ABSTRACT: Comparison of gene expression by sheep and human blood stimulated with the TLR4 agonists lipopolysaccharide and monophosphoryl lipid A [human]
Project description:Comparison of gene expression by sheep and human blood stimulated with the TLR4 agonists lipopolysaccharide and monophosphoryl lipid A [sheep]
Project description:Comparison of gene expression by sheep and human blood stimulated with the TLR4 agonists lipopolysaccharide and monophosphoryl lipid A
Project description:An unresolved issue in immunology is the extent to which inflammatory effects are needed for robust T cell responses. In this study, mice were immunized by iv injection using either high toxicity lipopolysaccharide (LPS) or low toxicity monophosphoryl lipid A (MPL) as adjuvant. Six hours after iv immunization, whole spleens were harvested and gene expression was measured in unfractionated splenic populations of cells. The analysis indicated that the low toxicity adjuvanticity of MPL was associated with TLR4-mediated signaling that was biased to the TRIF branch of TLR4, while LPS generated balanced MyD88 and TRIF-associated outcomes. Keywords: Treatment comparison
Project description:Vertebrates differ greatly in responses to pro-inflammatory agonists such as bacterial lipopolysaccharide (LPS), complicating use of animal models to study human sepsis or inflammatory disorders. We compared transcriptomes of resting and LPS-exposed blood from rabbit, pig, sheep, cow, chimpanzee, human, mice, rats, baboon, and rhesus.
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:Odontoblasts and fibroblasts are suspected to influence the innate immune response triggered in the dental pulp by micro-organisms that progressively invade the human tooth during the carious process. To determine whether they differ in their responses to oral pathogens, we performed a systematic comparative analysis of odontoblast-like cell and pulp fibroblast responses to TLR2, TLR3 and TLR4 specific agonists (lipoteichoic acid [LTA], double-stranded RNA and lipopolysaccharide [LPS], respectively). Cells responded to these agonists by differential up-regulation of chemokine gene expression. CXCL2 and CXCL10 were thus increased by LTA only in odontoblast-like cells, while LPS increased CCL7, CCL26 and CXCL11 only in fibroblasts. These data suggest that odontoblasts and pulp fibroblasts differ in their innate immune responses to oral micro-organisms that invade the pulp tissue. Keywords: cell type comparaison Dental pulp fibroblasts and Odontoblast-like cells stimulated with lipopolysaccharide, ipoteichoic acid or poly(I:C), or unstimulated. Triplicates.
Project description:An unresolved issue in immunology is the extent to which inflammatory effects are needed for robust T cell responses. In this study, mice were immunized by iv injection using either high toxicity lipopolysaccharide (LPS) or low toxicity monophosphoryl lipid A (MPL) as adjuvant. Six hours after iv immunization, whole spleens were harvested and gene expression was measured in unfractionated splenic populations of cells. The analysis indicated that the low toxicity adjuvanticity of MPL was associated with TLR4-mediated signaling that was biased to the TRIF branch of TLR4, while LPS generated balanced MyD88 and TRIF-associated outcomes. Experiment Overall Design: B6.SJL mice adoptively transferred with T cells from B6.OTI and OTII transgenic TCR transgenic were immunized via intravenous injection with ova peptides alone ("Ova"), or with LPS ("OvaLPS") or MPL as adjuvant ("OvaMPL"). Six hours after immunization, the mice were euthanized by cervical dislocation, the spleens were removed and immediately lysed in guanidium chloride, and kept frozen until being used to extract total cellular RNA. Three mice each were given the indicated treatments, with independent processing and analysis of nine samples total.
Project description:These microarrays were performed for use in a genome-wide scan for LPS-regulated genes in human monocyte-derived macrophages, in order to construct a list of LPS-regulated genes for detailed interrogation on custom microarrays (see GSE19482 for custom array analysis). Human monocyte-derived macrophages (HMDM) were stimulated with the TLR4 agonist, lipopolysaccharide, over a time course (0, 0.5, 2, 6, 24h) and analysed in biological duplicate (each of which represents a pool of two independent blood donors), in total representing 4 macrophage preparations from independent blood donors, by commercial Illumina microarray.
Project description:Lung-resident and circulatory lymphoid, myeloid, and stromal cells, expressing various pattern recognition receptors (PRRs), detect pathogen and danger-associated molecular patterns (PAMPs/DAMPs), and defend against respiratory pathogens and injuries. Here, we report the early responses of murine lungs to nanoparticle-delivered PAMPs, specifically the RIG-I agonist poly-U/UC (PUUC), with or without the TLR4 agonist monophosphoryl lipid A (MPLA). Using cellular indexing of transcriptomes and epitopes by sequencing (CITE-seq), we characterized the responses at 4 and 24 hours after intranasal administration. Within 4 hours, ribosome-associated transcripts decreased in both stromal and immune cells, followed by widespread interferon-stimulated gene (ISG) expression. Using RNA velocity, we show that lung-neutrophils dynamically regulate the synthesis of cytokines like CXCL-10, IL-1α, and IL-1β. Co-delivery of MPLA and PUUC increased chemokine synthesis and upregulated antimicrobial binding proteins targeting iron, manganese, and zinc in many cell types, including fibroblasts, endothelial cells, and epithelial cells. Overall, our results elucidate the early PAMP-induced cellular responses in the lung and demonstrate that stimulation of the RIG-I pathway, with or without TLR4 agonists, induces a ubiquitous microbial defense state in lung stromal and immune cells. Nanoparticle-delivered combination PAMPs may have applications in intranasal antiviral and antimicrobial therapies and prophylaxis.
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.