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IFN-γ extends the immune functions of Guanylate Binding Proteins to inflammasome-independent antibacterial activities during Francisella novicida infection
- Source :
- PLoS Pathogens, PLoS Pathogens, Public Library of Science, 2017, 13 (10), pp.e1006630. ⟨10.1371/journal.ppat.1006630⟩, PLoS Pathogens, 2017, 13 (10), pp.e1006630. ⟨10.1371/journal.ppat.1006630⟩, PLoS Pathogens, Vol 13, Iss 10, p e1006630 (2017)
- Publication Year :
- 2017
- Publisher :
- HAL CCSD, 2017.
-
Abstract
- Guanylate binding proteins (GBPs) are interferon-inducible proteins involved in the cell-intrinsic immunity against numerous intracellular pathogens. The molecular mechanisms underlying the potent antibacterial activity of GBPs are still unclear. GBPs have been functionally linked to the NLRP3, the AIM2 and the caspase-11 inflammasomes. Two opposing models are currently proposed to explain the GBPs-inflammasome link: i) GBPs would target intracellular bacteria or bacteria-containing vacuoles to increase cytosolic PAMPs release ii) GBPs would directly facilitate inflammasome complex assembly. Using Francisella novicida infection, we investigated the functional interactions between GBPs and the inflammasome. GBPs, induced in a type I IFN-dependent manner, are required for the F. novicida-mediated AIM2-inflammasome pathway. Here, we demonstrate that GBPs action is not restricted to the AIM2 inflammasome, but controls in a hierarchical manner the activation of different inflammasomes complexes and apoptotic caspases. IFN-γ induces a quantitative switch in GBPs levels and redirects pyroptotic and apoptotic pathways under the control of GBPs. Furthermore, upon IFN-γ priming, F. novicida-infected macrophages restrict cytosolic bacterial replication in a GBP-dependent and inflammasome-independent manner. Finally, in a mouse model of tularemia, we demonstrate that the inflammasome and the GBPs are two key immune pathways functioning largely independently to control F. novicida infection. Altogether, our results indicate that GBPs are the master effectors of IFN-γ-mediated responses against F. novicida to control antibacterial immune responses in inflammasome-dependent and independent manners.<br />Author summary The cell-intrinsic immunity is defined as the mechanisms allowing a host cell infected by an intracellular pathogen to mount effective immune mechanisms to detect and eliminate pathogens without any help from other immune cells. In infected macrophages, the Guanylate Binding Proteins (GBPs) are immune proteins, induced at low levels in a cell autonomous manner by endogenous type I IFN or at high levels following IFN-γ production by innate and adaptive lymphocytes. The antibacterial activity of GBPs has been recently tightly linked to the inflammasomes. Inflammasomes are innate immune complexes leading to inflammatory caspases activation and death of the infected cell. Francisella novicida, a bacterium replicating in the macrophage cytosol, is closely related to F. tularensis, the agent of tularemia and is used as a model to study cytosolic immunity. GBPs contribute to F. novicida lysis within the host cytosol leading to DNA release and AIM2 inflammasome activation. In addition to their regulation of the AIM2 inflammasome, we identified that GBPs also control several other pyroptotic and apoptotic pathways activated in a hierarchical manner. Furthermore, we demonstrate that IFN-γ priming extends GBPs anti-microbial responses from the inflammasome-dependent control of cell death to an inflammasome-independent control of cytosolic bacterial replication. Our results, validated in a mouse model of tularemia, thus segregate the antimicrobial activities of inflammasomes and GBPs as well as highlight GBPs as the master effectors of IFN-γ-mediated cytosolic immunity.
- Subjects :
- 0301 basic medicine
Male
Inflammasomes
Fluorescent Antibody Technique
Apoptosis
medicine.disease_cause
Pathology and Laboratory Medicine
Inbred C57BL
Biochemistry
White Blood Cells
Mice
0302 clinical medicine
Animal Cells
Medicine and Health Sciences
Biology (General)
Francisella
Francisella tularensis
Tularemia
Mice, Knockout
Immune System Proteins
Cell Death
Effector
Antimicrobials
Biochemistry and Molecular Biology
Drugs
Inflammasome
Flow Cytometry
3. Good health
Cell biology
Bacterial Pathogens
Chemistry
Intracellular Pathogens
Cell Processes
Medical Microbiology
Gene Knockdown Techniques
Physical Sciences
[SDV.MP.VIR]Life Sciences [q-bio]/Microbiology and Parasitology/Virology
[SDV.IMM]Life Sciences [q-bio]/Immunology
Female
Cellular Types
Pathogens
medicine.drug
Research Article
QH301-705.5
Immune Cells
Knockout
Immunology
Immunoblotting
Enzyme-Linked Immunosorbent Assay
Biology
Microbiology
03 medical and health sciences
AIM2
Interferon-gamma
Immune system
GTP-Binding Proteins
Virology
Microbial Control
Genetics
medicine
Animals
Francisella novicida
Molecular Biology
Microbial Pathogens
Pharmacology
Blood Cells
Bacteria
Animal
Intracellular parasite
Macrophages
Chemical Compounds
Organisms
Biology and Life Sciences
Proteins
Cell Biology
RC581-607
Iodides
biology.organism_classification
[SDV.MP.BAC]Life Sciences [q-bio]/Microbiology and Parasitology/Bacteriology
Mice, Inbred C57BL
Disease Models, Animal
030104 developmental biology
Disease Models
Antibacterials
Parasitology
Immunologic diseases. Allergy
Gram-Negative Bacterial Infections
Inflammasome complex
Biokemi och molekylärbiologi
030215 immunology
Subjects
Details
- Language :
- English
- ISSN :
- 15537366 and 15537374
- Database :
- OpenAIRE
- Journal :
- PLoS Pathogens, PLoS Pathogens, Public Library of Science, 2017, 13 (10), pp.e1006630. ⟨10.1371/journal.ppat.1006630⟩, PLoS Pathogens, 2017, 13 (10), pp.e1006630. ⟨10.1371/journal.ppat.1006630⟩, PLoS Pathogens, Vol 13, Iss 10, p e1006630 (2017)
- Accession number :
- edsair.doi.dedup.....69481ca1e58d723fddf481a48aea617e