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Moranguinho I, Taveira N, Bártolo I. Antiretroviral Treatment of HIV-2 Infection: Available Drugs, Resistance Pathways, and Promising New Compounds. Int J Mol Sci 2023; 24:ijms24065905. [PMID: 36982978 PMCID: PMC10053740 DOI: 10.3390/ijms24065905] [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: 01/24/2023] [Revised: 03/08/2023] [Accepted: 03/17/2023] [Indexed: 03/30/2023] Open
Abstract
Currently, it is estimated that 1-2 million people worldwide are infected with HIV-2, accounting for 3-5% of the global burden of HIV. The course of HIV-2 infection is longer compared to HIV-1 infection, but without effective antiretroviral therapy (ART), a substantial proportion of infected patients will progress to AIDS and die. Antiretroviral drugs in clinical use were designed for HIV-1 and, unfortunately, some do not work as well, or do not work at all, for HIV-2. This is the case for non-nucleoside reverse transcriptase inhibitors (NNRTIs), the fusion inhibitor enfuvirtide (T-20), most protease inhibitors (PIs), the attachment inhibitor fostemsavir and most broadly neutralizing antibodies. Integrase inhibitors work well against HIV-2 and are included in first-line therapeutic regimens for HIV-2-infected patients. However, rapid emergence of drug resistance and cross-resistance within each drug class dramatically reduces second-line treatment options. New drugs are needed to treat infection with drug-resistant isolates. Here, we review the therapeutic armamentarium available to treat HIV-2-infected patients, as well as promising drugs in development. We also review HIV-2 drug resistance mutations and resistance pathways that develop in HIV-2-infected patients under treatment.
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Affiliation(s)
- Inês Moranguinho
- Instituto de Investigação do Medicamento (iMed.ULisboa), Faculdade de Farmácia, Universidade de Lisboa, 1649-019 Lisboa, Portugal
| | - Nuno Taveira
- Instituto de Investigação do Medicamento (iMed.ULisboa), Faculdade de Farmácia, Universidade de Lisboa, 1649-019 Lisboa, Portugal
- Centro de Investigação Interdisciplinar Egas Moniz (CiiEM), Instituto Superior de Ciências da Saúde Egas Moniz, 2829-511 Caparica, Portugal
| | - Inês Bártolo
- Instituto de Investigação do Medicamento (iMed.ULisboa), Faculdade de Farmácia, Universidade de Lisboa, 1649-019 Lisboa, Portugal
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2
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Gao C, Su X, Wu N, Jin C. A new mechanism of SAMHD1 inhibition of HIV-1 infection by induction of autophagy. Med Hypotheses 2022. [DOI: 10.1016/j.mehy.2022.110890] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Modulation of DNA Damage Response by SAM and HD Domain Containing Deoxynucleoside Triphosphate Triphosphohydrolase (SAMHD1) Determines Prognosis and Treatment Efficacy in Different Solid Tumor Types. Cancers (Basel) 2022; 14:cancers14030641. [PMID: 35158911 PMCID: PMC8833711 DOI: 10.3390/cancers14030641] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Revised: 01/19/2022] [Accepted: 01/21/2022] [Indexed: 12/31/2022] Open
Abstract
SAMHD1 is a deoxynucleotide triphosphate (dNTP) triphosphohydrolase with important roles in the control of cell proliferation and apoptosis, either through the regulation of intracellular dNTPs levels or the modulation of the DNA damage response. However, SAMHD1's role in cancer evolution is still unknown. We performed the first in-depth study of SAMHD1's role in advanced solid tumors, by analyzing samples of 128 patients treated with chemotherapy agents based on platinum derivatives and/or antimetabolites, developing novel in vitro knock-out models to explore the mechanisms driving SAMHD1 function in cancer. Low (or no) expression of SAMHD1 was associated with a positive prognosis in breast, ovarian, and non-small cell lung cancer (NSCLC) cancer patients. A predictive value was associated with low-SAMHD1 expression in NSCLC and ovarian patients treated with antimetabolites in combination with platinum derivatives. In vitro, SAMHD1 knock-out cells showed increased γ-H2AX and apoptosis, suggesting that SAMHD1 depletion induces DNA damage leading to cell death. In vitro treatment with platinum-derived drugs significantly enhanced γ-H2AX and apoptotic markers expression in knock-out cells, indicating a synergic effect of SAMHD1 depletion and platinum-based treatment. SAMHD1 expression represents a new strong prognostic and predictive biomarker in solid tumors and, thus, modulation of the SAMHD1 function may constitute a promising target for the improvement of cancer therapy.
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4
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Dual roles of SAMHD1 in tumor development and chemoresistance to anticancer drugs. Oncol Lett 2021; 21:451. [PMID: 33907561 PMCID: PMC8063254 DOI: 10.3892/ol.2021.12712] [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: 10/14/2020] [Accepted: 03/10/2021] [Indexed: 11/05/2022] Open
Abstract
Human sterile alpha motif and HD-domain-containing protein 1 (SAMHD1) has been identified as a GTP or dGTP-dependent deoxynucleotide triphosphohydrolase (dNTPase) and acts as an antiviral factor against certain retroviruses and DNA viruses. Genetic mutation in SAMHD1 causes the inflammatory Aicardi-Goutières Syndrome and abnormal intracellular deoxyribonucleoside triphosphates (dNTPs) pool. At present, the role of SAMHD1 in numerous types of cancer, such as chronic lymphocytic leukemia, lung cancer and colorectal cancer, is highly studied. Furthermore, it has been found that methylation, acetylation and phosphorylation are involved in the regulation of SAMHD1 expression, and that genetic mutations can cause changes in its activities, including dNTPase activity, long interspersed element type 1 (LINE-1) suppression and DNA damage repair, which could lead to uncontrolled cell cycle progression and cancer development. In addition, SAMHD1 has been reported to have a negative regulatory role in the chemosensitivity to anticancer drugs through its dNTPase activity. The present review aimed to summarize the regulation of SAMHD1 expression in cancer and its function in tumor growth and chemotherapy sensitivity, and discussed controversial points and future directions.
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5
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SAMHD1 … and Viral Ways around It. Viruses 2021; 13:v13030395. [PMID: 33801276 PMCID: PMC7999308 DOI: 10.3390/v13030395] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 02/24/2021] [Accepted: 02/25/2021] [Indexed: 12/19/2022] Open
Abstract
The SAM and HD domain-containing protein 1 (SAMHD1) is a dNTP triphosphohydrolase that plays a crucial role for a variety of different cellular functions. Besides balancing intracellular dNTP concentrations, facilitating DNA damage repair, and dampening excessive immune responses, SAMHD1 has been shown to act as a major restriction factor against various virus species. In addition to its well-described activity against retroviruses such as HIV-1, SAMHD1 has been identified to reduce the infectivity of different DNA viruses such as the herpesviruses CMV and EBV, the poxvirus VACV, or the hepadnavirus HBV. While some viruses are efficiently restricted by SAMHD1, others have developed evasion mechanisms that antagonize the antiviral activity of SAMHD1. Within this review, we summarize the different cellular functions of SAMHD1 and highlight the countermeasures viruses have evolved to neutralize the restriction factor SAMHD1.
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Rothenburger T, McLaughlin KM, Herold T, Schneider C, Oellerich T, Rothweiler F, Feber A, Fenton TR, Wass MN, Keppler OT, Michaelis M, Cinatl J. SAMHD1 is a key regulator of the lineage-specific response of acute lymphoblastic leukaemias to nelarabine. Commun Biol 2020; 3:324. [PMID: 32581304 PMCID: PMC7314829 DOI: 10.1038/s42003-020-1052-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Accepted: 06/02/2020] [Indexed: 12/31/2022] Open
Abstract
The nucleoside analogue nelarabine, the prodrug of arabinosylguanine (AraG), is effective against T-cell acute lymphoblastic leukaemia (T-ALL) but not against B-cell ALL (B-ALL). The underlying mechanisms have remained elusive. Here, data from pharmacogenomics studies and a panel of ALL cell lines reveal an inverse correlation between nelarabine sensitivity and the expression of SAMHD1, which can hydrolyse and inactivate triphosphorylated nucleoside analogues. Lower SAMHD1 abundance is detected in T-ALL than in B-ALL in cell lines and patient-derived leukaemic blasts. Mechanistically, T-ALL cells display increased SAMHD1 promoter methylation without increased global DNA methylation. SAMHD1 depletion sensitises B-ALL cells to AraG, while ectopic SAMHD1 expression in SAMHD1-null T-ALL cells induces AraG resistance. SAMHD1 has a larger impact on nelarabine/AraG than on cytarabine in ALL cells. Opposite effects are observed in acute myeloid leukaemia cells, indicating entity-specific differences. In conclusion, SAMHD1 promoter methylation and, in turn, SAMHD1 expression levels determine ALL cell response to nelarabine.
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Affiliation(s)
- Tamara Rothenburger
- Institut für Medizinische Virologie, Klinikum der Goethe-Universität, Paul Ehrlich-Straße 40, 60596, Frankfurt am Main, Germany
| | | | - Tobias Herold
- Department of Medicine III, University Hospital, LMU Munich, Marchioninistraße 15, 81377, Munich, Germany
- Research Unit Apoptosis in Hematopoietic Stem Cells, Helmholtz Zentrum München, German Research Center for Environmental Health (HMGU), Feodor-Lynenstraße 21, 81377, Munich, Germany
| | - Constanze Schneider
- Institut für Medizinische Virologie, Klinikum der Goethe-Universität, Paul Ehrlich-Straße 40, 60596, Frankfurt am Main, Germany
- Department of Medicine II, Hematology/Oncology, Goethe-Universität, Frankfurt am Main, Germany; Frankfurt Cancer Institute, Goethe University, Theodor-Stern-Kai 7, 60590, Frankfurt am Main, Germany
| | - Thomas Oellerich
- Department of Medicine II, Hematology/Oncology, Goethe-Universität, Theodor-Stern-Kai 7, 60590, Frankfurt am Main, Germany
- Frankfurt Cancer Institute, Goethe University, Theodor-Stern-Kai 7, 60590, Frankfurt am Main, Germany
- German Cancer Consortium/German Cancer Research Center, Im Neuenheimer Feld 280, 69120, Heidelberg, Germany
| | - Florian Rothweiler
- Institut für Medizinische Virologie, Klinikum der Goethe-Universität, Paul Ehrlich-Straße 40, 60596, Frankfurt am Main, Germany
| | - Andrew Feber
- Division of Surgery and Interventional Science, University College London, Gower Street, London, WC1E 6BT, UK
| | - Tim R Fenton
- School of Biosciences, University of Kent, Canterbury, CT2 7NJ, UK
| | - Mark N Wass
- School of Biosciences, University of Kent, Canterbury, CT2 7NJ, UK
| | - Oliver T Keppler
- Faculty of Medicine, Max von Pettenkofer Institute, Virology, LMU München, Pettenkoferstraße 9a, 80336, Munich, Germany
| | - Martin Michaelis
- School of Biosciences, University of Kent, Canterbury, CT2 7NJ, UK.
| | - Jindrich Cinatl
- Institut für Medizinische Virologie, Klinikum der Goethe-Universität, Paul Ehrlich-Straße 40, 60596, Frankfurt am Main, Germany.
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Pharmacological Modulation of SAMHD1 Activity by CDK4/6 Inhibitors Improves Anticancer Therapy. Cancers (Basel) 2020; 12:cancers12030713. [PMID: 32197329 PMCID: PMC7140116 DOI: 10.3390/cancers12030713] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 03/09/2020] [Accepted: 03/16/2020] [Indexed: 01/16/2023] Open
Abstract
Sterile alpha motif and histidine-aspartic acid domain-containing protein 1 (SAMHD1) is a dNTP triphosphohydrolase involved in the regulation of the intracellular dNTP pool, linked to viral restriction, cancer development and autoimmune disorders. SAMHD1 function is regulated by phosphorylation through a mechanism controlled by cyclin-dependent kinases and tightly linked to cell cycle progression. Recently, SAMHD1 has been shown to decrease the efficacy of nucleotide analogs used as chemotherapeutic drugs. Here, we demonstrate that SAMHD1 can enhance or decrease the efficacy of various classes of anticancer drug, including nucleotide analogues, but also anti-folate drugs and CDK inhibitors. Importantly, we show that selective CDK4/6 inhibitors are pharmacological activators of SAMHD1 that act by inhibiting its inactivation by phosphorylation. Combinations of a CDK4/6 inhibitor with nucleoside or folate antimetabolites potently enhanced drug efficacy, resulting in highly synergic drug combinations (CI < 0.04). Mechanistic analyses reveal that cell cycle-controlled modulation of SAMHD1 function is the central process explaining changes in anticancer drug efficacy, therefore providing functional proof of the potential of CDK4/6 inhibitors as a new class of adjuvants to boost chemotherapeutic regimens. The evaluation of SAMHD1 expression in cancer tissues allowed for the identification of cancer types that would benefit from the pharmacological modulation of SAMHD1 function. In conclusion, these results indicate that the modulation of SAMHD1 function may represent a promising strategy for the improvement of current antimetabolite-based treatments.
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Morris ER, Taylor IA. The missing link: allostery and catalysis in the anti-viral protein SAMHD1. Biochem Soc Trans 2019; 47:1013-1027. [PMID: 31296733 PMCID: PMC7045340 DOI: 10.1042/bst20180348] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Revised: 06/04/2019] [Accepted: 06/05/2019] [Indexed: 12/11/2022]
Abstract
Vertebrate protein SAMHD1 (sterile-α-motif and HD domain containing protein 1) regulates the cellular dNTP (2'-deoxynucleoside-5'-triphosphate) pool by catalysing the hydrolysis of dNTP into 2'-deoxynucleoside and triphosphate products. As an important regulator of cell proliferation and a key player in dNTP homeostasis, mutations to SAMHD1 are implicated in hypermutated cancers, and germline mutations are associated with Chronic Lymphocytic Leukaemia and the inflammatory disorder Aicardi-Goutières Syndrome. By limiting the supply of dNTPs for viral DNA synthesis, SAMHD1 also restricts the replication of several retroviruses, such as HIV-1, and some DNA viruses in dendritic and myeloid lineage cells and resting T-cells. SAMHD1 activity is regulated throughout the cell cycle, both at the level of protein expression and post-translationally, through phosphorylation. In addition, allosteric regulation further fine-tunes the catalytic activity of SAMHD1, with a nucleotide-activated homotetramer as the catalytically active form of the protein. In cells, GTP and dATP are the likely physiological activators of two adjacent allosteric sites, AL1 (GTP) and AL2 (dATP), that bridge monomer-monomer interfaces to stabilise the protein homotetramer. This review summarises the extensive X-ray crystallographic, biophysical and molecular dynamics experiments that have elucidated important features of allosteric regulation in SAMHD1. We present a comprehensive mechanism detailing the structural and protein dynamics components of the allosteric coupling between nucleotide-induced tetramerization and the catalysis of dNTP hydrolysis by SAMHD1.
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Affiliation(s)
- Elizabeth R Morris
- Macromolecular Structure Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, U.K.
| | - Ian A Taylor
- Macromolecular Structure Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, U.K
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Garcia-Vidal E, Badia R, Pujantell M, Castellví M, Felip E, Clotet B, Riveira-Muñoz E, Ballana E, Esté JA. Dual effect of the broad spectrum kinase inhibitor midostaurin in acute and latent HIV-1 infection. Antiviral Res 2019; 168:18-27. [PMID: 31077767 DOI: 10.1016/j.antiviral.2019.05.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 04/03/2019] [Accepted: 05/07/2019] [Indexed: 01/26/2023]
Abstract
Midostaurin is a multi-kinase inhibitor with antineoplastic activity. We assessed the capacity of midostaurin to affect early and late steps of HIV-1 infection and to reactivate HIV-1 latently infected cells, alone or in combination with histone deacetylase inhibitors (HDACi) known to act as latency-reversing agents (LRA). Acute HIV-1 infection was assessed by flow cytometry in three cell types treated with midostaurin in the presence or absence of SAMHD1. Non-infected cells were treated with midostaurin and harvested for Western blot analysis. Macrophage infections were also measured by quantitative RT-PCR. HIV-1 latency reactivation was assessed in several latency models. Midostaurin induced G2/M arrest and inhibited CDK2, preventing the phosphorylation of SAMHD1 associated to inhibition of its dNTPase activity. In the presence of SAMHD1, midostaurin blocked HIV-1 DNA formation and viral replication. However, following Vpx-mediated SAMHD1 degradation, midostaurin increased viral transcripts and virus replication. In three out of four HIV-1 latency models, including primary CD4+ T cells, midostaurin effectively reversed HIV-1 latency and was synergistic in combination with LRA vorinostat and panobinostat. Our study describes a dual effect for midostaurin in HIV-1 infection, antiviral or proviral depending on SAMHD1 activation, and highlights a role for active SAMHD1 in regulating the activity of potential HIV-1 latency reversal agents.
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Affiliation(s)
- Edurne Garcia-Vidal
- AIDS Research Institute - IrsiCaixa, AIDS Unit and Health Research Institute Germans Trias i Pujol (IGTP), Hospital Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain
| | - Roger Badia
- AIDS Research Institute - IrsiCaixa, AIDS Unit and Health Research Institute Germans Trias i Pujol (IGTP), Hospital Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain
| | - Maria Pujantell
- AIDS Research Institute - IrsiCaixa, AIDS Unit and Health Research Institute Germans Trias i Pujol (IGTP), Hospital Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain
| | - Marc Castellví
- AIDS Research Institute - IrsiCaixa, AIDS Unit and Health Research Institute Germans Trias i Pujol (IGTP), Hospital Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain
| | - Eudald Felip
- AIDS Research Institute - IrsiCaixa, AIDS Unit and Health Research Institute Germans Trias i Pujol (IGTP), Hospital Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain
| | - Bonaventura Clotet
- AIDS Research Institute - IrsiCaixa, AIDS Unit and Health Research Institute Germans Trias i Pujol (IGTP), Hospital Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain
| | - Eva Riveira-Muñoz
- AIDS Research Institute - IrsiCaixa, AIDS Unit and Health Research Institute Germans Trias i Pujol (IGTP), Hospital Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain
| | - Ester Ballana
- AIDS Research Institute - IrsiCaixa, AIDS Unit and Health Research Institute Germans Trias i Pujol (IGTP), Hospital Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain.
| | - José A Esté
- AIDS Research Institute - IrsiCaixa, AIDS Unit and Health Research Institute Germans Trias i Pujol (IGTP), Hospital Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain.
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Increased SAMHD1 transcript expression correlates with interferon-related genes in HIV-1-infected patients. Med Microbiol Immunol 2018; 208:679-691. [PMID: 30564919 DOI: 10.1007/s00430-018-0574-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Accepted: 11/24/2018] [Indexed: 01/12/2023]
Abstract
PURPOSE To investigate the contribution of SAMHD1 to HIV-1 infection in vivo and its relationship with IFN response, the expression of SAMHD1 and IFN-related pathways was evaluated in HIV-1-infected patients. METHODS Peripheral blood mononuclear cells (PBMC) from 388 HIV-1-infected patients, both therapy naïve (n = 92) and long-term HAART treated (n = 296), and from 100 gender and age-matched healthy individuals were examined. CD4+ T cells, CD14+ monocytes and gut biopsies were also analyzed in HIV-1-infected subjects on suppressive antiretroviral therapy. Gene expression levels of SAMDH1, ISGs (MxA, MxB, HERC5, IRF7) and IRF3 were evaluated by real-time RT-PCR assays. RESULTS SAMHD1 levels in HIV-1-positive patients were significantly increased compared to those in healthy donors. SAMHD1 expression was enhanced in treated patients compared to naïve patients (p < 0.0001) and healthy donors (p = 0.0038). Virologically suppressed treated patients exhibited higher SAMHD1 levels than healthy donors (p = 0.0008), viraemic patients (p = 0.0001) and naïve patients (p < 0.0001). SAMHD1 levels were also increased in CD4+ T cells compared to those in CD14+ monocytes and in PBMC compared to those of GALT. Moreover, SAMHD1 was expressed more strongly than ISGs in HIV-1-infected patients and positive correlations were found between SAMHD1, ISGs and IRF3 levels. CONCLUSIONS SAMHD1 is more strongly expressed than the classical IFN-related genes, increased during antiretroviral therapy and correlated with ISGs and IRF3 in HIV-1-infected patients.
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Mauney CH, Perrino FW, Hollis T. Identification of Inhibitors of the dNTP Triphosphohydrolase SAMHD1 Using a Novel and Direct High-Throughput Assay. Biochemistry 2018; 57:6624-6636. [PMID: 30380297 DOI: 10.1021/acs.biochem.8b01038] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The dNTP triphosphohydrolase SAMHD1 is a regulator of cellular dNTP pools. Given its central role in nucleotide metabolism, SAMHD1 performs important functions in cellular homeostasis, cell cycle regulation, and innate immunity. It therefore represents a high-profile target for small molecule drug design. SAMHD1 has a complex mechanism of catalytic activation that makes the design of an activating compound challenging. However, an inhibitor of SAMHD1 could serve multiple therapeutic roles, including the potentiation of antiviral and anticancer drug regimens. The lack of high-throughput screens that directly measure SAMHD1 catalytic activity has impeded efforts to identify inhibitors of SAMHD1. Here we describe a novel high-throughput screen that directly measures SAMHD1 catalytic activity. This assay results in a colorimetric end point that can be read spectrophotometrically and utilizes bis(4-nitrophenyl) phosphate as the substrate and Mn2+ as the activating cation that facilitates catalysis. When used to screen a library of Food and Drug Administration-approved drugs, this HTS identified multiple novel compounds that inhibited SAMHD1 dNTPase activity at micromolar concentrations.
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Affiliation(s)
- Christopher H Mauney
- Center for Structural Biology, Department of Biochemistry , Wake Forest School of Medicine , Winston-Salem , North Carolina 27157 , United States
| | - Fred W Perrino
- Center for Structural Biology, Department of Biochemistry , Wake Forest School of Medicine , Winston-Salem , North Carolina 27157 , United States
| | - Thomas Hollis
- Center for Structural Biology, Department of Biochemistry , Wake Forest School of Medicine , Winston-Salem , North Carolina 27157 , United States
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Moketla MB, Wadley AL, Kamerman P, de Assis Rosa D. Pharmacogenetic variation influences sensory neuropathy occurrence in Southern Africans treated with stavudine-containing antiretroviral therapy. PLoS One 2018; 13:e0204111. [PMID: 30273369 PMCID: PMC6166924 DOI: 10.1371/journal.pone.0204111] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Accepted: 09/03/2018] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND The use of the HIV antiretroviral drug stavudine (d4T), a thymidine analogue, is associated with the development of mitochondrial toxicities such as sensory neuropathy (SN). Genetic variation in genes relating to d4T transport and metabolism, as well as genetic variation in the thymidine synthesis pathway, could influence occurrence of d4T-related toxicity. METHODS We examined this hypothesis in a cohort of HIV-positive South African adults exposed to d4T, including 143 cases with SN and 120 controls without SN. Ten SNPs in four genes associated with stavudine transport, and 16 SNPs in seven genes of the thymidine synthesis / phosphorylation pathway were genotyped using Agena mass spectrometry methods. Associations between sensory neuropathy and genetic variants were evaluated using PLINK by univariate and multivariable analyses. RESULTS Age and height were significantly associated with SN occurrence. Using logistic regression with age and height as covariates, and uncorrected empirical p-values, genetic variation in SLC28A1, SAMHD1, MTHFR and RRM2B was associated with SN in South Africans using d4T. CONCLUSION Variation in genes relating to d4T transport and metabolism, as well as genetic variation in the thymidine synthesis pathway may influence occurrence of d4T-related SN. These data contribute to the characterisation of African pharmacogenetic variation and its role in adverse response to antiretroviral therapy.
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Affiliation(s)
- Marvin Blessings Moketla
- School of Molecular and Cell Biology, Faculty of Science, University of the Witwatersrand, Johannesburg, South Africa
| | - Antonia L. Wadley
- Brain Function Research Group, School of Physiology, Faculty of Health Science, University of the Witwatersrand, Johannesburg, South Africa
| | - Peter Kamerman
- Brain Function Research Group, School of Physiology, Faculty of Health Science, University of the Witwatersrand, Johannesburg, South Africa
- School of Pharmacy and Biomedical Sciences, Faculty of Health Sciences, Curtin University, Perth, Australia
| | - Debra de Assis Rosa
- School of Molecular and Cell Biology, Faculty of Science, University of the Witwatersrand, Johannesburg, South Africa
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CD32 expression is associated to T-cell activation and is not a marker of the HIV-1 reservoir. Nat Commun 2018; 9:2739. [PMID: 30013105 PMCID: PMC6048139 DOI: 10.1038/s41467-018-05157-w] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Accepted: 06/12/2018] [Indexed: 11/26/2022] Open
Abstract
CD32 has been shown to be preferentially expressed in latently HIV-1-infected cells in an in vitro model of quiescent CD4 T cells. Here we show that stimulation of CD4+ T cells with IL-2, IL-7, PHA, and anti-CD3/CD28 antibodies induces T-cell proliferation, co-expression of CD32 and the activation of the markers HLA-DR and CD69. HIV-1 infection increases CD32 expression. 79.2% of the CD32+/CD4+ T cells from HIV+ individuals under antiretroviral treatment were HLA-DR+. Resting CD4+ T cells infected in vitro generally results in higher integration of provirus. We observe no difference in provirus integration or replication-competent inducible latent HIV-1 in CD32+ or CD32− CD4+ T cells from HIV+ individuals. Our results demonstrate that CD32 expression is a marker of CD4+ T cell activation in HIV+ individuals and raises questions regarding the immune resting status of CD32+ cells harboring HIV-1 proviruses. CD32 has been previously shown to be expressed preferentially by CD4 T cells latently harbouring HIV-1. Here the authors show that CD32 expression in CD4 T cells is associated with T cell activation, is up-regulated by HIV-1 infection and importantly does not appear to represent an enriched cellular niche for latent HIV-1.
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Mauney CH, Hollis T. SAMHD1: Recurring roles in cell cycle, viral restriction, cancer, and innate immunity. Autoimmunity 2018; 51:96-110. [PMID: 29583030 PMCID: PMC6117824 DOI: 10.1080/08916934.2018.1454912] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Accepted: 03/16/2018] [Indexed: 12/24/2022]
Abstract
Sterile alpha motif and histidine-aspartic acid domain-containing protein 1 (SAMHD1) is a deoxynucleotide triphosphate (dNTP) hydrolase that plays an important role in the homeostatic balance of cellular dNTPs. Its emerging role as an effector of innate immunity is affirmed by mutations in the SAMHD1 gene that cause the severe autoimmune disease, Aicardi-Goutieres syndrome (AGS) and that are linked to cancer. Additionally, SAMHD1 functions as a restriction factor for retroviruses, such as HIV. Here, we review the current biochemical and biological properties of the enzyme including its structure, activity, and regulation by post-translational modifications in the context of its cellular function. We outline open questions regarding the biology of SAMHD1 whose answers will be important for understanding its function as a regulator of cell cycle progression, genomic integrity, and in autoimmunity.
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Affiliation(s)
- Christopher H Mauney
- a Department of Biochemistry , Center for Structural Biology, Wake Forest School of Medicine , Winston Salem , NC , USA
| | - Thomas Hollis
- a Department of Biochemistry , Center for Structural Biology, Wake Forest School of Medicine , Winston Salem , NC , USA
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15
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Johansson P, Klein-Hitpass L, Choidas A, Habenberger P, Mahboubi B, Kim B, Bergmann A, Scholtysik R, Brauser M, Lollies A, Siebert R, Zenz T, Dührsen U, Küppers R, Dürig J. SAMHD1 is recurrently mutated in T-cell prolymphocytic leukemia. Blood Cancer J 2018; 8:11. [PMID: 29352181 PMCID: PMC5802577 DOI: 10.1038/s41408-017-0036-5] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Revised: 10/05/2017] [Accepted: 10/12/2017] [Indexed: 01/19/2023] Open
Abstract
T-cell prolymphocytic leukemia (T-PLL) is an aggressive malignancy with a median survival of the patients of less than two years. Besides characteristic chromosomal translocations, frequent mutations affect the ATM gene, JAK/STAT pathway members, and epigenetic regulators. We here performed a targeted mutation analysis for 40 genes selected from a RNA sequencing of 10 T-PLL in a collection of 28 T-PLL, and an exome analysis of five further cases. Nonsynonymous mutations were identified in 30 of the 40 genes, 18 being recurrently mutated. We identified recurrently mutated genes previously unknown to be mutated in T-PLL, which are SAMHD1, HERC1, HERC2, PRDM2, PARP10, PTPRC, and FOXP1. SAMHD1 regulates cellular deoxynucleotide levels and acts as a potential tumor suppressor in other leukemias. We observed destructive mutations in 18% of cases as well as deletions in two further cases. Taken together, we identified additional genes involved in JAK/STAT signaling (PTPRC), epigenetic regulation (PRDM2), or DNA damage repair (SAMHD1, PARP10, HERC1, and HERC2) as being recurrently mutated in T-PLL. Thus, our study considerably extends the picture of pathways involved in molecular pathogenesis of T-PLL and identifies the tumor suppressor gene SAMHD1 with ~20% of T-PLL affected by destructive lesions likely as major player in T-PLL pathogenesis.
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Affiliation(s)
- Patricia Johansson
- Department of Hematology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany. .,Institute of Cell Biology (Cancer Research), University Hospital Essen, University of Duisburg-Essen, Essen, Germany.
| | - Ludger Klein-Hitpass
- Institute of Cell Biology (Cancer Research), University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | | | | | - Bijan Mahboubi
- Center for Drug Discovery, Department of Pediatrics, Emory Center for AIDS Research, Emory University, Children's Healthcare of Atlanta, Atlanta, GA, USA
| | - Baek Kim
- Center for Drug Discovery, Department of Pediatrics, Emory Center for AIDS Research, Emory University, Children's Healthcare of Atlanta, Atlanta, GA, USA
| | - Anke Bergmann
- Institute for Human Genetics, Christian-Albrechts-University Kiel and University Hospital Schleswig Holstein, Kiel, Germany
| | - René Scholtysik
- Institute of Cell Biology (Cancer Research), University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Martina Brauser
- Institute of Cell Biology (Cancer Research), University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Anna Lollies
- Institute of Cell Biology (Cancer Research), University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Reiner Siebert
- Institute for Human Genetics, Christian-Albrechts-University Kiel and University Hospital Schleswig Holstein, Kiel, Germany.,Institute of Human Genetics, University of Ulm and University Hospital of Ulm, Ulm, Germany
| | - Thorsten Zenz
- Department of Molecular Therapy in Haematology and Oncology, National Center for Tumor Diseases and German Cancer Research Center, Department of Medicine V, University Hospital Heidelberg, Heidelberg, Germany.,German Cancer Consortium (DKTK), Heidelberg, Germany
| | - Ulrich Dührsen
- Department of Hematology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Ralf Küppers
- Institute of Cell Biology (Cancer Research), University Hospital Essen, University of Duisburg-Essen, Essen, Germany.,German Cancer Consortium (DKTK), Heidelberg, Germany
| | - Jan Dürig
- Department of Hematology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany.,German Cancer Consortium (DKTK), Heidelberg, Germany
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16
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Antonucci JM, St Gelais C, Wu L. The Dynamic Interplay between HIV-1, SAMHD1, and the Innate Antiviral Response. Front Immunol 2017; 8:1541. [PMID: 29176984 PMCID: PMC5686096 DOI: 10.3389/fimmu.2017.01541] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2017] [Accepted: 10/30/2017] [Indexed: 01/03/2023] Open
Abstract
The innate immune response constitutes the first cellular line of defense against initial HIV-1 infection. Immune cells sense invading virus and trigger signaling cascades that induce antiviral defenses to control or eliminate infection. Professional antigen-presenting cells located in mucosal tissues, including dendritic cells and macrophages, are critical for recognizing HIV-1 at the site of initial exposure. These cells are less permissive to HIV-1 infection compared to activated CD4+ T-cells, which is mainly due to host restriction factors that serve an immediate role in controlling the establishment or spread of viral infection. However, HIV-1 can exploit innate immune cells and their cellular factors to avoid detection and clearance by the host immune system. Sterile alpha motif and HD-domain containing protein 1 (SAMHD1) is the mammalian deoxynucleoside triphosphate triphosphohydrolase responsible for regulating intracellular dNTP pools and restricting the replication of HIV-1 in non-dividing myeloid cells and quiescent CD4+ T-cells. Here, we review and analyze the latest literature on the antiviral function of SAMHD1, including the mechanism of HIV-1 restriction and the ability of SAMHD1 to regulate the innate immune response to viral infection. We also provide an overview of the dynamic interplay between HIV-1, SAMHD1, and the cell-intrinsic antiviral response to elucidate how SAMHD1 modulates HIV-1 infection in non-dividing immune cells. A more complete understanding of SAMHD1’s role in the innate immune response to HIV-1 infection may help develop stratagems to enhance its antiviral effects and to more efficiently block HIV-1 replication and avoid the pathogenic result of viral infection.
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Affiliation(s)
- Jenna M Antonucci
- Center for Retrovirus Research, Department of Veterinary Biosciences, The Ohio State University, Columbus, OH, United States
| | - Corine St Gelais
- Center for Retrovirus Research, Department of Veterinary Biosciences, The Ohio State University, Columbus, OH, United States
| | - Li Wu
- Center for Retrovirus Research, Department of Veterinary Biosciences, The Ohio State University, Columbus, OH, United States
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17
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Badia R, Pujantell M, Torres-Torronteras J, Menéndez-Arias L, Martí R, Ruzo A, Pauls E, Clotet B, Ballana E, Esté JA, Riveira-Muñoz E. SAMHD1 is active in cycling cells permissive to HIV-1 infection. Antiviral Res 2017; 142:123-135. [PMID: 28359840 DOI: 10.1016/j.antiviral.2017.03.019] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Revised: 02/24/2017] [Accepted: 03/25/2017] [Indexed: 12/19/2022]
Abstract
SAMHD1 is a triphosphohydrolase that restricts HIV-1 by limiting the intracellular dNTP pool required for reverse transcription. Although SAMHD1 is expressed and active/unphosphorylated in most cell lines, its restriction activity is thought to be relevant only in non-cycling cells. However, an in depth evaluation of SAMHD1 function and relevance in cycling cells is required. Here, we show that SAMHD1-induced degradation by HIV-2 Vpx affects the dNTP pool and HIV-1 replication capacity in the presence of the 3'-azido-3'-deoxythymidine (AZT) in cycling cells. Similarly, in SAMHD1 knockout cells, HIV-1 showed increased replicative capacity in the presence of nucleoside inhibitors, especially AZT, that was reverted by re-expression of wild type SAMHD1. Sensitivity to non-nucleoside inhibitors (nevirapine and efavirenz) or the integrase inhibitor raltegravir was not affected by SAMHD1. Combination of three mutations (S18A, T21A, T25A) significantly prevented SAMHD1 phosphorylation but did not significantly affect HIV-1 replication in the presence of AZT. Our results demonstrate that SAMHD1 is active in HIV-1 permissive cells, does not modify susceptibility to HIV-1 infection but strongly affects sensitivity to nucleoside inhibitors.
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Affiliation(s)
- Roger Badia
- AIDS Research Institute - IrsiCaixa and Health Research, Institute Germans Trias i Pujol (IGTP), Hospital Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain
| | - Maria Pujantell
- AIDS Research Institute - IrsiCaixa and Health Research, Institute Germans Trias i Pujol (IGTP), Hospital Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain
| | - Javier Torres-Torronteras
- Research Group on Neuromuscular and Mitochondrial Disorders, Vall d'Hebron Institut de Recerca, Universitat Autònoma de Barcelona, Biomedical Network Research Centre on Rare Diseases (CIBERER), Instituto de Salud Carlos III, Spain
| | - Luis Menéndez-Arias
- Centro de Biología Molecular "Severo Ochoa", Consejo Superior de Investigaciones Científicas, Universidad Autónoma de Madrid, Madrid, Spain
| | - Ramón Martí
- Research Group on Neuromuscular and Mitochondrial Disorders, Vall d'Hebron Institut de Recerca, Universitat Autònoma de Barcelona, Biomedical Network Research Centre on Rare Diseases (CIBERER), Instituto de Salud Carlos III, Spain
| | - Albert Ruzo
- Laboratory of Molecular Embryology, The Rockefeller University, New York, NY, USA
| | - Eduardo Pauls
- AIDS Research Institute - IrsiCaixa and Health Research, Institute Germans Trias i Pujol (IGTP), Hospital Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain; Joint IRB-BSC-CRG Program in Computational Biology, Institute for Research in Biomedicine, The Barcelona Institute of Science and Technology, Barcelona, Catalonia, Spain
| | - Bonaventura Clotet
- AIDS Research Institute - IrsiCaixa and Health Research, Institute Germans Trias i Pujol (IGTP), Hospital Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain
| | - Ester Ballana
- AIDS Research Institute - IrsiCaixa and Health Research, Institute Germans Trias i Pujol (IGTP), Hospital Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain
| | - José A Esté
- AIDS Research Institute - IrsiCaixa and Health Research, Institute Germans Trias i Pujol (IGTP), Hospital Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain.
| | - Eva Riveira-Muñoz
- AIDS Research Institute - IrsiCaixa and Health Research, Institute Germans Trias i Pujol (IGTP), Hospital Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain.
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18
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Álvarez M, Sebastián-Martín A, García-Marquina G, Menéndez-Arias L. Fidelity of classwide-resistant HIV-2 reverse transcriptase and differential contribution of K65R to the accuracy of HIV-1 and HIV-2 reverse transcriptases. Sci Rep 2017; 7:44834. [PMID: 28333133 PMCID: PMC5363063 DOI: 10.1038/srep44834] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Accepted: 02/13/2017] [Indexed: 11/23/2022] Open
Abstract
Nucleoside reverse transcriptase (RT) inhibitors constitute the backbone of current therapies against human immunodeficiency virus type 1 and type 2 (HIV-1 and HIV-2, respectively). However, mutational pathways leading to the development of nucleoside analogue resistance are different in both types of HIV. In HIV-2, resistance to all approved nucleoside analogues is conferred by the combination of RT substitutions K65R, Q151M and M184V. Nucleotide incorporation kinetic analyses of mutant and wild-type (WT) HIV-2 RTs show that the triple-mutant has decreased catalytic efficiency due to the presence of M184V. Although similar effects were previously reported for equivalent mutations in HIV-1 RT, the HIV-2 enzymes were catalytically less efficient. Interestingly, in highly divergent HIV-1 RTs, K65R confers several-fold increased accuracy of DNA synthesis. We have determined the intrinsic fidelity of DNA synthesis of WT HIV-2 RT and mutants K65R and K65R/Q151M/M184V. Our results show that those changes in HIV-2 RT have a relatively small impact on nucleotide selectivity. Furthermore, we found that there were less than two-fold differences in error rates obtained with forward mutation assays using mutant and WT HIV-2 RTs. A different conformation of the β3-β4 hairpin loop in HIV-1 and HIV-2 RTs could probably explain the differential effects of K65R.
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Affiliation(s)
- Mar Álvarez
- Centro de Biología Molecular "Severo Ochoa" (Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid), Madrid, Spain
| | - Alba Sebastián-Martín
- Centro de Biología Molecular "Severo Ochoa" (Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid), Madrid, Spain
| | - Guillermo García-Marquina
- Centro de Biología Molecular "Severo Ochoa" (Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid), Madrid, Spain
| | - Luis Menéndez-Arias
- Centro de Biología Molecular "Severo Ochoa" (Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid), Madrid, Spain
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19
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Ordonez P, Kunzelmann S, Groom HCT, Yap MW, Weising S, Meier C, Bishop KN, Taylor IA, Stoye JP. SAMHD1 enhances nucleoside-analogue efficacy against HIV-1 in myeloid cells. Sci Rep 2017; 7:42824. [PMID: 28220857 PMCID: PMC5318888 DOI: 10.1038/srep42824] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Accepted: 01/16/2017] [Indexed: 11/17/2022] Open
Abstract
SAMHD1 is an intracellular enzyme that specifically degrades deoxynucleoside triphosphates into component nucleoside and inorganic triphosphate. In myeloid-derived dendritic cells and macrophages as well as resting T-cells, SAMHD1 blocks HIV-1 infection through this dNTP triphosphohydrolase activity by reducing the cellular dNTP pool to a level that cannot support productive reverse transcription. We now show that, in addition to this direct effect on virus replication, manipulating cellular SAMHD1 activity can significantly enhance or decrease the anti-HIV-1 efficacy of nucleotide analogue reverse transcription inhibitors presumably as a result of modulating dNTP pools that compete for recruitment by viral polymerases. Further, a variety of other nucleotide-based analogues, not normally considered antiretrovirals, such as the anti-herpes drugs Aciclovir and Ganciclovir and the anti-cancer drug Clofarabine are now revealed as potent anti-HIV-1 agents, under conditions of low dNTPs. This in turn suggests novel uses for nucleotide analogues to inhibit HIV-1 in differentiated cells low in dNTPs.
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Affiliation(s)
- Paula Ordonez
- Retrovirus-Host Interactions Laboratory, The Francis Crick Institute, London, UK
| | - Simone Kunzelmann
- Structural Biology Science Technology Platform, The Francis Crick Institute, London, UK
| | - Harriet C. T. Groom
- Infection and Replication of Retroviruses Laboratory, The Francis Crick Institute, London, UK
| | - Melvyn W. Yap
- Retrovirus-Host Interactions Laboratory, The Francis Crick Institute, London, UK
| | - Simon Weising
- Organic Chemistry, Department of Chemistry, Faculty of Sciences, University of Hamburg, Germany
| | - Chris Meier
- Organic Chemistry, Department of Chemistry, Faculty of Sciences, University of Hamburg, Germany
| | - Kate N. Bishop
- Infection and Replication of Retroviruses Laboratory, The Francis Crick Institute, London, UK
| | - Ian A. Taylor
- Macromolecular Structure Laboratory, The Francis Crick Institute, London, UK
| | - Jonathan P. Stoye
- Retrovirus-Host Interactions Laboratory, The Francis Crick Institute, London, UK
- Faculty of Medicine, Imperial College London, London, UK
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20
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Hollenbaugh JA, Shelton J, Tao S, Amiralaei S, Liu P, Lu X, Goetze RW, Zhou L, Nettles JH, Schinazi RF, Kim B. Substrates and Inhibitors of SAMHD1. PLoS One 2017; 12:e0169052. [PMID: 28046007 PMCID: PMC5207538 DOI: 10.1371/journal.pone.0169052] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Accepted: 12/09/2016] [Indexed: 11/19/2022] Open
Abstract
SAMHD1 hydrolyzes 2'-deoxynucleoside-5'-triphosphates (dNTPs) into 2'-deoxynucleosides and inorganic triphosphate products. In this paper, we evaluated the impact of 2' sugar moiety substitution for different nucleotides on being substrates for SAMHD1 and mechanisms of actions for the results. We found that dNTPs ((2'R)-2'-H) are only permissive in the catalytic site of SAMHD1 due to L150 exclusion of (2'R)-2'-F and (2'R)-2'-OH nucleotides. However, arabinose ((2'S)-2'-OH) nucleoside-5'-triphosphates analogs are permissive to bind in the catalytic site and be hydrolyzed by SAMHD1. Moreover, when the (2'S)-2' sugar moiety is increased to a (2'S)-2'-methyl as with the SMDU-TP analog, we detect inhibition of SAMHD1’s dNTPase activity. Our computational modeling suggests that (2'S)-2'-methyl sugar moiety clashing with the Y374 of SAMHD1. We speculate that SMDU-TP mechanism of action requires that the analog first docks in the catalytic pocket of SAMHD1 but prevents the A351-V378 helix conformational change from being completed, which is needed before hydrolysis can occur. Collectively we have identified stereoselective 2' substitutions that reveal nucleotide substrate specificity for SAMHD1, and a novel inhibitory mechanism for the dNTPase activity of SAMHD1. Importantly, our data is beneficial for understanding if FDA-approved antiviral and anticancer nucleosides are hydrolyzed by SAMHD1 in vivo.
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Affiliation(s)
- Joseph A. Hollenbaugh
- Center for AIDS Research, Laboratory of Biochemical Pharmacology, Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia United States of America
| | - Jadd Shelton
- Center for AIDS Research, Laboratory of Biochemical Pharmacology, Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia United States of America
| | - Sijia Tao
- Center for AIDS Research, Laboratory of Biochemical Pharmacology, Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia United States of America
| | - Sheida Amiralaei
- Center for AIDS Research, Laboratory of Biochemical Pharmacology, Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia United States of America
| | - Peng Liu
- Center for AIDS Research, Laboratory of Biochemical Pharmacology, Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia United States of America
| | - Xiao Lu
- Center for AIDS Research, Laboratory of Biochemical Pharmacology, Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia United States of America
| | - Russell W. Goetze
- Center for AIDS Research, Laboratory of Biochemical Pharmacology, Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia United States of America
| | - Longhu Zhou
- Center for AIDS Research, Laboratory of Biochemical Pharmacology, Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia United States of America
| | - James H. Nettles
- Department of Biomedical Informatics and Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia United States of America
| | - Raymond F. Schinazi
- Center for AIDS Research, Laboratory of Biochemical Pharmacology, Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia United States of America
| | - Baek Kim
- Center for AIDS Research, Laboratory of Biochemical Pharmacology, Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia United States of America
- Children’s Healthcare of Atlanta, Atlanta, Georgia United States of America
- College of Pharmacy, Kyung-Hee University, Seoul, South Korea
- * E-mail:
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21
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Schneider C, Oellerich T, Baldauf HM, Schwarz SM, Thomas D, Flick R, Bohnenberger H, Kaderali L, Stegmann L, Cremer A, Martin M, Lohmeyer J, Michaelis M, Hornung V, Schliemann C, Berdel WE, Hartmann W, Wardelmann E, Comoglio F, Hansmann ML, Yakunin AF, Geisslinger G, Ströbel P, Ferreirós N, Serve H, Keppler OT, Cinatl J. SAMHD1 is a biomarker for cytarabine response and a therapeutic target in acute myeloid leukemia. Nat Med 2016; 23:250-255. [PMID: 27991919 DOI: 10.1038/nm.4255] [Citation(s) in RCA: 105] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Accepted: 11/15/2016] [Indexed: 11/09/2022]
Abstract
The nucleoside analog cytarabine (Ara-C) is an essential component of primary and salvage chemotherapy regimens for acute myeloid leukemia (AML). After cellular uptake, Ara-C is converted into its therapeutically active triphosphate metabolite, Ara-CTP, which exerts antileukemic effects, primarily by inhibiting DNA synthesis in proliferating cells. Currently, a substantial fraction of patients with AML fail to respond effectively to Ara-C therapy, and reliable biomarkers for predicting the therapeutic response to Ara-C are lacking. SAMHD1 is a deoxynucleoside triphosphate (dNTP) triphosphohydrolase that cleaves physiological dNTPs into deoxyribonucleosides and inorganic triphosphate. Although it has been postulated that SAMHD1 sensitizes cancer cells to nucleoside-analog derivatives through the depletion of competing dNTPs, we show here that SAMHD1 reduces Ara-C cytotoxicity in AML cells. Mechanistically, dGTP-activated SAMHD1 hydrolyzes Ara-CTP, which results in a drastic reduction of Ara-CTP in leukemic cells. Loss of SAMHD1 activity-through genetic depletion, mutational inactivation of its triphosphohydrolase activity or proteasomal degradation using specialized, virus-like particles-potentiates the cytotoxicity of Ara-C in AML cells. In mouse models of retroviral AML transplantation, as well as in retrospective analyses of adult patients with AML, the response to Ara-C-containing therapy was inversely correlated with SAMHD1 expression. These results identify SAMHD1 as a potential biomarker for the stratification of patients with AML who might best respond to Ara-C-based therapy and as a target for treating Ara-C-refractory AML.
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Affiliation(s)
| | - Thomas Oellerich
- Department of Medicine II, Hematology and Oncology, Goethe University of Frankfurt, Frankfurt, Germany.,Cambridge University Department of Haematology, Cambridge Institute of Medical Research, Cambridge, UK.,German Cancer Consortium partner site, German Cancer Research Center, Heidelberg, Germany
| | - Hanna-Mari Baldauf
- Institute of Medical Virology, University of Frankfurt, Frankfurt, Germany.,Max von Pettenkofer Institute, Department of Virology, Ludwig Maximilian University of Munich, Munich, Germany
| | | | - Dominique Thomas
- Pharmazentrum frankfurt/ZAFES, Institute of Clinical Pharmacology, Goethe University of Frankfurt, Frankfurt, Germany
| | - Robert Flick
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Canada
| | | | - Lars Kaderali
- Institute of Bioinformatics, University Medicine Greifswald, Greifswald, Germany
| | - Lena Stegmann
- Institute of Medical Virology, University of Frankfurt, Frankfurt, Germany
| | - Anjali Cremer
- Department of Medicine II, Hematology and Oncology, Goethe University of Frankfurt, Frankfurt, Germany
| | - Margarethe Martin
- Institute of Medical Virology, University of Frankfurt, Frankfurt, Germany
| | - Julian Lohmeyer
- Department of Medicine II, Hematology and Oncology, Goethe University of Frankfurt, Frankfurt, Germany
| | - Martin Michaelis
- Centre for Molecular Processing and School of Biosciences, University of Kent, Canterbury, UK
| | - Veit Hornung
- Institute of Molecular Medicine, University Hospital Bonn, Bonn, Germany.,Gene Center and Department of Biochemistry, Ludwig Maximilian University of Munich, Munich, Germany
| | - Christoph Schliemann
- Department of Medicine A (Hematology, Oncology), University Hospital Münster, Germany
| | - Wolfgang E Berdel
- Department of Medicine A (Hematology, Oncology), University Hospital Münster, Germany
| | - Wolfgang Hartmann
- Gerhard Domagk Institute for Pathology, University Hospital Münster, Germany
| | - Eva Wardelmann
- Gerhard Domagk Institute for Pathology, University Hospital Münster, Germany
| | - Federico Comoglio
- Cambridge University Department of Haematology, Cambridge Institute of Medical Research, Cambridge, UK
| | - Martin-Leo Hansmann
- Senckenberg Institute of Pathology, University of Frankfurt, Frankfurt, Germany
| | - Alexander F Yakunin
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Canada
| | - Gerd Geisslinger
- Pharmazentrum frankfurt/ZAFES, Institute of Clinical Pharmacology, Goethe University of Frankfurt, Frankfurt, Germany.,Fraunhofer Institute for Molecular Biology and Applied Ecology (IME), Project Group Translational Medicine and Pharmacology (TMP), Frankfurt, Germany
| | - Philipp Ströbel
- Institute of Pathology, University Medical Center, Göttingen, Germany
| | - Nerea Ferreirós
- Pharmazentrum frankfurt/ZAFES, Institute of Clinical Pharmacology, Goethe University of Frankfurt, Frankfurt, Germany
| | - Hubert Serve
- Department of Medicine II, Hematology and Oncology, Goethe University of Frankfurt, Frankfurt, Germany.,German Cancer Consortium partner site, German Cancer Research Center, Heidelberg, Germany
| | - Oliver T Keppler
- Institute of Medical Virology, University of Frankfurt, Frankfurt, Germany.,Max von Pettenkofer Institute, Department of Virology, Ludwig Maximilian University of Munich, Munich, Germany
| | - Jindrich Cinatl
- Institute of Medical Virology, University of Frankfurt, Frankfurt, Germany
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22
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Badia R, Pujantell M, Riveira-Muñoz E, Puig T, Torres-Torronteras J, Martí R, Clotet B, Ampudia RM, Vives-Pi M, Esté JA, Ballana E. The G1/S Specific Cyclin D2 Is a Regulator of HIV-1 Restriction in Non-proliferating Cells. PLoS Pathog 2016; 12:e1005829. [PMID: 27541004 PMCID: PMC4991798 DOI: 10.1371/journal.ppat.1005829] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Accepted: 07/27/2016] [Indexed: 01/09/2023] Open
Abstract
Macrophages are a heterogeneous cell population strongly influenced by differentiation stimuli that become susceptible to HIV-1 infection after inactivation of the restriction factor SAMHD1 by cyclin-dependent kinases (CDK). Here, we have used primary human monocyte-derived macrophages differentiated through different stimuli to evaluate macrophage heterogeneity on cell activation and proliferation and susceptibility to HIV-1 infection. Stimulation of monocytes with GM-CSF induces a non-proliferating macrophage population highly restrictive to HIV-1 infection, characterized by the upregulation of the G1/S-specific cyclin D2, known to control early steps of cell cycle progression. Knockdown of cyclin D2, enhances HIV-1 replication in GM-CSF macrophages through inactivation of SAMHD1 restriction factor by phosphorylation. Co-immunoprecipitation experiments show that cyclin D2 forms a complex with CDK4 and p21, a factor known to restrict HIV-1 replication by affecting the function of the downstream cascade that leads to SAMHD1 deactivation. Thus, we demonstrate that cyclin D2 acts as regulator of cell cycle proteins affecting SAMHD1-mediated HIV-1 restriction in non-proliferating macrophages.
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Affiliation(s)
- Roger Badia
- AIDS Research Institute-IrsiCaixa, Hospital Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain
- Health Research Institute Germans Trias i Pujol (IGTP), Hospital Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain
| | - Maria Pujantell
- AIDS Research Institute-IrsiCaixa, Hospital Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain
- Health Research Institute Germans Trias i Pujol (IGTP), Hospital Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain
| | - Eva Riveira-Muñoz
- AIDS Research Institute-IrsiCaixa, Hospital Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain
- Health Research Institute Germans Trias i Pujol (IGTP), Hospital Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain
| | - Teresa Puig
- AIDS Research Institute-IrsiCaixa, Hospital Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain
- Health Research Institute Germans Trias i Pujol (IGTP), Hospital Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain
| | - Javier Torres-Torronteras
- Research Group on Neuromuscular and Mitochondrial Disorders, Vall d’Hebron Institut de Recerca, Universitat Autònoma de Barcelona, and Biomedical Network Research Centre on Rare Diseases (CIBERER), Instituto de Salud Carlos III, Barcelona, Spain
| | - Ramón Martí
- Research Group on Neuromuscular and Mitochondrial Disorders, Vall d’Hebron Institut de Recerca, Universitat Autònoma de Barcelona, and Biomedical Network Research Centre on Rare Diseases (CIBERER), Instituto de Salud Carlos III, Barcelona, Spain
| | - Bonaventura Clotet
- AIDS Research Institute-IrsiCaixa, Hospital Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain
- Health Research Institute Germans Trias i Pujol (IGTP), Hospital Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain
| | - Rosa M. Ampudia
- Health Research Institute Germans Trias i Pujol (IGTP), Hospital Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain
- Biomedical Network Research Centre on Diabetes and Associated Metabolic Diseases (CIBERDEM), Instituto de Salud Carlos III, Barcelona, Spain
| | - Marta Vives-Pi
- Health Research Institute Germans Trias i Pujol (IGTP), Hospital Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain
- Biomedical Network Research Centre on Diabetes and Associated Metabolic Diseases (CIBERDEM), Instituto de Salud Carlos III, Barcelona, Spain
| | - José A. Esté
- AIDS Research Institute-IrsiCaixa, Hospital Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain
- Health Research Institute Germans Trias i Pujol (IGTP), Hospital Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain
- * E-mail: (JAE); (EB)
| | - Ester Ballana
- AIDS Research Institute-IrsiCaixa, Hospital Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain
- Health Research Institute Germans Trias i Pujol (IGTP), Hospital Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain
- * E-mail: (JAE); (EB)
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Ruiz A, Pauls E, Badia R, Torres-Torronteras J, Riveira-Muñoz E, Clotet B, Martí R, Ballana E, Esté JA. Cyclin D3-dependent control of the dNTP pool and HIV-1 replication in human macrophages. Cell Cycle 2016; 14:1657-65. [PMID: 25927932 DOI: 10.1080/15384101.2015.1030558] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
Cyclins control the activation of cyclin-dependent kinases (CDK), which in turn, control the cell cycle and cell division. Intracellular availability of deoxynucleotides (dNTP) plays a fundamental role in cell cycle progression. SAM domain and HD domain-containing protein 1 (SAMHD1) degrades nucleotide triphosphates and controls the size of the dNTP pool. SAMHD1 activity appears to be controlled by CDK. Here, we show that knockdown of cyclin D3 a partner of CDK6 and E2 a partner of CDK2 had a major impact in SAMHD1 phosphorylation and inactivation and led to decreased dNTP levels and inhibition of HIV-1 at the reverse transcription step in primary human macrophages. The effect of cyclin D3 RNA interference was lost after degradation of SAMHD1 by HIV-2 Vpx, demonstrating the specificity of the mechanism. Cyclin D3 inhibition correlated with decreased activation of CDK2. Our results confirm the fundamental role of the CDK6-cyclin D3 pair in controlling CDK2-dependent SAMHD1 phosphorylation and dNTP pool in primary macrophages.
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Affiliation(s)
- Alba Ruiz
- a AIDS Research Institute-IrsiCaixa and AIDS Unit; Hospital Germans Trias i Pujol; Universitat Autonoma de Barcelona ; Badalona , Spain
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24
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Badia R, Angulo G, Riveira-Muñoz E, Pujantell M, Puig T, Ramirez C, Torres-Torronteras J, Martí R, Pauls E, Clotet B, Ballana E, Esté JA. Inhibition of herpes simplex virus type 1 by the CDK6 inhibitor PD-0332991 (palbociclib) through the control of SAMHD1. J Antimicrob Chemother 2015; 71:387-94. [PMID: 26542306 DOI: 10.1093/jac/dkv363] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2015] [Accepted: 10/02/2015] [Indexed: 12/14/2022] Open
Abstract
OBJECTIVES Sterile α motif and histidine-aspartate domain-containing protein 1 (SAMHD1) has been shown to restrict retroviruses and DNA viruses by decreasing the pool of intracellular deoxynucleotides. In turn, SAMHD1 is controlled by cyclin-dependent kinases (CDK) that regulate the cell cycle and cell proliferation. Here, we explore the effect of CDK6 inhibitors on the replication of herpes simplex virus type 1 (HSV-1) in primary monocyte-derived macrophages (MDM). METHODS MDM were treated with palbociclib, a selective CDK4/6 inhibitor, and then infected with a GFP-expressing HSV-1. Intracellular deoxynucleotide triphosphate (dNTP) content was determined using a polymerase-based method. RESULTS CDK6 inhibitor palbociclib blocked SAMHD1 phosphorylation, intracellular dNTP levels and HSV-1 replication in MDM at subtoxic concentrations. Treatment of MDM with palbociclib reduced CDK2 activation, measured as the phosphorylation of the T-loop at Thr160. The antiviral activity of palbociclib was lost when SAMHD1 was degraded by viral protein X. Similarly, palbociclib did not block HSV-1 replication in SAMHD1-negative Vero cells at subtoxic concentrations, providing further evidence for a role of SAMHD1 in mediating the antiviral effect. CONCLUSIONS SAMHD1-mediated HSV-1 restriction is controlled by CDK and points to a preferential role for CDK6 and CDK2 as mediators of SAMHD1 activation. Similarly, the restricting activity of SAMHD1 against DNA viruses suggests that control of dNTP availability is the major determinant of its antiviral activity. This is the first study describing the anti-HSV-1 activity of palbociclib.
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Affiliation(s)
- Roger Badia
- AIDS Research Institute - IrsiCaixa, and Health Research Institute Germans Trias i Pujol (IGTP), Hospital Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain
| | - Guillem Angulo
- AIDS Research Institute - IrsiCaixa, and Health Research Institute Germans Trias i Pujol (IGTP), Hospital Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain
| | - Eva Riveira-Muñoz
- AIDS Research Institute - IrsiCaixa, and Health Research Institute Germans Trias i Pujol (IGTP), Hospital Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain
| | - Maria Pujantell
- AIDS Research Institute - IrsiCaixa, and Health Research Institute Germans Trias i Pujol (IGTP), Hospital Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain
| | - Teresa Puig
- AIDS Research Institute - IrsiCaixa, and Health Research Institute Germans Trias i Pujol (IGTP), Hospital Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain
| | - Cristina Ramirez
- AIDS Research Institute - IrsiCaixa, and Health Research Institute Germans Trias i Pujol (IGTP), Hospital Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain
| | - Javier Torres-Torronteras
- Research Group on Neuromuscular and Mitochondrial Disorders, Vall d'Hebron Institut de Recerca, Universitat Autònoma de Barcelona, and Biomedical Network Research Centre on Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
| | - Ramón Martí
- Research Group on Neuromuscular and Mitochondrial Disorders, Vall d'Hebron Institut de Recerca, Universitat Autònoma de Barcelona, and Biomedical Network Research Centre on Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
| | - Eduardo Pauls
- AIDS Research Institute - IrsiCaixa, and Health Research Institute Germans Trias i Pujol (IGTP), Hospital Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain
| | - Bonaventura Clotet
- AIDS Research Institute - IrsiCaixa, and Health Research Institute Germans Trias i Pujol (IGTP), Hospital Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain
| | - Ester Ballana
- AIDS Research Institute - IrsiCaixa, and Health Research Institute Germans Trias i Pujol (IGTP), Hospital Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain
| | - José A Esté
- AIDS Research Institute - IrsiCaixa, and Health Research Institute Germans Trias i Pujol (IGTP), Hospital Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain
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Hollenbaugh JA, Schader SM, Schinazi RF, Kim B. Differential regulatory activities of viral protein X for anti-viral efficacy of nucleos(t)ide reverse transcriptase inhibitors in monocyte-derived macrophages and activated CD4(+) T cells. Virology 2015; 485:313-21. [PMID: 26319213 PMCID: PMC4619155 DOI: 10.1016/j.virol.2015.08.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Revised: 07/27/2015] [Accepted: 08/08/2015] [Indexed: 01/05/2023]
Abstract
Vpx encoded by HIV-2 and SIVsm enhances retroviral reverse transcription in macrophages in vitro by mediating the degradation of the host SAMHD1 protein that hydrolyzes dNTPs and by elevating cellular dNTP levels. Here we employed RT-SHIV constructs (SIV encoding HIV-1 RT) to investigate the contribution of Vpx to the potency of NRTIs, which compete against dNTPs, in monocyte-derived macrophages (MDMs) and activated CD4(+) T cells. Relative to HIV-1, both SIV and RT-SHIV exhibited reduced sensitivities to AZT, 3TC and TDF in MDMs but not in activated CD4(+) T cells. However, when SIV and RT-SHIV constructs not coding for Vpx were utilized, we observed greater sensitivities to all NRTIs tested using activated CD4(+) T cells relative to the Vpx-coding counterparts. This latter phenomenon was observed for AZT only when using MDMs. Our data suggest that Vpx in RT-SHIVs may underestimate the antiviral efficacy of NRTIs in a cell type dependent manner.
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Affiliation(s)
- Joseph A Hollenbaugh
- Center for Drug Discovery, Department of Pediatrics, Emory University, Atlanta, GA, USA
| | - Susan M Schader
- Center for Drug Discovery, Department of Pediatrics, Emory University, Atlanta, GA, USA
| | - Raymond F Schinazi
- Center for Drug Discovery, Department of Pediatrics, Emory University, Atlanta, GA, USA; Veterans Affairs Medical Center, Atlanta, GA, USA
| | - Baek Kim
- Center for Drug Discovery, Department of Pediatrics, Emory University, Atlanta, GA, USA; College of Pharmacy, Kyung Hee University, Seoul, South Korea.
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26
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Ballana E, Esté JA. SAMHD1: at the crossroads of cell proliferation, immune responses, and virus restriction. Trends Microbiol 2015; 23:680-692. [PMID: 26439297 DOI: 10.1016/j.tim.2015.08.002] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Revised: 07/28/2015] [Accepted: 08/07/2015] [Indexed: 12/31/2022]
Abstract
SAMHD1 is a triphosphohydrolase enzyme that controls the intracellular level of deoxyribonucleoside triphosphates (dNTPs) and plays a role in innate immune sensing and autoimmune disease. SAMHD1 has also been identified as an intrinsic virus restriction factor, inactivated through degradation by HIV-2 Vpx or through a post-transcriptional regulatory mechanism. Phosphorylation of SAMHD1 by cyclin-dependent kinases has been strongly associated with inactivation of the virus restriction mechanism, providing an association between virus replication and cell proliferation. Tight regulation of cell proliferation suggests that viruses, particularly HIV-1 replication, latency, and reactivation, may be similarly controlled by multiple checkpoint mechanisms that, in turn, regulate dNTP levels. In this review, we discuss how SAMHD1 is a viral restriction factor, the mechanism associated with viral restriction, the pathway leading to its inactivation in proliferating cells, and how strategies aimed at controlling virus restriction could lead to a functional cure for HIV.
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Affiliation(s)
- Ester Ballana
- AIDS Research Institute-IrsiCaixa and Health Research Institute Germans Trias i Pujol (IGTP), Hospital Germans Trias i Pujol, Universitat Autònoma de Barcelona, 08916 Badalona, Spain
| | - José A Esté
- AIDS Research Institute-IrsiCaixa and Health Research Institute Germans Trias i Pujol (IGTP), Hospital Germans Trias i Pujol, Universitat Autònoma de Barcelona, 08916 Badalona, Spain.
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27
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Kohnken R, Kodigepalli KM, Wu L. Regulation of deoxynucleotide metabolism in cancer: novel mechanisms and therapeutic implications. Mol Cancer 2015; 14:176. [PMID: 26416562 PMCID: PMC4587406 DOI: 10.1186/s12943-015-0446-6] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Accepted: 09/18/2015] [Indexed: 11/16/2022] Open
Abstract
Regulation of intracellular deoxynucleoside triphosphate (dNTP) pool is critical to genomic stability and cancer development. Imbalanced dNTP pools can lead to enhanced mutagenesis and cell proliferation resulting in cancer development. Therapeutic agents that target dNTP synthesis and metabolism are commonly used in treatment of several types of cancer. Despite several studies, the molecular mechanisms that regulate the intracellular dNTP levels and maintain their homeostasis are not completely understood. The discovery of SAMHD1 as the first mammalian dNTP triphosphohydrolase provided new insight into the mechanisms of dNTP regulation. SAMHD1 maintains the homeostatic dNTP levels that regulate DNA replication and damage repair. Recent progress indicates that gene mutations and epigenetic mechanisms lead to downregulation of SAMHD1 activity or expression in multiple cancers. Impaired SAMHD1 function can cause increased dNTP pool resulting in genomic instability and cell-cycle progression, thereby facilitating cancer cell proliferation. This review summarizes the latest advances in understanding the importance of dNTP metabolism in cancer development and the novel function of SAMHD1 in regulating this process.
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Affiliation(s)
- Rebecca Kohnken
- Center for Retrovirus Research, Department of Veterinary Biosciences, The Ohio State University, 1900 Coffey Road, Columbus, OH, 43210, USA
| | - Karthik M Kodigepalli
- Center for Retrovirus Research, Department of Veterinary Biosciences, The Ohio State University, 1900 Coffey Road, Columbus, OH, 43210, USA
| | - Li Wu
- Center for Retrovirus Research, Department of Veterinary Biosciences, The Ohio State University, 1900 Coffey Road, Columbus, OH, 43210, USA. .,Department of Microbial Infection and Immunity, The Ohio State University, Columbus, OH, 43210, USA. .,Comprehensive Cancer Center, The Ohio State University, Columbus, OH, 43210, USA.
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28
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A continuous enzyme-coupled assay for triphosphohydrolase activity of HIV-1 restriction factor SAMHD1. Antimicrob Agents Chemother 2014; 59:186-92. [PMID: 25331707 PMCID: PMC4291348 DOI: 10.1128/aac.03903-14] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The development of deoxynucleoside triphosphate (dNTP)-based drugs requires a quantitative understanding of any inhibition, activation, or hydrolysis by off-target cellular enzymes. SAMHD1 is a regulatory dNTP-triphosphohydrolase that inhibits HIV-1 replication in human myeloid cells. We describe here an enzyme-coupled assay for quantifying the activation, inhibition, and hydrolysis of dNTPs, nucleotide analogues, and nucleotide analogue inhibitors by triphosphohydrolase enzymes. The assay facilitates mechanistic studies of triphosphohydrolase enzymes and the quantification of off-target effects of nucleotide-based antiviral and chemotherapeutic agents.
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