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Sun L, Chen B, Liu X, Zhu Y, Zhang G, Liang X, Xing L, Xu W, Jiang S, Wang X. Alpaca-derived nanobody targeting the hydrophobic pocket of the HIV-1 gp41 NHR broadly neutralizes HIV-1 by blocking six-helix bundle formation. CURRENT RESEARCH IN MICROBIAL SCIENCES 2024; 7:100263. [PMID: 39176008 PMCID: PMC11339056 DOI: 10.1016/j.crmicr.2024.100263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/24/2024] Open
Abstract
The highly conserved hydrophobic pocket region of HIV-1 gp41 NHR triple-stranded coiled coil is crucial for the binding of CHR to NHR to form a six-helix bundle (6-HB). This pocket is only exposed instantaneously during fusion, making it an ideal target for antibody drug design. However, IgG molecule is too big to enter the pocket during the fusion process. Therefore, to overcome the steric hindrance and kinetic obstacles caused by the formation of gp41 pre-hairpin fusion intermediate, we obtained nanobodies (Nbs) targeting NHR by immunizing alpaca with an NHR-trimer mimic. Specifically, we identified a Nb, Nb-172, that exhibited potent and broadly neutralizing activity against HIV-1 pseudoviruses, HIV-1 primary isolates, and T20-resistant HIV-1 strains. In addition, the combinatorial use of mD1.22 and Nb-172 exhibited synergism in inhibiting HIV-1 infection inactivating cell-free virions. Nb-172 can competitively bind to the hydrophobic pocket of gp41 NHR to inhibit 6-HB formation. These findings suggest that Nb-172 merits further investigation as a potential therapeutic for HIV-1 infection.
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Affiliation(s)
- Lujia Sun
- Shanghai Institute of Infectious Disease and Biosecurity, Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences, Shanghai Frontiers Science Center of Pathogenic Microbes and Infection, Fudan University, Shanghai, China
| | - Bo Chen
- Chengdu NBbiolab. CO., LTD, SME Incubation Park, 319 Qingpi Avenue, Chengdu, China
| | - Xianbo Liu
- Chengdu NBbiolab. CO., LTD, SME Incubation Park, 319 Qingpi Avenue, Chengdu, China
| | - Yun Zhu
- National Key Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Guangxu Zhang
- Shanghai Institute of Infectious Disease and Biosecurity, Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences, Shanghai Frontiers Science Center of Pathogenic Microbes and Infection, Fudan University, Shanghai, China
| | - Xiaoxing Liang
- Shanghai Institute of Infectious Disease and Biosecurity, Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences, Shanghai Frontiers Science Center of Pathogenic Microbes and Infection, Fudan University, Shanghai, China
| | - Lixiao Xing
- Shanghai Institute of Infectious Disease and Biosecurity, Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences, Shanghai Frontiers Science Center of Pathogenic Microbes and Infection, Fudan University, Shanghai, China
| | - Wei Xu
- Shanghai Institute of Infectious Disease and Biosecurity, Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences, Shanghai Frontiers Science Center of Pathogenic Microbes and Infection, Fudan University, Shanghai, China
| | - Shibo Jiang
- Shanghai Institute of Infectious Disease and Biosecurity, Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences, Shanghai Frontiers Science Center of Pathogenic Microbes and Infection, Fudan University, Shanghai, China
| | - Xinling Wang
- Shanghai Institute of Infectious Disease and Biosecurity, Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences, Shanghai Frontiers Science Center of Pathogenic Microbes and Infection, Fudan University, Shanghai, China
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2
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Zhang Z, Anang S, Nguyen HT, Fritschi C, Smith AB, Sodroski JG. Membrane HIV-1 envelope glycoproteins stabilized more strongly in a pretriggered conformation than natural virus Envs. iScience 2024; 27:110141. [PMID: 38979012 PMCID: PMC11228805 DOI: 10.1016/j.isci.2024.110141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Revised: 04/08/2024] [Accepted: 05/27/2024] [Indexed: 07/10/2024] Open
Abstract
The pretriggered conformation of the human immunodeficiency virus (HIV-1) envelope glycoprotein (Env) trimer ((gp120/gp41)3) is targeted by virus entry inhibitors and broadly neutralizing antibodies (bNAbs). The lability of pretriggered Env has hindered its characterization. Here, we produce membrane Env variants progressively stabilized in pretriggered conformations, in some cases to a degree beyond that found in natural HIV-1 strains. Pretriggered Env stability correlated with stronger trimer subunit association, increased virus sensitivity to bNAb neutralization, and decreased capacity to mediate cell-cell fusion and virus entry. For some highly stabilized Env mutants, after virus-host cell engagement, the normally inaccessible gp120 V3 region on an Env intermediate became targetable by otherwise poorly neutralizing antibodies. Thus, evolutionary pressure on HIV-1 Env to maintain trimer integrity, responsiveness to the CD4 receptor, and resistance to antibodies modulates pretriggered Env stability. The strongly stabilized pretriggered membrane Envs reported here will facilitate further characterization of this functionally important conformation.
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Affiliation(s)
- Zhiqing Zhang
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, MA 02215, USA
- Department of Microbiology, Harvard Medical School, Boston, MA 02115, USA
| | - Saumya Anang
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, MA 02215, USA
- Department of Microbiology, Harvard Medical School, Boston, MA 02115, USA
| | - Hanh T Nguyen
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, MA 02215, USA
- Department of Microbiology, Harvard Medical School, Boston, MA 02115, USA
| | - Christopher Fritschi
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Amos B Smith
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Joseph G Sodroski
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, MA 02215, USA
- Department of Microbiology, Harvard Medical School, Boston, MA 02115, USA
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3
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Webb NE, Sevareid CM, Sanchez C, Tobin NH, Aldrovandi GM. Natural Variation in HIV-1 Entry Kinetics Map to Specific Residues and Reveal an Interdependence Between Attachment and Fusion. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.25.600587. [PMID: 38979136 PMCID: PMC11230229 DOI: 10.1101/2024.06.25.600587] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/10/2024]
Abstract
HIV-1 entry kinetics reflect the fluid motion of the HIV envelope glycoprotein through at least three major structural configurations that drive virus-cell membrane fusion. The lifetime of each state is an important component of potency for inhibitors that target them. We used the time-of-addition inhibitor assay and a novel analytical strategy to define the kinetics of pre-hairpin exposure (using T20) and co-receptor engagement (via. maraviroc), through a characteristic delay metric, across a variety of naturally occurring HIV Env isolates. Among 257 distinct HIV-1 envelope isolates we found a remarkable breadth of T20 and maraviroc delays ranging from as early as 30 seconds to as late as 60 minutes. The most extreme delays were observed among transmission-linked clade C isolates. We identified four single-residue determinants of late T20 and maraviroc delays that are associated with either receptor engagement or gp41 function. Comparison of these delays with T20 sensitivity suggest co-receptor engagement and fusogenic activity in gp41 act cooperatively but sequentially to drive entry. Our findings support current models of entry where co-receptor engagement drives gp41 eclipse and have strong implications for the design of entry inhibitors and antibodies that target transient entry states. Author Summary The first step of HIV-1 infection is entry, where virus-cell membrane fusion is driven by the HIV-1 envelope glycoprotein through a series of conformational changes. Some of the most broadly active entry inhibitors work by binding conformations that exist only transiently during entry. The lifetimes of these states and the kinetics of entry are important elements of inhibitor activity for which little is known. We demonstrate a remarkable range of kinetics among 257 diverse HIV-1 isolates and find that this phenotype is highly flexible, with multiple single-residue determinants. Examination of the kinetics of two conformational landmarks shed light on novel kinetic features that offer new details about the role of co-receptor engagement and provide a framework to explain entry inhibitor synergy.
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4
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Wang Q, Zhang S, Nguyen HT, Sodroski J. Inhibition of human immunodeficiency virus (HIV-1) infectivity by expression of poorly or broadly neutralizing antibodies against Env in virus-producing cells. J Virol 2024; 98:e0159423. [PMID: 38289101 PMCID: PMC10878270 DOI: 10.1128/jvi.01594-23] [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: 11/30/2023] [Accepted: 12/19/2023] [Indexed: 02/21/2024] Open
Abstract
The human immunodeficiency virus (HIV-1) envelope (Env) glycoprotein precursor (gp160) trimerizes, is modified by high-mannose glycans in the endoplasmic reticulum, and is transported via Golgi and non-Golgi secretory pathways to the infected cell surface. In the Golgi, gp160 is partially modified by complex carbohydrates and proteolytically cleaved to produce the mature functional Env trimer, which is preferentially incorporated into virions. Broadly neutralizing antibodies (bNAbs) generally recognize the cleaved Env trimer, whereas poorly neutralizing antibodies (pNAbs) bind the conformationally flexible gp160. We found that expression of bNAbs, pNAbs, or soluble/membrane forms of the receptor, CD4, in cells producing HIV-1 all decreased viral infectivity. Four patterns of co-expressed ligand:Env were observed: (i) ligands (CD4, soluble CD4-Ig, and some pNAbs) that specifically recognize the CD4-bound Env conformation resulted in uncleaved Envs lacking complex glycans that were not incorporated into virions; (ii) other pNAbs produced Envs with some complex carbohydrates and severe defects in cleavage, which were relieved by brefeldin A treatment; (iii) bNAbs that recognize gp160 as well as mature Envs resulted in Envs with some complex carbohydrates and moderate decreases in virion Env cleavage; and (iv) bNAbs that preferentially recognize mature Envs produced cleaved Envs with complex glycans in cells and on virions. The low infectivity observed upon co-expression of pNAbs or CD4 could be explained by disruption of Env trafficking, reducing the level of Env and/or increasing the fraction of uncleaved Env on virions. In addition to bNAb effects on virion Env cleavage, the secreted bNAbs neutralized the co-expressed viruses.IMPORTANCEThe Env trimers on the HIV-1 mediate virus entry into host cells. Env is synthesized in infected cells, modified by complex sugars, and cleaved to form a mature, functional Env, which is incorporated into virus particles. Env elicits antibodies in infected individuals, some of which can neutralize the virus. We found that antibodies co-expressed in the virus-producing cell can disrupt Env transit to the proper compartment for cleavage and sugar modification and, in some cases, block incorporation into viruses. These studies provide insights into the processes by which Env becomes functional in the virus-producing cell and may assist attempts to interfere with these events to inhibit HIV-1 infection.
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Affiliation(s)
- Qian Wang
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Shijian Zhang
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Hanh T. Nguyen
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, 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
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5
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Anang S, Zhang S, Fritschi C, Chiu TJ, Yang D, Smith III AB, Madani N, Sodroski J. V3 tip determinants of susceptibility to inhibition by CD4-mimetic compounds in natural clade A human immunodeficiency virus (HIV-1) envelope glycoproteins. J Virol 2023; 97:e0117123. [PMID: 37888980 PMCID: PMC10688366 DOI: 10.1128/jvi.01171-23] [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: 07/28/2023] [Accepted: 10/12/2023] [Indexed: 10/28/2023] Open
Abstract
IMPORTANCE CD4-mimetic compounds (CD4mcs) are small-molecule inhibitors of human immunodeficiency virus (HIV-1) entry into host cells. CD4mcs target a pocket on the viral envelope glycoprotein (Env) spike that is used for binding to the receptor, CD4, and is highly conserved among HIV-1 strains. Nonetheless, naturally occurring HIV-1 strains exhibit a wide range of sensitivities to CD4mcs. Our study identifies changes distant from the binding pocket that can influence the susceptibility of natural HIV-1 strains to the antiviral effects of multiple CD4mcs. We relate the antiviral potency of the CD4mc against this panel of HIV-1 variants to the ability of the CD4mc to activate entry-related changes in Env conformation prematurely. These findings will guide efforts to improve the potency and breadth of CD4mcs against natural HIV-1 variants.
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Affiliation(s)
- Saumya Anang
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Shijian Zhang
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Christopher Fritschi
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Ta-Jung Chiu
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Derek Yang
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Amos B. Smith III
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Navid Madani
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, 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
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6
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Li W, Qin Z, Nand E, Grunst MW, Grover JR, Bess JW, Lifson JD, Zwick MB, Tagare HD, Uchil PD, Mothes W. HIV-1 Env trimers asymmetrically engage CD4 receptors in membranes. Nature 2023; 623:1026-1033. [PMID: 37993716 PMCID: PMC10686830 DOI: 10.1038/s41586-023-06762-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2022] [Accepted: 10/19/2023] [Indexed: 11/24/2023]
Abstract
Human immunodeficiency virus 1 (HIV-1) infection is initiated by binding of the viral envelope glycoprotein (Env) to the cell-surface receptor CD41-4. Although high-resolution structures of Env in a complex with the soluble domains of CD4 have been determined, the binding process is less understood in native membranes5-13. Here we used cryo-electron tomography to monitor Env-CD4 interactions at the membrane-membrane interfaces formed between HIV-1 and CD4-presenting virus-like particles. Env-CD4 complexes organized into clusters and rings, bringing the opposing membranes closer together. Env-CD4 clustering was dependent on capsid maturation. Subtomogram averaging and classification revealed that Env bound to one, two and finally three CD4 molecules, after which Env adopted an open state. Our data indicate that asymmetric HIV-1 Env trimers bound to one and two CD4 molecules are detectable intermediates during virus binding to host cell membranes, which probably has consequences for antibody-mediated immune responses and vaccine immunogen design.
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Affiliation(s)
- Wenwei Li
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, CT, USA.
| | - Zhuan Qin
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, CT, USA
| | - Elizabeth Nand
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, CT, USA
| | - Michael W Grunst
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, CT, USA
| | - Jonathan R Grover
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, CT, USA
| | - Julian W Bess
- AIDS and Cancer Virus Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Jeffrey D Lifson
- AIDS and Cancer Virus Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Michael B Zwick
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA, USA
| | - Hemant D Tagare
- Department of Radiology and Biomedical Imaging, Yale University, New Haven, CT, USA
| | - Pradeep D Uchil
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, CT, USA
| | - Walther Mothes
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, CT, USA.
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7
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Dam KMA, Fan C, Yang Z, Bjorkman PJ. Intermediate conformations of CD4-bound HIV-1 Env heterotrimers. Nature 2023; 623:1017-1025. [PMID: 37993719 PMCID: PMC10686819 DOI: 10.1038/s41586-023-06639-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Accepted: 09/13/2023] [Indexed: 11/24/2023]
Abstract
HIV-1 envelope (Env) exhibits distinct conformational changes in response to host receptor (CD4) engagement. Env, a trimer of gp120 and gp41 heterodimers, has been structurally characterized in a closed, prefusion conformation with closely associated gp120s and coreceptor binding sites on gp120 V3 hidden by V1V2 loops1-4 and in fully saturated CD4-bound open Env conformations with changes including outwardly rotated gp120s and displaced V1V2 loops3-9. To investigate changes resulting from substoichiometric CD4 binding, we solved single-particle cryo-electron microscopy (cryo-EM) structures of soluble, native-like heterotrimeric Envs bound to one or two CD4 molecules. Most of the Env trimers bound to one CD4 adopted the closed, prefusion Env state, with a minority exhibiting a heterogeneous partially open Env conformation. When bound to two CD4s, the CD4-bound gp120s exhibited an open Env conformation including a four-stranded gp120 bridging sheet and displaced gp120 V1V2 loops that expose the coreceptor sites on V3. The third gp120 adopted an intermediate, occluded-open state10 that showed gp120 outward rotation but maintained the prefusion three-stranded gp120 bridging sheet with only partial V1V2 displacement and V3 exposure. We conclude that most of the engagements with one CD4 molecule were insufficient to stimulate CD4-induced conformational changes, whereas binding two CD4 molecules led to Env opening in CD4-bound protomers only. The substoichiometric CD4-bound soluble Env heterotrimer structures resembled counterparts derived from a cryo-electron tomography study of complexes between virion-bound Envs and membrane-anchored CD4 (ref. 11), validating their physiological relevance. Together, these results illuminate intermediate conformations of HIV-1 Env and illustrate its structural plasticity.
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Affiliation(s)
- Kim-Marie A Dam
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Chengcheng Fan
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Zhi Yang
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
| | - Pamela J Bjorkman
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA.
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8
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Nguyen HT, Wang Q, Anang S, Sodroski JG. Characterization of the Human Immunodeficiency Virus (HIV-1) Envelope Glycoprotein Conformational States on Infectious Virus Particles. J Virol 2023; 97:e0185722. [PMID: 36815832 PMCID: PMC10062176 DOI: 10.1128/jvi.01857-22] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Accepted: 02/01/2023] [Indexed: 02/24/2023] Open
Abstract
Human immunodeficiency virus (HIV-1) entry into cells involves triggering of the viral envelope glycoprotein (Env) trimer ([gp120/gp41]3) by the primary receptor, CD4, and coreceptors, CCR5 or CXCR4. The pretriggered (State-1) conformation of the mature (cleaved) Env is targeted by broadly neutralizing antibodies (bNAbs), which are inefficiently elicited compared with poorly neutralizing antibodies (pNAbs). Here, we characterize variants of the moderately triggerable HIV-1AD8 Env on virions produced by an infectious molecular proviral clone; such virions contain more cleaved Env than pseudotyped viruses. We identified three types of cleaved wild-type AD8 Env trimers on virions: (i) State-1-like trimers preferentially recognized by bNAbs and exhibiting strong subunit association; (ii) trimers recognized by pNAbs directed against the gp120 coreceptor-binding region and exhibiting weak, detergent-sensitive subunit association; and (iii) a minor gp41-only population. The first Env population was enriched and the other Env populations reduced by introducing State-1-stabilizing changes in the AD8 Env or by treatment of the virions with crosslinker or the State-1-preferring entry inhibitor, BMS-806. These stabilized AD8 Envs were also more resistant to gp120 shedding induced by a CD4-mimetic compound or by incubation on ice. Conversely, a State-1-destabilized, CD4-independent AD8 Env variant exhibited weaker bNAb recognition and stronger pNAb recognition. Similar relationships between Env triggerability and antigenicity/shedding propensity on virions were observed for other HIV-1 strains. State-1 Envs on virions can be significantly enriched by minimizing the adventitious incorporation of uncleaved Env; stabilizing the pretriggered conformation by Env modification, crosslinking or BMS-806 treatment; strengthening Env subunit interactions; and using CD4-negative producer cells. IMPORTANCE Efforts to develop an effective HIV-1 vaccine have been frustrated by the inability to elicit broad neutralizing antibodies that recognize multiple virus strains. Such antibodies can bind a particular shape of the HIV-1 envelope glycoprotein trimer, as it exists on a viral membrane but before engaging receptors on the host cell. Here, we establish simple yet powerful assays to characterize the envelope glycoproteins in a natural context on virus particles. We find that, depending on the HIV-1 strain, some envelope glycoproteins change shape and fall apart, creating decoys that can potentially divert the host immune response. We identify requirements to keep the relevant envelope glycoprotein target for broad neutralizing antibodies intact on virus-like particles. These studies suggest strategies that should facilitate efforts to produce and use virus-like particles as vaccine immunogens.
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Affiliation(s)
- Hanh T. Nguyen
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Qian Wang
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Saumya Anang
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Joseph G. Sodroski
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
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9
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Fritschi CJ, Anang S, Gong Z, Mohammadi M, Richard J, Bourassa C, Severino KT, Richter H, Yang D, Chen HC, Chiu TJ, Seaman MS, Madani N, Abrams C, Finzi A, Hendrickson WA, Sodroski JG, Smith AB. Indoline CD4-mimetic compounds mediate potent and broad HIV-1 inhibition and sensitization to antibody-dependent cellular cytotoxicity. Proc Natl Acad Sci U S A 2023; 120:e2222073120. [PMID: 36961924 PMCID: PMC10068826 DOI: 10.1073/pnas.2222073120] [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: 12/31/2022] [Accepted: 02/22/2023] [Indexed: 03/26/2023] Open
Abstract
Binding to the host cell receptors, CD4 and CCR5/CXCR4, triggers large-scale conformational changes in the HIV-1 envelope glycoprotein (Env) trimer [(gp120/gp41)3] that promote virus entry into the cell. CD4-mimetic compounds (CD4mcs) comprise small organic molecules that bind in the highly conserved CD4-binding site of gp120 and prematurely induce inactivating Env conformational changes, including shedding of gp120 from the Env trimer. By inducing more "open," antibody-susceptible Env conformations, CD4mcs also sensitize HIV-1 virions to neutralization by antibodies and infected cells to antibody-dependent cellular cytotoxicity (ADCC). Here, we report the design, synthesis, and evaluation of novel CD4mcs based on an indoline scaffold. Compared with our current lead indane scaffold CD4mc, BNM-III-170, several indoline CD4mcs exhibit increased potency and breadth against HIV-1 variants from different geographic clades. Viruses that were selected for resistance to the lead indane CD4mc, BNM-III-170, are susceptible to inhibition by the indoline CD4mcs. The indoline CD4mcs also potently sensitize HIV-1-infected cells to ADCC mediated by plasma from HIV-1-infected individuals. Crystal structures indicate that the indoline CD4mcs gain potency compared to the indane CD4mcs through more favorable π-π overlap from the indoline pose and by making favorable contacts with the vestibule of the CD4-binding pocket on gp120. The rational design of indoline CD4mcs thus holds promise for further improvements in antiviral activity, potentially contributing to efforts to treat and prevent HIV-1 infection.
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Affiliation(s)
| | - Saumya Anang
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA02115
- Department of Microbiology, Harvard Medical School, Boston, MA02115
| | - Zhen Gong
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY10032
| | | | - Jonathan Richard
- Centre de Recherche du CHUM, Montreal, QCH2X 0A9, Canada
- Departement de Microbiologie, Infectiologie et Immunologie, Universite de Montreal, Montreal, QCH3T 1J4, Canada
| | - Catherine Bourassa
- Departement de Microbiologie, Infectiologie et Immunologie, Universite de Montreal, Montreal, QCH3T 1J4, Canada
| | - Kenny T. Severino
- Center for Virology and Vaccine Research, Beth Israel Deaconess Medical Center, Boston, MA02215
| | - Hannah Richter
- Center for Virology and Vaccine Research, Beth Israel Deaconess Medical Center, Boston, MA02215
| | - Derek Yang
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA19104
| | - Hung-Ching Chen
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA19104
| | - Ta-Jung Chiu
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA19104
| | - Michael S. Seaman
- Center for Virology and Vaccine Research, Beth Israel Deaconess Medical Center, Boston, MA02215
| | - Navid Madani
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA02115
- Department of Microbiology, Harvard Medical School, Boston, MA02115
| | - Cameron Abrams
- Department of Chemical and Biological Engineering, Drexel University, Philadelphia, PA19104
| | - Andrés Finzi
- Centre de Recherche du CHUM, Montreal, QCH2X 0A9, Canada
- Departement de Microbiologie, Infectiologie et Immunologie, Universite de Montreal, Montreal, QCH3T 1J4, Canada
| | - Wayne A. Hendrickson
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY10032
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY10032
| | - Joseph G. Sodroski
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA02115
- Department of Microbiology, Harvard Medical School, Boston, MA02115
- Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, MA02115
| | - Amos B. Smith
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA19104
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10
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Tada T, Dcosta BM, Zhou H, Landau NR. Prophylaxis and treatment of SARS-CoV-2 infection by an ACE2 receptor decoy in a preclinical animal model. iScience 2023; 26:106092. [PMID: 36741912 PMCID: PMC9886562 DOI: 10.1016/j.isci.2023.106092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 12/09/2022] [Accepted: 01/26/2023] [Indexed: 02/01/2023] Open
Abstract
The emergence of SARS-CoV-2 variants with highly mutated spike proteins has presented an obstacle to the use of monoclonal antibodies for the prevention and treatment of SARS-CoV-2 infection. We show that a high-affinity receptor decoy protein in which a modified ACE2 ectodomain is fused to a single domain of an immunoglobulin heavy chain Fc region dramatically suppressed virus loads in mice upon challenge with a high dose of parental SARS-CoV-2 or Omicron variants. The decoy also potently suppressed virus replication when administered shortly post-infection. The decoy approach offers protection against the current viral variants and, potentially, against SARS-CoV-2 variants that may emerge with the continued evolution of the spike protein or novel viruses that use ACE2 for virus entry.
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Affiliation(s)
- Takuya Tada
- Department of Microbiology, NYU Grossman School of Medicine, 430 East 29th Street, Alexandria West Building, Rm 509, New York, NY 10016, USA
| | - Belinda M. Dcosta
- Department of Microbiology, NYU Grossman School of Medicine, 430 East 29th Street, Alexandria West Building, Rm 509, New York, NY 10016, USA
| | - Hao Zhou
- Department of Microbiology, NYU Grossman School of Medicine, 430 East 29th Street, Alexandria West Building, Rm 509, New York, NY 10016, USA
| | - Nathaniel R. Landau
- Department of Microbiology, NYU Grossman School of Medicine, 430 East 29th Street, Alexandria West Building, Rm 509, New York, NY 10016, USA
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11
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Matsumoto K, Kuwata T, Tolbert WD, Richard J, Ding S, Prévost J, Takahama S, Judicate GP, Ueno T, Nakata H, Kobayakawa T, Tsuji K, Tamamura H, Smith AB, Pazgier M, Finzi A, Matsushita S. Characterization of a Novel CD4 Mimetic Compound YIR-821 against HIV-1 Clinical Isolates. J Virol 2023; 97:e0163822. [PMID: 36511698 PMCID: PMC9888228 DOI: 10.1128/jvi.01638-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Accepted: 11/15/2022] [Indexed: 12/15/2022] Open
Abstract
Small CD4-mimetic compound (CD4mc), which inhibits the interaction between gp120 with CD4, acts as an entry inhibitor and induces structural changes in the HIV-1 envelope glycoprotein trimer (Env) through its insertion within the Phe43 cavity of gp120. We recently developed YIR-821, a novel CD4mc, that has potent antiviral activity and lower toxicity than the prototype NBD-556. To assess the possibility of clinical application of YIR-821, we tested its antiviral activity using a panel of HIV-1 pseudoviruses from different subtypes. YIR-821 displayed entry inhibitor activity against 53.5% (21/40) of the pseudoviruses tested and enhanced neutralization mediated by coreceptor binding site (CoRBS) antibodies in 50% (16/32) of these. Furthermore, when we assessed the antiviral effects using a panel of pseudoviruses and autologous plasma IgG, enhancement of antibody-mediated neutralization activity was observed for 48% (15/31) of subtype B strains and 51% (28/55) of non-B strains. The direct antiviral activity of YIR-821 as an entry inhibitor was observed in 53% of both subtype B (27/51) and non-B subtype (40/75) pseudoviruses. Enhancement of antibody-dependent cellular cytotoxicity was also observed with YIR-821 for all six selected clinical isolates, as well as for the transmitted/founder (T/F) CH58 virus-infected cells. The sequence diversity in the CD4 binding site as well as other regions, such as the gp120 inner domain layers or gp41, may be involved in the multiple mechanisms related to the sensitive/resistant phenotype of the virus to YIR-821. Our findings may facilitate the clinical application of YIR-821. IMPORTANCE Small CD4-mimetic compound (CD4mc) interacts with the Phe43 cavity and triggers conformational changes, enhancing antibody-mediated neutralization and antibody-dependent cellular cytotoxicity (ADCC). Here, we evaluated the effect of YIR-821, a novel CD4mc, against clinical isolates, including both subtype B and non-B subtype viruses. Our results confirm the desirable properties of YIR-821, which include entry inhibition, enhancement of IgG-neutralization, binding, and ADCC, in addition to low toxicity and long half-life in a rhesus macaque model, that might facilitate the clinical application of this novel CD4mc. Our observation of primary viruses that are resistant to YIR-821 suggests that further development of CD4mcs with different structural properties is required.
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Affiliation(s)
- Kaho Matsumoto
- Joint Research Center for Human Retrovirus Infection, Kumamoto University, Kumamoto, Japan
- Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan
| | - Takeo Kuwata
- Joint Research Center for Human Retrovirus Infection, Kumamoto University, Kumamoto, Japan
| | - William D. Tolbert
- Infectious Disease Division, Department of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Jonathan Richard
- Centre de Recherche du CHUM (CRCHUM), Montreal, Quebec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Faculté de Médecine, Université de Montréal, Montreal, Quebec, Canada
| | - Shilei Ding
- Centre de Recherche du CHUM (CRCHUM), Montreal, Quebec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Faculté de Médecine, Université de Montréal, Montreal, Quebec, Canada
| | - Jérémie Prévost
- Centre de Recherche du CHUM (CRCHUM), Montreal, Quebec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Faculté de Médecine, Université de Montréal, Montreal, Quebec, Canada
| | - Shokichi Takahama
- Laboratory of Immunosenescence, Center for Vaccine and Adjuvant Research, National Institutes of Biomedical Innovation, Health and Nutrition, Osaka, Japan
| | - George P. Judicate
- Joint Research Center for Human Retrovirus Infection, Kumamoto University, Kumamoto, Japan
| | - Takamasa Ueno
- Joint Research Center for Human Retrovirus Infection, Kumamoto University, Kumamoto, Japan
| | - Hirotomo Nakata
- Department of Hematology, Rheumatology, and Infectious Diseases, Graduate School of Medical Sciences, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Takuya Kobayakawa
- Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, Tokyo, Japan
| | - Kohei Tsuji
- Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, Tokyo, Japan
| | - Hirokazu Tamamura
- Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, Tokyo, Japan
| | - Amos B. Smith
- Department of Chemistry, School of Arts and Sciences, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Marzena Pazgier
- Infectious Disease Division, Department of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Andrés Finzi
- Centre de Recherche du CHUM (CRCHUM), Montreal, Quebec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Faculté de Médecine, Université de Montréal, Montreal, Quebec, Canada
| | - Shuzo Matsushita
- Joint Research Center for Human Retrovirus Infection, Kumamoto University, Kumamoto, Japan
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12
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Dam KMA, Fan C, Yang Z, Bjorkman PJ. Structural characterization of HIV-1 Env heterotrimers bound to one or two CD4 receptors reveals intermediate Env conformations. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.27.525985. [PMID: 36747804 PMCID: PMC9900888 DOI: 10.1101/2023.01.27.525985] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
HIV-1 envelope (Env) exhibits distinct conformational changes in response to host receptor (CD4) engagement. Env, a trimer of gp120/gp41 heterodimers, has been structurally characterized in a closed, prefusion conformation with closely associated gp120s and coreceptor binding sites on gp120 V3 hidden by V1V2 loops, and in fully-saturated CD4-bound open Env conformations with changes including outwardly rotated gp120s and displaced V1V2 loops. To investigate changes resulting from sub-stoichiometric CD4 binding, we solved 3.4Å and 3.9Å single-particle cryo-EM structures of soluble, native-like Envs bound to one or two CD4 molecules. Env trimer bound to one CD4 adopted the closed, prefusion Env state. When bound to two CD4s, the CD4-bound gp120s exhibited an open Env conformation including a four-stranded gp120 bridging sheet and displaced gp120 V1V2 loops that expose the coreceptor sites on V3. The third gp120 adopted an intermediate, occluded-open state that included gp120 outward rotation but maintained the prefusion, three-stranded gp120 bridging sheet and showed only partial V1V2 displacement and V3 exposure. We conclude that engagement of one CD4 molecule was insufficient to stimulate CD4-induced conformational changes, while binding two CD4 molecules led to Env opening in CD4-bound protomers only. Together, these results illuminate HIV-1 Env intermediate conformations and illustrate the structural plasticity of HIV-1 Env.
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Affiliation(s)
- Kim-Marie A Dam
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Chengcheng Fan
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Zhi Yang
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
- Present address: Department of Molecular and Cell Biology, University of California, 13 Berkeley, CA 94720, USA
| | - Pamela J Bjorkman
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
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13
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Prophylaxis and Treatment of SARS-CoV-2 infection by an ACE2 Receptor Decoy. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2022.12.31.522401. [PMID: 36656772 PMCID: PMC9844012 DOI: 10.1101/2022.12.31.522401] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The emergence of SARS-CoV-2 variants with highly mutated spike proteins has presented an obstacle to the use of monoclonal antibodies for the prevention and treatment of SARS-CoV-2 infection. We show that a high affinity receptor decoy protein in which a modified ACE2 ectodomain is fused to a single domain of an immunoglobulin heavy chain Fc region dramatically suppressed virus loads in mice upon challenge with a high dose of parental SARS-CoV-2 or Omicron variants. The decoy also potently suppressed virus replication when administered shortly post-infection. The decoy approach offers protection against the current viral variants and, potentially, against SARS-CoV-2 variants that may emerge with the continued evolution of the spike protein or novel viruses that use ACE2 for virus entry.
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14
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Anang S, Richard J, Bourassa C, Goyette G, Chiu TJ, Chen HC, Smith AB, Madani N, Finzi A, Sodroski J. Characterization of Human Immunodeficiency Virus (HIV-1) Envelope Glycoprotein Variants Selected for Resistance to a CD4-Mimetic Compound. J Virol 2022; 96:e0063622. [PMID: 35980207 PMCID: PMC9472635 DOI: 10.1128/jvi.00636-22] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Accepted: 07/30/2022] [Indexed: 11/20/2022] Open
Abstract
Binding to the host cell receptors CD4 and CCR5/CXCR4 triggers conformational changes in the human immunodeficiency virus (HIV-1) envelope glycoprotein (Env) trimer that promote virus entry. CD4 binding allows the gp120 exterior Env to bind CCR5/CXCR4 and induces a short-lived prehairpin intermediate conformation in the gp41 transmembrane Env. Small-molecule CD4-mimetic compounds (CD4mcs) bind within the conserved Phe-43 cavity of gp120, near the binding site for CD4. CD4mcs like BNM-III-170 inhibit HIV-1 infection by competing with CD4 and by prematurely activating Env, leading to irreversible inactivation. In cell culture, we selected and analyzed variants of the primary HIV-1AD8 strain resistant to BNM-III-170. Two changes (S375N and I424T) in gp120 residues that flank the Phe-43 cavity each conferred an ~5-fold resistance to BNM-III-170 with minimal fitness cost. A third change (E64G) in layer 1 of the gp120 inner domain resulted in ~100-fold resistance to BNM-III-170, ~2- to 3-fold resistance to soluble CD4-Ig, and a moderate decrease in viral fitness. The gp120 changes additively or synergistically contributed to BNM-III-170 resistance. The sensitivity of the Env variants to BNM-III-170 inhibition of virus entry correlated with their sensitivity to BNM-III-170-induced Env activation and shedding of gp120. Together, the S375N and I424T changes, but not the E64G change, conferred >100-fold and 33-fold resistance to BMS-806 and BMS-529 (temsavir), respectively, potent HIV-1 entry inhibitors that block Env conformational transitions. These studies identify pathways whereby HIV-1 can develop resistance to CD4mcs and conformational blockers, two classes of entry inhibitors that target the conserved gp120 Phe-43 cavity. IMPORTANCE CD4-mimetic compounds (CD4mcs) and conformational blockers like BMS-806 and BMS-529 (temsavir) are small-molecule inhibitors of human immunodeficiency virus (HIV-1) entry into host cells. Although CD4mcs and conformational blockers inhibit HIV-1 entry by different mechanisms, they both target a pocket on the viral envelope glycoprotein (Env) spike that is used for binding to the receptor CD4 and is highly conserved among HIV-1 strains. Our study identifies changes near this pocket that can confer various levels of resistance to the antiviral effects of a CD4mc and conformational blockers. We relate the antiviral potency of a CD4mc against this panel of HIV-1 variants to the ability of the CD4mc to activate changes in Env conformation and to induce the shedding of the gp120 exterior Env from the spike. These findings will guide efforts to improve the potency and breadth of small-molecule HIV-1 entry inhibitors.
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Affiliation(s)
- Saumya Anang
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Jonathan Richard
- Centre de Recherche du CHUM, Montreal, Quebec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, Quebec, Canada
| | - Catherine Bourassa
- Centre de Recherche du CHUM, Montreal, Quebec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, Quebec, Canada
| | - Guillaume Goyette
- Centre de Recherche du CHUM, Montreal, Quebec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, Quebec, Canada
| | - Ta-Jung Chiu
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Hung-Ching Chen
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Amos B. Smith
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Navid Madani
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Andrés Finzi
- Centre de Recherche du CHUM, Montreal, Quebec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, Quebec, Canada
| | - Joseph Sodroski
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
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15
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Stejskal L, Kalemera MD, Lewis CB, Palor M, Walker L, Daviter T, Lees WD, Moss DS, Kremyda-Vlachou M, Kozlakidis Z, Gallo G, Bailey D, Rosenberg W, Illingworth CJR, Shepherd AJ, Grove J. An entropic safety catch controls hepatitis C virus entry and antibody resistance. eLife 2022; 11:e71854. [PMID: 35796426 PMCID: PMC9333995 DOI: 10.7554/elife.71854] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Accepted: 06/28/2022] [Indexed: 11/24/2022] Open
Abstract
E1 and E2 (E1E2), the fusion proteins of Hepatitis C Virus (HCV), are unlike that of any other virus yet described, and the detailed molecular mechanisms of HCV entry/fusion remain unknown. Hypervariable region-1 (HVR-1) of E2 is a putative intrinsically disordered protein tail. Here, we demonstrate that HVR-1 has an autoinhibitory function that suppresses the activity of E1E2 on free virions; this is dependent on its conformational entropy. Thus, HVR-1 is akin to a safety catch that prevents premature triggering of E1E2 activity. Crucially, this mechanism is turned off by host receptor interactions at the cell surface to allow entry. Mutations that reduce conformational entropy in HVR-1, or genetic deletion of HVR-1, turn off the safety catch to generate hyper-reactive HCV that exhibits enhanced virus entry but is thermally unstable and acutely sensitive to neutralising antibodies. Therefore, the HVR-1 safety catch controls the efficiency of virus entry and maintains resistance to neutralising antibodies. This discovery provides an explanation for the ability of HCV to persist in the face of continual immune assault and represents a novel regulatory mechanism that is likely to be found in other viral fusion machinery.
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Affiliation(s)
- Lenka Stejskal
- Institute of Immunity and Transplantation, Division of Infection and Immunity, University College LondonLondonUnited Kingdom
- Institute of Structural and Molecular Biology, Birkbeck CollegeLondonUnited Kingdom
| | - Mphatso D Kalemera
- Institute of Immunity and Transplantation, Division of Infection and Immunity, University College LondonLondonUnited Kingdom
| | - Charlotte B Lewis
- MRC-University of Glasgow Centre for Virus ResearchGlasgowUnited Kingdom
| | - Machaela Palor
- Institute of Immunity and Transplantation, Division of Infection and Immunity, University College LondonLondonUnited Kingdom
| | - Lucas Walker
- Institute of Immunity and Transplantation, Division of Infection and Immunity, University College LondonLondonUnited Kingdom
| | - Tina Daviter
- Institute of Structural and Molecular Biology, Birkbeck CollegeLondonUnited Kingdom
- Shared Research Facilities, The Institute of Cancer ResearchLondonUnited Kingdom
| | - William D Lees
- Institute of Structural and Molecular Biology, Birkbeck CollegeLondonUnited Kingdom
| | - David S Moss
- Institute of Structural and Molecular Biology, Birkbeck CollegeLondonUnited Kingdom
| | | | - Zisis Kozlakidis
- International Agency for Research on Cancer, World Health OrganizationLyonFrance
| | | | | | - William Rosenberg
- Division of Medicine, Institute for Liver and Digestive Health, University College LondonLondonUnited Kingdom
| | - Christopher JR Illingworth
- MRC-University of Glasgow Centre for Virus ResearchGlasgowUnited Kingdom
- Department of Genetics, University of CambridgeCambridgeUnited Kingdom
- Institut für Biologische Physik, Universität zu KölnCologneGermany
- MRC Biostatistics Unit, University of CambridgeCambridgeUnited Kingdom
| | - Adrian J Shepherd
- Institute of Structural and Molecular Biology, Birkbeck CollegeLondonUnited Kingdom
| | - Joe Grove
- Institute of Immunity and Transplantation, Division of Infection and Immunity, University College LondonLondonUnited Kingdom
- MRC-University of Glasgow Centre for Virus ResearchGlasgowUnited Kingdom
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16
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Kirschman J, Marin M, Chen YC, Chen J, Herschhorn A, Smith AB, Melikyan GB. SERINC5 Restricts HIV-1 Infectivity by Promoting Conformational Changes and Accelerating Functional Inactivation of Env. Viruses 2022; 14:1388. [PMID: 35891369 PMCID: PMC9323560 DOI: 10.3390/v14071388] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 06/18/2022] [Accepted: 06/23/2022] [Indexed: 12/16/2022] Open
Abstract
SERINC5 incorporates into HIV-1 particles and inhibits the ability of Env glycoprotein to mediate virus-cell fusion. SERINC5-resistance maps to Env, with primary isolates generally showing greater resistance than laboratory-adapted strains. Here, we examined a relationship between the inhibition of HIV-1 infectivity and the rate of Env inactivation using a panel of SERINC5-resistant and -sensitive HIV-1 Envs. SERINC5 incorporation into pseudoviruses resulted in a faster inactivation of sensitive compared to resistant Env strains. A correlation between fold reduction in infectivity and the rate of inactivation was also observed for multiple Env mutants known to stabilize and destabilize the closed Env structure. Unexpectedly, most mutations disfavoring the closed Env conformation rendered HIV-1 less sensitive to SERINC5. In contrast, functional inactivation of SERINC5-containing viruses was significantly accelerated in the presence of a CD4-mimetic compound, suggesting that CD4 binding sensitizes Env to SERINC5. Using a small molecule inhibitor that selectively targets the closed Env structure, we found that, surprisingly, SERINC5 increases the potency of this compound against a laboratory-adapted Env which prefers a partially open conformation, indicating that SERINC5 may stabilize the closed trimeric Env structure. Our results reveal a complex effect of SERINC5 on Env conformational dynamics that promotes Env inactivation and is likely responsible for the observed restriction phenotype.
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Affiliation(s)
- Junghwa Kirschman
- Department of Pediatrics, Emory University, Atlanta, GA 30322, USA; (J.K.); (M.M.); (Y.-C.C.)
| | - Mariana Marin
- Department of Pediatrics, Emory University, Atlanta, GA 30322, USA; (J.K.); (M.M.); (Y.-C.C.)
- Children’s Healthcare of Atlanta, Atlanta, GA 30322, USA
| | - Yen-Cheng Chen
- Department of Pediatrics, Emory University, Atlanta, GA 30322, USA; (J.K.); (M.M.); (Y.-C.C.)
- Children’s Healthcare of Atlanta, Atlanta, GA 30322, USA
| | - Junhua Chen
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104, USA; (J.C.); (A.B.S.III)
| | - Alon Herschhorn
- Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, MN 55455, USA;
| | - Amos B. Smith
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104, USA; (J.C.); (A.B.S.III)
| | - Gregory B. Melikyan
- Department of Pediatrics, Emory University, Atlanta, GA 30322, USA; (J.K.); (M.M.); (Y.-C.C.)
- Children’s Healthcare of Atlanta, Atlanta, GA 30322, USA
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17
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Abstract
The HIV Env glycoprotein is the surface glycoprotein responsible for viral entry into CD4+ immune cells. During infection, Env also serves as a primary target for antibody responses, which are robust but unable to control virus replication. Immune evasion by HIV-1 Env appears to employ complex mechanisms to regulate what antigenic states are presented to the immune system. Immunodominant features appear to be distinct from epitopes that interfere with Env functions in mediating infection. Further, cell-cell transmission studies indicate that vulnerable conformational states are additionally hidden from recognition on infected cells, even though the presence of Env at the cell surface is required for viral infection through the virological synapse. Cell-cell infection studies support that Env on infected cells is presented in distinct conformations from that on virus particles. Here we review data regarding the regulation of conformational states of Env and assess how regulated sorting of Env within the infected cell may underlie mechanisms to distinguish Env on the surface of virus particles versus Env on the surface of infected cells. These mechanisms may allow infected cells to avoid opsonization, providing cell-to-cell infection by HIV with a selective advantage during evolution within an infected individual. Understanding how distinct Env conformations are presented on cells versus viruses may be essential to designing effective vaccine approaches and therapeutic strategies to clear infected cell reservoirs.
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Affiliation(s)
- Connie Zhao
- Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Hongru Li
- Division of Infectious Diseases, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Talia H. Swartz
- Division of Infectious Diseases, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Benjamin K. Chen
- Division of Infectious Diseases, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA
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18
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A Toxin-Conjugated Recombinant Protein Targeting gp120 and gp41 for Inactivating HIV-1 Virions and Killing Latency-Reversing Agent-Reactivated Latent Cells. mBio 2022; 13:e0338421. [PMID: 35038908 PMCID: PMC8764533 DOI: 10.1128/mbio.03384-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Application of the combination antiretroviral therapy (cART) has reduced AIDS to a manageable chronic infectious disease. However, HIV/AIDS cannot be cured because of the presence of latent reservoirs, thus calling for the development of antiretroviral drugs that can eliminate latency-reversing agent (LRA)-activated HIV-1 virions and latent cells. In this study, we conjugated a small-molecule toxin, DM1, to a gp120-binding protein, mD1.22, a mutated CD4 domain I, and found that mD1.22-DM1 could inactivate HIV-1 virions. However, it could not kill LRA-activated latent cells. We then designed and constructed a dual-targeting protein, DL35D, by linking mD1.22 and the single-chain variable fragment (scFv) of a gp41 NHR-specific antibody, D5, with a 35-mer linker. Subsequently, we conjugated DM1 to DL35D and found that DL35D-DM1 could inhibit HIV-1 infection, inactivate HIV-1 virions, kill HIV-1-infected cells and LRA-reactivated latent cells, suggesting that this toxin-conjugated dual-targeting recombinant protein is a promising candidate for further development as a novel antiviral drug with potential for HIV functional cure. IMPORTANCE Although HIV-1 replication was successfully controlled by antiretroviral drugs, cure strategy for HIV-1/AIDS is still lacking. The long-lived HIV reservoir is considered one of the major obstacles to an HIV/AIDS cure. CD4-PE40 was the first drug that designed to kill HIV-1 infected cells; however, lower efficiency and high immunogenicity have limited its further development. In this study, we designed several dual-targeting recombinant proteins DLDs by linking gp120-binding protein mD1.22 and gp41-binding antibody D5 scFv with different length of linkers. Among them, DL35D with 35-mer linker showed the best anti-HIV-1 activity. We further conjugated the DM1 toxin to DL35D to produce DL35D-DM1, which maintained DL35D's inhibitory and inactivation activity against cell-free HIV-1 strains. Most importantly, DL35D-DM1 could specifically kill HIV-1-infected cells and LRA-reactivated-latent infected cells, suggesting that it is a proper candidate for development as a novel antiviral drug for use in combination with an LRA for HIV functional cure.
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19
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Fritschi C, Liang S, Mohammadi M, Anang S, Moraca F, Chen J, Madani N, Sodroski JG, Abrams CF, Hendrickson WA, Smith AB. Identification of gp120 Residue His105 as a Novel Target for HIV-1 Neutralization by Small-Molecule CD4-Mimics. ACS Med Chem Lett 2021; 12:1824-1831. [PMID: 34795873 PMCID: PMC8591726 DOI: 10.1021/acsmedchemlett.1c00437] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Accepted: 10/21/2021] [Indexed: 01/24/2023] Open
Abstract
The design and synthesis of butyl chain derivatives at the indane ring 3-position of our lead CD4-mimetic compound BNM-III-170 that inhibits human immunodeficiency virus (HIV-1) infection are reported. Optimization efforts were guided by crystallographic and computational analysis of the small-molecule ligands of the Phe43 cavity of the envelope glycoprotein gp120. Biological evaluation of 11-21 revealed that members of this series of CD4-mimetic compounds are able to inhibit HIV-1 viral entry into target cells more potently and with greater breadth compared to BNM-III-170. Crystallographic analysis of the binding pocket of 14, 16, and 17 revealed a novel hydrogen bonding interaction between His105 and a primary hydroxyl group on the butyl side chain. Further optimization of this interaction with the His105 residue holds the promise of more potent CD4-mimetic compounds.
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Affiliation(s)
- Christopher
J. Fritschi
- Department
of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Shuaiyi Liang
- Department of Biochemistry and Molecular Biophysics and Department of Physiology
and Cellular
Biophysics, Columbia University, New York, New York 10032, United States
| | - Mohammadjavad Mohammadi
- Department
of Chemical and Biological Engineering, Drexel University, Philadelphia, Pennsylvania 19104, United States
| | - Saumya Anang
- Department of Cancer
Immunology and Virology, Dana-Farber Cancer
Institute and Department of Microbiology, Harvard Medical
School, Boston, Massachusetts 02115, United States
| | - Francesca Moraca
- Department
of Chemical and Biological Engineering, Drexel University, Philadelphia, Pennsylvania 19104, United States
| | - Junhua Chen
- Department
of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Navid Madani
- Department of Cancer
Immunology and Virology, Dana-Farber Cancer
Institute and Department of Microbiology, Harvard Medical
School, Boston, Massachusetts 02115, United States
| | - Joseph G. Sodroski
- Department of Cancer
Immunology and Virology, Dana-Farber Cancer
Institute and Department of Microbiology, Harvard Medical
School, Boston, Massachusetts 02115, United States
- Department
of Immunology and Infectious Diseases, Harvard
School of Public Health, Boston, Massachusetts 02115, United States
| | - Cameron F. Abrams
- Department
of Chemical and Biological Engineering, Drexel University, Philadelphia, Pennsylvania 19104, United States
| | - Wayne A. Hendrickson
- Department of Biochemistry and Molecular Biophysics and Department of Physiology
and Cellular
Biophysics, Columbia University, New York, New York 10032, United States
| | - Amos B. Smith
- Department
of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
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20
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Kouhpayeh S, Shariati L, Boshtam M, Rahimmanesh I, Mirian M, Esmaeili Y, Najaflu M, Khanahmad N, Zeinalian M, Trovato M, Tay FR, Khanahmad H, Makvandi P. The Molecular Basis of COVID-19 Pathogenesis, Conventional and Nanomedicine Therapy. Int J Mol Sci 2021; 22:5438. [PMID: 34064039 PMCID: PMC8196740 DOI: 10.3390/ijms22115438] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Revised: 05/16/2021] [Accepted: 05/18/2021] [Indexed: 12/12/2022] Open
Abstract
In late 2019, a new member of the Coronaviridae family, officially designated as "severe acute respiratory syndrome coronavirus 2" (SARS-CoV-2), emerged and spread rapidly. The Coronavirus Disease-19 (COVID-19) outbreak was accompanied by a high rate of morbidity and mortality worldwide and was declared a pandemic by the World Health Organization in March 2020. Within the Coronaviridae family, SARS-CoV-2 is considered to be the third most highly pathogenic virus that infects humans, following the severe acute respiratory syndrome coronavirus (SARS-CoV) and the Middle East respiratory syndrome coronavirus (MERS-CoV). Four major mechanisms are thought to be involved in COVID-19 pathogenesis, including the activation of the renin-angiotensin system (RAS) signaling pathway, oxidative stress and cell death, cytokine storm, and endothelial dysfunction. Following virus entry and RAS activation, acute respiratory distress syndrome develops with an oxidative/nitrosative burst. The DNA damage induced by oxidative stress activates poly ADP-ribose polymerase-1 (PARP-1), viral macrodomain of non-structural protein 3, poly (ADP-ribose) glycohydrolase (PARG), and transient receptor potential melastatin type 2 (TRPM2) channel in a sequential manner which results in cell apoptosis or necrosis. In this review, blockers of angiotensin II receptor and/or PARP, PARG, and TRPM2, including vitamin D3, trehalose, tannins, flufenamic and mefenamic acid, and losartan, have been investigated for inhibiting RAS activation and quenching oxidative burst. Moreover, the application of organic and inorganic nanoparticles, including liposomes, dendrimers, quantum dots, and iron oxides, as therapeutic agents for SARS-CoV-2 were fully reviewed. In the present review, the clinical manifestations of COVID-19 are explained by focusing on molecular mechanisms. Potential therapeutic targets, including the RAS signaling pathway, PARP, PARG, and TRPM2, are also discussed in depth.
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Affiliation(s)
- Shirin Kouhpayeh
- Erythron Genetics and Pathobiology Laboratory, Department of Immunology, Isfahan 8164776351, Iran;
| | - Laleh Shariati
- Department of Biomaterials, Nanotechnology and Tissue Engineering, School of Advanced Technologies in Medicine, Isfahan University of Medical Sciences, Isfahan 8174673461, Iran;
- Biosensor Research Center, School of Advanced Technologies in Medicine, Isfahan University of Medical Sciences, Isfahan 8174673461, Iran;
| | - Maryam Boshtam
- Isfahan Cardiovascular Research Center, Cardiovascular Research Institute, Isfahan University of Medical Sciences, Isfahan 8158388994, Iran;
| | - Ilnaz Rahimmanesh
- Applied Physiology Research Center, Cardiovascular Research Institute, Isfahan University of Medical Sciences, Isfahan 8174673461, Iran;
| | - Mina Mirian
- Department of Pharmaceutical Biotechnology, School of Pharmacy and Pharmaceutical Science, Isfahan University of Medical Sciences, Isfahan 8174673461, Iran;
| | - Yasaman Esmaeili
- Biosensor Research Center, School of Advanced Technologies in Medicine, Isfahan University of Medical Sciences, Isfahan 8174673461, Iran;
| | - Malihe Najaflu
- Department of Genetics and Molecular Biology, School of Medicine, Isfahan University of Medical Sciences, Isfahan 8174673461, Iran; (M.N.); (M.Z.)
| | - Negar Khanahmad
- School of Medicine, Isfahan University of Medical Sciences, Isfahan 817467346, Iran;
| | - Mehrdad Zeinalian
- Department of Genetics and Molecular Biology, School of Medicine, Isfahan University of Medical Sciences, Isfahan 8174673461, Iran; (M.N.); (M.Z.)
| | - Maria Trovato
- Institute of Biochemistry and Cell Biology (IBBC), National Research Council (CNR), 80131 Naples, Italy;
| | - Franklin R Tay
- The Graduate School, Augusta University, Augusta, GA 30912, USA;
| | - Hossein Khanahmad
- Department of Genetics and Molecular Biology, School of Medicine, Isfahan University of Medical Sciences, Isfahan 8174673461, Iran; (M.N.); (M.Z.)
| | - Pooyan Makvandi
- Istituto Italiano di Tecnologia, Centre for Materials Interface, viale Rinaldo Piaggio 34, 56025 Pisa, Italy
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21
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Slow Receptor Binding of the Noncytopathic HIV-2 UC1 Envs Is Balanced by Long-Lived Activation State and Efficient Fusion Activity. Cell Rep 2021; 31:107749. [PMID: 32521274 DOI: 10.1016/j.celrep.2020.107749] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Revised: 04/20/2020] [Accepted: 05/18/2020] [Indexed: 01/08/2023] Open
Abstract
Many HIV strains downregulate the levels of CD4 receptor on the surface of infected cells to prevent superinfection. In contrast, the rare HIV-2UC1 strain is noncytopathic and has no effect on CD4 expression in infected cells but still replicates as efficiently as more cytopathic strains in peripheral blood mononuclear cells (PBMCs). Here, we show that HIV-2UC1 Env interactions with the CD4 receptor exhibit slow association kinetics, whereas the dissociation kinetics is within the range of cytopathic strains. Despite the resulting 10- to 100-fold decrease in binding affinity, HIV-2UC1 Envs exhibit long-lived activation state and efficient fusion activity. These observations suggest that HIV-2UC1 Envs evolved to balance low affinity with an improved and readily triggerable molecular machinery to mediate entry. Resistance to cold exposure, similar to many primary HIV-1 isolates, and to sCD4 neutralization suggests that HIV-2UC1 Envs preferentially sample a closed Env conformation. Our data provide insights into the mechanism of HIV entry.
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22
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Synergistic Effect by Combining a gp120-Binding Protein and a gp41-Binding Antibody to Inactivate HIV-1 Virions and Inhibit HIV-1 Infection. Molecules 2021; 26:molecules26071964. [PMID: 33807292 PMCID: PMC8036483 DOI: 10.3390/molecules26071964] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 03/23/2021] [Accepted: 03/25/2021] [Indexed: 11/29/2022] Open
Abstract
Acquired immune deficiency syndrome (AIDS) has prevailed over the last 30 years. Although highly active antiretroviral therapy (HAART) has decreased mortality and efficiently controlled the progression of disease, no vaccine or curative drugs have been approved until now. A viral inactivator is expected to inactivate cell-free virions in the absence of target cells. Previously, we identified a gp120-binding protein, mD1.22, which can inactivate laboratory-adapted HIV-1. In this study, we have found that the gp41 N-terminal heptad repeat (NHR)-binding antibody D5 single-chain variable fragment (scFv) alone cannot inactivate HIV-1 at the high concentration tested. However, D5 scFv in the combination could enhance inactivation activity of mD1.22 against divergent HIV-1 strains, including HIV-1 laboratory-adapted strains, primary HIV-1 isolates, T20- and AZT-resistant strains, and LRA-reactivated virions. Combining mD1.22 and D5 scFv exhibited synergistic effect on inhibition of infection by divergent HIV-1 strains. These results suggest good potential to develop the strategy of combining a gp120-binding protein and a gp41-binding antibody for the treatment of HIV-1 infection.
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23
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Jette CA, Barnes CO, Kirk SM, Melillo B, Smith AB, Bjorkman PJ. Cryo-EM structures of HIV-1 trimer bound to CD4-mimetics BNM-III-170 and M48U1 adopt a CD4-bound open conformation. Nat Commun 2021; 12:1950. [PMID: 33782388 PMCID: PMC8007822 DOI: 10.1038/s41467-021-21816-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Accepted: 02/11/2021] [Indexed: 02/01/2023] Open
Abstract
Human immunodeficiency virus-1 (HIV-1), the causative agent of AIDS, impacts millions of people. Entry into target cells is mediated by the HIV-1 envelope (Env) glycoprotein interacting with host receptor CD4, which triggers conformational changes allowing binding to a coreceptor and subsequent membrane fusion. Small molecule or peptide CD4-mimetic drugs mimic CD4's Phe43 interaction with Env by inserting into the conserved Phe43 pocket on Env subunit gp120. Here, we present single-particle cryo-EM structures of CD4-mimetics BNM-III-170 and M48U1 bound to a BG505 native-like Env trimer plus the CD4-induced antibody 17b at 3.7 Å and 3.9 Å resolution, respectively. CD4-mimetic-bound BG505 exhibits canonical CD4-induced conformational changes including trimer opening, formation of the 4-stranded gp120 bridging sheet, displacement of the V1V2 loop, and formation of a compact and elongated gp41 HR1C helical bundle. We conclude that CD4-induced structural changes on both gp120 and gp41 Env subunits are induced by binding to the gp120 Phe43 pocket.
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Affiliation(s)
- Claudia A. Jette
- grid.20861.3d0000000107068890Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA USA
| | - Christopher O. Barnes
- grid.20861.3d0000000107068890Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA USA
| | - Sharon M. Kirk
- grid.25879.310000 0004 1936 8972Department of Chemistry, University of Pennsylvania, Philadelphia, PA USA
| | - Bruno Melillo
- grid.25879.310000 0004 1936 8972Department of Chemistry, University of Pennsylvania, Philadelphia, PA USA
| | - Amos B. Smith
- grid.25879.310000 0004 1936 8972Department of Chemistry, University of Pennsylvania, Philadelphia, PA USA
| | - Pamela J. Bjorkman
- grid.20861.3d0000000107068890Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA USA
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24
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Tada T, Fan C, Chen JS, Kaur R, Stapleford KA, Gristick H, Dcosta BM, Wilen CB, Nimigean CM, Landau NR. An ACE2 Microbody Containing a Single Immunoglobulin Fc Domain Is a Potent Inhibitor of SARS-CoV-2. Cell Rep 2020; 33:108528. [PMID: 33326798 PMCID: PMC7705358 DOI: 10.1016/j.celrep.2020.108528] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 10/26/2020] [Accepted: 11/24/2020] [Indexed: 12/20/2022] Open
Abstract
Soluble forms of angiotensin-converting enzyme 2 (ACE2) have recently been shown to inhibit severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. We report on an improved soluble ACE2, termed a "microbody," in which the ACE2 ectodomain is fused to Fc domain 3 of the immunoglobulin (Ig) heavy chain. The protein is smaller than previously described ACE2-Ig Fc fusion proteins and contains an H345A mutation in the ACE2 catalytic active site that inactivates the enzyme without reducing its affinity for the SARS-CoV-2 spike. The disulfide-bonded ACE2 microbody protein inhibits entry of SARS-CoV-2 spike protein pseudotyped virus and replication of live SARS-CoV-2 in vitro and in a mouse model. Its potency is 10-fold higher than soluble ACE2, and it can act after virus bound to the cell. The microbody inhibits the entry of β coronaviruses and virus with the variant D614G spike. The ACE2 microbody may be a valuable therapeutic for coronavirus disease 2019 (COVID-19) that is active against viral variants and future coronaviruses.
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Affiliation(s)
- Takuya Tada
- Department of Microbiology, NYU Langone Medical Center, New York, NY 10016, USA
| | - Chen Fan
- Department of Anesthesiology, Weill Cornell Medical College, New York, NY 10065, USA
| | - Jennifer S Chen
- Department of Laboratory Medicine, Yale School of Medicine, New Haven, CT 06520, USA; Department of Immunobiology, Yale School of Medicine, New Haven, CT 06520, USA
| | - Ramanjit Kaur
- Department of Microbiology, NYU Langone Medical Center, New York, NY 10016, USA
| | | | - Harry Gristick
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Belinda M Dcosta
- Department of Microbiology, NYU Langone Medical Center, New York, NY 10016, USA
| | - Craig B Wilen
- Department of Laboratory Medicine, Yale School of Medicine, New Haven, CT 06520, USA; Department of Immunobiology, Yale School of Medicine, New Haven, CT 06520, USA
| | - Crina M Nimigean
- Department of Anesthesiology, Weill Cornell Medical College, New York, NY 10065, USA
| | - Nathaniel R Landau
- Department of Microbiology, NYU Langone Medical Center, New York, NY 10016, USA.
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25
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Differential utilization of CD4+ by transmitted/founder and chronic envelope glycoproteins in a MSM HIV-1 subtype B transmission cluster. AIDS 2020; 34:2187-2200. [PMID: 32932339 DOI: 10.1097/qad.0000000000002690] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE HIV-1 transmission leads to a genetic bottleneck, with one or a few variants of the donor quasispecies establishing an infection in the new host. We aimed to characterize this bottleneck in more detail, by comparing the properties of HIV envelope glycoproteins from acute and chronic infections within the particular context of a male-to-male transmission cluster. DESIGN We compared the genotypic and phenotypic properties of envelope glycoproteins from viral variants derived from five study participants from the same transmission cluster. METHODS We used single-genome amplification to generate a collection of full-length env sequences. We then constructed pseudotyped viruses expressing selected Env variants from the quasispecies infecting each study participant and compared their infectivities and sensitivities to various entry inhibitors. RESULTS The genotypic analyses confirmed the genetic bottleneck expected after HIV transmission, with a limited number of variants identified in four study participants during acute infection. However, the transmitted sequences harbored no evident common signature and belonged to various genetic lineages. The phenotypic analyses revealed no difference in infectivity, susceptibility to the CCR5 antagonist maraviroc, the fusion inhibitor enfurvitide or type-I interferon between viruses from participants with acute and chronic infections. The key property distinguishing transmitted viruses was a higher resistance to soluble CD4, correlated with greater sensitivity to occupation of the CD4 receptor by the anti-CD4 antibodies LM52 and SK3. CONCLUSION These results suggest that envelope glycoproteins from transmitted/founder viruses bind CD4 less efficiently than those of viruses from chronic infections.
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26
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Su X, Wang Q, Wen Y, Jiang S, Lu L. Protein- and Peptide-Based Virus Inactivators: Inactivating Viruses Before Their Entry Into Cells. Front Microbiol 2020; 11:1063. [PMID: 32523582 PMCID: PMC7261908 DOI: 10.3389/fmicb.2020.01063] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2019] [Accepted: 04/29/2020] [Indexed: 12/20/2022] Open
Abstract
Infectious diseases caused by human immunodeficiency virus (HIV) and other highly pathogenic enveloped viruses, have threatened the global public health. Most antiviral drugs act as passive defenders to inhibit viral replication inside the cell, while a few of them function as gate keepers to combat viruses outside the cell, including fusion inhibitors, e.g., enfuvirtide, and receptor antagonists, e.g., maraviroc, as well as virus inactivators (including attachment inhibitors). Different from fusion inhibitors and receptor antagonists that must act in the presence of target cells, virus inactivators can actively inactivate cell-free virions in the blood, through interaction with one or more sites in the envelope glycoproteins (Envs) on virions. Notably, a number of protein- and peptide-based virus inactivators (PPVIs) under development are expected to have a better utilization rate than the current antiviral drugs and be safer for in vivo human application than the chemical-based virus inactivators. Here we have highlighted recent progress in developing PPVIs against several important enveloped viruses, including HIV, influenza virus, Zika virus (ZIKV), dengue virus (DENV), and herpes simplex virus (HSV), and the potential use of PPVIs for urgent treatment of infection by newly emerging or re-emerging viruses.
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Affiliation(s)
- Xiaojie Su
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences, Fudan University, Shanghai, China
| | - Qian Wang
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences, Fudan University, Shanghai, China
| | - Yumei Wen
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences, Fudan University, Shanghai, China
| | - Shibo Jiang
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences, Fudan University, Shanghai, China.,Lindsley F. Kimball Research Institute, New York Blood Center, New York, NY, United States
| | - Lu Lu
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences, Fudan University, Shanghai, China
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27
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The Conformational States of the HIV-1 Envelope Glycoproteins. Trends Microbiol 2020; 28:655-667. [PMID: 32418859 DOI: 10.1016/j.tim.2020.03.007] [Citation(s) in RCA: 55] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Accepted: 03/25/2020] [Indexed: 12/16/2022]
Abstract
During HIV-1 entry into target cells, binding of the virus to host receptors, CD4 and CCR5/CXCR4, triggers serial conformational changes in the envelope glycoprotein (Env) trimer that result in the fusion of the viral and cell membranes. Recent discoveries have refined our knowledge of Env conformational states, allowing characterization of the targets of small-molecule HIV-1 entry inhibitors and neutralizing antibodies, and identifying a novel off-pathway conformation (State 2A). Here, we provide an overview of the current understanding of these conformational states, focusing on (i) the events during HIV-1 entry; (ii) conformational preferences of HIV-1 Env ligands; (iii) evasion of the host antibody response; and (iv) potential implications for therapy and prevention of HIV-1 infection.
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28
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Johnson J, Flores MG, Rosa J, Han C, Salvi AM, DeMali KA, Jagnow JR, Sparks A, Haim H. The High Content of Fructose in Human Semen Competitively Inhibits Broad and Potent Antivirals That Target High-Mannose Glycans. J Virol 2020; 94:e01749-19. [PMID: 32102878 PMCID: PMC7163146 DOI: 10.1128/jvi.01749-19] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Accepted: 02/17/2020] [Indexed: 11/20/2022] Open
Abstract
Semen is the primary transmission vehicle for various pathogenic viruses. Initial steps of transmission, including cell attachment and entry, likely occur in the presence of semen. However, the unstable nature of human seminal plasma and its toxic effects on cells in culture limit the ability to study in vitro virus infection and inhibition in this medium. We found that whole semen significantly reduces the potency of antibodies and microbicides that target glycans on the envelope glycoproteins (Envs) of HIV-1. The extraordinarily high concentration of the monosaccharide fructose in semen contributes significantly to the effect by competitively inhibiting the binding of ligands to α1,2-linked mannose residues on Env. Infection and inhibition in whole human seminal plasma are accurately mimicked by a stable synthetic simulant of seminal fluid that we formulated. Our findings indicate that, in addition to the protein content of biological secretions, their small-solute composition impacts the potency of antiviral microbicides and mucosal antibodies.IMPORTANCE Biological secretions allow viruses to spread between individuals. Each type of secretion has a unique composition of proteins, salts, and sugars, which can affect the infectivity potential of the virus and inhibition of this process. Here, we describe HIV-1 infection and inhibition in whole human seminal plasma and a synthetic simulant that we formulated. We discovered that the sugar fructose in semen decreases the activity of a broad and potent class of antiviral agents that target mannose sugars on the envelope protein of HIV-1. This effect of semen fructose likely reduces the efficacy of such inhibitors to prevent the sexual transmission of HIV-1. Our findings suggest that the preclinical evaluation of microbicides and vaccine-elicited antibodies will be improved by their in vitro assessment in synthetic formulations that simulate the effects of semen on HIV-1 infection and inhibition.
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Affiliation(s)
- Jacklyn Johnson
- Department of Microbiology and Immunology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Manuel G Flores
- Department of Microbiology and Immunology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - John Rosa
- Department of Microbiology and Immunology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Changze Han
- Department of Microbiology and Immunology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Alicia M Salvi
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Kris A DeMali
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Jennifer R Jagnow
- In Vitro Fertilization and Reproductive Testing Laboratory, University of Iowa Hospitals and Clinics, Iowa City, Iowa, USA
| | - Amy Sparks
- In Vitro Fertilization and Reproductive Testing Laboratory, University of Iowa Hospitals and Clinics, Iowa City, Iowa, USA
| | - Hillel Haim
- Department of Microbiology and Immunology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
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29
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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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30
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Ding S, Grenier MC, Tolbert WD, Vézina D, Sherburn R, Richard J, Prévost J, Chapleau JP, Gendron-Lepage G, Medjahed H, Abrams C, Sodroski J, Pazgier M, Smith AB, Finzi A. A New Family of Small-Molecule CD4-Mimetic Compounds Contacts Highly Conserved Aspartic Acid 368 of HIV-1 gp120 and Mediates Antibody-Dependent Cellular Cytotoxicity. J Virol 2019; 93:e01325-19. [PMID: 31554684 PMCID: PMC6880173 DOI: 10.1128/jvi.01325-19] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Accepted: 09/18/2019] [Indexed: 12/20/2022] Open
Abstract
The HIV-1 envelope glycoprotein (Env) trimer mediates virus entry into cells. The "closed" conformation of Env is resistant to nonneutralizing antibodies (nnAbs). These antibodies mostly recognize occluded epitopes that can be exposed upon binding of CD4 or small-molecule CD4 mimetics (CD4mc). Here, we describe a new family of small molecules that expose Env to nnAbs and sensitize infected cells to antibody-dependent cellular cytotoxicity (ADCC). These compounds have a limited capacity to inhibit virus infection directly but are able to sensitize viral particles to neutralization by otherwise nonneutralizing antibodies. Structural analysis shows that some analogs of this family of CD4mc engage the gp120 Phe43 cavity by contacting the highly conserved D368 residue, making them attractive scaffolds for drug development.IMPORTANCE HIV-1 has evolved multiple strategies to avoid humoral responses. One efficient mechanism is to keep its envelope glycoprotein (Env) in its "closed" conformation. Here, we report on a new family of small molecules that are able to "open up" Env, thus exposing vulnerable epitopes. This new family of molecules binds in the Phe43 cavity and contacts the highly conserved D368 residue. The structural and biological attributes of molecules of this family make them good candidates for drug development.
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Affiliation(s)
- Shilei Ding
- Centre de Recherche du CHUM, Montreal, Quebec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, Quebec, Canada
| | - Melissa C Grenier
- Department of Chemistry, School of Arts and Sciences, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - William D Tolbert
- Infectious Diseases Division, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Dani Vézina
- Centre de Recherche du CHUM, Montreal, Quebec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, Quebec, Canada
| | - Rebekah Sherburn
- Infectious Diseases Division, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Jonathan Richard
- Centre de Recherche du CHUM, Montreal, Quebec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, Quebec, Canada
| | - Jérémie Prévost
- Centre de Recherche du CHUM, Montreal, Quebec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, Quebec, Canada
| | - Jean-Philippe Chapleau
- Centre de Recherche du CHUM, Montreal, Quebec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, Quebec, Canada
| | | | | | - Cameron Abrams
- Department of Chemical and Biological Engineering, Drexel University, Philadelphia, Pennsylvania, 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
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, Massachusetts, USA
| | - Marzena Pazgier
- Infectious Diseases Division, 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, Montreal, Quebec, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, Quebec, Canada
- Department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada
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Salimi H, Johnson J, Flores MG, Zhang MS, O'Malley Y, Houtman JC, Schlievert PM, Haim H. The lipid membrane of HIV-1 stabilizes the viral envelope glycoproteins and modulates their sensitivity to antibody neutralization. J Biol Chem 2019; 295:348-362. [PMID: 31757809 DOI: 10.1074/jbc.ra119.009481] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 11/19/2019] [Indexed: 11/06/2022] Open
Abstract
The envelope glycoproteins (Envs) of HIV-1 are embedded in the cholesterol-rich lipid membrane of the virus. Chemical depletion of cholesterol from HIV-1 particles inactivates their infectivity. We observed that diverse HIV-1 strains exhibit a range of sensitivities to such treatment. Differences in sensitivity to cholesterol depletion could not be explained by variation in Env components known to interact with cholesterol, including the cholesterol-recognition motif and cytoplasmic tail of gp41. Using antibody-binding assays, measurements of virus infectivity, and analyses of lipid membrane order, we found that depletion of cholesterol from HIV-1 particles decreases the conformational stability of Env. It enhances exposure of partially cryptic epitopes on the trimer and increases sensitivity to structure-perturbing treatments such as antibodies and cold denaturation. Substitutions in the cholesterol-interacting motif of gp41 induced similar effects as depletion of cholesterol. Surface-acting agents, which are incorporated into the virus lipid membrane, caused similar effects as disruption of the Env-cholesterol interaction. Furthermore, substitutions in gp120 that increased structural stability of Env (i.e. induced a "closed" conformation of the trimer) increased virus resistance to cholesterol depletion and to the surface-acting agents. Collectively, these results indicate a critical contribution of the viral membrane to the stability of the Env trimer and to neutralization resistance against antibodies. Our findings suggest that the potency of poorly neutralizing antibodies, which are commonly elicited in vaccinated individuals, may be markedly enhanced by altering the lipid composition of the viral membrane.
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Affiliation(s)
- Hamid Salimi
- Department of Microbiology and Immunology, Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242
| | - Jacklyn Johnson
- Department of Microbiology and Immunology, Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242
| | - Manuel G Flores
- Department of Microbiology and Immunology, Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242
| | - Michael S Zhang
- Department of Microbiology and Immunology, Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242
| | - Yunxia O'Malley
- Department of Microbiology and Immunology, Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242
| | - Jon C Houtman
- Department of Microbiology and Immunology, Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242
| | - Patrick M Schlievert
- Department of Microbiology and Immunology, Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242
| | - Hillel Haim
- Department of Microbiology and Immunology, Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242.
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32
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Zhao C, Princiotto AM, Nguyen HT, Zou S, Zhao ML, Zhang S, Herschhorn A, Farrell M, Pahil K, Melillo B, Sambasivarao SV, Abrams C, Smith AB, Madani N, Sodroski J. Strain-Dependent Activation and Inhibition of Human Immunodeficiency Virus Entry by a Specific PF-68742 Stereoisomer. J Virol 2019; 93:e01197-19. [PMID: 31391272 PMCID: PMC6803283 DOI: 10.1128/jvi.01197-19] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Accepted: 08/03/2019] [Indexed: 12/27/2022] Open
Abstract
Human immunodeficiency virus (HIV-1) entry into cells is mediated by the viral envelope glycoprotein (Env) trimer, which consists of three gp120 exterior glycoproteins and three gp41 transmembrane glycoproteins. When gp120 binds sequentially to the receptors CD4 and CCR5 on the target cell, the metastable Env trimer is triggered to undergo entry-related conformational changes. PF-68742 is a small molecule that inhibits the infection of a subset of HIV-1 strains by interfering with an Env function other than receptor binding. Determinants of HIV-1 resistance to PF-68742 map to the disulfide loop and fusion peptide of gp41. Of the four possible PF-68742 stereoisomers, only one, MF275, inhibited the infection of CD4-positive CCR5-positive cells by some HIV-1 strains. MF275 inhibition of these HIV-1 strains occurred after CD4 binding but before the formation of the gp41 six-helix bundle. Unexpectedly, MF275 activated the infection of CD4-negative CCR5-positive cells by several HIV-1 strains resistant to the inhibitory effects of the compound in CD4-positive target cells. In contrast to CD4 complementation by CD4-mimetic compounds, activation of CD4-independent infection by MF275 did not depend upon the availability of the gp120 Phe 43 cavity. Sensitivity to inhibitors indicates that MF275-activated virus entry requires formation/exposure of the gp41 heptad repeat (HR1) as well as CCR5 binding. MF275 apparently activates a virus entry pathway parallel to that triggered by CD4 and CD4-mimetic compounds. Strain-dependent divergence in Env conformational transitions allows different outcomes, inhibition or activation, in response to MF275. Understanding the mechanisms of MF275 activity should assist efforts to optimize its utility.IMPORTANCE Envelope glycoprotein (Env) spikes on the surface of human immunodeficiency virus (HIV-1) bind target cell receptors, triggering changes in the shape of Env. We studied a small molecule, MF275, that also induced shape changes in Env. The consequences of MF275 interaction with Env depended on the HIV-1 strain, with infection by some viruses inhibited and infection by other viruses enhanced. These studies reveal the strain-dependent diversity of HIV-1 Envs as they undergo shape changes in proceeding down the entry pathway. Appreciation of this diversity will assist attempts to develop broadly active inhibitors of HIV-1 entry.
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Affiliation(s)
- Connie Zhao
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
| | - Amy M Princiotto
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
| | - Hanh T Nguyen
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
| | - Shitao Zou
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
| | - Meiqing Lily Zhao
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
| | - Shijian Zhang
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
| | - Alon Herschhorn
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
- Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, Minnesota, USA
| | - Mark Farrell
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Karanbir Pahil
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Bruno Melillo
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Somisetti V Sambasivarao
- Department of Chemical and Biological Engineering, Drexel University, Philadelphia, Pennsylvania, USA
| | - Cameron Abrams
- Department of Chemical and Biological Engineering, Drexel University, Philadelphia, Pennsylvania, USA
| | - Amos B Smith
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Navid Madani
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, 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
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, Massachusetts, USA
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33
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Pu J, Wang Q, Xu W, Lu L, Jiang S. Development of Protein- and Peptide-Based HIV Entry Inhibitors Targeting gp120 or gp41. Viruses 2019; 11:v11080705. [PMID: 31374953 PMCID: PMC6722851 DOI: 10.3390/v11080705] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Revised: 07/26/2019] [Accepted: 07/26/2019] [Indexed: 01/08/2023] Open
Abstract
Application of highly active antiretroviral drugs (ARDs) effectively reduces morbidity and mortality in HIV-infected individuals. However, the emergence of multiple drug-resistant strains has led to the increased failure of ARDs, thus calling for the development of anti-HIV drugs with targets or mechanisms of action different from those of the current ARDs. The first peptide-based HIV entry inhibitor, enfuvirtide, was approved by the U.S. FDA in 2003 for treatment of HIV/AIDS patients who have failed to respond to the current ARDs, which has stimulated the development of several series of protein- and peptide-based HIV entry inhibitors in preclinical and clinical studies. In this review, we highlighted the properties and mechanisms of action for those promising protein- and peptide-based HIV entry inhibitors targeting the HIV-1 gp120 or gp41 and discussed their advantages and disadvantages, compared with the current ARDs.
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Affiliation(s)
- Jing Pu
- Shanghai Public Health Clinical Center and School of Basic Medical Sciences, Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), Fudan University, Shanghai 200032, China
| | - Qian Wang
- Shanghai Public Health Clinical Center and School of Basic Medical Sciences, Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), Fudan University, Shanghai 200032, China
| | - Wei Xu
- Shanghai Public Health Clinical Center and School of Basic Medical Sciences, Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), Fudan University, Shanghai 200032, China
| | - Lu Lu
- Shanghai Public Health Clinical Center and School of Basic Medical Sciences, Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), Fudan University, Shanghai 200032, China.
| | - Shibo Jiang
- Shanghai Public Health Clinical Center and School of Basic Medical Sciences, Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), Fudan University, Shanghai 200032, China.
- Lindsley F. Kimball Research Institute, New York Blood Center, New York, NY 10065, USA.
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34
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Weiss RA, Verrips CT. Nanobodies that Neutralize HIV. Vaccines (Basel) 2019; 7:vaccines7030077. [PMID: 31370301 PMCID: PMC6789485 DOI: 10.3390/vaccines7030077] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Revised: 07/22/2019] [Accepted: 07/26/2019] [Indexed: 11/16/2022] Open
Abstract
Nanobodies or VHH (variable domains of heavy-chain only antibodies) are derived from camelid species such as llamas and camels. Nanobodies isolated and selected through phage display can neutralize a broad range of human immunodeficiency virus type 1 (HIV-1) strains. Nanobodies fit into canyons on the HIV envelope that may not be accessible to IgG (immunoglobulin G) containing both heavy and light chains, and they tend to have long CDR3 (complementarity-determining region 3) loops that further enhance recognition of otherwise cryptic epitopes. Nanobodies are readily expressed at high levels in bacteria and yeast, as well as by viral vectors, and they form relatively stable, heat-resistant molecules. Nanobodies can be linked to human Fc chains to gain immune effector functions. Bivalent and trivalent nanobodies recognizing the same or distinct epitopes on the envelope glycoproteins, gp120 and gp41, greatly increase the potency of HIV-1 neutralization. Nanobodies have potential applications for HIV-1 diagnostics, vaccine design, microbicides, immunoprophylaxis, and immunotherapy.
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Affiliation(s)
- Robin A Weiss
- Division of Infection & Immunity, University College London, 90 Gower Street, London WC1E 6BT, UK.
| | - C Theo Verrips
- QVQ Holding bv, Padualaan 8, 3584 CL Utrecht, The Netherlands.
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Abstract
As the HIV pandemic rapidly spread worldwide in the 1980s and 1990s, a new approach to treat cancer, genetic diseases, and infectious diseases was also emerging. Cell and gene therapy strategies are connected with human pathologies at a fundamental level, by delivering DNA and RNA molecules that could correct and/or ameliorate the underlying genetic factors of any illness. The history of HIV gene therapy is especially intriguing, in that the virus that was targeted was soon co-opted to become part of the targeting strategy. Today, HIV-based lentiviral vectors, along with many other gene delivery strategies, have been used to evaluate HIV cure approaches in cell culture, small and large animal models, and in patients. Here, we trace HIV cell and gene therapy from the earliest clinical trials, using genetically unmodified cell products from the patient or from matched donors, through current state-of-the-art strategies. These include engineering HIV-specific immunity in T-cells, gene editing approaches to render all blood cells in the body HIV-resistant, and most importantly, combination therapies that draw from both of these respective "offensive" and "defensive" approaches. It is widely agreed upon that combinatorial approaches are the most promising route to functional cure/remission of HIV infection. This chapter outlines cell and gene therapy strategies that are poised to play an essential role in eradicating HIV-infected cells in vivo.
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36
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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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37
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Conformational Differences between Functional Human Immunodeficiency Virus Envelope Glycoprotein Trimers and Stabilized Soluble Trimers. J Virol 2019; 93:JVI.01709-18. [PMID: 30429345 DOI: 10.1128/jvi.01709-18] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Accepted: 11/07/2018] [Indexed: 01/11/2023] Open
Abstract
Binding to the receptor CD4 triggers entry-related conformational changes in the human immunodeficiency virus type 1 (HIV-1) envelope glycoprotein (Env) trimer, (gp120/gp41)3 Soluble versions of HIV-1 Env trimers (sgp140 SOSIP.664) stabilized by a gp120-gp41 disulfide bond and a change (I559P) in gp41 have been structurally characterized. Here, we use cross-linking/mass spectrometry to evaluate the conformations of functional membrane Env and sgp140 SOSIP.664. Differences were detected in the gp120 trimer association domain and C terminus and in the gp41 heptad repeat 1 (HR1) region. Whereas the membrane Env trimer exposes the gp41 HR1 coiled coil only after CD4 binding, the sgp140 SOSIP.664 HR1 coiled coil was accessible to the gp41 HR2 peptide even in the absence of CD4. Our results delineate differences in both gp120 and gp41 subunits between functional membrane Env and the sgp140 SOSIP.664 trimer and provide distance constraints that can assist validation of candidate structural models of the native HIV-1 Env trimer.IMPORTANCE HIV-1 envelope glycoprotein spikes mediate the entry of the virus into host cells and are a major target for vaccine-induced antibodies. Soluble forms of the envelope glycoproteins that are stable and easily produced have been characterized extensively and are being considered as vaccines. Here, we present evidence that these stabilized soluble envelope glycoproteins differ in multiple respects from the natural HIV-1 envelope glycoproteins. By pinpointing these differences, our results can guide the improvement of envelope glycoprotein preparations to achieve greater similarity to the viral envelope glycoprotein spike, potentially increasing their effectiveness as a vaccine.
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38
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Ivan B, Sun Z, Subbaraman H, Friedrich N, Trkola A. CD4 occupancy triggers sequential pre-fusion conformational states of the HIV-1 envelope trimer with relevance for broadly neutralizing antibody activity. PLoS Biol 2019; 17:e3000114. [PMID: 30650070 PMCID: PMC6351000 DOI: 10.1371/journal.pbio.3000114] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Revised: 01/29/2019] [Accepted: 01/04/2019] [Indexed: 12/18/2022] Open
Abstract
During the entry process, the human immunodeficiency virus type 1 (HIV-1) envelope glycoprotein (Env) trimer undergoes a sequence of conformational changes triggered by both CD4 and coreceptor engagement. Resolving the conformation of these transient entry intermediates has proven challenging. Here, we fine-mapped the antigenicity of entry intermediates induced by increasing CD4 engagement of cell surface–expressed Env. Escalating CD4 triggering led to the sequential adoption of different pre-fusion conformational states of the Env trimer, up to the pre-hairpin conformation, that we assessed for antibody epitope presentation. Maximal accessibility of the coreceptor binding site was detected below Env saturation by CD4. Exposure of the fusion peptide and heptad repeat 1 (HR1) required higher CD4 occupancy. Analyzing the diverse antigenic states of the Env trimer, we obtained key insights into the transitions in epitope accessibility of broadly neutralizing antibodies (bnAbs). Several bnAbs preferentially bound CD4-triggered Env, indicating a potential capacity to neutralize both pre- and post-CD4 engagement, which needs to be explored. Assessing binding and neutralization activity of bnAbs, we confirm antibody dissociation rates as a driver of incomplete neutralization. Collectively, our findings highlight a need to resolve Env conformations that are neutralization-relevant to provide guidance for immunogen development. Comprehensive mapping of conformational stages adopted by the HIV‐1 envelope glycoprotein trimer during entry into the cell reveals the preference of broadly neutralizing antibodies for distinct pre-fusion states of the trimer. The trimeric human immunodeficiency virus type 1 (HIV-1) envelope glycoprotein (Env) mediates HIV-1 entry into its target cells. Entry is initiated by sequential triggering of Env upon interaction with its primary receptor CD4 and a coreceptor on target cells. The ensuing structural rearrangements of the Env trimer bring the viral membrane in close vicinity of the cellular membrane, enabling fusion. Resolving the structural differences between the consecutive conformations Env adopts during the entry process is of high interest, as different antigenic domains are exposed, which may affect the capacity of neutralizing antibodies to bind to Env and inhibit entry. Here, we compared the conformation of unliganded closed Env with the transitional CD4-bound Env forms by studying the antigenicity of cell surface–expressed Env with and without CD4 triggering. We show that incremental triggering by soluble CD4 allows the capture of the full continuum of conformational changes, including events that follow coreceptor interaction. Thus, the setup we introduce here turns a simple binding assay into a powerful tool to study transitional conformation changes in HIV-1 Env. Analyzing the capacity of Env-reactive antibodies to recognize the diverse Env stages, our study reveals novel aspects of the binding preferences of neutralizing antibodies that affect their inhibitory activity.
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Affiliation(s)
- Branislav Ivan
- Institute of Medical Virology, University of Zurich, Zurich, Switzerland
| | - Zhaozhi Sun
- Institute of Medical Virology, University of Zurich, Zurich, Switzerland
| | - Harini Subbaraman
- Institute of Medical Virology, University of Zurich, Zurich, Switzerland
| | - Nikolas Friedrich
- Institute of Medical Virology, University of Zurich, Zurich, Switzerland
| | - Alexandra Trkola
- Institute of Medical Virology, University of Zurich, Zurich, Switzerland
- * E-mail:
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Highlights from the Fourth Biennial Strategies for an HIV Cure Meeting, 10–12 October 2018, Bethesda, MD, USA. J Virus Erad 2019. [DOI: 10.1016/s2055-6640(20)30280-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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40
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Kuo L, Lawrence D, McDonald D, Refsland E, Bridges S, Smiley S, Tressler RL, Beaubien C, Salzwedel K. Highlights from the Fourth Biennial Strategies for an HIV Cure Meeting, 10-12 October 2018, Bethesda, MD, USA. J Virus Erad 2019; 5:50-59. [PMID: 30800428 PMCID: PMC6362907] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The National Institute of Allergy and Infectious Diseases (NIAID) organised the Strategies for an HIV Cure 2018 meeting focused on research to develop innovative strategies for eradicating or achieving long-term remission of HIV infection. The purpose was to bring together researchers studying HIV persistence and cure strategies, including the six National Institutes of Health (NIH)-funded Martin Delaney Collaboratories for HIV Cure Research (MDCs), as well as industry and community partners, to share scientific results and stimulate active discussion among all stakeholders about the merits of various approaches under investigation. These discussions were intended to stimulate new collaborations and ideas for future research. The meeting covered a comprehensive range of topics spanning basic and translational research, drug discovery and development, and clinical research. Aside from the oral presentations described here, the meeting also included 130 poster presentations. Each of the three days of presentations is available for viewing via the NIH VideoCast website at: https://videocast.nih.gov/PastEvents.asp.
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Affiliation(s)
- Lillian Kuo
- Division of AIDS,
National Institute of Allergy and Infectious Diseases,
Bethesda,
MD,
USA
| | - Diane Lawrence
- Division of AIDS,
National Institute of Allergy and Infectious Diseases,
Bethesda,
MD,
USA
| | - David McDonald
- Division of AIDS,
National Institute of Allergy and Infectious Diseases,
Bethesda,
MD,
USA
| | - Eric Refsland
- Division of AIDS,
National Institute of Allergy and Infectious Diseases,
Bethesda,
MD,
USA
| | - Sandra Bridges
- Division of AIDS,
National Institute of Allergy and Infectious Diseases,
Bethesda,
MD,
USA
| | - Stephen Smiley
- Division of AIDS,
National Institute of Allergy and Infectious Diseases,
Bethesda,
MD,
USA
| | - Randall L Tressler
- Division of AIDS,
National Institute of Allergy and Infectious Diseases,
Bethesda,
MD,
USA
| | - Candice Beaubien
- Division of AIDS,
National Institute of Allergy and Infectious Diseases,
Bethesda,
MD,
USA
| | - Karl Salzwedel
- Division of AIDS,
National Institute of Allergy and Infectious Diseases,
Bethesda,
MD,
USA
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41
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Joseph JA, Wales DJ. Intrinsically Disordered Landscapes for Human CD4 Receptor Peptide. J Phys Chem B 2018; 122:11906-11921. [DOI: 10.1021/acs.jpcb.8b08371] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Affiliation(s)
- Jerelle A. Joseph
- Department of Chemistry, University of Cambridge, Lenfield Road, Cambridge CB2 1EW, United Kingdom
| | - David J. Wales
- Department of Chemistry, University of Cambridge, Lenfield Road, Cambridge CB2 1EW, United Kingdom
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Falkenhagen A, Joshi S. HIV Entry and Its Inhibition by Bifunctional Antiviral Proteins. MOLECULAR THERAPY-NUCLEIC ACIDS 2018; 13:347-364. [PMID: 30340139 PMCID: PMC6197789 DOI: 10.1016/j.omtn.2018.09.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Revised: 09/05/2018] [Accepted: 09/05/2018] [Indexed: 12/14/2022]
Abstract
HIV entry is a highly specific and time-sensitive process that can be divided into receptor binding, coreceptor binding, and membrane fusion. Bifunctional antiviral proteins (bAVPs) exploit the multi-step nature of the HIV entry process by binding to two different extracellular targets. They are generated by expressing a fusion protein containing two entry inhibitors with a flexible linker. The resulting fusion proteins exhibit exceptional neutralization potency and broad cross-clade inhibition. In this review, we summarize the HIV entry process and provide an overview of the design, antiviral potency, and methods of delivery of bAVPs. Additionally, we discuss the advantages and limitations of bAVPs for HIV prevention and treatment.
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Affiliation(s)
- Alexander Falkenhagen
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 3E2, Canada
| | - Sadhna Joshi
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 3E2, Canada.
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43
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Princiotto AM, Vrbanac VD, Melillo B, Park J, Tager AM, Smith AB, Sodroski J, Madani N. A Small-Molecule CD4-Mimetic Compound Protects Bone Marrow-Liver-Thymus Humanized Mice From HIV-1 Infection. J Infect Dis 2018; 218:471-475. [PMID: 29617845 PMCID: PMC6049021 DOI: 10.1093/infdis/jiy174] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Accepted: 03/28/2018] [Indexed: 11/13/2022] Open
Abstract
Background Small-molecule CD4-mimetic compounds (CD4mc) inhibit human immunodeficiency virus (HIV-1) entry by blocking binding to the CD4 receptor and by premature triggering of the viral envelope glycoprotein (Env) spike. Methods The efficacy of a CD4mc in protecting bone marrow-liver-thymus (BLT) humanized mice from vaginal HIV-1 challenge was evaluated. Results Intravaginal application of the CD4mc JP-III-48, either before or simultaneously with virus challenge, protected BLT humanized mice from HIV-1JR-CSF infection in a dose- dependent manner. Conclusion The direct antiviral effects of a CD4mc prevent HIV-1 infection in a murine model of sexual transmission.
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Affiliation(s)
- Amy M Princiotto
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, Massachusetts
| | - Vladimir D Vrbanac
- Center for Immunology and Inflammatory Diseases, Division of Rheumatology, Allergy and Immunology, Massachusetts General Hospital, Boston, Massachusetts
| | - Bruno Melillo
- Department of Chemistry, University of Pennsylvania, Philadelphia
| | - Jongwoo Park
- Department of Chemistry, University of Pennsylvania, Philadelphia
| | - Andrew M Tager
- Center for Immunology and Inflammatory Diseases, Division of Rheumatology, Allergy and Immunology, Massachusetts General Hospital, Boston, Massachusetts
| | - Amos B Smith
- Department of Chemistry, University of Pennsylvania, Philadelphia
| | - Joseph Sodroski
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, Massachusetts
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, Massachusetts
| | - Navid Madani
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, Massachusetts
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts
- Department of Global Health and Social Medicine, Harvard Medical School, Boston, Massachusetts
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Restricted HIV-1 Env glycan engagement by lectin-reengineered DAVEI protein chimera is sufficient for lytic inactivation of the virus. Biochem J 2018; 475:931-957. [PMID: 29343613 DOI: 10.1042/bcj20170662] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2017] [Revised: 12/28/2017] [Accepted: 01/17/2018] [Indexed: 12/28/2022]
Abstract
We previously reported a first-generation recombinant DAVEI construct, a dual action virus entry inhibitor composed of cyanovirin-N (CVN) fused to a membrane proximal external region or its derivative peptide Trp3. DAVEI exhibits potent and irreversible inactivation of HIV-1 (human immunodeficiency virus) viruses by dual engagement of gp120 and gp41. However, the promiscuity of CVN to associate with multiple glycosylation sites in gp120 and its multivalency limit current understanding of the molecular arrangement of the DAVEI molecules on trimeric spike. Here, we constructed and investigated the virolytic function of second-generation DAVEI molecules using a simpler lectin, microvirin (MVN). MVN is a monovalent lectin with a single glycan-binding site in gp120, is structurally similar to CVN and exhibits no toxicity or mitogenicity, both of which are liabilities with CVN. We found that, like CVN-DAVEI-L2-3Trp (peptide sequence DKWASLWNW), MVN-DAVEI2-3Trp exploits a similar mechanism of action for inducing HIV-1 lytic inactivation, but by more selective gp120 glycan engagement. By sequence redesign, we significantly increased the potency of MVN-DAVEI2-3Trp protein. Unlike CVN-DAVEI2-3Trp, re-engineered MVN-DAVEI2-3Trp(Q81K/M83R) virolytic activity and its interaction with gp120 were both competed by 2G12 antibody. That the lectin domain in DAVEIs can utilize MVN without loss of virolytic function argues that restricted HIV-1 Env (envelope glycoprotein) glycan engagement is sufficient for virolysis. It also shows that DAVEI lectin multivalent binding with gp120 is not required for virolysis. MVN-DAVEI2-3Trp(Q81K/M83R) provides an improved tool to elucidate productive molecular arrangements of Env-DAVEI enabling virolysis and also opens the way to form DAVEI fusions made up of gp120-binding small molecules linked to Trp3 peptide.
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Control of HIV Infection In Vivo Using Gene Therapy with a Secreted Entry Inhibitor. MOLECULAR THERAPY. NUCLEIC ACIDS 2017; 9:132-144. [PMID: 29246292 PMCID: PMC5633861 DOI: 10.1016/j.omtn.2017.08.017] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 08/29/2017] [Accepted: 08/29/2017] [Indexed: 11/22/2022]
Abstract
HIV entry inhibitors are highly effective in controlling virus replication. We have developed a lentiviral vector that expresses a secreted entry inhibitor, soluble CD4 (sCD4), which binds to the HIV envelope glycoproteins and inactivates the virus. We have shown that sCD4 was secreted from gene-modified CD4+ T cells, as well as from human umbilical cord blood-derived CD34+ hematopoietic stem/progenitor cells (HSPCs), and protected unmodified HIV target cells from infection in vitro. To investigate the in vivo application of our approach, we injected gene-modified HSPCs into NOD/SCID/γcnull (NSG) mice. NSG hosts supported multi-lineage differentiation of human gene-modified HSPCs. Upon challenge with HIV, humanized mice capable of secreting sCD4 demonstrated a reduction of viral load over time compared to control humanized mice. In contrast to gene therapy approaches that render only gene-modified HIV target cells resistant to infection, our approach also showed protection of unmodified CD4+ T cells in the peripheral blood and tissues. Our findings provide support for the continuous delivery of secreted entry inhibitors via gene therapy as an alternative to oral administration of antiretroviral drugs or injection of antiretroviral proteins, including antibodies.
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Induction of a Tier-1-Like Phenotype in Diverse Tier-2 Isolates by Agents That Guide HIV-1 Env to Perturbation-Sensitive, Nonnative States. J Virol 2017; 91:JVI.00174-17. [PMID: 28490588 DOI: 10.1128/jvi.00174-17] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Accepted: 04/24/2017] [Indexed: 01/05/2023] Open
Abstract
The envelope glycoproteins (Envs) on the surfaces of HIV-1 particles are targeted by host antibodies. Primary HIV-1 isolates demonstrate different global sensitivities to antibody neutralization; tier-1 isolates are sensitive, whereas tier-2 isolates are more resistant. Single-site mutations in Env can convert tier-2 into tier-1-like viruses. We hypothesized that such global change in neutralization sensitivity results from weakening of intramolecular interactions that maintain Env integrity. Three strategies commonly applied to perturb protein structure were tested for their effects on global neutralization sensitivity: exposure to low temperature, Env-activating ligands, and a chaotropic agent. A large panel of diverse tier-2 isolates from clades B and C was analyzed. Incubation at 0°C, which globally weakens hydrophobic interactions, causes gradual and reversible exposure of the coreceptor-binding site. In the cold-induced state, Envs progress at isolate-specific rates to unstable forms that are sensitive to antibody neutralization and then gradually lose function. Agents that mimic the effects of CD4 (CD4Ms) also induce reversible structural changes to states that exhibit isolate-specific stabilities. The chaotropic agent urea (at low concentrations) does not affect the structure or function of native Env. However, urea efficiently perturbs metastable states induced by cold and CD4Ms and increases their sensitivity to antibody neutralization and their inactivation rates Therefore, chemical and physical agents can guide Env from the stable native state to perturbation-sensitive forms and modulate their stability to bestow tier-1-like properties on primary tier-2 strains. These concepts can be applied to enhance the potency of vaccine-elicited antibodies and microbicides at mucosal sites of HIV-1 transmission.IMPORTANCE An effective vaccine to prevent transmission of HIV-1 is a primary goal of the scientific and health care communities. Vaccine-elicited antibodies target the viral envelope glycoproteins (Envs) and can potentially inhibit infection. However, the potency of such antibodies is generally low. Single-site mutations in Env can enhance the global sensitivity of HIV-1 to neutralization by antibodies. We found that such a hypersensitivity phenotype can also be induced by agents that destabilize protein structure. Exposure to 0°C or low concentrations of Env-activating ligands gradually guides Env to metastable forms that expose cryptic epitopes and that are highly sensitive to neutralization. Low concentrations of the chaotropic agent urea do not affect native Env but destabilize perturbed states induced by cold or CD4Ms and increase their neutralization. The concept of enhancing antibody sensitivity by chemical agents that affect the structural stability of proteins can be applied to increase the potency of topical microbicides and vaccine-elicited antibodies.
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Qi Q, Wang Q, Chen W, Du L, Dimitrov DS, Lu L, Jiang S. HIV-1 gp41-targeting fusion inhibitory peptides enhance the gp120-targeting protein-mediated inactivation of HIV-1 virions. Emerg Microbes Infect 2017. [PMID: 28634358 PMCID: PMC5520319 DOI: 10.1038/emi.2017.46] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Protein- or peptide-based viral inactivators are being developed as novel antiviral drugs with improved efficacy, pharmacokinetics and toxicity profiles because they actively inactivate cell-free human immunodeficiency virus type 1 (HIV-1) virions before attachment to host cells. By contrast, most clinically used antiviral drugs must penetrate host cells to inhibit viral replication. In this study, we pre-treated HIV-1 particles with a gp120-targeting bispecific multivalent protein, 2Dm2m or 4Dm2m, in the presence or absence of the gp41-targeting HIV-1 fusion inhibitory peptides enfuvirtide (T20), T2635, or sifuvirtide (SFT). HIV-1 virions were separated from the inhibitors using PEG-6000, followed by testing of the residual infectivity of the HIV-1 virions. 2Dm2m and 4Dm2m exhibited significant inactivation activity against all HIV-1 strains tested with EC50 values at the low nanomolar level, whereas none of the gp41-targeting peptides showed inactivation activity at concentrations up to 250 nM. Notably, these three peptides significantly enhanced protein-mediated inactivation against cell-free HIV-1 virions, including HIV-1 laboratory-adapted and primary HIV-1 strains, as well as those resistant to T20 or T2635 and virions released from reactivated latently HIV-1-infected cells. These results indicate that the gp120-targeting bispecific multivalent proteins 2Dm2m and 4Dm2m have potential for further development as HIV-1 inactivator-based antiviral drugs for use in the clinic, either alone or in combination with a gp41-targeting HIV-1 fusion inhibitor such as T20, to treat patients with HIV-1 infection and AIDS.
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Affiliation(s)
- Qianqian Qi
- Key Laboratory of Medical Molecular Virology of Ministries of Education and Health, Shanghai Medical College and Shanghai Public Health Clinical Center, Fudan University, Shanghai 200032, China.,Lindsley F. Kimball Research Institute, New York Blood Center, New York, NY 10065, USA
| | - Qian Wang
- Key Laboratory of Medical Molecular Virology of Ministries of Education and Health, Shanghai Medical College and Shanghai Public Health Clinical Center, Fudan University, Shanghai 200032, China
| | - Weizao Chen
- Protein Interactions Section, Cancer and Inflammation Program, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, MD 21702, USA
| | - Lanying Du
- Lindsley F. Kimball Research Institute, New York Blood Center, New York, NY 10065, USA
| | - Dimiter S Dimitrov
- Protein Interactions Section, Cancer and Inflammation Program, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, MD 21702, USA
| | - Lu Lu
- Key Laboratory of Medical Molecular Virology of Ministries of Education and Health, Shanghai Medical College and Shanghai Public Health Clinical Center, Fudan University, Shanghai 200032, China
| | - Shibo Jiang
- Key Laboratory of Medical Molecular Virology of Ministries of Education and Health, Shanghai Medical College and Shanghai Public Health Clinical Center, Fudan University, Shanghai 200032, China.,Lindsley F. Kimball Research Institute, New York Blood Center, New York, NY 10065, USA
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48
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Falkenhagen A, Joshi S. Further Characterization of the Bifunctional HIV Entry Inhibitor sCD4-FI T45. MOLECULAR THERAPY-NUCLEIC ACIDS 2017. [PMID: 28624214 PMCID: PMC5432676 DOI: 10.1016/j.omtn.2017.04.017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
HIV entry into target cells is a highly sequential and time-sensitive process. In recent years, potent HIV Env-targeting antibodies, such as VRC01, have been identified. However, antibodies bind only to a single epitope, and mutations that confer resistance to antibody-mediated inhibition of HIV entry have been detected. In contrast, HIV cannot escape from binding to soluble CD4 (sCD4) without a fitness disadvantage. sCD4 has the unique ability to induce conformational changes within the HIV envelope glycoproteins (Env) that allow fusion inhibitors to bind. We have previously linked sCD4 to the fusion inhibitor FIT45 (sCD4-FIT45) and examined delivery of the bifunctional entry inhibitor via gene therapy. Here, we extend our studies and analyze the ability of sCD4-FIT45 to inhibit HIV Env-mediated cell fusion and HIV entry of several primary isolates. sCD4-FIT45 inhibited both cell fusion and HIV entry with remarkable antiviral activity. The mean 50% inhibitory concentrations (IC50) for sCD4-FIT45 were <0.2 μg/mL in both assays. Importantly, inhibition by sCD4-FIT45 was more potent than by VRC01, sCD4, or the previously described bifunctional protein sCD4-scFv17b. In contrast to sCD4, sCD4-FIT45 as well as VRC01 and sCD4-scFv17b did not mediate cell fusion between HIV Env+ and CD4−CCR5+ cells. The results presented here provide further evidence for the testing of sCD4-FIT45 and development of bifunctional proteins based on the sCD4-fusion inhibitor architecture.
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Affiliation(s)
- Alexander Falkenhagen
- Department of Laboratory Medicine and Pathobiology, University of Toronto, 150 College Street, Rm. 210, Toronto, ON M5S 3E2, Canada
| | - Sadhna Joshi
- Department of Laboratory Medicine and Pathobiology, University of Toronto, 150 College Street, Rm. 210, Toronto, ON M5S 3E2, Canada; Department of Molecular Genetics, University of Toronto, 150 College Street, Rm. 210, Toronto, ON M5S 3E2, Canada.
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DeLeon O, Hodis H, O’Malley Y, Johnson J, Salimi H, Zhai Y, Winter E, Remec C, Eichelberger N, Van Cleave B, Puliadi R, Harrington RD, Stapleton JT, Haim H. Accurate predictions of population-level changes in sequence and structural properties of HIV-1 Env using a volatility-controlled diffusion model. PLoS Biol 2017; 15:e2001549. [PMID: 28384158 PMCID: PMC5383018 DOI: 10.1371/journal.pbio.2001549] [Citation(s) in RCA: 19] [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: 11/11/2016] [Accepted: 03/06/2017] [Indexed: 01/08/2023] Open
Abstract
The envelope glycoproteins (Envs) of HIV-1 continuously evolve in the host by random mutations and recombination events. The resulting diversity of Env variants circulating in the population and their continuing diversification process limit the efficacy of AIDS vaccines. We examined the historic changes in Env sequence and structural features (measured by integrity of epitopes on the Env trimer) in a geographically defined population in the United States. As expected, many Env features were relatively conserved during the 1980s. From this state, some features diversified whereas others remained conserved across the years. We sought to identify “clues” to predict the observed historic diversification patterns. Comparison of viruses that cocirculate in patients at any given time revealed that each feature of Env (sequence or structural) exists at a defined level of variance. The in-host variance of each feature is highly conserved among individuals but can vary between different HIV-1 clades. We designate this property “volatility” and apply it to model evolution of features as a linear diffusion process that progresses with increasing genetic distance. Volatilities of different features are highly correlated with their divergence in longitudinally monitored patients. Volatilities of features also correlate highly with their population-level diversification. Using volatility indices measured from a small number of patient samples, we accurately predict the population diversity that developed for each feature over the course of 30 years. Amino acid variants that evolved at key antigenic sites are also predicted well. Therefore, small “fluctuations” in feature values measured in isolated patient samples accurately describe their potential for population-level diversification. These tools will likely contribute to the design of population-targeted AIDS vaccines by effectively capturing the diversity of currently circulating strains and addressing properties of variants expected to appear in the future. HIV-1 is the causative agent of the global AIDS pandemic. The envelope glycoproteins (Envs) of HIV-1 constitute a primary target for antibody-based vaccines. However, the diversity of Envs in the population limits the potential efficacy of this approach. Accurate estimates of the range of variants that currently infect patients and those expected to appear in the future will likely contribute to the design of population-targeted immunogens. We found that different properties (features) of Env have different propensities for small “fluctuations” in their values among viruses that infect patients at any given time point. This propensity of each feature for in-host variance, which we designate “volatility”, is conserved among patients. We apply this parameter to model the evolution of features (in patients and population) as a diffusion process driven by their “diffusion coefficients” (volatilities). Using volatilities measured from a few patient samples from the 1980s, we accurately predict properties of viruses that evolved in the population over the course of 30 years. The diffusion-based model described here efficiently captures evolution of phenotypes in biological systems controlled by a dominant random component.
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Affiliation(s)
- Orlando DeLeon
- Department of Microbiology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Hagit Hodis
- Department of Microbiology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Yunxia O’Malley
- Department of Microbiology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Jacklyn Johnson
- Department of Microbiology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Hamid Salimi
- Department of Microbiology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Yinjie Zhai
- Department of Microbiology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Elizabeth Winter
- Department of Microbiology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Claire Remec
- Department of Microbiology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Noah Eichelberger
- Department of Microbiology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Brandon Van Cleave
- Department of Microbiology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Ramya Puliadi
- Department of Microbiology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Robert D. Harrington
- Center for AIDS Research (CFAR) at the University of Washington, Seattle, Washington, United States of America
| | - Jack T. Stapleton
- Department of Microbiology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
- Veterans Affairs Medical Center, Iowa City, Iowa, United States of America
| | - Hillel Haim
- Department of Microbiology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
- * E-mail:
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Harada S, Yoshimura K. Driving HIV-1 into a Vulnerable Corner by Taking Advantage of Viral Adaptation and Evolution. Front Microbiol 2017; 8:390. [PMID: 28360890 PMCID: PMC5352695 DOI: 10.3389/fmicb.2017.00390] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Accepted: 02/24/2017] [Indexed: 12/12/2022] Open
Abstract
Anti-retroviral therapy (ART) is crucial for controlling human immunodeficiency virus type-1 (HIV-1) infection. Recently, progress in identifying and characterizing highly potent broadly neutralizing antibodies has provided valuable templates for HIV-1 therapy and vaccine design. Nevertheless, HIV-1, like many RNA viruses, exhibits genetically diverse populations known as quasispecies. Evolution of quasispecies can occur rapidly in response to selective pressures, such as that exerted by ART and the immune system. Hence, rapid viral evolution leading to drug resistance and/or immune evasion is a significant barrier to the development of effective HIV-1 treatments and vaccines. Here, we describe our recent investigations into evolutionary pressure exerted by anti-retroviral drugs and monoclonal neutralizing antibodies (NAbs) on HIV-1 envelope sequences. We also discuss sensitivities of HIV-1 escape mutants to maraviroc, a CCR5 inhibitor, and HIV-1 sensitized to NAbs by small-molecule CD4-mimetic compounds. These studies help to develop an understanding of viral evolution and escape from both anti-retroviral drugs and the immune system, and also provide fundamental insights into the combined use of NAbs and entry inhibitors. These findings of the adaptation and evolution of HIV in response to drug and immune pressure will inform the development of more effective antiviral therapeutic strategies.
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Affiliation(s)
- Shigeyoshi Harada
- AIDS Research Center, National Institute of Infectious Diseases Tokyo, Japan
| | - Kazuhisa Yoshimura
- AIDS Research Center, National Institute of Infectious Diseases Tokyo, Japan
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