RNA-Sequencing of LPS-stimulated TLR4 HEK293 cells edited at an immune-response trans-eQTL locus
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ABSTRACT:
PROVIDER: PRJNA607299 | ENA |
REPOSITORIES: ENA
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Project description:In order to investigate the genetic effect of an IRF1-associated immune-response trans-eQTL, we used CRISPR editing to introduce deletions at the top variant rs17622517. Five unedited, three heterozygous and five homozygous clones were isolated and RNA-sequencing was performed with no stimulation, with 90min LPS stimulation and 12h LPS stimulation, with two replicates of each. We find a significant correlation between the genetic perturbation here and CRISPRi perturbation of the variant locus, as well as the trans-eQTL effects, suggesting this variant is the causal variant for the immune-response trans-eQTL.
2020-02-19 | GSE145486 | GEO
Project description:We developed and optimized a new electroporation protocol for CRISPR-Cas9 gene editing. This protocol achieved up to 68% success rate, when applied to isolated hMSCs from the heart and epicardial fat of patients with ischemic heart disease. While cell editing resulted lowered TLR4 expression in hMSCs, it did not affect classical markers of hMSCs and proliferation rate. Advanced protein mass spectrometry analysis revealed that edited cells secreted fewer proteins involved in inflammation and in extracellular matrix organization. The immunomodulatory effect of TLR4 editing was apparent in both free and EV-encapsulated proteins. Furthermore, edited cells expressed less NF-ƙB and secreted lower amounts of extracellular vesicles, pro-inflammatory and pro-fibrotic cytokines than unedited hMSCs. Cell therapy with edited and unedited hMSCs improved survival, left ventricular (LV) remodeling, and cardiac function after myocardial infarction (MI) in mice. Postmortem histologic analysis revealed clusters of edited cells that survived in the scar tissue 28 days after MI. Morphometric analysis showed that implantation of edited cells increased the area of myocardial islands in the scar tissue, reduced the occurrence of transmural scar, increased scar thickness, and markedly decreased expansion index, compared with unedited cells or saline.
2023-05-10 | PXD033253 | Pride
Project description:RNA-Sequencing of LPS-stimulated TLR4 HEK293 cells with CRISPRi treatment at an immune enhancer
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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. 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:BACKGROUND & AIMS: TLR4 is an innate immune receptor with expression in human skin, keratinocytes as well as squamous cell carcinoma (SCC) of the skin. In the present study we investigate the role of TLR4 as a negative regulator of keratinocyte proliferation. We present here that the expression of TLR4 increased with the differentiation of cultured keratinocytes in a passage-dependent manner or under calcium-rich conditions. Moreover, the down-regulation of TLR4 by specific knockdown increased the proliferation of primary normal, SCC-derived and HaCaT keratinocytes in vitro. In addition, subcutaneously injected HaCaT keratinocytes with shTLR4 formed growing tumors in nude mice. In contrast, we observed lower proliferation and increased migration in vitro of the SCC13 cell line stably overexpressing TLR4 in comparison to SCC13 TLR4 negative cells. In vivo, SCC13 TLR4-overexpressing tumors showed delayed growth in comparison to TLR4 negative tumors. The overexpression of TLR4 in SCC13 tumor cells was followed by phosphorylation of ERK1/2 and JNK and increased expression of ATF3. In gene expression arrays, the overexpression of TLR4 in tumor cells correlated with gene expression of ATF-3, IL-6, CDH13, CXCL-1, and TFPI. In summary, TLR4 negatively regulates the proliferation of primary keratinocytes and its overexpression reduces tumor growth of SCC cells.
2016-11-16 | GSE89856 | GEO
Project description:Siglec-E is a murine CD33-related siglec that functions as an inhibitory receptor and is expressed mainly on neutrophils and macrophage populations. Recent studies have suggested that siglec-E is an important negative regulator of LPS-TLR4 signalling and one report (Wu et al 2016) claimed that siglec-E is required for TLR4 endocytosis following uptake of Escherichia coli by macrophages and dendritic cells (DCs). Our attempts to reproduce these observations using cells from wildtype (WT) and siglec E deficient mice were unsuccessful. We used a variety of assays to determine if siglec-E expressed by different macrophage populations can regulate TLR-4 signalling in response to LPS, but found no consistent differences in cytokine secretion in vitro and in vivo, comparing 3 different strains of siglec-E-deficient mice with matched WT controls. No evidence was found that the siglec-E deficiency was compensated by expression of siglecs-F and –G, the other murine inhibitory CD33-related siglecs. Quantitative proteomics was used as an unbiased approach and provided additional evidence that siglec-E does not suppress inflammatory TLR4 signaling. Interestingly, proteomics revealed a siglec E dependent alteration in macrophage phenotype that could be relevant to functional responses in host defence. In support of this, siglec-E-deficient mice exhibited enhanced growth of Salmonella enterica serovar Typhimurium in the liver following intravenous infection, but macrophages lacking siglec-E did not show altered uptake or killing of bacteria in vitro. Using various cell types including bone marrow derived DCs (BMDC), splenic DCs and macrophages from WT and siglec-E-deficient mice, we showed that siglec-E is not required for TLR4 endocytosis following E.coli uptake or LPS challenge. We failed to see expression of siglec-E by BMDC even after LPS-induced maturation, but confirmed previous studies that splenic DCs express low levels of siglec-E. Taken together, our findings do not support a major role of siglec-E in regulation of TLR4 signalling functions or TLR4 endocytosis in macrophages or DCs. Instead, they reveal that induction of siglec-E by LPS can modulate the phenotype of macrophages, the functional significance of which is currently unclear.
2018-02-09 | PXD008406 | Pride
Project description:The inflammatory mediator IL6 induced by LPS, which signals via TLR4, has been shown to feedback and augment TLR4 signaling when over-produced in LPS hypersensitive gp130F/F mice. The identity of the LPS/TLR4 responsive inflammatory signaling pathways and gene networks which are modulated by IL6 are unknown. Therefore, to understand the molecular consequences of gp130 hyperactivity in non-haemopoietic tissue on LPS-induced systemic inflammation, global gene expression profiling of livers was performed.
2011-05-17 | GSE29311 | GEO
Project description:Pairwise comparison of expression of alternate splicing in the Tlr4 pathway using custom designed Combimatix oligonucleotide arrays. Bone marrow derived macrophages (BMMs) from C57Bl6/J mice (6 wks male) exposed to LPS (10ng/ml) for 7hrs. Keywords: Response to LPS
2007-01-15 | GSE4044 | GEO
Project description:The experiment was designed to determine the gene expression changes cultured brown adipocytes in response to the inflammatory stimulus of LPS treatment. Both wild type and TLR4 knockout cells were applied to enable assessment of the contribution of TLR4 to the response.
2024-03-21 | E-MTAB-12834 | biostudies-arrayexpress