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Curlin JZ, Schmitt K, Remling-Mulder L, Moriarty R, Baczenas JJ, Goff K, O’Connor S, Stenglein M, Marx PA, Akkina R. In vivo infection dynamics and human adaptive changes of SIVsm-derived viral siblings SIVmac239, SIV B670 and SIVhu in humanized mice as a paralog of HIV-2 genesis. FRONTIERS IN VIROLOGY (LAUSANNE, SWITZERLAND) 2021; 1:813606. [PMID: 37168442 PMCID: PMC10168645 DOI: 10.3389/fviro.2021.813606] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Simian immunodeficiency virus native to sooty mangabeys (SIVsm) is believed to have given rise to HIV-2 through cross-species transmission and evolution in the human. SIVmac239 and SIVB670, pathogenic to macaques, and SIVhu, isolated from an accidental human infection, also have origins in SIVsm. With their common ancestral lineage as that of HIV-2 from the progenitor SIVsm, but with different passage history in different hosts, they provide a unique opportunity to evaluate cross-species transmission to a new host and their adaptation/evolution both in terms of potential genetic and phenotypic changes. Using humanized mice with a transplanted human system, we evaluated in vivo replication kinetics, CD4+ T cell dynamics and genetic adaptive changes during serial passage with a goal to understand their evolution under human selective immune pressure. All the three viruses readily infected hu-mice causing chronic viremia. While SIVmac and SIVB670 caused CD4+ T cell depletion during sequential passaging, SIVhu with a deletion in nef gene was found to be less pathogenic. Deep sequencing of the genomes of these viruses isolated at different times revealed numerous adaptive mutations of significance that increased in frequency during sequential passages. The ability of these viruses to infect and replicate in humanized mice provides a new small animal model to study SIVs in vivo in addition to more expensive macaques. Since SIVmac and related viruses have been indispensable in many areas of HIV pathogenesis, therapeutics and cure research, availability of this small animal hu-mouse model that is susceptible to both SIV and HIV viruses is likely to open novel avenues of investigation for comparative studies using the same host.
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Affiliation(s)
- James Z. Curlin
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, USA
- Antiviral Discovery, Evaluation and Application Research (ADEAR) Training Program, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Kimberly Schmitt
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, USA
| | - Leila Remling-Mulder
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, USA
| | - Ryan Moriarty
- Department of Pathology and Laboratory Medicine, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
| | - John J. Baczenas
- Department of Pathology and Laboratory Medicine, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
| | - Kelly Goff
- Department of Tropical Medicine, Tulane University School of Public Health and Tropical Medicine, New Orleans, LA, USA
| | - Shelby O’Connor
- Department of Pathology and Laboratory Medicine, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
| | - Mark Stenglein
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, USA
| | - Preston A. Marx
- Department of Tropical Medicine, Tulane University School of Public Health and Tropical Medicine, New Orleans, LA, USA
- Tulane National Primate Research Center, Covington, LA, USA
| | - Ramesh Akkina
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, USA
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Zhao Z, Fagerlund R, Tossavainen H, Hopfensperger K, Lotke R, Srinivasachar Badarinarayan S, Kirchhoff F, Permi P, Sato K, Sauter D, Saksela K. Evolutionary plasticity of SH3 domain binding by Nef proteins of the HIV-1/SIVcpz lentiviral lineage. PLoS Pathog 2021; 17:e1009728. [PMID: 34780577 PMCID: PMC8629392 DOI: 10.1371/journal.ppat.1009728] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Revised: 11/29/2021] [Accepted: 10/28/2021] [Indexed: 11/18/2022] Open
Abstract
The accessory protein Nef of human and simian immunodeficiency viruses (HIV and SIV) is an important pathogenicity factor known to interact with cellular protein kinases and other signaling proteins. A canonical SH3 domain binding motif in Nef is required for most of these interactions. For example, HIV-1 Nef activates the tyrosine kinase Hck by tightly binding to its SH3 domain. An archetypal contact between a negatively charged SH3 residue and a highly conserved arginine in Nef (Arg77) plays a key role here. Combining structural analyses with functional assays, we here show that Nef proteins have also developed a distinct structural strategy—termed the "R-clamp”—that favors the formation of this salt bridge via buttressing Arg77. Comparison of evolutionarily diverse Nef proteins revealed that several distinct R-clamps have evolved that are functionally equivalent but differ in the side chain compositions of Nef residues 83 and 120. Whereas a similar R-clamp design is shared by Nef proteins of HIV-1 groups M, O, and P, as well as SIVgor, the Nef proteins of SIV from the Eastern chimpanzee subspecies (SIVcpzP.t.s.) exclusively utilize another type of R-clamp. By contrast, SIV of Central chimpanzees (SIVcpzP.t.t.) and HIV-1 group N strains show more heterogenous R-clamp design principles, including a non-functional evolutionary intermediate of the aforementioned two classes. These data add to our understanding of the structural basis of SH3 binding and kinase deregulation by Nef, and provide an interesting example of primate lentiviral protein evolution. Viral replication depends on interactions with a plethora of host cell proteins. Cellular protein interactions are typically mediated by specialized binding modules, such as the SH3 domain. To gain access to host cell regulation viruses have evolved to contain SH3 domain binding sites in their proteins, a notable example of which is the HIV-1 Nef protein. Here we show that during the primate lentivirus evolution the structural strategy that underlies the avid binding of Nef to cellular SH3 domains, which we have dubbed the R-clamp, has been generated via alternative but functionally interchangeable molecular designs. These patterns of SH3 recognition depend on the amino acid combinations at the positions corresponding to residues 83 and 120 in the consensus HIV-1 Nef sequence, and are distinctly different in Nef proteins from SIVs of Eastern and Central chimpanzees, gorillas, and the four groups of HIV-1 that have independently originated from the latter two. These results highlight the evolutionary plasticity of viral proteins, and have implications on therapeutic development aiming to interfere with SH3 binding of Nef.
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Affiliation(s)
- Zhe Zhao
- Department of Virology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Riku Fagerlund
- Department of Virology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Helena Tossavainen
- Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland
| | - Kristina Hopfensperger
- Institute for Medical Virology and Epidemiology of Viral Diseases, University Hospital Tübingen, Tübingen, Germany
| | - Rishikesh Lotke
- Institute for Medical Virology and Epidemiology of Viral Diseases, University Hospital Tübingen, Tübingen, Germany
| | | | - Frank Kirchhoff
- Institute of Molecular Virology, Ulm University Medical Center, Ulm, Germany
| | - Perttu Permi
- Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland
- Department of Chemistry, Nanoscience Center, University of Jyväskylä, Jyväskylä, Finland
| | - Kei Sato
- Division of Systems Virology, Department of Infectious Disease Control, International Research Center for Infectious Diseases, Institute of Medical Science, The University of Tokyo, Tokyo, Japan
| | - Daniel Sauter
- Institute for Medical Virology and Epidemiology of Viral Diseases, University Hospital Tübingen, Tübingen, Germany
- Institute of Molecular Virology, Ulm University Medical Center, Ulm, Germany
| | - Kalle Saksela
- Department of Virology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
- * E-mail:
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Castro-Gonzalez S, Chen Y, Benjamin J, Shi Y, Serra-Moreno R. Residues T 48 and A 49 in HIV-1 NL4-3 Nef are responsible for the counteraction of autophagy initiation, which prevents the ubiquitin-dependent degradation of Gag through autophagosomes. Retrovirology 2021; 18:33. [PMID: 34711257 PMCID: PMC8555152 DOI: 10.1186/s12977-021-00576-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Accepted: 10/05/2021] [Indexed: 11/21/2022] Open
Abstract
BACKGROUND Autophagy plays an important role as a cellular defense mechanism against intracellular pathogens, like viruses. Specifically, autophagy orchestrates the recruitment of specialized cargo, including viral components needed for replication, for lysosomal degradation. In addition to this primary role, the cleavage of viral structures facilitates their association with pattern recognition receptors and MHC-I/II complexes, which assists in the modulation of innate and adaptive immune responses against these pathogens. Importantly, whereas autophagy restricts the replicative capacity of human immunodeficiency virus type 1 (HIV-1), this virus has evolved the gene nef to circumvent this process through the inhibition of early and late stages of the autophagy cascade. Despite recent advances, many details of the mutual antagonism between HIV-1 and autophagy still remain unknown. Here, we uncover the genetic determinants that drive the autophagy-mediated restriction of HIV-1 as well as the counteraction imposed by Nef. Additionally, we also examine the implications of autophagy antagonism in HIV-1 infectivity. RESULTS We found that sustained activation of autophagy potently inhibits HIV-1 replication through the degradation of HIV-1 Gag, and that this effect is more prominent for nef-deficient viruses. Gag re-localizes to autophagosomes where it interacts with the autophagosome markers LC3 and SQSTM1. Importantly, autophagy-mediated recognition and recruitment of Gag requires the myristoylation and ubiquitination of this virus protein, two post-translational modifications that are essential for Gag's central role in virion assembly and budding. We also identified residues T48 and A49 in HIV-1 NL4-3 Nef as responsible for impairing the early stages of autophagy. Finally, a survey of pandemic HIV-1 transmitted/founder viruses revealed that these isolates are highly resistant to autophagy restriction. CONCLUSIONS This study provides evidence that autophagy antagonism is important for virus replication and suggests that the ability of Nef to counteract autophagy may have played an important role in mucosal transmission. Hence, disabling Nef in combination with the pharmacological manipulation of autophagy represents a promising strategy to prevent HIV spread.
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Affiliation(s)
| | - Yuexuan Chen
- Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY, USA
| | - Jared Benjamin
- Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY, USA
| | - Yuhang Shi
- Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY, USA
| | - Ruth Serra-Moreno
- Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY, USA.
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Khan N, Geiger JD. Role of Viral Protein U (Vpu) in HIV-1 Infection and Pathogenesis. Viruses 2021; 13:1466. [PMID: 34452331 PMCID: PMC8402909 DOI: 10.3390/v13081466] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 07/16/2021] [Accepted: 07/24/2021] [Indexed: 12/11/2022] Open
Abstract
Human immunodeficiency virus (HIV)-1 and HIV-2 originated from cross-species transmission of simian immunodeficiency viruses (SIVs). Most of these transfers resulted in limited spread of these viruses to humans. However, one transmission event involving SIVcpz from chimpanzees gave rise to group M HIV-1, with M being the principal strain of HIV-1 responsible for the AIDS pandemic. Vpu is an HIV-1 accessory protein generated from Env/Vpu encoded bicistronic mRNA and localized in cytosolic and membrane regions of cells capable of being infected by HIV-1 and that regulate HIV-1 infection and transmission by downregulating BST-2, CD4 proteins levels, and immune evasion. This review will focus of critical aspects of Vpu including its zoonosis, the adaptive hurdles to cross-species transmission, and future perspectives and broad implications of Vpu in HIV-1 infection and dissemination.
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Affiliation(s)
| | - Jonathan D. Geiger
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, 504 Hamline Street, Room 110, Grand Forks, ND 58203, USA;
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5
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Hopfensperger K, Richard J, Stürzel CM, Bibollet-Ruche F, Apps R, Leoz M, Plantier JC, Hahn BH, Finzi A, Kirchhoff F, Sauter D. Convergent Evolution of HLA-C Downmodulation in HIV-1 and HIV-2. mBio 2020; 11:e00782-20. [PMID: 32665270 PMCID: PMC7360927 DOI: 10.1128/mbio.00782-20] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Accepted: 06/11/2020] [Indexed: 12/13/2022] Open
Abstract
HLA-C-mediated antigen presentation induces the killing of human immunodeficiency virus (HIV)-infected CD4+ T cells by cytotoxic T lymphocytes (CTLs). To evade killing, many HIV-1 group M strains decrease HLA-C surface levels using their accessory protein Vpu. However, some HIV-1 group M isolates lack this activity, possibly to prevent the activation of natural killer (NK) cells. Analyzing diverse primate lentiviruses, we found that Vpu-mediated HLA-C downregulation is not limited to pandemic group M but is also found in HIV-1 groups O and P as well as several simian immunodeficiency viruses (SIVs). We show that Vpu targets HLA-C primarily at the protein level, independently of its ability to suppress NF-κB-driven gene expression, and that in some viral lineages, HLA-C downregulation may come at the cost of efficient counteraction of the restriction factor tetherin. Remarkably, HIV-2, which does not carry a vpu gene, uses its accessory protein Vif to decrease HLA-C surface expression. This Vif activity requires intact binding sites for the Cullin5/Elongin ubiquitin ligase complex but is separable from its ability to counteract APOBEC3G. Similar to HIV-1 Vpu, the degree of HIV-2 Vif-mediated HLA-C downregulation varies considerably among different virus isolates. In agreement with opposing selection pressures in vivo, we show that the reduction of HLA-C surface levels by HIV-2 Vif is accompanied by increased NK cell-mediated killing. In summary, our results highlight the complex role of HLA-C in lentiviral infections and demonstrate that HIV-1 and HIV-2 have evolved at least two independent mechanisms to decrease HLA-C levels on infected cells.IMPORTANCE Genome-wide association studies suggest that HLA-C expression is a major determinant of viral load set points and CD4+ T cell counts in HIV-infected individuals. On the one hand, efficient HLA-C expression enables the killing of infected cells by cytotoxic T lymphocytes (CTLs). On the other hand, HLA-C sends inhibitory signals to natural killer (NK) cells and enhances the infectivity of newly produced HIV particles. HIV-1 group M viruses modulate HLA-C expression using the accessory protein Vpu, possibly to balance CTL- and NK cell-mediated immune responses. Here, we show that the second human immunodeficiency virus, HIV-2, can use its accessory protein Vif to evade HLA-C-mediated restriction. Furthermore, our mutational analyses provide insights into the underlying molecular mechanisms. In summary, our results reveal how the two human AIDS viruses modulate HLA-C, a key component of the antiviral immune response.
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Affiliation(s)
| | - Jonathan Richard
- Centre de Recherche du CHUM, Montreal, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, Canada
| | - Christina M Stürzel
- Institute of Molecular Virology, Ulm University Medical Center, Ulm, Germany
| | - Frederic Bibollet-Ruche
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Richard Apps
- NIH Center for Human Immunology, National Institutes of Health, Bethesda, Maryland, USA
| | - Marie Leoz
- Normandie Université, UNIROUEN, UNICAEN, GRAM 2.0, Rouen, France
| | - Jean-Christophe Plantier
- Normandie Université, UNIROUEN, UNICAEN, GRAM 2.0, Rouen University Hospital, Department of Virology, Laboratory Associated with the National Reference Center on HIV, Rouen, France
| | - Beatrice H Hahn
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Andrés Finzi
- Centre de Recherche du CHUM, Montreal, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, Canada
- Department of Microbiology and Immunology, McGill University, Montreal, Canada
| | - Frank Kirchhoff
- Institute of Molecular Virology, Ulm University Medical Center, Ulm, Germany
| | - Daniel Sauter
- Institute of Molecular Virology, Ulm University Medical Center, Ulm, Germany
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6
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Edoul G, Chia JE, Vidal N, Guichet E, Montavon C, Delaporte E, Mpoudi Ngole E, Ayouba A, Peeters M. High HIV burden and recent transmission chains in rural forest areas in southern Cameroon, where ancestors of HIV-1 have been identified in ape populations. INFECTION GENETICS AND EVOLUTION 2020; 84:104358. [PMID: 32439500 DOI: 10.1016/j.meegid.2020.104358] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 05/06/2020] [Accepted: 05/08/2020] [Indexed: 11/18/2022]
Abstract
We studied HIV prevalence and genetic diversity in rural forest areas in Cameroon, where chimpanzee and gorilla populations infected with the ancestors of the different HIV-1 groups have been identified and transmitted to humans during the 20th century. A total of 2812 individuals were studied, 924 from south-central, 1116 from south-east and 772 from south-west Cameroon. Of 208 (7.4%) samples that were confirmed for HIV-1 infection all belong to HIV-1 group M. In all sites and in all age categories, HIV-1 prevalence was higher in women (160/1599 (10.0%)) as compared to men (48/1213 (4.0%)) with the highest prevalence in women aged between 25 and 34 years (>17%). For 188/208 (92.3%) HIV-1 positive individuals, a fragment of the pol gene was successfully amplified and sequenced. Phylogenetic analysis showed predominance of CRF02_AG (58%), a large diversity of subtypes (A, D, F2 and G), nine different CRFs and more than 12% URFs. Interestingly, 35/188 (18.6%) HIV-1 strains form 12 recent transmission chains. The majority of the clusters are composed of two (n = 8) or three (n = 3) sequences but one cluster included ten HIV-1 strains from women living in four different villages on a major road for logging concessions in the south-east (60 km distance). In the three regions of Cameroon where the ancestors of the four HIV-1 groups have been transmitted to humans, we observed a high HIV prevalence, especially in the southeast where HIV-1 M originated. Many factors allowing rapid establishment in the human population and subsequent rapid spread to urban areas of a new retrovirus or other pathogens of zoonotic origin are now present. Our study shows clearly that some rural areas should also be considered as hot-spots for HIV infection. Prevention efforts together with growing access to HIV diagnosis and antiretroviral treatment are urgently needed in these remote areas.
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Affiliation(s)
- Ginette Edoul
- Centre de Recherche sur les Maladies Emergentes et Reemergentes (CREMER), Virology Laboratory IMPM-IRD, IMPM, Yaoundé, Cameroon
| | - Julius Ebua Chia
- Centre de Recherche sur les Maladies Emergentes et Reemergentes (CREMER), Virology Laboratory IMPM-IRD, IMPM, Yaoundé, Cameroon
| | - Nicole Vidal
- TransVIHMI, Institut de Recherche pour le Développement (IRD), INSERM, Université de Montpellier, Montpellier, France
| | - Emilande Guichet
- Centre de Recherche sur les Maladies Emergentes et Reemergentes (CREMER), Virology Laboratory IMPM-IRD, IMPM, Yaoundé, Cameroon
| | - Celine Montavon
- TransVIHMI, Institut de Recherche pour le Développement (IRD), INSERM, Université de Montpellier, Montpellier, France
| | - Eric Delaporte
- TransVIHMI, Institut de Recherche pour le Développement (IRD), INSERM, Université de Montpellier, Montpellier, France
| | - Eitel Mpoudi Ngole
- Centre de Recherche sur les Maladies Emergentes et Reemergentes (CREMER), Virology Laboratory IMPM-IRD, IMPM, Yaoundé, Cameroon
| | - Ahidjo Ayouba
- TransVIHMI, Institut de Recherche pour le Développement (IRD), INSERM, Université de Montpellier, Montpellier, France
| | - Martine Peeters
- TransVIHMI, Institut de Recherche pour le Développement (IRD), INSERM, Université de Montpellier, Montpellier, France.
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Evans JP, Liu SL. Multifaceted Roles of TIM-Family Proteins in Virus-Host Interactions. Trends Microbiol 2019; 28:224-235. [PMID: 31732320 DOI: 10.1016/j.tim.2019.10.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Revised: 09/25/2019] [Accepted: 10/10/2019] [Indexed: 01/16/2023]
Abstract
To enhance infection, enveloped viruses exploit adhesion molecules expressed on the surface of host cells. Specifically, phosphatidylserine (PS) receptors - including members of the human T cell immunoglobulin and mucin domain (TIM)-family - have gained attention for their ability to mediate the entry of many enveloped viruses. However, recent evidence that TIM-1 can restrict viral release reveals a new role for these PS receptors. Additionally, viral factors such as the HIV-1 accessory protein Nef can antagonize this antiviral activity of TIM-1 while host restriction factors such as SERINC5 can enhance it. In this review, we examine the various roles of PS receptors, specifically TIM-family proteins, and the intricate relationship between host and viral factors. Elucidating the multifunctional roles of PS receptors in virus-host interaction is important for understanding viral pathogenesis and developing novel antiviral therapeutics.
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Affiliation(s)
- John P Evans
- Molecular, Cellular and Developmental Biology Program, The Ohio State University, Columbus, OH 43210, USA; Center for Retrovirus Research, The Ohio State University, Columbus, OH 43210, USA; Department of Veterinary Biosciences, The Ohio State University, Columbus, OH 43210, USA
| | - Shan-Lu Liu
- Center for Retrovirus Research, The Ohio State University, Columbus, OH 43210, USA; Department of Veterinary Biosciences, The Ohio State University, Columbus, OH 43210, USA; Department of Microbial Infection and Immunity, The Ohio State University, Columbus, OH 43210, USA; Viruses and Emerging Pathogens Program, Infectious Diseases Institute, The Ohio State University, Columbus, OH 43210, USA.
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8
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Zotova AA, Atemasova AA, Filatov AV, Mazurov DV. HIV Restriction Factors and Their Ambiguous Role during Infection. Mol Biol 2019. [DOI: 10.1134/s0026893319020171] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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9
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Morris KL, Buffalo CZ, Stürzel CM, Heusinger E, Kirchhoff F, Ren X, Hurley JH. HIV-1 Nefs Are Cargo-Sensitive AP-1 Trimerization Switches in Tetherin Downregulation. Cell 2019; 174:659-671.e14. [PMID: 30053425 DOI: 10.1016/j.cell.2018.07.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Revised: 04/27/2018] [Accepted: 07/03/2018] [Indexed: 01/08/2023]
Abstract
The HIV accessory protein Nef counteracts immune defenses by subverting coated vesicle pathways. The 3.7 Å cryo-EM structure of a closed trimer of the clathrin adaptor AP-1, the small GTPase Arf1, HIV-1 Nef, and the cytosolic tail of the restriction factor tetherin suggested a mechanism for inactivating tetherin by Golgi retention. The 4.3 Å structure of a mutant Nef-induced dimer of AP-1 showed how the closed trimer is regulated by the dileucine loop of Nef. HDX-MS and mutational analysis were used to show how cargo dynamics leads to alternative Arf1 trimerization, directing Nef targets to be either retained at the trans-Golgi or sorted to lysosomes. Phosphorylation of the NL4-3 M-Nef was shown to regulate AP-1 trimerization, explaining how O-Nefs lacking this phosphosite counteract tetherin but most M-Nefs do not. These observations show how the higher-order organization of a vesicular coat can be allosterically modulated to direct cargoes to distinct fates.
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Affiliation(s)
- Kyle L Morris
- Department of Molecular and Cell Biology and California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Cosmo Z Buffalo
- Department of Molecular and Cell Biology and California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Christina M Stürzel
- Institute of Molecular Virology, Ulm University Medical Center, 89081 Ulm, Germany
| | - Elena Heusinger
- Institute of Molecular Virology, Ulm University Medical Center, 89081 Ulm, Germany
| | - Frank Kirchhoff
- Institute of Molecular Virology, Ulm University Medical Center, 89081 Ulm, Germany
| | - Xuefeng Ren
- Department of Molecular and Cell Biology and California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, CA 94720, USA.
| | - James H Hurley
- Department of Molecular and Cell Biology and California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, CA 94720, USA; Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
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10
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Abstract
HIV, the causative agent of AIDS, has a complex evolutionary history involving several cross-species transmissions and recombination events as well as changes in the repertoire and function of its accessory genes. Understanding these events and the adaptations to new host species provides key insights into innate defense mechanisms, viral dependencies on cellular factors, and prerequisites for the emergence of the AIDS pandemic. In addition, understanding the factors and adaptations required for the spread of HIV in the human population helps to better assess the risk of future lentiviral zoonoses and provides clues to how improved control of viral replication can be achieved. Here, we summarize our current knowledge on viral features and adaptations preceding the AIDS pandemic. We aim at providing a viral point of view, focusing on known key hurdles of each cross-species transmission and the mechanisms that HIV and its simian precursors evolved to overcome them.
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Affiliation(s)
- Daniel Sauter
- Institute of Molecular Virology, Ulm University Medical Centre, Ulm 89081, Germany
| | - Frank Kirchhoff
- Institute of Molecular Virology, Ulm University Medical Centre, Ulm 89081, Germany.
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11
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TIM-mediated inhibition of HIV-1 release is antagonized by Nef but potentiated by SERINC proteins. Proc Natl Acad Sci U S A 2019; 116:5705-5714. [PMID: 30842281 DOI: 10.1073/pnas.1819475116] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The T cell Ig and mucin domain (TIM) proteins inhibit release of HIV-1 and other enveloped viruses by interacting with cell- and virion-associated phosphatidylserine (PS). Here, we show that the Nef proteins of HIV-1 and other lentiviruses antagonize TIM-mediated restriction. TIM-1 more potently inhibits the release of Nef-deficient relative to Nef-expressing HIV-1, and ectopic expression of Nef relieves restriction. HIV-1 Nef does not down-regulate the overall level of TIM-1 expression, but promotes its internalization from the plasma membrane and sequesters its expression in intracellular compartments. Notably, Nef mutants defective in modulating membrane protein endocytic trafficking are incapable of antagonizing TIM-mediated inhibition of HIV-1 release. Intriguingly, depletion of SERINC3 or SERINC5 proteins in human peripheral blood mononuclear cells (PBMCs) attenuates TIM-1 restriction of HIV-1 release, in particular that of Nef-deficient viruses. In contrast, coexpression of SERINC3 or SERINC5 increases the expression of TIM-1 on the plasma membrane and potentiates TIM-mediated inhibition of HIV-1 production. Pulse-chase metabolic labeling reveals that the half-life of TIM-1 is extended by SERINC5 from <2 to ∼6 hours, suggesting that SERINC5 stabilizes the expression of TIM-1. Consistent with a role for SERINC protein in potentiating TIM-1 restriction, we find that MLV glycoGag and EIAV S2 proteins, which, like Nef, antagonize SERINC-mediated diminishment of HIV-1 infectivity, also effectively counteract TIM-mediated inhibition of HIV-1 release. Collectively, our work reveals a role of Nef in antagonizing TIM-1 and highlights the complex interplay between Nef and HIV-1 restriction by TIMs and SERINCs.
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12
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Abstract
Pandemic HIV-1, a human lentivirus, is the result of zoonotic transmission of SIV from chimpanzees (SIVcpz). How SIVcpz established spread in humans after spillover is an outstanding question. Lentiviral cross-species transmissions are exceptionally rare events. Nevertheless, the chimpanzee and the gorilla were part of the transmission chains that resulted in sustained infections that evolved into HIV-1. Although many restriction factors can repress the early stages of lentiviral replication, others target replication during the late phases. In some cases, viruses incorporate host proteins that interfere with subsequent rounds of replication. Though limited and small, HIVs and SIVs, including SIVcpz can use their genome products to modulate and escape some of these barriers and thus establish a chronic infection.
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Affiliation(s)
- Augustin Penda Twizerimana
- Clinic for Gastroenterology, Hepatology & Infectiology, Medical Faculty, Heinrich-Heine-University, Moorenstr. 5, 40225 Düsseldorf, Germany
| | - Rachel Scheck
- Clinic for Gastroenterology, Hepatology & Infectiology, Medical Faculty, Heinrich-Heine-University, Moorenstr. 5, 40225 Düsseldorf, Germany
| | - Dieter Häussinger
- Clinic for Gastroenterology, Hepatology & Infectiology, Medical Faculty, Heinrich-Heine-University, Moorenstr. 5, 40225 Düsseldorf, Germany
| | - Carsten Münk
- Clinic for Gastroenterology, Hepatology & Infectiology, Medical Faculty, Heinrich-Heine-University, Moorenstr. 5, 40225 Düsseldorf, Germany
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13
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Preadaptation of Simian Immunodeficiency Virus SIVsmm Facilitated Env-Mediated Counteraction of Human Tetherin by Human Immunodeficiency Virus Type 2. J Virol 2018; 92:JVI.00276-18. [PMID: 29976668 DOI: 10.1128/jvi.00276-18] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Accepted: 06/23/2018] [Indexed: 12/14/2022] Open
Abstract
The host restriction factor tetherin inhibits virion release from infected cells and poses a significant barrier to successful zoonotic transmission of primate lentiviruses to humans. While most simian immunodeficiency viruses (SIV), including the direct precursors of human immunodeficiency virus type 1 (HIV-1) and HIV-2, use their Nef protein to counteract tetherin in their natural hosts, they fail to antagonize the human tetherin ortholog. Pandemic HIV-1 group M and epidemic group O strains overcame this hurdle by adapting their Vpu and Nef proteins, respectively, whereas HIV-2 group A uses its envelope (Env) glycoprotein to counteract human tetherin. Whether or how the remaining eight groups of HIV-2 antagonize this antiviral factor has remained unclear. Here, we show that Nef proteins from diverse groups of HIV-2 do not or only modestly antagonize human tetherin, while their ability to downmodulate CD3 and CD4 is highly conserved. Experiments in transfected cell lines and infected primary cells revealed that not only Env proteins of epidemic HIV-2 group A but also those of a circulating recombinant form (CRF01_AB) and rare groups F and I decrease surface expression of human tetherin and significantly enhance progeny virus release. Intriguingly, we found that many SIVsmm Envs also counteract human as well as smm tetherin. Thus, Env-mediated tetherin antagonism in different groups of HIV-2 presumably stems from a preadaptation of their SIVsmm precursors to humans. In summary, we identified a phenotypic trait of SIVsmm that may have facilitated its successful zoonotic transmission to humans and the emergence of HIV-2.IMPORTANCE HIV-2 groups A to I resulted from nine independent cross-species transmission events of SIVsmm to humans and differ considerably in their prevalence and geographic spread. Thus, detailed characterization of these viruses offers a valuable means to elucidate immune evasion mechanisms and human-specific adaptations determining viral spread. In a systematic comparison of rare and epidemic HIV-2 groups and their simian SIVsmm counterparts, we found that the ability of Nef to downmodulate the primary viral entry receptor CD4 and the T cell receptor CD3 is conserved, while effects on CD28, CD74, and major histocompatibility complex class I surface expression vary considerably. Furthermore, we show that not only the Env proteins of HIV-2 groups A, AB, F, and I but also those of some SIVsmm isolates antagonize human tetherin. This finding helps to explain why SIVsmm has been able to cross the species barrier to humans on at least nine independent occasions.
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14
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HIV-1 group P infection: towards a dead-end infection? AIDS 2018; 32:1317-1322. [PMID: 29547436 DOI: 10.1097/qad.0000000000001791] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES HIV/1 group P (HIV-1/P) is the last HIV/1 group discovered and, to date, constitutes only two strains. To obtain new insight into this divergent group, we screened for new infections by developing specific tools, and analysed phenotypic and genotypic properties of the prototypic strain RBF168. In addition, the follow-up of the unique infected patient monitored so far has raised the knowledge of the natural history of this infection and its therapeutic management. DESIGN/METHODS We developed an HIV-1/P specific seromolecular strategy and screened over 29 498 specimen samples. Infectivity and evolution of the gag-30 position, considered as marker of adaptation to human, were explored by successive passages of RBF168 strain onto human peripheral blood mononuclear cells. Natural history and immunovirological responses to combined antiretroviral therapy (cART) were analysed based on CD4+ cells and plasmatic viral load evolution. RESULTS No new infection was detected. Infectivity of RBF168 was found lower, relative to other main HIV groups and the conservative methionine found in the gag-30 position revealed a lack of adaptation to human. The follow-up of the patient during the 5-year ART-free period, showed a relative stability of CD4+ cell count with a mean of 326 cells/μl. Initiation of cART led to rapid RNA undetectability with a significant increase of CD4+ cells, reaching 687 cells/μl after 8 years. CONCLUSION Our results showed that HIV-1/P strains remain extremely rare and could be less adapted and pathogenic than other HIV strains. These data lead to the hypothesis that HIV-1/P infection could evolve towards, or even already corresponds to, a dead-end infection.
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15
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Sauter D, Kirchhoff F. Multilayered and versatile inhibition of cellular antiviral factors by HIV and SIV accessory proteins. Cytokine Growth Factor Rev 2018. [PMID: 29526437 DOI: 10.1016/j.cytogfr.2018.02.005] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
HIV-1, the main causative agent of AIDS, and related primate lentiviruses show a striking ability to efficiently replicate throughout the lifetime of an infected host. In addition to their high variability, the acquisition of several accessory genes has enabled these viruses to efficiently evade or counteract seemingly strong antiviral immune responses. The respective viral proteins, i.e. Vif, Vpr, Vpu, Vpx and Nef, show a stunning functional diversity, acting by various mechanisms and targeting a large variety of cellular factors involved in innate and adaptive immunity. A focus of the present review is the accumulating evidence that Vpr, Vpu and Nef not only directly target cellular antiviral factors at the protein level, but also suppress their expression by modulating the activity of immune-regulatory transcription factors such as NF-κB. Furthermore, we will discuss the ability of accessory proteins to act as versatile adaptors, removing antiviral proteins from their sites of action and/or targeting them for proteasomal or endolysosomal degradation. Here, the main emphasis will be on emerging examples for functional interactions, synergisms and switches between accessory primate lentiviral proteins. A better understanding of this complex interplay between cellular immune defense mechanisms and viral countermeasures might facilitate the development of effective vaccines, help to prevent harmful chronic inflammation, and provide insights into the establishment and maintenance of latent viral reservoirs.
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Affiliation(s)
- Daniel Sauter
- Institute of Molecular Virology, Ulm University Medical Center, Meyerhofstr. 1, 89081 Ulm, Germany.
| | - Frank Kirchhoff
- Institute of Molecular Virology, Ulm University Medical Center, Meyerhofstr. 1, 89081 Ulm, Germany.
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16
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Foster TL, Pickering S, Neil SJD. Inhibiting the Ins and Outs of HIV Replication: Cell-Intrinsic Antiretroviral Restrictions at the Plasma Membrane. Front Immunol 2018; 8:1853. [PMID: 29354117 PMCID: PMC5758531 DOI: 10.3389/fimmu.2017.01853] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Accepted: 12/07/2017] [Indexed: 01/01/2023] Open
Abstract
Like all viruses, human immunodeficiency viruses (HIVs) and their primate lentivirus relatives must enter cells in order to replicate and, once produced, new virions need to exit to spread to new targets. These processes require the virus to cross the plasma membrane of the cell twice: once via fusion mediated by the envelope glycoprotein to deliver the viral core into the cytosol; and secondly by ESCRT-mediated scission of budding virions during release. This physical barrier thus presents a perfect location for host antiviral restrictions that target enveloped viruses in general. In this review we will examine the current understanding of innate host antiviral defences that inhibit these essential replicative steps of primate lentiviruses associated with the plasma membrane, the mechanism by which these viruses have adapted to evade such defences, and the role that this virus/host battleground plays in the transmission and pathogenesis of HIV/AIDS.
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Affiliation(s)
- Toshana L Foster
- Department of Infectious Disease, School of Immunology and Microbial Sciences, King's College London, London, United Kingdom
| | - Suzanne Pickering
- Department of Infectious Disease, School of Immunology and Microbial Sciences, King's College London, London, United Kingdom
| | - Stuart J D Neil
- Department of Infectious Disease, School of Immunology and Microbial Sciences, King's College London, London, United Kingdom
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17
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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: 72] [Impact Index Per Article: 10.3] [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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18
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Yi E, Oh J, Giao NQ, Oh S, Park SH. Enhanced production of enveloped viruses in BST-2-deficient cell lines. Biotechnol Bioeng 2017; 114:2289-2297. [PMID: 28498621 DOI: 10.1002/bit.26338] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 04/26/2017] [Accepted: 05/07/2017] [Indexed: 11/09/2022]
Abstract
Despite all the advantages that cell-cultured influenza vaccines have over egg-based influenza vaccines, the inferior productivity of cell-culture systems is a major drawback that must be addressed. BST-2 (tetherin) is a host restriction factor which inhibits budding-out of various enveloped viruses from infected host cells. We developed BST-2-deficient MDCK and Vero cell lines to increase influenza virus release in cell culture. BST-2 gene knock-out resulted in increased release of viral particles into the culture medium, by at least 2-fold and up to 50-fold compared to release from wild-type counterpart cells depending on cell line and virus type. The effect was not influenza virus/MDCK/Vero-specific, but was also present in a broad range of host cells and virus families; we observed similar results in murine, human, canine, and monkey cell lines with viruses including MHV-68 (Herpesviridae), influenza A virus (Orthomyxoviridae), porcine epidemic diarrhea virus (Coronaviridae), and vaccinia virus (Poxviridae). Our results suggest that the elimination of BST-2 expression in virus-producing cell lines can enhance the production of viral vaccines. Biotechnol. Bioeng.2017;114: 2289-2297. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Eunbi Yi
- College of Life Science and Biotechnology, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 02841, Republic of Korea.,ImmunoMax Co., Ltd, Korea University, Seongbuk-gu, Seoul, Republic of Korea
| | - Jinsoo Oh
- College of Life Science and Biotechnology, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 02841, Republic of Korea
| | - Ngoc Q Giao
- College of Life Science and Biotechnology, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 02841, Republic of Korea
| | - Soohwan Oh
- College of Life Science and Biotechnology, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 02841, Republic of Korea
| | - Se-Ho Park
- College of Life Science and Biotechnology, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 02841, Republic of Korea
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19
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Mack K, Starz K, Sauter D, Langer S, Bibollet-Ruche F, Learn GH, Stürzel CM, Leoz M, Plantier JC, Geyer M, Hahn BH, Kirchhoff F. Efficient Vpu-Mediated Tetherin Antagonism by an HIV-1 Group O Strain. J Virol 2017; 91:e02177-16. [PMID: 28077643 PMCID: PMC5331793 DOI: 10.1128/jvi.02177-16] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Accepted: 12/22/2016] [Indexed: 11/20/2022] Open
Abstract
Simian immunodeficiency viruses (SIVs) use their Nef proteins to counteract the restriction factor tetherin. However, a deletion in human tetherin prevents antagonism by the Nef proteins of SIVcpz and SIVgor, which represent the ape precursors of human immunodeficiency virus type 1 (HIV-1). To promote virus release from infected cells, pandemic HIV-1 group M strains evolved Vpu as a tetherin antagonist, while the Nef protein of less widespread HIV-1 group O strains acquired the ability to target a region adjacent to this deletion. In this study, we identified an unusual HIV-1 group O strain (RBF206) that evolved Vpu as an effective antagonist of human tetherin. While both RBF206 Vpu and Nef exert anti-tetherin activity in transient-transfection assays, mainly Vpu promotes RBF206 release in infected CD4+ T cells. Although mutations distinct from the adaptive changes observed in group M Vpus (M-Vpus) were critical for the acquisition of its anti-tetherin activity, RBF206 O-Vpu potently suppresses NF-κB activation and reduces CD4 cell surface expression. Interestingly, RBF206 Vpu counteracts tetherin in a largely species-independent manner, degrading both the long and short isoforms of human tetherin. Downmodulation of CD4, but not counteraction of tetherin, by RBF206 Vpu was dependent on the cellular ubiquitin ligase machinery. Our data present the first example of an HIV-1 group O Vpu that efficiently antagonizes human tetherin and suggest that counteraction by O-Nefs may be suboptimal.IMPORTANCE Previous studies showed that HIV-1 groups M and O evolved two alternative strategies to counteract the human ortholog of the restriction factor tetherin. While HIV-1 group M switched from Nef to Vpu due to a deletion in the cytoplasmic domain of human tetherin, HIV-1 group O, which lacks Vpu-mediated anti-tetherin activity, acquired a Nef protein that is able to target a region adjacent to the deletion. Here we report an unusual exception, identifying a strain of HIV-1 group O (RBF206) whose Vpu protein evolved an effective antagonism of human tetherin. Interestingly, the adaptive changes in RBF206 Vpu are distinct from those found in M-Vpus and mediate efficient counteraction of both the long and short isoforms of this restriction factor. Our results further illustrate the enormous flexibility of HIV-1 in counteracting human defense mechanisms.
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Affiliation(s)
- Katharina Mack
- Institute of Molecular Virology, Ulm University Medical Center, Ulm, Germany
| | - Kathrin Starz
- Institute of Molecular Virology, Ulm University Medical Center, Ulm, Germany
| | - Daniel Sauter
- Institute of Molecular Virology, Ulm University Medical Center, Ulm, Germany
| | - Simon Langer
- Institute of Molecular Virology, Ulm University Medical Center, Ulm, Germany
| | | | - Gerald H Learn
- Department of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Christina M Stürzel
- Institute of Molecular Virology, Ulm University Medical Center, Ulm, Germany
| | - Marie Leoz
- Laboratoire de Virologie, CHU Charles Nicolle, Rouen, France
- EA 2656 GRAM Université de Rouen, Rouen, France
| | - Jean-Christophe Plantier
- Laboratoire de Virologie, CHU Charles Nicolle, Rouen, France
- EA 2656 GRAM Université de Rouen, Rouen, France
- Laboratoire associé au Centre National de Référence du VIH, CHU Charles Nicolle, Rouen, France
| | - Matthias Geyer
- Department of Structural Immunology, Institute of Innate Immunity, University of Bonn, Bonn, Germany
| | - Beatrice H Hahn
- Department of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Department of Microbiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Frank Kirchhoff
- Institute of Molecular Virology, Ulm University Medical Center, Ulm, Germany
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20
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Neidleman JA, Chen JC, Kohgadai N, Müller JA, Laustsen A, Thavachelvam K, Jang KS, Stürzel CM, Jones JJ, Ochsenbauer C, Chitre A, Somsouk M, Garcia MM, Smith JF, Greenblatt RM, Münch J, Jakobsen MR, Giudice LC, Greene WC, Roan NR. Mucosal stromal fibroblasts markedly enhance HIV infection of CD4+ T cells. PLoS Pathog 2017; 13:e1006163. [PMID: 28207890 PMCID: PMC5312882 DOI: 10.1371/journal.ppat.1006163] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Accepted: 01/02/2017] [Indexed: 01/13/2023] Open
Abstract
Understanding early events of HIV transmission within mucosal tissues is vital for developing effective prevention strategies. Here, we report that primary stromal fibroblasts isolated from endometrium, cervix, foreskin, male urethra, and intestines significantly increase HIV infection of CD4+ T cells-by up to 37-fold for R5-tropic HIV and 100-fold for X4-tropic HIV-without themselves becoming infected. Fibroblasts were more efficient than dendritic cells at trans-infection and mediate this response in the absence of the DC-SIGN and Siglec-1 receptors. In comparison, mucosal epithelial cells secrete antivirals and inhibit HIV infection. These data suggest that breaches in the epithelium allow external or luminal HIV to escape an antiviral environment to access the infection-favorable environment of the stromal fibroblasts, and suggest that resident fibroblasts have a central, but previously unrecognized, role in HIV acquisition at mucosal sites. Inhibiting fibroblast-mediated enhancement of HIV infection should be considered as a novel prevention strategy.
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Affiliation(s)
- Jason A. Neidleman
- Gladstone Institute of Virology and Immunology, University of California, San Francisco, San Francisco, CA, United States of America
- Department of Urology, University of California, San Francisco, San Francisco, CA, United States of America
| | - Joseph C. Chen
- Center for Reproductive Sciences, Department of Obstetrics, Gynecology and Reproductive Sciences, University of California, San Francisco, San Francisco, CA, United States of America
| | - Nargis Kohgadai
- Gladstone Institute of Virology and Immunology, University of California, San Francisco, San Francisco, CA, United States of America
- Department of Urology, University of California, San Francisco, San Francisco, CA, United States of America
| | - Janis A. Müller
- Institute of Molecular Virology, Ulm University Medical Center, Ulm, Germany
| | - Anders Laustsen
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | | | - Karen S. Jang
- Gladstone Institute of Virology and Immunology, University of California, San Francisco, San Francisco, CA, United States of America
- Department of Urology, University of California, San Francisco, San Francisco, CA, United States of America
| | | | - Jennifer J. Jones
- Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Christina Ochsenbauer
- Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
- Center for AIDS Research, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Avantika Chitre
- Department of Medicine, Division of Experimental Medicine, University of California, San Francisco, San Francisco, CA, United States of America
| | - Ma Somsouk
- Department of Medicine, Division of Gastroenterology, San Francisco General Hospital and University of California, San Francisco, San Francisco, CA, United States of America
| | - Maurice M. Garcia
- Department of Urology, University of California, San Francisco, San Francisco, CA, United States of America
| | - James F. Smith
- Department of Urology, University of California, San Francisco, San Francisco, CA, United States of America
| | - Ruth M. Greenblatt
- Departments of Clinical Pharmacy, Medicine, Epidemiology and Biostatistics, University of California, San Francisco, San Francisco, CA United States of America
| | - Jan Münch
- Institute of Molecular Virology, Ulm University Medical Center, Ulm, Germany
| | - Martin R. Jakobsen
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
- Aarhus Research Centre for Innate Immunology, Aarhus University, Aarhus, Denmark
| | - Linda C. Giudice
- Center for Reproductive Sciences, Department of Obstetrics, Gynecology and Reproductive Sciences, University of California, San Francisco, San Francisco, CA, United States of America
| | - Warner C. Greene
- Gladstone Institute of Virology and Immunology, University of California, San Francisco, San Francisco, CA, United States of America
- Departments of Medicine, Microbiology, and Immunology, University of California, San Francisco, San Francisco, CA, United States of America
| | - Nadia R. Roan
- Gladstone Institute of Virology and Immunology, University of California, San Francisco, San Francisco, CA, United States of America
- Department of Urology, University of California, San Francisco, San Francisco, CA, United States of America
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21
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Soper A, Juarez-Fernandez G, Aso H, Moriwaki M, Yamada E, Nakano Y, Koyanagi Y, Sato K. Various plus unique: Viral protein U as a plurifunctional protein for HIV-1 replication. Exp Biol Med (Maywood) 2017; 242:850-858. [PMID: 28346011 DOI: 10.1177/1535370217697384] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Human immunodeficiency virus type 1 (HIV-1), the causative agent of acquired immunodeficiency syndrome, encodes four accessory genes, one of which is viral protein U (Vpu). Recently, the study of Vpu has been of great interest. For instance, various cellular proteins are degraded (e.g. CD4) and down-modulated (e.g. tetherin) by Vpu. Vpu also antagonizes the function of tetherin and inhibits NF-κB. Moreover, Vpu is a viroporin forming ion channels and may represent a promising target for anti-HIV-1 drugs. In this review, we summarize the domains/residues that are responsible for Vpu's functions, describe the current understanding of the role of Vpu in HIV-1-infected cells, and review the effect of Vpu on HIV-1 in replication and pathogenesis. Future investigations that simultaneously assess a combination of Vpu functions are required to clearly delineate the most important functions for viral replication. Impact statement Viral protein U (Vpu) is a unique protein encoded by human immunodeficiency virus type 1 (HIV-1) and related lentiviruses, playing multiple roles in viral replication and pathogenesis. In this review, we briefly summarize the most up-to-date knowledge of HIV-1 Vpu.
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Affiliation(s)
- Andrew Soper
- 1 Laboratory of Systems Virology, Department of Biosystems Science, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto 6068507, Japan
| | - Guillermo Juarez-Fernandez
- 1 Laboratory of Systems Virology, Department of Biosystems Science, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto 6068507, Japan
| | - Hirofumi Aso
- 1 Laboratory of Systems Virology, Department of Biosystems Science, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto 6068507, Japan.,2 Faculty of Pharmaceutical Sciences, Kyoto University, Kyoto 6068501, Japan
| | - Miyu Moriwaki
- 1 Laboratory of Systems Virology, Department of Biosystems Science, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto 6068507, Japan.,3 Graduate School of Biostudies, Kyoto University, Kyoto 6068315, Japan
| | - Eri Yamada
- 1 Laboratory of Systems Virology, Department of Biosystems Science, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto 6068507, Japan
| | - Yusuke Nakano
- 1 Laboratory of Systems Virology, Department of Biosystems Science, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto 6068507, Japan
| | - Yoshio Koyanagi
- 1 Laboratory of Systems Virology, Department of Biosystems Science, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto 6068507, Japan
| | - Kei Sato
- 1 Laboratory of Systems Virology, Department of Biosystems Science, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto 6068507, Japan.,4 CREST, Japan Science and Technology Agency, Saitama 3220012, Japan
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22
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Greiner T, Bolduan S, Hertel B, Groß C, Hamacher K, Schubert U, Moroni A, Thiel G. Ion Channel Activity of Vpu Proteins Is Conserved throughout Evolution of HIV-1 and SIV. Viruses 2016; 8:v8120325. [PMID: 27916968 PMCID: PMC5192386 DOI: 10.3390/v8120325] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Revised: 11/14/2016] [Accepted: 11/22/2016] [Indexed: 12/14/2022] Open
Abstract
The human immunodeficiency virus type 1 (HIV-1) protein Vpu is encoded exclusively by HIV-1 and related simian immunodeficiency viruses (SIVs). The transmembrane domain of the protein has dual functions: it counteracts the human restriction factor tetherin and forms a cation channel. Since these two functions are causally unrelated it remains unclear whether the channel activity has any relevance for viral release and replication. Here we examine structure and function correlates of different Vpu homologs from HIV-1 and SIV to understand if ion channel activity is an evolutionary conserved property of Vpu proteins. An electrophysiological testing of Vpus from different HIV-1 groups (N and P) and SIVs from chimpanzees (SIVcpz), and greater spot-nosed monkeys (SIVgsn) showed that they all generate channel activity in HEK293T cells. This implies a robust and evolutionary conserved channel activity and suggests that cation conductance may also have a conserved functional significance.
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Affiliation(s)
- Timo Greiner
- Membrane Biophysics, Technische Universität Darmstadt, 64287 Darmstadt, Germany.
| | - Sebastian Bolduan
- Institute of Virology, Helmholtz Zentrum Munich, 85764 Oberschleißheim, Germany.
| | - Brigitte Hertel
- Membrane Biophysics, Technische Universität Darmstadt, 64287 Darmstadt, Germany.
| | - Christine Groß
- Computational Biology & Simulation Group, Deparment of Biology, Technische Universität Darmstadt, 64287 Darmstadt, Germany.
| | - Kay Hamacher
- Computational Biology & Simulation Group, Deparment of Biology, Technische Universität Darmstadt, 64287 Darmstadt, Germany.
| | - Ulrich Schubert
- Institute of Virology, Friedrich Alexander University, 91054 Erlangen, Germany.
| | - Anna Moroni
- Department of Biology and CNR IBF-Mi, Università degli Studi di Milano, 20122 Milano, Italy.
| | - Gerhard Thiel
- Membrane Biophysics, Technische Universität Darmstadt, 64287 Darmstadt, Germany.
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23
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Richard M, Knauf S, Lawrence P, Mather AE, Munster VJ, Müller MA, Smith D, Kuiken T. Factors determining human-to-human transmissibility of zoonotic pathogens via contact. Curr Opin Virol 2016; 22:7-12. [PMID: 27907884 PMCID: PMC5346033 DOI: 10.1016/j.coviro.2016.11.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Revised: 11/02/2016] [Accepted: 11/11/2016] [Indexed: 01/25/2023]
Abstract
There are several modes of contact transmission of pathogens amongst humans. Factors promoting contact transmission act at the pathogen, host or environmental levels. Common pathogen factors are immune evasion, high viral load and low infectious dose. Common host factors are crowding, promiscuity and the presence of co-infections.
The pandemic potential of zoonotic pathogens lies in their ability to become efficiently transmissible amongst humans. Here, we focus on contact-transmitted pathogens and discuss the factors, at the pathogen, host and environmental levels that promote or hinder their human-to-human transmissibility via the following modes of contact transmission: skin contact, sexual contact, respiratory contact and multiple route contact. Factors common to several modes of transmission were immune evasion, high viral load, low infectious dose, crowding, promiscuity, and co-infections; other factors were specific for a pathogen or mode of contact transmission. The identification of such factors will lead to a better understanding of the requirements for human-to-human spread of pathogens, as well as improving risk assessment of newly emerging pathogens.
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Affiliation(s)
- Mathilde Richard
- Department of Viroscience, Postgraduate School Molecular Medicine, Erasmus MC, Rotterdam, The Netherlands
| | - Sascha Knauf
- Work Group Neglected Tropical Diseases, German Primate Center, Leibniz-Institute for Primate Research, Göttingen, Germany
| | - Philip Lawrence
- Université de Lyon, UMRS 449, Laboratoire de Biologie Générale, Université Catholique de Lyon - EPHE, Lyon 69288, France; Molecular Basis of Viral Pathogenicity, International Centre for Research in Infectiology (CIRI), INSERM U1111 - CNRS UMR5308, Université Lyon 1, Ecole Normale Supérieure de Lyon, Lyon 69007, France
| | - Alison E Mather
- Department of Veterinary Medicine, University of Cambridge, Cambridge, UK
| | - Vincent J Munster
- Virus Ecology Unit, Laboratory of Virology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rocky Mountain Laboratories, Hamilton, MT, USA
| | - Marcel A Müller
- Institute of Virology, University of Bonn Medical Center, Bonn, Germany
| | - Derek Smith
- Department of Zoology, University of Cambridge, Cambridge, UK
| | - Thijs Kuiken
- Department of Viroscience, Postgraduate School Molecular Medicine, Erasmus MC, Rotterdam, The Netherlands.
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Abstract
PURPOSE OF REVIEW The goal of this review is to summarize recent progress in our understanding of innate sensing of HIV. Furthermore, we present the mechanisms that HIV has evolved to attenuate innate immune responses and discuss open questions. RECENT FINDINGS Toll-like receptors (TLRs) and various cytosolic sensors induce an antiviral interferon response upon detection of genomic HIV RNA or intermediates of reverse transcription. HIV limits activation of these sensing pathways by interfering with TLR signaling and by cloaking viral nucleic acids in the cytoplasm, before proviral dsDNA translocates into the nucleus. Furthermore, the viral accessory protein Vpu mitigates antiviral gene expression by inhibiting canonical nuclear factor kappa B (NF-κB) signaling. These evasion mechanisms, however, are imperfect and HIV infection almost inevitably triggers the activation of IRF3, NF-κB and other key transcription factors of antiviral immunity. Notably, the interplay of these processes plays a critical role in the induction of chronic inflammation that drives progression to AIDS. SUMMARY HIV has evolved sophisticated but imperfect mechanisms to evade and counteract innate sensing. Whether virus-induced immune activation represents merely a suboptimal adaptation of HIV to its human host or even facilitates HIV replication, for example by increasing the number of viral target cells, remains to be clarified.
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Abstract
Human immunodeficiency virus type 1 (HIV-1) groups M, N, O, and P are the result of independent zoonotic transmissions of simian immunodeficiency viruses (SIVs) infecting great apes in Africa. Among these, only Vpu proteins of pandemic HIV-1 group M strains evolved potent activity against the restriction factor tetherin, which inhibits virus release from infected cells. Thus, effective Vpu-mediated tetherin antagonism may have been a prerequisite for the global spread of HIV-1. To determine whether this particular function enhances primary HIV-1 replication and interferon resistance, we introduced mutations into the vpu genes of HIV-1 group M and N strains to specifically disrupt their ability to antagonize tetherin, but not other Vpu functions, such as degradation of CD4, down-modulation of CD1d and NTB-A, and suppression of NF-κB activity. Lack of particular human-specific adaptations reduced the ability of HIV-1 group M Vpu proteins to enhance virus production and release from primary CD4+ T cells at high levels of type I interferon (IFN) from about 5-fold to 2-fold. Interestingly, transmitted founder HIV-1 strains exhibited higher virion release capacity than chronic control HIV-1 strains irrespective of Vpu function, and group M viruses produced higher levels of cell-free virions than an N group HIV-1 strain. Thus, efficient virus release from infected cells seems to play an important role in the spread of HIV-1 in the human population and requires a fully functional Vpu protein that counteracts human tetherin. Understanding which human-specific adaptations allowed HIV-1 to cause the AIDS pandemic is of great importance. One feature that distinguishes pandemic HIV-1 group M strains from nonpandemic or rare group O, N, and P viruses is the acquisition of mutations in the accessory Vpu protein that confer potent activity against human tetherin. Adaptation was required because human tetherin has a deletion that renders it resistant to the Nef protein used by the SIV precursor of HIV-1 to antagonize this antiviral factor. It has been suggested that these adaptations in Vpu were critical for the effective spread of HIV-1 M strains, but direct evidence has been lacking. Here, we show that these changes in Vpu significantly enhance virus replication and release in human CD4+ T cells, particularly in the presence of IFN, thus supporting an important role in the spread of pandemic HIV-1.
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Vpu Protein: The Viroporin Encoded by HIV-1. Viruses 2015; 7:4352-68. [PMID: 26247957 PMCID: PMC4576185 DOI: 10.3390/v7082824] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Revised: 06/29/2015] [Accepted: 07/28/2015] [Indexed: 02/06/2023] Open
Abstract
Viral protein U (Vpu) is a lentiviral viroporin encoded by human immunodeficiency virus type 1 (HIV-1) and some simian immunodeficiency virus (SIV) strains. This small protein of 81 amino acids contains a single transmembrane domain that allows for supramolecular organization via homoligomerization or interaction with other proteins. The topology and trafficking of Vpu through subcellular compartments result in pleiotropic effects in host cells. Notwithstanding the high variability of its amino acid sequence, the functionality of Vpu is well conserved in pandemic virus isolates. This review outlines our current knowledge on the interactions of Vpu with the host cell. The regulation of cellular physiology by Vpu and the validity of this viroporin as a therapeutic target are also discussed.
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Iwami S, Sato K, Morita S, Inaba H, Kobayashi T, Takeuchi JS, Kimura Y, Misawa N, Ren F, Iwasa Y, Aihara K, Koyanagi Y. Pandemic HIV-1 Vpu overcomes intrinsic herd immunity mediated by tetherin. Sci Rep 2015; 5:12256. [PMID: 26184634 PMCID: PMC4505337 DOI: 10.1038/srep12256] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Accepted: 06/23/2015] [Indexed: 12/26/2022] Open
Abstract
Among the four groups of HIV-1 (M, N, O, and P), HIV-1M alone is pandemic and has rapidly expanded across the world. However, why HIV-1M has caused a devastating pandemic while the other groups remain contained is unclear. Interestingly, only HIV-1M Vpu, a viral protein, can robustly counteract human tetherin, which tethers budding virions. Therefore, we hypothesize that this property of HIV-1M Vpu facilitates human-to-human viral transmission. Adopting a multilayered experimental-mathematical approach, we demonstrate that HIV-1M Vpu confers a 2.38-fold increase in the prevalence of HIV-1 transmission. When Vpu activity is lost, protected human populations emerge (i.e., intrinsic herd immunity develops) through the anti-viral effect of tetherin. We also reveal that all Vpus of transmitted/founder HIV-1M viruses maintain anti-tetherin activity. These findings indicate that tetherin plays the role of a host restriction factor, providing ‘intrinsic herd immunity’, whereas Vpu has evolved in HIV-1M as a tetherin antagonist.
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Affiliation(s)
- Shingo Iwami
- 1] Mathematical Biology Laboratory, Department of Biology, Faculty of Sciences, Kyushu University, Fukuoka, Fukuoka 8128581, Japan [2] PRESTO, JST, Kawaguchi, Saitama 3320012, Japan [3] CREST, JST, Kawaguchi, Saitama 3320012, Japan
| | - Kei Sato
- 1] Laboratory of Viral Pathogenesis, Institute for Virus Research, Kyoto University, Kyoto, Kyoto 6068507, Japan [2] CREST, JST, Kawaguchi, Saitama 3320012, Japan
| | - Satoru Morita
- 1] Department of Mathematical and Systems Engineering, Shizuoka University, Hamamatsu, Shizuoka 4328561, Japan [2] CREST, JST, Kawaguchi, Saitama 3320012, Japan
| | - Hisashi Inaba
- 1] Graduate School of Mathematical Sciences, The University of Tokyo, Meguro-ku, Tokyo 1538914, Japan [2] CREST, JST, Kawaguchi, Saitama 3320012, Japan
| | - Tomoko Kobayashi
- Laboratory for Animal Health, Department of Animal Science, Faculty of Agriculture, Tokyo University of Agriculture, Atsugi, Kanagawa 2430034, Japan
| | - Junko S Takeuchi
- Laboratory of Viral Pathogenesis, Institute for Virus Research, Kyoto University, Kyoto, Kyoto 6068507, Japan
| | - Yuichi Kimura
- Laboratory of Viral Pathogenesis, Institute for Virus Research, Kyoto University, Kyoto, Kyoto 6068507, Japan
| | - Naoko Misawa
- Laboratory of Viral Pathogenesis, Institute for Virus Research, Kyoto University, Kyoto, Kyoto 6068507, Japan
| | - Fengrong Ren
- Department of Bioinformatics, Medical Research Institute, Tokyo Medical and Dental University, Tokyo 1138510, Japan
| | - Yoh Iwasa
- Mathematical Biology Laboratory, Department of Biology, Faculty of Sciences, Kyushu University, Fukuoka, Fukuoka 8128581, Japan
| | - Kazuyuki Aihara
- 1] Institute of Industrial Science, The University of Tokyo, Meguro-ku, Tokyo 1538505, Japan [2] Graduate School of Information Science and Technology, The University of Tokyo, Meguro-ku, Tokyo 1138656, Japan
| | - Yoshio Koyanagi
- Laboratory of Viral Pathogenesis, Institute for Virus Research, Kyoto University, Kyoto, Kyoto 6068507, Japan
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HIV Vpu Interferes with NF-κB Activity but Not with Interferon Regulatory Factor 3. J Virol 2015; 89:9781-90. [PMID: 26178989 DOI: 10.1128/jvi.01596-15] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Accepted: 07/09/2015] [Indexed: 01/24/2023] Open
Abstract
UNLABELLED The accessory HIV protein Vpu inhibits a number of cellular pathways that trigger host innate restriction mechanisms. HIV Vpu-mediated degradation of tetherin allows efficient particle release and hampers the activation of the NF-κB pathway thereby limiting the expression of proinflammatory genes. In addition, Vpu reduces cell surface expression of several cellular molecules such as newly synthesized CD4. However, the role of HIV Vpu in regulating the type 1 interferon response to viral infection by degradation of the interferon regulatory factor 3 (IRF3) has been subject of conflicting reports. We therefore systematically investigated the expression of IRF3 in primary CD4(+) T cells and macrophages infected with HIV at different time points. In addition, we also tested the ability of Vpu to interfere with innate immune signaling pathways such as the NF-κB and the IRF3 pathways. We report here that HIV Vpu failed to degrade IRF3 in infected primary cells. Moreover, we observed that HIV NL4.3 Vpu had no effect on IRF3-dependent gene expression in reporter assays. On the other hand, HIV NL4.3 Vpu downmodulated NF-κB-dependent transcription. Mutation of two serines (positions 52 and 56) involved in the binding of NL4.3 Vpu to the βTrCP ubiquitin ligase abolishes its ability to inhibit NF-κB activity. Taken together, these results suggest that HIV Vpu regulates antiviral innate response in primary human cells by acting specifically on the NF-κB pathway. IMPORTANCE HIV Vpu plays a pivotal role in enhancing HIV infection by counteraction of Tetherin. However, Vpu also regulates host response to HIV infection by hampering the type 1 interferon response. The molecular mechanism by which Vpu inhibits the interferon response is still controversial. Here we report that Vpu affects interferon expression by inhibiting NF-κB activity without affecting IRF3 levels or activity. These data suggest that Vpu facilitates HIV infection by regulating NF-κB transcription to levels sufficient for viral transcription while limiting cellular responses to infection.
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Involvement of a C-terminal motif in the interference of primate lentiviral Vpu proteins with CD1d-mediated antigen presentation. Sci Rep 2015; 5:9675. [PMID: 25872908 PMCID: PMC4397644 DOI: 10.1038/srep09675] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2014] [Accepted: 03/16/2015] [Indexed: 01/01/2023] Open
Abstract
The HIV-1 accessory protein Vpu is emerging as a critical factor for viral evasion from innate immunity. We have previously shown that the Vpu proteins of two HIV-1 group M subtype B strains (NL4-3 and BaL) down-regulate CD1d from the surface of infected dendritic cells (DCs) and inhibit their crosstalk with the innate invariant natural killer T (iNKT) cells. In the present study, we have investigated the ability of a comprehensive set of primate lentiviral Vpu proteins to interfere with CD1d-mediated immunity. We found that CD1d down-regulation is a conserved function of Vpu proteins from HIV-1 groups M, O and P as well as their direct precursors SIVcpzPtt and SIVgor. At the group M subtype level, subtype C Vpu proteins were significantly weaker CD1d antagonists than subtype B Vpu proteins. Functional characterization of different mutants and chimeras derived from active subtype B and inactive subtype C Vpu proteins revealed that residues in the cytoplasmic domain are important for CD1d down-regulation. Specifically, we identified a C-terminal APW motif characteristic for group M subtype B Vpu proteins necessary for interference with CD1d surface expression. These findings support the notion that Vpu plays an important role in lentiviral evasion from innate immunity.
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Yamada E, Yoshikawa R, Nakano Y, Misawa N, Koyanagi Y, Sato K. Impacts of humanized mouse models on the investigation of HIV-1 infection: illuminating the roles of viral accessory proteins in vivo. Viruses 2015; 7:1373-90. [PMID: 25807049 PMCID: PMC4379576 DOI: 10.3390/v7031373] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Revised: 03/10/2015] [Accepted: 03/10/2015] [Indexed: 12/26/2022] Open
Abstract
Human immunodeficiency virus type 1 (HIV-1) encodes four accessory genes: vif, vpu, vpr, and nef. Recent investigations using in vitro cell culture systems have shed light on the roles of these HIV-1 accessory proteins, Vif, Vpr, Vpu, and Nef, in counteracting, modulating, and evading various cellular factors that are responsible for anti-HIV-1 intrinsic immunity. However, since humans are the exclusive target for HIV-1 infection, conventional animal models are incapable of mimicking the dynamics of HIV-1 infection in vivo. Moreover, the effects of HIV-1 accessory proteins on viral infection in vivo remain unclear. To elucidate the roles of HIV-1 accessory proteins in the dynamics of viral infection in vivo, humanized mouse models, in which the mice are xenotransplanted with human hematopoietic stem cells, has been utilized. This review describes the current knowledge of the roles of HIV-1 accessory proteins in viral infection, replication, and pathogenicity in vivo, which are revealed by the studies using humanized mouse models.
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Affiliation(s)
- Eri Yamada
- Laboratory of Viral Pathogenesis, Institute for Virus Research, Kyoto University, Kyoto 6068507, Japan.
| | - Rokusuke Yoshikawa
- Laboratory of Viral Pathogenesis, Institute for Virus Research, Kyoto University, Kyoto 6068507, Japan.
| | - Yusuke Nakano
- Laboratory of Viral Pathogenesis, Institute for Virus Research, Kyoto University, Kyoto 6068507, Japan.
| | - Naoko Misawa
- Laboratory of Viral Pathogenesis, Institute for Virus Research, Kyoto University, Kyoto 6068507, Japan.
| | - Yoshio Koyanagi
- Laboratory of Viral Pathogenesis, Institute for Virus Research, Kyoto University, Kyoto 6068507, Japan.
| | - Kei Sato
- Laboratory of Viral Pathogenesis, Institute for Virus Research, Kyoto University, Kyoto 6068507, Japan.
- CREST, Japan Science and Technology Agency, Saitama 3220012, Japan.
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Kluge SF, Mack K, Iyer SS, Pujol FM, Heigele A, Learn GH, Usmani SM, Sauter D, Joas S, Hotter D, Bibollet-Ruche F, Plenderleith LJ, Peeters M, Geyer M, Sharp PM, Fackler OT, Hahn BH, Kirchhoff F. Nef proteins of epidemic HIV-1 group O strains antagonize human tetherin. Cell Host Microbe 2014; 16:639-50. [PMID: 25525794 PMCID: PMC4274627 DOI: 10.1016/j.chom.2014.10.002] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Revised: 08/13/2014] [Accepted: 09/18/2014] [Indexed: 01/06/2023]
Abstract
Most simian immunodeficiency viruses use their Nef protein to antagonize the host restriction factor tetherin. A deletion in human tetherin confers Nef resistance, representing a hurdle to successful zoonotic transmission. HIV-1 group M evolved to utilize the viral protein U (Vpu) to counteract tetherin. Although HIV-1 group O has spread epidemically in humans, it has not evolved a Vpu-based tetherin antagonism. Here we show that HIV-1 group O Nef targets a region adjacent to this deletion to inhibit transport of human tetherin to the cell surface, enhances virion release, and increases viral resistance to inhibition by interferon-α. The Nef protein of the inferred common ancestor of group O viruses is also active against human tetherin. Thus, Nef-mediated antagonism of human tetherin evolved prior to the spread of HIV-1 group O and likely facilitated secondary virus transmission. Our results may explain the epidemic spread of HIV-1 group O.
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Affiliation(s)
- Silvia F Kluge
- Institute of Molecular Virology, Ulm University Medical Center, 89081 Ulm, Germany
| | - Katharina Mack
- Institute of Molecular Virology, Ulm University Medical Center, 89081 Ulm, Germany
| | - Shilpa S Iyer
- Departments of Medicine and Microbiology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - François M Pujol
- Department of Infectious Diseases, Integrative Virology, University Hospital Heidelberg, 69120 Heidelberg, Germany
| | - Anke Heigele
- Institute of Molecular Virology, Ulm University Medical Center, 89081 Ulm, Germany
| | - Gerald H Learn
- Departments of Medicine and Microbiology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Shariq M Usmani
- Institute of Molecular Virology, Ulm University Medical Center, 89081 Ulm, Germany
| | - Daniel Sauter
- Institute of Molecular Virology, Ulm University Medical Center, 89081 Ulm, Germany
| | - Simone Joas
- Institute of Molecular Virology, Ulm University Medical Center, 89081 Ulm, Germany
| | - Dominik Hotter
- Institute of Molecular Virology, Ulm University Medical Center, 89081 Ulm, Germany
| | - Frederic Bibollet-Ruche
- Departments of Medicine and Microbiology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | | | - Martine Peeters
- UMI233, TransVIHMI, Institut de Recherche pour le Développement (IRD) and Université Montpellier, Montpellier 34394, France
| | - Matthias Geyer
- Group Physical Biochemistry, Center of Advanced European Studies and Research, 53175 Bonn, Germany
| | - Paul M Sharp
- Institute of Evolutionary Biology, University of Edinburgh, Edinburgh EH9 3JT, UK
| | - Oliver T Fackler
- Department of Infectious Diseases, Integrative Virology, University Hospital Heidelberg, 69120 Heidelberg, Germany
| | - Beatrice H Hahn
- Departments of Medicine and Microbiology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
| | - Frank Kirchhoff
- Institute of Molecular Virology, Ulm University Medical Center, 89081 Ulm, Germany.
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Bolduan S, Reif T, Schindler M, Schubert U. HIV-1 Vpu mediated downregulation of CD155 requires alanine residues 10, 14 and 18 of the transmembrane domain. Virology 2014; 464-465:375-384. [PMID: 25113908 DOI: 10.1016/j.virol.2014.07.034] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Revised: 05/19/2014] [Accepted: 07/21/2014] [Indexed: 10/24/2022]
Abstract
HIV-1 NL4-3 Vpu induces downregulation of cell surface CD155, a ligand for the DNAM-1 activating receptor of NK and CD8(+) T cells, to evade NK cell mediated immune response. Here we show that the conserved alanine residues at positions 10, 14 and 18 in the TM domain of Vpu are required for the efficient downregulation of cell surface CD155. In contrast, the CK-2 phosphorylation sites and the second α-helix in the cytoplasmic Vpu domain have no influence on the surface expression of CD155. Thus, compared to Vpu׳s effect on CD4, NTB-A and tetherin, the Vpu mediated downregulation of CD155 is an independent Vpu function. We finally show that in contrast to other lentiviral strains, only Vpu and Nef from HIV-1 M NL4-3 potently interfere with CD155 surface expression. Thus, Vpu seems to subvert NK cell responses against HIV-1 infected T cells by modulation of receptors necessary for NK cell activation.
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Affiliation(s)
- Sebastian Bolduan
- Institute of Virology, University of Erlangen-Nuremberg, Germany; Institute of Virology, Helmholtz Zentrum Munich, Germany.
| | - Tatjana Reif
- Institute of Virology, University of Erlangen-Nuremberg, Germany.
| | - Michael Schindler
- Institute of Virology, Helmholtz Zentrum Munich, Germany; Institute of Medical Virology and Epidemiology of Viral Diseases, University Clinic Tübingen, Germany.
| | - Ulrich Schubert
- Institute of Virology, University of Erlangen-Nuremberg, Germany.
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Giese S, Marsh M. Tetherin can restrict cell-free and cell-cell transmission of HIV from primary macrophages to T cells. PLoS Pathog 2014; 10:e1004189. [PMID: 24991932 PMCID: PMC4081785 DOI: 10.1371/journal.ppat.1004189] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2013] [Accepted: 05/02/2014] [Indexed: 11/19/2022] Open
Abstract
Bst-2/Tetherin inhibits the release of HIV by tethering newly formed virus particles to the plasma membrane of infected cells. Although the mechanisms of Tetherin-mediated restriction are increasingly well understood, the biological relevance of this restriction in the natural target cells of HIV is unclear. Moreover, whether Tetherin exerts any restriction on the direct cell-cell spread of HIV across intercellular contacts remains controversial. Here we analyse the restriction endogenous Tetherin imposes on HIV transmission from primary human macrophages, one of the main targets of HIV in vivo. We find that the mRNA and protein levels of Tetherin in macrophages are comparable to those in T cells from the same donors, and are highly upregulated by type I interferons. Improved immunocytochemistry protocols enable us to demonstrate that Tetherin localises to the cell surface, the trans-Golgi network, and the macrophage HIV assembly compartments. Tetherin retains budded virions in the assembly compartments, thereby impeding the release and cell-free spread of HIV, but it is not required for the maintenance of these compartments per se. Notably, using a novel assay to quantify cell-cell spread, we show that Tetherin promotes the transfer of virus clusters from macrophages to T cells and thereby restricts the direct transmission of a dual-tropic HIV-1. Kinetic analyses provide support for the notion that this direct macrophage-T cell spread is mediated, at least in part, by so-called virological synapses. Finally, we demonstrate that the viral Vpu protein efficiently downregulates the cell surface and overall levels of Tetherin, and thereby abrogates this HIV restriction in macrophages. Together, our study shows that Tetherin, one of the most potent HIV restriction factors identified to date, can inhibit virus spread from primary macrophages, regardless of the mode of transmission.
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Affiliation(s)
- Sebastian Giese
- MRC/UCL Laboratory for Molecular Cell Biology, University College London, London, United Kingdom
| | - Mark Marsh
- MRC/UCL Laboratory for Molecular Cell Biology, University College London, London, United Kingdom
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Sauter D. Counteraction of the multifunctional restriction factor tetherin. Front Microbiol 2014; 5:163. [PMID: 24782851 PMCID: PMC3989765 DOI: 10.3389/fmicb.2014.00163] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Accepted: 03/26/2014] [Indexed: 01/28/2023] Open
Abstract
The interferon-inducible restriction factor tetherin (also known as CD317, BST-2 or HM1.24) has emerged as a key component of the antiviral immune response. Initially, tetherin was shown to restrict replication of various enveloped viruses by inhibiting the release of budding virions from infected cells. More recently, it has become clear that tetherin also acts as a pattern recognition receptor inducing NF-κB-dependent proinflammatory gene expression in virus infected cells. Whereas the ability to restrict virion release is highly conserved among mammalian tetherin orthologs and thus probably an ancient function of this protein, innate sensing seems to be an evolutionarily recent activity. The potent and broad antiviral activity of tetherin is reflected by the fact that many viruses evolved means to counteract this restriction factor. A continuous arms race with viruses has apparently driven the evolution of different isoforms of tetherin with different functional properties. Interestingly, tetherin has also been implicated in cellular processes that are unrelated to immunity, such as the organization of the apical actin network and membrane microdomains or stabilization of the Golgi apparatus. In this review, I summarize our current knowledge of the different functions of tetherin and describe the molecular strategies that viruses have evolved to antagonize or evade this multifunctional host restriction factor.
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Affiliation(s)
- Daniel Sauter
- Institute of Molecular Virology, Ulm University Medical Center Ulm, Germany
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Pickering S, Hué S, Kim EY, Reddy S, Wolinsky SM, Neil SJD. Preservation of tetherin and CD4 counter-activities in circulating Vpu alleles despite extensive sequence variation within HIV-1 infected individuals. PLoS Pathog 2014; 10:e1003895. [PMID: 24465210 PMCID: PMC3900648 DOI: 10.1371/journal.ppat.1003895] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2013] [Accepted: 12/06/2013] [Indexed: 01/19/2023] Open
Abstract
The HIV-1 Vpu protein is expressed from a bi-cistronic message late in the viral life cycle. It functions during viral assembly to maximise infectious virus release by targeting CD4 for proteosomal degradation and counteracting the antiviral protein tetherin (BST2/CD317). Single genome analysis of vpu repertoires throughout infection in 14 individuals infected with HIV-1 clade B revealed extensive amino acid diversity of the Vpu protein. For the most part, this variation in Vpu increases over the course of infection and is associated with predicted epitopes of the individual's MHC class I haplotype, suggesting CD8+ T cell pressure is the major driver of Vpu sequence diversity within the host. Despite this variability, the Vpu functions of targeting CD4 and counteracting both physical virus restriction and NF-κB activation by tetherin are rigorously maintained throughout HIV-1 infection. Only a minority of circulating alleles bear lesions in either of these activities at any given time, suggesting functional Vpu mutants are heavily selected against even at later stages of infection. Comparison of Vpu proteins defective for one or several functions reveals novel determinants of CD4 downregulation, counteraction of tetherin restriction, and inhibition of NF-κB signalling. These data affirm the importance of Vpu functions for in vivo persistence of HIV-1 within infected individuals, not simply for transmission, and highlight its potential as a target for antiviral therapy. The accessory protein Vpu, encoded by HIV-1, performs at least two major roles in the virus life cycle, namely the degradation of newly synthesized CD4 molecules and the counteraction of a host antiviral protein, tetherin. These activities promote the release of infectious viruses from host cells, and recent evidence suggests that Vpu function has been crucial for the cross-species transmission of HIV-1 from chimpanzees, and its subsequent pandemic spread in humans. Here we studied the functional variation in Vpu in infected individuals. We found that the Vpu amino acid sequence can be highly variable within an individual, and that this variation is likely to result from host immune responses targeting antigens derived from Vpu. However, despite this variation, Vpu's major functions are preserved, with only a minority of circulating alleles showing defects throughout the course of infection. These data suggest that defective Vpu proteins are selected against within the infected individual, implying that Vpu functions are critical for HIV-1 replication throughout natural infection, not simply at transmission. Therefore Vpu may represent a novel target for antiviral therapy to augment current treatment strategies for HIV/AIDS.
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Affiliation(s)
- Suzanne Pickering
- Department of Infectious Disease, King's College School of Medicine, Guy's Hospital, London, United Kingdom
| | - Stephane Hué
- MRC Centre for Medical Molecular Virology, University College London, London, United Kingdom
| | - Eun-Young Kim
- Department of Medicine, Northwestern University, Chicago, Illinois, United States of America
| | - Susheel Reddy
- Department of Medicine, Northwestern University, Chicago, Illinois, United States of America
| | - Steven M. Wolinsky
- Department of Medicine, Northwestern University, Chicago, Illinois, United States of America
| | - Stuart J. D. Neil
- Department of Infectious Disease, King's College School of Medicine, Guy's Hospital, London, United Kingdom
- * E-mail:
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Abstract
The AIDS pandemic that started in the early 1980s is due to human immunodeficiency virus type 1 (HIV-1) group M (HIV-M), but apart from this major group, many divergent variants have been described (HIV-1 groups N, O, and P and HIV-2). The four HIV-1 groups arose from independent cross-species transmission of the simian immunodeficiency viruses (SIVs) SIVcpz, infecting chimpanzees, and SIVgor, infecting gorillas. This, together with human adaptation, accounts for their genomic, phylogenetic, and virological specificities. Nevertheless, the natural course of non-M HIV infection seems similar to that of HIV-M. The virological monitoring of infected patients is now possible with commercial kits, but their therapeutic management remains complex. All non-M variants were principally described for patients linked to Cameroon, where HIV-O accounts for 1% of all HIV infections; only 15 cases of HIV-N infection and 2 HIV-P infections have been reported. Despite improvements in our knowledge, many fascinating questions remain concerning the origin, genetic evolution, and slow spread of these variants. Other variants may already exist or may arise in the future, calling for close surveillance. This review provides a comprehensive, up-to-date summary of the current knowledge on these pathogens, including the historical background of their discovery; the latest advances in the comprehension of their origin and spread; and clinical, therapeutic, and laboratory aspects that may be useful for the management and the treatment of patients infected with these divergent viruses.
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Peeters M, Jung M, Ayouba A. The origin and molecular epidemiology of HIV. Expert Rev Anti Infect Ther 2014; 11:885-96. [DOI: 10.1586/14787210.2013.825443] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Peeters M, D’Arc M, Delaporte E. Origin and diversity of human retroviruses. AIDS Rev 2014; 16:23-34. [PMID: 24584106 PMCID: PMC4289907] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Simian immunodeficiency viruses, simian T‑cell lymphotropic viruses, and simian foamy viruses from nonhuman primates have crossed the species barrier to humans at several time points, leading to the HIV and human T lymphotropic virus epidemic and to sporadic cases of human infections with simian foamy viruses, respectively. Efficient infection and spread in humans differs between simian foamy virus, simian lymphotropic virus, and simian immunodeficiency virus, but seems also to differ among the different viruses from the same simian lineage, as illustrated by the different spread of HIV‑1 M, N O, P or for the different HIV‑2 groups. Among the four HIV‑1 groups, only HIV‑1 group M has spread worldwide, and the actual diversity within HIV‑1 M (subtypes, circulating recombinants) is the result of subsequent evolution and spread in the human population. HIV‑2 only spread to some extent in West Africa, and similarly as for HIV‑1, the nine HIV‑2 groups have also a different epidemic history. Four types of human T lymphotropic virus, type 1 to 4, have been described in humans and for three of them simian counterparts (simian T lymphotropic virus‑1, ‑2, ‑3) have been identified in multiple nonhuman primate species. The majority of human infections are with human T lymphotropic virus‑1, which is present throughout the world as clusters of high endemicity. Humans are susceptible to a wide variety of simian foamy viruses and seem to acquire these viruses more readily than simian immunodeficiency viruses or simian T lymphotropic viruses, but neither signs of disease in humans nor human‑to‑human transmission of simian foamy virus have been documented yet. The current HIV‑1 M epidemic illustrates the impact of a single cross‑species transmission. The recent discovery of HIV‑1 P, HIV‑2 I, new human T lymphotropic virus‑1 and ‑3 variants, as well as simian foamy virus infections in humans in Central Africa, show that our knowledge of genetic diversity and cross‑species transmissions of simian retroviruses is still incomplete.
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Affiliation(s)
- Martine Peeters
- UMI 233, Institut de Recherche pour le Développement (IRD) and University of Montpellier 1, Montpellier, France
- Computational Biology Institute, Montpellier, France
| | - Mirela D’Arc
- UMI 233, Institut de Recherche pour le Développement (IRD) and University of Montpellier 1, Montpellier, France
- Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil
| | - Eric Delaporte
- UMI 233, Institut de Recherche pour le Développement (IRD) and University of Montpellier 1, Montpellier, France
- Universitary Hospital Gui de Chauliac, Montpellier, France
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Emerging Role of the Host Restriction Factor Tetherin in Viral Immune Sensing. J Mol Biol 2013; 425:4956-64. [DOI: 10.1016/j.jmb.2013.09.029] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Revised: 09/20/2013] [Accepted: 09/22/2013] [Indexed: 12/22/2022]
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Sauter D, Hotter D, Engelhart S, Giehler F, Kieser A, Kubisch C, Kirchhoff F. A rare missense variant abrogates the signaling activity of tetherin/BST-2 without affecting its effect on virus release. Retrovirology 2013; 10:85. [PMID: 23937976 PMCID: PMC3751106 DOI: 10.1186/1742-4690-10-85] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2013] [Accepted: 08/06/2013] [Indexed: 01/21/2023] Open
Abstract
Background Tetherin (or BST-2) is an antiviral host restriction factor that suppresses the release of HIV-1 and other enveloped viruses by tethering them to the cell surface. Recently, it has been demonstrated that tetherin also acts as an innate sensor of HIV-1 assembly that induces NF-κB-dependent proinflammatory responses. Furthermore, it has been reported that polymorphisms in the promoter and 3‘ untranslated region of the bst2 gene may affect the clinical outcome of HIV-1 infection. However, non-synonymous polymorphisms in the bst2 open reading frame have not yet been described or functionally characterized. Results Mining of the Exome Variant Server database identified seven very rare naturally occurring missense variants of tetherin (Y8H, R19H, N49S, D103N, E117A, D129E and V146L) in human populations. Functional analyses showed that none of these sequence variants significantly affects the ability of tetherin to inhibit HIV-1 virion release or its sensitivity to antagonism by HIV-1 Vpu or SIVtan Env, although Y8H alters a potential YxY endocytic motif proposed to play a role in virion uptake. Thus, these variants do most likely not represent an evolutionary advantage in directly controlling HIV-1 replication or spread. Interestingly, however, the R19H variant selectively abrogated the signaling activity of tetherin. Conclusions Restriction of HIV-1 virion release and immune sensing are two separable functions of human tetherin and the latter activity is severely impaired by a single amino acid variant (R19H) in the cytoplasmic part of tetherin.
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Affiliation(s)
- Daniel Sauter
- Institute of Molecular Virology, Ulm University Medical Center, 89081 Ulm, Germany.
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Douglas JL, Bai Y, Gustin JK, Moses AV. A comparative mutational analysis of HIV-1 Vpu subtypes B and C for the identification of determinants required to counteract BST-2/Tetherin and enhance viral egress. Virology 2013; 441:182-96. [PMID: 23582304 PMCID: PMC3760674 DOI: 10.1016/j.virol.2013.03.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Revised: 02/26/2013] [Accepted: 03/18/2013] [Indexed: 12/28/2022]
Abstract
We have undertaken a genetic strategy to map Vpu regions necessary for BST-2 antagonism and viral egress. This approach is based on our identification of an egress-defective Vpu variant encoded by an HIV-1 subtype C strain. We constructed a series of chimeric Vpu molecules made from the Vpu C variant and Vpu B from a standard laboratory strain. The TM domain from the inactive Vpu C, which contains multiple non-conserved residues, was responsible for a significant decrease in egress activity and BST-2 downregulation, confirming the functional importance of the Vpu TM domain. However, for complete inactivation, both the N-terminus and TM domain from the inactive Vpu C molecule were required, suggesting a new role for the Vpu N-terminus. In addition, determinants in the C-terminus of Vpu B that may be involved in efficient TGN accumulation were also necessary for enhanced viral egress but are missing or non-functional in Vpu C.
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Affiliation(s)
- Janet L. Douglas
- Vaccine and Gene Therapy Institute, Oregon Health & Science University, 505 NW 185th Ave, Beaverton, OR 97006, United States
| | - Ying Bai
- Vaccine and Gene Therapy Institute, Oregon Health & Science University, 505 NW 185th Ave, Beaverton, OR 97006, United States
| | - Jean K. Gustin
- Vaccine and Gene Therapy Institute, Oregon Health & Science University, 505 NW 185th Ave, Beaverton, OR 97006, United States
| | - Ashlee V. Moses
- Vaccine and Gene Therapy Institute, Oregon Health & Science University, 505 NW 185th Ave, Beaverton, OR 97006, United States
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Sandberg JK, Andersson SK, Bächle SM, Nixon DF, Moll M. HIV-1 Vpu interference with innate cell-mediated immune mechanisms. Curr HIV Res 2013; 10:327-33. [PMID: 22524181 PMCID: PMC3412205 DOI: 10.2174/157016212800792513] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2012] [Revised: 03/06/2012] [Accepted: 03/14/2012] [Indexed: 12/26/2022]
Abstract
The HIV-1 accessory protein Vpu is emerging as a viral factor with a range of activities devoted to counteracting host innate immunity. Here, we review recent findings concerning the role of Vpu in hampering activation of cellular immune responses mediated by CD1d-restricted invariant natural killer T (iNKT) cells and natural killer (NK) cells. The two key findings are that Vpu interferes with CD1d expression and antigen presentation, and also with expression of the NK cell activation ligand NK-T and B cell antigen (NTB-A). Both these activities are mechanistically distinct from CD4 and Tetherin (BST-2) down-modulation. We summarize the mechanistic insights gained into Vpu interference with CD1d and NTB-A, as well as important challenges going forward, and discuss these mechanisms in the context of the role that iNKT and NK cells play in HIV-1 immunity and immunopathogenesis.
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Affiliation(s)
- Johan K Sandberg
- Center for Infectious Medicine, Department of Medicine, Karolinska Institutet, Karolinska University Hospital Huddinge, Stockholm, Sweden.
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Kluge SF, Sauter D, Vogl M, Peeters M, Li Y, Bibollet-Ruche F, Hahn BH, Kirchhoff F. The transmembrane domain of HIV-1 Vpu is sufficient to confer anti-tetherin activity to SIVcpz and SIVgor Vpu proteins: cytoplasmic determinants of Vpu function. Retrovirology 2013; 10:32. [PMID: 23514615 PMCID: PMC3621411 DOI: 10.1186/1742-4690-10-32] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2013] [Accepted: 03/08/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The acquisition of effective Vpu-mediated anti-tetherin activity to promote virion release following transmission of SIVcpzPtt from central chimpanzees (Pan troglodytes troglodytes) to humans distinguishes pandemic HIV-1 group M strains from non-pandemic group N, O and P viruses and may have been a prerequisite for their global spread. Some functional motifs in the cytoplasmic region of HIV-1 M Vpus proposed to be important for anti-tetherin activity are more frequently found in the Vpu proteins of SIVcpzPtt than in those of SIVcpzPts infecting eastern chimpanzees (P. t. schweinfurthii), that have not been detected in humans, and SIVgor from gorillas, which is closely related to HIV-1 O and P. Thus, SIVcpzPtt strains may require fewer adaptive changes in Vpu than SIVcpzPts or SIVgor strains to counteract human tetherin. RESULTS To examine whether SIVcpzPtt may only need changes in the transmembrane domain (TMD) of Vpu to acquire anti-tetherin activity, whereas SIVcpzPts and SIVgor may also require changes in the cytoplasmic region, we analyzed chimeras between the TMD of an HIV-1 M Vpu and the cytoplasmic domains of SIVcpzPtt (n = 2), SIVcpzPts (n = 2) and SIVgor (n = 2) Vpu proteins. Unexpectedly, all of these chimeras were capable of counteracting human tetherin to enhance virion release, irrespective of the presence or absence of the putative adaptor protein binding sites and the DSGxxS β-TrCP binding motif reported to be critical for effective anti-tetherin activity of M Vpus. It was also surprising that in three of the six chimeras the gain of anti-tetherin function was associated with a loss of the CD4 degradation activity since this function was conserved among all parental HIV-1, SIVcpz and SIVgor Vpu proteins. CONCLUSIONS Our results show that changes in the TMD of SIVcpzPtt, SIVcpzPts and SIVgor Vpus are sufficient to render them active against human tetherin. Thus, several previously described domains in the extracellular region of Vpu are not absolutely essential for tetherin antagonism but may be required for other Vpu functions.
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Affiliation(s)
- Silvia F Kluge
- Institute of Molecular Virology, Ulm University Medical Center, Ulm, Germany.
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Reacquisition of Nef-mediated tetherin antagonism in a single in vivo passage of HIV-1 through its original chimpanzee host. Cell Host Microbe 2013; 12:373-80. [PMID: 22980333 DOI: 10.1016/j.chom.2012.07.008] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2012] [Revised: 06/11/2012] [Accepted: 07/06/2012] [Indexed: 02/02/2023]
Abstract
The interferon-induced host restriction factor tetherin poses a barrier for SIV transmission from primates to humans. After cross-species transmission, the chimpanzee precursor of pandemic HIV-1 switched from the accessory protein Nef to Vpu to effectively counteract human tetherin. As we report here, the experimental reintroduction of HIV-1 into its original chimpanzee host resulted in a virus that can use both Vpu and Nef to antagonize chimpanzee tetherin. Functional analyses demonstrated that alterations in and near the highly conserved ExxxLL motif in the C-terminal loop of Nef were critical for the reacquisition of antitetherin activity. Strikingly, just two amino acid changes allowed HIV-1 Nef to counteract chimpanzee tetherin and promote virus release. Our data demonstrate that primate lentiviruses can reacquire lost accessory gene functions during a single in vivo passage and suggest that other functional constraints keep Nef ready to regain antitetherin activity.
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Abstract
Tetherin (BST2/CD317) has emerged as a key host cell defense molecule, inhibiting the release and spread of diverse enveloped virions from infected cells. In this chapter, I review the molecular and cellular basis for tetherin's antiviral activities and the function of virally encoded countermeasures that disrupt its function. I further describe recent advances in our understanding of tetherin's associated role in viral pattern recognition and the evidence for its role in limiting viral pathogenesis in vivo.
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Affiliation(s)
- Stuart J D Neil
- Department of Infectious Disease, King's College London School of Medicine, London, UK.
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Human tetherin exerts strong selection pressure on the HIV-1 group N Vpu protein. PLoS Pathog 2012; 8:e1003093. [PMID: 23308067 PMCID: PMC3534379 DOI: 10.1371/journal.ppat.1003093] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2012] [Accepted: 10/30/2012] [Indexed: 12/19/2022] Open
Abstract
HIV-1 groups M and N emerged within the last century following two independent cross-species transmissions of SIVcpz from chimpanzees to humans. In contrast to pandemic group M strains, HIV-1 group N viruses are exceedingly rare, with only about a dozen infections identified, all but one in individuals from Cameroon. Poor adaptation to the human host may be responsible for this limited spread of HIV-1 group N in the human population. Here, we analyzed the function of Vpu proteins from seven group N strains from Cameroon, the place where this zoonosis originally emerged. We found that these N-Vpus acquired four amino acid substitutions (E15A, V19A and IV25/26LL) in their transmembrane domain (TMD) that allow efficient interaction with human tetherin. However, despite these adaptive changes, most N-Vpus still antagonize human tetherin only poorly and fail to down-modulate CD4, the natural killer (NK) cell ligand NTB-A as well as the lipid-antigen presenting protein CD1d. These functional deficiencies were mapped to amino acid changes in the cytoplasmic domain that disrupt putative adaptor protein binding sites and an otherwise highly conserved ßTrCP-binding DSGxxS motif. As a consequence, N-Vpus exhibited aberrant intracellular localization and/or failed to recruit the ubiquitin-ligase complex to induce tetherin degradation. The only exception was the Vpu of a group N strain recently discovered in France, but originally acquired in Togo, which contained intact cytoplasmic motifs and counteracted tetherin as effectively as the Vpus of pandemic HIV-1 M strains. These results indicate that HIV-1 group N Vpu is under strong host-specific selection pressure and that the acquisition of effective tetherin antagonism may lead to the emergence of viral variants with increased transmission fitness. Differences in their degree of adaptation to humans may explain why only one of four ape-derived SIV zoonoses spawned the AIDS pandemic. Specifically, only HIV-1 strains of the pandemic M group evolved a fully functional Vpu that efficiently antagonizes human tetherin and degrades CD4. In comparison, the rare group N viruses gained some anti-tetherin activity but lost the CD4 degradation function. Here, we show that the N-Vpu transmembrane domain has adapted to interact with human tetherin and identified the mutations that enable this interaction. However, we also show that most N-Vpus remain poor tetherin antagonists and fail to reduce the surface expression of CD4, the natural killer cell ligand NTB-A and the lipid-antigen presenting protein CD1d. This is due to mutations in their cytoplasmic region that are associated with aberrant protein localization and impaired interaction with the ubiquitin/proteasome pathway. A remarkable exception is the Vpu of the first HIV-1 N strain known to be transmitted outside of Cameroon, which contains a functional cytoplasmic domain and is a highly effective tetherin antagonist. These data indicate that group N viruses are still adapting to humans and that the acquisition of potent anti-tetherin activity may eventually lead to the emergence of viral variants that exhibit increased transmission fitness.
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De Candia C, Espada C, Duette G, Salomón H, Carobene M. Human immunodeficiency virus-1 BF intersubtype recombinant viral protein U second α helix plays an important role in viral release and BST-2 degradation. J Gen Virol 2012; 94:758-766. [PMID: 23223624 DOI: 10.1099/vir.0.047746-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
We previously reported a naturally occurring BF intersubtype recombinant viral protein U (Vpu) variant with an augmented capacity to enhance viral replication. Structural analysis of this variant revealed that its transmembrane domain and α-helix I in the cytoplasmic domain (CTD) corresponded to subtype B, whereas the α-helix II in the CTD corresponded to subtype F1. In this study, we aimed to evaluate the role of the Vpu cytoplasmic α-helix II domain in viral release enhancement and in the down-modulation of BST-2 and CD4 from the cell surface. In addition, as serine residues in Vpu amino acid positions 61 or 64 have been shown to regulate Vpu intracellular half-life, which in turn could influence the magnitude of viral release, we also studied the impact of these residues on the VpuBF functions, since S61 and S64 are infrequently found among BF recombinant Vpu variants. Our results showed that the exchange of Vpu α-helix II between subtypes (B→F) directly correlated with the enhancement of viral release and, to a lesser extent, with changes in the capacity of the resulting chimera to down-modulate BST-2 and CD4. No differences in viral release and BST-2 down-modulation were observed between VpuBF and VpuBF-E61S. On the other hand, VpuBF-A64S showed a slightly reduced capacity to enhance viral production, but was modestly more efficient than VpuBF in down-modulating BST-2. In summary, our observations clearly indicate that α-helix II is actively involved in Vpu viral-release-promoting activity and that intersubtype recombination between subtypes B and F1 created a protein variant with a higher potential to boost the spread of the recombinant strain that harbours it.
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Affiliation(s)
- Cristian De Candia
- Instituto de Investigaciones Biomédicas en Retrovirus y SIDA (INBIRS), Universidad de Buenos Aires, Paraguay 2155 Piso11, C1121AGB Buenos Aires, Argentina
| | - Constanza Espada
- Instituto de Investigaciones Biomédicas en Retrovirus y SIDA (INBIRS), Universidad de Buenos Aires, Paraguay 2155 Piso11, C1121AGB Buenos Aires, Argentina
| | - Gabriel Duette
- Instituto de Investigaciones Biomédicas en Retrovirus y SIDA (INBIRS), Universidad de Buenos Aires, Paraguay 2155 Piso11, C1121AGB Buenos Aires, Argentina
| | - Horacio Salomón
- Instituto de Investigaciones Biomédicas en Retrovirus y SIDA (INBIRS), Universidad de Buenos Aires, Paraguay 2155 Piso11, C1121AGB Buenos Aires, Argentina
| | - Mauricio Carobene
- Instituto de Investigaciones Biomédicas en Retrovirus y SIDA (INBIRS), Universidad de Buenos Aires, Paraguay 2155 Piso11, C1121AGB Buenos Aires, Argentina
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Ruiz A, Schmitt K, Culley N, Stephens EB. Simian-Human immunodeficiency viruses expressing chimeric subtype B/C Vpu proteins demonstrate the importance of the amino terminal and transmembrane domains in the rate of CD4(+) T cell loss in macaques. Virology 2012; 435:395-405. [PMID: 23218949 DOI: 10.1016/j.virol.2012.10.030] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2012] [Revised: 08/20/2012] [Accepted: 10/20/2012] [Indexed: 10/27/2022]
Abstract
Previously, we reported that simian-human immunodeficiency viruses expressing either the lab adapted subtype B (SHIV(KU-1bMC33)) or subtype C (SHIV(SCVpu)) Vpu proteins of human immunodeficiency virus type 1 (HIV-1) had different rates of CD4(+) T cell loss following inoculation into macaques. In this study, we have generated SHIVs that express either the subtype B or subtype C N-terminal (NTD) and transmembrane (TMD) domains and the opposing cytoplasmic domain (SHIV(VpuBC), SHIV(VpuCB)). In culture systems, SHIV(VpuBC) replicated faster than SHIV(VpuCB) while both proteins exhibited similar ability to down-modulate CD4 surface expression. Following inoculation into macaques, SHIV(VpuBC) resulted in rapid CD4(+) T cell loss similar to the parental SHIV(KU-1bMC33), while the rate of CD4(+) T cell loss in those inoculated with SHIV(VpuCB) was intermediate of SHIV(SCVpu) and SHIV(KU-1bMC33). These results emphasize the importance of the Vpu NTD/TMD region in the rate of CD4(+) T cell loss in the pathogenic X4 SHIV/macaque model.
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Affiliation(s)
- Autumn Ruiz
- Department of Microbiology, Molecular Genetics, and Immunology, University of Kansas Medical Center, Kansas City, KS 66160, USA
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Jeang KT. Highlights, predictions, and changes. Retrovirology 2012; 9:96. [PMID: 23153244 PMCID: PMC3511057 DOI: 10.1186/1742-4690-9-96] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2012] [Accepted: 11/08/2012] [Indexed: 11/10/2022] Open
Abstract
Recent literature highlights at Retrovirology are described. Predictions are made regarding "hot" retrovirology research trends for the coming year based on recent journal access statistics. Changes in Retrovirology editor and the frequency of the Retrovirology Prize are announced.
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