Immunosuppressive inflammation driven by LPS/TLR4 signalling in hepatocellular carcinoma with low immune cell infiltration
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA1044414 | ENA |
REPOSITORIES: ENA
Similar Datasets
Project description:Non-inflamed liver tumors (i.e. immunologically silent and desert phenotype) account for two-thirds of hepatocellular carcinomas (HCC) and represent a major challenge for immune-based cancer therapies. Elucidating the factors behind the lack of T cell response would enable us to define an appropriate therapy to induce antitumor immunity based on tumor immunobiology. We applied unsupervised machine learning to the transcriptome of a rigorously selected set of non- or poorly infiltrated HCC, identified independent modular components and explored their characteristics through gene enrichment analysis and integration of molecular, cytometric, immunohistochemical and clinicopathological data. Here we demonstrate that non-/poorly infiltrated HCC (referred to as cold HCC) exhibits intricate, multi-layered mechanisms by which tumors evade the immune response. These include the recruitment of immunosuppres-sive myeloid cells into the tumor microenvironment (TME) in relation to tumor richness in Gram-negative bacterial lipopolysaccharide (LPS) and activation of the LPS/TLR4 signaling pathway. LPS-containing cold HCCs undergo immunosuppressive inflammation, likely via activation of the EGFR, LPS/TLR4 and NFKB signaling pathways. This is associated with increased expression of the checkpoint inhibitor TIM3 and its ligand, galectin 9 (Gal9). All the immune evasion factors detected in cold HCC are also at play in infiltrated HCC, suggesting in the latter the presence of TME regulatory signals opposing them. This study highlights mechanisms of immune tolerance in non-infiltrated HCC and supports the role of tumor ex-trinsic mechanisms in regulating tumor immunity in HCC.
2024-11-20 | GSE248516 | 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:TLR4 signaling of LPS chemotypes
| PRJNA1054506 | ENA
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: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:In endothelial cells (ECs), stimulation of Toll-like receptor 4 (TLR4) by the endotoxin lipopolysaccharide (LPS) induces the release of diverse pro-inflammatory mediators beneficial in controlling bacterial infections. However, their systemic secretion is a main driver of sepsis and chronic inflammatory diseases. Since distinct and rapid TLR4 signaling induction is difficult to achieve by LPS due to its poorly controllable binding and non-specific affinity to other surface molecules and receptors, we engineered new light-oxygen-voltage-sensing (LOV) domain-based optogenetic endothelial cell lines (opto-TLR4-LOV LEC and opto-TLR4-LOV HUVEC) that allow precise temporal and reversible activation of TLR4 signaling pathways. Using quantitative mass spectrometry, RT-qPCR and Western Blot analysis, we show that pro-inflammatory proteins were not only expressed differently, but also had a different time course when the cells were stimulated with light or LPS. Additional functional assays demonstrated that light induction promoted chemotaxis of THP-1 cells, disruption of the EC-monolayer and transmigration. In contrast, ECs incorporating a truncated version of the TLR4 extracellular domain (opto-TLR4 ΔECD2-LOV LEC) revealed high basal activity with fast exploitation of cell signaling system upon illumination. We conclude that the established optogenetic cell lines are well suited to induce rapid and precise photoactivation of TLR4, allowing receptor-specific studies.
2023-05-10 | PXD038764 | 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. The mouse 22K compugen oligo array from the Adelaide Microarray Facility was used to investigate the effect of LPS treatment on the livers of wildtype and gp130F/F mutant mice. Livers of both wildtype mice and gp130F/F mice at 6hr post LPS injection and also control livers wer collected. Each experimental group had 3 independant mice. In total 12 arrays were performed with a total of three biological replicates. A common reference design was used for this experiment. RNA extracted from eight pooled 17.5dpc C57BL/6 mouse embryos was used as the reference sample. 6 wildytpe mice and 6 gp130F/F mice were used in this study, with 3 mice of each genotype treated with LPS.
2011-05-17 | E-GEOD-29311 | biostudies-arrayexpress
Project description:A cyanobacterial LPS antagonist prevents endotoxin shock and blocks sustained TLR4 stimulation required for cytokine expression. We report the identification and biologic characterization of an LPS-like molecule extracted from the cyanobacterium Oscillatoria Planktothrix FP1 (CyP). Keywords: different ligands
2006-07-27 | GSE4748 | GEO