Project description:Inflammasomes are multi-protein complexes that control the production of pro-inflammatory cytokines such as IL-1beta. Inflammasomes play an important role in the control of immunity to tumors and infections, and also in autoimmune diseases, but the mechanisms controlling the activation of human inflammasomes are largely unknown. We found that human activated CD4+CD45RO+ memory T-cells specifically suppress P2X7R-mediated NLRP3 inflammasome activation, without affecting P2X7R-independent NLRP3 or NLRP1 inflammasome activation. The concomitant increase in pro-IL-1β production induced by activated memory T-cells concealed this effect. Priming with IFNβ decreased pro-IL-1β production in addition to NLRP3 inflammasome inhibition and thus unmasked the inhibitory effect on NLRP3 inflammasome activation. IFNβ did not suppress NLRP3 inflammasome activation by acting directly on monocytes. The inhibition of pro-IL-1β production and suppression of NLRP3 inflammasome activation by IFNβ-primed human CD4+CD45RO+ memory T-cells is partly mediated by soluble FasL and is associated with down-regulated P2X7R mRNA expression and reduced response to ATP in monocytes. CD4+CD45RO+ memory T-cells from multiple sclerosis (MS) patients showed a reduced ability to suppress NLRP3 inflammasome activation, however their suppressive ability was recovered following in vivo treatment with IFNβ. Thus, our data demonstrate that human P2X7R-mediated NLRP3 inflammasome activation is regulated by activated CD4+CD45RO+ memory T cells, and provide new information on the mechanisms mediating the therapeutic effects of IFNβ in MS. Memory T-cells were cultured in the presence of monocytes with and without Interferon-beta, resorted and expression profile was determined
Project description:RNA-seq analysis of an in vivo murine model of vulvovaginal candidiasis Murine vaginas were infected with Candida albicans and harvested for RNA-seq analysis 3 days post-infection
Project description:Streptococcus (S.) pneumoniae is the most frequently isolated causative pathogen community-acquired pneumonia, a leading cause of mortality worldwide. We investigated the role of the inflammasome sensor NLRP3 and the inflammasome adapter ASC during S. pneumoniae pneumonia. Detailed analysis of the early inflammatory response in the lung by whole genome transcriptional profiling, we identified several mediators that were differentially expressed between Nlrp3-/- and Asc-/ - mice. WT, Nlrp3- and Asc-deficient mice were intranasally inocculated with Streptococcus pneumoniae D39 and ATCC6303 both at high and low dose. Lung homogenates were harvested and gene expression profiling was performed.
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).
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.
Project description:Inflammasomes are multiprotein platforms of caspase-1 activation. The NLRP3 inflammasome is composed of NLRP3, ASC, and procaspase-1. This inflammasome is activated by various endogenous and exogenous stimuli, including pneumococci, and protects from a variety of microbial pathogens. In the present study, we examined the role of NLRP3 inflammasome components in gene expression in the lung during pneumococcal pneumina.
Project description:The immune system may respond to engineered nanomaterials (ENM) through inflammatory reactions. The NLRP3 inflammasome responds to a wide range of ENM, and its activation is associated with various inflammatory diseases. The objective of the study was to compare the effects of gold ENM of different shapes on NLRP3 inflammasome activation and related signalling pathways. Differentiated THP-1 cells (wildtype, ASC- or NLRP3-deficient), were exposed to PEGylated gold nanorods, nanostars, and nanospheres. Exposed cells were subjected to gene expression analysis. Nanorods, but not nanostars or nanospheres, showed NLRP3 inflammasome activation. ASC- or NLRP3-deficient cells did not show this effect. Gold nanorod-induced NLRP3 inflammasome activation was accompanied by downregulated sterol/cholesterol biosynthesis, oxidative phosphorylation, and purinergic receptor signalling. In conclusion, the shape and surface chemistry of gold nanoparticles determine NLRP3 inflammasome activation.
Project description:The NLRP3 inflammasome plays a central role in antimicrobial defense as well as in the context of sterile inflammatory conditions. NLRP3 activity is governed by two independent signals: The first signal primes NLRP3, rendering it responsive to the second signal, which then triggers inflammasome formation. Our understanding of how NLRP3 priming contributes to inflammasome activation remains limited. Here we show that IKKβ, a kinase activated during priming, induces recruitment of NLRP3 to phosphatidylinositol-4-phosphate (PI4P), a lipid enriched on the trans-Golgi network. Intriguingly, NEK7, a mitotic spindle kinase that had previously been thought to be indispensable for NLRP3 activation, was redundant for inflammasome formation when IKKβ recruited NLRP3 to PI4P. Studying iPSC-derived human macrophages revealed that the IKKβ-mediated NEK7-independent pathway constitutes the predominant NLRP3 priming mechanism in human myeloid cells. Our results suggest that PI4P binding represents a new type of "primed" state into which NLRP3 is brought by IKKβ activity.
Project description:Streptococcus (S.) pneumoniae is the most frequently isolated causative pathogen community-acquired pneumonia, a leading cause of mortality worldwide. We investigated the role of the inflammasome sensor NLRP3 and the inflammasome adapter ASC during S. pneumoniae pneumonia. Detailed analysis of the early inflammatory response in the lung by whole genome transcriptional profiling, we identified several mediators that were differentially expressed between Nlrp3-/- and Asc-/ - mice.