1
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Vanegas-Torres CA, Schindler M. HIV-1 Vpr Functions in Primary CD4 + T Cells. Viruses 2024; 16:420. [PMID: 38543785 PMCID: PMC10975730 DOI: 10.3390/v16030420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Revised: 03/05/2024] [Accepted: 03/05/2024] [Indexed: 05/23/2024] Open
Abstract
HIV-1 encodes four accesory proteins in addition to its structural and regulatory genes. Uniquely amongst them, Vpr is abundantly present within virions, meaning it is poised to exert various biological effects on the host cell upon delivery. In this way, Vpr contributes towards the establishment of a successful infection, as evidenced by the extent to which HIV-1 depends on this factor to achieve full pathogenicity in vivo. Although HIV infects various cell types in the host organism, CD4+ T cells are preferentially targeted since they are highly permissive towards productive infection, concomitantly bringing about the hallmark immune dysfunction that accompanies HIV-1 spread. The last several decades have seen unprecedented progress in unraveling the activities Vpr possesses in the host cell at the molecular scale, increasingly underscoring the importance of this viral component. Nevertheless, it remains controversial whether some of these advances bear in vivo relevance, since commonly employed cellular models significantly differ from primary T lymphocytes. One prominent example is the "established" ability of Vpr to induce G2 cell cycle arrest, with enigmatic physiological relevance in infected primary T lymphocytes. The objective of this review is to present these discoveries in their biological context to illustrate the mechanisms whereby Vpr supports HIV-1 infection in CD4+ T cells, whilst identifying findings that require validation in physiologically relevant models.
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Affiliation(s)
| | - Michael Schindler
- Institute for Medical Virology and Epidemiology of Viral Diseases, University Hospital Tuebingen, 72076 Tuebingen, Germany;
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2
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Woottum M, Yan S, Sayettat S, Grinberg S, Cathelin D, Bekaddour N, Herbeuval JP, Benichou S. Macrophages: Key Cellular Players in HIV Infection and Pathogenesis. Viruses 2024; 16:288. [PMID: 38400063 PMCID: PMC10893316 DOI: 10.3390/v16020288] [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: 01/22/2024] [Revised: 02/12/2024] [Accepted: 02/13/2024] [Indexed: 02/25/2024] Open
Abstract
Although cells of the myeloid lineages, including tissue macrophages and conventional dendritic cells, were rapidly recognized, in addition to CD4+ T lymphocytes, as target cells of HIV-1, their specific roles in the pathophysiology of infection were initially largely neglected. However, numerous studies performed over the past decade, both in vitro in cell culture systems and in vivo in monkey and humanized mouse animal models, led to growing evidence that macrophages play important direct and indirect roles as HIV-1 target cells and in pathogenesis. It has been recently proposed that macrophages are likely involved in all stages of HIV-1 pathogenesis, including virus transmission and dissemination, but above all, in viral persistence through the establishment, together with latently infected CD4+ T cells, of virus reservoirs in many host tissues, the major obstacle to virus eradication in people living with HIV. Infected macrophages are indeed found, very often as multinucleated giant cells expressing viral antigens, in almost all lymphoid and non-lymphoid tissues of HIV-1-infected patients, where they can probably persist for long period of time. In addition, macrophages also likely participate, directly as HIV-1 targets or indirectly as key regulators of innate immunity and inflammation, in the chronic inflammation and associated clinical disorders observed in people living with HIV, even in patients receiving effective antiretroviral therapy. The main objective of this review is therefore to summarize the recent findings, and also to revisit older data, regarding the critical functions of tissue macrophages in the pathophysiology of HIV-1 infection, both as major HIV-1-infected target cells likely found in almost all tissues, as well as regulators of innate immunity and inflammation during the different stages of HIV-1 pathogenesis.
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Affiliation(s)
- Marie Woottum
- Institut Cochin, Inserm U1016, CNRS UMR-8104, Université Paris Cité, 75014 Paris, France; (M.W.); (S.Y.); (S.S.)
| | - Sen Yan
- Institut Cochin, Inserm U1016, CNRS UMR-8104, Université Paris Cité, 75014 Paris, France; (M.W.); (S.Y.); (S.S.)
| | - Sophie Sayettat
- Institut Cochin, Inserm U1016, CNRS UMR-8104, Université Paris Cité, 75014 Paris, France; (M.W.); (S.Y.); (S.S.)
| | - Séverine Grinberg
- CNRS UMR-8601, Université Paris Cité, 75006 Paris, France; (S.G.); (D.C.); (N.B.); (J.-P.H.)
| | - Dominique Cathelin
- CNRS UMR-8601, Université Paris Cité, 75006 Paris, France; (S.G.); (D.C.); (N.B.); (J.-P.H.)
| | - Nassima Bekaddour
- CNRS UMR-8601, Université Paris Cité, 75006 Paris, France; (S.G.); (D.C.); (N.B.); (J.-P.H.)
| | - Jean-Philippe Herbeuval
- CNRS UMR-8601, Université Paris Cité, 75006 Paris, France; (S.G.); (D.C.); (N.B.); (J.-P.H.)
| | - Serge Benichou
- Institut Cochin, Inserm U1016, CNRS UMR-8104, Université Paris Cité, 75014 Paris, France; (M.W.); (S.Y.); (S.S.)
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3
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Muselmani W, Kashif-Khan N, Bagnéris C, Santangelo R, Williams MA, Savva R. A Multimodal Approach towards Genomic Identification of Protein Inhibitors of Uracil-DNA Glycosylase. Viruses 2023; 15:1348. [PMID: 37376646 DOI: 10.3390/v15061348] [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: 04/14/2023] [Revised: 06/02/2023] [Accepted: 06/06/2023] [Indexed: 06/29/2023] Open
Abstract
DNA-mimicking proteins encoded by viruses can modulate processes such as innate cellular immunity. An example is Ung-family uracil-DNA glycosylase inhibition, which prevents Ung-mediated degradation via the stoichiometric protein blockade of the Ung DNA-binding cleft. This is significant where uracil-DNA is a key determinant in the replication and distribution of virus genomes. Unrelated protein folds support a common physicochemical spatial strategy for Ung inhibition, characterised by pronounced sequence plasticity within the diverse fold families. That, and the fact that relatively few template sequences are biochemically verified to encode Ung inhibitor proteins, presents a barrier to the straightforward identification of Ung inhibitors in genomic sequences. In this study, distant homologs of known Ung inhibitors were characterised via structural biology and structure prediction methods. A recombinant cellular survival assay and in vitro biochemical assay were used to screen distant variants and mutants to further explore tolerated sequence plasticity in motifs supporting Ung inhibition. The resulting validated sequence repertoire defines an expanded set of heuristic sequence and biophysical signatures shared by known Ung inhibitor proteins. A computational search of genome database sequences and the results of recombinant tests of selected output sequences obtained are presented here.
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Affiliation(s)
- Wael Muselmani
- Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck, University of London, Malet Street, London WC1E 7HX, UK
| | - Naail Kashif-Khan
- Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck, University of London, Malet Street, London WC1E 7HX, UK
| | - Claire Bagnéris
- Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck, University of London, Malet Street, London WC1E 7HX, UK
| | - Rosalia Santangelo
- Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck, University of London, Malet Street, London WC1E 7HX, UK
| | - Mark A Williams
- Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck, University of London, Malet Street, London WC1E 7HX, UK
| | - Renos Savva
- Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck, University of London, Malet Street, London WC1E 7HX, UK
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4
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Diatlova EA, Mechetin GV, Yudkina AV, Zharkov VD, Torgasheva NA, Endutkin AV, Shulenina OV, Konevega AL, Gileva IP, Shchelkunov SN, Zharkov DO. Correlated Target Search by Vaccinia Virus Uracil-DNA Glycosylase, a DNA Repair Enzyme and a Processivity Factor of Viral Replication Machinery. Int J Mol Sci 2023; 24:ijms24119113. [PMID: 37298065 DOI: 10.3390/ijms24119113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 05/13/2023] [Accepted: 05/21/2023] [Indexed: 06/12/2023] Open
Abstract
The protein encoded by the vaccinia virus D4R gene has base excision repair uracil-DNA N-glycosylase (vvUNG) activity and also acts as a processivity factor in the viral replication complex. The use of a protein unlike PolN/PCNA sliding clamps is a unique feature of orthopoxviral replication, providing an attractive target for drug design. However, the intrinsic processivity of vvUNG has never been estimated, leaving open the question whether it is sufficient to impart processivity to the viral polymerase. Here, we use the correlated cleavage assay to characterize the translocation of vvUNG along DNA between two uracil residues. The salt dependence of the correlated cleavage, together with the similar affinity of vvUNG for damaged and undamaged DNA, support the one-dimensional diffusion mechanism of lesion search. Unlike short gaps, covalent adducts partly block vvUNG translocation. Kinetic experiments show that once a lesion is found it is excised with a probability ~0.76. Varying the distance between two uracils, we use a random walk model to estimate the mean number of steps per association with DNA at ~4200, which is consistent with vvUNG playing a role as a processivity factor. Finally, we show that inhibitors carrying a tetrahydro-2,4,6-trioxopyrimidinylidene moiety can suppress the processivity of vvUNG.
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Affiliation(s)
- Evgeniia A Diatlova
- SB RAS Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Ave., 630090 Novosibirsk, Russia
| | - Grigory V Mechetin
- SB RAS Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Ave., 630090 Novosibirsk, Russia
| | - Anna V Yudkina
- SB RAS Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Ave., 630090 Novosibirsk, Russia
| | - Vasily D Zharkov
- Biology Department, Tomsk State University, 634050 Tomsk, Russia
| | - Natalia A Torgasheva
- SB RAS Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Ave., 630090 Novosibirsk, Russia
| | - Anton V Endutkin
- SB RAS Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Ave., 630090 Novosibirsk, Russia
| | - Olga V Shulenina
- NRC "Kurchatov Institute"-B. P. Konstantinov Petersburg Nuclear Physics Institute, Leningrad Region, 188300 Gatchina, Russia
| | - Andrey L Konevega
- NRC "Kurchatov Institute"-B. P. Konstantinov Petersburg Nuclear Physics Institute, Leningrad Region, 188300 Gatchina, Russia
| | - Irina P Gileva
- State Research Center of Virology and Biotechnology Vector, Novosibirsk Region, 630559 Koltsovo, Russia
| | - Sergei N Shchelkunov
- State Research Center of Virology and Biotechnology Vector, Novosibirsk Region, 630559 Koltsovo, Russia
| | - Dmitry O Zharkov
- SB RAS Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Ave., 630090 Novosibirsk, Russia
- Department of Natural Sciences, Novosibirsk State University, 2 Pirogova St., 630090 Novosibirsk, Russia
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5
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Ruhanya V, Jacobs GB, Paul RH, Joska JA, Seedat S, Nyandoro G, Glashoff RH, Engelbrecht S. HIV-1 Subtype C Vpr Amino Acid Residue 45Y and Specific Conserved Fragments Are Associated with Neurocognitive Impairment and Markers of Viral Load. AIDS Res Hum Retroviruses 2023; 39:166-175. [PMID: 36401355 DOI: 10.1089/aid.2022.0022] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
There is increasing evidence that HIV-1 viral protein R (Vpr) plays an important role in the pathogenesis of cognitive impairment. We investigated the relationship between HIV-1 subtype C Vpr sequence variation and HIV-associated neurocognitive impairment as measured by global deficit score (GDS) in treatment-naive individuals. We used different bioinformatic tools and statistical models to correlate vpr variation and cognitive function. We identified a tyrosine at position 45 (45Y) as a signature for neurocognitive impairment and histidine (45H) as a signature in the non-impaired individuals. The presence of signature 45Y was associated by 3.66 times higher GDS, 525 times higher plasma viral load, 15.84 times higher proviral load, and 60% lower absolute CD4-T cell count compared with those without the signature. Additionally, we identified four conserved Vpr fragment sequences, PEDQGPQREPYNEWTLE (5-21), LGQYIY (42-47), TYGDTW (49-54), and PEDQGPQREPYNEW (5-18), that were associated with higher plasma viral load and proviral load. The implication of these findings is that variation of Vpr leads to neurocognitive impairment in HIV infection and worsens the progression of disease in general by promoting the production of provirus, promoting HIV replication and depletion of CD4+ T cells in the periphery.
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Affiliation(s)
- Vurayai Ruhanya
- Division of Medical Virology, Department of Pathology, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa.,Department of Medical Microbiology, University of Zimbabwe, Harare, Zimbabwe
| | - Graeme Brendon Jacobs
- Division of Medical Virology, Department of Pathology, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
| | - Robert H Paul
- Department of Psychology and Behavioral Neuroscience, University of Missouri-St Louis, University Boulevard, St Louis, Missouri, USA
| | - John A Joska
- MRC Unit of Anxiety and Stress Disorders, Department of Psychiatry and Mental Health, University of Cape Town, Cape Town, South Africa
| | - Soraya Seedat
- MRC Unit of Anxiety and Stress Disorders, Department of Psychiatry, University of Stellenbosch, Cape Town, South Africa
| | - George Nyandoro
- Department of Medical Microbiology, University of Zimbabwe, Harare, Zimbabwe
| | - Richard Helmuth Glashoff
- Division of Medical Microbiology, Stellenbosch University, Cape Town, South Africa.,National Health Laboratory Service (NHLS), Tygerberg Business Unity, Cape Town, South Africa
| | - Susan Engelbrecht
- Division of Medical Virology, Department of Pathology, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
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6
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Sun N, Yau SST. In-depth investigation of the point mutation pattern of HIV-1. Front Cell Infect Microbiol 2022; 12:1033481. [PMID: 36457853 PMCID: PMC9705751 DOI: 10.3389/fcimb.2022.1033481] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Accepted: 10/25/2022] [Indexed: 04/29/2024] Open
Abstract
Mutations may produce highly transmissible and damaging HIV variants, which increase the genetic diversity, and pose a challenge to develop vaccines. Therefore, it is of great significance to understand how mutations drive the virulence of HIV. Based on the 11897 reliable genomes of HIV-1 retrieved from HIV sequence Database, we analyze the 12 types of point mutation (A>C, A>G, A>T, C>A, C>G, C>T, G>A, G>C, G>T, T>A, T>C, T>G) from multiple statistical perspectives for the first time. The global/geographical location/subtype/k-mer analysis results report that A>G, G>A, C>T and T>C account for nearly 64% among all SNPs, which suggest that APOBEC-editing and ADAR-editing may play an important role in HIV-1 infectivity. Time analysis shows that most genomes with abnormal mutation numbers comes from African countries. Finally, we use natural vector method to check the k-mer distribution changing patterns in the genome, and find that there is an important substitution pattern between nucleotides A and G, and 2-mer CG may have a significant impact on viral infectivity. This paper provides an insight into the single mutation of HIV-1 by using the latest data in the HIV sequence Database.
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Affiliation(s)
- Nan Sun
- Department of Mathematical Sciences, Tsinghua University, Beijing, China
| | - Stephen S.-T. Yau
- Department of Mathematical Sciences, Tsinghua University, Beijing, China
- Yanqi Lake Beijing Institute of Mathematical Sciences and Applications, Beijing, China
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7
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Han M, Woottum M, Mascarau R, Vahlas Z, Verollet C, Benichou S. Mechanisms of HIV-1 cell-to-cell transfer to myeloid cells. J Leukoc Biol 2022; 112:1261-1271. [PMID: 35355323 DOI: 10.1002/jlb.4mr0322-737r] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Revised: 03/09/2022] [Indexed: 12/24/2022] Open
Abstract
In addition to CD4+ T lymphocytes, cells of the myeloid lineage such as macrophages, dendritic cells (DCs), and osteoclasts (OCs) are emerging as important target cells for HIV-1, as they likely participate in all steps of pathogenesis, including sexual transmission and early virus dissemination in both lymphoid and nonlymphoid tissues where they can constitute persistent virus reservoirs. At least in vitro, these myeloid cells are poorly infected by cell-free viral particles. In contrast, intercellular virus transmission through direct cell-to-cell contacts may be a predominant mode of virus propagation in vivo leading to productive infection of these myeloid target cells. HIV-1 cell-to-cell transfer between CD4+ T cells mainly through the formation of the virologic synapse, or from infected macrophages or dendritic cells to CD4+ T cell targets, have been extensively described in vitro. Recent reports demonstrate that myeloid cells can be also productively infected through virus homotypic or heterotypic cell-to-cell transfer between macrophages or from virus-donor-infected CD4+ T cells, respectively. These modes of infection of myeloid target cells lead to very efficient spreading in these poorly susceptible cell types. Thus, the goal of this review is to give an overview of the different mechanisms reported in the literature for cell-to-cell transfer and spreading of HIV-1 in myeloid cells.
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Affiliation(s)
- Mingyu Han
- Institut Cochin, Inserm U1016, Paris, France.,Centre National de la Recherche Scientifique CNRS UMR8104, Paris, France.,Faculty of Health, University of Paris Cité, Paris, France
| | - Marie Woottum
- Institut Cochin, Inserm U1016, Paris, France.,Centre National de la Recherche Scientifique CNRS UMR8104, Paris, France.,Faculty of Health, University of Paris Cité, Paris, France
| | - Rémi Mascarau
- Institut de Pharmacologie et Biologie Structurale, IPBS, Université de Toulouse, CNRS, Toulouse, France.,International Research Project (IRP) CNRS, Toulouse, France.,International Research Project (IRP), CNRS, Buenos Aires, Argentina
| | - Zoï Vahlas
- Institut de Pharmacologie et Biologie Structurale, IPBS, Université de Toulouse, CNRS, Toulouse, France.,International Research Project (IRP) CNRS, Toulouse, France.,International Research Project (IRP), CNRS, Buenos Aires, Argentina
| | - Christel Verollet
- Institut de Pharmacologie et Biologie Structurale, IPBS, Université de Toulouse, CNRS, Toulouse, France.,International Research Project (IRP) CNRS, Toulouse, France.,International Research Project (IRP), CNRS, Buenos Aires, Argentina
| | - Serge Benichou
- Institut Cochin, Inserm U1016, Paris, France.,Centre National de la Recherche Scientifique CNRS UMR8104, Paris, France.,Faculty of Health, University of Paris Cité, Paris, France
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8
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Labriola JM, Miersch S, Chen G, Chen C, Pavlenco A, Saberianfar R, Caccuri F, Zani A, Sharma N, Feng A, Leung DW, Caruso A, Novelli G, Amarasinghe GK, Sidhu SS. Peptide-Antibody Fusions Engineered by Phage Display Exhibit an Ultrapotent and Broad Neutralization of SARS-CoV-2 Variants. ACS Chem Biol 2022; 17:1978-1988. [PMID: 35731947 PMCID: PMC9236212 DOI: 10.1021/acschembio.2c00411] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Accepted: 06/03/2022] [Indexed: 12/14/2022]
Abstract
The spread of COVID-19 has been exacerbated by the emergence of variants of concern (VoC). Many VoC contain mutations in the spike protein (S-protein) and are implicated in infection and response to therapeutics. Bivalent neutralizing antibodies (nAbs) targeting the S-protein receptor-binding domain (RBD) are promising therapeutics for COVID-19, but they are limited by low potency and vulnerability to RBD mutations in VoC. To address these issues, we used naïve phage-displayed peptide libraries to isolate and optimize 16-residue peptides that bind to the RBD or the N-terminal domain (NTD) of the S-protein. We fused these peptides to the N-terminus of a moderate-affinity nAb to generate tetravalent peptide-IgG fusions, and we showed that both classes of peptides were able to improve affinities for the S-protein trimer by >100-fold (apparent KD < 1 pM). Critically, cell-based infection assays with a panel of six SARS-CoV-2 variants demonstrated that an RBD-binding peptide was able to enhance the neutralization potency of a high-affinity nAb >100-fold. Moreover, this peptide-IgG was able to neutralize variants that were resistant to the same nAb in the bivalent IgG format, including the dominant B.1.1.529 (Omicron) variant that is resistant to most clinically approved therapeutic nAbs. To show that this approach is general, we fused the same peptide to a clinically approved nAb drug and showed that it enabled the neutralization of a resistant variant. Taken together, these results establish minimal peptide fusions as a modular means to greatly enhance affinities, potencies, and breadth of coverage of nAbs as therapeutics for SARS-CoV-2.
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Affiliation(s)
- Jonathan M. Labriola
- Department of Molecular Genetics, The
Donnelly Centre, University of Toronto, 160 College St., M5S 3E1 Toronto,
Ontario, Canada
| | - Shane Miersch
- Department of Molecular Genetics, The
Donnelly Centre, University of Toronto, 160 College St., M5S 3E1 Toronto,
Ontario, Canada
| | - Gang Chen
- Department of Molecular Genetics, The
Donnelly Centre, University of Toronto, 160 College St., M5S 3E1 Toronto,
Ontario, Canada
| | - Chao Chen
- Department of Molecular Genetics, The
Donnelly Centre, University of Toronto, 160 College St., M5S 3E1 Toronto,
Ontario, Canada
| | - Alevtina Pavlenco
- Department of Molecular Genetics, The
Donnelly Centre, University of Toronto, 160 College St., M5S 3E1 Toronto,
Ontario, Canada
| | - Reza Saberianfar
- Department of Molecular Genetics, The
Donnelly Centre, University of Toronto, 160 College St., M5S 3E1 Toronto,
Ontario, Canada
| | - Francesca Caccuri
- Section of Microbiology, Department of Molecular and
Translational Medicine, University of Brescia Medical School,
25123 Brescia, Italy
| | - Alberto Zani
- Section of Microbiology, Department of Molecular and
Translational Medicine, University of Brescia Medical School,
25123 Brescia, Italy
| | - Nitin Sharma
- Department of Pathology and Immunology,
Washington University School of Medicine in St Louis, St
Louis, Missouri 63110, United States
| | - Annie Feng
- Department of Pathology and Immunology,
Washington University School of Medicine in St Louis, St
Louis, Missouri 63110, United States
- Division of Infectious Diseases, John T. Milliken
Department of Medicine, Washington University School of
Medicine, St. Louis, Missouri 63110, United
States
| | - Daisy W. Leung
- Division of Infectious Diseases, John T. Milliken
Department of Medicine, Washington University School of
Medicine, St. Louis, Missouri 63110, United
States
| | - Arnaldo Caruso
- Section of Microbiology, Department of Molecular and
Translational Medicine, University of Brescia Medical School,
25123 Brescia, Italy
| | - Giuseppe Novelli
- Department of Biomedicine and Prevention,
University of Rome Tor Vergata, Via Montpellier 1, 00133
Rome, Italy
- Italy 6 IRCCS Neuromed, Pozzilli
(IS) 86077, Italy
- Department of Pharmacology, School of Medicine,
University of Nevada, Reno, Nevada 89557, United
States
| | - Gaya K. Amarasinghe
- Department of Pathology and Immunology,
Washington University School of Medicine in St Louis, St
Louis, Missouri 63110, United States
| | - Sachdev S. Sidhu
- Department of Molecular Genetics, The
Donnelly Centre, University of Toronto, 160 College St., M5S 3E1 Toronto,
Ontario, Canada
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9
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Thippeshappa R, Polacino P, Chandrasekar SS, Truong K, Misra A, Aulicino PC, Hu SL, Kaushal D, Kimata JT. In vivo Serial Passaging of Human-Simian Immunodeficiency Virus Clones Identifies Characteristics for Persistent Viral Replication. Front Microbiol 2021; 12:779460. [PMID: 34867922 PMCID: PMC8636705 DOI: 10.3389/fmicb.2021.779460] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2021] [Accepted: 10/22/2021] [Indexed: 12/11/2022] Open
Abstract
We previously reported that a human immunodeficiency virus type 1 with a simian immunodeficiency virus vif substitution (HSIV-vifNL4-3) could replicate in pigtailed macaques (PTMs), demonstrating that Vif is a species-specific tropism factor of primate lentiviruses. However, infections did not result in high-peak viremia or setpoint plasma viral loads, as observed during simian immunodeficiency virus (SIV) infection of PTMs. Here, we characterized variants isolated from one of the original infected animals with CD4 depletion after nearly 4years of infection to identify determinants of increased replication fitness. In our studies, we found that the HSIV-vif clones did not express the HIV-1 Vpr protein due to interference from the vpx open reading frame (ORF) in singly spliced vpr mRNA. To examine whether these viral genes contribute to persistent viral replication, we generated infectious HSIV-vif clones expressing either the HIV-1 Vpr or SIV Vpx protein. And then to determine viral fitness determinants of HSIV-vif, we conducted three rounds of serial in vivo passaging in PTMs, starting with an initial inoculum containing a mixture of CXCR4-tropic [Vpr-HSIV-vifNL4-3 isolated at 196 (C/196) and 200 (C/200) weeks post-infection from a PTM with depressed CD4 counts] and CCR5-tropic HSIV (Vpr+ HSIV-vif derivatives based NL-AD8 and Bru-Yu2 and a Vpx expressing HSIV-vifYu2). Interestingly, all infected PTMs showed peak plasma viremia close to or above 105 copies/ml and persistent viral replication for more than 20weeks. Infectious molecular clones (IMCs) recovered from the passage 3 PTM (HSIV-P3 IMCs) included mutations required for HIV-1 Vpr expression and those mutations encoded by the CXCR4-tropic HSIV-vifNL4-3 isolate C/196. The data indicate that the viruses selected during long-term infection acquired HIV-1 Vpr expression, suggesting the importance of Vpr for in vivo pathogenesis. Further passaging of HSIV-P3 IMCs in vivo may generate pathogenic variants with higher replication capacity, which will be a valuable resource as challenge virus in vaccine and cure studies.
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Affiliation(s)
- Rajesh Thippeshappa
- Disease Intervention and Prevention Program, Southwest National Primate Research Center, Texas Biomedical Research Institute, San Antonio, TX, United States
| | - Patricia Polacino
- Washington National Primate Research Center, University of Washington, Seattle, WA, United States
| | - Shaswath S Chandrasekar
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, United States
| | - Khanghy Truong
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, United States
| | - Anisha Misra
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, United States
| | - Paula C Aulicino
- Laboratorio de Biología Celular y Retrovirus, Hospital de Pediatría "Juan P. Garrahan"-CONICET, Buenos Aires, Argentina
| | - Shiu-Lok Hu
- Washington National Primate Research Center, University of Washington, Seattle, WA, United States.,Department of Pharmaceutics, University of Washington, Seattle, WA, United States
| | - Deepak Kaushal
- Host-Pathogen Interactions Program, Southwest National Primate Research Center, Texas Biomedical Research Institute, San Antonio, TX, United States
| | - Jason T Kimata
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, United States
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10
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HIV-1 Gag Recruits Oligomeric Vpr via Two Binding Sites in p6, but Both Mature p6 and Vpr Are Rapidly Lost upon Target Cell Entry. J Virol 2021; 95:e0055421. [PMID: 34106747 DOI: 10.1128/jvi.00554-21] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The p12 region of murine leukemia virus (MLV) Gag and the p6 region of HIV-1 Gag contain late domains required for virus budding. Additionally, the accessory protein Vpr is recruited into HIV particles via p6. Mature p12 is essential for early viral replication events, but the role of mature p6 in early replication is unknown. Using a proviral vector in which the gag and pol reading frames are uncoupled, we have performed the first alanine-scanning mutagenesis screens across p6 to probe its importance for early HIV-1 replication and to further understand its interaction with Vpr. The infectivity of our mutants suggests that, unlike p12, p6 is not important for early viral replication. Consistent with this, we observed that p6 is rapidly lost upon target cell entry in time course immunoblot experiments. By analyzing Vpr incorporation into p6 mutant virions, we identified that the 15-FRFG-18 and 41-LXXLF-45 motifs previously identified as putative Vpr-binding sites are important for Vpr recruitment but that the 34-ELY-36 motif also suggested to be a Vpr-binding site is dispensable. Additionally, disrupting Vpr oligomerization together with removing either binding motif in p6 reduced Vpr incorporation ∼25- to 50-fold more than inhibiting Vpr oligomerization alone and ∼10- to 25-fold more than deleting each p6 motif alone, implying that multivalency/avidity is important for the interaction. Interestingly, using immunoblotting and immunofluorescence, we observed that most Vpr is lost concomitantly with p6 during infection but that a small fraction remains associated with the viral capsid for several hours. This has implications for the function of Vpr in early replication. IMPORTANCE The p12 protein of MLV and the p6 protein of HIV-1 are both supplementary Gag cleavage products that carry proline-rich motifs that facilitate virus budding. Importantly, p12 has also been found to be essential for early viral replication events. However, while Vpr, the only accessory protein packaged into HIV-1 virions, is recruited via the p6 region of Gag, the function of both mature p6 and Vpr in early replication is unclear. Here, we have systematically mutated the p6 region of Gag and have studied the effects on HIV infectivity and Vpr packaging. We have also investigated what happens to p6 and Vpr during early infection. We show that, unlike p12, mature p6 is not required for early replication and that most of the mature p6 and the Vpr that it recruits are lost rapidly upon target cell entry. This has implications for the role of Vpr in target cells.
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11
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Lubow J, Collins KL. Vpr Is a VIP: HIV Vpr and Infected Macrophages Promote Viral Pathogenesis. Viruses 2020; 12:E809. [PMID: 32726944 PMCID: PMC7472745 DOI: 10.3390/v12080809] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 07/17/2020] [Accepted: 07/23/2020] [Indexed: 02/06/2023] Open
Abstract
HIV infects several cell types in the body, including CD4+ T cells and macrophages. Here we review the role of macrophages in HIV infection and describe complex interactions between viral proteins and host defenses in these cells. Macrophages exist in many forms throughout the body, where they play numerous roles in healthy and diseased states. They express pattern-recognition receptors (PRRs) that bind viral, bacterial, fungal, and parasitic pathogens, making them both a key player in innate immunity and a potential target of infection by pathogens, including HIV. Among these PRRs is mannose receptor, a macrophage-specific protein that binds oligosaccharides, restricts HIV replication, and is downregulated by the HIV accessory protein Vpr. Vpr significantly enhances infection in vivo, but the mechanism by which this occurs is controversial. It is well established that Vpr alters the expression of numerous host proteins by using its co-factor DCAF1, a component of the DCAF1-DDB1-CUL4 ubiquitin ligase complex. The host proteins targeted by Vpr and their role in viral replication are described in detail. We also discuss the structure and function of the viral protein Env, which is stabilized by Vpr in macrophages. Overall, this literature review provides an updated understanding of the contributions of macrophages and Vpr to HIV pathogenesis.
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Affiliation(s)
- Jay Lubow
- Department of Microbiology & Immunology, University of Michigan, Ann Arbor, MI 48109, USA;
| | - Kathleen L. Collins
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48109, USA
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12
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Kara H, Chazal N, Bouaziz S. Is Uracil-DNA Glycosylase UNG2 a New Cellular Weapon Against HIV-1? Curr HIV Res 2020; 17:148-160. [PMID: 31433761 DOI: 10.2174/1570162x17666190821154331] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2019] [Revised: 08/01/2019] [Accepted: 08/09/2019] [Indexed: 01/12/2023]
Abstract
Uracil-DNA glycosylase-2 (UNG2) is a DNA repair protein that removes uracil from single and double-stranded DNA through a basic excision repair process. UNG2 is packaged into new virions by interaction with integrase (IN) and is needed during the early stages of the replication cycle. UNG2 appears to play both a positive and negative role during HIV-1 replication; UNG2 improves the fidelity of reverse transcription but the nuclear isoform of UNG2 participates in the degradation of cDNA and the persistence of the cellular genome by repairing its uracil mismatches. In addition, UNG2 is neutralized by Vpr, which redirects it to the proteasome for degradation, suggesting that UNG2 may be a new cellular restriction factor. So far, we have not understood why HIV-1 imports UNG2 via its IN and why it causes degradation of endogenous UNG2 by redirecting it to the proteasome via Vpr. In this review, we propose to discuss the ambiguous role of UNG2 during the HIV-1 replication cycle.
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Affiliation(s)
- Hesna Kara
- Cibles Therapeutiques et Conception de Medicaments (CiTCoM), CNRS UMR8038, Faculte des Sciences Pharmaceutiques et Biologiques, Universite Paris Descartes, Paris, France
| | - Nathalie Chazal
- Institut de Recherche en Infectiologie de Montpellier (IRIM), CNRS UMR9004, Universite de Montpellier, Montpellier, France
| | - Serge Bouaziz
- Cibles Therapeutiques et Conception de Medicaments (CiTCoM), CNRS UMR8038, Faculte des Sciences Pharmaceutiques et Biologiques, Universite Paris Descartes, Paris, France
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13
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Wallet C, Rohr O, Schwartz C. Evolution of a concept: From accessory protein to key virulence factor, the case of HIV-1 Vpr. Biochem Pharmacol 2020; 180:114128. [PMID: 32619426 DOI: 10.1016/j.bcp.2020.114128] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 06/24/2020] [Accepted: 06/25/2020] [Indexed: 12/12/2022]
Abstract
Back in 1989 some studies have shown that the viral protein Vpr was dispensable for HIV-1 replication in vitro. From then the concept of accessory or auxiliary protein for Vpr has emerged and it is still used to date. However, Vpr soon appeared to be very important for in vivo virus spread and pathogenesis. Vpr has been involved in many biological functions including regulation of reverse transcriptase activity, the nuclear import of the pre-integration complex (PIC), HIV-1 transcription, gene splicing, apoptosis and in cell cycle arrest. Thus, we might rather consider Vpr as a true virulence factor instead of just an accessory factor. At present, Vpr can be regarded as a potential and promising target in different strategies aiming to fight infected cells including latently infected cells.
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Affiliation(s)
- Clémentine Wallet
- University of Strasbourg, Research Unit7292, DHPI, IUT Louis Pasteur, Schiltigheim, France
| | - Olivier Rohr
- University of Strasbourg, Research Unit7292, DHPI, IUT Louis Pasteur, Schiltigheim, France
| | - Christian Schwartz
- University of Strasbourg, Research Unit7292, DHPI, IUT Louis Pasteur, Schiltigheim, France.
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14
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HIV-1 Accessory Protein Vpr Interacts with REAF/RPRD2 To Mitigate Its Antiviral Activity. J Virol 2020; 94:JVI.01591-19. [PMID: 31776272 DOI: 10.1128/jvi.01591-19] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Accepted: 10/29/2019] [Indexed: 12/18/2022] Open
Abstract
The human immunodeficiency virus type 1 (HIV-1) accessory protein Vpr enhances viral replication in both macrophages and, to a lesser extent, cycling T cells. Virion-packaged Vpr is released in target cells shortly after entry, suggesting it is required in the early phase of infection. Previously, we described REAF (RNA-associated early-stage antiviral factor; RPRD2), a constitutively expressed protein that potently restricts HIV replication at or during reverse transcription. Here, we show that a virus without an intact vpr gene is more highly restricted by REAF and, using delivery by virus-like particles (VLPs), that Vpr alone is sufficient for REAF degradation in primary macrophages. REAF is more highly expressed in macrophages than in cycling T cells, and we detected, by coimmunoprecipitation assay, an interaction between Vpr protein and endogenous REAF. Vpr acts quickly during the early phase of replication and induces the degradation of REAF within 30 min of viral entry. Using Vpr F34I and Q65R viral mutants, we show that nuclear localization and interaction with cullin 4A-DBB1 (DCAF1) E3 ubiquitin ligase are required for REAF degradation by Vpr. In response to infection, cells upregulate REAF levels. This response is curtailed in the presence of Vpr. These findings support the hypothesis that Vpr induces the degradation of a factor, REAF, that impedes HIV infection in macrophages.IMPORTANCE For at least 30 years, it has been known that HIV-1 Vpr, a protein carried in the virion, is important for efficient infection of primary macrophages. Vpr is also a determinant of the pathogenic effects of HIV-1 in vivo A number of cellular proteins that interact with Vpr have been identified. So far, it has not been possible to associate these proteins with altered viral replication in macrophages or to explain why Vpr is carried in the virus particle. Here, we show that Vpr mitigates the antiviral effects of REAF, a protein highly expressed in primary macrophages and one that inhibits virus replication during reverse transcription. REAF is degraded by Vpr within 30 min of virus entry in a manner dependent on the nuclear localization of Vpr and its interaction with the cell's protein degradation machinery.
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15
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Vpr and Its Cellular Interaction Partners: R We There Yet? Cells 2019; 8:cells8111310. [PMID: 31652959 PMCID: PMC6912716 DOI: 10.3390/cells8111310] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Revised: 10/22/2019] [Accepted: 10/23/2019] [Indexed: 12/17/2022] Open
Abstract
Vpr is a lentiviral accessory protein that is expressed late during the infection cycle and is packaged in significant quantities into virus particles through a specific interaction with the P6 domain of the viral Gag precursor. Characterization of the physiologically relevant function(s) of Vpr has been hampered by the fact that in many cell lines, deletion of Vpr does not significantly affect viral fitness. However, Vpr is critical for virus replication in primary macrophages and for viral pathogenesis in vivo. It is generally accepted that Vpr does not have a specific enzymatic activity but functions as a molecular adapter to modulate viral or cellular processes for the benefit of the virus. Indeed, many Vpr interacting factors have been described by now, and the goal of this review is to summarize our current knowledge of cellular proteins targeted by Vpr.
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16
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Wang Q, Su L. Vpr Enhances HIV-1 Env Processing and Virion Infectivity in Macrophages by Modulating TET2-Dependent IFITM3 Expression. mBio 2019; 10:e01344-19. [PMID: 31431548 PMCID: PMC6703422 DOI: 10.1128/mbio.01344-19] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Accepted: 07/24/2019] [Indexed: 12/28/2022] Open
Abstract
HIV-1 Vpr enhances viral replication in human macrophages via multiple mechanisms that are not clearly defined. It does not affect HIV-1 virion production during the first round of infection. We have recently discovered that Vpr targets the DNA demethylase TET2 for degradation, which leads to sustained interleukin-6 (IL-6) expression and elevated HIV-1 replication. We report here that Vpr enhanced Env processing in infected macrophages, associated with increased Env incorporation into virions with higher infectivity. Interestingly, IFITM3 was constitutively expressed in macrophages in a TET2-dependent fashion. We showed that Vpr-enhanced Env processing depended genetically on TET2 and IFITM3. We further showed that Vpr reduced IFITM3 expression by reducing demethylation of the IFITM3 promoter in macrophages, associated with degradation of TET2 and reduced TET2 binding to the IFITIM3 promoter. Our findings indicate that the Vpr-TET2 axis enhances HIV-1 replication in macrophages via two independent mechanisms: reduced IFTIM3 expression to enhance Env processing and virion infectivity and sustained IL-6 expression to increase HIV-1 replication. The Vpr-TET2 axis may provide a novel target to develop therapeutics to inhibit HIV-1 infection and pathogenesis.IMPORTANCE How Vpr enhances HIV-1 replication in macrophages is still unclear. We report here that Vpr enhanced HIV-1 Env processing during the first round of HIV-1 replication, resulting in virions with higher Env incorporation and viral infectivity. These higher-quality viral particles contributed to elevated infection during the second round and spreading infection in macrophages and other HIV-1 target cells. We have recently discovered that TET2 is a novel host factor degraded by Vpr, which leads to sustained IL-6 expression in macrophages. Interestingly, Vpr-enhanced HIV-1 Env processing depended on both the IFITIM3 and TET2 genes. The constitutive expression of IFITIM3 expression in macrophages was maintained by TET2, which demethylated the IFITIM3 promoter. We conclude that the Vpr degrades TET2 to enhance HIV-1 replication in macrophages by reducing IFITIM3 expression to increase viral Env processing, virion incorporation, and infectivity and by sustaining IL-6 expression to increase HIV-1 gene expression. The Vpr-TET2 axis may serve as a novel target to develop anti-HIV drugs to inhibit HIV-1 infection and pathogenesis.
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Affiliation(s)
- Qi Wang
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
- Department of Microbiology & Immunology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Lishan Su
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
- Department of Microbiology & Immunology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
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17
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Infectious Virus Persists in CD4 + T Cells and Macrophages in Antiretroviral Therapy-Suppressed Simian Immunodeficiency Virus-Infected Macaques. J Virol 2019; 93:JVI.00065-19. [PMID: 31118264 PMCID: PMC6639293 DOI: 10.1128/jvi.00065-19] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Accepted: 05/01/2019] [Indexed: 02/08/2023] Open
Abstract
This study suggests that CD4+ T cells found throughout tissues in the body can contain replication-competent SIV and contribute to rebound of the virus after treatment interruption. In addition, this study demonstrates that macrophages in tissues are another cellular reservoir for SIV and may contribute to viral rebound after treatment interruption. This new insight into the size and location of the SIV reservoir could have great implications for HIV-infected individuals and should be taken into consideration for the development of future HIV cure strategies. Understanding the cellular and anatomical sites of latent virus that contribute to human immunodeficiency virus (HIV) rebound is essential for eradication. In HIV-positive patients, CD4+ T lymphocytes comprise a well-defined functional latent reservoir, defined as cells containing transcriptionally silent genomes able to produce infectious virus once reactivated. However, the persistence of infectious latent virus in CD4+ T cells in compartments other than blood and lymph nodes is unclear. Macrophages (Mϕ) are infected by HIV/simian immunodeficiency virus (SIV) and are likely to carry latent viral genomes during antiretroviral therapy (ART), contributing to the reservoir. Currently, the gold standard assay used to measure reservoirs containing replication-competent virus is the quantitative viral outgrowth assay (QVOA). Using an SIV-macaque model, the CD4+ T cell and Mϕ functional latent reservoirs were measured in various tissues using cell-specific QVOAs. Our results showed that blood, spleen, and lung in the majority of suppressed animals contain latently infected Mϕs. Surprisingly, the numbers of CD4+ T cells, monocytes, and Mϕs carrying infectious genomes in blood and spleen were at comparable frequencies (∼1 infected cell per million). We also demonstrate that ex vivo viruses produced in the Mϕ QVOA are capable of infecting activated CD4+ T cells. These results strongly suggest that latently infected tissue Mϕs can reestablish productive infection upon treatment interruption. This study provides the first comparison of CD4+ T cell and Mϕ functional reservoirs in a macaque model. It is the first confirmation of the persistence of latent genomes in monocytes in blood and Mϕs in the spleen and lung of SIV-infected ART-suppressed macaques. Our results demonstrate that transcriptionally silent genomes in Mϕs can contribute to viral rebound after ART interruption and should be considered in future HIV cure strategies. IMPORTANCE This study suggests that CD4+ T cells found throughout tissues in the body can contain replication-competent SIV and contribute to rebound of the virus after treatment interruption. In addition, this study demonstrates that macrophages in tissues are another cellular reservoir for SIV and may contribute to viral rebound after treatment interruption. This new insight into the size and location of the SIV reservoir could have great implications for HIV-infected individuals and should be taken into consideration for the development of future HIV cure strategies.
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18
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Kushwaha P, Ahmad N, Dhar YV, Verma A, Haldar S, Mulani FA, Trivedi PK, Mishra PR, Thulasiram HV, Trivedi R. Estrogen receptor activation in response to Azadirachtin A stimulates osteoblast differentiation and bone formation in mice. J Cell Physiol 2019; 234:23719-23735. [DOI: 10.1002/jcp.28940] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2018] [Revised: 05/15/2019] [Accepted: 05/22/2019] [Indexed: 12/23/2022]
Affiliation(s)
| | - Naseer Ahmad
- Endocrinology CSIR‐Central Drug Research Institute Lucknow India
| | - Yogeshwar V. Dhar
- Molecular Biology and Biotechnology CSIR‐National Botanical Research Institute Lucknow India
| | - Ashwni Verma
- Pharmaceutics Division CSIR‐Central Drug Research Institute Lucknow India
| | - Saikat Haldar
- Organic Chemistry Division CSIR‐National Chemical Laboratory Pune India
| | - Fayaj A. Mulani
- Organic Chemistry Division CSIR‐National Chemical Laboratory Pune India
| | - Prabodh K. Trivedi
- Molecular Biology and Biotechnology CSIR‐National Botanical Research Institute Lucknow India
| | - Prabhat R. Mishra
- Pharmaceutics Division CSIR‐Central Drug Research Institute Lucknow India
| | | | - Ritu Trivedi
- Endocrinology CSIR‐Central Drug Research Institute Lucknow India
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19
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Targeting uracil-DNA glycosylases for therapeutic outcomes using insights from virus evolution. Future Med Chem 2019; 11:1323-1344. [PMID: 31161802 DOI: 10.4155/fmc-2018-0319] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Ung-type uracil-DNA glycosylases are frontline defenders of DNA sequence fidelity in bacteria, plants and animals; Ungs also directly assist both innate and humoral immunity. Critically important in viral pathogenesis, whether acting for or against viral DNA persistence, Ungs also have therapeutic relevance to cancer, microbial and parasitic diseases. Ung catalytic specificity is uniquely conserved, yet selective antiviral drugging of the Ung catalytic pocket is tractable. However, more promising precision therapy approaches present themselves via insights from viral strategies, including sequestration or adaptation of Ung for noncanonical roles. A universal Ung inhibition mechanism, converged upon by unrelated viruses, could also inform design of compounds to inhibit specific distinct Ungs. Extrapolating current developments, the character of such novel chemical entities is proposed.
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20
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Yan J, Shun MC, Zhang Y, Hao C, Skowronski J. HIV-1 Vpr counteracts HLTF-mediated restriction of HIV-1 infection in T cells. Proc Natl Acad Sci U S A 2019; 116:9568-9577. [PMID: 31019079 PMCID: PMC6511057 DOI: 10.1073/pnas.1818401116] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Lentiviruses, including HIV-1, possess the ability to enter the nucleus through nuclear pore complexes and can infect interphase cells, including those actively replicating chromosomal DNA. Viral accessory proteins hijack host cell E3 enzymes to antagonize intrinsic defenses, and thereby provide a more permissive environment for virus replication. The HIV-1 Vpr accessory protein reprograms CRL4DCAF1 E3 to antagonize select postreplication DNA repair enzymes and activates the DNA damage checkpoint in the G2 cell cycle phase. However, little is known about the roles played by these Vpr targets in HIV-1 replication. Here, using a sensitive pairwise replication competition assay, we show that Vpr endows HIV-1 with a strong replication advantage in activated primary CD4+ T cells and established T cell lines. This effect is disabled by a Vpr mutation that abolishes binding to CRL4DCAF1 E3, thereby disrupting Vpr antagonism of helicase-like transcription factor (HLTF) DNA helicase and other DNA repair pathway targets, and by another mutation that prevents induction of the G2 DNA damage checkpoint. Consistent with these findings, we also show that HLTF restricts HIV-1 replication, and that this restriction is antagonized by HIV-1 Vpr. Furthermore, our data imply that HIV-1 Vpr uses additional, yet to be identified mechanisms to facilitate HIV-1 replication in T cells. Overall, we demonstrate that multiple aspects of the cellular DNA repair machinery restrict HIV-1 replication in dividing T cells, the primary target of HIV-1 infection, and describe newly developed approaches to dissect key components.
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Affiliation(s)
- Junpeng Yan
- Department of Molecular Biology and Microbiology, Case Western Reserve School of Medicine, Cleveland, OH 44106
| | - Ming-Chieh Shun
- Department of Molecular Biology and Microbiology, Case Western Reserve School of Medicine, Cleveland, OH 44106
| | - Yi Zhang
- Department of Molecular Biology and Microbiology, Case Western Reserve School of Medicine, Cleveland, OH 44106
| | - Caili Hao
- Department of Molecular Biology and Microbiology, Case Western Reserve School of Medicine, Cleveland, OH 44106
| | - Jacek Skowronski
- Department of Molecular Biology and Microbiology, Case Western Reserve School of Medicine, Cleveland, OH 44106
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21
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Abreu C, Shirk EN, Queen SE, Mankowski JL, Gama L, Clements JE. A Quantitative Approach to SIV Functional Latency in Brain Macrophages. J Neuroimmune Pharmacol 2019; 14:23-32. [PMID: 30167896 PMCID: PMC9070040 DOI: 10.1007/s11481-018-9803-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Accepted: 08/15/2018] [Indexed: 12/23/2022]
Abstract
Lentiviruses are retroviruses that primarily infect myeloid cells, leading to acute inflammatory infections in many tissues particularly, lung, joints and the central nervous system (CNS). Acute infection by lentiviruses is followed by persistent/latent infections that are not cleared by the host immune system. HIV and SIV are lentiviruses that also infect CD4+ lymphocytes as well as myeloid cells in blood and multiple tissues. HIV infection of myeloid cells in brain, lung and heart cause tissue specific diseases as well as infect cells in gut, lymph nodes and spleen. AIDS dementia and other tissue specific disease are observed when infected individuals are immunosuppressed and the number of circulating CD4+ T cells declines to low levels. Antiretroviral therapy (ART) controls viral spread and dramatically changes the course of immunodeficiency and AIDS dementia. However, ART does not eliminate virus-infected cells. Brain macrophages contain HIV DNA and may represent a latent reservoir that persists. HIV latency in CD4+ lymphocytes is the main focus of current research and concern in efforts to eradicate HIV. However, a number of studies have demonstrated that myeloid cells in blood and tissues of ART suppressed individuals harbor HIV DNA. The resident macrophages in tissues such as brain (microglia), spleen (red pulp macrophages) and alveolar macrophages in lung are derived from the yolk sac and can self renew. The question of the latent myeloid reservoir in HIV has not been rigorously examined and its potential as a barrier to eradication been considered. Using a well characterized SIV ART suppressed, non-human primate (NHP) model, our laboratory developed the first quantitative viral outgrowth assay (QVOA) designed to evaluate latently infected CD4+ lymphocytes and more recently developed a similar protocol for the assessment of latently infected myeloid cells in blood and brain. Using an SIV ART model, it was demonstrated that myeloid cells in blood and brain harbor latent SIV that can be reactivated and produce infectious virus in vitro. These studies demonstrate for the first time that myeloid cells have the potential to be a latent reservoir of HIV that produces infectious virus that can be reactivated in the absence of ART and during HIV eradication strategies. Graphical Abstract.
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Affiliation(s)
- Celina Abreu
- Department of Molecular and Comparative Pathobiology, Johns Hopkins University, Baltimore, MD, 21205, USA
| | - Erin N Shirk
- Department of Molecular and Comparative Pathobiology, Johns Hopkins University, Baltimore, MD, 21205, USA
| | - Suzanne E Queen
- Department of Molecular and Comparative Pathobiology, Johns Hopkins University, Baltimore, MD, 21205, USA
| | - Joseph L Mankowski
- Department of Molecular and Comparative Pathobiology, Johns Hopkins University, Baltimore, MD, 21205, USA
- Department of Neurology, Johns Hopkins University, Baltimore, MD, 21205, USA
- Department of Pathology, Johns Hopkins University, Baltimore, MD, 21205, USA
| | - Lucio Gama
- Department of Molecular and Comparative Pathobiology, Johns Hopkins University, Baltimore, MD, 21205, USA
| | - Janice E Clements
- Department of Molecular and Comparative Pathobiology, Johns Hopkins University, Baltimore, MD, 21205, USA.
- Department of Neurology, Johns Hopkins University, Baltimore, MD, 21205, USA.
- Department of Pathology, Johns Hopkins University, Baltimore, MD, 21205, USA.
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22
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Gama L, Abreu C, Shirk EN, Queen SE, Beck SE, Metcalf Pate KA, Bullock BT, Zink MC, Mankowski JL, Clements JE. SIV Latency in Macrophages in the CNS. Curr Top Microbiol Immunol 2018; 417:111-130. [PMID: 29770863 DOI: 10.1007/82_2018_89] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Lentiviruses infect myeloid cells, leading to acute infection followed by persistent/latent infections not cleared by the host immune system. HIV and SIV are lentiviruses that infect CD4+ lymphocytes in addition to myeloid cells in blood and tissues. HIV infection of myeloid cells in brain, lung, and heart causes tissue-specific diseases that are mostly observed during severe immunosuppression, when the number of circulating CD4+ T cells declines to exceeding low levels. Antiretroviral therapy (ART) controls viral replication but does not successfully eliminate latent virus, which leads to viral rebound once ART is interrupted. HIV latency in CD4+ lymphocytes is the main focus of research and concern when HIV eradication efforts are considered. However, myeloid cells in tissues are long-lived and have not been routinely examined as a potential reservoir. Based on a quantitative viral outgrowth assay (QVOA) designed to evaluate latently infected CD4+ lymphocytes, a similar protocol was developed for the assessment of latently infected myeloid cells in blood and tissues. Using an SIV ART model, it was demonstrated that myeloid cells in blood and brain harbor latent SIV that can be reactivated and produce infectious virus in vitro, demonstrating that myeloid cells have the potential to be an additional latent reservoir of HIV that should be considered during HIV eradication strategies.
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Affiliation(s)
- Lucio Gama
- Department of Molecular and Comparative Pathobiology, Johns Hopkins University, Baltimore, MD, 21205, USA
| | - Celina Abreu
- Department of Molecular and Comparative Pathobiology, Johns Hopkins University, Baltimore, MD, 21205, USA
| | - Erin N Shirk
- Department of Molecular and Comparative Pathobiology, Johns Hopkins University, Baltimore, MD, 21205, USA
| | - Suzanne E Queen
- Department of Molecular and Comparative Pathobiology, Johns Hopkins University, Baltimore, MD, 21205, USA
| | - Sarah E Beck
- Department of Molecular and Comparative Pathobiology, Johns Hopkins University, Baltimore, MD, 21205, USA
| | - Kelly A Metcalf Pate
- Department of Molecular and Comparative Pathobiology, Johns Hopkins University, Baltimore, MD, 21205, USA
| | - Brandon T Bullock
- Department of Molecular and Comparative Pathobiology, Johns Hopkins University, Baltimore, MD, 21205, USA
| | - M Christine Zink
- Department of Molecular and Comparative Pathobiology, Johns Hopkins University, Baltimore, MD, 21205, USA
| | - Joseph L Mankowski
- Department of Molecular and Comparative Pathobiology, Johns Hopkins University, Baltimore, MD, 21205, USA.,Department of Neurology, Johns Hopkins University, Baltimore, MD, 21205, USA.,Department of Pathology, Johns Hopkins University, Baltimore, MD, 21205, USA
| | - Janice E Clements
- Department of Molecular and Comparative Pathobiology, Johns Hopkins University, Baltimore, MD, 21205, USA. .,Department of Neurology, Johns Hopkins University, Baltimore, MD, 21205, USA. .,Department of Pathology, Johns Hopkins University, Baltimore, MD, 21205, USA.
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23
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Faust TB, Binning JM, Gross JD, Frankel AD. Making Sense of Multifunctional Proteins: Human Immunodeficiency Virus Type 1 Accessory and Regulatory Proteins and Connections to Transcription. Annu Rev Virol 2017; 4:241-260. [PMID: 28961413 DOI: 10.1146/annurev-virology-101416-041654] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Viruses are completely dependent upon cellular machinery to support replication and have therefore developed strategies to co-opt cellular processes to optimize infection and counter host immune defenses. Many viruses, including human immunodeficiency virus type 1 (HIV-1), encode a relatively small number of genes. Viruses with limited genetic content often encode multifunctional proteins that function at multiple stages of the viral replication cycle. In this review, we discuss the functions of HIV-1 regulatory (Tat and Rev) and accessory (Vif, Vpr, Vpu, and Nef) proteins. Each of these proteins has a highly conserved primary activity; however, numerous additional activities have been attributed to these viral proteins. We explore the possibility that HIV-1 proteins leverage their multifunctional nature to alter host transcriptional networks to elicit a diverse set of cellular responses. Although these transcriptional effects appear to benefit the virus, it is not yet clear whether they are strongly selected for during viral evolution or are a ripple effect from the primary function. As our detailed knowledge of these viral proteins improves, we will undoubtedly uncover how the multifunctional nature of these HIV-1 regulatory and accessory proteins, and in particular their transcriptional functions, work to drive viral pathogenesis.
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Affiliation(s)
- Tyler B Faust
- Department of Biochemistry and Biophysics, University of California, San Francisco, California 94158; ,
| | - Jennifer M Binning
- Department of Pharmaceutical Chemistry, University of California, San Francisco, California 94158; ,
| | - John D Gross
- Department of Pharmaceutical Chemistry, University of California, San Francisco, California 94158; ,
| | - Alan D Frankel
- Department of Biochemistry and Biophysics, University of California, San Francisco, California 94158; ,
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24
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Yaseen MM, Abuharfeil NM, Alqudah MA, Yaseen MM. Mechanisms and Factors That Drive Extensive Human Immunodeficiency Virus Type-1 Hypervariability: An Overview. Viral Immunol 2017; 30:708-726. [PMID: 29064351 DOI: 10.1089/vim.2017.0065] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The extensive hypervariability of human immunodeficiency virus type-1 (HIV-1) populations represents a major barrier against the success of currently available antiretroviral therapy. Moreover, it is still the most important obstacle that faces the development of an effective preventive vaccine against this infectious virus. Indeed, several factors can drive such hypervariability within and between HIV-1 patients. These factors include: first, the very low fidelity nature of HIV-1 reverse transcriptase; second, the extremely high HIV-1 replication rate; and third, the high genomic recombination rate that the virus has. All these factors together with the APOBEC3 proteins family and the immune and antiviral drugs pressures drive the extensive hypervariability of HIV-1 populations. Studying these factors and the mechanisms that drive such hypervariability will provide valuable insights that may guide the development of effective therapeutic and preventive strategies against HIV-1 infection in the near future. To this end, in this review, we summarized recent advances in this area of HIV-1 research.
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Affiliation(s)
- Mahmoud Mohammad Yaseen
- 1 Department of Medical Laboratory Sciences, College of Applied Medical Sciences, Jordan University of Science and Technology , Irbid, Jordan
| | - Nizar Mohammad Abuharfeil
- 2 Department of Applied Biological Sciences, College of Science and Arts, Jordan University of Science and Technology , Irbid, Jordan
| | - Mohammad Ali Alqudah
- 3 Department of Clinical Pharmacy, College of Pharmacy, Jordan University of Science and Technology , Irbid, Jordan
| | - Mohammad Mahmoud Yaseen
- 4 Department of Public Health, College of Medicine, Jordan University of Science and Technology , Irbid, Jordan
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25
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26
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González ME. The HIV-1 Vpr Protein: A Multifaceted Target for Therapeutic Intervention. Int J Mol Sci 2017; 18:ijms18010126. [PMID: 28075409 PMCID: PMC5297760 DOI: 10.3390/ijms18010126] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Revised: 12/22/2016] [Accepted: 01/03/2017] [Indexed: 12/16/2022] Open
Abstract
The human immunodeficiency virus type 1 (HIV-1) Vpr protein is an attractive target for antiretroviral drug development. The conservation both of the structure along virus evolution and the amino acid sequence in viral isolates from patients underlines the importance of Vpr for the establishment and progression of HIV-1 disease. While its contribution to virus replication in dividing and non-dividing cells and to the pathogenesis of HIV-1 in many different cell types, both extracellular and intracellular forms, have been extensively studied, its precise mechanism of action nevertheless remains enigmatic. The present review discusses how the apparently multifaceted interplay between Vpr and host cells may be due to the impairment of basic metabolic pathways. Vpr protein modifies host cell energy metabolism, oxidative status, and proteasome function, all of which are likely conditioned by the concentration and multimerization of the protein. The characterization of Vpr domains along with new laboratory tools for the assessment of their function has become increasingly relevant in recent years. With these advances, it is conceivable that drug discovery efforts involving Vpr-targeted antiretrovirals will experience substantial growth in the coming years.
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Affiliation(s)
- María Eugenia González
- Unidad de Expresión Viral, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Carretera de Majadahonda-Pozuelo Km 2, Majadahonda, 28220 Madrid, Spain.
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27
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Sanjuán R, Domingo-Calap P. Mechanisms of viral mutation. Cell Mol Life Sci 2016; 73:4433-4448. [PMID: 27392606 PMCID: PMC5075021 DOI: 10.1007/s00018-016-2299-6] [Citation(s) in RCA: 497] [Impact Index Per Article: 62.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Revised: 06/20/2016] [Accepted: 06/22/2016] [Indexed: 02/08/2023]
Abstract
The remarkable capacity of some viruses to adapt to new hosts and environments is highly dependent on their ability to generate de novo diversity in a short period of time. Rates of spontaneous mutation vary amply among viruses. RNA viruses mutate faster than DNA viruses, single-stranded viruses mutate faster than double-strand virus, and genome size appears to correlate negatively with mutation rate. Viral mutation rates are modulated at different levels, including polymerase fidelity, sequence context, template secondary structure, cellular microenvironment, replication mechanisms, proofreading, and access to post-replicative repair. Additionally, massive numbers of mutations can be introduced by some virus-encoded diversity-generating elements, as well as by host-encoded cytidine/adenine deaminases. Our current knowledge of viral mutation rates indicates that viral genetic diversity is determined by multiple virus- and host-dependent processes, and that viral mutation rates can evolve in response to specific selective pressures.
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Affiliation(s)
- Rafael Sanjuán
- Department of Genetics and Institute for Integrative Systems Biology (I2SysBio), Universitat de València, C/Catedrático José Beltrán 2, 46980, Paterna, Valencia, Spain.
| | - Pilar Domingo-Calap
- Laboratoire d'ImmunoRhumatologie Moléculaire, INSERM UMR_S1109, LabEx Transplantex, Centre de Recherche d'Immunologie et d'Hématologie, Faculté de Médecine, Fédération de Médecine Translationnelle de Strasbourg (FMTS), Université de Strasbourg, Strasbourg, France
- Fédération Hospitalo-Universitaire OMICARE, Centre de Recherche d'Immunologie et d'Hématologie, Strasbourg, France
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28
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Hansen EC, Ransom M, Hesselberth JR, Hosmane NN, Capoferri AA, Bruner KM, Pollack RA, Zhang H, Drummond MB, Siliciano JM, Siliciano R, Stivers JT. Diverse fates of uracilated HIV-1 DNA during infection of myeloid lineage cells. eLife 2016; 5. [PMID: 27644592 PMCID: PMC5030084 DOI: 10.7554/elife.18447] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Accepted: 08/23/2016] [Indexed: 12/22/2022] Open
Abstract
We report that a major subpopulation of monocyte-derived macrophages (MDMs) contains high levels of dUTP, which is incorporated into HIV-1 DNA during reverse transcription (U/A pairs), resulting in pre-integration restriction and post-integration mutagenesis. After entering the nucleus, uracilated viral DNA products are degraded by the uracil base excision repair (UBER) machinery with less than 1% of the uracilated DNA successfully integrating. Although uracilated proviral DNA showed few mutations, the viral genomic RNA was highly mutated, suggesting that errors occur during transcription. Viral DNA isolated from blood monocytes and alveolar macrophages (but not T cells) of drug-suppressed HIV-infected individuals also contained abundant uracils. The presence of viral uracils in short-lived monocytes suggests their recent infection through contact with virus producing cells in a tissue reservoir. These findings reveal new elements of a viral defense mechanism involving host UBER that may be relevant to the establishment and persistence of HIV-1 infection. DOI:http://dx.doi.org/10.7554/eLife.18447.001 Human immunodeficiency virus type 1 (HIV-1) infects and kills immune cells known as CD4+ T cells, leading to the disease AIDS. Current drug treatments enable HIV-1 infected patients to live relatively long and healthy lives. However, no cure for HIV-1 exists because the virus lives indefinitely in a resting state within the genetic material – or genome – of the infected cell, where it is not susceptible to drug treatments. Most HIV-1 research focuses on T cells, but another type of immune cell – the macrophage – may also harbor resting HIV-1 in its genome. Compared to other cells, macrophages are unusual because they produce large amounts of a molecule called deoxyuridine triphosphate (dUTP). Most cells, including T cells, keep dUTP levels very low because it closely resembles molecules that are used to make DNA and so it can be accidentally incorporated into the cell’s DNA. When this happens, the cell removes the dUTP from the DNA using enzymes in a process called uracil base excision repair (UBER). To hide inside the cell’s genome, HIV-1 needs to produce a DNA copy of its own genome, but it was not known what happens when HIV-1 tries to do this within a macrophage that contains high levels of dUTP and UBER enzymes. Here, Hansen et al. reveal that about 90% of macrophages have exceptionally high levels of dUTP and are poorly infected by HIV-1. The high levels of dUTP result in the virus incorporating dUTP into its DNA, which is then attacked and fragmented by UBER enzymes. However, about one in a hundred viral DNA molecules do manage to successfully integrate into the genome of the macrophage. This viral DNA later gives rise to new virus particles through an error-prone process that, by introducing new mutations into the virus genome, may help HIV-1 to evolve and persist. Further experiments examined cells that give rise to macrophages from infected patients who had been on anti-HIV drug therapy for several years. Hansen et al. found that there was lots of dUTP in the DNA sequences of HIV-1 viruses found in these “precursor” cells. These precursor cells only live for several days before being eliminated, so the presence of viruses containing dUTP suggests these cells were infected recently. A future challenge will be to identify new anti-HIV drugs that specifically target macrophages and to understand the role of error-prone production of new viral genomes. DOI:http://dx.doi.org/10.7554/eLife.18447.002
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Affiliation(s)
- Erik C Hansen
- Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, United States
| | - Monica Ransom
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, United States
| | - Jay R Hesselberth
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, United States
| | - Nina N Hosmane
- Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, United States
| | - Adam A Capoferri
- Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, United States.,Howard Hughes Medical Institute, The Johns Hopkins School of Medicine, Baltimore, United States
| | - Katherine M Bruner
- Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, United States
| | - Ross A Pollack
- Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, United States
| | - Hao Zhang
- W Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, United States
| | - Michael Bradley Drummond
- Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, United States
| | - Janet M Siliciano
- Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, United States
| | - Robert Siliciano
- Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, United States.,Howard Hughes Medical Institute, The Johns Hopkins School of Medicine, Baltimore, United States
| | - James T Stivers
- Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, United States
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29
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Wu Y, Zhou X, Barnes CO, DeLucia M, Cohen AE, Gronenborn AM, Ahn J, Calero G. The DDB1-DCAF1-Vpr-UNG2 crystal structure reveals how HIV-1 Vpr steers human UNG2 toward destruction. Nat Struct Mol Biol 2016; 23:933-940. [PMID: 27571178 DOI: 10.1038/nsmb.3284] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Accepted: 08/03/2016] [Indexed: 01/04/2023]
Abstract
The HIV-1 accessory protein Vpr is required for efficient viral infection of macrophages and promotion of viral replication in T cells. Vpr's biological activities are closely linked to the interaction with human DCAF1, a cellular substrate receptor of the Cullin4-RING E3 ubiquitin ligase (CRL4) of the host ubiquitin-proteasome-mediated protein degradation pathway. The molecular details of how Vpr usurps the protein degradation pathway have not been delineated. Here we present the crystal structure of the DDB1-DCAF1-HIV-1-Vpr-uracil-DNA glycosylase (UNG2) complex. The structure reveals how Vpr engages with DCAF1, creating a binding interface for UNG2 recruitment in a manner distinct from the recruitment of SAMHD1 by Vpx proteins. Vpr and Vpx use similar N-terminal and helical regions to bind the substrate receptor, whereas different regions target the specific cellular substrates. Furthermore, Vpr uses molecular mimicry of DNA by a variable loop for specific recruitment of the UNG2 substrate.
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Affiliation(s)
- Ying Wu
- Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.,Department of Structural Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Xiaohong Zhou
- Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.,Department of Structural Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Christopher O Barnes
- Department of Structural Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.,Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Maria DeLucia
- Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.,Department of Structural Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Aina E Cohen
- Stanford Synchrotron Radiation Lightsource, Stanford University, Menlo Park, California, USA
| | - Angela M Gronenborn
- Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.,Department of Structural Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Jinwoo Ahn
- Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.,Department of Structural Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Guillermo Calero
- Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.,Department of Structural Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
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30
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Datta PK, Deshmane S, Khalili K, Merali S, Gordon JC, Fecchio C, Barrero CA. Glutamate metabolism in HIV-1 infected macrophages: Role of HIV-1 Vpr. Cell Cycle 2016; 15:2288-98. [PMID: 27245560 DOI: 10.1080/15384101.2016.1190054] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
HIV-1 infected macrophages play a significant role in the neuropathogenesis of AIDS. HIV-1 viral protein R (Vpr) not only facilitates HIV-1 infection but also contribute to long-lived persistence in macrophages. Our previous studies using SILAC-based proteomic analysis showed that the expression of critical metabolic enzymes in the glycolytic pathway and tricarboxylic acid (TCA) cycle were altered in response to Vpr expression in macrophages. We hypothesized that Vpr-induced modulation of glycolysis and TCA cycle regulates glutamate metabolism and release in HIV-1 infected macrophages. We assessed the amount of specific metabolites induced by Vpr and HIV-1 in macrophages at the intracellular and extracellular level in a time-dependent manner utilizing multiple reaction monitoring (MRM) targeted metabolomics. In addition, stable isotope-labeled glucose and an MRM targeted metabolomics assay were used to evaluate the de novo synthesis and release of glutamate in Vpr overexpressing macrophages and HIV-1 infected macrophages, throughout the metabolic flux of glycolytic pathway and TCA cycle activation. The metabolic flux studies demonstrated an increase in glucose uptake, glutamate release and accumulation of α-ketoglutarate (α-KG) and glutamine in the extracellular milieu in Vpr expressing and HIV-1 infected macrophages. Interestingly, glutamate pools and other intracellular intermediates (glucose-6-phosphate (G6P), fructose-6-phosphate (F6P), citrate, malate, α-KG, and glutamine) showed a decreased trend except for fumarate, in contrast to the glutamine accumulation observed in the extracellular space in Vpr overexpressing macrophages. Our studies demonstrate that dysregulation of mitochondrial glutamate metabolism induced by Vpr in HIV-1 infected macrophages commonly seen, may contribute to neurodegeneration via excitotoxic mechanisms in the context of NeuroAIDS.
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Affiliation(s)
- Prasun K Datta
- a Department of Neuroscience and Comprehensive NeuroAIDS Center , Lewis Katz School of Medicine at Temple University , Philadelphia , PA , USA
| | - Satish Deshmane
- a Department of Neuroscience and Comprehensive NeuroAIDS Center , Lewis Katz School of Medicine at Temple University , Philadelphia , PA , USA
| | - Kamel Khalili
- a Department of Neuroscience and Comprehensive NeuroAIDS Center , Lewis Katz School of Medicine at Temple University , Philadelphia , PA , USA
| | - Salim Merali
- a Department of Neuroscience and Comprehensive NeuroAIDS Center , Lewis Katz School of Medicine at Temple University , Philadelphia , PA , USA.,b Department of Pharmaceutical Sciences and Moulder Center for Drug Discovery Research , Temple University School of Pharmacy , Philadelphia , PA , USA
| | - John C Gordon
- b Department of Pharmaceutical Sciences and Moulder Center for Drug Discovery Research , Temple University School of Pharmacy , Philadelphia , PA , USA
| | - Chiara Fecchio
- b Department of Pharmaceutical Sciences and Moulder Center for Drug Discovery Research , Temple University School of Pharmacy , Philadelphia , PA , USA
| | - Carlos A Barrero
- a Department of Neuroscience and Comprehensive NeuroAIDS Center , Lewis Katz School of Medicine at Temple University , Philadelphia , PA , USA.,b Department of Pharmaceutical Sciences and Moulder Center for Drug Discovery Research , Temple University School of Pharmacy , Philadelphia , PA , USA
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31
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Herate C, Vigne C, Guenzel CA, Lambele M, Rouyez MC, Benichou S. Uracil DNA glycosylase interacts with the p32 subunit of the replication protein A complex to modulate HIV-1 reverse transcription for optimal virus dissemination. Retrovirology 2016; 13:26. [PMID: 27068393 PMCID: PMC4828845 DOI: 10.1186/s12977-016-0257-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Accepted: 03/27/2016] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND Through incorporation into virus particles, the HIV-1 Vpr protein participates in the early steps of the virus life cycle by influencing the reverse transcription process. We previously showed that this positive impact on reverse transcription was related to Vpr binding to the uracil DNA glycosylase 2 enzyme (UNG2), leading to enhancement of virus infectivity in established CD4-positive cell lines via a nonenzymatic mechanism. RESULTS We report here that Vpr can form a trimolecular complex with UNG2 and the p32 subunit (RPA32) of the replication protein A (RPA) complex and we explore how these cellular proteins can influence virus replication and dissemination in the primary target cells of HIV-1, which express low levels of both proteins. Virus infectivity and replication in peripheral blood mononuclear cells and monocyte-derived macrophages (MDMs), as well as the efficiency of the viral DNA synthesis, were significantly reduced when viruses were produced from cells depleted of endogenous UNG2 or RPA32. Moreover, viruses produced in macrophages failed to replicate efficiently in UNG2- and RPA32-depleted T lymphocytes. Reciprocally, viruses produced in UNG2-depleted T cells did not replicate efficiently in MDMs confirming the positive role of UNG2 for virus dissemination. CONCLUSIONS Our data show the positive effect of UNG2 and RPA32 on the reverse transcription process leading to optimal virus replication and dissemination between the primary target cells of HIV-1.
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Affiliation(s)
- Cecile Herate
- />Inserm U1016, Institut Cochin, 22 Rue Méchain, 75014 Paris, France
- />CNRS, UMR8104, Paris, France
- />Université Paris-Descartes, Sorbonne Paris-Cité, Paris, France
| | - Clarisse Vigne
- />Inserm U1016, Institut Cochin, 22 Rue Méchain, 75014 Paris, France
- />CNRS, UMR8104, Paris, France
- />Université Paris-Descartes, Sorbonne Paris-Cité, Paris, France
| | - Carolin A. Guenzel
- />Inserm U1016, Institut Cochin, 22 Rue Méchain, 75014 Paris, France
- />CNRS, UMR8104, Paris, France
- />Université Paris-Descartes, Sorbonne Paris-Cité, Paris, France
| | - Marie Lambele
- />Inserm U1016, Institut Cochin, 22 Rue Méchain, 75014 Paris, France
- />CNRS, UMR8104, Paris, France
- />Université Paris-Descartes, Sorbonne Paris-Cité, Paris, France
| | - Marie-Christine Rouyez
- />Inserm U1016, Institut Cochin, 22 Rue Méchain, 75014 Paris, France
- />CNRS, UMR8104, Paris, France
- />Université Paris-Descartes, Sorbonne Paris-Cité, Paris, France
| | - Serge Benichou
- />Inserm U1016, Institut Cochin, 22 Rue Méchain, 75014 Paris, France
- />CNRS, UMR8104, Paris, France
- />Université Paris-Descartes, Sorbonne Paris-Cité, Paris, France
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32
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Abstract
The enzyme reverse transcriptase (RT) was discovered in retroviruses almost 50 years ago. The demonstration that other types of viruses, and what are now called retrotransposons, also replicated using an enzyme that could copy RNA into DNA came a few years later. The intensity of the research in both the process of reverse transcription and the enzyme RT was greatly stimulated by the recognition, in the mid-1980s, that human immunodeficiency virus (HIV) was a retrovirus and by the fact that the first successful anti-HIV drug, azidothymidine (AZT), is a substrate for RT. Although AZT monotherapy is a thing of the past, the most commonly prescribed, and most successful, combination therapies still involve one or both of the two major classes of anti-RT drugs. Although the basic mechanics of reverse transcription were worked out many years ago, and the first high-resolution structures of HIV RT are now more than 20 years old, we still have much to learn, particularly about the roles played by the host and viral factors that make the process of reverse transcription much more efficient in the cell than in the test tube. Moreover, we are only now beginning to understand how various host factors that are part of the innate immunity system interact with the process of reverse transcription to protect the host-cell genome, the host cell, and the whole host, from retroviral infection, and from unwanted retrotransposition.
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33
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Rawson JMO, Clouser CL, Mansky LM. Rapid Determination of HIV-1 Mutant Frequencies and Mutation Spectra Using an mCherry/EGFP Dual-Reporter Viral Vector. Methods Mol Biol 2016; 1354:71-88. [PMID: 26714706 DOI: 10.1007/978-1-4939-3046-3_6] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
The high mutation rate of human immunodeficiency virus type-1 (HIV-1) has been a pivotal factor in its evolutionary success as a human pathogen, driving the emergence of drug resistance, immune system escape, and invasion of distinct anatomical compartments. Extensive research has focused on understanding how various cellular and viral factors alter the rates and types of mutations produced during viral replication. Here, we describe a single-cycle dual-reporter vector assay that relies upon the detection of mutations that eliminate either expression of mCherry or enhanced green fluorescent protein (EGFP). The reporter-based method can be used to efficiently quantify changes in mutant frequencies and mutation spectra that arise due to a variety of factors, including viral mutagens, drug resistance mutations, cellular physiology, and APOBEC3 proteins.
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Affiliation(s)
- Jonathan M O Rawson
- Institute for Molecular Virology, University of Minnesota, Minneapolis, MN, 55455, USA
- Molecular, Cellular, Developmental Biology & Genetics Graduate Program, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Christine L Clouser
- Institute for Molecular Virology, University of Minnesota, Minneapolis, MN, 55455, USA
- Department of Diagnostic and Biological Sciences, School of Dentistry, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Louis M Mansky
- Institute for Molecular Virology, University of Minnesota, Minneapolis, MN, 55455, USA.
- Molecular, Cellular, Developmental Biology & Genetics Graduate Program, University of Minnesota, Minneapolis, MN, 55455, USA.
- Department of Diagnostic and Biological Sciences, School of Dentistry, University of Minnesota, Minneapolis, MN, 55455, USA.
- Department of Microbiology, University of Minnesota, Graduate Program, Mayo Mail Code 196, 1460 Mayo Building, 420 Delaware Street SE, Minneapolis, MN, 55455, USA.
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34
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Romani B, Baygloo NS, Hamidi-Fard M, Aghasadeghi MR, Allahbakhshi E. HIV-1 Vpr Protein Induces Proteasomal Degradation of Chromatin-associated Class I HDACs to Overcome Latent Infection of Macrophages. J Biol Chem 2015; 291:2696-711. [PMID: 26679995 DOI: 10.1074/jbc.m115.689018] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2015] [Indexed: 11/06/2022] Open
Abstract
Mechanisms underlying HIV-1 latency remain among the most crucial questions that need to be answered to adopt strategies for purging the latent viral reservoirs. Here we show that HIV-1 accessory protein Vpr induces depletion of class I HDACs, including HDAC1, 2, 3, and 8, to overcome latency in macrophages. We found that Vpr binds and depletes chromatin-associated class I HDACs through a VprBP-dependent mechanism, with HDAC3 as the most affected class I HDAC. De novo expression of Vpr in infected macrophages induced depletion of HDAC1 and 3 on the HIV-1 LTR that was associated with hyperacetylation of histones on the HIV-1 LTR. As a result of hyperacetylation of histones on HIV-1 promotor, the virus established an active promotor and this contributed to the acute infection of macrophages. Collectively, HIV-1 Vpr down-regulates class I HDACs on chromatin to counteract latent infections of macrophages.
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Affiliation(s)
- Bizhan Romani
- From the Department of Biology, Faculty of Science, University of Isfahan, Isfahan 81746-73441, Iran, Cellular and Molecular Research Center (CMRC), Faculty of Medicine, Ahvaz Jundishapur University of Medical Sciences (AJUMS), Ahvaz 61357-15794, Iran, and
| | - Nima Shaykh Baygloo
- From the Department of Biology, Faculty of Science, University of Isfahan, Isfahan 81746-73441, Iran
| | - Mojtaba Hamidi-Fard
- Hepatitis and AIDS Department, Pasteur Institute of Iran, Tehran 13169-43551, Iran
| | | | - Elham Allahbakhshi
- Cellular and Molecular Research Center (CMRC), Faculty of Medicine, Ahvaz Jundishapur University of Medical Sciences (AJUMS), Ahvaz 61357-15794, Iran, and
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35
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Vpr Enhances Tumor Necrosis Factor Production by HIV-1-Infected T Cells. J Virol 2015; 89:12118-30. [PMID: 26401039 DOI: 10.1128/jvi.02098-15] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Accepted: 09/16/2015] [Indexed: 02/06/2023] Open
Abstract
UNLABELLED The HIV-1 accessory protein Vpr displays different activities potentially impacting viral replication, including the arrest of the cell cycle in the G2 phase and the stimulation of apoptosis and DNA damage response pathways. Vpr also modulates cytokine production by infected cells, but this property remains partly characterized. Here, we investigated the effect of Vpr on the production of the proinflammatory cytokine tumor necrosis factor (TNF). We report that Vpr significantly increases TNF secretion by infected lymphocytes. De novo production of Vpr is required for this effect. Vpr mutants known to be defective for G2 cell cycle arrest induce lower levels of TNF secretion, suggesting a link between these two functions. Silencing experiments and the use of chemical inhibitors further implicated the cellular proteins DDB1 and TAK1 in this activity of Vpr. TNF secreted by HIV-1-infected cells triggers NF-κB activity in bystander cells and allows viral reactivation in a model of latently infected cells. Thus, the stimulation of the proinflammatory pathway by Vpr may impact HIV-1 replication in vivo. IMPORTANCE The role of the HIV-1 accessory protein Vpr remains only partially characterized. This protein is important for viral pathogenesis in infected individuals but is dispensable for viral replication in most cell culture systems. Some of the functions described for Vpr remain controversial. In particular, it remains unclear whether Vpr promotes or instead prevents proinflammatory and antiviral immune responses. In this report, we show that Vpr promotes the release of TNF, a proinflammatory cytokine associated with rapid disease progression. Using Vpr mutants or inhibiting selected cellular genes, we show that the cellular proteins DDB1 and TAK1 are involved in the release of TNF by HIV-infected cells. This report provides novel insights into how Vpr manipulates TNF production and helps clarify the role of Vpr in innate immune responses and inflammation.
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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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Rawson JMO, Mansky LM. Retroviral vectors for analysis of viral mutagenesis and recombination. Viruses 2014; 6:3612-42. [PMID: 25254386 PMCID: PMC4189041 DOI: 10.3390/v6093612] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2014] [Revised: 09/15/2014] [Accepted: 09/17/2014] [Indexed: 12/29/2022] Open
Abstract
Retrovirus population diversity within infected hosts is commonly high due in part to elevated rates of replication, mutation, and recombination. This high genetic diversity often complicates the development of effective diagnostics, vaccines, and antiviral drugs. This review highlights the diverse vectors and approaches that have been used to examine mutation and recombination in retroviruses. Retroviral vectors for these purposes can broadly be divided into two categories: those that utilize reporter genes as mutation or recombination targets and those that utilize viral genes as targets of mutation or recombination. Reporter gene vectors greatly facilitate the detection, quantification, and characterization of mutants and/or recombinants, but may not fully recapitulate the patterns of mutagenesis or recombination observed in native viral gene sequences. In contrast, the detection of mutations or recombination events directly in viral genes is more biologically relevant but also typically more challenging and inefficient. We will highlight the advantages and disadvantages of the various vectors and approaches used as well as propose ways in which they could be improved.
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Affiliation(s)
- Jonathan M O Rawson
- Institute for Molecular Virology, University of Minnesota, Moos Tower 18-242, 515 Delaware St SE, Minneapolis, MN 55455, USA.
| | - Louis M Mansky
- Institute for Molecular Virology, University of Minnesota, Moos Tower 18-242, 515 Delaware St SE, Minneapolis, MN 55455, USA.
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The HIV-1 accessory protein Vpr induces the degradation of the anti-HIV-1 agent APOBEC3G through a VprBP-mediated proteasomal pathway. Virus Res 2014; 195:25-34. [PMID: 25200749 DOI: 10.1016/j.virusres.2014.08.021] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Revised: 08/28/2014] [Accepted: 08/28/2014] [Indexed: 12/31/2022]
Abstract
The host anti-HIV-1 factor APOBEC3G (A3G) plays a potential role in restricting HIV-1 replication, although this antagonist can be encountered and disarmed by the Vif protein. In this paper, we report that another HIV-1 accessory protein, viral protein R (Vpr), can interact with A3G and intervene in its antiviral behavior. The interaction of Vpr and A3G was predicted by computer-based screen and confirmed by a co-immunoprecipitation (Co-IP) approach. We found that Vpr could reduce the virion encapsidation of A3G to enhance viral replication. Subsequent experiments showed that Vpr downregulated A3G through Vpr-binding protein (VprBP)-mediated proteasomal degradation, and further confirmed that the reduction of A3G encapsidation associated with Vpr was due to Vpr's degradation-inducing activity. Our findings highlight the versatility of Vpr by unveiling the hostile relationship between Vpr and A3G. In addition, the observation that A3G is targeted to the proteasomal degradation pathway by Vpr in addition to Vif implicates the existence of crosstalk between different HIV-1-host ubiquitin ligase complex systems.
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Abstract
UNLABELLED HIV-1 modulates key host cellular pathways for successful replication and pathogenesis through viral proteins. By evaluating the hijacking of the host ubiquitination pathway by HIV-1 at the whole-cell level, we now show major perturbations in the ubiquitinated pool of the host proteins post-HIV-1 infection. Our overexpression- and infection-based studies of T cells with wild-type and mutant HIV-1 proviral constructs showed that Vpr is necessary and sufficient for reducing whole-cell ubiquitination. Mutagenic analysis revealed that the three leucine-rich helical regions of Vpr are critical for this novel function of Vpr, which was independent of its other known cellular functions. We also validated that this effect of Vpr was conserved among different subtypes (subtypes B and C) and circulating recombinants from Northern India. Finally, we establish that this phenomenon is involved in HIV-1-mediated diversion of host ubiquitination machinery specifically toward the degradation of various restriction factors during viral pathogenesis. IMPORTANCE HIV-1 is known to rely heavily on modulation of the host ubiquitin pathway, particularly for counteraction of antiretroviral restriction factors, i.e., APOBEC3G, UNG2, and BST-2, etc.; viral assembly; and release. Reports to date have focused on the molecular hijacking of the ubiquitin machinery by HIV-1 at the level of E3 ligases. Interaction of a viral protein with an E3 ligase alters its specificity to bring about selective protein ubiquitination. However, in the case of infection, multiple viral proteins can interact with this multienzyme pathway at various levels, making it much more complicated. Here, we have addressed the manipulation of ubiquitination at the whole-cell level post-HIV-1 infection. Our results show that HIV-1 Vpr is necessary and sufficient to bring about the redirection of the host ubiquitin pathway toward HIV-1-specific outcomes. We also show that the three leucine-rich helical regions of Vpr are critical for this effect and that this ability of Vpr is conserved across circulating recombinants. Our work, the first of its kind, provides novel insight into the regulation of the ubiquitin system at the whole-cell level by HIV-1.
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Guenzel CA, Hérate C, Benichou S. HIV-1 Vpr-a still "enigmatic multitasker". Front Microbiol 2014; 5:127. [PMID: 24744753 PMCID: PMC3978352 DOI: 10.3389/fmicb.2014.00127] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2013] [Accepted: 03/12/2014] [Indexed: 11/13/2022] Open
Abstract
Like other HIV-1 auxiliary proteins, Vpr is conserved within all the human (HIV-1, HIV-2) and simian (SIV) immunodeficiency viruses. However, Vpr and homologous HIV-2, and SIV Vpx are the only viral auxiliary proteins specifically incorporated into virus particles through direct interaction with the Gag precursor, indicating that this presence in the core of the mature virions is mainly required for optimal establishment of the early steps of the virus life cycle in the newly infected cell. In spite of its small size, a plethora of effects and functions have been attributed to Vpr, including induction of cell cycle arrest and apoptosis, modulation of the fidelity of reverse transcription, nuclear import of viral DNA in macrophages and other non-dividing cells, and transcriptional modulation of viral and host cell genes. Even if some more recent studies identified a few cellular targets that HIV-1 Vpr may utilize in order to perform its different tasks, the real role and functions of Vpr during the course of natural infection are still enigmatic. In this review, we will summarize the main reported functions of HIV-1 Vpr and their significance in the context of the viral life cycle.
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Affiliation(s)
- Carolin A Guenzel
- Cochin Institute, INSERM U1016, Centre National de la Recherche Scientifique UMR8104, Université Paris-Descartes Paris, France
| | - Cécile Hérate
- Cochin Institute, INSERM U1016, Centre National de la Recherche Scientifique UMR8104, Université Paris-Descartes Paris, France
| | - Serge Benichou
- Cochin Institute, INSERM U1016, Centre National de la Recherche Scientifique UMR8104, Université Paris-Descartes Paris, France
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Nekorchuk MD, Sharifi HJ, Furuya AKM, Jellinger R, de Noronha CMC. HIV relies on neddylation for ubiquitin ligase-mediated functions. Retrovirology 2013; 10:138. [PMID: 24245672 PMCID: PMC3842660 DOI: 10.1186/1742-4690-10-138] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2013] [Accepted: 11/07/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND HIV and SIV defeat antiviral proteins by usurping Cullin-RING E3 ubiquitin ligases (CRLs) and likely influence other cellular processes through these as well. HIV-2 viral protein X (Vpx) engages the cullin4-containing CRL4 complex to deplete the antiviral protein SAMHD1. Vif expressed by HIV-1 and HIV-2 taps a cullin5 ubiquitin ligase complex to mark the antiviral protein APOBEC3G for destruction. Viral Protein R of HIV-1 (Vpr) assembles with the CRL4 ubiquitin ligase complex to deplete uracil-N-glycosylase2 (UNG2). Covalent attachment of the ubiquitin-like protein side-chain NEDD8 functionally activates cullins which are common to all of these processes. RESULTS The requirement for neddylation in HIV-1 and HIV-2 infectivity was tested in the presence of APOBEC3G and SAMHD1 respectively. Further the need for neddylation in HIV-1 Vpr-mediated depletion of UNG2 was probed. Treatment with MLN4924, an adenosine sulfamate analog which hinders the NEDD8 activating enzyme NAE1, blocked neddylation of cullin4A (CUL4A). The inhibitor hindered HIV-1 infection in the presence of APOBEC3G, even when Vif was expressed, and it stopped HIV-2 infection in the presence of SAMHD1 and Vpx. Consistent with these findings, MLN4924 prevented Vpx-mediated depletion of SAMHD1 in macrophages infected with Vpx-expressing HIV-2, as well as HIV-1 Vif-mediated destruction of APOBEC3G. It also stemmed Vpr-mediated UNG2 elimination from cells infected with HIV-1. CONCLUSIONS Neddylation plays an important role in HIV-1 and HIV-2 infection. This observation is consistent with the essential parts that cullin-based ubiquitin ligases play in overcoming cellular anti-viral defenses.
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Affiliation(s)
| | | | | | | | - Carlos M C de Noronha
- Center for Immunology and Microbial Disease, Albany Medical College, 43 New Scotland Avenue, Albany, NY 12208, USA.
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42
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Eldin P, Chazal N, Fenard D, Bernard E, Guichou JF, Briant L. Vpr expression abolishes the capacity of HIV-1 infected cells to repair uracilated DNA. Nucleic Acids Res 2013; 42:1698-710. [PMID: 24178031 PMCID: PMC3919559 DOI: 10.1093/nar/gkt974] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
The human immunodeficiency virus type 1 (HIV-1) Vpr protein binds to the cellular uracil–DNA glycosylase UNG2 and induces its degradation through the assembly with the DDB1-CUL4 ubiquitin ligase complex. This interaction counteracts the antiviral activity exerted by UNG2 on HIV-1 gene transcription, as previously reported by us. In this work, we show that Vpr expression in the context of HIV-1 infection markedly decreases UNG2 expression in transformed or primary CD4+ T lymphocytes. We demonstrate for the first time that Vpr-UNG2 interaction significantly impairs the uracil excision activity of infected cells. The loss of uracil excision activity coincides with a significant accumulation of uracilated bases in the genome of infected cells without changes in cell division. Although UNG2 expression and uracil–DNA glycosylase activity are recovered after the peak of retroviral replication, the mutagenic effect of transient DNA uracilation in cycling cells should be taken into account. Therefore, the possible consequences of Vpr-mediated temporary depletion of endogenous nuclear UNG2 and subsequent alteration of the genomic integrity of infected cells need to be evaluated in the physiopathogenesis of HIV infection.
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Affiliation(s)
- Patrick Eldin
- Centre d'étude d'agents Pathogènes et Biotechnologies pour la Santé (CPBS) - UMR 5236-CNRS - Université Montpellier 1 and 2, Montpellier, France and Centre de Biochimie Structurale, INSERM U1054, CNRS UMR5048, Université Montpellier 1 and 2, Montpellier, France
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Casey Klockow L, Sharifi HJ, Wen X, Flagg M, Furuya AKM, Nekorchuk M, de Noronha CMC. The HIV-1 protein Vpr targets the endoribonuclease Dicer for proteasomal degradation to boost macrophage infection. Virology 2013; 444:191-202. [PMID: 23849790 DOI: 10.1016/j.virol.2013.06.010] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Accepted: 06/09/2013] [Indexed: 12/13/2022]
Abstract
The HIV-1 protein Vpr enhances macrophage infection, triggers G2 cell cycle arrest, and targets cells for NK-cell killing. Vpr acts through the CRL4(DCAF1) ubiquitin ligase complex to cause G2 arrest and trigger expression of NK ligands. Corresponding ubiquitination targets have not been identified. UNG2 and SMUG1 are the only known substrates for Vpr-directed depletion through CRL4(DCAF1). Here we identify the endoribonuclease Dicer as a target of HIV-1 Vpr-directed proteasomal degradation through CRL4(DCAF1). We show that HIV-1 Vpr inhibits short hairpin RNA function as expected upon reduction of Dicer levels. Dicer inhibits HIV-1 replication in T cells. We demonstrate that Dicer also restricts HIV-1 replication in human monocyte-derived macrophages (MDM) and that reducing Dicer expression in MDMs enhances HIV-1 infection in a Vpr-dependent manner. Our results support a model in which Vpr complexes with human Dicer to boost its interaction with the CRL4(DCAF1) ubiquitin ligase complex and its subsequent degradation.
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Affiliation(s)
- Laurieann Casey Klockow
- Center for Immunology and Microbial Disease, Albany Medical College, 47 New Scotland Avenue, Albany, NY 12208, USA
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Iordanskiy S, Santos S, Bukrinsky M. Nature, nurture and HIV: The effect of producer cell on viral physiology. Virology 2013; 443:208-13. [PMID: 23747196 DOI: 10.1016/j.virol.2013.05.023] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2013] [Revised: 04/23/2013] [Accepted: 05/15/2013] [Indexed: 01/13/2023]
Abstract
Macrophages and CD4-positive T lymphocytes are the major targets and producers of HIV-1. While the molecular details underlying HIV replication in macrophages and T cells become better understood, it remains unclear whether viruses produced by these target cells differ in their biological properties. Recent reports suggest that HIV virions incorporate a large number of producer cell proteins and lipids which have an effect on subsequent viral replication in newly infected cells. The identity and abundance of these incorporated factors varies between different types of producer cells, suggesting that they may influence the replication capacity and pathogenic activity of the virions produced by T cells and macrophages.
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Affiliation(s)
- Sergey Iordanskiy
- Department of Microbiology, Immunology and Tropical Medicine, School of Medicine and Health Sciences, George Washington University, 2300 I Street NW, Ross Hall, Washington, DC 20037, USA.
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45
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Kitamura K, Wang Z, Chowdhury S, Simadu M, Koura M, Muramatsu M. Uracil DNA glycosylase counteracts APOBEC3G-induced hypermutation of hepatitis B viral genomes: excision repair of covalently closed circular DNA. PLoS Pathog 2013; 9:e1003361. [PMID: 23696735 PMCID: PMC3656096 DOI: 10.1371/journal.ppat.1003361] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2012] [Accepted: 03/31/2013] [Indexed: 12/17/2022] Open
Abstract
The covalently closed circular DNA (cccDNA) of the hepatitis B virus (HBV) plays an essential role in chronic hepatitis. The cellular repair system is proposed to convert cytoplasmic nucleocapsid (NC) DNA (partially double-stranded DNA) into cccDNA in the nucleus. Recently, antiviral cytidine deaminases, AID/APOBEC proteins, were shown to generate uracil residues in the NC-DNA through deamination, resulting in cytidine-to-uracil (C-to-U) hypermutation of the viral genome. We investigated whether uracil residues in hepadnavirus DNA were excised by uracil-DNA glycosylase (UNG), a host factor for base excision repair (BER). When UNG activity was inhibited by the expression of the UNG inhibitory protein (UGI), hypermutation of NC-DNA induced by either APOBEC3G or interferon treatment was enhanced in a human hepatocyte cell line. To assess the effect of UNG on the cccDNA viral intermediate, we used the duck HBV (DHBV) replication model. Sequence analyses of DHBV DNAs showed that cccDNA accumulated G-to-A or C-to-T mutations in APOBEC3G-expressing cells, and this was extensively enhanced by UNG inhibition. The cccDNA hypermutation generated many premature stop codons in the P gene. UNG inhibition also enhanced the APOBEC3G-mediated suppression of viral replication, including reduction of NC-DNA, pre-C mRNA, and secreted viral particle-associated DNA in prolonged culture. Enhancement of APOBEC3G-mediated suppression by UNG inhibition was not observed when the catalytic site of APOBEC3G was mutated. Transfection experiments of recloned cccDNAs revealed that the combination of UNG inhibition and APOBEC3G expression reduced the replication ability of cccDNA. Taken together, these data indicate that UNG excises uracil residues from the viral genome during or after cccDNA formation in the nucleus and imply that BER pathway activities decrease the antiviral effect of APOBEC3-mediated hypermutation.
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Affiliation(s)
- Kouichi Kitamura
- Department of Molecular Genetics, Kanazawa University Graduate School of Medical Science, Kanazawa, Japan
| | - Zhe Wang
- Department of Molecular Genetics, Kanazawa University Graduate School of Medical Science, Kanazawa, Japan
| | - Sajeda Chowdhury
- Department of Molecular Genetics, Kanazawa University Graduate School of Medical Science, Kanazawa, Japan
| | - Miyuki Simadu
- Department of Molecular Genetics, Kanazawa University Graduate School of Medical Science, Kanazawa, Japan
| | - Miki Koura
- Department of Molecular Genetics, Kanazawa University Graduate School of Medical Science, Kanazawa, Japan
| | - Masamichi Muramatsu
- Department of Molecular Genetics, Kanazawa University Graduate School of Medical Science, Kanazawa, Japan
- * E-mail:
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DeLucia M, Mehrens J, Wu Y, Ahn J. HIV-2 and SIVmac accessory virulence factor Vpx down-regulates SAMHD1 enzyme catalysis prior to proteasome-dependent degradation. J Biol Chem 2013; 288:19116-26. [PMID: 23677995 DOI: 10.1074/jbc.m113.469007] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
SAMHD1, a dGTP-regulated deoxyribonucleoside triphosphate (dNTP) triphosphohydrolase, down-regulates dNTP pools in terminally differentiated and quiescent cells, thereby inhibiting HIV-1 infection at the reverse transcription step. HIV-2 and simian immunodeficiency virus (SIV) counteract this restriction via a virion-associated virulence accessory factor, Vpx (Vpr in some SIVs), which loads SAMHD1 onto CRL4-DCAF1 E3 ubiquitin ligase for polyubiquitination, programming it for proteasome-dependent degradation. However, the detailed molecular mechanisms of SAMHD1 recruitment to the E3 ligase have not been defined. Further, whether divergent, orthologous Vpx proteins, encoded by distinct HIV/SIV strains, bind SAMHD1 in a similar manner, at a molecular level, is not known. We applied surface plasmon resonance analysis to assess the requirements for and kinetics of binding between various primate SAMHD1 proteins and Vpx proteins from SIV or HIV-2 strains. Our data indicate that Vpx proteins, bound to DCAF1, interface with the C terminus of primate SAMHD1 proteins with nanomolar affinity, manifested by rapid association and slow dissociation. Further, we provide evidence that Vpx binding to SAMHD1 inhibits its catalytic activity and induces disassembly of a dGTP-dependent oligomer. Our studies reveal a previously unrecognized biochemical mechanism of Vpx-mediated SAMHD1 inhibition: direct down-modulation of its catalytic activity, mediated by the same binding event that leads to SAMHD1 recruitment to the E3 ubiquitin ligase for proteasome-dependent degradation.
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Affiliation(s)
- Maria DeLucia
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15260, USA
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47
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Uracil DNA glycosylase initiates degradation of HIV-1 cDNA containing misincorporated dUTP and prevents viral integration. Proc Natl Acad Sci U S A 2013; 110:E448-57. [PMID: 23341616 DOI: 10.1073/pnas.1219702110] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
HIV-1 reverse transcriptase discriminates poorly between dUTP and dTTP, and accordingly, viral DNA products become heavily uracilated when viruses infect host cells that contain high ratios of dUTP:dTTP. Uracilation of invading retroviral DNA is thought to be an innate immunity barrier to retroviral infection, but the mechanistic features of this immune pathway and the cellular fate of uracilated retroviral DNA products is not known. Here we developed a model system in which the cellular dUTP:dTTP ratio can be pharmacologically increased to favor dUTP incorporation, allowing dissection of this innate immunity pathway. When the virus-infected cells contained elevated dUTP levels, reverse transcription was found to proceed unperturbed, but integration and viral protein expression were largely blocked. Furthermore, successfully integrated proviruses lacked detectable uracil, suggesting that only nonuracilated viral DNA products were integration competent. Integration of the uracilated proviruses was restored using an isogenic cell line that had no detectable human uracil DNA glycosylase (hUNG2) activity, establishing that hUNG2 is a host restriction factor in cells that contain high dUTP. Biochemical studies in primary cells established that this immune pathway is not operative in CD4+ T cells, because these cells have high dUTPase activity (low dUTP), and only modest levels of hUNG activity. Although monocyte-derived macrophages have high dUTP levels, these cells have low hUNG activity, which may diminish the effectiveness of this restriction pathway. These findings establish the essential elements of this pathway and reconcile diverse observations in the literature.
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48
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Molecular mechanisms of HIV immune evasion of the innate immune response in myeloid cells. Viruses 2012; 5:1-14. [PMID: 23344558 PMCID: PMC3564108 DOI: 10.3390/v5010001] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2012] [Revised: 12/19/2012] [Accepted: 12/19/2012] [Indexed: 12/13/2022] Open
Abstract
The expression of intrinsic antiviral factors by myeloid cells is a recently recognized mechanism of restricting lentiviral replication. Viruses that enter these cells must develop strategies to evade cellular antiviral factors to establish a productive infection. By studying the cellular targets of virally encoded proteins that are necessary to infect myeloid cells, a better understanding of cellular intrinsic antiviral strategies has now been achieved. Recent findings have provided insight into how the lentiviral accessory proteins, Vpx, Vpr and Vif counteract antiviral factors found in myeloid cells including SAMHD1, APOBEC3G, APOBEC3A, UNG2 and uracil. Here we review our current understanding of the molecular basis of how cellular antiviral factors function and the viral countermeasures that antagonize them to promote viral transmission and spread.
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Abstract
Reverse transcription and integration are the defining features of the Retroviridae; the common name "retrovirus" derives from the fact that these viruses use a virally encoded enzyme, reverse transcriptase (RT), to convert their RNA genomes into DNA. Reverse transcription is an essential step in retroviral replication. This article presents an overview of reverse transcription, briefly describes the structure and function of RT, provides an introduction to some of the cellular and viral factors that can affect reverse transcription, and discusses fidelity and recombination, two processes in which reverse transcription plays an important role. In keeping with the theme of the collection, the emphasis is on HIV-1 and HIV-1 RT.
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Affiliation(s)
- Wei-Shau Hu
- Viral Recombination Section, HIV Drug Resistance Program, National Cancer Institute, Frederick, Maryland 21702-1201, USA
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50
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Santos S, Obukhov Y, Nekhai S, Bukrinsky M, Iordanskiy S. Virus-producing cells determine the host protein profiles of HIV-1 virion cores. Retrovirology 2012; 9:65. [PMID: 22889230 PMCID: PMC3432596 DOI: 10.1186/1742-4690-9-65] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2012] [Accepted: 07/15/2012] [Indexed: 11/10/2022] Open
Abstract
Background Upon HIV entry into target cells, viral cores are released and rearranged into reverse transcription complexes (RTCs), which support reverse transcription and also protect and transport viral cDNA to the site of integration. RTCs are composed of viral and cellular proteins that originate from both target and producer cells, the latter entering the target cell within the viral core. However, the proteome of HIV-1 viral cores in the context of the type of producer cells has not yet been characterized. Results We examined the proteomic profiles of the cores purified from HIV-1 NL4-3 virions assembled in Sup-T1 cells (T lymphocytes), PMA and vitamin D3 activated THP1 (model of macrophages, mMΦ), and non-activated THP1 cells (model of monocytes, mMN) and assessed potential involvement of identified proteins in the early stages of infection using gene ontology information and data from genome-wide screens on proteins important for HIV-1 replication. We identified 202 cellular proteins incorporated in the viral cores (T cells: 125, mMΦ: 110, mMN: 90) with the overlap between these sets limited to 42 proteins. The groups of RNA binding (29), DNA binding (17), cytoskeleton (15), cytoskeleton regulation (21), chaperone (18), vesicular trafficking-associated (12) and ubiquitin-proteasome pathway-associated proteins (9) were most numerous. Cores of the virions from SupT1 cells contained twice as many RNA binding proteins as cores of THP1-derived virus, whereas cores of virions from mMΦ and mMN were enriched in components of cytoskeleton and vesicular transport machinery, most probably due to differences in virion assembly pathways between these cells. Spectra of chaperones, cytoskeletal proteins and ubiquitin-proteasome pathway components were similar between viral cores from different cell types, whereas DNA-binding and especially RNA-binding proteins were highly diverse. Western blot analysis showed that within the group of overlapping proteins, the level of incorporation of some RNA binding (RHA and HELIC2) and DNA binding proteins (MCM5 and Ku80) in the viral cores from T cells was higher than in the cores from both mMΦ and mMN and did not correlate with the abundance of these proteins in virus producing cells. Conclusions Profiles of host proteins packaged in the cores of HIV-1 virions depend on the type of virus producing cell. The pool of proteins present in the cores of all virions is likely to contain factors important for viral functions. Incorporation ratio of certain RNA- and DNA-binding proteins suggests their more efficient, non-random packaging into virions in T cells than in mMΦ and mMN.
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Affiliation(s)
- Steven Santos
- Department of Microbiology, Immunology and Tropical Medicine, George Washington University School of Medicine and Health Sciences, 2300 I Street NW, Ross Hall, Washington, DC 20037, USA
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