101
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Kozak CA. Origins of the endogenous and infectious laboratory mouse gammaretroviruses. Viruses 2014; 7:1-26. [PMID: 25549291 PMCID: PMC4306825 DOI: 10.3390/v7010001] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2014] [Accepted: 12/18/2014] [Indexed: 01/07/2023] Open
Abstract
The mouse gammaretroviruses associated with leukemogenesis are found in the classical inbred mouse strains and in house mouse subspecies as infectious exogenous viruses (XRVs) and as endogenous retroviruses (ERVs) inserted into their host genomes. There are three major mouse leukemia virus (MuLV) subgroups in laboratory mice: ecotropic, xenotropic, and polytropic. These MuLV subgroups differ in host range, pathogenicity, receptor usage and subspecies of origin. The MuLV ERVs are recent acquisitions in the mouse genome as demonstrated by the presence of many full-length nondefective MuLV ERVs that produce XRVs, the segregation of these MuLV subgroups into different house mouse subspecies, and by the positional polymorphism of these loci among inbred strains and individual wild mice. While some ecotropic and xenotropic ERVs can produce XRVs directly, others, especially the pathogenic polytropic ERVs, do so only after recombinations that can involve all three ERV subgroups. Here, I describe individual MuLV ERVs found in the laboratory mice, their origins and geographic distribution in wild mouse subspecies, their varying ability to produce infectious virus and the biological consequences of this expression.
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102
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CMV-promoter driven codon-optimized expression alters the assembly type and morphology of a reconstituted HERV-K(HML-2). Viruses 2014; 6:4332-45. [PMID: 25393897 PMCID: PMC4246225 DOI: 10.3390/v6114332] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Revised: 09/20/2014] [Accepted: 10/31/2014] [Indexed: 11/16/2022] Open
Abstract
The HERV-K(HML-2) family contains the most recently integrated and best preserved endogenized proviral sequences in the human genome. All known elements have nevertheless been subjected to mutations or deletions that render expressed particles non-infectious. Moreover, these post-insertional mutations hamper the analysis of the general biological properties of this ancient virus family. The expression of consensus sequences and sequences of elements with reverted post-insertional mutations has therefore been very instrumental in overcoming this limitation. We investigated the particle morphology of a recently reconstituted HERV-K113 element termed oriHERV-K113 using thin-section electron microscopy (EM) and could demonstrate that strong overexpression by substitution of the 5'LTR for a CMV promoter and partial codon optimization altered the virus assembly type and morphology. This included a conversion from the regular C-type to an A-type morphology with a mass of cytoplasmic immature cores tethered to the cell membrane and the membranes of vesicles. Overexpression permitted the release and maturation of virions but reduced the envelope content. A weaker boost of virus expression by Staufen-1 was not sufficient to induce these morphological alterations.
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103
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Soni C, Wong EB, Domeier PP, Khan TN, Satoh T, Akira S, Rahman ZSM. B cell-intrinsic TLR7 signaling is essential for the development of spontaneous germinal centers. THE JOURNAL OF IMMUNOLOGY 2014; 193:4400-14. [PMID: 25252960 DOI: 10.4049/jimmunol.1401720] [Citation(s) in RCA: 116] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Spontaneous germinal center (Spt-GC) B cells and follicular helper T cells generate high-affinity autoantibodies that are involved in the development of systemic lupus erythematosus. TLRs play a pivotal role in systemic lupus erythematosus pathogenesis. Although previous studies focused on the B cell-intrinsic role of TLR-MyD88 signaling on immune activation, autoantibody repertoire, and systemic inflammation, the mechanisms by which TLRs control the formation of Spt-GCs remain unclear. Using nonautoimmune C57BL/6 (B6) mice deficient in MyD88, TLR2, TLR3, TLR4, TLR7, or TLR9, we identified B cell-intrinsic TLR7 signaling as a prerequisite to Spt-GC formation without the confounding effects of autoimmune susceptibility genes and the overexpression of TLRs. TLR7 deficiency also rendered autoimmune B6.Sle1b mice unable to form Spt-GCs, leading to markedly decreased autoantibodies. Conversely, B6.yaa and B6.Sle1b.yaa mice expressing an extra copy of TLR7 and B6.Sle1b mice treated with a TLR7 agonist had increased Spt-GCs and follicular helper T cells. Further, TLR7/MyD88 deficiency led to compromised B cell proliferation and survival after B cell stimulation both in vitro and in vivo. In contrast, TLR9 inhibited Spt-GC development. Our findings demonstrate an absolute requirement for TLR7 and a negative regulatory function for TLR9 in Spt-GC formation under nonautoimmune and autoimmune conditions. Our data suggest that, under nonautoimmune conditions, Spt-GCs initiated by TLR7 produce protective Abs. However, in the presence of autoimmune susceptibility genes, TLR7-dependent Spt-GCs produce pathogenic autoantibodies. Thus, a single copy of TLR7 in B cells is the minimal requirement for breaking the GC-tolerance checkpoint.
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Affiliation(s)
- Chetna Soni
- Department of Microbiology and Immunology, Pennsylvania State University College of Medicine, Hershey, PA 17033
| | - Eric B Wong
- Department of Microbiology and Immunology, Pennsylvania State University College of Medicine, Hershey, PA 17033
| | - Phillip P Domeier
- Department of Microbiology and Immunology, Pennsylvania State University College of Medicine, Hershey, PA 17033
| | - Tahsin N Khan
- Department of Microbiology and Immunology, Pennsylvania State University College of Medicine, Hershey, PA 17033; Department of Molecular Microbiology and Immunology, Oregon Health and Science University, Portland, OR 97239; and
| | - Takashi Satoh
- Department of Host Defense, Research Institute for Microbial Diseases, Osaka University, Osaka 565-0871, Japan
| | - Shizuo Akira
- Department of Host Defense, Research Institute for Microbial Diseases, Osaka University, Osaka 565-0871, Japan
| | - Ziaur S M Rahman
- Department of Microbiology and Immunology, Pennsylvania State University College of Medicine, Hershey, PA 17033;
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104
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Nelson PN, Roden D, Nevill A, Freimanis GL, Trela M, Ejtehadi HD, Bowman S, Axford J, Veitch AM, Tugnet N, Rylance PB. Rheumatoid Arthritis is Associated with IgG Antibodies to Human Endogenous Retrovirus Gag Matrix: A Potential Pathogenic Mechanism of Disease? J Rheumatol 2014; 41:1952-60. [DOI: 10.3899/jrheum.130502] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Objective.Human endogenous retrovirus (HERV)-K10 has been implicated in the etiology and pathogenesis of rheumatoid arthritis (RA). A secondary immune response to this virus might suggest an antigen-driven response in patients. The Gag region of HERV-K10 could provide a key epitope important for immunological reactivity. We investigated the presence of IgG antibodies to this region and assessed its significance in RA.Methods.We determined an antigenic peptide on the matrix segment of HERV-K10 and developed an ELISA system to detect IgG antibodies in patients with RA and controls. The presence of antibodies to the matrix peptide (denoted as MAG1: RIGKELKQAGRKGNI) was correlated with patient details.Results.On screening patients’ serum, we found a significantly higher mean IgG antibody response to MAG1 in 30 patients with RA as compared to 23 patients with inflammatory bowel disease (p = 0.003), 29 patients with osteoarthritis (p = 0.001), and 43 healthy individuals (p = 0.002). Reactivity was not observed to a control peptide possessing a nonhomologous amino acid sequence. On evaluating clinical details with serological activity, no correlation with disease duration (p = 0.128), sex (p = 0.768), or rheumatoid factor status (p = 0.576) was found.Conclusion.A significantly elevated IgG antibody response to an HERV-K10 Gag matrix peptide was observed in patients with RA, suggesting that the exposure of HERV-K10 may cause a secondary, antigenic driven immune response in RA.
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105
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Johnson RM, Papp E, Grandal I, Kowalski PE, Nutter L, Wong RCC, Joseph-George AM, Danska JS, Guidos CJ. MuLV-related endogenous retroviral elements and Flt3 participate in aberrant end-joining events that promote B-cell leukemogenesis. Genes Dev 2014; 28:1179-90. [PMID: 24888589 PMCID: PMC4052764 DOI: 10.1101/gad.240820.114] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
During V(D)J recombination of immunoglobulin genes, p53 and nonhomologous end-joining (NHEJ) suppress aberrant rejoining of DNA double-strand breaks induced by recombinase-activating genes (Rags)-1/2. However, Rag deficiency does not prevent B-cell leukemogenesis in p53/NHEJ mutant mice. Johnson et al. identified a novel class of activating mutations in Flt3 in Rag/p53/NHEJ triple-mutant B-cell leukemias. These mutant Flt3 alleles were created by complex genomic rearrangements with Moloney leukemia virus (MuLV)-related endogenous retroviral (ERV) elements. Mutant Flt3 induced ligand-independent STAT5 phosphorylation and promoted development of clinically aggressive B-cell leukemia. During V(D)J recombination of immunoglobulin genes, p53 and nonhomologous end-joining (NHEJ) suppress aberrant rejoining of DNA double-strand breaks induced by recombinase-activating genes (Rags)-1/2, thus maintaining genomic stability and limiting malignant transformation during B-cell development. However, Rag deficiency does not prevent B-cell leukemogenesis in p53/NHEJ mutant mice, revealing that p53 and NHEJ also suppress Rag-independent mechanisms of B-cell leukemogenesis. Using several cytogenomic approaches, we identified a novel class of activating mutations in Fms-like tyrosine kinase 3 (Flt3), a receptor tyrosine kinase important for normal hematopoiesis in Rag/p53/NHEJ triple-mutant (TM) B-cell leukemias. These mutant Flt3 alleles were created by complex genomic rearrangements with Moloney leukemia virus (MuLV)-related endogenous retroviral (ERV) elements, generating ERV-Flt3 fusion genes encoding an N-terminally truncated mutant form of Flt3 (trFlt3) that was transcribed from ERV long terminal repeats. trFlt3 protein lacked most of the Flt3 extracellular domain and induced ligand-independent STAT5 phosphorylation and proliferation of hematopoietic progenitor cells. Furthermore, expression of trFlt3 in p53/NHEJ mutant hematopoietic progenitor cells promoted development of clinically aggressive B-cell leukemia. Thus, repetitive MuLV-related ERV sequences can participate in aberrant end-joining events that promote development of aggressive B-cell leukemia.
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Affiliation(s)
- Radia M Johnson
- Program in Developmental and Stem Cell Biology, Hospital for Sick Children Research Institute, Toronto, Ontario M5G 0A4, Canada; Department of Immunology
| | - Eniko Papp
- Program in Developmental and Stem Cell Biology, Hospital for Sick Children Research Institute, Toronto, Ontario M5G 0A4, Canada; Department of Medical Biophysics, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Ildiko Grandal
- Program in Developmental and Stem Cell Biology, Hospital for Sick Children Research Institute, Toronto, Ontario M5G 0A4, Canada
| | - Paul E Kowalski
- Program in Developmental and Stem Cell Biology, Hospital for Sick Children Research Institute, Toronto, Ontario M5G 0A4, Canada
| | - Lauryl Nutter
- Program in Developmental and Stem Cell Biology, Hospital for Sick Children Research Institute, Toronto, Ontario M5G 0A4, Canada
| | - Raymond C C Wong
- The Centre for Applied Genomics, Hospital for Sick Children Research Institute, Toronto, Ontario M5G 0A4, Canada
| | - Ann M Joseph-George
- The Centre for Applied Genomics, Hospital for Sick Children Research Institute, Toronto, Ontario M5G 0A4, Canada; Program in Genetics and Genome Biology, Hospital for Sick Children Research Institute, Toronto, Ontario M5G 0A4, Canada
| | - Jayne S Danska
- Department of Immunology, Department of Medical Biophysics, University of Toronto, Toronto, Ontario M5S 1A8, Canada; Program in Genetics and Genome Biology, Hospital for Sick Children Research Institute, Toronto, Ontario M5G 0A4, Canada
| | - Cynthia J Guidos
- Program in Developmental and Stem Cell Biology, Hospital for Sick Children Research Institute, Toronto, Ontario M5G 0A4, Canada; Department of Immunology
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106
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Abstract
Multiple intracellular RNA sensing innate immune pathways have been linked to autoimmune disease. RNA-related ligands taken up by the endocytic pathway activate TLRs, and affect primarily immune cells. This type of activation is enhanced by nucleic acid-specific antibodies and induces an inflammatory program. In contrast, spontaneous activation of cytoplasmic RNA sensing pathways targets mostly non-hematopoietic tissues and their effect on autoimmune disease is secondary to the release of interferon in the circulation. The fact that pathologies result from spontaneous activation of innate pathways implies that endogenous RNA ligands that might be sensed as pathogenic are commonly found in both immune and non-immune cells.
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107
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Virgin HW. The virome in mammalian physiology and disease. Cell 2014; 157:142-50. [PMID: 24679532 DOI: 10.1016/j.cell.2014.02.032] [Citation(s) in RCA: 398] [Impact Index Per Article: 39.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2014] [Revised: 02/13/2014] [Accepted: 02/13/2014] [Indexed: 02/07/2023]
Abstract
The virome contains the most abundant and fastest mutating genetic elements on Earth. The mammalian virome is constituted of viruses that infect host cells, virus-derived elements in our chromosomes, and viruses that infect the broad array of other types of organisms that inhabit us. Virome interactions with the host cannot be encompassed by a monotheistic view of viruses as pathogens. Instead, the genetic and transcriptional identity of mammals is defined in part by our coevolved virome, a concept with profound implications for understanding health and disease.
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Affiliation(s)
- Herbert W Virgin
- Department of Pathology and Immunology, Washington University School of Medicine, Campus Box 8118, 660 South Euclid Avenue, St. Louis, MO 63110, USA.
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108
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Endogenous retrovirus induces leukemia in a xenograft mouse model for primary myelofibrosis. Proc Natl Acad Sci U S A 2014; 111:8595-600. [PMID: 24912157 DOI: 10.1073/pnas.1401215111] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The compound immunodeficiencies in nonobese diabetic (NOD) inbred mice homozygous for the Prkdc(scid) and Il2rg(null) alleles (NSG mice) permit engraftment of a wide-range of primary human cells, enabling sophisticated modeling of human disease. In studies designed to define neoplastic stem cells of primary myelofibrosis (PMF), a myeloproliferative neoplasm characterized by profound disruption of the hematopoietic microenvironment, we observed a high frequency of acute myeloid leukemia (AML) in NSG mice. AML was of mouse origin, confined to PMF-xenografted mice, and contained multiple clonal integrations of ecotropic murine leukemia virus (E-MuLV). Significantly, MuLV replication was not only observed in diseased mice, but also in nontreated NSG controls. Furthermore, in addition to the single ecotropic endogenous retrovirus (eERV) located on chromosome 11 (Emv30) in the NOD genome, multiple de novo germ-line eERV integrations were observed in mice from each of four independent NSG mouse colonies. Analysis confirmed that E-MuLV originated from the Emv30 provirus and that recombination events were not necessary for virus replication or AML induction. Pathogenicity is thus likely attributable to PMF-mediated paracrine stimulation of mouse myeloid cells, which serve as targets for retroviral infection and transformation, as evidenced by integration into the Evi1 locus, a hotspot for retroviral-induced myeloid leukemia. This study thus corroborates a role of paracrine stimulation in PMF disease progression, underlines the importance of target cell type and numbers in MuLV-induced disease, and mandates awareness of replicating MuLV in NOD immunodeficient mice, which can significantly influence experimental results and their interpretation.
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109
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Colak E, Leslie A, Zausmer K, Khatamzas E, Kubarenko AV, Pichulik T, Klimosch SN, Mayer A, Siggs O, Hector A, Fischer R, Klesser B, Rautanen A, Frank M, Hill AVS, Manoury B, Beutler B, Hartl D, Simmons A, Weber ANR. RNA and imidazoquinolines are sensed by distinct TLR7/8 ectodomain sites resulting in functionally disparate signaling events. THE JOURNAL OF IMMUNOLOGY 2014; 192:5963-73. [PMID: 24813206 DOI: 10.4049/jimmunol.1303058] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
TLRs 7 and 8 are pattern recognition receptors controlling antiviral host defense or autoimmune diseases. Apart from foreign and host RNA, synthetic RNA oligoribonucleotides (ORN) or small molecules of the imidazoquinoline family activate TLR7 and 8 and are being developed as therapeutic agonists. The structure-function relationships for RNA ORN and imidazoquinoline sensing and consequent downstream signaling by human TLR7 and TLR8 are unknown. Proteome- and genome-wide analyses in primary human monocyte-derived dendritic cells here showed that TLR8 sensing of RNA ORN versus imidazoquinoline translates to ligand-specific differential phosphorylation and transcriptional events. In addition, TLR7 and 8 ectodomains were found to discriminate between RNA ORN and imidazoquinolines by overlapping and nonoverlapping recognition sites to which murine loss-of-function mutations and human naturally occurring hyporesponsive polymorphisms map. Our data suggest TLR7 and TLR8 can signal in two different "modes" depending on the class of ligand. Considering RNA ORN and imidazoquinolines have been regarded as functionally interchangeable, our study highlights important functional incongruities whose understanding will be important for developing TLR7 or 8 therapeutics with desirable effector and safety profiles for in vivo application.
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Affiliation(s)
- Elif Colak
- Junior Research Group Toll-Like Receptors and Cancer, German Cancer Research Center, 69120 Heidelberg, Germany
| | - Alasdair Leslie
- Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, United Kingdom;
| | - Kieran Zausmer
- Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, United Kingdom
| | - Elham Khatamzas
- Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, United Kingdom
| | - Andriy V Kubarenko
- Junior Research Group Toll-Like Receptors and Cancer, German Cancer Research Center, 69120 Heidelberg, Germany
| | - Tica Pichulik
- Department of Immunology, Interfaculty Institute for Cell Biology, University of Tübingen, 72076 Tübingen, Germany
| | - Sascha N Klimosch
- Department of Immunology, Interfaculty Institute for Cell Biology, University of Tübingen, 72076 Tübingen, Germany
| | - Alice Mayer
- Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, United Kingdom
| | - Owen Siggs
- Department of Genetics, The Scripps Research Institute, La Jolla, CA 92037
| | - Andreas Hector
- Department of Pediatrics I, University of Tübingen, 72076 Tübingen, Germany
| | - Roman Fischer
- Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, United Kingdom
| | - Benedikt Klesser
- Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, United Kingdom
| | - Anna Rautanen
- Wellcome Trust Centre for Human Genetics, University of Oxford, Headington, Oxford OX3 7BN, United Kingdom
| | - Martin Frank
- Core Facility Molecular Structure Analysis, German Cancer Research Center, 69120 Heidelberg, Germany
| | - Adrian V S Hill
- Wellcome Trust Centre for Human Genetics, University of Oxford, Headington, Oxford OX3 7BN, United Kingdom
| | - Bénédicte Manoury
- Institut National de la Santé et de la Recherché Médicale, Unité 1151, 75015 Paris, France; Université Paris Descartes, Sorbonne Paris Cité, Faculté de Médecine Paris Descartes, 75015 Paris, France; and
| | - Bruce Beutler
- Center for Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Dominik Hartl
- Department of Pediatrics I, University of Tübingen, 72076 Tübingen, Germany
| | - Alison Simmons
- Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, United Kingdom;
| | - Alexander N R Weber
- Junior Research Group Toll-Like Receptors and Cancer, German Cancer Research Center, 69120 Heidelberg, Germany; Department of Immunology, Interfaculty Institute for Cell Biology, University of Tübingen, 72076 Tübingen, Germany
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110
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Kassiotis G. Endogenous retroviruses and the development of cancer. THE JOURNAL OF IMMUNOLOGY 2014; 192:1343-9. [PMID: 24511094 DOI: 10.4049/jimmunol.1302972] [Citation(s) in RCA: 127] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Mammalian genomes include a considerable number of endogenous retroviruses (ERVs), relics of ancestral infectious retroviruses, whose proviruses have invaded the germ-line. The documented ability of infectious retroviruses to cause cancer has greatly contributed to the discovery of ERVs. It also reinforced the concept that ERVs are causative agents of many cancers, a notion that historically has not always stood up to experimental scrutiny. The recent greater appreciation of the complexity of ERV biology and the identification of dedicated host mechanisms controlling ERV activity have revealed novel interactions between ERVs and their hosts, with the potential to cause or contribute to disease. In this review, the involvement of ERVs in cancer initiation and progression is discussed, as well as their contribution to our understanding of the process of transformation and to the invention of innovative preventive and therapeutic cancer treatments.
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Affiliation(s)
- George Kassiotis
- Division of Immunoregulation, Medical Research Council National Institute for Medical Research, London NW7 1AA, United Kingdom
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111
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Dysfunction of bovine endogenous retrovirus K2 envelope glycoprotein is related to unsuccessful intracellular trafficking. J Virol 2014; 88:6896-905. [PMID: 24696495 DOI: 10.1128/jvi.00288-14] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
UNLABELLED Endogenous retroviruses (ERVs) are the remnants of retroviral infection of ancestral germ cells. Mutations introduced into ERVs halt the production of infectious agents, but their effects on the function of retroviral proteins are not fully understood. Retroviral envelope glycoproteins (Envs) are utilized in membrane fusion during viral entry, and we recently identified intact coding sequences for bovine endogenous retrovirus K1 (BERV-K1) and BERV-K2 Envs. Amino acid sequences of BERV-K1 Env (also called Fematrin-1) and BERV-K2 Env are similar, and both viruses are classified in the genus Betaretrovirus. While Fematrin-1 plays an important role in cell-to-cell fusion in bovine placenta, the BERV-K2 envelope gene is marginally expressed in vivo, and its recombinant Env protein is defective in membrane fusion due to inefficient cleavage of surface (SU) and transmembrane subunits. Here, we conducted chimeric analyses of Fematrin-1 and BERV-K2 Envs and revealed that defective maturation of BERV-K2 Env contributed to failed intracellular trafficking. Fluorescence microscopy and flow cytometric analysis suggested that in contrast to Fematrin-1 Env, BERV-K2 Env could not be transported from the endoplasmic reticulum to the trans-Golgi network, where cellular proteases required for processing retroviral Envs are localized. We also identified that one of the responsive regions of this phenomenon resided within a 65-amino-acid region of BERV-K2 SU. This is the first report to identify that retroviral Env SU is involved in the regulation of intracellular trafficking, and it may help to elucidate the maturation process of Fematrin-1 and other related Envs. IMPORTANCE Retroviruses utilize envelope glycoproteins (Envs) to enter host target cells. Mature retroviral Env is a heterodimer, which consists of surface (SU) and transmembrane (TM) subunits that are generated by the cleavage of an Env precursor protein in the trans-Golgi network. SU and TM mediate the recognition of the entry receptor and virus-host membrane fusion, respectively. However, unexplained issues remain for the maturation process of retroviral Env. We previously reported that bovine endogenous retrovirus K2 (BERV-K2) Env lost fusogenicity due to a defect in the cleavage of SU and TM. In this study, we identified that mutations residing in BERV-K2 SU disturbed intracellular trafficking of BERV-K2 Env and resulted its inefficient cleavage. Because SU is not known to play an important role in this process, our study may provide novel insights into the maturation mechanism of retroviral Envs.
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112
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Probst HC, Muth S, Schild H. Regulation of the tolerogenic function of steady-state DCs. Eur J Immunol 2014; 44:927-33. [PMID: 24652744 DOI: 10.1002/eji.201343862] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2013] [Revised: 12/13/2013] [Accepted: 02/11/2014] [Indexed: 12/18/2022]
Abstract
Dendritic cells (DCs) are master regulators of T-cell responses. After sensing pathogen-derived molecular patterns (PAMPs), or signals of inflammation and cellular stress, DCs differentiate into potent activators of naïve CD4(+) and CD8(+) T cells through a process that is termed DC maturation. By contrast, DCs induce and maintain peripheral T-cell tolerance in the steady state, that is in the absence of overt infection or inflammation. However, the immunological steady state is not devoid of DC-activating stimuli, such as commensal microorganisms, subclinical infections, or basal levels of proinflammatory mediators. In the presence of these activating stimuli, DC maturation must be calibrated to ensure self-tolerance yet allow for adequate T-cell responses to infections. Here, we review the factors that are known to control DC maturation in the steady state and discuss their effect on the tolerogenic function of steady-state DCs.
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Affiliation(s)
- Hans Christian Probst
- Institute for Immunology, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany; Research Center for Immunology (FZI), Johannes Gutenberg University Mainz, Mainz, Germany
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113
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Yoshikawa R, Shimode S, Sakaguchi S, Miyazawa T. Contamination of live attenuated vaccines with an infectious feline endogenous retrovirus (RD-114 virus). Arch Virol 2014; 159:399-404. [PMID: 24068581 PMCID: PMC7086779 DOI: 10.1007/s00705-013-1809-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2013] [Accepted: 06/25/2013] [Indexed: 11/30/2022]
Abstract
Retroviruses are classified as exogenous and endogenous retroviruses according to the mode of transmission. Endogenous retroviruses (ERVs) are retroviruses which have been integrated into germ-line cells and inherited from parents to offspring. Most ERVs are inactivated by deletions and mutations; however, certain ERVs maintain their infectivity and infect the same host and new hosts as exogenous retroviruses. All domestic cats have infectious ERVs, termed RD-114 virus. Several canine and feline attenuated vaccines are manufactured using RD-114 virus-producing cell lines such as Crandell-Rees feline kidney cells; therefore, it is possible that infectious RD-114 virus contaminates live attenuated vaccines. Recently, Japanese and UK research groups found that several feline and canine vaccines were indeed contaminated with infectious RD-114 virus. This was the first incidence of contamination of 'infectious' ERVs in live attenuated vaccines. RD-114 virus replicates efficiently in canine cell lines and primary cells. Therefore, it is possible that RD-114 virus infects dogs following inoculation with contaminated vaccines and induces proliferative diseases and immune suppression, if it adapts to grow efficiently in dogs. In this review, we summarize the incidence of contamination of RD-114 virus in live attenuated vaccines and potential risks of infection with RD-114 virus in dogs.
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Affiliation(s)
- Rokusuke Yoshikawa
- Laboratory of Signal Transduction, Department of Cell Biology, Institute for Virus Research, Kyoto University, 53 Shogoin-Kawaharacho, Sakyo-ku, Kyoto, 606-8507 Japan
- Graduate School of Human and Environmental Studies, Kyoto University, Yoshida-Nihonmatsucho, Sakyo-ku, Kyoto, 606-8501 Japan
- Research Fellow of the Japan Society for the Promotion of Science, 5-3-1 Koujimachi, Chiyoda-ku, Tokyo, 102-0083 Japan
| | - Sayumi Shimode
- Laboratory of Signal Transduction, Department of Cell Biology, Institute for Virus Research, Kyoto University, 53 Shogoin-Kawaharacho, Sakyo-ku, Kyoto, 606-8507 Japan
| | - Shoichi Sakaguchi
- Laboratory of Signal Transduction, Department of Cell Biology, Institute for Virus Research, Kyoto University, 53 Shogoin-Kawaharacho, Sakyo-ku, Kyoto, 606-8507 Japan
- Research Fellow of the Japan Society for the Promotion of Science, 5-3-1 Koujimachi, Chiyoda-ku, Tokyo, 102-0083 Japan
| | - Takayuki Miyazawa
- Laboratory of Signal Transduction, Department of Cell Biology, Institute for Virus Research, Kyoto University, 53 Shogoin-Kawaharacho, Sakyo-ku, Kyoto, 606-8507 Japan
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114
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Evans LH, Boi S, Malik F, Wehrly K, Peterson KE, Chesebro B. Analysis of two monoclonal antibodies reactive with envelope proteins of murine retroviruses: one pan specific antibody and one specific for Moloney leukemia virus. J Virol Methods 2014; 200:47-53. [PMID: 24556162 DOI: 10.1016/j.jviromet.2014.02.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Revised: 01/25/2014] [Accepted: 02/04/2014] [Indexed: 01/08/2023]
Abstract
Many monoclonal antibodies (MAbs) reactive with various proteins of murine leukemia viruses (MuLVs) have been developed. In this report two additional MAbs with differing and unusual specificities are described. MAb 573 is reactive with the envelope protein of all MuLVs tested including viruses in the ecotropic, xenotropic, polytropic and amphotropic classes. Notably, MAb 573 is one of only two reported MAbs that react with the envelope protein of amphotropic MuLVs. This MAb appears to recognize a conformational epitope within the envelope protein, as it reacts strongly with live virus and live infected cells, but does not react with formalin-fixed or alcohol-fixed infected cells or denatured viral envelope protein in immunoblots. In contrast, Mab 538 reacts only with an epitope unique to the envelope protein of the Moloney (Mo-) strain of MuLV, a prototypic ecotropic MuLV that is the basis for many retroviral tools used in molecular biology. MAb 538 can react with live cells and viruses, or detergent denatured or fixed envelope protein. The derivation of these antibodies as well as their characterization with regard to their isotype, range of reactivity with different MuLVs and utility in different immunological procedures are described in this study.
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Affiliation(s)
- Leonard H Evans
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, Hamilton, MT 59840, United States.
| | - Stefano Boi
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, Hamilton, MT 59840, United States; Department of Biomedical Sciences, University of Cagliari, 09042 Monserrato (CA), Italy
| | - Frank Malik
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, Hamilton, MT 59840, United States
| | - Kathy Wehrly
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, Hamilton, MT 59840, United States
| | - Karin E Peterson
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, Hamilton, MT 59840, United States
| | - Bruce Chesebro
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, Hamilton, MT 59840, United States
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115
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Rigby RE, Webb LM, Mackenzie KJ, Li Y, Leitch A, Reijns MAM, Lundie RJ, Revuelta A, Davidson DJ, Diebold S, Modis Y, MacDonald AS, Jackson AP. RNA:DNA hybrids are a novel molecular pattern sensed by TLR9. EMBO J 2014; 33:542-58. [PMID: 24514026 PMCID: PMC3989650 DOI: 10.1002/embj.201386117] [Citation(s) in RCA: 125] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
The sensing of nucleic acids by receptors of the innate immune system is a key component of antimicrobial immunity. RNA:DNA hybrids, as essential intracellular replication intermediates generated during infection, could therefore represent a class of previously uncharacterised pathogen-associated molecular patterns sensed by pattern recognition receptors. Here we establish that RNA:DNA hybrids containing viral-derived sequences efficiently induce pro-inflammatory cytokine and antiviral type I interferon production in dendritic cells. We demonstrate that MyD88-dependent signalling is essential for this cytokine response and identify TLR9 as a specific sensor of RNA:DNA hybrids. Hybrids therefore represent a novel molecular pattern sensed by the innate immune system and so could play an important role in host response to viruses and the pathogenesis of autoimmune disease.
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Affiliation(s)
- Rachel E Rigby
- MRC Human Genetics Unit, MRC IGMM, University of EdinburghEdinburgh, UK
- MRC Human Immunology Unit, Radcliffe Department of Medicine, MRC WIMM, University of OxfordOxford, UK
| | - Lauren M Webb
- Institute of Immunology and Infection Research, University of EdinburghEdinburgh, UK
- Manchester Collaborative Centre for Inflammation Research, University of ManchesterManchester, UK
| | - Karen J Mackenzie
- MRC Human Genetics Unit, MRC IGMM, University of EdinburghEdinburgh, UK
| | - Yue Li
- Department of Molecular Biophysics and Biochemistry, Yale UniversityNew Haven, CT, USA
| | - Andrea Leitch
- MRC Human Genetics Unit, MRC IGMM, University of EdinburghEdinburgh, UK
| | - Martin A M Reijns
- MRC Human Genetics Unit, MRC IGMM, University of EdinburghEdinburgh, UK
| | - Rachel J Lundie
- Institute of Immunology and Infection Research, University of EdinburghEdinburgh, UK
| | - Ailsa Revuelta
- MRC Human Genetics Unit, MRC IGMM, University of EdinburghEdinburgh, UK
| | - Donald J Davidson
- MRC Centre for Inflammation Research, Queen's Medical Research Institute, The University of EdinburghEdinburgh, UK
| | - Sandra Diebold
- Division of Immunology, Infection and Inflammatory Disease, King's College LondonLondon, UK
| | - Yorgo Modis
- Department of Molecular Biophysics and Biochemistry, Yale UniversityNew Haven, CT, USA
| | - Andrew S MacDonald
- Institute of Immunology and Infection Research, University of EdinburghEdinburgh, UK
- Manchester Collaborative Centre for Inflammation Research, University of ManchesterManchester, UK
- *Corresponding author. Tel: +44 161 275 1504; E-mail:
| | - Andrew P Jackson
- MRC Human Genetics Unit, MRC IGMM, University of EdinburghEdinburgh, UK
- **Corresponding author. Tel: +44 131 332 2471; Fax: +44 131 467 8456;
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116
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Lee-Kirsch MA, Wolf C, Günther C. Aicardi-Goutières syndrome: a model disease for systemic autoimmunity. Clin Exp Immunol 2014; 175:17-24. [PMID: 23786362 DOI: 10.1111/cei.12160] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/15/2013] [Indexed: 02/06/2023] Open
Abstract
Systemic autoimmunity is a complex disease process that results from a loss of immunological tolerance characterized by the inability of the immune system to discriminate self from non-self. In patients with the prototypic autoimmune disease systemic lupus erythematosus (SLE), formation of autoantibodies targeting ubiquitous nuclear antigens and subsequent deposition of immune complexes in the vascular bed induces inflammatory tissue injury that can affect virtually any organ system. Given the extraordinary genetic and phenotypic heterogeneity of SLE, one approach to the genetic dissection of complex SLE is to study monogenic diseases, for which a single gene defect is responsible. Considerable success has been achieved from the analysis of the rare monogenic disorder Aicardi-Goutières syndrome (AGS), an inflammatory encephalopathy that clinically resembles in-utero-acquired viral infection and that also shares features with SLE. Progress in understanding the cellular and molecular functions of the AGS causing genes has revealed novel pathways of the metabolism of intracellular nucleic acids, the major targets of the autoimmune attack in patients with SLE. Induction of autoimmunity initiated by immune recognition of endogenous nucleic acids originating from processes such as DNA replication/repair or endogenous retro-elements represents novel paradigms of SLE pathogenesis. These findings illustrate how investigating rare monogenic diseases can also fuel discoveries that advance our understanding of complex disease. This will not only aid the development of improved tools for SLE diagnosis and disease classification, but also the development of novel targeted therapeutic approaches.
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Affiliation(s)
- M A Lee-Kirsch
- Department of Pediatrics, University Hospital, Technical University Dresden, Dresden, Germany
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117
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Sriram U, Xu J, Chain RW, Varghese L, Chakhtoura M, Bennett HL, Zoltick PW, Gallucci S. IL-4 suppresses the responses to TLR7 and TLR9 stimulation and increases the permissiveness to retroviral infection of murine conventional dendritic cells. PLoS One 2014; 9:e87668. [PMID: 24489947 PMCID: PMC3906189 DOI: 10.1371/journal.pone.0087668] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Accepted: 12/28/2013] [Indexed: 12/11/2022] Open
Abstract
Th2-inducing pathological conditions such as parasitic diseases increase susceptibility to viral infections through yet unclear mechanisms. We have previously reported that IL-4, a pivotal Th2 cytokine, suppresses the response of murine bone-marrow-derived conventional dendritic cells (cDCs) and splenic DCs to Type I interferons (IFNs). Here, we analyzed cDC responses to TLR7 and TLR9 ligands, R848 and CpGs, respectively. We found that IL-4 suppressed the gene expression of IFNβ and IFN-responsive genes (IRGs) upon TLR7 and TLR9 stimulation. IL-4 also inhibited IFN-dependent MHC Class I expression and amplification of IFN signaling pathways triggered upon TLR stimulation, as indicated by the suppression of IRF7 and STAT2. Moreover, IL-4 suppressed TLR7- and TLR9-induced cDC production of pro-inflammatory cytokines such as TNFα, IL-12p70 and IL-6 by inhibiting IFN-dependent and NFκB-dependent responses. IL-4 similarly suppressed TLR responses in splenic DCs. IL-4 inhibition of IRGs and pro-inflammatory cytokine production upon TLR7 and TLR9 stimulation was STAT6-dependent, since DCs from STAT6-KO mice were resistant to the IL-4 suppression. Analysis of SOCS molecules (SOCS1, −2 and −3) showed that IL-4 induces SOCS1 and SOCS2 in a STAT6 dependent manner and suggest that IL-4 suppression could be mediated by SOCS molecules, in particular SOCS2. IL-4 also decreased the IFN response and increased permissiveness to viral infection of cDCs exposed to a HIV-based lentivirus. Our results indicate that IL-4 modulates and counteracts pro-inflammatory stimulation induced by TLR7 and TLR9 and it may negatively affect responses against viruses and intracellular parasites.
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Affiliation(s)
- Uma Sriram
- Laboratory of Dendritic Cell Biology, Department of Microbiology and Immunology, Temple University, School of Medicine, Philadelphia, Pennsylvania, United States of America
- * E-mail: (US); (SG)
| | - Jun Xu
- Laboratory of Dendritic Cell Biology, Department of Microbiology and Immunology, Temple University, School of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Robert W. Chain
- Laboratory of Dendritic Cell Biology, Department of Microbiology and Immunology, Temple University, School of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Linda Varghese
- Laboratory of Dendritic Cell Biology, Department of Microbiology and Immunology, Temple University, School of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Marita Chakhtoura
- Laboratory of Dendritic Cell Biology, Department of Microbiology and Immunology, Temple University, School of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Heather L. Bennett
- Joseph Stokes, Jr. Research Institute, Division of Rheumatology, Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, United States of America
| | - Philip W. Zoltick
- Department of Surgery, The Children's Center for Fetal Research, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, United States of America
| | - Stefania Gallucci
- Laboratory of Dendritic Cell Biology, Department of Microbiology and Immunology, Temple University, School of Medicine, Philadelphia, Pennsylvania, United States of America
- * E-mail: (US); (SG)
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118
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Matsumoto M, Funami K, Tatematsu M, Azuma M, Seya T. Assessment of the Toll-like receptor 3 pathway in endosomal signaling. Methods Enzymol 2014; 535:149-65. [PMID: 24377923 DOI: 10.1016/b978-0-12-397925-4.00010-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The innate immune system plays key roles in antimicrobial responses by developing the pattern-recognition receptors that recognize microbial components. The endosomal Toll-like receptors (TLRs) and cytosolic RIG-I-like receptors (RLRs) both recognize viral nucleic acids and are essential for antiviral immunity. Recent evidence suggests that compartmentalization of the receptors, and also their adaptor molecule, is important for discrimination between self and nonself and for distinct innate immune signals. TLR3 is a type I transmembrane protein that localizes in the endosomal membrane in myeloid dendritic cells (DCs) and fibroblasts/epithelial cells. TLR3 recognizes extracellular viral double-stranded RNA (dsRNA) and the synthetic dsRNA, poly(I:C). On recognition of dsRNA in the endosomes, TLR3 oligomerizes and induces type I interferon and proinflammatory cytokine production via an adaptor molecule, TICAM-1 (also known as TRIF). Additionally, the TLR3 signal in DCs triggers gene transcription required for DC maturation and the activation of natural killer cells and cytotoxic T lymphocytes. Remarkably, it has been reported that extracellular dsRNA is also recognized by cytosolic RLR. Making a distinction between TLR3-mediated endosomal signaling and RLR-mediated signaling is key to understanding the role of these receptors in innate immunity.
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Affiliation(s)
- Misako Matsumoto
- Department of Microbiology and Immunology, Hokkaido University Graduate School of Medicine, Kita-ku, Sapporo, Japan.
| | - Kenji Funami
- Department of Microbiology and Immunology, Hokkaido University Graduate School of Medicine, Kita-ku, Sapporo, Japan
| | - Megumi Tatematsu
- Department of Microbiology and Immunology, Hokkaido University Graduate School of Medicine, Kita-ku, Sapporo, Japan
| | - Masahiro Azuma
- Department of Microbiology and Immunology, Hokkaido University Graduate School of Medicine, Kita-ku, Sapporo, Japan
| | - Tsukasa Seya
- Department of Microbiology and Immunology, Hokkaido University Graduate School of Medicine, Kita-ku, Sapporo, Japan
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119
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Use of IRF-3 and/or IRF-7 knockout mice to study viral pathogenesis: lessons from a murine retrovirus-induced AIDS model. J Virol 2013; 88:2349-53. [PMID: 24335302 DOI: 10.1128/jvi.02960-13] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Interferon regulatory factor (IRF) regulation of the type I interferon response has not been extensively explored in murine retroviral infections. IRF-3(-/-) and select IRF-3/7(-/-) mice were resistant to LP-BM5-induced pathogenesis. However, further analyses strongly suggested that resistance could be attributed to strain 129-specific contamination of the known retrovirus resistance gene Fv1. Therefore, caution should be taken when interpreting phenotypes observed in these knockout mice, as strain 129-derived genetic polymorphisms may explain observed differences.
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120
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Dewannieux M, Heidmann T. Endogenous retroviruses: acquisition, amplification and taming of genome invaders. Curr Opin Virol 2013; 3:646-56. [DOI: 10.1016/j.coviro.2013.08.005] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2013] [Revised: 08/13/2013] [Accepted: 08/14/2013] [Indexed: 12/12/2022]
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121
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Jinushi M. Yin and yang of tumor inflammation: how innate immune suppressors shape the tumor microenvironments. Int J Cancer 2013; 135:1277-85. [PMID: 24272248 DOI: 10.1002/ijc.28626] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2013] [Accepted: 11/19/2013] [Indexed: 01/12/2023]
Abstract
Pattern recognition-mediated sensing systems direct host immunity towards either antitumor immunosurveillance or protumorigenic inflammation. These activities imply dual and conflicting roles in the regulation of tumor-associated inflammation. On the one hand, recent evidence has revealed that several signaling components and cell-surface receptors suppress innate immune signals and constitute a negative feedback machinery preventing excess and continuous inflammation within tumor microenvironments. On the other hand, these same components also negatively regulate intrinsic tumorigenic activities by targeting nuclear factor-kappaB (NF-κB)-mediated antiapoptotic and inflammatory signals. Furthermore, the activation status of innate immune suppressors may reflect the functional plasticity of interactions between tumor cells and innate immune cells and determine whether tumor inflammation supports anti- or pro-tumorigenic responses. Thus, innate immune suppressors may provide valuable information about the immunogenic or tumorigenic status of tumor-associated inflammation thereby serving as potential biomarkers that predict tumor progression. Comprehensive analysis for identifying general and unique features of each innate immune suppressor in the regulation of tumor inflammation should explore the development of new biomarkers for improving future therapeutic strategies.
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Affiliation(s)
- Masahisa Jinushi
- Institute for Genetic Medicine, Hokkaido University, Sapporo, 060-0815, Japan
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122
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Magor KE, Miranzo Navarro D, Barber MRW, Petkau K, Fleming-Canepa X, Blyth GAD, Blaine AH. Defense genes missing from the flight division. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2013; 41:377-88. [PMID: 23624185 PMCID: PMC7172724 DOI: 10.1016/j.dci.2013.04.010] [Citation(s) in RCA: 117] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2013] [Accepted: 04/16/2013] [Indexed: 05/12/2023]
Abstract
Birds have a smaller repertoire of immune genes than mammals. In our efforts to study antiviral responses to influenza in avian hosts, we have noted key genes that appear to be missing. As a result, we speculate that birds have impaired detection of viruses and intracellular pathogens. Birds are missing TLR8, a detector for single-stranded RNA. Chickens also lack RIG-I, the intracellular detector for single-stranded viral RNA. Riplet, an activator for RIG-I, is also missing in chickens. IRF3, the nuclear activator of interferon-beta in the RIG-I pathway is missing in birds. Downstream of interferon (IFN) signaling, some of the antiviral effectors are missing, including ISG15, and ISG54 and ISG56 (IFITs). Birds have only three antibody isotypes and IgD is missing. Ducks, but not chickens, make an unusual truncated IgY antibody that is missing the Fc fragment. Chickens have an expanded family of LILR leukocyte receptor genes, called CHIR genes, with hundreds of members, including several that encode IgY Fc receptors. Intriguingly, LILR homologues appear to be missing in ducks, including these IgY Fc receptors. The truncated IgY in ducks, and the duplicated IgY receptor genes in chickens may both have resulted from selective pressure by a pathogen on IgY FcR interactions. Birds have a minimal MHC, and the TAP transport and presentation of peptides on MHC class I is constrained, limiting function. Perhaps removing some constraint, ducks appear to lack tapasin, a chaperone involved in loading peptides on MHC class I. Finally, the absence of lymphotoxin-alpha and beta may account for the observed lack of lymph nodes in birds. As illustrated by these examples, the picture that emerges is some impairment of immune response to viruses in birds, either a cause or consequence of the host-pathogen arms race and long evolutionary relationship of birds and RNA viruses.
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Affiliation(s)
- Katharine E Magor
- Department of Biological Sciences, University of Alberta, Edmonton, Canada.
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123
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Zhang J, Crumpacker C. Eradication of HIV and Cure of AIDS, Now and How? Front Immunol 2013; 4:337. [PMID: 24151495 PMCID: PMC3799464 DOI: 10.3389/fimmu.2013.00337] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2013] [Accepted: 10/03/2013] [Indexed: 11/13/2022] Open
Abstract
Recent studies have highlighted the importance of eradication of human immunodeficiency virus (HIV) and cure of acquired immunodeficiency syndrome (AIDS). However, a pivotal point that the patient immunity controls HIV reactivation after highly active anti-retroviral therapy [HAART or combination anti-retroviral therapy (cART)] remains less well addressed. In spite of the fact that both innate and adaptive immunities are indispensable and numerous cells participate in the anti-HIV immunity, memory CD4 T-cells are indisputably the key cells organizing all immune actions against HIV while being the targets of HIV. Here we present a view and multidisciplinary approaches to HIV/AIDS eradication and cure. We aim at memory CD4 T-cells, utilizing the stem cell properties of these cells to reprogram an anti-HIV memory repertoire to eliminate the viral reservoir, toward achieving an AIDS-free world.
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Affiliation(s)
- Jielin Zhang
- Department of Medicine, Beth Israel Deaconess Medical Center , Boston, MA , USA
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124
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Differential requirements of cellular and humoral immune responses for Fv2-associated resistance to erythroleukemia and for regulation of retrovirus-induced myeloid leukemia development. J Virol 2013; 87:13760-74. [PMID: 24109240 DOI: 10.1128/jvi.02506-13] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
To assess the possible contribution of host immune responses to the exertion of Fv2-associated resistance to Friend virus (FV)-induced disease development, we inoculated C57BL/6 (B6) mice that lacked various subsets of lymphocytes with FV containing no lactate dehydrogenase-elevating virus. Fv2(r) B6 mice lacking CD4(+) T cells developed early polycythemia and fatal erythroleukemia, while B6 mice lacking CD8(+) T cells remained resistant. Erythroid progenitor cells infected with spleen focus-forming virus (SFFV) were eliminated, and no polycythemia was observed in B cell-deficient B6 mice, but they later developed myeloid leukemia associated with oligoclonal integration of ecotropic Friend murine leukemia virus. Additional depletion of natural killer and/or CD8(+) T cells from B cell-deficient B6 mice resulted in the expansion of SFFV proviruses and the development of polycythemia, indicating that SFFV-infected erythroid cells are not only restricted in their growth but are actively eliminated in Fv2(r) mice through cellular immune responses.
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125
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TLR3- and MyD88-dependent signaling differentially influences the development of West Nile virus-specific B cell responses in mice following immunization with RepliVAX WN, a single-cycle flavivirus vaccine candidate. J Virol 2013; 87:12090-101. [PMID: 23986602 DOI: 10.1128/jvi.01469-13] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Recognition of conserved pathogen-associated molecular patterns (PAMPs) by host pattern recognition receptors (PRRs) results in the activation of innate signaling pathways that drive the innate immune response and ultimately shape the adaptive immune response. RepliVAX WN, a single-cycle flavivirus (SCFV) vaccine candidate derived from West Nile virus (WNV), is intrinsically adjuvanted with multiple PAMPs and induces a vigorous anti-WNV humoral response. However, the innate mechanisms that link pattern recognition and development of vigorous antigen-specific B cell responses are not completely understood. Moreover, the roles of individual PRR signaling pathways in shaping the B cell response to this live attenuated SCFV vaccine have not been established. We examined and compared the role of TLR3- and MyD88-dependent signaling in the development of anti-WNV-specific antibody-secreting cell responses and memory B cell responses induced by RepliVAX WN. We found that MyD88 deficiency significantly diminished B cell responses by impairing B cell activation, development of germinal centers (GC), and the generation of long-lived plasma cells (LLPCs) and memory B cells (MBCs). In contrast, TLR3 deficiency had more effect on maintenance of GCs and development of LLPCs, whereas differentiation of MBCs was unaffected. Our data suggest that both TLR3- and MyD88-dependent signaling are involved in the intrinsic adjuvanting of RepliVAX WN and differentially contribute to the development of vigorous WNV-specific antibody and B cell memory responses following immunization with this novel SCFV vaccine.
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126
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The Yin and Yang of Toll-like receptors in cancer. Oncogene 2013; 33:3485-95. [PMID: 23934186 DOI: 10.1038/onc.2013.302] [Citation(s) in RCA: 227] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2013] [Accepted: 06/10/2013] [Indexed: 02/08/2023]
Abstract
Recognition of non-self molecular patterns by pattern recognition receptors is a cornerstone of innate immunity. Toll-like receptors (TLRs) exert a key role in recognizing pathogen-associated molecular patterns (PAMPs) but have also been implicated in the recognition of damage-associated molecular patterns (DAMPs). As such, TLRs regulate a wide range of biological responses including inflammatory and immune responses during carcinogenesis. The high expression of TLRs by antigen-presenting cells, including dendritic cells, and their ability to induce antitumor mediators such as type I interferon has led to efforts to utilize TLR agonists in tumor therapy in order to convert the often tolerant immune response toward antitumor responses. However, TLRs are also increasingly recognized as regulators of tumor-promoting inflammation and promoters of tumor survival signals. Here, we will review in detail the dichotomous role of TLRs in tumor biology, focusing on relevant TLR-dependent pro- and antitumor pathways, and discuss clinical applications of TLR-targeted therapies for tumor prevention and treatment.
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127
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Cen P, Ye L, Su QJ, Wang X, Li JL, Lin XQ, Liang H, Ho WZ. Methamphetamine inhibits Toll-like receptor 9-mediated anti-HIV activity in macrophages. AIDS Res Hum Retroviruses 2013; 29:1129-37. [PMID: 23751096 DOI: 10.1089/aid.2012.0264] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Toll-like receptor 9 (TLR9) is one of the key sensors that recognize viral infection/replication in the host cells. Studies have demonstrated that methamphetamine (METH) dysregulated host cell innate immunity and facilitated HIV infection of macrophages. In this study, we present new evidence that METH suppressed TLR9-mediated anti-HIV activity in macrophages. Activation of TLR9 by its agonist CpG-ODN 2216 inhibits HIV replication, which was demonstrated by increased expression of TLR9, interferon (IFN)-α, IFN regulatory factor-7 (IRF-7), myeloid differentiation factor 88 (MyD88), and myxovirus resistance gene A (MxA) in macrophages. However, METH treatment of macrophages greatly compromised the TLR9 signaling-mediated anti-HIV effect and inhibited the expression of TLR9 downstream signaling factors. Dopamine D1 receptor (D1R) antagonists (SCH23390) could block METH-mediated inhibition of anti-HIV activity of TLR9 signaling. Investigation of the underlying mechanisms of the METH action showed that METH treatment selectively down-regulated the expression of TLR9 on macrophages, whereas it had little effect on the expression of other TLRs. Collectively, our results provide further evidence that METH suppresses host cell innate immunity against HIV infection by down-regulating TLR9 expression and its signaling-mediated antiviral effect in macrophages.
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Affiliation(s)
- Ping Cen
- Department of Pathology and Laboratory Medicine, Temple University School of Medicine, Philadelphia, Pennsylvania
- Nanning Center for Disease Control and Prevention, Nanning, Guangxi, People's Republic of China
| | - Li Ye
- Guangxi Key Laboratory of AIDS Prevention and Treatment, School of Public Health, Guangxi Medical University, Nanning, People's Republic of China
| | - Qi-Jian Su
- Center for AIDS Research, the Affiliated Ruikang Hospital of Guangxi University of Chinese Medicine, Nanning, People's Republic of China
| | - Xu Wang
- Department of Pathology and Laboratory Medicine, Temple University School of Medicine, Philadelphia, Pennsylvania
| | - Jie-Liang Li
- Department of Pathology and Laboratory Medicine, Temple University School of Medicine, Philadelphia, Pennsylvania
| | - Xin-Qin Lin
- Nanning Center for Disease Control and Prevention, Nanning, Guangxi, People's Republic of China
| | - Hao Liang
- Guangxi Key Laboratory of AIDS Prevention and Treatment, School of Public Health, Guangxi Medical University, Nanning, People's Republic of China
| | - Wen-Zhe Ho
- Department of Pathology and Laboratory Medicine, Temple University School of Medicine, Philadelphia, Pennsylvania
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128
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Salcedo R, Cataisson C, Hasan U, Yuspa SH, Trinchieri G. MyD88 and its divergent toll in carcinogenesis. Trends Immunol 2013; 34:379-89. [PMID: 23660392 PMCID: PMC3847901 DOI: 10.1016/j.it.2013.03.008] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2013] [Revised: 03/21/2013] [Accepted: 03/31/2013] [Indexed: 02/07/2023]
Abstract
Toll-like and interleukin-1 (IL-1) family receptors recognize microbial or endogenous ligands and inflammatory mediators, respectively, and with the exception of Toll-like receptor 3 (TLR3), signal via the adaptor molecule myeloid differentiation factor 88 (MyD88). MyD88 is involved in oncogene-induced cell intrinsic inflammation and in cancer-associated extrinsic inflammation, and as such MyD88 contributes to skin, liver, pancreatic, and colon carcinogenesis, as well as sarcomagenesis. MyD88 is also protective, for example in oncogenic virus carcinogenesis or, acting downstream of IL-18R to strengthen mucosal repair, in azoxymethane (AOM)/dextran sulfate sodium (DSS)-induced colon carcinogenesis. Here, we discuss the mechanisms of the divergent effects of MyD88 and the balance of its protumor role in cancer-enhancing inflammation and immunity and its antitumor role in tissue homeostasis, repair, and immunity against the tumor or oncogenic pathogens.
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Affiliation(s)
- Rosalba Salcedo
- Cancer and Inflammation Program, National Cancer Institute, Frederick, MD 217023, USA
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129
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Abstract
We compared the plasma viromes of HIV-infected subjects with low versus high CD4(+) T cell counts from the United States and Uganda by using deep sequencing and detected HIV, hepatitis C virus, hepatitis B virus, GB virus C, anellovirus, and human endogenous retrovirus (HERV) reads. An increase in the proportion of reads for anelloviruses, a family of highly prevalent and genetically diverse human viruses, was seen in subjects with AIDS from both countries. The proportion of endogenous human retrovirus reads was increased in AIDS subjects from Uganda but not the United States. Progression to AIDS is therefore associated with changes in the plasma concentration of commensal viruses.
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130
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Young GR, Stoye JP, Kassiotis G. Are human endogenous retroviruses pathogenic? An approach to testing the hypothesis. Bioessays 2013; 35:794-803. [PMID: 23864388 PMCID: PMC4352332 DOI: 10.1002/bies.201300049] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
A number of observations have led researchers to postulate that, despite being replication-defective, human endogenous retroviruses (HERVs) may have retained the potential to cause or contribute to disease. However, mechanisms of HERV pathogenicity might differ substantially from those of modern infectious retroviruses or of the infectious precursors of HERVs. Therefore, novel pathways of HERV involvement in disease pathogenesis should be investigated. Recent technological advances in sequencing and bioinformatics are making this task increasingly feasible. The accumulating knowledge of HERV biology may also facilitate the definition and general acceptance of criteria that establish HERV pathogenicity. Here, we explore possible mechanisms whereby HERVs may cause disease and examine the evidence that either has been or should be obtained in order to decisively address the pathogenic potential of HERVs.
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Affiliation(s)
- George R Young
- Division of Virology, MRC National Institute for Medical Research, London, UK
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131
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Zinc-finger antiviral protein mediates retinoic acid inducible gene I-like receptor-independent antiviral response to murine leukemia virus. Proc Natl Acad Sci U S A 2013; 110:12379-84. [PMID: 23836649 DOI: 10.1073/pnas.1310604110] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
When host cells are infected by an RNA virus, pattern-recognition receptors (PRRs) recognize the viral RNA and induce the antiviral innate immunity. Toll-like receptor 7 (TLR7) detects the genomic RNA of incoming murine leukemia virus (MLV) in endosomes and mediates the antiviral response. However, the RNA-sensing PRR that recognizes the MLV in the cytosol is not fully understood. Here, we definitively demonstrate that zinc-finger antiviral protein (ZAP) acts as a cytosolic RNA sensor, inducing the degradation of the MLV transcripts by the exosome, an RNA degradation system, on RNA granules. Although the retinoic acid inducible gene I (RIG-I)-like receptors (RLRs) RIG-I and melanoma differentiation-associated protein 5 detect various RNA viruses in the cytosol and induce the type I IFN-dependent antiviral response, RLR loss does not alter the replication efficiency of MLV. In sharp contrast, the loss of ZAP greatly enhances the replication efficiency of MLV. ZAP localizes to RNA granules, where the processing-body and stress-granule proteins assemble. ZAP induces the recruitment of the MLV transcripts and exosome components to the RNA granules. The CCCH-type zinc-finger domains of ZAP, which are RNA-binding motifs, mediate its localization to RNA granules and MLV transcripts degradation by the exosome. Although ZAP was known as a regulator of RIG-I signaling in a human cell line, ZAP deficiency does not affect the RIG-I-dependent production of type I IFN in mouse cells. Thus, ZAP is a unique member of the cytosolic RNA-sensing PRR family that targets and eliminates intracellular RNA viruses independently of TLR and RLR family members.
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132
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Mavrommatis B, Young GR, Kassiotis G. Counterpoise between the microbiome, host immune activation and pathology. Curr Opin Immunol 2013; 25:456-62. [PMID: 23743081 DOI: 10.1016/j.coi.2013.05.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2013] [Revised: 05/03/2013] [Accepted: 05/08/2013] [Indexed: 12/13/2022]
Abstract
The role of the mammalian intestinal microbiota in health and disease of the host has long been recognized and extensively studied. Largely, these studies have focused on the bacterial component of the microbiota. However, recent technological advances have shed new light on the microbiome at distinct anatomical locations and uncovered the role of additional microbial symbionts, including the virome and endogenous retroelements. Together, they have revealed interactions more intricate than previously recognized. Here, we review recent advances in our knowledge of this collective microbiome and the interactions with the immune system of their host.
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Affiliation(s)
- Bettina Mavrommatis
- Division of Immunoregulation, MRC National Institute for Medical Research, The Ridgeway, London NW7 1AA, UK
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133
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Gürtler C, Bowie AG. Innate immune detection of microbial nucleic acids. Trends Microbiol 2013; 21:413-20. [PMID: 23726320 DOI: 10.1016/j.tim.2013.04.004] [Citation(s) in RCA: 196] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Revised: 04/05/2013] [Accepted: 04/17/2013] [Indexed: 12/24/2022]
Abstract
Detection of pathogen-derived nucleic acids by pattern recognition receptors (PRRs) is essential for the host to mount an appropriate immune response, which for viruses involves the induction of type I interferons (IFNs). By contrast, inappropriate activation of PRRs by self nucleic acids can lead to autoimmunity. Recent developments in PRR research have uncovered important new molecular details as to how Toll-like receptors (TLRs) and retinoic acid-inducible gene-I (RIG-I)-like receptors (RLRs) distinguish pathogen from self RNA, while the discovery of cytosolic DNA sensing pathways for IFN induction has revealed completely new innate signaling mechanisms, and also questions how innate immunity discriminates between self and non-self DNA, if at all.
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Affiliation(s)
- Claudia Gürtler
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin 2, Ireland
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134
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Shimode S, Nakaoka R, Shogen H, Miyazawa T. Characterization of feline ASCT1 and ASCT2 as RD-114 virus receptor. J Gen Virol 2013; 94:1608-1612. [PMID: 23580426 DOI: 10.1099/vir.0.052928-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
RD-114 virus is a replication-competent feline endogenous retrovirus (ERV). RD-114 virus had been thought to be xenotropic; however, recent findings indicate that RD-114 virus is polytropic and can infect and grow efficiently in feline cells. Receptor(s) for RD-114 virus has not been identified and characterized in cats. In this study, we confirmed that two feline sodium-dependent neutral amino acid transporters (ASCTs), fASCT1 and fASCT2, function as RD-114 virus receptors. By chimeric analyses of feline and murine ASCTs, we revealed that extracellular loop 2 of both fASCT1 and fASCT2 determines the susceptibility to RD-114 virus. Further, we revealed ubiquitous expression of these genes, consistent with the general metabolic role of the ASCT molecules. Our study indicates that RD-114 virus may reinfect tissues and cells in cats, once the virus is activated. Implications of the involvement of RD-114 virus in feline oncogenesis are also discussed.
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Affiliation(s)
- Sayumi Shimode
- Laboratory of Signal Transduction, Department of Cell Biology, Institute for Virus Research, Kyoto University, 53 Shogoin-Kawaharacho, Sakyo-ku, Kyoto 606-8501, Japan
| | - Rie Nakaoka
- Department of Veterinary Pathology, School of Veterinary Medicine, Rakuno Gakuen University, 582 Bunkyodai-Midorimachi, Ebetsu 069-8501, Japan
| | - Hiroko Shogen
- Laboratory of Signal Transduction, Department of Cell Biology, Institute for Virus Research, Kyoto University, 53 Shogoin-Kawaharacho, Sakyo-ku, Kyoto 606-8501, Japan
| | - Takayuki Miyazawa
- Laboratory of Signal Transduction, Department of Cell Biology, Institute for Virus Research, Kyoto University, 53 Shogoin-Kawaharacho, Sakyo-ku, Kyoto 606-8501, Japan
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135
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Chen L, Li Q, Su J, Yang C, Li Y, Rao Y. Trunk kidney of grass carp (Ctenopharyngodon idella) mediates immune responses against GCRV and viral/bacterial PAMPs in vivo and in vitro. FISH & SHELLFISH IMMUNOLOGY 2013; 34:909-919. [PMID: 23333439 DOI: 10.1016/j.fsi.2013.01.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2012] [Revised: 01/02/2013] [Accepted: 01/04/2013] [Indexed: 06/01/2023]
Abstract
Trunk kidney is a vital organ for excretion in teleosts. There have been sporadic reports of processing pathogens for the immune function in trunk kidney. However, molecular processes of pathogen recognition receptors (PRRs) responding to virus and viral/bacterial pathogen-associated molecular patterns (PAMPs) are poorly elucidated in trunk kidney. In the present study, we investigated transcriptional profiles of twelve representative immune-related genes (TLRs (TLR3, TLR7 and TLR22); RLRs (RIG-I, MDA5 and LGP2); NLRs (NOD1 and NOD2); adapter molecules (MyD88 and IPS-1); effector molecule type I interferon (IFN-I) and immunoglobulin M (IgM)) in trunk kidney tissue of grass carp (Ctenopharyngodon idella) (designated as Ci) injection of grass carp reovirus (GCRV) utilizing quantitative real-time RT-PCR (qRT-PCR). Furthermore, mRNA expression patterns of these genes (IgM excepted) were examined post GCRV infection and polyinosine-polycytidylic acid (poly(I:C)), lipopolysaccharide (LPS) or peptidoglycan (PGN) stimulation in primary trunk kidney cells of grass carp. The relative values of CiTLR3, CiTLR22 and CiMyD88 were increased post GCRV challenge and viral/bacterial PAMPs stimulation. The mRNA transcriptions of CiTLR7 were obviously activated with GCRV challenge. Remarkably, the mRNA expressions of CiRIG-I, CiMDA5, CiLGP2 and CiIPS-1 were largely up-regulated with GCRV challenge and viral/bacterial PAMPs stimulation. Interestingly, the expression tendencies of CiNOD1 and CiNOD2 were differential not only in GCRV challenge and poly(I:C) stimulation, but also in LPS and PGN stimulation. It was demonstrated that CiIFN-I induced powerful anti-viral and anti-bacterial effects in trunk kidney. In addition, the expression of CiIgM was induced at 72 h post GCRV injection in vivo. Collectively, these results suggest that trunk kidney of grass carp serves as an important immune organ, and plays crucial roles in triggering anti-viral and anti-bacterial immune responses both in vivo and in vitro.
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Affiliation(s)
- Lijun Chen
- Northwest A&F University, Shaanxi Key Laboratory of Molecular Biology for Agriculture, College of Animal Science and Technology, No. 22, Xinong Rd., Yangling, Shaanxi Province 712100, China
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136
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Abstract
In this issue of Immunity, Yu et al. (2012) outline a fascinating model in which TLR7-mediated antibody production acts as a dominant immunosurveillance mechanism against endogenous retroviruses (ERVs), with additional support of TLR3 and TLR9 that function to prevent ERV-mediated malignancy.
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Affiliation(s)
- Arun K Mankan
- Institute for Clinical Chemistry and Clinical Pharmacology, University Hospital, University of Bonn, Bonn, Germany
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137
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Abstract
Tetherin (BST2/CD317) has emerged as a key host cell defense molecule, inhibiting the release and spread of diverse enveloped virions from infected cells. In this chapter, I review the molecular and cellular basis for tetherin's antiviral activities and the function of virally encoded countermeasures that disrupt its function. I further describe recent advances in our understanding of tetherin's associated role in viral pattern recognition and the evidence for its role in limiting viral pathogenesis in vivo.
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Affiliation(s)
- Stuart J D Neil
- Department of Infectious Disease, King's College London School of Medicine, London, UK.
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138
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Antiviral immunity: Immune control of endogenous retroviruses. Nat Rev Immunol 2012; 12:805. [PMID: 23175217 DOI: 10.1038/nri3355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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