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Levesque S, Cosentino A, Verma A, Genovese P, Bauer DE. Enhancing prime editing in hematopoietic stem and progenitor cells by modulating nucleotide metabolism. Nat Biotechnol 2024:10.1038/s41587-024-02266-4. [PMID: 38806736 DOI: 10.1038/s41587-024-02266-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Accepted: 04/26/2024] [Indexed: 05/30/2024]
Abstract
Therapeutic prime editing of hematopoietic stem and progenitor cells (HSPCs) holds great potential to remedy blood disorders. Quiescent cells have low nucleotide levels and resist retroviral infection, and it is possible that nucleotide metabolism could limit reverse transcription-mediated prime editing in HSPCs. We demonstrate that deoxynucleoside supplementation and Vpx-mediated degradation of SAMHD1 improve prime editing efficiency in HSPCs, especially when coupled with editing approaches that evade mismatch repair.
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Affiliation(s)
- Sébastien Levesque
- Division of Hematology/Oncology, Boston Children's Hospital, Boston, MA, USA
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
- Harvard Stem Cell Institute, Cambridge, MA, USA
- Broad Institute, Cambridge, MA, USA
- Department of Pediatrics, Harvard Medical School, Boston, MA, USA
| | - Andrea Cosentino
- Division of Hematology/Oncology, Boston Children's Hospital, Boston, MA, USA
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
- Department of Pediatrics, Harvard Medical School, Boston, MA, USA
- Milano-Bicocca University, Milan, Italy
| | - Archana Verma
- Division of Hematology/Oncology, Boston Children's Hospital, Boston, MA, USA
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
- Harvard Stem Cell Institute, Cambridge, MA, USA
- Broad Institute, Cambridge, MA, USA
- Department of Pediatrics, Harvard Medical School, Boston, MA, USA
| | - Pietro Genovese
- Division of Hematology/Oncology, Boston Children's Hospital, Boston, MA, USA
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
- Harvard Stem Cell Institute, Cambridge, MA, USA
- Broad Institute, Cambridge, MA, USA
- Department of Pediatrics, Harvard Medical School, Boston, MA, USA
| | - Daniel E Bauer
- Division of Hematology/Oncology, Boston Children's Hospital, Boston, MA, USA.
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA, USA.
- Harvard Stem Cell Institute, Cambridge, MA, USA.
- Broad Institute, Cambridge, MA, USA.
- Department of Pediatrics, Harvard Medical School, Boston, MA, USA.
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2
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O’Connor PBF, Mahony J, Casey E, Baranov PV, van Sinderen D, Yordanova MM. Ribosome profiling reveals downregulation of UMP biosynthesis as the major early response to phage infection. Microbiol Spectr 2024; 12:e0398923. [PMID: 38451091 PMCID: PMC10986495 DOI: 10.1128/spectrum.03989-23] [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: 11/23/2023] [Accepted: 02/14/2024] [Indexed: 03/08/2024] Open
Abstract
Bacteria have evolved diverse defense mechanisms to counter bacteriophage attacks. Genetic programs activated upon infection characterize phage-host molecular interactions and ultimately determine the outcome of the infection. In this study, we applied ribosome profiling to monitor protein synthesis during the early stages of sk1 bacteriophage infection in Lactococcus cremoris. Our analysis revealed major changes in gene expression within 5 minutes of sk1 infection. Notably, we observed a specific and severe downregulation of several pyr operons which encode enzymes required for uridine monophosphate biosynthesis. Consistent with previous findings, this is likely an attempt of the host to starve the phage of nucleotides it requires for propagation. We also observed a gene expression response that we expect to benefit the phage. This included the upregulation of 40 ribosome proteins that likely increased the host's translational capacity, concurrent with a downregulation of genes that promote translational fidelity (lepA and raiA). In addition to the characterization of host-phage gene expression responses, the obtained ribosome profiling data enabled us to identify two putative recoding events as well as dozens of loci currently annotated as pseudogenes that are actively translated. Furthermore, our study elucidated alterations in the dynamics of the translation process, as indicated by time-dependent changes in the metagene profile, suggesting global shifts in translation rates upon infection. Additionally, we observed consistent modifications in the ribosome profiles of individual genes, which were apparent as early as 2 minutes post-infection. The study emphasizes our ability to capture rapid alterations of gene expression during phage infection through ribosome profiling. IMPORTANCE The ribosome profiling technology has provided invaluable insights for understanding cellular translation and eukaryotic viral infections. However, its potential for investigating host-phage interactions remains largely untapped. Here, we applied ribosome profiling to Lactococcus cremoris cultures infected with sk1, a major infectious agent in dairy fermentation processes. This revealed a profound downregulation of genes involved in pyrimidine nucleotide synthesis at an early stage of phage infection, suggesting an anti-phage program aimed at restricting nucleotide availability and, consequently, phage propagation. This is consistent with recent findings and contributes to our growing appreciation for the role of nucleotide limitation as an anti-viral strategy. In addition to capturing rapid alterations in gene expression levels, we identified translation occurring outside annotated regions, as well as signatures of non-standard translation mechanisms. The gene profiles revealed specific changes in ribosomal densities upon infection, reflecting alterations in the dynamics of the translation process.
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Affiliation(s)
- Patrick B. F. O’Connor
- School of Biochemistry and Cell Biology, University College Cork, Cork, Ireland
- EIRNA Bio, Bioinnovation Hub, Cork, Ireland
| | - Jennifer Mahony
- School of Microbiology and APC Microbiome Ireland, University College Cork, Cork, Ireland
| | - Eoghan Casey
- School of Microbiology and APC Microbiome Ireland, University College Cork, Cork, Ireland
| | - Pavel V. Baranov
- School of Biochemistry and Cell Biology, University College Cork, Cork, Ireland
| | - Douwe van Sinderen
- School of Microbiology and APC Microbiome Ireland, University College Cork, Cork, Ireland
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3
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Cheng R, Huang F, Lu X, Yan Y, Yu B, Wang X, Zhu B. Prokaryotic Gabija complex senses and executes nucleotide depletion and DNA cleavage for antiviral defense. Cell Host Microbe 2023; 31:1331-1344.e5. [PMID: 37480847 DOI: 10.1016/j.chom.2023.06.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 05/03/2023] [Accepted: 06/27/2023] [Indexed: 07/24/2023]
Abstract
The Gabija complex is a prokaryotic antiviral system consisting of the GajA and GajB proteins. GajA was identified as a DNA nicking endonuclease but the functions of GajB and the complex remain unknown. Here, we show that synergy between GajA-mediated DNA cleavage and nucleotide hydrolysis by GajB initiates efficient abortive infection defense against virulent bacteriophages. The antiviral activity of GajA requires GajB, which senses DNA termini produced by GajA to hydrolyze (d)A/(d)GTP, depleting essential nucleotides. This ATPase activity of Gabija complex is only activated upon DNA binding. GajA binds to GajB to form stable complexes in vivo and in vitro. However, a functional Gabija complex requires a molecular ratio between GajB and GajA below 1:1, indicating stoichiometric regulation of the DNA/nucleotide processing complex. Thus, the Gabija system exhibits distinct and efficient antiviral defense through sequential sensing and activation of nucleotide depletion and DNA cleavage, causing a cascade suicide effect.
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Affiliation(s)
- Rui Cheng
- Key Laboratory of Molecular Biophysics, the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China.
| | - Fengtao Huang
- Key Laboratory of Molecular Biophysics, the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China; Shenzhen Huazhong University of Science and Technology Research Institute, Shenzhen 518063, China
| | - Xueling Lu
- Key Laboratory of Molecular Biophysics, the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Yan Yan
- Key Laboratory of Molecular Biophysics, the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Bingbing Yu
- Key Laboratory of Molecular Biophysics, the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Xionglue Wang
- Key Laboratory of Molecular Biophysics, the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Bin Zhu
- Key Laboratory of Molecular Biophysics, the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China; Shenzhen Huazhong University of Science and Technology Research Institute, Shenzhen 518063, China.
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Chvatal-Medina M, Lopez-Guzman C, Diaz FJ, Gallego S, Rugeles MT, Taborda NA. Molecular mechanisms by which the HIV-1 latent reservoir is established and therapeutic strategies for its elimination. Arch Virol 2023; 168:218. [PMID: 37530901 DOI: 10.1007/s00705-023-05800-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Accepted: 04/12/2023] [Indexed: 08/03/2023]
Abstract
The human immunodeficiency virus type 1 (HIV-1) reservoir, composed of cells harboring the latent, integrated virus, is not eliminated by antiretroviral therapy. It therefore represents a significant barrier to curing the infection. The biology of HIV-1 reservoirs, the mechanisms of their persistence, and effective strategies for their eradication are not entirely understood. Here, we review the molecular mechanisms by which HIV-1 reservoirs develop, the cells and compartments where the latent virus resides, and advancements in curative therapeutic strategies. We first introduce statistics and relevant data on HIV-1 infection, aspects of pathogenesis, the role of antiretroviral therapy, and the general features of the latent HIV reservoir. Then, the article is built on three main pillars: The molecular mechanisms related to latency, the different strategies for targeting the reservoir to obtain a cure, and the current progress in immunotherapy to counteract said reservoirs.
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Affiliation(s)
- Mateo Chvatal-Medina
- Grupo Inmunovirología, Facultad de Medicina, Universidad de Antioquia, Medellín, Colombia
| | - Carolina Lopez-Guzman
- Grupo Inmunovirología, Facultad de Medicina, Universidad de Antioquia, Medellín, Colombia
| | - Francisco J Diaz
- Grupo Inmunovirología, Facultad de Medicina, Universidad de Antioquia, Medellín, Colombia
| | - Salomon Gallego
- Grupo de Investigaciones Biomédicas Uniremington, Programa de Medicina, Facultad de Ciencias de la Salud, Corporación Universitaria Remington, Medellín, Colombia
| | - Maria T Rugeles
- Grupo Inmunovirología, Facultad de Medicina, Universidad de Antioquia, Medellín, Colombia
| | - Natalia A Taborda
- Grupo Inmunovirología, Facultad de Medicina, Universidad de Antioquia, Medellín, Colombia.
- Grupo de Investigaciones Biomédicas Uniremington, Programa de Medicina, Facultad de Ciencias de la Salud, Corporación Universitaria Remington, Medellín, Colombia.
- Universidad Cooperativa de Colombia, Campus Medellin, Envigado, Colombia.
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5
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Qian G, Zhang Y, Liu Y, Li M, Xin B, Jiang W, Han W, Wang Y, Tang X, Li L, Zhu L, Sun T, Yan B, Zheng Y, Xu J, Ge B, Zhang Z, Yan D. Glutamylation of an HIV-1 protein inhibits the immune response by hijacking STING. Cell Rep 2023; 42:112442. [PMID: 37099423 DOI: 10.1016/j.celrep.2023.112442] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 03/04/2023] [Accepted: 04/12/2023] [Indexed: 04/27/2023] Open
Abstract
Cyclic GMP-AMP synthase (cGAS) recognizes Y-form cDNA of human immunodeficiency virus type 1 (HIV-1) and initiates antiviral immune response through cGAS-stimulator of interferon genes (STING)-TBK1-IRF3-type I interferon (IFN-I) signalingcascade. Here, we report that the HIV-1 p6 protein suppresses HIV-1-stimulated expression of IFN-I and promotes immune evasion. Mechanistically, the glutamylated p6 at residue Glu6 inhibits the interaction between STING and tripartite motif protein 32 (TRIM32) or autocrine motility factor receptor (AMFR). This subsequently suppresses the K27- and K63-linked polyubiquitination of STING at K337, therefore inhibiting STING activation, whereas mutation of the Glu6 residue partially reverses the inhibitory effect. However, CoCl2, an agonist of cytosolic carboxypeptidases (CCPs), counteracts the glutamylation of p6 at the Glu6 residue and inhibits HIV-1 immune evasion. These findings reveal a mechanism through which an HIV-1 protein mediates immune evasion and provides a therapeutic drug candidate to treat HIV-1 infection.
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Affiliation(s)
- Gui Qian
- Department of Immunology, School of Basic Medical Sciences, Shanghai Institute of Infectious Disease and Biosecurity & Shanghai Public Health Clinical Center, Fudan University, Shanghai 200032, China
| | - Yihua Zhang
- Department of Immunology, School of Basic Medical Sciences, Shanghai Institute of Infectious Disease and Biosecurity & Shanghai Public Health Clinical Center, Fudan University, Shanghai 200032, China
| | - Yinan Liu
- Department of Immunology, School of Basic Medical Sciences, Shanghai Institute of Infectious Disease and Biosecurity & Shanghai Public Health Clinical Center, Fudan University, Shanghai 200032, China
| | - Manman Li
- Department of Immunology, School of Basic Medical Sciences, Shanghai Institute of Infectious Disease and Biosecurity & Shanghai Public Health Clinical Center, Fudan University, Shanghai 200032, China
| | - Bowen Xin
- Department of Immunology, School of Basic Medical Sciences, Shanghai Institute of Infectious Disease and Biosecurity & Shanghai Public Health Clinical Center, Fudan University, Shanghai 200032, China
| | - Wenyi Jiang
- Department of Immunology, School of Basic Medical Sciences, Shanghai Institute of Infectious Disease and Biosecurity & Shanghai Public Health Clinical Center, Fudan University, Shanghai 200032, China
| | - Wendong Han
- Biosafety Level 3 Laboratory, Fudan University, Shanghai 200032, China
| | - Yu Wang
- National Engineering Research Centre of Immunological Products, Department of Microbiology and Biochemical Pharmacy, College of Pharmacy, Army Medical University, Chongqing 400038, China
| | - Xian Tang
- Institute for Hepatology, National Clinical Research Center for Infectious Disease, Shenzhen Third People's Hospital, School of Medicine, Southern University of Science and Technology, Shenzhen, Guangdong Province 518112, China
| | - Liuyan Li
- Department of Immunology, School of Basic Medical Sciences, Shanghai Institute of Infectious Disease and Biosecurity & Shanghai Public Health Clinical Center, Fudan University, Shanghai 200032, China
| | - Lingyan Zhu
- Department of Immunology, School of Basic Medical Sciences, Shanghai Institute of Infectious Disease and Biosecurity & Shanghai Public Health Clinical Center, Fudan University, Shanghai 200032, China
| | - Tao Sun
- Department of Immunology, School of Basic Medical Sciences, Shanghai Institute of Infectious Disease and Biosecurity & Shanghai Public Health Clinical Center, Fudan University, Shanghai 200032, China
| | - Bo Yan
- Department of Immunology, School of Basic Medical Sciences, Shanghai Institute of Infectious Disease and Biosecurity & Shanghai Public Health Clinical Center, Fudan University, Shanghai 200032, China
| | - Yongtang Zheng
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences, KIZ-CUHK Joint Laboratory of Bioresources and Molecular Research in Common Diseases, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650223, China
| | - Jianqing Xu
- Shanghai Key Laboratory of Organ Transplantation, Zhongshan Hospital & Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, China
| | - Baoxue Ge
- Shanghai TB Key Laboratory, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai 200433, China
| | - Zheng Zhang
- Institute for Hepatology, National Clinical Research Center for Infectious Disease, Shenzhen Third People's Hospital, School of Medicine, Southern University of Science and Technology, Shenzhen, Guangdong Province 518112, China
| | - Dapeng Yan
- Department of Immunology, School of Basic Medical Sciences, Shanghai Institute of Infectious Disease and Biosecurity & Shanghai Public Health Clinical Center, Fudan University, Shanghai 200032, China.
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6
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Sleman S, Najmuldeen H, Hao H, Jalal P, Saeed N, Othman D, Qian Z. Human cytomegalovirus UL24 and UL43 products participate in SAMHD1 subcellular localization. Virusdisease 2022; 33:383-396. [PMID: 36447815 PMCID: PMC9701276 DOI: 10.1007/s13337-022-00799-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Accepted: 10/09/2022] [Indexed: 11/13/2022] Open
Abstract
This report has analyzed the potential role of Human Cytomegalovirus (HCMV) UL24 and UL43 products in modulating the subcellular location of a host restriction factor, SAMHD1, in cells of human fibroblast origin. Recent studies have reported that the regulation of SAMHD1 is mediated by the HCMV UL97 product inside the nucleus, and by the CDK pathway when it is located in the cytoplasm of the infected cells but the viral gene products that may involve in cytosolic relocalization remain unknown yet. In the present report, we demonstrate that the HCMV UL24 product interacts with the SAMHD1 protein during infection based on mass spectrometry (MS) data and immunoprecipitation assay. The expression or depletion of the viral UL24 gene product did not affect the subcellular localization of SAMHD1 but when it coexpressed with the viral UL43 gene product, another member of the HCMV US22 family, induced the SAMHD1 cytosolic relocalization. Interestingly, the double deletion of viral UL24 and UL43 gene products impaired the cytosolic translocation and the SAMHD1 was accumulated in the nucleus of the infected cells, especially at the late stage post-infection. Our results provide evidence that the viral UL24 and UL43 gene products play a role in the SAMHD1 subcellular localization during HCMV infection. Supplementary Information The online version contains supplementary material available at 10.1007/s13337-022-00799-3.
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Affiliation(s)
- Sirwan Sleman
- College of Vet Medicine, University of Sulaimani, Sulaymaniyah, Iraq
- Unit of Herpesvirus and Molecular Virology, Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai, China
| | - Hastyar Najmuldeen
- Medical Laboratory Analysis, College of Health Science, Cihan University of Sulaimani, Sulaymaniyah, Iraq
| | - Hongyun Hao
- Unit of Herpesvirus and Molecular Virology, Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai, China
| | - Paywast Jalal
- Biology Department, College of Sciences, University of Sulaimani, Sulaymaniyah, Iraq
| | - Nahla Saeed
- College of Vet Medicine, University of Sulaimani, Sulaymaniyah, Iraq
| | - Dyary Othman
- College of Vet Medicine, University of Sulaimani, Sulaymaniyah, Iraq
| | - Zhikang Qian
- Unit of Herpesvirus and Molecular Virology, Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai, China
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7
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Hsueh BY, Severin GB, Elg CA, Waldron EJ, Kant A, Wessel AJ, Dover JA, Rhoades CR, Ridenhour BJ, Parent KN, Neiditch MB, Ravi J, Top EM, Waters CM. Phage defence by deaminase-mediated depletion of deoxynucleotides in bacteria. Nat Microbiol 2022; 7:1210-1220. [PMID: 35817890 PMCID: PMC9830645 DOI: 10.1038/s41564-022-01162-4] [Citation(s) in RCA: 40] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Accepted: 05/24/2022] [Indexed: 02/03/2023]
Abstract
Vibrio cholerae biotype El Tor is perpetuating the longest cholera pandemic in recorded history. The genomic islands VSP-1 and VSP-2 distinguish El Tor from previous pandemic V. cholerae strains. Using a co-occurrence analysis of VSP genes in >200,000 bacterial genomes we built gene networks to infer biological functions encoded in these islands. This revealed that dncV, a component of the cyclic-oligonucleotide-based anti-phage signalling system (CBASS) anti-phage defence system, co-occurs with an uncharacterized gene vc0175 that we rename avcD for anti-viral cytodine deaminase. We show that AvcD is a deoxycytidylate deaminase and that its activity is post-translationally inhibited by a non-coding RNA named AvcI. AvcID and bacterial homologues protect bacterial populations against phage invasion by depleting free deoxycytidine nucleotides during infection, thereby decreasing phage replication. Homologues of avcD exist in all three domains of life, and bacterial AvcID defends against phage infection by combining traits of two eukaryotic innate viral immunity proteins, APOBEC and SAMHD1.
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Affiliation(s)
- Brian Y Hsueh
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, USA
| | - Geoffrey B Severin
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, USA
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI, USA
| | - Clinton A Elg
- Department of Biological Sciences, Institute for Interdisciplinary Data Sciences, Bioinformatics and Computational Biology Program, University of Idaho, Moscow, ID, USA
| | - Evan J Waldron
- Department of Microbiology, Biochemistry, and Molecular Genetics, New Jersey Medical School, Rutgers University, Newark, NJ, USA
- Department of Pathology and Cell Biology, Columbia University, New York, NY, USA
| | - Abhiruchi Kant
- Department of Microbiology, Biochemistry, and Molecular Genetics, New Jersey Medical School, Rutgers University, Newark, NJ, USA
| | - Alex J Wessel
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, USA
| | - John A Dover
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, USA
| | - Christopher R Rhoades
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, USA
| | - Benjamin J Ridenhour
- Department of Mathematics and Statistical Sciences, University of Idaho, Moscow, ID, USA
| | - Kristin N Parent
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, USA
| | - Matthew B Neiditch
- Department of Microbiology, Biochemistry, and Molecular Genetics, New Jersey Medical School, Rutgers University, Newark, NJ, USA
| | - Janani Ravi
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, USA
- Department of Pathobiology and Diagnostic Investigation, Michigan State University, East Lansing, MI, USA
| | - Eva M Top
- Department of Biological Sciences, Institute for Interdisciplinary Data Sciences, Bioinformatics and Computational Biology Program, University of Idaho, Moscow, ID, USA
| | - Christopher M Waters
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, USA.
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8
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Bacteria deplete deoxynucleotides to defend against bacteriophage infection. Nat Microbiol 2022; 7:1200-1209. [PMID: 35817891 DOI: 10.1038/s41564-022-01158-0] [Citation(s) in RCA: 49] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Accepted: 05/23/2022] [Indexed: 11/09/2022]
Abstract
DNA viruses and retroviruses consume large quantities of deoxynucleotides (dNTPs) when replicating. The human antiviral factor SAMHD1 takes advantage of this vulnerability in the viral lifecycle, and inhibits viral replication by degrading dNTPs into their constituent deoxynucleosides and inorganic phosphate. Here, we report that bacteria use a similar strategy to defend against bacteriophage infection. We identify a family of defensive bacterial deoxycytidine triphosphate (dCTP) deaminase proteins that convert dCTP into deoxyuracil nucleotides in response to phage infection. We also identify a family of phage resistance genes that encode deoxyguanosine triphosphatase (dGTPase) enzymes, which degrade dGTP into phosphate-free deoxyguanosine and are distant homologues of human SAMHD1. Our results suggest that bacterial defensive proteins deplete specific deoxynucleotides (either dCTP or dGTP) from the nucleotide pool during phage infection, thus starving the phage of an essential DNA building block and halting its replication. Our study shows that manipulation of the dNTP pool is a potent antiviral strategy shared by both prokaryotes and eukaryotes.
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9
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Bacterial origins of human cell-autonomous innate immune mechanisms. Nat Rev Immunol 2022; 22:629-638. [PMID: 35396464 DOI: 10.1038/s41577-022-00705-4] [Citation(s) in RCA: 96] [Impact Index Per Article: 48.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/03/2022] [Indexed: 12/11/2022]
Abstract
The cell-autonomous innate immune system enables animal cells to resist viral infection. This system comprises an array of sensors that, after detecting viral molecules, activate the expression of antiviral proteins and the interferon response. The repertoire of immune sensors and antiviral proteins has long been considered to be derived from extensive evolutionary innovation in vertebrates, but new data challenge this dogma. Recent studies show that central components of the cell-autonomous innate immune system have ancient evolutionary roots in prokaryotic genes that protect bacteria from phages. These include the cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) pathway, Toll/IL-1 receptor (TIR) domain-containing pathogen receptors, the viperin family of antiviral proteins, SAMHD1-like nucleotide-depletion enzymes, gasdermin proteins and key components of the RNA interference pathway. This Perspective details current knowledge of the elements of antiviral immunity that are conserved from bacteria to humans, and presents possible evolutionary scenarios to explain the observed conservation.
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10
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Wang Y, Qian G, Zhu L, Zhao Z, Liu Y, Han W, Zhang X, Zhang Y, Xiong T, Zeng H, Yu X, Yu X, Zhang X, Xu J, Zou Q, Yan D. HIV-1 Vif suppresses antiviral immunity by targeting STING. Cell Mol Immunol 2022; 19:108-121. [PMID: 34811497 PMCID: PMC8752805 DOI: 10.1038/s41423-021-00802-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Accepted: 10/25/2021] [Indexed: 01/03/2023] Open
Abstract
HIV-1 infection-induced cGAS-STING-TBK1-IRF3 signaling activates innate immunity to produce type I interferon (IFN). The HIV-1 nonstructural protein viral infectivity factor (Vif) is essential in HIV-1 replication, as it degrades the host restriction factor APOBEC3G. However, whether and how it regulates the host immune response remains to be determined. In this study, we found that Vif inhibited the production of type I IFN to promote immune evasion. HIV-1 infection induced the activation of the host tyrosine kinase FRK, which subsequently phosphorylated the immunoreceptor tyrosine-based inhibitory motif (ITIM) of Vif and enhanced the interaction between Vif and the cellular tyrosine phosphatase SHP-1 to inhibit type I IFN. Mechanistically, the association of Vif with SHP-1 facilitated SHP-1 recruitment to STING and inhibited the K63-linked ubiquitination of STING at Lys337 by dephosphorylating STING at Tyr162. However, the FRK inhibitor D-65495 counteracted the phosphorylation of Vif to block the immune evasion of HIV-1 and antagonize infection. These findings reveal a previously unknown mechanism through which HIV-1 evades antiviral immunity via the ITIM-containing protein to inhibit the posttranslational modification of STING. These results provide a molecular basis for the development of new therapeutic strategies to treat HIV-1 infection.
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Affiliation(s)
- Yu Wang
- grid.8547.e0000 0001 0125 2443Department of Immunology, School of Basic Medical Sciences, Shanghai Institute of Infectious Disease and Biosecurity & Shanghai Public Health Clinical Center, Fudan University, Shanghai, 200032 China ,grid.410570.70000 0004 1760 6682National Engineering Research Centre of Immunological Products, Department of Microbiology and Biochemical Pharmacy, College of Pharmacy, Army Medical University, Chongqing, 400038 China ,grid.410570.70000 0004 1760 6682Department of Basic Courses, NCO School, Army Medical University, Shijiazhuang, 050081 China
| | - Gui Qian
- grid.8547.e0000 0001 0125 2443Department of Immunology, School of Basic Medical Sciences, Shanghai Institute of Infectious Disease and Biosecurity & Shanghai Public Health Clinical Center, Fudan University, Shanghai, 200032 China
| | - Lingyan Zhu
- grid.8547.e0000 0001 0125 2443Department of Immunology, School of Basic Medical Sciences, Shanghai Institute of Infectious Disease and Biosecurity & Shanghai Public Health Clinical Center, Fudan University, Shanghai, 200032 China
| | - Zhuo Zhao
- grid.410570.70000 0004 1760 6682National Engineering Research Centre of Immunological Products, Department of Microbiology and Biochemical Pharmacy, College of Pharmacy, Army Medical University, Chongqing, 400038 China
| | - Yinan Liu
- grid.8547.e0000 0001 0125 2443Department of Immunology, School of Basic Medical Sciences, Shanghai Institute of Infectious Disease and Biosecurity & Shanghai Public Health Clinical Center, Fudan University, Shanghai, 200032 China
| | - Wendong Han
- grid.8547.e0000 0001 0125 2443Biosafety Level 3 Laboratory, Fudan University, Shanghai, 200032 China
| | - Xiaokai Zhang
- grid.410570.70000 0004 1760 6682National Engineering Research Centre of Immunological Products, Department of Microbiology and Biochemical Pharmacy, College of Pharmacy, Army Medical University, Chongqing, 400038 China
| | - Yihua Zhang
- grid.8547.e0000 0001 0125 2443Department of Immunology, School of Basic Medical Sciences, Shanghai Institute of Infectious Disease and Biosecurity & Shanghai Public Health Clinical Center, Fudan University, Shanghai, 200032 China
| | - Tingrong Xiong
- grid.410570.70000 0004 1760 6682National Engineering Research Centre of Immunological Products, Department of Microbiology and Biochemical Pharmacy, College of Pharmacy, Army Medical University, Chongqing, 400038 China
| | - Hao Zeng
- grid.410570.70000 0004 1760 6682National Engineering Research Centre of Immunological Products, Department of Microbiology and Biochemical Pharmacy, College of Pharmacy, Army Medical University, Chongqing, 400038 China
| | - Xianghui Yu
- grid.64924.3d0000 0004 1760 5735National Engineering Laboratory for AIDS Vaccine, School of Life Sciences, Jilin University, Changchun, 130012 China
| | - Xiaofang Yu
- grid.430605.40000 0004 1758 4110Institute of Virology and AIDS Research, The First Hospital of Jilin University, Changchun, 130061 China
| | - Xiaoyan Zhang
- grid.8547.e0000 0001 0125 2443Department of Immunology, School of Basic Medical Sciences, Shanghai Institute of Infectious Disease and Biosecurity & Shanghai Public Health Clinical Center, Fudan University, Shanghai, 200032 China
| | - Jianqing Xu
- grid.8547.e0000 0001 0125 2443Shanghai Key Laboratory of Organ Transplantation, Zhongshan Hospital & Institutes of Biomedical Sciences, Fudan University, Shanghai, 200032 China
| | - Quanming Zou
- grid.410570.70000 0004 1760 6682National Engineering Research Centre of Immunological Products, Department of Microbiology and Biochemical Pharmacy, College of Pharmacy, Army Medical University, Chongqing, 400038 China
| | - Dapeng Yan
- grid.8547.e0000 0001 0125 2443Department of Immunology, School of Basic Medical Sciences, Shanghai Institute of Infectious Disease and Biosecurity & Shanghai Public Health Clinical Center, Fudan University, Shanghai, 200032 China
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11
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Ren H, Yin X, Su C, Guo M, Wang XF, Na L, Lin Y, Wang X. Equine lentivirus counteracts SAMHD1 restriction by Rev-mediated degradation of SAMHD1 via the BECN1-dependent lysosomal pathway. Autophagy 2021; 17:2800-2817. [PMID: 33172327 PMCID: PMC8525956 DOI: 10.1080/15548627.2020.1846301] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 10/16/2020] [Accepted: 10/30/2020] [Indexed: 02/09/2023] Open
Abstract
The innate immune restriction factor SAMHD1 can inhibit diverse viruses in myeloid cells. Mechanistically, SAMHD1 inhibits lentiviral replication including HIV-1 by depleting the nucleotide pool to interfere with their reverse transcription. Equine infectious anemia virus (EIAV) is an ancient lentivirus that preferentially attacks macrophages. However, the mechanism by which EIAV successfully establishes infection in macrophages with functional SAMHD1 remains unclear. Here, we demonstrate that while equine SAMDH1 can limit EIAV replication in equine macrophages at the reverse transcription stage, the antiviral effect is counteracted by the well-known transcriptional regulator Rev, which downregulates equine SAMHD1 through the lysosomal pathway. Remarkably, Rev hijacks BECN1 (beclin 1) and PIK3C3 to mediate SAMHD1 degradation in a canonical macroautophagy/autophagy-independent pathway. Our study illustrates that equine lentiviral Rev possesses important functions in evading cellular innate immunity in addition to its RNA regulatory function, and may provide new insights into the co-evolutionary arms race between SAMHD1 and lentiviruses.Abbreviations:3-MA: 3-methyladenine; AA: amino acid; ACTB: actin beta; AD: activation domain; ATG: autophagy related; Baf A1: bafilomycin A1; BD: binding domain; BECN1: beclin 1; BH3: BCL2-homology-3 domain; BiFC: bimolecular fluorescence complementation; CCD: coiled-coil domain; class III PtdIns3K: class III phosphatidylinositol 3-kinase; CQ: chloroquine; Co-IP: co-immunoprecipitation; dNTPase: dGTP-stimulated deoxynucleoside triphosphate triphosphohydrolase; ECD: evolutionarily conserved domain; EIAV: equine infectious anemia virus; eMDMs: equine monocyte-derived macrophages; GFP: green fluorescent protein; HD: histidine-aspartic; HIV-1: human immunodeficiency virus-1; hpi: hours post infection; hpt: hours post transfection; KO: knockout; LAMP2: lysosomal associated membrane protein 2; LMB: leptomycin B; PMA: phorbol 12-myristate 13-acetate; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; ND: unknown non-essential domain; NES: nuclear export signal; NLS: localization signal; NS: statistically non-significant; PIK3C3: phosphatidylinositol 3-kinase catalytic subunit type 3; RBD: RNA binding domain; RT: reverse transcriptase; siRNAs: small interfering RNAs; SAMHD1: SAM and HD domain containing deoxynucleoside triphosphate triphosphohydrolase 1; SIV: simian immunodeficiency virus; VN: C-terminal residues of Venus 174 to 238; VC: N-terminal residues 2 to 173 of Venus.
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Affiliation(s)
- Huiling Ren
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, the Chinese Academy of Agricultural Sciences, Harbin, China
| | - Xin Yin
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, the Chinese Academy of Agricultural Sciences, Harbin, China
| | - Chao Su
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, the Chinese Academy of Agricultural Sciences, Harbin, China
| | - Miaomiao Guo
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, the Chinese Academy of Agricultural Sciences, Harbin, China
| | - Xue-Feng Wang
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, the Chinese Academy of Agricultural Sciences, Harbin, China
| | - Lei Na
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, the Chinese Academy of Agricultural Sciences, Harbin, China
| | - Yuezhi Lin
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, the Chinese Academy of Agricultural Sciences, Harbin, China
| | - Xiaojun Wang
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, the Chinese Academy of Agricultural Sciences, Harbin, China
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12
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Pinzone MR, Bertuccio MP, VanBelzen DJ, Zurakowski R, O'Doherty U. Next-Generation Sequencing in a Direct Model of HIV Infection Reveals Important Parallels to and Differences from In Vivo Reservoir Dynamics. J Virol 2020; 94:e01900-19. [PMID: 32051279 PMCID: PMC7163122 DOI: 10.1128/jvi.01900-19] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Accepted: 02/04/2020] [Indexed: 02/06/2023] Open
Abstract
Next-generation sequencing (NGS) represents a powerful tool to unravel the genetic make-up of the HIV reservoir, but limited data exist on its use in vitro Moreover, most NGS studies do not separate integrated from unintegrated DNA, even though selection pressures on these two forms should be distinct. We reasoned we could use NGS to compare the infection of resting and activated CD4 T cells in vitro to address how the metabolic state affects reservoir formation and dynamics. To address these questions, we obtained HIV sequences 2, 4, and 8 days after NL4-3 infection of metabolically activated and quiescent CD4 T cells (cultured with 2 ng/ml interleukin-7). We compared the composition of integrated and total HIV DNA by isolating integrated HIV DNA using pulsed-field electrophoresis before performing sequencing. After a single-round infection, the majority of integrated HIV DNA was intact in both resting and activated T cells. The decay of integrated intact proviruses was rapid and similar in both quiescent and activated T cells. Defective forms accumulated relative to intact ones analogously to what is observed in vivo Massively deleted viral sequences formed more frequently in resting cells, likely due to lower deoxynucleoside triphosphate (dNTP) levels and the presence of multiple restriction factors. To our surprise, the majority of these deleted sequences did not integrate into the human genome. The use of NGS to study reservoir dynamics in vitro provides a model that recapitulates important aspects of reservoir dynamics. Moreover, separating integrated from unintegrated HIV DNA is important in some clinical settings to properly study selection pressures.IMPORTANCE The major implication of our work is that the decay of intact proviruses in vitro is extremely rapid, perhaps as a result of enhanced expression. Gaining a better understanding of why intact proviruses decay faster in vitro might help the field identify strategies to purge the reservoir in vivo When used wisely, in vitro models are a powerful tool to study the selective pressures shaping the viral landscape. Our finding that massively deleted sequences rarely succeed in integrating has several ramifications. It demonstrates that the total HIV DNA can differ substantially in character from the integrated HIV DNA under certain circumstances. The presence of unintegrated HIV DNA has the potential to obscure selection pressures and confound the interpretation of clinical studies, especially in the case of trials involving treatment interruptions.
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Affiliation(s)
- Marilia Rita Pinzone
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Maria Paola Bertuccio
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Department of Biomedical and Dental Sciences and Morphofunctional Imaging, University of Messina, Messina, Italy
| | - D Jake VanBelzen
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Department of Molecular Biosciences, Northwestern University, Evanston, Illinois, USA
| | - Ryan Zurakowski
- Delaware Biotechnology Institute, University of Delaware, Newark, Delaware, USA
| | - Una O'Doherty
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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13
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Metabolomic Analysis of Influenza A Virus A/WSN/1933 (H1N1) Infected A549 Cells during First Cycle of Viral Replication. Viruses 2019; 11:v11111007. [PMID: 31683654 PMCID: PMC6893833 DOI: 10.3390/v11111007] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Revised: 10/29/2019] [Accepted: 10/29/2019] [Indexed: 12/11/2022] Open
Abstract
Influenza A virus (IAV) has developed strategies to utilize host metabolites which, after identification and isolation, can be used to discover the value of immunometabolism. During this study, to mimic the metabolic processes of influenza virus infection in human cells, we infect A549 cells with H1N1 (WSN) influenza virus and explore the metabolites with altered levels during the first cycle of influenza virus infection using ultra-high-pressure liquid chromatography-quadrupole time-of-flight mass spectrometer (UHPLC-Q-TOF MS) technology. We annotate the metabolites using MetaboAnalyst and the Kyoto Encyclopedia of Genes and Genomes pathway analyses, which reveal that IAV regulates the abundance of the metabolic products of host cells during early infection to provide the energy and metabolites required to efficiently complete its own life cycle. These metabolites are correlated with the tricarboxylic acid (TCA) cycle and mainly are involved in purine, lipid, and glutathione metabolisms. Concurrently, the metabolites interact with signal receptors in A549 cells to participate in cellular energy metabolism signaling pathways. Metabonomic analyses have revealed that, in the first cycle, the virus not only hijacks cell metabolism for its own replication, but also affects innate immunity, indicating a need for further study of the complex relationship between IAV and host cells.
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14
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Choi J, Hwang SY, Ahn K. Interplay between RNASEH2 and MOV10 controls LINE-1 retrotransposition. Nucleic Acids Res 2019; 46:1912-1926. [PMID: 29315404 PMCID: PMC5829647 DOI: 10.1093/nar/gkx1312] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Accepted: 12/23/2017] [Indexed: 01/22/2023] Open
Abstract
Long interspersed nuclear element 1 is an autonomous non-long terminal repeat retrotransposon that comprises ∼17% of the human genome. Its spontaneous retrotransposition and the accumulation of heritable L1 insertions can potentially result in genome instability and sporadic disorders. Moloney leukemia virus 10 homolog (MOV10), a putative RNA helicase, has been implicated in inhibiting L1 replication, although its underlying mechanism of action remains obscure. Moreover, the physiological relevance of MOV10-mediated L1 regulation in human disease has not yet been examined. Using a proteomic approach, we identified RNASEH2 as a binding partner of MOV10. We show that MOV10 interacts with RNASEH2, and their interplay is crucial for restricting L1 retrotransposition. RNASEH2 and MOV10 co-localize in the nucleus, and RNASEH2 binds to L1 RNAs in a MOV10-dependent manner. Small hairpin RNA-mediated depletion of either RNASEH2A or MOV10 results in an accumulation of L1-specific RNA-DNA hybrids, suggesting they contribute to prevent formation of vital L1 heteroduplexes during retrotransposition. Furthermore, we show that RNASEH2-MOV10-mediated L1 restriction downregulates expression of the rheumatoid arthritis-associated inflammatory cytokines and matrix-degrading proteinases in synovial cells, implicating a potential causal relationship between them and disease development in terms of disease predisposition.
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Affiliation(s)
- Jongsu Choi
- Center for RNA Research, Institute for Basic Science, Seoul 08826, Republic of Korea.,School of Biological Sciences, Seoul National University, Seoul 08826, Republic of Korea
| | - Sung-Yeon Hwang
- Center for RNA Research, Institute for Basic Science, Seoul 08826, Republic of Korea.,School of Biological Sciences, Seoul National University, Seoul 08826, Republic of Korea
| | - Kwangseog Ahn
- Center for RNA Research, Institute for Basic Science, Seoul 08826, Republic of Korea.,School of Biological Sciences, Seoul National University, Seoul 08826, Republic of Korea
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15
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Xu X, Li M, Li D, Jiang Z, Liu C, Shi X, Wu C, Chen X, Lin G, Hu C. Identification of the SAMHD1 gene in grass carp and its roles in inducing apoptosis and inhibiting GCRV proliferation. FISH & SHELLFISH IMMUNOLOGY 2019; 88:606-618. [PMID: 30885743 DOI: 10.1016/j.fsi.2019.03.028] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2018] [Revised: 03/10/2019] [Accepted: 03/12/2019] [Indexed: 06/09/2023]
Abstract
SAMHD1 is an innate immunity restriction factor that inhibits virus infection through IRF3-mediated antiviral and apoptotic responses. Fish SAMHD1 shares some similar properties with those in mammals. In this study, a SAMHD1 orthologue from grass carp (Ctenopharyngodon idellus) was cloned and characterized. The full-length cDNA of CiSAMHD1 is 2792 bp with an ORF of 1884 bp encoding a polypeptide of 627 amino acids. Multiple alignments showed that SAMHD1 is highly conserved among different species. Phylogenetic tree analysis revealed that CiSAMHD1 shared a high degree of homology with Sinocyclocheilus rhinocerous SAMHD1. Expression analysis indicated that CiSAMHD1 was widely expressed in all tissues tested including the brain, eyes, spleen, gill, intestine, liver, heart and kidney. It was significantly up-regulated in spleen, liver and intestines after treatment with poly I:C. Also, CiSAMHD1 can be induced following stimulation with recombinant IFN in CIK cells. The promoter sequence of CiSAMHD1 was identified to explore the mechanism underlying the transcriptional regulation of CiSAMHD1. The promoter sequence of CiSAMHD1 (1370 bp) consists of IRF1, IRF3, IRF9 and p65 binding elements. Gel mobility shift assay also showed that IRF1, IRF3, IRF9 and p65 prokaryotic proteins can separately interact with CiSAMHD1 promoter. Dual luciferase assay and q-PCR suggested that the promoter of CiSAMHD1 can be activated by the overexpression of CiIRF3 and CiIRF9, but cannot be triggered by CiIRF1 and Cip65. In contrast, knockdown of CiIRF3 or CiIRF9 inhibits the transcription of CiSAMHD1. Intriguingly, CCK assay suggested that CiSAMHD1 decreased cell viability. TUNEL apoptosis assay and Hoechst 33258 staining assay indicated that apoptosis is induced by the overexpression of CiSAMHD1. Crystal violet staining, detection of two GCRV genes (vp3 and vp5) and viral titration showed that CiSAMHD1 can suppress the proliferation of grass carp reovirus (GCRV) in CIK cells.
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Affiliation(s)
- Xiaowen Xu
- College of Life Science, Nanchang University, Nanchang, 330031, China
| | - Meifeng Li
- College of Life Science, Nanchang University, Nanchang, 330031, China
| | - Dongming Li
- Fuzhou Medical College, Nanchang University, Fuzhou 344000, China
| | - Zeyin Jiang
- College of Life Science, Nanchang University, Nanchang, 330031, China
| | - Changxin Liu
- College of Life Science, Nanchang University, Nanchang, 330031, China
| | - Xiao Shi
- College of Life Science, Nanchang University, Nanchang, 330031, China
| | - Chuxin Wu
- Yuzhang Normal University, Nanchang 330031, China
| | - Xingxing Chen
- College of Life Science, Nanchang University, Nanchang, 330031, China
| | - Gang Lin
- College of Life Science, Nanchang University, Nanchang, 330031, China.
| | - Chengyu Hu
- College of Life Science, Nanchang University, Nanchang, 330031, China.
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16
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Nucleocytoplasmic shuttling of SAMHD1 is important for LINE-1 suppression. Biochem Biophys Res Commun 2019; 510:551-557. [DOI: 10.1016/j.bbrc.2019.02.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Accepted: 02/02/2019] [Indexed: 11/21/2022]
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17
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Li M, Xu X, Jiang Z, Liu C, Shi X, Qi G, Li Y, Chen X, Huang Q, Mao H, Hu C. Fish SAMHD1 performs as an activator for IFN expression. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2018; 86:138-146. [PMID: 29753769 DOI: 10.1016/j.dci.2018.05.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Revised: 04/11/2018] [Accepted: 05/07/2018] [Indexed: 06/08/2023]
Abstract
As a host limiting factor, Sterile Alpha Motif and Histidine-Aspartate Domain 1 protein (SAMHD1) is associated with IRF3-mediated antiviral and apoptotic responses in mammals. However, the antiviral mechanism of SAMHD1 remains indistinct in fish. In this study, we found the expression of Ctenopharyngodon idella SAMHD1 (MF326081) was up-regulated after transfection with poly I:C (dsRNA analog), B-DNA or Z-DNA into C. idella kidney cells (CIKs), but these expression profiles had no obvious change when the cells were incubated with these nucleic acids. These data may indicate that CiSAMHD1 participates in the intracellular PRR-mediated signaling pathway rather than extracellular PRR-mediated signaling pathway. Subcellular localization assay suggested that a part of over-expressed CiSAMHD1 were translocated from nuclear to cytoplasm when C. idella ovary cells (COs) were transfected with poly I:C, B-DNA or Z-DNA. Nucleic acid pulldown assays were performed to investigate the reason for nuclear-cytoplasm translocation of CiSAMHD1. The results showed that CiSAMHD1 had a high affinity with B-DNA, Z-DNA and ISD-PS (dsRNA analog). In addition, co-IP assays revealed the interaction of CiSAMHD1 with CiSTING (KF494194). Taken together, all these results suggest that grass carp SAMHD1 performs as an activator for innate immune response through STING-mediated signaling pathway.
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Affiliation(s)
- Meifeng Li
- College of Life Science, Key Lab of Aquatic Resources and Utilization of Jiangxi Province, Nanchang University, Nanchang, 330031, China
| | - Xiaowen Xu
- College of Life Science, Key Lab of Aquatic Resources and Utilization of Jiangxi Province, Nanchang University, Nanchang, 330031, China
| | - Zeyin Jiang
- College of Life Science, Key Lab of Aquatic Resources and Utilization of Jiangxi Province, Nanchang University, Nanchang, 330031, China
| | - Changxin Liu
- College of Life Science, Key Lab of Aquatic Resources and Utilization of Jiangxi Province, Nanchang University, Nanchang, 330031, China
| | - Xiao Shi
- College of Life Science, Key Lab of Aquatic Resources and Utilization of Jiangxi Province, Nanchang University, Nanchang, 330031, China
| | - Guoqin Qi
- College of Life Science, Key Lab of Aquatic Resources and Utilization of Jiangxi Province, Nanchang University, Nanchang, 330031, China
| | - Yinping Li
- College of Life Science, Key Lab of Aquatic Resources and Utilization of Jiangxi Province, Nanchang University, Nanchang, 330031, China
| | - Xin Chen
- College of Life Science, Key Lab of Aquatic Resources and Utilization of Jiangxi Province, Nanchang University, Nanchang, 330031, China
| | - Qingli Huang
- College of Life Science, Key Lab of Aquatic Resources and Utilization of Jiangxi Province, Nanchang University, Nanchang, 330031, China
| | - Huiling Mao
- College of Life Science, Key Lab of Aquatic Resources and Utilization of Jiangxi Province, Nanchang University, Nanchang, 330031, China
| | - Chengyu Hu
- College of Life Science, Key Lab of Aquatic Resources and Utilization of Jiangxi Province, Nanchang University, Nanchang, 330031, China.
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18
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SAMHD1 enhances immunoglobulin hypermutation by promoting transversion mutation. Proc Natl Acad Sci U S A 2018; 115:4921-4926. [PMID: 29669924 DOI: 10.1073/pnas.1719771115] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Activation-induced deaminase (AID) initiates hypermutation of Ig genes in activated B cells by converting C:G into U:G base pairs. G1-phase variants of uracil base excision repair (BER) and mismatch repair (MMR) then deploy translesion polymerases including REV1 and Pol η, which exacerbates mutation. dNTP paucity may contribute to hypermutation, because dNTP levels are reduced in G1 phase to inhibit viral replication. To derestrict G1-phase dNTP supply, we CRISPR-inactivated SAMHD1 (which degrades dNTPs) in germinal center B cells. Samhd1 inactivation increased B cell virus susceptibility, increased transition mutations at C:G base pairs, and substantially decreased transversion mutations at A:T and C:G base pairs in both strands. We conclude that SAMHD1's restriction of dNTP supply enhances AID's mutagenicity and that the evolution of Ig hypermutation included the repurposing of antiviral mechanisms based on dNTP starvation.
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19
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Halder UC. Bone marrow stem cells to destroy circulating HIV: a hypothetical therapeutic strategy. ACTA ACUST UNITED AC 2018; 25:3. [PMID: 29445623 PMCID: PMC5800069 DOI: 10.1186/s40709-018-0075-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2017] [Accepted: 01/27/2018] [Indexed: 12/19/2022]
Abstract
Human immunodeficiency virus (HIV) still poses enigmatic threats to human life. This virus has mastered in bypassing anti retroviral therapy leading to patients’ death. Circulating viruses are phenomenal for the disease outcome. This hypothesis proposes a therapeutic strategy utilizing receptor-integrated hematopoietic, erythroid and red blood cells. Here, HIV specific receptors trap circulating viruses that enter erythrocyte cytoplasm and form inactive integration complex. This model depicts easy, effective removal of circulating HIV without any adverse effect.
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Affiliation(s)
- Umesh Chandra Halder
- Department of Zoology, Raniganj Girls' College, Searsole, Rajbari, Raniganj, Paschim Barddhaman, West Bengal 713358 India
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20
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Iqbal K, Imran M, Ullah S, Jamal M, Waheed Y, Ali Q. Correlation of Apolipoprotein B mRNA-editing Enzyme, Catalytic Polypeptide- like 3G Genetic Variant rs8177832 with HIV-1 Predisposition in Pakistani Population. Curr HIV Res 2018; 16:297-301. [PMID: 30338740 PMCID: PMC6416456 DOI: 10.2174/1570162x16666181018155827] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Revised: 10/08/2018] [Accepted: 10/12/2018] [Indexed: 02/07/2023]
Abstract
BACKGROUND Human immunodeficiency virus (HIV) infection is a global health burden which ultimately results in acquired immune deficiency syndrome (AIDS). There are multiple host factors which are capable of limiting HIV-1 replication. One of the most important host factors which inhibit HIV-1 DNA synthesis is the apolipoprotein B mRNA-editing enzyme, catalytic polypeptide- like 3G (APOBEC3G). Any genetic variation of this important host factor may influence the host susceptibility to viral infection. OBJECTIVE The aim of the current study was to evaluate any correlation of APOBEC3G genetic variation rs8177832 with HIV-1 infection. METHODS The study involved 142 healthy control and 100 HIV-1 infected subjects. The genetic variation rs8177832 of all studied subjects was determined by allele-specific polymerase chain reaction (AS-PCR). RESULTS The results showed that the distribution of rs8177832 genotypes AA, AG and GG in healthy subjects and HIV-1 subjects was; 42.253%, 42.957%, 14.788% and 66%, 27%, 7% respectively. Statistical analyses of data showed that there was a significant variation in rs8177832 genotype AA in healthy control and HIV-1 infected subjects (42.257% vs 66%; p-value<0.001). CONCLUSION Thus it was concluded that APOBEC3G rs8177832 AA genotype contributes in genetic predisposition to HIV-1 infection in Pakistani population.
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Affiliation(s)
- Khurshid Iqbal
- Address correspondence to this author at the Department of Medical Laboratory Sciences, Imperial College of Business Studies, Lahore, Pakistan; Tel: 00923028051657; E-mail:
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21
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Patra KK, Bhattacharya A, Bhattacharya S. Allosteric Signal Transduction in HIV-1 Restriction Factor SAMHD1 Proceeds via Reciprocal Handshake across Monomers. J Chem Inf Model 2017; 57:2523-2538. [PMID: 28956603 DOI: 10.1021/acs.jcim.7b00279] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The sterile alpha motif and histidine-aspartate domain-containing protein 1 (or SAMHD1), a human dNTP-triphosphohydrolase, contributes to HIV-1 restriction in select terminally differentiated cells of the immune system. The catalytically active form of the protein is an allosterically triggered tetramer, whose HIV-1 restriction properties are attributed to its dNTP-triphosphohydrolase activity. The tetramer itself is assembled by a GTP/dNTP combination. This enzyme uses the strategy of deoxynucleotide starvation, which is thought to prevent effective reverse transcription of the retroviral genome-hence, restricting HIV-1 propagation. HIV-2 and SIV have evolved defenses against SAMHD1, underscoring its role in restriction. Previous studies have provided high-resolution structures of GTP/dNTP-bound enzyme complexes but have not been able to provide information on dynamics. In this study, we have used correlation network analysis along with MD techniques to study the flow of allosteric information across the active complex. We have found evidence of a reciprocal allosteric "handshake" occurring across monomeric units. We have also uncovered a short linker region as the nexus for funnelling the regulatory signal from phosphorylation at T592 from the surface to the interior core of the protein.
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Affiliation(s)
- Kajwal Kumar Patra
- Department of Physics, Indian Institute of Technology Guwahati , Guwahati, Assam, India 781039
| | - Akash Bhattacharya
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center at San Antonio , San Antonio, Texas 78229-3900, United States
| | - Swati Bhattacharya
- Department of Physics, Indian Institute of Technology Guwahati , Guwahati, Assam, India 781039.,Department of Chemical Engineering, Indian Institute of Technology Bombay , Mumbai, India 400076
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22
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Vpx overcomes a SAMHD1-independent block to HIV reverse transcription that is specific to resting CD4 T cells. Proc Natl Acad Sci U S A 2017; 114:2729-2734. [PMID: 28228523 DOI: 10.1073/pnas.1613635114] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Early after entry into monocytes, macrophages, dendritic cells, and resting CD4 T cells, HIV encounters a block, limiting reverse transcription (RT) of the incoming viral RNA genome. In this context, dNTP triphosphohydrolase SAM domain and HD domain-containing protein 1 (SAMHD1) has been identified as a restriction factor, lowering the concentration of dNTP substrates to limit RT. The accessory lentiviral protein X (Vpx) proteins from the major simian immunodeficiency virus of rhesus macaque, sooty mangabey, and HIV-2 (SIVsmm/SIVmac/HIV-2) lineage packaged into virions target SAMHD1 for proteasomal degradation, increase intracellular dNTP pools, and facilitate HIV cDNA synthesis. We find that virion-packaged Vpx proteins from a second SIV lineage, SIV of red-capped mangabeys or mandrills (SIVrcm/mnd-2), increased HIV infection in resting CD4 T cells, but not in macrophages, and, unexpectedly, acted in the absence of SAMHD1 degradation, dNTP pool elevation, or changes in SAMHD1 phosphorylation. Vpx rcm/mnd-2 virion incorporation resulted in a dramatic increase of HIV-1 RT intermediates and viral cDNA in infected resting CD4 T cells. These analyses also revealed a barrier limiting HIV-1 infection of resting CD4 T cells at the level of nuclear import. Single amino acid changes in the SAMHD1-degrading Vpx mac239 allowed it to enhance early postentry steps in a Vpx rcm/mnd-2-like fashion. Moreover, Vpx enhanced HIV-1 infection of SAMHD1-deficient resting CD4 T cells of a patient with Aicardi-Goutières syndrome. These results indicate that Vpx, in addition to SAMHD1, overcomes a previously unappreciated restriction for lentiviruses at the level of RT that acts independently of dNTP concentrations and is specific to resting CD4 T cells.
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Greenwood EJD, Matheson NJ, Wals K, van den Boomen DJH, Antrobus R, Williamson JC, Lehner PJ. Temporal proteomic analysis of HIV infection reveals remodelling of the host phosphoproteome by lentiviral Vif variants. eLife 2016; 5:e18296. [PMID: 27690223 PMCID: PMC5085607 DOI: 10.7554/elife.18296] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2016] [Accepted: 09/28/2016] [Indexed: 12/20/2022] Open
Abstract
Viruses manipulate host factors to enhance their replication and evade cellular restriction. We used multiplex tandem mass tag (TMT)-based whole cell proteomics to perform a comprehensive time course analysis of >6500 viral and cellular proteins during HIV infection. To enable specific functional predictions, we categorized cellular proteins regulated by HIV according to their patterns of temporal expression. We focussed on proteins depleted with similar kinetics to APOBEC3C, and found the viral accessory protein Vif to be necessary and sufficient for CUL5-dependent proteasomal degradation of all members of the B56 family of regulatory subunits of the key cellular phosphatase PP2A (PPP2R5A-E). Quantitative phosphoproteomic analysis of HIV-infected cells confirmed Vif-dependent hyperphosphorylation of >200 cellular proteins, particularly substrates of the aurora kinases. The ability of Vif to target PPP2R5 subunits is found in primate and non-primate lentiviral lineages, and remodeling of the cellular phosphoproteome is therefore a second ancient and conserved Vif function.
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Affiliation(s)
- Edward JD Greenwood
- Cambridge Institute for Medical Research, Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Nicholas J Matheson
- Cambridge Institute for Medical Research, Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Kim Wals
- Cambridge Institute for Medical Research, Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Dick JH van den Boomen
- Cambridge Institute for Medical Research, Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Robin Antrobus
- Cambridge Institute for Medical Research, Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - James C Williamson
- Cambridge Institute for Medical Research, Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Paul J Lehner
- Cambridge Institute for Medical Research, Department of Medicine, University of Cambridge, Cambridge, United Kingdom
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Maelfait J, Bridgeman A, Benlahrech A, Cursi C, Rehwinkel J. Restriction by SAMHD1 Limits cGAS/STING-Dependent Innate and Adaptive Immune Responses to HIV-1. Cell Rep 2016; 16:1492-1501. [PMID: 27477283 PMCID: PMC4978700 DOI: 10.1016/j.celrep.2016.07.002] [Citation(s) in RCA: 81] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Revised: 05/20/2016] [Accepted: 07/01/2016] [Indexed: 01/08/2023] Open
Abstract
SAMHD1 is a restriction factor for HIV-1 infection. SAMHD1 mutations cause the autoinflammatory Aicardi-Goutières syndrome that is characterized by chronic type I interferon (IFN) secretion. We show that the spontaneous IFN response in SAMHD1-deficient cells and mice requires the cGAS/STING cytosolic DNA-sensing pathway. We provide genetic evidence that cell-autonomous control of lentivirus infection in myeloid cells by SAMHD1 limits virus-induced production of IFNs and the induction of co-stimulatory markers. This program of myeloid cell activation required reverse transcription, cGAS and STING, and signaling through the IFN receptor. Furthermore, SAMHD1 reduced the induction of virus-specific cytotoxic T cells in vivo. Therefore, virus restriction by SAMHD1 limits the magnitude of IFN and T cell responses. This demonstrates a competition between cell-autonomous virus control and subsequent innate and adaptive immune responses, a concept with important implications for the treatment of infection. Spontaneous IFN production in SAMHD1-deficient cells requires cGAS and STING During HIV-1 infection, SAMHD1 limits activation of myeloid cells cGAS and STING detect HIV-1 infection in SAMHD1-deficient cells and induce IFN SAMHD1 prevents virus-specific CD8 T cell responses in vivo
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Affiliation(s)
- Jonathan Maelfait
- Medical Research Council Human Immunology Unit, Weatherall Institute of Molecular Medicine and Radcliffe Department of Medicine, University of Oxford, Oxford OX3 9DS, UK
| | - Anne Bridgeman
- Medical Research Council Human Immunology Unit, Weatherall Institute of Molecular Medicine and Radcliffe Department of Medicine, University of Oxford, Oxford OX3 9DS, UK
| | - Adel Benlahrech
- Medical Research Council Human Immunology Unit, Weatherall Institute of Molecular Medicine and Nuffield Department of Medicine, University of Oxford, Oxford OX3 9DS, UK
| | - Chiara Cursi
- Medical Research Council Human Immunology Unit, Weatherall Institute of Molecular Medicine and Radcliffe Department of Medicine, University of Oxford, Oxford OX3 9DS, UK
| | - Jan Rehwinkel
- Medical Research Council Human Immunology Unit, Weatherall Institute of Molecular Medicine and Radcliffe Department of Medicine, University of Oxford, Oxford OX3 9DS, UK.
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Daly MB, Roth ME, Bonnac L, Maldonado JO, Xie J, Clouser CL, Patterson SE, Kim B, Mansky LM. Dual anti-HIV mechanism of clofarabine. Retrovirology 2016; 13:20. [PMID: 27009333 PMCID: PMC4806454 DOI: 10.1186/s12977-016-0254-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Accepted: 03/17/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND HIV-1 replication kinetics inherently depends on the availability of cellular dNTPs for viral DNA synthesis. In activated CD4(+) T cells and other rapidly dividing cells, the concentrations of dNTPs are high and HIV-1 reverse transcription occurs in an efficient manner. In contrast, nondividing cells such as macrophages have lower dNTP pools, which restricts efficient reverse transcription. Clofarabine is an FDA approved ribonucleotide reductase inhibitor, which has shown potent antiretroviral activity in transformed cell lines. Here, we explore the potency, toxicity and mechanism of action of clofarabine in the human primary HIV-1 target cells: activated CD4(+) T cells and macrophages. RESULTS Clofarabine is a potent HIV-1 inhibitor in both activated CD4(+) T cells and macrophages. Due to its minimal toxicity in macrophages, clofarabine displays a selectivity index over 300 in this nondividing cell type. The anti-HIV-1 activity of clofarabine correlated with a significant decrease in both cellular dNTP levels and viral DNA synthesis. Additionally, we observed that clofarabine triphosphate was directly incorporated into DNA by HIV-1 reverse transcriptase and blocked processive DNA synthesis, particularly at the low dNTP levels found in macrophages. CONCLUSIONS Taken together, these data provide strong mechanistic evidence that clofarabine is a dual action inhibitor of HIV-1 replication that both limits dNTP substrates for viral DNA synthesis and directly inhibits the DNA polymerase activity of HIV-1 reverse transcriptase.
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Affiliation(s)
- Michele B Daly
- Center for Drug Discovery, Department of Pediatrics, Emory Center for AIDS Research, Emory University, Children's Healthcare of Atlanta, 1760 Haygood Dr., Atlanta, GA, 30322, USA
| | - Megan E Roth
- Institute for Molecular Virology, University of Minnesota, 18-242 Moos Tower, 515 Delaware St SE, Minneapolis, MN, 55455, USA.,Department of Diagnostic and Biological Sciences, School of Dentistry, University of Minnesota, Minneapolis, MN, 55455, USA.,Department of Microbiology and Immunology, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Laurent Bonnac
- Center for Drug Design, Academic Health Center, University of Minnesota, Minneapolis, MN, 55455, USA
| | - José O Maldonado
- Institute for Molecular Virology, University of Minnesota, 18-242 Moos Tower, 515 Delaware St SE, Minneapolis, MN, 55455, USA.,Department of Diagnostic and Biological Sciences, School of Dentistry, University of Minnesota, Minneapolis, MN, 55455, USA.,Department of Microbiology and Immunology, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Jiashu Xie
- Center for Drug Design, Academic Health Center, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Christine L Clouser
- Institute for Molecular Virology, University of Minnesota, 18-242 Moos Tower, 515 Delaware St SE, Minneapolis, MN, 55455, USA
| | - Steven E Patterson
- Center for Drug Design, Academic Health Center, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Baek Kim
- Center for Drug Discovery, Department of Pediatrics, Emory Center for AIDS Research, Emory University, Children's Healthcare of Atlanta, 1760 Haygood Dr., Atlanta, GA, 30322, USA.
| | - Louis M Mansky
- Institute for Molecular Virology, University of Minnesota, 18-242 Moos Tower, 515 Delaware St SE, Minneapolis, MN, 55455, USA. .,Department of Diagnostic and Biological Sciences, School of Dentistry, University of Minnesota, Minneapolis, MN, 55455, USA. .,Department of Microbiology and Immunology, University of Minnesota, Minneapolis, MN, 55455, USA. .,Center for Drug Design, Academic Health Center, University of Minnesota, Minneapolis, MN, 55455, USA.
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26
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Luo H. Interplay between the virus and the ubiquitin-proteasome system: molecular mechanism of viral pathogenesis. Curr Opin Virol 2015; 17:1-10. [PMID: 26426962 PMCID: PMC7102833 DOI: 10.1016/j.coviro.2015.09.005] [Citation(s) in RCA: 107] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Revised: 09/08/2015] [Accepted: 09/15/2015] [Indexed: 01/24/2023]
Abstract
Many viruses have evolved to utilize the host UPS for their own benefit. Viruses subvert the UPS to maintain optimal level/function of viral proteins. Viruses exploit the UPS to degrade host proteins which impede viral growth. The UPS serves as an important host anti-viral defense mechanism. The UPS is inhibited by some viruses to prevent viral clearance.
The ubiquitin–proteasome system (UPS) plays a central role in a wide range of fundamental cellular functions by ensuring protein quality control and through maintaining a critical level of important regulatory proteins. Viruses subvert or manipulate this cellular machinery to favor viral propagation and to evade host immune response. The UPS serves as a double-edged sword in viral pathogenesis: on the one hand, the UPS is utilized by many viruses to maintain proper function and level of viral proteins; while on the other hand, the UPS constitutes a host defense mechanism to eliminate viral components. To combat this host anti-viral machinery, viruses have evolved to employ the UPS to degrade or inactivate cellular proteins that limit viral growth. This review will highlight our current knowledge pertaining to the different roles for the UPS in viral pathogenesis.
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Affiliation(s)
- Honglin Luo
- Centre for Heart Lung Innovation, St. Paul's Hospital, Vancouver, BC, Canada; Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC, Canada.
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Abstract
UNLABELLED Monocyte-derived dendritic cells (MDDC) stimulate CD8 cytotoxic T lymphocytes (CTL) by presenting endogenous and exogenous viral peptides via major histocompatibility complex class I (MHC-I) molecules. MDDC are poorly susceptible to HIV-1, in part due to the presence of SAMHD1, a cellular enzyme that depletes intracellular deoxynucleoside triphosphates (dNTPs) and degrades viral RNA. Vpx, an HIV-2/SIVsm protein absent from HIV-1, antagonizes SAMHD1 by inducing its degradation. The impact of SAMHD1 on the adaptive cellular immune response remains poorly characterized. Here, we asked whether SAMHD1 modulates MHC-I-restricted HIV-1 antigen presentation. Untreated MDDC or MDDC pretreated with Vpx were exposed to HIV-1, and antigen presentation was examined by monitoring the activation of an HIV-1 Gag-specific CTL clone. SAMHD1 depletion strongly enhanced productive infection of MDDC as well as endogenous HIV-1 antigen presentation. Time-lapse microscopy analysis demonstrated that in the absence of SAMHD1, the CTL rapidly killed infected MDDC. We also report that various transmitted/founder (T/F) HIV-1 strains poorly infected MDDC and, as a consequence, did not stimulate CTL. Vesicular stomatitis virus glycoprotein (VSV-G) pseudotyping of T/F alleviated a block in viral entry and induced antigen presentation only in the absence of SAMHD1. Furthermore, by using another CTL clone that mostly recognizes incoming HIV-1 antigens, we demonstrate that SAMHD1 does not influence exogenous viral antigen presentation. Altogether, our results demonstrate that the antiviral activity of SAMHD1 impacts antigen presentation by DC, highlighting the link that exists between restriction factors and adaptive immune responses. IMPORTANCE Upon viral infection, DC may present antigens derived from incoming viral material in the absence of productive infection of DC or from newly synthesized viral proteins. In the case of HIV, productive infection of DC is blocked at an early postentry step. This is due to the presence of SAMHD1, a cellular enzyme that depletes intracellular levels of dNTPs and inhibits viral reverse transcription. We show that the depletion of SAMHD1 in DCs strongly stimulates the presentation of viral antigens derived from newly produced viral proteins, leading to the activation of HIV-1-specific cytotoxic T lymphocytes (CTL). We further show in real time that the enhanced activation of CTL leads to killing of infected DCs. Our results indicate that the antiviral activity of SAMHD1 not only impacts HIV replication but also impacts antigen presentation by DC. They highlight the link that exists between restriction factors and adaptive immune responses.
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28
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Hertoghs N, van der Aar AMG, Setiawan LC, Kootstra NA, Gringhuis SI, Geijtenbeek TBH. SAMHD1 degradation enhances active suppression of dendritic cell maturation by HIV-1. THE JOURNAL OF IMMUNOLOGY 2015; 194:4431-7. [PMID: 25825449 DOI: 10.4049/jimmunol.1403016] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Accepted: 02/26/2015] [Indexed: 11/19/2022]
Abstract
A hallmark of HIV-1 infection is the lack of sterilizing immunity. Dendritic cells (DCs) are crucial in the induction of immunity, and lack of DC activation might underlie the absence of an effective anti-HIV-1 response. We have investigated how HIV-1 infection affects maturation of DCs. Our data show that even though DCs are productively infected by HIV-1, infection does not induce DC maturation. HIV-1 infection actively suppresses DC maturation, as HIV-1 infection inhibited TLR-induced maturation of DCs and thereby decreased the immune stimulatory capacity of DCs. Interfering with SAMHD1 restriction further increased infection of DCs, but did not lead to DC maturation. Notably, higher infection observed with SAMHD1 depletion correlated with a stronger suppression of maturation. Furthermore, blocking reverse transcription rescued TLR-induced maturation. These data strongly indicate that HIV-1 replication does not trigger immune activation in DCs, but that HIV-1 escapes immune surveillance by actively suppressing DC maturation independent of SAMHD1. Elucidation of the mechanism of suppression can lead to promising targets for therapy or vaccine design.
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Affiliation(s)
- Nina Hertoghs
- Department of Experimental Immunology, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, the Netherlands; and
| | - Angelic M G van der Aar
- Department of Experimental Immunology, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, the Netherlands; and
| | - Laurentia C Setiawan
- Department of Experimental Immunology, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, the Netherlands; and Laboratory of Viral Immune Pathogenesis, Department of Experimental Immunology, Center for Infection and Immunity Amsterdam, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, the Netherlands
| | - Neeltje A Kootstra
- Department of Experimental Immunology, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, the Netherlands; and Laboratory of Viral Immune Pathogenesis, Department of Experimental Immunology, Center for Infection and Immunity Amsterdam, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, the Netherlands
| | - Sonja I Gringhuis
- Department of Experimental Immunology, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, the Netherlands; and
| | - Teunis B H Geijtenbeek
- Department of Experimental Immunology, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, the Netherlands; and
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29
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Zhu CF, Wei W, Peng X, Dong YH, Gong Y, Yu XF. The mechanism of substrate-controlled allosteric regulation of SAMHD1 activated by GTP. ACTA ACUST UNITED AC 2015; 71:516-24. [PMID: 25760601 DOI: 10.1107/s1399004714027527] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Accepted: 12/17/2014] [Indexed: 12/20/2022]
Abstract
SAMHD1 is the only known eukaryotic deoxynucleoside triphosphate triphosphohydrolase (dNTPase) and is a major regulator of intracellular dNTP pools. It has been reported to be a potent inhibitor of retroviruses such as HIV-1 and endogenous retrotransposons. Previous crystal structures have revealed that SAMHD1 is activated by dGTP-dependent tetramer formation. However, recent data have indicated that the primary activator of SAMHD1 is GTP, not dGTP. Therefore, how its dNTPase activity is regulated needs to be further clarified. Here, five crystal structures of the catalytic core of SAMHD1 in complex with different combinations of GTP and dNTPs are reported, including a GTP-bound dimer and four GTP/dNTP-bound tetramers. The data show that human SAMHD1 contains two unique activator-binding sites in the allosteric pocket. The primary activator GTP binds to one site and the substrate dNTP (dATP, dCTP, dUTP or dTTP) occupies the other. Consequently, both GTP and dNTP are required for tetramer activation of the enzyme. In the absence of substrate binding, SAMHD1 adopts an inactive dimer conformation even when complexed with GTP. Furthermore, SAMHD1 activation is regulated by the concentration of dNTP. Thus, the level of dNTP pools is elegantly regulated by the self-sensing ability of SAMHD1 through a novel activation mechanism.
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Affiliation(s)
- Chun Feng Zhu
- School of Life Sciences, Tianjin University, Tianjin, People's Republic of China
| | - Wei Wei
- School of Life Sciences, Tianjin University, Tianjin, People's Republic of China
| | - Xin Peng
- School of Life Sciences, Tianjin University, Tianjin, People's Republic of China
| | - Yu Hui Dong
- Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences, 19B Yuquan Road, Shijingshan District, Beijing 100049, People's Republic of China
| | - Yong Gong
- Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences, 19B Yuquan Road, Shijingshan District, Beijing 100049, People's Republic of China
| | - Xiao Fang Yu
- School of Life Sciences, Tianjin University, Tianjin, People's Republic of China
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Rigby RE, Rehwinkel J. RNA degradation in antiviral immunity and autoimmunity. Trends Immunol 2015; 36:179-88. [PMID: 25709093 PMCID: PMC4358841 DOI: 10.1016/j.it.2015.02.001] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Revised: 02/02/2015] [Accepted: 02/02/2015] [Indexed: 01/09/2023]
Abstract
The nonsense-mediated decay (NMD) pathway defends cells against RNA virus invasion. NMD targets viral RNAs for degradation, including by the RNA exosome. Genetic deficiencies in NMD and RNA exosome components cause autoimmunity. NMD and the RNA exosome prevent aberrant activation of innate immune responses.
Post-transcriptional control determines the fate of cellular RNA molecules. Nonsense-mediated decay (NMD) provides quality control of mRNA, targeting faulty cellular transcripts for degradation by multiple nucleases including the RNA exosome. Recent findings have revealed a role for NMD in targeting viral RNA molecules, thereby restricting virus infection. Interestingly, NMD is also linked to immune responses at another level: mutations affecting the NMD or RNA exosome machineries cause chronic activation of defence programmes, resulting in autoimmune phenotypes. Here we place these observations in the context of other links between innate antiviral immunity and type I interferon mediated disease and examine two models: one in which expression or function of pathogen sensors is perturbed and one wherein host-derived RNA molecules with a propensity to activate such sensors accumulate.
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Affiliation(s)
- Rachel E Rigby
- Medical Research Council Human Immunology Unit, Medical Research Council Weatherall Institute of Molecular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford OX3 9DS, 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 OX3 9DS, UK.
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31
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Chauveau L, Puigdomenech I, Ayinde D, Roesch F, Porrot F, Bruni D, Visseaux B, Descamps D, Schwartz O. HIV-2 infects resting CD4+ T cells but not monocyte-derived dendritic cells. Retrovirology 2015; 12:2. [PMID: 25582927 PMCID: PMC4307230 DOI: 10.1186/s12977-014-0131-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Accepted: 12/17/2014] [Indexed: 12/30/2022] Open
Abstract
Background Human Immunodeficiency Virus-type 2 (HIV-2) encodes Vpx that degrades SAMHD1, a cellular restriction factor active in non-dividing cells. HIV-2 replicates in lymphocytes but the susceptibility of monocyte-derived dendritic cells (MDDCs) to in vitro infection remains partly characterized. Results Here, we investigated HIV-2 replication in primary CD4+ T lymphocytes, both activated and non-activated, as well as in MDDCs. We focused on the requirement of Vpx for productive HIV-2 infection, using the reference HIV-2 ROD strain, the proviral clone GL-AN, as well as two primary HIV-2 isolates. All HIV-2 strains tested replicated in activated CD4+ T cells. Unstimulated CD4+ T cells were not productively infected by HIV-2, but viral replication was triggered upon lymphocyte activation in a Vpx-dependent manner. In contrast, MDDCs were poorly infected when exposed to HIV-2. HIV-2 particles did not potently fuse with MDDCs and did not lead to efficient viral DNA synthesis, even in the presence of Vpx. Moreover, the HIV-2 strains tested were not efficiently sensed by MDDCs, as evidenced by a lack of MxA induction upon viral exposure. Virion pseudotyping with VSV-G rescued fusion, productive infection and HIV-2 sensing by MDDCs. Conclusion Vpx allows the non-productive infection of resting CD4+ T cells, but does not confer HIV-2 with the ability to efficiently infect MDDCs. In these cells, an entry defect prevents viral fusion and reverse transcription independently of SAMHD1. We propose that HIV-2, like HIV-1, does not productively infect MDDCs, possibly to avoid triggering an immune response mediated by these cells. Electronic supplementary material The online version of this article (doi:10.1186/s12977-014-0131-7) contains supplementary material, which is available to authorized users.
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Lenzi GM, Domaoal RA, Kim DH, Schinazi RF, Kim B. Kinetic variations between reverse transcriptases of viral protein X coding and noncoding lentiviruses. Retrovirology 2014; 11:111. [PMID: 25524560 PMCID: PMC4282736 DOI: 10.1186/s12977-014-0111-y] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Accepted: 11/24/2014] [Indexed: 01/29/2023] Open
Abstract
Background Host SAM domain and HD domain-containing protein 1 (SAMHD1) suppresses reverse transcription kinetics of HIV-1 in nondividing cells such as macrophages by hydrolyzing and nearly depleting cellular dNTPs, which are the substrates of viral reverse transcriptase (RT). However, unlike HIV-1, HIV-2 and SIVsm encode viral protein X (Vpx), which counteracts the dNTPase activity of SAMHD1 and elevates dNTP concentration, allowing the viruses to replicate under abundant dNTP conditions even in nondividing cells. Findings Here we tested whether RTs of these Vpx coding and noncoding lentiviruses display different enzyme kinetic profiles in response to dNTP concentrations. For this test, we characterized an extensive collection of RTs from 7 HIV-1 strains, 4 HIV-2 strains and 7 SIV strains, and determined their steady-state kinetic parameters. The Km values of all HIV-1 RTs were consistently low and close to the low dNTP concentrations found in macrophages. However, the Km values of SIV and HIV-2 RTs were not only higher than those of HIV-1 RTs but also varied significantly, indicating that HIV-2/SIV RTs require higher dNTP concentrations for efficient DNA synthesis, compared to HIV-1 RT. However, the kcat values of all eighteen lentiviral RTs were very similar. Conclusions Our biochemical analysis supports the hypothesis that the enzymological properties, particularly, Km values, of lentivirus RTs, are mechanistically tied with the cellular dNTP availability in nondividing target cells, which is controlled by SAMHD1 and Vpx.
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Affiliation(s)
- Gina M Lenzi
- Center for Drug Discovery, Center for AIDS Research, Department of Pediatrics, Emory University School of Medicine, 1760 Haygood Drive, Atlanta, GA, USA.
| | - Robert A Domaoal
- Center for Drug Discovery, Center for AIDS Research, Department of Pediatrics, Emory University School of Medicine, 1760 Haygood Drive, Atlanta, GA, USA.
| | - Dong-Hyun Kim
- College of Pharmacy, Kyung-Hee University, Seoul, South Korea.
| | - Raymond F Schinazi
- Center for Drug Discovery, Center for AIDS Research, Department of Pediatrics, Emory University School of Medicine, 1760 Haygood Drive, Atlanta, GA, USA. .,Veterans Affairs Medical Center, Decatur, GA, USA.
| | - Baek Kim
- Center for Drug Discovery, Center for AIDS Research, Department of Pediatrics, Emory University School of Medicine, 1760 Haygood Drive, Atlanta, GA, USA. .,College of Pharmacy, Kyung-Hee University, Seoul, South Korea.
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Abstract
Macrophages are a diverse population of phagocytic cells that reside in tissues throughout the body. At sites of infection, macrophages encounter and engulf invading microbes. Accordingly, macrophages possess specialized effector functions to kill or coordinate the elimination of their prey. Nevertheless, many intracellular bacterial pathogens preferentially replicate inside macrophages. Here we consider explanations for what we call "the macrophage paradox:" why do so many pathogenic bacteria replicate in the very cells equipped to destroy them? We ask whether replication in macrophages is an unavoidable fate that essentially defines a key requirement to be a pathogen. Conversely, we consider whether fundamental aspects of macrophage biology provide unique cellular or metabolic environments that pathogens can exploit. We conclude that resolution of the macrophage paradox requires acknowledgment of the richness and complexity of macrophages as a replicative niche.
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Affiliation(s)
- Jordan V Price
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Russell E Vance
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA; Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, CA 94720, USA.
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Stevenson M. Role of myeloid cells in HIV-1-host interplay. J Neurovirol 2014; 21:242-8. [PMID: 25236811 DOI: 10.1007/s13365-014-0281-3] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2014] [Revised: 07/25/2014] [Accepted: 08/14/2014] [Indexed: 12/11/2022]
Abstract
The AIDS research field has embarked on a bold mission to cure HIV-1-infected individuals of the virus. To do so, scientists are attempting to identify the reservoirs that support viral persistence in patients on therapy, to understand how viral persistence is regulated and to come up with strategies that interrupt viral persistence and that eliminate the viral reservoirs. Most of the attention regarding the cure of HIV-1 infection has focused on the CD4+ T cell reservoir. Investigators are developing tools to probe the CD4+ T cell reservoirs as well as in vitro systems that provide clues on how to perturb them. By comparison, the myeloid cell, and in particular, the macrophage has received far less attention. As a consequence, there is very little understanding as to the role played by myeloid cells in viral persistence in HIV-1-infected individuals on suppressive therapy. As such, should myeloid cells constitute a viral reservoir, unique strategies may be required for their elimination. This article will overview research that is examining the role of macrophage in virus-host interplay and will discuss features of this interplay that could impact efforts to eliminate myeloid cell reservoirs.
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Affiliation(s)
- Mario Stevenson
- Department of Medicine, University of Miami Medical School, Miami, FL, USA,
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Zhu C, Gao W, Zhao K, Qin X, Zhang Y, Peng X, Zhang L, Dong Y, Zhang W, Li P, Wei W, Gong Y, Yu XF. Structural insight into dGTP-dependent activation of tetrameric SAMHD1 deoxynucleoside triphosphate triphosphohydrolase. Nat Commun 2014; 4:2722. [PMID: 24217394 DOI: 10.1038/ncomms3722] [Citation(s) in RCA: 93] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2013] [Accepted: 10/07/2013] [Indexed: 01/20/2023] Open
Abstract
SAMHD1 is a dGTP-activated deoxynucleoside triphosphate triphosphohydrolase (dNTPase) whose dNTPase activity has been linked to HIV/SIV restriction. The mechanism of its dGTP-activated dNTPase function remains unclear. Recent data also indicate that SAMHD1 regulates retrotransposition of LINE-1 elements. Here we report the 1.8-Å crystal structure of homotetrameric SAMHD1 in complex with the allosteric activator and substrate dGTP/dATP. The structure indicates the mechanism of dGTP-dependent tetramer formation, which requires the cooperation of three subunits and two dGTP/dATP molecules at each allosteric site. Allosteric dGTP binding induces conformational changes at the active site, allowing a more stable interaction with the substrate and explaining the dGTP-induced SAMHD1 dNTPase activity. Mutations of dGTP binding residues in the allosteric site affect tetramer formation, dNTPase activity and HIV-1 restriction. dGTP-triggered tetramer formation is also important for SAMHD1-mediated LINE-1 regulation. The structural and functional information provided here should facilitate future investigation of SAMHD1 function, including dNTPase activity, LINE-1 modulation and HIV-1 restriction.
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Affiliation(s)
- Chunfeng Zhu
- 1] School of Life Sciences, Tianjin University, Tianjin 300072, China [2]
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Carbonaro Sarracino D, Tarantal AF, Lee CCI, Martinez M, Jin X, Wang X, Hardee CL, Geiger S, Kahl CA, Kohn DB. Effects of vector backbone and pseudotype on lentiviral vector-mediated gene transfer: studies in infant ADA-deficient mice and rhesus monkeys. Mol Ther 2014; 22:1803-16. [PMID: 24925206 DOI: 10.1038/mt.2014.88] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2013] [Accepted: 05/11/2014] [Indexed: 01/05/2023] Open
Abstract
Systemic delivery of a lentiviral vector carrying a therapeutic gene represents a new treatment for monogenic disease. Previously, we have shown that transfer of the adenosine deaminase (ADA) cDNA in vivo rescues the lethal phenotype and reconstitutes immune function in ADA-deficient mice. In order to translate this approach to ADA-deficient severe combined immune deficiency patients, neonatal ADA-deficient mice and newborn rhesus monkeys were treated with species-matched and mismatched vectors and pseudotypes. We compared gene delivery by the HIV-1-based vector to murine γ-retroviral vectors pseudotyped with vesicular stomatitis virus-glycoprotein or murine retroviral envelopes in ADA-deficient mice. The vesicular stomatitis virus-glycoprotein pseudotyped lentiviral vectors had the highest titer and resulted in the highest vector copy number in multiple tissues, particularly liver and lung. In monkeys, HIV-1 or simian immunodeficiency virus vectors resulted in similar biodistribution in most tissues including bone marrow, spleen, liver, and lung. Simian immunodeficiency virus pseudotyped with the gibbon ape leukemia virus envelope produced 10- to 30-fold lower titers than the vesicular stomatitis virus-glycoprotein pseudotype, but had a similar tissue biodistribution and similar copy number in blood cells. The relative copy numbers achieved in mice and monkeys were similar when adjusted to the administered dose per kg. These results suggest that this approach can be scaled-up to clinical levels for treatment of ADA-deficient severe combined immune deficiency subjects with suboptimal hematopoietic stem cell transplantation options.
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Affiliation(s)
- Denise Carbonaro Sarracino
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, California, USA
| | - Alice F Tarantal
- 1] Center for Fetal Monkey Gene Transfer for Heart, Lung, and Blood Diseases, University of California, Davis, California USA [2] Departments of Pediatrics and Cell Biology and Human Anatomy, University of California, Davis, CA, USA
| | - C Chang I Lee
- Center for Fetal Monkey Gene Transfer for Heart, Lung, and Blood Diseases, University of California, Davis, California USA
| | - Michele Martinez
- Center for Fetal Monkey Gene Transfer for Heart, Lung, and Blood Diseases, University of California, Davis, California USA
| | - Xiangyang Jin
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, California, USA
| | - Xiaoyan Wang
- Department of General Internal Medicine and Health Services Research, University of California, Los Angeles California, USA
| | - Cinnamon L Hardee
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, California, USA
| | - Sabine Geiger
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, California, USA
| | - Christoph A Kahl
- 1] Division of Research Immunology/BMT, Children's Hospital Los Angeles, Los Angeles, California, USA [2] Current address: Oregon National Primate Research Center, Oregon Health and Science University, Beaverton, Oregon, USA
| | - Donald B Kohn
- 1] Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, California, USA [2] Department of Pediatrics, David Geffen School of Medicine, University of California, Los Angeles, California, USA
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Sze A, Belgnaoui SM, Olagnier D, Lin R, Hiscott J, van Grevenynghe J. Host restriction factor SAMHD1 limits human T cell leukemia virus type 1 infection of monocytes via STING-mediated apoptosis. Cell Host Microbe 2014; 14:422-34. [PMID: 24139400 DOI: 10.1016/j.chom.2013.09.009] [Citation(s) in RCA: 145] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2013] [Revised: 08/28/2013] [Accepted: 09/24/2013] [Indexed: 11/17/2022]
Abstract
Human T cell leukemia virus type 1 (HTLV-1) is the causative agent of adult T cell leukemia and HTLV-1-associated myelopathies. In addition to T cells, HTLV-1 infects cells of the myeloid lineage, which play critical roles in the host innate response to viral infection. Investigating the monocyte depletion observed during HTLV-1 infection, we discovered that primary human monocytes infected with HTLV-1 undergo abortive infection accompanied by apoptosis dependent on SAMHD1, a host restriction factor that hydrolyzes endogenous dNTPs to below the levels required for productive reverse transcription. Reverse transcription intermediates (RTI) produced in the presence of SAMHD1 induced IRF3-mediated antiviral and apoptotic responses. Viral RTIs complexed with the DNA sensor STING to trigger formation of an IRF3-Bax complex leading to apoptosis. This study provides a mechanistic explanation for abortive HTLV-1 infection of monocytes and reports a link between SAMHD1 restriction, HTLV-1 RTI sensing by STING, and initiation of IRF3-Bax driven apoptosis.
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Affiliation(s)
- Alexandre Sze
- Lady Davis Institute-Jewish General Hospital, McGill University, Montreal, QC H3T 1E2, Canada
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Mouse knockout models for HIV-1 restriction factors. Cell Mol Life Sci 2014; 71:3749-66. [PMID: 24854580 PMCID: PMC4160573 DOI: 10.1007/s00018-014-1646-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Revised: 04/24/2014] [Accepted: 05/05/2014] [Indexed: 12/21/2022]
Abstract
Infection of cells with human immunodeficiency virus 1 (HIV-1) is controlled by restriction factors, host proteins that counteract a variety of steps in the life cycle of this lentivirus. These include SAMHD1, APOBEC3G and tetherin, which block reverse transcription, hypermutate viral DNA and prevent progeny virus release, respectively. These and other HIV-1 restriction factors are conserved and have clear orthologues in the mouse. This review summarises studies in knockout mice lacking HIV-1 restriction factors. In vivo experiments in such animals have not only validated in vitro data obtained from cultured cells, but have also revealed new findings about the biology of these proteins. Indeed, genetic ablation of HIV-1 restriction factors in the mouse has provided evidence that restriction factors control retroviruses and other viruses in vivo and has led to new insights into the mechanisms by which these proteins counteract infection. For example, in vivo experiments in knockout mice demonstrate that virus control exerted by restriction factors can shape adaptive immune responses. Moreover, the availability of animals lacking restriction factors opens the possibility to study the function of these proteins in other contexts such as autoimmunity and cancer. Further in vivo studies of more recently identified HIV-1 restriction factors in gene targeted mice are, therefore, justified.
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Buitendijk M, Eszterhas SK, Howell AL. Toll-like receptor agonists are potent inhibitors of human immunodeficiency virus-type 1 replication in peripheral blood mononuclear cells. AIDS Res Hum Retroviruses 2014; 30:457-67. [PMID: 24328502 DOI: 10.1089/aid.2013.0199] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Innate immune responses to microbial pathogens are initiated following the binding of ligand to specific pattern recognition receptors. Each pattern recognition receptor, which includes members of the Toll-like receptor (TLR) family, is specific for a particular type of pathogen associated molecular pattern ensuring that the organism can respond rapidly to a wide range of pathogens including bacteria, viruses, and fungi. We studied the extent to which agonists to endosomal TLR could induce anti-HIV-1 activity in peripheral blood mononuclear cells (PBMCs). When agonists to TLR3, TLR7, TLR8 and TLR9 were added prior to infection with HIV-1, they significantly reduced infection of peripheral blood mononuclear cells. Interestingly, agonists to TLR8 and TLR9 were highly effective at blocking HIV replication even when added as late as 48 h or 72 h, respectively, after HIV-1 infection, indicating that the anti-viral effect was durable and long lasting. Analysis of the induction of anti-viral genes after agonist activation of TLR indicated that all of the agonists induced expression of the type I interferons and interferon stimulated genes, although to variable levels that depended on the agonist used. Interestingly, only the agonist to TLR9, ODN2395 DNA, induced expression of type II interferon and the anti-HIV proteins Apobec3G and SAMHD1. By blocking TLR activity using an inhibitor to the MyD88 adaptor protein, we demonstrated that, at least for TLR8 and TLR9, the anti-HIV activity was not entirely mediated by TLR activation, but likely by the activation of additional anti-viral sensors in HIV target cells. These findings suggest that agonists to the endosomal TLR function to induce expression of anti-HIV molecules by both TLR-mediated and non-TLR-mediated mechanisms. Moreover, the non-TLR-mediated mechanisms induced by these agonists could potentially be exploited to block HIV-1 replication in recently HIV-exposed individuals.
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Affiliation(s)
- Maarten Buitendijk
- Department of Veterans Affairs, Veterans Health Administration, Biomedical Laboratory Research and Development, White River Junction, Vermont
- Department of Physiology, Geisel School of Medicine at Dartmouth, Lebanon, New Hampshire
| | - Susan K. Eszterhas
- Department of Veterans Affairs, Veterans Health Administration, Biomedical Laboratory Research and Development, White River Junction, Vermont
- Department of Microbiology/Immunology, Geisel School of Medicine at Dartmouth, Lebanon, New Hampshire
| | - Alexandra L. Howell
- Department of Veterans Affairs, Veterans Health Administration, Biomedical Laboratory Research and Development, White River Junction, Vermont
- Department of Microbiology/Immunology, Geisel School of Medicine at Dartmouth, Lebanon, New Hampshire
- Department of Medicine, Geisel School of Medicine at Dartmouth, Lebanon, New Hampshire
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Abstract
Purpose of review To review recent published literature around three areas: long-term nonprogression/viral control; predictors of viral load set point/disease progression; and the potential impact of antiretroviral therapy (ART) in early HIV infection. Recent findings The natural course of untreated HIV infection varies widely with some HIV-positive individuals able to maintain high CD4 cell counts and/or suppressed viral load in the absence of ART. Although similar, the underlying mechanistic processes leading to long-term nonprogression and viral control are likely to differ. Concerted ongoing research efforts will hopefully identify host factors that are causally related to these phenotypes, thus providing opportunities for the development of novel treatment or preventive strategies. Although there is increasing evidence that initiation of ART during primary infection may prevent the immunological deterioration which would otherwise be seen in untreated HIV infection, recent studies do not address the longer term clinical benefits of ART at this very early stage. Summary A better understanding of the relative influences of viral, host, and environmental factors on the natural course of HIV infection has the potential to identify novel targets for intervention to prevent and treat HIV-infected persons.
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Variation of two primate lineage-specific residues in human SAMHD1 confers resistance to N terminus-targeted SIV Vpx proteins. J Virol 2013; 88:583-91. [PMID: 24173216 DOI: 10.1128/jvi.02866-13] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Sterile alpha motif and HD domain-containing protein 1 (SAMHD1) restricts human immunodeficiency virus type 1 (HIV-1) infection in myeloid cells but is inactivated by certain classes of simian immunodeficiency virus (SIV) Vpx proteins. Vpx proteins recruit the DCAF1-CRL4 E3 ubiquitin ligase to trigger species-specific SAMHD1 degradation. Determinants of SIV Vpx-mediated primate SAMHD1 degradation have been mapped to its C terminus. In this study, we have identified the N terminus of human SAMHD1 as a major species-specific determinant of Vpx-mediated suppression. The SIVmnd2 and SIVrcm Vpx proteins recognize the N terminus of rhesus, but not human, SAMHD1. We have also demonstrated that variation of two primate lineage-specific residues between human and rhesus SAMHD1 proteins determine resistance to SIVmnd2 and SIVrcm Vpx proteins. These residues (Cys15 and Ser52) are sequentially mutated to Phe in different lineages of Old World monkeys. Consequently, SIVmnd2 and SIVrcm Vpx proteins that could recognize Phe15- and Phe52-containing SAMHD1 could not inactivate human SAMHD1, which contains Cys15 and Ser52. In contrast, SIVmac Vpx, which targets the C terminus of SAMHD1 molecules, could inactivate various primate SAMHD1 molecules with divergent C-terminal sequences. Both C terminus-targeted SIVmac Vpx and N terminus-targeted SIVrcm Vpx require DCAF1 for the induction of SAMHD1 degradation. The ability of SIV Vpx to restrict SAMHD1 among different primate species is a manifestation of the SAMHD1 evolutionary pattern among those species.
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Rehwinkel J, Maelfait J, Bridgeman A, Rigby R, Hayward B, Liberatore RA, Bieniasz PD, Towers GJ, Moita LF, Crow YJ, Bonthron DT, Reis e Sousa C. SAMHD1-dependent retroviral control and escape in mice. EMBO J 2013; 32:2454-62. [PMID: 23872947 PMCID: PMC3770946 DOI: 10.1038/emboj.2013.163] [Citation(s) in RCA: 128] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Accepted: 07/01/2013] [Indexed: 12/12/2022] Open
Abstract
SAMHD1 is a host restriction factor for human immunodeficiency virus 1 (HIV-1) in cultured human cells. SAMHD1 mutations cause autoimmune Aicardi-Goutières syndrome and are found in cancers including chronic lymphocytic leukaemia. SAMHD1 is a triphosphohydrolase that depletes the cellular pool of deoxynucleoside triphosphates, thereby preventing reverse transcription of retroviral genomes. However, in vivo evidence for SAMHD1's antiviral activity has been lacking. We generated Samhd1 null mice that do not develop autoimmune disease despite displaying a type I interferon signature in spleen, macrophages and fibroblasts. Samhd1(-/-) cells have elevated deoxynucleoside triphosphate (dNTP) levels but, surprisingly, SAMHD1 deficiency did not lead to increased infection with VSV-G-pseudotyped HIV-1 vectors. The lack of restriction is likely attributable to the fact that dNTP concentrations in SAMHD1-sufficient mouse cells are higher than the KM of HIV-1 reverse transcriptase (RT). Consistent with this notion, an HIV-1 vector mutant bearing an RT with lower affinity for dNTPs was sensitive to SAMHD1-dependent restriction in cultured cells and in mice. This shows that SAMHD1 can restrict lentiviruses in vivo and that nucleotide starvation is an evolutionarily conserved antiviral mechanism.
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Affiliation(s)
- Jan Rehwinkel
- Immunobiology Laboratory, Cancer Research UK, London Research Institute, London, UK
- Medical Research Council Human Immunology Unit, Radcliffe Department of Medicine, Medical Research Council Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
| | - Jonathan Maelfait
- Medical Research Council Human Immunology Unit, Radcliffe Department of Medicine, Medical Research Council Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
| | - Anne Bridgeman
- Medical Research Council Human Immunology Unit, Radcliffe Department of Medicine, Medical Research Council Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
| | - Rachel Rigby
- Medical Research Council Human Immunology Unit, Radcliffe Department of Medicine, Medical Research Council Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
| | - Bruce Hayward
- Leeds Institute of Molecular Medicine, University of Leeds, St James’s University Hospital, Leeds, UK
| | - Rachel A Liberatore
- Laboratory of Retrovirology, Aaron Diamond AIDS Research Center, Howard Hughes Medical Institute, The Rockefeller University, New York, NY, USA
| | - Paul D Bieniasz
- Laboratory of Retrovirology, Aaron Diamond AIDS Research Center, Howard Hughes Medical Institute, The Rockefeller University, New York, NY, USA
| | - Greg J Towers
- Division of Infection and Immunity, University College London, London, UK
| | - Luis F Moita
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - Yanick J Crow
- Manchester Centre for Genomic Medicine, Manchester Academic Health Sciences Centre, University of Manchester, Manchester, UK
| | - David T Bonthron
- Leeds Institute of Molecular Medicine, University of Leeds, St James’s University Hospital, Leeds, UK
| | - Caetano Reis e Sousa
- Immunobiology Laboratory, Cancer Research UK, London Research Institute, London, UK
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43
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Restriction of virus infection but not catalytic dNTPase activity is regulated by phosphorylation of SAMHD1. J Virol 2013; 87:11516-24. [PMID: 23966382 DOI: 10.1128/jvi.01642-13] [Citation(s) in RCA: 127] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
SAMHD1 is a host protein responsible, at least in part, for the inefficient infection of dendritic, myeloid, and resting T cells by HIV-1. Interestingly, HIV-2 and SIVsm viruses are able to counteract SAMHD1 by targeting it for proteasomal degradation using their Vpx proteins. It has been proposed that SAMHD1 is a dGTP-dependent deoxynucleoside triphosphohydrolase (dNTPase) that restricts HIV-1 by reducing cellular dNTP levels to below that required for reverse transcription. However, nothing is known about SAMHD1 posttranslational modifications and their potential role in regulating SAMHD1 function. We used (32)P labeling and immunoblotting with phospho-specific antibodies to identify SAMHD1 as a phosphoprotein. Several amino acids in SAMHD1 were identified to be sites of phosphorylation using direct mass spectrometry. Mutation of these residues to alanine to prevent phosphorylation or to glutamic acid to mimic phosphorylation had no effect on the nuclear localization of SAMHD1 or its sensitivity to Vpx-mediated degradation. Furthermore, neither alanine nor glutamic acid substitutions had a significant effect on SAMHD1 dNTPase activity in an in vitro assay. Interestingly, however, we found that a T592E mutation, mimicking constitutive phosphorylation at a main phosphorylation site, severely affected the ability of SAMHD1 to restrict HIV-1 in a U937 cell-based restriction assay. In contrast, a T592A mutant was still capable of restricting HIV-1. These results indicate that SAMHD1 phosphorylation may be a negative regulator of SAMHD1 restriction activity. This conclusion is supported by our finding that SAMHD1 is hyperphosphorylated in monocytoid THP-1 cells under nonrestrictive conditions.
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Compton AA, Malik HS, Emerman M. Host gene evolution traces the evolutionary history of ancient primate lentiviruses. Philos Trans R Soc Lond B Biol Sci 2013; 368:20120496. [PMID: 23938749 DOI: 10.1098/rstb.2012.0496] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Simian immunodeficiency viruses (SIVs) have infected primate species long before human immunodeficiency virus has infected humans. Dozens of species-specific lentiviruses are found in African primate species, including two strains that have repeatedly jumped into human populations within the past century. Traditional phylogenetic approaches have grossly underestimated the age of these primate lentiviruses. Instead, here we review how selective pressures imposed by these viruses have fundamentally altered the evolutionary trajectory of hosts genes and, even in cases where there now remains no trace of the viruses themselves, these evolutionary signatures can reveal the types of viruses that were once present. Examination of selection by ancient viruses on the adaptive evolution of host genes has been used to derive minimum age estimates for modern primate lentiviruses. This type of data suggests that ancestors of modern SIV existed in simian primates more than 10 Ma. Moreover, examples of host resistance and viral adaptation have implications not only for estimating the age and host range of ancient primate lentiviruses, but also the pathogenic potential of their modern counterparts.
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Affiliation(s)
- Alex A Compton
- Molecular and Cellular Biology Graduate Program, University of Washington, , Seattle, WA 98195, USA
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45
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Abstract
Replication of HIV-1 and other retroviruses is dependent on numerous host proteins in the cells. Some of the host proteins, however, function as restriction factors to block retroviral infection of target cells. The host protein SAMHD1 has been identified as the first mammalian deoxynucleoside triphosphate triphosphohydrolase (dNTPase), which blocks the infection of HIV-1 and other retroviruses in non-cycling immune cells. SAMHD1 protein is highly expressed in human myeloid-lineage cells and CD4+ T-lymphocytes, but its retroviral restriction function is only observed in noncycling cells. Recent studies have revealed biochemical mechanisms of SAMHD1-mediated retroviral restriction. In this review, the latest progress on SAMHD1 research is summarized and the mechanisms by which SAMHD1 mediates retroviral restriction are analyzed. Although the physiological function of SAMHD1 is largely unknown, this review provides perspectives about the role of endogenous SAMHD1 protein in maintaining normal cellular function, such as nucleic acid metabolism and the proliferation of cells.
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46
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Identification of critical regions in human SAMHD1 required for nuclear localization and Vpx-mediated degradation. PLoS One 2013; 8:e66201. [PMID: 23874389 PMCID: PMC3708934 DOI: 10.1371/journal.pone.0066201] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2013] [Accepted: 05/02/2013] [Indexed: 01/19/2023] Open
Abstract
The sterile alpha motif (SAM) and HD domain-containing protein-1 (SAMHD1) inhibits the infection of resting CD4+ T cells and myeloid cells by human and related simian immunodeficiency viruses (HIV and SIV). Vpx inactivates SAMHD1 by promoting its proteasome-dependent degradation through an interaction with CRL4 (DCAF1) E3 ubiquitin ligase and the C-terminal region of SAMHD1. However, the determinants in SAMHD1 that are required for Vpx-mediated degradation have not been well characterized. SAMHD1 contains a classical nuclear localization signal (NLS), and NLS point mutants are cytoplasmic and resistant to Vpx-mediated degradation. Here, we demonstrate that NLS-mutant SAMHD1 K11A can be rescued by wild-type SAMHD1, restoring its nuclear localization; consequently, SAMHD1 K11A became sensitive to Vpx-mediated degradation in the presence of wild-type SAMHD1. Surprisingly, deletion of N-terminal regions of SAMHD1, including the classical NLS, generated mutant SAMHD1 proteins that were again sensitive to Vpx-mediated degradation. Unlike SAMHD1 K11A, these deletion mutants could be detected in the nucleus. Interestingly, NLS-defective SAMHD1 could still bind to karyopherin-β1 and other nuclear proteins. We also determined that the linker region between the SAM and HD domain and the HD domain itself is important for Vpx-mediated degradation but not Vpx interaction. Thus, SAMHD1 contains an additional nuclear targeting mechanism in addition to the classical NLS. Our data indicate that multiple regions in SAMHD1 are critical for Vpx-mediated nuclear degradation and that association with Vpx is not sufficient for Vpx-mediated degradation of SAMHD1. Since the linker region and HD domain may be involved in SAMHD1 multimerization, our results suggest that SAMHD1 multimerization may be required for Vpx-mediation degradation.
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47
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Côté SC, Plante A, Tardif MR, Tremblay MJ. Dectin-1/TLR2 and NOD2 agonists render dendritic cells susceptible to infection by X4-using HIV-1 and promote cis-infection of CD4(+) T cells. PLoS One 2013; 8:e67735. [PMID: 23844079 PMCID: PMC3699635 DOI: 10.1371/journal.pone.0067735] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Accepted: 05/22/2013] [Indexed: 11/18/2022] Open
Abstract
HIV-1 pathogenesis is intimately linked with microbial infections and innate immunity during all stages of the disease. While the impact of microbial-derived products in transmission of R5-using virus to CD4+ T cells by dendritic cells (DCs) has been addressed before, very limited data are available on the effect of such compounds on DC-mediated dissemination of X4-tropic variant. Here, we provide evidence that treatment of DCs with dectin-1/TLR2 and NOD2 ligands increases cis-infection of autologous CD4+ T cells by X4-using virus. This phenomenon is most likely associated with an enhanced permissiveness of DCs to productive infection with X4 virus, which is linked to increased surface expression of CXCR4 and the acquisition of a maturation profile by DCs. The ensuing DC maturation enhances susceptibility of CD4+ T cells to productive infection with HIV-1. This study highlights the crucial role of DCs at different stages of HIV-1 infection and particularly in spreading of viral strains displaying a X4 phenotype.
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Affiliation(s)
- Sandra C. Côté
- Axe des Maladies Infectieuses et Immunitaires, Centre Hospitalier Universitaire de Québec-Pavillon CHUL, Québec, Canada
| | - Audrey Plante
- Axe des Maladies Infectieuses et Immunitaires, Centre Hospitalier Universitaire de Québec-Pavillon CHUL, Québec, Canada
| | - Mélanie R. Tardif
- Axe des Maladies Infectieuses et Immunitaires, Centre Hospitalier Universitaire de Québec-Pavillon CHUL, Québec, Canada
| | - Michel J. Tremblay
- Axe des Maladies Infectieuses et Immunitaires, Centre Hospitalier Universitaire de Québec-Pavillon CHUL, Québec, Canada
- Département de Microbiologie-Infectiologie et Immunologie, Faculté de médecine, Université Laval, Québec, Canada
- * E-mail:
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48
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de Silva S, Hoy H, Hake TS, Wong HK, Porcu P, Wu L. Promoter methylation regulates SAMHD1 gene expression in human CD4+ T cells. J Biol Chem 2013; 288:9284-92. [PMID: 23426363 DOI: 10.1074/jbc.m112.447201] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The retrovirus restriction factor SAMHD1 is the first identified mammalian dNTP triphosphohydrolase that is highly expressed in human myeloid lineage cells and CD4(+) T lymphocytes. Although SAMHD1 expression is variable in human cell lines and tissue types, mechanisms underlying SAMHD1 gene regulation have not been defined. Recent studies showed that SAMHD1 is highly expressed in human primary CD4(+) T lymphocytes, but not in some CD4(+) T cell lines. Here, we report that SAMHD1 expression varies among four CD4(+) T cell lines and is transcriptionally regulated. Cloning and sequence analysis of the human SAMHD1 promoter revealed a CpG island that is methylated in CD4(+) T cell lines (such as Jurkat and Sup-T1), resulting in transcriptional repression of SAMHD1. We also found that the SAMHD1 promoter is unmethylated in primary CD4(+) T lymphocytes, which express high levels of SAMHD1, indicating a direct correlation between the methylation of the SAMHD1 promoter and transcriptional repression. SAMHD1 expression was induced in CD4(+) T cell lines by blocking DNA methyltransferase activity, suggesting that promoter methylation is one of the key epigenetic mechanisms by which SAMHD1 expression is regulated.
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Affiliation(s)
- Suresh de Silva
- Center for Retrovirus Research, Department of Veterinary Biosciences, The OhioState University, Columbus, OH 43210, USA
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49
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Abstract
Primate immunodeficiency viruses are highly specialized lentiviruses that have evolved to successfully infect and persist for the lifetime of the host. Despite encountering numerous potent antiviral factors, HIVs and SIVs are successful pathogens due to the acquisition of equally potent countermeasures in the form of accessory genes. The accessory gene Vpx encoded by HIV-2 and a subset of SIVs have a profound effect on the ability of lentiviruses to infect non-dividing cells, such as macrophages. Although most virus replication occurs in activated CD4(+) T cells, myeloid lineage cells are natural targets of infection and play a central role in virus transmission, dissemination, and persistence. However, myeloid lineage cells are poorly sensitive to lentiviral infection due partly to the high-level expression of a host protein that regulates nucleic acid metabolism named SAMHD1. Degradation of SAMHD1 is induced by Vpx to eliminate this intrinsic antiviral factor. Importantly, SAMHD1 has also been implicated as a negative regulator of the innate immune response, so the interplay between SAMHD1 and Vpx is likely to have significant consequences for virus replication, persistence, and immune control.
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Affiliation(s)
- Mark Sharkey
- University of Miami Miller School of Medicine, Miami, FL 33136, USA.
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SAMHD1 restricts HIV-1 cell-to-cell transmission and limits immune detection in monocyte-derived dendritic cells. J Virol 2012; 87:2846-56. [PMID: 23269793 DOI: 10.1128/jvi.02514-12] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
SAMHD1 is a viral restriction factor expressed in dendritic cells and other cells, inhibiting infection by cell-free human immunodeficiency virus type 1 (HIV-1) particles. SAMHD1 depletes the intracellular pool of deoxynucleoside triphosphates, thus impairing HIV-1 reverse transcription and productive infection in noncycling cells. The Vpx protein from HIV-2 or simian immunodeficiency virus (SIVsm/SIVmac) antagonizes the effect of SAMHD1 by triggering its degradation. A large part of HIV-1 spread occurs through direct contacts between infected cells and bystander target cells. Here, we asked whether SAMHD1 impairs direct HIV-1 transmission from infected T lymphocytes to monocyte-derived dendritic cells (MDDCs). HIV-1-infected lymphocytes were cocultivated with MDDCs that have been pretreated or not with Vpx or with small interfering RNA against SAMHD1. We show that in the cocultures, SAMHD1 significantly inhibits productive cell-to-cell transmission to target MDDCs and prevents the type I interferon response and expression of the interferon-stimulated gene MxA. Therefore, SAMHD1, by controlling the sensitivity of MDDCs to HIV-1 infection during intercellular contacts, impacts their ability to sense the virus and to trigger an innate immune response.
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