Project description:We have measured the presence of histone H3 and its modifications H3K4me3, H3K27me3 and AcH3 in the promoters of three different cell types: monocytes and monocyte derived macrophages and dendritic cells. The measurements were performed using Nimblegen 385K RefSeq Promoters array.
Project description:In response to inflammatory stimulation, dendritic cells (DCs) have a remarkable pattern of differentiation (maturation) that exhibits specific mechanisms to control immunity. Here, we show that in response to Lipopolysaccharides (LPS), several microRNAs (miRNAs) are regulated in human monocyte-derived dendritic cells. Among these miRNAs, miR-155 is highly up-regulated during maturation. Using LNA silencing combined to microarray technology, we have identified the Toll-like receptor / interleukin-1 (TLR/IL-1) inflammatory pathway as a general target of miR-155. We further demonstrate that miR-155 directly controls the level of important signal transduction molecules. Our observations suggest, therefore, that in mature human DCs, miR-155 is part of a negative feedback loop, which down-modulates inflammatory cytokine production in response to microbial stimuli. We devised a strategy to functionally inhibit the mature form of miR-155 with the aim of identifying the signaling pathways controlled by miR-155 during DC maturation. A LNA-modified oligonucleotide, specifically designed for miR-155 knockdown (anti-miR-155 LNA) was introduced in moDCs by nucleofection prior LPS stimulation. 24h after transfection, a reduction in miR-155 levels of 8- and 32-fold was observed by qPCR in immature and mature moDCs respectively. A comparative microarray analysis (Affymetrix U133 2.0 chip) was performed among miR-155 silenced (anti-miR-155 LNA) and control transfected (scramble LNA) moDCs, exposed or not to LPS. Thus, four samples were totally analyzed. As expected from the limited expression of miR-155 in non-activated DCs, little variation in mRNA expression (177 probe sets differentially expressed employing a cut-off of 1.5) was detected upon miR-155 silencing. Conversely, in LPS-activated cells many mRNAs (1324 probe sets, 770 up-regulated and 554 down-regulated) were affected by miR-155 inhibition.
Project description:Dendritic cells (DCs) are the sentinels of the mammalian immune system and they undergo a complex maturation process mediated by activation upon pathogen detection. Recent studies described the analysis of activated DCs by transcriptional profiling, but translation regulation was never taken in account. Therefore, the nature of the mRNAs being translated at various stages of DC activation was determined with the help of translational profiling, which is the sucrose gradient fractionation of polysomal-bound mRNAs combined to microarrays analysis. Total and polysomal-bound mRNA populations were compared in immature (0h) and LPS-stimulated (4h and 16h) human monocyte-derived DCs with the help of Affymetrix microarrays. Biostatistical analysis indicated that 296 mRNA molecules are translationally regulated during DC-activation. The most abundant biological process among the regulated mRNAs was protein biosynthesis, indicating the existence of a negative feedback loop regulating translation. Interestingly, a cluster of 17 ribosomal proteins were part of the regulated mRNAs, indicating that translation may be fine-tuned by particular components of the translational machinery. Our observations highlight the importance of translation regulation during the immune response, and may favour the identification of novel gene clusters or protein networks relevant for immunity. Our study also provides information on the possible absence of correlation between gene expression and real protein production in DCs. To identify translationally regulated mRNA molecules, gene expression derived from the polysome-bound mRNAs was compared by Affymetrix microarrays analysis to the gene expression derived from unfractionated total mRNAs derived from whole-cell lysates, as recently described on several reports (Johannes 1999, Rajasekhar 2003, Bushell 2006, Lü 2006, Parent 2008). Polysomal RNA (P) and total RNA (T) were isolated from MoDCs generated from four different blood donors. Since three timepoints (0h, 4h and 16h) were chosen for each blood donor and RNA type, twenty-four RNA samples were totally analyzed by microarrays.
Project description:In this study, we compared human monocytes differentiated for 7 days with M-CSF and/or GM-CSF. A comparison of the different macrophage populations was made using microarray profiling. Threshold: 1.0 . Logbase: 2 . Technology: Agilent.SingleColor.14850. Normalization: Shift to 75 percentile . Baseline Transformation: median of all samples . FlagSettings:. Feature is not Uniform:A. Feature is a population outlier:A. Feature is Saturated:A. Feature is not above background:M. Feature is not positive and significant:M.
Project description:miRNA expression profiling of human monocyte-derived dendritic cells (moDCs) during maturation. Immature, 4h and 16h LPS-activated moDCs were used. In this study were analysed 2 biological samples of RNA extracted from 4h-post LPS stimulation moDCs and 2 bfrom 16h-post LPS stimulation. The RNA from 0h-post LPS stimulation were used as reference sample. Were also performed dye-swaps of each biological sample as technical replicates.
Project description:We performed gene expression microarray experiments to compare the global transcriptional response induced by b-glucans and LPS with their secretomes. We identified 1683, 767 and 1447 genes with over two-fold increase or decrease in LPS-, curdlan- or GBY-stimulated macrophages, respectively. We show that both LPS and b-glucan induces significant gene expression changes in macrophages, but only b-glucans activate a robust protein secretion. The gene expression of human primary macrophage cells was measured at 6 hours after exposure the cells to 1 µg LPS or 10 µg Curdlan or 100 µg GBY (glucan from baker´s yeast), also 0-group was included. Three independent experiments were performed using three different donors for each experiment.
Project description:In order to dissect the response from different fungal cell wall components, monocyte-derived dendritic cells obtained from healthy donors were collected and either left untreated, or treated for four hours with either mannan, zymosan, curdlan, whole yeast, or yeast spores. This experiment is related to E-MTAB-1213.
Project description:In this study, we compared human monocytes treated with GM-CSF, M-CSF, dexamethosone or in combination with dexamethasone. A comparison of the different monocyte populations was made using microarray profiling.
Project description:Identification of genes differentially expressed between human monocyte-macrophages generated in the presence of either GM-CSF (termed M1) or M-CSF (termed M2) Human peripheral blood monocytes from three independent healthy donors (#1, #2 and #3) were isolated by anti-CD14-labeled magnetic microbeads. CD14+ monocytes were cultured for 7 days in RPMI 10% FCS containing either GM-CSF or M-CSF. Total RNA from each condition was extracted and purified using the RNeasy kit (Qiagen). Labelled RNA was used as hybridization probes on human Codelink Whole genome Bioarray. All experimental procedures were performed following manufacturer instructions. Microarrays were scanned with a GenePix 4000B (Axon Instruments) scanner. Scanned images and raw data were processed using the Codelink Expression Software.