
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McCaul N, Quandte M, Bontjer I, van Zadelhoff G, Land A, Crooks ET, Binley JM, Sanders RW, Braakman I. Intramolecular quality control: HIV-1 envelope gp160 signal-peptide cleavage as a functional folding checkpoint. Cell Rep 2021; 36:109646. [PMID: 34469718 DOI: 10.1016/j.celrep.2021.109646] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 06/28/2021] [Accepted: 08/11/2021] [Indexed: 11/24/2022] Open
Abstract
Removal of the membrane-tethering signal peptides that target secretory proteins to the endoplasmic reticulum is a prerequisite for proper folding. While generally thought to be removed co-translationally, we report two additional post-targeting functions for the HIV-1 gp120 signal peptide, which remains attached until gp120 folding triggers its removal. First, the signal peptide improves folding fidelity by enhancing conformational plasticity of gp120 by driving disulfide isomerization through a redox-active cysteine. Simultaneously, the signal peptide delays folding by tethering the N terminus to the membrane, until assembly with the C terminus. Second, its carefully timed cleavage represents intramolecular quality control and ensures release of (only) natively folded gp120. Postponed cleavage and the redox-active cysteine are both highly conserved and important for viral fitness. Considering the ∼15% proteins with signal peptides and the frequency of N-to-C contacts in protein structures, these regulatory roles of signal peptides are bound to be more common in secretory-protein biogenesis.
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Affiliation(s)
- Nicholas McCaul
- Cellular Protein Chemistry, Bijvoet Center for Biomolecular Research, Science4Life, Faculty of Science, Utrecht University, Padualaan 8, 3584 Utrecht, the Netherlands
| | - Matthias Quandte
- Cellular Protein Chemistry, Bijvoet Center for Biomolecular Research, Science4Life, Faculty of Science, Utrecht University, Padualaan 8, 3584 Utrecht, the Netherlands
| | - Ilja Bontjer
- Department of Medical Microbiology, Amsterdam UMC, University of Amsterdam, Amsterdam Institute for Infection and Immunity, 1105 Amsterdam, the Netherlands
| | - Guus van Zadelhoff
- Cellular Protein Chemistry, Bijvoet Center for Biomolecular Research, Science4Life, Faculty of Science, Utrecht University, Padualaan 8, 3584 Utrecht, the Netherlands
| | - Aafke Land
- Cellular Protein Chemistry, Bijvoet Center for Biomolecular Research, Science4Life, Faculty of Science, Utrecht University, Padualaan 8, 3584 Utrecht, the Netherlands
| | - Ema T Crooks
- San Diego Biomedical Research Institute, 10865 Road to the Cure #100, San Diego, CA, USA
| | - James M Binley
- San Diego Biomedical Research Institute, 10865 Road to the Cure #100, San Diego, CA, USA
| | - Rogier W Sanders
- Department of Medical Microbiology, Amsterdam UMC, University of Amsterdam, Amsterdam Institute for Infection and Immunity, 1105 Amsterdam, the Netherlands; Department of Microbiology and Immunology, Weill Medical College of Cornell University, New York, NY 10021, USA
| | - Ineke Braakman
- Cellular Protein Chemistry, Bijvoet Center for Biomolecular Research, Science4Life, Faculty of Science, Utrecht University, Padualaan 8, 3584 Utrecht, the Netherlands.
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12
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Ma H, Wang H, Li M, Barreto-de-Souza V, Reinecke BA, Gunta R, Zheng Y, Kang G, Nassehi N, Zhang H, An J, Selley DE, Hauser KF, Zhang Y. Bivalent Ligand Aiming Putative Mu Opioid Receptor and Chemokine Receptor CXCR4 Dimers in Opioid Enhanced HIV-1 Entry. ACS Med Chem Lett 2020; 11:2318-2324. [PMID: 33214847 PMCID: PMC7667867 DOI: 10.1021/acsmedchemlett.0c00444] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Accepted: 09/10/2020] [Indexed: 12/17/2022] Open
Abstract
A bivalent compound 1a featuring both a mu opioid receptor (MOR) and a CXCR4 antagonist pharmacophore (naltrexone and IT1t) was designed and synthesized. Further binding and functional studies demonstrated 1a acting as a MOR and a CXCR4 dual antagonist with reasonable binding affinities at both receptors. Furthermore, compound 1a seemed more effective than a combination of IT1t and naltrexone in inhibiting HIV entry at the presence of morphine. Additional molecular modeling results suggested that 1a may bind with the putative MOR-CXCR4 heterodimer to induce its anti-HIV activity. Collectively, bivalent ligand 1a may serve as a promising lead to develop chemical probes targeting the putative MOR-CXCR4 heterodimer in comprehending opioid exacerbated HIV-1 invasion.
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Affiliation(s)
- Hongguang Ma
- Department
of Medicinal Chemistry, School of Pharmacy, Virginia Commonwealth University, 800 E Leigh Street, Richmond, Virginia 23298, United States
| | - Huiqun Wang
- Department
of Medicinal Chemistry, School of Pharmacy, Virginia Commonwealth University, 800 E Leigh Street, Richmond, Virginia 23298, United States
| | - Mengchu Li
- Department
of Medicinal Chemistry, School of Pharmacy, Virginia Commonwealth University, 800 E Leigh Street, Richmond, Virginia 23298, United States
| | - Victor Barreto-de-Souza
- Department
of Pharmacology and Toxicology, Virginia
Commonwealth University, 410 North 12th Street, Richmond, Virginia 23298, United
States
| | - Bethany A. Reinecke
- Department
of Medicinal Chemistry, School of Pharmacy, Virginia Commonwealth University, 800 E Leigh Street, Richmond, Virginia 23298, United States
| | - Rama Gunta
- Department
of Medicinal Chemistry, School of Pharmacy, Virginia Commonwealth University, 800 E Leigh Street, Richmond, Virginia 23298, United States
| | - Yi Zheng
- Department
of Medicinal Chemistry, School of Pharmacy, Virginia Commonwealth University, 800 E Leigh Street, Richmond, Virginia 23298, United States
| | - Guifeng Kang
- Department
of Medicinal Chemistry, School of Pharmacy, Virginia Commonwealth University, 800 E Leigh Street, Richmond, Virginia 23298, United States
| | - Nima Nassehi
- Department
of Pharmacology and Toxicology, Virginia
Commonwealth University, 410 North 12th Street, Richmond, Virginia 23298, United
States
| | - Huijun Zhang
- Department
of Medicine, Division of Infectious Diseases, School of Medicine, University of California San Diego, 9500 Gilman Drive, Stein Clinical
Research Building, Suite 410, La Jolla, California 92093, United States
| | - Jing An
- Department
of Medicine, Division of Infectious Diseases, School of Medicine, University of California San Diego, 9500 Gilman Drive, Stein Clinical
Research Building, Suite 410, La Jolla, California 92093, United States
| | - Dana E. Selley
- Department
of Pharmacology and Toxicology, Virginia
Commonwealth University, 410 North 12th Street, Richmond, Virginia 23298, United
States
| | - Kurt F. Hauser
- Department
of Pharmacology and Toxicology, Virginia
Commonwealth University, 410 North 12th Street, Richmond, Virginia 23298, United
States
| | - Yan Zhang
- Department
of Medicinal Chemistry, School of Pharmacy, Virginia Commonwealth University, 800 E Leigh Street, Richmond, Virginia 23298, United States
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13
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Li Y, Deng L, Liang J, Dong GH, Xia YL, Fu YX, Liu SQ. Molecular dynamics simulations reveal distinct differences in conformational dynamics and thermodynamics between the unliganded and CD4-bound states of HIV-1 gp120. Phys Chem Chem Phys 2020; 22:5548-5560. [PMID: 32119016 DOI: 10.1039/c9cp06706j] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The entry of human immunodeficiency virus type I (HIV-1) into host cells is initiated by binding to the cell-surface receptor CD4, which induces a conformational transition of the envelope (Env) glycoprotein gp120 from the closed, unliganded state to the open, CD4-bound state. Despite many available structures in these two states, detailed aspects on the dynamics and thermodynamics of gp120 remain elusive. Here, we performed microsecond-scale (μs-scale) multiple-replica molecular dynamics (MD) simulations to explore the differences in the conformational dynamics, protein motions, and thermodynamics between the unliganded and CD4-bound/complexed forms of gp120. Comparative analyses of MD trajectories reveal that CD4 binding promotes the structural deviations/changes and conformational flexibility, loosens the structural packing, and complicates the molecular motions of gp120. Comparison of the constructed free energy landscapes (FELs) reveals that the CD4-complexed gp120 has more conformational substates, larger conformational entropy, and lower thermostability than the unliganded form. Therefore, the unliganded conformation represents a structurally and energetically stable "ground state" for the full-length gp120. The observed great increase in the mobility of V1/V2 and V3 along with their more versatile movement directions in the CD4-bound gp120 compared to the unliganded form suggests that their orientations with respect to each other and to the structural core determine the differences in the conformational dynamics and thermodynamics between the two gp120 forms. The results presented here provide a basis by which to better understand the functional and immunological properties of gp120 and, furthermore, to deploy appropriate strategies for the development of anti-HIV-1 drugs or vaccines.
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Affiliation(s)
- Yi Li
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan & School of Life Sciences, Yunnan University, Kunming 650091, China. and College of Mathematics and Computer Science, Dali University, Dali 671003, China
| | - Lei Deng
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan & School of Life Sciences, Yunnan University, Kunming 650091, China.
| | - Jing Liang
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan & School of Life Sciences, Yunnan University, Kunming 650091, China.
| | - Guang-Heng Dong
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan & School of Life Sciences, Yunnan University, Kunming 650091, China.
| | - Yuan-Ling Xia
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan & School of Life Sciences, Yunnan University, Kunming 650091, China.
| | - Yun-Xin Fu
- Human Genetics Center and Division of Biostatistics, School of Public Health, The University of Texas Health Science Center, Houston, USA.
| | - Shu-Qun Liu
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan & School of Life Sciences, Yunnan University, Kunming 650091, China.
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14
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Staubus AO, Alfadhli A, Barklis RL, Barklis E. Replication of HIV-1 envelope protein cytoplasmic domain variants in permissive and restrictive cells. Virology 2019; 538:1-10. [PMID: 31550607 DOI: 10.1016/j.virol.2019.09.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 09/13/2019] [Accepted: 09/17/2019] [Indexed: 01/01/2023]
Abstract
Wild type (WT) HIV-1 envelope (Env) protein cytoplasmic tails (CTs) appear to be composed of membrane-proximal, N-terminal unstructured regions, and three C-terminal amphipathic helices. Previous studies have shown that WT and CT-deleted (ΔCT) Env proteins are incorporated into virus particles via different mechanisms. WT Env proteins traffic to cell plasma membranes (PMs), are rapidly internalized, recycle to PMs, and are incorporated into virions in permissive and restrictive cells in a Gag matrix (MA) protein-dependent fashion. In contrast, previously described ΔCT proteins do not appear to be internalized after their arrival to PMs, and do not require MA, but are only incorporated into virions in permissive cell lines. We have analyzed a new set of HIV-1 CT variants with respect to their replication in permissive and restrictive cells. Our results provide novel details as to how CT elements regulate HIV-1 Env protein function.
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Affiliation(s)
- August O Staubus
- Department of Molecular Microbiology and Immunology, Oregon Health and Sciences University, 3181 SW Sam Jackson Park Road, Portland, OR, 97239, USA
| | - Ayna Alfadhli
- Department of Molecular Microbiology and Immunology, Oregon Health and Sciences University, 3181 SW Sam Jackson Park Road, Portland, OR, 97239, USA
| | - Robin Lid Barklis
- Department of Molecular Microbiology and Immunology, Oregon Health and Sciences University, 3181 SW Sam Jackson Park Road, Portland, OR, 97239, USA
| | - Eric Barklis
- Department of Molecular Microbiology and Immunology, Oregon Health and Sciences University, 3181 SW Sam Jackson Park Road, Portland, OR, 97239, USA.
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15
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Behren S, Westerlind U. Glycopeptides and -Mimetics to Detect, Monitor and Inhibit Bacterial and Viral Infections: Recent Advances and Perspectives. Molecules 2019; 24:E1004. [PMID: 30871155 PMCID: PMC6471658 DOI: 10.3390/molecules24061004] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 03/06/2019] [Accepted: 03/07/2019] [Indexed: 11/17/2022] Open
Abstract
The initial contact of pathogens with host cells is usually mediated by their adhesion to glycan structures present on the cell surface in order to enable infection. Furthermore, glycans play important roles in the modulation of the host immune responses to infection. Understanding the carbohydrate-pathogen interactions are of importance for the development of novel and efficient strategies to either prevent, or interfere with pathogenic infection. Synthetic glycopeptides and mimetics thereof are capable of imitating the multivalent display of carbohydrates at the cell surface, which have become an important objective of research over the last decade. Glycopeptide based constructs may function as vaccines or anti-adhesive agents that interfere with the ability of pathogens to adhere to the host cell glycans and thus possess the potential to improve or replace treatments that suffer from resistance. Additionally, synthetic glycopeptides are used as tools for epitope mapping of antibodies directed against structures present on various pathogens and have become important to improve serodiagnostic methods and to develop novel epitope-based vaccines. This review will provide an overview of the most recent advances in the synthesis and application of glycopeptides and glycopeptide mimetics exhibiting a peptide-like backbone in glycobiology.
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Affiliation(s)
- Sandra Behren
- Department of Chemistry, Umeå University, 90187 Umeå, Sweden.
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16
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Li T, Zhang Z, Zhang Z, Qiao J, Rong R, Zhang Y, Yao Q, Li Z, Shen H, Huang F, Xue W, Gao S, Li S, Zheng Q, Yu H, Zhang J, Gu Y, Li S, Xia N. Characterization of native-like HIV-1 gp140 glycoprotein expressed in insect cells. Vaccine 2019; 37:1418-1427. [PMID: 30737044 DOI: 10.1016/j.vaccine.2019.01.048] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Revised: 01/15/2019] [Accepted: 01/28/2019] [Indexed: 11/25/2022]
Abstract
The trimeric HIV-1 envelope glycoprotein (Env) is critical for vaccine development aimed at achieving broadly-neutralizing antibody responses. The use of various recombinant expression systems and construct designs are associated with the resultant nature of produced proteins, especially in terms of glycosylation, antigenicity, and immunogenicity of the glycoprotein. Here, we explored an otherwise baculovirus cassette than classical one designed to express HIV-1 Env protein, including SOSIP mutation and Foldon moiety involvement. This improved design increased the ratio of the Env trimer fraction from ∼40% to ∼60% with respect to that of prototypical design, as indicated by high-performance size-exclusion chromatography and sedimentation velocity analysis. In addition, the design prolonged cell viability and enhanced the final yield (approximately 13-15 mg/L) after affinity purification. gp140 produced from insect cells mimicked the native-like trimer and mainly adopted glycosylation pattern of oligomannose glycans. The native-like Env proteins conferred cross-clade neutralizing antibody production in BALB/c mice. In summary, the expression of Env in insect cells by optimizing the baculovirus vector provides an alternative strategy for HIV-1 immunogen production and may benefit future Env-based HIV vaccine design.
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Affiliation(s)
- Tingting Li
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Life Sciences, Xiamen University, Xiamen 361102, China
| | - Zhenyong Zhang
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Life Sciences, Xiamen University, Xiamen 361102, China
| | - Zhiqing Zhang
- National Institute of Diagnostics and Vaccine Development in Infectious Disease, School of Public Health, Xiamen University, Xiamen 361102, China
| | - Jiaming Qiao
- National Institute of Diagnostics and Vaccine Development in Infectious Disease, School of Public Health, Xiamen University, Xiamen 361102, China
| | - Rui Rong
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Life Sciences, Xiamen University, Xiamen 361102, China
| | - Yuyun Zhang
- National Institute of Diagnostics and Vaccine Development in Infectious Disease, School of Public Health, Xiamen University, Xiamen 361102, China
| | - Qiaobin Yao
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Life Sciences, Xiamen University, Xiamen 361102, China
| | - Zekai Li
- National Institute of Diagnostics and Vaccine Development in Infectious Disease, School of Public Health, Xiamen University, Xiamen 361102, China
| | - Honglin Shen
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Life Sciences, Xiamen University, Xiamen 361102, China
| | - Fang Huang
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Life Sciences, Xiamen University, Xiamen 361102, China
| | - Wenhui Xue
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Life Sciences, Xiamen University, Xiamen 361102, China
| | - Shuangquan Gao
- National Institute of Diagnostics and Vaccine Development in Infectious Disease, School of Public Health, Xiamen University, Xiamen 361102, China
| | - Shaoyong Li
- National Institute of Diagnostics and Vaccine Development in Infectious Disease, School of Public Health, Xiamen University, Xiamen 361102, China
| | - Qingbing Zheng
- National Institute of Diagnostics and Vaccine Development in Infectious Disease, School of Public Health, Xiamen University, Xiamen 361102, China
| | - Hai Yu
- National Institute of Diagnostics and Vaccine Development in Infectious Disease, School of Public Health, Xiamen University, Xiamen 361102, China
| | - Jun Zhang
- National Institute of Diagnostics and Vaccine Development in Infectious Disease, School of Public Health, Xiamen University, Xiamen 361102, China
| | - Ying Gu
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Life Sciences, Xiamen University, Xiamen 361102, China; National Institute of Diagnostics and Vaccine Development in Infectious Disease, School of Public Health, Xiamen University, Xiamen 361102, China.
| | - Shaowei Li
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Life Sciences, Xiamen University, Xiamen 361102, China; National Institute of Diagnostics and Vaccine Development in Infectious Disease, School of Public Health, Xiamen University, Xiamen 361102, China.
| | - Ningshao Xia
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Life Sciences, Xiamen University, Xiamen 361102, China; National Institute of Diagnostics and Vaccine Development in Infectious Disease, School of Public Health, Xiamen University, Xiamen 361102, China
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17
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Bagdonaite I, Vakhrushev SY, Joshi HJ, Wandall HH. Viral glycoproteomes: technologies for characterization and outlook for vaccine design. FEBS Lett 2018; 592:3898-3920. [PMID: 29961944 DOI: 10.1002/1873-3468.13177] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Revised: 06/13/2018] [Accepted: 06/26/2018] [Indexed: 12/27/2022]
Abstract
It has long been known that surface proteins of most enveloped viruses are covered with glycans. It has furthermore been demonstrated that glycosylation is essential for propagation and immune evasion for many viruses. The recent development of high-resolution mass spectrometry techniques has enabled identification not only of the precise structures but also the positions of such post-translational modifications on viruses, revealing substantial differences in extent of glycosylation and glycan maturation for different classes of viruses. In-depth characterization of glycosylation and other post-translational modifications of viral envelope glycoproteins is essential for rational design of vaccines and antivirals. In this Review, we provide an overview of techniques used to address viral glycosylation and summarize information on glycosylation of enveloped viruses representing ongoing public health challenges. Furthermore, we discuss how knowledge on glycosylation can be translated to means to prevent and combat viral infections.
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Affiliation(s)
- Ieva Bagdonaite
- Department of Cellular and Molecular Medicine, Copenhagen Center for Glycomics, University of Copenhagen, Denmark
| | - Sergey Y Vakhrushev
- Department of Cellular and Molecular Medicine, Copenhagen Center for Glycomics, University of Copenhagen, Denmark
| | - Hiren J Joshi
- Department of Cellular and Molecular Medicine, Copenhagen Center for Glycomics, University of Copenhagen, Denmark
| | - Hans H Wandall
- Department of Cellular and Molecular Medicine, Copenhagen Center for Glycomics, University of Copenhagen, Denmark
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18
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HIV-1 Envelope Glycoprotein Trafficking through the Endosomal Recycling Compartment Is Required for Particle Incorporation. J Virol 2018; 92:JVI.01893-17. [PMID: 29212940 DOI: 10.1128/jvi.01893-17] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Accepted: 11/22/2017] [Indexed: 01/31/2023] Open
Abstract
The human immunodeficiency virus type 1 (HIV-1) envelope glycoprotein (Env) encodes specific trafficking signals within its long cytoplasmic tail (CT) that regulate incorporation into HIV-1 particles. Rab11-family interacting protein 1C (FIP1C) and Rab14 are host trafficking factors required for Env particle incorporation, suggesting that Env undergoes sorting from the endosomal recycling compartment (ERC) to the site of particle assembly on the plasma membrane. We disrupted outward sorting from the ERC by expressing a C-terminal fragment of FIP1C (FIP1C560-649) and examined the consequences on Env trafficking and incorporation into particles. FIP1C560-649 reduced cell surface levels of Env and prevented its incorporation into HIV-1 particles. Remarkably, Env was trapped in an exaggerated perinuclear ERC in a CT-dependent manner. Mutation of either the Yxxϕ endocytic motif or the YW795 motif in the CT prevented Env trapping in the ERC and restored incorporation into particles. In contrast, simian immunodeficiency virus SIVmac239 Env was not retained in the ERC, while substitution of the HIV-1 CT for the SIV CT resulted in SIV Env retention in this compartment. These results provide the first direct evidence that Env traffics through the ERC and support a model whereby HIV-1 Env is specifically targeted to the ERC prior to FIP1C- and CT-dependent outward sorting to the particle assembly site on the plasma membrane.IMPORTANCE The HIV envelope protein is an essential component of the viral particle. While many aspects of envelope protein structure and function have been established, the pathway it follows in the cell prior to reaching the site of particle assembly is not well understood. The envelope protein has a very long cytoplasmic tail that interacts with the host cell trafficking machinery. Here, we utilized a truncated form of the trafficking adaptor FIP1C protein to arrest the intracellular transport of the envelope protein, demonstrating that it becomes trapped inside the cell within the endosomal recycling compartment. Intracellular trapping resulted in a loss of envelope protein on released particles and a corresponding loss of infectivity. Mutations of specific trafficking motifs in the envelope protein tail prevented its trapping in the recycling compartment. These results establish that trafficking to the endosomal recycling compartment is an essential step in HIV envelope protein particle incorporation.
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19
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Snapp EL, McCaul N, Quandte M, Cabartova Z, Bontjer I, Källgren C, Nilsson I, Land A, von Heijne G, Sanders RW, Braakman I. Structure and topology around the cleavage site regulate post-translational cleavage of the HIV-1 gp160 signal peptide. eLife 2017; 6:26067. [PMID: 28753126 PMCID: PMC5577925 DOI: 10.7554/elife.26067] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Accepted: 07/26/2017] [Indexed: 12/29/2022] Open
Abstract
Like all other secretory proteins, the HIV-1 envelope glycoprotein gp160 is targeted to the endoplasmic reticulum (ER) by its signal peptide during synthesis. Proper gp160 folding in the ER requires core glycosylation, disulfide-bond formation and proline isomerization. Signal-peptide cleavage occurs only late after gp160 chain termination and is dependent on folding of the soluble subunit gp120 to a near-native conformation. We here detail the mechanism by which co-translational signal-peptide cleavage is prevented. Conserved residues from the signal peptide and residues downstream of the canonical cleavage site form an extended alpha-helix in the ER membrane, which covers the cleavage site, thus preventing cleavage. A point mutation in the signal peptide breaks the alpha helix allowing co-translational cleavage. We demonstrate that postponed cleavage of gp160 enhances functional folding of the molecule. The change to early cleavage results in decreased viral fitness compared to wild-type HIV.
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Affiliation(s)
- Erik Lee Snapp
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Nicholas McCaul
- Cellular Protein Chemistry, Bijvoet Center for Biomolecular Research, Faculty of Science, Utrecht University, Utrecht, Netherlands
| | - Matthias Quandte
- Cellular Protein Chemistry, Bijvoet Center for Biomolecular Research, Faculty of Science, Utrecht University, Utrecht, Netherlands
| | - Zuzana Cabartova
- National Institute of Public Health, National Reference Laboratory for Viral Hepatitis, Prague, Czech Republic
| | - Ilja Bontjer
- Department of Medical Microbiology, Laboratory of Experimental Virology, Center for Infection and Immunity Amsterdam, Academic Medical Center, Amsterdam, Netherlands
| | - Carolina Källgren
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden.,Science for Life Laboratory, Stockholm University, Solna, Sweden
| | - IngMarie Nilsson
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden.,Science for Life Laboratory, Stockholm University, Solna, Sweden
| | - Aafke Land
- Cellular Protein Chemistry, Bijvoet Center for Biomolecular Research, Faculty of Science, Utrecht University, Utrecht, Netherlands
| | - Gunnar von Heijne
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden.,Science for Life Laboratory, Stockholm University, Solna, Sweden
| | - Rogier W Sanders
- Department of Medical Microbiology, Laboratory of Experimental Virology, Center for Infection and Immunity Amsterdam, Academic Medical Center, Amsterdam, Netherlands
| | - Ineke Braakman
- Cellular Protein Chemistry, Bijvoet Center for Biomolecular Research, Faculty of Science, Utrecht University, Utrecht, Netherlands
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20
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Mitchell CA, Ramessar K, O'Keefe BR. Antiviral lectins: Selective inhibitors of viral entry. Antiviral Res 2017; 142:37-54. [PMID: 28322922 PMCID: PMC5414728 DOI: 10.1016/j.antiviral.2017.03.007] [Citation(s) in RCA: 107] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Accepted: 03/13/2017] [Indexed: 01/27/2023]
Abstract
Many natural lectins have been reported to have antiviral activity. As some of these have been put forward as potential development candidates for preventing or treating viral infections, we have set out in this review to survey the literature on antiviral lectins. The review groups lectins by structural class and class of source organism we also detail their carbohydrate specificity and their reported antiviral activities. The review concludes with a brief discussion of several of the pertinent hurdles that heterologous proteins must clear to be useful clinical candidates and cites examples where such studies have been reported for antiviral lectins. Though the clearest path currently being followed is the use of antiviral lectins as anti-HIV microbicides via topical mucosal administration, some investigators have also found systemic efficacy against acute infections following subcutaneous administration.
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Affiliation(s)
- Carter A Mitchell
- Molecular Targets Laboratory, Center for Cancer Research, National Cancer Institute, NIH, Frederick, MD, 21702-1201, USA
| | - Koreen Ramessar
- Molecular Targets Laboratory, Center for Cancer Research, National Cancer Institute, NIH, Frederick, MD, 21702-1201, USA
| | - Barry R O'Keefe
- Molecular Targets Laboratory, Center for Cancer Research, National Cancer Institute, NIH, Frederick, MD, 21702-1201, USA.
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21
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Duan LW, Zhang H, Zhao MT, Sun JX, Chen WL, Lin JP, Liu XQ. A non-canonical binding interface in the crystal structure of HIV-1 gp120 core in complex with CD4. Sci Rep 2017; 7:46733. [PMID: 28429756 PMCID: PMC5399459 DOI: 10.1038/srep46733] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Accepted: 03/24/2017] [Indexed: 01/25/2023] Open
Abstract
Numerous crystal structures of HIV gp120 have been reported, alone or with receptor CD4 and cognate antibodies; however, no sole gp120/CD4 complex without stabilization by an antibody is available. Here, we report a crystal structure of the gp120/CD4 complex without the aid of an antibody from HIV-1 CRF07_BC, a strain circulating in China. Interestingly, in addition to the canonical binding surface, a second interacting interface was identified. A mutagenesis study on critical residues revealed that the stability of this interface is important for the efficiency of Env-mediated membrane fusion. Furthermore, we found that a broad neutralizing antibody, ibalizumab, which targets CD4 in the absence of gp120, occupies the same binding surface as the second interface identified here on gp120. Therefore, we identified the possibility of the involvement of a second gp120-CD4 interaction interface during viral entry, and also provided a reasonable explanation for the broad activity of neutralizing antibody ibalizumab.
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Affiliation(s)
- Liang-Wei Duan
- State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences, Nankai University, Tianjin 300071, China
- Research Center for Immunology, School of Laboratory Medicine, Henan Collaborative Innovation Center of Molecular Diagnosis and Laboratory Medicine, Xinxiang Medical University, Xinxiang 453000, China
| | - Hui Zhang
- State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Meng-Ting Zhao
- State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Ji-Xue Sun
- State Key Laboratory of Medicinal Chemical Biology, College of Pharmacy, Nankai University, Tianjin 300071, China
| | - Wen-Li Chen
- State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Jian-Ping Lin
- State Key Laboratory of Medicinal Chemical Biology, College of Pharmacy, Nankai University, Tianjin 300071, China
| | - Xin-Qi Liu
- State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences, Nankai University, Tianjin 300071, China
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22
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Behrens AJ, Seabright GE, Crispin M. Targeting Glycans of HIV Envelope Glycoproteins for Vaccine Design. CHEMICAL BIOLOGY OF GLYCOPROTEINS 2017. [DOI: 10.1039/9781782623823-00300] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The surface of the envelope spike of the human immunodeficiency virus (HIV) is covered with a dense array of glycans, which is sufficient to impede the host antibody response while maintaining a window for receptor recognition. The glycan density significantly exceeds that typically observed on self glycoproteins and is sufficiently high to disrupt the maturation process of glycans, from oligomannose- to complex-type glycosylation, that normally occurs during glycoprotein transit through the secretory system. It is notable that this generates a degree of homogeneity not seen in the highly mutated protein moiety. The conserved, close glycan packing and divergences from default glycan processing give a window for immune recognition. Encouragingly, in a subset of individuals, broadly neutralizing antibodies (bNAbs) have been isolated that recognize these features and are protective in passive-transfer models. Here, we review the recent advances in our understanding of the glycan shield of HIV and outline the strategies that are being pursued to elicit glycan-binding bNAbs by vaccination.
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Affiliation(s)
- Anna-Janina Behrens
- Oxford Glycobiology Institute, Department of Biochemistry, University of Oxford South Parks Road Oxford OX1 3QU UK
| | - Gemma E. Seabright
- Oxford Glycobiology Institute, Department of Biochemistry, University of Oxford South Parks Road Oxford OX1 3QU UK
| | - Max Crispin
- Oxford Glycobiology Institute, Department of Biochemistry, University of Oxford South Parks Road Oxford OX1 3QU UK
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23
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Wibmer CK, Gorman J, Ozorowski G, Bhiman JN, Sheward DJ, Elliott DH, Rouelle J, Smira A, Joyce MG, Ndabambi N, Druz A, Asokan M, Burton DR, Connors M, Abdool Karim SS, Mascola JR, Robinson JE, Ward AB, Williamson C, Kwong PD, Morris L, Moore PL. Structure and Recognition of a Novel HIV-1 gp120-gp41 Interface Antibody that Caused MPER Exposure through Viral Escape. PLoS Pathog 2017; 13:e1006074. [PMID: 28076415 PMCID: PMC5226681 DOI: 10.1371/journal.ppat.1006074] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Accepted: 11/17/2016] [Indexed: 12/15/2022] Open
Abstract
A comprehensive understanding of the regions on HIV-1 envelope trimers targeted by broadly neutralizing antibodies may contribute to rational design of an HIV-1 vaccine. We previously identified a participant in the CAPRISA cohort, CAP248, who developed trimer-specific antibodies capable of neutralizing 60% of heterologous viruses at three years post-infection. Here, we report the isolation by B cell culture of monoclonal antibody CAP248-2B, which targets a novel membrane proximal epitope including elements of gp120 and gp41. Despite low maximum inhibition plateaus, often below 50% inhibitory concentrations, the breadth of CAP248-2B significantly correlated with donor plasma. Site-directed mutagenesis, X-ray crystallography, and negative-stain electron microscopy 3D reconstructions revealed how CAP248-2B recognizes a cleavage-dependent epitope that includes the gp120 C terminus. While this epitope is distinct, it overlapped in parts of gp41 with the epitopes of broadly neutralizing antibodies PGT151, VRC34, 35O22, 3BC315, and 10E8. CAP248-2B has a conformationally variable paratope with an unusually long 19 amino acid light chain third complementarity determining region. Two phenylalanines at the loop apex were predicted by docking and mutagenesis data to interact with the viral membrane. Neutralization by CAP248-2B is not dependent on any single glycan proximal to its epitope, and low neutralization plateaus could not be completely explained by N- or O-linked glycosylation pathway inhibitors, furin co-transfection, or pre-incubation with soluble CD4. Viral escape from CAP248-2B involved a cluster of rare mutations in the gp120-gp41 cleavage sites. Simultaneous introduction of these mutations into heterologous viruses abrogated neutralization by CAP248-2B, but enhanced neutralization sensitivity to 35O22, 4E10, and 10E8 by 10-100-fold. Altogether, this study expands the region of the HIV-1 gp120-gp41 quaternary interface that is a target for broadly neutralizing antibodies and identifies a set of mutations in the gp120 C terminus that exposes the membrane-proximal external region of gp41, with potential utility in HIV vaccine design.
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Affiliation(s)
- Constantinos Kurt Wibmer
- Centre for HIV and STIs, National Institute for Communicable Diseases (NICD), of the National Health Laboratory Service (NHLS), Johannesburg, South Africa
- Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Jason Gorman
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Gabriel Ozorowski
- Department of Integrative Structural and Computational Biology, CHAVI-ID, IAVI Neutralizing Antibody Center and Collaboration for AIDS Vaccine Discovery (CAVD), The Scripps Research Institute, La Jolla, California, United States of America
| | - Jinal N. Bhiman
- Centre for HIV and STIs, National Institute for Communicable Diseases (NICD), of the National Health Laboratory Service (NHLS), Johannesburg, South Africa
- Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Daniel J. Sheward
- Institute of Infectious Disease and Molecular Medicine (IDM) and Division of Medical Virology, University of Cape Town and NHLS, Cape Town, South Africa
| | - Debra H. Elliott
- Department of Pediatrics, Tulane University Medical Center, New Orleans, Louisiana, United States of America
| | - Julie Rouelle
- Department of Pediatrics, Tulane University Medical Center, New Orleans, Louisiana, United States of America
| | - Ashley Smira
- Department of Pediatrics, Tulane University Medical Center, New Orleans, Louisiana, United States of America
| | - M. Gordon Joyce
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Nonkululeko Ndabambi
- Institute of Infectious Disease and Molecular Medicine (IDM) and Division of Medical Virology, University of Cape Town and NHLS, Cape Town, South Africa
| | - Aliaksandr Druz
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Mangai Asokan
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Dennis R. Burton
- Department of Immunology and Microbial Science, CHAVI-ID and IAVI Neutralizing Antibody Centre, The Scripps Research Institute, La Jolla, California, United States of America
- Ragon Institute of Massachusetts General Hospital, MIT and Harvard, Cambridge, Massachusetts, United States of America
| | - Mark Connors
- Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Salim S. Abdool Karim
- Centre for the AIDS Programme of Research in South Africa (CAPRISA), University of KwaZulu-Natal, Durban, South Africa
- Department of Epidemiology, Columbia University, New York, New York, United States of America
| | - John R. Mascola
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - James E. Robinson
- Department of Pediatrics, Tulane University Medical Center, New Orleans, Louisiana, United States of America
| | - Andrew B. Ward
- Department of Integrative Structural and Computational Biology, CHAVI-ID, IAVI Neutralizing Antibody Center and Collaboration for AIDS Vaccine Discovery (CAVD), The Scripps Research Institute, La Jolla, California, United States of America
| | - Carolyn Williamson
- Institute of Infectious Disease and Molecular Medicine (IDM) and Division of Medical Virology, University of Cape Town and NHLS, Cape Town, South Africa
- Centre for the AIDS Programme of Research in South Africa (CAPRISA), University of KwaZulu-Natal, Durban, South Africa
| | - Peter D. Kwong
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Lynn Morris
- Centre for HIV and STIs, National Institute for Communicable Diseases (NICD), of the National Health Laboratory Service (NHLS), Johannesburg, South Africa
- Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
- Centre for the AIDS Programme of Research in South Africa (CAPRISA), University of KwaZulu-Natal, Durban, South Africa
| | - Penny L. Moore
- Centre for HIV and STIs, National Institute for Communicable Diseases (NICD), of the National Health Laboratory Service (NHLS), Johannesburg, South Africa
- Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
- Centre for the AIDS Programme of Research in South Africa (CAPRISA), University of KwaZulu-Natal, Durban, South Africa
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24
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Heaton NS, Moshkina N, Fenouil R, Gardner TJ, Aguirre S, Shah PS, Zhao N, Manganaro L, Hultquist JF, Noel J, Sachs D, Hamilton J, Leon PE, Chawdury A, Tripathi S, Melegari C, Campisi L, Hai R, Metreveli G, Gamarnik AV, García-Sastre A, Greenbaum B, Simon V, Fernandez-Sesma A, Krogan NJ, Mulder LCF, van Bakel H, Tortorella D, Taunton J, Palese P, Marazzi I. Targeting Viral Proteostasis Limits Influenza Virus, HIV, and Dengue Virus Infection. Immunity 2016; 44:46-58. [PMID: 26789921 DOI: 10.1016/j.immuni.2015.12.017] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Revised: 10/26/2015] [Accepted: 10/28/2015] [Indexed: 12/22/2022]
Abstract
Viruses are obligate parasites and thus require the machinery of the host cell to replicate. Inhibition of host factors co-opted during active infection is a strategy hosts use to suppress viral replication and a potential pan-antiviral therapy. To define the cellular proteins and processes required for a virus during infection is thus crucial to understanding the mechanisms of virally induced disease. In this report, we generated fully infectious tagged influenza viruses and used infection-based proteomics to identify pivotal arms of cellular signaling required for influenza virus growth and infectivity. Using mathematical modeling and genetic and pharmacologic approaches, we revealed that modulation of Sec61-mediated cotranslational translocation selectively impaired glycoprotein proteostasis of influenza as well as HIV and dengue viruses and led to inhibition of viral growth and infectivity. Thus, by studying virus-human protein-protein interactions in the context of active replication, we have identified targetable host factors for broad-spectrum antiviral therapies.
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Affiliation(s)
- Nicholas S Heaton
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Natasha Moshkina
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA; Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Romain Fenouil
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Thomas J Gardner
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Sebastian Aguirre
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Priya S Shah
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158-2140, USA
| | - Nan Zhao
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA; Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Lara Manganaro
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Judd F Hultquist
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158-2140, USA
| | - Justine Noel
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA; Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - David Sachs
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Jennifer Hamilton
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Paul E Leon
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Amit Chawdury
- Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA; Division of Hematology and Oncology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA; Department of Pathology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Shashank Tripathi
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Camilla Melegari
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA; Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Laura Campisi
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA; Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Rong Hai
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Giorgi Metreveli
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA; Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Andrea V Gamarnik
- Fundación Instituto Leloir-CONICET, Avenida Patricias Argentinas 435, Buenos Aires 1405, Argentina
| | - Adolfo García-Sastre
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA; Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA; Division of Infectious Diseases, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Benjamin Greenbaum
- Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA; Division of Hematology and Oncology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA; Department of Pathology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Viviana Simon
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA; Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Ana Fernandez-Sesma
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA; Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Nevan J Krogan
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158-2140, USA
| | - Lubbertus C F Mulder
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA; Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Harm van Bakel
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Domenico Tortorella
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Jack Taunton
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158-2140, USA
| | - Peter Palese
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Ivan Marazzi
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA; Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA.
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25
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Range of CD4-Bound Conformations of HIV-1 gp120, as Defined Using Conditional CD4-Induced Antibodies. J Virol 2016; 90:4481-4493. [PMID: 26889042 DOI: 10.1128/jvi.03206-15] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 02/14/2016] [Indexed: 01/23/2023] Open
Abstract
UNLABELLED The HIV envelope binds cellular CD4 and undergoes a range of conformational changes that lead to membrane fusion and delivery of the viral nucleocapsid into the cellular cytoplasm. This binding to CD4 reveals cryptic and highly conserved epitopes, the molecular nature of which is still not fully understood. The atomic structures of CD4 complexed with gp120 core molecules (a form of gp120 in which the V1, V2, and V3 loops and N and C termini have been truncated) have indicated that a hallmark feature of the CD4-bound conformation is the bridging sheet minidomain. Variations in the orientation of the bridging sheet hairpins have been revealed when CD4-liganded gp120 was compared to CD4-unliganded trimeric envelope structures. Hence, there appears to be a number of conformational transitions possible in HIV-1 monomeric gp120 that are affected by CD4 binding. The spectrum of CD4-bound conformations has been interrogated in this study by using a well-characterized panel of conditional, CD4-induced (CD4i) monoclonal antibodies (MAbs) that bind HIV-1 gp120 and its mutations under various conditions. Two distinct CD4i epitopes of the outer domain were studied: the first comprises the bridging sheet, while the second contains elements of the V2 loop. Furthermore, we show that the unliganded extended monomeric core of gp120 (coree) assumes an intermediate CD4i conformation in solution that further undergoes detectable rearrangements upon association with CD4. These discoveries impact both accepted paradigms concerning gp120 structure and the field of HIV immunogen design. IMPORTANCE Elucidation of the conformational transitions that the HIV-1 envelope protein undergoes during the course of entry into CD4(+)cells is fundamental to our understanding of HIV biology. The binding of CD4 triggers a range of gp120 structural rearrangements that could present targets for future drug design and development of preventive vaccines. Here we have systematically interrogated and scrutinized these conformational transitions using a panel of antibody probes that share a specific preference for the CD4i conformations. These have been employed to study a collection of gp120 mutations and truncations. Through these analyses, we propose 4 distinct sequential steps in CD4i transitions of gp120 conformations, each defined by antibody specificities and structural requirements of the HIV envelope monomer. As a result, we not only provide new insights into this dynamic process but also define probes to further investigate HIV infection.
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26
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Purification and functional reconstitution of human olfactory receptor expressed in Escherichia coli. BIOTECHNOL BIOPROC E 2015. [DOI: 10.1007/s12257-014-0897-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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27
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Coutu M, Finzi A. HIV-1 gp120 dimers decrease the overall affinity of gp120 preparations for CD4-induced ligands. J Virol Methods 2015; 215-216:37-44. [PMID: 25712564 DOI: 10.1016/j.jviromet.2015.02.017] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Revised: 02/11/2015] [Accepted: 02/15/2015] [Indexed: 11/19/2022]
Abstract
For several years, tools to study the conformational changes of HIV-1 envelope glycoproteins have been developed in order to comprehend those changes and their role in the fusion process and immunogenicity of HIV-1. To facilitate these studies, expression of the HIV-1 gp120 envelope glycoprotein has been done in several over-expression settings. However, over-expression of HIV-1 gp120 in mammalian cells leads to the formation of aberrant disulfide-linked dimers that can bias the results of experiments aimed at measuring gp120 affinity with different ligands. The presence of these gp120 dimers, generated in a widely used gp120 expression system, affects the affinity of gp120 for CD4-induced ligands, as evaluated by surface plasmon resonance. Upon monomeric gp120 purification, neither the removal of potential glycosylation sites on V4 nor the removal of the V5 variable region affect the overall affinity of gp120 for 17b and A32 CD4-induced ligands. Removal of these aberrant disulfide-linked gp120 dimers by standard size exclusion chromatography is sufficient to restore the overall affinity of gp120 preparations for these ligands.
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Affiliation(s)
- Mathieu Coutu
- Centre de Recherche du CHUM, Université de Montréal, Montreal, Quebec, Canada; Department of Microbiology, Infectiology and Immunology, Université de Montréal, Montreal, Quebec, Canada
| | - Andrés Finzi
- Centre de Recherche du CHUM, Université de Montréal, Montreal, Quebec, Canada; Department of Microbiology, Infectiology and Immunology, Université de Montréal, Montreal, Quebec, Canada; Department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada.
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28
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Horiya S, MacPherson IS, Krauss IJ. Recent strategies targeting HIV glycans in vaccine design. Nat Chem Biol 2014; 10:990-9. [PMID: 25393493 PMCID: PMC4431543 DOI: 10.1038/nchembio.1685] [Citation(s) in RCA: 85] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Accepted: 10/03/2014] [Indexed: 12/20/2022]
Abstract
Although efforts to develop a vaccine against HIV have so far met with little success, recent studies of HIV-positive patients with strongly neutralizing sera have shown that the human immune system is capable of producing potent and broadly neutralizing antibodies (bnAbs), some of which neutralize up to 90% of HIV strains. These antibodies bind conserved vulnerable sites on the viral envelope glycoprotein gp120, and identification of these sites has provided exciting clues about the design of potentially effective vaccines. Carbohydrates have a key role in this field, as a large fraction of bnAbs bind carbohydrates or combinations of carbohydrate and peptide elements on gp120. Additionally, carbohydrates partially mask some peptide surfaces recognized by bnAbs. The use of engineered glycoproteins and other glycostructures as vaccines to elicit antibodies with broad neutralizing activity is therefore a key area of interest in HIV vaccine design.
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Affiliation(s)
- Satoru Horiya
- Department of Chemistry, Brandeis University, Waltham, Massachusetts, USA
| | - Iain S MacPherson
- Department of Chemistry, Brandeis University, Waltham, Massachusetts, USA
| | - Isaac J Krauss
- Department of Chemistry, Brandeis University, Waltham, Massachusetts, USA
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29
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Lorenz IC, Nguyen HT, Kemelman M, Lindsay RW, Yuan M, Wright KJ, Arendt H, Back JW, DeStefano J, Hoffenberg S, Morrow G, Jurgens CK, Phogat SK, Zamb TJ, Parks CL. The stem of vesicular stomatitis virus G can be replaced with the HIV-1 Env membrane-proximal external region without loss of G function or membrane-proximal external region antigenic properties. AIDS Res Hum Retroviruses 2014; 30:1130-44. [PMID: 24597516 DOI: 10.1089/aid.2013.0206] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The structure of the HIV-1 envelope membrane-proximal external region (MPER) is influenced by its association with the lipid bilayer on the surface of virus particles and infected cells. To develop a replicating vaccine vector displaying MPER sequences in association with membrane, Env epitopes recognized by the broadly neutralizing antibodies 2F5, 4E10, or both were grafted into the membrane-proximal stem region of the vesicular stomatitis virus (VSV) glycoprotein (G). VSV encoding functional G-MPER chimeras based on G from the Indiana or New Jersey serotype propagated efficiently, although grafting of both epitopes (G-2F5-4E10) modestly reduced replication and resulted in the acquisition of one to two adaptive mutations in the grafted MPER sequence. Monoclonal antibodies 2F5 and 4E10 efficiently neutralized VSV G-MPER vectors and bound to virus particles in solution, indicating that the epitopes were accessible in the preattachment form of the G-MPER chimeras. Overall, our results showed that the HIV Env MPER could functionally substitute for the VSV G-stem region implying that both perform similar functions even though they are from unrelated viruses. Furthermore, we found that the MPER sequence grafts induced low but detectable MPER-specific antibody responses in rabbits vaccinated with live VSV, although additional vector and immunogen modifications or use of a heterologous prime-boost vaccination regimen will be required to increase the magnitude of the immune response.
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Affiliation(s)
- Ivo C. Lorenz
- The International AIDS Vaccine Initiative, AIDS Vaccine Design and Development Laboratory, Brooklyn, New York
| | - Hanh T. Nguyen
- The International AIDS Vaccine Initiative, AIDS Vaccine Design and Development Laboratory, Brooklyn, New York
- Program in Molecular and Cellular Biology, School of Graduate Studies, The State University of New York Downstate Medical Center, Brooklyn, New York
| | - Marina Kemelman
- The International AIDS Vaccine Initiative, AIDS Vaccine Design and Development Laboratory, Brooklyn, New York
| | - Ross W. Lindsay
- The International AIDS Vaccine Initiative, AIDS Vaccine Design and Development Laboratory, Brooklyn, New York
| | - Maoli Yuan
- The International AIDS Vaccine Initiative, AIDS Vaccine Design and Development Laboratory, Brooklyn, New York
| | - Kevin J. Wright
- The International AIDS Vaccine Initiative, AIDS Vaccine Design and Development Laboratory, Brooklyn, New York
| | - Heather Arendt
- The International AIDS Vaccine Initiative, AIDS Vaccine Design and Development Laboratory, Brooklyn, New York
| | | | - Joanne DeStefano
- The International AIDS Vaccine Initiative, AIDS Vaccine Design and Development Laboratory, Brooklyn, New York
| | - Simon Hoffenberg
- The International AIDS Vaccine Initiative, AIDS Vaccine Design and Development Laboratory, Brooklyn, New York
| | - Gavin Morrow
- The International AIDS Vaccine Initiative, AIDS Vaccine Design and Development Laboratory, Brooklyn, New York
| | - Christy K. Jurgens
- The International AIDS Vaccine Initiative, AIDS Vaccine Design and Development Laboratory, Brooklyn, New York
| | - Sanjay K. Phogat
- The International AIDS Vaccine Initiative, AIDS Vaccine Design and Development Laboratory, Brooklyn, New York
| | - Timothy J. Zamb
- The International AIDS Vaccine Initiative, AIDS Vaccine Design and Development Laboratory, Brooklyn, New York
| | - Christopher L. Parks
- The International AIDS Vaccine Initiative, AIDS Vaccine Design and Development Laboratory, Brooklyn, New York
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Schwarzer R, Levental I, Gramatica A, Scolari S, Buschmann V, Veit M, Herrmann A. The cholesterol-binding motif of the HIV-1 glycoprotein gp41 regulates lateral sorting and oligomerization. Cell Microbiol 2014; 16:1565-81. [PMID: 24844300 DOI: 10.1111/cmi.12314] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Revised: 04/24/2014] [Accepted: 05/13/2014] [Indexed: 12/12/2022]
Abstract
Enveloped viruses often use membrane lipid rafts to assemble and bud, augment infection and spread efficiently. However, the molecular bases and functional consequences of the partitioning of viral glycoproteins into microdomains remain intriguing questions in virus biology. Here, we measured Foerster resonance energy transfer by fluorescence lifetime imaging microscopy (FLIM-FRET) to study the role of distinct membrane proximal regions of the human immunodeficiency virus glycoprotein gp41 for lipid raft partitioning in living Chinese hamster ovary cells (CHO-K1). Gp41 was labelled with a fluorescent protein at the exoplasmic face of the membrane, preventing any interference of the fluorophore with the proposed role of the transmembrane and cytoplasmic domains in lateral organization of gp41. Raft localization was deduced from interaction with an established raft marker, a fluorescently tagged glycophosphatidylinositol anchor and the cholesterol recognition amino acid consensus (CRAC) was identified as the crucial lateral sorting determinant in CHO-K1 cells. Interestingly, the raft association of gp41 indicates a substantial cell-to-cell heterogeneity of the plasma membrane microdomains. In complementary fluorescence polarization microscopy, a distinct CRAC requirement was found for the oligomerization of the gp41 variants. Our data provide further insight into the molecular basis and biological implications of the cholesterol dependent lateral sorting of viral glycoproteins for virus assembly at cellular membranes.
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Affiliation(s)
- Roland Schwarzer
- Department of Biology, Molecular Biophysics, Humboldt University, 10115, Berlin, Germany
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31
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Tong T, Crooks ET, Osawa K, Robinson JE, Barnes M, Apetrei C, Binley JM. Multi-Parameter Exploration of HIV-1 Virus-Like Particles as Neutralizing Antibody Immunogens in Guinea Pigs, Rabbits and Macaques. Virology 2014; 456-457:55-69. [PMID: 24882891 PMCID: PMC4037872 DOI: 10.1016/j.virol.2014.03.015] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Revised: 02/26/2014] [Accepted: 03/13/2014] [Indexed: 12/18/2022]
Abstract
Virus-like particles (VLPs) offer a platform to test the hypothesis that, since antibody binding to native envelope glycoprotein (Env) trimers results in HIV-1 neutralization, that native Env trimers presented in membranes may be useful for inducing neutralizing antibodies (nAbs) in a vaccine setting. So far, VLPs have not fulfilled this potential. Here, using a "shotgun" approach, we evaluated a wide cross-section of variables in a series of VLP immunizations. We identified 3 tentative leads. First, that VLP doses may not have been sufficient for optimal nAb induction. Second, that dampening the antigenicity of non-functional Env (for example uncleaved gp160) using either protease digests or IgG masking may be useful. Third, that guinea pig sera preferentially target non-conserved epitopes and exhibit relatively high background activity, suggesting that rabbits may be preferable as small animal vaccine models. Recent immunogenicity studies in rabbits appear to bear out all 3 of these leads.
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Affiliation(s)
- Tommy Tong
- Torrey Pines Institute for Molecular Studies, 3550 General Atomics Court, San Diego, CA 92121, USA
| | - Ema T. Crooks
- Torrey Pines Institute for Molecular Studies, 3550 General Atomics Court, San Diego, CA 92121, USA
| | - Keiko Osawa
- Torrey Pines Institute for Molecular Studies, 3550 General Atomics Court, San Diego, CA 92121, USA
| | | | - Mary Barnes
- Tulane National Primate Research Center, 18703 Three Rivers Rd, Covington, LA 70433, USA
| | - Cristian Apetrei
- Tulane National Primate Research Center, 18703 Three Rivers Rd, Covington, LA 70433, USA
| | - James M. Binley
- Torrey Pines Institute for Molecular Studies, 3550 General Atomics Court, San Diego, CA 92121, USA
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32
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Aiamkitsumrit B, Dampier W, Antell G, Rivera N, Martin-Garcia J, Pirrone V, Nonnemacher MR, Wigdahl B. Bioinformatic analysis of HIV-1 entry and pathogenesis. Curr HIV Res 2014; 12:132-61. [PMID: 24862329 PMCID: PMC4382797 DOI: 10.2174/1570162x12666140526121746] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Revised: 03/18/2014] [Accepted: 05/06/2014] [Indexed: 02/07/2023]
Abstract
The evolution of human immunodeficiency virus type 1 (HIV-1) with respect to co-receptor utilization has been shown to be relevant to HIV-1 pathogenesis and disease. The CCR5-utilizing (R5) virus has been shown to be important in the very early stages of transmission and highly prevalent during asymptomatic infection and chronic disease. In addition, the R5 virus has been proposed to be involved in neuroinvasion and central nervous system (CNS) disease. In contrast, the CXCR4-utilizing (X4) virus is more prevalent during the course of disease progression and concurrent with the loss of CD4(+) T cells. The dual-tropic virus is able to utilize both co-receptors (CXCR4 and CCR5) and has been thought to represent an intermediate transitional virus that possesses properties of both X4 and R5 viruses that can be encountered at many stages of disease. The use of computational tools and bioinformatic approaches in the prediction of HIV-1 co-receptor usage has been growing in importance with respect to understanding HIV-1 pathogenesis and disease, developing diagnostic tools, and improving the efficacy of therapeutic strategies focused on blocking viral entry. Current strategies have enhanced the sensitivity, specificity, and reproducibility relative to the prediction of co-receptor use; however, these technologies need to be improved with respect to their efficient and accurate use across the HIV-1 subtypes. The most effective approach may center on the combined use of different algorithms involving sequences within and outside of the env-V3 loop. This review focuses on the HIV-1 entry process and on co-receptor utilization, including bioinformatic tools utilized in the prediction of co-receptor usage. It also provides novel preliminary analyses for enabling identification of linkages between amino acids in V3 with other components of the HIV-1 genome and demonstrates that these linkages are different between X4 and R5 viruses.
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Affiliation(s)
| | | | | | | | | | | | | | - Brian Wigdahl
- Department of Microbiology and Immunology, Drexel University College of Medicine, 245 N. 15th Street, Philadelphia, PA 19102.
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Dobrowsky TM, Rabi SA, Nedellec R, Daniels BR, Mullins JI, Mosier DE, Siliciano RF, Wirtz D. Adhesion and fusion efficiencies of human immunodeficiency virus type 1 (HIV-1) surface proteins. Sci Rep 2013; 3:3014. [PMID: 24145278 PMCID: PMC3804852 DOI: 10.1038/srep03014] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2013] [Accepted: 09/30/2013] [Indexed: 12/20/2022] Open
Abstract
In about half of patients infected with HIV-1 subtype B, viral populations shift from utilizing the transmembrane protein CCR5 to CXCR4, as well as or instead of CCR5, during late stage progression of the disease. How the relative adhesion efficiency and fusion competency of the viral Env proteins relate to infection during this transition is not well understood. Using a virus-cell fusion assay and live-cell single-molecule force spectroscopy, we compare the entry competency of viral clones to tensile strengths of the individual Env-receptor bonds of Env proteins obtained from a HIV-1 infected patient prior to and during coreceptor switching. The results suggest that the genetic determinants of viral entry were predominantly enriched in the C3, HR1 and CD regions rather than V3. Env proteins can better mediate entry into cells after coreceptor switch; this effective entry capacity does not correlate with the bond strengths between viral Env and cellular receptors.
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Affiliation(s)
- Terrence M Dobrowsky
- 1] Department of Chemical and Biomolecular Engineering, The Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, USA [2]
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34
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Visciano ML, Tagliamonte M, Stewart-Jones G, Heyndrickx L, Vanham G, Jansson M, Fomsgaard A, Grevstad B, Ramaswamy M, Buonaguro FM, Tornesello ML, Biswas P, Scarlatti G, Buonaguro L. Characterization of humoral responses to soluble trimeric HIV gp140 from a clade A Ugandan field isolate. J Transl Med 2013; 11:165. [PMID: 23835244 PMCID: PMC3729709 DOI: 10.1186/1479-5876-11-165] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2013] [Accepted: 06/20/2013] [Indexed: 11/25/2022] Open
Abstract
Trimeric soluble forms of HIV gp140 envelope glycoproteins represent one of the closest molecular structures compared to native spikes present on intact virus particles. Trimeric soluble gp140 have been generated by several groups and such molecules have been shown to induce antibodies with neutralizing activity against homologous and heterologous viruses. In the present study, we generated a recombinant trimeric soluble gp140, derived from a previously identified Ugandan A-clade HIV field isolate (gp14094UG018). Antibodies elicited in immunized rabbits show a broad binding pattern to HIV envelopes of different clades. An epitope mapping analysis reveals that, on average, the binding is mostly focused on the C1, C2, V3, V5 and C5 regions. Immune sera show neutralization activity to Tier 1 isolates of different clades, demonstrating cross clade neutralizing activity which needs to be further broadened by possible structural modifications of the clade A gp14094UG018. Our results provide a rationale for the design and evaluation of immunogens and the clade A gp14094UG018 shows promising characteristics for potential involvement in an effective HIV vaccine with broad activity.
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Affiliation(s)
- Maria Luisa Visciano
- Molecular Biology and Viral Oncogenesis Unit, Department of Experimental Oncology, Istituto Nazionale per lo Studio e la Cura dei Tumori "Fondazione Pascale" - IRCCS, Naples, Italy
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35
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Stolp ZD, Stotland A, Diaz S, Hilton BJ, Burford W, Wolkowicz R. A Novel Two-Tag System for Monitoring Transport and Cleavage through the Classical Secretory Pathway - Adaptation to HIV Envelope Processing. PLoS One 2013; 8:e68835. [PMID: 23840860 PMCID: PMC3686725 DOI: 10.1371/journal.pone.0068835] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2013] [Accepted: 06/03/2013] [Indexed: 11/19/2022] Open
Abstract
The classical secretory pathway is essential for the transport of a host of proteins to the cell surface and/or extracellular matrix. While the pathway is well-established, many factors still remain to be elucidated. One of the most relevant biological processes that occur during transport involves the cleavage of pro-proteins by enzymes residing in the endoplasmic reticulum/Golgi/TransGolgi Network compartment. Teasing out the requirements involved in the classical secretory pathway and cleavage during transport would shed new light into mis-regulation leading to disease. Current methodologies fail to link transport and cleavage at the single cell level. Here, we describe a cell-based assay that relies on an engineered protein scaffold that can discriminate between transport to the cell surface, in the absence or presence of cleavage. Our novel two-tag system works in a robust and quantitative manner and distinguishes between cleaved and non-cleaved events based on cell surface expression of one or two epitope tags, respectively. Here, we have used the HIV-1 envelope as a substrate, which is cleaved during transport, as proof of principle. Importantly, this assay can be easily coupled to existing siRNA-based screens to identify novel regulators and effectors involved in transport and/or cleavage of cell surface proteins. In addition, unlike other in vivo based assays, the assay described here can also be easily adapted to drug discovery purposes.
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Affiliation(s)
- Zachary D. Stolp
- Department of Biology, San Diego State University, San Diego, California, United States of America
| | - Aleksandr Stotland
- Department of Biology, San Diego State University, San Diego, California, United States of America
| | - Samantha Diaz
- Department of Biology, San Diego State University, San Diego, California, United States of America
| | - Brett J. Hilton
- Department of Biology, San Diego State University, San Diego, California, United States of America
| | - Wesley Burford
- Department of Biology, San Diego State University, San Diego, California, United States of America
| | - Roland Wolkowicz
- Department of Biology, San Diego State University, San Diego, California, United States of America
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36
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Santos da Silva E, Mulinge M, Perez Bercoff D. The frantic play of the concealed HIV envelope cytoplasmic tail. Retrovirology 2013; 10:54. [PMID: 23705972 PMCID: PMC3686653 DOI: 10.1186/1742-4690-10-54] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Accepted: 05/01/2013] [Indexed: 11/18/2022] Open
Abstract
Lentiviruses have unusually long envelope (Env) cytoplasmic tails, longer than those of other retroviruses. Whereas the Env ectodomain has received much attention, the gp41 cytoplasmic tail (gp41-CT) is one of the least studied parts of the virus. It displays relatively high conservation compared to the rest of Env. It has been long established that the gp41-CT interacts with the Gag precursor protein to ensure Env incorporation into the virion. The gp41-CT contains distinct motifs and domains that mediate both intensive Env intracellular trafficking and interactions with numerous cellular and viral proteins, optimizing viral infectivity. Although they are not fully understood, a multiplicity of interactions between the gp41-CT and cellular factors have been described over the last decade; these interactions illustrate how Env expression and incorporation into virions is a finely tuned process that has evolved to best exploit the host system with minimized genetic information. This review addresses the structure and topology of the gp41-CT of lentiviruses (mainly HIV and SIV), their domains and believed functions. It also considers the cellular and viral proteins that have been described to interact with the gp41-CT, with a particular focus on subtype-related polymorphisms.
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37
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Purification of recombinant vaccinia virus-expressed monomeric HIV-1 gp120 to apparent homogeneity. Protein Expr Purif 2013; 90:34-9. [PMID: 23665667 DOI: 10.1016/j.pep.2013.04.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2013] [Revised: 04/27/2013] [Accepted: 04/29/2013] [Indexed: 11/22/2022]
Abstract
Vaccinia virus (VV) has been used to express a variety of heterologous proteins, including HIV envelope (Env) glycoproteins. The Env protein is synthesized as a precursor molecule, gp160, which is cleaved into the surface antigen gp120 and the transmembrane protein gp41. Even though production of gp160 by the VV expression system has been described, its use for gp120 production is not well documented. Here we report a new procedure for the purification of gp120 from serum-containing culture supernatant of VV-infected cells. The gp120 protein was enriched to a purity better than 60% on a snowdrop (Galanthus nivalis) lectin affinity column in the presence of 0.25% zwitterionic detergent Empigen BB. After additional DEAE anion exchange and Superdex size exclusion chromatography steps, the gp120 monomer was purified free of contamination as determined by SDS-PAGE. The retention of structural integrity was confirmed by determining the affinity constant of purified gp120s to soluble CD4 and a monoclonal antibody IgG1b12, using surface plasmon resonance analysis. The purification procedure is robust and reproducible, and may find general use for glycoprotein purifications from sources where the presence of serum is desirable.
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Biochemical reconstitution of hemorrhagic-fever arenavirus envelope glycoprotein-mediated membrane fusion. PLoS One 2012; 7:e51114. [PMID: 23226473 PMCID: PMC3511403 DOI: 10.1371/journal.pone.0051114] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2012] [Accepted: 10/16/2012] [Indexed: 11/19/2022] Open
Abstract
The membrane-anchored proteins of enveloped viruses form labile spikes on the virion surface, primed to undergo large-scale conformational changes culminating in virus-cell membrane fusion and viral entry. The prefusion form of these envelope glycoproteins thus represents an important molecular target for antiviral intervention. A critical roadblock to this endeavor has been our inability to produce the prefusion envelope glycoprotein trimer for biochemical and structural analysis. Through our studies of the GPC envelope glycoprotein of the hemorrhagic fever arenaviruses, we have shown that GPC is unique among class I viral fusion proteins in that the mature complex retains a stable signal peptide (SSP) in addition to the conventional receptor-binding and transmembrane fusion subunits. In this report we show that the recombinant GPC precursor can be produced as a discrete native-like trimer and that its proteolytic cleavage generates the mature glycoprotein. Proteoliposomes containing the cleaved GPC mediate pH-dependent membrane fusion, a characteristic feature of arenavirus entry. This reaction is inhibited by arenavirus-specific monoclonal antibodies and small-molecule fusion inhibitors. The in vitro reconstitution of GPC-mediated membrane-fusion activity offers unprecedented opportunities for biochemical and structural studies of arenavirus entry and its inhibition. To our knowledge, this report is the first to demonstrate functional reconstitution of membrane fusion by a viral envelope glycoprotein.
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Steckbeck JD, Kuhlmann AS, Montelaro RC. C-terminal tail of human immunodeficiency virus gp41: functionally rich and structurally enigmatic. J Gen Virol 2012; 94:1-19. [PMID: 23079381 PMCID: PMC3542723 DOI: 10.1099/vir.0.046508-0] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
The human immunodeficiency virus (HIV) and acquired immunodeficiency syndrome (AIDS) pandemic is amongst the most important current worldwide public health threats. While much research has been focused on AIDS vaccines that target the surface viral envelope (Env) protein, including gp120 and the gp41 ectodomain, the C-terminal tail (CTT) of gp41 has received relatively little attention. Despite early studies highlighting the immunogenicity of a particular CTT sequence, the CTT has been classically portrayed as a type I membrane protein limited to functioning in Env trafficking and virion incorporation. Recent studies demonstrate, however, that the Env CTT has other important functions. The CTT has been shown to additionally modulate Env ectodomain structure on the cell and virion surface, affect Env reactivity and viral sensitivity to conformation-dependent neutralizing antibodies, and alter cell–cell and virus–cell fusogenicity of Env. This review provides an overview of the Env structure and function with a particular emphasis on the CTT and recent studies that highlight its functionally rich nature.
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Affiliation(s)
- Jonathan D. Steckbeck
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15261, USA
- Center for Vaccine Research, University of Pittsburgh, Pittsburgh, PA, 15261, USA
| | - Anne-Sophie Kuhlmann
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15261, USA
- Center for Vaccine Research, University of Pittsburgh, Pittsburgh, PA, 15261, USA
| | - Ronald C. Montelaro
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15261, USA
- Center for Vaccine Research, University of Pittsburgh, Pittsburgh, PA, 15261, USA
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Feng Y, McKee K, Tran K, O'Dell S, Schmidt SD, Phogat A, Forsell MN, Karlsson Hedestam GB, Mascola JR, Wyatt RT. Biochemically defined HIV-1 envelope glycoprotein variant immunogens display differential binding and neutralizing specificities to the CD4-binding site. J Biol Chem 2011; 287:5673-86. [PMID: 22167180 DOI: 10.1074/jbc.m111.317776] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
HIV-1 gp120 binds the primary receptor CD4. Recently, a plethora of broadly neutralizing antibodies to the gp120 CD4-binding site (CD4bs) validated this region as a target for immunogen design. Here, we asked if modified HIV-1 envelope glycoproteins (Env) designed to increase CD4 recognition might improve recognition by CD4bs neutralizing antibodies and more efficiently elicit such reactivities. We also asked if CD4bs stabilization, coupled with altering the Env format (monomer to trimer or cross-clade), might better elicit neutralizing antibodies by focusing the immune response on the functionally conserved CD4bs. We produced monomeric and trimeric Envs stabilized by mutations within the gp120 CD4bs cavity (pocket-filling; PF2) or by appending heterologous trimerization motifs to soluble Env ectodomains (gp120/gp140). Recombinant glycoproteins were purified to relative homogeneity, and ligand binding properties were analyzed by ELISA, surface plasmon resonance, and isothermal titration microcalorimetry. In some formats, the PF2 substitutions increased CD4 affinity, and importantly, PF2-containing proteins were better recognized by the broadly neutralizing CD4bs mAbs, VRC01 and VRC-PG04. Based on this analysis, we immunized selected Env variants into rabbits using heterologous or homologous regimens. Analysis of the sera revealed that homologous inoculation of the PF2-containing, variable region-deleted YU2 gp120 trimers (ΔV123/PF2-GCN4) more rapidly elicited CD4bs-directed neutralizing antibodies compared with other regimens, whereas homologous trimers elicited increased neutralization potency, mapping predominantly to the gp120 third major variable region (V3). These results suggest that some engineered Env proteins may more efficiently direct responses toward the conserved CD4bs and be valuable to elicit antibodies of greater neutralizing capacity.
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Affiliation(s)
- Yu Feng
- IAVI Neutralizing Antibody Center, Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, California 92037, USA
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41
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Engineering, expression, purification, and characterization of stable clade A/B recombinant soluble heterotrimeric gp140 proteins. J Virol 2011; 86:128-42. [PMID: 22031951 DOI: 10.1128/jvi.06363-11] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The envelope glycoprotein (Env) of human immunodeficiency virus type 1 (HIV-1) is composed of two noncovalently associated subunits: an extracellular subunit (gp120) and a transmembrane subunit (gp41). The functional unit of Env on the surface of infectious virions is a trimer of gp120/gp41 heterodimers. Env is the target of anti-HIV neutralizing antibodies. A considerable effort has been invested in the engineering of recombinant soluble forms of the virion-associated Env trimer as vaccine candidates to elicit anti-HIV neutralizing antibody responses. These soluble constructs contain three gp120 subunits and the extracellular segments of the corresponding gp41 subunits. The individual gp120/gp41 protomers on these soluble trimers are identical in amino acid sequence (homotrimers). Here, we engineered novel soluble trimeric gp140 proteins that are formed by the association of gp140 protomers that differ in amino acid sequence and glycosylation patterns (heterotrimers). Specifically, we engineered soluble heterotrimeric proteins composed of clade A and clade B Env protomers. The clade A gp140 protomers were derived from viruses isolated during acute infection (Q168a2, Q259d2.17, and Q461e2), whereas the clade B gp140 protomers were derived from a virus isolated during chronic infection (SF162). The amino acid sequence divergence between the clade A and the clade B Envs is approximately 24%. Neutralization epitopes in the CD4 binding sites and coreceptor binding sites, as well as the membrane-proximal external region (MPER), were differentially expressed on the heterotrimeric and homotrimeric proteins. The heterotrimeric gp140s elicited broader anti-tier 1 isolate neutralizing antibody responses than did the homotrimeric gp140s.
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Checkley MA, Luttge BG, Freed EO. HIV-1 envelope glycoprotein biosynthesis, trafficking, and incorporation. J Mol Biol 2011; 410:582-608. [PMID: 21762802 PMCID: PMC3139147 DOI: 10.1016/j.jmb.2011.04.042] [Citation(s) in RCA: 328] [Impact Index Per Article: 25.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2011] [Revised: 04/14/2011] [Accepted: 04/15/2011] [Indexed: 12/13/2022]
Abstract
The HIV-1 envelope (Env) glycoproteins play an essential role in the virus replication cycle by mediating the fusion between viral and cellular membranes during the entry process. The Env glycoproteins are synthesized as a polyprotein precursor (gp160) that is cleaved by cellular proteases to the mature surface glycoprotein gp120 and the transmembrane glycoprotein gp41. During virus assembly, the gp120/gp41 complex is incorporated as heterotrimeric spikes into the lipid bilayer of nascent virions. These gp120/gp41 complexes then initiate the infection process by binding receptor and coreceptor on the surface of target cells. Much is currently known about the HIV-1 Env glycoprotein trafficking pathway and the structure of gp120 and the extracellular domain of gp41. However, the mechanism by which the Env glycoprotein complex is incorporated into virus particles remains incompletely understood. Genetic data support a major role for the cytoplasmic tail of gp41 and the matrix domain of Gag in Env glycoprotein incorporation. Still to be defined are the identities of host cell factors that may promote Env incorporation and the role of specific membrane microdomains in this process. Here, we review our current understanding of HIV-1 Env glycoprotein trafficking and incorporation into virions.
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Affiliation(s)
- Mary Ann Checkley
- Virus-Cell Interaction Section, HIV Drug Resistance Program National Cancer Institute Frederick, MD 21702
| | - Benjamin G. Luttge
- Virus-Cell Interaction Section, HIV Drug Resistance Program National Cancer Institute Frederick, MD 21702
| | - Eric O. Freed
- Virus-Cell Interaction Section, HIV Drug Resistance Program National Cancer Institute Frederick, MD 21702
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Mechanism of neutralization by the broadly neutralizing HIV-1 monoclonal antibody VRC01. J Virol 2011; 85:8954-67. [PMID: 21715490 DOI: 10.1128/jvi.00754-11] [Citation(s) in RCA: 190] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The structure of VRC01 in complex with the HIV-1 gp120 core reveals that this broadly neutralizing CD4 binding site (CD4bs) antibody partially mimics the interaction of the primary virus receptor, CD4, with gp120. Here, we extended the investigation of the VRC01-gp120 core interaction to the biologically relevant viral spike to better understand the mechanism of VRC01-mediated neutralization and to define viral elements associated with neutralization resistance. In contrast to the interaction of CD4 or the CD4bs monoclonal antibody (MAb) b12 with the HIV-1 envelope glycoprotein (Env), occlusion of the VRC01 epitope by quaternary constraints was not a major factor limiting neutralization. Mutagenesis studies indicated that VRC01 contacts within the gp120 loop D, the CD4 binding loop, and the V5 region were necessary for optimal VRC01 neutralization, as suggested by the crystal structure. In contrast to interactions with the soluble gp120 monomer, VRC01 interaction with the native viral spike did not occur in a CD4-like manner; VRC01 did not induce gp120 shedding from the Env spike or enhance gp41 membrane proximal external region (MPER)-directed antibody binding to the Env spike. Finally, VRC01 did not display significant reactivity with human antigens, boding well for potential in vivo applications. The data indicate that VRC01 interacts with gp120 in the context of the functional spike in a manner distinct from that of CD4. It achieves potent neutralization by precisely targeting the CD4bs without requiring alterations of Env spike configuration and by avoiding steric constraints imposed by the quaternary structure of the functional Env spike.
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Enzyme digests eliminate nonfunctional Env from HIV-1 particle surfaces, leaving native Env trimers intact and viral infectivity unaffected. J Virol 2011; 85:5825-39. [PMID: 21471242 DOI: 10.1128/jvi.00154-11] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
HIV-1 viruses and virus-like particles (VLPs) bear nonnative "junk" forms of envelope (Env) glycoprotein that may undermine the development of antibody responses against functional gp120/gp41 trimers, thereby blunting the ability of particles to elicit neutralizing antibodies. Here, we sought to better understand the nature of junk Env with a view to devising strategies for its removal. Initial studies revealed that native trimers were surprisingly stable in the face of harsh conditions, suggesting that junk Env is unlikely to arise by trimer dissociation or gp120 shedding. Furthermore, the limited gp120 shedding that occurs immediately after synthesis of primary HIV-1 isolate Envs is not caused by aberrant cleavage at the tandem gp120/gp41 cleavage sites, which were found to cleave in a codependent manner. A major VLP contaminant was found to consist of an early, monomeric form of gp160 that is glycosylated in the endoplasmic reticulum (gp160ER) and then bypasses protein maturation and traffics directly into particles. gp160ER was found to bind two copies of monoclonal antibody (MAb) 2G12, consistent with its exclusively high-mannose glycan profile. These findings prompted us to evaluate enzyme digests as a way to remove aberrant Env. Remarkably, sequential glycosidase-protease digests led to a complete or near-complete removal of junk Env from many viral strains, leaving trimers and viral infectivity largely intact. "Trimer VLPs" may be useful neutralizing antibody immunogens.
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46
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Quaternary structures of HIV Env immunogen exhibit conformational vicissitudes and interface diminution elicited by ligand binding. Proc Natl Acad Sci U S A 2011; 108:6091-6. [PMID: 21444771 DOI: 10.1073/pnas.1016113108] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The human immunodeficiency virus envelope protein is the key element mediating entry into host cells. Conformational rearrangement of Env upon binding to the host CD4 receptor and chemokine coreceptor drives membrane fusion. We elucidated the quaternary arrangement of the soluble Env trimeric immunogen o-gp140ΔV2TV1, in both its native (unliganded) and CD4-induced (liganded) states by cryoelectron microscopy and molecular modeling. The liganded conformation was elicited by binding gp140 to the synthetic CD4-mimicking miniprotein CD4m. Upon CD4m binding, an outward domain shift of the three gp120 subunits diminishes gp120-gp41 interactions, whereas a "flat open" concave trimer apex is observed consequent to gp120 tilting away from threefold axis, likely juxtaposing the fusion peptide with the host membrane. Additional features observed in the liganded conformation include rotations of individual gp120 subunits that may release gp41 for N- and C-helix refolding and also may lead to optimal exposure of the elicited coreceptor binding site. Such quaternary arrangements of gp140 lead to the metastable liganded conformation, with putative locations of exposed epitopes contributing to a description of sequential events occurring prior to membrane fusion. Our observations imply a mechanism whereby a soluble Env trimeric construct, as opposed to trimers extracted from virions, may better expose crucial epitopes such as the CD4 binding site and V3, as well as epitopes in the vicinity of gp41, subsequent to conjugation with CD4m. Structural features gleaned from our studies should aid the design of Env-based immunogens for inducement of potent broadly neutralizing antibodies against exposed conformational epitopes.
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47
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Wang Z, Zhang M, Wang Y, Jiao Y, Zhang L, Li L, Huang Z, Wu H, Li J, Lu S, Wang S. A versatile vector for the production of pseudotyped viruses expressing gp120 antigens from different clades of primary HIV-1 isolates. J Virol Methods 2011; 171:183-9. [PMID: 21034776 PMCID: PMC3011055 DOI: 10.1016/j.jviromet.2010.10.022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2010] [Revised: 10/19/2010] [Accepted: 10/21/2010] [Indexed: 10/18/2022]
Abstract
A novel HIV-1 Env expression vector (SF162-Z) was developed by introducing two new cloning sites on the backbone of an existing vector that produces a full length Env from HIV-1 SF162 isolate. These sites facilitate the swapping of the gp120 portion of the SF162 Env with matching gp120 antigens from HIV-1 isolates of different genetic clades. Final production of functional pseudotyped viruses will express chimeric Env antigens, including gp41 of the parental SF162 and gp120 from other primary isolates. This system is useful for testing the neutralizing sensitivity of partial env gene products frequently identified in viral quasi species in patients infected with HIV or when only partial gp120 gene products are available.
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Affiliation(s)
- Zheng Wang
- Laboratory of Nucleic Acid Vaccines, Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01655, USA
- Department of HIV/AIDS Research, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
| | - Mingshun Zhang
- China-USA Vaccine Research Center and Jiangsu Province Key Laboratory in Infectious Disease, Department of Infectious Diseases, the First Affiliated Hospital, Nanjing Medical University, Nanjing 210029, China
| | - Yan Wang
- Laboratory of Nucleic Acid Vaccines, Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Yanmei Jiao
- Department of Infectious Diseases, Youan Hospital, Capital Medical University, Beijing 100069, China
| | - Lu Zhang
- China-USA Vaccine Research Center and Jiangsu Province Key Laboratory in Infectious Disease, Department of Infectious Diseases, the First Affiliated Hospital, Nanjing Medical University, Nanjing 210029, China
| | - Lin Li
- Department of HIV/AIDS Research, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
| | - Zuhu Huang
- China-USA Vaccine Research Center and Jiangsu Province Key Laboratory in Infectious Disease, Department of Infectious Diseases, the First Affiliated Hospital, Nanjing Medical University, Nanjing 210029, China
| | - Hao Wu
- Department of Infectious Diseases, Youan Hospital, Capital Medical University, Beijing 100069, China
| | - Jingyun Li
- Department of HIV/AIDS Research, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
| | - Shan Lu
- Laboratory of Nucleic Acid Vaccines, Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01655, USA
- China-USA Vaccine Research Center and Jiangsu Province Key Laboratory in Infectious Disease, Department of Infectious Diseases, the First Affiliated Hospital, Nanjing Medical University, Nanjing 210029, China
| | - Shixia Wang
- Laboratory of Nucleic Acid Vaccines, Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01655, USA
- China-USA Vaccine Research Center and Jiangsu Province Key Laboratory in Infectious Disease, Department of Infectious Diseases, the First Affiliated Hospital, Nanjing Medical University, Nanjing 210029, China
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Thomas CJ, Casquilho-Gray HE, York J, DeCamp DL, Dai D, Petrilli EB, Boger DL, Slayden RA, Amberg SM, Sprang SR, Nunberg JH. A specific interaction of small molecule entry inhibitors with the envelope glycoprotein complex of the Junín hemorrhagic fever arenavirus. J Biol Chem 2010; 286:6192-200. [PMID: 21159779 DOI: 10.1074/jbc.m110.196428] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Arenaviruses are responsible for acute hemorrhagic fevers worldwide and are recognized to pose significant threats to public health and biodefense. Small molecule compounds have recently been discovered that inhibit arenavirus entry and protect against lethal infection in animal models. These chemically distinct inhibitors act on the tripartite envelope glycoprotein (GPC) through its unusual stable signal peptide subunit to stabilize the complex against pH-induced activation of membrane fusion in the endosome. Here, we report the production and characterization of the intact transmembrane GPC complex of Junín arenavirus and its interaction with these inhibitors. The solubilized GPC is antigenically indistinguishable from the native protein and forms a homogeneous trimer in solution. When reconstituted into a lipid bilayer, the purified complex interacts specifically with its cell-surface receptor transferrin receptor-1. We show that small molecule entry inhibitors specific to New World or Old World arenaviruses bind to the membrane-associated GPC complex in accordance with their respective species selectivities and with dissociation constants comparable with concentrations that inhibit GPC-mediated membrane fusion. Furthermore, competitive binding studies reveal that these chemically distinct inhibitors share a common binding pocket on GPC. In conjunction with previous genetic studies, these findings identify the pH-sensing interface of GPC as a highly vulnerable target for antiviral intervention. This work expands our mechanistic understanding of arenavirus entry and provides a foundation to guide the development of small molecule compounds for the treatment of arenavirus hemorrhagic fevers.
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Affiliation(s)
- Celestine J Thomas
- Center for Biomolecular Structure and Dynamics, University of Montana, Missoula, Montana 59812, USA.
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Functional contributions of carbohydrate on AIDS virus glycoprotein. THE YALE JOURNAL OF BIOLOGY AND MEDICINE 2010; 83:201-8. [PMID: 21165339 PMCID: PMC3002149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
Envelope glycoprotein spikes on the surface of the human immunodeficiency virus (HIV) are used by the virus to bind to cellular receptors to gain entry into target cells. As such, the envelope spikes are the targets of antibodies that can neutralize viral infectivity. Fifty percent or more of the mass of the viral-encoded surface glycoprotein of HIV, and of its close monkey relative simian immunodeficiency virus (SIV), is actually carbohydrate; it is one of the most heavily glycosylated proteins that can be found in mammals. It has been clearly demonstrated that one of the functions of this carbohydrate is to shield viral epitopes that would otherwise be the direct target of antibodies that could neutralize viral infection. In addition, it is now generally accepted that the carbohydrate on the viral envelope glycoprotein is recognized by multiple cellular lectins of the host lymphoreticular system, and these interactions play a role in the dissemination of virus within the host as well as the release of modulatory cytokines. Our work recently demonstrated fundamental differences in the composition of the carbohydrate on HIV type 1, the cause of the AIDS pandemic, versus the SIV in the sooty mangabey monkey, a natural host that does not develop disease from its infection. We now speculate that this fundamental difference in carbohydrate composition reflects evolutionary pressures on both virus and host. Furthermore, carbohydrate composition on the virus and genetic differences in carbohydrate-sensing proteins of the host could be critically important for the generalized lymphoid activation that characterizes the acquired immunodeficiency syndrome (AIDS).
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50
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Conformational characterization of aberrant disulfide-linked HIV-1 gp120 dimers secreted from overexpressing cells. J Virol Methods 2010; 168:155-61. [PMID: 20471426 DOI: 10.1016/j.jviromet.2010.05.008] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2010] [Revised: 04/01/2010] [Accepted: 05/06/2010] [Indexed: 11/23/2022]
Abstract
The envelope (Env) glycoproteins of human immunodeficiency virus (HIV-1) mediate viral entry and are also the primary target of neutralizing antibodies. The gp160 envelope glycoprotein precursor undergoes proteolytic cleavage in the Golgi complex to produce the gp120 exterior glycoprotein and the gp41 transmembrane glycoprotein, which remain associated non-covalently in the trimeric Env complex. Monomeric soluble gp120 has been used extensively to investigate conformational states, structure, antigenicity and immunogenicity of the HIV-1 Env glycoproteins. Expression of gp120 alone (without gp41) leads to the accumulation not only of monomeric gp120 but also an aberrant dimeric form. The gp120 dimers were sensitive to reducing agents. The formation of gp120 dimers was disrupted by a single amino acid change in the inner domain, and was reduced by removal of the V1/V2 variable loops or the N and C termini. Epitopes on the gp120 inner domain and the chemokine receptor-binding surface were altered or occluded by gp120 dimerization. Awareness of the existence and properties of gp120 dimers should assist interpretation of studies of this key viral protein.
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