Time course study of the response to LPS targeting the pig immune response gene networks
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ABSTRACT:
ORGANISM(S): Sus scrofa
PROVIDER: GSE107487 | GEO | 2017/11/30
SECONDARY ACCESSION(S): PRJNA420347
REPOSITORIES: GEO
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Project description:Lipopolysaccharides (LPS) are found in the outer membrane of Gram-negative bacteria. The intraperitoneal (i.p.) application of LPS into mice represents a frequently applied experimental model to induce hepatic and systemic inflammation.
2021-06-30 | GSE166488 | GEO
Project description:In order to understand the appropriate use of potentially beneficial Gram positive microbes through their introduction in the gut microbiome, it is necessary to understand the influence of individual bacteria on the host response system at a cellular level. In the present study we showed that lipopolysaccharide (LPS), flagellated Gram negative bacteria, potentially beneficial Gram positive bacteria and yeast interact differently with human intestinal enterocytes (IEC) with a custom-designed expression microarray evaluating 17 specific host-response pathways. Only, LPS and flagellated Gram negative bacteria induced inflammatory response, while a subset of Gram positive microbes had anti-inflammatory potential. The main outcome from the study was the differential regulation of the central MAPK signaling pathway by these Gram positive microbes versus commensal/pathogenic Gram negative bacteria. The microarray was efficient to highlight the impact of individual bacteria on IEC response, but q-RT-PCR validation demonstrated some underestimation for down regulated genes by the microarray. This Immune Array will allow us to better understand the mechanisms underlying pathogen-induced host immune responses, aid in the selection potentially probiotic microbes and perhaps select biomarkers for future clinical studies.
2011-12-31 | GSE31394 | GEO
Project description:In order to understand the appropriate use of potentially beneficial Gram positive microbes through their introduction in the gut microbiome, it is necessary to understand the influence of individual bacteria on the host response system at a cellular level. In the present study we showed that lipopolysaccharide (LPS), flagellated Gram negative bacteria, potentially beneficial Gram positive bacteria and yeast interact differently with human intestinal enterocytes (IEC) with a custom-designed expression microarray evaluating 17 specific host-response pathways. Only, LPS and flagellated Gram negative bacteria induced inflammatory response, while a subset of Gram positive microbes had anti-inflammatory potential. The main outcome from the study was the differential regulation of the central MAPK signaling pathway by these Gram positive microbes versus commensal/pathogenic Gram negative bacteria. The microarray was efficient to highlight the impact of individual bacteria on IEC response, but q-RT-PCR validation demonstrated some underestimation for down regulated genes by the microarray. This Immune Array will allow us to better understand the mechanisms underlying pathogen-induced host immune responses, aid in the selection potentially probiotic microbes and perhaps select biomarkers for future clinical studies. In this study, human immune response was assessed by stimulating HT-29 intestinal epithelial cells (IEC) with different microorganisms (or LPS) individually. For each of the 12 different treatments, between 4 and 8 biological replicates were performed, analyzed with dye-swaps and hybridized against control or untreated cells. Genes that were showing a 1.3 mRNA transcript abundance fold change and a P-value below 0.05 were considered to be differentially expressed.
2011-12-31 | E-GEOD-31394 | biostudies-arrayexpress
Project description:Lipopolysaccharides (LPS) can lead to a lethal endotoxemia, which is a systemic inflammatory response syndrome (SIRS) characterized by a systemic release of cytokines, such as TNF. Endotoxemia is studied intensely, as a model system of gram-negative infections. LPS- as well as TNF-induced SIRS involve a strong induction of pro-inflammatory genes. In this study we investigate the response of the intestinal epithelium cells (IECs) ot LPS and may produce pro-inflammatory cytokines or suffer cell death.
2020-03-20 | GSE139903 | GEO
Project description:lpsB encodes a glycosyltransferase involved in lipopolysaccharide (LPS) synthesis. LPS is a major component of the Gram-negative bacterial outer membranes. We used custom-made Affymetrix A. baumannii strain ATCC 17978 derived GeneChips to compare the gene expression properties of wild type and isogenic lpsB mutant cells. Two mutants were evaluated; A. baumannii strain 5A7 is a ATCC 17978 derivative harboring a transposon (Tn5) within lpsB (A1S_0430 locus); A. baumannii strain containing a deletion of lpsB (A1S_0430).
2012-12-01 | GSE40771 | GEO
Project description:<p>Ralstonia solanacearum, one of the most destructive crop pathogens worldwide, causes bacterial wilt disease in a wide range of host plants. The major component of the outer membrane of Gram-negative bacteria, lipopolysaccharides (LPS), has been shown to function as elicitors of plant defense leading to the activation of signaling and defense pathways in several plant species. LPS from a R. solanacearum strain virulent on tomato (LPSR. sol.), were purified, chemically characterized and structurally elucidated. The lipid A moiety consisted of tetra- to hexa-acylated bis-phosphorylated disaccharide backbone, also decorated by aminoarabinose residues in minor species, while the O-polysaccharide chain consisted of either linear tetrasaccharide or branched pentasaccharide repeating units containing alpha-L-rhamnose, N-acetyl-beta-Dglucosamine and beta-L-xylose. These properties might be associated with the evasion of host surveillance, aiding the establishment of the infection. Using untargeted metabolomics, the effect of LPSR. sol. elicitation on the metabolome of Solanum lycopersicum leaves was investigated across three incubation time intervals with the application of UHPLC-MS for metabolic profiling. The results revealed the production of oxylipins, e.g., trihydroxy octadecenoic acid and trihydroxy octadecadienoic acid, as well as several hydroxycinnamic acid amide derivatives, e.g., coumaroyl tyramine and feruloyl tyramine, as phytochemicals that exhibit a positive correlation to LPSR. sol. treatment. Although the chemical properties of these metabolite classes have been studied, the functional roles of these compounds have not been fully elucidated. Overall, the results suggest that the features of the LPSR. sol. chemotype aid in limiting or attenuating the full deployment of small molecular host defenses and contribute to the understanding of the perturbation and reprogramming of host metabolism during biotic immune responses.</p>
2023-08-08 | MTBLS7324 | MetaboLights
Project description:A promising but yet clinically unexploited antibiotic target in difficult-to-treat Gram-negative bacteria is LpxC, the key enzyme in the biosynthesis of lipopolysaccharides (LPS), which are the major constituents of the outer membrane. To gain insights into the mode of action of five different LpxC inhibitors, we conducted a comparative phenotypic and proteomic analysis. All five compounds bound to purified LpxC from Escherichia coli. Treatment of E. coli with these compounds changed the cell shape and stabilized LpxC indicating that the inhibitor-bound enzyme is not degraded by the FtsH protease. LpxC inhibition sensitized E. coli to the cell wall antibiotic vancomycin, which typically does not cross the outer membrane. Four of the five compounds led to an accumulation of lyso-PE, a cleavage product of phosphatidylethanolamine (PE), generated by the phospholipase PldA. The combined results suggested an imbalance in phospholipid (PL) and LPS biosynthesis, which was corroborated by the global proteome response to treatment with the LpxC inhibitors. Apart from LpxC itself, FabA and FabB responsible for the biosynthesis of unsaturated fatty acids were consistently upregulated. Our work also shows that antibiotics targeting the same enzyme do not necessarily elicit identical cellular responses. Compound-specific marker proteins belonged to different functional categories, like stress responses, nucleotide or amino acid metabolism and quorum sensing. These findings provide new insights into common and distinct cellular defense mechanisms against LpxC inhibition. Moreover, they support a delicate balance between LPS and PL biosynthesis with great potential as point of attack for antimicrobial intervention.
2024-06-16 | PXD043195 | Pride
Project description:Lipopolysaccharide (LPS) resides in the outer membrane (OM) of Gram-negative bacteria where it is responsible for barrier function and immune modulation. LPS is the target of polymyxins, last-resort antibiotics whose clinical use is threatened by increasing resistance. Steps in LPS biogenesis are known, but how LPS biosynthesis and transport to the OM is coordinated remains poorly understood. Here, we find that depletion of the Escherichia coli inner membrane protein PbgA attenuates pathogenesis and produces defects in the OM. Structural analysis of PbgA identifies an enzyme superfamily known to modify the envelopes of Gram-positive and Gram-negative bacteria; however, PbgA reveals a defunct hydrolase-active site, a distinctive architecture, and an unprecedented lipid A-binding motif along the periplasmic leaflet of the inner membrane. Unlike canonical lipid-binding proteins, PbgA achieves LPS coordination primarily through backbone-mediated interactions. Offensive mutations within the lipid A-binding motif disrupt the OM barrier, suggesting that LPS perception by PbgA plays a key role in maintaining OM homeostasis. PbgA-derived synthetic peptides selectively bind to LPS in vitro and inhibit the growth of diverse Gram-negative bacterial species, including polymyxin-resistant strains. Our studies uncover an essential pseudo-hydrolase with an unexpected link to OM biogenesis, highlight a new structural paradigm in selective lipid recognition, and provide important templates for future antibiotic discovery.
2019-05-08 | MSV000083754 | MassIVE
Project description:Mechanisms to control the immune response are important to pathogen evasion and host defense. Gram-negative bacteria are common pathogens that can activate host immune responses through their outer membrane component, lipopolysaccharide (LPS). Macrophages activated by LPS induce cell signals that promote hypoxic metabolism, phagocytosis, and antigen presentation. Nicotinamide (NAM) is a vitamin B3 derivative and precursor in the formation of nicotinamide adenine dinucleotide (NAD), which is a required co-factor in cellular function. In this study, treatment of human monocyte derived macrophages with NAM antagonized LPS-induced responses by altering the expression of ubiquitin genes, increasing HIF-1alpha and p65/RelA ubiquitination, decreasing p65/RelA acetylation and promoting the formation of the proteasome. NAM also elevated intracellular NAD levels and altered the genetic expression of sirtuins and poly(ADP-ribose) polymerases. These NAM responses highlight post-translational events in regulating the host response to pathogens and identify the ubiquitome as a target in pathogen evasion and host defense.
2023-05-01 | GSE188206 | GEO
Project description:Objectives How HLA-B27 contributes towards arthritis susceptibility is still unclear, but effects on the response to bacteria unrelated to the classical antigen presenting role of B27 have been suggested. This study investigated whether HLA-B27 modulates the innate response to LPS, a component shared between all Gram –ve bacteria that can trigger reactive arthritis. Methods Pools of U937 transfectants expressing either HLA-B27, HLA-A2, or the expression plasmid alone were differentiated with PMA and stimulated with LPS. Supernatants were analysed for TNF-alpha secretion and the gene expression profiles of unstimulated and LPS stimulated cells were determined by microarray analysis. Changes in gene expression that are indicative of an unfolded protein response were also analysed by quantitative PCR. Results TNF-alpha secretion, a biological marker of the inflammatory response to LPS, was not significantly different between U937-B27 and U937-control. No differences in gene expression between unstimulated U937- B27 and U937-control lines were detected. Both U937-control and U937-B27 exhibited a stereotypic response to LPS. Only 1 gene, OAS2, was differentially expressed by these cell lines, and this was confirmed by quantitative PCR. Analysis of XBP-1 splicing suggested that a small increase in the unfolded protein response is induced following LPS stimulation, but this increase was seen in all transfectants. Conclusions The expression of B27 does not profoundly alter gene expression following LPS stimulation. Therefore, additional signals, such as those provided by cytokines or intracellular infection, may be required to reveal any influence of B27 expression on the inflammatory response. Keywords: antigen response
2006-04-10 | GSE4579 | GEO