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Meng G, Pu J, Li Y, Han A, Tian Y, Xu W, Zhang T, Li X, Lu L, Wang C, Jiang S, Liu K. Design and Biological Evaluation of m-Xylene Thioether-Stapled Short Helical Peptides Targeting the HIV-1 gp41 Hexameric Coiled-Coil Fusion Complex. J Med Chem 2019; 62:8773-8783. [PMID: 31513410 DOI: 10.1021/acs.jmedchem.9b00882] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Short peptide-based inhibition of fusion remains an attractive goal in antihuman immunodeficiency virus (HIV) research based on its potential for the development of technically and economically desirable antiviral agents. Herein, we report the use of the dithiol bisalkylation reaction to generate a series of m-xylene thioether-stapled 22-residue α-helical peptides that have been identified as fusion inhibitors targeting HIV-1 glycoprotein 41 (gp41). The peptide sequence is based on the helix-zone binding domain of the gp41 C-terminal heptad repeat region. We found that one of these stapled peptides, named hCS6ERE, showed promising inhibitory potency against HIV-1 Env-mediated cell-cell fusion and viral replication at a level comparable to the clinically used 36-mer peptide T20. Furthermore, combining hCS6ERE with a fusion inhibitor having a different target site, such as HP23, produced synergistic anti-HIV-1 activity. Collectively, our study offers new insight into the design of anti-HIV peptides with short sequences.
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Affiliation(s)
- Guangpeng Meng
- Key Laboratory of Structure-Based Drug Design & Discovery of the Ministry of Education , Shenyang Pharmaceutical University , Shenyang 110016 , China
| | - Jing Pu
- Key Laboratory of Medical Molecular Virology of (MOE/NHC/CAMS), School of Basic Medical Sciences & Shanghai Public Health Clinical Center , Fudan University , 131 Dong An Road , Shanghai 200032 , China
| | - Yue Li
- Key Laboratory of Structure-Based Drug Design & Discovery of the Ministry of Education , Shenyang Pharmaceutical University , Shenyang 110016 , China
| | - Aixin Han
- State Key Laboratory of Toxicology and Medical Countermeasures , Beijing Institute of Pharmacology and Toxicology , 27 Tai-Ping Road , Beijing 100850 , China
| | - Yangli Tian
- State Key Laboratory of Toxicology and Medical Countermeasures , Beijing Institute of Pharmacology and Toxicology , 27 Tai-Ping Road , Beijing 100850 , China
| | - Wei Xu
- Key Laboratory of Medical Molecular Virology of (MOE/NHC/CAMS), School of Basic Medical Sciences & Shanghai Public Health Clinical Center , Fudan University , 131 Dong An Road , Shanghai 200032 , China
| | - Tianhong Zhang
- State Key Laboratory of Toxicology and Medical Countermeasures , Beijing Institute of Pharmacology and Toxicology , 27 Tai-Ping Road , Beijing 100850 , China
| | - Xue Li
- State Key Laboratory of Toxicology and Medical Countermeasures , Beijing Institute of Pharmacology and Toxicology , 27 Tai-Ping Road , Beijing 100850 , China
| | - Lu Lu
- Key Laboratory of Medical Molecular Virology of (MOE/NHC/CAMS), School of Basic Medical Sciences & Shanghai Public Health Clinical Center , Fudan University , 131 Dong An Road , Shanghai 200032 , China
| | - Chao Wang
- State Key Laboratory of Toxicology and Medical Countermeasures , Beijing Institute of Pharmacology and Toxicology , 27 Tai-Ping Road , Beijing 100850 , China
| | - Shibo Jiang
- Key Laboratory of Medical Molecular Virology of (MOE/NHC/CAMS), School of Basic Medical Sciences & Shanghai Public Health Clinical Center , Fudan University , 131 Dong An Road , Shanghai 200032 , China.,Lindsley F. Kimball Research Institute , New York Blood Center , 310 East 67th Street , New York , New York 10065 , United States
| | - Keliang Liu
- Key Laboratory of Structure-Based Drug Design & Discovery of the Ministry of Education , Shenyang Pharmaceutical University , Shenyang 110016 , China.,State Key Laboratory of Toxicology and Medical Countermeasures , Beijing Institute of Pharmacology and Toxicology , 27 Tai-Ping Road , Beijing 100850 , China
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2
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Eggink D, Bontjer I, de Taeye SW, Langedijk JPM, Berkhout B, Sanders RW. HIV-1 anchor inhibitors and membrane fusion inhibitors target distinct but overlapping steps in virus entry. J Biol Chem 2019; 294:5736-5746. [PMID: 30696772 PMCID: PMC6463712 DOI: 10.1074/jbc.ra119.007360] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Revised: 01/25/2019] [Indexed: 12/03/2022] Open
Abstract
HIV-1 entry into cells is mediated by the envelope glycoprotein (Env) and represents an attractive target for therapeutic intervention. Two drugs that inhibit HIV entry are approved for clinical use: the membrane fusion-inhibitor T20 (Fuzeon, enfuvirtide) and the C-C chemokine receptor type 5 (CCR5) blocker maraviroc (Selzentry). Another class of entry inhibitors supposedly target the fusion peptide (FP) and are termed anchor inhibitors. These include the VIRIP peptide and VIRIP derivatives such as VIR165, VIR353, and VIR576. Here, we investigated the mechanism of inhibition by VIR165. We show that substitutions within the FP modulate sensitivity to VIR165, consistent with the FP being the drug target. Our results also revealed that VIR165 acts during an intermediate post-CD4–binding entry step that is overlapping but not identical to the step inhibited by fusion inhibitors such as T20. We found that some but not all resistance mutations to heptad repeat 2 (HR2)-targeting fusion inhibitors can provide cross-resistance to VIR165. In contrast, resistance mutations in the HR1-binding site for the fusion inhibitors did not cause cross-resistance to VIR165. However, Env with mutations located outside this binding site and thought to affect fusion kinetics, exhibited decreased sensitivity to VIR165. Although we found a strong correlation between Env stability and resistance to HR2-based fusion inhibitors, such correlation was not observed for Env stability and VIR165 resistance. We conclude that VIRIP analogs target the FP during an intermediate, post-CD4–binding entry step that overlaps with but is distinct from the step(s) inhibited by HR2-based fusion inhibitors.
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Affiliation(s)
- Dirk Eggink
- From the Laboratory of Experimental Virology, Department of Medical Microbiology, Amsterdam University Medical Centers (Amsterdam UMC), Location AMC, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
| | - Ilja Bontjer
- From the Laboratory of Experimental Virology, Department of Medical Microbiology, Amsterdam University Medical Centers (Amsterdam UMC), Location AMC, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
| | - Steven W de Taeye
- From the Laboratory of Experimental Virology, Department of Medical Microbiology, Amsterdam University Medical Centers (Amsterdam UMC), Location AMC, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
| | | | - Ben Berkhout
- From the Laboratory of Experimental Virology, Department of Medical Microbiology, Amsterdam University Medical Centers (Amsterdam UMC), Location AMC, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
| | - Rogier W Sanders
- From the Laboratory of Experimental Virology, Department of Medical Microbiology, Amsterdam University Medical Centers (Amsterdam UMC), Location AMC, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands; the Department of Microbiology and Immunology, Weill Medical College of Cornell University, New York, New York 10065.
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3
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Zhang R, Verkoczy L, Wiehe K, Munir Alam S, Nicely NI, Santra S, Bradley T, Pemble CW, Zhang J, Gao F, Montefiori DC, Bouton-Verville H, Kelsoe G, Larimore K, Greenberg PD, Parks R, Foulger A, Peel JN, Luo K, Lu X, Trama AM, Vandergrift N, Tomaras GD, Kepler TB, Moody MA, Liao HX, Haynes BF. Initiation of immune tolerance-controlled HIV gp41 neutralizing B cell lineages. Sci Transl Med 2017; 8:336ra62. [PMID: 27122615 DOI: 10.1126/scitranslmed.aaf0618] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Accepted: 03/28/2016] [Indexed: 01/09/2023]
Abstract
Development of an HIV vaccine is a global priority. A major roadblock to a vaccine is an inability to induce protective broadly neutralizing antibodies (bnAbs). HIV gp41 bnAbs have characteristics that predispose them to be controlled by tolerance. We used gp41 2F5 bnAb germline knock-in mice and macaques vaccinated with immunogens reactive with germline precursors to activate neutralizing antibodies. In germline knock-in mice, bnAb precursors were deleted, with remaining anergic B cells capable of being activated by germline-binding immunogens to make gp41-reactive immunoglobulin M (IgM). Immunized macaques made B cell clonal lineages targeted to the 2F5 bnAb epitope, but 2F5-like antibodies were either deleted or did not attain sufficient affinity for gp41-lipid complexes to achieve the neutralization potency of 2F5. Structural analysis of members of a vaccine-induced antibody lineage revealed that heavy chain complementarity-determining region 3 (HCDR3) hydrophobicity was important for neutralization. Thus, gp41 bnAbs are controlled by immune tolerance, requiring vaccination strategies to transiently circumvent tolerance controls.
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Affiliation(s)
- Ruijun Zhang
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA
| | - Laurent Verkoczy
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA. Department of Pathology, Duke University School of Medicine, Durham, NC 27710, USA. Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA
| | - Kevin Wiehe
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA. Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA
| | - S Munir Alam
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA. Department of Pathology, Duke University School of Medicine, Durham, NC 27710, USA. Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA
| | - Nathan I Nicely
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA
| | - Sampa Santra
- Beth Israel Deaconess Medical Center, Boston, MA 02215, USA
| | - Todd Bradley
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA. Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA
| | - Charles W Pemble
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA
| | - Jinsong Zhang
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA
| | - Feng Gao
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA. Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA
| | - David C Montefiori
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA. Department of Surgery, Duke University School of Medicine, Durham, NC 27710, USA
| | | | - Garnett Kelsoe
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA. Department of Immunology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Kevin Larimore
- Fred Hutchinson Cancer Research Center, University of Washington, Seattle, WA 98109, USA
| | - Phillip D Greenberg
- Fred Hutchinson Cancer Research Center, University of Washington, Seattle, WA 98109, USA
| | - Robert Parks
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA
| | - Andrew Foulger
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA
| | - Jessica N Peel
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA
| | - Kan Luo
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA
| | - Xiaozhi Lu
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA
| | - Ashley M Trama
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA
| | - Nathan Vandergrift
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA. Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA
| | - Georgia D Tomaras
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA. Department of Surgery, Duke University School of Medicine, Durham, NC 27710, USA
| | - Thomas B Kepler
- Department of Microbiology, Boston University School of Medicine, Boston, MA 02118, USA
| | - M Anthony Moody
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA. Department of Immunology, Duke University School of Medicine, Durham, NC 27710, USA. Department of Pediatrics, Duke University School of Medicine, Durham, NC 27710, USA
| | - Hua-Xin Liao
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA. Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA.
| | - Barton F Haynes
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA. Department of Pathology, Duke University School of Medicine, Durham, NC 27710, USA. Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA.
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4
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Antigenic and immunosuppressive properties of a trimeric recombinant transmembrane envelope protein gp41 of HIV-1. PLoS One 2017; 12:e0173454. [PMID: 28282446 PMCID: PMC5345815 DOI: 10.1371/journal.pone.0173454] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Accepted: 02/22/2017] [Indexed: 02/07/2023] Open
Abstract
The transmembrane envelope (TM) protein gp41 of the human immunodeficiency virus—1 (HIV-1) plays an important role during virus infection inducing the fusion of the viral and cellular membranes. In addition, there are indications that the TM protein plays a role in the immunopathogenesis leading to the acquired immunodeficiency syndrome (AIDS). Inactivated virus particles and recombinant gp41 have been reported to inhibit lymphocyte proliferation, as well as to alter cytokine release and gene expression. The same was shown for a peptide corresponding to a highly conserved domain of all retroviral TM proteins, the immunosuppressive domain. Due to its propensity to aggregate and to be expressed at low levels, studies comprising authentic gp41 produced in eukaryotic cells are extremely rare. Here we describe the production of a secreted, soluble recombinant gp41 in 293 cells. The antigen was purified to homogeneity and characterised thoroughly by various biochemical and immunological methods. It was shown that the protein was glycosylated and assembled into trimers. Binding studies by ELISA and surface plasmon resonance using conformation-specific monoclonal antibodies implied a six-helix bundle conformation. The low binding of broadly neutralising antibodies (bnAb) directed against the membrane proximal external region (MPER) suggested that this gp41 is probably not suited as vaccine to induce such bnAb. Purified gp41 bound to monocytes and to a lesser extent to lymphocytes and triggered the production of specific cytokines when added to normal peripheral blood mononuclear cells. In addition, gp41 expressed on target cells inhibited the antigen-specific response of murine CD8+ T cells by drastically impairing their IFNγ production. To our knowledge, this is the first comprehensive analysis of a gp41 produced in eukaryotic cells including its immunosuppressive properties. Our data provide another line of evidence that gp41 might be directly involved in HIV-1 immunopathogenesis through modulation of the cytokine release and active inhibition of immune responses.
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5
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Louis JM, Baber JL, Clore GM. The C34 Peptide Fusion Inhibitor Binds to the Six-Helix Bundle Core Domain of HIV-1 gp41 by Displacement of the C-Terminal Helical Repeat Region. Biochemistry 2015; 54:6796-805. [PMID: 26506247 DOI: 10.1021/acs.biochem.5b01021] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The conformational transition of the core domain of HIV-1 gp41 from a prehairpin intermediate to a six-helix bundle is responsible for virus-cell fusion. Several inhibitors which target the N-heptad repeat helical coiled-coil trimer that is fully accessible in the prehairpin intermediate have been designed. One such inhibitor is the peptide C34 derived from the C-heptad repeat of gp41 that forms the exterior of the six-helix bundle. Here, using a variety of biophysical techniques, including dye tagging, size-exclusion chromatography combined with multiangle light scattering, double electron-electron resonance EPR spectroscopy, and circular dichroism, we investigate the binding of C34 to two six-helix bundle mimetics comprising N- and C-heptad repeats either without (core(SP)) or with (core(S)) a short spacer connecting the two. In the case of core(SP), C34 directly exchanges with the C-heptad repeat. For core(S), up to two molecules of C34 bind the six-helix bundle via displacement of the C-heptad repeat. These results suggest that fusion inhibitors such as C34 can target a continuum of transitioning conformational states from the prehairpin intermediate to the six-helix bundle prior to the occurrence of irreversible fusion of viral and target cell membranes.
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Affiliation(s)
- John M Louis
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health , Bethesda, Maryland 20892-0520, United States
| | - James L Baber
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health , Bethesda, Maryland 20892-0520, United States
| | - G Marius Clore
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health , Bethesda, Maryland 20892-0520, United States
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Louis JM, Aniana A, Lohith K, Sayer JM, Roche J, Bewley CA, Clore GM. Binding of HIV-1 gp41-directed neutralizing and non-neutralizing fragment antibody binding domain (Fab) and single chain variable fragment (ScFv) antibodies to the ectodomain of gp41 in the pre-hairpin and six-helix bundle conformations. PLoS One 2014; 9:e104683. [PMID: 25105806 PMCID: PMC4126735 DOI: 10.1371/journal.pone.0104683] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Accepted: 07/16/2014] [Indexed: 11/25/2022] Open
Abstract
We previously reported a series of antibodies, in fragment antigen binding domain (Fab) formats, selected from a human non-immune phage library, directed against the internal trimeric coiled-coil of the N-heptad repeat (N-HR) of HIV-1 gp41. Broadly neutralizing antibodies from that series bind to both the fully exposed N-HR trimer, representing the pre-hairpin intermediate state of gp41, and to partially-exposed N-HR helices within the context of the gp41 six-helix bundle. While the affinities of the Fabs for pre-hairpin intermediate mimetics vary by only 2 to 20-fold between neutralizing and non-neutralizing antibodies, differences in inhibition of viral entry exceed three orders of magnitude. Here we compare the binding of neutralizing (8066) and non-neutralizing (8062) antibodies, differing in only four positions within the CDR-H2 binding loop, in Fab and single chain variable fragment (ScFv) formats, to several pre-hairpin intermediate and six-helix bundle constructs of gp41. Residues 56 and 58 of the mini-antibodies are shown to be crucial for neutralization activity. There is a large differential (≥150-fold) in binding affinity between neutralizing and non-neutralizing antibodies to the six-helix bundle of gp41 and binding to the six-helix bundle does not involve displacement of the outer C-terminal helices of the bundle. The binding stoichiometry is one six-helix bundle to one Fab or three ScFvs. We postulate that neutralization by the 8066 antibody is achieved by binding to a continuum of states along the fusion pathway from the pre-hairpin intermediate all the way to the formation of the six-helix bundle, but prior to irreversible fusion between viral and cellular membranes.
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Affiliation(s)
- John M. Louis
- Laboratories of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
- * E-mail: (JML); (GMC)
| | - Annie Aniana
- Laboratories of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Katheryn Lohith
- Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Jane M. Sayer
- Laboratories of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Julien Roche
- Laboratories of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Carole A. Bewley
- Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - G. Marius Clore
- Laboratories of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
- * E-mail: (JML); (GMC)
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Demirkhanyan L, Marin M, Lu W, Melikyan GB. Sub-inhibitory concentrations of human α-defensin potentiate neutralizing antibodies against HIV-1 gp41 pre-hairpin intermediates in the presence of serum. PLoS Pathog 2013; 9:e1003431. [PMID: 23785290 PMCID: PMC3681749 DOI: 10.1371/journal.ppat.1003431] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Accepted: 05/02/2013] [Indexed: 12/13/2022] Open
Abstract
Human defensins are at the forefront of the host responses to HIV and other pathogens in mucosal tissues. However, their ability to inactivate HIV in the bloodstream has been questioned due to the antagonistic effect of serum. In this study, we have examined the effect of sub-inhibitory concentrations of human α-defensin HNP-1 on the kinetics of early steps of fusion between HIV-1 and target cells in the presence of serum. Direct measurements of HIV-cell fusion using an enzymatic assay revealed that, in spite of the modest effect on the extent of fusion, HNP-1 prolonged the exposure of functionally important transitional epitopes of HIV-1 gp41 on the cell surface. The increased lifetime of gp41 intermediates in the presence of defensin was caused by a delay in the post-coreceptor binding steps of HIV-1 entry that correlated with the marked enhancement of the virus' sensitivity to neutralizing anti-gp41 antibodies. By contrast, the activity of antibodies to gp120 was not affected. HNP-1 appeared to specifically potentiate antibodies and peptides targeting the first heptad repeat domain of gp41, while its effect on inhibitors and antibodies to other gp41 domains was less prominent. Sub-inhibitory concentrations of HNP-1 also promoted inhibition of HIV-1 entry into peripheral blood mononuclear cells by antibodies and, more importantly, by HIV-1 immune serum. Our findings demonstrate that: (i) sub-inhibitory doses of HNP-1 potently enhance the activity of a number of anti-gp41 antibodies and peptide inhibitors, apparently by prolonging the lifetime of gp41 intermediates; and (ii) the efficiency of HIV-1 fusion inhibitors and neutralizing antibodies is kinetically restricted. This study thus reveals an important role of α-defensin in enhancing adaptive immune responses to HIV-1 infection and suggests future strategies to augment these responses. Human neutrophil peptide 1 (HNP-1) is a small cationic peptide that can directly block HIV-1 entry in the absence of serum. However, since serum attenuates the anti-HIV activity of this peptide, HNP-1 is unlikely to inhibit infection in the bloodstream. Here, we demonstrate that sub-inhibitory doses of HNP-1 in the presence of serum can strongly enhance the activity of neutralizing antibodies and inhibitors targeting transiently exposed intermediate conformations of HIV-1 gp41. HNP-1 appears to exert this effect by delaying post-coreceptor binding steps of fusion and thereby prolonging the exposure of gp41 intermediates. These results imply that the HIV-1 fusion kinetics is an important determinant of sensitivity to neutralizing antibodies and peptides against transiently exposed functional domains of gp41. The surprising synergy between sub-inhibitory concentrations of HNP-1 and anti-gp41 antibodies suggests new strategies to sensitize the virus to circulating antibodies by developing compounds that prolong the exposure of conserved gp41 epitopes on the cell surface.
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Affiliation(s)
- Lusine Demirkhanyan
- Division of Pediatric Infectious Diseases, Emory University Children's Center, Atlanta, Georgia, United States of America
| | - Mariana Marin
- Division of Pediatric Infectious Diseases, Emory University Children's Center, Atlanta, Georgia, United States of America
| | - Wuyuan Lu
- Institute of Human Virology and Department of Biochemistry, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Gregory B. Melikyan
- Division of Pediatric Infectious Diseases, Emory University Children's Center, Atlanta, Georgia, United States of America
- Children's Healthcare of Atlanta, Atlanta, Georgia, United States of America
- * E-mail:
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8
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Antibody-DEPENDENT, FcγRI-mediated neutralization of HIV-1 in TZM-bl cells occurs independently of phagocytosis. J Virol 2013; 87:5287-90. [PMID: 23408628 DOI: 10.1128/jvi.00278-13] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We previously showed that expression of human FcγRI on TZM-bl cells potentiates neutralization by gp41 membrane-proximal external region (MPER)-specific antibodies. Here we show that lysosomotropic reagents known to block phagocytosis do not diminish this effect. We also show that FcγRI occasionally potentiates neutralization by antibodies against the V3 loop of gp120 and cluster I of gp41. We conclude that FcγRI provides a kinetic advantage for neutralizing antibodies against partially cryptic epitopes independent of phagocytosis.
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9
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Chen W, Dimitrov DS. Monoclonal antibody-based candidate therapeutics against HIV type 1. AIDS Res Hum Retroviruses 2012; 28:425-34. [PMID: 21827278 DOI: 10.1089/aid.2011.0226] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Treatment of HIV-1 infection has been highly successful with small molecule drugs. However, resistance still develops. In addition, long-term use can lead to toxicity with unpredictable effects on health. Finally, current drugs do not lead to HIV-1 eradication. The presence of the virus leads to chronic inflammation, which can result in increased morbidity and mortality after prolonged periods of infection. Monoclonal antibodies (mAbs) have been highly successful during the past two decades for therapy of many diseases, primarily cancers and immune disorders. They are relatively safe, especially human mAbs that have evolved in humans at high concentrations to fight diseases and long-term use may not lead to toxicities. Several broadly neutralizing mAbs (bnmAbs) against HIV-1 can protect animals but are not effective when used for therapy of an established infection. We have hypothesized that HIV-1 has evolved strategies to effectively escape neutralization by full-size antibodies in natural infections but not by smaller antibody fragments. Therefore, a promising direction of research is to discover and exploit antibody fragments as potential candidate therapeutics against HIV-1. Here we review several bnmAbs and engineered antibody domains (eAds), their in vitro and in vivo antiviral efficacy, mechanisms used by HIV-1 to escape them, and strategies that could be effective to develop more powerful mAb-based HIV-1 therapeutics.
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Affiliation(s)
- Weizao Chen
- Protein Interactions Group, Center for Cancer Research Nanobiology Program, National Cancer Institute (NCI)-Frederick, National Institutes of Health (NIH), Frederick, Maryland
| | - Dimiter S. Dimitrov
- Protein Interactions Group, Center for Cancer Research Nanobiology Program, National Cancer Institute (NCI)-Frederick, National Institutes of Health (NIH), Frederick, Maryland
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10
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Delhalle S, Schmit JC, Chevigné A. Phages and HIV-1: from display to interplay. Int J Mol Sci 2012; 13:4727-4794. [PMID: 22606007 PMCID: PMC3344243 DOI: 10.3390/ijms13044727] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2012] [Revised: 03/26/2012] [Accepted: 03/30/2012] [Indexed: 11/16/2022] Open
Abstract
The complex hide-and-seek game between HIV-1 and the host immune system has impaired the development of an efficient vaccine. In addition, the high variability of the virus impedes the long-term control of viral replication by small antiviral drugs. For more than 20 years, phage display technology has been intensively used in the field of HIV-1 to explore the epitope landscape recognized by monoclonal and polyclonal HIV-1-specific antibodies, thereby providing precious data about immunodominant and neutralizing epitopes. In parallel, biopanning experiments with various combinatorial or antibody fragment libraries were conducted on viral targets as well as host receptors to identify HIV-1 inhibitors. Besides these applications, phage display technology has been applied to characterize the enzymatic specificity of the HIV-1 protease. Phage particles also represent valuable alternative carriers displaying various HIV-1 antigens to the immune system and eliciting antiviral responses. This review presents and summarizes the different studies conducted with regard to the nature of phage libraries, target display mode and biopanning procedures.
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Affiliation(s)
- Sylvie Delhalle
- Laboratory of Retrovirology, CRP-Sante, 84, Val Fleuri, L-1526 Luxembourg, Luxembourg; E-Mails: (J.-C.S.); (A.C.)
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +352-26970211; Fax: +352-26970221
| | - Jean-Claude Schmit
- Laboratory of Retrovirology, CRP-Sante, 84, Val Fleuri, L-1526 Luxembourg, Luxembourg; E-Mails: (J.-C.S.); (A.C.)
- Service National des Maladies Infectieuses, Centre Hospitalier Luxembourg, 4, rue E. Barblé, L-1210 Luxembourg, Luxembourg
| | - Andy Chevigné
- Laboratory of Retrovirology, CRP-Sante, 84, Val Fleuri, L-1526 Luxembourg, Luxembourg; E-Mails: (J.-C.S.); (A.C.)
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11
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Dogo-Isonagie C, Lam S, Gustchina E, Acharya P, Yang Y, Shahzad-ul-Hussan S, Clore GM, Kwong PD, Bewley CA. Peptides from second extracellular loop of C-C chemokine receptor type 5 (CCR5) inhibit diverse strains of HIV-1. J Biol Chem 2012; 287:15076-86. [PMID: 22403408 DOI: 10.1074/jbc.m111.332361] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
To initiate HIV entry, the HIV envelope protein gp120 must engage its primary receptor CD4 and a coreceptor CCR5 or CXCR4. In the absence of a high resolution structure of a gp120-coreceptor complex, biochemical studies of CCR5 have revealed the importance of its N terminus and second extracellular loop (ECL2) in binding gp120 and mediating viral entry. Using a panel of synthetic CCR5 ECL2-derived peptides, we show that the C-terminal portion of ECL2 (2C, comprising amino acids Cys-178 to Lys-191) inhibit HIV-1 entry of both CCR5- and CXCR4-using isolates at low micromolar concentrations. In functional viral assays, these peptides inhibited HIV-1 entry in a CD4-independent manner. Neutralization assays designed to measure the effects of CCR5 ECL2 peptides when combined with either with the small molecule CD4 mimetic NBD-556, soluble CD4, or the CCR5 N terminus showed additive inhibition for each, indicating that ECL2 binds gp120 at a site distinct from that of N terminus and acts independently of CD4. Using saturation transfer difference NMR, we determined the region of CCR5 ECL2 used for binding gp120, showed that it can bind to gp120 from both R5 and X4 isolates, and demonstrated that the peptide interacts with a CD4-gp120 complex in a similar manner as to gp120 alone. As the CCR5 N terminus-gp120 interactions are dependent on CD4 activation, our data suggest that gp120 has separate binding sites for the CCR5 N terminus and ECL2, the ECL2 binding site is present prior to CD4 engagement, and it is conserved across CCR5- and CXCR4-using strains. These peptides may serve as a starting point for the design of inhibitors with broad spectrum anti-HIV activity.
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Affiliation(s)
- Cajetan Dogo-Isonagie
- Laboratory of Bioorganic Chemistry, NIAID, National Institutes of Health, Bethesda, Maryland 20892, USA
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12
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Binding of anti-membrane-proximal gp41 monoclonal antibodies to CD4-liganded and -unliganded human immunodeficiency virus type 1 and simian immunodeficiency virus virions. J Virol 2011; 86:1820-31. [PMID: 22090143 DOI: 10.1128/jvi.05489-11] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
The broadly neutralizing monoclonal antibodies (MAbs) 4E10, 2F5, and Z13e1 target membrane-proximal external region (MPER) epitopes of HIV-1 gp41 in a manner that remains controversial. The requirements for initial lipid bilayer binding and/or CD4 ligation have been proposed. To further investigate these issues, we probed for binding of these MAbs to human immunodeficiency virus type 1 (HIV-1) and simian immunodeficiency virus (SIV) virions with protein A-conjugated gold (PAG) nanoparticles using negative-stain electron microscopy. We found moderate levels of PAG associated with unliganded HIV-1 and SIV virions incubated with the three MAbs. Significantly higher levels of PAG were associated with CD4-liganded HIV-1 (epitope-positive) but not SIV (epitope-negative) virions. A chimeric SIV virion displaying the HIV-1 4E10 epitope also showed significantly higher PAG association after CD4 ligation and incubation with 4E10. MAbs accumulated rapidly on CD4-liganded virions and slowly on unliganded virions, although both reached similar levels in time. Anti-MPER epitope-specific binding was stable to washout. Virions incubated with an irrelevant MAb or CD4-only (no MAb) showed negligible PAG association, as did a vesicle-rich fraction devoid of virions. Preincubation with Fab 4E10 inhibited both specific and nonspecific 4E10 IgG binding. Our data provide evidence for moderate association of anti-MPER MAbs to viral surfaces but not lipid vesicles, even in the absence of cognate epitopes. Significantly greater MAb interaction occurs in epitope-positive virions following long incubation or CD4 ligation. These findings are consistent with a two-stage binding model where these anti-MPER MAbs bind first to the viral lipid bilayer and then to the MPER epitopes following spontaneous or induced exposure.
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13
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Melikyan GB. Membrane fusion mediated by human immunodeficiency virus envelope glycoprotein. CURRENT TOPICS IN MEMBRANES 2011; 68:81-106. [PMID: 21771496 DOI: 10.1016/b978-0-12-385891-7.00004-0] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Gregory B Melikyan
- Department of Pediatrics, Infectious Diseases, Emory University, Atlanta, GA, USA
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14
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Gustchina E, Li M, Louis JM, Anderson DE, Lloyd J, Frisch C, Bewley CA, Gustchina A, Wlodawer A, Clore GM. Structural basis of HIV-1 neutralization by affinity matured Fabs directed against the internal trimeric coiled-coil of gp41. PLoS Pathog 2010; 6:e1001182. [PMID: 21085615 PMCID: PMC2978731 DOI: 10.1371/journal.ppat.1001182] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2010] [Accepted: 10/06/2010] [Indexed: 01/22/2023] Open
Abstract
The conserved internal trimeric coiled-coil of the N-heptad repeat (N-HR) of HIV-1 gp41 is transiently exposed during the fusion process by forming a pre-hairpin intermediate, thus representing an attractive target for the design of fusion inhibitors and neutralizing antibodies. In previous studies we reported a series of broadly neutralizing mini-antibodies derived from a synthetic naïve human combinatorial antibody library by panning against a mimetic of the trimeric N-HR coiled coil, followed by affinity maturation using targeted diversification of the CDR-H2 loop. Here we report crystal structures of the N-HR mimetic 5-Helix with two Fabs that represent the extremes of this series: Fab 8066 is broadly neutralizing across a wide panel of B and C type HIV-1 viruses, whereas Fab 8062 is non-neutralizing. The crystal structures reveal important differences in the conformations of the CDR-H2 loops in the complexes that propagate into other regions of the antigen-antibody interface, and suggest that both neutralization properties and affinity for the target can be attributed, at least in part, to the differences in the interactions of the CDR-H2 loops with the antigen. Furthermore, modeling of the complex of an N-HR trimer with three Fabs suggests that the CDR-H2 loop may be involved in close intermolecular contacts between neighboring antibody molecules, and that such contacts may hinder the formation of complexes between the N-HR trimer and more than one antibody molecule depending on the conformation of the bound CDR-H2 loop which is defined by its interactions with antigen. Comparison with the crystal structure of the complex of 5-Helix with another neutralizing monoclonal antibody known as D5, derived using an entirely different antibody library and panning procedure, reveals remarkable convergence in the optimal sequence and conformation of the CDR-H2 loop.
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Affiliation(s)
- Elena Gustchina
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Mi Li
- Protein Structure Section, Macromolecular Crystallography Laboratory, National Cancer Institute, Frederick, Maryland, United States of America
- Basic Research Program, SAIC-Frederick, Frederick, Maryland, United States of America
| | - John M. Louis
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - D. Eric Anderson
- Proteomics and Mass Spectrometry Facility, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - John Lloyd
- Proteomics and Mass Spectrometry Facility, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | | | - Carole A. Bewley
- Laboratory of Biorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Alla Gustchina
- Protein Structure Section, Macromolecular Crystallography Laboratory, National Cancer Institute, Frederick, Maryland, United States of America
| | - Alexander Wlodawer
- Protein Structure Section, Macromolecular Crystallography Laboratory, National Cancer Institute, Frederick, Maryland, United States of America
| | - G. Marius Clore
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
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15
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Hertje M, Zhou M, Dietrich U. Inhibition of HIV-1 Entry: Multiple Keys to Close the Door. ChemMedChem 2010; 5:1825-35. [DOI: 10.1002/cmdc.201000292] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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16
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Plaza A, Bifulco G, Masullo M, Lloyd JR, Keffer JL, Colin PL, Hooper JNA, Bell LJ, Bewley CA. Mutremdamide A and koshikamides C-H, peptide inhibitors of HIV-1 entry from different Theonella species. J Org Chem 2010; 75:4344-55. [PMID: 20402515 PMCID: PMC3272276 DOI: 10.1021/jo100076g] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A new sulfated cyclic depsipeptide, termed mutremdamide A, and six new highly N-methylated peptides, termed koshikamides C-H, were isolated from different deep-water specimens of Theonella swinhoei and Theonella cupola. Their structures were determined using extensive 2D NMR, ESI, or CDESI and QTOF-MS/MS experiments and absolute configurations established by quantum mechanical calculations, advanced Marfey's method, and chiral HPLC. Mutremdamide A displays a rare 2-amino-3-(2-hydroxyphenyl)propanoic acid and a new N(delta)-carbamoyl-beta-sulfated asparagine. Koshikamides C-E are linear undecapeptides, and koshikamides F-H are 17-residue depsipeptides containing a 10-residue macrolactone. Koshikamides F and G differ from B and H in part by the presence of the conjugated unit 2-(3-amino-5-oxopyrrolidin-2-ylidene)propanoic acid. Cyclic koshikamides F and H inhibited HIV-1 entry at low micromolar concentrations while their linear counterparts were inactive. The Theonella collections studied here are distinguished by co-occurrence of mutremdamide A, koshikamides, and theonellamides, the combination of which appears to define a new Theonella chemotype that can be found in deeper waters.
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Affiliation(s)
- Alberto Plaza
- Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892
| | - Giuseppe Bifulco
- Dipartimento di Scienze Farmaceutiche, University of Salerno, Via Ponte Don Melillo, 84084 Fisciano, Salerno, Italy
| | - Milena Masullo
- Dipartimento di Scienze Farmaceutiche, University of Salerno, Via Ponte Don Melillo, 84084 Fisciano, Salerno, Italy
| | - John R. Lloyd
- Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892
| | - Jessica L. Keffer
- Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892
| | | | - John N. A. Hooper
- Queensland Museum, P.O. Box 3300, South Brisbane, Qld 4101, Australia
| | - Lori J. Bell
- Coral Reef Research Foundation, Republic of Palau
| | - Carole A. Bewley
- Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892
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17
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Plaza A, Keffer JL, Lloyd JR, Colin PL, Bewley CA. Paltolides A--C, anabaenopeptin-type peptides from the palau sponge Theonella swinhoei. JOURNAL OF NATURAL PRODUCTS 2010; 73:485-488. [PMID: 20078073 PMCID: PMC2885440 DOI: 10.1021/np900728x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Three new anabaenopeptin-like peptides, named paltolides A-C, were isolated from a deep-water specimen of the marine sponge Theonella swinhoei from Palau. Paltolides belong to a rare subgroup of sponge-derived anabaenopeptins that have in common a C-terminal tryptophan residue linked to the epsilon-amine of a lysine bearing a d configuration. The structures of paltolides A-C were determined by NMR and tandem MS techniques. Paltolide A is the first anabaenopeptin structure where a non-N-methylated amino acid precedes the C-terminal residue.
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Affiliation(s)
| | | | | | | | - Carole A. Bewley
- To whom correspondence should be addressed. Tel.: (301) 594-5187. Fax (301) 402-4182.
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18
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Prolonged exposure of the HIV-1 gp41 membrane proximal region with L669S substitution. Proc Natl Acad Sci U S A 2010; 107:5972-7. [PMID: 20231447 DOI: 10.1073/pnas.0912381107] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The conserved membrane-proximal external region (MPER) of HIV-1 envelope is a target for the rare broadly neutralizing 2F5, Z13, and 4E10 monoclonal antibodies (mAbs). One strategy to elicit such antibodies is to design an immunogen with increased exposure of the 2F5 and 4E10 mAb epitopes. In this study we characterize a single leucine to serine substitution at position 669 (L669S) in the gp41 Env MPER that confers >250-fold more neutralization sensitivity to 2F5 and 4E10 mAbs than does the wild-type gp41 sequence. On synthetic liposomes, increased solvent exposure of MPER tryptophan residues and stable docking of 2F5 and 4E10 mAbs to mutant MPER peptide liposomes indicate more favorable membrane orientation of MPER neutralizing epitopes with L669S substitution. The time during which virus is sensitive to 2F5 mAb-mediated neutralization is approximately 3-fold longer when the mutation is present. These data suggest that a major contribution to the L669S mutant virus phenotype of enhanced susceptibility to MPER mAbs is prolonged exposure of the MPER neutralizing epitope during viral entry.
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19
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Morozov V, Morozov A, Lagaye S. Short communication: Simultaneous substitutions of V38M and N43T-N44K in the gp41 heptad repeat 1 (HR1) disrupt HIV type 1 gPr160 endoproteolytic cleavage (*). AIDS Res Hum Retroviruses 2010; 26:73-7. [PMID: 20055586 DOI: 10.1089/aid.2009.0079] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
We cloned and sequenced gp41 HIV-1 from plasma of AIDS patients under HAART and T-20 (enfuvirtide, Fuzeon) therapy and revealed several T-20 resistance-associated mutations. Two mutations, a single V38A and a double N43T-N44K were the most frequent; however, they were not found together in one clone. We anticipated that simultaneous mutations of these three residues might play a vital role in the viral life cycle. To address this problem, we introduced N43T-N44K and V38M + N43T-N44K substitutions to a cloned gp41 and introduced modified gp41 into the pNL4-3 molecular clone. HEK293T cells were transfected with the obtained vectors and released viruses were examined for reverse transcriptase (RT) activity, infectivity on reporter TZM-bl cells, and in Western blotting. Nearly equal RT activity was demonstrated in viruses with and without mutations. However, viruses with the V38M + N43T-N44K mutations were not infectious and, as shown by Western blotting, gPr160 cleavage was impaired. These data suggest that V38M + N43T-N44K mutations perturbed the natural conformation of gPr160 in a way that access of furin to the cleavage site (REKR) was blocked. Therefore, the residues V38 + N43-N44 retain the gPr160 conformation in proximity to the furin cleavage site and, as a consequence, are critical for virus infectivity. These data may explain why viruses with V38M + N43T-N44K mutations were not previously detected in the plasma of T-20-experienced patients.
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Affiliation(s)
- V.A. Morozov
- Institute of Human Virology, School of Medicine, University of Maryland, Baltimore, Maryland 21201
- Robert Koch-Institute, 13353 Berlin, Germany
| | - A.V. Morozov
- Institute of Human Virology, School of Medicine, University of Maryland, Baltimore, Maryland 21201
- W.A. Engelhardt Institute of Molecular Biology RAS, Moscow, Russia
| | - S. Lagaye
- Institut Cochin, UMR 8104 CNRS, U567 INSERM, Université Paris Descartes, 75014 Paris, France
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20
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Binding of a potent small-molecule inhibitor of six-helix bundle formation requires interactions with both heptad-repeats of the RSV fusion protein. Proc Natl Acad Sci U S A 2009; 107:308-13. [PMID: 19966279 DOI: 10.1073/pnas.0910108106] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Six-helix bundle (6HB) formation is an essential step for many viruses that rely on a class I fusion protein to enter a target cell and initiate replication. Because the binding modes of small molecule inhibitors of 6HB formation are largely unknown, precisely how they disrupt 6HB formation remains unclear, and structure-based design of improved inhibitors is thus seriously hampered. Here we present the high resolution crystal structure of TMC353121, a potent inhibitor of respiratory syncytial virus (RSV), bound at a hydrophobic pocket of the 6HB formed by amino acid residues from both HR1 and HR2 heptad-repeats. Binding of TMC353121 stabilizes the interaction of HR1 and HR2 in an alternate conformation of the 6HB, in which direct binding interactions are formed between TMC353121 and both HR1 and HR2. Rather than completely preventing 6HB formation, our data indicate that TMC353121 inhibits fusion by causing a local disturbance of the natural 6HB conformation.
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21
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Miyauchi K, Kozlov MM, Melikyan GB. Early steps of HIV-1 fusion define the sensitivity to inhibitory peptides that block 6-helix bundle formation. PLoS Pathog 2009; 5:e1000585. [PMID: 19763181 PMCID: PMC2736578 DOI: 10.1371/journal.ppat.1000585] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2009] [Accepted: 08/24/2009] [Indexed: 11/18/2022] Open
Abstract
The HIV envelope (Env) glycoprotein mediates membrane fusion through sequential interactions with CD4 and coreceptors, followed by the refolding of the transmembrane gp41 subunit into the stable 6-helix bundle (6HB) conformation. Synthetic peptides derived from the gp41 C-terminal heptad repeat domain (C-peptides) potently inhibit fusion by binding to the gp41 pre-bundle intermediates and blocking their conversion into the 6HB. Our recent work revealed that HIV-1 enters cells by fusing with endosomes, but not with the plasma membrane. These studies also showed that, for the large part, gp41 pre-bundles progress toward 6HBs in endosomal compartments and are thus protected from external fusion inhibitors. Here, we examined the consequences of endocytic entry on the gp41 pre-bundle exposure and on the virus' sensitivity to C-peptides. The rates of CD4 and coreceptor binding, as well as the rate of productive receptor-mediated endocytosis, were measured by adding specific inhibitors of these steps at varied times of virus-cell incubation. Following the CD4 binding, CCR5-tropic viruses recruited a requisite number of coreceptors much faster than CXCR4-tropic viruses. The rate of subsequent uptake of ternary Env-CD4-coreceptor complexes did not correlate with the kinetics of coreceptor engagement. These measurements combined with kinetic analyses enabled the determination of the lifetime of pre-bundle intermediates on the cell surface. Overall, these lifetimes correlated with the inhibitory potency of C-peptides. On the other hand, the basal sensitivity to peptides varied considerably among diverse HIV-1 isolates and ranked similarly with their susceptibility to inactivation by soluble CD4. We conclude that both the longevity of gp41 intermediates and the extent of irreversible conformational changes in Env upon CD4 binding determine the antiviral potency of C-peptides. The human immunodeficiency virus (HIV) envelope glycoprotein (Env) mediates fusion between the viral and cell membranes. The fusion is initiated by Env-receptor interactions and is followed by coreceptor binding and refolding of the transmembrane gp41 subunit. The gp41 refolding proceeds through several distinct intermediates, culminating in the formation of a final helical bundle structure which is blocked by inhibitory peptides targeting the complementary domains of gp41. We have recently shown that the exposure time of gp41 intermediates on the cell surface is limited by productive HIV endocytosis leading to fusion with endosomes. Here, we measured the rates of progression of different HIV isolates through distinct intermediate steps accessible to fusion inhibitors and correlated these rates with the inhibitory potency of peptides against these viruses. Whereas the potency of peptides was proportional to the lifetime of gp41 intermediates on the cell surface, the baseline sensitivity of the virus was also Env context-dependent. Higher concentrations of these inhibitors were required to block fusion induced by glycoproteins that were more resistant to inactivation by the soluble receptor. Collectively, these findings imply that both the kinetic factors and the stability of Env-receptor complexes control the HIV sensitivity to inhibitory peptides.
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Affiliation(s)
- Kosuke Miyauchi
- Institute of Human Virology and Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Michael M. Kozlov
- Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Gregory B. Melikyan
- Institute of Human Virology and Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
- * E-mail:
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22
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Gustchina E, Louis JM, Frisch C, Ylera F, Lechner A, Bewley CA, Clore GM. Affinity maturation by targeted diversification of the CDR-H2 loop of a monoclonal Fab derived from a synthetic naïve human antibody library and directed against the internal trimeric coiled-coil of gp41 yields a set of Fabs with improved HIV-1 neutralization potency and breadth. Virology 2009; 393:112-9. [PMID: 19695655 DOI: 10.1016/j.virol.2009.07.019] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2009] [Revised: 06/28/2009] [Accepted: 07/19/2009] [Indexed: 10/20/2022]
Abstract
Previously we reported a broadly HIV-1 neutralizing mini-antibody (Fab 3674) of modest potency that was derived from a human non-immune phage library by panning against the chimeric gp41-derived construct N(CCG)-gp41. This construct presents the N-heptad repeat of the gp41 ectodomain as a stable, helical, disulfide-linked trimer that extends in helical phase from the six-helix bundle of gp41. In this paper, Fab 3674 was subjected to affinity maturation against the N(CCG)-gp41 antigen by targeted diversification of the CDR-H2 loop to generate a panel of Fabs with diverse neutralization activity. Three affinity-matured Fabs selected for further study, Fabs 8060, 8066 and 8068, showed significant increases in both potency and breadth of neutralization against HIV-1 pseudotyped with envelopes of primary isolates from the standard subtype B and C HIV-1 reference panels. The parental Fab 3674 is 10-20-fold less potent in monovalent than bivalent format over the entire B and C panels of HIV-1 pseudotypes. Of note is that the improved neutralization activity of the affinity-matured Fabs relative to the parental Fab 3674 was, on average, significantly greater for the Fabs in monovalent than bivalent format. This suggests that the increased avidity of the Fabs for the target antigen in bivalent format can be partially offset by kinetic and/or steric advantages afforded by the smaller monovalent Fabs. Indeed, the best affinity-matured Fab (8066) in monovalent format ( approximately 50 kDa) was comparable in HIV-1 neutralization potency to the parental Fab 3674 in bivalent format ( approximately 120 kDa) across the subtype B and C reference panels.
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Affiliation(s)
- Elena Gustchina
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0520, USA
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Combinations of the first and next generations of human immunodeficiency virus (HIV) fusion inhibitors exhibit a highly potent synergistic effect against enfuvirtide- sensitive and -resistant HIV type 1 strains. J Virol 2009; 83:7862-72. [PMID: 19493996 DOI: 10.1128/jvi.00168-09] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
T20 (generic name, enfuvirtide; brand name, Fuzeon) is a first-generation human immunodeficiency virus (HIV) fusion inhibitor approved for salvage therapy of HIV-infected patients refractory to current antiretroviral drugs. However, its clinical use is limited because of rapid emergence of T20-resistant viruses in T20-treated patients. Therefore, T1249 and T1144 are being developed as the second- and third-generation HIV fusion inhibitors, respectively, with improved efficacy and drug resistance profiles. Here, we found that combinations of T20 with T1249 and/or T1144 resulted in exceptionally potent synergism (combination index, <0.01) against HIV-1-mediated membrane fusion by 2 to 3 orders of magnitude in dose reduction. Highly potent synergistic antiviral efficacy was also achieved against infection by laboratory-adapted and primary HIV-1 strains, including T20-resistant variants. The mechanism underlying the synergistic effect could be attributed to the fact that T20, T1249, and T1144 all contain different functional domains and have different primary binding sites in gp41. As such, they may work cooperatively to inhibit gp41 six-helix bundle core formation, thereby suppressing virus-cell fusion. Therefore, these findings strongly imply that, rather than replacing T20, combining it with HIV fusion inhibitors of different generations might produce synergistic activity against both T20-sensitive and -resistant HIV-1 strains, suggesting a new therapeutic strategy for the treatment of HIV-1 infection/AIDS.
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Utilization of immunoglobulin G Fc receptors by human immunodeficiency virus type 1: a specific role for antibodies against the membrane-proximal external region of gp41. J Virol 2009; 83:7397-410. [PMID: 19458010 DOI: 10.1128/jvi.00656-09] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Receptors (FcgammaRs) for the constant region of immunoglobulin G (IgG) are an important link between humoral immunity and cellular immunity. To help define the role of FcgammaRs in determining the fate of human immunodeficiency virus type 1 (HIV-1) immune complexes, cDNAs for the four major human Fcgamma receptors (FcgammaRI, FcgammaRIIa, FcgammaRIIb, and FcgammaRIIIa) were stably expressed by lentiviral transduction in a cell line (TZM-bl) commonly used for standardized assessments of HIV-1 neutralization. Individual cell lines, each expressing a different FcgammaR, bound human IgG, as evidence that the physical properties of the receptors were preserved. In assays with a HIV-1 multisubtype panel, the neutralizing activities of two monoclonal antibodies (2F5 and 4E10) that target the membrane-proximal external region (MPER) of gp41 were potentiated by FcgammaRI and, to a lesser extent, by FcgammaRIIb. Moreover, the neutralizing activity of an HIV-1-positive plasma sample known to contain gp41 MPER-specific antibodies was potentiated by FcgammaRI. The neutralizing activities of monoclonal antibodies b12 and 2G12 and other HIV-1-positive plasma samples were rarely affected by any of the four FcgammaRs. Effects with gp41 MPER-specific antibodies were moderately stronger for IgG1 than for IgG3 and were ineffective for Fab. We conclude that FcgammaRI and FcgammaRIIb facilitate antibody-mediated neutralization of HIV-1 by a mechanism that is dependent on the Fc region, IgG subclass, and epitope specificity of antibody. The FcgammaR effects seen here suggests that the MPER of gp41 could have greater value for vaccines than previously recognized.
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Examination of the contributions of size and avidity to the neutralization mechanisms of the anti-HIV antibodies b12 and 4E10. Proc Natl Acad Sci U S A 2009; 106:7385-90. [PMID: 19372381 DOI: 10.1073/pnas.0811427106] [Citation(s) in RCA: 125] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Monoclonal antibodies b12 and 4E10 are broadly neutralizing against a variety of strains of the human immunodeficiency virus type 1 (HIV-1). The epitope for b12 maps to the CD4-binding site in the gp120 subunit of HIV-1's trimeric gp120-gp41 envelope spike, whereas 4E10 recognizes the membrane-proximal external region (MPER) of gp41. Here, we constructed and compared a series of architectures for the b12 and 4E10 combining sites that differed in size, valency, and flexibility. In a comparative analysis of the ability of the b12 and 4E10 constructs to neutralize a panel of clade B HIV-1 strains, we observed that the ability of bivalent constructs to cross-link envelope spikes on the virion surface made a greater contribution to neutralization by b12 than by 4E10. Increased distance and flexibility between antibody combining sites correlated with enhanced neutralization for both antibodies, suggesting restricted mobility for the trimeric spikes embedded in the virion surface. The size of a construct did not appear to be correlated with neutralization potency for b12, but larger 4E10 constructs exhibited a steric occlusion effect, which we interpret as evidence for restricted access to its gp41 epitope. The combination of limited avidity and steric occlusion suggests a mechanism for evading neutralization by antibodies that target epitopes in the highly conserved MPER of gp41.
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Plaza A, Bifulco G, Keffer JL, Lloyd JR, Baker HL, Bewley CA. Celebesides A-C and theopapuamides B-D, depsipeptides from an Indonesian sponge that inhibit HIV-1 entry. J Org Chem 2009; 74:504-12. [PMID: 19072692 PMCID: PMC2656767 DOI: 10.1021/jo802232u] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Six new depsipeptides belonging to two different structural classes, termed celebesides A-C and theopapuamides B-D, have been isolated from the marine sponge Siliquariaspongia mirabilis. Their structures were determined using extensive 2D NMR and ESI-MS/MS techniques. Celebesides are unusual cyclic depsipeptides that comprise a polyketide moiety and five amino acid residues, including an uncommon 3-carbamoyl threonine, and a phosphoserine residue in celebesides A and B. Theopapuamides B-D are undecapeptides with an N-terminal fatty acid moiety containing two previously unreported amino acids, 3-acetamido-2-aminopropanoic acid and 4-amino-2,3-dihydroxy-5-methylhexanoic acid. The relative configuration of the polyketide moiety in celebesides was resolved by J-based analysis and quantum mechanical calculations, the results of which were self-consistent. Celebeside A neutralized HIV-1 in a single-round infectivity assay with an IC(50) value of 1.9 +/- 0.4 microg/mL while the nonphosphorylated analog celebeside C was inactive at concentrations as high as 50 microg/mL. Theopapuamides A-C showed cytotoxicity against human colon carcinoma (HCT-116) cells with IC(50) values between 2.1 and 4.0 microg/mL and exhibited strong antifungal activity against wildtype and amphotericin B-resistant strains of Candida albicans at loads of 1-5 microg/disk.
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Affiliation(s)
- Alberto Plaza
- Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-0820
| | - Giuseppe Bifulco
- Dipartimento di Scienze Farmaceutiche, University of Salerno, Via Ponte Don Melillo, 84084 Fisciano, Salerno, Italy
| | - Jessica L. Keffer
- Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-0820
| | - John R. Lloyd
- Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-0820
| | - Heather L. Baker
- Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-0820
| | - Carole A. Bewley
- Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-0820
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