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Arthos J, Cicala C, Nawaz F, Byrareddy SN, Villinger F, Santangelo PJ, Ansari AA, Fauci AS. The Role of Integrin α 4β 7 in HIV Pathogenesis and Treatment. Curr HIV/AIDS Rep 2018; 15:127-135. [PMID: 29478152 PMCID: PMC5882766 DOI: 10.1007/s11904-018-0382-3] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
PURPOSE OF REVIEW Acute HIV infection is characterized by high-level viral replication throughout the body's lymphoid system, particularly in gut-associated lymphoid tissues resulting in damage to structural components of gut tissue. This damage is irreversible and believed to contribute to the development of immune deficiencies. Antiretroviral therapy (ART) does not restore gut structure and function. Studies in macaques point to an alternative treatment strategy that may ameliorate gut damage. Integrin α4β7 mediates the homing of lymphocytes to gut tissues. Vedolizumab, a monoclonal antibody (mAb) antagonist of α4β7, has demonstrated efficacy and has been approved for the treatment of inflammatory bowel disease in humans. Here, we describe our current knowledge, and the gaps in our understanding, of the role of α4β7 in HIV pathogenesis and treatment. RECENT FINDINGS When administered to macaques prior to infection, a nonhuman primate analogue of vedolizumab prevents transmission of SIV. In combination with ART, this mAb facilitates durable virologic control following treatment interruption. Targeting α4β7 represents a novel therapeutic approach to prevent and treat HIV infection.
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Affiliation(s)
- James Arthos
- Laboratory of Immunoregulation, National Institutes of Allergy & Infectious Diseases, National Institutes of Health, 10 Center Drive Rm 6A08, Bethesda, MD, 20814, USA.
| | - Claudia Cicala
- Laboratory of Immunoregulation, National Institutes of Allergy & Infectious Diseases, National Institutes of Health, 10 Center Drive Rm 6A08, Bethesda, MD, 20814, USA
| | - Fatima Nawaz
- Laboratory of Immunoregulation, National Institutes of Allergy & Infectious Diseases, National Institutes of Health, 10 Center Drive Rm 6A08, Bethesda, MD, 20814, USA
| | - Siddappa N Byrareddy
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE, 68198, USA
| | - Francois Villinger
- New Iberia Research Center, University of Louisiana Lafayette, Lafayette, LA, 70560, USA
| | - Philip J Santangelo
- Walter H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA, 30680, USA
| | - Aftab A Ansari
- Department of Pathology & Laboratory Medicine, Emory University School of Medicine, Atlanta, GA, 30322, USA
| | - Anthony S Fauci
- Laboratory of Immunoregulation, National Institutes of Allergy & Infectious Diseases, National Institutes of Health, 10 Center Drive Rm 6A08, Bethesda, MD, 20814, USA
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102
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Chase AJ, Wombacher R, Fackler OT. Intrinsic properties and plasma membrane trafficking route of Src family kinase SH4 domains sensitive to retargeting by HIV-1 Nef. J Biol Chem 2018; 293:7824-7840. [PMID: 29588370 DOI: 10.1074/jbc.ra118.002794] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Indexed: 01/18/2023] Open
Abstract
The HIV type 1 pathogenicity factor Nef enhances viral replication by modulating multiple host cell pathways, including tuning the activation state of infected CD4 T lymphocytes to optimize virus spread. For this, Nef inhibits anterograde transport of the Src family kinase (SFK) Lck toward the plasma membrane (PM). This leads to retargeting of the kinase to the trans-Golgi network, whereas the intracellular transport of a related SFK, Fyn, is unaffected by Nef. The 18-amino acid Src homology 4 (SH4) domain membrane anchor of Lck is necessary and sufficient for Nef-mediated retargeting, but other details of this process are not known. The goal of this study was therefore to identify characteristics of SH4 domains responsive to Nef and the transport machinery used. Screening a panel of SFK SH4 domains revealed two groups that were sensitive or insensitive for trans-Golgi network retargeting by Nef as well as the importance of the amino acid at position 8 for determining Nef sensitivity. Anterograde transport of Nef-sensitive domains was characterized by slower delivery to the PM and initial targeting to Golgi membranes, where transport was arrested in the presence of Nef. For Nef-sensitive SH4 domains, ectopic expression of the lipoprotein binding chaperone Unc119a or the GTPase Arl3 or reduction of their endogenous expression phenocopied the effect of Nef. Together, these results suggest that, analogous to K-Ras, Nef-sensitive SH4 domains are transported to the PM by a cycle of solubilization and membrane insertion and that intrinsic properties define SH4 domains as cargo of this Nef-sensitive lipoprotein binding chaperone-GTPase transport cycle.
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Affiliation(s)
- Amanda J Chase
- From the Department of Infectious Diseases, Center for Integrative Infectious Disease Research (CIID), Integrative Virology, University Hospital Heidelberg, Im Neuenheimer Feld 344, 69120 Heidelberg, Germany
| | - Rebecka Wombacher
- From the Department of Infectious Diseases, Center for Integrative Infectious Disease Research (CIID), Integrative Virology, University Hospital Heidelberg, Im Neuenheimer Feld 344, 69120 Heidelberg, Germany
| | - Oliver T Fackler
- From the Department of Infectious Diseases, Center for Integrative Infectious Disease Research (CIID), Integrative Virology, University Hospital Heidelberg, Im Neuenheimer Feld 344, 69120 Heidelberg, Germany
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103
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Wu M, Alvarado JJ, Augelli-Szafran CE, Ptak RG, Smithgall TE. A single β-octyl glucoside molecule induces HIV-1 Nef dimer formation in the absence of partner protein binding. PLoS One 2018; 13:e0192512. [PMID: 29415006 PMCID: PMC5802939 DOI: 10.1371/journal.pone.0192512] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Accepted: 01/24/2018] [Indexed: 01/05/2023] Open
Abstract
The HIV-1 Nef accessory protein is essential for viral pathogenicity and AIDS progression. Nef forms complexes with multiple host cell factors to facilitate viral replication and promote immune escape of HIV-infected cells. Previous X-ray crystal structures demonstrate that Nef forms homodimers, the orientation of which are influenced by host cell binding partners. In cell-based fluorescence complementation assays, Nef forms homodimers at the plasma membrane. However, recombinant Nef proteins often exist as monomers in solution, suggesting that membrane interaction may also trigger monomer to dimer transitions. In this study, we show that monomeric Nef core proteins can be induced to form dimers in the presence of low concentrations of the non-ionic surfactant, β-octyl glucoside (βOG). X-ray crystallography revealed that a single βOG molecule is present in the Nef dimer, with the 8-carbon acyl chain of the ligand binding to a hydrophobic pocket formed by the dimer interface. This Nef-βOG dimer interface involves helix αB, as observed in previous dimer structures, as well as a helix formed by N-terminal residues 54-66. Nef dimer formation is stabilized in solution by the addition of βOG, providing biochemical validation for the crystal structure. These observations together suggest that the interaction with host cell lipid mediators or other hydrophobic ligands may play a role in Nef dimerization, which has been previously linked to multiple Nef functions including host cell protein kinase activation, CD4 downregulation, and enhancement of HIV-1 replication.
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Affiliation(s)
- Mousheng Wu
- Department of Chemistry, Drug Discovery Division, Southern Research Institute, Birmingham, AL, United States of America
| | - John J. Alvarado
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States of America
| | - Corinne E. Augelli-Szafran
- Department of Chemistry, Drug Discovery Division, Southern Research Institute, Birmingham, AL, United States of America
| | - Roger G. Ptak
- Department of Infectious Disease Research, Southern Research Institute, Frederick, MD, United States of America
| | - Thomas E. Smithgall
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States of America
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104
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McNamara RP, Costantini LM, Myers TA, Schouest B, Maness NJ, Griffith JD, Damania BA, MacLean AG, Dittmer DP. Nef Secretion into Extracellular Vesicles or Exosomes Is Conserved across Human and Simian Immunodeficiency Viruses. mBio 2018; 9:e02344-17. [PMID: 29437924 PMCID: PMC5801467 DOI: 10.1128/mbio.02344-17] [Citation(s) in RCA: 81] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Accepted: 01/10/2018] [Indexed: 02/07/2023] Open
Abstract
Extracellular vesicles (EVs) or exosomes have been implicated in the pathophysiology of infections and cancer. The negative regulatory factor (Nef) encoded by simian immunodeficiency virus (SIV) and human immunodeficiency virus (HIV) plays a critical role in the progression to AIDS and impairs endosomal trafficking. Whether HIV-1 Nef can be loaded into EVs has been the subject of controversy, and nothing is known about the connection between SIV Nef and EVs. We find that both SIV and HIV-1 Nef proteins are present in affinity-purified EVs derived from cultured cells, as well as in EVs from SIV-infected macaques. Nef-positive EVs were functional, i.e., capable of membrane fusion and depositing their content into recipient cells. The EVs were able to transfer Nef into recipient cells. This suggests that Nef readily enters the exosome biogenesis pathway, whereas HIV virions are assembled at the plasma membrane. It suggests a novel mechanism by which lentiviruses can influence uninfected and uninfectable, i.e., CD4-negative, cells.IMPORTANCE Extracellular vesicles (EVs) transfer biologically active materials from one cell to another, either within the adjacent microenvironment or further removed. EVs also package viral RNAs, microRNAs, and proteins, which contributes to the pathophysiology of infection. In this report, we show that both human immunodeficiency virus (HIV) and simian immunodeficiency virus (SIV) incorporate the virus-encoded Nef protein into EVs, including EVs circulating in the blood of SIV-infected macaques and that this presents a novel mechanism of Nef transfer to naive and even otherwise non-infectable cells. Nef is dispensable for viral replication but essential for AIDS progression in vivo Demonstrating that Nef incorporation into EVs is conserved across species implicates EVs as novel mediators of the pathophysiology of HIV. It could help explain the biological effects that HIV has on CD4-negative cells and EVs could become biomarkers of disease progression.
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Affiliation(s)
- Ryan P McNamara
- Department of Microbiology and Immunology, Lineberger Comprehensive Cancer Center, School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Lindsey M Costantini
- Department of Microbiology and Immunology, Lineberger Comprehensive Cancer Center, School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - T Alix Myers
- Tulane National Primate Research Center, Tulane University, Covington, Louisiana, USA
| | - Blake Schouest
- Tulane National Primate Research Center, Tulane University, Covington, Louisiana, USA
| | - Nicholas J Maness
- Tulane National Primate Research Center, Tulane University, Covington, Louisiana, USA
| | - Jack D Griffith
- Department of Microbiology and Immunology, Lineberger Comprehensive Cancer Center, School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Blossom A Damania
- Department of Microbiology and Immunology, Lineberger Comprehensive Cancer Center, School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Andrew G MacLean
- Tulane National Primate Research Center, Tulane University, Covington, Louisiana, USA
| | - Dirk P Dittmer
- Department of Microbiology and Immunology, Lineberger Comprehensive Cancer Center, School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
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105
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Moroco JA, Alvarado JJ, Staudt RP, Shi H, Wales TE, Smithgall TE, Engen JR. Remodeling of HIV-1 Nef Structure by Src-Family Kinase Binding. J Mol Biol 2018; 430:310-321. [PMID: 29258818 PMCID: PMC5801098 DOI: 10.1016/j.jmb.2017.12.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Revised: 12/07/2017] [Accepted: 12/10/2017] [Indexed: 11/25/2022]
Abstract
The HIV-1 accessory protein Nef controls multiple aspects of the viral life cycle and host immune response, making it an attractive therapeutic target. Previous X-ray crystal structures of Nef in complex with key host cell binding partners have shed light on protein-protein interactions critical to Nef function. Crystal structures of Nef in complex with either the SH3 or tandem SH3-SH2 domains of Src-family kinases reveal distinct dimer conformations of Nef. However, the existence of these Nef dimer complexes in solution has not been established. Here we used hydrogen exchange mass spectrometry (HX MS) to compare the solution conformation of Nef alone and in complexes with the SH3 or the SH3-SH2 domains of the Src-family kinase Hck. HX MS revealed that interaction with the Hck SH3 or tandem SH3-SH2 domains induces protection of the Nef αB-helix from deuterium uptake, consistent with a role for αB in dimer formation. HX MS analysis of a Nef mutant (position Asp123, a site buried in the Nef:SH3 dimer but surface exposed in the Nef:SH3-SH2 complex), showed a Hck-induced conformational change in Nef relative to wild-type Nef. These results support a model in which Src-family kinase binding induces conformational changes in Nef to expose residues critical for interaction with the μ1 subunit of adaptor protein 1 and the major histocompatibility complex-1 tail, and subsequent major histocompatibility complex-1 downregulation and immune escape of HIV-infected cells required for functional interactions with downstream binding partners.
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Affiliation(s)
- Jamie A Moroco
- Department of Chemistry and Chemical Biology, Maildrop 412TF, Northeastern University, 360 Huntington Avenue, Boston, MA 02115, USA.
| | - John Jeff Alvarado
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Bridgeside Point II, Suite 523, 450 Technology Drive, Pittsburgh, PA 15219, USA.
| | - Ryan P Staudt
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Bridgeside Point II, Suite 523, 450 Technology Drive, Pittsburgh, PA 15219, USA.
| | - Haibin Shi
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Bridgeside Point II, Suite 523, 450 Technology Drive, Pittsburgh, PA 15219, USA.
| | - Thomas E Wales
- Department of Chemistry and Chemical Biology, Maildrop 412TF, Northeastern University, 360 Huntington Avenue, Boston, MA 02115, USA.
| | - Thomas E Smithgall
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Bridgeside Point II, Suite 523, 450 Technology Drive, Pittsburgh, PA 15219, USA.
| | - John R Engen
- Department of Chemistry and Chemical Biology, Maildrop 412TF, Northeastern University, 360 Huntington Avenue, Boston, MA 02115, USA.
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106
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Dai W, Usami Y, Wu Y, Göttlinger H. A Long Cytoplasmic Loop Governs the Sensitivity of the Anti-viral Host Protein SERINC5 to HIV-1 Nef. Cell Rep 2018; 22:869-875. [PMID: 29386131 PMCID: PMC5810964 DOI: 10.1016/j.celrep.2017.12.082] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Revised: 12/05/2017] [Accepted: 12/22/2017] [Indexed: 12/14/2022] Open
Abstract
We recently identified the multipass transmembrane protein SERINC5 as an antiviral protein that can potently inhibit HIV-1 infectivity and is counteracted by HIV-1 Nef. We now report that the anti-HIV-1 activity, but not the sensitivity to Nef, is conserved among vertebrate SERINC5 proteins. However, a Nef-resistant SERINC5 became Nef sensitive when its intracellular loop 4 (ICL4) was replaced by that of Nef-sensitive human SERINC5. Conversely, human SERINC5 became resistant to Nef when its ICL4 was replaced by that of a Nef-resistant SERINC5. In general, ICL4 regions from SERINCs that exhibited resistance to a given Nef conferred resistance to the same Nef when transferred to a sensitive SERINC, and vice versa. Our results establish that human SERINC5 can be modified to restrict HIV-1 infectivity even in the presence of Nef.
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Affiliation(s)
- Weiwei Dai
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Yoshiko Usami
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Yuanfei Wu
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Heinrich Göttlinger
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Medical School, Worcester, MA 01605, USA.
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107
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Schulte B, Selyutina A, Opp S, Herschhorn A, Sodroski JG, Pizzato M, Diaz-Griffero F. Localization to detergent-resistant membranes and HIV-1 core entry inhibition correlate with HIV-1 restriction by SERINC5. Virology 2017; 515:52-65. [PMID: 29268082 DOI: 10.1016/j.virol.2017.12.005] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Revised: 12/08/2017] [Accepted: 12/09/2017] [Indexed: 12/30/2022]
Abstract
SERINC5(S5) is a multi-span transmembrane protein that potently blocks the infectivity of HIV-1 produced by human T-cells. The ability of S5 to restrict infectivity correlates with its presence in the virion, but the exact mechanism by which S5 restricts HIV-1 is unknown. Here we tested whether the core from HIV-1 virions containing S5 is delivered to the cytoplasm. Using the "fate of the capsid" assay, we demonstrated that the viral core of S5-restricted HIV-1 does not reach the cytoplasm of target cells, suggesting a block in the delivery of the core to the cytoplasm. In agreement with evidence suggesting that the viral determinants for S5 restriction map to the envelope of HIV-1, we observed that S5 induces conformational changes to the HIV-1 envelope. Further, we demonstrated that S5 localizes to detergent-resistant membranes (DRMs), as has been shown previously for the HIV-1 envelope in producer cells. In order to identify the determinants of S5 restriction, we explored the ability of all human SERINC proteins to restrict HIV-1. In contrast to human S5, we observed that human SERINC2(S2) did not restrict HIV-1, and was inefficiently incorporated into HIV-1 virions when compared to S5. Experiments using S5-S2 chimeric proteins revealed two functional domains for restriction: one necessary for S5 incorporation into virions, which does not seem to be necessary for restriction, and a second one necessary to change the HIV-1 envelope conformation, localize to DRMs, and block infection.
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Affiliation(s)
- Bianca Schulte
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Anastasia Selyutina
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Silvana Opp
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Alon Herschhorn
- Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02215, USA
| | - Joseph G Sodroski
- Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02215, USA
| | - Massimo Pizzato
- University of Trento, Centre for Integrative Biology, 38123 Trento, Italy
| | - Felipe Diaz-Griffero
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
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108
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SERINC as a Restriction Factor to Inhibit Viral Infectivity and the Interaction with HIV. J Immunol Res 2017; 2017:1548905. [PMID: 29359168 PMCID: PMC5735641 DOI: 10.1155/2017/1548905] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Revised: 10/22/2017] [Accepted: 11/02/2017] [Indexed: 12/16/2022] Open
Abstract
The serine incorporator 5 (SERINC5) is a recently discovered restriction factor that inhibits viral infectivity by preventing fusion. Retroviruses have developed strategies to counteract the action of SERINC5, such as the expression of proteins like negative regulatory factor (Nef), S2, and glycosylated Gag (glycoGag). These accessory proteins downregulate SERINC5 from the plasma membrane for subsequent degradation in the lysosomes. The observed variability in the action of SERINC5 suggests the participation of other elements like the envelope glycoprotein (Env) that modulates susceptibility of the virus towards SERINC5. The exact mechanism by which SERINC5 inhibits viral fusion has not yet been determined, although it has been proposed that it increases the sensitivity of the Env by exposing regions which are recognized by neutralizing antibodies. More studies are needed to understand the role of SERINC5 and to assess its utility as a therapeutic strategy.
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109
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Lamers SL, Fogel GB, Liu ES, Barbier AE, Rodriguez CW, Singer EJ, Nolan DJ, Rose R, McGrath MS. Brain-specific HIV Nef identified in multiple patients with neurological disease. J Neurovirol 2017; 24:1-15. [PMID: 29063512 DOI: 10.1007/s13365-017-0586-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Revised: 08/28/2017] [Accepted: 10/03/2017] [Indexed: 12/11/2022]
Abstract
HIV-1 Nef is a flexible, multifunctional protein with several cellular targets that is required for pathogenicity of the virus. This protein maintains a high degree of genetic variation among intra- and inter-host isolates. HIV Nef is relevant to HIV-associated neurological diseases (HAND) in patients treated with combined antiretroviral therapy because of the protein's role in promoting survival and migration of infected brain macrophages. In this study, we analyzed 2020 HIV Nef sequences derived from 22 different tissues and 31 subjects using a novel computational approach. This approach combines statistical regression and evolved neural networks (ENNs) to classify brain sequences based on the physical and chemical characteristics of functional Nef domains. Based on training, testing, and validation data, the method successfully classified brain Nef sequences at 84.5% and provided informative features for further examination. These included physicochemical features associated with the Src-homology-3 binding domain, the Nef loop (including the AP-2 Binding region), and a cytokine-binding domain. Non-brain sequences from patients with HIV-associated neurological disease were frequently classified as brain, suggesting that the approach could indicate neurological risk using blood-derived virus or for the development of biomarkers for use in assay systems aimed at drug efficacy studies for the treatment of HIV-associated neurological diseases.
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110
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Seki S, Nomura T, Nishizawa M, Yamamoto H, Ishii H, Matsuoka S, Shiino T, Sato H, Mizuta K, Sakawaki H, Miura T, Naruse TK, Kimura A, Matano T. In vivo virulence of MHC-adapted AIDS virus serially-passaged through MHC-mismatched hosts. PLoS Pathog 2017; 13:e1006638. [PMID: 28931083 PMCID: PMC5624644 DOI: 10.1371/journal.ppat.1006638] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Revised: 10/02/2017] [Accepted: 09/09/2017] [Indexed: 01/02/2023] Open
Abstract
CD8+ T-cell responses exert strong suppressive pressure on HIV replication and select for viral escape mutations. Some of these major histocompatibility complex class I (MHC-I)-associated mutations result in reduction of in vitro viral replicative capacity. While these mutations can revert after viral transmission to MHC-I-disparate hosts, recent studies have suggested that these MHC-I-associated mutations accumulate in populations and make viruses less pathogenic in vitro. Here, we directly show an increase in the in vivo virulence of an MHC-I-adapted virus serially-passaged through MHC-I-mismatched hosts in a macaque AIDS model despite a reduction in in vitro viral fitness. The first passage simian immunodeficiency virus (1pSIV) obtained 1 year after SIVmac239 infection in a macaque possessing a protective MHC-I haplotype 90-120-Ia was transmitted into 90-120-Ia- macaques, whose plasma 1 year post-infection was transmitted into other 90-120-Ia- macaques to obtain the third passage SIV (3pSIV). Most of the 90-120-Ia-associated mutations selected in 1pSIV did not revert even in 3pSIV. 3pSIV showed lower in vitro viral fitness but induced persistent viremia in 90-120-Ia- macaques. Remarkably, 3pSIV infection in 90-120-Ia+ macaques resulted in significantly higher viral loads and reduced survival compared to wild-type SIVmac239. These results indicate that MHC-I-adapted SIVs serially-transmitted through MHC-I-mismatched hosts can have higher virulence in MHC-I-matched hosts despite their lower in vitro viral fitness. This study suggests that multiply-passaged HIVs could result in loss of HIV-specific CD8+ T cell responses in human populations and the in vivo pathogenic potential of these escaped viruses may be enhanced. CD8+ T-cell responses exert considerable control over replication of HIV and select for viral escape mutations. Recent studies have suggested that these major histocompatibility complex class I (MHC-I)-associated mutations accumulate in populations and make viruses less pathogenic in vitro. Other studies have shown that some of these escape mutations can revert after passage to MHC-I-disparate hosts. In an attempt to reconcile these apparently conflicting results, we serially passaged a virus isolate through MHC-I-mismatched hosts in the macaque AIDS model of simian immunodeficiency virus (SIV) infection. Here we show an increase in the in vivo virulence of an MHC-I-adapted virus despite a reduction in in vitro viral replication capacity. Only a few of the selected escape mutations reverted after transmission to MHC-I-disparate recipients. Results clearly showed that MHC-I-adapted SIVs that have been serially-transmitted through MHC-I-mismatched hosts can have higher in vivo virulence in MHC-I-matched hosts despite their lower in vitro viral fitness. This study suggests that HIVs may become less sensitive to CD8+ T cell responses and could have increased in vivo virulence by adaptation to MHC-I in human populations.
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Affiliation(s)
- Sayuri Seki
- AIDS Research Center, National Institute of Infectious Diseases, Tokyo, Japan
| | - Takushi Nomura
- AIDS Research Center, National Institute of Infectious Diseases, Tokyo, Japan
- Center for AIDS Research, Kumamoto University, Tokyo, Japan
| | - Masako Nishizawa
- AIDS Research Center, National Institute of Infectious Diseases, Tokyo, Japan
| | - Hiroyuki Yamamoto
- AIDS Research Center, National Institute of Infectious Diseases, Tokyo, Japan
| | - Hiroshi Ishii
- AIDS Research Center, National Institute of Infectious Diseases, Tokyo, Japan
| | - Saori Matsuoka
- AIDS Research Center, National Institute of Infectious Diseases, Tokyo, Japan
| | - Teiichiro Shiino
- AIDS Research Center, National Institute of Infectious Diseases, Tokyo, Japan
| | - Hironori Sato
- Pathogen Genomics Center, National Institute of Infectious Diseases, Tokyo, Japan
| | - Kazuta Mizuta
- Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
| | - Hiromi Sakawaki
- Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
| | - Tomoyuki Miura
- Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
| | - Taeko K. Naruse
- Medical Research Institute, Tokyo Medical and Dental University, Tokyo, Japan
| | - Akinori Kimura
- Medical Research Institute, Tokyo Medical and Dental University, Tokyo, Japan
| | - Tetsuro Matano
- AIDS Research Center, National Institute of Infectious Diseases, Tokyo, Japan
- Center for AIDS Research, Kumamoto University, Tokyo, Japan
- The Institute of Medical Science, The University of Tokyo, Tokyo, Japan
- * E-mail:
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111
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Kang CY, Gao Y. Killed whole-HIV vaccine; employing a well established strategy for antiviral vaccines. AIDS Res Ther 2017; 14:47. [PMID: 28893272 PMCID: PMC5594480 DOI: 10.1186/s12981-017-0176-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Accepted: 08/11/2017] [Indexed: 11/12/2022] Open
Abstract
The development of an efficient prophylactic HIV vaccine has been one of the major challenges in infectious disease research during the last three decades. Here, we present a mini review on strategies employed for the development of HIV vaccines with an emphasis on a well-established vaccine technology, the killed whole-virus vaccine approach. Recently, we reported an evaluation of the safety and the immunogenicity of a genetically modified and killed whole-HIV-1 vaccine designated as SAV001 [1]. HIV-1 Clade B NL4-3 was genetically modified by deleting the nef and vpu genes and substituting the coding sequence of the Env signal peptide with that of honeybee melittin to produce an avirulent and replication efficient HIV-1. This genetically modified virus (gmHIV-1 NL4-3 ) was propagated in a human T cell line followed by virus purification and inactivation by aldrithiol-2 and γ-irradiation. We found that SAV001 was well tolerated with no serious adverse events. HIV-1 NL4-3 -specific polymerase chain reaction showed no evidence of vaccine virus replication in participants receiving SAV001 and in human T cells infected in vitro. Furthermore, SAV001 with an adjuvant significantly increased the antibody response to HIV-1 structural proteins. Moreover, antibodies in the plasma from these vaccinations neutralized tier I and tier II of HIV-1 B, A, and D subtypes. These results indicated that the killed whole-HIV vaccine is safe and may trigger appropriate immune responses to prevent HIV infection. Utilization of this killed whole-HIV vaccine strategy may pave the way to develop an effective HIV vaccine.
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MESH Headings
- AIDS Vaccines/administration & dosage
- AIDS Vaccines/adverse effects
- AIDS Vaccines/genetics
- AIDS Vaccines/immunology
- Clinical Trials as Topic
- HIV Antibodies/blood
- HIV Antibodies/immunology
- HIV Infections/immunology
- HIV Infections/prevention & control
- HIV-1/genetics
- HIV-1/immunology
- HIV-1/physiology
- Humans
- Vaccines, Inactivated/administration & dosage
- Vaccines, Inactivated/adverse effects
- Vaccines, Inactivated/genetics
- Vaccines, Inactivated/immunology
- Virus Replication
- env Gene Products, Human Immunodeficiency Virus/genetics
- env Gene Products, Human Immunodeficiency Virus/immunology
- gag Gene Products, Human Immunodeficiency Virus/genetics
- gag Gene Products, Human Immunodeficiency Virus/immunology
- nef Gene Products, Human Immunodeficiency Virus/genetics
- nef Gene Products, Human Immunodeficiency Virus/immunology
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Affiliation(s)
- C. Yong Kang
- Department of Microbiology and Immunology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, ON N6G 2V4 Canada
| | - Yong Gao
- Department of Microbiology and Immunology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, ON N6G 2V4 Canada
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112
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Mujib S, Saiyed A, Fadel S, Bozorgzad A, Aidarus N, Yue FY, Benko E, Kovacs C, Emert-Sedlak LA, Smithgall TE, Ostrowski MA. Pharmacologic HIV-1 Nef blockade promotes CD8 T cell-mediated elimination of latently HIV-1-infected cells in vitro. JCI Insight 2017; 2:93684. [PMID: 28878119 PMCID: PMC5621880 DOI: 10.1172/jci.insight.93684] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Accepted: 07/25/2017] [Indexed: 12/16/2022] Open
Abstract
Eradication of the HIV-1 latent reservoir represents the current paradigm to developing a cure for AIDS. HIV-1 has evolved multiple mechanisms to evade CD8 T cell responses, including HIV-1 Nef-mediated downregulation of MHC-I from the surface of infected cells. Nef transcripts and protein are detectable in samples from aviremic donors, suggesting that Nef expression in latently HIV-1-infected CD4 T cells protects them from immune-mediated clearance. Here, we tested 4 small molecule inhibitors of HIV-1 Nef in an in vitro primary CD4 T cell latency model and measured the ability of autologous ex vivo or HIV-1 peptide-expanded CD8 T cells to recognize and kill latently infected cells as a function of inhibitor treatment. Nef inhibition enhanced cytokine secretion by autologous CD8 T cells against latently HIV-1-infected targets in an IFN-γ release assay. Additionally, CD8 T cell-mediated elimination of latently HIV-1-infected cells was significantly enhanced following Nef blockade, measured as a reduction in the frequency of infected cells and Gag protein in cultures following viral outgrowth assays. We demonstrate for the first time to our knowledge that Nef blockade, in combination with HIV-specific CD8 T cell expansion, might be a feasible strategy to target the HIV-1 latent reservoir that should be tested further in vivo.
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Affiliation(s)
- Shariq Mujib
- Institute of Medical Science (IMS), Department of Medicine, and
| | - Aamir Saiyed
- Department of Immunology, University of Toronto, Toronto, Ontario, Canada
| | - Saleh Fadel
- Department of Immunology, University of Toronto, Toronto, Ontario, Canada
| | - Ardalan Bozorgzad
- Department of Immunology, University of Toronto, Toronto, Ontario, Canada
| | - Nasra Aidarus
- Department of Immunology, University of Toronto, Toronto, Ontario, Canada
| | - Feng Yun Yue
- Department of Immunology, University of Toronto, Toronto, Ontario, Canada
| | - Erika Benko
- Maple Leaf Medical Clinic, Toronto, Ontario, Canada
| | - Colin Kovacs
- Department of Immunology, University of Toronto, Toronto, Ontario, Canada
- Maple Leaf Medical Clinic, Toronto, Ontario, Canada
| | - Lori A. Emert-Sedlak
- Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Thomas E. Smithgall
- Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Mario A. Ostrowski
- Institute of Medical Science (IMS), Department of Medicine, and
- Department of Immunology, University of Toronto, Toronto, Ontario, Canada
- Keenan Research Centre for Biomedical Science of St. Michael’s Hospital, Toronto, Ontario, Canada
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113
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The Potency of Nef-Mediated SERINC5 Antagonism Correlates with the Prevalence of Primate Lentiviruses in the Wild. Cell Host Microbe 2017; 20:381-391. [PMID: 27631701 DOI: 10.1016/j.chom.2016.08.004] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Revised: 07/22/2016] [Accepted: 08/15/2016] [Indexed: 12/20/2022]
Abstract
The cellular factor serine incorporator 5 (SERINC5) impairs HIV-1 infectivity but is antagonized by the viral Nef protein. We analyzed the anti-SERINC5 activity of Nef proteins across primate lentiviruses and examined whether SERINC5 represents a barrier to cross-species transmissions and/or within-species viral spread. HIV-1, HIV-2, and SIV Nefs counteract human, ape, monkey, and murine SERINC5 orthologs with similar potency. However, HIV-1 Nefs are more active against SERINC5 than HIV-2 Nefs, and chimpanzee SIV (SIVcpz) Nefs are more potent than those of their monkey precursors. Additionally, Nefs of HIV and most SIVs rely on the dileucine motif in the C-terminal loop for anti-SERINC5 activity, while the Nef from colobus SIV (SIVcol) evolved different inhibitory mechanisms. We also found a significant correlation between anti-SERINC5 potency and the SIV prevalence in the respective ape and monkey species. Thus, Nef-mediated SERINC5 antagonism may determine the ability of primate lentiviruses to spread within natural hosts.
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114
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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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115
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Pužar Dominkuš P, Ferdin J, Plemenitaš A, Peterlin BM, Lenassi M. Nef is secreted in exosomes from Nef.GFP-expressing and HIV-1-infected human astrocytes. J Neurovirol 2017; 23:713-724. [PMID: 28762184 DOI: 10.1007/s13365-017-0552-x] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Revised: 06/16/2017] [Accepted: 07/10/2017] [Indexed: 12/16/2022]
Abstract
HIV-1 infection of the central nervous system causes HIV-associated neurocognitive disorders, even in aviremic patients. Although astrocyte malfunction was associated to these disorders, their implication is overshadowed by contributions of microglia and macrophages. Astrocytes are infected with HIV-1 in vivo and express a relevant amount of viral protein Nef. Nef was shown to stimulate its own release in exosomes from diverse cell types, which in turn have damaging effects on neighboring cells. Using immunoblotting and electron microscopy, we showed that human astrocytes expressing Nef.GFP similarly release Nef in exosomes. Importantly, Nef.GFP expression increases the secretion of exosomes from human astrocytes up to 5.5-fold, as determined by total protein content and nanoparticle tracking analysis. Protein analysis of exosomes and viruses separated on iodixanol gradient further showed that native or pseudotyped HIV-1-infected human astrocytes release exosomes, which contain Nef. Our results provide the basis for future studies of the damaging role of Nef-exosomes produced by HIV-infected astrocytes on the central nervous system.
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Affiliation(s)
- Pia Pužar Dominkuš
- Institute of Biochemistry, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Jana Ferdin
- Institute of Biochemistry, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Ana Plemenitaš
- Institute of Biochemistry, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Boris Matija Peterlin
- Institute of Biochemistry, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia.,Departments of Medicine, Microbiology and Immunology, University of California, San Francisco, San Francisco, California, USA
| | - Metka Lenassi
- Institute of Biochemistry, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia.
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116
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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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117
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Cohen J, Torres C. HIV-associated cellular senescence: A contributor to accelerated aging. Ageing Res Rev 2017; 36:117-124. [PMID: 28017881 DOI: 10.1016/j.arr.2016.12.004] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Revised: 10/28/2016] [Accepted: 12/12/2016] [Indexed: 01/15/2023]
Abstract
Due to the advent of antiretroviral therapy HIV is no longer a terminal disease and the HIV infected patients are becoming increasingly older. While this is a major success, with increasing age comes an increased risk for disease. The age-related comorbidities that HIV infected patients experience suggest that they suffer from accelerated aging. One possible contributor to this accelerated aging is cellular senescence, an age-associated response that can occur prematurely in response to stress, and that is emerging as a contributor to disease and aging. HIV patients experience several stressors such as the virus itself, antiretroviral drugs and to a lesser extent, substance abuse that can induce cellular senescence. This review summarizes the current knowledge of senescence induction in response to these stressors and their relation to the comorbidities in HIV patients. Cellular senescence may be a possible therapeutic target for these comorbidities.
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118
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Trautz B, Wiedemann H, Lüchtenborg C, Pierini V, Kranich J, Glass B, Kräusslich HG, Brocker T, Pizzato M, Ruggieri A, Brügger B, Fackler OT. The host-cell restriction factor SERINC5 restricts HIV-1 infectivity without altering the lipid composition and organization of viral particles. J Biol Chem 2017; 292:13702-13713. [PMID: 28659343 DOI: 10.1074/jbc.m117.797332] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Revised: 06/21/2017] [Indexed: 12/14/2022] Open
Abstract
The host-cell restriction factor SERINC5 potently suppresses the infectivity of HIV, type 1 (HIV-1) particles, and is counteracted by the viral pathogenesis factor Nef. However, the molecular mechanism by which SERINC5 restricts HIV-1 particle infectivity is still unclear. Because SERINC proteins have been suggested to facilitate the incorporation of serine during the biosynthesis of membrane lipids and because lipid composition of HIV particles is a major determinant of the infectious potential of the particles, we tested whether SERINC5-mediated restriction of HIV particle infectivity involves alterations of membrane lipid composition. We produced and purified HIV-1 particles from SERINC5293T cells with very low endogenous SERINC5 levels under conditions in which ectopically expressed SERINC5 restricts HIV-1 infectivity and is antagonized by Nef and analyzed both virions and producer cells with quantitative lipid MS. SERINC5 restriction and Nef antagonism were not associated with significant alterations in steady-state lipid composition of producer cells and HIV particles. Sphingosine metabolism kinetics were also unaltered by SERINC5 expression. Moreover, the levels of phosphatidylserine on the surface of HIV-1 particles, which may trigger uptake into non-productive internalization pathways in target cells, did not change upon expression of SERINC5 or Nef. Finally, saturating the phosphatidylserine-binding sites on HIV target cells did not affect SERINC5 restriction or Nef antagonism. These results demonstrate that the restriction of HIV-1 particle infectivity by SERINC5 does not depend on alterations in lipid composition and organization of HIV-1 particles and suggest that channeling serine into lipid biosynthesis may not be a cardinal cellular function of SERINC5.
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Affiliation(s)
- Birthe Trautz
- From the Department of Infectious Diseases, Integrative Virology, and
| | - Hannah Wiedemann
- the Heidelberg University Biochemistry Center, INF 328, 69120 Heidelberg, Germany
| | | | - Virginia Pierini
- From the Department of Infectious Diseases, Integrative Virology, and
| | - Jan Kranich
- the Institute for Immunology, Ludwig-Maximilians-Universität München, Groβhardener Straße 9, 82152 Planegg-Martinsried, Germany
| | - Bärbel Glass
- Department of Infectious Diseases, Virology, University Hospital Heidelberg, INF 324, 69120 Heidelberg, Germany
| | - Hans-Georg Kräusslich
- Department of Infectious Diseases, Virology, University Hospital Heidelberg, INF 324, 69120 Heidelberg, Germany
| | - Thomas Brocker
- the Institute for Immunology, Ludwig-Maximilians-Universität München, Groβhardener Straße 9, 82152 Planegg-Martinsried, Germany
| | - Massimo Pizzato
- the University of Trento, Centre for Integrative Biology, 38122 Trento, Italy, and
| | - Alessia Ruggieri
- the Department of Infectious Diseases, Molecular Virology, University Hospital Heidelberg, INF 345, 69120 Heidelberg, Germany
| | - Britta Brügger
- the Heidelberg University Biochemistry Center, INF 328, 69120 Heidelberg, Germany,
| | - Oliver T Fackler
- From the Department of Infectious Diseases, Integrative Virology, and
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119
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Jacob RA, Johnson AL, Pawlak EN, Dirk BS, Van Nynatten LR, Haeryfar SMM, Dikeakos JD. The interaction between HIV-1 Nef and adaptor protein-2 reduces Nef-mediated CD4 + T cell apoptosis. Virology 2017; 509:1-10. [PMID: 28577469 DOI: 10.1016/j.virol.2017.05.018] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Revised: 05/24/2017] [Accepted: 05/25/2017] [Indexed: 02/07/2023]
Abstract
Acquired Immune Deficiency Syndrome is characterized by a decline in CD4+ T cells. Here, we elucidated the mechanism underlying apoptosis in Human Immunodeficiency Virus-1 (HIV-1) infection by examining host apoptotic pathways hijacked by the HIV-1 Nef protein in the CD4+ T-cell line Sup-T1. Using a panel of Nef mutants unable to bind specific host proteins we uncovered that Nef generates pro- and anti-apoptotic signals. Apoptosis increased upon mutating the motifs involved in the interaction of Nef:AP-1 (NefM20A or NefEEEE62-65AAAA) or Nef:AP-2 (NefLL164/165AA), implying these interactions limit Nef-mediated apoptosis. In contrast, disrupting the Nef:PAK2 interaction motifs (NefH89A or NefF191A) reduced apoptosis. To validate further, apoptosis was measured after short-hairpin RNA knock-down of AP-1, AP-2 and PAK2. AP-2α depletion enhanced apoptosis, demonstrating that disrupting the Nef:AP-2α interaction limits Nef-mediated apoptosis. Collectively, we describe a mechanism by which HIV-1 regulates cell survival and demonstrate the consequence of interfering with Nef:host protein interactions.
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Affiliation(s)
- Rajesh Abraham Jacob
- Department of Microbiology and Immunology, The University of Western Ontario, Schulich School of Medicine and Dentistry, London, Ontario, Canada
| | - Aaron L Johnson
- Department of Microbiology and Immunology, The University of Western Ontario, Schulich School of Medicine and Dentistry, London, Ontario, Canada
| | - Emily N Pawlak
- Department of Microbiology and Immunology, The University of Western Ontario, Schulich School of Medicine and Dentistry, London, Ontario, Canada
| | - Brennan S Dirk
- Department of Microbiology and Immunology, The University of Western Ontario, Schulich School of Medicine and Dentistry, London, Ontario, Canada
| | - Logan R Van Nynatten
- Department of Microbiology and Immunology, The University of Western Ontario, Schulich School of Medicine and Dentistry, London, Ontario, Canada
| | - S M Mansour Haeryfar
- Department of Microbiology and Immunology, The University of Western Ontario, Schulich School of Medicine and Dentistry, London, Ontario, Canada
| | - Jimmy D Dikeakos
- Department of Microbiology and Immunology, The University of Western Ontario, Schulich School of Medicine and Dentistry, London, Ontario, Canada.
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120
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Distinct transcriptome profiles of Gag-specific CD8+ T cells temporally correlated with the protection elicited by SIVΔnef live attenuated vaccine. PLoS One 2017; 12:e0173929. [PMID: 28333940 PMCID: PMC5363825 DOI: 10.1371/journal.pone.0173929] [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: 11/06/2016] [Accepted: 02/27/2017] [Indexed: 12/21/2022] Open
Abstract
The live attenuated vaccine (LAV) SIVmac239Δnef (SIVΔnef) confers the best protection among all the vaccine modalities tested in rhesus macaque model of HIV-1 infection. This vaccine has a unique feature of time-dependent protection: macaques are not protected at 3–5 weeks post vaccination (WPV), whereas immune protection emerges between 15 and 20 WPV. Although the exact mechanisms of the time-dependent protection remain incompletely understood, studies suggested that both cellular and humoral immunities contribute to this time-dependent protection. To further elucidate the mechanisms of protection induced by SIVΔnef, we longitudinally compared the global gene expression profiles of SIV Gag-CM9+ CD8+ (Gag-specific CD8+) T cells from peripheral blood of Mamu-A*01+ rhesus macaques at 3 and 20 WPV using rhesus microarray. We found that gene expression profiles of Gag-specific CD8+ T cells at 20 WPV are qualitatively different from those at 3 WPV. At 20 WPV, the most significant transcriptional changes of Gag-specific CD8+ T cells were genes involved in TCR signaling, differentiation and maturation toward central memory cells, with increased expression of CCR7, TCRα, TCRβ, CD28 and decreased expression of CTLA-4, IFN-γ, RANTES, granzyme A and B. Our study suggests that a higher quality of SIV-specific CD8+ T cells elicited by SIVΔnef over time contributes to the maturation of time-dependent protection.
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121
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Effect of HIV-1 Env on SERINC5 Antagonism. J Virol 2017; 91:JVI.02214-16. [PMID: 27928004 DOI: 10.1128/jvi.02214-16] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Accepted: 11/28/2016] [Indexed: 11/20/2022] Open
Abstract
SERINC5 is able to restrict HIV-1 infection by drastically impairing the infectivity of viral particles. Studies have shown that the HIV-1 Nef protein counters SERINC5 through downregulating SERINC5 from the cell surface and preventing the virion incorporation of SERINC5. In addition, the Env proteins of some HIV-1 strains can also overcome SERINC5 inhibition. However, it is unclear how HIV-1 Env does so and why HIV-1 has two mechanisms to resist SERINC5 inhibition. The results of this study show that neither Env nor Nef prevents high levels of ectopic SERINC5 from being incorporated into HIV-1 particles, except that Env, but not Nef, is able to resist inhibition by virion-associated SERINC5. Testing of a panel of HIV-1 Env proteins from different subtypes revealed a high frequency of SERINC5-resistant Envs. Interestingly, although the SERINC5-bearing viruses were not inhibited by SERINC5 itself, they became more sensitive to the CCR5 inhibitor maraviroc and some neutralizing antibodies than the SERINC5-free viruses, which suggests a possible influence of SERINC5 on Env function. We conclude that HIV-1 Env is able to overcome SERINC5 without preventing SERINC5 virion incorporation. IMPORTANCE HIV-1 Nef is known to enhance the infectivity of HIV-1 particles and to contribute to the maintenance of high viral loads in patients. However, the underlying molecular mechanism remained elusive until the recent discovery of the antiviral activity of SERINC5. SERINC5 profoundly inhibits HIV-1 but is antagonized by Nef, which prevents the incorporation of SERINC5 into viral particles. Here, we show that HIV-1 Env, but not Nef, is able to resist high levels of SERINC5 without excluding SERINC5 from incorporation into viral particles. However, the virion-associated SERINC5 renders HIV-1 more sensitive to some broadly neutralizing antibodies. It is possible that, under the pressure of some neutralizing antibodies in vivo, HIV-1 needs Nef to remove SERINC5 from viral particles, even though viral Env is able to resist virion-associated SERINC5.
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122
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Qin J, Lu C. Infection of KSHV and Interaction with HIV: The Bad Romance. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 1018:237-251. [PMID: 29052142 DOI: 10.1007/978-981-10-5765-6_15] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Kaposi's sarcoma-associated herpesvirus (KSHV), namely, human herpesvirus 8 (HHV-8), is considered as the pathogen of Kaposi's sarcoma (KS), the most frequent cancer in untreated HIV-infected individuals. Patients infected with HIV have a much higher possibility developing KS than average individual. Researchers have found that HIV, which functions as a cofactor of KS, contributes a lot to the development of KS. In this article, we will give a brief introduction of KS and KSHV and how the interaction between KSHV and HIV contributes to the development of KS. Also we will take a glance at the development of treatment in KS, especially AIDS-KS.
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Affiliation(s)
- Jie Qin
- Key Laboratory of Pathogen Biology (Jiangsu Province), Nanjing Medical University, Nanjing, People's Republic of China.,Department of Microbiology, Nanjing Medical University, Nanjing, 210029, People's Republic of China
| | - Chun Lu
- Key Laboratory of Pathogen Biology (Jiangsu Province), Nanjing Medical University, Nanjing, People's Republic of China. .,Department of Microbiology, Nanjing Medical University, Nanjing, 210029, People's Republic of China.
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Shu ST, Emert-Sedlak LA, Smithgall TE. Cell-based Fluorescence Complementation Reveals a Role for HIV-1 Nef Protein Dimerization in AP-2 Adaptor Recruitment and CD4 Co-receptor Down-regulation. J Biol Chem 2016; 292:2670-2678. [PMID: 28031466 DOI: 10.1074/jbc.m116.770016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Revised: 12/21/2016] [Indexed: 02/03/2023] Open
Abstract
The HIV-1 Nef accessory factor enhances viral infectivity, immune evasion, and AIDS progression. Nef triggers rapid down-regulation of CD4 via the endocytic adaptor protein 2 (AP-2) complex, a process linked to enhanced viral infectivity and immune escape. Here, we describe a bimolecular fluorescence complementation (BiFC) assay to visualize the interaction of Nef with AP-2 and CD4 in living cells. Interacting protein pairs were fused to complementary non-fluorescent fragments of YFP and co-expressed in 293T cells. Nef interactions with both CD4 and AP-2 resulted in complementation of YFP and a bright fluorescent signal by confocal microcopy that localized to the cell periphery. Co-expression of the AP-2 α subunit enhanced the Nef·AP-2 σ2 subunit BiFC signal and vice versa, suggesting that the AP-2 α-σ2 hemicomplex interacts cooperatively with Nef. Mutagenesis of Nef amino acids Arg-134, Glu-174, and Asp-175, which stabilize Nef for AP-2 α-σ2 binding in a recent co-crystal structure, substantially reduced AP-2 interaction without affecting CD4 binding. A dimerization-defective mutant of Nef failed to interact with either CD4 or AP-2 in the BiFC assay, indicating that Nef quaternary structure is required for CD4 and AP-2 recruitment as well as CD4 down-regulation. A small molecule previously shown to bind the Nef dimerization interface also reduced Nef interactions with AP-2 and CD4 and restored CD4 expression to the surface of HIV-infected cells. Our findings provide a mechanistic explanation for previous observations that dimerization-defective Nef mutants fail to down-regulate CD4 and validate the Nef dimerization interface as a target site for antiretroviral drug development.
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Affiliation(s)
- Sherry T Shu
- From the Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15219
| | - Lori A Emert-Sedlak
- From the Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15219
| | - Thomas E Smithgall
- From the Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15219
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Goffinet C. Cellular Antiviral Factors that Target Particle Infectivity of HIV-1. Curr HIV Res 2016; 14:211-6. [PMID: 26674651 PMCID: PMC5403965 DOI: 10.2174/1570162x14666151216145521] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Revised: 10/30/2015] [Accepted: 12/14/2015] [Indexed: 11/22/2022]
Abstract
Background: In the past decade, the identification and characterization of antiviral genes with the ability to interfere with virus replication has established cell-intrinsic innate immunity as a third line of antiviral defense in addition to adaptive and classical innate immunity. Understanding how cellular factors have evolved to inhibit HIV-1 reveals particularly vulnerable points of the viral replication cycle. Many, but not all, antiviral proteins share type I interferon-upregulated expression and sensitivity to viral counteraction or evasion measures. Whereas well-established restriction factors interfere with early post-entry steps and release of HIV-1, recent research has revealed a diverse set of proteins that reduce the infectious quality of released particles using individual, to date poorly understood modes of action. These include induction of paucity of mature glycoproteins in nascent virions or self-incorporation into the virus particle, resulting in poor infectiousness of the virion and impaired spread of the infection. Conclusion: A better understanding of these newly discovered antiviral factors may open new avenues towards the design of drugs that repress the spread of viruses whose genomes have already integrated.
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Affiliation(s)
- Christine Goffinet
- Institute of Experimental Virology, TWINCORE Centre for Experimental and Clinical Infection Research, a joint venture between the Hannover Medical School (MHH) and the Helmholtz Centre for Infection Research (HZI), Hannover, Germany.
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125
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Li SX, Barrett BS, Guo K, Santiago ML. Tetherin/BST-2: Restriction Factor or Immunomodulator? Curr HIV Res 2016; 14:235-46. [PMID: 26957198 DOI: 10.2174/1570162x14999160224102752] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Revised: 08/10/2015] [Accepted: 08/11/2015] [Indexed: 11/22/2022]
Abstract
BACKGROUND Cell-mediated immune (CMI) responses are critical for the control of HIV-1 infection and their importance was highlighted by the existence of viral proteins, particularly Vpu and Nef, that antagonize these responses. Pandemic HIV-1 Vpu counteracts Tetherin/BST-2, a host factor that could prevent the release of HIV-1 virions by tethering virions on the cell surface, but a link between Tetherin and HIV-1 CMI responses has not yet been demonstrated in vivo. In vitro, the virological and immunological impact of Tetherin-mediated accumulation of virions ranged from enhanced or diminished cell-to-cell spread to enhanced recognition by virus-specific antibodies for natural killer cellmediated lysis. However, Tetherin-restricted virions could be internalized through an endocytosis motif in the Tetherin cytoplasmic tail. METHODS Given the uncertainties on which in vitro results manifest in vivo and the dearth of knowledge on how Tetherin influences retroviral immunity, in vivo retrovirus infections in mice encoding wild-type, null and endocytosis-defective Tetherin were performed. Here, we review and highlight the results from these in vivo studies. RESULTS Current data suggests that endocytosis-defective Tetherin functions as a potent innate restriction factor. By contrast, endocytosis-competent Tetherin, the form found in most mammals including humans and the form counteracted by HIV-1 Vpu, was linked to stronger CMI responses in mice. CONCLUSION We propose that the main role of endocytosis-competent Tetherin is not to directly restrict retroviral replication, but to promote a more effective CMI response against retroviruses.
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Affiliation(s)
| | | | | | - Mario L Santiago
- Division of Infectious Diseases, University of Colorado Denver, Mail Stop B-168, 12700 E 19th Avenue, Aurora, CO 80045, USA.
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126
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Tavares LA, da Silva EML, da Silva-Januário ME, Januário YC, de Cavalho JV, Czernisz ÉS, Mardones GA, daSilva LLP. CD4 downregulation by the HIV-1 protein Nef reveals distinct roles for the γ1 and γ2 subunits of the AP-1 complex in protein trafficking. J Cell Sci 2016; 130:429-443. [PMID: 27909244 DOI: 10.1242/jcs.192104] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Accepted: 11/16/2016] [Indexed: 12/20/2022] Open
Abstract
The HIV accessory protein Nef is a major determinant of viral pathogenesis that facilitates viral particle release, prevents viral antigen presentation and increases infectivity of new virus particles. These functions of Nef involve its ability to remove specific host proteins from the surface of infected cells, including the CD4 receptor. Nef binds to the adaptor protein 2 (AP-2) and CD4 in clathrin-coated pits, forcing CD4 internalization and its subsequent targeting to lysosomes. Herein, we report that this lysosomal targeting requires a variant of AP-1 containing isoform 2 of γ-adaptin (AP1G2, hereafter γ2). Depletion of the γ2 or μ1A (AP1M1) subunits of AP-1, but not of γ1 (AP1G1), precludes Nef-mediated lysosomal degradation of CD4. In γ2-depleted cells, CD4 internalized by Nef accumulates in early endosomes and this alleviates CD4 removal from the cell surface. Depletion of γ2 also hinders EGFR-EGF-complex targeting to lysosomes, an effect that is not observed upon γ1 depletion. Taken together, our data provide evidence that the presence of γ1 or γ2 subunits delineates two distinct variants of AP-1 complexes, with different functions in protein sorting.
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Affiliation(s)
- Lucas A Tavares
- Department of Cell and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo 14049-900, Brazil
| | - Eulália M L da Silva
- Department of Cell and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo 14049-900, Brazil
| | - Mara E da Silva-Januário
- Department of Cell and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo 14049-900, Brazil
| | - Yunan C Januário
- Department of Cell and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo 14049-900, Brazil
| | - Julianne V de Cavalho
- Department of Cell and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo 14049-900, Brazil
| | - Érika S Czernisz
- Department of Cell and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo 14049-900, Brazil
| | - Gonzalo A Mardones
- Department of Physiology, School of Medicine, and Center for Interdisciplinary Studies of the Nervous System (CISNe), Universidad Austral de Chile, Valdivia 5110566, Chile
| | - Luis L P daSilva
- Department of Cell and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo 14049-900, Brazil
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127
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The Antagonism of HIV-1 Nef to SERINC5 Particle Infectivity Restriction Involves the Counteraction of Virion-Associated Pools of the Restriction Factor. J Virol 2016; 90:10915-10927. [PMID: 27681140 DOI: 10.1128/jvi.01246-16] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Accepted: 09/21/2016] [Indexed: 11/20/2022] Open
Abstract
SERINC3 (serine incorporator 3) and SERINC5 are recently identified host cell inhibitors of HIV-1 particle infectivity that are counteracted by the viral pathogenesis factor Nef. Here we confirm that HIV-1 Nef, but not HIV-1 Vpu, antagonizes the particle infectivity restriction of SERINC5. SERINC5 antagonism occurred in parallel with other Nef activities, including cell surface receptor downregulation, trans-Golgi network targeting of Lck, and inhibition of host cell actin dynamics. Interaction motifs with host cell endocytic machinery and the Nef-associated kinase complex, as well as CD4 cytoplasmic tail/HIV-1 protease, were identified as essential Nef determinants for SERINC5 antagonism. Characterization of antagonism-deficient Nef mutants revealed that counteraction of SERINC5 occurs in the absence of retargeting of the restriction factor to intracellular compartments and reduction of SERINC5 cell surface density is insufficient for antagonism. Consistent with virion incorporation of SERINC5 being a prerequisite for its antiviral activity, the infectivity of HIV-1 particles produced in the absence of a SERINC5 antagonist decreased with increasing amounts of virion SERINC5. At low levels of SERINC5 expression, enhancement of virion infectivity by Nef was associated with reduced virion incorporation of SERINC5 and antagonism-defective Nef mutants failed to exclude SERINC5 from virions. However, at elevated levels of SERINC5 expression, Nef maintained infectious HIV particles, despite significant virion incorporation of the restriction factor. These results suggest that in addition to virion exclusion, Nef employs a cryptic mechanism to antagonize virion-associated SERINC5. The involvement of common determinants suggests that the antagonism of Nef to SERINC5 and the downregulation of cell surface CD4 by Nef involve related molecular mechanisms. IMPORTANCE HIV-1 Nef critically determines virus spread and disease progression in infected individuals by incompletely defined mechanisms. SERINC3 and SERINC5 were recently identified as potent inhibitors of HIV particle infectivity whose antiviral activity is antagonized by HIV-1 Nef. To address the mechanism of SERINC5 antagonism, we identified four molecular determinants of Nef antagonism that are all linked to the mechanism by which Nef downregulates cell surface CD4. Functional characterization of these mutants revealed that endosomal targeting and cell surface downregulation of SERINC5 are dispensable and insufficient for antagonism, respectively. In contrast, virion exclusion and antagonism of SERINC5 were correlated; however, Nef was also able to enhance the infectivity of virions that incorporated robust levels of SERINC5. These results suggest that the antagonism of HIV-1 Nef to SERINC5 restriction of virion infectivity is mediated by a dual mechanism that is related to CD4 downregulation.
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128
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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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129
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Lopker MJ, Del Prete GQ, Estes JD, Li H, Reid C, Newman L, Lipkey L, Camus C, Easlick JL, Wang S, Decker JM, Bar KJ, Learn G, Pal R, Weiss DE, Hahn BH, Lifson JD, Shaw GM, Keele BF. Derivation and Characterization of Pathogenic Transmitted/Founder Molecular Clones from Simian Immunodeficiency Virus SIVsmE660 and SIVmac251 following Mucosal Infection. J Virol 2016; 90:8435-53. [PMID: 27412591 PMCID: PMC5021393 DOI: 10.1128/jvi.00718-16] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Accepted: 07/06/2016] [Indexed: 12/31/2022] Open
Abstract
UNLABELLED Currently available simian immunodeficiency virus (SIV) infectious molecular clones (IMCs) and isolates used in nonhuman primate (NHP) models of AIDS were originally derived from infected macaques during chronic infection or end stage disease and may not authentically recapitulate features of transmitted/founder (T/F) genomes that are of particular interest in transmission, pathogenesis, prevention, and treatment studies. We therefore generated and characterized T/F IMCs from genetically and biologically heterogeneous challenge stocks of SIVmac251 and SIVsmE660. Single-genome amplification (SGA) was used to identify full-length T/F genomes present in plasma during acute infection resulting from atraumatic rectal inoculation of Indian rhesus macaques with low doses of SIVmac251 or SIVsmE660. All 8 T/F clones yielded viruses that were infectious and replication competent in vitro, with replication kinetics similar to those of the widely used chronic-infection-derived IMCs SIVmac239 and SIVsmE543. Phenotypically, the new T/F virus strains exhibited a range of neutralization sensitivity profiles. Four T/F virus strains were inoculated into rhesus macaques, and each exhibited typical SIV replication kinetics. The SIVsm T/F viruses were sensitive to TRIM5α restriction. All T/F viruses were pathogenic in rhesus macaques, resulting in progressive CD4(+) T cell loss in gastrointestinal tissues, peripheral blood, and lymphatic tissues. The animals developed pathological immune activation; lymphoid tissue damage, including fibrosis; and clinically significant immunodeficiency leading to AIDS-defining clinical endpoints. These T/F clones represent a new molecular platform for the analysis of virus transmission and immunopathogenesis and for the generation of novel "bar-coded" challenge viruses and next-generation simian-human immunodeficiency viruses that may advance the HIV/AIDS vaccine agenda. IMPORTANCE Nonhuman primate research has relied on only a few infectious molecular clones for a myriad of diverse research projects, including pathogenesis, preclinical vaccine evaluations, transmission, and host-versus-pathogen interactions. With new data suggesting a selected phenotype of the virus that causes infection (i.e., the transmitted/founder virus), we sought to generate and characterize infectious molecular clones from two widely used simian immunodeficiency virus lineages (SIVmac251 and SIVsmE660). Although the exact requirements necessary to be a T/F virus are not yet fully understood, we generated cloned viruses with all the necessary characteristic of a successful T/F virus. The cloned viruses revealed typical acute and set point viral-load dynamics with pathological immune activation, lymphoid tissue damage progressing to significant immunodeficiency, and AIDS-defining clinical endpoints in some animals. These T/F clones represent a new molecular platform for studies requiring authentic T/F viruses.
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Affiliation(s)
| | - Gregory Q Del Prete
- AIDS and Cancer Virus Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, Maryland, USA
| | - Jacob D Estes
- AIDS and Cancer Virus Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, Maryland, USA
| | - Hui Li
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Carolyn Reid
- AIDS and Cancer Virus Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, Maryland, USA
| | - Laura Newman
- AIDS and Cancer Virus Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, Maryland, USA
| | - Leslie Lipkey
- AIDS and Cancer Virus Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, Maryland, USA
| | - Celine Camus
- AIDS and Cancer Virus Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, Maryland, USA
| | | | - Shuyi Wang
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Julie M Decker
- University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Katharine J Bar
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Gerald Learn
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Ranajit Pal
- Advanced BioScience Laboratories, Inc., Rockville, Maryland, USA
| | | | - Beatrice H Hahn
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Jeffrey D Lifson
- AIDS and Cancer Virus Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, Maryland, USA
| | - George M Shaw
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Brandon F Keele
- AIDS and Cancer Virus Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, Maryland, USA
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130
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Manzourolajdad A, Gonzalez M, Spouge JL. Changes in the Plasticity of HIV-1 Nef RNA during the Evolution of the North American Epidemic. PLoS One 2016; 11:e0163688. [PMID: 27685447 PMCID: PMC5042412 DOI: 10.1371/journal.pone.0163688] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Accepted: 09/13/2016] [Indexed: 02/04/2023] Open
Abstract
Because of a high mutation rate, HIV exists as a viral swarm of many sequence variants evolving under various selective pressures from the human immune system. Although the Nef gene codes for the most immunogenic of HIV accessory proteins, which alone makes it of great interest to HIV research, it also encodes an RNA structure, whose contribution to HIV virulence has been largely unexplored. Nef RNA helps HIV escape RNA interference (RNAi) through nucleotide changes and alternative folding. This study examines Historic and Modern Datasets of patient HIV-1 Nef sequences during the evolution of the North American epidemic for local changes in RNA plasticity. By definition, RNA plasticity refers to an RNA molecule’s ability to take alternative folds (i.e., alternative conformations). Our most important finding is that an evolutionarily conserved region of the HIV-1 Nef gene, which we denote by R2, recently underwent a statistically significant increase in its RNA plasticity. Thus, our results indicate that Modern Nef R2 typically accommodates an alternative fold more readily than Historic Nef R2. Moreover, the increase in RNA plasticity resides mostly in synonymous nucleotide changes, which cannot be a response to selective pressures on the Nef protein. R2 may therefore be of interest in the development of antiviral RNAi therapies.
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Affiliation(s)
- Amirhossein Manzourolajdad
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, Maryland, United States of America
- * E-mail:
| | - Mileidy Gonzalez
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, Maryland, United States of America
| | - John L. Spouge
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, Maryland, United States of America
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131
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D186/D190 is an allele-dependent determinant of HIV-1 Nef function. Virology 2016; 498:44-56. [PMID: 27560372 DOI: 10.1016/j.virol.2016.08.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2016] [Revised: 08/12/2016] [Accepted: 08/13/2016] [Indexed: 01/23/2023]
Abstract
The HIV-1 pathogenesis factor Nef interacts with numerous ligands to affect cellular vesicular transport, signal transduction and cytoskeletal dynamics. While most Nef functions depend on multivalent protein interaction motifs, disrupting actin dynamics requires a motif that specifically recruits the host kinase PAK2. An adjacent aspartate was recently predicted to mediate Nef-β-catenin interactions. We report here that β-catenin can be co-immunoprecipitated with Nef.GFP from Jurkat T cell lysates. This association is conserved among lentiviral Nef proteins but does not involve classical Nef protein interaction motifs, including the critical aspartate. While aspartate-to-alanine mutations impaired cell surface receptor downregulation and interference with actin dynamics and cell motility by HIV-1 NA7 Nef, analogous mutations did not affect HIV-1 SF2 Nef function. These allelic differences were determined by a proximal lysine/arginine polymorphism. These results emphasize differences between Nef alleles regarding the functional role of individual residues and underscore the need for allele-specific structure-function analyses.
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132
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Pyeon D, Timani KA, Gulraiz F, He JJ, Park IW. Function of ubiquitin (Ub) specific protease 15 (USP15) in HIV-1 replication and viral protein degradation. Virus Res 2016; 223:161-9. [PMID: 27460547 DOI: 10.1016/j.virusres.2016.07.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Revised: 07/11/2016] [Accepted: 07/18/2016] [Indexed: 12/23/2022]
Abstract
HIV-1 Nef is necessary and may be sufficient for HIV-1-associated AIDS pathogenicity, in that knockout of Nef alone can protect HIV-infected patients from AIDS. We therefore investigated the feasibility of physical knockout of Nef, using the host ubiquitin proteasome system in HIV-1-infected cells. Our co-immunoprecipitation analysis demonstrated that Nef interacted with ubiquitin specific protease 15 (USP15), and that USP15, which is known to stabilize cellular proteins, degraded Nef. Nef could also cause decay of USP15, although Nef-mediated degradation of USP15 was weaker than USP15-mediated Nef degradation. Direct interaction between Nef and USP15 was essential for the observed reciprocal decay of the proteins. Further, USP15 degraded not only Nef but also HIV-1 structural protein, Gag, thereby substantially inhibiting HIV-1 replication. However, Gag did not degrade USP15, indicating that the Nef and USP15 complex, in distinction to other viral proteins, play an integral role in coordinating viral protein degradation and hence HIV-1 replication. Moreover, Nef and USP15 globally suppressed ubiquitylation of cellular proteins, indicating that these proteins are major determinants for the stability of cellular as well as viral proteins. Taken together, these data indicate that Nef and USP15 are vital in regulating degradation of viral and cellular proteins and thus HIV-1 replication, and specific degradation of viral, not cellular proteins, by USP15 points to USP15 as a candidate therapeutic agent to combat AIDS by eliminating viral proteins from the infected cells via USP15-mediated proteosomal degradation.
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Affiliation(s)
- Dohun Pyeon
- Departments of Immunology and Microbiology, and Medicine, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Khalid Amine Timani
- Department of Cell Biology and Immunology, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
| | - Fahad Gulraiz
- Department of Cell Biology and Immunology, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
| | - Johnny J He
- Department of Cell Biology and Immunology, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
| | - In-Woo Park
- Department of Cell Biology and Immunology, University of North Texas Health Science Center, Fort Worth, TX 76107, USA.
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Garcia-Tellez T, Huot N, Ploquin MJ, Rascle P, Jacquelin B, Müller-Trutwin M. Non-human primates in HIV research: Achievements, limits and alternatives. INFECTION GENETICS AND EVOLUTION 2016; 46:324-332. [PMID: 27469027 DOI: 10.1016/j.meegid.2016.07.012] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Revised: 07/07/2016] [Accepted: 07/12/2016] [Indexed: 12/20/2022]
Abstract
An ideal model for HIV-1 research is still unavailable. However, infection of non-human primates (NHP), such as macaques, with Simian Immunodeficiency Virus (SIV) recapitulates most virological, immunological and clinical hallmarks of HIV infection in humans. It has become the most suitable model to study the mechanisms of transmission and physiopathology of HIV/AIDS. On the other hand, natural hosts of SIV, such as African green monkeys and sooty mangabeys that when infected do not progress to AIDS, represent an excellent model to elucidate the mechanisms involved in the capacity of controlling inflammation and disease progression. The use of NHP-SIV models has indeed enriched our knowledge in the fields of: i) viral transmission and viral reservoirs, ii) early immune responses, iii) host cell-virus interactions in tissues, iv) AIDS pathogenesis, v) virulence factors, vi) prevention and vii) drug development. The possibility to control many variables during experimental SIV infection, together with the resemblance between SIV and HIV infections, make the NHP model the most appropriate, so far, for HIV/AIDS research. Nonetheless, some limitations in using these models have to be considered. Alternative models for HIV/AIDS research, such as humanized mice and recombinant forms of HIV-SIV viruses (SHIV) for NHP infection, have been developed. The improvement of SHIV viruses that mimic even better the natural history of HIV infection and of humanized mice that develop a greater variety of human immune cell lineages, is ongoing. None of these models is perfect, but they allow contributing to the progress in managing or preventing HIV infection.
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Affiliation(s)
- Thalía Garcia-Tellez
- Institut Pasteur, Unité HIV, Inflammation and Persistence. 25-28 Rue du Doctor Roux,75015 Paris, France.
| | - Nicolas Huot
- Institut Pasteur, Unité HIV, Inflammation and Persistence. 25-28 Rue du Doctor Roux,75015 Paris, France; Vaccine Research Institute, Créteil, France.
| | - Mickaël J Ploquin
- Institut Pasteur, Unité HIV, Inflammation and Persistence. 25-28 Rue du Doctor Roux,75015 Paris, France.
| | - Philippe Rascle
- Institut Pasteur, Unité HIV, Inflammation and Persistence. 25-28 Rue du Doctor Roux,75015 Paris, France.
| | - Beatrice Jacquelin
- Institut Pasteur, Unité HIV, Inflammation and Persistence. 25-28 Rue du Doctor Roux,75015 Paris, France.
| | - Michaela Müller-Trutwin
- Institut Pasteur, Unité HIV, Inflammation and Persistence. 25-28 Rue du Doctor Roux,75015 Paris, France; Vaccine Research Institute, Créteil, France.
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134
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Jones AE, Saksela K, Game SM, O'Beirne G, Cook ND. Screening Assay for the Detection of the Protein-Protein Interaction Between HIV-1 Nef Protein and the SH3 Domain of Hck. ACTA ACUST UNITED AC 2016. [DOI: 10.1177/108705719800300105] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The interaction between the Human Immunodeficiency Virus Nef protein (HIV-1 Nef) and the Src Homology Region 3 (SH3) domain of Hck was studied using scintillation proximity assay (SPA). SPA is a quick and sensitive method that does not require a separation step, thus allowing assays to be performed in a homogeneous environment. In contrast to most conventional techniques, SPA may also be used to detect low affinity protein-protein interactions. In this study, the assay was configured using biotinylated Hck SH3 domain expressed both as a GST fusion protein and synthesized chemically in its' native form. Biotinylated Hck protein was immobilized to streptavidin-coated fluoromicrosphere SPA beads and the binding of [3H]Nef was detected by scintillation counting. Analysis of binding yielded an average equilibrium dissociation constant (KD) of 183 ± 30 nM for the interaction in line with reported values by other methods. The data presented demonstrates that using SPA, protein-protein interactions of relatively low affinity can be detected with a high degree of sensitivity and screening studies of inhibitors of these associations could be facilitated by the high sample throughput achievable with SPA.
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Affiliation(s)
- Anne E. Jones
- Nycomed Amersham plc, Cardiff Laboratories, Forest Farm Estate, Whitchurch, CF4 7YT, UK
| | - Kalle Saksela
- Institute of Medical Technology, University of Tampere, P.O. Box 607, Fin-33101, Tampere, Finland
| | - Stephen M. Game
- Nycomed Amersham plc, Cardiff Laboratories, Forest Farm Estate, Whitchurch, CF4 7YT, UK
| | - Gerard O'Beirne
- Nycomed Amersham plc, Cardiff Laboratories, Forest Farm Estate, Whitchurch, CF4 7YT, UK
| | - Neil D. Cook
- Nycomed Amersham plc, Cardiff Laboratories, Forest Farm Estate, Whitchurch, CF4 7YT, UK
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135
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Pereira EA, daSilva LLP. HIV-1 Nef: Taking Control of Protein Trafficking. Traffic 2016; 17:976-96. [PMID: 27161574 DOI: 10.1111/tra.12412] [Citation(s) in RCA: 95] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Revised: 05/05/2016] [Accepted: 05/05/2016] [Indexed: 12/25/2022]
Abstract
The Nef protein of the human immunodeficiency virus is a crucial determinant of viral pathogenesis and disease progression. Nef is abundantly expressed early in infection and is thought to optimize the cellular environment for viral replication. Nef controls expression levels of various cell surface molecules that play important roles in immunity and virus life cycle, by directly interfering with the itinerary of these proteins within the endocytic and late secretory pathways. To exert these functions, Nef physically interacts with host proteins that regulate protein trafficking. In recent years, considerable progress was made in identifying host-cell-interacting partners for Nef, and the molecular machinery used by Nef to interfere with protein trafficking has started to be unraveled. Here, we briefly review the knowledge gained and discuss new findings regarding the mechanisms by which Nef modifies the intracellular trafficking pathways to prevent antigen presentation, facilitate viral particle release and enhance the infectivity of HIV-1 virions.
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Affiliation(s)
- Estela A Pereira
- Department of Cell and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Luis L P daSilva
- Department of Cell and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, SP, Brazil
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136
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Wales TE, Poe JA, Emert-Sedlak L, Morgan CR, Smithgall TE, Engen JR. Hydrogen Exchange Mass Spectrometry of Related Proteins with Divergent Sequences: A Comparative Study of HIV-1 Nef Allelic Variants. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2016; 27:1048-61. [PMID: 27032648 PMCID: PMC4865444 DOI: 10.1007/s13361-016-1365-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Revised: 02/11/2016] [Accepted: 02/12/2016] [Indexed: 05/16/2023]
Abstract
Hydrogen exchange mass spectrometry can be used to compare the conformation and dynamics of proteins that are similar in tertiary structure. If relative deuterium levels are measured, differences in sequence, deuterium forward- and back-exchange, peptide retention time, and protease digestion patterns all complicate the data analysis. We illustrate what can be learned from such data sets by analyzing five variants (Consensus G2E, SF2, NL4-3, ELI, and LTNP4) of the HIV-1 Nef protein, both alone and when bound to the human Hck SH3 domain. Regions with similar sequence could be compared between variants. Although much of the hydrogen exchange features were preserved across the five proteins, the kinetics of Nef binding to Hck SH3 were not the same. These observations may be related to biological function, particularly for ELI Nef where we also observed an impaired ability to downregulate CD4 surface presentation. The data illustrate some of the caveats that must be considered for comparison experiments and provide a framework for investigations of other protein relatives, families, and superfamilies with HX MS. Graphical Abstract ᅟ.
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Affiliation(s)
- Thomas E Wales
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA, 02115, USA
| | - Jerrod A Poe
- Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15261, USA
| | - Lori Emert-Sedlak
- Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15261, USA
| | - Christopher R Morgan
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA, 02115, USA
- Genzyme Corporation, Framingham, MA, 01701-9322, USA
| | - Thomas E Smithgall
- Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15261, USA
| | - John R Engen
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA, 02115, USA.
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137
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Gomez AM, Ouellet M, Deshiere A, Breton Y, Tremblay MJ. HIV-1-Mediated BAFF Secretion in Macrophages Does Not Require Endosomal TLRs, Type-I IFN, and Nef, but Depends on the Cellular Phenotype Status. THE JOURNAL OF IMMUNOLOGY 2016; 196:3806-17. [PMID: 27022194 DOI: 10.4049/jimmunol.1501249] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Accepted: 02/23/2016] [Indexed: 11/19/2022]
Abstract
HIV-1 infection is characterized by persistent viral replication, chronic immune activation, and CD4(+) T cell depletion. Moreover, several immune dysfunctions are observed in cells that are not targeted by the virus, such as B cells. Some B cell abnormalities include hypergammaglobulinemia, nonspecific B cell activation, class switching, increased cell turnover, breakage of tolerance, and a loss of the capacity to generate and maintain memory. Several cytokines and growth factors that are increased in the serum of HIV-1-infected individuals have been suggested to directly or indirectly trigger B cell activation, and one of these is BAFF. In this study, we investigate the ability of fully competent (R5-tropic) HIV-1 to induce BAFF production by monocyte-derived macrophages (MDMs). We demonstrate here that HIV-1 drives BAFF production in MDMs in a type-I IFN- and TLR-independent manner. Moreover, we determine that HIV-1 Nef accessory protein is dispensable in BAFF upregulation as a nef-deleted HIV-1 strain is still able to increase BAFF at levels similar to the wild type strain. Finally, we show that the macrophage phenotype status affects HIV-1 replication and BAFF induction, as both were abrogated in MDMs displaying a M1 phenotype. This study provides new useful information about the increased levels of BAFF observed during HIV-1 infection and highlights the importance of macrophages as a source of BAFF, a phenomenon that might contribute to B cell dysfunctions at inflammatory tissue sites in infected individuals.
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Affiliation(s)
- Alejandro M Gomez
- Axe des Maladies Infectieuses et Immunitaires, Centre de Recherche du Centre Hospitalier Universitaire de Québec-Université Laval, Quebec City, Quebec G1V 4G2, Canada; and
| | - Michel Ouellet
- Axe des Maladies Infectieuses et Immunitaires, Centre de Recherche du Centre Hospitalier Universitaire de Québec-Université Laval, Quebec City, Quebec G1V 4G2, Canada; and
| | - Alexandre Deshiere
- Axe des Maladies Infectieuses et Immunitaires, Centre de Recherche du Centre Hospitalier Universitaire de Québec-Université Laval, Quebec City, Quebec G1V 4G2, Canada; and
| | - Yann Breton
- Axe des Maladies Infectieuses et Immunitaires, Centre de Recherche du Centre Hospitalier Universitaire de Québec-Université Laval, Quebec City, Quebec G1V 4G2, Canada; and
| | - Michel J Tremblay
- Axe des Maladies Infectieuses et Immunitaires, Centre de Recherche du Centre Hospitalier Universitaire de Québec-Université Laval, Quebec City, Quebec G1V 4G2, Canada; and Département de Microbiologie-Infectiologie et Immunologie, Faculté de Médecine, Université Laval, Quebec City, Quebec G1V 0A6, Canada
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138
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Remodeling of the Host Cell Plasma Membrane by HIV-1 Nef and Vpu: A Strategy to Ensure Viral Fitness and Persistence. Viruses 2016; 8:67. [PMID: 26950141 PMCID: PMC4810257 DOI: 10.3390/v8030067] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2016] [Revised: 02/09/2016] [Accepted: 02/16/2016] [Indexed: 02/07/2023] Open
Abstract
The plasma membrane protects the cell from its surroundings and regulates cellular communication, homing, and metabolism. Not surprisingly, the composition of this membrane is highly controlled through the vesicular trafficking of proteins to and from the cell surface. As intracellular pathogens, most viruses exploit the host plasma membrane to promote viral replication while avoiding immune detection. This is particularly true for the enveloped human immunodeficiency virus (HIV), which assembles and obtains its lipid shell directly at the plasma membrane. HIV-1 encodes two proteins, negative factor (Nef) and viral protein U (Vpu), which function primarily by altering the quantity and localization of cell surface molecules to increase virus fitness despite host antiviral immune responses. These proteins are expressed at different stages in the HIV-1 life cycle and employ a variety of mechanisms to target both unique and redundant surface proteins, including the viral receptor CD4, host restriction factors, immunoreceptors, homing molecules, tetraspanins and membrane transporters. In this review, we discuss recent progress in the study of the Nef and Vpu targeting of host membrane proteins with an emphasis on how remodeling of the cell membrane allows HIV-1 to avoid host antiviral immune responses leading to the establishment of systemic and persistent infection.
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139
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Serena M, Giorgetti A, Busato M, Gasparini F, Diani E, Romanelli MG, Zipeto D. Molecular characterization of HIV-1 Nef and ACOT8 interaction: insights from in silico structural predictions and in vitro functional assays. Sci Rep 2016; 6:22319. [PMID: 26927806 PMCID: PMC4772117 DOI: 10.1038/srep22319] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Accepted: 02/11/2016] [Indexed: 11/29/2022] Open
Abstract
HIV-1 Nef interacts with several cellular proteins, among which the human peroxisomal thioesterase 8 (ACOT8). This interaction may be involved in the endocytosis regulation of membrane proteins and might modulate lipid composition in membrane rafts. Nef regions involved in the interaction have been experimentally characterized, whereas structural details of the ACOT8 protein are unknown. The lack of structural information hampers the comprehension of the functional consequences of the complex formation during HIV-1 infection. We modelled, through in silico predictions, the ACOT8 structure and we observed a high charge complementarity between Nef and ACOT8 surfaces, which allowed the identification of the ACOT8 putative contact points involved in the interaction. The predictions were validated by in vitro assays through the development of ACOT8 deletion mutants. Coimmunoprecipitation and immunofluorescence analyses showed that ACOT8 Arg45-Phe55 and Arg86-Pro93 regions are involved in Nef association. In addition, K91S mutation abrogated the interaction with Nef, indicating that Lys91 plays a key role in the interaction. Finally, when associated with ACOT8, Nef may be preserved from degradation. These findings improve the comprehension of the association between HIV-1 Nef and ACOT8, helping elucidating the biological effect of their interaction.
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Affiliation(s)
- Michela Serena
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Strada le Grazie 8, 37134 Verona, Italy
| | - Alejandro Giorgetti
- Department of Biotechnology, University of Verona, Strada le Grazie 15, 37134 Verona, Italy
| | - Mirko Busato
- Department of Biotechnology, University of Verona, Strada le Grazie 15, 37134 Verona, Italy
| | - Francesca Gasparini
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Strada le Grazie 8, 37134 Verona, Italy.,Department of Biotechnology, University of Verona, Strada le Grazie 15, 37134 Verona, Italy
| | - Erica Diani
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Strada le Grazie 8, 37134 Verona, Italy
| | - Maria Grazia Romanelli
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Strada le Grazie 8, 37134 Verona, Italy
| | - Donato Zipeto
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Strada le Grazie 8, 37134 Verona, Italy
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140
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Shrivastava S, Trivedi J, Mitra D. Gene expression profiling reveals Nef induced deregulation of lipid metabolism in HIV-1 infected T cells. Biochem Biophys Res Commun 2016; 472:169-74. [PMID: 26915805 DOI: 10.1016/j.bbrc.2016.02.089] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2016] [Accepted: 02/22/2016] [Indexed: 01/11/2023]
Abstract
Human Immunodeficiency Virus-1 (HIV-1) encodes a 27 kDa Negative Factor or Nef protein, which is increasingly proving to be a misnomer. Nef seems to be crucial for AIDS progression as individuals infected with nef-deleted strain of HIV were reported to become Long Term Non Progressors (LTNP). These findings necessitate tracing of Nef's footprint on landscape of cellular transcriptome favoring HIV-1 pathogenesis. We have tried to explore effect of Nef on cellular gene expression profile in conjunction with rest of HIV-1 proteins. Our results show that 237 genes are differentially regulated due to the presence of Nef during infection, which belong to several broad categories like "signaling", "apoptosis", "transcription" and "lipid metabolism" in gene ontology analysis. Furthermore, our results show that Nef causes disruption of lipid content in HIV-1 infected T cells. Molecular inhibitors of lipid metabolism like Atorvastatin and Ranolazine were found to have profound effect on wild type virus as compared to nef-deleted HIV-1. Thus our results suggest that interference in lipid metabolism is a potential mechanism through which Nef contributes in enhancing HIV-1 pathogenesis.
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Affiliation(s)
| | - Jay Trivedi
- National Centre for Cell Science, Pune, 411007, India
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141
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Hashimoto M, Bhuyan F, Hiyoshi M, Noyori O, Nasser H, Miyazaki M, Saito T, Kondoh Y, Osada H, Kimura S, Hase K, Ohno H, Suzu S. Potential Role of the Formation of Tunneling Nanotubes in HIV-1 Spread in Macrophages. THE JOURNAL OF IMMUNOLOGY 2016; 196:1832-41. [PMID: 26773158 DOI: 10.4049/jimmunol.1500845] [Citation(s) in RCA: 88] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Accepted: 12/11/2015] [Indexed: 12/13/2022]
Abstract
Tunneling nanotubes (TNTs), the long membrane extensions connecting distant cells, have emerged as a novel form of cell-to-cell communication. However, it is not fully understood how and to what extent TNTs contribute to intercellular spread of pathogens including HIV-1. In this study, we show that HIV-1 promotes TNT formation per se via its protein Nef and a cellular protein M-Sec, which appears to mediate approximately half of viral spread among monocyte-derived macrophages (MDMs). A small compound that inhibits M-Sec-induced TNT formation reduced HIV-1 production by almost half in MDMs. Such inhibition was not observed with Nef-deficient mutant HIV-1 that fails to promote TNT formation and replicates less efficiently than the wild-type HIV-1 in MDMs. The TNT inhibitor-sensitive/Nef-promoting viral production was also observed in a T cell line ectopically expressing M-Sec, but not in another M-Sec(-) T cell line. Our results suggest the importance of TNTs in HIV-1 spread among MDMs and might answer the long-standing question how Nef promotes HIV-1 production in a cell type-specific manner.
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Affiliation(s)
- Michihiro Hashimoto
- Center for AIDS Research, International Research Center for Medical Sciences, Kumamoto University, Kumamoto, Kumamoto 860-0811, Japan
| | - Farzana Bhuyan
- Center for AIDS Research, International Research Center for Medical Sciences, Kumamoto University, Kumamoto, Kumamoto 860-0811, Japan
| | - Masateru Hiyoshi
- Center for AIDS Research, International Research Center for Medical Sciences, Kumamoto University, Kumamoto, Kumamoto 860-0811, Japan
| | - Osamu Noyori
- Center for AIDS Research, International Research Center for Medical Sciences, Kumamoto University, Kumamoto, Kumamoto 860-0811, Japan
| | - Hesham Nasser
- Center for AIDS Research, International Research Center for Medical Sciences, Kumamoto University, Kumamoto, Kumamoto 860-0811, Japan
| | - Mitsue Miyazaki
- Center for AIDS Research, International Research Center for Medical Sciences, Kumamoto University, Kumamoto, Kumamoto 860-0811, Japan
| | - Tamio Saito
- RIKEN Center for Sustainable Resource Science, Wako, Saitama 351-0198, Japan; and
| | - Yasumitsu Kondoh
- RIKEN Center for Sustainable Resource Science, Wako, Saitama 351-0198, Japan; and
| | - Hiroyuki Osada
- RIKEN Center for Sustainable Resource Science, Wako, Saitama 351-0198, Japan; and
| | - Shunsuke Kimura
- Laboratory for Intestinal Ecosystem, RIKEN Center for Integrative Medical Sciences, Yokohama, Kanagawa 230-0045, Japan
| | - Koji Hase
- Laboratory for Intestinal Ecosystem, RIKEN Center for Integrative Medical Sciences, Yokohama, Kanagawa 230-0045, Japan
| | - Hiroshi Ohno
- Laboratory for Intestinal Ecosystem, RIKEN Center for Integrative Medical Sciences, Yokohama, Kanagawa 230-0045, Japan
| | - Shinya Suzu
- Center for AIDS Research, International Research Center for Medical Sciences, Kumamoto University, Kumamoto, Kumamoto 860-0811, Japan;
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142
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Nef Proteins from HIV-1 Elite Controllers Are Inefficient at Preventing Antibody-Dependent Cellular Cytotoxicity. J Virol 2015; 90:2993-3002. [PMID: 26719277 DOI: 10.1128/jvi.02973-15] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Accepted: 12/22/2015] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Impairment of Nef function, including reduced CD4 downregulation, was described in a subset of HIV-1-infected individuals that control viral replication without antiretroviral treatment (elite controllers [EC]). Elimination of HIV-1-infected cells by antibody-dependent cellular cytotoxicity (ADCC) requires the presence of envelope glycoproteins (Env) in the CD4-bound conformation, raising the possibility that accumulating CD4 at the surface of virus-infected cells in EC could interact with Env and thereby sensitize these cells to ADCC. We observed a significant increase in the exposure of Env epitopes targeted by ADCC-mediating antibodies at the surface of cells expressing Nef isolates from EC; this correlated with enhanced susceptibility to ADCC. Altogether, our results suggest that enhanced susceptibility of HIV-1-infected cells to ADCC may contribute to the EC phenotype. IMPORTANCE Nef clones derived from elite controllers (EC) have been shown to be attenuated for CD4 downregulation; how this contributes to the nonprogressor phenotype of these infected individuals remains uncertain. Increasing evidence supports a role for HIV-specific antibody-dependent cellular cytotoxicity (ADCC) in controlling viral infection and replication. Here, we show that residual CD4 left at the surface of cells expressing Nef proteins isolated from ECs are sufficient to allow Env-CD4 interaction, leading to increased exposure of Env CD4-induced epitopes and increased susceptibility of infected cells to ADCC. Our results suggest that ADCC might be an active immune mechanism in EC that helps to maintain durable suppression of viral replication and low plasma viremia level in this rare subset of infected individuals. Therefore, targeting Nef's ability to downregulate CD4 could render HIV-1-infected cells susceptible to ADCC and thus have therapeutic utility.
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143
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Martínez-Bonet M, Palladino C, Briz V, Rudolph JM, Fackler OT, Relloso M, Muñoz-Fernandez MA, Madrid R. A Conserved GPG-Motif in the HIV-1 Nef Core Is Required for Principal Nef-Activities. PLoS One 2015; 10:e0145239. [PMID: 26700863 PMCID: PMC4689412 DOI: 10.1371/journal.pone.0145239] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2015] [Accepted: 11/30/2015] [Indexed: 12/26/2022] Open
Abstract
To find out new determinants required for Nef activity we performed a functional alanine scanning analysis along a discrete but highly conserved region at the core of HIV-1 Nef. We identified the GPG-motif, located at the 121–137 region of HIV-1 NL4.3 Nef, as a novel protein signature strictly required for the p56Lck dependent Nef-induced CD4-downregulation in T-cells. Since the Nef-GPG motif was dispensable for CD4-downregulation in HeLa-CD4 cells, Nef/AP-1 interaction and Nef-dependent effects on Tf-R trafficking, the observed effects on CD4 downregulation cannot be attributed to structure constraints or to alterations on general protein trafficking. Besides, we found that the GPG-motif was also required for Nef-dependent inhibition of ring actin re-organization upon TCR triggering and MHCI downregulation, suggesting that the GPG-motif could actively cooperate with the Nef PxxP motif for these HIV-1 Nef-related effects. Finally, we observed that the Nef-GPG motif was required for optimal infectivity of those viruses produced in T-cells. According to these findings, we propose the conserved GPG-motif in HIV-1 Nef as functional region required for HIV-1 infectivity and therefore with a potential interest for the interference of Nef activity during HIV-1 infection.
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Affiliation(s)
- Marta Martínez-Bonet
- Laboratorio de Inmunobiología Molecular, Instituto de Investigación Biomédica Gregorio Marañón (IISGM), 28007 Madrid, Spain
| | - Claudia Palladino
- Laboratorio de Inmunobiología Molecular, Instituto de Investigación Biomédica Gregorio Marañón (IISGM), 28007 Madrid, Spain
| | - Veronica Briz
- Laboratorio de Inmunobiología Molecular, Instituto de Investigación Biomédica Gregorio Marañón (IISGM), 28007 Madrid, Spain
| | - Jochen M. Rudolph
- Department of Infectious Diseases, Integrative Virology, University Hospital Heidelberg, Heidelberg, Germany
| | - Oliver T. Fackler
- Department of Infectious Diseases, Integrative Virology, University Hospital Heidelberg, Heidelberg, Germany
| | - Miguel Relloso
- Laboratorio de Inmunobiología Molecular, Instituto de Investigación Biomédica Gregorio Marañón (IISGM), 28007 Madrid, Spain
| | - Maria Angeles Muñoz-Fernandez
- Laboratorio de Inmunobiología Molecular, Instituto de Investigación Biomédica Gregorio Marañón (IISGM), 28007 Madrid, Spain
| | - Ricardo Madrid
- Departament of Virology. Centro de Biología Molecular Severo Ochoa, CSIC/UAM, Madrid, Spain
- * E-mail:
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144
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Gabriel B, Fiebig U, Hohn O, Plesker R, Coulibaly C, Cichutek K, Mühlebach MD, Bannert N, Kurth R, Norley S. Suppressing active replication of a live attenuated simian immunodeficiency virus vaccine does not abrogate protection from challenge. Virology 2015; 489:1-11. [PMID: 26685794 DOI: 10.1016/j.virol.2015.11.030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Revised: 10/14/2015] [Accepted: 11/28/2015] [Indexed: 10/22/2022]
Abstract
Although safety concerns preclude the use of live attenuated HIV vaccines in humans, they provide a useful system for identifying the elusive correlates of protective immunity in the SIV/macaque animal model. However, a number of pieces of evidence suggest that protection may result from prior occupancy of susceptible target cells by the vaccine virus rather than the immune response. To address this, we developed a Nef-deletion variant of an RT-SHIV whose active replication could be shut off by treatment with RT-inhibitors. Groups of macaques were inoculated with the ∆Nef-RT-SHIV and immune responses allowed to develop before antiretroviral treatment and subsequent challenge with wild-type SIVmac239. Vaccinated animals either resisted infection fully or significantly controlled the subsequent viremia. However, there was no difference between animals undergoing replication of the vaccine virus and those without. This strongly suggests that competition for available target cells does not play a role in protection.
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145
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Spotlight on HIV-1 Nef: SERINC3 and SERINC5 Identified as Restriction Factors Antagonized by the Pathogenesis Factor. Viruses 2015; 7:6730-8. [PMID: 26703715 PMCID: PMC4690893 DOI: 10.3390/v7122970] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Revised: 12/15/2015] [Accepted: 12/16/2015] [Indexed: 12/20/2022] Open
Abstract
The Nef protein is an accessory gene product encoded by human immunodeficiency virus types 1 and 2 (HIV-1/-2) and simian immunodeficiency virus (SIV) that boosts virus replication in the infected host and accelerates disease progression. Unlike the HIV-1 accessory proteins Vif, Vpr and Vpu, Nef was, until recently, not known to antagonize the antiviral activity of a host cell restriction factor. Two recent reports now describe the host cell proteins serine incorporator 3 and 5 (SERINC3 and SERINC5) as potent inhibitors of HIV-1 particle infectivity and demonstrate that Nef counteracts these effects. These findings establish SERINC3/5 as restrictions to HIV replication in human cells and define a novel activity for the HIV pathogenesis factor Nef.
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146
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Alberti MO, Jones JJ, Miglietta R, Ding H, Bakshi RK, Edmonds TG, Kappes JC, Ochsenbauer C. Optimized Replicating Renilla Luciferase Reporter HIV-1 Utilizing Novel Internal Ribosome Entry Site Elements for Native Nef Expression and Function. AIDS Res Hum Retroviruses 2015; 31:1278-96. [PMID: 26101895 DOI: 10.1089/aid.2015.0074] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
We previously developed replication-competent reporter HIV-1 (referred to herein as LucR.T2A reporter viruses), utilizing a "ribosome skipping" T2A peptide strategy to link Renilla luciferase (LucR) with Nef expression. The demonstrated utility for HIV-1 vaccine and transmission study applications included measurement of neutralizing antibody (NAb) activity in vaccine sera, improved cell-mediated virus inhibition assays, such as T cell-mediated virus inhibition and antibody-dependent cell-mediated cytotoxicity (ADCC) assays, and humanized mouse models. Herein, we extend our prior work and introduce reporter virus technology for applications that require fully functional Nef. We demonstrate that in CD4(+) T cells productively infected with LucR.T2A reporter viruses, T2A peptide-driven Nef expression and function, such as down-regulation of surface CD4 and MHC-I, were impaired. We overcame this limitation of LucR.T2A reporter viruses and achieved physiological Nef expression and function by engineering novel LucR reporter HIV-1 comprising 11 different internal ribosome entry site (IRES) elements chosen for size and relative activity. A range of Nef expression was observed in 293T cells transfected with the different LucR.IRES reporter virus constructs. Iteratively, we identified IRES reporter genomes that expressed Nef closest to physiological levels and produced virus with infectivity, titers, and replication kinetics similar to nonreporter viruses. Our results demonstrated that LucR reporter activity was stable over multiple replication cycles in peripheral blood mononuclear cells (PBMCs). Furthermore, we analyzed Nef functionality, i.e., down-modulation of MHC-I and CD4, following infection of T cell lines and PBMCs. Unlike LucR.T2A reporter virus, one of the redesigned LucR.IRES reporter viruses [containing the modified encephalomyocarditis virus (EMCV) 6ATR IRES element, "6ATRi"] demonstrated Nef expression and function similar to parental "nonreporter" virus. In a previously validated (nef-independent) T cell-based NAb neutralization assay, LucR.6ATRi reporter virus performed indistinguishably from LucR.T2A reporter virus. In summary, reporter viruses comprising the "6ATRi" element promise to augment HIV-1 vaccine and transmission research approaches requiring a sensitive reporter readout combined with wild-type Nef function.
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Affiliation(s)
- Michael O. Alberti
- Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama
| | - Jennifer J. Jones
- Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama
| | - Riccardo Miglietta
- Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama
| | - Haitao Ding
- Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama
| | - Rakesh K. Bakshi
- Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama
| | - Tara G. Edmonds
- Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama
| | - John C. Kappes
- Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama
- Center for AIDS Research, University of Alabama at Birmingham, Birmingham, Alabama
- Birmingham Veterans Affairs Medical Center, Research Service, Birmingham, Alabama
| | - Christina Ochsenbauer
- Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama
- Center for AIDS Research, University of Alabama at Birmingham, Birmingham, Alabama
- Birmingham Veterans Affairs Medical Center, Research Service, Birmingham, Alabama
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147
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van der Velden YU, Kleibeuker W, Harwig A, Klaver B, Siteur-van Rijnstra E, Frankin E, Berkhout B, Das AT. Construction of Nef-positive doxycycline-dependent HIV-1 variants using bicistronic expression elements. Virology 2015; 488:96-107. [PMID: 26615334 DOI: 10.1016/j.virol.2015.11.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Revised: 10/14/2015] [Accepted: 11/06/2015] [Indexed: 11/19/2022]
Abstract
Conditionally replicating HIV-1 variants that can be switched on and off at will are attractive tools for HIV research. We previously developed a genetically modified HIV-1 variant that replicates exclusively when doxycycline (dox) is administered. The nef gene in this HIV-rtTA variant was replaced with the gene encoding the dox-dependent rtTA transcriptional activator. Because loss of Nef expression compromises virus replication in primary cells and precludes studies on Nef function, we tested different approaches to restore Nef production in HIV-rtTA. Strategies that involved translation via an EMCV or synthetic internal ribosome entry site (IRES) failed because these elements were incompatible with efficient virus replication. Fusion protein approaches with the FMDV 2A peptide and human ubiquitin were successful and resulted in genetically-stable Nef-expressing HIV-rtTA strains that replicate more efficiently in primary T-cells and human immune system (HIS) mice than Nef-deficient variants, thus confirming the positive effect of Nef on in vivo virus replication.
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Affiliation(s)
- Yme U van der Velden
- Laboratory of Experimental Virology, Department of Medical Microbiology, Center for Infection and Immunity Amsterdam (CINIMA), Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Wendy Kleibeuker
- Laboratory of Experimental Virology, Department of Medical Microbiology, Center for Infection and Immunity Amsterdam (CINIMA), Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Alex Harwig
- Laboratory of Experimental Virology, Department of Medical Microbiology, Center for Infection and Immunity Amsterdam (CINIMA), Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Bep Klaver
- Laboratory of Experimental Virology, Department of Medical Microbiology, Center for Infection and Immunity Amsterdam (CINIMA), Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Esther Siteur-van Rijnstra
- Laboratory of Experimental Virology, Department of Medical Microbiology, Center for Infection and Immunity Amsterdam (CINIMA), Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Esmay Frankin
- Laboratory of Experimental Virology, Department of Medical Microbiology, Center for Infection and Immunity Amsterdam (CINIMA), Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Ben Berkhout
- Laboratory of Experimental Virology, Department of Medical Microbiology, Center for Infection and Immunity Amsterdam (CINIMA), Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Atze T Das
- Laboratory of Experimental Virology, Department of Medical Microbiology, Center for Infection and Immunity Amsterdam (CINIMA), Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
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148
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Nomura T, Yamamoto H, Ishii H, Akari H, Naruse TK, Kimura A, Matano T. Broadening of Virus-Specific CD8+ T-Cell Responses Is Indicative of Residual Viral Replication in Aviremic SIV Controllers. PLoS Pathog 2015; 11:e1005247. [PMID: 26536034 PMCID: PMC4633064 DOI: 10.1371/journal.ppat.1005247] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Accepted: 10/02/2015] [Indexed: 12/01/2022] Open
Abstract
Control of HIV replication is a rare immunological event, providing clues to understand the viral control mechanism. CD8+ T-cell responses are crucial for virus control, but it is unclear whether lasting HIV containment can be achieved after establishment of infection. Here, we describe lasting SIV containment in a macaque AIDS model. Analysis of ten rhesus macaques that controlled viremia for 2 years post-infection found accumulation of proviral gag and nef CD8+ T-cell escape mutations in four of them. These four controllers mounted CD8+ T cells targeting Gag, Nef, and other viral proteins at 4 months, suggesting that broadening of CD8+ T-cell targets can be an indicator of the beginning of viral control failure. The remaining six aviremic SIV controllers, however, harbored proviruses without mutations and showed no or little broadening of their CD8+ T-cell responses in the chronic phase. Indeed, three of the latter six exhibiting no change in CD8+ T-cell targets showed gradual decreases in SIV-specific CD8+ T-cell frequencies, implying a concomitant reduction in viral replication. Thus, stability of the breadth of virus-specific CD8+ T-cell responses may represent a status of lasting HIV containment by CD8+ T cells. CD8+ T-cell responses are crucial for HIV control, but it is unclear whether lasting HIV containment can be achieved after establishment of infection. Several T cell-based vaccine trials have currently shown primary viremia control in macaque AIDS models of simian immunodeficiency virus (SIV) infection, but residual viral replication may occur, followed by accumulation of viral CD8+ T-cell escape mutations, possibly leading to eventual viremia rebound. In the present study, we analyzed ten rhesus macaques that controlled SIV replication without detectable viremia for more than 2 years. Animals were divided into two groups on the basis of proviral genome sequences at 2 years post-infection. Analysis of the first group exhibiting multiple CD8+ T-cell escape mutations indicated that broadening of CD8+ T-cell responses can be an indicator of the beginning of viral control failure. Conversely, analysis of the second group having no mutation suggested that stability of the breadth of virus-specific CD8+ T-cell responses represents a status of lasting HIV containment by CD8+ T cells. Thus, this study presents a model of stable SIV containment, contributing to elucidation of the requisites for lasting HIV control.
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Affiliation(s)
- Takushi Nomura
- AIDS Research Center, National Institute of Infectious Diseases, Tokyo, Japan
| | - Hiroyuki Yamamoto
- AIDS Research Center, National Institute of Infectious Diseases, Tokyo, Japan
| | - Hiroshi Ishii
- AIDS Research Center, National Institute of Infectious Diseases, Tokyo, Japan
| | - Hirofumi Akari
- Center for Human Evolution Modeling Research, Primate Research Institute, Kyoto University, Inuyama, Aichi, Japan
| | - Taeko K. Naruse
- Department of Molecular Pathogenesis, Medical Research Institute, Tokyo Medical and Dental University, Tokyo, Japan
| | - Akinori Kimura
- Department of Molecular Pathogenesis, Medical Research Institute, Tokyo Medical and Dental University, Tokyo, Japan
| | - Tetsuro Matano
- AIDS Research Center, National Institute of Infectious Diseases, Tokyo, Japan
- The Institute of Medical Science, The University of Tokyo, Tokyo, Japan
- * E-mail:
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149
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Usami Y, Wu Y, Göttlinger HG. SERINC3 and SERINC5 restrict HIV-1 infectivity and are counteracted by Nef. Nature 2015; 526:218-23. [PMID: 26416733 PMCID: PMC4600458 DOI: 10.1038/nature15400] [Citation(s) in RCA: 330] [Impact Index Per Article: 36.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Accepted: 08/18/2015] [Indexed: 12/13/2022]
Abstract
HIV-1 Nef and the unrelated murine leukemia virus glycoGag strongly enhance the infectivity of HIV-1 virions produced in certain cell types in a clathrin-dependent manner. Here we show that Nef and glycoGag prevent the incorporation of the multipass transmembrane proteins SERINC3 and SERINC5 into HIV-1 virions to an extent that correlates with infectivity enhancement. Silencing of SERINC3 together with SERINC5 precisely phenocopied the effects of Nef and glycoGag on HIV-1 infectivities. The infectivity of nef-deficient virions increased more than 100-fold when produced in double-knockout human CD4+ T cells that lack both SERINC3 and SERINC5, and re-expression experiments confirmed that the absence of SERINC3 and SERINC5 accounted for the infectivity enhancement. Furthermore, SERINC3 and SERINC5 together restricted HIV-1 replication, and this restriction was evaded by Nef. SERINC3 and SERINC5 are highly expressed in primary human HIV-1 target cells, and inhibiting their downregulation by Nef is a potential strategy to combat HIV/AIDS.
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Affiliation(s)
- Yoshiko Usami
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA
| | - Yuanfei Wu
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA
| | - Heinrich G Göttlinger
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA
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150
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HIV-1 Nef promotes infection by excluding SERINC5 from virion incorporation. Nature 2015; 526:212-7. [PMID: 26416734 DOI: 10.1038/nature15399] [Citation(s) in RCA: 325] [Impact Index Per Article: 36.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Accepted: 08/18/2015] [Indexed: 12/18/2022]
Abstract
HIV-1 Nef, a protein important for the development of AIDS, has well-characterized effects on host membrane trafficking and receptor downregulation. By an unidentified mechanism, Nef increases the intrinsic infectivity of HIV-1 virions in a host-cell-dependent manner. Here we identify the host transmembrane protein SERINC5, and to a lesser extent SERINC3, as a potent inhibitor of HIV-1 particle infectivity that is counteracted by Nef. SERINC5 localizes to the plasma membrane, where it is efficiently incorporated into budding HIV-1 virions and impairs subsequent virion penetration of susceptible target cells. Nef redirects SERINC5 to a Rab7-positive endosomal compartment and thereby excludes it from HIV-1 particles. The ability to counteract SERINC5 was conserved in Nef encoded by diverse primate immunodeficiency viruses, as well as in the structurally unrelated glycosylated Gag from murine leukaemia virus. These examples of functional conservation and convergent evolution emphasize the fundamental importance of SERINC5 as a potent anti-retroviral factor.
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