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Salgado M, Migueles SA, Yu XG, Martinez-Picado J. Exceptional, naturally occurring HIV-1 control: Insight into a functional cure. MED 2024:S2666-6340(24)00254-X. [PMID: 39013460 DOI: 10.1016/j.medj.2024.06.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Revised: 04/30/2024] [Accepted: 06/19/2024] [Indexed: 07/18/2024]
Abstract
Exceptional elite controllers represent an extremely rare group of people with HIV-1 (PWH) who exhibit spontaneous, high-level control of viral replication below the limits of detection in sensitive clinical monitoring assays and without disease progression in the absence of antiretroviral therapy for prolonged periods, frequently exceeding 25 years. Here, we discuss the different cases that have been reported in the scientific literature, their unique genetic, virological, and immunological characteristics, and their relevance as the best model for the functional cure of HIV-1.
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Affiliation(s)
- María Salgado
- IrsiCaixa Immunopathology Research Institute, 08916 Badalona, Spain; CIBERINFEC, 28029 Madrid, Spain; Germans Trias i Pujol Research Institute (IGTP), 08916 Badalona, Spain
| | - Stephen A Migueles
- Laboratory of Immunoregulation, Division of Intramural Research, and Collaborative Clinical Research Branch, Division of Clinical Research, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Xu G Yu
- Ragon Institute of MGH, MIT, and Harvard, Cambridge, MA, USA; Infectious Disease Division, Brigham and Women's Hospital, Boston, MA, USA
| | - Javier Martinez-Picado
- IrsiCaixa Immunopathology Research Institute, 08916 Badalona, Spain; CIBERINFEC, 28029 Madrid, Spain; University of Vic - Central University of Catalonia (UVic-UCC), 08500 Vic, Spain; Catalan Institution for Research and Advanced Studies (ICREA), 08010 Barcelona, Spain.
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Iwamoto Y, Ye AA, Shirazinejad C, Hurley JH, Drubin DG. Kinetic investigation reveals an HIV-1 Nef-dependent increase in AP-2 recruitment and productivity at endocytic sites. Mol Biol Cell 2024; 35:ar9. [PMID: 37938925 PMCID: PMC10881171 DOI: 10.1091/mbc.e23-04-0126] [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] [Received: 04/14/2023] [Revised: 10/24/2023] [Accepted: 11/02/2023] [Indexed: 11/10/2023] Open
Abstract
The HIV-1 accessory protein Nef hijacks clathrin adaptors to degrade or mislocalize host proteins involved in antiviral defenses. Here, using quantitative live-cell microscopy in genome-edited Jurkat cells, we investigate the impact of Nef on clathrin-mediated endocytosis (CME), a major pathway for membrane protein internalization in mammalian cells. Nef is recruited to CME sites on the plasma membrane, and this recruitment is associated with an increase in the recruitment and lifetime of the CME coat protein AP-2 and the late-arriving CME protein dynamin2. Furthermore, we find that CME sites that recruit Nef are more likely to recruit dynamin2 and transferrin, suggesting that Nef recruitment to CME sites promotes site maturation to ensure high efficiency in host protein downregulation. Implications of these observations for HIV-1 infection are discussed.
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Affiliation(s)
- Yuichiro Iwamoto
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720
| | - Anna A. Ye
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720
| | - Cyna Shirazinejad
- Biophysics Graduate Group, University of California, Berkeley, Berkeley, CA 94720
| | - James H. Hurley
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720
- California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, CA 94720
- Biophysics Graduate Group, University of California, Berkeley, Berkeley, CA 94720
- Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA 94720
| | - David G. Drubin
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720
- California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, CA 94720
- Biophysics Graduate Group, University of California, Berkeley, Berkeley, CA 94720
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Iwamoto Y, Ye A, Shirazinejad C, Hurley JH, Drubin DG. Kinetic investigation reveals an HIV-1 Nef-dependent increase in AP-2 recruitment and productivity at endocytic sites. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.18.537262. [PMID: 37131815 PMCID: PMC10153213 DOI: 10.1101/2023.04.18.537262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Lentiviruses express non-enzymatic accessory proteins whose function is to subvert cellular machinery in the infected host. The HIV-1 accessory protein Nef hijacks clathrin adaptors to degrade or mislocalize host proteins involved in antiviral defenses. Here, we investigate the interaction between Nef and clathrin-mediated endocytosis (CME), a major pathway for membrane protein internalization in mammalian cells, using quantitative live-cell microscopy in genome-edited Jurkat cells. Nef is recruited to CME sites on the plasma membrane, and this recruitment correlates with an increase in the recruitment and lifetime of CME coat protein AP-2 and late-arriving CME protein dynamin2. Furthermore, we find that CME sites that recruit Nef are more likely to recruit dynamin2, suggesting that Nef recruitment to CME sites promotes CME site maturation to ensure high efficiency in host protein downregulation.
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Affiliation(s)
- Yuichiro Iwamoto
- Department of Molecular and Cell Biology, University of California Berkeley; Berkeley CA 94720, USA
| | - Anna Ye
- Department of Molecular and Cell Biology, University of California Berkeley; Berkeley CA 94720, USA
| | - Cyna Shirazinejad
- Biophysics Graduate Group, University of California, Berkeley, Berkeley, CA 94720, USA
| | - James H Hurley
- Department of Molecular and Cell Biology, University of California Berkeley; Berkeley CA 94720, USA
- California Institute for Quantitative Biosciences, University of California, Berkeley, CA 94720, USA
- Biophysics Graduate Group, University of California, Berkeley, Berkeley, CA 94720, USA
- Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA 94720, USA
| | - David G Drubin
- Department of Molecular and Cell Biology, University of California Berkeley; Berkeley CA 94720, USA
- California Institute for Quantitative Biosciences, University of California, Berkeley, CA 94720, USA
- Biophysics Graduate Group, University of California, Berkeley, Berkeley, CA 94720, USA
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Immunologic Control of HIV-1: What Have We Learned and Can We Induce It? Curr HIV/AIDS Rep 2021; 18:211-220. [PMID: 33709324 DOI: 10.1007/s11904-021-00545-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/25/2021] [Indexed: 02/08/2023]
Abstract
PURPOSE OF REVIEW A large amount of data now exists on the virus-specific immune response associated with spontaneous or induced immunologic control of lentiviruses. This review focuses on how the current understanding of HIV-specific immunity might be leveraged into induction of immunologic control and what further research is needed to accomplish this goal. RECENT FINDINGS During chronic infection, the function most robustly associated with immunologic control of HIV-1 is CD8+ T cell cytotoxic capacity. This function has proven difficult to restore in HIV-specific CD8+ T cells of chronically infected progressors in vitro and in vivo. However, progress has been made in inducing an effective CD8+ T cell response prior to lentiviral infection in the macaque model and during acute lentiviral infection in non-human primates. Further study will likely accelerate the ability to induce an effective CD8+ T cell response as part of prophylactic or therapeutic strategies.
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Abstract
The Nef protein of HIV-1 and the unrelated glycoGag protein of a murine leukemia virus similarly prevent the uptake of antiviral host proteins called SERINC3 and SERINC5 into HIV-1 particles, which enhances their infectiousness. We now show that although both SERINC antagonists can in principle similarly enhance HIV-1 replication, glycoGag is unable to substitute for Nef in primary human cells and in a T cell line called MOLT-3. In MOLT-3 cells, Nef remained crucial for HIV-1 replication even in the absence of SERINC3 and SERINC5. The pronounced effect of Nef on HIV-1 spreading in MOLT-3 cells correlated with the ability of Nef to engage cellular endocytic machinery and to downregulate the HIV-1 receptor CD4 but nevertheless persisted in the absence of CD4 downregulation. Collectively, our results provide evidence for a potent novel restriction activity that affects even relatively SERINC-resistant HIV-1 isolates and is counteracted by Nef. It has recently emerged that HIV-1 Nef counteracts the antiviral host proteins SERINC3 and SERINC5. In particular, SERINC5 inhibits the infectivity of progeny virions when incorporated. SERINC3 and SERINC5 are also counteracted by the unrelated murine leukemia virus glycosylated Gag (glycoGag) protein, which possesses a potent Nef-like activity on HIV-1 infectivity. We now report that a minimal glycoGag termed glycoMA can fully substitute for Nef in promoting HIV-1 replication in Jurkat T lymphoid cells, indicating that Nef enhances replication in these cells mainly by counteracting SERINCs. In contrast, the SERINC antagonist glycoMA was unable to substitute for Nef in MOLT-3 T lymphoid cells, in which HIV-1 replication was highly dependent on Nef, and remained so even in the absence of SERINC3 and SERINC5. As in MOLT-3 cells, glycoMA was unable to substitute for Nef in stimulating HIV-1 replication in primary human cells. Although the ability of Nef mutants to promote HIV-1 replication in MOLT-3 cells correlated with the ability to engage endocytic machinery and to downregulate CD4, Nef nevertheless rescued virus replication under conditions where CD4 downregulation did not occur. Taken together, our observations raise the possibility that Nef triggers the endocytosis of a novel antiviral factor that is active against both laboratory-adapted and primary HIV-1 strains.
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Uhl J, Gujarathi S, Waheed AA, Gordon A, Freed EO, Gousset K. Myosin-X is essential to the intercellular spread of HIV-1 Nef through tunneling nanotubes. J Cell Commun Signal 2018; 13:209-224. [PMID: 30443895 DOI: 10.1007/s12079-018-0493-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Accepted: 11/01/2018] [Indexed: 12/18/2022] Open
Abstract
Tunneling nanotubes (TNTs) are intercellular structures that allow for the passage of vesicles, organelles, genomic material, pathogenic proteins and pathogens. The unconventional actin molecular motor protein Myosin-X (Myo10) is a known inducer of TNTs in neuronal cells, yet its role in other cell types has not been examined. The Nef HIV-1 accessory protein is critical for HIV-1 pathogenesis and can self-disseminate in culture via TNTs. Understanding its intercellular spreading mechanism could reveal ways to control its damaging effects during HIV-1 infection. Our goal in this study was to characterize the intercellular transport mechanism of Nef from macrophages to T cells. We demonstrate that Nef increases TNTs in a Myo10-dependent manner in macrophages and observed the transfer of Nef via TNTs from macrophages to T cells. To quantify this transfer mechanism, we established an indirect flow cytometry assay. Since Nef expression in T cells down-regulates the surface receptor CD4, we correlated the decrease in CD4 to the transfer of Nef between these cells. Thus, we co-cultured macrophages expressing varying levels of Nef with a T cell line expressing high levels of CD4 and quantified the changes in CD4 surface expression resulting from Nef transfer. We demonstrate that Nef transfer occurs via a cell-to-cell dependent mechanism that directly correlates with the presence of Myo10-dependent TNTs. Thus, we show that Nef can regulate Myo10 expression, thereby inducing TNT formation, resulting in its own transfer from macrophages to T cells. In addition, we demonstrate that up-regulation of Myo10 induced by Nef also occurs in human monocyte derived macrophages during HIV-1 infection.
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Affiliation(s)
- Jaime Uhl
- Biology Department, California State University Fresno, Fresno, 93740, USA
| | - Shivalee Gujarathi
- Biology Department, California State University Fresno, Fresno, 93740, USA
| | - Abdul A Waheed
- HIV Dynamics and Replication Program, National Cancer Institute-Frederick, Frederick, MD, 21702, USA
| | - Ana Gordon
- Biology Department, California State University Fresno, Fresno, 93740, USA
| | - Eric O Freed
- HIV Dynamics and Replication Program, National Cancer Institute-Frederick, Frederick, MD, 21702, USA
| | - Karine Gousset
- Biology Department, California State University Fresno, Fresno, 93740, USA.
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Martins MA, Tully DC, Shin YC, Gonzalez-Nieto L, Weisgrau KL, Bean DJ, Gadgil R, Gutman MJ, Domingues A, Maxwell HS, Magnani DM, Ricciardi M, Pedreño-Lopez N, Bailey V, Cruz MA, Lima NS, Bonaldo MC, Altman JD, Rakasz E, Capuano S, Reimann KA, Piatak M, Lifson JD, Desrosiers RC, Allen TM, Watkins DI. Rare Control of SIVmac239 Infection in a Vaccinated Rhesus Macaque. AIDS Res Hum Retroviruses 2017; 33:843-858. [PMID: 28503929 DOI: 10.1089/aid.2017.0046] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Effector memory T cell (TEM) responses display potent antiviral properties and have been linked to stringent control of simian immunodeficiency virus (SIV) replication. Since recurrent antigen stimulation drives the differentiation of CD8+ T cells toward the TEM phenotype, in this study we incorporated a persistent herpesviral vector into a heterologous prime/boost/boost vaccine approach to maximize the induction of TEM responses. This new regimen resulted in CD8+ TEM-biased responses in four rhesus macaques, three of which controlled viral replication to <1,000 viral RNA copies/ml of plasma for more than 6 months after infection with SIVmac239. Over the course of this study, we made a series of interesting observations in one of these successful controller animals. Indeed, in vivo elimination of CD8αβ+ T cells using a new CD8β-depleting antibody did not abrogate virologic control in this monkey. Only after its CD8α+ lymphocytes were depleted did SIV rebound, suggesting that CD8αα+ but not CD8αβ+ cells were controlling viral replication. By 2 weeks postinfection (PI), the only SIV sequences that could be detected in this animal harbored a small in-frame deletion in nef affecting six amino acids. Deep sequencing of the SIVmac239 challenge stock revealed no evidence of this polymorphism. However, sequencing of the rebound virus following CD8α depletion at week 38.4 PI again revealed only the six-amino acid deletion in nef. While any role for immunological pressure on the selection of this deleted variant remains uncertain, our data provide anecdotal evidence that control of SIV replication can be maintained without an intact CD8αβ+ T cell compartment.
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Affiliation(s)
| | - Damien C. Tully
- Ragon Institute of MGH, MIT and Harvard, Cambridge, Massachusetts
| | - Young C. Shin
- Department of Pathology, University of Miami, Miami, Florida
| | | | - Kim L. Weisgrau
- Wisconsin National Primate Research Center, University of Wisconsin—Madison, Madison, Wisconsin
| | - David J. Bean
- Ragon Institute of MGH, MIT and Harvard, Cambridge, Massachusetts
| | - Rujuta Gadgil
- Ragon Institute of MGH, MIT and Harvard, Cambridge, Massachusetts
| | | | - Aline Domingues
- Department of Pathology, University of Miami, Miami, Florida
| | | | | | | | | | - Varian Bailey
- Department of Pathology, University of Miami, Miami, Florida
| | - Michael A. Cruz
- Department of Pathology, University of Miami, Miami, Florida
| | - Noemia S. Lima
- Laboratório de Biologia Molecular de Flavivirus, Instituto Oswaldo Cruz–FIOCRUZ, Rio de Janeiro, Brazil
| | - Myrna C. Bonaldo
- Laboratório de Biologia Molecular de Flavivirus, Instituto Oswaldo Cruz–FIOCRUZ, Rio de Janeiro, Brazil
| | - John D. Altman
- Department of Microbiology and Immunology, Emory University, Atlanta, Georgia
| | - Eva Rakasz
- Wisconsin National Primate Research Center, University of Wisconsin—Madison, Madison, Wisconsin
| | - Saverio Capuano
- Wisconsin National Primate Research Center, University of Wisconsin—Madison, Madison, Wisconsin
| | - Keith A. Reimann
- MassBiologics, University of Massachusetts Medical School, Boston, Massachusetts
| | - Michael Piatak
- AIDS and Cancer Virus Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, Maryland
| | - Jeffrey D. Lifson
- AIDS and Cancer Virus Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, Maryland
| | | | - Todd M. Allen
- Ragon Institute of MGH, MIT and Harvard, Cambridge, Massachusetts
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Silver ZA, Watkins DI. The role of MHC class I gene products in SIV infection of macaques. Immunogenetics 2017; 69:511-519. [PMID: 28695289 PMCID: PMC5537376 DOI: 10.1007/s00251-017-0997-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2017] [Accepted: 04/30/2017] [Indexed: 01/27/2023]
Abstract
Human immunodeficiency virus (HIV) remains among the most significant public health threats worldwide. Despite three decades of research following the discovery of HIV, a preventive vaccine remains elusive. The study of HIV elite controllers has been crucial to elaborate the genetic and immunologic determinants that underlie control of HIV replication. Coordinated studies of elite control in humans have, however, been limited by variability among infecting viral strains, host genotype, and the uncertainty of the timing and route of infection. In this review, we discuss the role of nonhuman primate (NHP) models for the elucidation of the immunologic correlates that underlie control of AIDS virus replication. We discuss the importance of major histocompatibility complex class I (MHC-I) alleles in activating CD8+ T-cell populations that promote control of both HIV and simian immunodeficiency virus (SIV) replication. Provocatively, we make the argument that T-cell subsets recognizing the HIV/SIV viral infectivity factor (Vif) protein may be crucial for control of viral replication. We hope that this review demonstrates how an in-depth understanding of the MHC-I gene products associated with elite control of HIV/SIV, and the epitopes that they present, can provide researchers with a glimpse into the protective immune responses that underlie AIDS nonprogression.
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Affiliation(s)
- Zachary A Silver
- Medical Scientist Training Program, University of Miami Miller School of Medicine, Miami, FL, USA. .,Department of Pathology, University of Miami Miller School of Medicine, Miami, FL, USA.
| | - David I Watkins
- Department of Pathology, University of Miami Miller School of Medicine, Miami, FL, USA
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A Highly Conserved Residue in HIV-1 Nef Alpha Helix 2 Modulates Protein Expression. mSphere 2016; 1:mSphere00288-16. [PMID: 27840851 PMCID: PMC5103047 DOI: 10.1128/msphere.00288-16] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Accepted: 10/21/2016] [Indexed: 01/22/2023] Open
Abstract
The HIV-1 Nef protein has been established as a key pathogenic determinant of HIV/AIDS, but there is little knowledge of how the extensive genetic diversity of HIV-1 affects Nef function. Upon compiling a set of subtype-specific reference strains, we identified a subtype C reference strain, C.BR92025, that contained natural polymorphisms at otherwise highly conserved residues 13, 84, and 92. Interestingly, strain C.BR92025 Nef displayed impaired Nef function and had decreased protein expression. We have demonstrated that strain C.BR92025 Nef has a higher rate of protein turnover than highly expressed Nef proteins and that this higher rate of protein turnover is due to an alanine-to-valine substitution at Nef residue 84. These findings highlight residue A84 as a major determinant of HIV-1 Nef expression. Extensive genetic diversity is a defining characteristic of human immunodeficiency virus type 1 (HIV-1) and poses a significant barrier to the development of an effective vaccine. To better understand the impact of this genetic diversity on the HIV-1 pathogenic factor Nef, we compiled a panel of reference strains from the NIH Los Alamos HIV Database. Initial sequence analysis identified point mutations at Nef residues 13, 84, and 92 in subtype C reference strain C.BR92025 from Brazil. Functional analysis revealed impaired major histocompatibility complex class I and CD4 downregulation of strain C.BR92025 Nef, which corresponded to decreased protein expression. Metabolic labeling demonstrated that strain C.BR92025 Nef has a greater rate of protein turnover than subtype B reference strain B.JRFL that, on the basis of mutational analysis, is related to Nef residue A84. An alanine-to-valine substitution at position 84, located in alpha helix 2 of Nef, was sufficient to alter the rate of turnover of an otherwise highly expressed Nef protein. In conclusion, these findings highlight HIV-1 Nef residue A84 as a major determinant of protein expression that may offer an additional avenue to disrupt or mediate the effects of this key HIV-1 pathogenic factor. IMPORTANCE The HIV-1 Nef protein has been established as a key pathogenic determinant of HIV/AIDS, but there is little knowledge of how the extensive genetic diversity of HIV-1 affects Nef function. Upon compiling a set of subtype-specific reference strains, we identified a subtype C reference strain, C.BR92025, that contained natural polymorphisms at otherwise highly conserved residues 13, 84, and 92. Interestingly, strain C.BR92025 Nef displayed impaired Nef function and had decreased protein expression. We have demonstrated that strain C.BR92025 Nef has a higher rate of protein turnover than highly expressed Nef proteins and that this higher rate of protein turnover is due to an alanine-to-valine substitution at Nef residue 84. These findings highlight residue A84 as a major determinant of HIV-1 Nef expression.
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Success and failure of the cellular immune response against HIV-1. Nat Immunol 2015; 16:563-70. [PMID: 25988888 DOI: 10.1038/ni.3161] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Accepted: 03/27/2015] [Indexed: 02/07/2023]
Abstract
The cellular immune response to HIV-1 has now been studied in extraordinary detail. A very large body of data provides the most likely reasons that the HIV-specific cellular immune response succeeds in a small number of people but fails in most. Understanding the success and failure of the HIV-specific cellular immune response has implications that extend not only to immunotherapies and vaccines for HIV-1 but also to the cellular immune response in other disease states. This Review focuses on the mechanisms that are most likely responsible for durable and potent immunologic control of HIV-1. Although we now have a detailed picture of the cellular immune responses to HIV-1, important questions remain regarding the nature of these responses and how they arise.
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Tracking the Emergence of Host-Specific Simian Immunodeficiency Virus env and nef Populations Reveals nef Early Adaptation and Convergent Evolution in Brain of Naturally Progressing Rhesus Macaques. J Virol 2015; 89:8484-96. [PMID: 26041280 DOI: 10.1128/jvi.01010-15] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Accepted: 05/27/2015] [Indexed: 01/30/2023] Open
Abstract
UNLABELLED While a clear understanding of the events leading to successful establishment of host-specific viral populations and productive infection in the central nervous system (CNS) has not yet been reached, the simian immunodeficiency virus (SIV)-infected rhesus macaque provides a powerful model for the study of human immunodeficiency virus (HIV) intrahost evolution and neuropathogenesis. The evolution of the gp120 and nef genes, which encode two key proteins required for the establishment and maintenance of infection, was assessed in macaques that were intravenously inoculated with the same viral swarm and allowed to naturally progress to simian AIDS and potential SIV-associated encephalitis (SIVE). Longitudinal plasma samples and immune markers were monitored until terminal illness. Single-genome sequencing was employed to amplify full-length env through nef transcripts from plasma over time and from brain tissues at necropsy. nef sequences diverged from the founder virus faster than gp120 diverged. Host-specific sequence populations were detected in nef (~92 days) before they were detected in gp120 (~182 days). At necropsy, similar brain nef sequences were found in different macaques, indicating convergent evolution, while gp120 brain sequences remained largely host specific. Molecular clock and selection analyses showed weaker clock-like behavior and stronger selection pressure in nef than in gp120, with the strongest nef selection in the macaque with SIVE. Rapid nef diversification, occurring prior to gp120 diversification, indicates that early adaptation of nef in the new host is essential for successful infection. Moreover, the convergent evolution of nef sequences in the CNS suggests a significant role for nef in establishing neurotropic strains. IMPORTANCE The SIV-infected rhesus macaque model closely resembles HIV-1 immunopathogenesis, neuropathogenesis, and disease progression in humans. Macaques were intravenously infected with identical viral swarms to investigate evolutionary patterns in the gp120 and nef genes leading to the emergence of host-specific viral populations and potentially linked to disease progression. Although each macaque exhibited unique immune profiles, macaque-specific nef sequences evolving under selection were consistently detected in plasma samples at 3 months postinfection, significantly earlier than in gp120 macaque-specific sequences. On the other hand, nef sequences in brain tissues, collected at necropsy of two animals with detectable infection in the central nervous system (CNS), revealed convergent evolution. The results not only indicate that early adaptation of nef in the new host may be essential for successful infection, but also suggest that specific nef variants may be required for SIV to efficiently invade CNS macrophages and/or enhance macrophage migration, resulting in HIV neuropathology.
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de Carvalho JV, de Castro RO, da Silva EZM, Silveira PP, da Silva-Januário ME, Arruda E, Jamur MC, Oliver C, Aguiar RS, daSilva LLP. Nef neutralizes the ability of exosomes from CD4+ T cells to act as decoys during HIV-1 infection. PLoS One 2014; 9:e113691. [PMID: 25423108 PMCID: PMC4244142 DOI: 10.1371/journal.pone.0113691] [Citation(s) in RCA: 82] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Accepted: 10/27/2014] [Indexed: 01/09/2023] Open
Abstract
Nef is an HIV-1 accessory protein that promotes viral replication and pathogenesis. A key function of Nef is to ensure sustained depletion of CD4 and MHC-I molecules in infected cells by inducing targeting of these proteins to multivesicular bodies (MVBs), and ultimately to lysosomes for degradation. Nef also affects cellular secretory routes promoting its own secretion via exosomes. To better understand the effects of Nef on the exocytic pathway, we investigated whether this viral factor modifies the composition of exosomes released by T lymphocytes. We showed that both CD4 and MHC-I molecules are secreted in exosomes from T cells and that the expression of Nef reduces the amount of these proteins in exosomes. To investigate the functional role for this novel activity of Nef, we performed in vitro HIV-1 infection assays in the presence of distinct populations of exosomes. We demonstrated that exosomes released by CD4+ T cells, but not CD4− T cells, efficiently inhibit HIV-1 infection in vitro. Because CD4 is the main receptor for HIV-1 infection, these results suggest that CD4 molecules displayed on the surface of exosomes can bind to envelope proteins of HIV-1 hindering virus interaction with target cells and infection. Importantly, CD4-depleted exosomes released by CD4+ T cells expressing Nef have a reduced capacity to inhibit HIV-1 infection in vitro. These results provide evidence that Nef promotes HIV-1 infection by reducing the expression of CD4 in exosomes from infected cells, besides the original role of Nef in reducing the CD4 levels at the cell surface.
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Affiliation(s)
- Julianne V. de Carvalho
- Department of Cell and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Rodrigo O. de Castro
- Department of Cell and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Elaine Z. M. da Silva
- Department of Cell and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Paola P. Silveira
- Molecular Virology Laboratory, Department of Genetics, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Mara E. da Silva-Januário
- Department of Cell and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Eurico Arruda
- Department of Cell and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Maria C. Jamur
- Department of Cell and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Constance Oliver
- Department of Cell and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Renato S. Aguiar
- Molecular Virology Laboratory, Department of Genetics, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Luis L. P. daSilva
- Department of Cell and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
- * E-mail:
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Amorim NA, da Silva EML, de Castro RO, da Silva-Januário ME, Mendonça LM, Bonifacino JS, da Costa LJ, daSilva LLP. Interaction of HIV-1 Nef protein with the host protein Alix promotes lysosomal targeting of CD4 receptor. J Biol Chem 2014; 289:27744-56. [PMID: 25118280 DOI: 10.1074/jbc.m114.560193] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Nef is an accessory protein of human immunodeficiency viruses that promotes viral replication and progression to AIDS through interference with various host trafficking and signaling pathways. A key function of Nef is the down-regulation of the coreceptor CD4 from the surface of the host cells. Nef-induced CD4 down-regulation involves at least two independent steps as follows: acceleration of CD4 endocytosis by a clathrin/AP-2-dependent pathway and targeting of internalized CD4 to multivesicular bodies (MVBs) for eventual degradation in lysosomes. In a previous work, we found that CD4 targeting to the MVB pathway was independent of CD4 ubiquitination. Here, we report that this targeting depends on a direct interaction of Nef with Alix/AIP1, a protein associated with the endosomal sorting complexes required for transport (ESCRT) machinery that assists with cargo recruitment and intraluminal vesicle formation in MVBs. We show that Nef interacts with both the Bro1 and V domains of Alix. Depletion of Alix or overexpression of the Alix V domain impairs lysosomal degradation of CD4 induced by Nef. In contrast, the V domain overexpression does not prevent cell surface removal of CD4 by Nef or protein targeting to the canonical ubiquitination-dependent MVB pathway. We also show that the Nef-Alix interaction occurs in late endosomes that are enriched in internalized CD4. Together, our results indicate that Alix functions as an adaptor for the ESCRT-dependent, ubiquitin-independent targeting of CD4 to the MVB pathway induced by Nef.
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Affiliation(s)
- Nathaly A Amorim
- From the Department of Cell and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, SP 14049-900, Brazil
| | - Eulália M L da Silva
- From the Department of Cell and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, SP 14049-900, Brazil
| | - Rodrigo O de Castro
- From the Department of Cell and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, SP 14049-900, Brazil
| | - Mara E da Silva-Januário
- From the Department of Cell and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, SP 14049-900, Brazil
| | - Luiza M Mendonça
- the Department of Virology, Institute of Microbiology Paulo de Góes, Federal University of Rio de Janeiro, Rio de Janeiro, RJ 21941-590, Brazil, and
| | - Juan S Bonifacino
- the Cell Biology and Metabolism Program, Eunice Kennedy Shriver NICHD, National Institutes of Health, Bethesda, Maryland 20892
| | - Luciana J da Costa
- the Department of Virology, Institute of Microbiology Paulo de Góes, Federal University of Rio de Janeiro, Rio de Janeiro, RJ 21941-590, Brazil, and
| | - Luis L P daSilva
- From the Department of Cell and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, SP 14049-900, Brazil,
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15
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Association of single nucleotide polymorphisms in the lens epithelium-derived growth factor (LEDGF/p75) with HIV-1 infection outcomes in Brazilian HIV-1+ individuals. PLoS One 2014; 9:e101780. [PMID: 25047784 PMCID: PMC4105638 DOI: 10.1371/journal.pone.0101780] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Accepted: 06/11/2014] [Indexed: 12/12/2022] Open
Abstract
The lens epithelium-derived growth factor p75 (LEDGF/p75), coded by the PSIP1 gene, is an important host co-factor that interacts with HIV-1 integrase to target integration of viral cDNA into active genes. The aim of this study was to investigate the association of SNPs in the PSIP1 gene with disease outcome in HIV-1 infected patients. We performed a genetic association study in a cohort of 171 HIV-1 seropositive Brazilian individuals classified as rapid progressors (RP, n = 69), typical progressors (TP, n = 79) and long-term nonprogressors (LTNP, n = 23). The exonic SNP rs61744944 and 9 tag SNPs were genotyped. A group of 192 healthy subjects was analyzed to determine the frequency of SNPs and haplotypes in the general population. Linkage disequilibrium (LD) analyses indicated that the SNPs analyzed were not in high LD (r2<0.8). Logistic regression models suggested that patients carrying the T allele rs61744944 (472L) were more likely to develop a LTNP phenotype (OR = 4.98; p = 0.05) as compared to TP group. The same trend was observed when LTNPs were compared to the RP group (OR = 3.26). Results of haplotype analyses reinforced this association, since the OR values obtained for the haplotype carrying allele T at rs61744944 also reflected an association with LTNP status (OR = 6.05; p = 0.08 and OR = 3.44; p = 0.12 for comparisons to TP and RP, respectively). The rare missense variations Ile436Ser and Thr473Ile were not identified in the patients enrolled in this study. Gene expression analyses showed lower LEDGF/p75 mRNA levels in peripheral blood mononuclear cells obtained from HIV-1 infected individuals. However, these levels were not influenced by any of the SNPs investigated. In spite of the limited number of LTNPs, these data suggest that the PSIP1 gene could be associated with the outcome of HIV-1 infection. Further analyses of this gene may guide the identification of causative variants to help predict disease course.
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Tarafdar S, Poe JA, Smithgall TE. The accessory factor Nef links HIV-1 to Tec/Btk kinases in an Src homology 3 domain-dependent manner. J Biol Chem 2014; 289:15718-28. [PMID: 24722985 DOI: 10.1074/jbc.m114.572099] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The HIV-1 Nef virulence factor interacts with multiple host cell-signaling proteins. Nef binds to the Src homology 3 domains of Src family kinases, resulting in kinase activation important for viral infectivity, replication, and MHC-I down-regulation. Itk and other Tec family kinases are also present in HIV target cells, and Itk has been linked to HIV-1 infectivity and replication. However, the molecular mechanism linking Itk to HIV-1 is unknown. In this study, we explored the interaction of Nef with Tec family kinases using a cell-based bimolecular fluorescence complementation assay. In this approach, interaction of Nef with a partner kinase juxtaposes nonfluorescent YFP fragments fused to the C terminus of each protein, resulting in YFP complementation and a bright fluorescent signal. Using bimolecular fluorescence complementation, we observed that Nef interacts with the Tec family members Bmx, Btk, and Itk but not Tec or Txk. Interaction with Nef occurs through the kinase Src homology 3 domains and localizes to the plasma membrane. Allelic variants of Nef from all major HIV-1 subtypes interacted strongly with Itk in this assay, demonstrating the highly conserved nature of this interaction. A selective small molecule inhibitor of Itk kinase activity (BMS-509744) potently blocked wild-type HIV-1 infectivity and replication, but not that of a Nef-defective mutant. Nef induced constitutive Itk activation in transfected cells that was sensitive to inhibitor treatment. Taken together, these results provide the first evidence that Nef interacts with cytoplasmic tyrosine kinases of the Tec family and suggest that Nef provides a mechanistic link between HIV-1 and Itk signaling in the viral life cycle.
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Affiliation(s)
- Sreya Tarafdar
- From the Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15219 and the Department of Infectious Diseases and Microbiology, University of Pittsburgh Graduate School of Public Health, Pittsburgh, Pennsylvania 15261
| | - Jerrod A Poe
- From the Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15219 and
| | - Thomas E Smithgall
- From the Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15219 and
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17
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Association of the HLA-B*52 allele with non-progression to AIDS in Brazilian HIV-1-infected individuals. Genes Immun 2014; 15:256-62. [PMID: 24718028 DOI: 10.1038/gene.2014.14] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2013] [Revised: 02/26/2014] [Accepted: 02/28/2014] [Indexed: 12/25/2022]
Abstract
Several human leukocyte antigen (HLA) class I alleles are associated with the susceptibility to human immunodeficiency virus-1 (HIV-1) infection and/or AIDS progression. Of these, the HLA-B alleles are considered the strongest genetic determinant of disease outcome. We evaluated the influence of the HLA-B alleles on AIDS progression among HIV-1-positive individuals from Rio de Janeiro, Brazil, who were categorized as rapid progressors (RPs), typical progressors (TPs) or long-term non-progressors (LTNPs). In this study, significant differences in HLA-B allele frequencies were observed among the three progression groups for the B*48, B*49 and B*52 alleles. After controlling for other factors associated with AIDS progression, the presence of the B*52 allele was shown to be a significant protective factor (hazard ratio (HR) 0.49 (95% confidence interval (CI) 0.27-0.90) P<0.03). Although no direct association was observed between the presence of the B*27 or B*57 allele and the LTNP profile compared with the TP or RP groups, the adjusted model confirmed that these alleles are protective factors against AIDS progression (HR 0.62 (95% CI 0.38-0.99) P<0.05), as previously described. These data corroborate the existence of significant differences in HLA-B allele frequencies among the distinct AIDS progression profiles and further elucidate the role of HLA alleles in the outcome of HIV infections in diverse populations.
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Salgado M, Gandhi S, Buckheit RW, Berkenblit GV, Blankson JN. Evolution of an attenuated HIV-1 isolate in an elite suppressor. AIDS Res Hum Retroviruses 2014; 30:284-8. [PMID: 24117037 DOI: 10.1089/aid.2013.0229] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Elite controllers or suppressors (ES) control viral replication without antiretroviral therapy. While many ES are infected with replication-competent virus, others have evidence of infection with attenuated isolates. Here we report a case of an ES infected with an HIV-1 isolate that contained a 38-base pair deletion in nef that led to a reading frame shift and a premature stop codon. Interestingly, clones amplified from plasma or cultured from CD4(+) T cells between 2006 and 2008 contained one of two separate compensatory deletions that restored the reading frame. A new insertion generated by duplication of adjacent sequences was found in isolates obtained in 2010 and this evolution was accompanied by the development of low level viremia. This article provides evidence of the evolution of an attenuated HIV-1 isolate toward greater virulence in an elite suppressor.
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Affiliation(s)
- Maria Salgado
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland
- AIDS Research Institute IrsiCaixa, Institut d'Investigació en Ciències de la Salut Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain
| | - Shiv Gandhi
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Robert W. Buckheit
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Gail V. Berkenblit
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Joel N. Blankson
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland
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Iyer PC, Zhao J, Emert-Sedlak LA, Moore KK, Smithgall TE, Day BW. Synthesis and structure-activity analysis of diphenylpyrazolodiazene inhibitors of the HIV-1 Nef virulence factor. Bioorg Med Chem Lett 2014; 24:1702-6. [PMID: 24650642 DOI: 10.1016/j.bmcl.2014.02.045] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2014] [Revised: 02/12/2014] [Accepted: 02/18/2014] [Indexed: 10/25/2022]
Abstract
HIV-1 Nef is a critical AIDS progression factor yet underexplored target for antiretroviral drug discovery. A recent high-throughput screen for pharmacological inhibitors of Nef-dependent Src-family kinase activation identified a diphenylpyrazolodiazene hit compound with submicromolar potency in HIV-1 replication assays against a broad range of primary Nef variants. This compound, known as 'B9', binds directly to Nef and inhibits its dimerization in cells as a possible mechanism of action. Here were synthesized a diverse set of B9 analogs and identified structural features essential to antiretroviral activity. Chemical modifications to each of the three rings present in the parent compound were identified that did not compromise antiviral action. These analogs will guide the development of next-generation compounds with appropriate pharmacological profiles for assessment of antiretroviral activity in vivo.
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Affiliation(s)
- Prema C Iyer
- Department of Pharmaceutical Sciences, University of Pittsburgh School of Pharmacy, Pittsburgh, PA 15261, USA; University of Pittsburgh Drug Discovery Institute, Pittsburgh, PA 15261, USA
| | - Jielu Zhao
- Department of Pharmaceutical Sciences, University of Pittsburgh School of Pharmacy, Pittsburgh, PA 15261, USA; University of Pittsburgh Drug Discovery Institute, Pittsburgh, PA 15261, USA
| | - Lori A Emert-Sedlak
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Bridgeside Point II, Suite 523, 450 Technology Drive, Pittsburgh, PA 15219, USA
| | - Kerry K Moore
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Thomas E Smithgall
- University of Pittsburgh Drug Discovery Institute, Pittsburgh, PA 15261, USA; Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Bridgeside Point II, Suite 523, 450 Technology Drive, Pittsburgh, PA 15219, USA.
| | - Billy W Day
- Department of Pharmaceutical Sciences, University of Pittsburgh School of Pharmacy, Pittsburgh, PA 15261, USA; University of Pittsburgh Drug Discovery Institute, Pittsburgh, PA 15261, USA; Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260, USA
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20
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The Nef-like effect of murine leukemia virus glycosylated gag on HIV-1 infectivity is mediated by its cytoplasmic domain and depends on the AP-2 adaptor complex. J Virol 2014; 88:3443-54. [PMID: 24403584 DOI: 10.1128/jvi.01933-13] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
UNLABELLED Human immunodeficiency virus type 1 (HIV-1) Nef enhances the infectivity of progeny virions. However, Nef is dispensable for the production of HIV-1 virions of optimal infectivity if the producer cells are superinfected with certain gammaretroviruses. In the case of the ecotropic Moloney murine leukemia virus (M-MLV), the Nef-like effect is mediated by the glycosylated Gag (glycoGag) protein. We now show that the N-terminal intracellular domain of the type II transmembrane protein glycoGag is responsible for its effect on HIV-1 infectivity. In the context of a fully active minimal M-MLV glycoGag construct, truncations of the cytoplasmic domain led to a near total loss of activity. Furthermore, the cytoplasmic domain of M-MLV glycoGag was fully sufficient to transfer the activity to an unrelated type II transmembrane protein. Although the intracellular region of glycoGag is relatively poorly conserved even among ecotropic and xenotropic MLVs, it was also fully sufficient for the rescue of nef-deficient HIV-1 when derived from a xenotropic virus. A mutagenic analysis showed that only a core region of the intracellular domain that exhibits at least some conservation between murine and feline leukemia viruses is crucial for activity. In particular, a conserved YXXL motif in the center of this core region was critical. In addition, expression of the μ2 subunit of the AP-2 adaptor complex in virus producer cells was essential for activity. We conclude that the ability to enhance HIV-1 infectivity is a conserved property of the MLV glycoGag cytoplasmic domain and involves AP-2-mediated endocytosis. IMPORTANCE The Nef protein of HIV-1 and the entirely unrelated glycosylated Gag (glycoGag) protein of a murine leukemia virus (MLV) similarly enhance the infectiousness of HIV-1 particles by an unknown mechanism. MLV glycoGag is an alternative version of the structural viral Gag protein with an extra upstream region that provides a cytosolic domain and a plasma membrane anchor. We now show for the first time that the cytosolic domain of MLV glycoGag contains all the information needed to enhance HIV-1 infectivity and that this function of the cytosolic domain is conserved despite limited sequence conservation. Within the cytosolic domain, a motif that resembles a cellular sorting signal is critical for activity. Furthermore, the enhancement of HIV-1 infectivity depends on an endocytic cellular protein that is known to interact with such sorting signals. Together, our findings implicate the endocytic machinery in the enhancement of HIV-1 infectivity by MLV glycoGag.
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HLA-B*57 elite suppressor and chronic progressor HIV-1 isolates replicate vigorously and cause CD4+ T cell depletion in humanized BLT mice. J Virol 2014; 88:3340-52. [PMID: 24390323 DOI: 10.1128/jvi.03380-13] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Elite controllers or suppressors (ES) are HIV-1-infected patients who maintain undetectable viral loads without antiretroviral therapy. The mechanism of control remains unclear, but the HLA-B*57 allele is overrepresented in cohorts of these patients. However, many HLA-B*57 patients develop progressive disease, and some studies have suggested that infection with defective viruses may be the cause of the lack of high levels of virus replication and disease progression in ES. We therefore performed a comprehensive comparative in vivo and in vitro characterization of viruses isolated from well-defined ES. For this purpose, we first performed full-genome sequence analysis and in vitro fitness assays on replication-competent isolates from HLA-B*57 ES and HLA-B*57 chronic progressors (CPs). Under our experimental conditions, we found that isolates from ES and CPs can replicate in vitro. However, since inherently these assays involve the use of unnaturally in vitro-activated cells, we also investigated the replication competence and pathogenic potential of these HIV isolates in vivo using humanized BLT mice. The results from these analyses demonstrate that virus isolates from ES are fully replication competent in vivo and can induce peripheral and systemic CD4 T cell depletion. These results provide the first direct in vivo evidence that viral fitness does not likely determine clinical outcome in HLA-B*57 patients and that elite suppressors can control replication-competent, fully pathogenic viruses. A better understanding of the immunological bases of viral suppression in ES will serve to inform novel approaches to preventive and therapeutic HIV vaccine design. IMPORTANCE Elite suppressors are HIV-1-infected patients who have undetectable levels of viremia despite not being on antiviral drugs. One of the most fundamental questions about this phenomenon involves the mechanism of control. To address this question, we isolated virus from elite suppressors and from HIV-1-infected patients who have the usual progressive disease course. We compared how well the isolates from the two groups of patients replicated in culture and in humanized mice. Our results suggest that elite suppressors are capable of controlling HIV-1 due to the possession of unique host factors rather than infection with defective virus.
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22
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Poe JA, Vollmer L, Vogt A, Smithgall TE. Development and validation of a high-content bimolecular fluorescence complementation assay for small-molecule inhibitors of HIV-1 Nef dimerization. ACTA ACUST UNITED AC 2013; 19:556-65. [PMID: 24282155 DOI: 10.1177/1087057113513640] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Nef is a human immunodeficiency virus 1 (HIV-1) accessory factor essential for viral pathogenesis and AIDS progression. Many Nef functions require dimerization, and small molecules that block Nef dimerization may represent antiretroviral drug leads. Here we describe a cell-based assay for Nef dimerization inhibitors based on bimolecular fluorescence complementation (BiFC). Nef was fused to nonfluorescent, complementary fragments of yellow fluorescent protein (YFP) and coexpressed in the same cell population. Dimerization of Nef resulted in juxtaposition of the YFP fragments and reconstitution of the fluorophore. For automation, the Nef-YFP fusion proteins plus a monomeric red fluorescent protein (mRFP) reporter were expressed from a single vector, separated by picornavirus "2A" linker peptides to permit equivalent translation of all three proteins. Validation studies revealed a critical role for gating on the mRFP-positive subpopulation of transfected cells, as well as use of the mRFP signal to normalize the Nef-BiFC signal. Nef-BiFC/mRFP ratios resulting from cells expressing wild-type versus dimerization-defective Nef were very clearly separated, with Z factors consistently in the 0.6 to 0.7 range. A fully automated pilot screen of the National Cancer Institute Diversity Set III identified several hit compounds that reproducibly blocked Nef dimerization in the low micromolar range. This BiFC-based assay has the potential to identify cell-active small molecules that directly interfere with Nef dimerization and function.
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Affiliation(s)
- Jerrod A Poe
- 1Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
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Abstract
Untreated HIV-1 infection typically progresses to AIDS within 10 years, but less than 1% of infected individuals remain healthy and have normal CD4(+) T cell counts and undetectable viral loads; some individuals have remained this way for 35 years and counting. Through a combination of large population studies of cohorts of these 'HIV-1 controllers' and detailed studies of individual patients, a heterogeneous picture has emerged regarding the basis for this remarkable resistance to AIDS progression. In this Review, we highlight the host genetic factors, the viral genetic factors and the immunological factors that are associated with the controller phenotype, we discuss emerging methodological approaches that could facilitate a better understanding of spontaneous HIV-1 immune control in the future, and we delineate implications for a 'functional cure' of HIV-1 infection.
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Affiliation(s)
- Bruce D Walker
- Ragon Institute of MGH, MIT and Harvard, Massachusetts General Hospital, Cambridge, Massachusetts 02139, USA.
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Cho YK, Jung Y, Sung H, Joo CH. Frequent Genetic Defects in the HIV-1 5' LTR/gag Gene in Hemophiliacs Treated with Korean Red Ginseng: Decreased Detection of Genetic Defects by Highly Active Antiretroviral Therapy. J Ginseng Res 2013; 35:413-20. [PMID: 23717086 PMCID: PMC3659557 DOI: 10.5142/jgr.2011.35.4.413] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2011] [Revised: 08/11/2011] [Accepted: 08/11/2011] [Indexed: 11/18/2022] Open
Abstract
We investigated whether Korean red ginseng (KRG) and highly active antiretroviral therapy (HAART) affect the frequency of gross deletion in 5’LTR/gag in 20 hemophiliacs. This study is a prospective study in 20 hemophiliacs who were infected with Korean subclade B of HIV-1 from two cash-paid plasma donors in 1990. Over a 13-year period, we obtained 436 amplicons of 5’LTR/gag genes by nested polymerase chain reaction using 147 peripheral blood mononuclear cells. Of the 436 amplicons, 92 (21.1%) showed gross deletion in 5’LTR/gag. Despite of a 2.3-fold higher monthly dose of KRG intake, the frequency of gross deletion in 5’LTR/gag (16.4%) was significantly decreased during HAART compared with 28.1% prior to HAART (p<0.01). Gross deletion in 5’LTR/gag was 10% more detected on KRG-therapy than prior to KRG-therapy (p<0.05). In addition, we also obtained 28 amplicons containing premature stop codon or isoleucine at initiation codon of 254 amplicons sequenced on KRG intake (7.5%) or HAART (13.6%) compared with 0% before KRG intake. These findings indicate that high frequency of gross deletion in 5’LTR/gag and genetic defects prior to HAART are significantly associated with KRG intake and the detection of gross deletion in 5’LTR/gag is decreased by HAART.
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Affiliation(s)
- Young-Keol Cho
- Department of Microbiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul 138-076, Korea
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25
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Buckheit III RW, Salgado M, Martins KO, Blankson JN. The implications of viral reservoirs on the elite control of HIV-1 infection. Cell Mol Life Sci 2013; 70:1009-19. [PMID: 22864624 PMCID: PMC11113402 DOI: 10.1007/s00018-012-1101-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2012] [Revised: 07/02/2012] [Accepted: 07/17/2012] [Indexed: 01/24/2023]
Abstract
The mechanisms by which a small percentage of HIV-1 infected individuals known as elite suppressors or controllers are able to control viral replication are not fully understood. Early cases of viremic control were attributed to infection with defective virus, but subsequent work has demonstrated that infection with a defective virus is not the exclusive cause of control. Replication-competent virus has been isolated from patients who control viral replication, and studies have demonstrated that evolution occurs in plasma virus but not in virus isolates from the latent reservoir. Additionally, transmission pair studies have demonstrated that patients infected with similar viruses can have dramatically different outcomes of infection. An increased understanding of the viral factors associated with control is important to understand the interplay between viral replication and host control, and has implications for the design of an effective therapeutic vaccine that can lead to a functional cure of HIV-1 infection.
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Affiliation(s)
- Robert W. Buckheit III
- Department of Medicine, Johns Hopkins University School of Medicine, 733 N. Broadway, BRB 880, Baltimore, MD 21205 USA
| | - Maria Salgado
- Department of Medicine, Johns Hopkins University School of Medicine, 733 N. Broadway, BRB 880, Baltimore, MD 21205 USA
- Institut de Recerca de La SIDA (IrsiCaixa), Hospital Universitari Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain
| | - Karen O. Martins
- Department of Integrated Toxicology, USAMRIID, Frederick, MD 21702 USA
| | - Joel N. Blankson
- Department of Medicine, Johns Hopkins University School of Medicine, 733 N. Broadway, BRB 880, Baltimore, MD 21205 USA
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27
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Corró G, Rocco CA, De Candia C, Catano G, Turk G, Mangano A, Aulicino PC, Bologna R, Sen L. Genetic and functional analysis of HIV type 1 nef gene derived from long-term nonprogressor children: association of attenuated variants with slow progression to pediatric AIDS. AIDS Res Hum Retroviruses 2012; 28:1617-26. [PMID: 22583022 DOI: 10.1089/aid.2012.0020] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Among persons infected by HIV-1, the rate of progression to AIDS is multifactorial being affected by host and viral factors, including the HIV-encoded negative factor (Nef). Our aim was to define whether variations in the nef gene as well as its functions may be associated with slower HIV disease course in infected children. The proviral HIV-1 nef gene was cloned, sequenced, and compared in children with contrasting disease course: 10 long-term nonprogressors (LTNP) and six rapid progressor (RP). The CD4 and MHC-I down-modulation ability of nef alleles derived from LTNP and RP children was analyzed. We observed that only one of our 10 LTNP had a protective genetic background, and out of them, 40% had defective nef genes, carrying substitutions at the (AWLEAQ(56-61)) and the (Rxx(22-24)) domains, and that those alleles were unable of down-regulate CD4 and MHC-I. The emergence or presence of Nef L58V substitution was associated with viral attenuation, indicated by a reduction in HIV viral loads, a persistent preservation of CD4(+) T cell counts, and lack of AIDS-related symptoms. Our results demonstrate that HIV-1 perinatally infected children carrying functionally defective nef HIV-1 strains have prolonged asymptomatic phases without therapy, suggesting a relevant role of CD4 and MHC-I down-modulation Nef domains on in vivo HIV-1 pathogenesis and pediatric immunodeficiency outcome.
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Affiliation(s)
- Guillermo Corró
- Laboratorio de Biología Celular y Retrovirus, Hospital de Pediatría “Prof. Dr. Juan P. Garran,” Buenos Aires, Argentina
- Consejo Nacional de Investigaciones Científicas y Tecnológicas, Buenos Aires, Argentina
| | - Carlos A Rocco
- Laboratorio de Biología Celular y Retrovirus, Hospital de Pediatría “Prof. Dr. Juan P. Garran,” Buenos Aires, Argentina
| | - Cristian De Candia
- National Reference Center for AIDS, University of Buenos Aires, Buenos Aires, Argentina
| | - Gabriel Catano
- Veterans Administration Research Center for AIDS and HIV-1 Infection, South Texas Veterans Health Care System and Department of Medicine, University of Texas Health Science Care at San Antonio, San Antonio, Texas
| | - Gabriela Turk
- National Reference Center for AIDS, University of Buenos Aires, Buenos Aires, Argentina
| | - Andrea Mangano
- Laboratorio de Biología Celular y Retrovirus, Hospital de Pediatría “Prof. Dr. Juan P. Garran,” Buenos Aires, Argentina
- Consejo Nacional de Investigaciones Científicas y Tecnológicas, Buenos Aires, Argentina
| | - Paula C. Aulicino
- Laboratorio de Biología Celular y Retrovirus, Hospital de Pediatría “Prof. Dr. Juan P. Garran,” Buenos Aires, Argentina
- Consejo Nacional de Investigaciones Científicas y Tecnológicas, Buenos Aires, Argentina
| | - Rosa Bologna
- Servicio de Infectología, Hospital de Pediatría “Prof. Dr. Juan P. Garrahan,” Buenos Aires, Argentina
| | - Luisa Sen
- Laboratorio de Biología Celular y Retrovirus, Hospital de Pediatría “Prof. Dr. Juan P. Garran,” Buenos Aires, Argentina
- Consejo Nacional de Investigaciones Científicas y Tecnológicas, Buenos Aires, Argentina
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O'Connell RJ, Kim JH, Corey L, Michael NL. Human immunodeficiency virus vaccine trials. Cold Spring Harb Perspect Med 2012; 2:a007351. [PMID: 23209178 PMCID: PMC3543076 DOI: 10.1101/cshperspect.a007351] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
More than 2 million AIDS-related deaths occurred globally in 2008, and more than 33 million people are living with HIV/AIDS. Despite promising advances in prevention, an estimated 2.7 million new HIV infections occurred in that year, so that for every two patients placed on combination antiretroviral treatment, five people became infected. The pandemic poses a formidable challenge to the development, progress, and stability of global society 30 years after it was recognized. Experimental preventive HIV-1 vaccines have been administered to more than 44,000 human volunteers in more than 187 separate trials since 1987. Only five candidate vaccine strategies have been advanced to efficacy testing. The recombinant glycoprotein (rgp)120 subunit vaccines, AIDSVAX B/B and AIDSVAX B/E, and the Merck Adenovirus serotype (Ad)5 viral-vector expressing HIV-1 Gag, Pol, and Nef failed to show a reduction in infection rate or lowering of postinfection viral set point. Most recently, a phase III trial that tested a heterologous prime-boost vaccine combination of ALVAC-HIV vCP1521 and bivalent rgp120 (AIDSVAX B/E) showed 31% efficacy in protection from infection among community-risk Thai participants. A fifth efficacy trial testing a DNA/recombinant(r) Ad5 prime-boost combination is currently under way. We review the clinical trials of HIV vaccines that have provided insight into human immunogenicity or efficacy in preventing HIV-1 infection.
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Affiliation(s)
- Robert J O'Connell
- U.S. Military HIV Research Program, Walter Reed Army Institute of Research, Silver Spring, MD 20910, USA
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Thirty Years with HIV Infection-Nonprogression Is Still Puzzling: Lessons to Be Learned from Controllers and Long-Term Nonprogressors. AIDS Res Treat 2012; 2012:161584. [PMID: 22693657 PMCID: PMC3368166 DOI: 10.1155/2012/161584] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2012] [Accepted: 03/22/2012] [Indexed: 01/08/2023] Open
Abstract
In the early days of the HIV epidemic, it was observed that a minority of the infected patients did not progress to AIDS or death and maintained stable CD4+ cell counts. As the technique for measuring viral load became available it was evident that some of these nonprogressors in addition to preserved CD4+ cell counts had very low or even undetectable viral replication. They were therefore termed controllers, while those with viral replication were termed long-term nonprogressors (LTNPs). Genetics and virology play a role in nonprogression, but does not provide a full explanation. Therefore, host differences in the immunological response have been proposed. Moreover, the immunological response can be divided into an immune homeostasis resistant to HIV and an immune response leading to viral control. Thus, non-progression in LTNP and controllers may be due to different immunological mechanisms. Understanding the lack of disease progression and the different interactions between HIV and the immune system could ideally teach us how to develop a functional cure for HIV infection. Here we review immunological features of controllers and LTNP, highlighting differences and clinical implications.
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Immune selection in vitro reveals human immunodeficiency virus type 1 Nef sequence motifs important for its immune evasion function in vivo. J Virol 2012; 86:7126-35. [PMID: 22553319 DOI: 10.1128/jvi.00878-12] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Human immunodeficiency virus type 1 (HIV-1) Nef downregulates major histocompatibility complex class I (MHC-I), impairing the clearance of infected cells by CD8(+) cytotoxic T lymphocytes (CTLs). While sequence motifs mediating this function have been determined by in vitro mutagenesis studies of laboratory-adapted HIV-1 molecular clones, it is unclear whether the highly variable Nef sequences of primary isolates in vivo rely on the same sequence motifs. To address this issue, nef quasispecies from nine chronically HIV-1-infected persons were examined for sequence evolution and altered MHC-I downregulatory function under Gag-specific CTL immune pressure in vitro. This selection resulted in decreased nef diversity and strong purifying selection. Site-by-site analysis identified 13 codons undergoing purifying selection and 1 undergoing positive selection. Of the former, only 6 have been reported to have roles in Nef function, including 4 associated with MHC-I downregulation. Functional testing of naturally occurring in vivo polymorphisms at the 7 sites with no previously known functional role revealed 3 mutations (A84D, Y135F, and G140R) that ablated MHC-I downregulation and 3 (N52A, S169I, and V180E) that partially impaired MHC-I downregulation. Globally, the CTL pressure in vitro selected functional Nef from the in vivo quasispecies mixtures that predominately lacked MHC-I downregulatory function at the baseline. Overall, these data demonstrate that CTL pressure exerts a strong purifying selective pressure for MHC-I downregulation and identifies novel functional motifs present in Nef sequences in vivo.
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Pene-Dumitrescu T, Shu ST, Wales TE, Alvarado JJ, Shi H, Narute P, Moroco JA, Yeh JI, Engen JR, Smithgall TE. HIV-1 Nef interaction influences the ATP-binding site of the Src-family kinase, Hck. BMC CHEMICAL BIOLOGY 2012; 12:1. [PMID: 22420777 PMCID: PMC3328272 DOI: 10.1186/1472-6769-12-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/23/2011] [Accepted: 03/15/2012] [Indexed: 12/13/2022]
Abstract
Background Nef is an HIV-1 accessory protein essential for viral replication and AIDS progression. Nef interacts with a multitude of host cell signaling partners, including members of the Src kinase family. Nef preferentially activates Hck, a Src-family kinase (SFK) strongly expressed in macrophages and other HIV target cells, by binding to its regulatory SH3 domain. Recently, we identified a series of kinase inhibitors that preferentially inhibit Hck in the presence of Nef. These compounds also block Nef-dependent HIV replication, validating the Nef-SFK signaling pathway as an antiretroviral drug target. Our findings also suggested that by binding to the Hck SH3 domain, Nef indirectly affects the conformation of the kinase active site to favor inhibitor association. Results To test this hypothesis, we engineered a "gatekeeper" mutant of Hck with enhanced sensitivity to the pyrazolopyrimidine tyrosine kinase inhibitor, NaPP1. We also modified the RT loop of the Hck SH3 domain to enhance interaction of the kinase with Nef. This modification stabilized Nef:Hck interaction in solution-based kinase assays, as a way to mimic the more stable association that likely occurs at cellular membranes. Introduction of the modified RT loop rendered Hck remarkably more sensitive to activation by Nef, and led to a significant decrease in the Km for ATP as well as enhanced inhibitor potency. Conclusions These observations suggest that stable interaction with Nef may induce Src-family kinase active site conformations amenable to selective inhibitor targeting.
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Affiliation(s)
- Teodora Pene-Dumitrescu
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA 15219, USA.
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Buckheit RW, Allen TG, Alme A, Salgado M, O’Connell KA, Huculak S, Falade-Nwulia O, Williams TM, Gallant JE, Siliciano RF, Blankson JN. Host factors dictate control of viral replication in two HIV-1 controller/chronic progressor transmission pairs. Nat Commun 2012; 3:716. [PMID: 22395607 PMCID: PMC3549550 DOI: 10.1038/ncomms1697] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2011] [Accepted: 01/23/2012] [Indexed: 02/07/2023] Open
Abstract
Viremic controllers and elite controllers/suppressors maintain control over HIV-1 replication. Some studies have suggested that control is a result of infection with a defective viral strain, while others suggested host immune factors have a key role. Here we document two HIV-1 transmission pairs: one consisting of a patient with progressive disease and an individual who became an elite suppressor, and the second consisting of a patient with progressive disease and a viremic controller. In contrast to another elite suppressor transmission pair, virus isolated from all patients was fully competent. These data suggest that some viremic controllers and elite suppressors are infected with HIV-1 isolates that replicate vigorously in vitro and are able to cause progressive disease in vivo. These data suggest that host factors have a dominant role in the control of HIV-1 infection, thus it may be possible to control fully pathogenic HIV-1 isolates with therapeutic vaccination.
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Affiliation(s)
- Robert W. Buckheit
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, 733 N. Broadway, BRB 880, Baltimore, MD 21205
| | - Tracy G. Allen
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, 733 N. Broadway, BRB 880, Baltimore, MD 21205
| | - Angela Alme
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, 733 N. Broadway, BRB 880, Baltimore, MD 21205
| | - Maria Salgado
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, 733 N. Broadway, BRB 880, Baltimore, MD 21205
| | - Karen A. O’Connell
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, 733 N. Broadway, BRB 880, Baltimore, MD 21205
| | - Sarah Huculak
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, 733 N. Broadway, BRB 880, Baltimore, MD 21205
| | - Oluwaseun Falade-Nwulia
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, 733 N. Broadway, BRB 880, Baltimore, MD 21205
| | - Thomas M. Williams
- Department of Pathology, School of Medicine and Tricore Reference Laboratories, University of New Mexico, Albuquerque, New Mexico
| | - Joel E. Gallant
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, 733 N. Broadway, BRB 880, Baltimore, MD 21205
| | - Robert F. Siliciano
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, 733 N. Broadway, BRB 880, Baltimore, MD 21205
- Howard Hughes Medical Institute. Johns Hopkins University School of Medicine. 733 N. Broadway, Baltimore MD 21205, USA
| | - Joel N. Blankson
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, 733 N. Broadway, BRB 880, Baltimore, MD 21205
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Ben Haij N, Mzoughi O, Planès R, Bahraoui E. Cationic nanoglycolipidic particles as vector and adjuvant for the study of the immunogenicity of SIV Nef protein. Int J Pharm 2011; 423:116-23. [PMID: 21762763 DOI: 10.1016/j.ijpharm.2011.06.049] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2011] [Revised: 06/24/2011] [Accepted: 06/29/2011] [Indexed: 10/18/2022]
Abstract
The objective of this study was to test the immunogenicity of SIV Nef protein formulated in cationic nanoglycolipidic particles of 100nm of diameter. In parallel, the adjuvant effect of these nanoglycolipidic particles was compared in similar experiments using GST-Nef in association with the commonly strongest used complete Freund's adjuvant (CFA) or incomplete Freund's adjuvant in association with MDP or MDP alone. Our results showed that these particles do not alter the integrity of our immunogen GST-Nef, which remains stable for more than three months at 4°C. We demonstrated that in the presence of nanoglycolipidic particles antibodies against Nef were produced since the first injection and remained stable after the third injection with high titers for long lasting periods as observed with CFA and IFA/MDP adjuvant. The analysis of immunoglobulin isotype profiles of antibodies generated by the different protocols of immunization showed the preponderance of IgG1 isotypes suggesting the predominance of Th2-type immune response.
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Affiliation(s)
- Nawal Ben Haij
- Unité mixte INSERM, Université Paul Sabatier 1043, CNRS, Centre de Physiopathologie de Toulouse Purpan, CHU Purpan, Toulouse, France
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Cai CY, Zhang X, Sinko PJ, Burakoff SJ, Jin YJ. Two sorting motifs, a ubiquitination motif and a tyrosine motif, are involved in HIV-1 and simian immunodeficiency virus Nef-mediated receptor endocytosis. THE JOURNAL OF IMMUNOLOGY 2011; 186:5807-14. [PMID: 21482738 DOI: 10.4049/jimmunol.1003506] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
HIV-1 and SIV Nef proteins downregulate cell surface CD4 and MHC class I (MHC-I) molecules of infected cells, which are necessary for efficient viral replication and pathogenicity. We previously reported that K144 in HIV-1 Nef is di-ubiquitinated, and K144R substitution impairs Nef-mediated CD4 downregulation. In this report, we extend the role of ubiquitination at this lysine residue from Nef-mediated CD4 downregulation to Nef-mediated MHC-I downregulation and from HIV Nef to SIV Nef. All HIV-1 Nef mutants that contain K144R substitution are inactive in MHC-I downregulation. Tested MHC-I alleles include HLA-ABC endogenously expressed and HLA-A2 exogenously expressed in Jurkat T cells. CD4 downregulation by SIV Nef involves K176 that aligns with K144 in HIV-1 Nef, as well as an N-terminal tyrosine motif Y28Y39 not present in HIV-1 Nef. Dual mutation at K176 and Y28Y39 completely impaired SIV Nef-mediated CD4 and MHC-I downregulation, whereas a single mutation at K176 or Y28Y39 did not. The involvement of tyrosine motif in SIV Nef-mediated CD4 and MHC-I downregulation prompted us to investigate a putative tyrosine motif (Y202Y/F203) in HIV-1 Nef that is conserved among HIV-1 species. Single mutation at the tyrosine motif Y202F203 in HIV-1 Nef (NA7) greatly impaired Nef-mediated CD4 downregulation, which is similar to what we observed previously with the single mutation at lysine K144. Thus, our study demonstrated that Nef-mediated receptor endocytosis involves the ubiquitination motif and tyrosine motif.
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Affiliation(s)
- Catherine Yi Cai
- Department of Oncological Sciences, Mount Sinai School of Medicine, New York, NY 10029, USA
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Riva A, Vicenzi E, Galli M, Poli G. Strenuous resistance to natural HIV-1 disease progression: viral controllers and long-term nonprogressors. Future Virol 2011. [DOI: 10.2217/fvl.11.25] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
HIV-1 infection leads to AIDS and death within 8–10 years for most individuals in the absence of antiretroviral therapy (ART). However, a minority of infected individuals show the unusual capacity to spontaneously control disease progression after infection in the absence of any ART. So-called ‘long-term nonprogressors’ are defined by maintenance of peripheral CD4+ T-cell counts >500 cells/µl and good health without ART for >7 years since infection. More recently, ART-naive individuals who spontaneously control their viremia levels at either <50 or <2000 copies of RNA/ml for at least 12 months in the absence of ART have been named ‘elite controllers’ and ‘HIV controllers’, respectively. The overlap between long-term nonprogressors and elite controllers/HIV controllers is partial, and both groups collectively account for <5% of all infected individuals. Unraveling the nature of their relative resistance to HIV-1 disease progression would be of great value for HIV-prevention strategies.
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Affiliation(s)
- Agostino Riva
- Infectious Diseases & Immunopathology Section, Department of Clinical Sciences, L Sacco Hospital, Università di Milano, Italy
| | - Elisa Vicenzi
- Viral Pathogens & Biosafety & AIDS Immunopathogenesis Units, Division of Immunology, Transplantation & Infectious Diseases, San Raffaele Scientific Institute, Milano, Italy; P2/P3 Laboratories, Via Olgettina n 58, 20132, Milano, Italy
| | - Massimo Galli
- Infectious Diseases & Immunopathology Section, Department of Clinical Sciences, L Sacco Hospital, Università di Milano, Italy
| | - Guido Poli
- Vita-Salute San Raffaele University, School of Medicine, Milano, Italy
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Unstimulated primary CD4+ T cells from HIV-1-positive elite suppressors are fully susceptible to HIV-1 entry and productive infection. J Virol 2010; 85:979-86. [PMID: 21068257 DOI: 10.1128/jvi.01721-10] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Elite controllers or suppressors (ES) are a group of HIV-1-infected individuals who maintain viral loads below the limit of detection of commercial assays for many years. The mechanisms responsible for this remarkable control are under intense study, with the hope of developing therapeutic vaccines effective against HIV-1. In this study, we addressed the question of the intrinsic susceptibility of ES CD4(+) T cells to infection. While we and others have previously shown that CD4(+) T cells from ES can be infected by HIV-1 isolates in vitro, these studies were confounded by exogenous activation and in vitro culture of CD4(+) T cells prior to infection. In order to avoid the changes in chemokine receptor expression that have been associated with such exogenous activation, we infected purified CD4(+) T cells directly after isolation from the peripheral blood of ES, viremic patients, and uninfected donors. We utilized a green fluorescent protein (GFP)-expressing proviral construct pseudotyped with CCR5-tropic or CXCR4-tropic envelope to compare viral entry using a fluorescence resonance energy transfer-based, single-round virus-cell fusion assay. The frequency of productive infection was also compared by assessing GFP expression. CD4(+) T cells from ES were as susceptible as or more susceptible than cells from viremic patients and uninfected donors to HIV-1 entry and productive infection. The results of this physiological study strongly suggest that differences in HIV-1 entry and infection of CD4(+) T cells alone cannot explain the elite control of viral replication.
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Neri F, Giolo G, Potestà M, Petrini S, Doria M. CD4 downregulation by the human immunodeficiency virus type 1 Nef protein is dispensable for optimal output and functionality of viral particles in primary T cells. J Gen Virol 2010; 92:141-50. [PMID: 20881088 DOI: 10.1099/vir.0.026005-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Nef is a multifunctional protein of the human immunodeficiency virus type 1 (HIV-1) required for high viral replication and disease progression. Several findings indicate that the capacity of Nef to downregulate surface CD4 is essential for the protein's pathogenic activity, although the mechanisms that link the two functions are yet unclear. It is believed that, by reducing surface CD4 levels, Nef counteracts the receptor's negative effects on virion infectivity and release. Here, we show that, in 293T cells co-expressing CD4 and HIV-1, the capacity of Nef to enhance the virion incorporation of Env products and release of viral particles was mediated by retention-degradation of neo-synthesized CD4 rather than by accelerated receptor endocytosis. Different results were observed in primary CD4(+) T lymphocytes in which Nef-mediated CD4 downregulation occurs primarily by accelerated internalization. In HIV-infected T cell cultures, Nef was crucial for the removal of surface CD4 at the beginning of the infection, while later on maximal CD4 downregulation was achieved in a Nef-independent manner. Moreover, by means of in vivo selected Nef mutants, we observed that CD4 downregulation is not essential for Nef ability to enhance Env incorporation into virions and increase viral infectivity or replication in CD4(+) T lymphocytes. Notably, Nef expression itself was dispensable for efficient release of HIV-1 particles by T cells. In conclusion, we propose that the CD4 downregulation activity of Nef plays a role before the late productive phases of HIV-1 replication.
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Affiliation(s)
- Francesca Neri
- Laboratory of Immunoinfectivology, Children's Hospital Bambino Gesù, 00165 Rome, Italy
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Arnott A, Jardine D, Wilson K, Gorry PR, Merlin K, Grey P, Law MG, Dax EM, Kelleher AD, Smith DE, McPhee DA. High viral fitness during acute HIV-1 infection. PLoS One 2010; 5. [PMID: 20844589 PMCID: PMC2936565 DOI: 10.1371/journal.pone.0012631] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2010] [Accepted: 08/07/2010] [Indexed: 11/26/2022] Open
Abstract
Several clinical studies have shown that, relative to disease progression, HIV-1 isolates that are less fit are also less pathogenic. The aim of the present study was to investigate the relationship between viral fitness and control of viral load (VL) in acute and early HIV-1 infection. Samples were obtained from subjects participating in two clinical studies. In the PULSE study, antiretroviral therapy (ART) was initiated before, or no later than six months following seroconversion. Subjects then underwent multiple structured treatment interruptions (STIs). The PHAEDRA study enrolled and monitored a cohort of individuals with documented evidence of primary infection. The subset chosen were individuals identified no later than 12 months following seroconversion to HIV-1, who were not receiving ART. The relative fitness of primary isolates obtained from study participants was investigated ex vivo. Viral DNA production was quantified using a novel real time PCR assay. Following intermittent ART, the fitness of isolates obtained from 5 of 6 PULSE subjects decreased over time. In contrast, in the absence of ART the fitness of paired isolates obtained from 7 of 9 PHAEDRA subjects increased over time. However, viral fitness did not correlate with plasma VL. Most unexpected was the high relative fitness of isolates obtained at Baseline from PULSE subjects, before initiating ART. It is widely thought that the fitness of strains present during the acute phase is low relative to strains present during chronic HIV-1 infection, due to the bottleneck imposed upon transmission. The results of this study provide evidence that the relative fitness of strains present during acute HIV-1 infection may be higher than previously thought. Furthermore, that viral fitness may represent an important clinical parameter to be considered when deciding whether to initiate ART during early HIV-1 infection.
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Affiliation(s)
- Alicia Arnott
- National Serology Reference Laboratory, St Vincent’s Institute, Melbourne, Victoria, Australia
- Department of Microbiology, Monash University, Melbourne, Victoria, Australia
| | - Darren Jardine
- National Serology Reference Laboratory, St Vincent’s Institute, Melbourne, Victoria, Australia
| | - Kim Wilson
- National Serology Reference Laboratory, St Vincent’s Institute, Melbourne, Victoria, Australia
| | - Paul R. Gorry
- Burnet Institute, Melbourne, Victoria, Australia
- Department of Microbiology and Immunology, University of Melbourne, Parkville, Victoria, Australia
- Department of Medicine, Monash University, Melbourne, Victoria, Australia
| | - Kate Merlin
- National Centre in HIV Epidemiology and Clinical Research, University of New South Wales, Sydney, New South Wales, Australia
| | - Patricia Grey
- National Centre in HIV Epidemiology and Clinical Research, University of New South Wales, Sydney, New South Wales, Australia
| | - Matthew G. Law
- National Centre in HIV Epidemiology and Clinical Research, University of New South Wales, Sydney, New South Wales, Australia
| | - Elizabeth M. Dax
- National Serology Reference Laboratory, St Vincent’s Institute, Melbourne, Victoria, Australia
- Department of Microbiology and Immunology, University of Melbourne, Parkville, Victoria, Australia
| | - Anthony D. Kelleher
- National Centre in HIV Epidemiology and Clinical Research, University of New South Wales, Sydney, New South Wales, Australia
- St. Vincent’s Centre for Applied Medical Research, Sydney, New South Wales, Australia
| | - Don E. Smith
- National Centre in HIV Epidemiology and Clinical Research, University of New South Wales, Sydney, New South Wales, Australia
| | - Dale A. McPhee
- National Serology Reference Laboratory, St Vincent’s Institute, Melbourne, Victoria, Australia
- Department of Microbiology, Monash University, Melbourne, Victoria, Australia
- Department of Microbiology and Immunology, University of Melbourne, Parkville, Victoria, Australia
- * E-mail:
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Jin YJ, Zhang X, Cai C, Burakoff SJ. Alkylating HIV-1 Nef - a potential way of HIV intervention. AIDS Res Ther 2010; 7:26. [PMID: 20659345 PMCID: PMC2917394 DOI: 10.1186/1742-6405-7-26] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2010] [Accepted: 07/26/2010] [Indexed: 11/18/2022] Open
Abstract
Background Nef is a 27 KDa HIV-1 accessory protein. It downregulates CD4 from infected cell surface, a mechanism critical for efficient viral replication and pathogenicity. Agents that antagonize the Nef-mediated CD4 downregulation may offer a new class of drug to combat HIV infection and disease. TPCK (N-α-p-tosyl-L-phenylalanine chloromethyl ketone) and TLCK (N-α-p-tosyl-L-lysine chloromethyl ketone) are alkylation reagents that chemically modify the side chain of His or Cys residues in a protein. In search of chemicals that inhibit Nef function, we discovered that TPCK and TLCK alkylated HIV Nef. Methods Nef modification by TPCK was demonstrated on reducing SDS-PAGE. The specific cysteine residues modified were determined by site-directed mutagenesis and mass spectrometry (MS). The effect of TPCK modification on Nef-CD4 interaction was studied using fluorescence titration of a synthetic CD4 tail peptide with recombinant Nef-His protein. The conformational change of Nef-His protein upon TPCK-modification was monitored using CD spectrometry Results Incubation of Nef-transfected T cells, or recombinant Nef-His protein, with TPCK resulted in mobility shift of Nef on SDS-PAGE. Mutagenesis analysis indicated that the modification occurred at Cys55 and Cys206 in Nef. Mass spectrometry demonstrated that the modification was a covalent attachment (alkylation) of TPCK at Cys55 and Cys206. Cys55 is next to the CD4 binding motif (A56W57L58) in Nef required for Nef-mediated CD4 downregulation and for AIDS development. This implies that the addition of a bulky TPCK molecule to Nef at Cys55 would impair Nef function and reduce HIV pathogenicity. As expected, Cys55 modification reduced the strength of the interaction between Nef-His and CD4 tail peptide by 50%. Conclusions Our data suggest that this Cys55-specific alkylation mechanism may be exploited to develop a new class of anti HIV drugs.
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Dendritic cell-mediated HIV-1 infection of T cells demonstrates a direct relationship to plasma viral RNA levels. J Acquir Immune Defic Syndr 2010; 54:115-21. [PMID: 20386455 DOI: 10.1097/qai.0b013e3181daaf98] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
OBJECTIVE To examine the relationship between infectivity of HIV-1 variants in dendritic cell (DC)-mediated in trans infection of T cells and plasma viral RNA levels in infected subjects. METHODS HIV-1 was isolated from peripheral blood mononuclear cells of chronically infected individuals, typed for coreceptor usage, and viral replication were examined in monocyte-derived DCs-peripheral blood lymphocytes cocultures. The rate of p24 antigen production during the logarithmic phase of viral replication was determined by enzyme-linked immunosorbent assay. Additionally, nef variants were cloned and expressed in trans with a HIV luciferase vector and CCR5-tropic HIV-1 envelope, and infectivity was measured in DC-mediated capture-transfer assays. RESULTS Replication capacity of HIV-1 viral CCR5-tropic isolates in monocyte-derived dendritic cells-peripheral blood lymphocytes cocultures was linearly associated with the plasma viral RNA levels in a cohort of HIV-1-infected individuals exhibiting an inverse relationship between plasma viral RNA and CD4 cell count. Furthermore, infectivity activity of nef variants in context of DC-mediated enhanced infection of T cells also showed a linear relationship to plasma viral RNA levels. CONCLUSIONS These results illustrate that replication capacity of HIV-1 in DC T-cell cultures is a significant determinant of plasma viral RNA level. The data suggest that adaptation of HIV-1 to DC interactions with T cells influences the level of viral replication in the host.
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Pushker R, Jacqué JM, Shields DC. Meta-analysis to test the association of HIV-1 nef amino acid differences and deletions with disease progression. J Virol 2010; 84:3644-53. [PMID: 20071583 PMCID: PMC2838144 DOI: 10.1128/jvi.01959-09] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2009] [Accepted: 12/30/2009] [Indexed: 11/20/2022] Open
Abstract
Previous relatively small studies have associated particular amino acid replacements and deletions in the HIV-1 nef gene with differences in the rate of HIV disease progression. We tested more rigorously whether particular nef amino acid differences and deletions are associated with HIV disease progression. Amino acid replacements and deletions in patients' consensus sequences were investigated for 153 progressor (P), 615 long-term nonprogressor (LTNP), and 2,311 unknown progressor sequences from 582 subtype B HIV-infected patients. LTNPs had more defective nefs (interrupted by frameshifts or stop codons), but on a per-patient basis there was no excess of LTNP patients with one or more defective nef sequences compared to the Ps (P = 0.47). The high frequency of amino acid replacement at residues S(8), V(10), I(11), A(15), V(85), V(133), N(157), S(163), V(168), D(174), R(178), E(182), and R(188) in LTNPs was also seen in permuted datasets, implying that these are simply rapidly evolving residues. Permutation testing revealed that residues showing the greatest excess over expectation (A(15), V(85), N(157), S(163), V(168), D(174), R(178), and R(188)) were not significant (P = 0.77). Exploratory analysis suggested a hypothetical excess of frameshifting in the regions (9)SVIG and (118)QGYF among LTNPs. The regions V(10) and (152)KVEEA of nef were commonly deleted in LTNPs. However, permutation testing indicated that none of the regions displayed significantly excessive deletion in LTNPs. In conclusion, meta-analysis of HIV-1 nef sequences provides no clear evidence of whether defective nef sequences or particular regions of the protein play a significant role in disease progression.
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Affiliation(s)
- Ravindra Pushker
- UCD Complex and Adaptive Systems Laboratory, UCD Conway Institute of Biomolecular and Biomedical Research, School of Medicine and Medical Science, Centre for Research in Infectious Diseases, University College Dublin, Belfield, Dublin 4, Ireland
| | - Jean-Marc Jacqué
- UCD Complex and Adaptive Systems Laboratory, UCD Conway Institute of Biomolecular and Biomedical Research, School of Medicine and Medical Science, Centre for Research in Infectious Diseases, University College Dublin, Belfield, Dublin 4, Ireland
| | - Denis C. Shields
- UCD Complex and Adaptive Systems Laboratory, UCD Conway Institute of Biomolecular and Biomedical Research, School of Medicine and Medical Science, Centre for Research in Infectious Diseases, University College Dublin, Belfield, Dublin 4, Ireland
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Replicative capacity of human immunodeficiency virus type 1 transmitted from mother to child is associated with pediatric disease progression rate. J Virol 2010; 84:492-502. [PMID: 19828603 DOI: 10.1128/jvi.01743-09] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Human immunodeficiency virus (HIV)-infected infants in the developing world typically progress to AIDS or death within the first 2 years of life. However, a minority progress relatively slowly. This study addresses the potential contribution of viral factors to HIV disease progression in eight infants selected from a well-characterized cohort of C clade HIV-infected infants, monitored prospectively from birth in Durban, South Africa. Three infants were defined as "progressors," and five were defined as "slow progressors." We observed that slow-progressor infants carry HIV isolates with significantly lower replicative capacity compared to virus from progressors. Furthermore, our data suggest a link between the attenuated viral phenotype and HLA-B* 57/5801 epitope-specific Gag mutational patterns of the transmitted virus and not to coreceptor usage or to the presence of Nef deletions or insertions. These data underline the importance of virus-host interactions and highlight the contribution of viral attenuation through Gag-specific CD8(+) T-cell escape mutations, among other factors, in the control of pediatric HIV infection.
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Emert-Sedlak L, Kodama T, Lerner EC, Dai W, Foster C, Day BW, Lazo JS, Smithgall TE. Chemical library screens targeting an HIV-1 accessory factor/host cell kinase complex identify novel antiretroviral compounds. ACS Chem Biol 2009; 4:939-47. [PMID: 19807124 DOI: 10.1021/cb900195c] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Nef is an HIV-1 accessory protein essential for AIDS progression and an attractive target for drug discovery. Lack of a catalytic function makes Nef difficult to assay in chemical library screens. We developed a high-throughput screening assay for inhibitors of Nef function by coupling it to one of its host cell binding partners, the Src-family kinase Hck. Hck activation is dependent upon Nef in this assay, providing a direct readout of Nef activity in vitro. Using this screen, a unique diphenylfuropyrimidine was identified as a strong inhibitor of Nef-dependent Hck activation. This compound also exhibited remarkable antiretroviral effects, blocking Nef-dependent HIV replication in cell culture. Structurally related analogs were synthesized and shown to exhibit similar Nef-dependent antiviral activity, identifying the diphenylfuropyrimidine substructure as a new lead for antiretroviral drug development. This study demonstrates that coupling noncatalytic HIV accessory factors with host cell target proteins addressable by high-throughput assays may afford new avenues for the discovery of anti-HIV agents.
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Affiliation(s)
- Lori Emert-Sedlak
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261
| | - Toshiaki Kodama
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261
| | - Edwina C. Lerner
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261
| | - Weixiang Dai
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, Pennsylvania 15261
| | - Caleb Foster
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261
- Drug Discovery Institute, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261
| | - Billy W. Day
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, Pennsylvania 15261
- Drug Discovery Institute, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260
| | - John S. Lazo
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261
- Drug Discovery Institute, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261
| | - Thomas E. Smithgall
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261
- Drug Discovery Institute, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261
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Blankson JN. Effector mechanisms in HIV-1 infected elite controllers: highly active immune responses? Antiviral Res 2009; 85:295-302. [PMID: 19733595 DOI: 10.1016/j.antiviral.2009.08.007] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2009] [Revised: 07/30/2009] [Accepted: 08/30/2009] [Indexed: 10/20/2022]
Abstract
Elite controllers (EC) are HIV-1 infected patients control viral replication to a level of <50 copies/ml without antiretroviral therapy. These patients are also known as elite suppressors, or HIV controllers, and they differ from traditional long-term non-progressors (LTNPs) who maintain stable CD4 counts and are asymptomatic without antiretroviral therapy. Recent studies suggest that many EC are infected with replication-competent virus. Thus it appears that host factors such as innate immunity, the humoral immune response, and the cellular immune response are involved in the suppression of viral replication in EC. This article will review the effector mechanisms that are thought to play a role in the remarkable control of viral replication seen in these patients. This article forms part of a special issue of Antiviral Research marking the 25th anniversary of antiretroviral drug discovery and development, Vol 85, issue 1, 2010.
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Affiliation(s)
- Joel N Blankson
- Broadway Research Bldg, Rm 880, Johns Hopkins University School of Medicine, 722 N. Broadway, Baltimore, MD 21205, United States.
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45
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Effective downregulation of HLA-A*2 and HLA-B*57 by primary human immunodeficiency virus type 1 isolates cultured from elite suppressors. J Virol 2009; 83:6941-6. [PMID: 19386719 DOI: 10.1128/jvi.00306-09] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Elite controllers or suppressors (ES) are human immunodeficiency virus type 1 (HIV-1)-infected patients who control viral replication to <50 copies/ml without antiretroviral therapy. Downregulation of HLA class I molecules is an important mechanism used by HIV-1 to evade the immune system. In this study, we showed that primary isolates from ES are as effective as isolates obtained from patients with progressive HIV-1 disease at downregulating HLA-A*2 and HLA-B*57 molecules on primary CD4(+) T cells. Thus, a diminished ability of viral isolates from ES to evade HIV-specific immune responses probably does not contribute to the control of viral replication in these patients.
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Schmökel J, Li H, Bailes E, Schindler M, Silvestri G, Hahn BH, Apetrei C, Kirchhoff F. Conservation of Nef function across highly diverse lineages of SIVsmm. Retrovirology 2009; 6:36. [PMID: 19358735 PMCID: PMC2678078 DOI: 10.1186/1742-4690-6-36] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2008] [Accepted: 04/09/2009] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND SIVsmm is a simian immunodeficiency virus that persists efficiently without causing disease in naturally infected sooty mangabeys (SMs) but induces AIDS upon cross-species transmission to humans and macaques. Current phylogenetic data indicate that SIVsmm strains comprise a highly diverse group of viruses that can be subdivided into different lineages. Since only certain SIVsmm strains have successfully crossed the species barrier to humans and macaques, the question has been raised whether there are lineage specific differences in SIVsmm biology. In the present study we examined whether representatives of five different SIVsmm lineages show differences in the function of the accessory Nef protein, which plays an important role in viral persistence, transmission and pathogenesis. RESULTS We found that nef alleles from all SIVsmm lineages down-modulated CD4, MHC-I, CD28 and CD3 and up-regulated the invariant chain (Ii) associated with immature MHC-II molecules in human-derived cells. Moreover, they generally suppressed the responsiveness of virally infected T cells to activation, enhanced virion infectivity and promoted virus replication in human peripheral blood mononuclear cells. The functional activity of these nef alleles in the various assays varied substantially between different strains of SIVsmm but quantitative analyses did not reveal any significant lineage-specific differences in Nef function. CONCLUSION Nef alleles from different lineages of SIVsmm do not require adaptive changes to be functionally active in human cells. Strain rather than lineage-specific differences in Nef function may impact the virological and immunological feature of SIVsmm in SMs and possibly affected viral fitness and pathogenicity in human and macaque hosts.
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Affiliation(s)
- Jan Schmökel
- Institute of Virology, University of Ulm, 89081 Ulm, Germany.
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Green LA, Liu Y, He JJ. Inhibition of HIV-1 infection and replication by enhancing viral incorporation of innate anti-HIV-1 protein A3G: a non-pathogenic Nef mutant-based anti-HIV strategy. J Biol Chem 2009; 284:13363-13372. [PMID: 19324886 DOI: 10.1074/jbc.m806631200] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
APOBEC3G (A3G) is a cellular protein that has been identified as an innate anti-human immunodeficiency virus type 1 (HIV-1) factor. One of the major functions of HIV-1 virion infectivity protein (Vif) protein is to target A3G for ubiquitination/proteasome-mediated degradation and, as a result, evade the host innate defense mechanism. Thus, we wished to devise a strategy to restore the anti-HIV activity of A3G by actively targeting it into HIV-1 virions and countering HIV-1 Vif-targeted degradation. In the current study we performed a series of proof-of-concept experiments for this strategy using as a delivery vehicle of A3G, a derivate of non-pathogenic Nef mutant Nef7 that is capable of being efficiently incorporated into HIV-1 virions. We demonstrate that the Nef7.A3G fusion protein retains several important properties of Nef7; that is, the higher virion incorporation efficiency, no PAK-2 (p21-activated kinase 2) activation, and no CD4 and major histocompatibility complex I down-regulation. Meanwhile, we show that virion incorporated Nef7.A3G possesses the anti-HIV infectivity function of A3G. Moreover, we show that virus-like particle-mediated inverse fusion delivery of Nef7.A3G into HIV-infected CD4+ T lymphocytes leads to potent inhibition of HIV-1 replication in these cells. Taken together, these results indicate that Nef7.A3G can effectively restrict HIV infection and replication by restoring the virion incorporation of A3G, even in the presence of Vif.
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Affiliation(s)
- Linden A Green
- Department of Microbiology and Immunology Walther Cancer Institute, Indianapolis, Indiana 46206
| | - Ying Liu
- Department of Microbiology and Immunology Walther Cancer Institute, Indianapolis, Indiana 46206
| | - Johnny J He
- Department of Microbiology and Immunology Walther Cancer Institute, Indianapolis, Indiana 46206; Center for AIDS Research Walther Cancer Institute, Indianapolis, Indiana 46206; Walther Oncology Center, Indiana University School of Medicine and Walther Cancer Institute, Indianapolis, Indiana 46206; Walther Cancer Institute, Indianapolis, Indiana 46206.
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48
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Arhel NJ, Kirchhoff F. Implications of Nef: host cell interactions in viral persistence and progression to AIDS. Curr Top Microbiol Immunol 2009; 339:147-75. [PMID: 20012528 DOI: 10.1007/978-3-642-02175-6_8] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The HIV and SIV Nef accessory proteins are potent enhancers of viral persistence and accelerate progression to AIDS in HIV-1-infected patients and non-human primate models. Although relatively small (27-35 kD), Nef can interact with a multitude of cellular factors and induce complex changes in trafficking, signal transduction, and gene expression that together converge to promote viral replication and immune evasion. In particular, Nef recruits several immunologically relevant cellular receptors to the endocytic machinery to reduce the recognition and elimination of virally infected cells by the host immune system, while simultaneously interacting with various kinases to promote T cell activation and viral replication. This review provides an overview on selected Nef interactions with host cell proteins, and discusses their possible relevance for viral spread and pathogenicity.
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Affiliation(s)
- Nathalie J Arhel
- Institute of Virology, Universitätsklinikum Ulm, Albert-Einstein-Allee 11, 89081 Ulm, Germany
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Chaudhry A, Das SR, Jameel S, George A, Bal V, Mayor S, Rath S. HIV-1 Nef Induces a Rab11-Dependent Routing of Endocytosed Immune Costimulatory Proteins CD80 and CD86 to the Golgi. Traffic 2008; 9:1925-35. [DOI: 10.1111/j.1600-0854.2008.00802.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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50
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Jin YJ, Cai CY, Zhang X, Burakoff SJ. Lysine 144, a ubiquitin attachment site in HIV-1 Nef, is required for Nef-mediated CD4 down-regulation. THE JOURNAL OF IMMUNOLOGY 2008; 180:7878-86. [PMID: 18523251 DOI: 10.4049/jimmunol.180.12.7878] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Nef is a HIV-1 accessory protein critical for the replication of the virus and the development of AIDS. The major pathological activity of Nef is the down-regulation of CD4, the primary receptor of HIV-1 infection. The mechanism underlying Nef-mediated CD4 endocytosis and degradation remains incompletely understood. Since protein ubiquitination is the predominant sorting signal in receptor endocytosis, we investigated whether Nef is ubiquitinated. The in vivo ubiquitination assay showed that both HIV-1 and SIV Nef proteins expressed in Jurkat T cells and 293T cells were multiple ubiquitinated by ubiquitin-His. The lysine-free HIV-1 Nef mutant (Delta10K) generated by replacing all 10 lysines with arginines was not ubiquitinated and the major ubiquitin-His attachment sites in HIV-1 Nef were determined to be lysine 144 (di-ubiquitinated) and lysine 204 (mono-ubiquitinated). Lysine-free HIV-1 Nef was completely inactive in Nef-mediated CD4 down-regulation, so was the Nef mutant with a single arginine substitution at K144 but not at K204. A mutant HIV-1 provirion NL4-3 with a single arginine substitution in Nef at K144 was also inactive in Nef-mediated CD4 down-regulation. Lysine-free Nef mutant reintroduced with lysine 144 (DeltaK10 + K144) was shown active in CD4 down-regulation. These data suggest that ubiquitination of Nef, particularly diubiquitination of the lysine 144, is necessary for Nef-mediated CD4 down-regulation.
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Affiliation(s)
- Yong-Jiu Jin
- Department of Medicine, New York University School of Medicine, New York, NY 10016, USA.
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