IRF8 regulates transcription of Naips for NLRC4 inflammasome activation
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ABSTRACT:
PROVIDER: PRJNA433766 | ENA |
REPOSITORIES: ENA
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Project description:Inflammasome activation is critical for host defense against various microbial infections. Activation of the NLRC4 inflammasome requires detection of flagellin or type III secretion system (T3SS) components by NLR family apoptosis inhibitory proteins (NAIPs); yet how this pathway is regulated is unknown. Here we found that interferon regulatory factor 8 (IRF8) is required for optimal activation of the NLRC4 inflammasome in bone marrow-derived macrophages infected with Salmonella Typhimurium, Burkholderia thailandensis, or Pseudomonas aeruginosa but is dispensable for activation of the canonical and non-canonical NLRP3, AIM2, and Pyrin inflammasomes. IRF8 governs the transcription of Naips to allow detection of flagellin or T3SS proteins to mediate NLRC4 inflammasome activation. Furthermore, we found that IRF8 confers protection against bacterial infection in vivo, owing to its role in inflammasome-dependent cytokine production and pyroptosis. Altogether, our findings suggest that IRF8 is a critical regulator of NAIPs and NLRC4 inflammasome activation for defense against bacterial infection.
2018-04-27 | GSE110452 | GEO
Project description:Inflammasomes are intracellular innate immune sensors that respond to pathogen and damage-associated signals with the proteolytic cleavage of caspase-1, resulting in IL-1_ and IL-18 secretion and macrophage pyroptosis. The discovery that heterozygous gain-of-function mutations in NLRP3 lead to oversecretion of IL-1_ and cause the autoinflammatory disease spectrum Cryopyrin Associated Periodic Syndrome (CAPS), led to the successful use of IL-1 blocking therapies1. We found that a de novo missense mutation in the regulatory domain of the NLRC4 (IPAF, CARD12) inflammasome causes early-onset recurrent fever flares and Macrophage Activation Syndrome (MAS). Functional analyses demonstrated spontaneous production of the inflammasome-dependent cytokines IL-1² and IL-18 exceeding levels in CAPS patients. The NLRC4 mutation led to constitutive caspase-1 cleavage in transduced cells and enhanced spontaneous production of IL-18 by both patient and NLRC4 mutant macrophages. Thus, we describe a novel monoallelic inflammasome defect that expands the autoinflammatory paradigm to include MAS and suggests novel targets for therapy. Whole blood RNA-seq from seven timepoints of one patient with NLRC4-MAS as compared to five healthy pediatric controls, 7 NOMID patients with active disease prior to anakinra treatment and the same 7 NOMID patients with inactive disease after anakinra treatment. Please note that seven time points are chronologic time point. They are ordinal, in that "1" was drawn before "2", but the distance in time between points is not constant. Thus, time points 4 through 7 correspond to samples drawn while the patient was well AND on treatment. However there may be differences between 4 and 7 pertaining to the length of treatment, and for that reason any of these samples were not considered replicates.
2014-09-08 | E-GEOD-57253 | biostudies-arrayexpress
Project description:Inflammasomes are intracellular innate immune sensors that respond to pathogen and damage-associated signals with the proteolytic cleavage of caspase-1, resulting in IL-1_ and IL-18 secretion and macrophage pyroptosis. The discovery that heterozygous gain-of-function mutations in NLRP3 lead to oversecretion of IL-1_ and cause the autoinflammatory disease spectrum Cryopyrin Associated Periodic Syndrome (CAPS), led to the successful use of IL-1 blocking therapies1. We found that a de novo missense mutation in the regulatory domain of the NLRC4 (IPAF, CARD12) inflammasome causes early-onset recurrent fever flares and Macrophage Activation Syndrome (MAS). Functional analyses demonstrated spontaneous production of the inflammasome-dependent cytokines IL-1² and IL-18 exceeding levels in CAPS patients. The NLRC4 mutation led to constitutive caspase-1 cleavage in transduced cells and enhanced spontaneous production of IL-18 by both patient and NLRC4 mutant macrophages. Thus, we describe a novel monoallelic inflammasome defect that expands the autoinflammatory paradigm to include MAS and suggests novel targets for therapy.
2014-09-08 | GSE57253 | GEO
Project description:Short interspersed element (SINE) RNAs are upregulated by cellular stresses1 (heat shock, DNA damage and viral infection) and accumulate in human diseases (macular degeneration2, lupus3, and Alzheimer’s disease4). These transcripts activate inflammasomes5, a family of cytoplasmic multiprotein complexes that sense danger molecules and initiate innate immune responses by activating caspase-1-dependent cytokine production and inflammatory death6, but the molecular sensor of SINE RNAs is unknown. Here, we identify DDX17, a member of the DEAD box family of RNA helicases7, as a sensor of SINE RNAs requisite for inflammasome activation. Induction of caspase-1 cleavage and release of IL-1 and IL-18 by SINE RNAs requires dual recruitment of NLRP3 and NLRC4 but proceeds independent of NAIPs, immune sensors required for canonical NLRC4 activation by bacterial proteins8,9. Instead, SINE RNAs trigger DDX17–NLRC4 interaction, which licenses inflammasome activation. We also report increased levels of DDX17 protein and association of DDX17 and NLRC4 in the retinal pigmented epithelium (RPE) of human eyes with an advanced, untreatable form of age-related macular degeneration (AMD). Disrupting DDX17–NLRC4 signalling blocks SINE RNA-induced inflammasome activation in human RPE cells and RPE degeneration in an animal model of AMD. Our findings uncover a non-canonical mode of inflammasome activation by endogenous retrotransposon transcripts, and provide new potential targets for macular degeneration and potentially other diseases.
2022-06-09 | PXD016019 | Pride
Project description: Not available
| S-EPMC5935577 | biostudies-literature
Project description:Microglia and neuroinflammation play an important role in the development and progression of Alzheimer’s disease (AD). Inositol polyphosphate-5-phosphatase D (INPP5D) is a myeloid-expressed gene genetically-associated with AD. Through unbiased analyses of RNA and protein profiles in INPP5D-disrupted iPSC-derived human microglia, we find that reduction in INPP5D activity is associated with molecular profiles consistent with disrupted autophagy and inflammasome activation. These findings are validated through targeted pharmacological experiments which demonstrate that reduced INPP5D activity induces the formation of the NLRP3 inflammasome, cleavage of CASP1, and secretion of IL-1 and IL-18. Further, in-depth analyses of human brain tissue across hundreds of individuals using a multi-analytic approach provides evidence that a reduction in function of INPP5D in microglia results in inflammasome activation in AD. These findings provide insights into the molecular mechanisms underlying microglia-mediated processes in AD and highlight the inflammasome as a potential therapeutic target for modulating INPP5D-mediated vulnerability to AD.
2024-01-26 | PXD046040 | Pride
Project description: Not available
| S-EPMC7863722 | biostudies-literature
Project description:The activation of the NLRP3 inflammasome is spatiotemporally orchestrated by various organelles, but the precise roles of lysosomes are still unclear. Here we show the vital role of the Ragulator complex, a lysosomal protein, in NLRP3 inflammasome activation. Deficiency of Lamtor1, an essential component of the Ragulator complex, abrogated NLRP3 inflammasome activation in murine macrophage and human monocytic cells. Myeloid-specific Lamtor1-deficient mice showed remarkable attenuation of the severity of NLRP3-associated inflammatory diseases, including LPS-induced sepsis, alum-induced peritonitis, and monosodium urate (MSU)-induced arthritis. Mechanistically, Lamtor1 interacted with histone deacetylase 6 (HDAC6) during NLRP3 inflammasome activation, and this interaction augmented the interaction between the Ragulator complex and NLRP3. Lack of HDAC6 attenuated the interaction between Lamtor1 and NLRP3, resulting in insufficient NLRP3 inflammasome activation. Furthermore, DL-all-rac-α-tocopherol inhibited Lamtor1–HDAC6 interaction, resulting in diminished NLRP3 inflammasome activation. DL-all-rac-α-tocopherol alleviated acute gouty arthritis and MSU-induced peritonitis. Our results provide insight into the role of lysosomes in providing a platform for the activation of NLRP3 inflammasomes by the Ragulator complex.
2022-11-29 | PXD033497 | Pride
Project description:Inflammasome, activated by pathogen-derived and host-derived danger signals, constitutes a multimolecular signaling complex that serves as a platform for caspase-1 (CASP1) activation and interleukin-1beta (IL1B) maturation. The activation of NLRP3 inflammasome requires two-step signals. The first “priming” signal (Signal 1) enhances gene expression of inflammasome components. The second “activation” signal (Signal 2) promotes the assembly of inflammasome components. Deregulated activation of NLRP3 inflammasome contributes to the pathological processes of Alzheimer’s disease (AD) and multiple sclerosis (MS). However, at present, the precise mechanism regulating NLRP3 inflammasome activation and deactivation remains largely unknown. By genome-wide gene expression profiling, we studied the molecular network of NLRP3 inflammasome activation-responsive genes in a human monocyte cell line THP-1 sequentially given two-step signals. We identified the set of 83 NLRP3 inflammasome activation-responsive genes. Among them, we found the NR4A nuclear receptor family NR4A1, NR4A2, and NR4A3, the EGR family EGR1, EGR2, and EGR3, the IkappaB family NFKBIZ, NFKBID, and NFKBIA as a key group of the genes that possibly constitute a negative feedback loop for shutting down inflammation following NLRP3 inflammasome activation. By molecular network analysis, we identified a complex network of NLRP3 inflammasome activation-responsive genes involved in cellular development and death, and immune and inflammatory responses, where transcription factors AP-1, NR4A, and EGR serve as a hub. Thus, NLRP3 inflammasome activation-responsive genes constitute the molecular network composed of a set of negative feedback regulators for prompt resolution of inflammation. To load the Signal 1 (S1), THP-1 cells were incubated for 3 hours in the culture medium with or without inclusion of 0.2 microgram/ml lipopolysaccharide (LPS). To load the Signal 2 (S2), they were incubated further for 2 hours in the culture medium with inclusion of 10 microM nigericin sodium salt dissolved in ethanol or the equal v/v% concentration of ethanol (vehicle), followed by processing for microarray analysis on Human Gene 1.0 ST Array (Affymetrix).
2014-07-01 | E-GEOD-58959 | biostudies-arrayexpress
Project description:This experiment was performed to analyze the contribution of NLRP3 inflammasome activation to age-related changes in hippocampal RNA. The hypothesis was that decreased inflammasome activation would reduce hippocampal inflammation. Results indicate that inflammasome knockout animals are protected from age-related changes in hippocampal gene expression Gene expression profiles of young (1 month) and old (21-23 month) wild type, CIAS -/- and ASC -/- mouse hippocampal tissue were compared. Total mRNA was extracted using Trizol.
2013-09-05 | E-GEOD-43034 | biostudies-arrayexpress