Homo sapiens
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ABSTRACT:
PROVIDER: PRJNA244307 | ENA |
REPOSITORIES: ENA
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Project description:The alarmins myeloid-related protein (MRP) 8 and MRP14 are the dominant cytoplasmic proteins in phagocytes. After release by activated phagocytes extracellular MRP8/MRP14 complexes promote inflammation in many diseases, including infections, allergies, autoimmune diseases, rheumatoid arthritis or inflammatory bowel disease. As receptors for the pro-inflammatory effects of human MRP8, the active component of the MRP8/MRP14-complex, Toll-like receptor (TLR) 4 and the multi-ligand receptor of advanced glycation end products (RAGE) are controversial discussed. Using a comparative bioinformatics analysis between genome-wide response patterns of monocytes to MRP8, endotoxin and different cytokines we demonstrated a dominant role of TLR4 during MRP8-mediated phagocyte activation. The relevance of this signaling pathway could be confirmed in independent cell models for TLR4 and RAGE dependent signaling in mouse and man. In addition to well-known proinflammatory functions of MRP8 our systems biology approach unraveled a novel anti-apoptotic effect of MRP8 on monocytes which was confirmed in independent functional experiments. Our data define the dominance of the TLR4-MRP8 axis in activation of human phagocytes which represents a novel attractive target for modulation of overwhelming innate immune responses. We used microarrays to detail the global programme of gene expression underlying cellularisation and identified distinct classes of up-regulated genes during this process. Human blood monocyte stimulated with various stimuli (control, MRP8, LPS, TNF, IL1) were selected for RNA extraction and hybridization on Affymetrix microarrays.
2014-12-12 | E-GEOD-56681 | biostudies-arrayexpress
Project description:The alarmins myeloid-related protein (MRP) 8 and MRP14 are the dominant cytoplasmic proteins in phagocytes. After release by activated phagocytes extracellular MRP8/MRP14 complexes promote inflammation in many diseases, including infections, allergies, autoimmune diseases, rheumatoid arthritis or inflammatory bowel disease. As receptors for the pro-inflammatory effects of human MRP8, the active component of the MRP8/MRP14-complex, Toll-like receptor (TLR) 4 and the multi-ligand receptor of advanced glycation end products (RAGE) are controversial discussed. Using a comparative bioinformatics analysis between genome-wide response patterns of monocytes to MRP8, endotoxin and different cytokines we demonstrated a dominant role of TLR4 during MRP8-mediated phagocyte activation. The relevance of this signaling pathway could be confirmed in independent cell models for TLR4 and RAGE dependent signaling in mouse and man. In addition to well-known proinflammatory functions of MRP8 our systems biology approach unraveled a novel anti-apoptotic effect of MRP8 on monocytes which was confirmed in independent functional experiments. Our data define the dominance of the TLR4-MRP8 axis in activation of human phagocytes which represents a novel attractive target for modulation of overwhelming innate immune responses. We used microarrays to detail the global programme of gene expression underlying cellularisation and identified distinct classes of up-regulated genes during this process.
2014-12-12 | GSE56681 | GEO
Project description:Hyporesponsiveness by phagocytes, a well-known phenomenon in sepsis, is frequently induced by low-dose endotoxin-stimulation of Toll-like-receptor-4 (TLR4) but can also be found under sterile inflammatory conditions. We now demonstrate that the endogenous alarmins myeloid-related protein (MRP) 8 and MRP14 induce phagocyte hyporesponsiveness via chromatin modifications in a TLR4-dependent manner resulting in enhanced survival during murine septic shock. Also during sterile inflammation, polytrauma and burn patients present with initially high MRP serum concentrations identifying these proteins as obvious candidates for triggering secondary hyporesponsiveness in these patients. Interestingly, increased peripartal MRP concentrations prime human neonatal phagocytes for hyporesponsiveness, which was confirmed in murine neonatal endotoxinemia in wildtype and MRP14 -/- mice. Using a comparative bioinformatics analysis between genome-wide response patterns of MRP- and LPS- tolerized monocytes we demonstrated no difference in global gene expression between samples pretreated with either MRP8-MRP14 or LPS. Our data indicate that alarmin-triggered phagocyte tolerance represents a novel regulatory mechanism for the susceptibility of neonates to systemic infections and during sterile inflammation. Human blood monocytes prestimulated with MRP8-MRP14 or LPS and afterwards activated with LPS were selected for RNA extraction and hybridization on Illumina microarrays.
2014-12-12 | E-GEOD-61477 | biostudies-arrayexpress
Project description:Hyporesponsiveness by phagocytes, a well-known phenomenon in sepsis, is frequently induced by low-dose endotoxin-stimulation of Toll-like-receptor-4 (TLR4) but can also be found under sterile inflammatory conditions. We now demonstrate that the endogenous alarmins myeloid-related protein (MRP) 8 and MRP14 induce phagocyte hyporesponsiveness via chromatin modifications in a TLR4-dependent manner resulting in enhanced survival during murine septic shock. Also during sterile inflammation, polytrauma and burn patients present with initially high MRP serum concentrations identifying these proteins as obvious candidates for triggering secondary hyporesponsiveness in these patients. Interestingly, increased peripartal MRP concentrations prime human neonatal phagocytes for hyporesponsiveness, which was confirmed in murine neonatal endotoxinemia in wildtype and MRP14 -/- mice. Using a comparative bioinformatics analysis between genome-wide response patterns of MRP- and LPS- tolerized monocytes we demonstrated no difference in global gene expression between samples pretreated with either MRP8-MRP14 or LPS. Our data indicate that alarmin-triggered phagocyte tolerance represents a novel regulatory mechanism for the susceptibility of neonates to systemic infections and during sterile inflammation.
2014-12-12 | GSE61477 | GEO
Project description:Purpose: To profile the transcriptomes of omental adipose tissues from obese and lean humans. Methods: Omental adipose tissues from obese and lean patients were subjected to RNA-Seq. Results: Differential expression analysis identified 206 dysregulated genes (p-value < 0.05 by moderated t-test and fold change M-bM-^IM-% 2 in obesity) that are known to be involved in a multitude of functions, including response to stress, inflammatory response and leukocyte adhesion. Differential splicing analysis uncovered the possible role of TLR4 RNA splicing in obesity. Our findings suggest that, as a person experiences weight gain/obesity, the adipose splicing pattern of TLR4 transcripts changes in favor of activation of TLR4 signaling, which in turn may contribute to the progression of obesity-related inflammation and complications. Conclusion: This study provides a look into the transcriptome of disease-state adipose tissue in obesity, and demonstrates the potential importance of aberrant RNA splicing and expression in obesity-associated immune dysregulation. Study design is of cross-sectional nature. Seven samples (three obese and four lean) were analyzed.
2015-02-11 | E-GEOD-55008 | biostudies-arrayexpress
Project description:Purpose: To profile the transcriptomes of omental adipose tissues from obese and lean humans. Methods: Omental adipose tissues from obese and lean patients were subjected to RNA-Seq. Results: Differential expression analysis identified 206 dysregulated genes (p-value < 0.05 by moderated t-test and fold change ≥ 2 in obesity) that are known to be involved in a multitude of functions, including response to stress, inflammatory response and leukocyte adhesion. Differential splicing analysis uncovered the possible role of TLR4 RNA splicing in obesity. Our findings suggest that, as a person experiences weight gain/obesity, the adipose splicing pattern of TLR4 transcripts changes in favor of activation of TLR4 signaling, which in turn may contribute to the progression of obesity-related inflammation and complications. Conclusion: This study provides a look into the transcriptome of disease-state adipose tissue in obesity, and demonstrates the potential importance of aberrant RNA splicing and expression in obesity-associated immune dysregulation.
2015-02-11 | GSE55008 | GEO
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: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.
2011-07-30 | E-GEOD-31067 | 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: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 | GSE31067 | GEO