Metabolomics,Unknown,Transcriptomics,Genomics,Proteomics

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PBMC IFNg Dose Reponse

ABSTRACT: PBMC response to three concentrations of IFNg (0.006, 0.6 and 60 pM) from 0-12h. Abstract: Background Interferons are key modulators of the immune system, and are central to the control of many diseases. The response of immune cells to stimuli in complex populations is the product of direct and indirect effects, homotypic and heterotypic cell interactions. Dissecting the global transcriptional profiles of immune cell populations may provide insights into this regulatory interplay. The host transcriptional response may also be useful in discriminating between disease states, and in understanding pathophysiology. The transcriptional programs of cell populations in health therefore provide a paradigm for deconvoluting disease-associated gene expression profiles. Results: We used human cDNA microarrays to (1) compare the gene expression programs in human peripheral blood mononuclear cells (PBMCs) elicited by 6 major mediators of the immune response: interferons a, b, w and g, IL12 and TNFa; and (2) characterise the transcriptional responses of purified immune cell populations (CD4+ and CD8+ T cells, B cells, NK cells and monocytes) to IFNg stimulation. We defined a highly stereotyped response to type I interferons, while responses to IFNg and IL12 were largely restricted to a subset of type I interferon-inducible genes. TNFa stimulation resulted in a distinct pattern of gene expression. Cell type-specific transcriptional programs were identified, highlighting the pronounced response of monocytes to IFNg, and emergent properties associated with IFN-mediated activation of mixed cell populations. Conclusions: This information provides a detailed view of cellular activation by immune mediators, and contributes an interpretive framework for the detection and definition of host immune responses in a variety of disease settings. PBMC extraction and stimulation Human primary peripheral blood mononuclear cells (PBMCs) were purified from whole blood of healthy donors using Ficoll-Paque PLUS (GE Healthcare) according to manufacturers instructions. PBMCs were incubated at 1.5-2.0 x 106 cells/well for 24 h before stimulation in RPMI 1640 medium supplemented with 10% heat-inactivated foetal calf serum and 2 mM L-glutamine (Invitrogen) at 37C, 5% CO2. Cells were treated with 0.006 pM, 0.6 pM or 60 pM recombinant IFNg (R&D Systems), and sampled at time intervals from 0.5 h to 12 h after stimulation. Additionally, cells were treated with 0.1 % BSA/PBS alone and used for untreated (mock) control time courses. RNA extraction and amplification Total RNA was extracted in TRIzol LS (Invitrogen) followed by standard chloroform purification and isopropanol precipitation. RNA was resuspended in RNase-free water, quantitated on the NanoDrop ND-1000 spectrophotometer (NanoDrop Technologies) and stored at -80C. 500 ng total RNA was amplified using the MessageAmp modified Eberwine linear amplification procedure (Applied Biosystems). All samples to be compared were extracted and amplified together. Microarray analysis 4 ug amplified RNA was labelled with Cy5-dUTP (GE Healthcare) and combined with 3 ug of Cy3-labelled reference cDNA derived from a pool of RNA derived from a panel of 11 human cell lines (Stratagene Universal Human Reference RNA). The samples were washed and concentrated using MinElute columns (Qiagen) and competitively hybridised to custom printed cDNA microarrays containing 37,632 elements for approximately 18,000 unique human genes. The hybridised slides were scanned using a GenePix 4000A microarray scanner (Axon Instruments). Comparative spot intensities were calculated from the images, and areas of poor quality excluded from further analysis using GenePix Pro 6.0 (Axon Instruments). Data were deposited in the Stanford Microarray Database. Analysis was restricted to cDNA elements with a regression correlation of > 0.6, fluorescence intensities of > 2.5 fold signal/background in Cy3 or Cy5 channels and a minimum signal intensity of > 100 in both channels for at least 80% of the arrays. The expression ratios were normalised for array variation, and the data zero-transformed using a custom-designed Microsoft Excel macro (C. Liu, Stanford). The statistical package SAM (Significance Analysis of Microarrays, version 1.15) was used to identify genes significantly differentially expressed in the normalised data sets by pairwise comparison with a minimum 2 fold cutoff at a false discovery rate of < 1% of the median. The transformed datasets were then hierarchically clustered using Cluster 2.11 and the results displayed using Treeview 1.60. A dose response design type examines the relationship between the size of the administered dose and the extent of the response of the organism(s).

ORGANISM(S): Homo sapiens

SUBMITTER: Simon Waddell

PROVIDER: E-GEOD-16252 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Publications

Dissecting interferon-induced transcriptional programs in human peripheral blood cells.

Waddell Simon J SJ Popper Stephen J SJ Rubins Kathleen H KH Griffiths Michael J MJ Brown Patrick O PO Levin Michael M Relman David A DA

PloS one 20100322 3

Interferons are key modulators of the immune system, and are central to the control of many diseases. The response of immune cells to stimuli in complex populations is the product of direct and indirect effects, and of homotypic and heterotypic cell interactions. Dissecting the global transcriptional profiles of immune cell populations may provide insights into this regulatory interplay. The host transcriptional response may also be useful in discriminating between disease states, and in underst ...[more]

PMID: 20339534

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Project description:To identify mRNAs associated with human PUM2 protein, we used a modified Ribonucleoprotein-ImmunoPrecipitation Microarray (RIP-Chip) approach on HeLa S3 cancer cells that express PUM2. PUM ribonucleoprotein (RNP) complexes were captured from cell-free extracts with specific anti PUM2 antibody coupled to protein A sepharose beads, and then eluted with SDS-EDTA. To control for non-specifically enriched RNAs, the same procedure was performed with beads that were not coupled with immunoprecipitating antibodies (mock samples). Total RNA was isolated from cell extracts and immunopurified samples with the mirVanaTM PARISTM kit (Ambion). RNA was quantified with a NanoDrop device (Witeg AG). Poly-adenylated RNAs were amplified in the presence of aminoallyl-UTP with Amino Allyl MessageAmp II aRNA kit (Ambion). For this purpose, 500 ng total RNA from extracts and half (50-100 ng) of the immunopurified RNAs were used for amplification. 8 ug of the amplified RNAs (aaRNA) were fluorescently labeled with NHS-monoester Cy3 and Cy5 dyes (GE HealthSciences), except for mock RNA samples, where an aaRNA amount proportional to the yield obtained from corresponding PUM affinity isolates was used.For PUM2 RIPs, we performed four biological replicates but omitted the dye swaps due to the lower aaRNA obtained after amplification (~10 ug aaRNA from PUM2 RIPs, 9 ug aaRNA from mock RIPs). The Cy3- and Cy5-labeled aaRNA samples were mixed and hybridized to human cDNA microarrays. Detailed methods for microarray experiments are available at http://cmgm.stanford.edu/pbrown/protocols/index.html. cDNA microarrays were produced by the Stanford Functional Genomic Facility and contained 43,197 human probes representing 26,524 Unigene cluster IDs (12,466 ENSEMBL annotated genes) spotted on Corning Ultra GAPS slides. Spotted cDNAs were cross-linked with 65 mJ of UV irradiation on slides, which were then post-processed for 1 hour at 42°C in pre-hybridization solution (5x SSC, 0.1% SDS, 0.1 mg/ml BSA), washed twice in 400 ml of 0.1x SSC for 5 min, dunked in 400 ml ultrapure water for 30 sec, and dried by centrifugation at 550 rpm for 5 min. Slides were used the same day. Cy3- and Cy5-labeled aaRNA probes were mixed and applied to arrays in hybridization solution (3x SSC, 20 ug poly(A) RNA [Invitrogen], 20 ug yeast tRNA [Invitrogen], 20 ug Human Cot-1 DNA [Invitrogen], 20 mM HEPES [pH 7.0] and 0.3% SDS) for 18 h at 65°C. The arrays were then washed sequentially in 400 ml of 2x SSC with 0.1% SDS, 1x SSC, and 0.2x SSC. The first wash was performed for 5 min at 65°C, the subsequent washes were performed for 5 min at RT. The arrays were dried by centrifugation and immediately scanned with an AxonScanner 4200A (Molecular Devices). Data were collected using GENEPIX 5.1 (Molecular Devices). Arrays were normalized computationally by the Stanford Microarray Database (SMD). The data were filtered for signal over background of greater than 1.5 in the channel measuring aaRNA from extract, and only features that met these criteria in > 50% of the arrays were included for further analysis. Log2 median ratios were retrieved and exported into Microsoft Excel. To identify transcripts that were specifically enriched by association with PUM2, we performed two class Significance Analysis of Microarrays (SAM) on median centered arrays. A replicate experimental design type is where a series of replicates are performed to evaluate reproducibility or as a pilot study to determine the appropriate number of replicates for a subsequent experiments. Antibody used in IP: 50 ug rabbit anti-PUMILIO 2 (Bethyl Laboratories, #300-202A) Keywords: replicate_design Computed

Dataset Information

PBMC IFNg Dose Reponse

Publications

Dissecting interferon-induced transcriptional programs in human peripheral blood cells.

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