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Jiang D, Soo N, Tan CY, Dankwa S, Wang HY, Theriot BS, Ardeshir A, Siddiqui NY, Van Rompay KKA, De Paris K, Permar SR, Goswami R, Surana NK. Commensal bacteria inhibit viral infections via a tryptophan metabolite. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.21.589969. [PMID: 38659737 PMCID: PMC11042330 DOI: 10.1101/2024.04.21.589969] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/26/2024]
Abstract
There is growing appreciation that commensal bacteria impact the outcome of viral infections, though the specific bacteria and their underlying mechanisms remain poorly understood. Studying a simian-human immunodeficiency virus (SHIV)-challenged cohort of pediatric nonhuman primates, we bioinformatically associated Lactobacillus gasseri and the bacterial family Lachnospiraceae with enhanced resistance to infection. We experimentally validated these findings by demonstrating two different Lachnospiraceae isolates, Clostridium immunis and Ruminococcus gnavus, inhibited HIV replication in vitro and ex vivo. Given the link between tryptophan catabolism and HIV disease severity, we found that an isogenic mutant of C. immunis that lacks the aromatic amino acid aminotransferase (ArAT) gene, which is key to metabolizing tryptophan into 3-indolelactic acid (ILA), no longer inhibits HIV infection. Intriguingly, we confirmed that a second commensal bacterium also inhibited HIV in an ArAT-dependent manner, thus establishing the generalizability of this finding. In addition, we found that purified ILA inhibited HIV infection by agonizing the aryl hydrocarbon receptor (AhR). Given that the AhR has been implicated in the control of multiple viral infections, we demonstrated that C. immunis also inhibited human cytomegalovirus (HCMV) infection in an ArAT-dependent manner. Importantly, metagenomic analysis of individuals at-risk for HIV revealed that those who ultimately acquired HIV had a lower fecal abundance of the bacterial ArAT gene compared to individuals who did not, which indicates our findings translate to humans. Taken together, our results provide mechanistic insights into how commensal bacteria decrease susceptibility to viral infections. Moreover, we have defined a microbiota-driven antiviral pathway that offers the potential for novel therapeutic strategies targeting a broad spectrum of viral pathogens.
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Lin C, Kuffour EO, Li T, Gertzen CGW, Kaiser J, Luedde T, König R, Gohlke H, Münk C. The ISG15-Protease USP18 Is a Pleiotropic Enhancer of HIV-1 Replication. Viruses 2024; 16:485. [PMID: 38675828 PMCID: PMC11053637 DOI: 10.3390/v16040485] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2024] [Revised: 03/19/2024] [Accepted: 03/20/2024] [Indexed: 04/28/2024] Open
Abstract
The innate immune response to viruses is formed in part by interferon (IFN)-induced restriction factors, including ISG15, p21, and SAMHD1. IFN production can be blocked by the ISG15-specific protease USP18. HIV-1 has evolved to circumvent host immune surveillance. This mechanism might involve USP18. In our recent studies, we demonstrate that HIV-1 infection induces USP18, which dramatically enhances HIV-1 replication by abrogating the antiviral function of p21. USP18 downregulates p21 by accumulating misfolded dominant negative p53, which inactivates wild-type p53 transactivation, leading to the upregulation of key enzymes involved in de novo dNTP biosynthesis pathways and inactivated SAMHD1. Despite the USP18-mediated increase in HIV-1 DNA in infected cells, it is intriguing to note that the cGAS-STING-mediated sensing of the viral DNA is abrogated. Indeed, the expression of USP18 or knockout of ISG15 inhibits the sensing of HIV-1. We demonstrate that STING is ISGylated at residues K224, K236, K289, K347, K338, and K370. The inhibition of STING K289-linked ISGylation suppresses its oligomerization and IFN induction. We propose that human USP18 is a novel factor that potentially contributes in multiple ways to HIV-1 replication.
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Affiliation(s)
- Chaohui Lin
- Clinic of Gastroenterology, Hepatology and Infectious Diseases, Medical Faculty, Heinrich Heine University Düsseldorf, 40225 Düsseldorf, Germany; (C.L.); (E.O.K.); (T.L.); (T.L.)
| | - Edmund Osei Kuffour
- Clinic of Gastroenterology, Hepatology and Infectious Diseases, Medical Faculty, Heinrich Heine University Düsseldorf, 40225 Düsseldorf, Germany; (C.L.); (E.O.K.); (T.L.); (T.L.)
| | - Taolan Li
- Clinic of Gastroenterology, Hepatology and Infectious Diseases, Medical Faculty, Heinrich Heine University Düsseldorf, 40225 Düsseldorf, Germany; (C.L.); (E.O.K.); (T.L.); (T.L.)
| | - Christoph G. W. Gertzen
- Institute for Pharmaceutical and Medicinal Chemistry, Heinrich Heine University Düsseldorf, 40225 Düsseldorf, Germany; (C.G.W.G.); (J.K.); (H.G.)
| | - Jesko Kaiser
- Institute for Pharmaceutical and Medicinal Chemistry, Heinrich Heine University Düsseldorf, 40225 Düsseldorf, Germany; (C.G.W.G.); (J.K.); (H.G.)
| | - Tom Luedde
- Clinic of Gastroenterology, Hepatology and Infectious Diseases, Medical Faculty, Heinrich Heine University Düsseldorf, 40225 Düsseldorf, Germany; (C.L.); (E.O.K.); (T.L.); (T.L.)
| | - Renate König
- Host-Pathogen Interactions, Paul-Ehrlich-Institut, 63225 Langen, Germany;
| | - Holger Gohlke
- Institute for Pharmaceutical and Medicinal Chemistry, Heinrich Heine University Düsseldorf, 40225 Düsseldorf, Germany; (C.G.W.G.); (J.K.); (H.G.)
- Institute of Bio- and Geosciences (IBG-4: Bioinformatics), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Carsten Münk
- Clinic of Gastroenterology, Hepatology and Infectious Diseases, Medical Faculty, Heinrich Heine University Düsseldorf, 40225 Düsseldorf, Germany; (C.L.); (E.O.K.); (T.L.); (T.L.)
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Kumari N, Ahmad A, Berto-Junior C, Ivanov A, Wen F, Lin X, Diaz S, Okpala I, Taylor JG, Jerebtsova M, Nekhai S. Antiviral response and HIV-1 inhibition in sickle cell disease. iScience 2024; 27:108813. [PMID: 38318349 PMCID: PMC10839265 DOI: 10.1016/j.isci.2024.108813] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 11/03/2023] [Accepted: 01/02/2024] [Indexed: 02/07/2024] Open
Abstract
Sickle cell disease (SCD) is characterized by hemolysis, vaso-occlusion, and ischemia. HIV-1 infection was previously shown to be suppressed in SCD PBMCs. Here, we report that HIV-1 suppression is attributed to the increased expression of iron, hypoxia, and interferon-induced innate antiviral factors. Inhibition of upregulated antiviral genes, HMOX-1, CDKN1A, and CH25H, increased HIV-1 replication in SCD PBMCs, suggesting their critical role in HIV-1 suppression. Levels of IFN-β were elevated in SCD patients. Sickle cell hemoglobin (HbS) treatment of THP-1-derived and primary monocyte-derived macrophages induced production of IFN-β, upregulated antiviral gene expression, and suppressed HIV-1 infection. Infection with mouse-adapted EcoHIV was suppressed in the SCD mice that also exhibited elevated levels of antiviral restriction factors. Our findings suggest that hemolysis and release of HbS leads to the induction of IFN-β production, induction of cellular antiviral state by the expression of iron and IFN-driven factors, and suppression of HIV-1 infection.
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Affiliation(s)
- Namita Kumari
- Center for Sickle Cell Disease, Howard University, Washington, DC, USA
- Department of Medicine, Howard University, Washington, DC, USA
| | - Asrar Ahmad
- Center for Sickle Cell Disease, Howard University, Washington, DC, USA
| | - Clemilson Berto-Junior
- Center for Sickle Cell Disease, Howard University, Washington, DC, USA
- Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Andrey Ivanov
- Center for Sickle Cell Disease, Howard University, Washington, DC, USA
| | - Fayuan Wen
- Center for Sickle Cell Disease, Howard University, Washington, DC, USA
| | - Xionghao Lin
- Center for Sickle Cell Disease, Howard University, Washington, DC, USA
| | - Sharmin Diaz
- Center for Sickle Cell Disease, Howard University, Washington, DC, USA
| | | | - James G. Taylor
- Center for Sickle Cell Disease, Howard University, Washington, DC, USA
- Department of Medicine, Howard University, Washington, DC, USA
- Department of Food and Human Nutritional Sciences, University of Manitoba, Winnipeg, Canada
| | | | - Sergei Nekhai
- Center for Sickle Cell Disease, Howard University, Washington, DC, USA
- Department of Medicine, Howard University, Washington, DC, USA
- Department of Microbiology, Howard University, Washington, DC, USA
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4
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Gutiérrez-Chamorro L, Felip E, Castellà E, Quiroga V, Ezeonwumelu IJ, Angelats L, Esteve A, Perez-Roca L, Martínez-Cardús A, Fernandez PL, Ferrando-Díez A, Pous A, Bergamino M, Cirauqui B, Romeo M, Teruel I, Mesia R, Clotet B, Riveira-Muñoz E, Margelí M, Ballana E. SAMHD1 expression is a surrogate marker of immune infiltration and determines prognosis after neoadjuvant chemotherapy in early breast cancer. Cell Oncol (Dordr) 2024; 47:189-208. [PMID: 37667113 PMCID: PMC10899429 DOI: 10.1007/s13402-023-00862-1] [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] [Accepted: 08/07/2023] [Indexed: 09/06/2023] Open
Abstract
PURPOSE The lack of validated surrogate biomarkers is still an unmet clinical need in the management of early breast cancer cases that do not achieve complete pathological response after neoadjuvant chemotherapy (NACT). Here, we describe and validate the use of SAMHD1 expression as a prognostic biomarker in residual disease in vivo and in vitro. METHODS SAMHD1 expression was evaluated in a clinical cohort of early breast cancer patients with stage II-III treated with NACT. Heterotypic 3D cultures including tumor and immune cells were used to investigate the molecular mechanisms responsible of SAMHD1 depletion through whole transcriptomic profiling, immune infiltration capacity and subsequent delineation of dysregulated immune signaling pathways. RESULTS SAMHD1 expression was associated to increased risk of recurrence and higher Ki67 levels in post-NACT tumor biopsies of breast cancer patients with residual disease. Survival analysis showed that SAMHD1-expressing tumors presented shorter time-to-progression and overall survival than SAMHD1 negative cases, suggesting that SAMHD1 expression is a relevant prognostic factor in breast cancer. Whole-transcriptomic profiling of SAMHD1-depleted tumors identified downregulation of IL-12 signaling pathway as the molecular mechanism determining breast cancer prognosis. The reduced interleukin signaling upon SAMHD1 depletion induced changes in immune cell infiltration capacity in 3D heterotypic in vitro culture models, confirming the role of the SAMHD1 as a regulator of breast cancer prognosis through the induction of changes in immune response and tumor microenvironment. CONCLUSION SAMHD1 expression is a novel prognostic biomarker in early breast cancer that impacts immune-mediated signaling and differentially regulates inflammatory intra-tumoral response.
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Affiliation(s)
- Lucía Gutiérrez-Chamorro
- 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
| | - Eudald Felip
- 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
- Medical Oncology Department, Catalan Institut of Oncology (ICO)-Badalona, B-ARGO (Badalona Applied Research Group in Oncology) and IGTP (Health Research Institute Germans Trias i Pujol), Universitat Autònoma de Barcelona, 08916, Badalona, Spain
| | - Eva Castellà
- Department of Pathology, Hospital Germans Trias i Pujol, IGTP (Health Research Institute Germans Trias I Pujol), Universitat Autònoma de Barcelona, 08916, Badalona, Spain
| | - Vanessa Quiroga
- Medical Oncology Department, Catalan Institut of Oncology (ICO)-Badalona, B-ARGO (Badalona Applied Research Group in Oncology) and IGTP (Health Research Institute Germans Trias i Pujol), Universitat Autònoma de Barcelona, 08916, Badalona, Spain
| | - Ifeanyi Jude Ezeonwumelu
- 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
| | - Laura Angelats
- Medical Oncology Department, Catalan Institut of Oncology (ICO)-Badalona, B-ARGO (Badalona Applied Research Group in Oncology) and IGTP (Health Research Institute Germans Trias i Pujol), Universitat Autònoma de Barcelona, 08916, Badalona, Spain
| | - Anna Esteve
- Medical Oncology Department, Catalan Institut of Oncology (ICO)-Badalona, B-ARGO (Badalona Applied Research Group in Oncology) and IGTP (Health Research Institute Germans Trias i Pujol), Universitat Autònoma de Barcelona, 08916, Badalona, Spain
| | - Laia Perez-Roca
- Banc de Tumors, Health Research Institute Germans Trias i Pujol (IGTP), Hospital Germans Trias i Pujol, Universitat Autònoma de Barcelona, 08916, Badalona, Spain
| | - Anna Martínez-Cardús
- Medical Oncology Department, Catalan Institut of Oncology (ICO)-Badalona, B-ARGO (Badalona Applied Research Group in Oncology) and IGTP (Health Research Institute Germans Trias i Pujol), Universitat Autònoma de Barcelona, 08916, Badalona, Spain
| | - Pedro Luis Fernandez
- Department of Pathology, Hospital Germans Trias i Pujol, IGTP (Health Research Institute Germans Trias I Pujol), Universitat Autònoma de Barcelona, 08916, Badalona, Spain
| | - Angelica Ferrando-Díez
- Medical Oncology Department, Catalan Institut of Oncology (ICO)-Badalona, B-ARGO (Badalona Applied Research Group in Oncology) and IGTP (Health Research Institute Germans Trias i Pujol), Universitat Autònoma de Barcelona, 08916, Badalona, Spain
| | - Anna Pous
- Medical Oncology Department, Catalan Institut of Oncology (ICO)-Badalona, B-ARGO (Badalona Applied Research Group in Oncology) and IGTP (Health Research Institute Germans Trias i Pujol), Universitat Autònoma de Barcelona, 08916, Badalona, Spain
| | - Milana Bergamino
- Medical Oncology Department, Catalan Institut of Oncology (ICO)-Badalona, B-ARGO (Badalona Applied Research Group in Oncology) and IGTP (Health Research Institute Germans Trias i Pujol), Universitat Autònoma de Barcelona, 08916, Badalona, Spain
| | - Beatriz Cirauqui
- Medical Oncology Department, Catalan Institut of Oncology (ICO)-Badalona, B-ARGO (Badalona Applied Research Group in Oncology) and IGTP (Health Research Institute Germans Trias i Pujol), Universitat Autònoma de Barcelona, 08916, Badalona, Spain
| | - Marga Romeo
- Medical Oncology Department, Catalan Institut of Oncology (ICO)-Badalona, B-ARGO (Badalona Applied Research Group in Oncology) and IGTP (Health Research Institute Germans Trias i Pujol), Universitat Autònoma de Barcelona, 08916, Badalona, Spain
| | - Iris Teruel
- Medical Oncology Department, Catalan Institut of Oncology (ICO)-Badalona, B-ARGO (Badalona Applied Research Group in Oncology) and IGTP (Health Research Institute Germans Trias i Pujol), Universitat Autònoma de Barcelona, 08916, Badalona, Spain
| | - Ricard Mesia
- Medical Oncology Department, Catalan Institut of Oncology (ICO)-Badalona, B-ARGO (Badalona Applied Research Group in Oncology) and IGTP (Health Research Institute Germans Trias i Pujol), Universitat Autònoma de Barcelona, 08916, 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, 08916, 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, 08916, Badalona, Spain
| | - Mireia Margelí
- Medical Oncology Department, Catalan Institut of Oncology (ICO)-Badalona, B-ARGO (Badalona Applied Research Group in Oncology) and IGTP (Health Research Institute Germans Trias i Pujol), Universitat Autònoma de Barcelona, 08916, 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, 08916, Badalona, Spain.
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Tsai MHC, Caswell SJ, Morris ER, Mann MC, Pennell S, Kelly G, Groom HCT, Taylor IA, Bishop KN. Attenuation of reverse transcriptase facilitates SAMHD1 restriction of HIV-1 in cycling cells. Retrovirology 2023; 20:5. [PMID: 37127613 PMCID: PMC10150492 DOI: 10.1186/s12977-023-00620-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Accepted: 04/06/2023] [Indexed: 05/03/2023] Open
Abstract
BACKGROUND SAMHD1 is a deoxynucleotide triphosphohydrolase that restricts replication of HIV-1 in differentiated leucocytes. HIV-1 is not restricted in cycling cells and it has been proposed that this is due to phosphorylation of SAMHD1 at T592 in these cells inactivating the enzymatic activity. To distinguish between theories for how SAMHD1 restricts HIV-1 in differentiated but not cycling cells, we analysed the effects of substitutions at T592 on restriction and dNTP levels in both cycling and differentiated cells as well as tetramer stability and enzymatic activity in vitro. RESULTS We first showed that HIV-1 restriction was not due to SAMHD1 nuclease activity. We then characterised a panel of SAMHD1 T592 mutants and divided them into three classes. We found that a subset of mutants lost their ability to restrict HIV-1 in differentiated cells which generally corresponded with a decrease in triphosphohydrolase activity and/or tetramer stability in vitro. Interestingly, no T592 mutants were able to restrict WT HIV-1 in cycling cells, despite not being regulated by phosphorylation and retaining their ability to hydrolyse dNTPs. Lowering dNTP levels by addition of hydroxyurea did not give rise to restriction. Compellingly however, HIV-1 RT mutants with reduced affinity for dNTPs were significantly restricted by wild-type and T592 mutant SAMHD1 in both cycling U937 cells and Jurkat T-cells. Restriction correlated with reverse transcription levels. CONCLUSIONS Altogether, we found that the amino acid at residue 592 has a strong effect on tetramer formation and, although this is not a simple "on/off" switch, this does correlate with the ability of SAMHD1 to restrict HIV-1 replication in differentiated cells. However, preventing phosphorylation of SAMHD1 and/or lowering dNTP levels by adding hydroxyurea was not enough to restore restriction in cycling cells. Nonetheless, lowering the affinity of HIV-1 RT for dNTPs, showed that restriction is mediated by dNTP levels and we were able to observe for the first time that SAMHD1 is active and capable of inhibiting HIV-1 replication in cycling cells, if the affinity of RT for dNTPs is reduced. This suggests that the very high affinity of HIV-1 RT for dNTPs prevents HIV-1 restriction by SAMHD1 in cycling cells.
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Affiliation(s)
- Ming-Han C Tsai
- Retroviral Replication Laboratory, The Francis Crick Institute, London, UK
- LabGenius, London, UK
| | - Sarah J Caswell
- Macromolecular Structure Laboratory, The Francis Crick Institute, London, UK
- AstraZeneca, Granta Park, Cambridge, UK
| | - Elizabeth R Morris
- Macromolecular Structure Laboratory, The Francis Crick Institute, London, UK
- Department of Biosciences, University of Durham, Durham, UK
| | - Melanie C Mann
- Retroviral Replication Laboratory, The Francis Crick Institute, London, UK
- Sartorius, Ulm, Germany
| | - Simon Pennell
- Structural Biology of DNA-Damage Signalling Laboratory, The Francis Crick Institute, London, UK
- MRC London Institute of Medical Sciences, London, UK
| | - Geoff Kelly
- The Medical Research Council Biomedical NMR Centre, The Francis Crick Institute, London, UK
| | - Harriet C T Groom
- Retroviral Replication Laboratory, The Francis Crick Institute, London, UK
- Department of Medicine, University of Cambridge, Cambridge, UK
| | - Ian A Taylor
- Macromolecular Structure Laboratory, The Francis Crick Institute, London, UK
| | - Kate N Bishop
- Retroviral Replication Laboratory, The Francis Crick Institute, London, UK.
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Sharifi HJ, Paine DN, Fazzari VA, Tipple AF, Patterson E, de Noronha CMC. Sulforaphane Reduces SAMHD1 Phosphorylation To Protect Macrophages from HIV-1 Infection. J Virol 2022; 96:e0118722. [PMID: 36377871 PMCID: PMC9749475 DOI: 10.1128/jvi.01187-22] [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: 07/29/2022] [Accepted: 10/24/2022] [Indexed: 11/16/2022] Open
Abstract
The cellular protein SAMHD1 is important for DNA repair, suppressing LINE elements, controlling deoxynucleoside triphosphate (dNTP) concentrations, maintaining HIV-1 latency, and preventing excessive type I interferon responses. SAMHD1 is also a potent inhibitor of HIV-1 and other significant viral pathogens. Infection restriction is due in part to the deoxynucleoside triphosphatase (dNTPase) activity of SAMHD1 but is also mediated through a dNTPase-independent mechanism that has been described but not explored. The phosphorylation of SAMHD1 at threonine 592 (T592) controls many of its functions. Retroviral restriction, irrespective of dNTPase activity, is linked to unphosphorylated T592. Sulforaphane (SFN), an isothiocyanate, protects macrophages from HIV infection by mobilizing the transcription factor and antioxidant response regulator Nrf2. Here, we show that SFN and other clinically relevant Nrf2 mobilizers reduce SAMHD1 T592 phosphorylation to protect macrophages from HIV-1. We further show that SFN, through Nrf2, triggers the upregulation of the cell cycle control protein p21 in human monocyte-derived macrophages to contribute to SAMHD1 activation. We additionally present data that support another, potentially redox-dependent mechanism employed by SFN to contribute to SAMHD1 activation through reduced phosphorylation. This work establishes the use of exogenous Nrf2 mobilizers as a novel way to study virus restriction by SAMHD1 and highlights the Nrf2 pathway as a potential target for the therapeutic control of SAMHD1 cellular and antiviral functions. IMPORTANCE Here, we show, for the first time, that the treatment of macrophages with Nrf2 mobilizers, known activators of antioxidant responses, increases the fraction of SAMHD1 without a regulatory phosphate at position 592. We demonstrate that this decreases infection of macrophages by HIV-1. Phosphorylated SAMHD1 is important for DNA repair, the suppression of LINE elements, the maintenance of HIV-1 in a latent state, and the prevention of excessive type I interferon responses, while unphosphorylated SAMHD1 blocks HIV infection. SAMHD1 impacts many viruses and is involved in various cancers, so knowledge of how it works and how it is regulated has broad implications for the development of therapeutics. Redox-modulating therapeutics are already in clinical use or under investigation for the treatment of many conditions. Thus, understanding the impact of redox modifiers on controlling SAMHD1 phosphorylation is important for many areas of research in microbiology and beyond.
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Affiliation(s)
- H. John Sharifi
- Albany College of Pharmacy and Health Sciences, Albany, New York, USA
| | - Dakota N. Paine
- Albany College of Pharmacy and Health Sciences, Albany, New York, USA
| | | | | | - Emilee Patterson
- Department of Immunology and Microbial Disease, Albany Medical College, Albany, New York, USA
| | - Carlos M. C. de Noronha
- Department of Immunology and Microbial Disease, Albany Medical College, Albany, New York, USA
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7
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Targeting SAMHD1: to overcome multiple anti-cancer drugs resistance in hematological malignancies. Genes Dis 2022. [DOI: 10.1016/j.gendis.2022.06.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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8
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Barrett B, Nguyen DH, Xu J, Guo K, Shetty S, Jones ST, Mickens KL, Shepard C, Roers A, Behrendt R, Wu L, Kim B, Santiago ML. SAMHD1 Promotes the Antiretroviral Adaptive Immune Response in Mice Exposed to Lipopolysaccharide. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2022; 208:444-453. [PMID: 34893529 DOI: 10.4049/jimmunol.2001389] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Accepted: 11/08/2021] [Indexed: 12/13/2022]
Abstract
SAMHD1 is a potent HIV-1 restriction factor that blocks reverse transcription in monocytes, dendritic cells and resting CD4+ T cells by decreasing intracellular dNTP pools. However, SAMHD1 may diminish innate immune sensing and Ag presentation, resulting in a weaker adaptive immune response. To date, the role of SAMHD1 on antiretroviral immunity remains unclear, as mouse SAMHD1 had no impact on murine retrovirus replication in prior in vivo studies. Here, we show that SAMHD1 significantly inhibits acute Friend retrovirus infection in mice. Pretreatment with LPS, a significant driver of inflammation during HIV-1 infection, further unmasked a role for SAMHD1 in influencing immune responses. LPS treatment in vivo doubled the intracellular dNTP levels in immune compartments of SAMHD1 knockout but not wild-type mice. SAMHD1 knockout mice exhibited higher plasma infectious viremia and proviral DNA loads than wild-type mice at 7 d postinfection (dpi), and proviral loads inversely correlated with a stronger CD8+ T cell response. SAMHD1 deficiency was also associated with weaker NK, CD4+ T and CD8+ T cell responses by 14 dpi and weaker neutralizing Ab responses by 28 dpi. Intriguingly, SAMHD1 influenced these cell-mediated immune (14 dpi) and neutralizing Ab (28 dpi) responses in male but not female mice. Our findings formally demonstrate SAMHD1 as an antiretroviral factor in vivo that could promote adaptive immune responses in a sex-dependent manner. The requirement for LPS to unravel the SAMHD1 immunological phenotype suggests that comorbidities associated with a "leaky" gut barrier may influence the antiviral function of SAMHD1 in vivo.
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Affiliation(s)
- BradleyS Barrett
- Department of Medicine, University of Colorado School of Medicine, Aurora, CO
| | - David H Nguyen
- Department of Medicine, University of Colorado School of Medicine, Aurora, CO
| | - Joella Xu
- Department of Pediatrics, School of Medicine, Emory University, Atlanta, GA
| | - Kejun Guo
- Department of Medicine, University of Colorado School of Medicine, Aurora, CO
| | - Shravida Shetty
- Department of Medicine, University of Colorado School of Medicine, Aurora, CO
| | - Sean T Jones
- Department of Medicine, University of Colorado School of Medicine, Aurora, CO.,Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, CO
| | - Kaylee L Mickens
- Department of Medicine, University of Colorado School of Medicine, Aurora, CO.,Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, CO
| | - Caitlin Shepard
- Department of Pediatrics, School of Medicine, Emory University, Atlanta, GA
| | - Axel Roers
- Institute for Immunology, Faculty of Medicine, Technical University Dresden, Dresden, Germany
| | - Rayk Behrendt
- Institute for Immunology, Faculty of Medicine, Technical University Dresden, Dresden, Germany
| | - Li Wu
- Department of Microbiology and Immunology, Carver College of Medicine, University of Iowa, Iowa City, IA; and
| | - Baek Kim
- Department of Pediatrics, School of Medicine, Emory University, Atlanta, GA.,Center for Drug Discovery, Children's Healthcare of Atlanta, Atlanta, GA
| | - Mario L Santiago
- Department of Medicine, University of Colorado School of Medicine, Aurora, CO; .,Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, CO
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Canino F, Moscetti L, Borghi V, Dominici M, Piacentini F. Palbociclib in a patient with HR+/HER2- advanced breast cancer and HIV1 infection: a case report. BREAST CANCER MANAGEMENT 2021. [DOI: 10.2217/bmt-2021-0006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The use of drugs that affect the cell cycle represents one of the common strategies for the control of some unrelated pathologies, such as chronic viral HIV infections or cancer. The authors report the case of a patient followed for a hormone receptor-positive (HR+)/HER2 negative (HER2-) advanced breast cancer, treated with hormone therapy and CDK 4/6 inhibitors, and a concomitant HIV infection under antiretroviral treatment. The authors consider the function of the sterile alpha motif and HD domain-containing protein-1 (SAMHD1) enzyme, its implications in the control of viral replication and the correlation between its activity and the mechanism of action of the CDK 4/6 inhibitor palbociclib.
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Affiliation(s)
- Fabio Canino
- Division of Oncology, Department of Oncology & Hematology, University Hospital of Modena, Modena, Italy
| | - Luca Moscetti
- Division of Oncology, Department of Oncology & Hematology, University Hospital of Modena, Modena, Italy
| | - Vanni Borghi
- Division of Infectious Diseases, Department of Specialized Medicine, University Hospital of Modena, Modena, Italy
| | - Massimo Dominici
- Division of Oncology, Department of Medical & Surgical Sciences for Children & Adults, University Hospital of Modena, Italy
| | - Federico Piacentini
- Division of Oncology, Department of Medical & Surgical Sciences for Children & Adults, University Hospital of Modena, Italy
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10
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Regulation of Viral Restriction by Post-Translational Modifications. Viruses 2021; 13:v13112197. [PMID: 34835003 PMCID: PMC8618861 DOI: 10.3390/v13112197] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Revised: 10/28/2021] [Accepted: 10/29/2021] [Indexed: 12/17/2022] Open
Abstract
Intrinsic immunity is orchestrated by a wide range of host cellular proteins called restriction factors. They have the capacity to interfere with viral replication, and most of them are tightly regulated by interferons (IFNs). In addition, their regulation through post-translational modifications (PTMs) constitutes a major mechanism to shape their action positively or negatively. Following viral infection, restriction factor modification can be decisive. Palmitoylation of IFITM3, SUMOylation of MxA, SAMHD1 and TRIM5α or glycosylation of BST2 are some of those PTMs required for their antiviral activity. Nonetheless, for their benefit and by manipulating the PTMs machinery, viruses have evolved sophisticated mechanisms to counteract restriction factors. Indeed, many viral proteins evade restriction activity by inducing their ubiquitination and subsequent degradation. Studies on PTMs and their substrates are essential for the understanding of the antiviral defense mechanisms and provide a global vision of all possible regulations of the immune response at a given time and under specific infection conditions. Our aim was to provide an overview of current knowledge regarding the role of PTMs on restriction factors with an emphasis on their impact on viral replication.
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11
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Martinat C, Cormier A, Tobaly-Tapiero J, Palmic N, Casartelli N, Mahboubi B, Coggins SA, Buchrieser J, Persaud M, Diaz-Griffero F, Espert L, Bossis G, Lesage P, Schwartz O, Kim B, Margottin-Goguet F, Saïb A, Zamborlini A. SUMOylation of SAMHD1 at Lysine 595 is required for HIV-1 restriction in non-cycling cells. Nat Commun 2021; 12:4582. [PMID: 34321470 PMCID: PMC8319325 DOI: 10.1038/s41467-021-24802-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2020] [Accepted: 07/05/2021] [Indexed: 02/06/2023] Open
Abstract
SAMHD1 is a cellular triphosphohydrolase (dNTPase) proposed to inhibit HIV-1 reverse transcription in non-cycling immune cells by limiting the supply of the dNTP substrates. Yet, phosphorylation of T592 downregulates SAMHD1 antiviral activity, but not its dNTPase function, implying that additional mechanisms contribute to viral restriction. Here, we show that SAMHD1 is SUMOylated on residue K595, a modification that relies on the presence of a proximal SUMO-interacting motif (SIM). Loss of K595 SUMOylation suppresses the restriction activity of SAMHD1, even in the context of the constitutively active phospho-ablative T592A mutant but has no impact on dNTP depletion. Conversely, the artificial fusion of SUMO2 to a non-SUMOylatable inactive SAMHD1 variant restores its antiviral function, a phenotype that is reversed by the phosphomimetic T592E mutation. Collectively, our observations clearly establish that lack of T592 phosphorylation cannot fully account for the restriction activity of SAMHD1. We find that SUMOylation of K595 is required to stimulate a dNTPase-independent antiviral activity in non-cycling immune cells, an effect that is antagonized by cyclin/CDK-dependent phosphorylation of T592 in cycling cells.
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Affiliation(s)
- Charlotte Martinat
- INSERM U944, CNRS UMR 7212, Genomes & Cell Biology of Disease Unit, Institut de Recherche Saint-Louis, Université de Paris, Hôpital Saint-Louis, Paris, France
| | - Arthur Cormier
- INSERM U944, CNRS UMR 7212, Genomes & Cell Biology of Disease Unit, Institut de Recherche Saint-Louis, Université de Paris, Hôpital Saint-Louis, Paris, France
| | - Joëlle Tobaly-Tapiero
- INSERM U944, CNRS UMR 7212, Genomes & Cell Biology of Disease Unit, Institut de Recherche Saint-Louis, Université de Paris, Hôpital Saint-Louis, Paris, France
| | - Noé Palmic
- INSERM U944, CNRS UMR 7212, Genomes & Cell Biology of Disease Unit, Institut de Recherche Saint-Louis, Université de Paris, Hôpital Saint-Louis, Paris, France
| | - Nicoletta Casartelli
- grid.428999.70000 0001 2353 6535Institut Pasteur, Virus and Immunity Unit, CNRS-UMR3569, Paris, France ,grid.511001.4Vaccine Research Institute, Créteil, France
| | - Bijan Mahboubi
- grid.189967.80000 0001 0941 6502Emory School of Medicine, Atlanta, USA
| | - Si’Ana A. Coggins
- grid.189967.80000 0001 0941 6502Emory School of Medicine, Atlanta, USA
| | - Julian Buchrieser
- grid.428999.70000 0001 2353 6535Institut Pasteur, Virus and Immunity Unit, CNRS-UMR3569, Paris, France ,grid.511001.4Vaccine Research Institute, Créteil, France ,grid.4991.50000 0004 1936 8948James Martin Stem Cell Facility, Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Mirjana Persaud
- grid.251993.50000000121791997Albert Einstein College of Medicine, Microbiology and Immunology, Bronx, NY USA
| | - Felipe Diaz-Griffero
- grid.251993.50000000121791997Albert Einstein College of Medicine, Microbiology and Immunology, Bronx, NY USA
| | - Lucile Espert
- grid.503217.2IRIM, University of Montpellier, UMR 9004 CNRS, Montpellier, France
| | - Guillaume Bossis
- grid.429192.50000 0004 0599 0285IGMM, Univ Montpellier, CNRS, Montpellier, France
| | - Pascale Lesage
- INSERM U944, CNRS UMR 7212, Genomes & Cell Biology of Disease Unit, Institut de Recherche Saint-Louis, Université de Paris, Hôpital Saint-Louis, Paris, France
| | - Olivier Schwartz
- grid.428999.70000 0001 2353 6535Institut Pasteur, Virus and Immunity Unit, CNRS-UMR3569, Paris, France ,grid.511001.4Vaccine Research Institute, Créteil, France
| | - Baek Kim
- grid.189967.80000 0001 0941 6502Emory School of Medicine, Atlanta, USA
| | | | - Ali Saïb
- INSERM U944, CNRS UMR 7212, Genomes & Cell Biology of Disease Unit, Institut de Recherche Saint-Louis, Université de Paris, Hôpital Saint-Louis, Paris, France
| | - Alessia Zamborlini
- INSERM U944, CNRS UMR 7212, Genomes & Cell Biology of Disease Unit, Institut de Recherche Saint-Louis, Université de Paris, Hôpital Saint-Louis, Paris, France ,grid.457334.2Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, France
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12
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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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13
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De Meo S, Dell'Oste V, Molfetta R, Tassinari V, Lotti LV, Vespa S, Pignoloni B, Covino DA, Fantuzzi L, Bona R, Zingoni A, Nardone I, Biolatti M, Coscia A, Paolini R, Benkirane M, Edfors F, Sandalova T, Achour A, Hiscott J, Landolfo S, Santoni A, Cerboni C. SAMHD1 phosphorylation and cytoplasmic relocalization after human cytomegalovirus infection limits its antiviral activity. PLoS Pathog 2020; 16:e1008855. [PMID: 32986788 PMCID: PMC7544099 DOI: 10.1371/journal.ppat.1008855] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Revised: 10/08/2020] [Accepted: 08/03/2020] [Indexed: 12/16/2022] Open
Abstract
SAMHD1 is a host restriction factor that functions to restrict both retroviruses and DNA viruses, based on its nuclear deoxynucleotide triphosphate (dNTP) hydrolase activity that limits availability of intracellular dNTP pools. In the present study, we demonstrate that SAMHD1 expression was increased following human cytomegalovirus (HCMV) infection, with only a modest effect on infectious virus production. SAMHD1 was rapidly phosphorylated at residue T592 after infection by cellular cyclin-dependent kinases, especially Cdk2, and by the viral kinase pUL97, resulting in a significant fraction of phosho-SAMHD1 being relocalized to the cytoplasm of infected fibroblasts, in association with viral particles and dense bodies. Thus, our findings indicate that HCMV-dependent SAMHD1 cytoplasmic delocalization and inactivation may represent a potential novel mechanism of HCMV evasion from host antiviral restriction activities.
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Affiliation(s)
- Simone De Meo
- Department of Molecular Medicine, "Sapienza" University of Rome, Rome, Italy
| | - Valentina Dell'Oste
- Department of Public Health and Pediatric Sciences, University of Turin, Turin, Italy
| | - Rosa Molfetta
- Department of Molecular Medicine, "Sapienza" University of Rome, Rome, Italy
| | - Valentina Tassinari
- Department of Molecular Medicine, "Sapienza" University of Rome, Rome, Italy
| | | | - Simone Vespa
- Laboratory of General Pathology, Center of Aging Science and Translational Medicine (CeSI-MeT) and Department of Medical, Oral and Biotechnological Sciences G. d'Annunzio University, Chieti, Italy
| | - Benedetta Pignoloni
- Department of Molecular Medicine, "Sapienza" University of Rome, Rome, Italy
| | | | - Laura Fantuzzi
- National Center for Global Health, Istituto Superiore di Sanità, Rome, Italy
| | - Roberta Bona
- National Center for Global Health, Istituto Superiore di Sanità, Rome, Italy
| | - Alessandra Zingoni
- Department of Molecular Medicine, "Sapienza" University of Rome, Rome, Italy
| | - Ilaria Nardone
- Department of Molecular Medicine, "Sapienza" University of Rome, Rome, Italy
| | - Matteo Biolatti
- Department of Public Health and Pediatric Sciences, University of Turin, Turin, Italy
| | - Alessandra Coscia
- Neonatal Unit, Department of Public Health and Pediatric Sciences, University of Turin, Turin, Italy
| | - Rossella Paolini
- Department of Molecular Medicine, "Sapienza" University of Rome, Rome, Italy
| | - Monsef Benkirane
- Institut de Génétique Humaine, Laboratoire de Virologie Moléculaire, CNRS-Université de Montpellier, Montpellier, France
| | - Fredrik Edfors
- Science for Life Laboratory, Department of Medicine Solna, Karolinska Institute, and Division of Infectious Diseases, Karolinska University Hospital, Stockholm, Sweden
| | - Tatyana Sandalova
- Science for Life Laboratory, Department of Medicine Solna, Karolinska Institute, and Division of Infectious Diseases, Karolinska University Hospital, Stockholm, Sweden
| | - Adnane Achour
- Science for Life Laboratory, Department of Medicine Solna, Karolinska Institute, and Division of Infectious Diseases, Karolinska University Hospital, Stockholm, Sweden
| | - John Hiscott
- Istituto Pasteur Italia-Cenci Bolognetti Foundation, Rome, Italy
| | - Santo Landolfo
- Department of Public Health and Pediatric Sciences, University of Turin, Turin, Italy
| | - Angela Santoni
- Department of Molecular Medicine, "Sapienza" University of Rome, Rome, Italy
- IRCCS, Neuromed, Pozzilli, Isernia, Italy
| | - Cristina Cerboni
- Department of Molecular Medicine, "Sapienza" University of Rome, Rome, Italy
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14
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Resop RS, Fromentin R, Newman D, Rigsby H, Dubrovsky L, Bukrinsky M, Chomont N, Bosque A. Fingolimod inhibits multiple stages of the HIV-1 life cycle. PLoS Pathog 2020; 16:e1008679. [PMID: 32790802 PMCID: PMC7425850 DOI: 10.1371/journal.ppat.1008679] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Accepted: 06/03/2020] [Indexed: 02/07/2023] Open
Abstract
Antiretroviral drugs that target various stages of the Human Immunodeficiency Virus (HIV) life cycle have been effective in curbing the AIDS epidemic. However, drug resistance, off-target effects of antiretroviral therapy (ART), and varying efficacy in prevention underscore the need to develop novel and alternative therapeutics. In this study, we investigated whether targeting the signaling molecule Sphingosine-1-phosphate (S1P) would inhibit HIV-1 infection and generation of the latent reservoir in primary CD4 T cells. We show that FTY720 (Fingolimod), an FDA-approved functional antagonist of S1P receptors, blocks cell-free and cell-to-cell transmission of HIV and consequently reduces detectable latent virus. Mechanistically, FTY720 impacts the HIV-1 life cycle at two levels. Firstly, FTY720 reduces the surface density of CD4, thereby inhibiting viral binding and fusion. Secondly, FTY720 decreases the phosphorylation of the innate HIV restriction factor SAMHD1 which is associated with reduced levels of total and integrated HIV, while reducing the expression of Cyclin D3. In conclusion, targeting the S1P pathway with FTY720 could be a novel strategy to inhibit HIV replication and reduce the seeding of the latent reservoir.
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Affiliation(s)
- Rachel S. Resop
- Department of Microbiology, Immunology and Tropical Medicine, The George Washington University, Washington, D.C., United States of America
| | - Rémi Fromentin
- Centre de recherche du CHUM and Department of microbiology, infectiology and immunology, Université de Montréal, Montreal, Canada
| | - Daniel Newman
- Department of Microbiology, Immunology and Tropical Medicine, The George Washington University, Washington, D.C., United States of America
| | - Hawley Rigsby
- Centre de recherche du CHUM and Department of microbiology, infectiology and immunology, Université de Montréal, Montreal, Canada
| | - Larisa Dubrovsky
- Department of Microbiology, Immunology and Tropical Medicine, The George Washington University, Washington, D.C., United States of America
| | - Michael Bukrinsky
- Department of Microbiology, Immunology and Tropical Medicine, The George Washington University, Washington, D.C., United States of America
| | - Nicolas Chomont
- Centre de recherche du CHUM and Department of microbiology, infectiology and immunology, Université de Montréal, Montreal, Canada
| | - Alberto Bosque
- Department of Microbiology, Immunology and Tropical Medicine, The George Washington University, Washington, D.C., United States of America
- * E-mail:
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15
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Hyeon S, Lee MK, Kim YE, Lee GM, Ahn JH. Degradation of SAMHD1 Restriction Factor Through Cullin-Ring E3 Ligase Complexes During Human Cytomegalovirus Infection. Front Cell Infect Microbiol 2020; 10:391. [PMID: 32850489 PMCID: PMC7406573 DOI: 10.3389/fcimb.2020.00391] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Accepted: 06/25/2020] [Indexed: 12/15/2022] Open
Abstract
Sterile alpha motif (SAM) and histidine-aspartate (HD) domain-containing protein 1 (SAMHD1) acts as a restriction factor for several RNA and DNA viruses by limiting the intracellular pool of deoxynucleoside triphosphates. Here, we investigated the regulation of SAMHD1 expression during human cytomegalovirus (HCMV) infection. SAMHD1 knockdown using shRNA increased the activity of the viral UL99 late gene promoter in human fibroblasts by 7- to 9-fold, confirming its anti-HCMV activity. We also found that the level of SAMHD1 was initially increased by HCMV infection but decreased partly at the protein level at late stages of infection. SAMHD1 loss was not observed with UV-inactivated virus and required viral DNA replication. This reduction of SAMHD1 was effectively blocked by MLN4924, an inhibitor of the Cullin-RING-E3 ligase (CRL) complexes, but not by bafilomycin A1, an inhibitor of vacuolar-type H+-ATPase. Indirect immunofluorescence assays further supported the CRL-mediated SAMHD1 loss at late stages of virus infection. Knockdown of CUL2 and to a lesser extent CUL1 using siRNA stabilized SAMHD1 in normal fibroblasts and inhibited SAMHD1 loss during virus infection. Altogether, our results demonstrate that SAMHD1 inhibits the growth of HCMV, but HCMV causes degradation of SAMHD1 at late stages of viral infection through the CRL complexes.
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Affiliation(s)
- Seokhwan Hyeon
- Department of Microbiology, Sungkyunkwan University School of Medicine, Suwon-si, South Korea
| | - Myoung Kyu Lee
- Department of Microbiology, Sungkyunkwan University School of Medicine, Suwon-si, South Korea
| | - Young-Eui Kim
- Department of Microbiology, Sungkyunkwan University School of Medicine, Suwon-si, South Korea
| | - Gwang Myeong Lee
- Department of Microbiology, Sungkyunkwan University School of Medicine, Suwon-si, South Korea
| | - Jin-Hyun Ahn
- Department of Microbiology, Sungkyunkwan University School of Medicine, Suwon-si, South Korea
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16
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Khan N, Chen X, Geiger JD. Role of Divalent Cations in HIV-1 Replication and Pathogenicity. Viruses 2020; 12:E471. [PMID: 32326317 PMCID: PMC7232465 DOI: 10.3390/v12040471] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 04/09/2020] [Accepted: 04/18/2020] [Indexed: 12/22/2022] Open
Abstract
Divalent cations are essential for life and are fundamentally important coordinators of cellular metabolism, cell growth, host-pathogen interactions, and cell death. Specifically, for human immunodeficiency virus type-1 (HIV-1), divalent cations are required for interactions between viral and host factors that govern HIV-1 replication and pathogenicity. Homeostatic regulation of divalent cations' levels and actions appear to change as HIV-1 infection progresses and as changes occur between HIV-1 and the host. In people living with HIV-1, dietary supplementation with divalent cations may increase HIV-1 replication, whereas cation chelation may suppress HIV-1 replication and decrease disease progression. Here, we review literature on the roles of zinc (Zn2+), iron (Fe2+), manganese (Mn2+), magnesium (Mg2+), selenium (Se2+), and copper (Cu2+) in HIV-1 replication and pathogenicity, as well as evidence that divalent cation levels and actions may be targeted therapeutically in people living with HIV-1.
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Affiliation(s)
| | | | - Jonathan D. Geiger
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND 58203, USA; (N.K.); (X.C.)
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17
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SAMHD1 Functions and Human Diseases. Viruses 2020; 12:v12040382. [PMID: 32244340 PMCID: PMC7232136 DOI: 10.3390/v12040382] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Revised: 03/27/2020] [Accepted: 03/28/2020] [Indexed: 12/12/2022] Open
Abstract
Deoxynucleoside triphosphate (dNTP) molecules are essential for the replication and maintenance of genomic information in both cells and a variety of viral pathogens. While the process of dNTP biosynthesis by cellular enzymes, such as ribonucleotide reductase (RNR) and thymidine kinase (TK), has been extensively investigated, a negative regulatory mechanism of dNTP pools was recently found to involve sterile alpha motif (SAM) domain and histidine-aspartate (HD) domain-containing protein 1, SAMHD1. When active, dNTP triphosphohydrolase activity of SAMHD1 degrades dNTPs into their 2'-deoxynucleoside (dN) and triphosphate subparts, steadily depleting intercellular dNTP pools. The differential expression levels and activation states of SAMHD1 in various cell types contributes to unique dNTP pools that either aid (i.e., dividing T cells) or restrict (i.e., nondividing macrophages) viral replication that consumes cellular dNTPs. Genetic mutations in SAMHD1 induce a rare inflammatory encephalopathy called Aicardi-Goutières syndrome (AGS), which phenotypically resembles viral infection. Recent publications have identified diverse roles for SAMHD1 in double-stranded break repair, genome stability, and the replication stress response through interferon signaling. Finally, a series of SAMHD1 mutations were also reported in various cancer cell types while why SAMHD1 is mutated in these cancer cells remains to investigated. Here, we reviewed a series of studies that have begun illuminating the highly diverse roles of SAMHD1 in virology, immunology, and cancer biology.
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18
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Zhang Z, Zheng L, Yu Y, Wu J, Yang F, Xu Y, Guo Q, Wu X, Cao S, Cao L, Song X. Involvement of SAMHD1 in dNTP homeostasis and the maintenance of genomic integrity and oncotherapy (Review). Int J Oncol 2020; 56:879-888. [PMID: 32319570 DOI: 10.3892/ijo.2020.4988] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Accepted: 02/07/2020] [Indexed: 11/06/2022] Open
Abstract
Sterile alpha motif and histidine/aspartic acid domain‑containing protein 1 (SAMHD1), the only deoxynucleotide triphosphate (dNTP) hydrolase in eukaryotes, plays a crucial role in regulating the dynamic balance and ratio of cellular dNTP pools. Furthermore, SAMHD1 has been reported to be involved in the pathological process of several diseases. Homozygous SAMHD1 mutations have been identified in immune system disorders, such as autoimmune disease Aicardi‑Goutières syndrome (AGS), whose primary pathogenesis is associated with the abnormal accumulation and disproportion of dNTPs. SAMHD1 is also considered to be an intrinsic virus‑restriction factor by suppressing the viral infection process, including reverse transcription, replication, packaging and transmission. In addition, SAMHD1 has been shown to promote genome integrity during homologous recombination following DNA damage, thus being considered a promising candidate for oncotherapy applications. The present review summarizes the molecular mechanisms of SAMHD1 regarding the regulation of dNTP homeostasis and DNA damage response. Additionally, its potential effects on tumorigenesis and oncotherapy are reported.
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Affiliation(s)
- Zhou Zhang
- College of Basic Medical Science, Institute of Translational Medicine, China Medical University, Shenyang, Liaoning 110122, P.R. China
| | - Lixia Zheng
- College of Basic Medical Science, Institute of Translational Medicine, China Medical University, Shenyang, Liaoning 110122, P.R. China
| | - Yang Yu
- College of Basic Medical Science, Institute of Translational Medicine, China Medical University, Shenyang, Liaoning 110122, P.R. China
| | - Jinying Wu
- College of Basic Medical Science, Institute of Translational Medicine, China Medical University, Shenyang, Liaoning 110122, P.R. China
| | - Fan Yang
- College of Basic Medical Science, Institute of Translational Medicine, China Medical University, Shenyang, Liaoning 110122, P.R. China
| | - Yingxi Xu
- College of Basic Medical Science, Institute of Translational Medicine, China Medical University, Shenyang, Liaoning 110122, P.R. China
| | - Qiqiang Guo
- College of Basic Medical Science, Institute of Translational Medicine, China Medical University, Shenyang, Liaoning 110122, P.R. China
| | - Xuan Wu
- College of Basic Medical Science, Institute of Translational Medicine, China Medical University, Shenyang, Liaoning 110122, P.R. China
| | - Sunrun Cao
- College of Basic Medical Science, Institute of Translational Medicine, China Medical University, Shenyang, Liaoning 110122, P.R. China
| | - Liu Cao
- College of Basic Medical Science, Institute of Translational Medicine, China Medical University, Shenyang, Liaoning 110122, P.R. China
| | - Xiaoyu Song
- College of Basic Medical Science, Institute of Translational Medicine, China Medical University, Shenyang, Liaoning 110122, P.R. China
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19
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Qin Z, Bonifati S, St Gelais C, Li TW, Kim SH, Antonucci JM, Mahboubi B, Yount JS, Xiong Y, Kim B, Wu L. The dNTPase activity of SAMHD1 is important for its suppression of innate immune responses in differentiated monocytic cells. J Biol Chem 2020; 295:1575-1586. [PMID: 31914403 PMCID: PMC7008377 DOI: 10.1074/jbc.ra119.010360] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Revised: 12/22/2019] [Indexed: 12/18/2022] Open
Abstract
Sterile alpha motif and HD domain-containing protein 1 (SAMHD1) is a deoxynucleoside triphosphohydrolase (dNTPase) with a nuclear localization signal (NLS). SAMHD1 suppresses innate immune responses to viral infection and inflammatory stimuli by inhibiting the NF-κB and type I interferon (IFN-I) pathways. However, whether the dNTPase activity and nuclear localization of SAMHD1 are required for its suppression of innate immunity remains unknown. Here, we report that the dNTPase activity, but not nuclear localization of SAMHD1, is important for its suppression of innate immune responses in differentiated monocytic cells. We generated monocytic U937 cell lines stably expressing WT SAMHD1 or mutated variants defective in dNTPase activity (HD/RN) or nuclear localization (mNLS). WT SAMHD1 in differentiated U937 cells significantly inhibited lipopolysaccharide-induced expression of tumor necrosis factor α (TNF-α) and interleukin-6 (IL-6) mRNAs, as well as IFN-α, IFN-β, and TNF-α mRNA levels induced by Sendai virus infection. In contrast, the HD/RN mutant did not exhibit this inhibition in either U937 or THP-1 cells, indicating that the dNTPase activity of SAMHD1 is important for suppressing NF-κB activation. Of note, in lipopolysaccharide-treated or Sendai virus-infected U937 or THP-1 cells, the mNLS variant reduced TNF-α or IFN-β mRNA expression to a similar extent as did WT SAMHD1, suggesting that SAMHD1-mediated inhibition of innate immune responses is independent of SAMHD1's nuclear localization. Moreover, WT and mutant SAMHD1 similarly interacted with key proteins in NF-κB and IFN-I pathways in cells. This study further defines the role and mechanisms of SAMHD1 in suppressing innate immunity.
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Affiliation(s)
- Zhihua Qin
- Center for Retrovirus Research, Department of Veterinary Biosciences, The Ohio State University, Columbus, Ohio 43210; Department of Microbiology and Immunology, Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242
| | - Serena Bonifati
- Center for Retrovirus Research, Department of Veterinary Biosciences, The Ohio State University, Columbus, Ohio 43210
| | - Corine St Gelais
- Center for Retrovirus Research, Department of Veterinary Biosciences, The Ohio State University, Columbus, Ohio 43210
| | - Tai-Wei Li
- Center for Retrovirus Research, Department of Veterinary Biosciences, The Ohio State University, Columbus, Ohio 43210
| | - Sun-Hee Kim
- Center for Retrovirus Research, Department of Veterinary Biosciences, The Ohio State University, Columbus, Ohio 43210
| | - Jenna M Antonucci
- Center for Retrovirus Research, Department of Veterinary Biosciences, The Ohio State University, Columbus, Ohio 43210
| | - Bijan Mahboubi
- Center for Drug Discovery, Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia 30322
| | - Jacob S Yount
- Department of Microbial Infection and Immunity, Infectious Diseases Institute, The Ohio State University, Columbus, Ohio 43210
| | - Yong Xiong
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520
| | - Baek Kim
- Center for Drug Discovery, Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia 30322
| | - Li Wu
- Center for Retrovirus Research, Department of Veterinary Biosciences, The Ohio State University, Columbus, Ohio 43210; Department of Microbiology and Immunology, Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242; Department of Microbial Infection and Immunity, Infectious Diseases Institute, The Ohio State University, Columbus, Ohio 43210.
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20
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Martín-Moreno A, Muñoz-Fernández MA. Dendritic Cells, the Double Agent in the War Against HIV-1. Front Immunol 2019; 10:2485. [PMID: 31708924 PMCID: PMC6820366 DOI: 10.3389/fimmu.2019.02485] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Accepted: 10/04/2019] [Indexed: 12/19/2022] Open
Abstract
Human Immunodeficiency Virus (HIV) infects cells from the immune system and has thus developed tools to circumvent the host immunity and use it in its advance. Dendritic cells (DCs) are the first immune cells to encounter the HIV, and being the main antigen (Ag) presenting cells, they link the innate and the adaptive immune responses. While DCs work to promote an efficient immune response and halt the infection, HIV-1 has ways to take advantage of their role and uses DCs to gain faster and more efficient access to CD4+ T cells. Due to their ability to activate a specific immune response, DCs are promising candidates to achieve the functional cure of HIV-1 infection, but knowing the molecular partakers that determine the relationship between virus and cell is the key for the rational and successful design of a DC-based therapy. In this review, we summarize the current state of knowledge on how both DC subsets (myeloid and plasmacytoid DCs) act in presence of HIV-1, and focus on different pathways that the virus can take after binding to DC. First, we explore the consequences of HIV-1 recognition by each receptor on DCs, including CD4 and DC-SIGN. Second, we look at cellular mechanisms that prevent productive infection and weapons that turn cellular defense into a Trojan horse that hides the virus all the way to T cell. Finally, we discuss the possible outcomes of DC-T cell contact.
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Affiliation(s)
- Alba Martín-Moreno
- Sección de Inmunología, Laboratorio InmunoBiología Molecular, Hospital General Universitario Gregorio Marañón (HGUGM), Madrid, Spain.,Instituto Investigación Sanitaria Gregorio Marañón (IiSGM), Madrid, Spain
| | - Mª Angeles Muñoz-Fernández
- Sección de Inmunología, Laboratorio InmunoBiología Molecular, Hospital General Universitario Gregorio Marañón (HGUGM), Madrid, Spain.,Instituto Investigación Sanitaria Gregorio Marañón (IiSGM), Madrid, Spain.,Spanish HIV-HGM BioBank, Madrid, Spain.,Networking Research Center on Bioengineering, Biomaterials and Nanomedicine (CIBER BBN), Madrid, Spain
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21
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Human cytomegalovirus overcomes SAMHD1 restriction in macrophages via pUL97. Nat Microbiol 2019; 4:2260-2272. [PMID: 31548682 DOI: 10.1038/s41564-019-0557-8] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Accepted: 08/09/2019] [Indexed: 12/30/2022]
Abstract
The host restriction factor sterile alpha motif and histidine-aspartate domain-containing protein 1 (SAMHD1) is an important component of the innate immune system. By regulating the intracellular nucleotide pool, SAMHD1 influences cell division and restricts the replication of viruses that depend on high nucleotide concentrations. Human cytomegalovirus (HCMV) is a pathogenic virus with a tropism for non-dividing myeloid cells, in which SAMHD1 is catalytically active. Here we investigate how HCMV achieves efficient propagation in these cells despite the SAMHD1-mediated dNTP depletion. Our analysis reveals that SAMHD1 has the capability to suppress HCMV replication. However, HCMV has evolved potent countermeasures to circumvent this block. HCMV interferes with SAMHD1 steady-state expression and actively induces SAMHD1 phosphorylation using the viral kinase pUL97 and by hijacking cellular kinases. These actions convert SAMHD1 to its inactive phosphorylated form. This mechanism of SAMHD1 inactivation by phosphorylation might also be used by other viruses to overcome intrinsic immunity.
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22
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Wing PA, Davenne T, Wettengel J, Lai AG, Zhuang X, Chakraborty A, D'Arienzo V, Kramer C, Ko C, Harris JM, Schreiner S, Higgs M, Roessler S, Parish JL, Protzer U, Balfe P, Rehwinkel J, McKeating JA. A dual role for SAMHD1 in regulating HBV cccDNA and RT-dependent particle genesis. Life Sci Alliance 2019; 2:e201900355. [PMID: 30918010 PMCID: PMC6438393 DOI: 10.26508/lsa.201900355] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Revised: 03/15/2019] [Accepted: 03/18/2019] [Indexed: 02/06/2023] Open
Abstract
Chronic hepatitis B is one of the world's unconquered diseases with more than 240 million infected subjects at risk of developing liver disease and hepatocellular carcinoma. Hepatitis B virus reverse transcribes pre-genomic RNA to relaxed circular DNA (rcDNA) that comprises the infectious particle. To establish infection of a naïve target cell, the newly imported rcDNA is repaired by host enzymes to generate covalently closed circular DNA (cccDNA), which forms the transcriptional template for viral replication. SAMHD1 is a component of the innate immune system that regulates deoxyribonucleoside triphosphate levels required for host and viral DNA synthesis. Here, we show a positive role for SAMHD1 in regulating cccDNA formation, where KO of SAMHD1 significantly reduces cccDNA levels that was reversed by expressing wild-type but not a mutated SAMHD1 lacking the nuclear localization signal. The limited pool of cccDNA in infected Samhd1 KO cells is transcriptionally active, and we observed a 10-fold increase in newly synthesized rcDNA-containing particles, demonstrating a dual role for SAMHD1 to both facilitate cccDNA genesis and to restrict reverse transcriptase-dependent particle genesis.
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Affiliation(s)
- Peter Ac Wing
- Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Tamara Davenne
- Medical Research Council Human Immunology Unit, Medical Research Council Weatherall Institute of Molecular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Jochen Wettengel
- Institute of Virology, Technische Universität München/Helmholtz Zentrum München, Munich, Germany
| | - Alvina G Lai
- Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Xiaodong Zhuang
- Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Anindita Chakraborty
- Institute of Virology, Technische Universität München/Helmholtz Zentrum München, Munich, Germany
| | | | - Catharina Kramer
- Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Chunkyu Ko
- Institute of Virology, Technische Universität München/Helmholtz Zentrum München, Munich, Germany
| | - James M Harris
- Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Sabrina Schreiner
- Institute of Virology, Technische Universität München/Helmholtz Zentrum München, Munich, Germany
- German Center for Infection Research (DZIF), Munich Partner Site, Munich, Germany
| | - Martin Higgs
- Institutes of Cancer and Genomic Sciences and Immunity and Immunotherapy, College of Medical and Dental Sciences, University of Birmingham, UK
| | - Stephanie Roessler
- Institute of Pathology, University Hospital Heidelberg, Heidelberg, Germany
| | - Joanna L Parish
- Institutes of Cancer and Genomic Sciences and Immunity and Immunotherapy, College of Medical and Dental Sciences, University of Birmingham, UK
| | - Ulrike Protzer
- Institute of Virology, Technische Universität München/Helmholtz Zentrum München, Munich, Germany
- German Center for Infection Research (DZIF), Munich Partner Site, Munich, Germany
| | - Peter Balfe
- Institutes of Cancer and Genomic Sciences and Immunity and Immunotherapy, College of Medical and Dental Sciences, University of Birmingham, UK
| | - Jan Rehwinkel
- Medical Research Council Human Immunology Unit, Medical Research Council Weatherall Institute of Molecular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Jane A McKeating
- Nuffield Department of Medicine, University of Oxford, Oxford, UK
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23
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Buffone C, Kutzner J, Opp S, Martinez-Lopez A, Selyutina A, Coggings SA, Studdard LR, Ding L, Kim B, Spearman P, Schaller T, Diaz-Griffero F. The ability of SAMHD1 to block HIV-1 but not SIV requires expression of MxB. Virology 2019; 531:260-268. [PMID: 30959264 DOI: 10.1016/j.virol.2019.03.018] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Revised: 03/25/2019] [Accepted: 03/26/2019] [Indexed: 12/20/2022]
Abstract
SAMHD1 is a human restriction factor known to prevent infection of macrophages, resting CD4+ T cells, and dendritic cells by HIV-1. To test the contribution of MxB to the ability of SAMHD1 to block HIV-1 infection, we created human THP-1 cell lines that were knocked out for expression of MxB, SAMHD1, or both. Interestingly, MxB depletion renders SAMHD1 ineffective against HIV-1 but not SIVmac. We observed similar results in human primary macrophages that were knockdown for the expression of MxB. To understand how MxB assists SAMHD1 restriction of HIV-1, we examined direct interaction between SAMHD1 and MxB in pull-down experiments. In addition, we investigated several properties of SAMHD1 in the absence of MxB expression, including subcellular localization, phosphorylation of the SAMHD1 residue T592, and dNTPs levels. These experiments showed that SAMHD1 restriction of HIV-1 requires expression of MxB.
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Affiliation(s)
- Cindy Buffone
- Albert Einstein College of Medicine, Microbiology and Immunology, Bronx, NY, 10461, USA
| | - Juliane Kutzner
- University Hospital Heidelberg, Department of Infectious Diseases, Heidelberg, 69120, Germany
| | - Silvana Opp
- Albert Einstein College of Medicine, Microbiology and Immunology, Bronx, NY, 10461, USA
| | - Alicia Martinez-Lopez
- Albert Einstein College of Medicine, Microbiology and Immunology, Bronx, NY, 10461, USA
| | - Anastasia Selyutina
- Albert Einstein College of Medicine, Microbiology and Immunology, Bronx, NY, 10461, USA
| | | | | | - Lingmei Ding
- Cincinnati Children's Hospital, Infectious Diseases, Cincinnati, OH, 45229, USA
| | - Baek Kim
- Emory University, Pediatrics, Atlanta, 30322, Georgia
| | - Paul Spearman
- Cincinnati Children's Hospital, Infectious Diseases, Cincinnati, OH, 45229, USA
| | - Torsten Schaller
- University Hospital Heidelberg, Department of Infectious Diseases, Heidelberg, 69120, Germany
| | - Felipe Diaz-Griffero
- Albert Einstein College of Medicine, Microbiology and Immunology, Bronx, NY, 10461, USA.
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24
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The Polar Region of the HIV-1 Envelope Protein Determines Viral Fusion and Infectivity by Stabilizing the gp120-gp41 Association. J Virol 2019; 93:JVI.02128-18. [PMID: 30651369 DOI: 10.1128/jvi.02128-18] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Accepted: 01/12/2019] [Indexed: 02/06/2023] Open
Abstract
HIV-1 enters cells through binding between viral envelope glycoprotein (Env) and cellular receptors to initiate virus and cell fusion. HIV-1 Env precursor (gp160) is cleaved into two units noncovalently bound to form a trimer on virions, including a surface unit (gp120) and a transmembrane unit (gp41) responsible for virus binding and membrane fusion, respectively. The polar region (PR) at the N terminus of gp41 comprises 17 residues, including 7 polar amino acids. Previous studies suggested that the PR contributes to HIV-1 membrane fusion and infectivity; however, the precise role of the PR in Env-mediated viral entry and the underlying mechanisms remain unknown. Here, we show that the PR is critical for HIV-1 fusion and infectivity by stabilizing Env trimers. Through analyzing the PR sequences of 57,645 HIV-1 isolates, we performed targeted mutagenesis and functional studies of three highly conserved polar residues in the PR (S532P, T534A, and T536A) which have not been characterized previously. We found that single or combined mutations of these three residues abolished or significantly decreased HIV-1 infectivity without affecting viral production. These PR mutations abolished or significantly reduced HIV-1 fusion with target cells and also Env-mediated cell-cell fusion. Three PR mutations containing S532P substantially reduced gp120 and gp41 association, Env trimer stability, and increased gp120 shedding. Furthermore, S532A mutation significantly reduced HIV-1 infectivity and fusogenicity but not Env expression and cleavage. Our findings suggest that the PR of gp41, particularly the key residue S532, is structurally essential for maintaining HIV-1 Env trimer, viral fusogenicity, and infectivity.IMPORTANCE Although extensive studies of the transmembrane unit (gp41) of HIV-1 Env have led to a fusion inhibitor clinically used to block viral entry, the functions of different domains of gp41 in HIV-1 fusion and infectivity are not fully elucidated. The polar region (PR) of gp41 has been proposed to participate in HIV-1 membrane fusion in biochemical analyses, but its role in viral entry and infectivity remain unclear. In our effort to characterize three nucleotide mutations of an HIV-1 RNA element that partially overlaps the PR coding sequence, we identified a novel function of the PR that determines viral fusion and infectivity. We further demonstrated the structural and functional impact of six PR mutations on HIV-1 Env stability, viral fusion, and infectivity. Our findings reveal the previously unappreciated function of the PR and the underlying mechanisms, highlighting the important role of the PR in regulating HIV-1 fusion and infectivity.
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25
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Tirumuru N, Wu L. HIV-1 envelope proteins up-regulate N6-methyladenosine levels of cellular RNA independently of viral replication. J Biol Chem 2019; 294:3249-3260. [PMID: 30617182 PMCID: PMC6398121 DOI: 10.1074/jbc.ra118.005608] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 01/04/2019] [Indexed: 01/09/2023] Open
Abstract
N6-methyladenosine (m6A) modification of HIV-1 RNA regulates viral replication and protein expression. The m6A modification is regulated by two groups of cellular proteins named writers and erasers that add or remove m6A, respectively. HIV-1 infection of CD4+ T-cells increases m6A levels of cellular mRNA, but the underlying mechanism is unknown. Here, we show that HIV-1 infection of CD4+ primary T-cells or Jurkat cells significantly increases m6A levels of cellular RNA independently of viral replication. Compared with HIV-1-infected CD4+ T-cells, similar m6A up-regulation was detected in total RNA from HIV-1-infected cells treated with a reverse-transcriptase inhibitor or with heat-inactivated HIV-1. Compared with mock controls, significantly increased m6A levels were detected in total RNA from Jurkat cells infected by single-cycle HIV-1 pseudotyped with an HIV-1 envelope (Env) glycoprotein, but not with vesicular stomatitis virus glycoprotein G (VSV-G). Overexpression of HIV-1 Env in HEK293T cells did not affect m6A levels of cellular RNA, suggesting that de novo synthesis of Env is not required for m6A up-regulation. Interestingly, treatment of Jurkat cells with recombinant gp120 of HIV-1 Env significantly increased m6A levels of cellular RNA, which was reduced by a gp120-neutralizing antibody. Preincubation of Jurkat cells with a CD4 receptor-neutralizing antibody blocked HIV-1-induced up-regulation of m6A levels in cellular RNA. Moreover, HIV-1 infection or gp120 treatment did not alter the protein expression of m6A writers and erasers in cells. Our findings suggest that HIV-1 gp120 binding to the CD4 receptor is required for m6A up-regulation in cells.
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Affiliation(s)
- Nagaraja Tirumuru
- From the Center for Retrovirus Research, Department of Veterinary Biosciences and
- the Center for RNA Biology, Ohio State University, Columbus, Ohio 43210
| | - Li Wu
- From the Center for Retrovirus Research, Department of Veterinary Biosciences and
- the Center for RNA Biology, Ohio State University, Columbus, Ohio 43210
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26
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Kodigepalli KM, Li M, Bonifati S, Panfil AR, Green PL, Liu SL, Wu L. SAMHD1 inhibits epithelial cell transformation in vitro and affects leukemia development in xenograft mice. Cell Cycle 2018; 17:2564-2576. [PMID: 30474474 DOI: 10.1080/15384101.2018.1550955] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Sterile alpha motif and HD domain-containing protein 1 (SAMHD1) is a mammalian dNTP hydrolase (dNTPase) and functions as a negative regulator in the efficacy of cytarabine treatment of acute myeloid leukemia (AML). We have reported that SAMHD1 knockout (KO) increased the activity of phosphoinositide 3-kinase (PI3K) in AML-derived THP-1 cells and attenuated their ability to form subcutaneous tumors in xenografted immunodeficient mice. However, the functional significance of SAMHD1 in controlling AML leukemogenesis remains unclear. Previous studies show that in vitro transformation of Madin-Darby canine kidney (MDCK) epithelial cells by the Jaagsiekte sheep retrovirus (JSRV) envelope protein requires activation of the PI3K/Akt oncogenic signaling pathway. Using this cell transformation model, we demonstrated that ectopic expression of wild-type human SAMHD1 or a dNTPase-defective SAMHD1 mutant (HD/AA) significantly inhibited MDCK cell transformation, but did not affect cell proliferation. To visualize and quantify THP-1 cell growth and metastasis in xenografted immunodeficient mice, we generated luciferase-expressing stable SAMHD1 KO THP-1 cells and control THP-1 cells, which were injected intravenously into immunodeficient mice. Bioluminescence imaging and quantification analysis of xenografted mice revealed that SAMHD1 KO cell-derived tumors had similar growth and metastatic potential compared with control cells at 35 days post-injection. However, mice xenografted with SAMHD1 KO cells showed greater survival compared with mice injected with control cells. Our data suggest that exogenous SAMHD1 expression suppresses in vitro cell transformation independently of its dNTPase activity, and that endogenous SAMHD1 affects AML tumorigenicity and disease progression in vivo.
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Affiliation(s)
- Karthik M Kodigepalli
- a Center for Retrovirus Research, Department of Veterinary Biosciences , The Ohio State University , Columbus , OH , USA
| | - Minghua Li
- a Center for Retrovirus Research, Department of Veterinary Biosciences , The Ohio State University , Columbus , OH , USA
| | - Serena Bonifati
- a Center for Retrovirus Research, Department of Veterinary Biosciences , The Ohio State University , Columbus , OH , USA
| | - Amanda R Panfil
- a Center for Retrovirus Research, Department of Veterinary Biosciences , The Ohio State University , Columbus , OH , USA
| | - Patrick L Green
- a Center for Retrovirus Research, Department of Veterinary Biosciences , The Ohio State University , Columbus , OH , USA.,b Department of Cancer Biology and Genetics , The Ohio State University , Columbus , OH , USA.,c Comprehensive Cancer Center, The Ohio State University , Columbus , OH , USA
| | - Shan-Lu Liu
- a Center for Retrovirus Research, Department of Veterinary Biosciences , The Ohio State University , Columbus , OH , USA.,d Department of Microbial Infection and Immunity , The Ohio State University , Columbus , OH , USA
| | - Li Wu
- a Center for Retrovirus Research, Department of Veterinary Biosciences , The Ohio State University , Columbus , OH , USA.,c Comprehensive Cancer Center, The Ohio State University , Columbus , OH , USA.,d Department of Microbial Infection and Immunity , The Ohio State University , Columbus , OH , USA
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27
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Chen S, Bonifati S, Qin Z, St Gelais C, Wu L. SAMHD1 Suppression of Antiviral Immune Responses. Trends Microbiol 2018; 27:254-267. [PMID: 30336972 DOI: 10.1016/j.tim.2018.09.009] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Revised: 09/17/2018] [Accepted: 09/26/2018] [Indexed: 12/18/2022]
Abstract
SAMHD1 is a host triphosphohydrolase that degrades intracellular deoxynucleoside triphosphates (dNTPs) to a lower level that restricts viral DNA synthesis, and thus prevents replication of diverse viruses in nondividing cells. Recent progress indicates that SAMHD1 negatively regulates antiviral innate immune responses and inflammation through interacting with various key proteins in immune signaling and DNA damage-repair pathways. SAMHD1 can also modulate antibody production in adaptive immune responses. In this review, we summarize how SAMHD1 regulates antiviral immune responses through distinct mechanisms, and discuss the implications of these new functions of SAMHD1. Furthermore, we propose important new questions and future directions that can advance functional and mechanistic studies of SAMHD1-mediated immune regulation during viral infections.
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Affiliation(s)
- Shuliang Chen
- School of Basic Medical Sciences, Wuhan University, Wuhan, 430071, PR China; Center for Retrovirus Research, Department of Veterinary Biosciences, The Ohio State University, Columbus, OH 43210, USA
| | - Serena Bonifati
- Center for Retrovirus Research, Department of Veterinary Biosciences, The Ohio State University, Columbus, OH 43210, USA
| | - Zhihua Qin
- Center for Retrovirus Research, Department of Veterinary Biosciences, The Ohio State University, Columbus, OH 43210, USA
| | - Corine St Gelais
- Center for Retrovirus Research, Department of Veterinary Biosciences, The Ohio State University, Columbus, OH 43210, USA
| | - Li Wu
- Center for Retrovirus Research, Department of Veterinary Biosciences, The Ohio State University, Columbus, OH 43210, USA; Department of Microbial Infection and Immunity, The Ohio State University, Columbus, OH 43210, USA.
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28
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The structural basis for cancer drug interactions with the catalytic and allosteric sites of SAMHD1. Proc Natl Acad Sci U S A 2018; 115:E10022-E10031. [PMID: 30305425 DOI: 10.1073/pnas.1805593115] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
SAMHD1 is a deoxynucleoside triphosphate triphosphohydrolase (dNTPase) that depletes cellular dNTPs in noncycling cells to promote genome stability and to inhibit retroviral and herpes viral replication. In addition to being substrates, cellular nucleotides also allosterically regulate SAMHD1 activity. Recently, it was shown that high expression levels of SAMHD1 are also correlated with significantly worse patient responses to nucleotide analog drugs important for treating a variety of cancers, including acute myeloid leukemia (AML). In this study, we used biochemical, structural, and cellular methods to examine the interactions of various cancer drugs with SAMHD1. We found that both the catalytic and the allosteric sites of SAMHD1 are sensitive to sugar modifications of the nucleotide analogs, with the allosteric site being significantly more restrictive. We crystallized cladribine-TP, clofarabine-TP, fludarabine-TP, vidarabine-TP, cytarabine-TP, and gemcitabine-TP in the catalytic pocket of SAMHD1. We found that all of these drugs are substrates of SAMHD1 and that the efficacy of most of these drugs is affected by SAMHD1 activity. Of the nucleotide analogs tested, only cladribine-TP with a deoxyribose sugar efficiently induced the catalytically active SAMHD1 tetramer. Together, these results establish a detailed framework for understanding the substrate specificity and allosteric activation of SAMHD1 with regard to nucleotide analogs, which can be used to improve current cancer and antiviral therapies.
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29
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Coquel F, Neumayer C, Lin YL, Pasero P. SAMHD1 and the innate immune response to cytosolic DNA during DNA replication. Curr Opin Immunol 2018; 56:24-30. [PMID: 30292848 DOI: 10.1016/j.coi.2018.09.017] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 09/17/2018] [Accepted: 09/19/2018] [Indexed: 12/11/2022]
Abstract
Cytosolic DNA of endogenous or exogenous origin is sensed by the cGAS-STING pathway to activate innate immune responses. Besides microbial DNA, this pathway detects self-DNA in the cytoplasm of damaged or abnormal cells and plays a central role in antitumor immunity. The mechanism by which cytosolic DNA accumulates under genotoxic stress conditions is currently unclear, but recent studies on factors mutated in the Aicardi-Goutières syndrome cells, such as SAMHD1, RNase H2 and TREX1, are shedding new light on this key process. In particular, these studies indicate that the rupture of micronuclei and the release of ssDNA fragments during the processing of stalled replication forks and chromosome breaks represent potent inducers of the cGAS-STING pathway.
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Affiliation(s)
- Flavie Coquel
- Institut de Génétique Humaine, CNRS, Université de Montpellier, Equipe Labellisée Ligue contre le Cancer, Montpellier France
| | - Christoph Neumayer
- Institut de Génétique Humaine, CNRS, Université de Montpellier, Equipe Labellisée Ligue contre le Cancer, Montpellier France
| | - Yea-Lih Lin
- Institut de Génétique Humaine, CNRS, Université de Montpellier, Equipe Labellisée Ligue contre le Cancer, Montpellier France.
| | - Philippe Pasero
- Institut de Génétique Humaine, CNRS, Université de Montpellier, Equipe Labellisée Ligue contre le Cancer, Montpellier France.
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30
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From APOBEC to ZAP: Diverse mechanisms used by cellular restriction factors to inhibit virus infections. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2018; 1866:382-394. [PMID: 30290238 PMCID: PMC6334645 DOI: 10.1016/j.bbamcr.2018.09.012] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Revised: 08/28/2018] [Accepted: 09/23/2018] [Indexed: 12/30/2022]
Abstract
Antiviral restriction factors are cellular proteins that inhibit the entry, replication, or spread of viruses. These proteins are critical components of the innate immune system and function to limit the severity and host range of virus infections. Here we review the current knowledge on the mechanisms of action of several restriction factors that affect multiple viruses at distinct stages of their life cycles. For example, APOBEC3G deaminates cytosines to hypermutate reverse transcribed viral DNA; IFITM3 alters membranes to inhibit virus membrane fusion; MXA/B oligomerize on viral protein complexes to inhibit virus replication; SAMHD1 decreases dNTP intracellular concentrations to prevent reverse transcription of retrovirus genomes; tetherin prevents release of budding virions from cells; Viperin catalyzes formation of a nucleoside analogue that inhibits viral RNA polymerases; and ZAP binds virus RNAs to target them for degradation. We also discuss countermeasures employed by specific viruses against these restriction factors, and mention secondary functions of several of these factors in modulating immune responses. These important examples highlight the diverse strategies cells have evolved to combat virus infections.
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31
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USP18 (UBP43) Abrogates p21-Mediated Inhibition of HIV-1. J Virol 2018; 92:JVI.00592-18. [PMID: 30068654 DOI: 10.1128/jvi.00592-18] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Accepted: 07/25/2018] [Indexed: 12/17/2022] Open
Abstract
The host intrinsic innate immune system drives antiviral defenses and viral restriction, which includes the production of soluble factors, such as type I and III interferon (IFN), and activation of restriction factors, including SAMHD1, a deoxynucleoside triphosphohydrolase. Interferon-stimulated gene 15 (ISG15)-specific ubiquitin-like protease 43 (USP18) abrogates IFN signaling pathways. The cyclin-dependent kinase inhibitor p21 (CIP1/WAF1), which is involved in the differentiation and maturation of monocytes, inhibits human immunodeficiency virus type 1 (HIV-1) in macrophages and dendritic cells. p21 inhibition of HIV-1 replication is thought to occur at the reverse transcription step, likely by suppressing cellular deoxynucleoside triphosphate (dNTP) biosynthesis and increasing the amount of antivirally active form of SAMHD1. SAMHD1 strongly inhibits HIV-1 replication in myeloid and resting CD4+ T cells. Here, we studied how USP18 influences HIV-1 replication in human myeloid THP-1 cells. We found that USP18 has the novel ability to inhibit the antiviral function of p21 in differentiated THP-1 cells. USP18 enhanced reverse transcription of HIV-1 by downregulating p21 expression and upregulating intracellular dNTP levels. p21 downregulation by USP18 was associated with the active form of SAMHD1, phosphorylated at T592. USP18 formed a complex with the E3 ubiquitin ligase recognition factor SKP2 (S-phase kinase associated protein 2) and SAMHD1. CRISPR-Cas9 knockout of USP18 increased p21 protein expression and blocked HIV-1 replication. Overall, we propose USP18 as a regulator of p21 antiviral function in differentiated myeloid THP-1 cells.IMPORTANCE Macrophages and dendritic cells are usually the first point of contact with pathogens, including lentiviruses. Host restriction factors, including SAMHD1, mediate the innate immune response against these viruses. However, HIV-1 has evolved to circumvent the innate immune response and establishes disseminated infection. The cyclin-dependent kinase inhibitor p21, which is involved in differentiation and maturation of monocytes, blocks HIV-1 replication at the reverse transcription step. p21 is thought to suppress key enzymes involved in dNTP biosynthesis and activates SAMHD1 antiviral function. We report here that the human USP18 protein is a novel factor potentially contributing to HIV replication by blocking the antiviral function of p21 in differentiated human myeloid cells. USP18 downregulates p21 protein expression, which correlates with upregulated intracellular dNTP levels and the antiviral inactive form of SAMHD1. Depletion of USP18 stabilizes p21 protein expression, which correlates with dephosphorylated SAMHD1 and a block to HIV-1 replication.
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Lu W, Tirumuru N, St Gelais C, Koneru PC, Liu C, Kvaratskhelia M, He C, Wu L. N6-Methyladenosine-binding proteins suppress HIV-1 infectivity and viral production. J Biol Chem 2018; 293:12992-13005. [PMID: 29976753 PMCID: PMC6109920 DOI: 10.1074/jbc.ra118.004215] [Citation(s) in RCA: 68] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2018] [Revised: 06/27/2018] [Indexed: 11/06/2022] Open
Abstract
The internal N6-methyladenosine (m6A) modification of cellular mRNA regulates post-transcriptional gene expression. The YTH domain family proteins (YTHDF1-3 or Y1-3) bind to m6A-modified cellular mRNAs and modulate their metabolism and processing, thereby affecting cellular protein translation. We previously reported that HIV-1 RNA contains the m6A modification and that Y1-3 proteins inhibit HIV-1 infection by decreasing HIV-1 reverse transcription activity. Here, we investigated the mechanisms of Y1-3-mediated inhibition of HIV-1 infection in target cells and the effect of Y1-3 on viral production levels in virus-producing cells. We found that Y1-3 protein overexpression in HIV-1 target cells decreases viral genomic RNA (gRNA) levels and inhibits both early and late reverse transcription. Purified recombinant Y1-3 proteins preferentially bound to the m6A-modified 5' leader sequence of gRNA compared with its unmodified RNA counterpart, consistent with the strong binding of Y1-3 proteins to HIV-1 gRNA in infected cells. HIV-1 mutants with two altered m6A modification sites in the 5' leader sequence of gRNA exhibited significantly lower infectivity than WT, replication-competent HIV-1, confirming that these sites alter viral infection. HIV-1 produced from cells in which endogenous Y1, Y3, or Y1-3 proteins were knocked down singly or together had increased viral infectivity compared with HIV-1 produced in control cells. Interestingly, we found that Y1-3 proteins and HIV-1 Gag protein formed a complex with RNA in HIV-1-producing cells. Overall, these results indicate that Y1-3 proteins inhibit HIV-1 infection and provide new insights into the mechanisms by which the m6A modification of HIV-1 RNA affects viral replication.
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Affiliation(s)
- Wuxun Lu
- From the Center for Retrovirus Research, Department of Veterinary Biosciences, Ohio State University, Columbus, Ohio 43210
| | - Nagaraja Tirumuru
- From the Center for Retrovirus Research, Department of Veterinary Biosciences, Ohio State University, Columbus, Ohio 43210
| | - Corine St Gelais
- From the Center for Retrovirus Research, Department of Veterinary Biosciences, Ohio State University, Columbus, Ohio 43210
| | - Pratibha C Koneru
- the Division of Infectious Diseases, University of Colorado School of Medicine, Aurora, Colorado 80045, and
| | - Chang Liu
- the Departments of Chemistry and of Biochemistry and Molecular Biology, Institute for Biophysical Dynamics, and
- Howard Hughes Medical Institute, University of Chicago, Chicago, Illinois 60637
| | - Mamuka Kvaratskhelia
- the Division of Infectious Diseases, University of Colorado School of Medicine, Aurora, Colorado 80045, and
| | - Chuan He
- the Departments of Chemistry and of Biochemistry and Molecular Biology, Institute for Biophysical Dynamics, and
- Howard Hughes Medical Institute, University of Chicago, Chicago, Illinois 60637
| | - Li Wu
- From the Center for Retrovirus Research, Department of Veterinary Biosciences, Ohio State University, Columbus, Ohio 43210,
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Kim YC, Kim KK, Yoon J, Scott DW, Shevach EM. SAMHD1 Posttranscriptionally Controls the Expression of Foxp3 and Helios in Human T Regulatory Cells. THE JOURNAL OF IMMUNOLOGY 2018; 201:1671-1680. [PMID: 30104243 DOI: 10.4049/jimmunol.1800613] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Accepted: 07/12/2018] [Indexed: 01/18/2023]
Abstract
Clinical application of Ag-specific T regulatory cells (Tregs) offers promise for the treatment of undesirable immune diseases. To achieve this goal, long-term expansion of Tregs is required to obtain sufficient numbers of cells. However, human Tregs are not stable ex vivo. Therefore, we previously developed an innovative Treg expansion protocol using 25mer-phosphorothioated random oligonucleotides (ODNps25). The addition of ODNps25 successfully resulted in the stabilization of engineered Ag-specific Tregs; however, the mechanism is not fully characterized. We first identified sterile α motif histidine-aspartate-domain containing protein 1 (SAMHD1) as an ODNps25-binding protein using a UV-cross-linking pull-down strategy. SAMHD1 physically interacted with the 3' untranslated region of Foxp3 mRNA and was translocated from nucleus to cytoplasm after ODNps25 treatment. Importantly, addition of ODNps25 enhanced the interaction of SAMHD1 and Foxp3 mRNA significantly, and this interaction was increased by TCR stimulation. Because ODNps25 binds to the nuclease (HD) domain of SAMHD1, we then established that overexpression of a dNTPase-deficient mutant (D137N) in Tregs significantly stabilized the expression level of the Foxp3 protein. Furthermore, we found that TCR stimulation upregulates phosphorylation of the threonine residue (Thr592), which is a regulatory site to control SAMHD1 activity, and phosphorylation of Thr592 is critical to control SAMHD1 activity to stabilize the expression of Foxp3 and Helios in Tregs. Taken together, we suggest that the interaction of ODNPs25 in HD or phosphorylation of Thr592 by TCR stimulation interferes with nuclease activity of SAMHD1, thereby stabilizing 3' untranslated region of Foxp3 and Helios mRNAs in long-term culture.
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Affiliation(s)
- Yong Chan Kim
- Department of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD 20814
| | - Kee Kwang Kim
- Department of Biochemistry, Chungnam National University, 34134 Daejeon, South Korea; and
| | - Jeongheon Yoon
- Department of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD 20814
| | - David W Scott
- Department of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD 20814;
| | - Ethan M Shevach
- Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20814
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Antonucci JM, Kim SH, St Gelais C, Bonifati S, Li TW, Buzovetsky O, Knecht KM, Duchon AA, Xiong Y, Musier-Forsyth K, Wu L. SAMHD1 Impairs HIV-1 Gene Expression and Negatively Modulates Reactivation of Viral Latency in CD4 + T Cells. J Virol 2018; 92:e00292-18. [PMID: 29793958 PMCID: PMC6052313 DOI: 10.1128/jvi.00292-18] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Accepted: 05/15/2018] [Indexed: 11/20/2022] Open
Abstract
Sterile alpha motif and HD domain-containing protein 1 (SAMHD1) restricts human immunodeficiency virus type 1 (HIV-1) replication in nondividing cells by degrading intracellular deoxynucleoside triphosphates (dNTPs). SAMHD1 is highly expressed in resting CD4+ T cells, which are important for the HIV-1 reservoir and viral latency; however, whether SAMHD1 affects HIV-1 latency is unknown. Recombinant SAMHD1 binds HIV-1 DNA or RNA fragments in vitro, but the function of this binding remains unclear. Here we investigate the effect of SAMHD1 on HIV-1 gene expression and reactivation of viral latency. We found that endogenous SAMHD1 impaired HIV-1 long terminal repeat (LTR) activity in monocytic THP-1 cells and HIV-1 reactivation in latently infected primary CD4+ T cells. Overexpression of wild-type (WT) SAMHD1 suppressed HIV-1 LTR-driven gene expression at a transcriptional level. Tat coexpression abrogated SAMHD1-mediated suppression of HIV-1 LTR-driven luciferase expression. SAMHD1 overexpression also suppressed the LTR activity of human T-cell leukemia virus type 1 (HTLV-1), but not that of murine leukemia virus (MLV), suggesting specific suppression of retroviral LTR-driven gene expression. WT SAMHD1 bound to proviral DNA and impaired reactivation of HIV-1 gene expression in latently infected J-Lat cells. In contrast, a nonphosphorylated mutant (T592A) and a dNTP triphosphohydrolase (dNTPase) inactive mutant (H206D R207N [HD/RN]) of SAMHD1 failed to efficiently suppress HIV-1 LTR-driven gene expression and reactivation of latent virus. Purified recombinant WT SAMHD1, but not the T592A and HD/RN mutants, bound to fragments of the HIV-1 LTR in vitro These findings suggest that SAMHD1-mediated suppression of HIV-1 LTR-driven gene expression potentially regulates viral latency in CD4+ T cells.IMPORTANCE A critical barrier to developing a cure for HIV-1 infection is the long-lived viral reservoir that exists in resting CD4+ T cells, the main targets of HIV-1. The viral reservoir is maintained through a variety of mechanisms, including regulation of the HIV-1 LTR promoter. The host protein SAMHD1 restricts HIV-1 replication in nondividing cells, but its role in HIV-1 latency remains unknown. Here we report a new function of SAMHD1 in regulating HIV-1 latency. We found that SAMHD1 suppressed HIV-1 LTR promoter-driven gene expression and reactivation of viral latency in cell lines and primary CD4+ T cells. Furthermore, SAMHD1 bound to the HIV-1 LTR in vitro and in a latently infected CD4+ T-cell line, suggesting that the binding may negatively modulate reactivation of HIV-1 latency. Our findings indicate a novel role for SAMHD1 in regulating HIV-1 latency, which enhances our understanding of the mechanisms regulating proviral gene expression in CD4+ T cells.
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Affiliation(s)
- Jenna M Antonucci
- Center for Retrovirus Research, The Ohio State University, Columbus, Ohio, USA
- Department of Veterinary Biosciences, The Ohio State University, Columbus, Ohio, USA
- Department of Microbiology, The Ohio State University, Columbus, Ohio, USA
| | - Sun Hee Kim
- Center for Retrovirus Research, The Ohio State University, Columbus, Ohio, USA
- Department of Veterinary Biosciences, The Ohio State University, Columbus, Ohio, USA
| | - Corine St Gelais
- Center for Retrovirus Research, The Ohio State University, Columbus, Ohio, USA
- Department of Veterinary Biosciences, The Ohio State University, Columbus, Ohio, USA
| | - Serena Bonifati
- Center for Retrovirus Research, The Ohio State University, Columbus, Ohio, USA
- Department of Veterinary Biosciences, The Ohio State University, Columbus, Ohio, USA
| | - Tai-Wei Li
- Center for Retrovirus Research, The Ohio State University, Columbus, Ohio, USA
- Department of Veterinary Biosciences, The Ohio State University, Columbus, Ohio, USA
| | - Olga Buzovetsky
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, USA
| | - Kirsten M Knecht
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, USA
| | - Alice A Duchon
- Center for Retrovirus Research, The Ohio State University, Columbus, Ohio, USA
- Center for RNA Biology, The Ohio State University, Columbus, Ohio, USA
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio, USA
| | - Yong Xiong
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, USA
| | - Karin Musier-Forsyth
- Center for Retrovirus Research, The Ohio State University, Columbus, Ohio, USA
- Center for RNA Biology, The Ohio State University, Columbus, Ohio, USA
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio, USA
| | - Li Wu
- Center for Retrovirus Research, The Ohio State University, Columbus, Ohio, USA
- Department of Veterinary Biosciences, The Ohio State University, Columbus, Ohio, USA
- Department of Microbiology, The Ohio State University, Columbus, Ohio, USA
- Center for RNA Biology, The Ohio State University, Columbus, Ohio, USA
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Tramentozzi E, Ferraro P, Hossain M, Stillman B, Bianchi V, Pontarin G. The dNTP triphosphohydrolase activity of SAMHD1 persists during S-phase when the enzyme is phosphorylated at T592. Cell Cycle 2018; 17:1102-1114. [PMID: 30039733 PMCID: PMC6110608 DOI: 10.1080/15384101.2018.1480216] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Revised: 06/01/2018] [Accepted: 05/16/2018] [Indexed: 01/31/2023] Open
Abstract
SAMHD1 is the major catabolic enzyme regulating the intracellular concentrations of DNA precursors (dNTPs). The S-phase kinase CDK2-cyclinA phosphorylates SAMHD1 at Thr-592. How this modification affects SAMHD1 function is highly debated. We investigated the role of endogenous SAMHD1 phosphorylation during the cell cycle. Thr-592 phosphorylation occurs first at the G1/S border and is removed during mitotic exit parallel with Thr-phosphorylations of most CDK1 targets. Differential sensitivity to the phosphatase inhibitor okadaic acid suggested different involvement of the PP1 and PP2 families dependent upon the time of the cell cycle. SAMHD1 turn-over indicates that Thr-592 phosphorylation does not cause rapid protein degradation. Furthermore, SAMHD1 influenced the size of the four dNTP pools independently of its phosphorylation. Our findings reveal that SAMHD1 is active during the entire cell cycle and performs an important regulatory role during S-phase by contributing with ribonucleotide reductase to maintain dNTP pool balance for proper DNA replication.
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Affiliation(s)
| | - Paola Ferraro
- Department of Biology, University of Padova, Padova, Italy
| | - Manzar Hossain
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
| | - Bruce Stillman
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
| | - Vera Bianchi
- Department of Biology, University of Padova, Padova, Italy
| | - Giovanna Pontarin
- Department of Biology, University of Padova, Padova, Italy
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
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Lin X, Ammosova T, Kumari N, Nekhai S. Protein Phosphatase-1 -targeted Small Molecules, Iron Chelators and Curcumin Analogs as HIV-1 Antivirals. Curr Pharm Des 2018; 23:4122-4132. [PMID: 28677499 DOI: 10.2174/1381612823666170704123620] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Revised: 06/14/2017] [Accepted: 06/22/2017] [Indexed: 02/07/2023]
Abstract
BACKGROUND Despite efficient suppression of HIV-1 replication, current antiviral drugs are not able to eradicate HIV-1 infection. Permanent HIV-1 suppression or complete eradication requires novel biological approaches and therapeutic strategies. Our previous studies showed that HIV-1 transcription is regulated by host cell protein phosphatase-1. We also showed that HIV-1 transcription is sensitive to the reduction of intracellular iron that affects cell cycle-dependent kinase 2. We developed protein phosphatase 1-targeting small molecules that inhibited HIV-1 transcription. We also found an additional class of protein phosphatase-1-targeting molecules that activated HIV-1 transcription and reported HIV-1 inhibitory iron chelators and novel curcumin analogs that inhibit HIV-1. Here, we review HIV-1 transcription and replication with focus on its regulation by protein phosphatase 1 and cell cycle dependent kinase 2 and describe novel small molecules that can serve as future leads for anti-HIV drug development. RESULTS Our review describes in a non-exhaustive manner studies in which HIV-1 transcription and replication are targeted with small molecules. Previously, published studies show that HIV-1 can be inhibited with protein phosphatase-1-targeting and iron chelating compounds and curcumin analogs. These results are significant in light of the current efforts to eradicate HIV-1 through permanent inhibition. Also, HIV-1 activating compounds can be useful for "kick and kill" therapy in which the virus is reactivated prior to its inhibition by the combination antiretroviral therapy. CONCLUSION The studies described in our review point to protein phosphatase-1 as a new drug target, intracellular iron as subject for iron chelation and novel curcumin analogs that can be developed for novel HIV-1 transcription- targeting therapeutics.
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Affiliation(s)
- Xionghao Lin
- Center for Sickle Cell Disease, 1840 7th Street, N.W. HURB1, Suite 202, Washington DC 20001. United States
| | - Tatyana Ammosova
- Center for Sickle Cell Disease, 1840 7th Street, N.W. HURB1, Suite 202, Washington DC 20001. United States
| | - Namita Kumari
- Center for Sickle Cell Disease, 1840 7th Street, N.W. HURB1, Suite 202, Washington DC 20001. United States
| | - Sergei Nekhai
- Center for Sickle Cell Disease, 1840 7th Street, N.W. HURB1, Suite 202, Washington DC 20001. United States
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37
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Schott K, Fuchs NV, Derua R, Mahboubi B, Schnellbächer E, Seifried J, Tondera C, Schmitz H, Shepard C, Brandariz-Nuñez A, Diaz-Griffero F, Reuter A, Kim B, Janssens V, König R. Dephosphorylation of the HIV-1 restriction factor SAMHD1 is mediated by PP2A-B55α holoenzymes during mitotic exit. Nat Commun 2018; 9:2227. [PMID: 29884836 PMCID: PMC5993806 DOI: 10.1038/s41467-018-04671-1] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Accepted: 05/15/2018] [Indexed: 12/20/2022] Open
Abstract
SAMHD1 is a critical restriction factor for HIV-1 in non-cycling cells and its antiviral activity is regulated by T592 phosphorylation. Here, we show that SAMHD1 dephosphorylation at T592 is controlled during the cell cycle, occurring during M/G1 transition in proliferating cells. Using several complementary proteomics and biochemical approaches, we identify the phosphatase PP2A-B55α responsible for rendering SAMHD1 antivirally active. SAMHD1 is specifically targeted by PP2A-B55α holoenzymes during mitotic exit, in line with observations that PP2A-B55α is a key mitotic exit phosphatase in mammalian cells. Strikingly, as HeLa or activated primary CD4+ T cells enter the G1 phase, pronounced reduction of RT products is observed upon HIV-1 infection dependent on the presence of dephosphorylated SAMHD1. Moreover, PP2A controls SAMHD1 pT592 level in non-cycling monocyte-derived macrophages (MDMs). Thus, the PP2A-B55α holoenzyme is a key regulator to switch on the antiviral activity of SAMHD1.
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Affiliation(s)
- Kerstin Schott
- Host-Pathogen Interactions, Paul-Ehrlich-Institut, 63225, Langen, Germany
| | - Nina V Fuchs
- Host-Pathogen Interactions, Paul-Ehrlich-Institut, 63225, Langen, Germany
| | - Rita Derua
- Department of Cellular and Molecular Medicine, Laboratory of Protein Phosphorylation and Proteomics, KU Leuven, 3000, Leuven, Belgium.,Facility for Systems Biology based Mass Spectrometry (SYBIOMA), KU Leuven, 3000, Leuven, Belgium
| | - Bijan Mahboubi
- Center for Drug Discovery, Department of Pediatrics, Emory University, Children's Healthcare of Atlanta, Atlanta, GA, 30322, USA
| | | | - Janna Seifried
- Host-Pathogen Interactions, Paul-Ehrlich-Institut, 63225, Langen, Germany
| | - Christiane Tondera
- Host-Pathogen Interactions, Paul-Ehrlich-Institut, 63225, Langen, Germany
| | - Heike Schmitz
- Host-Pathogen Interactions, Paul-Ehrlich-Institut, 63225, Langen, Germany
| | - Caitlin Shepard
- Center for Drug Discovery, Department of Pediatrics, Emory University, Children's Healthcare of Atlanta, Atlanta, GA, 30322, USA
| | - Alberto Brandariz-Nuñez
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Felipe Diaz-Griffero
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Andreas Reuter
- Division of Allergology, Paul-Ehrlich-Institut, 63225, Langen, Germany
| | - Baek Kim
- Center for Drug Discovery, Department of Pediatrics, Emory University, Children's Healthcare of Atlanta, Atlanta, GA, 30322, USA.,Department of Pharmacy, Kyung-Hee University, 2447, Seoul, South Korea
| | - Veerle Janssens
- Department of Cellular and Molecular Medicine, Laboratory of Protein Phosphorylation and Proteomics, KU Leuven, 3000, Leuven, Belgium
| | - Renate König
- Host-Pathogen Interactions, Paul-Ehrlich-Institut, 63225, Langen, Germany. .,Immunity and Pathogenesis Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, 92037, USA. .,German Center for Infection Research (DZIF), 63225, Langen, Germany.
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Hu J, Qiao M, Chen Y, Tang H, Zhang W, Tang D, Pi S, Dai J, Tang N, Huang A, Hu Y. Cyclin E2-CDK2 mediates SAMHD1 phosphorylation to abrogate its restriction of HBV replication in hepatoma cells. FEBS Lett 2018; 592:1893-1904. [PMID: 29782647 DOI: 10.1002/1873-3468.13105] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2018] [Revised: 04/28/2018] [Accepted: 05/12/2018] [Indexed: 12/19/2022]
Abstract
SAMHD1 inhibits Hepatitis B virus (HBV) replication by reducing the intracellular dNTP levels. However, how SAMHD1 phosphorylation is regulated to abrogate its restriction of HBV replication in hepatoma cells is poorly understood. Here, we show that HBV replication and SAMHD1 phosphorylation levels are significantly reduced by knocking down cyclin-dependent kinase (CDK) 2 expression or in the presence of a CDK2 inhibitor. SAMHD1 binds to CDK2 in hepatocarcinoma cells, and this interaction does not require the HBV core protein. Furthermore, cyclin E2 participates in regulating viral replication through the CDK2/SAMHD1 phosphorylation pathway in an HBV infection system. Collectively, our results provide evidence that CDK2 has a greater role in regulating SAMHD1 phosphorylation and HBV replication than CDK1 or CDK6.
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Affiliation(s)
- Jie Hu
- Key Laboratory of Molecular Biology on Infectious Diseases, Ministry of Education, Department of Infectious Diseases, Institute for Viral Hepatitis, Second Affiliated Hospital, Chongqing Medical University, China
| | - Miao Qiao
- Key Laboratory of Molecular Biology on Infectious Diseases, Ministry of Education, Department of Infectious Diseases, Institute for Viral Hepatitis, Second Affiliated Hospital, Chongqing Medical University, China
| | - Yanmeng Chen
- Key Laboratory of Molecular Biology on Infectious Diseases, Ministry of Education, Department of Infectious Diseases, Institute for Viral Hepatitis, Second Affiliated Hospital, Chongqing Medical University, China
| | - Hua Tang
- Key Laboratory of Molecular Biology on Infectious Diseases, Ministry of Education, Department of Infectious Diseases, Institute for Viral Hepatitis, Second Affiliated Hospital, Chongqing Medical University, China
| | - Wenlu Zhang
- Key Laboratory of Molecular Biology on Infectious Diseases, Ministry of Education, Department of Infectious Diseases, Institute for Viral Hepatitis, Second Affiliated Hospital, Chongqing Medical University, China
| | - Dan Tang
- Endocrinology Department, Chengdu First People's Hospital, Chengdu, China
| | - Sidie Pi
- Key Laboratory of Molecular Biology on Infectious Diseases, Ministry of Education, Department of Infectious Diseases, Institute for Viral Hepatitis, Second Affiliated Hospital, Chongqing Medical University, China
| | - Juan Dai
- Key Laboratory of Molecular Biology on Infectious Diseases, Ministry of Education, Department of Infectious Diseases, Institute for Viral Hepatitis, Second Affiliated Hospital, Chongqing Medical University, China
| | - Ni Tang
- Key Laboratory of Molecular Biology on Infectious Diseases, Ministry of Education, Department of Infectious Diseases, Institute for Viral Hepatitis, Second Affiliated Hospital, Chongqing Medical University, China
| | - Ailong Huang
- Key Laboratory of Molecular Biology on Infectious Diseases, Ministry of Education, Department of Infectious Diseases, Institute for Viral Hepatitis, Second Affiliated Hospital, Chongqing Medical University, China
| | - Yuan Hu
- Key Laboratory of Molecular Biology on Infectious Diseases, Ministry of Education, Department of Infectious Diseases, Institute for Viral Hepatitis, Second Affiliated Hospital, Chongqing Medical University, China
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Lentiviral infection of proliferating brain macrophages in HIV and simian immunodeficiency virus encephalitis despite sterile alpha motif and histidine-aspartate domain-containing protein 1 expression. AIDS 2018; 32:965-974. [PMID: 29698322 PMCID: PMC5943146 DOI: 10.1097/qad.0000000000001793] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Objective: HIV-1 infection of the brain and related cognitive impairment remain prevalent in HIV-1-infected individuals despite combination antiretroviral therapy. Sterile alpha motif and histidine-aspartate domain-containing protein 1 (SAMHD1) is a newly identified host restriction factor that blocks the replication of HIV-1 and other retroviruses in myeloid cells. Cell cycle-regulated phosphorylation at residue Thr592 and viral protein X (Vpx)-mediated degradation of SAMHD1 have been shown to bypass SAMHD1 restriction in vitro. Herein, we investigated expression and phosphorylation of SAMHD1 in vivo in relation to macrophage infection and proliferation during the neuropathogenesis of HIV-1 and simian immunodeficiency virus (SIV) encephalitis. Methods: Using brain and other tissues from uninfected and SIV-infected macaques with or without encephalitis, we performed immunohistochemistry, multilabel fluorescence microscopy and western blot to examine the expression, localization and phosphorylation of SAMHD1. Results: The number of SAMHD1+ nuclei increased in encephalitic brains despite the presence of Vpx. Many of these cells were perivascular macrophages, although subsets of SAMHD1+ microglia and endothelial cells were also observed. The SAMHD1+ macrophages were shown to be both infected and proliferating. Moreover, the presence of cycling SAMHD1+ brain macrophages was confirmed in the tissue of HIV-1-infected patients with encephalitis. Finally, western blot analysis of brain-protein extracts from SIV-infected macaques showed that SAMHD1 protein exists in the brain mainly as an inactive Thr592-phosphorylated form. Conclusion: The ability of SAMHD1 to act as a restriction factor for SIV/HIV in the brain is likely bypassed in proliferating brain macrophages through the phosphorylation-mediated inactivation, not Vpx-mediated degradation of SAMHD1.
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40
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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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41
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SAMHD1 suppresses innate immune responses to viral infections and inflammatory stimuli by inhibiting the NF-κB and interferon pathways. Proc Natl Acad Sci U S A 2018; 115:E3798-E3807. [PMID: 29610295 DOI: 10.1073/pnas.1801213115] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Sterile alpha motif and HD-domain-containing protein 1 (SAMHD1) blocks replication of retroviruses and certain DNA viruses by reducing the intracellular dNTP pool. SAMHD1 has been suggested to down-regulate IFN and inflammatory responses to viral infections, although the functions and mechanisms of SAMHD1 in modulating innate immunity remain unclear. Here, we show that SAMHD1 suppresses the innate immune responses to viral infections and inflammatory stimuli by inhibiting nuclear factor-κB (NF-κB) activation and type I interferon (IFN-I) induction. Compared with control cells, infection of SAMHD1-silenced human monocytic cells or primary macrophages with Sendai virus (SeV) or HIV-1, or treatment with inflammatory stimuli, induces significantly higher levels of NF-κB activation and IFN-I induction. Exogenous SAMHD1 expression in cells or SAMHD1 reconstitution in knockout cells suppresses NF-κB activation and IFN-I induction by SeV infection or inflammatory stimuli. Mechanistically, SAMHD1 inhibits NF-κB activation by interacting with NF-κB1/2 and reducing phosphorylation of the NF-κB inhibitory protein IκBα. SAMHD1 also interacts with the inhibitor-κB kinase ε (IKKε) and IFN regulatory factor 7 (IRF7), leading to the suppression of the IFN-I induction pathway by reducing IKKε-mediated IRF7 phosphorylation. Interactions of endogenous SAMHD1 with NF-κB and IFN-I pathway proteins were validated in human monocytic cells and primary macrophages. Comparing splenocytes from SAMHD1 knockout and heterozygous mice, we further confirmed SAMHD1-mediated suppression of NF-κB activation, suggesting an evolutionarily conserved property of SAMHD1. Our findings reveal functions of SAMHD1 in down-regulating innate immune responses to viral infections and inflammatory stimuli, highlighting the importance of SAMHD1 in modulating antiviral immunity.
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Herrmann A, Wittmann S, Thomas D, Shepard CN, Kim B, Ferreirós N, Gramberg T. The SAMHD1-mediated block of LINE-1 retroelements is regulated by phosphorylation. Mob DNA 2018; 9:11. [PMID: 29610582 PMCID: PMC5872582 DOI: 10.1186/s13100-018-0116-5] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Accepted: 03/19/2018] [Indexed: 12/22/2022] Open
Abstract
Background The restriction factor SAMHD1 regulates intracellular nucleotide level by degrading dNTPs and blocks the replication of retroviruses and DNA viruses in non-cycling cells, like macrophages or dendritic cells. In patients, inactivating mutations in samhd1 are associated with the autoimmune disease Aicardi-Goutières Syndrome (AGS). The accumulation of intracellular nucleic acids derived from endogenous retroelements thriving in the absence of SAMHD1 has been discussed as potential trigger of the autoimmune reaction. In vitro, SAMHD1 has been found to restrict endogenous retroelements, like LINE-1 elements (L1). The mechanism, however, by which SAMHD1 blocks endogenous retroelements, is still unclear. Results Here, we show that SAMHD1 inhibits the replication of L1 and other endogenous retroelements in cycling cells. By applying GFP- and neomycin-based reporter assays we found that the anti-L1 activity of SAMHD1 is regulated by phosphorylation at threonine 592 (T592). Similar to the block of HIV, the cofactor binding site and the enzymatic active HD domain of SAMHD1 proofed to be essential for restriction of L1 elements. However, phosphorylation at T592 did not correlate with the dNTP hydrolase activity of SAMHD1 in cycling 293T cells suggesting an alternative mechanism of regulation. Interestingly, we found that SAMHD1 binds to ORF2 protein of L1 and that this interaction is regulated by T592 phosphorylation. Together with the finding that the block is also active in cycling cells, our results suggest that the SAMHD1-mediated inhibition of L1 is similar but not identical to HIV restriction. Conclusion Our findings show conclusively that SAMHD1 restricts the replication of endogenous retroelements in vitro. The results suggest that SAMHD1 is important for maintaining genome integrity and support the idea of an enhanced replication of endogenous retroelements in the absence of SAMHD1 in vivo, potentially triggering autoimmune diseases like AGS. Our analysis also contributes to the better understanding of the activities of SAMHD1 in antiviral defense and nucleotide metabolism. The finding that the phosphorylation of SAMHD1 at T592 regulates its activity against retroelements but not necessarily intracellular dNTP level suggests that the dNTP hydrolase activity might not be the only function of SAMHD1 important for its antiviral activity and for controlling autoimmunity. Electronic supplementary material The online version of this article (10.1186/s13100-018-0116-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Alexandra Herrmann
- 1Institute of Clinical and Molecular Virology, Friedrich-Alexander University Erlangen-Nürnberg, Schlossgarten 4, 91054 Erlangen, Germany
| | - Sabine Wittmann
- 1Institute of Clinical and Molecular Virology, Friedrich-Alexander University Erlangen-Nürnberg, Schlossgarten 4, 91054 Erlangen, Germany
| | - Dominique Thomas
- 2pharmazentrum frankfurt/ZAFES, Institute of Clinical Pharmacology, Goethe-University, Theodor Stern Kai 7, 60590 Frankfurt am Main, Germany
| | - Caitlin N Shepard
- 3Center for Drug Discovery, Department of Pediatrics, Emory Center for AIDS Research, Emory University, Children's Healthcare of Atlanta, Atlanta, GA 30322 USA
| | - Baek Kim
- 3Center for Drug Discovery, Department of Pediatrics, Emory Center for AIDS Research, Emory University, Children's Healthcare of Atlanta, Atlanta, GA 30322 USA.,4College of Pharmacy, Kyung-Hee University, Seoul, South Korea
| | - Nerea Ferreirós
- 2pharmazentrum frankfurt/ZAFES, Institute of Clinical Pharmacology, Goethe-University, Theodor Stern Kai 7, 60590 Frankfurt am Main, Germany
| | - Thomas Gramberg
- 1Institute of Clinical and Molecular Virology, Friedrich-Alexander University Erlangen-Nürnberg, Schlossgarten 4, 91054 Erlangen, Germany
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Bakir TM. The role of SAMHD1 expression and its relation to HIV-2 (Vpx) gene production. Saudi Pharm J 2018; 26:903-908. [PMID: 30202235 PMCID: PMC6128726 DOI: 10.1016/j.jsps.2018.03.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Accepted: 03/10/2018] [Indexed: 11/21/2022] Open
Abstract
SAMHD1 (sterile alpha motif and HD domain 1) is a protein that is found in myeloid cells, which restricts HIV1 replication. It depletes the de-oxy-nucleoside tri-phosphate (dNTPs) pool needed for a viral cDNA synthesis leading to inhibition of viral replication inside the cells. However, it does not restrict HIV2 replication in myeloid cells due to the presence of viral Vpx protein. Vpx is a virion-associated protein which augments viral infectivity and it only exists in HIV2 and it has been recently shown in Simian Immunodeficiency Virus (SIV) and which can induce degradation of SAMHD1 protein. This increases the amount of dNTPs for viral reverse transcription in cytoplasm and HIV infection. HIV2 reverse transcription is believed to be less active than HIV1 and this could be the reason for the absence of Vpx from HIV1. Protein expression and interaction between Vpx and SAMHD1 remains unclear. The interaction of SAMHD1 and HIV2-VPx patients' cells can be considered as a first step to help in the development for more effective anti-HIV drugs and possible novel intervention therapy in the future. Present review article provides comprehensive insights on the above issue. We performed a comprehensive literature search in the bibliographic database “Pubmed,” looking at studies discussing the SAMHDI and Vpx interactions.
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A Cyclin-Binding Motif in Human SAMHD1 Is Required for Its HIV-1 Restriction, dNTPase Activity, Tetramer Formation, and Efficient Phosphorylation. J Virol 2018; 92:JVI.01787-17. [PMID: 29321329 DOI: 10.1128/jvi.01787-17] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Accepted: 12/22/2017] [Indexed: 12/22/2022] Open
Abstract
Sterile alpha motif and HD domain-containing protein 1 (SAMHD1) regulates intracellular deoxynucleoside triphosphate (dNTP) levels and functions as a retroviral restriction factor through its dNTP triphosphohydrolase (dNTPase) activity. Human SAMHD1 interacts with cell cycle regulatory proteins cyclin A2, cyclin-dependent kinase 1 (CDK1), and CDK2. This interaction mediates phosphorylation of SAMHD1 at threonine 592 (T592), which negatively regulates HIV-1 restriction. We previously reported that the interaction is mediated, at least in part, through a cyclin-binding motif (RXL, amino acids [aa] 451 to 453). To understand the role of the RXL motif in regulating SAMHD1 activity, we performed structural and functional analyses of RXL mutants and the effect on HIV-1 restriction. We found that the RXL mutation (R451A and L453A, termed RL/AA) disrupted SAMHD1 tetramer formation and abolished its dNTPase activity in vitro and in cells. Compared to wild-type (WT) SAMHD1, the RL/AA mutant failed to restrict HIV-1 infection and had reduced binding to cyclin A2. WT SAMHD1 and RL/AA mutant proteins were degraded by Vpx from HIV-2 but were not spontaneously ubiquitinated in the absence of Vpx. Analysis of proteasomal and autophagy degradation revealed that WT and RL/AA SAMHD1 protein levels were enhanced only when both pathways of degradation were simultaneously inhibited. Our results demonstrate that the RXL motif of human SAMHD1 is required for its HIV-1 restriction, tetramer formation, dNTPase activity, and efficient phosphorylation at T592. These findings identify a new functional domain of SAMHD1 important for its structural integrity, enzyme activity, phosphorylation, and HIV-1 restriction.IMPORTANCE SAMHD1 is the first mammalian dNTPase identified as a restriction factor that inhibits HIV-1 replication by decreasing the intracellular dNTP pool in nondividing cells, although the critical mechanisms regulating SAMHD1 function remain unclear. We previously reported that mutations of a cyclin-binding RXL motif in human SAMHD1 significantly affect protein expression levels, half-life, nuclear localization, and phosphorylation, suggesting an important role of this motif in modulating SAMHD1 functions in cells. To further understand the significance and mechanisms of the RXL motif in regulating SAMHD1 activity, we performed structural and functional analyses of the RXL motif mutation and its effect on HIV-1 restriction. Our results indicate that the RXL motif is critical for tetramer formation, dNTPase activity, and HIV-1 restriction. These findings help us understand SAMHD1 interactions with other host proteins and the mechanisms regulating SAMHD1 structure and functions in cells.
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45
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Buzovetsky O, Tang C, Knecht KM, Antonucci JM, Wu L, Ji X, Xiong Y. The SAM domain of mouse SAMHD1 is critical for its activation and regulation. Nat Commun 2018; 9:411. [PMID: 29379009 PMCID: PMC5788916 DOI: 10.1038/s41467-017-02783-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Accepted: 12/28/2017] [Indexed: 11/09/2022] Open
Abstract
Human SAMHD1 (hSAMHD1) is a retroviral restriction factor that blocks HIV-1 infection by depleting the cellular nucleotides required for viral reverse transcription. SAMHD1 is allosterically activated by nucleotides that induce assembly of the active tetramer. Although the catalytic core of hSAMHD1 has been studied extensively, previous structures have not captured the regulatory SAM domain. Here we report the crystal structure of full-length SAMHD1 by capturing mouse SAMHD1 (mSAMHD1) structures in three different nucleotide bound states. Although mSAMHD1 and hSAMHD1 are highly similar in sequence and function, we find that mSAMHD1 possesses a more complex nucleotide-induced activation process, highlighting the regulatory role of the SAM domain. Our results provide insights into the regulation of SAMHD1 activity, thereby facilitating the improvement of HIV mouse models and the development of new therapies for certain cancers and autoimmune diseases.
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Affiliation(s)
- Olga Buzovetsky
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, 06520, USA
| | - Chenxiang Tang
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, 06520, USA
| | - Kirsten M Knecht
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, 06520, USA
| | - Jenna M Antonucci
- Center of Retrovirus Research, Department of Veterinary Biosciences, The Ohio State University, Columbus, OH, 43210, USA
| | - Li Wu
- Center of Retrovirus Research, Department of Veterinary Biosciences, The Ohio State University, Columbus, OH, 43210, USA
| | - Xiaoyun Ji
- The State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, Jiangsu, 210023, China.
| | - Yong Xiong
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, 06520, USA.
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46
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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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47
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Jobe O, Kim J, Tycksen E, Onkar S, Michael NL, Alving CR, Rao M. Human Primary Macrophages Derived In Vitro from Circulating Monocytes Comprise Adherent and Non-Adherent Subsets with Differential Expression of Siglec-1 and CD4 and Permissiveness to HIV-1 Infection. Front Immunol 2017; 8:1352. [PMID: 29123518 PMCID: PMC5662875 DOI: 10.3389/fimmu.2017.01352] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Accepted: 10/03/2017] [Indexed: 12/18/2022] Open
Abstract
Macrophages are a major target for human immunodeficiency virus type 1 (HIV-1) infection. However, macrophages are largely heterogeneous and may exhibit differences in permissiveness to HIV-1 infection. This study highlights the interplay of macrophage heterogeneity in HIV-1 pathogenesis. We show that monocyte-derived macrophages (MDMs) could be divided into two distinct subsets: CD14+Siglec-1hiCD4+ (non-adherent MDM) and CD14+Siglec-1LoCD4− (adherent MDM). The CD14+Siglec-1hiCD4+MDM subset represented the smaller proportion in the macrophage pool, and varied among different donors. Fractionation and subsequent exposure of the two MDM subsets to HIV-1 revealed opposite outcomes in terms of HIV-1 capture and infection. Although the CD14+Siglec-1hiCD4+MDM captured significantly more HIV-1, infection was significantly higher in the CD14+Siglec-1LoCD4−MDM subset. Thus, CD14+Siglec-1hiCD4+MDM were less permissive to infection. Depletion of CD14+Siglec-1hiCD4+MDM or a decrease in their percentage, resulted in increased infection of MDM, suggestive of a capacity of these cells to capture and sequester HIV-1 in an environment that hinders its infectivity. Increased expression of innate restriction factors and cytokine genes were observed in the non-adherent CD14+Siglec-1hiCD4+MDM, both before and after HIV-1 infection, compared to the adherent CD14+Siglec-1LoCD4−MDM. We speculate that the differential expression of gene expression profiles in the two macrophage subsets may provide an explanation for the differences observed in HIV-1 infectivity.
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Affiliation(s)
- Ousman Jobe
- U.S. Military HIV Research Program, Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, MD, United States.,Laboratory of Adjuvant and Antigen Research, U.S. Military HIV Research Program, Walter Reed Army Institute of Research, Silver Spring, MD, United States
| | - Jiae Kim
- U.S. Military HIV Research Program, Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, MD, United States.,Laboratory of Adjuvant and Antigen Research, U.S. Military HIV Research Program, Walter Reed Army Institute of Research, Silver Spring, MD, United States
| | - Eric Tycksen
- Genome Technology Access Center, Department of Genetics, Washington University in St. Louis, St. Louis, MO, United States
| | - Sayali Onkar
- U.S. Military HIV Research Program, Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, MD, United States.,Laboratory of Adjuvant and Antigen Research, U.S. Military HIV Research Program, Walter Reed Army Institute of Research, Silver Spring, MD, United States
| | - Nelson L Michael
- Laboratory of Molecular Virology and Pathogenesis, Host Genetics Section, U.S. Military HIV Research Program, Walter Reed Army Institute of Research, Silver Spring, MD, United States
| | - Carl R Alving
- Laboratory of Adjuvant and Antigen Research, U.S. Military HIV Research Program, Walter Reed Army Institute of Research, Silver Spring, MD, United States
| | - Mangala Rao
- Laboratory of Adjuvant and Antigen Research, U.S. Military HIV Research Program, Walter Reed Army Institute of Research, Silver Spring, MD, United States
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Herold N, Rudd SG, Sanjiv K, Kutzner J, Myrberg IH, Paulin CBJ, Olsen TK, Helleday T, Henter JI, Schaller T. With me or against me: Tumor suppressor and drug resistance activities of SAMHD1. Exp Hematol 2017; 52:32-39. [PMID: 28502830 DOI: 10.1016/j.exphem.2017.05.001] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Revised: 04/29/2017] [Accepted: 05/02/2017] [Indexed: 01/04/2023]
Abstract
Sterile alpha motif and histidine/aspartic acid domain-containing protein 1 (SAMHD1) is a (deoxy)guanosine triphosphate (dGTP/GTP)-activated deoxyribonucleoside triphosphate (dNTP) triphosphohydrolase involved in cellular dNTP homoeostasis. Mutations in SAMHD1 have been associated with the hyperinflammatory disease Aicardi-Goutières syndrome (AGS). SAMHD1 also limits cells' permissiveness to infection with diverse viruses, including human immunodeficiency virus (HIV-1), and controls endogenous retroviruses. Increasing evidence supports the role of SAMHD1 as a tumor suppressor. However, SAMHD1 also can act as a resistance factor to nucleoside-based chemotherapies by hydrolyzing their active triphosphate metabolites, thereby reducing response of various malignancies to these anticancer drugs. Hence, informed cancer therapies must take into account the ambiguous properties of SAMHD1 as both an inhibitor of uncontrolled proliferation and a resistance factor limiting the efficacy of anticancer treatments. Here, we provide evidence that SAMHD1 is a double-edged sword for patients with acute myelogenous leukemia (AML). Our time-dependent analyses of The Cancer Genome Atlas (TCGA) AML cohort indicate that high expression of SAMHD1, even though it critically limits the efficacy of high-dose ara-C therapy, might be associated with more favorable disease progression.
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Affiliation(s)
- Nikolas Herold
- Childhood Cancer Research Unit, Department of Women's and Children's Health, Karolinska Institutet, and Karolinska University Hospital, Stockholm, Sweden; Theme of Children's and Women's Health, Astrid Lindgren Children's Hospital, Karolinska University Hospital, Stockholm, Sweden.
| | - Sean G Rudd
- Science for Life Laboratory, Division of Translational Medicine and Chemical Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Kumar Sanjiv
- Science for Life Laboratory, Division of Translational Medicine and Chemical Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Juliane Kutzner
- Department of Infectious Diseases, Virology, University Hospital Heidelberg, Heidelberg, Germany
| | - Ida Hed Myrberg
- Childhood Cancer Research Unit, Department of Women's and Children's Health, Karolinska Institutet, and Karolinska University Hospital, Stockholm, Sweden
| | - Cynthia B J Paulin
- Science for Life Laboratory, Division of Translational Medicine and Chemical Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Thale Kristin Olsen
- Childhood Cancer Research Unit, Department of Women's and Children's Health, Karolinska Institutet, and Karolinska University Hospital, Stockholm, Sweden
| | - Thomas Helleday
- Science for Life Laboratory, Division of Translational Medicine and Chemical Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Jan-Inge Henter
- Childhood Cancer Research Unit, Department of Women's and Children's Health, Karolinska Institutet, and Karolinska University Hospital, Stockholm, Sweden; Theme of Children's and Women's Health, Astrid Lindgren Children's Hospital, Karolinska University Hospital, Stockholm, Sweden
| | - Torsten Schaller
- Department of Infectious Diseases, Virology, University Hospital Heidelberg, Heidelberg, Germany.
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49
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Li M, Zhang D, Zhu M, Shen Y, Wei W, Ying S, Korner H, Li J. Roles of SAMHD1 in antiviral defense, autoimmunity and cancer. Rev Med Virol 2017; 27. [PMID: 28444859 DOI: 10.1002/rmv.1931] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2016] [Revised: 02/26/2017] [Accepted: 03/13/2017] [Indexed: 01/02/2023]
Abstract
The enzyme, sterile α motif and histidine-aspartic acid domain-containing protein 1 (SAMHD1) diminishes infection of human immunodeficiency virus type 1 (HIV-1) by hydrolyzing intracellular deoxynucleotide triphosphates (dNTPs) in myeloid cells and resting CD4+ T cells. This dNTP degradation reduces the dNTP concentration to a level insufficient for viral cDNA synthesis, thereby inhibiting retroviral replication. This antiviral enzymatic activity can be inhibited by viral protein X (Vpx). The HIV-2/SIV Vpx causes degradation of SAMHD1, thus interfering with the SAMHD1-mediated restriction of retroviral replication. Recently, SAMHD1 has been suggested to restrict HIV-1 infection by directly digesting genomic HIV-1 RNA through a still controversial RNase activity. Here, we summarize the current knowledge about structure, antiviral mechanisms, intracellular localization, interferon-regulated expression of SAMHD1. We also describe SAMHD1-deficient animal models and an antiviral drug on the basis of disrupting proteasomal degradation of SAMHD1. In addition, the possible roles of SAMHD1 in regulating innate immune sensing, Aicardi-Goutières syndrome and cancer are discussed in this review.
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Affiliation(s)
- Miaomiao Li
- Department of Immunology, School of Basic Medical Sciences, Anhui Medical University, Hefei, Anhui Province, PR China
| | - Dong Zhang
- Department of Immunology, School of Basic Medical Sciences, Anhui Medical University, Hefei, Anhui Province, PR China.,School of Basic Medical Sciences and Biopharmaceutical Research Institute, Anhui Medical University, Hefei, Anhui Province, PR China
| | - Mengying Zhu
- Department of Immunology, School of Basic Medical Sciences, Anhui Medical University, Hefei, Anhui Province, PR China
| | - Yuxian Shen
- School of Basic Medical Sciences and Biopharmaceutical Research Institute, Anhui Medical University, Hefei, Anhui Province, PR China
| | - Wei Wei
- Institute of Clinical Pharmacology, Anhui Medical University, Key Laboratory of Anti-inflammatory and Immune Medicine, Ministry of Education, Hefei, Anhui Province, PR China
| | - Songcheng Ying
- Department of Immunology, School of Basic Medical Sciences, Anhui Medical University, Hefei, Anhui Province, PR China.,School of Pharmacy, Anhui Medical University, Hefei, Anhui Province, PR China
| | - Heinrich Korner
- Institute of Clinical Pharmacology, Anhui Medical University, Key Laboratory of Anti-inflammatory and Immune Medicine, Ministry of Education, Hefei, Anhui Province, PR China.,Menzies Institute for Medical Research Tasmania, Hobart, Tasmania, Australia
| | - Jun Li
- School of Pharmacy, Anhui Medical University, Hefei, Anhui Province, PR China
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50
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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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