LPS-induced gene expression in wildtype and MAL knockout mouse macrophages
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ABSTRACT: Comparison of gene expression in WT and MAL knockout (MALKO) mouse macrophages treated with 10ng/ml lipopolysaccharide (LPS) with that of mock-treated cells incubated for the same time (10 days). Cells from 4 mice of each genotype were used and each individual served as its own control. Hybridizations of treated and control samples were dye swapped. Two experiments: WT vs. LPS-treated WT, and MALKO vs. LPS-treated MALKO. 4 individual biological replicates for each genotype, and each mouse served as its own mock control.
Project description:We characterized the CDK9 and Hes1 occupancy on gene loci in conditions of unstimuated and LPS stimualtion in BMDMs BMDMs were left untreated or stimulated with LPS for 1 hour. CDK9 or Hes1 ChIP was performed and the DNA products were subject to ChIPseq
Project description:We characterized the RNA polymerase II occupancy on gene loci in WT and Hes1 KO BMDMs under untreated and LPS-stimulated conditions WT and Hes1 KO BMDMs were left untreated or stimulated with LPS for 1 hour. Pol II ChIP was performed and the DNA products were subject to ChIPseq
Project description:mRNA microarray analysis of bone marrow derived macrophages treated under four conditions, including Naïve (N). Bone marrow derived macrophages (BMDM) were derived from the bone marrow of mice and cultured in the presence of PAO, IFN-gamma, or lipopolysaccharide (LPS). Profiled groups include Naive, LPS, IFN, PAO. Compared each of the groups (PAO, LPS, IFN) with Naïve group.
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. The gene expression profile of macrophages from C57BL/6 and MD-2-deficient mice following either 10 ng LPS /mL, 100 ng lipid A/mL or 10 nM Pam2 stimulation for 2 hours were compared to PBS-stimulated control cells . In vitro differentiated macrophages from two individual WT and MD-2-deficient mice were cultured and stimulated with agonists separately, comparing the gene expression to PBS-stimulated control cells from the same mouse. Comparisons of PBS-stimulated WT cells to PBS-stimulated MD-2-deficient cells were performed to directly compare basal gene expression in the two genotypes.
Project description:Gene level expression estimate using the Whole Transcript (WT) Assay approach of the Gene 1.0 ST Array System for Mouse. This assay was done to identify the RIPK1-dependent gene expression changes in mouse BMDMs. Cost-effective gene-level analysis based on whole-transcript coverage. We analyzed Bone Marrow Derived Macrophages (BMDMs) under 4 different conditions (Control, LPS, LPS/zVAD, LPS/zVAD/Nec-1) to assess inflammatory changes in RIPK1 kinase dependent manner compared to LPS, LPS/zVAD plus RIPK1 inhibitor Nec-1 and control.
Project description:TLR ligands consistently induce expression of two Hes family members Hes1 and Hey1 in macrophages.To evaluate the effects of these two factors on inflammatory responses, we generated mice lacking both Hes1 and Hey1 (DKO). WT and DKO BMDMs were then untreated or exposed to LPS for 3 hours, and microarray was performed to examine global gene expression profiles to identify Hes1 and Hey1-regulated inflammatory genes Examination of Hes1 and Hey1-regulated inflammatory genes in macrophages
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.
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
Project description:A20 is a negative regulator of NF-κB signaling, crucial to control inflammatory responses and ensure tissue homeostasis. A20 is thought to restrict NF-κB activation both by its ubiquitin-editing activity as by non-enzymatic activities. Besides its role in NF-κB signaling, A20 also acts as a protective factor inhibiting apoptosis and necroptosis. Because of the ability of A20 to both ubiquitinate and deubiquitinate substrates and its involvement in many cellular processes, we hypothesized that deletion of A20 might generally impact on protein levels, thereby disrupting cellular processes. We performed a differential proteomics study of bone marrow derived macrophages (BMDMs) from control and myeloid-specific A20 knockout mice, both in untreated conditions and after LPS and TNF treatment, and demonstrate proteome-wide changes in protein expression upon A20 deletion. Several inflammatory proteins are up-regulated in the absence of A20, even without an inflammatory stimulus. Depending on the treatment and the time, more proteins are regulated. Together these changes may affect multiple signaling pathways disturbing tissue homeostasis and inducing (autoimmune) inflammation, as suggested by genetic studies in patients.
Project description:Hepatic macrophages and regulatory T cells (Tregs) play an important role in the maintenance of liver immune homeostasis, but the mechanism by which hepatic macrophages regulate Tregs in acute liver injury remains largely unknown.We found that the hepatic Treg proportion and β-catenin expression in hepatic macrophages were associated with APAP and D-GalN/LPS-induced acute liver injury. Interestingly, β-catenin was significantly upregulated only in infiltrating macrophages, but not in resident Kupffer cells. Myeloid-specific β-catenin knockout mice showed an increased inflammatory cell infiltration and hepatocyte apoptosis. Moreover, myeloid β-catenin deficiency decreased the hepatic Treg proportion in the injured liver. Mechanistically, in vitro co-culture experiments revealed that macrophage β-catenin modulated its exosome composition, and influenced Tregs differentiation. Using mass spectrometry-based proteomics, we identified that macrophage β-catenin disruption decreased the level of exosomal α-SNAP, which in turn prevents Treg differentiation.