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Lopez A, Nichols Doyle R, Sandoval C, Nisson K, Yang V, Fregoso OI. Viral Modulation of the DNA Damage Response and Innate Immunity: Two Sides of the Same Coin. J Mol Biol 2022; 434:167327. [PMID: 34695379 PMCID: PMC9119581 DOI: 10.1016/j.jmb.2021.167327] [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: 09/01/2021] [Revised: 10/16/2021] [Accepted: 10/18/2021] [Indexed: 11/29/2022]
Abstract
The DDR consists of multiple pathways that sense, signal, and respond to anomalous DNA. To promote efficient replication, viruses have evolved to engage and even modulate the DDR. In this review, we will discuss a select set of diverse viruses and the range of mechanisms they evolved to interact with the DDR and some of the subsequent cellular consequences. There is a dichotomy in that the DDR can be both beneficial for viruses yet antiviral. We will also review the connection between the DDR and innate immunity. Previously believed to be disparate cellular functions, more recent research is emerging that links these processes. Furthermore, we will discuss some discrepancies in the literature that we propose can be remedied by utilizing more consistent DDR-focused assays. By doing so, we hope to obtain a much clearer understanding of how broadly these mechanisms and phenotypes are conserved among all viruses. This is crucial for human health since understanding how viruses manipulate the DDR presents an important and tractable target for antiviral therapies.
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Affiliation(s)
- Andrew Lopez
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, CA, USA; Molecular Biology Institute, University of California, Los Angeles, CA, USA
| | - Randilea Nichols Doyle
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, CA, USA
| | - Carina Sandoval
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, CA, USA; Molecular Biology Institute, University of California, Los Angeles, CA, USA
| | - Karly Nisson
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, CA, USA; Molecular Biology Institute, University of California, Los Angeles, CA, USA
| | - Vivian Yang
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, CA, USA; Molecular Biology Institute, University of California, Los Angeles, CA, USA
| | - Oliver I Fregoso
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, CA, USA; Molecular Biology Institute, University of California, Los Angeles, CA, USA.
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2
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Dual roles of SAMHD1 in tumor development and chemoresistance to anticancer drugs. Oncol Lett 2021; 21:451. [PMID: 33907561 PMCID: PMC8063254 DOI: 10.3892/ol.2021.12712] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Accepted: 03/10/2021] [Indexed: 11/05/2022] Open
Abstract
Human sterile alpha motif and HD-domain-containing protein 1 (SAMHD1) has been identified as a GTP or dGTP-dependent deoxynucleotide triphosphohydrolase (dNTPase) and acts as an antiviral factor against certain retroviruses and DNA viruses. Genetic mutation in SAMHD1 causes the inflammatory Aicardi-Goutières Syndrome and abnormal intracellular deoxyribonucleoside triphosphates (dNTPs) pool. At present, the role of SAMHD1 in numerous types of cancer, such as chronic lymphocytic leukemia, lung cancer and colorectal cancer, is highly studied. Furthermore, it has been found that methylation, acetylation and phosphorylation are involved in the regulation of SAMHD1 expression, and that genetic mutations can cause changes in its activities, including dNTPase activity, long interspersed element type 1 (LINE-1) suppression and DNA damage repair, which could lead to uncontrolled cell cycle progression and cancer development. In addition, SAMHD1 has been reported to have a negative regulatory role in the chemosensitivity to anticancer drugs through its dNTPase activity. The present review aimed to summarize the regulation of SAMHD1 expression in cancer and its function in tumor growth and chemotherapy sensitivity, and discussed controversial points and future directions.
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Aquaro S, Borrajo A, Pellegrino M, Svicher V. Mechanisms underlying of antiretroviral drugs in different cellular reservoirs with a focus on macrophages. Virulence 2021; 11:400-413. [PMID: 32375558 PMCID: PMC7219522 DOI: 10.1080/21505594.2020.1760443] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Ongoing with current combinations of antiretroviral drugs for the treatment of Human Immunodeficiency Virus (HIV) infection can successfully maintain long-term suppression of HIV-1 replication in plasma. Still, none of these therapies is capable of extinguishing the virus from the long-lived cellular reservoir, including monocyte-derived macrophages (MDM), that means the principal obstacle to HIV cure. MDM are widely distributed in all tissues and organs, including central system nervous (CNS) where they represent the most frequent HIV-infected cells that means the principal obstacle to HIV cure. Current FDA-approved antiretroviral drugs target viral reverse transcriptase, protease, integrase, and entry processes (coreceptor or fusion blockade). It is desirable to continue to develop new antiretrovirals directed against alternative targets in the virus lifecycle in order to further optimize therapeutic options, overcome resistance to existing medications, and potentially contribute to the elimination of viral reservoirs.This review provides a comprehensive overview of the activity of antiretroviral drugs (classical and upcoming) in monocytes-derived macrophages (MDM). Defining the antiviral activity of these drugs in this important cellular HIV-1 reservoir provides crucial hints about their efficacy in HIV-1 infected patients.
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Affiliation(s)
- Stefano Aquaro
- Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, Rende, Italy
| | - Ana Borrajo
- Department of Experimental Medicine, University of Rome Tor Vergata, Roma, Italy.,Department of Microbiology and Parasitology, Faculty of Pharmacy, Complutense University of Madrid, Madrid, Spain
| | - Michele Pellegrino
- Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, Rende, Italy
| | - Valentina Svicher
- Department of Experimental Medicine, University of Rome Tor Vergata, Roma, Italy
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Posch W, Bermejo-Jambrina M, Lass-Flörl C, Wilflingseder D. Role of Complement Receptors (CRs) on DCs in Anti-HIV-1 Immunity. Front Immunol 2020; 11:572114. [PMID: 33224139 PMCID: PMC7670068 DOI: 10.3389/fimmu.2020.572114] [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: 06/12/2020] [Accepted: 10/06/2020] [Indexed: 12/12/2022] Open
Abstract
Upon entry of human immunodeficiency virus 1 (HIV-1) into the host, innate immune mechanisms are acting as a first line of defense, that considerably also modify adaptive immunity by the provision of specific signals. Innate and adaptive immune responses are intimately linked and dendritic cells (DCs) together with complement (C) play an important role in regulation of adaptive immunity. Initially, the role of complement was considered to primarily support – or COMPLEMENT - cytolytic actions of antibodies or antibody-complexed antigens (immune complexes, ICs) or directly kill the pathogens by complement-mediated lysis. Recently, the role of complement was revised and found to significantly augmenting and modulating adaptive immunity, in particular against viruses. Complement and DCs are therefore predestined to open novel avenues for antiviral research and potential therapeutic interventions. Recent studies on interactions of complement-opsonized HIV-1 with DCs demonstrated a high potential of such primed DCs to initiate efficient antiviral and cytotoxic anti-HIV-1 immunity and complement-coated viral particles shift DCs functions via CR3 and CR4 in an antithetic manner. This review will focus on our current knowledge of CR3 and CR4 actions on DCs during HIV-1 binding and the outcome of infection influenced by entry and signaling pathways.
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Affiliation(s)
- Wilfried Posch
- Institute of Hygiene and Medical Microbiology, Medical University of Innsbruck, Innsbruck, Austria
| | - Marta Bermejo-Jambrina
- Institute of Hygiene and Medical Microbiology, Medical University of Innsbruck, Innsbruck, Austria.,Department of Experimental Immunology, Amsterdam Infection and Immunity Institute, Academic Medical Center, University of Amsterdam, Amsterdam, Netherlands
| | - Cornelia Lass-Flörl
- Institute of Hygiene and Medical Microbiology, Medical University of Innsbruck, Innsbruck, Austria
| | - Doris Wilflingseder
- Institute of Hygiene and Medical Microbiology, Medical University of Innsbruck, Innsbruck, Austria
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5
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Ferreira IATM, Porterfield JZ, Gupta RK, Mlcochova P. Cell Cycle Regulation in Macrophages and Susceptibility to HIV-1. Viruses 2020; 12:v12080839. [PMID: 32751972 PMCID: PMC7472357 DOI: 10.3390/v12080839] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2020] [Revised: 07/24/2020] [Accepted: 07/28/2020] [Indexed: 02/07/2023] Open
Abstract
Macrophages are the first line of defence against invading pathogens. They play a crucial role in immunity but also in regeneration and homeostasis. Their remarkable plasticity in their phenotypes and function provides them with the ability to quickly respond to environmental changes and infection. Recent work shows that macrophages undergo cell cycle transition from a G0/terminally differentiated state to a G1 state. This G0-to-G1 transition presents a window of opportunity for HIV-1 infection. Macrophages are an important target for HIV-1 but express high levels of the deoxynucleotide-triphosphate hydrolase SAMHD1, which restricts viral DNA synthesis by decreasing levels of dNTPs. While the G0 state is non-permissive to HIV-1 infection, a G1 state is very permissive to HIV-1 infection. This is because macrophages in a G1 state switch off the antiviral restriction factor SAMHD1 by phosphorylation, thereby allowing productive HIV-1 infection. Here, we explore the macrophage cell cycle and the interplay between its regulation and permissivity to HIV-1 infection.
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Affiliation(s)
- Isabella A. T. M. Ferreira
- Cambridge Institute of Therapeutic Immunology & Infectious Disease (CITIID), Cambridge CB20AW, UK; (I.A.T.M.F.); (R.K.G.)
- Department of Medicine, University of Cambridge, Cambridge CB20QQ, UK
| | - J. Zachary Porterfield
- Department of Microbiology, University of Kentucky, Lexington, KY 40536, USA;
- Africa Health Research Institute, Durban 4001, South Africa
| | - Ravindra K. Gupta
- Cambridge Institute of Therapeutic Immunology & Infectious Disease (CITIID), Cambridge CB20AW, UK; (I.A.T.M.F.); (R.K.G.)
- Department of Medicine, University of Cambridge, Cambridge CB20QQ, UK
- Africa Health Research Institute, Durban 4001, South Africa
| | - Petra Mlcochova
- Cambridge Institute of Therapeutic Immunology & Infectious Disease (CITIID), Cambridge CB20AW, UK; (I.A.T.M.F.); (R.K.G.)
- Department of Medicine, University of Cambridge, Cambridge CB20QQ, UK
- Correspondence:
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Gupta RK, Peppa D, Hill AL, Gálvez C, Salgado M, Pace M, McCoy LE, Griffith SA, Thornhill J, Alrubayyi A, Huyveneers LEP, Nastouli E, Grant P, Edwards SG, Innes AJ, Frater J, Nijhuis M, Wensing AMJ, Martinez-Picado J, Olavarria E. Evidence for HIV-1 cure after CCR5Δ32/Δ32 allogeneic haemopoietic stem-cell transplantation 30 months post analytical treatment interruption: a case report. Lancet HIV 2020; 7:e340-e347. [PMID: 32169158 PMCID: PMC7606918 DOI: 10.1016/s2352-3018(20)30069-2] [Citation(s) in RCA: 121] [Impact Index Per Article: 30.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 02/17/2020] [Accepted: 02/19/2020] [Indexed: 12/20/2022]
Abstract
BACKGROUND The London patient (participant 36 in the IciStem cohort) underwent allogeneic stem-cell transplantation with cells that did not express CCR5 (CCR5Δ32/Δ32); remission was reported at 18 months after analytical treatment interruption (ATI). Here, we present longer term data for this patient (up to 30 months after ATI), including sampling from diverse HIV-1 reservoir sites. METHODS We used ultrasensitive viral load assays of plasma, semen, and cerebrospinal fluid (CSF) samples to detect HIV-1 RNA. In gut biopsy samples and lymph-node tissue, cell-copy number and total HIV-1 DNA levels were quantified in multiple replicates, using droplet digital PCR (ddPCR) and quantitative real-time PCR. We also analysed the presence of intact proviral DNA using multiplex ddPCR targeting the packaging signal (ψ) and envelope (env). We did intracellular cytokine staining to measure HIV-1-specific T-cell responses. We used low-sensitive and low-avidity antibody assays to measure the humoral response to HIV-1. We predicted the probability of rebound using a mathematical model and inference approach. FINDINGS HIV-1 viral load in plasma remained undetectable in the London patient up to 30 months (last tested on March 4, 2020), using an assay with a detection limit of 1 copy per mL. The patient's CD4 count was 430 cells per μL (23·5% of total T cells) at 28 months. A very low-level positive signal for HIV-1 DNA was recorded in peripheral CD4 memory cells at 28 months. The viral load in semen was undetectable in both plasma (lower limit of detection [LLD] <12 copies per mL) and cells (LLD 10 copies per 106 cells) at 21 months. CSF was within normal parameters at 25 months, with HIV-1 RNA below the detection limit (LLD 1 copy per mL). HIV-1 DNA by ddPCR was negative in rectum, caecum, and sigmoid colon and terminal ileum tissue samples at 22 months. Lymph-node tissue from axilla was positive for the long-terminal repeat (33 copies per 106 cells) and env (26·1 copies per 106 cells), negative for ψ and integrase, and negative by the intact proviral DNA assay, at 27 months. HIV-1-specific CD4 and CD8 T-cell responses have remained absent at 27 months. Low-avidity Env antibodies have continued to decline. Mathematical modelling suggests that the probability of remission for life (cure) is 98% in the context of 80% donor chimerism in total HIV target cells and greater than 99% probability of remission for life with 90% donor chimerism. INTERPRETATION The London patient has been in HIV-1 remission for 30 months with no detectable replication-competent virus in blood, CSF, intestinal tissue, or lymphoid tissue. Donor chimerism has been maintained at 99% in peripheral T cells. We propose that these findings represent HIV-1 cure. FUNDING Wellcome Trust and amfAR (American Foundation for AIDS Research).
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Affiliation(s)
- Ravindra Kumar Gupta
- Department of Medicine, University of Cambridge, Cambridge, UK; Africa Health Research Institute, Durban, South Africa.
| | - Dimitra Peppa
- Nuffield Department of Medicine, University of Oxford, Oxford, UK; Population, Policy and Practice, UCL Great Ormond Street Institute of Child Health, London, UK
| | - Alison L Hill
- Department for Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA
| | - Cristina Gálvez
- IrsiCaixa AIDS Research Institute, Badalona, Spain; Autonomous University of Barcelona, Cerdanyola del Vallès, Spain
| | | | - Matthew Pace
- Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Laura E McCoy
- Division of Infection and Immunity, University College London (UCL), London, UK
| | - Sarah A Griffith
- Division of Infection and Immunity, University College London (UCL), London, UK
| | | | | | - Laura E P Huyveneers
- Department of Medical Microbiology, University Medical Center, Utrecht, Netherlands
| | - Eleni Nastouli
- Division of Infection and Immunity, University College London (UCL), London, UK; Department of Virology, UCL Hospitals, London, UK; Population, Policy and Practice, UCL Great Ormond Street Institute of Child Health, London, UK
| | - Paul Grant
- Department of Virology, UCL Hospitals, London, UK
| | - Simon G Edwards
- Mortimer Market Centre, Department of HIV, Central and North West London NHS Trust, London, UK
| | - Andrew J Innes
- Imperial College London, London, UK; Imperial College NHS Healthcare Trust, Hammersmith Hospital, London, UK
| | - John Frater
- Nuffield Department of Medicine, University of Oxford, Oxford, UK; Oxford National Institute for Health Research Biomedical Research Centre, Oxford, UK
| | - Monique Nijhuis
- Department of Medical Microbiology, University Medical Center, Utrecht, Netherlands
| | - Anne Marie J Wensing
- Department of Medical Microbiology, University Medical Center, Utrecht, Netherlands
| | - Javier Martinez-Picado
- IrsiCaixa AIDS Research Institute, Badalona, Spain; University of Vic - Central University of Catalonia, Vic, Spain; Catalan Institution for Research and Advanced Studies, Barcelona, Spain
| | - Eduardo Olavarria
- Imperial College London, London, UK; Mortimer Market Centre, Department of HIV, Central and North West London NHS Trust, London, UK
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7
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Yin X, Langer S, Zhang Z, Herbert KM, Yoh S, König R, Chanda SK. Sensor Sensibility-HIV-1 and the Innate Immune Response. Cells 2020; 9:E254. [PMID: 31968566 PMCID: PMC7016969 DOI: 10.3390/cells9010254] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 01/14/2020] [Accepted: 01/15/2020] [Indexed: 02/07/2023] Open
Abstract
Innate immunity represents the human immune system's first line of defense against a pathogenic intruder and is initiated by the recognition of conserved molecular structures known as pathogen-associated molecular patterns (PAMPs) by specialized cellular sensors, called pattern recognition receptors (PRRs). Human immunodeficiency virus type 1 (HIV-1) is a unique human RNA virus that causes acquired immunodeficiency syndrome (AIDS) in infected individuals. During the replication cycle, HIV-1 undergoes reverse transcription of its RNA genome and integrates the resulting DNA into the human genome. Subsequently, transcription of the integrated provirus results in production of new virions and spreading infection of the virus. Throughout the viral replication cycle, numerous nucleic acid derived PAMPs can be recognized by a diverse set of innate immune sensors in infected cells. However, HIV-1 has evolved efficient strategies to evade or counteract this immune surveillance and the downstream responses. Understanding the molecular underpinnings of the concerted actions of the innate immune system, as well as the corresponding viral evasion mechanisms during infection, is critical to understanding HIV-1 transmission and pathogenesis, and may provide important guidance for the design of appropriate adjuvant and vaccine strategies. Here, we summarize current knowledge of the molecular basis for sensing HIV-1 in human cells, including CD4+ T cells, dendritic cells, and macrophages. Furthermore, we discuss the underlying mechanisms by which innate sensing is regulated, and describe the strategies developed by HIV-1 to evade sensing and immune responses.
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Affiliation(s)
- Xin Yin
- Immunity and Pathogenesis Program, Infectious and Inflammatory Disease Center, Sanford Burnham Prebys Medical Discovery Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA; (X.Y.); (S.L.); (Z.Z.); (K.M.H.); (S.Y.); (R.K.)
| | - Simon Langer
- Immunity and Pathogenesis Program, Infectious and Inflammatory Disease Center, Sanford Burnham Prebys Medical Discovery Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA; (X.Y.); (S.L.); (Z.Z.); (K.M.H.); (S.Y.); (R.K.)
- Boehringer Ingelheim Pharma GmbH & Co. KG, 55216 Ingelheim am Rhein, Germany
| | - Zeli Zhang
- Immunity and Pathogenesis Program, Infectious and Inflammatory Disease Center, Sanford Burnham Prebys Medical Discovery Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA; (X.Y.); (S.L.); (Z.Z.); (K.M.H.); (S.Y.); (R.K.)
- Division of Vaccine Discovery, La Jolla Institute for Immunology, 9420 Athena Cir, La Jolla, CA 92037, USA
| | - Kristina M. Herbert
- Immunity and Pathogenesis Program, Infectious and Inflammatory Disease Center, Sanford Burnham Prebys Medical Discovery Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA; (X.Y.); (S.L.); (Z.Z.); (K.M.H.); (S.Y.); (R.K.)
| | - Sunnie Yoh
- Immunity and Pathogenesis Program, Infectious and Inflammatory Disease Center, Sanford Burnham Prebys Medical Discovery Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA; (X.Y.); (S.L.); (Z.Z.); (K.M.H.); (S.Y.); (R.K.)
| | - Renate König
- Immunity and Pathogenesis Program, Infectious and Inflammatory Disease Center, Sanford Burnham Prebys Medical Discovery Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA; (X.Y.); (S.L.); (Z.Z.); (K.M.H.); (S.Y.); (R.K.)
- Host-Pathogen Interactions, Paul-Ehrlich-Institut, 63225 Langen, Germany
| | - Sumit K. Chanda
- Immunity and Pathogenesis Program, Infectious and Inflammatory Disease Center, Sanford Burnham Prebys Medical Discovery Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA; (X.Y.); (S.L.); (Z.Z.); (K.M.H.); (S.Y.); (R.K.)
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Interplay between Intrinsic and Innate Immunity during HIV Infection. Cells 2019; 8:cells8080922. [PMID: 31426525 PMCID: PMC6721663 DOI: 10.3390/cells8080922] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Revised: 08/13/2019] [Accepted: 08/15/2019] [Indexed: 02/06/2023] Open
Abstract
Restriction factors are antiviral components of intrinsic immunity which constitute a first line of defense by blocking different steps of the human immunodeficiency virus (HIV) replication cycle. In immune cells, HIV infection is also sensed by several pattern recognition receptors (PRRs), leading to type I interferon (IFN-I) and inflammatory cytokines production that upregulate antiviral interferon-stimulated genes (ISGs). Several studies suggest a link between these two types of immunity. Indeed, restriction factors, that are generally interferon-inducible, are able to modulate immune responses. This review highlights recent knowledge of the interplay between restriction factors and immunity inducing antiviral defenses. Counteraction of this intrinsic and innate immunity by HIV viral proteins will also be discussed.
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D Urbano V, De Crignis E, Re MC. Host Restriction Factors and Human Immunodeficiency Virus (HIV-1): A Dynamic Interplay Involving All Phases of the Viral Life Cycle. Curr HIV Res 2019; 16:184-207. [PMID: 30117396 DOI: 10.2174/1570162x16666180817115830] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2018] [Revised: 07/31/2018] [Accepted: 08/09/2018] [Indexed: 02/08/2023]
Abstract
Mammalian cells have evolved several mechanisms to prevent or block lentiviral infection and spread. Among the innate immune mechanisms, the signaling cascade triggered by type I interferon (IFN) plays a pivotal role in limiting the burden of HIV-1. In the presence of IFN, human cells upregulate the expression of a number of genes, referred to as IFN-stimulated genes (ISGs), many of them acting as antiviral restriction factors (RFs). RFs are dominant proteins that target different essential steps of the viral cycle, thereby providing an early line of defense against the virus. The identification and characterization of RFs have provided unique insights into the molecular biology of HIV-1, further revealing the complex host-pathogen interplay that characterizes the infection. The presence of RFs drove viral evolution, forcing the virus to develop specific proteins to counteract their activity. The knowledge of the mechanisms that prevent viral infection and their viral counterparts may offer new insights to improve current antiviral strategies. This review provides an overview of the RFs targeting HIV-1 replication and the mechanisms that regulate their expression as well as their impact on viral replication and the clinical course of the disease.
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Affiliation(s)
- Vanessa D Urbano
- Retrovirus Laboratory, Operative Unit of Clinical Microbiology, S. Orsola-Malpighi University Hospital, Bologna, Italy
| | - Elisa De Crignis
- Retrovirus Laboratory, Operative Unit of Clinical Microbiology, S. Orsola-Malpighi University Hospital, Bologna, Italy
| | - Maria Carla Re
- Retrovirus Laboratory, Operative Unit of Clinical Microbiology, S. Orsola-Malpighi University Hospital, Bologna, Italy
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Expression of MDM2 in Macrophages Promotes the Early Postentry Steps of HIV-1 Infection through Inhibition of p53. J Virol 2019; 93:JVI.01871-18. [PMID: 30674627 DOI: 10.1128/jvi.01871-18] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Accepted: 01/13/2019] [Indexed: 12/19/2022] Open
Abstract
The molecular basis for HIV-1 susceptibility in primary human monocyte-derived macrophages (MDMs) was previously evaluated by comparing the transcriptome of infected and bystander populations. Careful analysis of the data suggested that the ubiquitin ligase MDM2 acted as a positive regulator of HIV-1 replication in MDMs. In this study, MDM2 silencing through transcript-specific small interfering RNAs in MDMs induced a reduction in HIV-1 reverse transcription and integration along with an increase in the expression of p53-induced genes, including CDKN1A Experiments with Nutlin-3, a pharmacological inhibitor of MDM2 p53-binding activity, showed a similar effect on HIV-1 infection, suggesting that the observed restriction in HIV-1 production results from the release/activation of p53 and not the absence of MDM2 per se Knockdown and inhibition of MDM2 also both correlate with a decrease in the Thr592-phosphorylated inactive form of SAMHD1. The expression level of MDM2 and the p53 activation status are therefore important factors in the overall susceptibility of macrophages to HIV-1 infection, bringing a new understanding of signaling events controlling the process of virus replication in this cell type.IMPORTANCE Macrophages, with their long life span in vivo and their resistance to HIV-1-mediated cytopathic effect, might serve as viral reservoirs, contributing to virus persistence in an infected individual. Identification of host factors that increase the overall susceptibility of macrophages to HIV-1 might provide new therapeutic targets for the efficient control of viral replication in these cells and limit the formation of reservoirs in exposed individuals. In this study, we demonstrate the importance of p53 regulation by MDM2, which creates a cellular environment more favorable to the early steps of HIV-1 replication. Moreover, we show that p53 stabilization reduces virus infection in human macrophages, highlighting the important role of p53 in antiviral immunity.
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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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