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Bennett AL, Edwards R, Kosheleva I, Saunders C, Bililign Y, Williams A, Bubphamala P, Manosouri K, Anasti K, Saunders KO, Alam SM, Haynes BF, Acharya P, Henderson R. Microsecond dynamics control the HIV-1 Envelope conformation. SCIENCE ADVANCES 2024; 10:eadj0396. [PMID: 38306419 PMCID: PMC10836732 DOI: 10.1126/sciadv.adj0396] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Accepted: 01/03/2024] [Indexed: 02/04/2024]
Abstract
The HIV-1 Envelope (Env) glycoprotein facilitates host cell fusion through a complex series of receptor-induced structural changes. Although remarkable progress has been made in understanding the structures of various Env conformations, microsecond timescale dynamics have not been studied experimentally. Here, we used time-resolved, temperature-jump small-angle x-ray scattering to monitor structural rearrangements in an HIV-1 Env SOSIP ectodomain construct with microsecond precision. In two distinct Env variants, we detected a transition that correlated with known Env structure rearrangements with a time constant in the hundreds of microseconds range. A previously unknown structural transition was also observed, which occurred with a time constant below 10 μs, and involved an order-to-disorder transition in the trimer apex. Using this information, we engineered an Env SOSIP construct that locks the trimer in the prefusion closed state by connecting adjacent protomers via disulfides. Our findings show that the microsecond timescale structural dynamics play an essential role in controlling the Env conformation with impacts on vaccine design.
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Affiliation(s)
- Ashley L. Bennett
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC 27710, USA
| | - Robert Edwards
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC 27710, USA
| | - Irina Kosheleva
- BioCARS, Center for Advanced Radiation Sources, The University of Chicago, 9700 South Cass Ave, Bld 434B, Lemont, IL 60439, USA
| | - Carrie Saunders
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC 27710, USA
| | - Yishak Bililign
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC 27710, USA
| | - Ashliegh Williams
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC 27710, USA
| | - Pimthada Bubphamala
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC 27710, USA
| | - Katayoun Manosouri
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC 27710, USA
| | - Kara Anasti
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC 27710, USA
| | - Kevin O. Saunders
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC 27710, USA
- Department of Surgery, Duke University Medical Center, Durham, NC 27710, USA
- Department of Integrative Immunobiology, Duke University Medical Center, Durham, NC 27710, USA
| | - S. Munir Alam
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC 27710, USA
- Department of Medicine, Duke University Medical Center, Durham, NC 27710, USA
- Department of Pathology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Barton F. Haynes
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC 27710, USA
- Department of Medicine, Duke University Medical Center, Durham, NC 27710, USA
- Department of Integrative Immunobiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Priyamvada Acharya
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC 27710, USA
- BioCARS, Center for Advanced Radiation Sources, The University of Chicago, 9700 South Cass Ave, Bld 434B, Lemont, IL 60439, USA
- Department of Biochemistry, Duke University, Durham, NC 27710, USA
| | - Rory Henderson
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC 27710, USA
- Department of Medicine, Duke University Medical Center, Durham, NC 27710, USA
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2
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Xue S, Xu W, Wang L, Xu L, Calcul L, Teng P, Lu L, Jiang S, Cai J. Rational Design of Sulfonyl-γ-AApeptides as Highly Potent HIV-1 Fusion Inhibitors with Broad-Spectrum Activity. J Med Chem 2023; 66:13319-13331. [PMID: 37706450 DOI: 10.1021/acs.jmedchem.3c01412] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/15/2023]
Abstract
The HIV-1 epidemic has significant social and economic implications for public health. Developing new antivirus drugs to eradicate drug resistance is still urgently needed. Herein, we demonstrated that sulfonyl-γ-AApeptides could be designed to mimic MTSC22EK, one potent HIV fusion inhibitor derived from CHR. The best two sequences revealed comparable activity to MTSC22EK in an authentic HIV-1 infection assay and exhibited broad-spectrum anti-HIV-1 activity to many HIV-1 clinical isolates. Furthermore, sulfonyl-γ-AApeptides show remarkable resistance to proteolysis and favorable permeability in PAMPA-GIT and PAMPA-BBB assays, suggesting that both sequences could control HIV-1 within the central nervous system and possess promising oral bioavailability. Mechanistic investigations suggest that these sulfonyl-γ-AApeptides function by mimicking the CHR of gp41 and tightly bind with NHR, thereby inhibiting the formation of the 6-HB structure necessary for HIV-1 fusion. Overall, our results suggest that sulfonyl-γ-AApeptides represent a new generation of anti-HIV-1 fusion inhibitors. Moreover, this design strategy could be adopted to modulate many of the PPIs.
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Affiliation(s)
- Songyi Xue
- Department of Chemistry, University of South Florida, 4202 E. Fowler Avenue, Tampa, Florida 33620, United States
| | - Wei Xu
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences, Shanghai Frontiers Science Center of Pathogenic Microbes and Infection, Shanghai Institute of Infectious Disease and Biosecurity, Fudan University, Shanghai 200032, China
| | - Lei Wang
- Department of Chemistry, University of South Florida, 4202 E. Fowler Avenue, Tampa, Florida 33620, United States
| | - Ling Xu
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences, Shanghai Frontiers Science Center of Pathogenic Microbes and Infection, Shanghai Institute of Infectious Disease and Biosecurity, Fudan University, Shanghai 200032, China
| | - Laurent Calcul
- Department of Chemistry, University of South Florida, 4202 E. Fowler Avenue, Tampa, Florida 33620, United States
| | - Peng Teng
- Department of Chemistry, University of South Florida, 4202 E. Fowler Avenue, Tampa, Florida 33620, United States
| | - Lu Lu
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences, Shanghai Frontiers Science Center of Pathogenic Microbes and Infection, Shanghai Institute of Infectious Disease and Biosecurity, Fudan University, Shanghai 200032, China
| | - Shibo Jiang
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences, Shanghai Frontiers Science Center of Pathogenic Microbes and Infection, Shanghai Institute of Infectious Disease and Biosecurity, Fudan University, Shanghai 200032, China
| | - Jianfeng Cai
- Department of Chemistry, University of South Florida, 4202 E. Fowler Avenue, Tampa, Florida 33620, United States
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3
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Bennett AL, Edwards RJ, Kosheleva I, Saunders C, Bililign Y, Williams A, Manosouri K, Saunders KO, Haynes BF, Acharya P, Henderson R. Microsecond dynamics control the HIV-1 envelope conformation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.17.541130. [PMID: 37292605 PMCID: PMC10245784 DOI: 10.1101/2023.05.17.541130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The HIV-1 Envelope (Env) glycoprotein facilitates host cell fusion through a complex series of receptor-induced structural changes. Although significant progress has been made in understanding the structures of various Env conformations and transition intermediates that occur within the millisecond timescale, faster transitions in the microsecond timescale have not yet been observed. In this study, we employed time-resolved, temperature-jump small angle X-ray scattering to monitor structural rearrangements in an HIV-1 Env ectodomain construct with microsecond precision. We detected a transition correlated with Env opening that occurs in the hundreds of microseconds range and another more rapid transition that preceded this opening. Model fitting indicated that the early rapid transition involved an order-to-disorder transition in the trimer apex loop contacts, suggesting that conventional conformation-locking design strategies that target the allosteric machinery may be ineffective in preventing this movement. Utilizing this information, we engineered an envelope that locks the apex loop contacts to the adjacent protomer. This modification resulted in significant angle-of-approach shifts in the interaction of a neutralizing antibody. Our findings imply that blocking the intermediate state could be crucial for inducing antibodies with the appropriate bound state orientation through vaccination.
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Affiliation(s)
- Ashley L Bennett
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC 27710, USA
| | - R J Edwards
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC 27710, USA
| | - Irina Kosheleva
- BioCARS, Center for Advanced Radiation Sources, The University of Chicago, 9700 South Cass Ave, Bld 434B, Lemont, IL 60439, USA
| | - Carrie Saunders
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC 27710, USA
| | - Yishak Bililign
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC 27710, USA
| | - Ashliegh Williams
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC 27710, USA
| | - Katayoun Manosouri
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC 27710, USA
| | - Kevin O Saunders
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC 27710, USA
- Department of Surgery, Duke University Medical Center, Durham, NC 27710, USA
| | - Barton F Haynes
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC 27710, USA
- Department of Immunology, Duke University Medical Center, Durham, NC 27710, USA
- Department of Biochemistry, Duke University, Durham, NC 27710, USA
| | - Priyamvada Acharya
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC 27710, USA
- Department of Surgery, Duke University Medical Center, Durham, NC 27710, USA
- Department of Biochemistry, Duke University, Durham, NC 27710, USA
| | - Rory Henderson
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC 27710, USA
- Department of Medicine, Duke University Medical Center, Durham, NC 27710, USA
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4
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Negi G, Sharma A, Dey M, Dhanawat G, Parveen N. Membrane attachment and fusion of HIV-1, influenza A, and SARS-CoV-2: resolving the mechanisms with biophysical methods. Biophys Rev 2022; 14:1109-1140. [PMID: 36249860 PMCID: PMC9552142 DOI: 10.1007/s12551-022-00999-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Accepted: 09/16/2022] [Indexed: 10/31/2022] Open
Abstract
Attachment to and fusion with cell membranes are two major steps in the replication cycle of many human viruses. We focus on these steps for three enveloped viruses, i.e., HIV-1, IAVs, and SARS-CoV-2. Viral spike proteins drive the membrane attachment and fusion of these viruses. Dynamic interactions between the spike proteins and membrane receptors trigger their specific attachment to the plasma membrane of host cells. A single virion on cell membranes can engage in binding with multiple receptors of the same or different types. Such dynamic and multivalent binding of these viruses result in an optimal attachment strength which in turn leads to their cellular entry and membrane fusion. The latter process is driven by conformational changes of the spike proteins which are also class I fusion proteins, providing the energetics of membrane tethering, bending, and fusion. These viruses exploit cellular and membrane factors in regulating the conformation changes and membrane processes. Herein, we describe the major structural and functional features of spike proteins of the enveloped viruses including highlights on their structural dynamics. The review delves into some of the case studies in the literature discussing the findings on multivalent binding, membrane hemifusion, and fusion of these viruses. The focus is on applications of biophysical tools with an emphasis on single-particle methods for evaluating mechanisms of these processes at the molecular and cellular levels.
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Affiliation(s)
- Geetanjali Negi
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, India
| | - Anurag Sharma
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, India
| | - Manorama Dey
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, India
| | - Garvita Dhanawat
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, India
| | - Nagma Parveen
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, India
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5
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Comparing methods for immobilizing HIV-1 SOSIPs in ELISAs that evaluate antibody binding. Sci Rep 2022; 12:11172. [PMID: 35778473 PMCID: PMC9247892 DOI: 10.1038/s41598-022-15506-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Accepted: 06/24/2022] [Indexed: 11/09/2022] Open
Abstract
Enzyme-linked immunosorbent assays (ELISAs) are used to evaluate binding of broadly neutralizing antibodies (bNAbs) and polyclonal sera to native-like HIV-1 Env SOSIPs. Methods for immobilizing SOSIPs on plates differ, which can lead to variable or, in some cases, misleading results. Three methods used to immobilize SOSIPs were compared to determine how antigen immobilization methods affect Env conformation and ELISA results. HIV-1 SOSIPs were directly coated on polystyrene plates, captured by a monoclonal antibody against a C-terminal affinity tag, or randomly biotinylated and coated on a streptavidin plate. Binding of bNAbs with known epitopes were compared for each immobilization method. Binding of bNAbs targeting the V1V2, V3, CD4 binding site, and gp120/gp41 interface was comparable for all antigen immobilization methods. However, directly coated HIV-1 SOSIP ELISAs showed detectable binding of 17b, a CD4-induced antibody that binds a V3 epitope that is concealed on closed prefusion Env trimers in the absence of added CD4, whereas antibody-immobilized and randomly biotinylated Env-coated ELISAs did not show detectable binding of 17b in the absence of CD4. We conclude direct coating of HIV-1 SOSIPs on ELISA plates can result in exposure of CD4-induced antibody epitopes, suggesting disruption of Env structure and exposure of epitopes that are hidden in the closed, prefusion trimer.
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6
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Batishchev OV. Physico-Chemical Mechanisms of the Functioning of Membrane-Active Proteins of Enveloped Viruses. BIOCHEMISTRY (MOSCOW) SUPPLEMENT. SERIES A, MEMBRANE AND CELL BIOLOGY 2022; 16:247-260. [PMCID: PMC9734521 DOI: 10.1134/s1990747822050038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Revised: 06/01/2022] [Accepted: 06/02/2022] [Indexed: 12/14/2022]
Abstract
Over the past few years, the attention of the whole world has been riveted to the emergence of new dangerous strains of viruses, among which a special place is occupied by coronaviruses that have overcome the interspecies barrier in the past 20 years: SARS viruses (SARS), Middle East respiratory syndrome (MERS), as well as a new coronavirus infection (SARS-CoV-2), which caused the largest pandemic since the Spanish flu in 1918. Coronaviruses are members of a class of enveloped viruses that have a lipoprotein envelope. This class also includes such serious pathogens as human immunodeficiency virus (HIV), hepatitis, Ebola virus, influenza, etc. Despite significant differences in the clinical picture of the course of disease caused by enveloped viruses, they themselves have a number of characteristic features, which determine their commonality. Regardless of the way of penetration into the cell—by endocytosis or direct fusion with the cell membrane—enveloped viruses are characterized by the following stages of interaction with the target cell: binding to receptors on the cell surface, interaction of the surface glycoproteins of the virus with the membrane structures of the infected cell, fusion of the lipid envelope of the virion with plasma or endosomal membrane, destruction of the protein capsid and its dissociation from the viral nucleoprotein. Subsequently, within the infected cell, the newly synthesized viral proteins must self-assemble on various membrane structures to form a progeny virion. Thus, both the initial stages of viral infection and the assembly and release of new viral particles are associated with the activity of viral proteins in relation to the cell membrane and its organelles. This review is devoted to the analysis of physicochemical mechanisms of functioning of the main structural proteins of a number of enveloped viruses in order to identify possible strategies for the membrane activity of such proteins at various stages of viral infection of the cell.
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Affiliation(s)
- O. V. Batishchev
- Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, 119071 Moscow, Russia
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7
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Evolution of antibodies to native trimeric envelope and their Fc dependent functions in untreated and treated primary HIV infection. J Virol 2021; 95:e0162521. [PMID: 34586863 DOI: 10.1128/jvi.01625-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
People living with HIV (PLWH) develop both anti-Envelope-specific antibodies, which bind the closed trimeric HIV Envelope present on infected cells and anti-gp120-specific antibodies, which bind gp120 monomers shed by infected cells and taken up by CD4 on uninfected bystander cells. Both antibodies have an Fc portion that binds to Fc Receptors on several types of innate immune cells and stimulates them to develop anti-viral functions. Among these Fc dependent functions (FcDFs) are antibody dependent (AD) cellular cytotoxicity (ADCC), AD cellular trogocytosis (ADCT) and AD phagocytosis (ADCP). Here, we assessed the evolution of total immunoglobulin G (IgG), anti-gp120 and anti-Envelope IgG antibodies and their FcDFs in plasma samples from anti-retroviral therapy (ART) naïve subjects during early HIV infection (28-194 days post infection [DPI]). We found that both the concentrations and FcDFs of anti-gp120 and anti-Envelope antibodies increased with time in ART-naïve PLWH. Although generated concurrently, anti-gp120-specific antibodies were 20.7-fold more abundant than anti-Envelpe-specific antibodies, both specificities being strongly correlated with each other and FcDFs. Among the FcDFs, only ADCP activity was inversely correlated with concurrent viral load. PLWH who started ART >90 DPI showed higher anti-Envelope-specific antibody levels, ADCT and ADCP activities than those starting ART <90 DPI. However, in longitudinally collected samples, ART initiation at >90 DPI was accompanied by a faster decline in anti-Envelope-specific antibody levels, which did not translate to a faster decline in FcDFs compared to those starting ART <90 DPI. IMPORTANCE Closed conformation Envelope is expressed on the surface of HIV-infected cells. Antibodies targeting this conformation and that support FcDFs have the potential to control HIV. This study tracks the timing of the appearance and evolution of antibodies to closed conformation Envelope, whose concentration increases over the first 6 mos of infection. Antiretroviral therapy (ART) initiation blunts further increases in the concentration of these antibodies and their and FcDFs. However, antibodies to open conformation Envelope also increase with DPI until ART initiation. These antibodies target uninfected bystander cells, which may contribute to loss of uninfected CD4 cells and pathogenicity. This manuscript presents, for the first time, the evolution of antibodies to closed conformation Envelope and their fate on-ART. This information may be useful in making decisions on the timing of ART initiation in early HIV infection.
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Fiorino S, Tateo F, Biase DD, Gallo CG, Orlandi PE, Corazza I, Budriesi R, Micucci M, Visani M, Loggi E, Hong W, Pica R, Lari F, Zippi M. SARS-CoV-2: lessons from both the history of medicine and from the biological behavior of other well-known viruses. Future Microbiol 2021; 16:1105-1133. [PMID: 34468163 PMCID: PMC8412036 DOI: 10.2217/fmb-2021-0064] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Accepted: 07/22/2021] [Indexed: 02/07/2023] Open
Abstract
SARS-CoV-2 is the etiological agent of the current pandemic worldwide and its associated disease COVID-19. In this review, we have analyzed SARS-CoV-2 characteristics and those ones of other well-known RNA viruses viz. HIV, HCV and Influenza viruses, collecting their historical data, clinical manifestations and pathogenetic mechanisms. The aim of the work is obtaining useful insights and lessons for a better understanding of SARS-CoV-2. These pathogens present a distinct mode of transmission, as SARS-CoV-2 and Influenza viruses are airborne, whereas HIV and HCV are bloodborne. However, these viruses exhibit some potential similar clinical manifestations and pathogenetic mechanisms and their understanding may contribute to establishing preventive measures and new therapies against SARS-CoV-2.
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Affiliation(s)
- Sirio Fiorino
- Internal Medicine Unit, Budrio Hospital, Budrio (Bologna), Azienda USL, Bologna, 40054, Italy
| | - Fabio Tateo
- Institute of Geosciences & Earth Resources, CNR, c/o Department of Geosciences, Padova University, 35127, Italy
| | - Dario De Biase
- Department of Pharmacy & Biotechnology, University of Bologna, Bologna, 40126, Italy
| | - Claudio G Gallo
- Fisiolaserterapico Emiliano, Castel San Pietro Terme, Bologna, 40024, Italy
| | | | - Ivan Corazza
- Department of Experimental, Diagnostic & Specialty Medicine, University of Bologna, Bologna, 40126, Italy
| | - Roberta Budriesi
- Department of Pharmacy & Biotechnology, Alma Mater Studiorum-University of Bologna, Bologna, 40126, Italy
| | - Matteo Micucci
- Department of Pharmacy & Biotechnology, Alma Mater Studiorum-University of Bologna, Bologna, 40126, Italy
| | - Michela Visani
- Department of Pharmacy & Biotechnology, University of Bologna, Bologna, 40126, Italy
| | - Elisabetta Loggi
- Hepatology Unit, Department of Medical & Surgical Sciences, University of Bologna, Bologna, 40126, Italy
| | - Wandong Hong
- Department of Gastroenterology & Hepatology, First Affiliated Hospital of Wenzhou Medical University, Wenzhou City, Zhejiang, 325035, PR China
| | - Roberta Pica
- Unit of Gastroenterology & Digestive Endoscopy, Sandro Pertini Hospital, Rome, 00157, Italy
| | - Federico Lari
- Internal Medicine Unit, Budrio Hospital, Budrio (Bologna), Azienda USL, Bologna, 40054, Italy
| | - Maddalena Zippi
- Unit of Gastroenterology & Digestive Endoscopy, Sandro Pertini Hospital, Rome, 00157, Italy
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9
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Abstract
The host immune system is highly compromised in case of viral infections and relapses are very common. The capacity of the virus to destroy the host cell by liberating its own DNA or RNA and replicating inside the host cell poses challenges in the development of antiviral therapeutics. In recent years, many new technologies have been explored for diagnosis, prevention, and treatment of viral infections. Nanotechnology has emerged as one of the most promising technologies on account of its ability to deal with viral diseases in an effective manner, addressing the limitations of traditional antiviral medicines. It has not only helped us to overcome problems related to solubility and toxicity of drugs, but also imparted unique properties to drugs, which in turn has increased their potency and selectivity toward viral cells against the host cells. The initial part of the paper focuses on some important proteins of influenza, Ebola, HIV, herpes, Zika, dengue, and corona virus and those of the host cells important for their entry and replication into the host cells. This is followed by different types of nanomaterials which have served as delivery vehicles for the antiviral drugs. It includes various lipid-based, polymer-based, lipid-polymer hybrid-based, carbon-based, inorganic metal-based, surface-modified, and stimuli-sensitive nanomaterials and their application in antiviral therapeutics. The authors also highlight newer promising treatment approaches like nanotraps, nanorobots, nanobubbles, nanofibers, nanodiamonds, nanovaccines, and mathematical modeling for the future. The paper has been updated with the recent developments in nanotechnology-based approaches in view of the ongoing pandemic of COVID-19.Graphical abstract.
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Affiliation(s)
- Malobika Chakravarty
- Shobhaben Pratapbhai Patel School of Pharmacy and Technology Management, SVKM's NMIMS, V. L. Mehta Road, Vile Parle (W), Mumbai, 400056, India
| | - Amisha Vora
- Shobhaben Pratapbhai Patel School of Pharmacy and Technology Management, SVKM's NMIMS, V. L. Mehta Road, Vile Parle (W), Mumbai, 400056, India.
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10
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Narayanan KK, Procko E. Deep Mutational Scanning of Viral Glycoproteins and Their Host Receptors. Front Mol Biosci 2021; 8:636660. [PMID: 33898517 PMCID: PMC8062978 DOI: 10.3389/fmolb.2021.636660] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Accepted: 03/18/2021] [Indexed: 11/17/2022] Open
Abstract
Deep mutational scanning or deep mutagenesis is a powerful tool for understanding the sequence diversity available to viruses for adaptation in a laboratory setting. It generally involves tracking an in vitro selection of protein sequence variants with deep sequencing to map mutational effects based on changes in sequence abundance. Coupled with any of a number of selection strategies, deep mutagenesis can explore the mutational diversity available to viral glycoproteins, which mediate critical roles in cell entry and are exposed to the humoral arm of the host immune response. Mutational landscapes of viral glycoproteins for host cell attachment and membrane fusion reveal extensive epistasis and potential escape mutations to neutralizing antibodies or other therapeutics, as well as aiding in the design of optimized immunogens for eliciting broadly protective immunity. While less explored, deep mutational scans of host receptors further assist in understanding virus-host protein interactions. Critical residues on the host receptors for engaging with viral spikes are readily identified and may help with structural modeling. Furthermore, mutations may be found for engineering soluble decoy receptors as neutralizing agents that specifically bind viral targets with tight affinity and limited potential for viral escape. By untangling the complexities of how sequence contributes to viral glycoprotein and host receptor interactions, deep mutational scanning is impacting ideas and strategies at multiple levels for combatting circulating and emergent virus strains.
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Affiliation(s)
| | - Erik Procko
- Department of Biochemistry and Cancer Center at Illinois, University of Illinois, Urbana, IL, United States
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11
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Aisenbrey C, Rifi O, Bechinger B. Structure, membrane topology and influence of cholesterol of the membrane proximal region: transmembrane helical anchor sequence of gp41 from HIV. Sci Rep 2020; 10:22278. [PMID: 33335248 PMCID: PMC7746737 DOI: 10.1038/s41598-020-79327-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Accepted: 11/30/2020] [Indexed: 11/13/2022] Open
Abstract
During the first steps of HIV infection the Env subunit gp41 is thought to establish contact between the membranes and to be the main driver of fusion. Here we investigated in liquid crystalline membranes the structure and cholesterol recognition of constructs made of a gp41 external region carrying a cholesterol recognition amino acid consensus (CRAC) motif and a hydrophobic membrane anchoring sequence. CD- und ATR-FTIR spectroscopies indicate that the constructs adopt a high degree of helical secondary structure in membrane environments. Furthermore, 15N and 2H solid-state NMR spectra of gp41 polypeptides reconstituted into uniaxially oriented bilayers agree with the CRAC domain being an extension of the transmembrane helix. Upon addition of cholesterol the CRAC NMR spectra remain largely unaffected when being associated with the native gp41 transmembrane sequence but its topology changes when anchored in the membrane by a hydrophobic model sequence. The 2H solid-state NMR spectra of deuterated cholesterol are indicative of a stronger influence of the model sequence on this lipid when compared to the native gp41 sequence. These observations are suggestive of a strong coupling between the transmembrane and the membrane proximal region of gp41 possibly enforced by oligomerization of the transmembrane helical region.
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Affiliation(s)
- Christopher Aisenbrey
- Institut de chimie de Strasbourg, UMR7177, University of Strasbourg/CNRS, 4, Rue Blaise Pascal, 67070, Strasbourg, France
| | - Omar Rifi
- Institut de chimie de Strasbourg, UMR7177, University of Strasbourg/CNRS, 4, Rue Blaise Pascal, 67070, Strasbourg, France
| | - Burkhard Bechinger
- Institut de chimie de Strasbourg, UMR7177, University of Strasbourg/CNRS, 4, Rue Blaise Pascal, 67070, Strasbourg, France.
- Institut Universitaire de France, Paris, France.
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12
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Nechipurenko YD, Anashkina AA, Matveeva OV. Change of Antigenic Determinants of SARS-CoV-2 Virus S-Protein as a Possible Cause of Antibody-Dependent Enhancement of Virus Infection and Cytokine Storm. Biophysics (Nagoya-shi) 2020; 65:703-709. [PMID: 33100352 PMCID: PMC7569100 DOI: 10.1134/s0006350920040119] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 05/28/2020] [Accepted: 06/05/2020] [Indexed: 01/08/2023] Open
Abstract
A hypothesis is proposed that the cytokine storm syndrome, which complicates COVID-19 in some patients, is a consequence of antibody-dependent enhancement of virus infection, which is in turn happens due to a change in dominant antigenic determinants of SARS-CoV-2 S-protein. The antibody-dependent enhancement of virus infection is a phenomenon in which virus-specific antibodies that are not neutralizing enhance the entry of infectious virus into immune cells causing their death. Antibody-dependent enhancement has been reported for different coronaviruses. This phenomenon happens due to a decrease in the binding strength of neutralizing antibodies to the virus, which converts these antibodies into suboptimal-not neutralizing ones. According to our hypothesis, such a decrease in affinity may be associated with a change in the conformation of the viral S-protein. We believe that this conformational change is the major factor in the switching of antibodies affinity, which triggers antibody-dependent enhancement. However, other factors that contribute to antigen drift and antigenic determinant changes may also play a role.
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Affiliation(s)
- Yu. D. Nechipurenko
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 119991 Moscow, Russia
| | - A. A. Anashkina
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 119991 Moscow, Russia
| | - O. V. Matveeva
- Sendai Viralytics LLC, 01720 Acton, MA USA
- Biopolymer Design LLC, 01721 Acton, MA USA
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13
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Akimov SA, Kondrashov OV, Zimmerberg J, Batishchev OV. Ectodomain Pulling Combines with Fusion Peptide Inserting to Provide Cooperative Fusion for Influenza Virus and HIV. Int J Mol Sci 2020; 21:ijms21155411. [PMID: 32751407 PMCID: PMC7432320 DOI: 10.3390/ijms21155411] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 07/24/2020] [Accepted: 07/28/2020] [Indexed: 12/18/2022] Open
Abstract
Enveloped viruses include the most dangerous human and animal pathogens, in particular coronavirus, influenza virus, and human immunodeficiency virus (HIV). For these viruses, receptor binding and entry are accomplished by a single viral envelope protein (termed the fusion protein), the structural changes of which trigger the remodeling and merger of the viral and target cellular membranes. The number of fusion proteins required for fusion activity is still under debate, and several studies report this value to range from 1 to 9 for type I fusion proteins. Here, we consider the earliest stage of viral fusion based on the continuum theory of membrane elasticity. We demonstrate that membrane deformations induced by the oblique insertion of amphipathic fusion peptides mediate the lateral interaction of these peptides and drive them to form into a symmetric fusion rosette. The pulling force produced by the structural rearrangements of the fusion protein ectodomains gives additional torque, which deforms the membrane and additionally stabilizes the symmetric fusion rosette, thus allowing a reduction in the number of fusion peptides needed for fusion. These findings can resolve the large range of published cooperativity indices for HIV, influenza, and other type I fusion proteins.
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Affiliation(s)
- Sergey A. Akimov
- Laboratory of Bioelectrochemistry, A.N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, 31/4 Leninskiy Prospekt, 119071 Moscow, Russia; (O.V.K.); (O.V.B.)
- Correspondence: ; Tel.: +7-495-955-4776
| | - Oleg V. Kondrashov
- Laboratory of Bioelectrochemistry, A.N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, 31/4 Leninskiy Prospekt, 119071 Moscow, Russia; (O.V.K.); (O.V.B.)
| | - Joshua Zimmerberg
- Section on Integrative Biophysics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA;
| | - Oleg V. Batishchev
- Laboratory of Bioelectrochemistry, A.N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, 31/4 Leninskiy Prospekt, 119071 Moscow, Russia; (O.V.K.); (O.V.B.)
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14
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Structure, interactions and membrane topology of HIV gp41 ectodomain sequences. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1862:183274. [DOI: 10.1016/j.bbamem.2020.183274] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Revised: 03/06/2020] [Accepted: 03/10/2020] [Indexed: 11/21/2022]
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15
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de Carvalho Lima EN, Lima RSA, Arif MS, Piqueira JRC, Diaz RS. Evolutive Temporal Footprint of an HIV-1 Envelope Protein in an Epidemiologically Linked Cluster. Open AIDS J 2020. [DOI: 10.2174/1874613602014010041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Background:
The C2V3C3 region of gp 120, encoded by the HIV-1 envelope gene (env), is an important antigenic target, a key determinant for viral evolution and essential for determining epitopes for vaccines.
Methods:
The relationships among genetic sequence diversity, selective pressure, constraints on HIV-1 envelope protein were explored and also correlated this analysis with information entropy; hypermutation; HIV tropism; CD4+ T cell counts or HIV viral load. A total of 179 HIV-1 C2V3C3 sequences derived from cell-free plasma were used, determined from serial samples, in four epidemiologically linked individuals (one infected blood donor, two transfusion recipients and a sexual partner infected by one of the recipients) over a maximum period of 8 years. This study is important because it considers the analysis of patterns in genomic sequences, without drugs and over time.
Results:
A temporal relationship among information entropy, hypermutation, tropism switch, viral load, and CD4+ T cell count was determined. Changes in information entropy were time-dependent, and an increase in entropy was observed in the C2V3C3 region at amino acids G313 and F317-I320 (related to the GPGR-motif and coreceptor tropism), and at amino acids A281 in C2 and A346 in C3, related to immune escape.
Conclusion:
The increase of information entropy over time was correlated with hypermutation and the emergence of nonR5- strains, which are both associated with more variable genomes.
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16
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Murphy RE, Saad JS. The Interplay between HIV-1 Gag Binding to the Plasma Membrane and Env Incorporation. Viruses 2020; 12:E548. [PMID: 32429351 PMCID: PMC7291237 DOI: 10.3390/v12050548] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 05/14/2020] [Accepted: 05/14/2020] [Indexed: 12/21/2022] Open
Abstract
Advancement in drug therapies and patient care have drastically improved the mortality rates of HIV-1 infected individuals. Many of these therapies were developed or improved upon by using structure-based techniques, which underscore the importance of understanding essential mechanisms in the replication cycle of HIV-1 at the structural level. One such process which remains poorly understood is the incorporation of the envelope glycoprotein (Env) into budding virus particles. Assembly of HIV particles is initiated by targeting of the Gag polyproteins to the inner leaflet of the plasma membrane (PM), a process mediated by the N-terminally myristoylated matrix (MA) domain and phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2). There is strong evidence that formation of the Gag lattice on the PM is a prerequisite for the incorporation of Env into budding particles. It is also suggested that Env incorporation is mediated by an interaction between its cytoplasmic tail (gp41CT) and the MA domain of Gag. In this review, we highlight the latest developments and current efforts to understand the interplay between gp41CT, MA, and the membrane during assembly. Elucidation of the molecular determinants of Gag-Env-membrane interactions may help in the development of new antiviral therapeutic agents that inhibit particle assembly, Env incorporation and ultimately virus production.
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Affiliation(s)
| | - Jamil S. Saad
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA;
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17
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Koehler M, Delguste M, Sieben C, Gillet L, Alsteens D. Initial Step of Virus Entry: Virion Binding to Cell-Surface Glycans. Annu Rev Virol 2020; 7:143-165. [PMID: 32396772 DOI: 10.1146/annurev-virology-122019-070025] [Citation(s) in RCA: 76] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Virus infection is an intricate process that requires the concerted action of both viral and host cell components. Entry of viruses into cells is initiated by interactions between viral proteins and cell-surface receptors. Various cell-surface glycans function as initial, usually low-affinity attachment factors, providing a first anchor of the virus to the cell surface, and further facilitate high-affinity binding to virus-specific cell-surface receptors, while other glycans function as specific entry receptors themselves. It is now possible to rapidly identify specific glycan receptors using different techniques, define atomic-level structures of virus-glycan complexes, and study these interactions at the single-virion level. This review provides a detailed overview of the role of glycans in viral infection and highlights experimental approaches to study virus-glycan binding along with specific examples. In particular, we highlight the development of the atomic force microscope to investigate interactions with glycans at the single-virion level directly on living mammalian cells, which offers new perspectives to better understand virus-glycan interactions in physiologically relevant conditions.
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Affiliation(s)
- Melanie Koehler
- Louvain Institute of Biomolecular Science and Technology, Université Catholique de Louvain, 1348 Louvain-la-Neuve, Belgium;
| | - Martin Delguste
- Louvain Institute of Biomolecular Science and Technology, Université Catholique de Louvain, 1348 Louvain-la-Neuve, Belgium;
| | - Christian Sieben
- Institute of Physics, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Laurent Gillet
- Immunology-Vaccinology Laboratory, Department of Infectious and Parasitic Diseases, Fundamental and Applied Research for Animals and Health center (FARAH), University of Liège, 4000 Liège, Belgium
| | - David Alsteens
- Louvain Institute of Biomolecular Science and Technology, Université Catholique de Louvain, 1348 Louvain-la-Neuve, Belgium; .,Walloon Excellence in Life sciences and Biotechnology (WELBIO), 1300 Wavre, Belgium
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18
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Antibody-Dependent Cellular Cytotoxicity-Competent Antibodies against HIV-1-Infected Cells in Plasma from HIV-Infected Subjects. mBio 2019; 10:mBio.02690-19. [PMID: 31848282 PMCID: PMC6918083 DOI: 10.1128/mbio.02690-19] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Measuring Envelope (Env)-specific antibody (Ab)-dependent cellular cytotoxicity (ADCC)-competent Abs in HIV+ plasma is challenging because Env displays distinctive epitopes when present in a native closed trimeric conformation on infected cells or in a CD4-bound conformation on uninfected bystander cells. We developed an ADCC model which distinguishes Env-specific ADCC-competent Abs based on their capacity to eliminate infected, bystander, or Env rgp120-coated cells as a surrogate for shed gp120 on bystander cells. A panel of monoclonal Abs (MAbs), used to opsonize these target cells, showed that infected cells were preferentially recognized/eliminated by MAbs to CD4 binding site, V3 loop, and viral spike epitopes whereas bystander/coated cells were preferentially recognized/eliminated by Abs to CD4-induced (CD4i) epitopes. In HIV-positive (HIV+) plasma, Env-specific Abs recognized and supported ADCC of infected cells, though a majority were directed toward CD4i epitopes on bystander cells. For ADCC activity to be effective in HIV control, ADCC-competent Abs need to target genuinely infected cells.IMPORTANCE HIV Env-specific nonneutralizing Abs (NnAbs) able to mediate ADCC have been implicated in protection from HIV infection. However, Env-specific NnAbs have the capacity to support ADCC of both HIV-infected and HIV-uninfected bystander cells, potentially leading to misinterpretations when the assay used to measure ADCC does not distinguish between the two target cell types present in HIV cultures. Using a novel ADCC assay, which simultaneously quantifies the killing activity of Env-specific Abs on both infected and uninfected bystander cells, we observed that only a minority of Env-specific Abs in HIV+ plasma mediated ADCC of genuinely HIV-infected cells displaying Env in its native closed conformation. This assay can be used for the development of vaccine strategies aimed at eliciting Env-specific Ab responses capable of controlling HIV infection.
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19
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Collier DA, Monit C, Gupta RK. The Impact of HIV-1 Drug Escape on the Global Treatment Landscape. Cell Host Microbe 2019; 26:48-60. [PMID: 31295424 DOI: 10.1016/j.chom.2019.06.010] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The rising prevalence of HIV drug resistance (HIVDR) could threaten gains made in combating the HIV epidemic and compromise the 90-90-90 target proposed by United Nations Programme on HIV/AIDS (UNAIDS) to have achieved virological suppression in 90% of all persons receiving antiretroviral therapy (ART) by the year 2020. HIVDR has implications for the persistence of HIV, the selection of current and future ART drug regimens, and strategies of vaccine and cure development. Focusing on drug classes that are in clinical use, this Review critically summarizes what is known about the mechanisms the virus utilizes to escape drug control. Armed with this knowledge, strategies to limit the expansion of HIVDR are proposed.
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Affiliation(s)
- D A Collier
- Division of Infection and Immunity, University College London, London, UK
| | - C Monit
- Division of Infection and Immunity, University College London, London, UK
| | - R K Gupta
- Department of Medicine, University of Cambridge, Cambridge, UK.
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20
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Einav T, Yazdi S, Coey A, Bjorkman PJ, Phillips R. Harnessing Avidity: Quantifying the Entropic and Energetic Effects of Linker Length and Rigidity for Multivalent Binding of Antibodies to HIV-1. Cell Syst 2019; 9:466-474.e7. [PMID: 31668801 PMCID: PMC6892280 DOI: 10.1016/j.cels.2019.09.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Revised: 09/10/2019] [Accepted: 09/17/2019] [Indexed: 12/13/2022]
Abstract
IgG antibodies increase their apparent affinities by using both of their Fabs to simultaneously attach to antigens. HIV-1 foils this strategy by having few, and highly separated, Envelope (Env) spike targets for antibodies, forcing most IgGs to bind monovalently. Here, we develop a statistical mechanics model of synthetic diFabs joined by DNA linkers of different lengths and flexibilities. This framework enables us to translate the energetic and entropic effects of the linker into the neutralization potency of a diFab. We demonstrate that the strongest neutralization potencies are predicted to require a rigid linker that optimally spans the distance between two Fab binding sites on an Env trimer and that avidity can be further boosted by incorporating more Fabs into these constructs. These results inform the design of multivalent anti-HIV-1 therapeutics that utilize avidity effects to remain potent against HIV-1 in the face of the rapid mutation of Env spikes. Synthetic antibodies that bivalently bind to HIV-1 can markedly enhance avidity Linkers that enable bivalent binding are fully characterized by the linker entropy Properly sized rigid linkers outperform long, flexible linkers Avidity can be further enhanced by increasing antibody valency
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Affiliation(s)
- Tal Einav
- Department of Physics, California Institute of Technology, Pasadena, CA 91125, USA
| | - Shahrzad Yazdi
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Aaron Coey
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Pamela J Bjorkman
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA.
| | - Rob Phillips
- Department of Physics, California Institute of Technology, Pasadena, CA 91125, USA; Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA; Department of Applied Physics, California Institute of Technology, Pasadena, CA 91125, USA.
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21
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Smith LK, Kuhn TB, Chen J, Bamburg JR. HIV Associated Neurodegenerative Disorders: A New Perspective on the Role of Lipid Rafts in Gp120-Mediated Neurotoxicity. Curr HIV Res 2019; 16:258-269. [PMID: 30280668 PMCID: PMC6398609 DOI: 10.2174/1570162x16666181003144740] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Revised: 09/17/2018] [Accepted: 09/26/2018] [Indexed: 02/07/2023]
Abstract
The implementation of combination antiretroviral therapy (cART) as the primary means of treatment for HIV infection has achieved a dramatic decline in deaths attributed to AIDS and the reduced incidence of severe forms of HIV-associated neurocognitive disorders (HAND) in infected individuals. Despite these advances, milder forms of HAND persist and prevalence of these forms of neurocognitive impairment are rising with the aging population of HIV infected individuals. HIV enters the CNS early in the pathophysiology establishing persistent infection in resident macrophages and glial cells. These infected cells, in turn, secrete neurotoxic viral proteins, inflammatory cytokines, and small metabolites thought to contribute to neurodegenerative processes. The viral envelope protein gp120 has been identified as a potent neurotoxin affecting neurodegeneration via indirect and direct mechanisms involving interactions with chemokine co-receptors CCR5 and CXCR4. This short review focuses on gp120 neurotropism and associated mechanisms of neurotoxicity linked to chemokine receptors CCR5 and CXCR4 with a new perspective on plasma membrane lipid rafts as an active participant in gp120-mediated neurodegeneration underlying HIV induced CNS pathology.
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Affiliation(s)
- Lisa K Smith
- Department of Chemistry and Biochemistry, University of Alaska Fairbanks, Fairbanks, AK, United States
| | - Thomas B Kuhn
- Department of Chemistry and Biochemistry, University of Alaska Fairbanks, Fairbanks, AK, United States
| | - Jack Chen
- Department of Biology and Wildlife, Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, AK, United States
| | - James R Bamburg
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO, United States
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22
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Gorai B, Das S, Maiti PK. Prediction and validation of HIV-1 gp41 ecto-transmembrane domain post-fusion trimeric structure using molecular modeling. J Biomol Struct Dyn 2019; 38:2592-2603. [DOI: 10.1080/07391102.2019.1635916] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Biswajit Gorai
- Department of Physics, Indian Institute of Science, Bangalore, Karnataka, India
| | - Satyabrata Das
- Department of Physics, Indian Institute of Science, Bangalore, Karnataka, India
| | - Prabal K. Maiti
- Department of Physics, Indian Institute of Science, Bangalore, Karnataka, India
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23
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Quantifying Anti-HIV Envelope-Specific Antibodies in Plasma from HIV Infected Individuals. Viruses 2019; 11:v11060487. [PMID: 31141927 PMCID: PMC6631318 DOI: 10.3390/v11060487] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 05/21/2019] [Accepted: 05/25/2019] [Indexed: 12/15/2022] Open
Abstract
Quantifying HIV Envelope (Env)-specific antibodies in HIV+ plasma is useful for interpreting antibody dependent cellular cytotoxicity assay results. HIV Env, the only viral protein expressed on the surface of infected cells, has a native trimeric closed conformation on cells infected with wild-type HIV. However, CD4+ uninfected bystander cells in HIV+ cell cultures bind gp120 shed from HIV+ cells exposing CD4-induced epitopes normally hidden in native Env. We used flow-cytometry based assays to quantify antibodies in HIV+ plasma specific for native trimeric Env or gp120/CD4 conjugates using CEM.NKr.CCR5 (CEM) cells infected with HIV (iCEM) or coated with recombinant gp120 (cCEM), as a surrogate for gp120+ HIV- bystander cells. Results from both assays were compared to those of a plate-based ELISA to monomeric gp120. The levels of Env-specific antibodies to cCEM and iCEM, measured by flow cytometry, and to gp120 by ELISA were positively correlated. More antibodies in HIV+ plasma recognized the gp120 conformation exposed on cCEM than on iCEM. Comparisons of plasma from untreated progressors, treated progressors, and elite controllers revealed that antibodies to Env epitopes were the lowest in treated progressors. Plasma from elite controllers and untreated progressors had similarly high levels of Env-specific antibodies, despite elite controllers having undetectable HIV viral loads, while untreated progressors maintained high viral loads.
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24
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Conformational Engineering of HIV-1 Env Based on Mutational Tolerance in the CD4 and PG16 Bound States. J Virol 2019; 93:JVI.00219-19. [PMID: 30894475 DOI: 10.1128/jvi.00219-19] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Accepted: 03/16/2019] [Indexed: 12/22/2022] Open
Abstract
HIV-1 infection is initiated by viral Env engaging the host receptor CD4, triggering Env to transition from a "closed" to "open" conformation during the early events of virus-cell membrane fusion. To understand how Env sequence accommodates this conformational change, mutational landscapes decoupled from virus replication were determined for Env from BaL (clade B) and DU422 (clade C) isolates interacting with CD4 or antibody PG16 that preferentially recognizes closed trimers. Sequence features uniquely important to each bound state were identified, including glycosylation and binding sites. Notably, the Env apical domain and trimerization interface are under selective pressure for PG16 binding. Based on this key observation, mutations were found that increase presentation of quaternary epitopes associated with properly conformed trimers when Env is expressed at the plasma membrane. Many mutations reduce electrostatic repulsion at the Env apex and increase PG16 recognition of Env sequences from clades A and B. Other mutations increase hydrophobic packing at the gp120 inner-outer domain interface and were broadly applicable for engineering Env from diverse strains spanning tiers 1, 2, and 3 across clades A, B, C, and BC recombinants. Core mutations predicted to introduce steric strain in the open state show markedly reduced CD4 interactions. Finally, we demonstrate how our methodology can be adapted to interrogate interactions between membrane-associated Env and the matrix domain of Gag. These findings and methods may assist vaccine design.IMPORTANCE HIV-1 Env is dynamic and undergoes large conformational changes that drive fusion of virus and host cell membranes. Three Env proteins in a trimer contact each other at their apical tips to form a closed conformation that presents epitopes recognized by broadly neutralizing antibodies. The apical tips separate, among other changes, to form an open conformation that binds tightly to host receptors. Understanding how Env sequence facilitates these structural changes can inform the biophysical mechanism and aid immunogen design. Using deep mutational scans decoupled from virus replication, we report mutational landscapes for Env from two strains interacting with conformation-dependent binding proteins. Residues in the Env trimer interface and apical domains are preferentially conserved in the closed conformation, and conformational diversity is facilitated by electrostatic repulsion and an underpacked core between domains. Specific mutations are described that enhance presentation of the trimeric closed conformation across diverse HIV-1 strains.
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25
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Zhou JO, Ton T, Morriss JW, Nguyen D, Fera D. Structural Insights from HIV-Antibody Coevolution and Related Immunization Studies. AIDS Res Hum Retroviruses 2018; 34:760-768. [PMID: 29984587 DOI: 10.1089/aid.2018.0097] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Human immunodeficiency virus type 1 (HIV-1) is a rapidly evolving pathogen that causes acquired immunodeficiency syndrome (AIDS) in humans. There are ∼30-35 million people infected with HIV around the world, and ∼25 million have died since the first reported cases in 1981. In addition, each year 2-3 million people become newly infected, and >1 million die of AIDS. An HIV-1 vaccine would help halt an AIDS pandemic, and efforts to develop a vaccine have focused on targeting the HIV-1 envelope, Env, found on the surface of the virus. A number of chronically infected individuals have been shown to produce antibodies, called broadly neutralizing antibodies (bnAbs), that target many strains of HIV-1 by binding to Env, thus suggesting promise for HIV-1 vaccine development. BnAbs take years to develop, and have a number of traits that inhibit their production; thus, a number of researchers are trying to understand the pathways that result in bnAb production, so that they can be elicited more rapidly by vaccination. This review discusses results and implications from two HIV-1-infected individuals studied longitudinally who produced bnAbs against two different sites on HIV-1 Env, and immunization studies that used Envs derived from those individuals.
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Affiliation(s)
- Jeffrey O. Zhou
- Department of Chemistry and Biochemistry, Swarthmore College, Swarthmore, Pennsylvania
| | - Therese Ton
- Department of Biology, Swarthmore College, Swarthmore, Pennsylvania
| | - Julia W. Morriss
- Department of Chemistry and Biochemistry, Swarthmore College, Swarthmore, Pennsylvania
- Department of Biology, Swarthmore College, Swarthmore, Pennsylvania
| | - Diep Nguyen
- Department of Chemistry and Biochemistry, Swarthmore College, Swarthmore, Pennsylvania
| | - Daniela Fera
- Department of Chemistry and Biochemistry, Swarthmore College, Swarthmore, Pennsylvania
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26
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Moyo T, Ereño-Orbea J, Jacob RA, Pavillet CE, Kariuki SM, Tangie EN, Julien JP, Dorfman JR. Molecular Basis of Unusually High Neutralization Resistance in Tier 3 HIV-1 Strain 253-11. J Virol 2018; 92:e02261-17. [PMID: 29618644 PMCID: PMC6026760 DOI: 10.1128/jvi.02261-17] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2017] [Accepted: 02/26/2018] [Indexed: 01/06/2023] Open
Abstract
Understanding the mechanisms used by HIV-1 to evade antibody neutralization may contribute to the design of a high-coverage vaccine. The tier 3 virus 253-11 is poorly neutralized by subtype-matched and subtype C sera, even compared to other tier 3 viruses, and is also recognized poorly by V3/glycan-targeting monoclonal antibodies (MAbs). We found that sequence polymorphisms in the V3 loop and N-linked glycosylation sites contribute only minimally to the high neutralization resistance of 253-11. Interestingly, the 253-11 membrane-proximal external region (MPER) is rarely recognized by sera in the context of the wild-type virus but is commonly recognized in the context of an HIV-2 chimera, suggesting steric or kinetic hindrance of binding to MPER in the native envelope (Env). Mutations in the 253-11 MPER, which were previously reported to increase the lifetime of the prefusion Env conformation, affected the resistance of 253-11 to antibodies targeting various epitopes on HIV-1 Env, presumably destabilizing its otherwise stable, closed trimer structure. To gain insight into the structure of 253-11, we constructed and crystallized a recombinant 253-11 SOSIP trimer. The resulting structure revealed that the heptad repeat helices in gp41 are drawn in close proximity to the trimer axis and that gp120 protomers also showed a relatively compact disposition around the trimer axis. These observations give substantial insight into the molecular features of an envelope spike from a tier 3 virus and into possible mechanisms that may contribute to its unusually high neutralization resistance.IMPORTANCE HIV-1 isolates that are highly resistant to broadly neutralizing antibodies could limit the efficacy of an antibody-based vaccine. We studied 253-11, which is highly resistant to commonly elicited neutralizing antibodies. To further understand its resistance, we made mutations that are known to delay fusion and thus increase the time that the virus spends in the open conformation following CD4 binding. Interestingly, we found that these mutations affect the 253-11 envelope (Env) spike before CD4 binding, presumably by destabilizing the trimer structure. To gain further information about the structure of the 253-11 Env trimer, we generated a recombinant 253-11 SOSIP trimer. The crystal structure of the SOSIP trimer revealed that the gp41 helices and the gp120 protomers were drawn in toward the center of the molecule compared to most solved HIV-1 Env structures. These observations provide insight into the distinct molecular features of a tier 3 envelope spike.
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Affiliation(s)
- Thandeka Moyo
- Division of Immunology, Department of Pathology, University of Cape Town, Cape Town, South Africa
| | - June Ereño-Orbea
- Program in Molecular Medicine, The Hospital for Sick Children Research Institute, Toronto, Ontario, Canada
| | - Rajesh Abraham Jacob
- Division of Immunology, Department of Pathology, University of Cape Town, Cape Town, South Africa
- International Centre for Genetic Engineering and Biotechnology, Cape Town, South Africa
| | - Clara E Pavillet
- Program in Molecular Medicine, The Hospital for Sick Children Research Institute, Toronto, Ontario, Canada
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Samuel Mundia Kariuki
- Division of Immunology, Department of Pathology, University of Cape Town, Cape Town, South Africa
- International Centre for Genetic Engineering and Biotechnology, Cape Town, South Africa
- Department of Biological Science, University of Eldoret, Eldoret, Kenya
| | - Emily N Tangie
- Division of Immunology, Department of Pathology, University of Cape Town, Cape Town, South Africa
- International Centre for Genetic Engineering and Biotechnology, Cape Town, South Africa
| | - Jean-Philippe Julien
- Program in Molecular Medicine, The Hospital for Sick Children Research Institute, Toronto, Ontario, Canada
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
- Department of Immunology, University of Toronto, Toronto, Ontario, Canada
| | - Jeffrey R Dorfman
- Division of Immunology, Department of Pathology, University of Cape Town, Cape Town, South Africa
- Division of Immunology, School of Pathology, University of the Witwatersrand, Johannesburg, South Africa
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27
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Heredia JD, Park J, Brubaker RJ, Szymanski SK, Gill KS, Procko E. Mapping Interaction Sites on Human Chemokine Receptors by Deep Mutational Scanning. THE JOURNAL OF IMMUNOLOGY 2018; 200:3825-3839. [PMID: 29678950 DOI: 10.4049/jimmunol.1800343] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Accepted: 03/30/2018] [Indexed: 02/02/2023]
Abstract
Chemokine receptors CXCR4 and CCR5 regulate WBC trafficking and are engaged by the HIV-1 envelope glycoprotein gp120 during infection. We combine a selection of human CXCR4 and CCR5 libraries comprising nearly all of ∼7000 single amino acid substitutions with deep sequencing to define sequence-activity landscapes for surface expression and ligand interactions. After consideration of sequence constraints for surface expression, known interaction sites with HIV-1-blocking Abs were appropriately identified as conserved residues following library sorting for Ab binding, validating the use of deep mutational scanning to map functional interaction sites in G protein-coupled receptors. Chemokine CXCL12 was found to interact with residues extending asymmetrically into the CXCR4 ligand-binding cavity, similar to the binding surface of CXCR4 recognized by an antagonistic viral chemokine previously observed crystallographically. CXCR4 mutations distal from the chemokine binding site were identified that enhance chemokine recognition. This included disruptive mutations in the G protein-coupling site that diminished calcium mobilization, as well as conservative mutations to a membrane-exposed site (CXCR4 residues H792.45 and W1614.50) that increased ligand binding without loss of signaling. Compared with CXCR4-CXCL12 interactions, CCR5 residues conserved for gp120 (HIV-1 BaL strain) interactions map to a more expansive surface, mimicking how the cognate chemokine CCL5 makes contacts across the entire CCR5 binding cavity. Acidic substitutions in the CCR5 N terminus and extracellular loops enhanced gp120 binding. This study demonstrates how comprehensive mutational scanning can define functional interaction sites on receptors, and novel mutations that enhance receptor activities can be found simultaneously.
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Affiliation(s)
- Jeremiah D Heredia
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801
| | - Jihye Park
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801
| | - Riley J Brubaker
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801
| | - Steven K Szymanski
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801
| | - Kevin S Gill
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801
| | - Erik Procko
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801
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28
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Cyrklaff M, Frischknecht F, Kudryashev M. Functional insights into pathogen biology from 3D electron microscopy. FEMS Microbiol Rev 2018; 41:828-853. [PMID: 28962014 DOI: 10.1093/femsre/fux041] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Accepted: 07/25/2017] [Indexed: 01/10/2023] Open
Abstract
In recent years, novel imaging approaches revolutionised our understanding of the cellular and molecular biology of microorganisms. These include advances in fluorescent probes, dynamic live cell imaging, superresolution light and electron microscopy. Currently, a major transition in the experimental approach shifts electron microscopy studies from a complementary technique to a method of choice for structural and functional analysis. Here we review functional insights into the molecular architecture of viruses, bacteria and parasites as well as interactions with their respective host cells gained from studies using cryogenic electron tomography and related methodologies.
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Affiliation(s)
- Marek Cyrklaff
- Integrative Parasitology, Center for Infectious Diseases, Heidelberg University Medical School, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany
| | - Friedrich Frischknecht
- Integrative Parasitology, Center for Infectious Diseases, Heidelberg University Medical School, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany
| | - Mikhail Kudryashev
- Max Planck Institute of Biophysics, Max-von-Laue Strasse 3, 60438 Frankfurt, Germany.,Buchmann Institute for Molecular Life Sciences, Goethe University of Frankfurt, Max-von-Laue Strasse 17, 60438 Frankfurt, Germany
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29
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Abstract
The spread of bacterial resistance to antibiotics poses the need for antimicrobial discovery. With traditional search paradigms being exhausted, approaches that are altogether different from antibiotics may offer promising and creative solutions. Here, we introduce a de novo peptide topology that—by emulating the virus architecture—assembles into discrete antimicrobial capsids. Using the combination of high-resolution and real-time imaging, we demonstrate that these artificial capsids assemble as 20-nm hollow shells that attack bacterial membranes and upon landing on phospholipid bilayers instantaneously (seconds) convert into rapidly expanding pores causing membrane lysis (minutes). The designed capsids show broad antimicrobial activities, thus executing one primary function—they destroy bacteria on contact. With the growing threat of antibiotic resistance, unconventional approaches to antimicrobial discovery are needed. Here, the authors present a peptide topology that mimics virus architecture and assembles into antimicrobial capsids that disrupt bacterial membranes upon contact.
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30
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Murphy RE, Samal AB, Vlach J, Saad JS. Solution Structure and Membrane Interaction of the Cytoplasmic Tail of HIV-1 gp41 Protein. Structure 2017; 25:1708-1718.e5. [PMID: 29056482 DOI: 10.1016/j.str.2017.09.010] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2017] [Revised: 08/17/2017] [Accepted: 09/18/2017] [Indexed: 10/18/2022]
Abstract
The cytoplasmic tail of gp41 (gp41CT) remains the last HIV-1 domain with an unknown structure. It plays important roles in HIV-1 replication such as mediating envelope (Env) intracellular trafficking and incorporation into assembling virions, mechanisms of which are poorly understood. Here, we present the solution structure of gp41CT in a micellar environment and characterize its interaction with the membrane. We show that the N-terminal 45 residues are unstructured and not associated with the membrane. However, the C-terminal 105 residues form three membrane-bound amphipathic α helices with distinctive structural features such as variable degree of membrane penetration, hydrophobic and basic surfaces, clusters of aromatic residues, and a network of cation-π interactions. This work fills a major gap by providing the structure of the last segment of HIV-1 Env, which will provide insights into the mechanisms of Gag-mediated Env incorporation as well as the overall Env mobility and conformation on the virion surface.
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Affiliation(s)
- R Elliot Murphy
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Alexandra B Samal
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Jiri Vlach
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Jamil S Saad
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA.
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31
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Jia M, Shaw T, Zhang X, Liu D, Shen Y, Ezeamama AE, Yang C, Zhang M. Decoding noises in HIV computational genotyping. Virology 2017; 511:249-255. [PMID: 28918303 DOI: 10.1016/j.virol.2017.08.031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Revised: 08/22/2017] [Accepted: 08/23/2017] [Indexed: 10/18/2022]
Abstract
Lack of a consistent and reliable genotyping system can critically impede HIV genomic research on pathogenesis, fitness, virulence, drug resistance, and genomic-based healthcare and treatment. At present, mis-genotyping, i.e., background noises in molecular genotyping, and its impact on epidemic surveillance is unknown. For the first time, we present a comprehensive assessment of HIV genotyping quality. HIV sequence data were retrieved from worldwide published records, and subjected to a systematic genotyping assessment pipeline. Results showed that mis-genotyped cases occurred at 4.6% globally, with some regional and high-risk population heterogeneities. Results also revealed a consistent mis-genotyping pattern in gp120 in all studied populations except the group of men who have sex with men. Our study also suggests novel virus diversities in the mis-genotyped cases. Finally, this study reemphasizes the importance of implementing a standardized genotyping pipeline to avoid genotyping disparity and to advance our understanding of virus evolution in various epidemiological settings.
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Affiliation(s)
- MingRui Jia
- Department of Pain Management, Shandong Provincial Hospital Affiliated to Shandong University, 324 Jingwu Road, Jinan, Shandong Province 250021, China; Department of Epidemiology and Biostatistics, University of Georgia, GA 30602, USA
| | - Timothy Shaw
- Department of Epidemiology and Biostatistics, University of Georgia, GA 30602, USA
| | - Xing Zhang
- Diagnostic Imaging center, MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Dong Liu
- Department of Epidemiology and Biostatistics, University of Georgia, GA 30602, USA; Laboratory of Ichthyology, Shanghai Ocean University, Shanghai 201306, China
| | - Ye Shen
- Department of Epidemiology and Biostatistics, University of Georgia, GA 30602, USA
| | - Amara E Ezeamama
- Department of Psychiatry, Michigan State University, MI 48824, USA
| | - Chunfu Yang
- International Laboratory Branch, Division of Global HIV/TB, Center for Global Health, Centers for Diseases Control and Prevention, GA 30333, USA
| | - Ming Zhang
- Department of Epidemiology and Biostatistics, University of Georgia, GA 30602, USA.
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32
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Krammer F. Strategies to induce broadly protective antibody responses to viral glycoproteins. Expert Rev Vaccines 2017; 16:503-513. [PMID: 28277797 DOI: 10.1080/14760584.2017.1299576] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
INTRODUCTION Currently, several universal/broadly protective influenza virus vaccine candidates are under development. Many of these vaccines are based on strategies to induce protective antibody responses against the surface glycoproteins of antigenically and genetically diverse influenza viruses. These strategies might also be applicable to surface glycoproteins of a broad range of other important viral pathogens. Areas covered: Common strategies include sequential vaccination with divergent antigens, multivalent approaches, vaccination with glycan-modified antigens, vaccination with minimal antigens and vaccination with antigens that have centralized/optimized sequences. Here we review these strategies and the underlying concepts. Furthermore, challenges, feasibility and applicability to other viral pathogens are discussed. Expert commentary: Several broadly protective/universal influenza virus vaccine strategies will be tested in humans in the coming years. If successful in terms of safety and immunological readouts, they will move forward into efficacy trials. In the meantime, successful vaccine strategies might also be applied to other antigenically diverse viruses of concern.
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Affiliation(s)
- F Krammer
- a Department of Microbiology , Icahn School of Medicine at Mount Sinai , New York , NY , USA
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Kesavardhana S, Das R, Citron M, Datta R, Ecto L, Srilatha NS, DiStefano D, Swoyer R, Joyce JG, Dutta S, LaBranche CC, Montefiori DC, Flynn JA, Varadarajan R. Structure-based Design of Cyclically Permuted HIV-1 gp120 Trimers That Elicit Neutralizing Antibodies. J Biol Chem 2016; 292:278-291. [PMID: 27879316 DOI: 10.1074/jbc.m116.725614] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Revised: 11/18/2016] [Indexed: 11/06/2022] Open
Abstract
A major goal for HIV-1 vaccine development is an ability to elicit strong and durable broadly neutralizing antibody (bNAb) responses. The trimeric envelope glycoprotein (Env) spikes on HIV-1 are known to contain multiple epitopes that are susceptible to bNAbs isolated from infected individuals. Nonetheless, all trimeric and monomeric Env immunogens designed to date have failed to elicit such antibodies. We report the structure-guided design of HIV-1 cyclically permuted gp120 that forms homogeneous, stable trimers, and displays enhanced binding to multiple bNAbs, including VRC01, VRC03, VRC-PG04, PGT128, and the quaternary epitope-specific bNAbs PGT145 and PGDM1400. Constructs that were cyclically permuted in the V1 loop region and contained an N-terminal trimerization domain to stabilize V1V2-mediated quaternary interactions, showed the highest homogeneity and the best antigenic characteristics. In guinea pigs, a DNA prime-protein boost regimen with these new gp120 trimer immunogens elicited potent neutralizing antibody responses against highly sensitive Tier 1A isolates and weaker neutralizing antibody responses with an average titer of about 115 against a panel of heterologous Tier 2 isolates. A modest fraction of the Tier 2 virus neutralizing activity appeared to target the CD4 binding site on gp120. These results suggest that cyclically permuted HIV-1 gp120 trimers represent a viable platform in which further modifications may be made to eventually achieve protective bNAb responses.
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Affiliation(s)
- Sannula Kesavardhana
- From the Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560 012, India
| | - Raksha Das
- From the Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560 012, India
| | - Michael Citron
- Merck & Company, Inc., West Point, Pennsylvania 19486, and
| | - Rohini Datta
- From the Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560 012, India
| | - Linda Ecto
- Merck & Company, Inc., West Point, Pennsylvania 19486, and
| | | | | | - Ryan Swoyer
- Merck & Company, Inc., West Point, Pennsylvania 19486, and
| | - Joseph G Joyce
- Merck & Company, Inc., West Point, Pennsylvania 19486, and
| | - Somnath Dutta
- From the Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560 012, India
| | - Celia C LaBranche
- the Department of Surgery, Duke University, Durham, North Carolina 27705
| | - David C Montefiori
- the Department of Surgery, Duke University, Durham, North Carolina 27705
| | | | - Raghavan Varadarajan
- From the Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560 012, India,
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34
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Learning the Relationship between the Primary Structure of HIV Envelope Glycoproteins and Neutralization Activity of Particular Antibodies by Using Artificial Neural Networks. Int J Mol Sci 2016; 17:ijms17101710. [PMID: 27727189 PMCID: PMC5085742 DOI: 10.3390/ijms17101710] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2016] [Revised: 09/26/2016] [Accepted: 10/03/2016] [Indexed: 12/02/2022] Open
Abstract
The dependency between the primary structure of HIV envelope glycoproteins (ENV) and the neutralization data for given antibodies is very complicated and depends on a large number of factors, such as the binding affinity of a given antibody for a given ENV protein, and the intrinsic infection kinetics of the viral strain. This paper presents a first approach to learning these dependencies using an artificial feedforward neural network which is trained to learn from experimental data. The results presented here demonstrate that the trained neural network is able to generalize on new viral strains and to predict reliable values of neutralizing activities of given antibodies against HIV-1.
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35
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Louis JM, Baber JL, Ghirlando R, Aniana A, Bax A, Roche J. Insights into the Conformation of the Membrane Proximal Regions Critical to the Trimerization of the HIV-1 gp41 Ectodomain Bound to Dodecyl Phosphocholine Micelles. PLoS One 2016; 11:e0160597. [PMID: 27513582 PMCID: PMC4981318 DOI: 10.1371/journal.pone.0160597] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Accepted: 07/21/2016] [Indexed: 01/06/2023] Open
Abstract
The transitioning of the ectodomain of gp41 from a pre-hairpin to a six-helix bundle conformation is a crucial aspect of virus-cell fusion. To gain insight into the intermediary steps of the fusion process we have studied the pH and dodecyl phosphocholine (DPC) micelle dependent trimer association of gp41 by systematic deletion analysis of an optimized construct termed 17-172 (residues 528 to 683 of Env) that spans the fusion peptide proximal region (FPPR) to the membrane proximal external region (MPER) of gp41, by sedimentation velocity and double electron-electron resonance (DEER) EPR spectroscopy. Trimerization at pH 7 requires the presence of both the FPPR and MPER regions. However, at pH 4, the protein completely dissociates to monomers. DEER measurements reveal a partial fraying of the C-terminal MPER residues in the 17-172 trimer while the other regions, including the FPPR, remain compact. In accordance, truncating nine C-terminal MPER residues (675-683) in the 17-172 construct does not shift the trimer-monomer equilibrium significantly. Thus, in the context of the gp41 ectodomain spanning residues 17-172, trimerization is clearly dependent on FPPR and MPER regions even when the terminal residues of MPER unravel. The antibody Z13e1, which spans both the 2F5 and 4E10 epitopes in MPER, binds to 17-172 with a Kd of 1 ± 0.12 μM. Accordingly, individual antibodies 2F5 and 4E10 also recognize the 17-172 trimer/DPC complex. We propose that binding of the C-terminal residues of MPER to the surface of the DPC micelles models a correct positioning of the trimeric transmembrane domain anchored in the viral membrane.
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Affiliation(s)
- John M. Louis
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
- * E-mail: (JL)); (JR)
| | - James L. Baber
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Rodolfo Ghirlando
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Annie Aniana
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Ad Bax
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Julien Roche
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, Iowa, United States of America
- * E-mail: (JL)); (JR)
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36
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Affiliation(s)
- Kelly K. Lee
- Department of Medicinal Chemistry, University of Washington, Seattle, Washington, United States of America
- Biological Structure Physics and Design Program, University of Washington, Seattle, Washington, United States of America
- * E-mail:
| | - Long Gui
- Department of Medicinal Chemistry, University of Washington, Seattle, Washington, United States of America
- Biological Structure Physics and Design Program, University of Washington, Seattle, Washington, United States of America
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Takeda S, Takizawa M, Miyauchi K, Urano E, Fujino M, Murakami T, Murakami T, Komano J. Conformational properties of the third variable loop of HIV-1AD8 envelope glycoprotein in the liganded conditions. Biochem Biophys Res Commun 2016; 475:113-8. [PMID: 27178216 DOI: 10.1016/j.bbrc.2016.05.051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Accepted: 05/10/2016] [Indexed: 10/21/2022]
Abstract
The conformational dynamics of the HIV-1 envelope glycoprotein gp120 and gp41 (Env) remains poorly understood. Here we examined how the V3 loop conformation is regulated in the liganded state using a panel of recombinant HIV-1NL4-3 clones bearing HIV-1AD8 Env by two experimental approaches, one adopting a monoclonal neutralizing antibody KD-247 (suvizumab) that recognizes the tip of the V3 loop, and the other assessing the function of the V3 loop. A significant positive correlation of the Env-KD-247 binding was detected between the liganded and unliganded conditions. Namely, the mutation D163G located in the V2 loop, which enhances viral susceptibility to KD-247 by 59.4-fold, had little effect on the sCD4-induced increment of the virus-KD-247 binding. By contrast, a virus with the S370N mutation in the C3 region increased the virus-KD-247 binding by 91.4-fold, although it did not influence the KD-247-mediated neutralization. Co-receptor usage and the susceptibility to CCR5 inhibitor Maraviroc were unaffected by D163G and S370N mutations. Collectively, these data suggest that the conformation of the liganded V3-loop of HIV-1AD8 Env is still under regulation of other Env domains aside from the V3 loop, including V2 and C3. Our results give an insight into the structural properties of HIV-1 Env and viral resistance to entry inhibitors by non-V3 loop mutations.
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Affiliation(s)
- Satoshi Takeda
- AIDS Research Center, National Institute of Infectious Diseases, 1-23-1 Toyama Shinjuku, Tokyo, 162-0053, Japan
| | - Mari Takizawa
- AIDS Research Center, National Institute of Infectious Diseases, 1-23-1 Toyama Shinjuku, Tokyo, 162-0053, Japan
| | - Kosuke Miyauchi
- Laboratory for Cytokine Regulation, Research Center for Integrative Medical Science (IMS), RIKEN Yokohama Institute, Suehiro-cho 1-7-22, Tsurumi, Yokohama, Kanagawa, 230-0045, Japan
| | - Emiko Urano
- AIDS Research Center, National Institute of Infectious Diseases, 1-23-1 Toyama Shinjuku, Tokyo, 162-0053, Japan
| | - Masayuki Fujino
- AIDS Research Center, National Institute of Infectious Diseases, 1-23-1 Toyama Shinjuku, Tokyo, 162-0053, Japan
| | - Toshio Murakami
- The Chemo-Sero-Therapeutic Research Institute, 1314-1 Kawabe Kyokushi, Kikuchi, Kumamoto, 869-1298, Japan
| | - Tsutomu Murakami
- AIDS Research Center, National Institute of Infectious Diseases, 1-23-1 Toyama Shinjuku, Tokyo, 162-0053, Japan
| | - Jun Komano
- AIDS Research Center, National Institute of Infectious Diseases, 1-23-1 Toyama Shinjuku, Tokyo, 162-0053, Japan; Department of Clinical Laboratory, Nagoya Medical Center, 1-1 4-Chome, Sannomaru, Naka-ku, Nagoya, 460-0001, Japan.
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Scharf L, Wang H, Gao H, Chen S, McDowall AW, Bjorkman PJ. Broadly Neutralizing Antibody 8ANC195 Recognizes Closed and Open States of HIV-1 Env. Cell 2015; 162:1379-90. [PMID: 26359989 DOI: 10.1016/j.cell.2015.08.035] [Citation(s) in RCA: 115] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2015] [Revised: 06/19/2015] [Accepted: 07/28/2015] [Indexed: 10/23/2022]
Abstract
The HIV-1 envelope (Env) spike contains limited epitopes for broadly neutralizing antibodies (bNAbs); thus, most neutralizing antibodies are strain specific. The 8ANC195 epitope, defined by crystal and electron microscopy (EM) structures of bNAb 8ANC195 complexed with monomeric gp120 and trimeric Env, respectively, spans the gp120 and gp41 Env subunits. To investigate 8ANC195's gp41 epitope at higher resolution, we solved a 3.58 Å crystal structure of 8ANC195 complexed with fully glycosylated Env trimer, revealing 8ANC195 insertion into a glycan shield gap to contact gp120 and gp41 glycans and protein residues. To determine whether 8ANC195 recognizes the CD4-bound open Env conformation that leads to co-receptor binding and fusion, one of several known conformations of virion-associated Env, we solved EM structures of an Env/CD4/CD4-induced antibody/8ANC195 complex. 8ANC195 binding partially closed the CD4-bound trimer, confirming structural plasticity of Env by revealing a previously unseen conformation. 8ANC195's ability to bind different Env conformations suggests advantages for potential therapeutic applications.
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Affiliation(s)
- Louise Scharf
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Haoqing Wang
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Han Gao
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Songye Chen
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Alasdair W McDowall
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA; Howard Hughes Medical Institute, California Institute of Technology, Pasadena, CA 91125, USA
| | - Pamela J Bjorkman
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA.
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Park H, Chung YS, Yoon CH, Lee SH, Kim SS, Kang C, Choi BS. Presentation of available CTL epitopes that induction of cell-mediated immune response against HIV-1 Koran clade B strain using computational technology. HIV Med 2015; 17:460-6. [PMID: 26471354 DOI: 10.1111/hiv.12316] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/27/2015] [Indexed: 12/31/2022]
Abstract
OBJECTIVE Theoretical predicting cytotoxic T lymphocyte (CTL) epitopes are an important tool in vaccine design and CTL therapy for enhancing our understanding of the cellular immune system. We would like to identify available CTL epitopes against HIV-1 Korean clade B. CTL activity was assessed in freshly isolated peripheral blood mononuclear cells from Korean HIV patients in order to assess whether these CTL epitopes induce a cell-mediated immune response (CMI). METHODS NetCTLpan1.1 software, which is the most popular prediction computer software package, and full atom-based simulation (FABS), which is a 3D modelling system for binding activity between epitopes and human leucocyte antigen (HLA) molecules, were used to predict the peptide-spanning Env region binding to HLA-A*24:02, HLA-A*02:01 and HLA-B*15:01, which are frequently found in the Korean population. Granzyme B and interferon-γ ELISPOT assays were used to determine whether identified CTL epitopes induce CMI. RESULTS Three HIV-1 Korean clade B-specific Env CTL epitopes were identified: Gp41-RYL and Gp41-RQG are localized within gp41, and Gp120-LLQ within gp120. In in vitro assays using granzyme B ELISPOT, Gp120-LLQ and Gp41-RQG induced epitope-specific CTL responses in HLA-restricted cells. In ex vivo assay using IFN-γ ELISPOT, cell-mediated immune responses to Gp41-RYL were present in 50% of HLA-matched patients, and responses to Gp120-LLQ and Gp41-RQG were found in 33% of HLA-matched patients. CONCLUSION In this study, we found that a prediction pipeline for CTL epitopes might be based on the most popular computer prediction software and FABS methods. Our results suggest that these CTL epitopes may provide useful tools and information for the development of a therapeutic vaccine against HIV-1 Korean clade B.
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Affiliation(s)
- H Park
- Division of AIDS, Korea National Institute of Health, Cheongju, Chungbuk, Korea
| | - Y-S Chung
- Division of AIDS, Korea National Institute of Health, Cheongju, Chungbuk, Korea
| | - C-H Yoon
- Division of AIDS, Korea National Institute of Health, Cheongju, Chungbuk, Korea
| | - S H Lee
- Department of Laboratory Medicine, Ulsan University Hospital, University of Ulsan College of Medicine, Ulsan, Korea
| | - S S Kim
- Division of AIDS, Korea National Institute of Health, Cheongju, Chungbuk, Korea
| | - C Kang
- Division of AIDS, Korea National Institute of Health, Cheongju, Chungbuk, Korea
| | - B-S Choi
- Division of AIDS, Korea National Institute of Health, Cheongju, Chungbuk, Korea
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40
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The external domains of the HIV-1 envelope are a mutational cold spot. Nat Commun 2015; 6:8571. [PMID: 26450412 PMCID: PMC4687473 DOI: 10.1038/ncomms9571] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Accepted: 09/07/2015] [Indexed: 01/27/2023] Open
Abstract
In RNA viruses, mutations occur fast and have large fitness effects. While this affords remarkable adaptability, it can also endanger viral survival due to the accumulation of deleterious mutations. How RNA viruses reconcile these two opposed facets of mutation is still unknown. Here we show that, in human immunodeficiency virus (HIV-1), spontaneous mutations are not randomly located along the viral genome. We find that the viral mutation rate experiences a threefold reduction in the region encoding the most external domains of the viral envelope, which are strongly targeted by neutralizing antibodies. This contrasts with the hypermutation mechanisms deployed by other, more slowly mutating pathogens such as DNA viruses and bacteria, in response to immune pressure. We show that downregulation of the mutation rate in HIV-1 is exerted by the template RNA through changes in sequence context and secondary structure, which control the activity of apolipoprotein B mRNA-editing enzyme catalytic polypeptide-like 3 (A3)-mediated cytidine deamination and the fidelity of the viral reverse transcriptase. Mutations allow RNA virus to adapt fast but also entail fitness costs. Geller et al. show that, in HIV-1, mutations occur three times less often in the most external domains of the envelope, and that this is due to changes in RNA sequence context and structure, which control viral and host-encoded mutational mechanisms.
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Conformational Masking and Receptor-Dependent Unmasking of Highly Conserved Env Epitopes Recognized by Non-Neutralizing Antibodies That Mediate Potent ADCC against HIV-1. Viruses 2015; 7:5115-32. [PMID: 26393642 PMCID: PMC4584300 DOI: 10.3390/v7092856] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Revised: 08/12/2015] [Accepted: 08/18/2015] [Indexed: 01/11/2023] Open
Abstract
The mechanism of antibody-mediated protection is a major focus of HIV-1 vaccine development and a significant issue in the control of viremia. Virus neutralization, Fc-mediated effector function, or both, are major mechanisms of antibody-mediated protection against HIV-1, although other mechanisms, such as virus aggregation, are known. The interplay between virus neutralization and Fc-mediated effector function in protection against HIV-1 is complex and only partially understood. Passive immunization studies using potent broadly neutralizing antibodies (bnAbs) show that both neutralization and Fc-mediated effector function provides the widest dynamic range of protection; however, a vaccine to elicit these responses remains elusive. By contrast, active immunization studies in both humans and non-human primates using HIV-1 vaccine candidates suggest that weakly neutralizing or non-neutralizing antibodies can protect by Fc-mediated effector function, albeit with a much lower dynamic range seen for passive immunization with bnAbs. HIV-1 has evolved mechanisms to evade each type of antibody-mediated protection that must be countered by a successful AIDS vaccine. Overcoming the hurdles required to elicit bnAbs has become a major focus of HIV-1 vaccine development. Here, we discuss a less studied problem, the structural basis of protection (and its evasion) by antibodies that protect only by potent Fc-mediated effector function.
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Zhang W, Cao S, Martin JL, Mueller JD, Mansky LM. Morphology and ultrastructure of retrovirus particles. AIMS BIOPHYSICS 2015; 2:343-369. [PMID: 26448965 PMCID: PMC4593330 DOI: 10.3934/biophy.2015.3.343] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Retrovirus morphogenesis entails assembly of Gag proteins and the viral genome on the host plasma membrane, acquisition of the viral membrane and envelope proteins through budding, and formation of the core through the maturation process. Although in both immature and mature retroviruses, Gag and capsid proteins are organized as paracrystalline structures, the curvatures of these protein arrays are evidently not uniform within one or among all virus particles. The heterogeneity of retroviruses poses significant challenges to studying the protein contacts within the Gag and capsid lattices. This review focuses on current understanding of the molecular organization of retroviruses derived from the sub-nanometer structures of immature virus particles, helical capsid protein assemblies and soluble envelope protein complexes. These studies provide insight into the molecular elements that maintain the stability, flexibility and infectivity of virus particles. Also reviewed are morphological studies of retrovirus budding, maturation, infection and cell-cell transmission, which inform the structural transformation of the viruses and the cells during infection and viral transmission, and lead to better understanding of the interplay between the functioning viral proteins and the host cell.
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Affiliation(s)
- Wei Zhang
- Institute for Molecular Virology, University of Minnesota, Minneapolis, MN, USA ; Department of Diagnostic and Biological Sciences, School of Dentistry, University of Minnesota, Minneapolis, MN, USA ; Characterization Facility, University of Minnesota, Minneapolis, MN, USA
| | - Sheng Cao
- Wuhan Institute of Virology, Chinese Academy of Science, Wuhan, China
| | - Jessica L Martin
- Institute for Molecular Virology, University of Minnesota, Minneapolis, MN, USA ; Pharmacology Graduate Program, University of Minnesota, Minneapolis, MN, USA
| | - Joachim D Mueller
- Institute for Molecular Virology, University of Minnesota, Minneapolis, MN, USA ; School of Physics and Astronomy, University of Minnesota, Minneapolis, MN, USA
| | - Louis M Mansky
- Institute for Molecular Virology, University of Minnesota, Minneapolis, MN, USA ; Department of Diagnostic and Biological Sciences, School of Dentistry, University of Minnesota, Minneapolis, MN, USA ; Pharmacology Graduate Program, University of Minnesota, Minneapolis, MN, USA ; Department of Microbiology, University of Minnesota, Minneapolis, MN, USA
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Gruschus JM, Byrd RA, Randazzo PA. The importance of seeing surface (effects). Structure 2015; 22:363-5. [PMID: 24607142 DOI: 10.1016/j.str.2014.02.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
In this issue of Structure, Liu and colleagues describe an experimentally rigorous and innovative approach for understanding the role of membranes in the function and regulation of peripheral membrane proteins. This work is the beginning of a new era of experimental work that promises many advances relevant to molecular mechanisms and therapeutic targeting of this important class of proteins.
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Affiliation(s)
- James M Gruschus
- Biochemistry and Biophysics Center, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - R Andrew Byrd
- Structural Biophysics Laboratory, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Paul A Randazzo
- Laboratory of Cellular and Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA.
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Lewis GK. Honing a harder-hitting hammerhead improves broadly neutralizing antibody breadth and potency. J Clin Invest 2015; 125:2271-4. [PMID: 25985269 DOI: 10.1172/jci82057] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
While current HIV-1 therapies have greatly improved the quality and duration of life for infected individuals, a vaccine to prevent transmission of the virus is lacking. Broadly neutralizing monoclonal antibodies (bnmAbs) with the capacity to neutralize multiple HIV-1 variants have been isolated from HIV-1-infected individuals, and there has been a great effort to investigate how these bnmAbs arise, due their potential for HIV-1 vaccination. In this issue of the JCI, Willis and colleagues apply a computational approach to design variants of the bnmAb PG9 in an attempt to enhance potency and neutralization breadth. One of these variants was able to target multiple PG9-resistant strains, as the result of stabilization of the long heavy chain complementarity determining region 3 (HCDR3). The results of this study provide important insight and a unique approach to optimizing HIV-1 bnmABs.
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45
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Matsuda Z. Recent advance in the structural analysis of HIV-1 envelope protein. SCIENCE CHINA-LIFE SCIENCES 2015; 58:420-4. [PMID: 25921945 DOI: 10.1007/s11427-015-4852-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Accepted: 03/03/2015] [Indexed: 02/07/2023]
Abstract
Human immunodeficiency virus type I (HIV-1), a causative agent of AIDS, is affecting today more than 35 millions of people worldwide. The advance of anti-HIV chemotherapy has made AIDS a chronic non-fatal disease in resourceful countries. Long-awaited anti-HIV-1 vaccine is still not with us yet; however, great progress in structural analyses of the envelope protein of HIV-1 in recent years starts to shed light on rational intervention targeted at the envelope protein, as will be reviewed in this article.
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Affiliation(s)
- Zene Matsuda
- Research Center for Asian Infectious Diseases, Institute of Medical Science, the University of Tokyo, Tokyo, 108-8639, Japan,
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Galimidi RP, Klein JS, Politzer MS, Bai S, Seaman MS, Nussenzweig MC, West AP, Bjorkman PJ. Intra-spike crosslinking overcomes antibody evasion by HIV-1. Cell 2015; 160:433-46. [PMID: 25635457 DOI: 10.1016/j.cell.2015.01.016] [Citation(s) in RCA: 100] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Revised: 11/21/2014] [Accepted: 12/16/2014] [Indexed: 10/24/2022]
Abstract
Antibodies developed during HIV-1 infection lose efficacy as the viral spike mutates. We postulated that anti-HIV-1 antibodies primarily bind monovalently because HIV's low spike density impedes bivalent binding through inter-spike crosslinking, and the spike structure prohibits bivalent binding through intra-spike crosslinking. Monovalent binding reduces avidity and potency, thus expanding the range of mutations permitting antibody evasion. To test this idea, we engineered antibody-based molecules capable of bivalent binding through intra-spike crosslinking. We used DNA as a "molecular ruler" to measure intra-epitope distances on virion-bound spikes and construct intra-spike crosslinking molecules. Optimal bivalent reagents exhibited up to 2.5 orders of magnitude increased potency (>100-fold average increases across virus panels) and identified conformational states of virion-bound spikes. The demonstration that intra-spike crosslinking lowers the concentration of antibodies required for neutralization supports the hypothesis that low spike densities facilitate antibody evasion and the use of molecules capable of intra-spike crosslinking for therapy or passive protection.
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Affiliation(s)
- Rachel P Galimidi
- Division of Biology and Biological Engineering, California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125, USA
| | - Joshua S Klein
- Division of Biology and Biological Engineering, California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125, USA
| | - Maria S Politzer
- Division of Biology and Biological Engineering, California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125, USA
| | - Shiyu Bai
- Division of Biology and Biological Engineering, California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125, USA
| | | | - Michel C Nussenzweig
- Laboratory of Molecular Immunology, The Rockefeller University, New York, NY 10065, USA; Howard Hughes Medical Institute
| | - Anthony P West
- Division of Biology and Biological Engineering, California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125, USA
| | - Pamela J Bjorkman
- Division of Biology and Biological Engineering, California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125, USA; Howard Hughes Medical Institute.
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Roche J, Louis JM, Aniana A, Ghirlando R, Bax A. Complete dissociation of the HIV-1 gp41 ectodomain and membrane proximal regions upon phospholipid binding. JOURNAL OF BIOMOLECULAR NMR 2015; 61:235-48. [PMID: 25631354 PMCID: PMC4398632 DOI: 10.1007/s10858-015-9900-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2014] [Accepted: 01/17/2015] [Indexed: 05/22/2023]
Abstract
The envelope glycoprotein gp41 mediates the process of membrane fusion that enables entry of the HIV-1 virus into the host cell. Strong lipid affinity of the ectodomain suggests that its heptad repeat regions play an active role in destabilizing membranes by directly binding to the lipid bilayers and thereby lowering the free-energy barrier for membrane fusion. In such a model, immediately following the shedding of gp120, the N-heptad and C-heptad helices dissociate and melt into the host cell and viral membranes, respectively, pulling the destabilized membranes into juxtaposition, ready for fusion. Post-fusion, reaching the final 6-helix bundle (6 HB) conformation then involves competition between intermolecular interactions needed for formation of the symmetric 6 HB trimer and the membrane affinity of gp41's ectodomain, including its membrane-proximal regions. Our solution NMR study of the structural and dynamic properties of three constructs containing the ectodomain of gp41 with and without its membrane-proximal regions suggests that these segments do not form inter-helical interactions until the very late steps of the fusion process. Interactions between the polar termini of the heptad regions, which are not associating with the lipid surface, therefore may constitute the main driving force initiating formation of the final post-fusion states. The absence of significant intermolecular ectodomain interactions in the presence of dodecyl phosphocholine highlights the importance of trimerization of gp41's transmembrane helix to prevent complete dissociation of the trimer during the course of fusion.
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Affiliation(s)
- Julien Roche
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD, 20892, USA
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Metz GAS, Ng JWY, Kovalchuk I, Olson DM. Ancestral experience as a game changer in stress vulnerability and disease outcomes. Bioessays 2015; 37:602-11. [PMID: 25759985 DOI: 10.1002/bies.201400217] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Revised: 02/13/2015] [Accepted: 02/24/2015] [Indexed: 12/31/2022]
Abstract
Stress is one of the most powerful experiences to influence health and disease. Through epigenetic mechanisms, stress may generate a footprint that propagates to subsequent generations. Programming by prenatal stress or adverse experience in parents, grandparents, or earlier generations may thus be a critical determinant of lifetime health trajectories. Changes in regulation of microRNAs (miRNAs) by stress may enhance the vulnerability to certain pathogenic factors. This review explores the hypothesis that miRNAs represent stress-responsive elements in epigenetic regulation that are potentially heritable. Recent findings suggest that miRNAs are key players linking adverse early environments or ancestral stress with disease risk, thus they represent useful predictive disease biomarkers. Since miRNA signatures of disease are potentially heritable, big data management platforms will be vital to harness multi-generational information and capture succinct yet potent biomarkers capable of directing preventative treatments. This feature would offer a unique window of opportunity to advance personalized medicine.
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Affiliation(s)
- Gerlinde A S Metz
- Department of Neuroscience, Canadian Centre for Behavioural Neuroscience, University of Lethbridge, Lethbridge, AB, Canada
| | - Jane W Y Ng
- Department of Pediatrics, Faculty of Medicine, University of Calgary, Calgary, AB, Canada
| | - Igor Kovalchuk
- Department of Biological Sciences, University of Lethbridge, Lethbridge, AB, Canada
| | - David M Olson
- Departments of Obstetrics & Gynecology, Pediatrics and Physiology, University of Alberta, University of Alberta, Edmonton, AB, Canada
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Balance of cellular and humoral immunity determines the level of protection by HIV vaccines in rhesus macaque models of HIV infection. Proc Natl Acad Sci U S A 2015; 112:E992-9. [PMID: 25681373 DOI: 10.1073/pnas.1423669112] [Citation(s) in RCA: 104] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
A guiding principle for HIV vaccine design has been that cellular and humoral immunity work together to provide the strongest degree of efficacy. However, three efficacy trials of Ad5-vectored HIV vaccines showed no protection. Transmission was increased in two of the trials, suggesting that this vaccine strategy elicited CD4+ T-cell responses that provide more targets for infection, attenuating protection or increasing transmission. The degree to which this problem extends to other HIV vaccine candidates is not known. Here, we show that a gp120-CD4 chimeric subunit protein vaccine (full-length single chain) elicits heterologous protection against simian-human immunodeficiency virus (SHIV) or simian immunodeficiency virus (SIV) acquisition in three independent rhesus macaque repeated low-dose rectal challenge studies with SHIV162P3 or SIVmac251. Protection against acquisition was observed with multiple formulations and challenges. In each study, protection correlated with antibody-dependent cellular cytotoxicity specific for CD4-induced epitopes, provided that the concurrent antivaccine T-cell responses were minimal. Protection was lost in instances when T-cell responses were high or when the requisite antibody titers had declined. Our studies suggest that balance between a protective antibody response and antigen-specific T-cell activation is the critical element to vaccine-mediated protection against HIV. Achieving and sustaining such a balance, while enhancing antibody durability, is the major challenge for HIV vaccine development, regardless of the immunogen or vaccine formulation.
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50
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Richert L, Didier P, de Rocquigny H, Mély Y. Monitoring HIV-1 Protein Oligomerization by FLIM FRET Microscopy. SPRINGER SERIES IN CHEMICAL PHYSICS 2015. [DOI: 10.1007/978-3-319-14929-5_8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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