101
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Miyake K, Shibata T, Ohto U, Shimizu T, Saitoh SI, Fukui R, Murakami Y. Mechanisms controlling nucleic acid-sensing Toll-like receptors. Int Immunol 2018; 30:43-51. [DOI: 10.1093/intimm/dxy016] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Accepted: 02/13/2018] [Indexed: 12/23/2022] Open
Affiliation(s)
- Kensuke Miyake
- Division of Innate Immunity, Department of Microbiology and Immunology, Institute of Medical Science, University of Tokyo, Shirokanedai, Minato-ku, Tokyo, Japan
| | - Takuma Shibata
- Division of Innate Immunity, Department of Microbiology and Immunology, Institute of Medical Science, University of Tokyo, Shirokanedai, Minato-ku, Tokyo, Japan
| | - Umeharu Ohto
- Graduate School of Pharmaceutical Sciences, University of Tokyo, Hongo, Bunkyo-ku, Tokyo, Japan
| | - Toshiyuki Shimizu
- Graduate School of Pharmaceutical Sciences, University of Tokyo, Hongo, Bunkyo-ku, Tokyo, Japan
| | - Shin-Ichiroh Saitoh
- Division of Innate Immunity, Department of Microbiology and Immunology, Institute of Medical Science, University of Tokyo, Shirokanedai, Minato-ku, Tokyo, Japan
| | - Ryutaro Fukui
- Division of Innate Immunity, Department of Microbiology and Immunology, Institute of Medical Science, University of Tokyo, Shirokanedai, Minato-ku, Tokyo, Japan
| | - Yusuke Murakami
- Division of Innate Immunity, Department of Microbiology and Immunology, Institute of Medical Science, University of Tokyo, Shirokanedai, Minato-ku, Tokyo, Japan
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102
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Patra MC, Choi S. Insight into Phosphatidylinositol-Dependent Membrane Localization of the Innate Immune Adaptor Protein Toll/Interleukin 1 Receptor Domain-Containing Adaptor Protein. Front Immunol 2018; 9:75. [PMID: 29434596 PMCID: PMC5796906 DOI: 10.3389/fimmu.2018.00075] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2017] [Accepted: 01/11/2018] [Indexed: 01/23/2023] Open
Abstract
The toll/interleukin 1 receptor (TIR) domain-containing adaptor protein (TIRAP) plays an important role in the toll-like receptor (TLR) 2, TLR4, TLR7, and TLR9 signaling pathways. TIRAP anchors to phosphatidylinositol (PI) 4,5-bisphosphate (PIP2) on the plasma membrane and PI (3,4,5)-trisphosphate (PIP3) on the endosomal membrane and assists in recruitment of the myeloid differentiation primary response 88 protein to activated TLRs. To date, the structure and mechanism of TIRAP’s membrane association are only partially understood. Here, we modeled an all-residue TIRAP dimer using homology modeling, threading, and protein–protein docking strategies. Molecular dynamics simulations revealed that PIP2 creates a stable microdomain in a dipalmitoylphosphatidylcholine bilayer, providing TIRAP with its physiologically relevant orientation. Computed binding free energy values suggest that the affinity of PI-binding domain (PBD) for PIP2 is stronger than that of TIRAP as a whole for PIP2 and that the short PI-binding motif (PBM) contributes to the affinity between PBD and PIP2. Four PIP2 molecules can be accommodated by distinct lysine-rich surfaces on the dimeric PBM. Along with the known PI-binding residues (K15, K16, K31, and K32), additional positively charged residues (K34, K35, and R36) showed strong affinity toward PIP2. Lysine-to-alanine mutations at the PI-binding residues abolished TIRAP’s affinity for PIP2; however, K34, K35, and R36 consistently interacted with PIP2 headgroups through hydrogen bond (H-bond) and electrostatic interactions. TIRAP exhibited a PIP2-analogous intermolecular contact and binding affinity toward PIP3, aided by an H-bond network involving K34, K35, and R36. The present study extends our understanding of TIRAP’s membrane association, which could be helpful in designing peptide decoys to block TLR2-, TLR4-, TLR7-, and TLR9-mediated autoimmune diseases.
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Affiliation(s)
- Mahesh Chandra Patra
- Department of Molecular Science and Technology, Ajou University, Suwon, South Korea
| | - Sangdun Choi
- Department of Molecular Science and Technology, Ajou University, Suwon, South Korea
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103
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Lee C, Lee M, Rhee I. Distinct features of dendritic cell-based immunotherapy as cancer vaccines. Clin Exp Vaccine Res 2018; 7:16-23. [PMID: 29399576 PMCID: PMC5795041 DOI: 10.7774/cevr.2018.7.1.16] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2017] [Revised: 12/22/2017] [Accepted: 12/28/2017] [Indexed: 01/07/2023] Open
Abstract
Dendritic cells (DCs) are the most professional antigen presenting cells that play important roles in connection between innate and adaptive immune responses. Numerous studies revealed that the functions of DCs are related with the capture and processing of antigen as well as the migration to lymphoid tissues for the presenting antigens to T cells. These unique features of DCs allow them to be considered as therapeutic vaccines that can induce immune responses and anti-tumor activity. Here, we discuss and understand the immunological basis of DCs and presume the possibilities of DC-based vaccines for the promising cancer therapy.
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Affiliation(s)
- Chaelin Lee
- Department of Bioscience & Biotechnology, Sejong University, Seoul, Korea
| | - Myungmi Lee
- Department of Bioscience & Biotechnology, Sejong University, Seoul, Korea
| | - Inmoo Rhee
- Department of Bioscience & Biotechnology, Sejong University, Seoul, Korea
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104
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Abstract
Phagosomal compartments are critical in microbial defense as vesicles that degrade invading organisms. In a broader context, vesicular trafficking plays an important role in shuttling many different types of cargo that are critical for proper function of the cell. Endosomal and phagosomal vesicles are thus important locations for the assembly of intracellular signaling platforms that mediate host responses to invasive pathogens such as Borrelia burgdorferi. Isolation of phagosomes from cells is an important technique that allows for a detailed study of phagosomal components and signaling complex assembly. However, purification of phagosomes had previously been challenging and it has been difficult to obtain sufficient purity of the phagosomal fractions. Here, we modify a new magnetic isolation technique that greatly simplifies purification of phagosomes and isolates vesicles with sufficient purity for analysis.
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Affiliation(s)
- Tanja Petnicki-Ocwieja
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, 136 Harrison Avenue, Boston, MA, 02111, USA
| | - Linden T Hu
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, 136 Harrison Avenue, Boston, MA, 02111, USA.
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105
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Abstract
This review introduces recent concepts in innate immunity highlighting some of the latest exciting findings. These include: the discovery of the initiator of pyroptosis, Gasdermin D, and mechanisms of inflammatory caspases in innate immune signaling; the formation of oligomeric signalosomes downstream of innate immune receptors; mechanisms that shape innate immune responses, such as cellular homeostasis, cell metabolism, and pathogen viability; rapid methods of cell-to-cell communication; the interplay between the host and its microbiome and the concept of innate immunological memory. Furthermore, we discuss open questions and illustrate how technological advances, such as CRISPR/Cas9, may provide important answers for outstanding questions in the field of innate immunity.
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Affiliation(s)
- Karin Pelka
- Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA
| | - Dominic De Nardo
- Inflammation Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia. .,Department of Medical Biology, The University of Melbourne, Parkville, Victoria, Australia.
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106
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TLR7 mediated viral recognition results in focal type I interferon secretion by dendritic cells. Nat Commun 2017; 8:1592. [PMID: 29150602 PMCID: PMC5693993 DOI: 10.1038/s41467-017-01687-x] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Accepted: 10/09/2017] [Indexed: 12/17/2022] Open
Abstract
Plasmacytoid dendritic cells (pDC) sense viral RNA through toll-like
receptor 7 (TLR7), form self-adhesive pDC–pDC clusters, and produce type I
interferons. This cell adhesion enhances type I interferon production, but little is
known about the underlying mechanisms. Here we show that MyD88-dependent TLR7
signaling activates CD11a/CD18 integrin to induce microtubule elongation.
TLR7+ lysosomes then become linked with these
microtubules through the GTPase Arl8b and its effector SKIP/Plekhm2, resulting in
perinuclear to peripheral relocalization of TLR7. The type I interferon signaling
molecules TRAF3, IKKα, and mTORC1 are constitutively associated in pDCs. TLR7
localizes to mTORC1 and induces association of TRAF3 with the upstream molecule
TRAF6. Finally, type I interferons are secreted in the vicinity of cell–cell
contacts between clustered pDCs. These results suggest that TLR7 needs to move to
the cell periphery to induce robust type I interferon responses in pDCs. Antiviral immune responses involve clustering of plasmacytoid
dendritic cells (pDC) in response to endosomal TLR7-mediated sensing of viral RNA.
Here the authors show the GTPase Arl8b controls translocation of
TLR7+ endosomes to the periphery of the cell via
microtubule interactions, thus enabling pDC clustering and type I interferon
production.
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107
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Pollard KM, Escalante GM, Huang H, Haraldsson KM, Hultman P, Christy JM, Pawar RD, Mayeux JM, Gonzalez-Quintial R, Baccala R, Beutler B, Theofilopoulos AN, Kono DH. Induction of Systemic Autoimmunity by a Xenobiotic Requires Endosomal TLR Trafficking and Signaling from the Late Endosome and Endolysosome but Not Type I IFN. THE JOURNAL OF IMMUNOLOGY 2017; 199:3739-3747. [PMID: 29055005 DOI: 10.4049/jimmunol.1700332] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Accepted: 09/25/2017] [Indexed: 12/17/2022]
Abstract
Type I IFN and nucleic acid-sensing TLRs are both strongly implicated in the pathogenesis of lupus, with most patients expressing IFN-induced genes in peripheral blood cells and with TLRs promoting type I IFNs and autoreactive B cells. About a third of systemic lupus erythematosus patients, however, lack the IFN signature, suggesting the possibility of type I IFN-independent mechanisms. In this study, we examined the role of type I IFN and TLR trafficking and signaling in xenobiotic systemic mercury-induced autoimmunity (HgIA). Strikingly, autoantibody production in HgIA was not dependent on the type I IFN receptor even in NZB mice that require type I IFN signaling for spontaneous disease, but was dependent on the endosomal TLR transporter UNC93B1 and the endosomal proton transporter, solute carrier family 15, member 4. HgIA also required the adaptor protein-3 complex, which transports TLRs from the early endosome to the late endolysosomal compartments. Examination of TLR signaling pathways implicated the canonical NF-κB pathway and the proinflammatory cytokine IL-6 in autoantibody production, but not IFN regulatory factor 7. These findings identify HgIA as a novel type I IFN-independent model of systemic autoimmunity and implicate TLR-mediated NF-κB proinflammatory signaling from the late endocytic pathway compartments in autoantibody generation.
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Affiliation(s)
- K Michael Pollard
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037;
| | - Gabriela M Escalante
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037
| | - Hua Huang
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA 92037
| | - Katarina M Haraldsson
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA 92037
| | - Per Hultman
- Department of Experimental and Clinical Medicine, Linköping University, Linköping 58183, Sweden; and
| | - Joseph M Christy
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037
| | - Rahul D Pawar
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037
| | - Jessica M Mayeux
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037
| | | | - Roberto Baccala
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA 92037
| | - Bruce Beutler
- Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | | | - Dwight H Kono
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA 92037
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108
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Murayama G, Furusawa N, Chiba A, Yamaji K, Tamura N, Miyake S. Enhanced IFN-α production is associated with increased TLR7 retention in the lysosomes of palasmacytoid dendritic cells in systemic lupus erythematosus. Arthritis Res Ther 2017; 19:234. [PMID: 29052537 PMCID: PMC5649081 DOI: 10.1186/s13075-017-1441-7] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Accepted: 09/21/2017] [Indexed: 01/04/2023] Open
Abstract
Background Interferon-α (IFN-α) is increased and plays an important role in the pathogenesis of systemic lupus erythematosus (SLE). Plasmacytoid dendritic cells (pDCs) are the main producer of IFN-α, but their IFN-α producing capacity has been shown to be unchanged or reduced when stimulated with a Toll-like receptor 9 (TLR9) agonist in patients with SLE compared to in healthy individuals. In this study, we investigated the IFN-α-producing capacity of lupus pDCs under different stimulation. Methods pDCs from patients with SLE and healthy controls (HC) were stimulated with TLR9 or TLR7 agonist, and their IFN-α producing capacity was examined by intracellular cytokine staining and flow cytometry. The correlation of IFN-α-producing capacity with serum IFN-α levels and disease activity was assessed. The effect of in vitro IFN-α exposure on IFN-α production by pDCs was examined. Localization of TLR7 in cellular compartments in pDCs was investigated. Results The IFN-α producing capacity of pDCs was reduced after TLR9 stimulation, but increased when stimulated with a TLR7 agonist in SLE compared to in HC. IFN-α production by pDCs upon TLR9 stimulation was reduced and the percentage of IFN-α+pDC was inversely correlated with disease activity and serum IFN-α levels. However, the TLR7 agonist-induced IFN-α producing capacity of lupus pDCs was enhanced and correlated with disease activity and serum IFN-α. Exposure to IFN-α enhanced IFN-α production of TLR7-stimulated pDCs, but reduced that of pDCs activated with a TLR9 agonist. TLR7 localization was increased in late endosome/lysosome compartments in pDCs from SLE patients. Conclusions These findings indicate that enhanced TLR7 responses of lupus pDCs, owing to TLR7 retention in late endosome/lysosome and exposure to IFN-α, are associated with the pathogenesis of SLE. Electronic supplementary material The online version of this article (doi:10.1186/s13075-017-1441-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Goh Murayama
- Department of Immunology, Juntendo University School of Medicine, 2-2-1 Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan.,Department of Internal Medicine and Rheumatology, Juntendo University School of Medicine, Tokyo, Japan
| | - Nanako Furusawa
- Department of Immunology, Juntendo University School of Medicine, 2-2-1 Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan
| | - Asako Chiba
- Department of Immunology, Juntendo University School of Medicine, 2-2-1 Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan.
| | - Ken Yamaji
- Department of Internal Medicine and Rheumatology, Juntendo University School of Medicine, Tokyo, Japan
| | - Naoto Tamura
- Department of Internal Medicine and Rheumatology, Juntendo University School of Medicine, Tokyo, Japan
| | - Sachiko Miyake
- Department of Immunology, Juntendo University School of Medicine, 2-2-1 Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan.
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109
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Kader M, Alaoui-EL-Azher M, Vorhauer J, Kode BB, Wells JZ, Stolz D, Michalopoulos G, Wells A, Scott M, Ismail N. MyD88-dependent inflammasome activation and autophagy inhibition contributes to Ehrlichia-induced liver injury and toxic shock. PLoS Pathog 2017; 13:e1006644. [PMID: 29049365 PMCID: PMC5663626 DOI: 10.1371/journal.ppat.1006644] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Revised: 10/31/2017] [Accepted: 09/11/2017] [Indexed: 01/19/2023] Open
Abstract
Severe hepatic inflammation is a common cause of acute liver injury following systemic infection with Ehrlichia, obligate Gram-negative intracellular bacteria that lack lipopolysaccharide (LPS). We have previously shown that type I IFN (IFN-I) and inflammasome activation are key host-pathogenic mediators that promote excessive inflammation and liver damage following fatal Ehrlichia infection. However, the underlying signals and mechanisms that regulate protective immunity and immunopathology during Ehrlichia infection are not well understood. To address this issue, we compared susceptibility to lethal Ixodes ovatus Ehrlichia (IOE) infection between wild type (WT) and MyD88-deficient (MyD88-/-) mice. We show here that MyD88-/- mice exhibited decreased inflammasome activation, attenuated liver injury, and were more resistant to lethal infection than WT mice, despite suppressed protective immunity and increased bacterial burden in the liver. MyD88-dependent inflammasome activation was also dependent on activation of the metabolic checkpoint kinase mammalian target of rapamycin complex 1 (mTORC1), inhibition of autophagic flux, and defective mitophagy in macrophages. Blocking mTORC1 signaling in infected WT mice and primary macrophages enhanced bacterial replication and attenuated inflammasome activation, suggesting autophagy promotes bacterial replication while inhibiting inflammasome activation. Finally, our data suggest TLR9 and IFN-I are upstream signaling mechanisms triggering MyD88-mediated mTORC1 and inflammasome activation in macrophages following Ehrlichia infection. This study reveals that Ehrlichia-induced liver injury and toxic shock are mediated by MyD88-dependent inflammasome activation and autophagy inhibition. Human monocytic ehrlichiosis (HME) is the most prevalent emerging infectious disease in the United States. Ehrlichia chaffeensis, etiologic agent of HME, is a Gram negative obligate intracellular bacterium transmitted by infected tick bites and can infect different cell type. Although Ehrlichia lack lipopolysaccharide (LPS), they induce potentially life threatening HME that mimic sepsis or toxic shock associated with multi-organ failure. The clinical diagnosis of HME is difficult, and definitive diagnosis is most often retrospective. Late antibiotic treatment is frequently ineffective in preventing disease progression to fatal multi-organ failure. Liver failure is one of the most serious complications and the most frequent cause of death in patients with HME, however we only have a limited understanding of how this liver failure is caused during fatal Ehrlichia infection. The objective of this study is to determine how LPS-negative Ehrlichia activates inflammatory responses in macrophages during Ehrlichia infection to promote liver damage. We show here that MyD88-signaling causes detrimental derangement of the immune system and subsequent liver damage by regulating two key innate immune events in macrophages: autophagy and inflammasome activation. Targeting host-pathogenic pathways in ehrlichiosis can be incorporated into future design of novel therapeutic approaches for HME.
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MESH Headings
- Animals
- Autophagy/immunology
- Blotting, Western
- Disease Models, Animal
- Ehrlichia/immunology
- Ehrlichiosis/immunology
- Ehrlichiosis/metabolism
- Enzyme-Linked Immunosorbent Assay
- Female
- Flow Cytometry
- Fluorescent Antibody Technique
- Image Processing, Computer-Assisted
- In Situ Nick-End Labeling
- Inflammasomes/immunology
- Inflammasomes/metabolism
- Liver Failure, Acute/immunology
- Liver Failure, Acute/metabolism
- Liver Failure, Acute/microbiology
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Microscopy, Confocal
- Microscopy, Electron, Transmission
- Myeloid Differentiation Factor 88/immunology
- Myeloid Differentiation Factor 88/metabolism
- Real-Time Polymerase Chain Reaction
- Shock, Septic/immunology
- Shock, Septic/metabolism
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Affiliation(s)
- Muhamuda Kader
- Department of Pathology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Mounia Alaoui-EL-Azher
- Department of Pathology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Jennie Vorhauer
- Department of Pathology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Bhushan B Kode
- Department of Pathology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Jakob Z. Wells
- Department of Pathology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Donna Stolz
- Center for Biologic Imaging, University of Pittsburgh Medical School, Pittsburgh, Pennsylvania, United States of America
| | - George Michalopoulos
- Department of Pathology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
- Pittsburgh Liver Research Center, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Alan Wells
- Department of Pathology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
- Pittsburgh Liver Research Center, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Melanie Scott
- Pittsburgh Liver Research Center, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
- Department of Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Nahed Ismail
- Department of Pathology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
- Pittsburgh Liver Research Center, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
- Department of Immunology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
- * E-mail:
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110
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Khatamzas E, Hipp MM, Gaughan D, Pichulik T, Leslie A, Fernandes RA, Muraro D, Booth S, Zausmer K, Sun MY, Kessler B, Rowland-Jones S, Cerundolo V, Simmons A. Snapin promotes HIV-1 transmission from dendritic cells by dampening TLR8 signaling. EMBO J 2017; 36:2998-3011. [PMID: 28923824 PMCID: PMC5641917 DOI: 10.15252/embj.201695364] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Revised: 08/05/2017] [Accepted: 08/11/2017] [Indexed: 12/18/2022] Open
Abstract
HIV-1 traffics through dendritic cells (DCs) en route to establishing a productive infection in T lymphocytes but fails to induce an innate immune response. Within DC endosomes, HIV-1 somehow evades detection by the pattern-recognition receptor (PRR) Toll-like receptor 8 (TLR8). Using a phosphoproteomic approach, we identified a robust and diverse signaling cascade triggered by HIV-1 upon entry into human DCs. A secondary siRNA screen of the identified signaling factors revealed several new mediators of HIV-1 trans-infection of CD4+ T cells in DCs, including the dynein motor protein Snapin. Inhibition of Snapin enhanced localization of HIV-1 with TLR8+ early endosomes, triggered a pro-inflammatory response, and inhibited trans-infection of CD4+ T cells. Snapin inhibited TLR8 signaling in the absence of HIV-1 and is a general regulator of endosomal maturation. Thus, we identify a new mechanism of innate immune sensing by TLR8 in DCs, which is exploited by HIV-1 to promote transmission.
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Affiliation(s)
- Elham Khatamzas
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, Oxford University, Oxford, UK
| | - Madeleine Maria Hipp
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, Oxford University, Oxford, UK
| | - Daniel Gaughan
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, Oxford University, Oxford, UK
| | - Tica Pichulik
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, Oxford University, Oxford, UK
| | - Alasdair Leslie
- KwaZulu-Natal Research Institute for TB & HIV, Durban, South Africa
| | - Ricardo A Fernandes
- Molecular and Cellular Physiology and Structural Biology, Stanford University School of Medicine, Stanford, CA, USA
| | - Daniele Muraro
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, Oxford University, Oxford, UK
| | - Sarah Booth
- Immunology & Immunotherapy, College of Medical & Dental Sciences, University of Birmingham, Birmingham, UK
| | - Kieran Zausmer
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, Oxford University, Oxford, UK
| | - Mei-Yi Sun
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, Oxford University, Oxford, UK
| | - Benedikt Kessler
- KwaZulu-Natal Research Institute for TB & HIV, Durban, South Africa
| | - Sarah Rowland-Jones
- Nuffield Department of Clinical Medicine, University of Oxford NDMRB, Oxford, UK
| | - Vincenzo Cerundolo
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, Oxford University, Oxford, UK
| | - Alison Simmons
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, Oxford University, Oxford, UK
- Translational Gastroenterology Unit, Nuffield Department of Medicine University of Oxford, Oxford, UK
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111
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Combes A, Camosseto V, N'Guessan P, Argüello RJ, Mussard J, Caux C, Bendriss-Vermare N, Pierre P, Gatti E. BAD-LAMP controls TLR9 trafficking and signalling in human plasmacytoid dendritic cells. Nat Commun 2017; 8:913. [PMID: 29030552 PMCID: PMC5640662 DOI: 10.1038/s41467-017-00695-1] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Accepted: 07/20/2017] [Indexed: 12/28/2022] Open
Abstract
Toll-like receptors (TLR) are essential components of the innate immune system. Several accessory proteins, such as UNC93B1, are required for transport and activation of nucleic acid sensing Toll-like receptors in endosomes. Here, we show that BAD-LAMP (LAMP5) controls TLR9 trafficking to LAMP1+ late endosomes in human plasmacytoid dendritic cells (pDC), leading to NF-κB activation and TNF production upon DNA detection. An inducible VAMP3+/LAMP2+/LAMP1- endolysosome compartment exists in pDCs from which TLR9 activation triggers type I interferon expression. BAD-LAMP-silencing enhances TLR9 retention in this compartment and consequent downstream signalling events. Conversely, sustained BAD-LAMP expression in pDCs contributes to their lack of type I interferon production after exposure to a TGF-β-positive microenvironment or isolation from human breast tumours. Hence, BAD-LAMP limits interferon expression in pDCs indirectly, by promoting TLR9 sorting to late endosome compartments at steady state and in response to immunomodulatory cues.TLR9 is highly expressed by plasmacytoid dendritic cells and detects nucleic acids, but to discriminate between host and microbial nucleic acids TLR9 is sorted into different endosomal compartments. Here the authors show that BAD-LAMP limits type 1 interferon responses by sorting TLR9 to late endosomal compartments.
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Affiliation(s)
- Alexis Combes
- Aix Marseille Université, CNRS, INSERM, CIML, 13288, Marseille cedex 9, France
| | - Voahirana Camosseto
- Aix Marseille Université, CNRS, INSERM, CIML, 13288, Marseille cedex 9, France
- International associated laboratory (LIA) CNRS "Mistra", 13288, Marseille cedex 9, France
| | - Prudence N'Guessan
- Aix Marseille Université, CNRS, INSERM, CIML, 13288, Marseille cedex 9, France
| | - Rafael J Argüello
- Aix Marseille Université, CNRS, INSERM, CIML, 13288, Marseille cedex 9, France
| | - Julie Mussard
- Centre Léon Berard, 69373, LYON cedex 08, France
- Université de Lyon, 69373, LYON cedex 08, France
- INSERM U1052, 69373, LYON cedex 08, France
- CNRS UMR5286, 69373, LYON cedex 08, France
| | - Christophe Caux
- Centre Léon Berard, 69373, LYON cedex 08, France
- Université de Lyon, 69373, LYON cedex 08, France
- INSERM U1052, 69373, LYON cedex 08, France
- CNRS UMR5286, 69373, LYON cedex 08, France
| | - Nathalie Bendriss-Vermare
- Centre Léon Berard, 69373, LYON cedex 08, France
- Université de Lyon, 69373, LYON cedex 08, France
- INSERM U1052, 69373, LYON cedex 08, France
- CNRS UMR5286, 69373, LYON cedex 08, France
| | - Philippe Pierre
- Aix Marseille Université, CNRS, INSERM, CIML, 13288, Marseille cedex 9, France
- International associated laboratory (LIA) CNRS "Mistra", 13288, Marseille cedex 9, France
- Institute for Research in Biomedicine-iBiMED and Aveiro Health Sciences Program University of Aveiro, Aveiro, 3810-193, Portugal
| | - Evelina Gatti
- Aix Marseille Université, CNRS, INSERM, CIML, 13288, Marseille cedex 9, France.
- International associated laboratory (LIA) CNRS "Mistra", 13288, Marseille cedex 9, France.
- Institute for Research in Biomedicine-iBiMED and Aveiro Health Sciences Program University of Aveiro, Aveiro, 3810-193, Portugal.
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112
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Phagocytic Receptors Activate Syk and Src Signaling during Borrelia burgdorferi Phagocytosis. Infect Immun 2017; 85:IAI.00004-17. [PMID: 28717031 DOI: 10.1128/iai.00004-17] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2017] [Accepted: 07/10/2017] [Indexed: 11/20/2022] Open
Abstract
Phagocytosis of the Lyme disease-causing pathogen Borrelia burgdorferi has been shown to be important for generating an inflammatory response to the pathogen. As a result, understanding the mechanisms of phagocytosis has been an area of great interest in the field of Lyme disease. Several cell surface receptors that participate in B. burgdorferi phagocytosis have been reported, including the scavenger receptor MARCO and integrin α3β1. We sought to define the mechanisms by which these receptors mediate phagocytosis and to identify signaling pathways activated downstream of these receptors upon contact with B. burgdorferi We identified both Syk and Src signaling pathways as ones that participate in B. burgdorferi phagocytosis and the resulting cytokine activation. In our studies, we found that both MARCO and integrin β1 play a role in the activation of the Src kinase pathway. However, only integrin β1 participates in the activation of Syk. Interestingly, the integrin activates Syk without the help of the signaling adaptor Dap12 or FcRγ. Thus, we report that multiple pathways participate in B. burgdorferi internalization and that different cell surface receptors act simultaneously in cooperation and independently to mediate phagocytosis.
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113
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Petes C, Odoardi N, Gee K. The Toll for Trafficking: Toll-Like Receptor 7 Delivery to the Endosome. Front Immunol 2017; 8:1075. [PMID: 28928743 PMCID: PMC5591332 DOI: 10.3389/fimmu.2017.01075] [Citation(s) in RCA: 108] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Accepted: 08/18/2017] [Indexed: 01/12/2023] Open
Abstract
Toll-like receptor (TLR)-7 is an endosomal innate immune sensor capable of detecting single-stranded ribonucleic acid. TLR7-mediated induction of type I interferon and other inflammatory cytokine production is important in antiviral immune responses. Furthermore, altered TLR7 expression levels are implicated in various autoimmune disorders, indicating a key role for this receptor in modulating inflammation. This review is focused on the regulation of TLR7 expression and localization compared to that of the other endosomal TLRs: TLR3, 8, and 9. Endosomal TLR localization is a tightly controlled and intricate process with some shared components among various TLRs. However, TLR-specific mechanisms must also be in place in order to regulate the induction of pathogen- and cell-specific responses. It is known that TLR7 is shuttled from the endoplasmic reticulum to the endosome via vesicles from the Golgi. Several chaperone proteins are required for this process, most notably uncoordinated 93 homolog B1 (Caenorhabditis elegans), recently identified to also be involved in the localization of the other endosomal TLRs. Acidification of the endosome and proteolytic cleavage of TLR7 are essential for TLR7 signaling in response to ligand binding. Cleavage of TLR7 has been demonstrated to be accomplished by furin peptidases in addition to cathepsins and asparagine endopeptidases. Moreover, triggering receptor expressed on myeloid cells like 4, a protein associated with antigen presentation and apoptosis in immune cells, has been implicated in the amplification of TLR7 signaling. Understanding these and other molecular mechanisms controlling TLR7 expression and trafficking will give insight into the specific control of TLR7 activity compared to the other endosomal TLRs.
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Affiliation(s)
- Carlene Petes
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON, Canada
| | - Natalya Odoardi
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON, Canada
| | - Katrina Gee
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON, Canada
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114
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Akkaya M, Akkaya B, Sheehan PW, Miozzo P, Pena M, Qi CF, Manzella-Lapeira J, Bolland S, Pierce SK. T cell-dependent antigen adjuvanted with DOTAP-CpG-B but not DOTAP-CpG-A induces robust germinal center responses and high affinity antibodies in mice. Eur J Immunol 2017; 47:1890-1899. [PMID: 28762497 DOI: 10.1002/eji.201747113] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Revised: 07/11/2017] [Accepted: 07/28/2017] [Indexed: 12/12/2022]
Abstract
The development of vaccines for infectious diseases for which we currently have none, including HIV, will likely require the use of adjuvants that strongly promote germinal center responses and somatic hypermutation to produce broadly neutralizing antibodies. Here we compared the outcome of immunization with the T-cell dependent antigen, NP-conjugated to chicken gamma globulin (NP-CGG) adjuvanted with the toll-like receptor 9 (TLR9) ligands, CpG-A or CpG-B, alone or conjugated with the cationic lipid carrier, DOTAP. We provide evidence that only NP-CGG adjuvanted with DOTAP-CpG-B was an effective vaccine in mice resulting in robust germinal center responses, isotype switching and high affinity NP-specific antibodies. The effectiveness of DOTAP-CpG-B as an adjuvant was dependent on the expression of the TLR9 signaling adaptor MyD88 in immunized mice. These results indicate DOTAP-CpG-B but not DOTAP-CpG-A is an effective adjuvant for T cell-dependent protein antigen-based vaccines.
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Affiliation(s)
- Munir Akkaya
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA
| | - Billur Akkaya
- Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Patrick W Sheehan
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA
| | - Pietro Miozzo
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA
| | - Mirna Pena
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA
| | - Chen-Feng Qi
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA
| | - Javier Manzella-Lapeira
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA
| | - Silvia Bolland
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA
| | - Susan K Pierce
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA
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115
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Abstract
Helicobacter pylori is the most common bacterial infection worldwide, and virtually all infected persons develop co-existing gastritis. H. pylori is able to send and receive signals from the gastric mucosa, which enables both host and microbe to engage in a dynamic equilibrium. In order to persist within the human host, H. pylori has adopted dichotomous strategies to both induce inflammation as a means of liberating nutrients while simultaneously tempering the immune response to augment its survival. Toll-like receptors (TLRs) and Nod proteins are innate immune receptors that are present in epithelial cells and represent the first line of defense against pathogens. To ensure persistence, H. pylori manipulates TLR-mediated defenses using strategies that include rendering its LPS and flagellin to be non-stimulatory to TLR4 and TLR5, respectively; translocating peptidoglycan into host cells to induce NOD1-mediated anti-inflammatory responses; and translocating DNA into host cells to induce TLR9 activation.
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116
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Akkaya M, Akkaya B, Miozzo P, Rawat M, Pena M, Sheehan PW, Kim AS, Kamenyeva O, Kabat J, Bolland S, Chaturvedi A, Pierce SK. B Cells Produce Type 1 IFNs in Response to the TLR9 Agonist CpG-A Conjugated to Cationic Lipids. THE JOURNAL OF IMMUNOLOGY 2017; 199:931-940. [PMID: 28652397 DOI: 10.4049/jimmunol.1700348] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Accepted: 05/31/2017] [Indexed: 11/19/2022]
Abstract
B cells express the innate receptor, TLR9, which signals in response to unmethylated CpG sequences in microbial DNA. Of the two major classes of CpG-containing oligonucleotides, CpG-A appears restricted to inducing type 1 IFN in innate immune cells and CpG-B to activating B cells to proliferate and produce Abs and inflammatory cytokines. Although CpGs are candidates for adjuvants to boost innate and adaptive immunity, our understanding of the effect of CpG-A and CpG-B on B cell responses is incomplete. In this study we show that both CpG-B and CpG-A activated B cells in vitro to proliferate, secrete Abs and IL-6, and that neither CpG-B nor CpG-A alone induced type 1 IFN production. However, when incorporated into the cationic lipid, DOTAP, CpG-A, but not CpG-B, induced a type 1 IFN response in B cells in vitro and in vivo. We provide evidence that differences in the function of CpG-A and CpG-B may be related to their intracellular trafficking in B cells. These findings fill an important gap in our understanding of the B cell response to CpGs, with implications for the use of CpG-A and CpG-B as immunomodulators.
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Affiliation(s)
- Munir Akkaya
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD 20852;
| | - Billur Akkaya
- Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Pietro Miozzo
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD 20852
| | - Mukul Rawat
- Indian Institute of Science Education and Research, Pune 411 008, India; and
| | - Mirna Pena
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD 20852
| | - Patrick W Sheehan
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD 20852
| | - Ann S Kim
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD 20852
| | - Olena Kamenyeva
- Biological Imaging Facility, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Juraj Kabat
- Biological Imaging Facility, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Silvia Bolland
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD 20852
| | - Akanksha Chaturvedi
- Indian Institute of Science Education and Research, Pune 411 008, India; and
| | - Susan K Pierce
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD 20852;
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117
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Oosenbrug T, van de Graaff MJ, Ressing ME, van Kasteren SI. Chemical Tools for Studying TLR Signaling Dynamics. Cell Chem Biol 2017. [PMID: 28648377 DOI: 10.1016/j.chembiol.2017.05.022] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The detection of infectious pathogens is essential for the induction of antimicrobial immune responses. The innate immune system detects a wide array of microbes using a limited set of pattern-recognition receptors (PRRs). One family of PRRs with a central role in innate immunity are the Toll-like receptors (TLRs). Upon ligation, these receptors initiate signaling pathways culminating in the release of pro-inflammatory cytokines and/or type I interferons (IFN-I). In recent years, it has become evident that the specific subcellular location and timing of TLR activation affect signaling outcome. The subtlety of this signaling has led to a growing demand for chemical tools that provide the ability to conditionally control TLR activation. In this review, we survey current models for TLR signaling in time and space, discuss how chemical tools have contributed to our understanding of TLR ligands, and describe how they can aid further elucidation of the dynamic aspects of TLR signaling.
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Affiliation(s)
- Timo Oosenbrug
- Department of Molecular Cell Biology, Leiden University Medical Center, Einthovenweg 20, 2333 ZC Leiden, Zuid-Holland, the Netherlands
| | - Michel J van de Graaff
- Department of Bio-organic Synthesis, Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333 CC Leiden, Zuid-Holland, the Netherlands
| | - Maaike E Ressing
- Department of Molecular Cell Biology, Leiden University Medical Center, Einthovenweg 20, 2333 ZC Leiden, Zuid-Holland, the Netherlands.
| | - Sander I van Kasteren
- Department of Bio-organic Synthesis, Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333 CC Leiden, Zuid-Holland, the Netherlands.
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118
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Plasmacytoid and conventional dendritic cells cooperate in crosspriming AAV capsid-specific CD8 + T cells. Blood 2017; 129:3184-3195. [PMID: 28468798 DOI: 10.1182/blood-2016-11-751040] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Accepted: 05/01/2017] [Indexed: 02/06/2023] Open
Abstract
Adeno-associated virus (AAV) is a replication-deficient parvovirus that is extensively used as a gene therapy vector. CD8+ T-cell responses against the AAV capsid protein can, however, affect therapeutic efficacy. Little is known about the in vivo mechanism that leads to the crosspriming of CD8+ T cells against the input viral capsid antigen. In this study, we report that the Toll-like receptor 9 (TLR9)-MyD88 pattern-recognition receptor pathway is uniquely capable of initiating this response. By contrast, the absence of TLR2, STING, or the addition of TLR4 agonist has no effect. Surprisingly, both conventional dendritic cells (cDCs) and plasmacytoid DCs (pDCs) are required for the crosspriming of capsid-specific CD8+ T cells, whereas other antigen-presenting cells are not involved. TLR9 signaling is specifically essential in pDCs but not in cDCs, indicating that sensing of the viral genome by pDCs activates cDCs in trans to cross-present capsid antigen during CD8+ T-cell activation. Cross-presentation and crosspriming depend not only on TLR9, but also on interferon type I signaling, and both mechanisms can be inhibited by administering specific molecules to prevent induction of capsid-specific CD8+ T cells. Thus, these outcomes directly point to therapeutic interventions and demonstrate that innate immune blockade can eliminate unwanted immune responses in gene therapy.
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119
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Hirsch I, Janovec V, Stranska R, Bendriss-Vermare N. Cross Talk between Inhibitory Immunoreceptor Tyrosine-Based Activation Motif-Signaling and Toll-Like Receptor Pathways in Macrophages and Dendritic Cells. Front Immunol 2017; 8:394. [PMID: 28439271 PMCID: PMC5383719 DOI: 10.3389/fimmu.2017.00394] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2017] [Accepted: 03/21/2017] [Indexed: 01/12/2023] Open
Abstract
The innate immune cells sense microbial infection and self-ligands by pathogen recognition receptors (PRRs), such as toll-like receptors (TLRs) and regulatory receptors (RRs), associated with immunoreceptor tyrosine-based activation motif (ITAM). Rapid activation and concerted action of PRRs signaling and feedback inhibitory mechanisms must be engaged to ensure the host defense functions and to prevent cytotoxicity associated with excessive activation. ITAM-associated RRs can generate stimulatory or, paradoxically, inhibitory signals. The network of ITAM-associated RR, together with TLR-signaling pathways, are responsible for immunogenic or tolerogenic responses of macrophages and dendritic cells to their microenvironment. In macrophages, TLR4 signaling is inhibited by low-avidity ligation of ITAM-associated receptors, while high-avidity ligation of ITAM-associated receptors results in potentiation of TLR4 signaling together with resistance to extracellular cytokine microenvironment signals. In contrast to macrophages, TLR7/9 signaling in plasmacytoid DCs (pDCs) is inhibited by high-avidity ligation of ITAM-associated RR, while low-avidity ligation does not show any effect. Surprisingly, interference of ITAM-associated receptor signaling with TLR pathways has not been reported in conventional dendritic cells. Here, we present an overview of molecular mechanisms acting at the crossroads of TLR and ITAM-signaling pathways and address the question of how the high-avidity engagement of the ITAM-associated receptors in pDCs inhibits TLR7/9 signaling. Cellular context and spatiotemporal engagement of ITAM- and TLR-signaling pathways are responsible for different outcomes of macrophage versus pDC activation. While the cross-regulation of cytokine and TLR signaling, together with antigen presentation, are the principal functions of ITAM-associated RR in macrophages, the major role of these receptors in pDCs seems to be related to inhibition of cytokine production and reestablishment of a tolerogenic state following pDC activation. Pharmacologic targeting of TLR and ITAM signaling could be an attractive new therapeutic approach for treatment of chronic infections, cancer, and autoimmune and inflammatory diseases related to pDCs.
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Affiliation(s)
- Ivan Hirsch
- Faculty of Science, Charles University, Prague, Czech Republic.,Institute of Molecular Genetics, ASCR, Prague, Czech Republic.,Institute of Organic Chemistry and Biochemistry, ASCR, Prague, Czech Republic.,Cancer Research Center Marseille, INSERM U 1068, CNRS, UMR7258, Marseille, France.,Institut Paoli-Calmettes, Aix-Marseille University, Marseille, France
| | - Vaclav Janovec
- Faculty of Science, Charles University, Prague, Czech Republic.,Institute of Molecular Genetics, ASCR, Prague, Czech Republic.,Institute of Organic Chemistry and Biochemistry, ASCR, Prague, Czech Republic
| | - Ruzena Stranska
- Cancer Research Center Marseille, INSERM U 1068, CNRS, UMR7258, Marseille, France.,Institut Paoli-Calmettes, Aix-Marseille University, Marseille, France
| | - Nathalie Bendriss-Vermare
- INSERM 1052, CNRS 5286, Centre Léon Bérard, Centre de Recherche en Cancérologie de Lyon, Univ Lyon, Université Claude Bernard Lyon 1, Lyon, France
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120
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Dallari S, Macal M, Loureiro ME, Jo Y, Swanson L, Hesser C, Ghosh P, Zuniga EI. Src family kinases Fyn and Lyn are constitutively activated and mediate plasmacytoid dendritic cell responses. Nat Commun 2017; 8:14830. [PMID: 28368000 PMCID: PMC5382270 DOI: 10.1038/ncomms14830] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Accepted: 02/03/2017] [Indexed: 12/19/2022] Open
Abstract
Plasmacytoid dendritic cells (pDC) are type I interferon-producing cells with critical functions in a number of human illnesses; however, their molecular regulation is incompletely understood. Here we show the role of Src family kinases (SFK) in mouse and human pDCs. pDCs express Fyn and Lyn and their activating residues are phosphorylated both before and after Toll-like receptor (TLR) stimulation. Fyn or Lyn genetic ablation as well as treatment with SFK inhibitors ablate pDC (but not conventional DC) responses both in vitro and in vivo. Inhibition of SFK activity not only alters TLR-ligand localization and inhibits downstream signalling events, but, independent of ex-vivo TLR stimulation, also affects constitutive phosphorylation of BCAP, an adaptor protein bridging PI3K and TLR pathways. Our data identify Fyn and Lyn as important factors that promote pDC responses, describe the mechanisms involved and highlight a tonic SFK-mediated signalling that precedes pathogen encounter, raising the possibility that small molecules targeting SFKs could modulate pDC responses in human diseases.
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Affiliation(s)
- S Dallari
- Molecular Biology Section, Division of Biological Sciences, University of California, 9500 Gilman Dr La Jolla, San Diego, California 92093, USA
| | - M Macal
- Molecular Biology Section, Division of Biological Sciences, University of California, 9500 Gilman Dr La Jolla, San Diego, California 92093, USA
| | - M E Loureiro
- Molecular Biology Section, Division of Biological Sciences, University of California, 9500 Gilman Dr La Jolla, San Diego, California 92093, USA
| | - Y Jo
- Molecular Biology Section, Division of Biological Sciences, University of California, 9500 Gilman Dr La Jolla, San Diego, California 92093, USA
| | - L Swanson
- Departments of Medicine and Cellular and Molecular Medicine, University of California, 9500 Gilman Dr La Jolla, San Diego, California 92093, USA
| | - C Hesser
- Molecular Biology Section, Division of Biological Sciences, University of California, 9500 Gilman Dr La Jolla, San Diego, California 92093, USA
| | - P Ghosh
- Departments of Medicine and Cellular and Molecular Medicine, University of California, 9500 Gilman Dr La Jolla, San Diego, California 92093, USA
| | - E I Zuniga
- Molecular Biology Section, Division of Biological Sciences, University of California, 9500 Gilman Dr La Jolla, San Diego, California 92093, USA
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121
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The innate immune system in human systemic lupus erythematosus. Clin Sci (Lond) 2017; 131:625-634. [DOI: 10.1042/cs20160415] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Revised: 12/24/2016] [Accepted: 01/11/2017] [Indexed: 12/27/2022]
Abstract
Although the role of adaptive immune mechanisms, e.g. autoantibody formation and abnormal T-cell activation, has been long noted in the pathogenesis of human systemic lupus erythematosus (SLE), the role of innate immunity has been less well characterized. An intricate interplay between both innate and adaptive immune elements exists in protective anti-infective immunity as well as in detrimental autoimmunity. More recently, it has become clear that the innate immune system in this regard not only starts inflammation cascades in SLE leading to disease flares, but also continues to fuel adaptive immune responses throughout the course of the disease. This is why targeting the innate immune system offers an additional means of treating SLE. First trials assessing the efficacy of anti-type I interferon (IFN) therapy or modulators of pattern recognition receptor (PRR) signalling have been attempted. In this review, we summarize the available evidence on the role of several distinct innate immune elements, especially neutrophils and dendritic cells as well as the IFN system, as well as specific innate PRRs along with their signalling pathways. Finally, we highlight recent clinical trials in SLE addressing one or more of the aforementioned components of the innate immune system.
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122
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Sindhava VJ, Oropallo MA, Moody K, Naradikian M, Higdon LE, Zhou L, Myles A, Green N, Nündel K, Stohl W, Schmidt AM, Cao W, Dorta-Estremera S, Kambayashi T, Marshak-Rothstein A, Cancro MP. A TLR9-dependent checkpoint governs B cell responses to DNA-containing antigens. J Clin Invest 2017; 127:1651-1663. [PMID: 28346226 DOI: 10.1172/jci89931] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Accepted: 01/26/2017] [Indexed: 01/07/2023] Open
Abstract
Mature B cell pools retain a substantial proportion of polyreactive and self-reactive clonotypes, suggesting that activation checkpoints exist to reduce the initiation of autoreactive B cell responses. Here, we have described a relationship among the B cell receptor (BCR), TLR9, and cytokine signals that regulate B cell responses to DNA-containing antigens. In both mouse and human B cells, BCR ligands that deliver a TLR9 agonist induce an initial proliferative burst that is followed by apoptotic death. The latter mechanism involves p38-dependent G1 cell-cycle arrest and subsequent intrinsic mitochondrial apoptosis and is shared by all preimmune murine B cell subsets and CD27- human B cells. Survival or costimulatory signals rescue B cells from this fate, but the outcome varies depending on the signals involved. B lymphocyte stimulator (BLyS) engenders survival and antibody secretion, whereas CD40 costimulation with IL-21 or IFN-γ promotes a T-bet+ B cell phenotype. Finally, in vivo immunization studies revealed that when protein antigens are conjugated with DNA, the humoral immune response is blunted and acquires features associated with T-bet+ B cell differentiation. We propose that this mechanism integrating BCR, TLR9, and cytokine signals provides a peripheral checkpoint for DNA-containing antigens that, if circumvented by survival and differentiative cues, yields B cells with the autoimmune-associated T-bet+ phenotype.
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123
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IRAP + endosomes restrict TLR9 activation and signaling. Nat Immunol 2017; 18:509-518. [PMID: 28319098 DOI: 10.1038/ni.3711] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Accepted: 02/14/2017] [Indexed: 12/16/2022]
Abstract
The retention of intracellular Toll-like receptors (TLRs) in the endoplasmic reticulum prevents their activation under basal conditions. TLR9 is activated by sensing ligands in specific endosomal-lysosomal compartments. Here we identified IRAP+ endosomes as major cellular compartments for the early steps of TLR9 activation in dendritic cells (DCs). Both TLR9 and its ligand, the dinucleotide CpG, were present as cargo in IRAP+ endosomes. In the absence of the aminopeptidase IRAP, the trafficking of CpG and TLR9 to lysosomes and signaling via TLR9 were enhanced in DCs and in mice following bacterial infection. IRAP stabilized CpG-containing endosomes by interacting with the actin-nucleation factor FHOD4, which slowed the trafficking of TLR9 toward lysosomes. Thus, endosomal retention of TLR9 via the interaction of IRAP with the actin cytoskeleton is a mechanism that prevents hyper-activation of TLR9 in DCs.
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124
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The protective effect of the anti-Toll-like receptor 9 antibody against acute cytokine storm caused by immunostimulatory DNA. Sci Rep 2017; 7:44042. [PMID: 28266597 PMCID: PMC5339793 DOI: 10.1038/srep44042] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Accepted: 02/02/2017] [Indexed: 02/03/2023] Open
Abstract
Toll-like Receptor 9 (TLR9) is an innate immune receptor recognizing microbial DNA. TLR9 is also activated by self-derived DNA, such as mitochondrial DNA, in a variety of inflammatory diseases. We show here that TLR9 activation in vivo is controlled by an anti-TLR9 monoclonal Ab (mAb). A newly established mAb, named NaR9, clearly detects endogenous TLR9 expressed in primary immune cells. The mAb inhibited TLR9-dependent cytokine production in vitro by bone marrow-derived macrophages and conventional dendritic cells. Furthermore, NaR9 treatment rescued mice from fulminant hepatitis caused by administering the TLR9 ligand CpGB and D-(+)-galactosamine. The production of proinflammatory cytokines induced by CpGB and D-(+)-galactosamine was significantly impaired by the mAb. These results suggest that a mAb is a promising tool for therapeutic intervention in TLR9-dependent inflammatory diseases.
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125
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Martínez-Campos C, Burguete-García AI, Madrid-Marina V. Role of TLR9 in Oncogenic Virus-Produced Cancer. Viral Immunol 2017; 30:98-105. [DOI: 10.1089/vim.2016.0103] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Affiliation(s)
- Cecilia Martínez-Campos
- Dirección de Infecciones Crónicas y Cáncer, Centro de Investigación Sobre Enfermedades Infecciosas, Instituto Nacional de Salud Pública, Cuernavaca, Morelos, Mexico
| | - Ana I. Burguete-García
- Dirección de Infecciones Crónicas y Cáncer, Centro de Investigación Sobre Enfermedades Infecciosas, Instituto Nacional de Salud Pública, Cuernavaca, Morelos, Mexico
| | - Vicente Madrid-Marina
- Dirección de Infecciones Crónicas y Cáncer, Centro de Investigación Sobre Enfermedades Infecciosas, Instituto Nacional de Salud Pública, Cuernavaca, Morelos, Mexico
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126
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Boyapati RK, Tamborska A, Dorward DA, Ho GT. Advances in the understanding of mitochondrial DNA as a pathogenic factor in inflammatory diseases. F1000Res 2017; 6:169. [PMID: 28299196 PMCID: PMC5321122 DOI: 10.12688/f1000research.10397.1] [Citation(s) in RCA: 106] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 02/17/2017] [Indexed: 01/04/2023] Open
Abstract
Mitochondrial DNA (mtDNA) has many similarities with bacterial DNA because of their shared common ancestry. Increasing evidence demonstrates mtDNA to be a potent danger signal that is recognised by the innate immune system and can directly modulate the inflammatory response. In humans, elevated circulating mtDNA is found in conditions with significant tissue injury such as trauma and sepsis and increasingly in chronic organ-specific and systemic illnesses such as steatohepatitis and systemic lupus erythematosus. In this review, we examine our current understanding of mtDNA-mediated inflammation and how the mechanisms regulating mitochondrial homeostasis and mtDNA release represent exciting and previously under-recognised important factors in many human inflammatory diseases, offering many new translational opportunities.
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Affiliation(s)
- Ray K Boyapati
- MRC Centre for Inflammation Research Queens Medical Research Institute, University of Edinburgh, 47 Little France Crescent, Edinburgh, EH16 4TJ, UK; Department of Gastroenterology, Monash Health, Clayton, VIC, Australia
| | - Arina Tamborska
- MRC Centre for Inflammation Research Queens Medical Research Institute, University of Edinburgh, 47 Little France Crescent, Edinburgh, EH16 4TJ, UK
| | - David A Dorward
- MRC Centre for Inflammation Research Queens Medical Research Institute, University of Edinburgh, 47 Little France Crescent, Edinburgh, EH16 4TJ, UK
| | - Gwo-Tzer Ho
- MRC Centre for Inflammation Research Queens Medical Research Institute, University of Edinburgh, 47 Little France Crescent, Edinburgh, EH16 4TJ, UK
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127
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Abstract
DNA vaccines offer many advantages over other anti-tumor vaccine approaches due to their simplicity, ease of manufacturing, and safety. Results from several clinical trials in patients with cancer have demonstrated that DNA vaccines are safe and can elicit immune responses. However, to date few DNA vaccines have progressed beyond phase I clinical trial evaluation. Studies into the mechanism of action of DNA vaccines in terms of antigen-presenting cell types able to directly present or cross-present DNA-encoded antigens, and the activation of innate immune responses due to DNA itself, have suggested opportunities to increase the immunogenicity of these vaccines. In addition, studies into the mechanisms of tumor resistance to anti-tumor vaccination have suggested combination approaches that can increase the anti-tumor effect of DNA vaccines. This review focuses on these mechanisms of action and mechanisms of resistance using DNA vaccines, and how this information is being used to improve the anti-tumor effect of DNA vaccines. These approaches are then specifically discussed in the context of human prostate cancer, a disease for which DNA vaccines have been and continue to be explored as treatments.
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Affiliation(s)
- Christopher D Zahm
- Carbone Cancer Center, University of Wisconsin-Madison, Madison, WI 53705, United States
| | - Viswa Teja Colluru
- Carbone Cancer Center, University of Wisconsin-Madison, Madison, WI 53705, United States
| | - Douglas G McNeel
- Carbone Cancer Center, University of Wisconsin-Madison, Madison, WI 53705, United States.
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128
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Bercusson A, de Boer L, Armstrong-James D. Endosomal sensing of fungi: current understanding and emerging concepts. Med Mycol 2017; 55:10-15. [PMID: 27596144 DOI: 10.1093/mmy/myw072] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Revised: 05/01/2016] [Accepted: 07/08/2016] [Indexed: 12/25/2022] Open
Abstract
Endosomal sensing represents a key strategy by which mammalian cells detect parasitization by invading pathogens. This is critical for the control of fungal pathogens, which are for the most part phagocytosed by effector cells of the innate immune system. Despite rapid overall progress in our understanding of endosomal responses in recent times, relatively little is known about how the endosomal sensing system detects fungi and the ensuing immunological consequences. Considering that many fungal pathogens must overcome and evade endosomal killing in order to survive in the host, understanding this key area of the early innate response is crucial for our understanding of fungal infection. In this review we present a summary of our current knowledge of endosomal sensing within the context of fungal pathogens, with a focus on the myeloid compartment.
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Affiliation(s)
- Amelia Bercusson
- Fungal Pathogens Laboratory, National Heart and Lung Institute, Imperial College London, London UK SW7 6NP
| | - Leon de Boer
- Fungal Pathogens Laboratory, National Heart and Lung Institute, Imperial College London, London UK SW7 6NP
| | - Darius Armstrong-James
- Fungal Pathogens Laboratory, National Heart and Lung Institute, Imperial College London, London UK SW7 6NP
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129
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Tan Y, Kagan JC. Microbe-inducible trafficking pathways that control Toll-like receptor signaling. Traffic 2017; 18:6-17. [PMID: 27731905 PMCID: PMC5182131 DOI: 10.1111/tra.12454] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Revised: 10/07/2016] [Accepted: 10/07/2016] [Indexed: 12/12/2022]
Abstract
The receptors of the mammalian innate immune system are designed for rapid microbial detection, and are located in organelles that are conducive to serve these needs. However, emerging evidence indicates that the sites of microbial detection are not the sites of innate immune signal transduction. Rather, microbial detection triggers the movement of receptors to regions of the cell where factors called sorting adaptors detect active receptors and promote downstream inflammatory responses. These findings highlight the critical role that membrane trafficking pathways play in the initiation of innate immunity to infection. In this review, we describe pathways that promote the microbe-inducible endocytosis of Toll-like receptors (TLRs), and the microbe-inducible movement of TLRs between intracellular compartments. We highlight a new class of proteins called Transporters Associated with the eXecution of Inflammation (TAXI), which have the unique ability to transport TLRs and their microbial ligands to signaling-competent regions of the cell, and we discuss the means by which the subcellular sites of signal transduction are defined.
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Affiliation(s)
- Yunhao Tan
- Harvard Medical School and Division of Gastroenterology, Boston Children’s Hospital, Boston, MA, 02115, USA
| | - Jonathan C. Kagan
- Harvard Medical School and Division of Gastroenterology, Boston Children’s Hospital, Boston, MA, 02115, USA
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130
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Majer O, Liu B, Barton GM. Nucleic acid-sensing TLRs: trafficking and regulation. Curr Opin Immunol 2016; 44:26-33. [PMID: 27907816 DOI: 10.1016/j.coi.2016.10.003] [Citation(s) in RCA: 90] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Accepted: 10/28/2016] [Indexed: 12/11/2022]
Abstract
Toll-like receptors (TLRs) play an important role in innate immune responses against pathogenic microorganisms or tissue damage. Nucleic acid (NA)-sensing TLRs localize in intracellular vesicular compartments and recognize foreign-derived and host-derived nucleic acid ligands. Inappropriate activation of NA-sensing TLRs can cause pathogenic inflammation and autoimmunity. Multiple regulatory mechanisms exist to limit recognition of self-NAs. This review summarizes recent progress that has been made in understanding how NA-sensing TLRs are regulated via trafficking, proteolytic cleavage, as well as ligand processing and recognition.
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Affiliation(s)
- Olivia Majer
- Division of Immunology & Pathogenesis, Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, United States
| | - Bo Liu
- Division of Immunology & Pathogenesis, Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, United States
| | - Gregory M Barton
- Division of Immunology & Pathogenesis, Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, United States
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131
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Panda SK, Kolbeck R, Sanjuan MA. Plasmacytoid dendritic cells in autoimmunity. Curr Opin Immunol 2016; 44:20-25. [PMID: 27855321 DOI: 10.1016/j.coi.2016.10.006] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Accepted: 10/28/2016] [Indexed: 11/30/2022]
Abstract
Plasmacytoid dendritic cells (pDC) is a unique cell population that produces large amounts of type I interferon upon recognition of nucleic acids placing them at the crossroad of both innate and adaptive immunity. Their ability to produce interferon makes them central to anti-viral responses. They are also responsive to circulating autoantibodies bound to nuclear antigens and in that scenario the release of interferons initiate self-directed immune responses. There are now a growing number of autoimmune disorders where unabated activation of pDC is suspected to be pathogenic. Here, we discuss the different mechanisms responsible for breaking tolerance to self-nucleic acids by pDC, including the novel role of IgE autoantibodies in systemic lupus erythematosus. We also summarized the recent progress on therapies undergoing clinical testing that target either pDC or type I interferons.
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Affiliation(s)
- Santosh K Panda
- Dept of Respiratory, Inflammation & Autoimmunity, MedImmune LLC, Gaithersburg, MD, USA
| | - Roland Kolbeck
- Dept of Respiratory, Inflammation & Autoimmunity, MedImmune LLC, Gaithersburg, MD, USA
| | - Miguel A Sanjuan
- Dept of Respiratory, Inflammation & Autoimmunity, MedImmune LLC, Gaithersburg, MD, USA.
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132
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Abstract
As it is a hard-wired system for responses to microbes, innate immunity is particularly susceptible to classical genetic analysis. Mutations led the way to the discovery of many of the molecular elements of innate immune sensing and signaling pathways. In turn, the need for a faster way to find the molecular causes of mutation-induced phenotypes triggered a huge transformation in forward genetics. During the 1980s and 1990s, many heritable phenotypes were ascribed to mutations through positional cloning. In mice, this required three steps. First, a genetic mapping step was used to show that a given phenotype emanated from a circumscribed region of the genome. Second, a physical mapping step was undertaken, in which all of the region was cloned and its gene content determined. Finally, a concerted search for the mutation was performed. Such projects usually lasted for several years, but could produce breakthroughs in our understanding of biological processes. Publication of the annotated mouse genome sequence in 2002 made physical mapping unnecessary. More recently we devised a new technology for automated genetic mapping, which eliminated both genetic mapping and the search for mutations among candidate genes. The cause of phenotype can now be determined instantaneously. We have created more than 100,000 coding/splicing mutations. And by screening for defects of innate and adaptive immunity we have discovered many "new" proteins needed for innate immune function.
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Affiliation(s)
- Bruce Beutler
- Center for the Genetics of Host Defense, UT Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-8505, United States.
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133
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Moretti J, Blander JM. Cell-autonomous stress responses in innate immunity. J Leukoc Biol 2016; 101:77-86. [PMID: 27733577 DOI: 10.1189/jlb.2mr0416-201r] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Revised: 08/10/2016] [Accepted: 08/24/2016] [Indexed: 12/12/2022] Open
Abstract
The innate immune response of phagocytes to microbes has long been known to depend on the core signaling cascades downstream of pattern recognition receptors (PRRs), which lead to expression and production of inflammatory cytokines that counteract infection and induce adaptive immunity. Cell-autonomous responses have recently emerged as important mechanisms of innate immunity. Either IFN-inducible or constitutive, these processes aim to guarantee cell homeostasis but have also been shown to modulate innate immune response to microbes and production of inflammatory cytokines. Among these constitutive cell-autonomous responses, autophagy is prominent and its role in innate immunity has been well characterized. Other stress responses, such as metabolic stress, the ER stress/unfolded protein response, mitochondrial stress, or the DNA damage response, seem to also be involved in innate immunity, although the precise mechanisms by which they regulate the innate immune response are not yet defined. Of importance, these distinct constitutive cell-autonomous responses appear to be interconnected and can also be modulated by microbes and PRRs, which add further complexity to the interplay between innate immune signaling and cell-autonomous responses in the mediation of an efficient innate immune response.
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Affiliation(s)
- Julien Moretti
- Immunology Institute, Icahn School of Medicine at Mount Sinai, New York, New York, USA.,Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - J Magarian Blander
- Immunology Institute, Icahn School of Medicine at Mount Sinai, New York, New York, USA; .,Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA.,The Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, New York, USA.,Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, New York, USA.,Graduate School of Biological Sciences, Icahn School of Medicine at Mount Sinai, New York, New York, USA
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134
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Pelka K, Shibata T, Miyake K, Latz E. Nucleic acid-sensing TLRs and autoimmunity: novel insights from structural and cell biology. Immunol Rev 2016; 269:60-75. [PMID: 26683145 DOI: 10.1111/imr.12375] [Citation(s) in RCA: 83] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Invasion of pathogenic microorganisms or tissue damage activates innate immune signaling receptors that sample subcellular locations for foreign molecular structures, altered host molecules, or signs of compartment breaches. Upon engagement of innate immune receptors an acute but transient inflammatory response is initiated, aimed at the clearance of pathogens and cellular debris. Among the molecules that are sensed are nucleic acids, which activate several members of the transmembrane Toll-like receptor (TLR) family. Inappropriate recognition of nucleic acids by TLRs can cause inflammatory pathologies and autoimmunity. Here, we review the mechanisms involved in triggering nucleic acid-sensing TLRs and indicate checkpoints that restrict their activation to endolysosomal compartments. These mechanisms are crucial to sample the content of endosomes for nucleic acids in the context of infection or tissue damage, yet prevent accidental activation by host nucleic acids under physiological conditions. Decoding the molecular mechanisms that regulate nucleic acid recognition by TLRs is central to understand pathologies linked to unrestricted nucleic acid sensing and to develop novel therapeutic strategies.
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Affiliation(s)
- Karin Pelka
- Institute of Innate Immunity, University Hospitals Bonn, Bonn, Germany
| | - Takuma Shibata
- Department of Microbiology and Immunology, Institute of Medical Science, University of Tokyo, Tokyo, Japan.,Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Tokyo, Japan
| | - Kensuke Miyake
- Department of Microbiology and Immunology, Institute of Medical Science, University of Tokyo, Tokyo, Japan
| | - Eicke Latz
- Institute of Innate Immunity, University Hospitals Bonn, Bonn, Germany.,German Center for Neurodegenerative Diseases, Bonn, Germany.,Department of Medicine, University of Massachusetts Medical School, Worcester, MA, USA
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135
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Eichholz K, Bru T, Tran TTP, Fernandes P, Welles H, Mennechet FJD, Manel N, Alves P, Perreau M, Kremer EJ. Immune-Complexed Adenovirus Induce AIM2-Mediated Pyroptosis in Human Dendritic Cells. PLoS Pathog 2016; 12:e1005871. [PMID: 27636895 PMCID: PMC5026364 DOI: 10.1371/journal.ppat.1005871] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Accepted: 08/15/2016] [Indexed: 02/07/2023] Open
Abstract
Human adenoviruses (HAdVs) are nonenveloped proteinaceous particles containing a linear double-stranded DNA genome. HAdVs cause a spectrum of pathologies in all populations regardless of health standards. Following repeat exposure to multiple HAdV types, we develop robust and long-lived humoral and cellular immune responses that provide life-long protection from de novo infections and persistent HAdV. How HAdVs, anti-HAdV antibodies and antigen presenting cells (APCs) interact to influence infection is still incompletely understood. In our study, we used physical, pharmacological, biochemical, fluorescence and electron microscopy, molecular and cell biology approaches to dissect the impact of immune-complexed HAdV (IC-HAdV) on human monocyte-derived dendritic cells (MoDCs). We show that IC-HAdV generate stabilized complexes of ~200 nm that are efficiently internalized by, and aggregate in, MoDCs. By comparing IC-HAdV, IC-empty capsid, IC-Ad2ts1 (a HAdV-C2 impaired in endosomal escape due to a mutation that impacts protease encapsidation) and IC-AdL40Q (a HAdV-C5 impaired in endosomal escape due to a mutation in protein VI), we demonstrate that protein VI-dependent endosomal escape is required for the HAdV genome to engage the DNA pattern recognition receptor AIM2 (absent in melanoma 2). AIM2 engagement induces pyroptotic MoDC death via ASC (apoptosis-associated speck protein containing a caspase activation/recruitment domain) aggregation, inflammasome formation, caspase 1 activation, and IL-1β and gasdermin D (GSDMD) cleavage. Our study provides mechanistic insight into how humoral immunity initiates an innate immune response to HAdV-C5 in human professional APCs.
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Affiliation(s)
- Karsten Eichholz
- Institut de Génétique Moléculaire de Montpellier, CNRS 5535, Montpellier, France
- Université de Montpellier, Montpellier, France
| | - Thierry Bru
- Institut de Génétique Moléculaire de Montpellier, CNRS 5535, Montpellier, France
- Université de Montpellier, Montpellier, France
| | - Thi Thu Phuong Tran
- Institut de Génétique Moléculaire de Montpellier, CNRS 5535, Montpellier, France
- Université de Montpellier, Montpellier, France
| | - Paulo Fernandes
- iBET- Instituto de Biologia Experimental e Tecnológica, Oeiras, Portugal
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Hugh Welles
- Division of Immunology and Allergy, University of Lausanne, Lausanne, Switzerland
| | - Franck J. D. Mennechet
- Institut de Génétique Moléculaire de Montpellier, CNRS 5535, Montpellier, France
- Université de Montpellier, Montpellier, France
| | | | - Paula Alves
- iBET- Instituto de Biologia Experimental e Tecnológica, Oeiras, Portugal
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Matthieu Perreau
- Division of Immunology and Allergy, University of Lausanne, Lausanne, Switzerland
| | - Eric J. Kremer
- Institut de Génétique Moléculaire de Montpellier, CNRS 5535, Montpellier, France
- Université de Montpellier, Montpellier, France
- * E-mail:
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136
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Sinha SS, Cameron J, Brooks JC, Leifer CA. Complex Negative Regulation of TLR9 by Multiple Proteolytic Cleavage Events. THE JOURNAL OF IMMUNOLOGY 2016; 197:1343-52. [PMID: 27421483 DOI: 10.4049/jimmunol.1502357] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Accepted: 06/14/2016] [Indexed: 11/19/2022]
Abstract
TLR9 is an innate immune receptor important for recognizing DNA of host and foreign origin. A mechanism proposed to prevent excessive response to host DNA is the requirement for proteolytic cleavage of TLR9 in endosomes to generate a mature form of the receptor (TLR9(471-1032)). We previously described another cleavage event in the juxtamembrane region of the ectodomain that generated a dominant-negative form of TLR9. Thus, there are at least two independent cleavage events that regulate TLR9. In this study, we investigated whether an N-terminal fragment of TLR9 could be responsible for regulation of the mature or negative-regulatory form. We show that TLR9(471-1032), corresponding to the proteolytically cleaved form, does not function on its own. Furthermore, activity is not rescued by coexpression of the N-terminal fragment (TLR9(1-440)), inclusion of the hinge region (TLR9(441-1032)), or overexpression of UNC93B1, the last of which is critical for trafficking and cleavage of TLR9. TLR9(1-440) coimmunoprecipitates with full-length TLR9 and TLR9(471-1032) but does not rescue the native glycosylation pattern; thus, inappropriate trafficking likely explains why TLR9(471-1032) is nonfunctional. Lastly, we show that TLR9(471-1032) is also a dominant-negative regulator of TLR9 signaling. Together, these data provide a new perspective on the complexity of TLR9 regulation by proteolytic cleavage and offer potential ways to inhibit activity through this receptor, which may dampen autoimmune inflammation.
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Affiliation(s)
- Siddhartha S Sinha
- Department of Microbiology and Immunology, Cornell University, Ithaca, NY 14853; and
| | - Jody Cameron
- Department of Microbiology and Immunology, Cornell University, Ithaca, NY 14853; and
| | - James C Brooks
- Department of Microbiology and Immunology, Cornell University, Ithaca, NY 14853; and Glycobia Inc., Ithaca, NY 14853
| | - Cynthia A Leifer
- Department of Microbiology and Immunology, Cornell University, Ithaca, NY 14853; and
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137
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Prandini A, Salvi V, Colombo F, Moratto D, Lorenzi L, Vermi W, De Francesco MA, Notarangelo LD, Porta F, Plebani A, Facchetti F, Sozzani S, Badolato R. Impairment of dendritic cell functions in patients with adaptor protein-3 complex deficiency. Blood 2016; 127:3382-6. [PMID: 27207797 DOI: 10.1182/blood-2015-06-650689] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Accepted: 05/09/2016] [Indexed: 01/02/2023] Open
Abstract
Hermansky-Pudlak syndrome type 2 (HPS2) is a primary immunodeficiency due to adaptor protein-3 (AP-3) complex deficiency. HPS2 patients present neutropenia, partial albinism, and impaired lysosomal vesicles formation in hematopoietic cells. Given the role of dendritic cells (DCs) in the immune response, we studied monocyte-derived DCs (moDCs) and plasmacytoid DCs (pDCs) in two HPS2 siblings. Mature HPS2 moDCs showed impaired expression of CD83 and DC-lysosome-associated membrane protein (LAMP), low levels of MIP1-β/CCL4, MIG/CXCL9, and severe defect of interleukin-12 (IL-12) secretion. DCs in lymph-node biopsies from the same patients showed a diffuse cytoplasm reactivity in a large fraction of DC-LAMP(+) cells, instead of the classical dot-like stain. In addition, analysis of pDC-related functions of blood-circulating mononuclear cells revealed reduced interferon-α secretion in response to herpes simplex virus-1 (HSV-1), whereas granzyme-B induction upon IL-3/IL-10 stimulation was normal. Finally, T-cell costimulatory activity, as measured by mixed lymphocyte reaction assay, was lower in patients, suggesting that function and maturation of DCs is abnormal in patients with HPS2.
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Affiliation(s)
- Alberto Prandini
- Department of Clinical and Experimental Sciences, Institute of Molecular Medicine "Angelo Nocivelli,"
| | - Valentina Salvi
- Department of Molecular and Translational Medicine, Section of Experimental Oncology and Immunology
| | - Francesca Colombo
- Department of Clinical and Experimental Sciences, Institute of Molecular Medicine "Angelo Nocivelli,"
| | - Daniele Moratto
- Department of Clinical and Experimental Sciences, Institute of Molecular Medicine "Angelo Nocivelli,"
| | - Luisa Lorenzi
- Department of Molecular and Translational Medicine, Section of Experimental Oncology and Immunology, Section of Pathology, and
| | - William Vermi
- Department of Molecular and Translational Medicine, Section of Experimental Oncology and Immunology, Section of Pathology, and
| | | | - Lucia Dora Notarangelo
- U.O. Oncoematologia Pediatrica e Trapianto di Midollo Osseo c/o Spedali Civili, Brescia, Italy; and
| | - Fulvio Porta
- U.O. Oncoematologia Pediatrica e Trapianto di Midollo Osseo c/o Spedali Civili, Brescia, Italy; and
| | - Alessandro Plebani
- Department of Clinical and Experimental Sciences, Institute of Molecular Medicine "Angelo Nocivelli,"
| | - Fabio Facchetti
- Department of Molecular and Translational Medicine, Section of Experimental Oncology and Immunology
| | - Silvano Sozzani
- Department of Molecular and Translational Medicine, Section of Experimental Oncology and Immunology, Humanitas Clinical and Research Center, Rozzano, Italy
| | - Raffaele Badolato
- Department of Clinical and Experimental Sciences, Institute of Molecular Medicine "Angelo Nocivelli,"
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138
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Leifer CA, Medvedev AE. Molecular mechanisms of regulation of Toll-like receptor signaling. J Leukoc Biol 2016; 100:927-941. [PMID: 27343013 DOI: 10.1189/jlb.2mr0316-117rr] [Citation(s) in RCA: 184] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Accepted: 06/01/2016] [Indexed: 01/22/2023] Open
Abstract
TLRs play a critical role in the detection of microbes and endogenous "alarmins" to initiate host defense, yet they can also contribute to the development and progression of inflammatory and autoimmune diseases. To avoid pathogenic inflammation, TLR signaling is subject to multilayer regulatory control mechanisms, including cooperation with coreceptors, post-translational modifications, cleavage, cellular trafficking, and interactions with negative regulators. Nucleic acid-sensing TLRs are particularly interesting in this regard, as they can both recognize host-derived structures and require internalization of their ligand as a result of intracellular sequestration of the nucleic acid-sensing TLRs. This review summarizes the regulatory mechanisms of TLRs, including regulation of their access to ligands, receptor folding, intracellular trafficking, and post-translational modifications, as well as how altered control mechanism could contribute to inflammatory and autoimmune disorders.
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Affiliation(s)
- Cynthia A Leifer
- Department of Microbiology and Immunology, Cornell University, Ithaca, New York, USA; and
| | - Andrei E Medvedev
- Department of Immunology, University of Connecticut Heath Center, Farmington, Connecticut, USA
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139
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Distinct NF-κB and MAPK Activation Thresholds Uncouple Steady-State Microbe Sensing from Anti-pathogen Inflammatory Responses. Cell Syst 2016; 2:378-90. [PMID: 27237739 DOI: 10.1016/j.cels.2016.04.016] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Revised: 03/29/2016] [Accepted: 04/22/2016] [Indexed: 12/30/2022]
Abstract
The innate immune system distinguishes low-level homeostatic microbial stimuli from those of invasive pathogens, yet we lack understanding of how qualitatively similar microbial products yield context-specific macrophage functional responses. Using quantitative approaches, we found that NF-κB and MAPK signaling was activated at different concentrations of a stimulatory TLR4 ligand in both mouse and human macrophages. Above a threshold of ligand, MAPK were activated in a switch-like manner, facilitating production of inflammatory mediators. At ligand concentrations below this threshold, NF-κB signaling occurred, promoting expression of a restricted set of genes and macrophage priming. Among TLR-induced genes, we observed an inverse correlation between MAPK dependence and ligand sensitivity, highlighting the role of this signaling dichotomy in partitioning innate responses downstream of a single receptor. Our study reveals an evolutionarily conserved innate immune response system in which danger discrimination is enforced by distinct thresholds for NF-κB and MAPK activation, which provide sequential barriers to inflammatory mediator production.
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140
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Access of protective antiviral antibody to neuronal tissues requires CD4 T-cell help. Nature 2016; 533:552-6. [PMID: 27225131 PMCID: PMC4883597 DOI: 10.1038/nature17979] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2015] [Accepted: 04/05/2016] [Indexed: 12/24/2022]
Abstract
Circulating antibodies can access most tissues to mediate surveillance and elimination of invading pathogens. Immunopriviledged tissues such as the brain and the peripheral nervous system, are shielded from plasma proteins, by the blood-brain barrier1 and blood nerve barrier2, respectively. Yet, circulating antibodies must somehow gain access to these tissues in order to mediate their antimicrobial functions. Here, we examine the mechanism by which antibodies gain access to neuronal tissues to control infection. Using mouse model of genital herpes infection, we demonstrate that both antibodies and CD4 T cells are required to protect the host following immunization at a distal site. We show that memory CD4 T cells migrate to the dorsal root ganglia (DRG) and spinal cord in response to HSV-2 infection. Once inside these neuronal tissues, CD4 T cells secrete interferon (IFN)-γ and mediate local increase in vascular permeability, enabling antibody access for viral control. A similar requirement for CD4 T cells for antibody access to the brain was observed following intranasal challenge with vesicular stomatitis virus. Our results reveal a previously unappreciated role of CD4 help in mobilizing antibodies to the peripheral sites of infection where they help to limit viral spread.
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141
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Comparison of the Proinflammatory and Procoagulant Properties of Nuclear, Mitochondrial, and Bacterial DNA. Shock 2016; 44:265-71. [PMID: 25944792 DOI: 10.1097/shk.0000000000000397] [Citation(s) in RCA: 88] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
PURPOSE Cell-free DNA (CFDNA) is elevated in sepsis and correlates with mortality. This DNA may come from nuclear, mitochondrial, or bacterial sources. Cell-free DNA from all three sources may play a pathogenic role in sepsis via activation of coagulation through the contact pathway, whereas CpG motifs on bacterial and mitochondrial DNA may additionally stimulate inflammatory responses via Toll-like receptor 9. This study elucidates the relative effects of nuclear, mitochondrial, and bacterial DNA on inflammatory and procoagulant pathways with relevance to sepsis. METHODS DNA was extracted from plasma of septic patients and control subjects, and nuclear and mitochondrial CFDNA concentrations were measured by quantitative polymerase chain reaction. Viability of primary cultured human neutrophils was measured by flow cytometry for phosphatidyl serine exposure and cell permeability to propidium iodide. Continuous thrombin generation was measured with a fluorogenic substrate (Technothrombin, Vienna, Austria). Interleukin 6 secretion was measured by enzyme-linked immunosorbent assay. Platelet activation was measured by flow cytometry for P-selectin and activated αIIbβ3. RESULTS Mitochondrial DNA and nuclear DNA were elevated in plasma from septic patients compared with control subjects. Both mitochondrial and bacterial DNA prolonged neutrophil viability. Bacterial DNA increased neutrophil interleukin 6 secretion, but mitochondrial and nuclear DNA did not. Nuclear, mitochondrial, and bacterial DNA increased thrombin generation in platelet-poor plasma to a similar degree in a FXI- and FXII-dependent manner, indicating dependence on the intrinsic pathway of coagulation. Independently of coagulation, DNA from all three sources was capable of causing activation of platelet integrin αIIbβ3. CONCLUSIONS Cell-free DNA from nuclear, mitochondrial, and bacterial sources have varying proinflammatory effects, although all three have similar procoagulant and platelet-stimulating potential. The pathophysiological effects of CFDNA in sepsis may vary with the source of DNA.
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O’Brien M, Manches O, Wilen C, Gopal R, Huq R, Wu V, Sunseri N, Bhardwaj N. CD4 Receptor is a Key Determinant of Divergent HIV-1 Sensing by Plasmacytoid Dendritic Cells. PLoS Pathog 2016; 12:e1005553. [PMID: 27082754 PMCID: PMC4833349 DOI: 10.1371/journal.ppat.1005553] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Accepted: 03/14/2016] [Indexed: 11/26/2022] Open
Abstract
Plasmacytoid dendritic cells (pDC) are innate immune cells that sense viral nucleic acids through endosomal Toll-like receptor (TLR) 7/9 to produce type I interferon (IFN) and to differentiate into potent antigen presenting cells (APC). Engagement of TLR7/9 in early endosomes appears to trigger the IRF7 pathway for IFN production whereas engagement in lysosomes seems to trigger the NF-κB pathway for maturation into APC. We showed previously that HIV-1 (HIV) localizes predominantly to early endosomes, not lysosomes, and mainly stimulate IRF7 rather than NF-κB signaling pathways in pDC. This divergent signaling may contribute to disease progression through production of pro-apoptotic and pro-inflammatory IFN and inadequate maturation of pDCs. We now demonstrate that HIV virions may be re-directed to lysosomes for NF-κB signaling by either pseudotyping HIV with influenza hemagglutinin envelope or modification of CD4 mediated-intracellular trafficking. These data suggest that HIV envelope-CD4 receptor interactions drive pDC activation toward an immature IFN producing phenotype rather than differentiation into a mature dendritic cell phenotype. Plasmacytoid dendritic cells (pDC) are innate immune cells that are specialized to produce type I interferon (IFN) and to activate adaptive immune responses. Although IFN is an anti-viral cytokine, it may contribute more to pathogenesis than to protection during chronic viral infections, including chronic HIV infection. pDC sense HIV to produce abundant IFN but minimal NF- κB–dependent production of TNFα and minimal up-regulation of co-stimulatory molecules, suggesting that HIV promotes pDC to become interferon producing cells (IPC) rather than antigen presenting cells (APC). Here, we use florescent HIV virions pseudotyped with influenza hemagglutinin (HA) envelope and a cell system expressing CD4 molecules with modified intracellular trafficking. We found that HIV virions pseudotyped with HA stimulate pDC to mature, similar to influenza-stimulated pDC, and traffic intracellularly similarly to influenza. We also find that CD4-mediated intracellular trafficking guides HIV trafficking and downstream signaling. Our study presents new and important findings which demonstrate that divergent HIV sensing by pDC to produce IFN, rather than to become mature antigen presenting cells, is mediated specifically by CD4-HIV envelope interactions.
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Affiliation(s)
- Meagan O’Brien
- Division of Infectious Diseases, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, United States of America
- * E-mail: Meagan.O’ (MO); (OM)
| | - Olivier Manches
- Division of Hematology and Oncology, Hess Center for Science and Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, United States of America
- * E-mail: Meagan.O’ (MO); (OM)
| | - Craig Wilen
- Department of Pathology & Immunology, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Ramya Gopal
- Division of Hematology and Oncology, Hess Center for Science and Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, United States of America
| | - Rumana Huq
- Microscopy Shared Resource Facility, Icahn School of Medicine at Mount Sinai, New York, New York, United States of America
| | - Vernon Wu
- Division of Hematology and Oncology, Hess Center for Science and Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, United States of America
| | - Nicole Sunseri
- Department of Pediatrics, the University of Chicago, Chicago, Illinois, United States of America
| | - Nina Bhardwaj
- Division of Hematology and Oncology, Hess Center for Science and Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, United States of America
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Genome Wide Host Gene Expression Analysis in Chicken Lungs Infected with Avian Influenza Viruses. PLoS One 2016; 11:e0153671. [PMID: 27071061 PMCID: PMC4829244 DOI: 10.1371/journal.pone.0153671] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Accepted: 04/01/2016] [Indexed: 12/24/2022] Open
Abstract
The molecular pathogenesis of avian influenza infection varies greatly with individual bird species and virus strain. The molecular pathogenesis of the highly pathogenic avian influenza virus (HPAIV) or the low pathogenic avian influenza virus (LPAIV) infection in avian species remains poorly understood. Thus, global immune response of chickens infected with HPAI H5N1 (A/duck/India/02CA10/2011) and LPAI H9N2 (A/duck/India/249800/2010) viruses was studied using microarray to identify crucial host genetic components responsive to these infection. HPAI H5N1 virus induced excessive expression of type I IFNs (IFNA and IFNG), cytokines (IL1B, IL18, IL22, IL13, and IL12B), chemokines (CCL4, CCL19, CCL10, and CX3CL1) and IFN stimulated genes (OASL, MX1, RSAD2, IFITM5, IFIT5, GBP 1, and EIF2AK) in lung tissues. This dysregulation of host innate immune genes may be the critical determinant of the severity and the outcome of the influenza infection in chickens. In contrast, the expression levels of most of these genes was not induced in the lungs of LPAI H9N2 virus infected chickens. This study indicated the relationship between host immune genes and their roles in pathogenesis of HPAIV infection in chickens.
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The RNA- and TRIM25-Binding Domains of Influenza Virus NS1 Protein Are Essential for Suppression of NLRP3 Inflammasome-Mediated Interleukin-1β Secretion. J Virol 2016; 90:4105-4114. [PMID: 26865721 DOI: 10.1128/jvi.00120-16] [Citation(s) in RCA: 76] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Accepted: 02/02/2016] [Indexed: 12/25/2022] Open
Abstract
UNLABELLED Inflammasomes are cytosolic multimolecular protein complexes that stimulate the activation of caspase-1 and the release of mature forms of interleukin-1β (IL-1β) and IL-18. We previously demonstrated that the influenza A virus M2 protein stimulates IL-1β secretion following activation of the nucleotide-binding oligomerization domain (NOD)-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome. The nonstructural protein 1 (NS1) of influenza virus inhibits caspase-1 activation and IL-1β secretion. However, the precise mechanism by which NS1 inhibits IL-1β secretion remains unknown. Here, we showed that J774A.1 macrophages stably expressing the NS1 protein inhibited IL-1β secretion after infection with recombinant influenza virus lacking the NS1 gene. Coimmunoprecipitation assay revealed that the NS1 protein interacts with NLRP3. Importantly, the NS1 protein inhibited the NLRP3/ASC-induced single-speck formation required for full activation of inflammasomes. The NS1 protein of other influenza virus strains, including a recent pandemic strain, also inhibited inflammasome-mediated IL-1β secretion. The NS1 RNA-binding domain (basic residues 38 and 41) and TRIM25-binding domain (acidic residues 96 and 97) were required for suppression of NLRP3 inflammasome-mediated IL-1β secretion. These results shed light on a mechanism by which the NS1 protein of influenza virus suppresses NLRP3 inflammasome-mediated IL-1β secretion. IMPORTANCE Innate immune sensing of influenza virus via pattern recognition receptors not only plays a key role in generating type I interferons but also triggers inflammatory responses. We previously demonstrated that the influenza A virus M2 protein activates the NLRP3 inflammasome, leading to the secretion of interleukin-1β (IL-1β) and IL-18 following the activation of caspase-1. Although the nonstructural protein 1 (NS1) of influenza virus inhibits IL-1β secretion, the precise mechanism by which it achieves this remains to be defined. Here, we demonstrate that the NS1 protein interacts with NLRP3 to suppress NLRP3 inflammasome activation. J774A.1 macrophages stably expressing the NS1 protein suppressed NLRP3-mediated IL-1β secretion. The NS1 RNA-binding domain (basic residues 38 and 41) and TRIM25-binding domain (acidic residues 96 and 97) are important for suppression of NLRP3 inflammasome-mediated IL-1β secretion. These results will facilitate the development of new anti-inflammatory drugs.
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αv Integrins combine with LC3 and atg5 to regulate Toll-like receptor signalling in B cells. Nat Commun 2016; 7:10917. [PMID: 26965188 PMCID: PMC4792966 DOI: 10.1038/ncomms10917] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Accepted: 02/01/2016] [Indexed: 12/18/2022] Open
Abstract
Integrin signalling triggers cytoskeletal rearrangements, including endocytosis and exocytosis of integrins and other membrane proteins. In addition to recycling integrins, this trafficking can also regulate intracellular signalling pathways. Here we describe a role for αv integrins in regulating Toll-like receptor (TLR) signalling by modulating intracellular trafficking. We show that deletion of αv or β3 causes increased B-cell responses to TLR stimulation in vitro, and αv-conditional knockout mice have elevated antibody responses to TLR-ligand-associated antigens. αv regulates TLR signalling by promoting recruitment of the autophagy component LC3 (microtubule-associated proteins 1 light chain 3) to TLR-containing endosomes, which is essential for progression from NF-κB to IRF signalling, and ultimately for traffic to lysosomes where signalling is terminated. Disruption of LC3 recruitment leads to prolonged NF-κB signalling and increased B-cell proliferation and antibody production. This work identifies a previously unrecognized role for αv and the autophagy components LC3 and atg5 in regulating TLR signalling and B-cell immunity. Integrins can regulate antigen-specific and innate immune receptor signalling, thereby affecting immune cell function. Here the authors show that avß3 integrin controls Toll-like receptor (TLR) signalling by regulating its trafficking to limit TLR-mediated B-cell proliferation and antibody production.
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146
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Hasan M, Gruber E, Cameron J, Leifer CA. TLR9 stability and signaling are regulated by phosphorylation and cell stress. J Leukoc Biol 2016; 100:525-33. [PMID: 26957214 DOI: 10.1189/jlb.2a0815-337r] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Accepted: 02/02/2016] [Indexed: 12/27/2022] Open
Abstract
Innate sensing of pathogens elicits protective immune responses through pattern recognition receptors, including Toll-like receptors. Although signaling by Toll-like receptors is regulated at multiple steps, including localization, trafficking, proteolytic cleavage, and phosphorylation, the significance of post-translational modifications and cellular stress response on Toll-like receptor stability and signaling is still largely unknown. In the present study, we investigated the role of cytoplasmic tyrosine motifs in Toll-like receptor-9 stability, proteolytic cleavage, and signaling. We demonstrated that tyrosine phosphorylation is essential for mouse Toll-like receptor-9 protein stability and signaling. Upon inhibition of tyrosine kinases with piceatannol, Toll-like receptor-9 tyrosine phosphorylation induced by CpG deoxyribonucleic acid was inhibited, which correlated with decreased signaling. Furthermore, inhibition of Src kinases with 1-tert-Butyl-3-(4-chlorophenyl)-1H-pyrazolo[3,4-d]pyrimidin-4-amine also inhibited response to CpG deoxyribonucleic acid. Toll-like receptor-9 protein stability was also sensitive to autophagy, the cellular stress response pathway, and infection by a deoxyribonucleic acid virus. Whereas autophagy induced by rapamycin or low serum levels caused a preferential loss of the mature p80 proteolytic cleavage product, infection with herpes simplex virus-1 and induction of cell stress with tunicamycin caused preferential loss of full-length Toll-like receptor-9, which is localized to the endoplasmic reticulum. Our data reveal new information about the stability and signaling of Toll-like receptor-9 and suggest that immune evasion mechanisms may involve targeted loss of innate sensing receptors.
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Affiliation(s)
- Maroof Hasan
- Department of Microbiology and Immunology, Cornell University, Ithaca, New York, USA
| | - Erika Gruber
- Department of Microbiology and Immunology, Cornell University, Ithaca, New York, USA
| | - Jody Cameron
- Department of Microbiology and Immunology, Cornell University, Ithaca, New York, USA
| | - Cynthia A Leifer
- Department of Microbiology and Immunology, Cornell University, Ithaca, New York, USA
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Ortega MS, Denicol AC, Cole JB, Null DJ, Hansen PJ. Use of single nucleotide polymorphisms in candidate genes associated with daughter pregnancy rate for prediction of genetic merit for reproduction in Holstein cows. Anim Genet 2016; 47:288-97. [DOI: 10.1111/age.12420] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/24/2015] [Indexed: 12/20/2022]
Affiliation(s)
- M. S. Ortega
- Department of Animal Sciences; D.H. Barron Reproductive and Perinatal Biology Research Program and Genetics Institute; University of Florida; Gainesville FL USA
| | - A. C. Denicol
- Department of Animal Sciences; D.H. Barron Reproductive and Perinatal Biology Research Program and Genetics Institute; University of Florida; Gainesville FL USA
| | - J. B. Cole
- Animal Genomics and Improvement Laboratory; Agricultural Research Service; United States Department of Agriculture; Beltsville MD USA
| | - D. J. Null
- Animal Genomics and Improvement Laboratory; Agricultural Research Service; United States Department of Agriculture; Beltsville MD USA
| | - P. J. Hansen
- Department of Animal Sciences; D.H. Barron Reproductive and Perinatal Biology Research Program and Genetics Institute; University of Florida; Gainesville FL USA
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Differences in codon bias and GC content contribute to the balanced expression of TLR7 and TLR9. Proc Natl Acad Sci U S A 2016; 113:E1362-71. [PMID: 26903634 DOI: 10.1073/pnas.1518976113] [Citation(s) in RCA: 77] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The innate immune system detects diverse microbial species with a limited repertoire of immune receptors that recognize nucleic acids. The cost of this immune surveillance strategy is the potential for inappropriate recognition of self-derived nucleic acids and subsequent autoimmune disease. The relative expression of two closely related receptors, Toll-like receptor (TLR) 7 and TLR9, is balanced to allow recognition of microbial nucleic acids while limiting recognition of self-derived nucleic acids. Situations that tilt this balance toward TLR7 promote inappropriate responses, including autoimmunity; therefore, tight control of expression is critical for proper homeostasis. Here we report that differences in codon bias limit TLR7 expression relative to TLR9. Codon optimization of Tlr7 increases protein levels as well as responses to ligands, but, unexpectedly, these changes only modestly affect translation. Instead, we find that much of the benefit attributed to codon optimization is actually the result of enhanced transcription. Our findings, together with other recent examples, challenge the dogma that codon optimization primarily increases translation. We propose that suboptimal codon bias, which correlates with low guanine-cytosine (GC) content, limits transcription of certain genes. This mechanism may establish low levels of proteins whose overexpression leads to particularly deleterious effects, such as TLR7.
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149
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Biggadike K, Ahmed M, Ball DI, Coe DM, Dalmas Wilk DA, Edwards CD, Gibbon BH, Hardy CJ, Hermitage SA, Hessey JO, Hillegas AE, Hughes SC, Lazarides L, Lewell XQ, Lucas A, Mallett DN, Price MA, Priest FM, Quint DJ, Shah P, Sitaram A, Smith SA, Stocker R, Trivedi NA, Tsitoura DC, Weller V. Discovery of 6-Amino-2-{[(1S)-1-methylbutyl]oxy}-9-[5-(1-piperidinyl)pentyl]-7,9-dihydro-8H-purin-8-one (GSK2245035), a Highly Potent and Selective Intranasal Toll-Like Receptor 7 Agonist for the Treatment of Asthma. J Med Chem 2016; 59:1711-26. [PMID: 26861551 DOI: 10.1021/acs.jmedchem.5b01647] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Induction of IFNα in the upper airways via activation of TLR7 represents a novel immunomodulatory approach to the treatment of allergic asthma. Exploration of 8-oxoadenine derivatives bearing saturated oxygen or nitrogen heterocycles in the N-9 substituent has revealed a remarkable selective enhancement in IFNα inducing potency in the nitrogen series. Further potency enhancement was achieved with the novel (S)-pentyloxy substitution at C-2 leading to the selection of GSK2245035 (32) as an intranasal development candidate. In human cell cultures, compound 32 resulted in suppression of Th2 cytokine responses to allergens, while in vivo intranasal administration at very low doses led to local upregulation of TLR7-mediated cytokines (IP-10). Target engagement was confirmed in humans following single intranasal doses of 32 of ≥20 ng, and reproducible pharmacological response was demonstrated following repeat intranasal dosing at weekly intervals.
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Affiliation(s)
- Keith Biggadike
- GlaxoSmithKline R&D, Medicines Research Centre , Gunnels Wood Road, Stevenage, Hertfordshire SG1 2NY, U.K
| | - Mahbub Ahmed
- GlaxoSmithKline R&D, Medicines Research Centre , Gunnels Wood Road, Stevenage, Hertfordshire SG1 2NY, U.K
| | - Doug I Ball
- GlaxoSmithKline R&D, Medicines Research Centre , Gunnels Wood Road, Stevenage, Hertfordshire SG1 2NY, U.K
| | - Diane M Coe
- GlaxoSmithKline R&D, Medicines Research Centre , Gunnels Wood Road, Stevenage, Hertfordshire SG1 2NY, U.K
| | - Deidre A Dalmas Wilk
- GlaxoSmithKline R&D, UpperMerion , 709 Swedeland Road, King of Prussia, Pennsylvania 19406, United States
| | - Chris D Edwards
- GlaxoSmithKline R&D, Medicines Research Centre , Gunnels Wood Road, Stevenage, Hertfordshire SG1 2NY, U.K
| | - Bob H Gibbon
- GlaxoSmithKline R&D, David Jack Centre , Park Road, Ware, Hertfordshire SG12 ODP, U.K
| | - Charlotte J Hardy
- GlaxoSmithKline R&D, Medicines Research Centre , Gunnels Wood Road, Stevenage, Hertfordshire SG1 2NY, U.K
| | - Stephen A Hermitage
- GlaxoSmithKline R&D, Medicines Research Centre , Gunnels Wood Road, Stevenage, Hertfordshire SG1 2NY, U.K
| | - Joanne O Hessey
- GlaxoSmithKline R&D, Medicines Research Centre , Gunnels Wood Road, Stevenage, Hertfordshire SG1 2NY, U.K
| | - Aimee E Hillegas
- GlaxoSmithKline R&D, UpperMerion , 709 Swedeland Road, King of Prussia, Pennsylvania 19406, United States
| | - Stephen C Hughes
- GlaxoSmithKline R&D, David Jack Centre , Park Road, Ware, Hertfordshire SG12 ODP, U.K
| | - Linos Lazarides
- GlaxoSmithKline R&D, Medicines Research Centre , Gunnels Wood Road, Stevenage, Hertfordshire SG1 2NY, U.K
| | - Xiao Q Lewell
- GlaxoSmithKline R&D, Medicines Research Centre , Gunnels Wood Road, Stevenage, Hertfordshire SG1 2NY, U.K
| | - Amanda Lucas
- GlaxoSmithKline R&D, Medicines Research Centre , Gunnels Wood Road, Stevenage, Hertfordshire SG1 2NY, U.K
| | - David N Mallett
- GlaxoSmithKline R&D, Medicines Research Centre , Gunnels Wood Road, Stevenage, Hertfordshire SG1 2NY, U.K
| | - Mark A Price
- GlaxoSmithKline R&D, David Jack Centre , Park Road, Ware, Hertfordshire SG12 ODP, U.K
| | - Fiona M Priest
- GlaxoSmithKline R&D, Medicines Research Centre , Gunnels Wood Road, Stevenage, Hertfordshire SG1 2NY, U.K
| | - Diana J Quint
- GlaxoSmithKline R&D, Medicines Research Centre , Gunnels Wood Road, Stevenage, Hertfordshire SG1 2NY, U.K
| | - Poonam Shah
- GlaxoSmithKline R&D, Medicines Research Centre , Gunnels Wood Road, Stevenage, Hertfordshire SG1 2NY, U.K
| | - Anesh Sitaram
- GlaxoSmithKline R&D, David Jack Centre , Park Road, Ware, Hertfordshire SG12 ODP, U.K
| | - Stephen A Smith
- GlaxoSmithKline R&D, Medicines Research Centre , Gunnels Wood Road, Stevenage, Hertfordshire SG1 2NY, U.K
| | - Richard Stocker
- GlaxoSmithKline R&D, Medicines Research Centre , Gunnels Wood Road, Stevenage, Hertfordshire SG1 2NY, U.K
| | - Naimisha A Trivedi
- GlaxoSmithKline R&D, Medicines Research Centre , Gunnels Wood Road, Stevenage, Hertfordshire SG1 2NY, U.K
| | - Daphne C Tsitoura
- GlaxoSmithKline R&D, Medicines Research Centre , Gunnels Wood Road, Stevenage, Hertfordshire SG1 2NY, U.K
| | - Victoria Weller
- GlaxoSmithKline R&D, Medicines Research Centre , Gunnels Wood Road, Stevenage, Hertfordshire SG1 2NY, U.K
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150
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Khan NS, Kasperkovitz PV, Timmons AK, Mansour MK, Tam JM, Seward MW, Reedy JL, Puranam S, Feliu M, Vyas JM. Dectin-1 Controls TLR9 Trafficking to Phagosomes Containing β-1,3 Glucan. THE JOURNAL OF IMMUNOLOGY 2016; 196:2249-61. [PMID: 26829985 DOI: 10.4049/jimmunol.1401545] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Accepted: 01/03/2016] [Indexed: 12/23/2022]
Abstract
Dectin-1 and TLR9 play distinct roles in the recognition and induction of innate immune responses to Aspergillus fumigatus and Candida albicans. Dectin-1 is a receptor for the major fungal cell wall carbohydrate β-1,3 glucan that induces inflammatory cytokines and controls phagosomal maturation through spleen tyrosine kinase activation. TLR9 is an endosomal TLR that also modulates the inflammatory cytokine response to fungal pathogens. In this study, we demonstrate that β-1,3 glucan beads are sufficient to induce dynamic redistribution and accumulation of cleaved TLR9 to phagosomes. Trafficking of TLR9 to A. fumigatus and C. albicans phagosomes requires Dectin-1 recognition. Inhibition of phagosomal acidification blocks TLR9 accumulation on phagosomes containing β-1,3 glucan beads. Dectin-1-mediated spleen tyrosine kinase activation is required for TLR9 trafficking to β-1,3 glucan-, A. fumigatus-, and C. albicans-containing phagosomes. In addition, Dectin-1 regulates TLR9-dependent gene expression. Collectively, our study demonstrates that recognition of β-1,3 glucan by Dectin-1 triggers TLR9 trafficking to β-1,3 glucan-containing phagosomes, which may be critical in coordinating innate antifungal defense.
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Affiliation(s)
- Nida S Khan
- Division of Infectious Diseases, Department of Medicine, Massachusetts General Hospital, Boston, MA 02114; Biomedical Engineering and Biotechnology, University of Massachusetts, Lowell, MA 01854
| | | | - Allison K Timmons
- Division of Infectious Diseases, Department of Medicine, Massachusetts General Hospital, Boston, MA 02114
| | - Michael K Mansour
- Division of Infectious Diseases, Department of Medicine, Massachusetts General Hospital, Boston, MA 02114; Department of Medicine, Harvard Medical School, Boston, MA 02115
| | - Jenny M Tam
- Division of Infectious Diseases, Department of Medicine, Massachusetts General Hospital, Boston, MA 02114
| | - Michael W Seward
- Division of Infectious Diseases, Department of Medicine, Massachusetts General Hospital, Boston, MA 02114
| | - Jennifer L Reedy
- Division of Infectious Diseases, Department of Medicine, Massachusetts General Hospital, Boston, MA 02114; Department of Medicine, Harvard Medical School, Boston, MA 02115
| | - Sravanthi Puranam
- Division of Infectious Diseases, Department of Medicine, Massachusetts General Hospital, Boston, MA 02114
| | - Marianela Feliu
- Division of Infectious Diseases, Department of Medicine, Massachusetts General Hospital, Boston, MA 02114; Nutrition and Metabolism, Boston University, Boston, MA 02118; and
| | - Jatin M Vyas
- Division of Infectious Diseases, Department of Medicine, Massachusetts General Hospital, Boston, MA 02114; Department of Medicine, Harvard Medical School, Boston, MA 02115; Program in Immunology, Harvard Medical School, Boston, MA 02115
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