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Virgilio MC, Ramnani B, Chen T, Disbennett WM, Lubow J, Welch JD, Collins KL. HIV-1 Vpr combats the PU.1-driven antiviral response in primary human macrophages. Nat Commun 2024; 15:5514. [PMID: 38951492 PMCID: PMC11217462 DOI: 10.1038/s41467-024-49635-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Accepted: 06/12/2024] [Indexed: 07/03/2024] Open
Abstract
HIV-1 Vpr promotes efficient spread of HIV-1 from macrophages to T cells by transcriptionally downmodulating restriction factors that target HIV-1 Envelope protein (Env). Here we find that Vpr induces broad transcriptomic changes by targeting PU.1, a transcription factor necessary for expression of host innate immune response genes, including those that target Env. Consistent with this, we find silencing PU.1 in infected macrophages lacking Vpr rescues Env. Vpr downmodulates PU.1 through a proteasomal degradation pathway that depends on physical interactions with PU.1 and DCAF1, a component of the Cul4A E3 ubiquitin ligase. The capacity for Vpr to target PU.1 is highly conserved across primate lentiviruses. In addition to impacting infected cells, we find that Vpr suppresses expression of innate immune response genes in uninfected bystander cells, and that virion-associated Vpr can degrade PU.1. Together, we demonstrate Vpr counteracts PU.1 in macrophages to blunt antiviral immune responses and promote viral spread.
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Affiliation(s)
- Maria C Virgilio
- Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, MI, USA
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI, USA
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Barkha Ramnani
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Thomas Chen
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI, USA
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI, USA
| | - W Miguel Disbennett
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI, USA
- Post-Baccalaureate Research Education Program (PREP), University of Michigan, Ann Arbor, MI, USA
- University of Pennsylvania, Philadelphia, PA, USA
| | - Jay Lubow
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI, USA
- ImmunoVec, Inc., Los Angeles, CA, USA
| | - Joshua D Welch
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI, USA
- Department of Computer Science and Engineering, University of Michigan, Ann Arbor, USA
| | - Kathleen L Collins
- Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, MI, USA.
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA.
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI, USA.
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2
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Virgilio MC, Ramnani B, Chen T, Disbennett WM, Lubow J, Welch JD, Collins KL. HIV-1 Vpr combats the PU.1-driven antiviral response in primary human macrophages. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.03.21.533528. [PMID: 36993393 PMCID: PMC10055223 DOI: 10.1101/2023.03.21.533528] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
HIV-1 Vpr promotes efficient spread of HIV-1 from macrophages to T cells by transcriptionally downmodulating restriction factors that target HIV-1 Envelope protein (Env). Here we find that Vpr induces broad transcriptomic changes by targeting PU.1, a transcription factor necessary for expression of host innate immune response genes, including those that target Env. Consistent with this, we find silencing PU.1 in infected macrophages lacking Vpr rescues Env. Vpr downmodulates PU.1 through a proteasomal degradation pathway that depends on physical interactions with PU.1 and DCAF1, a component of the Cul4A E3 ubiquitin ligase. The capacity for Vpr to target PU.1 is highly conserved across primate lentiviruses. In addition to impacting infected cells, we find that Vpr suppresses expression of innate immune response genes in uninfected bystander cells, and that virion-associated Vpr can degrade PU.1. Together, we demonstrate Vpr counteracts PU.1 in macrophages to blunt antiviral immune responses and promote viral spread.
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3
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Iwamoto Y, Ye AA, Shirazinejad C, Hurley JH, Drubin DG. Kinetic investigation reveals an HIV-1 Nef-dependent increase in AP-2 recruitment and productivity at endocytic sites. Mol Biol Cell 2024; 35:ar9. [PMID: 37938925 PMCID: PMC10881171 DOI: 10.1091/mbc.e23-04-0126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Revised: 10/24/2023] [Accepted: 11/02/2023] [Indexed: 11/10/2023] Open
Abstract
The HIV-1 accessory protein Nef hijacks clathrin adaptors to degrade or mislocalize host proteins involved in antiviral defenses. Here, using quantitative live-cell microscopy in genome-edited Jurkat cells, we investigate the impact of Nef on clathrin-mediated endocytosis (CME), a major pathway for membrane protein internalization in mammalian cells. Nef is recruited to CME sites on the plasma membrane, and this recruitment is associated with an increase in the recruitment and lifetime of the CME coat protein AP-2 and the late-arriving CME protein dynamin2. Furthermore, we find that CME sites that recruit Nef are more likely to recruit dynamin2 and transferrin, suggesting that Nef recruitment to CME sites promotes site maturation to ensure high efficiency in host protein downregulation. Implications of these observations for HIV-1 infection are discussed.
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Affiliation(s)
- Yuichiro Iwamoto
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720
| | - Anna A. Ye
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720
| | - Cyna Shirazinejad
- Biophysics Graduate Group, University of California, Berkeley, Berkeley, CA 94720
| | - James H. Hurley
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720
- California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, CA 94720
- Biophysics Graduate Group, University of California, Berkeley, Berkeley, CA 94720
- Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA 94720
| | - David G. Drubin
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720
- California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, CA 94720
- Biophysics Graduate Group, University of California, Berkeley, Berkeley, CA 94720
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4
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Gao Y, Ju Y, Ren X, Zhang L, Yin X. Enhanced infection efficiency and cytotoxicity mediated by vpx-containing lentivirus in chimeric antigen receptor macrophage (CAR-M). Heliyon 2023; 9:e21886. [PMID: 38058430 PMCID: PMC10696197 DOI: 10.1016/j.heliyon.2023.e21886] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 09/26/2023] [Accepted: 10/31/2023] [Indexed: 12/08/2023] Open
Abstract
Genetically modified macrophage infusion has been proven to be a novel treatment for cancer. One of the most important processes in macrophage-based therapy is the efficient transfer of genes. HIV-1-derived lentiviruses were widely used as delivery vectors in chimeric antigen receptor T and NK cell construction. While macrophages are relatively refractory to this lentiviral vector transduction as a result of the myeloid-specific restriction factor SAMHD1, which inhibited the virion cycle through exhausting the dNTPs pool and degradating RNAs. An efficient macrophage transduction strategy has been developed via packaging the HIV-2 accessory protein Vpx into the virion. Vpx counteracts SAMHD1 through CRL4 (DCAF1) E3 ubiquitin ligase mediated SAMHD1 degradation, yet the influence by the introduction of Vpx on macrophage has not been fully evaluated. Here, we constructed the chimeric lentiviral vector HIV-1-Vpx and systematically analyzed the infection efficiency of this vector in time-dependent manner. Our results showed that the simplified chimeric virus exhibited dramatically enhanced infection in human macrophages compared to normal lentivirus. Moreover, transcriptome sequencing was performed to evaluate the cellular status after chimeric virus infection. The sequencing results indicated that Vpx introduction promoted macrophage remodeling towards a proinflammatory phenotype, without affecting classic M1/M2 cell surface markers. Our results suggest that the Vpx-containing lentivirus could be used as an ideal tool for the generation of genetically engineered macrophages with high gene transfer efficiency and poised proinflammatory gene sets, especially for solid tumor treatment.
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Affiliation(s)
- Yun Gao
- Applied Biology Laboratory, College of Pharmaceutical and Biological Engineering, Shenyang University of Chemical Technology, Shenyang, 110142, China
| | - Yue Ju
- Roc Rock Biotechnology (Shenzhen), Shenzhen, 518118, China
| | - Xiaomeng Ren
- Applied Biology Laboratory, College of Pharmaceutical and Biological Engineering, Shenyang University of Chemical Technology, Shenyang, 110142, China
| | - Luo Zhang
- Research Center of Bioengineering, the Medical Innovation Research Division of Chinese PLA General Hospital, Beijing, 100853, China
| | - Xiushan Yin
- Applied Biology Laboratory, College of Pharmaceutical and Biological Engineering, Shenyang University of Chemical Technology, Shenyang, 110142, China
- Roc Rock Biotechnology (Shenzhen), Shenzhen, 518118, China
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Iwamoto Y, Ye A, Shirazinejad C, Hurley JH, Drubin DG. Kinetic investigation reveals an HIV-1 Nef-dependent increase in AP-2 recruitment and productivity at endocytic sites. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.18.537262. [PMID: 37131815 PMCID: PMC10153213 DOI: 10.1101/2023.04.18.537262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Lentiviruses express non-enzymatic accessory proteins whose function is to subvert cellular machinery in the infected host. The HIV-1 accessory protein Nef hijacks clathrin adaptors to degrade or mislocalize host proteins involved in antiviral defenses. Here, we investigate the interaction between Nef and clathrin-mediated endocytosis (CME), a major pathway for membrane protein internalization in mammalian cells, using quantitative live-cell microscopy in genome-edited Jurkat cells. Nef is recruited to CME sites on the plasma membrane, and this recruitment correlates with an increase in the recruitment and lifetime of CME coat protein AP-2 and late-arriving CME protein dynamin2. Furthermore, we find that CME sites that recruit Nef are more likely to recruit dynamin2, suggesting that Nef recruitment to CME sites promotes CME site maturation to ensure high efficiency in host protein downregulation.
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Affiliation(s)
- Yuichiro Iwamoto
- Department of Molecular and Cell Biology, University of California Berkeley; Berkeley CA 94720, USA
| | - Anna Ye
- Department of Molecular and Cell Biology, University of California Berkeley; Berkeley CA 94720, USA
| | - Cyna Shirazinejad
- Biophysics Graduate Group, University of California, Berkeley, Berkeley, CA 94720, USA
| | - James H Hurley
- Department of Molecular and Cell Biology, University of California Berkeley; Berkeley CA 94720, USA
- California Institute for Quantitative Biosciences, University of California, Berkeley, CA 94720, USA
- Biophysics Graduate Group, University of California, Berkeley, Berkeley, CA 94720, USA
- Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA 94720, USA
| | - David G Drubin
- Department of Molecular and Cell Biology, University of California Berkeley; Berkeley CA 94720, USA
- California Institute for Quantitative Biosciences, University of California, Berkeley, CA 94720, USA
- Biophysics Graduate Group, University of California, Berkeley, Berkeley, CA 94720, USA
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6
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Fisher K, Schlub TE, Boyer Z, Rasmussen TA, Rhodes A, Hoh R, Hecht FM, Deeks SG, Lewin SR, Palmer S. Unequal distribution of genetically-intact HIV-1 proviruses in cells expressing the immune checkpoint markers PD-1 and/or CTLA-4. Front Immunol 2023; 14:1064346. [PMID: 36776833 PMCID: PMC9909745 DOI: 10.3389/fimmu.2023.1064346] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2022] [Accepted: 01/12/2023] [Indexed: 01/27/2023] Open
Abstract
Introduction HIV-1 persists in resting CD4+ T-cells despite antiretroviral therapy (ART). Determining the cell surface markers that enrich for genetically-intact HIV-1 genomes is vital in developing targeted curative strategies. Previous studies have found that HIV-1 proviral DNA is enriched in CD4+ T-cells expressing the immune checkpoint markers programmed cell death protein-1 (PD-1) or cytotoxic T-lymphocyte associated protein-4 (CTLA-4). There has also been some success in blocking these markers in an effort to reverse HIV-1 latency. However, it remains unclear whether cells expressing PD-1 and/or CTLA-4 are enriched for genetically-intact, and potentially replication-competent, HIV-1 genomes. Methods We obtained peripheral blood from 16 HIV-1-infected participants, and paired lymph node from four of these participants, during effective ART. Memory CD4+ T-cells from either site were sorted into four populations: PD-1-CTLA-4- (double negative, DN), PD-1+CTLA-4- (PD-1+), PD-1-CTLA-4+ (CTLA-4+) and PD-1+CTLA-4+ (double positive, DP). We performed an exploratory study using the full-length individual proviral sequencing (FLIPS) assay to identify genetically-intact and defective genomes from each subset, as well as HIV-1 genomes with specific intact open reading frames (ORFs). Results and Discussion In peripheral blood, we observed that proviruses found within PD-1+ cells are more likely to have intact ORFs for genes such as tat, rev and nef compared to DN, CTLA-4+ and DP cells, all of which may contribute to HIV-1 persistence. Conversely, we observed that CTLA-4 expression is a marker for cells harbouring HIV-1 provirus that is more likely to be defective, containing low levels of these intact ORFs. In the lymph node, we found evidence that CTLA-4+ cells contain lower levels of HIV-1 provirus compared to the other cell subsets. Importantly, however, we observed significant participant variation in the enrichment of HIV-1 proviruses with intact genomes or specific intact ORFs across these memory CD4+ T-cell subsets, and therefore consideration of additional cellular markers will likely be needed to consistently identify cells harbouring latent, and potentially replication-competent, HIV-1.
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Affiliation(s)
- Katie Fisher
- Centre for Virus Research, The Westmead Institute of Medical Research, The University of Sydney, Sydney, NSW, Australia.,Sydney Medical School, Westmead Clinical School, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia
| | - Timothy E Schlub
- Sydney School of Public Health, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia
| | - Zoe Boyer
- Centre for Virus Research, The Westmead Institute of Medical Research, The University of Sydney, Sydney, NSW, Australia.,Sydney Medical School, Westmead Clinical School, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia
| | - Thomas A Rasmussen
- Department of Infectious Diseases, The University of Melbourne at The Doherty Institute for Infection and Immunity, Melbourne, VIC, Australia.,Department of Infectious Diseases, Aarhus University Hospital, Aarhus, Denmark
| | - Ajantha Rhodes
- Department of Infectious Diseases, The University of Melbourne at The Doherty Institute for Infection and Immunity, Melbourne, VIC, Australia
| | - Rebecca Hoh
- Division of HIV, Infectious Diseases and Global Medicine, Department of Medicine, Zuckerberg San Francisco General Hospital, University of California San Francisco, San Francisco, CA, United States
| | - Frederick M Hecht
- Division of HIV, Infectious Diseases and Global Medicine, Department of Medicine, Zuckerberg San Francisco General Hospital, University of California San Francisco, San Francisco, CA, United States
| | - Steven G Deeks
- Division of HIV, Infectious Diseases and Global Medicine, Department of Medicine, Zuckerberg San Francisco General Hospital, University of California San Francisco, San Francisco, CA, United States
| | - Sharon R Lewin
- Department of Infectious Diseases, The University of Melbourne at The Doherty Institute for Infection and Immunity, Melbourne, VIC, Australia.,Department of Infectious Diseases, Alfred Hospital and Monash University, Melbourne, VIC, Australia.,Victorian Infectious Diseases Service, Royal Melbourne Hospital at The Doherty Institute for Infection and Immunity, Melbourne, VIC, Australia
| | - Sarah Palmer
- Centre for Virus Research, The Westmead Institute of Medical Research, The University of Sydney, Sydney, NSW, Australia.,Sydney Medical School, Westmead Clinical School, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia
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7
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LL-37 antimicrobial peptide and heterologous prime-boost vaccination regimen significantly induce HIV-1 Nef-Vpr antigen- and virion-specific immune responses in mice. Biotechnol Lett 2023; 45:33-45. [PMID: 36550339 DOI: 10.1007/s10529-022-03339-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Revised: 11/20/2022] [Accepted: 12/09/2022] [Indexed: 12/24/2022]
Abstract
OBJECTIVES HIV infection still remains a leading cause of morbidity and mortality worldwide. The inability of highly-active antiretroviral therapy in HIV-1 eradication led to development of therapeutic vaccines. Exploiting effective immunogenic constructs and potent delivery systems are important to generate effective therapeutic vaccines, and overcome their poor membrane permeability. Among HIV-1 proteins, the Nef and Vpr proteins can be considered as antigen candidates in vaccine design. METHODS In this study, the immunogenicity of Nef-Vpr antigen candidate in different regimens along with antimicrobial peptide LL-37 (as a DNA carrier) and Montanide 720 (as an adjuvant) was studied in mice. Moreover, the secretion of cytokines was assessed in virion-exposed mice lymphocytes in vitro. RESULTS Our data indicated that groups immunized with the homologous protein + Montanide regimen (group 1), and also the heterologous DNA + LL-37 prime/protein + Montanide boost regimen (group 2) could significantly generate strong immune responses as compared to groups immunized with the DNA constructs (groups 3 & 4). Moreover, immunization of mice with the homologous DNA + LL-37 regimen in low dose of DNA (5 µg) could induce higher immune responses than the homologous naked DNA regimen in high dose of DNA (50 µg) indicating the role of LL-37 as a cell penetrating peptide. Additionally, the heterologous DNA + LL-37 prime/protein + Montanide boost regimen (group 2) induced significantly IFN-gamma secretion from virion-exposed lymphocytes in vitro. CONCLUSION Generally, the use of LL-37 for DNA delivery, Montanide 720 as an adjuvant, and heterologous DNA prime/protein boost strategy could significantly increase IgG2a, IFN-gamma, and Granzyme B, and maintain cytokine secretion after exposure to virions. Indeed, the heterologous DNA + LL-37 prime/protein + Montanide boost regimen can be considered as a potent strategy for development of therapeutic HIV vaccines.
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Hooy RM, Iwamoto Y, Tudorica DA, Ren X, Hurley JH. Self-assembly and structure of a clathrin-independent AP-1:Arf1 tubular membrane coat. SCIENCE ADVANCES 2022; 8:eadd3914. [PMID: 36269825 PMCID: PMC9586487 DOI: 10.1126/sciadv.add3914] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 09/01/2022] [Indexed: 05/28/2023]
Abstract
The adaptor protein (AP) complexes not only form the inner layer of clathrin coats but also have clathrin-independent roles in membrane traffic whose mechanisms are unknown. HIV-1 Nef hijacks AP-1 to sequester major histocompatibility complex class I (MHC-I), evading immune detection. We found that AP-1:Arf1:Nef:MHC-I forms a coat on tubulated membranes without clathrin and determined its structure. The coat assembles via Arf1 dimer interfaces. AP-1-positive tubules are enriched in cells upon clathrin knockdown. Nef localizes preferentially to AP-1 tubules in cells, explaining how Nef sequesters MHC-I. Coat contact residues are conserved across Arf isoforms and the Arf-dependent AP complexes AP-1, AP-3, and AP-4. Thus, AP complexes can self-assemble with Arf1 into tubular coats without clathrin or other scaffolding factors. The AP-1:Arf1 coat defines the structural basis of a broader class of tubulovesicular membrane coats as an intermediate in clathrin vesicle formation from internal membranes and as an MHC-I sequestration mechanism in HIV-1 infection.
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Affiliation(s)
- Richard M. Hooy
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
- California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Yuichiro Iwamoto
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
- California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Dan A. Tudorica
- California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, CA 94720, USA
- Graduate Group in Biophysics, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Xuefeng Ren
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
- California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, CA 94720, USA
| | - James H. Hurley
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
- California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, CA 94720, USA
- Graduate Group in Biophysics, University of California, Berkeley, Berkeley, CA 94720, USA
- Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA 94720, USA
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9
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Zhao F, Xu F, Liu X, Hu Y, Wei L, Fan Z, Wang L, Huang Y, Mei S, Guo L, Yang L, Cen S, Wang J, Liang C, Guo F. SERINC5 restricts influenza virus infectivity. PLoS Pathog 2022; 18:e1010907. [PMID: 36223419 PMCID: PMC9591065 DOI: 10.1371/journal.ppat.1010907] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Revised: 10/24/2022] [Accepted: 09/30/2022] [Indexed: 11/16/2022] Open
Abstract
SERINC5 is a multi-span transmembrane protein that is incorporated into HIV-1 particles in producing cells and inhibits HIV-1 entry. Multiple retroviruses like HIV-1, equine infectious anemia virus and murine leukemia virus are subject to SERINC5 inhibition, while HIV-1 pseudotyped with envelope glycoproteins of vesicular stomatitis virus and Ebola virus are resistant to SERINC5. The antiviral spectrum and the underlying mechanisms of SERINC5 restriction are not completely understood. Here we show that SERINC5 inhibits influenza A virus infection by targeting virus-cell membrane fusion at an early step of infection. Further results show that different influenza hemagglutinin (HA) subtypes exhibit diverse sensitivities to SERINC5 restriction. Analysis of the amino acid sequences of influenza HA1 strains indicates that HA glycosylation sites correlate with the sensitivity of influenza HA to SERINC5, and the inhibitory effect of SERINC5 was lost when certain HA glycosylation sites were mutated. Our study not only expands the antiviral spectrum of SERINC5, but also reveals the role of viral envelope glycosylation in resisting SERINC5 restriction.
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Affiliation(s)
- Fei Zhao
- NHC Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, and Center for AIDS Research, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, P. R. China
| | - Fengwen Xu
- NHC Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, and Center for AIDS Research, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, P. R. China
| | - Xiaoman Liu
- NHC Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, and Center for AIDS Research, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, P. R. China
| | - Yamei Hu
- NHC Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, and Center for AIDS Research, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, P. R. China
| | - Liang Wei
- NHC Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, and Center for AIDS Research, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, P. R. China
| | - Zhangling Fan
- NHC Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, and Center for AIDS Research, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, P. R. China
| | - Liming Wang
- NHC Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, and Center for AIDS Research, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, P. R. China
| | - Yu Huang
- NHC Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, and Center for AIDS Research, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, P. R. China
| | - Shan Mei
- NHC Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, and Center for AIDS Research, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, P. R. China
| | - Li Guo
- NHC Key Laboratory of Systems Biology of Pathogens and Christophe Mérieux Laboratory, Institute of Pathogen Biology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, P. R. China
| | - Long Yang
- School of Integrative Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Shan Cen
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, P. R. China
| | - Jianwei Wang
- NHC Key Laboratory of Systems Biology of Pathogens and Christophe Mérieux Laboratory, Institute of Pathogen Biology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, P. R. China
- * E-mail: (JW); (CL); (FG)
| | - Chen Liang
- McGill University AIDS Centre, Lady Davis Institute, Jewish General Hospital, Montreal, Quebec, Canada
- * E-mail: (JW); (CL); (FG)
| | - Fei Guo
- NHC Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, and Center for AIDS Research, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, P. R. China
- * E-mail: (JW); (CL); (FG)
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10
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Structure of HIV-1 Vpr in complex with the human nucleotide excision repair protein hHR23A. Nat Commun 2021; 12:6864. [PMID: 34824204 PMCID: PMC8617076 DOI: 10.1038/s41467-021-27009-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Accepted: 10/26/2021] [Indexed: 11/25/2022] Open
Abstract
HIV-1 Vpr is a prototypic member of a large family of structurally related lentiviral virulence factors that antagonize various aspects of innate antiviral immunity. It subverts host cell DNA repair and protein degradation machineries by binding and inhibiting specific post-replication repair enzymes, linking them via the DCAF1 substrate adaptor to the Cullin 4 RING E3 ligase (CRL4DCAF1). HIV-1 Vpr also binds to the multi-domain protein hHR23A, which interacts with the nucleotide excision repair protein XPC and shuttles ubiquitinated proteins to the proteasome. Here, we report the atomic resolution structure of Vpr in complex with the C-terminal half of hHR23A, containing the XPC-binding (XPCB) and ubiquitin-associated (UBA2) domains. The XPCB and UBA2 domains bind to different sides of Vpr's 3-helix-bundle structure, with UBA2 interacting with the α2 and α3 helices of Vpr, while the XPCB domain contacts the opposite side of Vpr's α3 helix. The structure as well as biochemical results reveal that hHR23A and DCAF1 use overlapping binding surfaces on Vpr, even though the two proteins exhibit entirely different three-dimensional structures. Our findings show that Vpr independently targets hHR23A- and DCAF1- dependent pathways and highlight HIV-1 Vpr as a versatile module that interferes with DNA repair and protein degradation pathways.
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11
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Ali A, Kumar V, Banerjea AC. STUB1/CHIP promotes ubiquitination and degradation of HIV-1 Vif to restore the cellular level of APOBEC3G protein. Biochem Biophys Res Commun 2021; 574:27-32. [PMID: 34425283 DOI: 10.1016/j.bbrc.2021.08.031] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Accepted: 08/09/2021] [Indexed: 10/20/2022]
Abstract
HIV-1 accessory protein Vif is required for neutralization of cellular restriction factor APOBEC3G through its ubiquitination and proteasomal degradation which allows replication of HIV-1 in non-permissive cells. This function of Vif is required for maintaining the genomic integrity of HIV-1. We here report that the Vif interacts with the cellular E3 ubiquitin ligase CHIP and the level of Vif protein gets reduced by the expression of CHIP. Reduction of Vif by CHIP expression is due to its increased rate of degradation as shown by cycloheximide (CHX) chase assay. CHIP expression also resulted in the ubiquitination of Vif protein in a dose dependent manner. The role of CHIP in the ubiquitination and degradation was confirmed by the endogenous knockdown of CHIP using CRISPR Cas9 method. Loss of endogenous CHIP protein showed the stabilization of Vif with concomitant destabilization of APOBEC3G. As expected Vif mediated ubiquitination of APOBEC3G was also reduced in CHIP knockdown cells. These results established that CHIP functions as a negative regulator of Vif protein which in-turn stabilizes APOBEC3G.
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Affiliation(s)
- Amjad Ali
- Laboratory of Virology, National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi, 110067, India; Department of Molecular, Cell and Cancer Biology, University of Massachusetts Medical School, Worcester, MA, 01605, USA.
| | - Vivek Kumar
- Laboratory of Virology, National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi, 110067, India
| | - Akhil C Banerjea
- Laboratory of Virology, National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi, 110067, India.
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Hendricks CM, Cordeiro T, Gomes AP, Stevenson M. The Interplay of HIV-1 and Macrophages in Viral Persistence. Front Microbiol 2021; 12:646447. [PMID: 33897659 PMCID: PMC8058371 DOI: 10.3389/fmicb.2021.646447] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2020] [Accepted: 03/11/2021] [Indexed: 12/18/2022] Open
Abstract
HIV-1 has evolved mechanisms to evade host cell immune responses and persist for lifelong infection. Latent cellular reservoirs are responsible for this persistence of HIV-1 despite the powerful effects of highly active antiretroviral therapies (HAART) to control circulating viral load. While cellular reservoirs have been extensively studied, much of these studies have focused on peripheral blood and resting memory CD4+ T cells containing latent HIV-1 provirus; however, efforts to eradicate cellular reservoirs have been stunted by reservoirs found in tissues compartments that are not easily accessible. These tissues contain resting memory CD4+ T cells and tissue resident macrophages, another latent cellular reservoir to HIV-1. Tissue resident macrophages have been associated with HIV-1 infection since the 1980s, and evidence has continued to grow regarding their role in HIV-1 persistence. Specific biological characteristics play a vital role as to why macrophages are latent cellular reservoirs for HIV-1, and in vitro and in vivo studies exhibit how macrophages contribute to viral persistence in individuals and animals on antiretroviral therapies. In this review, we characterize the role and evolutionary advantages of macrophage reservoirs to HIV-1 and their contribution to HIV-1 persistence. In acknowledging the interplay of HIV-1 and macrophages in the host, we identify reasons why current strategies are incapable of eliminating HIV-1 reservoirs and why efforts must focus on eradicating reservoirs to find a future functional cure.
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Affiliation(s)
- Chynna M Hendricks
- Department of Microbiology & Immunology, Miller School of Medicine, University of Miami, Miami, FL, United States
| | - Thaissa Cordeiro
- Department of Medicine, Miller School of Medicine, University of Miami, Miami, FL, United States
| | - Ana Paula Gomes
- Department of Medicine, Miller School of Medicine, University of Miami, Miami, FL, United States
| | - Mario Stevenson
- Department of Medicine, Miller School of Medicine, University of Miami, Miami, FL, United States
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13
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Zhou X, Monnie C, DeLucia M, Ahn J. HIV-1 Vpr activates host CRL4-DCAF1 E3 ligase to degrade histone deacetylase SIRT7. Virol J 2021; 18:48. [PMID: 33648539 PMCID: PMC7923639 DOI: 10.1186/s12985-021-01514-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Accepted: 02/12/2021] [Indexed: 12/05/2022] Open
Abstract
Background Vpr is a virion-associated protein that is encoded by lentiviruses and serves to counteract intrinsic immunity factors that restrict infection. HIV-1 Vpr mediates proteasome-dependent degradation of several DNA repair/modification proteins. Mechanistically, Vpr directly recruits cellular targets onto DCAF1, a substrate receptor of Cullin 4 RING E3 ubiquitin ligase (CRL4) for poly-ubiquitination. Further, Vpr can mediate poly-ubiquitination of DCAF1-interacting proteins by the CRL4. Because Vpr-mediated degradation of its known targets can not explain the primary cell-cycle arrest phenotype that Vpr expression induces, we surveyed the literature for DNA-repair-associated proteins that interact with the CRL4-DCAF1. One such protein is SIRT7, a deacetylase of histone 3 that belongs to the Sirtuin family and regulates a wide range of cellular processes. We wondered whether Vpr can mediate degradation of SIRT7 via the CRL4-DCAF1. Methods HEK293T cells were transfected with cocktails of plasmids expressing DCAF1, DDB1, SIRT7 and Vpr. Ectopic and endogeneous levels of SIRT7 were monitered by immunoblotting and protein–protein interactions were assessed by immunoprecipitation. For in vitro reconstitution assays, recombinant CRL4-DCAF1-Vpr complexes and SIRT7 were prepared and poly-ubiqutination of SIRT7 was monitored with immunoblotting. Results We demonstrate SIRT7 polyubiquitination and degradation upon Vpr expression. Specifically, SIRT7 is shown to interact with the CRL4-DCAF1 complex, and expression of Vpr in HEK293T cells results in SIRT7 degradation, which is partially rescued by CRL inhibitor MNL4924 and proteasome inhibitor MG132. Further, in vitro reconstitution assays show that Vpr induces poly-ubiquitination of SIRT7 by the CRL4-DCAF1. Importantly, we find that Vpr from several different HIV-1 strains, but not HIV-2 strains, mediates SIRT7 poly-ubiquitination in the reconstitution assay and degradation in cells. Finally, we show that SIRT7 degradation by Vpr is independent of the known, distinctive phenotype of Vpr-induced cell cycle arrest at the G2 phase, Conclusions Targeting histone deacetylase SIRT7 for degradation is a conserved feature of HIV-1 Vpr. Altogether, our findings reveal that HIV-1 Vpr mediates down-regulation of SIRT7 by a mechanism that does not involve novel target recruitment to the CRL4-DCAF1 but instead involves regulation of the E3 ligase activity.
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Affiliation(s)
- Xiaohong Zhou
- Department of Structural Biology and Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh School of Medicine, Biomedical Science Tower 3, RM 1055, 3501 Fifth Ave., Pittsburgh, PA, 15260, USA
| | - Christina Monnie
- Department of Structural Biology and Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh School of Medicine, Biomedical Science Tower 3, RM 1055, 3501 Fifth Ave., Pittsburgh, PA, 15260, USA
| | - Maria DeLucia
- Department of Structural Biology and Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh School of Medicine, Biomedical Science Tower 3, RM 1055, 3501 Fifth Ave., Pittsburgh, PA, 15260, USA
| | - Jinwoo Ahn
- Department of Structural Biology and Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh School of Medicine, Biomedical Science Tower 3, RM 1055, 3501 Fifth Ave., Pittsburgh, PA, 15260, USA.
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14
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McNamara RP, Dittmer DP. Extracellular vesicles in virus infection and pathogenesis. Curr Opin Virol 2020; 44:129-138. [PMID: 32846272 PMCID: PMC7755726 DOI: 10.1016/j.coviro.2020.07.014] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Revised: 07/18/2020] [Accepted: 07/20/2020] [Indexed: 12/11/2022]
Abstract
Viruses are obligate intracellular parasites that usurp cellular signaling networks to promote pathogen spread and disease progression. Signaling through extracellular vesicles (EVs) is an emerging field of study in the virus-host interaction network. EVs relay information both locally and distally through incorporated contents, typically without tripping innate immune sensors. Therefore, this extracellular signaling axis presents itself as a tantalizing target for promoting a favorable niche for the pathogen(s) takeover of the host, particularly for chronic infections. From the incorporation of virus-encoded molecules such as micro RNAs and proteins/enzymes to the envelopment of entire infectious particles, evolutionary distinct viruses have shown a remarkable ability to converge on this means of communication. In this review, we will cover the recent advances in this field and explore how EV can be used as potential biomarkers for chronic, persistent, or latent virus infections.
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Affiliation(s)
- Ryan P McNamara
- Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC 27599, United States; Department of Microbiology and Immunology, The University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC 27599, United States
| | - Dirk P Dittmer
- Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC 27599, United States; Department of Microbiology and Immunology, The University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC 27599, United States.
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15
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Ali A, Farooqui SR, Rai J, Singh J, Kumar V, Mishra R, Banerjea AC. HIV-1 Nef promotes ubiquitination and proteasomal degradation of p53 tumor suppressor protein by using E6AP. Biochem Biophys Res Commun 2020; 529:1038-1044. [PMID: 32819562 DOI: 10.1016/j.bbrc.2020.05.188] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Accepted: 05/25/2020] [Indexed: 01/19/2023]
Abstract
Human Immunodeficiency Virus-1 (HIV-1) Nef promotes p53 protein degradation to protect HIV-1 infected cells from p53 induced apoptosis. We found that Nef mediated p53 degradation is accomplished through ubiquitin proteasome pathway in an Mdm2-independent manner. By GST pulldown and immunoprecipitation assays, we have shown that Nef interacts with E3 ubiquitin ligase E6AP in both Nef transfected HEK-293T cells and HIV-1 infected MOLT3 cells. The p53 ubiquitination and degradation was found to be enhanced by Nef with E6AP but not by Nef with E6AP-C843A, a dominant negative E6AP mutant. We show that Nef binds with E6AP and promotes E6AP dependent p53 ubiquitination. Further, Nef inhibits apoptosis of p53 null H1299 cells after exogenous expression of p53 protein. The p53 dependent apoptosis of H1299 cells was further reduced after the expression of Nef with E6AP. However, Nef mediated reduction in p53 induced apoptosis of H1299 cells was restored when Nef was co-expressed with E6AP-C843A. Thus, Nef and E6AP co-operate to promote p53 ubiquitination and degradation in order to suppress p53 dependent apoptosis. CHME3 cells, which are a natural host of HIV-1, also show p53 ubiquitination and degradation by Nef and E6AP. These results establish that Nef induces p53 degradation via cellular E3 ligase E6AP to inhibit apoptosis during HIV-1 infection.
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Affiliation(s)
- Amjad Ali
- Virology Lab, National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi, 110067, India; Department of Molecular, Cell and Cancer Biology, University of Massachusetts Medical School, Worcester, MA, USA 01605.
| | - Sabihur Rahman Farooqui
- Virology Lab, National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi, 110067, India.
| | - Jagdish Rai
- IFSC, Panjab University, Chandigarh, 160014, India.
| | - Jyotsna Singh
- Virology Lab, National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi, 110067, India.
| | - Vivek Kumar
- Virology Lab, National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi, 110067, India.
| | - Ritu Mishra
- Virology Lab, National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi, 110067, India.
| | - Akhil C Banerjea
- Virology Lab, National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi, 110067, India.
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16
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He L, Chen X, Yang J, Zhang T, Li J, Zhang S, Zhong K, Zhang H, Chen J, Yang J. Rice black-streaked dwarf virus-encoded P5-1 regulates the ubiquitination activity of SCF E3 ligases and inhibits jasmonate signaling to benefit its infection in rice. THE NEW PHYTOLOGIST 2020; 225:896-912. [PMID: 31318448 PMCID: PMC6972624 DOI: 10.1111/nph.16066] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Accepted: 07/09/2019] [Indexed: 05/29/2023]
Abstract
SCF (Skp1/Cullin1/F-box) complexes are key regulators of many cellular processes. Viruses encode specific factors to interfere with or hijack these complexes and ensure their infection in plants. The molecular mechanisms controlling this interference/hijack are currently largely unknown. Here, we present evidence of a novel strategy used by Rice black-streaked dwarf virus (RBSDV) to regulate ubiquitination in rice (Oryza sativa) by interfering in the activity of OsCSN5A. We also show that RBSDV P5-1 specifically affects CSN-mediated deRUBylation of OsCUL1, compromising the integrity of the SCFCOI1 complex. We demonstrate that the expressions of jasmonate (JA) biosynthesis-associated genes are not inhibited, whereas the expressions of JA-responsive genes are down-regulated in transgenic P5-1 plants. More importantly, application of JA to P5-1 transgenic plants did not reduce their susceptibility to RBSDV infection. Our results suggest that P5-1 inhibits the ubiquitination activity of SCF E3 ligases through an interaction with OsCSN5A, and hinders the RUBylation/deRUBylation of CUL1, leading to an inhibition of the JA response pathway and an enhancement of RBSDV infection in rice.
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Affiliation(s)
- Long He
- State Key Laboratory for Quality and Safety of Agro‐productsInstitute of Plant VirologyNingbo UniversityNingbo315000China
- State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Zhejiang Provincial Key Laboratory of Plant VirologyInstitute of Virology and Biotechnology, Zhejiang Academy of Agricultural SciencesHangzhou310021China
- College of Plant ProtectionNanjing Agricultural UniversityNanjing21000China
| | - Xuan Chen
- State Key Laboratory for Quality and Safety of Agro‐productsInstitute of Plant VirologyNingbo UniversityNingbo315000China
| | - Jin Yang
- State Key Laboratory for Quality and Safety of Agro‐productsInstitute of Plant VirologyNingbo UniversityNingbo315000China
- College of Plant ProtectionHunan Agricultural UniversityChangsha410000China
| | - Tianye Zhang
- State Key Laboratory for Quality and Safety of Agro‐productsInstitute of Plant VirologyNingbo UniversityNingbo315000China
- College of Forestry and BiotechnologyZhejiang A&F UniversityLinan311300China
| | - Juan Li
- State Key Laboratory for Quality and Safety of Agro‐productsInstitute of Plant VirologyNingbo UniversityNingbo315000China
- College of Agriculture and BiotechnologyZhejiang UniversityHangzhou310058China
| | - Songbai Zhang
- Institute of Plant ProtectionHunan Academy of Agricultural SciencesChangsha410000China
| | - Kaili Zhong
- State Key Laboratory for Quality and Safety of Agro‐productsInstitute of Plant VirologyNingbo UniversityNingbo315000China
| | - Hengmu Zhang
- State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Zhejiang Provincial Key Laboratory of Plant VirologyInstitute of Virology and Biotechnology, Zhejiang Academy of Agricultural SciencesHangzhou310021China
| | - Jianping Chen
- State Key Laboratory for Quality and Safety of Agro‐productsInstitute of Plant VirologyNingbo UniversityNingbo315000China
| | - Jian Yang
- State Key Laboratory for Quality and Safety of Agro‐productsInstitute of Plant VirologyNingbo UniversityNingbo315000China
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17
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Liu Y, Tan X. Viral Manipulations of the Cullin-RING Ubiquitin Ligases. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1217:99-110. [PMID: 31898224 DOI: 10.1007/978-981-15-1025-0_7] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Cullin-RING ubiquitin ligases (CRLs) are efficient and diverse toolsets of the cells to regulate almost every biological process. However, these characteristics have also been usurped by many viruses to optimize for their replication. CRLs are often at the forefront of the arms races in the coevolution of viruses and hosts. Here we review the modes of actions and functional consequences of viral manipulations of host cell CRLs. We also discuss the therapeutic applications to target these viral manipulations for treating viral infections.
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Affiliation(s)
- Ying Liu
- MOE Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology, Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structures, School of Pharmaceutical Sciences, Tsinghua University, Beijing, China
| | - Xu Tan
- MOE Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology, Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structures, School of Pharmaceutical Sciences, Tsinghua University, Beijing, China.
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18
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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.
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19
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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.
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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.
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20
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Lentiviral Vpx induces alteration of mammalian cell nuclear envelope integrity. Biochem Biophys Res Commun 2019; 511:192-198. [PMID: 30777327 DOI: 10.1016/j.bbrc.2019.02.018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2019] [Accepted: 02/03/2019] [Indexed: 11/23/2022]
Abstract
Vpx, a virion-associated protein of Human Immunodeficiency Virus 2 (HIV-2) and Simian Immunodeficiency Virus (SIV) counteracts host restriction factor SAMDH1 for efficient viral DNA synthesis in the cytoplasm and mediates subsequent nuclear translocation of the viral genome. Vpx was found to be indispensable in the viral infection of terminally differentiated target cells and macaques infected with virions carrying truncated Vpx showed delayed pathogenesis, suggesting multiple roles of Vpx at different steps in the virus life cycle. The current study demonstrates a novel function of SIVsmPBj1.9 Vpx on the integrity of the nuclear envelope in HeLa cells. Results from the Super-Resolution Structured Illumination Microscopy (SR-SIM) analysis showed that Vpx puncta alter HeLa cell nuclear envelope assembly. Furthermore, three-dimensional (3D) SIM analysis of such regions suggests that Vpx is primed in a specific way to disrupt the nuclear envelope integrity. The nuclear incursion of cytoplasmic proteins through Vpx mediated ruptured nuclear envelope regions suggest that these events might play a critical role in the nuclear entry of otherwise cytoplasmically sequestered molecules and theirby may be assisting Vpx functions including the transport of viral genome into the nucleus, which is critical for the establishment of virus infection and pathogenesis.
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21
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Naidoo L, Mzobe Z, Jin SW, Rajkoomar E, Reddy T, Brockman MA, Brumme ZL, Ndung'u T, Mann JK. Nef-mediated inhibition of NFAT following TCR stimulation differs between HIV-1 subtypes. Virology 2019; 531:192-202. [PMID: 30927712 DOI: 10.1016/j.virol.2019.02.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Revised: 02/13/2019] [Accepted: 02/16/2019] [Indexed: 01/11/2023]
Abstract
Functional characterisation of different HIV-1 subtypes may improve understanding of viral pathogenesis and spread. Here, we evaluated the ability of 345 unique HIV-1 Nef clones representing subtypes A, B, C and D to inhibit NFAT signalling following TCR stimulation. The contribution of this Nef function to disease progression was also assessed in 211 additional Nef clones isolated from unique subtype C infected individuals in early or chronic infection. On average, subtype A and C Nef clones exhibited significantly lower ability to inhibit TCR-mediated NFAT signalling compared to subtype B and D Nef clones. While this observation corroborates accumulating evidence supporting relative attenuation of subtypes A and C that may paradoxically contribute to their increased global prevalence and spread, no significant correlations between Nef-mediated NFAT inhibition activity and clinical markers of HIV-1 infection were observed, indicating that the relationship between Nef function and pathogenesis is complex.
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Affiliation(s)
- Lisa Naidoo
- HIV Pathogenesis Programme, University of KwaZulu-Natal, Durban 4001, South Africa
| | - Zinhle Mzobe
- HIV Pathogenesis Programme, University of KwaZulu-Natal, Durban 4001, South Africa
| | - Steven W Jin
- Faculty of Health Sciences, Simon Fraser University, Burnaby, BC, Canada V5A 1S6
| | - Erasha Rajkoomar
- HIV Pathogenesis Programme, University of KwaZulu-Natal, Durban 4001, South Africa
| | - Tarylee Reddy
- Medical Research Council, Biostatistics Unit, Durban 4001, South Africa
| | - Mark A Brockman
- Faculty of Health Sciences, Simon Fraser University, Burnaby, BC, Canada V5A 1S6; Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, BC, Canada V5A 1S6; British Columbia Centre for Excellence in HIV/AIDS, Vancouver, BC, Canada V6Z 1Y6
| | - Zabrina L Brumme
- Faculty of Health Sciences, Simon Fraser University, Burnaby, BC, Canada V5A 1S6; British Columbia Centre for Excellence in HIV/AIDS, Vancouver, BC, Canada V6Z 1Y6
| | - Thumbi Ndung'u
- HIV Pathogenesis Programme, University of KwaZulu-Natal, Durban 4001, South Africa; Ragon Institute of Massachusetts General Hospital, Massachusetts Institute of Technology and Harvard University, Cambridge, MA, USA; Africa Health Research Institute, Durban 4001, South Africa; Max Planck Institute for Infection Biology, Chariteplatz, D-10117 Berlin, Germany
| | - Jaclyn K Mann
- HIV Pathogenesis Programme, University of KwaZulu-Natal, Durban 4001, South Africa.
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22
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Davoodi S, Bolhassani A, Sadat SM, Irani S. Enhancing HIV-1 Nef Penetration into Mammalian Cells as an Antigen Candidate. JOURNAL OF MEDICAL MICROBIOLOGY AND INFECTIOUS DISEASES 2019. [DOI: 10.29252/jommid.7.1.2.37] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
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23
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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.
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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.
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24
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Identification of Novel Subcellular Localization and Trafficking of HIV-1 Nef Variants from Reference Strains G (F1.93.HH8793) and H (BE.93.VI997). Viruses 2018; 10:v10090493. [PMID: 30217018 PMCID: PMC6164931 DOI: 10.3390/v10090493] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Revised: 08/30/2018] [Accepted: 09/11/2018] [Indexed: 11/17/2022] Open
Abstract
The human immunodeficiency virus type 1 (HIV-1) accessory protein Nef, plays an essential role in disease progression and pathogenesis via hijacking the host cellular membrane-trafficking machinery. Interestingly, HIV-1 group-M subtypes display differences in the rate of disease progression. However, few reports investigated how the cellular behaviors and activities of Nef isolates from reference strains may differ between HIV-1 group-M subtypes. Here, we characterize how differing cellular distributions of Nef proteins across group-M subtypes may impact protein function using immunofluorescence microscopy and flow cytometric analysis. We demonstrate that Nef variants isolated from HIV-1 group-M subtypes display differences in expression, with low expressing Nef proteins from reference strains of subtypes G (F1.93.HH8793) and H (BE.93.VI997) also displaying decreased functionality. Additionally, we demonstrate variations in the subcellular distribution and localization of these Nef proteins. Nef from subtype G (F1.93.HH8793) and H (BE.93.VI997) reference strains also failed to colocalize with the trans-Golgi network, and were not differentially localized to cellular markers of multivesicular bodies or lysosomes. Strikingly, our results demonstrate that HIV-1 Nef proteins from reference strains G (F1.93.HH8793) and H (BE.93.VI997) highly colocalize with labeled mitochondrial compartments.
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Abstract
Impressive advances have been made in the treatment and management of HIV-1 infected individuals. Combination antiretroviral therapy (cART) has turned HIV-1 infection from an almost invariable deadly infectious disease, to a lifelong manageable infectious disease. However, a cure or vaccine has not been forthcoming. A major problem in HIV-1 infection is the persistent and latently infected cellular and tissue reservoirs. One of these reservoirs is the Gut Associated Lymphoid tissue (GALT), which has been the research focus of our group. Our group and others have shown that HIV-1 evolves differently in different parts of the gastro intestinal tract, which also appears to affect the development of antiretroviral drug resistance. The GALT is not the only reservoir. HIV-1 continues to persist and evolve in various other cell and tissue reservoirs despite intense and apparent successful antiretroviral therapy. Moreover, drug resistance mutations remain prevalent under therapy and successful viral suppression. In addition to finding a vaccine, the research on combating and eradicating the HIV-1 viral reservoirs has also been an important focus of HIV-1 cure strategies. We will discuss some of the research findings on reservoirs in the context of some of the HIV-1 cure approaches.
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Affiliation(s)
- Guido van Marle
- a Department of Microbiology Immunology and Infectious Diseases, Cumming School of Medicine , University of Calgary , Calgary , Canada
| | - Deirdre L Church
- b Department of Medicine, Cumming School of Medicine , University of Calgary , Calgary , Canada.,c Department of Pathology and Laboratory Medicine, Cumming School of Medicine , University of Calgary , Calgary , Canada
| | - Frank van der Meer
- d Faculty of Veterinary Medicine, Department of Ecosystem and Public Health , University of Calgary , Calgary , Canada
| | - M John Gill
- a Department of Microbiology Immunology and Infectious Diseases, Cumming School of Medicine , University of Calgary , Calgary , Canada.,b Department of Medicine, Cumming School of Medicine , University of Calgary , Calgary , Canada
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Sauter D, Kirchhoff F. Multilayered and versatile inhibition of cellular antiviral factors by HIV and SIV accessory proteins. Cytokine Growth Factor Rev 2018. [PMID: 29526437 DOI: 10.1016/j.cytogfr.2018.02.005] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
HIV-1, the main causative agent of AIDS, and related primate lentiviruses show a striking ability to efficiently replicate throughout the lifetime of an infected host. In addition to their high variability, the acquisition of several accessory genes has enabled these viruses to efficiently evade or counteract seemingly strong antiviral immune responses. The respective viral proteins, i.e. Vif, Vpr, Vpu, Vpx and Nef, show a stunning functional diversity, acting by various mechanisms and targeting a large variety of cellular factors involved in innate and adaptive immunity. A focus of the present review is the accumulating evidence that Vpr, Vpu and Nef not only directly target cellular antiviral factors at the protein level, but also suppress their expression by modulating the activity of immune-regulatory transcription factors such as NF-κB. Furthermore, we will discuss the ability of accessory proteins to act as versatile adaptors, removing antiviral proteins from their sites of action and/or targeting them for proteasomal or endolysosomal degradation. Here, the main emphasis will be on emerging examples for functional interactions, synergisms and switches between accessory primate lentiviral proteins. A better understanding of this complex interplay between cellular immune defense mechanisms and viral countermeasures might facilitate the development of effective vaccines, help to prevent harmful chronic inflammation, and provide insights into the establishment and maintenance of latent viral reservoirs.
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Affiliation(s)
- Daniel Sauter
- Institute of Molecular Virology, Ulm University Medical Center, Meyerhofstr. 1, 89081 Ulm, Germany.
| | - Frank Kirchhoff
- Institute of Molecular Virology, Ulm University Medical Center, Meyerhofstr. 1, 89081 Ulm, Germany.
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Franchini AM, Lawrence BP. Environmental exposures are hidden modifiers of anti-viral immunity. CURRENT OPINION IN TOXICOLOGY 2018; 10:54-59. [PMID: 30035244 DOI: 10.1016/j.cotox.2018.01.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Significant advances have been made recent years elucidating antiviral immune mechanisms that protect the host from viral infection. Similarly, our understanding of how viruses bind, enter, and replicate within host cells has continued to grow. Yet, viruses continue to take a toll on human health. The influence of chemicals in the environment is among key factors that influence outcomes of viral infection. There is a growing appreciation of the effects that exogenous environmental chemical exposures have on the immune system and antiviral immunity. Epidemiological studies have linked a variety of chemical exposures to poorer health, increased incidence of infection, and worsened vaccine responses. However, the mechanisms that govern these associations are not well understood, limiting our ability to predict or mitigate the effects of environmental exposures on public health. This brief review focuses on recent advances in the field, highlighting novel in vitro and in vivo findings informed by past foundational studies. Furthermore, current information suggests avenues of investigation that have yet to be explored, but which will significantly impact on our understanding about how environmental exposures impact viral defenses, vaccine efficacy, and the spread of contemporary and emerging viral pathogens.
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Affiliation(s)
- Anthony M Franchini
- Department of Environmental Medicine, University of Rochester School of Medicine & Dentistry, Rochester, NY 14642 USA
| | - B Paige Lawrence
- Department of Environmental Medicine, University of Rochester School of Medicine & Dentistry, Rochester, NY 14642 USA
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Olgun HB, Tasyurek HM, Sanlioglu AD, Sanlioglu S. High-Titer Production of HIV-Based Lentiviral Vectors in Roller Bottles for Gene and Cell Therapy. Methods Mol Biol 2018; 1879:323-345. [PMID: 29797007 DOI: 10.1007/7651_2018_150] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Lentiviral vectors are becoming preferred vectors of choice for clinical gene therapy trials due to their safety, efficacy, and the long-term gene expression they provide. Although the efficacy of lentiviral vectors is mainly predetermined by the therapeutic genes they carry, they must be produced at high titers to exert therapeutic benefit for in vivo applications. Thus, there is need for practical, robust, and scalable viral vector production methods applicable to any laboratory setting. Here, we describe a practical lentiviral production technique in roller bottles yielding high-titer third-generation lentiviral vectors useful for in vivo gene transfer applications. CaPO4-mediated transient transfection protocol involving the use of a transfer vector and three different packaging plasmids is employed to generate lentivectors in roller bottles. Following clearance of cellular debris via low-speed centrifugation and filtration, virus is concentrated by high-speed ultracentrifugation over sucrose cushion.
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Affiliation(s)
- Hazal Banu Olgun
- Human Gene and Cell Therapy Center of Akdeniz University Hospitals, Antalya, Turkey
| | - Hale M Tasyurek
- Human Gene and Cell Therapy Center of Akdeniz University Hospitals, Antalya, Turkey
| | | | - Salih Sanlioglu
- Human Gene and Cell Therapy Center of Akdeniz University Hospitals, Antalya, Turkey.
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Hölzemer A, Garcia-Beltran WF, Altfeld M. Natural Killer Cell Interactions with Classical and Non-Classical Human Leukocyte Antigen Class I in HIV-1 Infection. Front Immunol 2017; 8:1496. [PMID: 29184550 PMCID: PMC5694438 DOI: 10.3389/fimmu.2017.01496] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Accepted: 10/24/2017] [Indexed: 11/23/2022] Open
Abstract
Natural killer (NK) cells are effector lymphocytes of the innate immune system that are able to mount a multifaceted antiviral response within hours following infection. This is achieved through an array of cell surface receptors surveilling host cells for alterations in human leukocyte antigen class I (HLA-I) expression and other ligands as signs of viral infection, malignant transformation, and cellular stress. This interaction between HLA-I ligands and NK-cell receptor is not only important for recognition of diseased cells but also mediates tuning of NK-cell-effector functions. HIV-1 alters the expression of HLA-I ligands on infected cells, rendering them susceptible to NK cell-mediated killing. However, over the past years, various HIV-1 evasion strategies have been discovered to target NK-cell-receptor ligands and allow the virus to escape from NK cell-mediated immunity. While studies have been mainly focusing on the role of polymorphic HLA-A, -B, and -C molecules, less is known about how HIV-1 affects the more conserved, non-classical HLA-I molecules HLA-E, -G, and -F. In this review, we will focus on the recent progress in understanding the role of non-classical HLA-I ligands in NK cell-mediated recognition of HIV-1-infected cells.
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Affiliation(s)
- Angelique Hölzemer
- First Department of Internal Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- German Center for Infection Research (DZIF), Partner site Hamburg-Lübeck-Borstel-Riems, Hamburg, Germany
| | | | - Marcus Altfeld
- German Center for Infection Research (DZIF), Partner site Hamburg-Lübeck-Borstel-Riems, Hamburg, Germany
- Institute for Immunology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
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Zhou X, DeLucia M, Hao C, Hrecka K, Monnie C, Skowronski J, Ahn J. HIV-1 Vpr protein directly loads helicase-like transcription factor (HLTF) onto the CRL4-DCAF1 E3 ubiquitin ligase. J Biol Chem 2017; 292:21117-21127. [PMID: 29079575 DOI: 10.1074/jbc.m117.798801] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Revised: 10/23/2017] [Indexed: 11/06/2022] Open
Abstract
The viral protein R (Vpr) is an accessory virulence factor of HIV-1 that facilitates infection in immune cells. Cellular functions of Vpr are tied to its interaction with DCAF1, a substrate receptor component of the CRL4 E3 ubiquitin ligase. Recent proteomic approaches suggested that Vpr degrades helicase-like transcription factor (HLTF) DNA helicase in a proteasome-dependent manner by redirecting the CRL4-DCAF1 E3 ligase. However, the precise molecular mechanism of Vpr-dependent HLTF depletion is not known. Here, using in vitro reconstitution assays, we show that Vpr mediates polyubiquitination of HLTF, by directly loading it onto the C-terminal WD40 domain of DCAF1 in complex with the CRL4 E3 ubiquitin ligase. Mutational analyses suggest that Vpr interacts with DNA-binding residues in the N-terminal HIRAN domain of HLTF in a manner similar to the recruitment of another target, uracil DNA glycosylase (UNG2), to the CRL4-DCAF1 E3 by Vpr. Strikingly, Vpr also engages a second, adjacent region, which connects the HIRAN and ATPase/helicase domains. Thus, our findings reveal that Vpr utilizes common as well as distinctive interfaces to recruit multiple postreplication DNA repair proteins to the CRL4-DCAF1 E3 ligase for ubiquitin-dependent proteasomal degradation.
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Affiliation(s)
- Xiaohong Zhou
- From the Department of Structural Biology and Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15260 and
| | - Maria DeLucia
- From the Department of Structural Biology and Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15260 and
| | - Caili Hao
- Department of Molecular Biology and Microbiology, Case Western Reserve School of Medicine, Cleveland, Ohio 44106
| | - Kasia Hrecka
- Department of Molecular Biology and Microbiology, Case Western Reserve School of Medicine, Cleveland, Ohio 44106
| | - Christina Monnie
- From the Department of Structural Biology and Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15260 and
| | - Jacek Skowronski
- Department of Molecular Biology and Microbiology, Case Western Reserve School of Medicine, Cleveland, Ohio 44106
| | - Jinwoo Ahn
- From the Department of Structural Biology and Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15260 and
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Bennett M, Tu SL, Upton C, McArtor C, Gillett A, Laird T, O’Dea M. Complete genomic characterisation of two novel poxviruses (WKPV and EKPV) from western and eastern grey kangaroos. Virus Res 2017; 242:106-121. [DOI: 10.1016/j.virusres.2017.09.016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Revised: 09/23/2017] [Accepted: 09/25/2017] [Indexed: 10/18/2022]
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Chen S, Yang X, Cheng W, Ma Y, Shang Y, Cao L, Chen S, Chen Y, Wang M, Guo D. Immune regulator ABIN1 suppresses HIV-1 transcription by negatively regulating the ubiquitination of Tat. Retrovirology 2017; 14:12. [PMID: 28193275 PMCID: PMC5304394 DOI: 10.1186/s12977-017-0338-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Accepted: 01/31/2017] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND A20-binding inhibitor of NF-κB activation (ABIN1), an important immune regulator, was previously shown to be involved in HIV-1 replication. However, the reported studies done with overexpressed ABIN1 provided controversial results. RESULTS Here we identified ABIN1 as a suppressor of HIV-1 transcription since transient knockdown of ABIN1 led to increased HIV-1 replication both in transformed Jurkat T cell line and in primary human CD4+ T lymphocytes. Depletion of ABIN1 specifically enhanced the HIV-1 transcription from the integrated genome during viral life cycle, but not the earlier steps such as reverse transcription or integration. Immunoprecipitation assays revealed that ABIN1 specifically inhibits the proto-oncogene HDM2 catalyzed K63-linked polyubiquitination of Tat at Lys71, which is critical for the transactivation activity of Tat. The ubiquitin chain binding activity of ABIN1 carried by UBAN domain turned out to be essential for the inhibitory role of ABIN1. The results of immunofluorescence localization experiments suggested that ABIN1 may obstruct Tat ubiquitination by redistributing some of HDM2 from the nucleus to the cytoplasm. CONCLUSIONS Our findings have revealed ABIN1 as intrinsic suppressor of HIV-1 mRNA transcription by regulating the ubiquitination of Tat.
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Affiliation(s)
- Shiyou Chen
- State Key Laboratory of Virology and Modern Virology Research Center, College of Life Sciences, Wuhan University, Wuhan, 430072, People's Republic of China
| | - Xiaodan Yang
- State Key Laboratory of Virology and Modern Virology Research Center, College of Life Sciences, Wuhan University, Wuhan, 430072, People's Republic of China
| | - Weijia Cheng
- Clinical Laboratory, General Hospital of the Yangtze River Shipping, Wuhan, 430010, People's Republic of China
| | - Yuhong Ma
- School of Basic Medical Sciences, Wuhan University, Wuhan, 430071, People's Republic of China
| | - Yafang Shang
- State Key Laboratory of Virology and Modern Virology Research Center, College of Life Sciences, Wuhan University, Wuhan, 430072, People's Republic of China
| | - Liu Cao
- State Key Laboratory of Virology and Modern Virology Research Center, College of Life Sciences, Wuhan University, Wuhan, 430072, People's Republic of China
| | - Shuliang Chen
- School of Basic Medical Sciences, Wuhan University, Wuhan, 430071, People's Republic of China
| | - Yu Chen
- State Key Laboratory of Virology and Modern Virology Research Center, College of Life Sciences, Wuhan University, Wuhan, 430072, People's Republic of China
| | - Min Wang
- School of Basic Medical Sciences, Wuhan University, Wuhan, 430071, People's Republic of China.
| | - Deyin Guo
- State Key Laboratory of Virology and Modern Virology Research Center, College of Life Sciences, Wuhan University, Wuhan, 430072, People's Republic of China. .,School of Basic Medical Sciences, Wuhan University, Wuhan, 430071, People's Republic of China. .,School of Basic Medicine (Shenzhen), Sun Yat-sen University, Guangzhou, 510080, People's Republic of China.
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HIV-1 Nef sequesters MHC-I intracellularly by targeting early stages of endocytosis and recycling. Sci Rep 2016; 6:37021. [PMID: 27841315 PMCID: PMC5107982 DOI: 10.1038/srep37021] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Accepted: 10/24/2016] [Indexed: 11/25/2022] Open
Abstract
A defining characteristic of HIV-1 infection is the ability of the virus to persist within the host. Specifically, MHC-I downregulation by the HIV-1 accessory protein Nef is of critical importance in preventing infected cells from cytotoxic T-cell mediated killing. Nef downregulates MHC-I by modulating the host membrane trafficking machinery, resulting in the endocytosis and eventual sequestration of MHC-I within the cell. In the current report, we utilized the intracellular protein-protein interaction reporter system, bimolecular fluorescence complementation (BiFC), in combination with super-resolution microscopy, to track the Nef/MHC-I interaction and determine its subcellular localization in cells. We demonstrate that this interaction occurs upon Nef binding the MHC-I cytoplasmic tail early during endocytosis in a Rab5-positive endosome. Disruption of early endosome regulation inhibited Nef-dependent MHC-I downregulation, demonstrating that Nef hijacks the early endosome to sequester MHC-I within the cell. Furthermore, super-resolution imaging identified that the Nef:MHC-I BiFC complex transits through both early and late endosomes before ultimately residing at the trans-Golgi network. Together we demonstrate the importance of the early stages of the endocytic network in the removal of MHC-I from the cell surface and its re-localization within the cell, which allows HIV-1 to optimally evade host immune responses.
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Abstract
Retrotransposons have generated about 40 % of the human genome. This review examines the strategies the cell has evolved to coexist with these genomic "parasites", focussing on the non-long terminal repeat retrotransposons of humans and mice. Some of the restriction factors for retrotransposition, including the APOBECs, MOV10, RNASEL, SAMHD1, TREX1, and ZAP, also limit replication of retroviruses, including HIV, and are part of the intrinsic immune system of the cell. Many of these proteins act in the cytoplasm to degrade retroelement RNA or inhibit its translation. Some factors act in the nucleus and involve DNA repair enzymes or epigenetic processes of DNA methylation and histone modification. RISC and piRNA pathway proteins protect the germline. Retrotransposon control is relaxed in some cell types, such as neurons in the brain, stem cells, and in certain types of disease and cancer, with implications for human health and disease. This review also considers potential pitfalls in interpreting retrotransposon-related data, as well as issues to consider for future research.
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Affiliation(s)
- John L. Goodier
- McKusick-Nathans Institute for Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD USA 212051
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Rotavirus NSP1 Associates with Components of the Cullin RING Ligase Family of E3 Ubiquitin Ligases. J Virol 2016; 90:6036-48. [PMID: 27099313 DOI: 10.1128/jvi.00704-16] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Accepted: 04/15/2016] [Indexed: 12/17/2022] Open
Abstract
UNLABELLED The rotavirus nonstructural protein NSP1 acts as an antagonist of the host antiviral response by inducing degradation of key proteins required to activate interferon (IFN) production. Protein degradation induced by NSP1 is dependent on the proteasome, and the presence of a RING domain near the N terminus has led to the hypothesis that NSP1 is an E3 ubiquitin ligase. To examine this hypothesis, pulldown assays were performed, followed by mass spectrometry to identify components of the host ubiquitination machinery that associate with NSP1. Multiple components of cullin RING ligases (CRLs), which are essential multisubunit ubiquitination complexes, were identified in association with NSP1. The mass spectrometry was validated in both transfected and infected cells to show that the NSP1 proteins from different strains of rotavirus associated with key components of CRL complexes, most notably the cullin scaffolding proteins Cul3 and Cul1. In vitro binding assays using purified proteins confirmed that NSP1 specifically interacted with Cul3 and that the N-terminal region of Cul3 was responsible for binding to NSP1. To test if NSP1 used CRL3 to induce degradation of the target protein IRF3 or β-TrCP, Cul3 levels were knocked down using a small interfering RNA (siRNA) approach. Unexpectedly, loss of Cul3 did not rescue IRF3 or β-TrCP from degradation in infected cells. The results indicate that, rather than actively using CRL complexes to induce degradation of target proteins required for IFN production, NSP1 may use cullin-containing complexes to prevent another cellular activity. IMPORTANCE The ubiquitin-proteasome pathway plays an important regulatory role in numerous cellular functions, and many viruses have evolved mechanisms to exploit or manipulate this pathway to enhance replication and spread. Rotavirus, a major cause of severe gastroenteritis in young children that causes approximately 420,000 deaths worldwide each year, utilizes the ubiquitin-proteasome system to subvert the host innate immune response by inducing the degradation of key components required for the production of interferon (IFN). Here, we show that NSP1 proteins from different rotavirus strains associate with the scaffolding proteins Cul1 and Cul3 of CRL ubiquitin ligase complexes. Nonetheless, knockdown of Cul1 and Cul3 suggests that NSP1 induces the degradation of some target proteins independently of its association with CRL complexes, stressing a need to further investigate the mechanistic details of how NSP1 subverts the host IFN response.
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Poltronieri P, Sun B, Mallardo M. RNA Viruses: RNA Roles in Pathogenesis, Coreplication and Viral Load. Curr Genomics 2016; 16:327-35. [PMID: 27047253 PMCID: PMC4763971 DOI: 10.2174/1389202916666150707160613] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2015] [Revised: 04/10/2015] [Accepted: 04/14/2015] [Indexed: 01/30/2023] Open
Abstract
The review intends to present and recapitulate the current knowledge on the roles and importance of regulatory RNAs, such as microRNAs and small interfering RNAs, RNA binding proteins and enzymes processing RNAs or activated by RNAs, in cells infected by RNA viruses. The review focuses on how non-coding RNAs are involved in RNA virus replication, pathogenesis and host response, especially in retroviruses HIV, with examples of the mechanisms of action, transcriptional regulation, and promotion of increased stability of their targets or their degradation.
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Affiliation(s)
- Palmiro Poltronieri
- CNR-ISPA, Institute of Sciences of Food Productions, National Research Council of Italy, Lecce, Italy
| | - Binlian Sun
- Research Group of HIV Molecular Epidemiology and Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, Hubei 430071, PR China
| | - Massimo Mallardo
- Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II°, Napoli, Italy
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Shen QT, Ren X, Zhang R, Lee IH, Hurley JH. HIV-1 Nef hijacks clathrin coats by stabilizing AP-1:Arf1 polygons. Science 2016; 350:aac5137. [PMID: 26494761 DOI: 10.1126/science.aac5137] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The lentiviruses HIV and simian immunodeficiency virus (SIV) subvert intracellular membrane traffic as part of their replication cycle. The lentiviral Nef protein helps viruses evade innate and adaptive immune defenses by hijacking the adaptor protein 1 (AP-1) and AP-2 clathrin adaptors. We found that HIV-1 Nef and the guanosine triphosphatase Arf1 induced trimerization and activation of AP-1. Here we report the cryo-electron microscopy structures of the Nef- and Arf1-bound AP-1 trimer in the active and inactive states. A central nucleus of three Arf1 molecules organizes the trimers. We combined the open trimer with a known dimer structure and thus predicted a hexagonal assembly with inner and outer faces that bind the membranes and clathrin, respectively. Hexagons were directly visualized and the model validated by reconstituting clathrin cage assembly. Arf1 and Nef thus play interconnected roles in allosteric activation, cargo recruitment, and coat assembly, revealing an unexpectedly intricate organization of the inner AP-1 layer of the clathrin coat.
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Affiliation(s)
- Qing-Tao Shen
- Department of Molecular and Cell Biology and California Institute for Quantitative Biosciences, University of California, Berkeley, 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
| | - Rui Zhang
- Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Il-Hyung Lee
- 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. Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
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Sobhy H. A Review of Functional Motifs Utilized by Viruses. Proteomes 2016; 4:proteomes4010003. [PMID: 28248213 PMCID: PMC5217368 DOI: 10.3390/proteomes4010003] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Revised: 01/07/2016] [Accepted: 01/13/2016] [Indexed: 01/05/2023] Open
Abstract
Short linear motifs (SLiM) are short peptides that facilitate protein function and protein-protein interactions. Viruses utilize these motifs to enter into the host, interact with cellular proteins, or egress from host cells. Studying functional motifs may help to predict protein characteristics, interactions, or the putative cellular role of a protein. In virology, it may reveal aspects of the virus tropism and help find antiviral therapeutics. This review highlights the recent understanding of functional motifs utilized by viruses. Special attention was paid to the function of proteins harboring these motifs, and viruses encoding these proteins. The review highlights motifs involved in (i) immune response and post-translational modifications (e.g., ubiquitylation, SUMOylation or ISGylation); (ii) virus-host cell interactions, including virus attachment, entry, fusion, egress and nuclear trafficking; (iii) virulence and antiviral activities; (iv) virion structure; and (v) low-complexity regions (LCRs) or motifs enriched with residues (Xaa-rich motifs).
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Affiliation(s)
- Haitham Sobhy
- Department of Molecular Biology, Umeå University, 901 87 Umeå, Sweden.
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Induction of Heme Oxygenase-1 Deficiency and Associated Glutamate-Mediated Neurotoxicity Is a Highly Conserved HIV Phenotype of Chronic Macrophage Infection That Is Resistant to Antiretroviral Therapy. J Virol 2015; 89:10656-67. [PMID: 26269184 DOI: 10.1128/jvi.01495-15] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Accepted: 08/05/2015] [Indexed: 01/09/2023] Open
Abstract
UNLABELLED Expression of the cytoprotective enzyme heme oxygenase-1 (HO-1) is significantly reduced in the brain prefrontal cortex of HIV-positive individuals with HIV-associated neurocognitive disorders (HAND). Furthermore, this HO-1 deficiency correlates with brain viral load, markers of macrophage activation, and type I interferon responses. In vitro, HIV replication in monocyte-derived macrophages (MDM) selectively reduces HO-1 protein and RNA expression and induces production of neurotoxic levels of glutamate; correction of this HO-1 deficiency reduces neurotoxic glutamate production without an effect on HIV replication. We now demonstrate that macrophage HO-1 deficiency, and the associated neurotoxin production, is a conserved feature of infection with macrophage-tropic HIV-1 strains that correlates closely with the extent of replication, and this feature extends to HIV-2 infection. We further demonstrate that this HO-1 deficiency does not depend specifically upon the HIV-1 accessory genes nef, vpr, or vpu but rather on HIV replication, even when markedly limited. Finally, antiretroviral therapy (ART) applied to MDM after HIV infection is established does not prevent HO-1 loss or the associated neurotoxin production. This work defines a predictable relationship between HIV replication, HO-1 loss, and neurotoxin production in MDM that likely reflects processes in place in the HIV-infected brains of individuals receiving ART. It further suggests that correcting this HO-1 deficiency in HIV-infected MDM could provide neuroprotection above that provided by current ART or proposed antiviral therapies directed at limiting Nef, Vpr, or Vpu functions. The ability of HIV-2 to reduce HO-1 expression suggests that this is a conserved phenotype among macrophage-tropic human immunodeficiency viruses that could contribute to neuropathogenesis. IMPORTANCE The continued prevalence of HIV-associated neurocognitive disorders (HAND) underscores the need for adjunctive therapy that targets the neuropathological processes that persist in antiretroviral therapy (ART)-treated HIV-infected individuals. To this end, we previously identified one such possible process, a deficiency of the antioxidative and anti-inflammatory enzyme heme oxygenase-1 (HO-1) in the brains of individuals with HAND. In the present study, our findings suggest that the HO-1 deficiency associated with excess glutamate production and neurotoxicity in HIV-infected macrophages is a highly conserved phenotype of macrophage-tropic HIV strains and that this phenotype can persist in the macrophage compartment in the presence of ART. This suggests a plausible mechanism by which HIV infection of brain macrophages in ART-treated individuals could exacerbate oxidative stress and glutamate-induced neuronal injury, each of which is associated with neurocognitive dysfunction in infected individuals. Thus, therapies that rescue the HO-1 deficiency in HIV-infected individuals could provide additional neuroprotection to ART.
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Raghavan M, Geng J. HLA-B polymorphisms and intracellular assembly modes. Mol Immunol 2015; 68:89-93. [PMID: 26239417 DOI: 10.1016/j.molimm.2015.07.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Revised: 06/29/2015] [Accepted: 07/07/2015] [Indexed: 02/08/2023]
Abstract
Human leukocyte antigen (HLA) class I molecules are ligands for antigen receptors of cytotoxic T cells (CTL) and inhibitory receptors of natural killer (NK) cells. The high degree of HLA class I polymorphism allows for the selection of distinct and diverse sets of antigenic peptide ligands for presentation to CTL. The extensive polymorphisms of the HLA class I genes also result in large variations in their intracellular folding and assembly characteristics. Recent findings indicate that North American HLA-B variants differ significantly in the stabilities of their peptide-deficient forms and in the requirements for the endoplasmic reticulum (ER)-resident factor tapasin for proper assembly. In HIV-infected individuals, the presence of tapasin-independent HLA-B allotypes links to more rapid progression to death. Further studies are important to better understand how the intrinsic structural characteristics of HLA class I folding intermediates affect immune responses mediated by CTL and NK cells.
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Affiliation(s)
- Malini Raghavan
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109, USA.
| | - Jie Geng
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
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Collins DR, Lubow J, Lukic Z, Mashiba M, Collins KL. Vpr Promotes Macrophage-Dependent HIV-1 Infection of CD4+ T Lymphocytes. PLoS Pathog 2015; 11:e1005054. [PMID: 26186441 PMCID: PMC4506080 DOI: 10.1371/journal.ppat.1005054] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Accepted: 06/29/2015] [Indexed: 11/18/2022] Open
Abstract
Vpr is a conserved primate lentiviral protein that promotes infection of T lymphocytes in vivo by an unknown mechanism. Here we demonstrate that Vpr and its cellular co-factor, DCAF1, are necessary for efficient cell-to-cell spread of HIV-1 from macrophages to CD4+ T lymphocytes when there is inadequate cell-free virus to support direct T lymphocyte infection. Remarkably, Vpr functioned to counteract a macrophage-specific intrinsic antiviral pathway that targeted Env-containing virions to LAMP1+ lysosomal compartments. This restriction of Env also impaired virological synapses formed through interactions between HIV-1 Env on infected macrophages and CD4 on T lymphocytes. Treatment of infected macrophages with exogenous interferon-alpha induced virion degradation and blocked synapse formation, overcoming the effects of Vpr. These results provide a mechanism that helps explain the in vivo requirement for Vpr and suggests that a macrophage-dependent stage of HIV-1 infection drives the evolutionary conservation of Vpr.
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Affiliation(s)
- David R. Collins
- Department of Microbiology & Immunology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Jay Lubow
- Department of Microbiology & Immunology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Zana Lukic
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Michael Mashiba
- Medical Scientist Training Program, University of Michigan, Ann Arbor, Michigan, United States of America
- Graduate Program in Immunology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Kathleen L. Collins
- Department of Microbiology & Immunology, University of Michigan, Ann Arbor, Michigan, United States of America
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, United States of America
- Medical Scientist Training Program, University of Michigan, Ann Arbor, Michigan, United States of America
- Graduate Program in Immunology, University of Michigan, Ann Arbor, Michigan, United States of America
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Involvement of a C-terminal motif in the interference of primate lentiviral Vpu proteins with CD1d-mediated antigen presentation. Sci Rep 2015; 5:9675. [PMID: 25872908 PMCID: PMC4397644 DOI: 10.1038/srep09675] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2014] [Accepted: 03/16/2015] [Indexed: 01/01/2023] Open
Abstract
The HIV-1 accessory protein Vpu is emerging as a critical factor for viral evasion from innate immunity. We have previously shown that the Vpu proteins of two HIV-1 group M subtype B strains (NL4-3 and BaL) down-regulate CD1d from the surface of infected dendritic cells (DCs) and inhibit their crosstalk with the innate invariant natural killer T (iNKT) cells. In the present study, we have investigated the ability of a comprehensive set of primate lentiviral Vpu proteins to interfere with CD1d-mediated immunity. We found that CD1d down-regulation is a conserved function of Vpu proteins from HIV-1 groups M, O and P as well as their direct precursors SIVcpzPtt and SIVgor. At the group M subtype level, subtype C Vpu proteins were significantly weaker CD1d antagonists than subtype B Vpu proteins. Functional characterization of different mutants and chimeras derived from active subtype B and inactive subtype C Vpu proteins revealed that residues in the cytoplasmic domain are important for CD1d down-regulation. Specifically, we identified a C-terminal APW motif characteristic for group M subtype B Vpu proteins necessary for interference with CD1d surface expression. These findings support the notion that Vpu plays an important role in lentiviral evasion from innate immunity.
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Boso G, Somia NV. Characterization of resistance to rhabdovirus and retrovirus infection in a human myeloid cell line. PLoS One 2015; 10:e0121455. [PMID: 25811758 PMCID: PMC4374779 DOI: 10.1371/journal.pone.0121455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Accepted: 02/13/2015] [Indexed: 11/30/2022] Open
Abstract
Viruses interact with various permissive and restrictive factors in host cells throughout their replication cycle. Cell lines that are non-permissive to viral infection have been particularly useful in discovering host cell proteins involved in viral life cycles. Here we describe the characterization of a human myeloid leukemia cell line, KG-1, that is resistant to infection by retroviruses and a Rhabdovirus. We show that KG-1 cells are resistant to infection by Vesicular Stomatits Virus as well as VSV Glycoprotein (VSVG) pseudotyped retroviruses due to a defect in binding. Moreover our results indicate that entry by xenotropic retroviral envelope glycoprotein RD114 is impaired in KG-1 cells. Finally we characterize a post- entry block in the early phase of the retroviral life cycle in KG-1 cells that renders the cell line refractory to infection. This cell line will have utility in discovering proteins involved in infection by VSV and HIV-1.
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Affiliation(s)
- Guney Boso
- Molecular, Cellular, Developmental Biology and Genetics Graduate Program, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Nikunj V. Somia
- Dept. of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, Minnesota, United States of America
- * E-mail:
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Mashiba M, Collins DR, Terry VH, Collins KL. Vpr overcomes macrophage-specific restriction of HIV-1 Env expression and virion production. Cell Host Microbe 2014; 16:722-35. [PMID: 25464830 PMCID: PMC4269377 DOI: 10.1016/j.chom.2014.10.014] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2014] [Revised: 07/21/2014] [Accepted: 10/06/2014] [Indexed: 12/30/2022]
Abstract
The HIV-1 accessory protein Vpr enhances infection of primary macrophages through unknown mechanisms. Recent studies demonstrated that Vpr interactions with the cellular DCAF1-DDB1-CUL4 E3 ubiquitin ligase complex limit activation of innate immunity and interferon (IFN) induction. We describe a restriction mechanism that targets the HIV-1 envelope protein Env, but is overcome by Vpr and its interaction with DCAF1. This restriction is active in the absence of Vpr in HIV-1-infected primary macrophages and macrophage-epithelial cell heterokaryons, but not epithelial cell lines. HIV-1-infected macrophages lacking Vpr express more IFN following infection, target Env for lysosomal degradation, and produce fewer Env-containing virions. Conversely, Vpr expression reduces IFN induction, rescues Env expression, and enhances virion release. Addition of IFN or silencing DCAF1 reduces the amount of cell-associated Env and virion production in wild-type HIV-1-infected primary macrophages. These findings provide insight into an IFN-stimulated macrophage-specific restriction pathway targeting HIV-1 Env that is counteracted by Vpr.
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Affiliation(s)
- Michael Mashiba
- Graduate Program in Immunology, University of Michigan, Ann Arbor, MI 48109, USA; Medical Scientist Training Program, University of Michigan, Ann Arbor, MI 48109, USA
| | - David R Collins
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Valeri H Terry
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48109, USA
| | - Kathleen L Collins
- Graduate Program in Immunology, University of Michigan, Ann Arbor, MI 48109, USA; Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI 48109, USA; Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48109, USA.
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Choi SB, Choong YS, Saito A, Wahab HA, Najimudin N, Watanabe N, Osada H, Ong EBB. In Silico Investigation of a HIV-1 Vpr Inhibitor Binding Site: Potential for Virtual Screening and anti-HIV Drug Design. Mol Inform 2014; 33:742-8. [DOI: 10.1002/minf.201400080] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Accepted: 10/15/2014] [Indexed: 11/06/2022]
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Cullin E3 ligases and their rewiring by viral factors. Biomolecules 2014; 4:897-930. [PMID: 25314029 PMCID: PMC4279162 DOI: 10.3390/biom4040897] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2014] [Revised: 08/20/2014] [Accepted: 09/15/2014] [Indexed: 02/06/2023] Open
Abstract
The ability of viruses to subvert host pathways is central in disease pathogenesis. Over the past decade, a critical role for the Ubiquitin Proteasome System (UPS) in counteracting host immune factors during viral infection has emerged. This counteraction is commonly achieved by the expression of viral proteins capable of sequestering host ubiquitin E3 ligases and their regulators. In particular, many viruses hijack members of the Cullin-RING E3 Ligase (CRL) family. Viruses interact in many ways with CRLs in order to impact their ligase activity; one key recurring interaction involves re-directing CRL complexes to degrade host targets that are otherwise not degraded within host cells. Removal of host immune factors by this mechanism creates a more amenable cellular environment for viral propagation. To date, a small number of target host factors have been identified, many of which are degraded via a CRL-proteasome pathway. Substantial effort within the field is ongoing to uncover the identities of further host proteins targeted in this fashion and the underlying mechanisms driving their turnover by the UPS. Elucidation of these targets and mechanisms will provide appealing anti-viral therapeutic opportunities. This review is focused on the many methods used by viruses to perturb host CRLs, focusing on substrate sequestration and viral regulation of E3 activity.
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Chanzu N, Ondondo B. Induction of Potent and Long-Lived Antibody and Cellular Immune Responses in the Genitorectal Mucosa Could be the Critical Determinant of HIV Vaccine Efficacy. Front Immunol 2014; 5:202. [PMID: 24847327 PMCID: PMC4021115 DOI: 10.3389/fimmu.2014.00202] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Accepted: 04/23/2014] [Indexed: 01/28/2023] Open
Abstract
The field of HIV prevention has indeed progressed in leaps and bounds, but with major limitations of the current prevention and treatment options, the world remains desperate for an HIV vaccine. Sadly, this continues to be elusive, because more than 30 years since its discovery there is no licensed HIV vaccine. Research aiming to define immunological biomarkers to accurately predict vaccine efficacy have focused mainly on systemic immune responses, and as such, studies defining correlates of protection in the genitorectal mucosa, the primary target site for HIV entry and seeding are sparse. Clearly, difficulties in sampling and analysis of mucosal specimens, as well as their limited size have been a major deterrent in characterizing the type (mucosal antibodies, cytokines, chemokines, or CTL), threshold (magnitude, depth, and breadth) and viral inhibitory capacity of HIV-1-specific immune responses in the genitorectal mucosa, where they are needed to immediately block HIV acquisition and arrest subsequent virus dissemination. Nevertheless, a few studies document the existence of HIV-specific immune responses in the genitorectal mucosa of HIV-infected aviremic and viremic controllers, as well as in highly exposed persistently seronegative (HEPS) individuals with natural resistance to HIV-1. Some of these responses strongly correlate with protection from HIV acquisition and/or disease progression, thus providing significant clues of the ideal components of an efficacious HIV vaccine. In this study, we provide an overview of the key features of protective immune responses found in HEPS, elite and viremic controllers, and discuss how these can be achieved through mucosal immunization. Inevitably, HIV vaccine development research will have to consider strategies that elicit potent antibody and cellular immune responses within the genitorectal mucosa or induction of systemic immune cells with an inherent potential to home and persist at mucosal sites of HIV entry.
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Affiliation(s)
- Nadia Chanzu
- Institute of Tropical and Infectious Diseases, College of Health Sciences, University of Nairobi , Nairobi , Kenya
| | - Beatrice Ondondo
- The Jenner Institute, Nuffield Department of Medicine, University of Oxford , Oxford , UK
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