1
|
Moisan A, Tombette F, Vautrin M, Alessandri-Gradt E, Mourez T, Plantier JC. In vitro replicative potential of an HIV-1/MO intergroup recombinant virus compared to HIV-1/M and HIV-1/O parental viruses. Sci Rep 2024; 14:1730. [PMID: 38242913 PMCID: PMC10799055 DOI: 10.1038/s41598-024-51873-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Accepted: 01/10/2024] [Indexed: 01/21/2024] Open
Abstract
Genetic recombination is one of the major evolution processes of HIV-1. Despite their great genetic divergence, HIV-1 groups M and O can generate HIV-1/MO intergroup recombinants. The current description of 20 HIV-1/MO unique recombinant forms suggests a possible benefit of the recombination. The aim of this work was to study in vitro the replicative potential of HIV-1/MO recombinant forms. This analysis was based on a simple recombination pattern, [Ogag/pol-Menv], harboring a breakpoint in Vpr. A chimeric infectious molecular clone, pOM-TB-2016 was synthesized from HIV-1/M subtype B and HIV-1/O subgroup T and recombinant viruses were obtained by transfection/co-culture. To compare the replicative potential of these viruses, two markers were monitored in culture supernatants: Reverse Transcriptase (RT) activity and P24 antigen concentration. The results showed a superiority of the group M parental virus compared to group O for both markers. In contrast, for the recombinant virus, RT activity data did not overlap with the concentration of P24 antigen, suggesting a hybrid behavior of the recombinant, in terms of enzyme activity and P24 production. These results highlighted many hypotheses about the impact of recombination on replicative potential and demonstrated again the significant plasticity of HIV genomes and their infinite possibility of evolution.
Collapse
Affiliation(s)
- Alice Moisan
- Univ Rouen Normandie, Université de Caen Normandie, INSERM, Normandie Univ, DYNAMICURE UMR 1311, CHU Rouen, Department of Virology, National Reference Center of HIV, 76000, Rouen, France.
| | - Fabienne Tombette
- Univ Rouen Normandie, Université de Caen Normandie, INSERM, Normandie Univ, DYNAMICURE UMR 1311, CHU Rouen, Department of Virology, National Reference Center of HIV, 76000, Rouen, France
| | - Manon Vautrin
- Univ Rouen Normandie, Université de Caen Normandie, INSERM, Normandie Univ, DYNAMICURE UMR 1311, 76000, Rouen, France
| | - Elodie Alessandri-Gradt
- Univ Rouen Normandie, Université de Caen Normandie, INSERM, Normandie Univ, DYNAMICURE UMR 1311, CHU Rouen, Department of Virology, National Reference Center of HIV, 76000, Rouen, France
| | - Thomas Mourez
- Univ Rouen Normandie, Université de Caen Normandie, INSERM, Normandie Univ, DYNAMICURE UMR 1311, CHU Rouen, Department of Virology, National Reference Center of HIV, 76000, Rouen, France
| | - Jean-Christophe Plantier
- Univ Rouen Normandie, Université de Caen Normandie, INSERM, Normandie Univ, DYNAMICURE UMR 1311, CHU Rouen, Department of Virology, National Reference Center of HIV, 76000, Rouen, France.
| |
Collapse
|
2
|
Volcic M, Wiesmüller L, Kirchhoff F. Small but Highly Versatile: The Viral Accessory Protein Vpu. Annu Rev Virol 2023; 10:243-259. [PMID: 37406340 DOI: 10.1146/annurev-virology-111821-100816] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/07/2023]
Abstract
Human and simian immunodeficiency viruses (HIVs and SIVs, respectively) encode several small proteins (Vif, Vpr, Nef, Vpu, and Vpx) that are called accessory because they are not generally required for viral replication in cell culture. However, they play complex and important roles for viral immune evasion and spread in vivo. Here, we discuss the diverse functions and the relevance of the viral protein U (Vpu) that is expressed from a bicistronic RNA during the late stage of the viral replication cycle and found only in HIV-1 and closely related SIVs. It is well established that Vpu counteracts the restriction factor tetherin, mediates degradation of the primary viral CD4 receptors, and inhibits activation of the transcription factor nuclear factor kappa B. Recent studies identified additional activities and provided new insights into the sophisticated mechanisms by which Vpu enhances and prolongs the release of fully infectious viral particles. In addition, it has been shown that Vpu prevents superinfection not only by degrading CD4 but also by modulating DNA repair mechanisms to promote degradation of nuclear viral complementary DNA in cells that are already productively infected.
Collapse
Affiliation(s)
- Meta Volcic
- Institute of Molecular Virology, Ulm University Medical Center, Ulm, Germany;
| | - Lisa Wiesmüller
- Division of Gynecological Oncology, Department of Obstetrics and Gynecology, Ulm University Medical Center, Ulm, Germany
| | - Frank Kirchhoff
- Institute of Molecular Virology, Ulm University Medical Center, Ulm, Germany;
| |
Collapse
|
3
|
Nef Suppresses LINE-1 Retrotransposition through Two Distinct Mechanisms. J Virol 2022; 96:e0114822. [PMID: 36197106 DOI: 10.1128/jvi.01148-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Long interspersed element type 1 (LINE-1) is the only known type of retroelement that can replicate autonomously, and its retrotransposition activity can trigger interferon (IFN) production. IFN production suppresses the infectivity of exogenous viruses, such as human immunodeficiency virus (HIV). As a counteraction, HIV has been reported to use multiple proteins and mechanisms to suppress LINE-1 replication. However, the mechanisms of HIV-mediated LINE-1 regulation are not fully understood. In this study, we discovered that Nef protein, which is expressed by HIV and is important for HIV pathogenesis, inhibits LINE-1 retrotransposition. Two distinct mechanisms have been uncovered for Nef-induced LINE-1 suppression. Without direct interaction with LINE-1 DNA, Nef potently inhibits the promoter activity of the LINE-1 5'-untranslated region (5'-UTR) and reduces the expression levels of LINE-1 RNA and proteins. Alternatively, although Nef does not bind to the LINE-1 open reading frame 1 protein (ORF1p) or LINE-1 RNA, it significantly compromises the ORF1p-LINE-1 RNA interaction, which is essential for LINE-1 retrotransposition. Both mechanisms can be suppressed by the G2A mutation, which abolishes myristoylation of Nef, suggesting that membrane attachment is essential for Nef to suppress LINE-1. Consequently, through LINE-1 inhibition, Nef downregulates IFN production in host cells. Therefore, our data revealed that Nef is a potent LINE-1 suppressor and an effective innate immune regulator, which not only provides new information on the intricate interaction between HIV, LINE-1, and IFN signaling systems but also strengthens the importance of Nef in HIV infection and highlights the potential of designing novel Nef-targeting anti-HIV drugs. IMPORTANCE Human immunodeficiency viruses are pathogens of AIDS that were first discovered almost 40 years ago and continue to threaten human lives to date. While currently used anti-HIV drugs are sufficient to suppress viral loads in HIV-infected patients, both drug-resistant HIV strains and adverse side effects triggered by the long-term use of these drugs highlight the need to develop novel anti-HIV drugs targeting different viral proteins and/or different steps in viral replication. To achieve this, more information is required regarding HIV pathogenesis and especially its impact on cellular activities in host cells. In this study, we discovered that the Nef protein expressed by HIV potently inhibits LINE-1 retrotransposition. During our attempt to determine the mechanism of Nef-mediated LINE-1 suppression, two additional functions of Nef were uncovered. Nef effectively repressed the promoter activity of LINE-1 5'-UTR and destabilized the interaction between ORF1p and LINE-1 RNA. Consequently, Nef not only compromises LINE-1 replication but also reduces LINE-1-triggered IFN production. The reduction in IFN production, in theory, promotes HIV infectivity. Together with its previously known functions, these findings indicate that Nef is a potential target for the development of novel anti-HIV drugs. Notably, the G2 residue, which has been reported to be essential for most Nef functions, was found to be critical in the regulation of innate immune activation by Nef, suggesting that compromising myristoylation or membrane attachment of Nef may be a good strategy for the inhibition of HIV infection.
Collapse
|
4
|
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.
Collapse
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:
| |
Collapse
|
5
|
Sousa JD, Havik PJ, Müller V, Vandamme AM. Newly Discovered Archival Data Show Coincidence of a Peak of Sexually Transmitted Diseases with the Early Epicenter of Pandemic HIV-1. Viruses 2021; 13:v13091701. [PMID: 34578283 PMCID: PMC8472979 DOI: 10.3390/v13091701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 08/17/2021] [Accepted: 08/19/2021] [Indexed: 11/24/2022] Open
Abstract
To which extent STDs facilitated HIV-1 adaptation to humans, sparking the pandemic, is still unknown. We searched colonial medical records from 1906–1958 for Leopoldville, Belgian Congo, which was the initial epicenter of pandemic HIV-1, compiling counts of treated STD cases in both Africans and Europeans. Almost all Europeans were being treated, while for Africans, generalized treatment started only in 1929. Treated STD counts in Europeans thus reflect STD infection rates more accurately compared to counts in Africans. In Africans, the highest recorded STD treatment incidence was in 1929–1935, declining to low levels in the 1950s. In Europeans, the recorded treatment incidences were highest during the period 1910–1920, far exceeding those in Africans. Europeans were overwhelmingly male and had frequent sexual contact with African females. Consequently, high STD incidence among Europeans must have coincided with high prevalence and incidence in the city’s African population. The data strongly suggest the worst STD period was 1910–1920 for both Africans and Europeans, which coincides with the estimated origin of pandemic HIV-1. Given the strong effect of STD coinfections on HIV transmission, these new data support our hypothesis of a causal effect of STDs on the epidemic emergence of HIV-1.
Collapse
Affiliation(s)
- João Dinis Sousa
- Clinical and Epidemiological Virology, Rega Institute for Medical Research, Department of Microbiology, Immunology and Transplantation, KU Leuven, B-3000 Leuven, Belgium;
- Global Health and Tropical Medicine, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, 1349-008 Lisbon, Portugal;
- Correspondence:
| | - Philip J. Havik
- Global Health and Tropical Medicine, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, 1349-008 Lisbon, Portugal;
| | - Viktor Müller
- Institute of Biology, Eötvös Loránd University, 1117 Budapest, Hungary;
| | - Anne-Mieke Vandamme
- Clinical and Epidemiological Virology, Rega Institute for Medical Research, Department of Microbiology, Immunology and Transplantation, KU Leuven, B-3000 Leuven, Belgium;
- Global Health and Tropical Medicine, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, 1349-008 Lisbon, Portugal;
- Institute for the Future, KU Leuven, B-3000 Leuven, Belgium
| |
Collapse
|
6
|
Nakano Y, Yamamoto K, Ueda MT, Soper A, Konno Y, Kimura I, Uriu K, Kumata R, Aso H, Misawa N, Nagaoka S, Shimizu S, Mitsumune K, Kosugi Y, Juarez-Fernandez G, Ito J, Nakagawa S, Ikeda T, Koyanagi Y, Harris RS, Sato K. A role for gorilla APOBEC3G in shaping lentivirus evolution including transmission to humans. PLoS Pathog 2020; 16:e1008812. [PMID: 32913367 PMCID: PMC7482973 DOI: 10.1371/journal.ppat.1008812] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Accepted: 07/15/2020] [Indexed: 12/12/2022] Open
Abstract
The APOBEC3 deaminases are potent inhibitors of virus replication and barriers to cross-species transmission. For simian immunodeficiency virus (SIV) to transmit to a new primate host, as happened multiple times to seed the ongoing HIV-1 epidemic, the viral infectivity factor (Vif) must be capable of neutralizing the APOBEC3 enzymes of the new host. Although much is known about current interactions of HIV-1 Vif and human APOBEC3s, the evolutionary changes in SIV Vif required for transmission from chimpanzees to gorillas and ultimately to humans are poorly understood. Here, we demonstrate that gorilla APOBEC3G is a factor with the potential to hamper SIV transmission from chimpanzees to gorillas. Gain-of-function experiments using SIVcpzPtt Vif revealed that this barrier could be overcome by a single Vif acidic amino acid substitution (M16E). Moreover, degradation of gorilla APOBEC3F is induced by Vif through a mechanism that is distinct from that of human APOBEC3F. Thus, our findings identify virus adaptations in gorillas that preceded and may have facilitated transmission to humans. Humans are exposed continuously to a menace of viral diseases such as Ebola virus and coronaviruses. Such emerging/re-emerging viral outbreaks can be triggered by cross-species viral transmission from wild animals to humans. HIV-1, the causative agent of AIDS, most likely originated from related precursors found in chimpanzees and gorillas (SIVcpzPtt or SIVgor), approximately 100 years ago. Additionally, SIVgor most likely emerged through the cross-species jump of SIVcpzPtt from chimpanzees to gorillas. However, it remains unclear how primate lentiviruses successfully transmitted among different species. To limit cross-species lentiviral transmission, cellular "restriction factors", including tetherin, SAMHD1, and APOBEC3 proteins potentially inhibit lentiviral replication. In contrast, primate lentiviruses have evolutionary acquired their own "arms" to antagonize the antiviral effect of restriction factors. Here we show that gorilla APOBEC3G potentially plays a role in inhibiting SIVcpzPtt replication. To our knowledge, this is the first report suggesting that a great ape APOBEC3 protein can potentially restrict the cross-species transmission of great ape lentiviruses and how lentiviruses overcame this species barrier.
Collapse
Affiliation(s)
- Yusuke Nakano
- Laboratory of Systems Virology, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
| | - Keisuke Yamamoto
- Laboratory of Systems Virology, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
- Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Mahoko Takahashi Ueda
- Department of Molecular Life Science, Tokai University School of Medicine, Kanagawa, Japan
| | - Andrew Soper
- Laboratory of Systems Virology, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
- Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Yoriyuki Konno
- Laboratory of Systems Virology, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
- 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
- Graduate School of Biostudies, Kyoto University, Kyoto, Japan
| | - Izumi Kimura
- Laboratory of Systems Virology, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
- 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
- Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
| | - Keiya Uriu
- 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
- Graduate School of Medicine, the University of Tokyo, Tokyo, Japan
| | - Ryuichi Kumata
- Laboratory of Systems Virology, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
- 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
- Faculty of Science, Kyoto University, Kyoto, Japan
| | - Hirofumi Aso
- Laboratory of Systems Virology, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
- 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
- Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
| | - Naoko Misawa
- Laboratory of Systems Virology, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
| | - Shumpei Nagaoka
- Laboratory of Systems Virology, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
- 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
- Graduate School of Biostudies, Kyoto University, Kyoto, Japan
| | - Soma Shimizu
- Laboratory of Systems Virology, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
- Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
| | - Keito Mitsumune
- Laboratory of Systems Virology, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
- Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
| | - Yusuke Kosugi
- Laboratory of Systems Virology, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
- Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
| | - Guillermo Juarez-Fernandez
- Laboratory of Systems Virology, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
- Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Jumpei Ito
- Laboratory of Systems Virology, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
- 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
| | - So Nakagawa
- Department of Molecular Life Science, Tokai University School of Medicine, Kanagawa, Japan
| | - Terumasa Ikeda
- Department of Biochemistry, Molecular Biology and Biophysics, Masonic Cancer Center, Institute for Molecular Virology, Center for Genome Engineering, University of Minnesota, Minneapolis, Minnesota, United States of America
- Howard Hughes Medical Institute, University of Minnesota, Minneapolis, Minnesota, United States of America
- Division of Molecular Virology and Genetics, Joint Research Center for Human Retrovirus Infection, Kumamoto University, Kumamoto, Japan
| | - Yoshio Koyanagi
- Laboratory of Systems Virology, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
- Graduate School of Medicine, Kyoto University, Kyoto, Japan
- Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
| | - Reuben S. Harris
- Department of Biochemistry, Molecular Biology and Biophysics, Masonic Cancer Center, Institute for Molecular Virology, Center for Genome Engineering, University of Minnesota, Minneapolis, Minnesota, United States of America
- Howard Hughes Medical Institute, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Kei Sato
- Laboratory of Systems Virology, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
- 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
- Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
- Graduate School of Medicine, the University of Tokyo, Tokyo, Japan
- CREST, Japan Science and Technology Agency, Saitama, Japan
- * E-mail:
| |
Collapse
|
7
|
Schouest B, Leslie GJ, Hoxie JA, Maness NJ. Tetherin downmodulation by SIVmac Nef lost with the H196Q escape variant is restored by an upstream variant. PLoS One 2020; 15:e0225420. [PMID: 32764749 PMCID: PMC7413475 DOI: 10.1371/journal.pone.0225420] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Accepted: 07/13/2020] [Indexed: 01/17/2023] Open
Abstract
The H196 residue in SIVmac239 Nef is conserved across the majority of HIV and SIV isolates, lies immediately adjacent to the AP-2 (adaptor protein 2) binding di-leucine domain (ExxxLM195), and is critical for several described AP-2 dependent Nef functions, including the downregulation of tetherin (BST-2/CD317), CD4, and others. Surprisingly, many stocks of the closely related SIVmac251 swarm virus harbor a nef allele encoding a Q196. In SIVmac239, this variant is associated with loss of multiple AP-2 dependent functions. Publicly available sequences for SIVmac251 stocks were mined for variants linked to Q196 that might compensate for functional defects associated with this residue. Variants were engineered into the SIVmac239 backbone and in Nef expression plasmids and flow cytometry was used to examine surface tetherin expression in primary CD4 T cells and surface CD4 expression in SupT1 cells engineered to express rhesus CD4. We found that SIVmac251 stocks that encode a Q196 residue in Nef uniformly also encode an upstream R191 residue. We show that R191 restores the ability of Nef to downregulate tetherin in the presence of Q196 and has a similar but less pronounced impact on CD4 expression. However, a published report showed Q196 commonly evolves to H196 in vivo, suggesting a fitness cost. R191 may represent compensatory evolution to restore the ability to downregulate tetherin lost in viruses harboring Q196.
Collapse
Affiliation(s)
- Blake Schouest
- Division of Microbiology, Tulane National Primate Research Center, Covington, LA, United States of America
| | - George J. Leslie
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States of America
| | - James A. Hoxie
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States of America
| | - Nicholas J. Maness
- Division of Microbiology, Tulane National Primate Research Center, Covington, LA, United States of America
- Department of Microbiology and Immunology, School of Medicine, Tulane University Health Sciences Center, New Orleans, LA, United States of America
- * E-mail:
| |
Collapse
|
8
|
Giese S, Lawrence SP, Mazzon M, Nijmeijer BM, Marsh M. The Nef Protein of the Macrophage Tropic HIV-1 Strain AD8 Counteracts Human BST-2/Tetherin. Viruses 2020; 12:E459. [PMID: 32325729 PMCID: PMC7232323 DOI: 10.3390/v12040459] [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: 02/10/2020] [Revised: 04/15/2020] [Accepted: 04/15/2020] [Indexed: 12/12/2022] Open
Abstract
Bone Marrow Stromal Cell Antigen 2 (BST-2)/tetherin inhibits the release of numerous enveloped viruses by physically tethering nascent particles to infected cells during the process of viral budding from the cell surface. Tetherin also restricts human immunodeficiency virus (HIV), and pandemic main (M) group HIV type 1s (HIV-1s) are thought to rely exclusively on their Vpu proteins to overcome tetherin-mediated restriction of virus release. However, at least one M group HIV-1 strain, the macrophage-tropic primary AD8 isolate, is unable to express Vpu due to a mutation in its translation initiation codon. Here, using primary monocyte-derived macrophages (MDMs), we show that AD8 Nef protein can compensate for the absence of Vpu and restore virus release to wild type levels. We demonstrate that HIV-1 AD8 Nef reduces endogenous cell surface tetherin levels, physically separating it from the site of viral budding, thus preventing HIV retention. Mechanistically, AD8 Nef enhances internalisation of the long isoform of human tetherin, leading to perinuclear accumulation of the restriction factor. Finally, we show that Nef proteins from other HIV strains also display varying degrees of tetherin antagonism. Overall, we show that M group HIV-1s can use an accessory protein other than Vpu to antagonise human tetherin.
Collapse
Affiliation(s)
| | | | | | | | - Mark Marsh
- MRC Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, UK; (S.G.); (S.P.L.); (M.M.); (B.M.N.)
| |
Collapse
|
9
|
In vitro replicative fitness of early Transmitted founder HIV-1 variants and sensitivity to Interferon alpha. Sci Rep 2020; 10:2747. [PMID: 32066770 PMCID: PMC7026412 DOI: 10.1038/s41598-020-59596-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Accepted: 01/14/2020] [Indexed: 01/10/2023] Open
Abstract
Type I interferons, particularly interferon-alpha (IFN-α), play a vital role in the host's anti-viral defenses by interfering with viral replication. However, the virus rapidly evolves to exploit the IFN-α response for its replication, spread, and pathogenic function. In this study, we attempted to determine IFN-α susceptibility and productivity of infectious transmitted/founder (TF) (n = 8) and non-transmitted (NT) viruses (n = 8) derived from HIV-1 infected infants. Independent experiments were carried out to determine IFN-α resistance, replication fitness, and viral productivity in CD4+ T cells over a short period. In vitro studies showed that TF viruses were resistant to IFN-α during the very near moment of transmission, but in the subsequent time points, they became susceptible to IFN-α. We did not observe much difference in replicative fitness of the TF viruses in cultures treated with and without IFN-α, but the difference was significant in the case of NT viruses obtained from the same individual. Despite increased susceptibility to IFN-α, NT viruses produced more viral particles than TF viruses. Similar results were also obtained in cultures treated with maraviroc (MVC). The study identified unique characteristics of TF viruses thus prompting further investigation into virus-host interaction occurring during the early stages of HIV infection.
Collapse
|
10
|
Multifunctional Roles of the N-Terminal Region of HIV-1 SF2Nef Are Mediated by Three Independent Protein Interaction Sites. J Virol 2019; 94:JVI.01398-19. [PMID: 31597760 DOI: 10.1128/jvi.01398-19] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Accepted: 10/01/2019] [Indexed: 01/23/2023] Open
Abstract
HIV-1 Nef promotes virus spread and disease progression by altering host cell transport and signaling processes through interaction with multiple host cell proteins. The N-terminal region in HIV-1 Nef encompassing residues 12 to 39 has been implicated in many Nef activities, including disruption of CD4 T lymphocyte polarization and homing to lymph nodes, antagonism of SERINC5 restriction to virion infectivity, downregulation of cell surface CD4 and major histocompatibility complex class I (MHC-I), release of Nef-containing extracellular vesicles, and phosphorylation of Nef by recruitment of the Nef-associated kinase complex (NAKC). How this region mediates these pleiotropic functions is unclear. Characterization of a panel of alanine mutants spanning the N-terminal region to identify specific functional determinants revealed this region to be dispensable for effects of Nef from HIV-1 strain SF2 (HIV-1SF2Nef) on T cell actin organization and chemotaxis, retargeting of the host cell kinase Lck to the trans-Golgi network, and incorporation of Nef into extracellular vesicles. MHC-I downmodulation was specific to residue M20, and inhibition of T cell polarization by Nef required the integrity of the entire region. In contrast, downmodulation of cell surface CD4 and SERINC5 antagonism were mediated by a specific motif encompassing residues 32 to 39 that was also essential for efficient HIV replication in primary CD4 T lymphocytes. Finally, Nef phosphorylation via association with the NAKC was mediated by two EP repeats within residues 24 to 29 but was dispensable for other functions. These results identify the N-terminal region as a multifunctional interaction module for at least three different host cell ligands that mediate independent functions of HIV-1SF2Nef to facilitate immune evasion and virus spread.IMPORTANCE HIV-1 Nef critically determines virus spread and disease progression in infected individuals by acting as a protein interaction adaptor via incompletely defined mechanisms and ligands. Residues 12 to 39 near the N terminus of Nef have been described as an interaction platform for the Nef-associated kinase complex (NAKC) and were recently identified as essential determinants for a broad range of Nef activities. Here, we report a systematic mapping of this amino acid stretch that revealed the presence of three independent interaction motifs with specific ligands and activities. While downmodulation of cell surface MHC-I depends on M20, two EP repeats are the minimal binding site for the NAKC, and residues 32 to 39 mediate antagonism of the host cell restriction factor SERINC5 as well as downmodulation of cell surface CD4. These results reveal that the N-terminal region of HIV-1SF2Nef is a versatile and multifunctional protein interaction module that exerts essential functions of the pathogenicity factor via independent mechanisms.
Collapse
|
11
|
Abstract
The accessory protein Nef of human immunodeficiency virus (HIV) is a primary determinant of viral pathogenesis. Nef is abundantly expressed during infection and reroutes a variety of cell surface proteins to disrupt host immunity and promote the viral replication cycle. Nef counteracts host defenses by sequestering and/or degrading its targets via the endocytic and secretory pathways. Nef does this by physically engaging a number of host trafficking proteins. Substantial progress has been achieved in identifying the targets of Nef, and a structural and mechanistic understanding of Nef's ability to command the protein trafficking machinery has recently started to coalesce. Comparative analysis of HIV and simian immunodeficiency virus (SIV) Nef proteins in the context of recent structural advances sheds further light on both viral evolution and the mechanisms whereby trafficking is hijacked. This review describes how advances in cell and structural biology are uncovering in growing detail how Nef subverts the host immune system, facilitates virus release, and enhances viral infectivity.
Collapse
|
12
|
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.
Collapse
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.
| |
Collapse
|
13
|
van Stigt Thans T, Akko JI, Niehrs A, Garcia-Beltran WF, Richert L, Stürzel CM, Ford CT, Li H, Ochsenbauer C, Kappes JC, Hahn BH, Kirchhoff F, Martrus G, Sauter D, Altfeld M, Hölzemer A. Primary HIV-1 Strains Use Nef To Downmodulate HLA-E Surface Expression. J Virol 2019; 93:e00719-19. [PMID: 31375574 PMCID: PMC6798123 DOI: 10.1128/jvi.00719-19] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Accepted: 07/19/2019] [Indexed: 02/08/2023] Open
Abstract
Human immunodeficiency virus type 1 (HIV-1) has evolved elaborate ways to evade immune cell recognition, including downregulation of classical HLA class I (HLA-I) from the surfaces of infected cells. Recent evidence identified HLA-E, a nonclassical HLA-I, as an important part of the antiviral immune response to HIV-1. Changes in HLA-E surface levels and peptide presentation can prompt both CD8+ T-cell and natural killer (NK) cell responses to viral infections. Previous studies reported unchanged or increased HLA-E levels on HIV-1-infected cells. Here, we examined HLA-E surface levels following infection of CD4+ T cells with primary HIV-1 strains and observed that a subset downregulated HLA-E. Two primary strains of HIV-1 that induced the strongest reduction in surface HLA-E expression were chosen for further testing. Expression of single Nef or Vpu proteins in a T-cell line, as well as tail swap experiments exchanging the cytoplasmic tail of HLA-A2 with that of HLA-E, demonstrated that Nef modulated HLA-E surface levels and targeted the cytoplasmic tail of HLA-E. Furthermore, infection of primary CD4+ T cells with HIV-1 mutants showed that a lack of functional Nef (and Vpu to some extent) impaired HLA-E downmodulation. Taken together, the results of this study demonstrate for the first time that HIV-1 can downregulate HLA-E surface levels on infected primary CD4+ T cells, potentially rendering them less vulnerable to CD8+ T-cell recognition but at increased risk of NKG2A+ NK cell killing.IMPORTANCE For almost two decades, it was thought that HIV-1 selectively downregulated the highly expressed HLA-I molecules HLA-A and HLA-B from the cell surface in order to evade cytotoxic-T-cell recognition, while leaving HLA-C and HLA-E molecules unaltered. It was stipulated that HIV-1 infection thereby maintained inhibition of NK cells via inhibitory receptors that bind HLA-C and HLA-E. This concept was recently revised when a study showed that primary HIV-1 strains reduce HLA-C surface levels, whereas the cell line-adapted HIV-1 strain NL4-3 lacks this ability. Here, we demonstrate that infection with distinct primary HIV-1 strains results in significant downregulation of surface HLA-E levels. Given the increasing evidence for HLA-E as an important modulator of CD8+ T-cell and NKG2A+ NK cell functions, this finding has substantial implications for future immunomodulatory approaches aimed at harnessing cytotoxic cellular immunity against HIV.
Collapse
Affiliation(s)
| | - Janet I Akko
- Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany
- German Center for Infection Research (DZIF), Site Hamburg-Lübeck-Borstel-Riems, Germany
| | - Annika Niehrs
- Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany
- German Center for Infection Research (DZIF), Site Hamburg-Lübeck-Borstel-Riems, Germany
| | | | - Laura Richert
- Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany
- Université Bordeaux, Inserm, Bordeaux Population Health Research Center, UMR 1219, Inria SISTM, Bordeaux, France
| | - Christina M Stürzel
- Institute of Molecular Virology, Ulm University Medical Center, Ulm, Germany
| | - Christopher T Ford
- Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany
| | - Hui Li
- Department of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Christina Ochsenbauer
- Department of Medicine, Division of Hematology and Oncology, and CFAR, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - John C Kappes
- Department of Medicine, Division of Hematology and Oncology, and CFAR, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Beatrice H Hahn
- Department of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Frank Kirchhoff
- Institute of Molecular Virology, Ulm University Medical Center, Ulm, Germany
| | - Glòria Martrus
- Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany
| | - Daniel Sauter
- Institute of Molecular Virology, Ulm University Medical Center, Ulm, Germany
| | - Marcus Altfeld
- Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany
- German Center for Infection Research (DZIF), Site Hamburg-Lübeck-Borstel-Riems, Germany
- Institute for Immunology, University Medical Center Eppendorf, Hamburg, Germany
| | - Angelique Hölzemer
- Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany
- German Center for Infection Research (DZIF), Site Hamburg-Lübeck-Borstel-Riems, Germany
- First Department of Internal Medicine, University Medical Center Eppendorf, Hamburg, Germany
| |
Collapse
|
14
|
Bertram KM, Tong O, Royle C, Turville SG, Nasr N, Cunningham AL, Harman AN. Manipulation of Mononuclear Phagocytes by HIV: Implications for Early Transmission Events. Front Immunol 2019; 10:2263. [PMID: 31616434 PMCID: PMC6768965 DOI: 10.3389/fimmu.2019.02263] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Accepted: 09/09/2019] [Indexed: 12/11/2022] Open
Abstract
Mononuclear phagocytes are antigen presenting cells that play a key role in linking the innate and adaptive immune systems. In tissue, these consist of Langerhans cells, dendritic cells and macrophages, all of which express the key HIV entry receptors CD4 and CCR5 making them directly infectible with HIV. Mononuclear phagocytes are the first cells of the immune system to interact with invading pathogens such as HIV. Each cell type expresses a specific repertoire of pathogen binding receptors which triggers pathogen uptake and the release of innate immune cytokines. Langerhans cells and dendritic cells migrate to lymph nodes and present antigens to CD4 T cells, whereas macrophages remain tissue resident. Here we review how HIV-1 manipulates these cells by blocking their ability to produce innate immune cytokines and taking advantage of their antigen presenting cell function in order to gain transport to its primary target cells, CD4 T cells.
Collapse
Affiliation(s)
- Kirstie Melissa Bertram
- School of Medical Sciences, University of Sydney, Sydney, NSW, Australia.,Center for Virus Research, The Westmead Institute for Medical Research, Sydney, NSW, Australia
| | - Orion Tong
- School of Medical Sciences, University of Sydney, Sydney, NSW, Australia.,Center for Virus Research, The Westmead Institute for Medical Research, Sydney, NSW, Australia
| | - Caroline Royle
- School of Medical Sciences, University of Sydney, Sydney, NSW, Australia.,Center for Virus Research, The Westmead Institute for Medical Research, Sydney, NSW, Australia
| | - Stuart Grant Turville
- HIV Biology, Kirby Institute, Kensington, NSW, Australia.,The University of New South Whales, Sydney, NSW, Australia
| | - Najla Nasr
- School of Medical Sciences, University of Sydney, Sydney, NSW, Australia.,Center for Virus Research, The Westmead Institute for Medical Research, Sydney, NSW, Australia
| | - Anthony Lawrence Cunningham
- School of Medical Sciences, University of Sydney, Sydney, NSW, Australia.,Center for Virus Research, The Westmead Institute for Medical Research, Sydney, NSW, Australia
| | - Andrew Nicholas Harman
- School of Medical Sciences, University of Sydney, Sydney, NSW, Australia.,Center for Virus Research, The Westmead Institute for Medical Research, Sydney, NSW, Australia
| |
Collapse
|
15
|
Buffalo CZ, Stürzel CM, Heusinger E, Kmiec D, Kirchhoff F, Hurley JH, Ren X. Structural Basis for Tetherin Antagonism as a Barrier to Zoonotic Lentiviral Transmission. Cell Host Microbe 2019; 26:359-368.e8. [PMID: 31447307 DOI: 10.1016/j.chom.2019.08.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Revised: 07/05/2019] [Accepted: 07/31/2019] [Indexed: 12/25/2022]
Abstract
Tetherin is a host defense factor that physically prevents virion release from the plasma membrane. The Nef accessory protein of simian immunodeficiency virus (SIV) engages the clathrin adaptor AP-2 to downregulate tetherin via its DIWK motif. As human tetherin lacks DIWK, antagonism of tetherin by Nef is a barrier to simian-human transmission of non-human primate lentiviruses. To determine the molecular basis for tetherin counteraction, we reconstituted the AP-2 complex with a simian tetherin and SIV Nef and determined its structure by cryoelectron microscopy (cryo-EM). Nef refolds the first α-helix of the β2 subunit of AP-2 to a β hairpin, creating a binding site for the DIWK sequence. The tetherin binding site in Nef is distinct from those of most other Nef substrates, including MHC class I, CD3, and CD4 but overlaps with the site for the restriction factor SERINC5. This structure explains the dependence of SIVs on tetherin DIWK and consequent barrier to human transmission.
Collapse
Affiliation(s)
- 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
| | - Dorota Kmiec
- Institute of Molecular Virology, Ulm University Medical Center, 89081 Ulm, Germany
| | - Frank Kirchhoff
- Institute of Molecular Virology, Ulm University Medical Center, 89081 Ulm, Germany
| | - 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.
| | - Xuefeng Ren
- Department of Molecular and Cell Biology and California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, CA 94720, USA.
| |
Collapse
|
16
|
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.
Collapse
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.
| |
Collapse
|
17
|
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.
Collapse
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.
| |
Collapse
|
18
|
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.
Collapse
|
19
|
Gutierrez B, Escalera-Zamudio M, Pybus OG. Parallel molecular evolution and adaptation in viruses. Curr Opin Virol 2019; 34:90-96. [PMID: 30703578 PMCID: PMC7102768 DOI: 10.1016/j.coviro.2018.12.006] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Accepted: 12/11/2018] [Indexed: 01/05/2023]
Abstract
Parallel molecular evolution is the independent evolution of the same genotype or phenotype from distinct ancestors. The simple genomes and rapid evolution of many viruses mean they are useful model systems for studying parallel evolution by natural selection. Parallel adaptation occurs in the context of several viral behaviours, including cross-species transmission, drug resistance, and host immune escape, and its existence suggests that at least some aspects of virus evolution and emergence are repeatable and predictable. We introduce examples of virus parallel evolution and summarise key concepts. We outline the difficulties in detecting parallel adaptation using virus genomes, with a particular focus on phylogenetic and structural approaches, and we discuss future approaches that may improve our understanding of the phenomenon.
Collapse
Affiliation(s)
| | | | - Oliver G Pybus
- Department of Zoology, University of Oxford, Oxford, United Kingdom.
| |
Collapse
|
20
|
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.
Collapse
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
| |
Collapse
|
21
|
daSilva LLP, Mardones GA. HIV/SIV-Nef: Pas de trois Choreographies to Evade Immunity. Trends Microbiol 2018; 26:889-891. [PMID: 30287212 DOI: 10.1016/j.tim.2018.09.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Accepted: 09/12/2018] [Indexed: 10/28/2022]
Abstract
Nef is a major pathogenic factor of human and simian immunodeficiency viruses that hijacks protein trafficking through physical interaction with vesicle coats. This alters the subcellular localization of proteins involved in immunity and neutralizes their function. Understanding the structural bases for these interactions could reveal new targets for antiviral intervention.
Collapse
Affiliation(s)
- Luis L P daSilva
- Department of Cell and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo 14049-900, Brazil.
| | - Gonzalo A Mardones
- Department of Physiology, School of Medicine and Center for Interdisciplinary Studies of the Nervous System (CISNe), Universidad Austral de Chile, Valdivia 5110566, Chile; Center for Cell Biology and Biomedicine (CEBICEM), School of Medicine and Science, Universidad San Sebastián, Santiago 7510157, Chile.
| |
Collapse
|
22
|
Chen L, Keppler OT, Schölz C. Post-translational Modification-Based Regulation of HIV Replication. Front Microbiol 2018; 9:2131. [PMID: 30254620 PMCID: PMC6141784 DOI: 10.3389/fmicb.2018.02131] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Accepted: 08/20/2018] [Indexed: 12/13/2022] Open
Abstract
Human immunodeficiency virus (HIV) relies heavily on the host cellular machinery for production of viral progeny. To exploit cellular proteins for replication and to overcome host factors with antiviral activity, HIV has evolved a set of regulatory and accessory proteins to shape an optimized environment for its replication and to facilitate evasion from the immune system. Several cellular pathways are hijacked by the virus to modulate critical steps during the viral life cycle. Thereby, post-translational modifications (PTMs) of viral and cellular proteins gain increasingly attention as modifying enzymes regulate virtually every step of the viral replication cycle. This review summarizes the current knowledge of HIV-host interactions influenced by PTMs with a special focus on acetylation, ubiquitination, and phosphorylation of proteins linked to cellular signaling and viral replication. Insights into these interactions are surmised to aid development of new intervention strategies.
Collapse
Affiliation(s)
- Lin Chen
- Max von Pettenkofer-Institute and Gene Center, Virology, National Reference Center for Retroviruses, Faculty of Medicine, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Oliver T Keppler
- Max von Pettenkofer-Institute and Gene Center, Virology, National Reference Center for Retroviruses, Faculty of Medicine, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Christian Schölz
- Max von Pettenkofer-Institute and Gene Center, Virology, National Reference Center for Retroviruses, Faculty of Medicine, Ludwig-Maximilians-University Munich, Munich, Germany
| |
Collapse
|
23
|
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.
Collapse
|
24
|
Kmiec D, Akbil B, Ananth S, Hotter D, Sparrer KMJ, Stürzel CM, Trautz B, Ayouba A, Peeters M, Yao Z, Stagljar I, Passos V, Zillinger T, Goffinet C, Sauter D, Fackler OT, Kirchhoff F. SIVcol Nef counteracts SERINC5 by promoting its proteasomal degradation but does not efficiently enhance HIV-1 replication in human CD4+ T cells and lymphoid tissue. PLoS Pathog 2018; 14:e1007269. [PMID: 30125328 PMCID: PMC6117100 DOI: 10.1371/journal.ppat.1007269] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Revised: 08/30/2018] [Accepted: 08/08/2018] [Indexed: 12/18/2022] Open
Abstract
SERINC5 is a host restriction factor that impairs infectivity of HIV-1 and other primate lentiviruses and is counteracted by the viral accessory protein Nef. However, the importance of SERINC5 antagonism for viral replication and cytopathicity remained unclear. Here, we show that the Nef protein of the highly divergent SIVcol lineage infecting mantled guerezas (Colobus guereza) is a potent antagonist of SERINC5, although it lacks the CD4, CD3 and CD28 down-modulation activities exerted by other primate lentiviral Nefs. In addition, SIVcol Nefs decrease CXCR4 cell surface expression, suppress TCR-induced actin remodeling, and counteract Colobus but not human tetherin. Unlike HIV-1 Nef proteins, SIVcol Nef induces efficient proteasomal degradation of SERINC5 and counteracts orthologs from highly divergent vertebrate species, such as Xenopus frogs and zebrafish. A single Y86F mutation disrupts SERINC5 and tetherin antagonism but not CXCR4 down-modulation by SIVcol Nef, while mutation of a C-proximal di-leucine motif has the opposite effect. Unexpectedly, the Y86F change in SIVcol Nef had little if any effect on viral replication and CD4+ T cell depletion in preactivated human CD4+ T cells and in ex vivo infected lymphoid tissue. However, SIVcol Nef increased virion infectivity up to 10-fold and moderately increased viral replication in resting peripheral blood mononuclear cells (PBMCs) that were first infected with HIV-1 and activated three or six days later. In conclusion, SIVcol Nef lacks several activities that are conserved in other primate lentiviruses and utilizes a distinct proteasome-dependent mechanism to counteract SERINC5. Our finding that evolutionarily distinct SIVcol Nefs show potent anti-SERINC5 activity supports a relevant role of SERINC5 antagonism for viral fitness in vivo. Our results further suggest this Nef function is particularly important for virion infectivity under conditions of limited CD4+ T cell activation. The accessory protein Nef promotes primate lentiviral replication and enhances the pathogenicity of HIV-1 by mechanisms of immune evasion and enhancing viral infectivity and replication. Here, we show that the evolutionarily most isolated primate lentivirus SIVcol lacks several otherwise conserved Nef functions. Nevertheless, SIVcol Nef potently antagonizes SERINC5, a recently discovered inhibitor of viral infectivity, by down-modulating it from the cell surface and inducing its proteasomal degradation. We identified Y86 in SIVcol Nef as a key determinant of SERINC5 antagonism. Efficient counteraction of SERINC5 did not increase HIV-1 replication in preactivated CD4+ T cells and in ex vivo infected lymphoid tissue but had modest enhancing effects when resting PBMCs were first infected and activated six days later. Evolution of high anti-SERINC5 activity by SIVcol Nef supports a relevant role of this antagonism in vivo, for instance by enhancing virion infectivity under conditions of limited T cell activation.
Collapse
Affiliation(s)
- Dorota Kmiec
- Institute of Molecular Virology, Ulm University Medical Center, Ulm, Germany
| | - Bengisu Akbil
- Institute of Molecular Virology, Ulm University Medical Center, Ulm, Germany
| | - Swetha Ananth
- Department of Infectious Diseases, Integrative Virology, CIID, University Hospital Heidelberg, Heidelberg, Germany
- German Center for Infection Research (DZIF), Partner Site Heidelberg, Heidelberg, Germany
| | - Dominik Hotter
- Institute of Molecular Virology, Ulm University Medical Center, Ulm, Germany
| | | | | | - Birthe Trautz
- Department of Infectious Diseases, Integrative Virology, CIID, University Hospital Heidelberg, Heidelberg, Germany
- German Center for Infection Research (DZIF), Partner Site Heidelberg, Heidelberg, Germany
| | - Ahidjo Ayouba
- TransVIHMI, Institut de Recherche pour le Développement, University of Montpellier, INSERM, Montpellier, France
| | - Martine Peeters
- TransVIHMI, Institut de Recherche pour le Développement, University of Montpellier, INSERM, Montpellier, France
| | - Zhong Yao
- Donnelly Centre, University of Toronto, Ontario, Canada
| | - Igor Stagljar
- Donnelly Centre, University of Toronto, Ontario, Canada
- Departments of Biochemistry and Molecular Genetics, University of Toronto, Ontario, Canada
| | - Vânia Passos
- Institute of Virology, Hannover Medical School, Hannover, Germany
| | - Thomas Zillinger
- Institute of Clinical Chemistry and Clinical Pharmacology, University of Bonn, Bonn, Germany
| | | | - Daniel Sauter
- Institute of Molecular Virology, Ulm University Medical Center, Ulm, Germany
| | - Oliver T. Fackler
- Department of Infectious Diseases, Integrative Virology, CIID, University Hospital Heidelberg, Heidelberg, Germany
- German Center for Infection Research (DZIF), Partner Site Heidelberg, Heidelberg, Germany
| | - Frank Kirchhoff
- Institute of Molecular Virology, Ulm University Medical Center, Ulm, Germany
- * E-mail:
| |
Collapse
|
25
|
Geoghegan JL, Holmes EC. Predicting virus emergence amid evolutionary noise. Open Biol 2018; 7:rsob.170189. [PMID: 29070612 PMCID: PMC5666085 DOI: 10.1098/rsob.170189] [Citation(s) in RCA: 107] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Accepted: 09/24/2017] [Indexed: 12/27/2022] Open
Abstract
The study of virus disease emergence, whether it can be predicted and how it might be prevented, has become a major research topic in biomedicine. Here we show that efforts to predict disease emergence commonly conflate fundamentally different evolutionary and epidemiological time scales, and are likely to fail because of the enormous number of unsampled viruses that could conceivably emerge in humans. Although we know much about the patterns and processes of virus evolution on evolutionary time scales as depicted in family-scale phylogenetic trees, these data have little predictive power to reveal the short-term microevolutionary processes that underpin cross-species transmission and emergence. Truly understanding disease emergence therefore requires a new mechanistic and integrated view of the factors that allow or prevent viruses spreading in novel hosts. We present such a view, suggesting that both ecological and genetic aspects of virus emergence can be placed within a simple population genetic framework, which in turn highlights the importance of host population size and density in determining whether emergence will be successful. Despite this framework, we conclude that a more practical solution to preventing and containing the successful emergence of new diseases entails ongoing virological surveillance at the human–animal interface and regions of ecological disturbance.
Collapse
Affiliation(s)
- Jemma L Geoghegan
- Department of Biological Sciences, Macquarie University, Sydney, New South Wales 2109, Australia
| | - Edward C Holmes
- Marie Bashir Institute for Infectious Diseases and Biosecurity, Charles Perkins Centre, School of Life and Environmental Sciences and Sydney Medical School, The University of Sydney, Sydney, New South Wales 2006, Australia
| |
Collapse
|
26
|
Bourke NM, Napoletano S, Bannan C, Ahmed S, Bergin C, McKnight Á, Stevenson NJ. Control of HIV infection by IFN-α: implications for latency and a cure. Cell Mol Life Sci 2018; 75:775-783. [PMID: 28988399 PMCID: PMC11105398 DOI: 10.1007/s00018-017-2652-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Revised: 08/25/2017] [Accepted: 09/05/2017] [Indexed: 12/23/2022]
Abstract
Viral infections, including HIV, trigger the production of type I interferons (IFNs), which in turn, activate a signalling cascade that ultimately culminates with the expression of anti-viral proteins. Mounting evidence suggests that type I IFNs, in particular IFN-α, play a pivotal role in limiting acute HIV infection. Highly active anti-retroviral treatment reduces viral load and increases life expectancy in HIV positive patients; however, it fails to fully eliminate latent HIV reservoirs. To revisit HIV as a curable disease, this article reviews a body of literature that highlights type I IFNs as mediators in the control of HIV infection, with particular focus on the anti-HIV restriction factors induced and/or activated by IFN-α. In addition, we discuss the relevance of type I IFN treatment in the context of HIV latency reversal, novel therapeutic intervention strategies and the potential for full HIV clearance.
Collapse
Affiliation(s)
- Nollaig M Bourke
- School of Medicine, Trinity Translational Medicine Institute, Trinity College Dublin, Dublin, Ireland
- Department of Medical Gerontology, Mercer's Institute for Successful Ageing, St. James Hospital, Dublin, Ireland
| | - Silvia Napoletano
- School of Biochemistry and Immunology, Trinity College Dublin, Dublin, Ireland
| | - Ciaran Bannan
- School of Biochemistry and Immunology, Trinity College Dublin, Dublin, Ireland
- Department of Genito Urinary Medicine and Infectious Diseases, St. James's Hospital, Dublin, Ireland
| | - Suaad Ahmed
- School of Biochemistry and Immunology, Trinity College Dublin, Dublin, Ireland
| | - Colm Bergin
- Department of Genito Urinary Medicine and Infectious Diseases, St. James's Hospital, Dublin, Ireland
| | - Áine McKnight
- Blizard Institute School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Nigel J Stevenson
- School of Biochemistry and Immunology, Trinity College Dublin, Dublin, Ireland.
| |
Collapse
|
27
|
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.
Collapse
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.
| |
Collapse
|
28
|
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.
Collapse
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
| |
Collapse
|
29
|
Zhang Z, Gu Q, de Manuel Montero M, Bravo IG, Marques-Bonet T, Häussinger D, Münk C. Stably expressed APOBEC3H forms a barrier for cross-species transmission of simian immunodeficiency virus of chimpanzee to humans. PLoS Pathog 2017; 13:e1006746. [PMID: 29267382 PMCID: PMC5739507 DOI: 10.1371/journal.ppat.1006746] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2017] [Accepted: 11/12/2017] [Indexed: 02/07/2023] Open
Abstract
APOBEC3s (A3s) are potent restriction factors of human immunodeficiency virus type 1/simian immunodeficiency viruses (HIV-1/SIV), and can repress cross-species transmissions of lentiviruses. HIV-1 originated from a zoonotic infection of SIV of chimpanzee (SIVcpz) to humans. However, the impact of human A3s on the replication of SIVcpz remains unclear. By using novel SIVcpz reporter viruses, we identified that human APOBEC3B (A3B) and APOBEC3H (A3H) haplotype II strongly reduced the infectivity of SIVcpz, because both of them are resistant to SIVcpz Vifs. We further demonstrated that human A3H inhibited SIVcpz by deaminase dependent as well independent mechanisms. In addition, other stably expressed human A3H haplotypes and splice variants showed strong antiviral activity against SIVcpz. Moreover, most SIV and HIV lineage Vif proteins could degrade chimpanzee A3H, but no Vifs from SIVcpz and SIV of gorilla (SIVgor) lineages antagonized human A3H haplotype II. Expression of human A3H hapII in human T cells efficiently blocked the spreading replication of SIVcpz. The spreading replication of SIVcpz was also restricted by stable A3H in human PBMCs. Thus, we speculate that stably expressed human A3H protects humans against the cross-species transmission of SIVcpz and that SIVcpz spillover to humans may have started in individuals that harbor haplotypes of unstable A3H proteins.
Collapse
Affiliation(s)
- Zeli Zhang
- Clinic for Gastroenterology, Hepatology, and Infectiology, Medical Faculty, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
| | - Qinyong Gu
- Clinic for Gastroenterology, Hepatology, and Infectiology, Medical Faculty, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
| | | | | | - Tomas Marques-Bonet
- Institut Biologia Evolutiva (Universitat Pompeu Fabra/CSIC) ICREA, Barcelona, Spain
| | - Dieter Häussinger
- Clinic for Gastroenterology, Hepatology, and Infectiology, Medical Faculty, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
| | - Carsten Münk
- Clinic for Gastroenterology, Hepatology, and Infectiology, Medical Faculty, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
| |
Collapse
|
30
|
Sousa JD, Müller V, Vandamme AM. The epidemic emergence of HIV: what novel enabling factors were involved? Future Virol 2017. [DOI: 10.2217/fvl-2017-0042] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Humans acquired retroviruses from simians, mainly through bushmeat handling. All epidemically successful HIV groups started to spread in early 20th century, contrasting with the antiquity of T-cell lymphotropic viruses, implying that novel enabling factors were involved in HIV emergence. Here we review the Parenteral Serial Transmission and the Enhanced Heterosexual Transmission hypotheses for the adaptation and early spread of HIV. Epidemic start roughly coincides in time with peak genital ulcer disease in cities, suggesting a major role for sexual transmission. Only ill-adapted and rare HIV groups emerged after approximately 1950, when injections and transfusions attained their maximal levels, suggesting that if parenteral serial transmission was necessary for HIV adaptation, it had to be complemented by sexual transmission for HIV to reach epidemic potential. [Formula: see text]
Collapse
Affiliation(s)
- João Dinis Sousa
- Department of Microbiology & Immunology, Rega Institute for Medical Research, Clinical & Epidemiological Virology, KU Leuven - University of Leuven, B-3000, Leuven, Belgium
- Center for Global Health & Tropical Medicine, Unidade de Microbiologia Médica, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Lisbon, Portugal
| | - Viktor Müller
- Institute of Biology, Eötvös Loránd University, Budapest, Hungary
- Evolutionary Systems Research Group, MTA Centre for Ecological Research, Tihany, Hungary
| | - Anne-Mieke Vandamme
- Department of Microbiology & Immunology, Rega Institute for Medical Research, Clinical & Epidemiological Virology, KU Leuven - University of Leuven, B-3000, Leuven, Belgium
- Center for Global Health & Tropical Medicine, Unidade de Microbiologia Médica, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Lisbon, Portugal
| |
Collapse
|
31
|
Abstract
PURPOSE OF REVIEW HIV-1 infection is of global importance, and still incurs substantial morbidity and mortality. Although major pharmacologic advances over the past two decades have resulted in remarkable HIV-1 control, a cure is still forthcoming. One approach to a cure is to exploit natural mechanisms by which the host restricts HIV-1. Herein, we review past and recent discoveries of HIV-1 restriction factors, a diverse set of host proteins that limit HIV-1 replication at multiple levels, including entry, reverse transcription, integration, translation of viral proteins, and packaging and release of virions. RECENT FINDINGS Recent studies of intracellular HIV-1 restriction have offered unique molecular insights into HIV-1 replication and biology. Studies have revealed insights of how restriction factors drive HIV-1 evolution. Although HIV-1 restriction factors only partially control the virus, their importance is underscored by their effect on HIV-1 evolution and adaptation. The list of host restriction factors that control HIV-1 infection is likely to expand with future discoveries. A deeper understanding of the molecular mechanisms of regulation by these factors will uncover new targets for therapeutic control of HIV-1 infection.
Collapse
Affiliation(s)
- Mary Soliman
- Division of Infectious Diseases, Department of Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Geetha Srikrishna
- Division of Infectious Diseases, Department of Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Ashwin Balagopal
- Division of Infectious Diseases, Department of Medicine, Johns Hopkins University, Baltimore, MD, USA.
| |
Collapse
|
32
|
Abstract
The study of virus disease emergence, whether it can be predicted and how it might be prevented, has become a major research topic in biomedicine. Here we show that efforts to predict disease emergence commonly conflate fundamentally different evolutionary and epidemiological time scales, and are likely to fail because of the enormous number of unsampled viruses that could conceivably emerge in humans. Although we know much about the patterns and processes of virus evolution on evolutionary time scales as depicted in family-scale phylogenetic trees, these data have little predictive power to reveal the short-term microevolutionary processes that underpin cross-species transmission and emergence. Truly understanding disease emergence therefore requires a new mechanistic and integrated view of the factors that allow or prevent viruses spreading in novel hosts. We present such a view, suggesting that both ecological and genetic aspects of virus emergence can be placed within a simple population genetic framework, which in turn highlights the importance of host population size and density in determining whether emergence will be successful. Despite this framework, we conclude that a more practical solution to preventing and containing the successful emergence of new diseases entails ongoing virological surveillance at the human-animal interface and regions of ecological disturbance.
Collapse
Affiliation(s)
- Jemma L Geoghegan
- Department of Biological Sciences, Macquarie University, Sydney, New South Wales 2109, Australia
| | - Edward C Holmes
- Marie Bashir Institute for Infectious Diseases and Biosecurity, Charles Perkins Centre, School of Life and Environmental Sciences and Sydney Medical School, The University of Sydney, Sydney, New South Wales 2006, Australia
| |
Collapse
|
33
|
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.
Collapse
|
34
|
Roy N, Pacini G, Berlioz-Torrent C, Janvier K. Characterization of E3 ligases involved in lysosomal sorting of the HIV-1 restriction factor BST2. J Cell Sci 2017; 130:1596-1611. [PMID: 28320822 PMCID: PMC5450231 DOI: 10.1242/jcs.195412] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Accepted: 02/17/2017] [Indexed: 12/17/2022] Open
Abstract
The cellular protein BST2 (also known as tetherin) acts as a major intrinsic antiviral protein that prevents the release of enveloped viruses by trapping nascent viral particles at the surface of infected cells. Viruses have evolved specific strategies to displace BST2 from viral budding sites in order to promote virus egress. In HIV-1, the accessory protein Vpu counters BST2 antiviral activity and promotes sorting of BST2 for lysosomal degradation. Vpu increases polyubiquitylation of BST2, a post-translation modification required for Vpu-induced BST2 downregulation, through recruitment of the E3 ligase complex SCF adaptors β-TrCP1 and β-TrCP2 (two isoforms encoded by BTRC and FBXW11, respectively). Herein, we further investigate the role of the ubiquitylation machinery in the lysosomal sorting of BST2. Using a small siRNA screen, we highlighted two additional regulators of BST2 constitutive ubiquitylation and sorting to the lysosomes: the E3 ubiquitin ligases NEDD4 and MARCH8. Interestingly, Vpu does not hijack the cellular machinery that is constitutively involved in BST2 ubiquitylation to sort BST2 for degradation in the lysosomes but instead promotes the recognition of BST2 by β-TrCP proteins. Altogether, our results provide further understanding of the mechanisms underlying BST2 turnover in cells. Highlighted Article: We identify two E3 ubiquitin ligases, NEDD4 and MARCH8, as regulators of BST2 (tetherin) – a protein that restricts viral release; we thus provide further understanding of the mechanisms underlying BST2 turnover in cells.
Collapse
Affiliation(s)
- Nicolas Roy
- Inserm, U1016, Institut Cochin, Paris, France.,CNRS, UMR8104, Paris, France.,Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Grégory Pacini
- Inserm, U1016, Institut Cochin, Paris, France.,CNRS, UMR8104, Paris, France.,Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Clarisse Berlioz-Torrent
- Inserm, U1016, Institut Cochin, Paris, France.,CNRS, UMR8104, Paris, France.,Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Katy Janvier
- Inserm, U1016, Institut Cochin, Paris, France .,CNRS, UMR8104, Paris, France.,Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| |
Collapse
|
35
|
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.
Collapse
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
| |
Collapse
|
36
|
Simian Immunodeficiency Virus seroreactivity in inhabitants from rural Cameroon frequently in contact with non-human primates. Virology 2017; 503:76-82. [PMID: 28135660 DOI: 10.1016/j.virol.2016.12.026] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Revised: 12/19/2016] [Accepted: 12/20/2016] [Indexed: 11/21/2022]
Abstract
Central African tropical forests are home to several species of non-human primates (NHPs), infected by Simian Immunodeficiency Virus (SIV). It is well-known that HIV-1 epidemic is due to cross-transmission and adaptation of SIV to humans. The main goal of this work was to investigate if a NHP bite is a risk factor for SIV acquisition. A cross-sectional study was performed in rural Cameroon on 246 bitten individuals (mostly by adult NHPs), matched, according to sex, age, and ethnicity (Bantus and Pygmies), with an equal number of not-bitten subjects. Following a serological assay for a wide range of SIVs, we observed a high level of indeterminate seroreactivity (25.8%) in the total population, whereas 68.9% were sero-negative and 5.3% HIV-1 positive. Bites do not appear to be a risk factor for SIV seroreactivity, in contrast to Simian Foamy Virus and Simian T-Lymphotropic Virus type 1 in the same studied population.
Collapse
|
37
|
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.
Collapse
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
| |
Collapse
|
38
|
Li SX, Barrett BS, Guo K, Santiago ML. Tetherin/BST-2: Restriction Factor or Immunomodulator? Curr HIV Res 2016; 14:235-46. [PMID: 26957198 DOI: 10.2174/1570162x14999160224102752] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Revised: 08/10/2015] [Accepted: 08/11/2015] [Indexed: 11/22/2022]
Abstract
BACKGROUND Cell-mediated immune (CMI) responses are critical for the control of HIV-1 infection and their importance was highlighted by the existence of viral proteins, particularly Vpu and Nef, that antagonize these responses. Pandemic HIV-1 Vpu counteracts Tetherin/BST-2, a host factor that could prevent the release of HIV-1 virions by tethering virions on the cell surface, but a link between Tetherin and HIV-1 CMI responses has not yet been demonstrated in vivo. In vitro, the virological and immunological impact of Tetherin-mediated accumulation of virions ranged from enhanced or diminished cell-to-cell spread to enhanced recognition by virus-specific antibodies for natural killer cellmediated lysis. However, Tetherin-restricted virions could be internalized through an endocytosis motif in the Tetherin cytoplasmic tail. METHODS Given the uncertainties on which in vitro results manifest in vivo and the dearth of knowledge on how Tetherin influences retroviral immunity, in vivo retrovirus infections in mice encoding wild-type, null and endocytosis-defective Tetherin were performed. Here, we review and highlight the results from these in vivo studies. RESULTS Current data suggests that endocytosis-defective Tetherin functions as a potent innate restriction factor. By contrast, endocytosis-competent Tetherin, the form found in most mammals including humans and the form counteracted by HIV-1 Vpu, was linked to stronger CMI responses in mice. CONCLUSION We propose that the main role of endocytosis-competent Tetherin is not to directly restrict retroviral replication, but to promote a more effective CMI response against retroviruses.
Collapse
Affiliation(s)
| | | | | | - Mario L Santiago
- Division of Infectious Diseases, University of Colorado Denver, Mail Stop B-168, 12700 E 19th Avenue, Aurora, CO 80045, USA.
| |
Collapse
|
39
|
Tetherin Antagonism by HIV-1 Group M Nef Proteins. J Virol 2016; 90:10701-10714. [PMID: 27654287 DOI: 10.1128/jvi.01465-16] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Accepted: 09/12/2016] [Indexed: 12/20/2022] Open
Abstract
Although Nef is the viral gene product used by most simian immunodeficiency viruses to overcome restriction by tetherin, this activity was acquired by the Vpu protein of HIV-1 group M due to the absence of sequences in human tetherin that confer susceptibility to Nef. Thus, it is widely accepted that HIV-1 group M uses Vpu instead of Nef to counteract tetherin. Challenging this paradigm, we identified Nef alleles of HIV-1 group M isolates with significant activity against human tetherin. These Nef proteins promoted virus release and tetherin downmodulation from the cell surface and, in the context of vpu-deleted HIV-1 recombinants, enhanced virus replication and resistance to antibody-dependent cell-mediated cytotoxicity (ADCC). Further analysis revealed that the Vpu proteins from several of these viruses lack antitetherin activity, suggesting that under certain circumstances, HIV-1 group M Nef may acquire the ability to counteract tetherin to compensate for the loss of this function by Vpu. These observations illustrate the remarkable plasticity of HIV-1 in overcoming restriction by tetherin and challenge the prevailing view that all HIV-1 group M isolates use Vpu to counteract tetherin. IMPORTANCE Most viruses of HIV-1 group M, the main group of HIV-1 responsible for the global AIDS pandemic, use their Vpu proteins to overcome restriction by tetherin (BST-2 or CD317), which is a transmembrane protein that inhibits virus release from infected cells. Here we show that the Nef proteins of certain HIV-1 group M isolates can acquire the ability to counteract tetherin. These results challenge the current paradigm that HIV-1 group M exclusively uses Vpu to counteract tetherin and underscore the importance of tetherin antagonism for efficient viral replication.
Collapse
|
40
|
Differential Control of BST2 Restriction and Plasmacytoid Dendritic Cell Antiviral Response by Antagonists Encoded by HIV-1 Group M and O Strains. J Virol 2016; 90:10236-10246. [PMID: 27581991 DOI: 10.1128/jvi.01131-16] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Accepted: 08/29/2016] [Indexed: 12/15/2022] Open
Abstract
BST2/tetherin is a type I interferon (IFN-I)-stimulated host factor that restricts the release of HIV-1 by entrapping budding virions at the cell surface. This membrane-associated protein can also engage and activate the plasmacytoid dendritic cell (pDC)-specific immunoglobulin-like transcript 7 (ILT7) inhibitory receptor to downregulate the IFN-I response by pDCs. Pandemic HIV-1 group M uses Vpu (M-Vpu) to counteract the two BST2 isoforms (long and short) that are expressed in human cells. M-Vpu efficiently downregulates surface long BST2, while it displaces short BST2 molecules away from viral assembly sites. We recently found that this attribute is used by M-Vpu to activate the BST2/ILT7-dependent negative-feedback pathway and to suppress pDC IFN-I responses during sensing of infected cells. However, whether this property is conserved in endemic HIV-1 group O, which has evolved Nef (O-Nef) to counteract specifically the long BST2 isoform, remains unknown. In the present study, we validated that O-Nefs have the capacity to downregulate surface BST2 and enhance HIV-1 particle release although less efficiently than M-Vpu. In contrast to M-Vpu, O-Nef did not efficiently enhance viral spread in T cell culture or displace short BST2 from viral assembly sites to prevent its occlusion by tethered HIV-1 particles. Consequently, O-Nef impairs the ability of BST2 to activate negative ILT7 signaling to suppress the IFN-I response by pDC-containing peripheral blood mononuclear cells (PBMCs) during sensing of infected cells. These distinctive features of BST2 counteraction by O-Nefs may in part explain the limited spread of HIV-1 group O in the human population. IMPORTANCE The geographical distributions and prevalences of different HIV-1 groups show large variations. Understanding drivers of distinctive viral spread may aid in the development of therapeutic strategies for controlling the spread of HIV-1 pandemic strains. The differential spread of HIV-1 groups appears to be linked to their capacities to antagonize the long and short isoforms of the BST2 restriction factor. We found that the endemic HIV-1 group O-encoded BST2 antagonist Nef is unable to counteract the restriction mediated by short BST2, a condition that impairs its ability to activate ILT7 and suppress pDC antiviral responses. This is in contrast to the pandemic HIV-1 group M-specified BST2 countermeasure Vpu, which displays a diverse array of mechanisms to counteract short and long BST2 isoforms, an attribute that allows the effective control of pDC antiviral responses. These findings may help explain the limited spread of HIV-1 group O as well as the continued predominance of HIV-1 group M throughout the world.
Collapse
|
41
|
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.
Collapse
|
42
|
Cell Surface Downregulation of NK Cell Ligands by Patient-Derived HIV-1 Vpu and Nef Alleles. J Acquir Immune Defic Syndr 2016; 72:1-10. [PMID: 26656785 DOI: 10.1097/qai.0000000000000917] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
OBJECTIVE HIV-1 Vpu and Nef proteins downregulate cell surface levels of natural killer (NK) cell ligands but functional consequences of individual downregulation events are unclear. We tested how well-conserved NK cell ligand downregulation is among Vpu and Nef variants isolated from chronic HIV patients. METHODS Proviral vpu and nef sequences were amplified from 27 chronic HIV patients, subcloned, and tested for their ability to downregulate cell surface receptors. RESULTS Cell surface downregulation of CD4, CD317/tetherin, and major histocompatibility complex class 1 that exert biological functions other than NK cell activation were well conserved among patient-derived Vpu and Nef variants. Among NK cell ligands, NK-T-B-antigen, poliovirus receptor, and UL16-binding protein were identified as main targets for Vpu and Nef, the downregulation of which by at least 1 viral protein was highly conserved. NK cell ligands displayed specific sensitivity to Vpu (NK-T-B-antigen) or Nef (poliovirus receptor), and downregulation of cell surface UL16-binding protein was identified as a novel and highly conserved activity of HIV-1 Vpu but not Nef. CONCLUSIONS The conservation of downregulation of major NK cell ligands by either HIV-1 Vpu or Nef suggests an important pathophysiological role of this activity, which may impact the acute but not the chronic phase of HIV infection.
Collapse
|
43
|
Abstract
The HIV genome encodes a small number of viral proteins (i.e., 16), invariably establishing cooperative associations among HIV proteins and between HIV and host proteins, to invade host cells and hijack their internal machineries. As a known example, the HIV envelope glycoprotein GP120 is closely associated with GP41 for viral entry. From a genome-wide perspective, a hypothesis can be worked out to determine whether 16 HIV proteins could develop 120 possible pairwise associations either by physical interactions or by functional associations mediated via HIV or host molecules. Here, we present the first systematic review of experimental evidence on HIV genome-wide protein associations using a large body of publications accumulated over the past 3 decades. Of 120 possible pairwise associations between 16 HIV proteins, at least 34 physical interactions and 17 functional associations have been identified. To achieve efficient viral replication and infection, HIV protein associations play essential roles (e.g., cleavage, inhibition, and activation) during the HIV life cycle. In either a dispensable or an indispensable manner, each HIV protein collaborates with another viral protein to accomplish specific activities that precisely take place at the proper stages of the HIV life cycle. In addition, HIV genome-wide protein associations have an impact on anti-HIV inhibitors due to the extensive cross talk between drug-inhibited proteins and other HIV proteins. Overall, this study presents for the first time a comprehensive overview of HIV genome-wide protein associations, highlighting meticulous collaborations between all viral proteins during the HIV life cycle.
Collapse
Affiliation(s)
- Guangdi Li
- Department of Metabolism and Endocrinology, Metabolic Syndrome Research Center, Key Laboratory of Diabetes Immunology, Ministry of Education, National Clinical Research Center for Metabolic Diseases, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China KU Leuven-University of Leuven, Rega Institute for Medical Research, Department of Microbiology and Immunology, Leuven, Belgium
| | - Erik De Clercq
- KU Leuven-University of Leuven, Rega Institute for Medical Research, Department of Microbiology and Immunology, Leuven, Belgium
| |
Collapse
|
44
|
D186/D190 is an allele-dependent determinant of HIV-1 Nef function. Virology 2016; 498:44-56. [PMID: 27560372 DOI: 10.1016/j.virol.2016.08.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2016] [Revised: 08/12/2016] [Accepted: 08/13/2016] [Indexed: 01/23/2023]
Abstract
The HIV-1 pathogenesis factor Nef interacts with numerous ligands to affect cellular vesicular transport, signal transduction and cytoskeletal dynamics. While most Nef functions depend on multivalent protein interaction motifs, disrupting actin dynamics requires a motif that specifically recruits the host kinase PAK2. An adjacent aspartate was recently predicted to mediate Nef-β-catenin interactions. We report here that β-catenin can be co-immunoprecipitated with Nef.GFP from Jurkat T cell lysates. This association is conserved among lentiviral Nef proteins but does not involve classical Nef protein interaction motifs, including the critical aspartate. While aspartate-to-alanine mutations impaired cell surface receptor downregulation and interference with actin dynamics and cell motility by HIV-1 NA7 Nef, analogous mutations did not affect HIV-1 SF2 Nef function. These allelic differences were determined by a proximal lysine/arginine polymorphism. These results emphasize differences between Nef alleles regarding the functional role of individual residues and underscore the need for allele-specific structure-function analyses.
Collapse
|
45
|
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.
Collapse
|
46
|
|
47
|
HIV-1 Vpu Antagonizes CD317/Tetherin by Adaptor Protein-1-Mediated Exclusion from Virus Assembly Sites. J Virol 2016; 90:6709-6723. [PMID: 27170757 DOI: 10.1128/jvi.00504-16] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Accepted: 05/06/2016] [Indexed: 01/22/2023] Open
Abstract
UNLABELLED The host cell restriction factor CD317/tetherin traps virions at the surface of producer cells to prevent their release. The HIV-1 accessory protein Vpu antagonizes this restriction. Vpu reduces the cell surface density of the restriction factor and targets it for degradation; however, these activities are dispensable for enhancing particle release. Instead, Vpu has been suggested to antagonize CD317/tetherin by preventing recycling of internalized CD317/tetherin to the cell surface, blocking anterograde transport of newly synthesized CD317/tetherin, and/or displacing the restriction factor from virus assembly sites at the plasma membrane. At the molecular level, antagonism relies on the physical interaction of Vpu with CD317/tetherin. Recent findings suggested that phosphorylation of a diserine motif enables Vpu to bind to adaptor protein 1 (AP-1) trafficking complexes via two independent interaction motifs and to couple CD317/tetherin to the endocytic machinery. Here, we used a panel of Vpu proteins with specific mutations in individual interaction motifs to define which interactions are required for antagonism of CD317/tetherin. Impairing recycling or anterograde transport of CD317/tetherin to the plasma membrane was insufficient for antagonism. In contrast, excluding CD317/tetherin from HIV-1 assembly sites depended on Vpu motifs for interaction with AP-1 and CD317/tetherin and correlated with antagonism of the particle release restriction. Consistently, interference with AP-1 function or its expression blocked these Vpu activities. Our results define displacement from HIV-1 assembly sites as active principle of CD317/tetherin antagonism by Vpu and support a role of tripartite complexes between Vpu, AP-1, and CD317/tetherin in this process. IMPORTANCE CD317/tetherin poses an intrinsic barrier to human immunodeficiency virus type 1 (HIV-1) replication in human cells by trapping virus particles at the surface of producer cells and thereby preventing their release. The viral protein Vpu antagonizes this restriction, and molecular interactions with the restriction factor and adaptor protein complex 1 (AP-1) were suggested to mediate this activity. Vpu modulates intracellular trafficking of CD317/tetherin and excludes the restriction factor from HIV-1 assembly sites at the plasma membrane, but the relative contribution of these effects to antagonism remain elusive. Using a panel of Vpu mutants, as well as interference with AP-1 function and expression, we show here that Vpu antagonizes CD317/tetherin by blocking its recruitment to viral assembly sites in an AP-1-dependent manner. These results refine our understanding of the molecular mechanisms of CD317/tetherin antagonism and suggest complexes of Vpu with the restriction factor and AP-1 as targets for potential therapeutic intervention.
Collapse
|
48
|
Tebit DM, Patel H, Ratcliff A, Alessandri E, Liu J, Carpenter C, Plantier JC, Arts EJ. HIV-1 Group O Genotypes and Phenotypes: Relationship to Fitness and Susceptibility to Antiretroviral Drugs. AIDS Res Hum Retroviruses 2016; 32:676-88. [PMID: 26861573 DOI: 10.1089/aid.2015.0318] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Despite only 30,000 group O HIV-1 infections, a similar genetic diversity is observed among the O subgroups H (head) and T (tail) (previously described as subtypes A, B) as in the 9 group M subtypes (A-K). Group O isolates bearing a cysteine at reverse transcriptase (RT) position 181, predominantly the H strains are intrinsically resistant to non-nucleoside reverse transcriptase inhibitors (NNRTIs). However, their susceptibility to newer antiretroviral drugs such as etravirine, maraviroc, raltegravir (RAL), and elvitegravir (EVG) remains relatively unknown. We tested a large collection of HIV-1 group O strains for their susceptibility to four classes of antiretroviral drugs namely nucleoside RT, non-nucleoside RT, integrase, and entry inhibitors knowing in advance the intrinsic resistance to NNRTIs. Drug target regions were sequenced to determine various polymorphisms and were phylogenetically analyzed. Replication kinetics and fitness assays were performed in U87-CD4(+)CCR5 and CXCR4 cells and peripheral blood mononuclear cells. With all antiretroviral drugs, group O HIV-1 showed higher variability in IC50 values than group M HIV-1. The mean IC50 values for entry and nucleoside reverse transcriptase inhibitor (NRTI) were similar for group O and M HIV-1 isolates. Despite similar susceptibility to maraviroc, the various phenotypic algorithms failed to predict CXCR4 usage based on the V3 Env sequences of group O HIV-1 isolates. Decreased sensitivity of group O HIV-1 to integrase or NNRTIs had no relation to replicative fitness. Group O HIV-1 isolates were 10-fold less sensitive to EVG inhibition than group M HIV-1. These findings suggest that in regions where HIV-1 group O is endemic, first line treatment regimens combining two NRTIs with RAL may provide more sustained virologic responses than the standard regimens involving an NNRTI or protease inhibitors.
Collapse
Affiliation(s)
- Denis M. Tebit
- Division of Infectious Diseases, Case Western Reserve University, Cleveland, Ohio
| | - Hamish Patel
- Division of Infectious Diseases, Case Western Reserve University, Cleveland, Ohio
| | - Annette Ratcliff
- Division of Infectious Diseases, Case Western Reserve University, Cleveland, Ohio
| | | | - Joseph Liu
- Division of Infectious Diseases, Case Western Reserve University, Cleveland, Ohio
| | - Crystal Carpenter
- Division of Infectious Diseases, Case Western Reserve University, Cleveland, Ohio
| | | | - Eric J. Arts
- Division of Infectious Diseases, Case Western Reserve University, Cleveland, Ohio
| |
Collapse
|
49
|
HIV Genome-Wide Protein Associations: a Review of 30 Years of Research. Microbiol Mol Biol Rev 2016; 80:679-731. [PMID: 27357278 DOI: 10.1128/mmbr.00065-15] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The HIV genome encodes a small number of viral proteins (i.e., 16), invariably establishing cooperative associations among HIV proteins and between HIV and host proteins, to invade host cells and hijack their internal machineries. As a known example, the HIV envelope glycoprotein GP120 is closely associated with GP41 for viral entry. From a genome-wide perspective, a hypothesis can be worked out to determine whether 16 HIV proteins could develop 120 possible pairwise associations either by physical interactions or by functional associations mediated via HIV or host molecules. Here, we present the first systematic review of experimental evidence on HIV genome-wide protein associations using a large body of publications accumulated over the past 3 decades. Of 120 possible pairwise associations between 16 HIV proteins, at least 34 physical interactions and 17 functional associations have been identified. To achieve efficient viral replication and infection, HIV protein associations play essential roles (e.g., cleavage, inhibition, and activation) during the HIV life cycle. In either a dispensable or an indispensable manner, each HIV protein collaborates with another viral protein to accomplish specific activities that precisely take place at the proper stages of the HIV life cycle. In addition, HIV genome-wide protein associations have an impact on anti-HIV inhibitors due to the extensive cross talk between drug-inhibited proteins and other HIV proteins. Overall, this study presents for the first time a comprehensive overview of HIV genome-wide protein associations, highlighting meticulous collaborations between all viral proteins during the HIV life cycle.
Collapse
|
50
|
Matsuda K, Chen CY, Whitted S, Chertova E, Roser DJ, Wu F, Plishka RJ, Ourmanov I, Buckler-White A, Lifson JD, Strebel K, Hirsch VM. Enhanced antagonism of BST-2 by a neurovirulent SIV envelope. J Clin Invest 2016; 126:2295-307. [PMID: 27159392 PMCID: PMC4887162 DOI: 10.1172/jci83725] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Accepted: 03/22/2016] [Indexed: 11/17/2022] Open
Abstract
Current antiretroviral therapy (ART) is not sufficient to completely suppress disease progression in the CNS, as indicated by the rising incidence of HIV-1-associated neurocognitive disorders (HAND) among infected individuals on ART. It is not clear why some HIV-1-infected patients develop HAND, despite effective repression of viral replication in the circulation. SIV-infected nonhuman primate models are widely used to dissect the mechanisms of viral pathogenesis in the CNS. Here, we identified 4 amino acid substitutions in the cytoplasmic tail of viral envelope glycoprotein gp41 of the neurovirulent virus SIVsm804E that enhance replication in macrophages and associate with enhanced antagonism of the host restriction factor BM stromal cell antigen 2 (BST-2). Rhesus macaques were inoculated with a variant of the parental virus SIVsmE543-3 that had been engineered to contain the 4 amino acid substitutions present in gp41 of SIVsm804E. Compared with WT virus-infected controls, animals infected with mutant virus exhibited higher viral load in cerebrospinal fluid. Together, these results are consistent with a potential role for BST-2 in the CNS microenvironment and suggest that BST-2 antagonists may serve as a possible target for countermeasures against HAND.
Collapse
Affiliation(s)
- Kenta Matsuda
- Laboratory of Molecular Microbiology, National Institute of Allergy and Infectious Diseases (NIAID), NIH, Bethesda, Maryland, USA
| | - Chia-Yen Chen
- Laboratory of Molecular Microbiology, National Institute of Allergy and Infectious Diseases (NIAID), NIH, Bethesda, Maryland, USA
| | - Sonya Whitted
- Laboratory of Molecular Microbiology, National Institute of Allergy and Infectious Diseases (NIAID), NIH, Bethesda, Maryland, USA
| | - Elena Chertova
- AIDS and Cancer Virus Program, Leidos Biomedical Research Inc., Frederick National Laboratory for Cancer Research, Frederick, Maryland, USA
| | - David J. Roser
- AIDS and Cancer Virus Program, Leidos Biomedical Research Inc., Frederick National Laboratory for Cancer Research, Frederick, Maryland, USA
| | - Fan Wu
- Laboratory of Molecular Microbiology, National Institute of Allergy and Infectious Diseases (NIAID), NIH, Bethesda, Maryland, USA
| | - Ronald J. Plishka
- Laboratory of Molecular Microbiology, National Institute of Allergy and Infectious Diseases (NIAID), NIH, Bethesda, Maryland, USA
| | - Ilnour Ourmanov
- Laboratory of Molecular Microbiology, National Institute of Allergy and Infectious Diseases (NIAID), NIH, Bethesda, Maryland, USA
| | - Alicia Buckler-White
- Laboratory of Molecular Microbiology, National Institute of Allergy and Infectious Diseases (NIAID), NIH, Bethesda, Maryland, USA
| | - Jeffrey D. Lifson
- AIDS and Cancer Virus Program, Leidos Biomedical Research Inc., Frederick National Laboratory for Cancer Research, Frederick, Maryland, USA
| | - Klaus Strebel
- Laboratory of Molecular Microbiology, National Institute of Allergy and Infectious Diseases (NIAID), NIH, Bethesda, Maryland, USA
| | - Vanessa M. Hirsch
- Laboratory of Molecular Microbiology, National Institute of Allergy and Infectious Diseases (NIAID), NIH, Bethesda, Maryland, USA
| |
Collapse
|