Comparison of TLR4-stimulated mouse microglia from wildtype and CD14ko strains
Ontology highlight
ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE62641 | GEO | 2015/10/23
SECONDARY ACCESSION(S): PRJNA264617
REPOSITORIES: GEO
Similar Datasets
Project description:The analysis reveals the importance of CD14 in microglial responses to pathogen- and damage-associated molecular patterns, based on stimulations with lipopolysaccharide (LPS) and fiibronectin (FN). The data show a dose- and agonist-dependent involvement of CD14. Lack of CD14 impairs responses to low-dose challenegs with LPS, whereas high-dose challenegs are affected to a much lesser degree. For FN, CD14 deficiency causes a major impairment of the response capacity. Mouse microglia from wt and cd14-/- strains were stimulated with 0.1 and 10 ng/ml of LPS or with 100 µg/ml of mouse FN for 3 h. Untreated cells served as the controls. Each condition was based on three independent cell preparations as wells a processing.
2015-10-23 | E-GEOD-62641 | biostudies-arrayexpress
Project description:Dendritic cells (DCs) are a special class of leukocytes able to activate both innate and adaptive immune responses. They interact with microbes through germline-encoded pattern-recognition receptors (PRRs), which recognize molecular patterns expressed by various microorganisms. Upon antigen binding, PRRs instruct DCs for the appropriate priming of natural killer cells, followed by specific T-cell responses. Once completed the effector phase, DCs reach the terminal differentiation stage and eventually die by apoptosis. We have observed that following lipopolysaccharide (LPS)-stimulation the initiation of the apoptotic pathway in DCs is due the activation of NFAT proteins. Indeed, LPS induces Src-family kinase and phospholipase C (PLC)γ2 activation, influx of extracellular Ca2+ and calcineurin-dependent nuclear NFAT translocation. The initiation of this pathway is independent of TLR4 engagement, and dependent exclusively on CD14. According with this observation CD14-deficient DCs do not die following LPS stimulation. Nevertheless, CD14-deficient DC death following LPS activation can be restored by co-stimulating DCs with LPS and thapsigargin. Thapsigargin empties the intracellular calcium stores by blocking calcium pumping into the sarcoplasmic and endoplasmic reticulum and thereby activates plasma membrane calcium channels. This, in turn, allows an influx of calcium into the cytosol and NFAT activation. To identify the NFAT controlled apoptosis genes in LPS activated DCs we have performed a kinetic microarray analysis (0, 48 and 60 h) in conditions allowing or inhibiting NFAT activation. Four genes have been selected: Nur77, Gadd45g, Ddit3/Gadd153/Chop-10 and Tia1. To identify apoptosis genes selectively modulated by NFAT, a comparative kinetic (time points 0, 48 and 60 h) microarray analysis was performed in the following conditions: 1) wild type bone marrow derived DCs (wtBMDCs) stimulated with LPS; 2) CD14-deficient BMDCs stimulated with LPS; 3) wtBMDCs stimulated with LPS in presence of thapsigargin; 4) CD14-deficient BMDCs stimulated with LPS in presence of thapsigargin.
2010-03-03 | E-GEOD-15720 | biostudies-arrayexpress
Project description:This SuperSeries is composed of the following subset Series: GSE19482: Transcriptional responses of human monocyte-derived macrophages (HMDM) to lipopolysaccharide (LPS) GSE19490: Transcriptional responses of mouse BMM and TEPM to lipopolysaccharide (LPS) GSE19765: Transcriptional responses of human monocyte-derived macrophages (HMDM) to lipopolysaccharide (LPS) - Illumina arrays GSE19766: Transcriptional responses of mouse bone marrow-derived macrophages (BMM) to lipopolysaccharide (LPS) - Illumina arrays Refer to individual Series
2012-03-28 | E-GEOD-19492 | biostudies-arrayexpress
Project description:Lipid A (a hexaacylated 1,4 bis-phosphate) is a potent immune stimulant for TLR4/MD-2. Upon lipid A ligation, the TLR4/MD-2 complex dimerizes and initiates signal transduction. Historically, studies also suggested the existence of TLR4/MD-2-independent LPS signaling. Here we define the role of TLR4 and MD-2 in LPS signaling by using genome wide expression profiling in TLR4- and MD-2-deficient macrophages after stimulations with peptidoglycan-free LPS and synthetic E.coli lipid A. Of the 1,396 genes found significantly induced or repressed by any one of the treatments in the wildtype macrophages, none was present in the TLR4- or MD-2-deficient macrophages, confirming that the TLR4/MD-2 complex is the only receptor for endotoxin, and are both absolutely required for responses to LPS. Using a molecular genetics approach, we investigated the mechanism of TLR4/MD-2 activation by combining the known crystal structure of TLR4/MD-2 with computer modeling. We used lipid IVa, a defined lipid A mimetic to model the activation of mouse TLR4/MD2. The two phosphates on lipid A were predicted to interact extensively with the two positively charged patches mouse TLR4 according to our dimeric murine TLR4/MD-2/lipid IVa model. These two patches are composed of K263, R337, and K360 (Positive Patch 1), and K367 and R434 (Positive Patch 2). When either Positive Patch was abolished by mutagenesis into Ala, the responses to LPS and lipid A were almost abrogated. Thus, ionic interactions between the two phosphates on lipid A and the two positively charged patches on murine TLR4 appear to be essential for LPS receptor activation.
2011-07-31 | GSE31066 | GEO
Project description:Macrophages and dendritic cells (DCs) differently contribute to the generation of coordinated immune system responses against infectious agents. They interact with microbes through germline-encoded pattern-recognition receptors (PRRs), which recognize molecular patterns expressed by various microorganisms. Upon antigen binding, PRRs instruct DCs for the appropriate priming of natural killer cells, followed by specific T-cell responses. Once completed the effector phase, DCs reach the terminal differentiation stage and eventually die by apoptosis. By contrast, following antigen recognition, macrophages initiate first the inflammatory process and then switch to an anti-inflammatory phenotype for the restoration of tissue homeostasis. Following lipopolysaccharide (LPS)-stimulation the initiation of the apoptotic pathway in DCs is due the activation of NFAT proteins. DC stimulation with lipopolysaccharide (LPS) induces Src-family kinase and phospholipase C (PLC)γ2 activation, influx of extracellular Ca2+ and calcineurin-dependent nuclear NFAT translocation. The initiation of this pathway is independent of TLR4 engagement, and dependent exclusively on CD14. We asked whether macrophage survival after LPS encounter was due to their inability to activate the Ca2+ pathway. As matter of fact, bone marrow-derived macrophages were unable to mobilize Ca2+ and to translocate NFAT to the. To further investigate whether the Ca2+-NFAT pathway played any role in LPS-stimulated macrophages, we performed a comparative kinetic microarray analysis in conditions allowing or inhibiting NFAT activation. We show here that no modulation of gene expression can be attributed to NFAT. Gene expression analyses were performed using Affymetrix GeneChips in the following groups of murine macrophaghes: 1) CD14-deficient macrophages stimulated with LPS; 2) wt macrophages stimulated with LPS in presence of EGTA; 3) wt macrophages stimulated with LPS. The following kinetic time points were examined: 0, 6 and 24 hours following LPS activation. This experimental setting allowed us to select for effects due to Ca2+ fluxes and exclude the effects due to other causes, particularly the block of TRIF recruitment in CD14-deficient cells and the EGTA effects unrelated to Ca2+ chelation.
2010-03-04 | E-GEOD-15721 | biostudies-arrayexpress
Project description:Lipid A (a hexaacylated 1,4 bis-phosphate) is a potent immune stimulant for TLR4/MD-2. Upon lipid A ligation, the TLR4/MD-2 complex dimerizes and initiates signal transduction. Historically, studies also suggested the existence of TLR4/MD-2-independent LPS signaling. Here we define the role of TLR4 and MD-2 in LPS signaling by using genome wide expression profiling in TLR4- and MD-2-deficient macrophages after stimulations with peptidoglycan-free LPS and synthetic E.coli lipid A. Of the 1,396 genes found significantly induced or repressed by any one of the treatments in the wildtype macrophages, none was present in the TLR4- or MD-2-deficient macrophages, confirming that the TLR4/MD-2 complex is the only receptor for endotoxin, and are both absolutely required for responses to LPS. Using a molecular genetics approach, we investigated the mechanism of TLR4/MD-2 activation by combining the known crystal structure of TLR4/MD-2 with computer modeling. We used lipid IVa, a defined lipid A mimetic to model the activation of mouse TLR4/MD2. The two phosphates on lipid A were predicted to interact extensively with the two positively charged patches mouse TLR4 according to our dimeric murine TLR4/MD-2/lipid IVa model. These two patches are composed of K263, R337, and K360 (Positive Patch 1), and K367 and R434 (Positive Patch 2). When either Positive Patch was abolished by mutagenesis into Ala, the responses to LPS and lipid A were almost abrogated. Thus, ionic interactions between the two phosphates on lipid A and the two positively charged patches on murine TLR4 appear to be essential for LPS receptor activation. Bone marrow-derived macrophages were pooled from four individual WT or TLR4-deficient mice and stimulated with either 10 ng LPS /mL, 100 ng lipid A/mL or 10 nM Pam2 for 2 hours and compared to PBS-stimulated control cells. We also compared PBS-stimulated WT cells directly to PBS-stimulated TLR4-deficient cells to compare the basal expression of genes in the two genotypes. This experiment was repeated once in its entirety.
2011-07-30 | E-GEOD-31066 | biostudies-arrayexpress
Project description:A number of studies have proposed that excess food intake, particularly of high fat diets arise due dysregulation of homeostatic mechanisms regulating neuroendocrine control of appetite and energy balance. Current dogma suggests high fat diets invoke hypothalamic inflammation which reduces hypothalamic sensitivity to metabolic and hormonal cues of conveying peripheral status of energy balance, such as leptin and insulin. A hypothesis for the mechanism leading to hypothalamic inflammation is based on high fat diet mediated changes in gut microbiota which are then proposed to increase circulating levels of lipopolysaccharide (LPS). This in turn activates a hypothalamic inflammatory response via the toll-like receptor (TLR4) and CD14. The aim of this study was to determine hypothalamic gene expression in response to long term feeding of a high fat diet, taking into account the importance of using a control diet with a similar composition and balanced for sucrose content.
2018-10-23 | E-MTAB-6929 | biostudies-arrayexpress
Project description:This SuperSeries is composed of the following subset Series: GSE31066: Lipopolysaccharide (LPS) response in macrophages from TLR4-deficient mice GSE31067: Lipopolysaccharide (LPS) response in macrophages from MD-2-deficient mice Refer to individual Series
2011-07-30 | E-GEOD-31078 | biostudies-arrayexpress
Project description:Host defense against bacterial and fungal infections diminishes with age. In humans, this is thought to be caused in part by a decline in neutrophil responses. However, it remains unclear whether a similar decline in neutrophil function occurs in mice. Here, we show that old mice have a reduced capacity to clear pathogenic E. coli during septic peritonitis. Neutrophil recruitment to the peritoneum was elevated during lipopolysaccharide (LPS)-induced septic peritonitis but not aseptic peritonitis. Neutrophils from old mice showed reduced chemoattractant-induced reactive oxygen species (ROS) production upon priming with LPS but not GM-CSF/TNF. Phagocytosis and degranulation were reduced in a partially LPS-dependent manner, whereas NETosis was impaired independently of LPS. The chemoattractant-stimulated production of PIP3 was reduced upon priming with LPS but not GM-CSF/TNF, whereas PI(4,5)P2 levels were constitutively low. Unexpectedly, chemotaxis was normal regardless of priming pathway, as were the chemoattractant-stimulated activities of Rac1 and Rac2. The expression of 5% of neutrophil proteins was deregulated in old age. Granule proteins, particularly cathepsins and serpins, as well as toll-like receptor (TLR) pathway proteins and membrane receptors were upregulated, whereas chromatin and RNA regulators were downregulated. Upregulation of Cd180 and downregulation of MyD88 may contribute to the impaired LPS priming and LPS-dependent PIP3 production. In summary, all major neutrophil responses except chemotaxis decline with age in mice, particularly upon LPS priming. This LPS-TLR4 pathway dependence resolves some of the controversy regarding the effects of age on murine neutrophils and confirms mice are an appropriate model for the declining human neutrophil function.
2022-08-20 | PXD035577 | Pride
Project description:In this study we performed single-cell transcriptome analysis of THP-1 macrophages, stimulated with high levels of free fatty acids (palmitate, PAL) typical for obese adipose tissue microenvironment or lipopolysaccharide (LPS), representing a classical stimulus activating innate immune response. Analysing full transcriptomes of individual cells, we were able to distinguish 3 macrophage transcriptional states and decipher gene regulatory pathways underlying macrophage state identity in both stimulations.
2019-05-15 | E-MTAB-6075 | biostudies-arrayexpress