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Liu D, He W, Yang LL. Revitalizing antitumor immunity: Leveraging nucleic acid sensors as therapeutic targets. Cancer Lett 2024; 588:216729. [PMID: 38387757 DOI: 10.1016/j.canlet.2024.216729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Revised: 01/30/2024] [Accepted: 02/12/2024] [Indexed: 02/24/2024]
Abstract
Nucleic acid sensors play a critical role in recognizing and responding to pathogenic nucleic acids as danger signals. Upon activation, these sensors initiate downstream signaling cascades that lead to the production and release of pro-inflammatory cytokines, chemokines, and type I interferons. These immune mediators orchestrate diverse effector responses, including the activation of immune cells and the modulation of the tumor microenvironment. However, careful consideration must be given to balancing the activation of nucleic acid sensors to avoid unwanted autoimmune or inflammatory responses. In this review, we provide an overview of nucleic acid sensors and their role in combating cancer through the perception of various aberrant nucleic acids and activation of the immune system. We discuss the connections between different programmed cell death modes and nucleic acid sensors. Finally, we outline the development of nucleic acid sensor agonists, highlighting how their potential as therapeutic targets opens up new avenues for cancer immunotherapy.
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Affiliation(s)
- Danfeng Liu
- Department of Stomatology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou 450052, PR China
| | - Wei He
- Department of Stomatology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou 450052, PR China.
| | - Lei-Lei Yang
- Department of Stomatology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou 450052, PR China.
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2
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Snoek L, Karampatsas K, Bijlsma MW, Henneke P, Jauneikaite E, Khan UB, Zadoks RN, Le Doare K. Meeting report: Towards better risk stratification, prevention and therapy of invasive GBS disease, ESPID research meeting May 2022. Vaccine 2023; 41:6137-6142. [PMID: 37699783 DOI: 10.1016/j.vaccine.2023.09.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 08/14/2023] [Accepted: 09/05/2023] [Indexed: 09/14/2023]
Abstract
The European Society of Pediatric Infectious Diseases (ESPID) hosted the third Group B Streptococcus (GBS) Research Session in Athens on 11th May 2022, providing researchers and clinicians from around the world an opportunity to share and discuss recent advances in GBS pathophysiology, molecular and genetic epidemiology and how these new insights can help in improving prevention and control of early- and late-onset GBS disease. The meeting provided a state-of-the-art overview of the existing GBS prevention strategies and their limitations, and an opportunity to share the latest research findings. The first presentation provided an overview of current GBS prevention and treatment strategies. In the second presentation, the genomic and antimicrobial resistance profiles of invasive and colonizing GBS strains were presented. The third presentation explained the association of intrapartum antibiotic prophylaxis (IAP) with the development of late-onset disease (LOD) and the interplay of host innate immunity and GBS. The fourth presentation evaluated the role of genomics in understanding horizontal GBS transmission. The fifth presentation focused on the zoonotic links for certain GBS lineages and the last presentation described the protective role of breastmilk. Talks were followed with interactive discussions and concluded with recommendations on what is needed to further GBS clinical research; these included: (i) the development of better risk stratification methods by combining GBS virulence factors, serological biomarkers and clinical risk factors; (ii) further studies on the interplay of perinatal antimicrobials, disturbances in the development of host immunity and late-onset GBS disease; (iii) routine submission of GBS isolates to reference laboratories to help in detecting potential clusters by using genomic sequencing; (iv) collaboration in animal and human GBS studies to detect and prevent the emergence of new pathogenic sequence types; and (v) harnessing the plethora of immune factors in the breastmilk to develop adjunct therapies.
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Affiliation(s)
- Linde Snoek
- Department of Neurology, Amsterdam University Medical Centre, University of Amsterdam, Amsterdam, Netherlands; Amsterdam Neuroscience, Neuroinfection and Inflammation, Amsterdam, Netherlands.
| | - Konstantinos Karampatsas
- Paediatric Infectious Diseases Research Group, Institute of Infection and Immunity, St. George's, University of London, London, United Kingdom
| | - Merijn W Bijlsma
- Amsterdam Neuroscience, Neuroinfection and Inflammation, Amsterdam, Netherlands; Department of Paediatrics, Amsterdam University Medical Centre, University of Amsterdam, Amsterdam, Netherlands
| | - Philipp Henneke
- Institute for Immunodeficiency, Center for Chronic Immunodeficiency (CCI), University Medical Center and Faculty of Medicine, Freiburg, Germany; Institute for Infection Prevention and Control, University Medical Center and Faculty of Medicine, Freiburg, Germany
| | - Elita Jauneikaite
- Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, London, United Kingdom; NIHR Health Protection Research Unit in Healthcare Associated Infections and Antimicrobial Resistance, Department of Infectious Disease, Imperial College London, Hammersmith Hospital, London, United Kingdom
| | - Uzma B Khan
- Division of Infection and Immunity, School of Medicine, Cardiff University, Cardiff, United Kingdom; Parasites and Microbes, Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, United Kingdom
| | - Ruth N Zadoks
- Sydney School of Veterinary Science, Faculty of Science, The University of Sydney, Sydney, Australia
| | - Kirsty Le Doare
- Paediatric Infectious Diseases Research Group, Institute of Infection and Immunity, St. George's, University of London, London, United Kingdom
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3
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Klammer MG, Dzaye O, Wallach T, Krüger C, Gaessler D, Buonfiglioli A, Derkow K, Kettenmann H, Brinkmann MM, Lehnardt S. UNC93B1 Is Widely Expressed in the Murine CNS and Is Required for Neuroinflammation and Neuronal Injury Induced by MicroRNA let-7b. Front Immunol 2021; 12:715774. [PMID: 34589086 PMCID: PMC8475950 DOI: 10.3389/fimmu.2021.715774] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Accepted: 08/19/2021] [Indexed: 12/12/2022] Open
Abstract
The chaperone protein Unc-93 homolog B1 (UNC93B1) regulates internalization, trafficking, and stabilization of nucleic acid-sensing Toll-like receptors (TLR) in peripheral immune cells. We sought to determine UNC93B1 expression and its functional relevance in inflammatory and injurious processes in the central nervous system (CNS). We found that UNC93B1 is expressed in various CNS cells including microglia, astrocytes, oligodendrocytes, and neurons, as assessed by PCR, immunocyto-/histochemistry, and flow cytometry. UNC93B1 expression in the murine brain increased during development. Exposure to the microRNA let-7b, a recently discovered endogenous TLR7 activator, but also to TLR3 and TLR4 agonists, led to increased UNC93B1 expression in microglia and neurons. Microglial activation by extracellular let-7b required functional UNC93B1, as assessed by TNF ELISA. Neuronal injury induced by extracellular let-7b was dependent on UNC93B1, as UNC93B1-deficient neurons were unaffected by the microRNA's neurotoxicity in vitro. Intrathecal application of let-7b triggered neurodegeneration in wild-type mice, whereas mice deficient for UNC93B1 were protected against injurious effects on neurons and axons. In summary, our data demonstrate broad UNC93B1 expression in the murine brain and establish this chaperone as a modulator of neuroinflammation and neuronal injury triggered by extracellular microRNA and subsequent induction of TLR signaling.
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Affiliation(s)
- Markus G Klammer
- Institute of Cell Biology and Neurobiology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.,Department of Neurology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Omar Dzaye
- Department of Radiology and Neuroradiology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Thomas Wallach
- Institute of Cell Biology and Neurobiology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Christina Krüger
- Institute of Cell Biology and Neurobiology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Dorothea Gaessler
- Institute of Cell Biology and Neurobiology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Alice Buonfiglioli
- Institute of Cell Biology and Neurobiology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Katja Derkow
- Institute of Cell Biology and Neurobiology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Helmut Kettenmann
- Cellular Neuroscience, Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Melanie M Brinkmann
- Viral Immune Modulation Research Group, Helmholtz Centre for Infection Research, Braunschweig, Germany.,Institute of Genetics, Technische Universität Braunschweig, Braunschweig, Germany
| | - Seija Lehnardt
- Institute of Cell Biology and Neurobiology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.,Department of Neurology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
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4
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Lentini G, Famà A, De Gaetano GV, Galbo R, Coppolino F, Venza M, Teti G, Beninati C. Role of Endosomal TLRs in Staphylococcus aureus Infection. THE JOURNAL OF IMMUNOLOGY 2021; 207:1448-1455. [PMID: 34362834 DOI: 10.4049/jimmunol.2100389] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2021] [Accepted: 07/06/2021] [Indexed: 02/04/2023]
Abstract
Identification of the receptors involved in innate immune recognition of Staphylococcus aureus, a major cause of morbidity and mortality in humans, is essential to develop alternative strategies to treat infections caused by antibiotic-resistant strains. In the current study, we examine the role of endosomal TLRs, which sense the presence of prokaryotic-type nucleic acids, in anti-staphylococcal host defenses using infection models involving genetically defective mice. Single deficiencies in TLR7, 9, or 13 resulted in mild or no decrease in host defenses. However, the simultaneous absence of TLR7, 9, and 13 resulted in markedly increased susceptibility to cutaneous and systemic S. aureus infection concomitantly with decreased production of proinflammatory chemokines and cytokines, neutrophil recruitment to infection sites, and reduced production of reactive oxygen species. This phenotype was significantly more severe than that of mice lacking TLR2, which senses the presence of staphylococcal lipoproteins. Notably, the combined absence of TLR7, 9, and 13 resulted in complete abrogation of IL-12 p70 and IFN-β responses to staphylococcal stimulation in macrophages. Taken together, our data highlight the presence of a highly integrated endosomal detection system, whereby TLR7, 9, and 13 cooperate in sensing the presence of staphylococcal nucleic acids. We demonstrate that the combined absence of these receptors cannot be compensated for by cell surface-associated TLRs, such as TLR2, or cytosolic receptors. These data may be useful to devise strategies aimed at stimulating innate immune receptors to treat S. aureus infections.
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Affiliation(s)
- Germana Lentini
- Department of Human Pathology, University of Messina, Messina, Italy
| | - Agata Famà
- Department of Human Pathology, University of Messina, Messina, Italy
| | | | - Roberta Galbo
- Department of Chemical, Biological and Pharmaceutical Sciences, University of Messina, Messina, Italy
| | | | - Mario Venza
- Department of Biomedical, Dental and Imaging Sciences, University of Messina, Messina, Italy; and
| | | | - Concetta Beninati
- Department of Human Pathology, University of Messina, Messina, Italy
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5
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Baasch S, Giansanti P, Kolter J, Riedl A, Forde AJ, Runge S, Zenke S, Elling R, Halenius A, Brabletz S, Hengel H, Kuster B, Brabletz T, Cicin-Sain L, Arens R, Vlachos A, Rohr JC, Stemmler MP, Kopf M, Ruzsics Z, Henneke P. Cytomegalovirus subverts macrophage identity. Cell 2021; 184:3774-3793.e25. [PMID: 34115982 DOI: 10.1016/j.cell.2021.05.009] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 02/26/2021] [Accepted: 05/07/2021] [Indexed: 12/12/2022]
Abstract
Cytomegaloviruses (CMVs) have co-evolved with their mammalian hosts for millions of years, leading to remarkable host specificity and high infection prevalence. Macrophages, which already populate barrier tissues in the embryo, are the predominant immune cells at potential CMV entry sites. Here we show that, upon CMV infection, macrophages undergo a morphological, immunophenotypic, and metabolic transformation process with features of stemness, altered migration, enhanced invasiveness, and provision of the cell cycle machinery for viral proliferation. This complex process depends on Wnt signaling and the transcription factor ZEB1. In pulmonary infection, mouse CMV primarily targets and reprograms alveolar macrophages, which alters lung physiology and facilitates primary CMV and secondary bacterial infection by attenuating the inflammatory response. Thus, CMV profoundly perturbs macrophage identity beyond established limits of plasticity and rewires specific differentiation processes, allowing viral spread and impairing innate tissue immunity.
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Affiliation(s)
- Sebastian Baasch
- Institute for Immunodeficiency, Center for Chronic Immunodeficiency (CCI), University Medical Center, Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany
| | - Piero Giansanti
- Chair of Proteomics and Bioanalytics, Technical University of Munich, 85354 Freising, Germany
| | - Julia Kolter
- Institute for Immunodeficiency, Center for Chronic Immunodeficiency (CCI), University Medical Center, Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany
| | - André Riedl
- Institute of Virology, University Medical Center, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany; Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany
| | - Aaron James Forde
- Institute for Immunodeficiency, Center for Chronic Immunodeficiency (CCI), University Medical Center, Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany; Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany
| | - Solveig Runge
- Institute for Immunodeficiency, Center for Chronic Immunodeficiency (CCI), University Medical Center, Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany; Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany
| | - Simon Zenke
- Institute for Immunodeficiency, Center for Chronic Immunodeficiency (CCI), University Medical Center, Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany; Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany
| | - Roland Elling
- Institute for Immunodeficiency, Center for Chronic Immunodeficiency (CCI), University Medical Center, Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany; Center for Pediatrics and Adolescent Medicine, University Medical Center, 79106 Freiburg, Germany
| | - Anne Halenius
- Institute of Virology, University Medical Center, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany
| | - Simone Brabletz
- Department of Experimental Medicine I, Nikolaus-Fiebiger Center for Molecular Medicine, Friedrich Alexander University of Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Hartmut Hengel
- Institute of Virology, University Medical Center, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany
| | - Bernhard Kuster
- Chair of Proteomics and Bioanalytics, Technical University of Munich, 85354 Freising, Germany; Bavarian Center for Biomolecular Mass Spectrometry (BayBioMS), Technical University Munich, 85354 Freising, Germany
| | - Thomas Brabletz
- Department of Experimental Medicine I, Nikolaus-Fiebiger Center for Molecular Medicine, Friedrich Alexander University of Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Luka Cicin-Sain
- Immune Aging and Chronic Infections Group, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany; Cluster of Excellence RESIST (EXC 2155), Hanover Medical School (MHH), 30625 Hanover, Germany
| | - Ramon Arens
- Department of Immunology, Leiden University Medical Center, 2333 ZA Leiden, the Netherlands
| | - Andreas Vlachos
- Department of Neuroanatomy, Institute of Anatomy and Cell Biology, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany; Center for Basics in Neuromodulation (NeuroModulBasics), Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany
| | - Jan Christopher Rohr
- Institute for Immunodeficiency, Center for Chronic Immunodeficiency (CCI), University Medical Center, Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany; Center for Pediatrics and Adolescent Medicine, University Medical Center, 79106 Freiburg, Germany
| | - Marc Philippe Stemmler
- Department of Experimental Medicine I, Nikolaus-Fiebiger Center for Molecular Medicine, Friedrich Alexander University of Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Manfred Kopf
- Institute of Molecular Health Sciences, ETH Zürich, 8093 Zürich, Switzerland
| | - Zsolt Ruzsics
- Institute of Virology, University Medical Center, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany
| | - Philipp Henneke
- Institute for Immunodeficiency, Center for Chronic Immunodeficiency (CCI), University Medical Center, Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany; Center for Pediatrics and Adolescent Medicine, University Medical Center, 79106 Freiburg, Germany.
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6
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Rodríguez-Gómez JA, Kavanagh E, Engskog-Vlachos P, Engskog MK, Herrera AJ, Espinosa-Oliva AM, Joseph B, Hajji N, Venero JL, Burguillos MA. Microglia: Agents of the CNS Pro-Inflammatory Response. Cells 2020; 9:E1717. [PMID: 32709045 PMCID: PMC7407646 DOI: 10.3390/cells9071717] [Citation(s) in RCA: 150] [Impact Index Per Article: 37.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2020] [Revised: 07/14/2020] [Accepted: 07/15/2020] [Indexed: 12/21/2022] Open
Abstract
The pro-inflammatory immune response driven by microglia is a key contributor to the pathogenesis of several neurodegenerative diseases. Though the research of microglia spans over a century, the last two decades have increased our understanding exponentially. Here, we discuss the phenotypic transformation from homeostatic microglia towards reactive microglia, initiated by specific ligand binding to pattern recognition receptors including toll-like receptor-4 (TLR4) or triggering receptors expressed on myeloid cells-2 (TREM2), as well as pro-inflammatory signaling pathways triggered such as the caspase-mediated immune response. Additionally, new research disciplines such as epigenetics and immunometabolism have provided us with a more holistic view of how changes in DNA methylation, microRNAs, and the metabolome may influence the pro-inflammatory response. This review aimed to discuss our current knowledge of pro-inflammatory microglia from different angles, including recent research highlights such as the role of exosomes in spreading neuroinflammation and emerging techniques in microglia research including positron emission tomography (PET) scanning and the use of human microglia generated from induced pluripotent stem cells (iPSCs). Finally, we also discuss current thoughts on the impact of pro-inflammatory microglia in neurodegenerative diseases.
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Affiliation(s)
- José A. Rodríguez-Gómez
- Institute of Biomedicine of Seville (IBIS)-Hospital Universitario Virgen del Rocío/CSIC/University of Seville, 41012 Seville, Spain; (J.A.R.-G.); (A.J.H.); (A.M.E.-O.); (J.L.V.)
- Department of Medical Physiology and Biophysics, Faculty of Medicine, University of Seville, 41009 Sevilla, Spain
| | - Edel Kavanagh
- Department of Biochemistry and Molecular Biology, Faculty of Pharmacy, University of Seville, 41012 Seville, Spain;
| | - Pinelopi Engskog-Vlachos
- Institute of Environmental Medicine, Toxicology Unit, Karolinska Institute, 17177 Stockholm, Sweden; (P.E.-V.); (B.J.)
| | - Mikael K.R. Engskog
- Department of Medicinal Chemistry, Analytical Pharmaceutical Chemistry, Uppsala University, 751 23 Uppsala, Sweden;
| | - Antonio J. Herrera
- Institute of Biomedicine of Seville (IBIS)-Hospital Universitario Virgen del Rocío/CSIC/University of Seville, 41012 Seville, Spain; (J.A.R.-G.); (A.J.H.); (A.M.E.-O.); (J.L.V.)
- Department of Biochemistry and Molecular Biology, Faculty of Pharmacy, University of Seville, 41012 Seville, Spain;
| | - Ana M. Espinosa-Oliva
- Institute of Biomedicine of Seville (IBIS)-Hospital Universitario Virgen del Rocío/CSIC/University of Seville, 41012 Seville, Spain; (J.A.R.-G.); (A.J.H.); (A.M.E.-O.); (J.L.V.)
- Department of Biochemistry and Molecular Biology, Faculty of Pharmacy, University of Seville, 41012 Seville, Spain;
| | - Bertrand Joseph
- Institute of Environmental Medicine, Toxicology Unit, Karolinska Institute, 17177 Stockholm, Sweden; (P.E.-V.); (B.J.)
| | - Nabil Hajji
- Division of Brain Sciences, The John Fulcher Molecular Neuro-Oncology Laboratory, Imperial College London, London W12 ONN, UK;
| | - José L. Venero
- Institute of Biomedicine of Seville (IBIS)-Hospital Universitario Virgen del Rocío/CSIC/University of Seville, 41012 Seville, Spain; (J.A.R.-G.); (A.J.H.); (A.M.E.-O.); (J.L.V.)
- Department of Biochemistry and Molecular Biology, Faculty of Pharmacy, University of Seville, 41012 Seville, Spain;
| | - Miguel A. Burguillos
- Institute of Biomedicine of Seville (IBIS)-Hospital Universitario Virgen del Rocío/CSIC/University of Seville, 41012 Seville, Spain; (J.A.R.-G.); (A.J.H.); (A.M.E.-O.); (J.L.V.)
- Department of Biochemistry and Molecular Biology, Faculty of Pharmacy, University of Seville, 41012 Seville, Spain;
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7
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Nucleic Acid-Sensing Toll-Like Receptors Play a Dominant Role in Innate Immune Recognition of Pneumococci. mBio 2020; 11:mBio.00415-20. [PMID: 32209688 PMCID: PMC7157524 DOI: 10.1128/mbio.00415-20] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Streptococcus pneumoniae (or pneumococcus) is a highly prevalent human pathogen. Toll-like receptors (TLRs) function as immune sensors that can trigger host defenses against this bacterium. Defects in TLR-activated signaling pathways, including deficiency in the adaptor protein myeloid differentiation factor 88 (MyD88), are associated with markedly increased susceptibility to infection. However, the individual MyD88-dependent TLRs predominantly involved in antipneumococcal defenses have not been identified yet. Here we find that triple knockout mice simultaneously lacking TLR7, TLR9, and TLR13, which sense the presence of bacterial DNA (TLR9) and RNA (TLR7 and TLR13) in the phagolysosomes of phagocytic cells, display a phenotype that largely resembles that of MyD88-deficient mice and rapidly succumb to pneumococcal pneumonitis due to defective neutrophil influx into the lung. Accordingly, TLR7/9/13 triple knockout resident alveolar macrophages were largely unable to respond to pneumococci with the production of neutrophil-attracting chemokines and cytokines. Mice with single deficiencies of TLR7, TLR9, or TLR13 showed unaltered ability to control lung infection but were moderately more susceptible to encephalitis, in association with a decreased ability of microglia to mount cytokine responses in vitro Our data point to a dominant, tissue-specific role of nucleic acid-sensing pathways in innate immune recognition of S. pneumoniae and also show that endosomal TLRs are largely capable of compensating for the absence of each other, which seems crucial to prevent pneumococci from escaping immune recognition. These results may be useful to develop novel strategies to treat infections by antibiotic-resistant pneumococci based on stimulation of the innate immune system.IMPORTANCE The pneumococcus is a bacterium that frequently causes infections in the lungs, ears, sinus cavities, and meninges. During these infections, body defenses are triggered by tissue-resident cells that use specialized receptors, such as Toll-like receptors (TLRs), to sense the presence of bacteria. We show here that pneumococci are predominantly detected by TLRs that are located inside intracellular vacuoles, including endosomes, where these receptors can sense the presence of nucleic acids released from ingested bacteria. Mice that simultaneously lacked three of these receptors (specifically, TLR7, TLR9, and TLR13) were extremely susceptible to lung infection and rapidly died after inhalation of pneumococci. Moreover, tissue-resident macrophages from these mice were impaired in their ability to respond to the presence of pneumococci by producing inflammatory mediators capable of recruiting polymorphonuclear leucocytes to infection sites. This information may be useful to develop drugs to treat pneumococcal infections, particularly those caused by antibiotic-resistant strains.
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8
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Feuerstein R, Gres V, Elias Perdigó N, Baasch S, Freudenhammer M, Elling R, Henneke P. Macrophages Are a Potent Source of Streptococcus-Induced IFN-β. THE JOURNAL OF IMMUNOLOGY 2019; 203:3416-3426. [PMID: 31732532 DOI: 10.4049/jimmunol.1900542] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Accepted: 10/14/2019] [Indexed: 11/19/2022]
Abstract
IFN-β essentially modulates the host response against mucocutaneous colonizers and potential pathogens, such as group B Streptococcus (GBS). It has been reported that the dominant signaling cascade driving IFN-β in macrophages (MΦ) in streptococcal infection is the cGAS-STING pathway, whereas conventional dendritic cells (DC) exploit endosomal recognition by intracellular TLRs. In this study, we revisited this issue by precisely monitoring the phenotypic dynamics in mixed mouse MΦ/DC cultures with GM-CSF, which requires snapshot definition of cellular identities. We identified four mononuclear phagocyte populations, of which two were transcriptionally and morphologically distinct MΦ-DC-like subsets, and two were transitional types. Notably, GBS induced a TLR7-dependent IFN-β signal only in MΦ-like but not in DC-like cells. IFN-β induction did not require live bacteria (i.e., the formation of cytolytic toxins), which are essential for IFN-β induction via cGAS-STING. In contrast to IFN-β, GBS induced TNF-α independently of TLR7. Subsequent to the interaction with streptococci, MΦ changed their immunophenotype and gained some typical DC markers and DC-like morphology. In summary, we identify IFN-β formation as part of the antistreptococcal repertoire of GM-CSF differentiated MΦ in vitro and in vivo and delineate their plasticity.
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Affiliation(s)
- Reinhild Feuerstein
- Institute for Immunodeficiency, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany; and
| | - Vitka Gres
- Institute for Immunodeficiency, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany; and
| | - Núria Elias Perdigó
- Institute for Immunodeficiency, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany; and
| | - Sebastian Baasch
- Institute for Immunodeficiency, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany; and
| | - Mirjam Freudenhammer
- Institute for Immunodeficiency, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany; and.,Center for Pediatrics and Adolescent Medicine, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany
| | - Roland Elling
- Institute for Immunodeficiency, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany; and.,Center for Pediatrics and Adolescent Medicine, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany
| | - Philipp Henneke
- Institute for Immunodeficiency, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany; and .,Center for Pediatrics and Adolescent Medicine, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany
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9
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A Subset of Skin Macrophages Contributes to the Surveillance and Regeneration of Local Nerves. Immunity 2019; 50:1482-1497.e7. [DOI: 10.1016/j.immuni.2019.05.009] [Citation(s) in RCA: 86] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 02/21/2019] [Accepted: 05/17/2019] [Indexed: 11/20/2022]
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10
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Patra V, Wagner K, Arulampalam V, Wolf P. Skin Microbiome Modulates the Effect of Ultraviolet Radiation on Cellular Response and Immune Function. iScience 2019; 15:211-222. [PMID: 31079025 PMCID: PMC6515114 DOI: 10.1016/j.isci.2019.04.026] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Revised: 01/18/2019] [Accepted: 04/19/2019] [Indexed: 12/26/2022] Open
Abstract
The skin is colonized by a diverse microbiome intricately involved in various molecular and cellular processes within the skin and beyond. UV radiation is known to induce profound changes in the skin and modulate the immune response. However, the role of the microbiome in UV-induced immune suppression has been overlooked. By employing the standard model of contact hypersensitivity (using germ-free mice) we found diminished UV-induced systemic immune suppression in the presence of microbiome. Upon UV exposure, we found enhanced epidermal hyperplasia and neutrophilic infiltration in the presence and enhanced numbers of mast cells and monocyte or macrophages in the absence of microbiome. Transcriptome analysis revealed a predominant expression of cytokine genes related to pro-inflammatory milieu in the presence versus immunosuppressive milieu (with increased interleukin-10) in the absence of microbiome. Collectively, microbiome abrogates the immunosuppressive response to UV by modulating gene expression and cellular microenvironment of the skin. Epidermal and immune response to UV is dependent on skin microbiome Increased neutrophilic infiltration and expression of IL-1β in SPF mice after UV-R Elevated macrophage infiltration and expression of IL-10 in GF mice after UV-R Skin microbiome diminishes UV-induced immune suppression to contact allergen DNFB
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Affiliation(s)
- VijayKumar Patra
- Center for Medical Research, Medical University of Graz, Graz, Austria; Research Unit for Photodermatology, Department of Dermatology, Medical University of Graz, Graz, Austria; Core Facility for Germfree Research (CFGR), Department of Comparative Medicine and Department of Microbiology, Tumor, and Cell Biology (MTC), Karolinska Institutet, Stockholm, Sweden
| | - Karin Wagner
- Center for Medical Research, Medical University of Graz, Graz, Austria
| | - Velmurugesan Arulampalam
- Core Facility for Germfree Research (CFGR), Department of Comparative Medicine and Department of Microbiology, Tumor, and Cell Biology (MTC), Karolinska Institutet, Stockholm, Sweden
| | - Peter Wolf
- Research Unit for Photodermatology, Department of Dermatology, Medical University of Graz, Graz, Austria.
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11
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Sutton JA, Rogers LM, Dixon B, Kirk L, Doster R, Algood HM, Gaddy JA, Flaherty R, Manning SD, Aronoff DM. Protein kinase D mediates inflammatory responses of human placental macrophages to Group B Streptococcus. Am J Reprod Immunol 2019; 81:e13075. [PMID: 30582878 PMCID: PMC6459189 DOI: 10.1111/aji.13075] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Revised: 12/11/2018] [Accepted: 12/18/2018] [Indexed: 01/22/2023] Open
Abstract
PROBLEM During pregnancy, Group B Streptococcus (GBS) can infect fetal membranes to cause chorioamnionitis, resulting in adverse pregnancy outcomes. Macrophages are the primary resident phagocyte in extraplacental membranes. Protein kinase D (PKD) was recently implicated in mediating pro-inflammatory macrophage responses to GBS outside of the reproductive system. This work aimed to characterize the human placental macrophage inflammatory response to GBS and address the extent to which PKD mediates such effects. METHOD Primary human placental macrophages were infected with GBS in the presence or absence of a specific, small molecule PKD inhibitor, CRT 0066101. Macrophage phenotypes were characterized by evaluating gene expression, cytokine release, assembly of the NLRP3 inflammasome, and NFκB activation. RESULTS GBS evoked a strong inflammatory phenotype characterized by the release of inflammatory cytokines (TNFα, IL-1β, IL-6 (P ≤ 0.05), NLRP3 inflammasome assembly (P ≤ 0.0005), and NFκB activation (P ≤ 0.05). Pharmacological inhibition of PKD suppressed these responses, newly implicating a role for PKD in mediating immune responses of primary human placental macrophages to GBS. CONCLUSION PKD plays a critical role in mediating placental macrophage inflammatory activation in response to GBS infection.
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Affiliation(s)
- Jessica A. Sutton
- Department of Microbiology and Immunology, Meharry Medical College School of Medicine, Nashville, TN, 37208, USA
- Department of Medicine, Division of Infectious Diseases, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Lisa M. Rogers
- Department of Medicine, Division of Infectious Diseases, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Beverly Dixon
- Department of Medicine, Division of Infectious Diseases, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Leslie Kirk
- Department of Medicine, Division of Infectious Diseases, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Ryan Doster
- Department of Medicine, Division of Infectious Diseases, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Holly M. Algood
- Department of Medicine, Division of Infectious Diseases, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Department of Veterans Affairs, Tennessee Valley Healthcare Systems, Nashville, Tennessee, U.S.A
| | - Jennifer A. Gaddy
- Department of Medicine, Division of Infectious Diseases, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Department of Veterans Affairs, Tennessee Valley Healthcare Systems, Nashville, Tennessee, U.S.A
| | - Rebecca Flaherty
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA
| | - Shannon D. Manning
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA
| | - David M. Aronoff
- Department of Microbiology and Immunology, Meharry Medical College School of Medicine, Nashville, TN, 37208, USA
- Department of Medicine, Division of Infectious Diseases, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Department of Obstetrics and Gynecology, Vanderbilt University Medical Center, Nashville, TN, 37232, USA
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12
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Gres V, Kolter J, Erny D, Henneke P. The role of CNS macrophages in streptococcal meningoencephalitis. J Leukoc Biol 2019; 106:209-218. [PMID: 30762892 DOI: 10.1002/jlb.4mr1118-419r] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Revised: 01/14/2019] [Accepted: 01/15/2019] [Indexed: 12/18/2022] Open
Abstract
In the healthy brain, microglia and other CNS macrophages are the most abundant immune cell type. Thus, they form the natural immune cell interface with streptococci, which are the leading cause of bacterial meningitis and encephalitis in infants and young children. In homeostasis, the blood-brain barrier allows for very limited access of immune cells circulating in the periphery. During bacterial meningoencephalitis, however, origin and fate of CNS macrophages are massively altered. This review summarizes the emerging knowledge on the sequence of reciprocal events between streptococci and CNS macrophages leading to host resistance, acute inflammation, changes in resident innate immune cells of the brain, and long-term neuronal damage.
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Affiliation(s)
- Vitka Gres
- Institute for Immunodeficiency, Center for Chronic Immunodeficiency (CCI), Medical Center and Faculty of Medicine, University of Freiburg, Freiburg, Germany.,Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Julia Kolter
- Institute for Immunodeficiency, Center for Chronic Immunodeficiency (CCI), Medical Center and Faculty of Medicine, University of Freiburg, Freiburg, Germany.,Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Daniel Erny
- Institute of Neuropathology, Medical Center and Faculty of Medicine, University of Freiburg, Freiburg, Germany.,Berta-Ottenstein-Programme, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Philipp Henneke
- Institute for Immunodeficiency, Center for Chronic Immunodeficiency (CCI), Medical Center and Faculty of Medicine, University of Freiburg, Freiburg, Germany.,Center for Pediatrics and Adolescent Medicine, Medical Center and Faculty of Medicine, University of Freiburg, Freiburg, Germany
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13
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Franko J, McCall JL, Barnett JB. Evaluating Macrophages in Immunotoxicity Testing. Methods Mol Biol 2018; 1803:255-296. [PMID: 29882145 DOI: 10.1007/978-1-4939-8549-4_17] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/05/2023]
Abstract
Macrophages are a heterogeneous group of cells that have a multitude of functions depending on their differentiation state. While classically known for their phagocytic and antigen presentation abilities, it is now evident that these cells fulfill homeostatic functions beyond the elimination of invading pathogens. In addition, macrophages have also been implicated in the downregulation of inflammatory responses following pathogen removal, tissue remodeling, repair, and angiogenesis. Alterations in macrophage differentiation and/or activity due to xenobiotic exposure can have grave consequences on organismal homeostasis, potentially contributing to disease due to immunosuppression or chronic inflammatory responses, depending upon the pathways affected. In this chapter, we provide an overview of the macrophages subtypes, their origin and a general discussion of several different assays used to assess their functional status.
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Affiliation(s)
- Jennifer Franko
- Department of Microbiology, Immunology and Cell Biology, West Virginia University School of Medicine, Morgantown, WV, USA
| | - Jamie L McCall
- Department of Microbiology, Immunology and Cell Biology, West Virginia University School of Medicine, Morgantown, WV, USA
| | - John B Barnett
- Department of Microbiology, Immunology and Cell Biology, West Virginia University School of Medicine, Morgantown, WV, USA.
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14
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Patras KA, Nizet V. Group B Streptococcal Maternal Colonization and Neonatal Disease: Molecular Mechanisms and Preventative Approaches. Front Pediatr 2018; 6:27. [PMID: 29520354 PMCID: PMC5827363 DOI: 10.3389/fped.2018.00027] [Citation(s) in RCA: 84] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Group B Streptococcus (GBS) colonizes the gastrointestinal and vaginal epithelium of a significant percentage of healthy women, with potential for ascending intrauterine infection or transmission during parturition, creating a risk of serious disease in the vulnerable newborn. This review highlights new insights on the bacterial virulence determinants, host immune responses, and microbiome interactions that underpin GBS vaginal colonization, the proximal step in newborn infectious disease pathogenesis. From the pathogen perspective, the function GBS adhesins and biofilms, β-hemolysin/cytolysin toxin, immune resistance factors, sialic acid mimicry, and two-component transcriptional regulatory systems are reviewed. From the host standpoint, pathogen recognition, cytokine responses, and the vaginal mucosal and placental immunity to the pathogen are detailed. Finally, the rationale, efficacy, and potential unintended consequences of current universal recommended intrapartum antibiotic prophylaxis are considered, with updates on new developments toward a GBS vaccine or alternative approaches to reducing vaginal colonization.
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Affiliation(s)
- Kathryn A Patras
- Division of Host-Microbe Systems & Therapeutics, Department of Pediatrics, University of California, San Diego, La Jolla, CA, United States
| | - Victor Nizet
- Division of Host-Microbe Systems & Therapeutics, Department of Pediatrics, University of California, San Diego, La Jolla, CA, United States.,Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, United States
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15
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Kolter J, Henneke P. Codevelopment of Microbiota and Innate Immunity and the Risk for Group B Streptococcal Disease. Front Immunol 2017; 8:1497. [PMID: 29209311 PMCID: PMC5701622 DOI: 10.3389/fimmu.2017.01497] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Accepted: 10/24/2017] [Indexed: 12/14/2022] Open
Abstract
The pathogenesis of neonatal late-onset sepsis (LOD), which manifests between the third day and the third month of life, remains poorly understood. Group B Streptococcus (GBS) is the most important cause of LOD in infants without underlying diseases or prematurity and the third most frequent cause of meningitis in the Western world. On the other hand, GBS is a common intestinal colonizer in infants. Accordingly, despite its adaption to the human lower gastrointestinal tract, GBS has retained its potential virulence and its transition from a commensal to a dangerous pathogen is unpredictable in the individual. Several cellular innate immune mechanisms, in particular Toll-like receptors, the inflammasome and the cGAS pathway, are engaged by GBS effectors like nucleic acids. These are likely to impact on the GBS-specific host resistance. Given the long evolution of streptococci as a normal constituent of the human microbiota, the emergence of GBS as the dominant neonatal sepsis cause just about 50 years ago is remarkable. It appears that intensive usage of tetracycline starting in the 1940s has been a selection advantage for the currently dominant GBS clones with superior adhesive and invasive properties. The historical replacement of Group A by Group B streptococci as a leading neonatal pathogen and the higher frequency of other β-hemolytic streptococci in areas with low GBS prevalence suggests the existence of a confined streptococcal niche, where locally competing streptococcal species are subject to environmental and immunological selection pressure. Thus, it seems pivotal to resolve neonatal innate immunity at mucous surfaces and its impact on microbiome composition and quality, i.e., genetic heterogeneity and metabolism, at the microanatomical level. Then, designer pro- and prebiotics, such as attenuated strains of GBS, and oligonucleotide priming of mucosal immunity may unfold their potential and facilitate adaptation of potentially hazardous streptococci as part of a beneficial local microbiome, which is stabilized by mucocutaneous innate immunity.
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Affiliation(s)
- Julia Kolter
- Center for Chronic Immunodeficiency (CCI), Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany.,Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Philipp Henneke
- Center for Chronic Immunodeficiency (CCI), Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany.,Center for Pediatrics and Adolescent Medicine, Medical Center - University of Freiburg, Freiburg, Germany
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16
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Ehrnström B, Beckwith KS, Yurchenko M, Moen SH, Kojen JF, Lentini G, Teti G, Damås JK, Espevik T, Stenvik J. Toll-Like Receptor 8 Is a Major Sensor of Group B Streptococcus But Not Escherichia coli in Human Primary Monocytes and Macrophages. Front Immunol 2017; 8:1243. [PMID: 29042860 PMCID: PMC5632357 DOI: 10.3389/fimmu.2017.01243] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Accepted: 09/19/2017] [Indexed: 02/05/2023] Open
Abstract
TLR8 is the major endosomal sensor of degraded RNA in human monocytes and macrophages. It has been implicated in the sensing of viruses and more recently also bacteria. We previously identified a TLR8-IFN regulatory factor 5 (IRF5) signaling pathway that mediates IFNβ and interleukin-12 (IL-12) induction by Staphylococcus aureus and is antagonized by TLR2. The relative importance of TLR8 for the sensing of various bacterial species is however still unclear. We here compared the role of TLR8 and IRF5 for the sensing of Group B Streptococcus (GBS), S. aureus, and Escherichia coli in human primary monocytes and monocyte-derived macrophages (MDM). GBS induced stronger IFNβ and TNF production as well as IRF5 nuclear translocation compared to S. aureus grown to the stationary phase, while S. aureus in exponential growth appeared similarly potent to GBS. Cytokine induction in primary human monocytes by GBS was not dependent on hemolysins, and induction of IFNβ and IL-12 as well as IRF5 activation were reduced with TLR2 ligand costimulation. Heat inactivation of GBS reduced IRF5 and NF-kB translocation, while only the viable E. coli activated IRF5. The attenuated stimulation correlated with loss of bacterial RNA integrity. The E. coli-induced IRF5 translocation was not inhibited by TLR2 costimulation, suggesting that IRF5 was activated via a TLR8-independent mechanism. Gene silencing of MDM using siRNA revealed that GBS-induced IFNβ, IL-12-p35, and TNF production was dependent on TLR8 and IRF5. In contrast, cytokine induction by E. coli was TLR8 independent but still partly dependent on IRF5. We conclude that TLR8-IRF5 signaling is more important for the sensing of GBS than for stationary grown S. aureus in human primary monocytes and MDM, likely due to reduced resistance of GBS to phagosomal degradation and to a lower production of TLR2 activating lipoproteins. TLR8 does not sense viable E. coli, while IRF5 still contributes to E. coli-induced cytokine production, possibly via a cytosolic nucleic acid sensing mechanism.
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Affiliation(s)
- Birgitta Ehrnström
- Centre of Molecular Inflammation Research, Department of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology, Trondheim, Norway.,Department of Infectious Diseases, Clinic of Medicine, St. Olavs Hospital HF, Trondheim University Hospital, Trondheim, Norway
| | - Kai Sandvold Beckwith
- Centre of Molecular Inflammation Research, Department of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology, Trondheim, Norway
| | - Mariia Yurchenko
- Centre of Molecular Inflammation Research, Department of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology, Trondheim, Norway
| | - Siv Helen Moen
- Centre of Molecular Inflammation Research, Department of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology, Trondheim, Norway
| | - June Frengen Kojen
- Centre of Molecular Inflammation Research, Department of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology, Trondheim, Norway
| | - Germana Lentini
- Centre of Molecular Inflammation Research, Department of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology, Trondheim, Norway.,Department of Clinical and Experimental Medicine, University of Messina, Messina, Italy
| | - Giuseppe Teti
- Department of Clinical and Experimental Medicine, University of Messina, Messina, Italy
| | - Jan Kristian Damås
- Centre of Molecular Inflammation Research, Department of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology, Trondheim, Norway.,Department of Infectious Diseases, Clinic of Medicine, St. Olavs Hospital HF, Trondheim University Hospital, Trondheim, Norway
| | - Terje Espevik
- Centre of Molecular Inflammation Research, Department of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology, Trondheim, Norway
| | - Jørgen Stenvik
- Centre of Molecular Inflammation Research, Department of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology, Trondheim, Norway.,Department of Infectious Diseases, Clinic of Medicine, St. Olavs Hospital HF, Trondheim University Hospital, Trondheim, Norway
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