Room temperature whole blood mRNA stabilization procedures, such as the PAX gene system, are critical for the application of transcriptional analysis to population-based clinical studies. Global transcriptome analysis of whole blood RNA using microarrays has proven to be challenging due to the high abundance of globin transcripts that constitute 70% of whole blood mRNA in the blood. This is a particular problem in patients with sickle-cell disease, secondary to the high abundance of globin-expressing nucleated red blood cells and reticulocytes in the circulation . In order to more accurately measure the steady state whole blood transcriptome in sickle-cell patients, we evaluated the efficacy of reducing globin transcripts in PAXgene stabilized RNA samples for genome-wide transcriptome analyses using oligonucleotide arrays. We demonstrate here by both microarrays and Q-PCR that the globin mRNA depletion method resulted in 55-65 fold reduction in globin transcripts in whole blood collected from healthy volunteers and sickle-cell disease patients. This led to an improvement in microarray data quality with increased detection rate of expressed genes and improved overlap with the expression signatures of isolated peripheral blood mononuclear (PBMC) preparations. The differentially modulated genes from the globin depleted samples had a higher correlation coefficient to the 112 genes identified to be significantly altered in our previous study on sickle-cell disease using PBMC preparations. Additionally, the analysis of differences between the whole blood transcriptome and PBMC transcriptome reveals important erythrocyte genes that participate in sickle-cell pathogenesis and compensation. The combination of globin mRNA reduction after whole-blood RNA stabilization represents a robust clinical research methodology for the discovery of biomarkers for hematologic diseases and in multicenter clinical trials investigating a wide range of nonhematologic disorders where fractionation of cell types is impracticable.
Characterization of whole blood gene expression profiles as a sequel to globin mRNA reduction in patients with sickle cell disease.
Specimen part, Subject
View SamplesDifferentiation of naive CD8 T cells into cytotoxic effector cells requires three distinct signals- antigen (signal 1), costimulation -B7-1 (signal 2) and cytokine, either interleukin-12 or interferon-a/b (signal 3). Interaction of naive CD8 T cells with antigen and B7-1 programs cell division and proliferation whereas the presence of cytokines- IL-12 or IFNa/b promote survival, differentiation and memory establishment. In the absence of signal 3, the cells interacting with antigen/B7-1 undergo tolerance induction. The objective of this study was to elucidate the mechanisms how the provision of signal 3 promotes differentiation and averts tolerance induction in CD8 T cells. Trichostatin A is a pharmacological agent that inhibits histone deacetylase activity, hence regulating chromatin structure and gene expression and differentiation in many cell types. Gene signature profiles of IL-12, IFNa/b and trichostatin A stimulated cells were compared to elucidate the molecular mechanisms of gene regulation.
Gene regulation and chromatin remodeling by IL-12 and type I IFN in programming for CD8 T cell effector function and memory.
Age, Specimen part, Time
View SamplesAngiogenesis is tightly regulated by both soluble growth factors and cellular interactions with the extracellular matrix (ECM). While cell adhesion via integrins has been shown to be required for growth factor signaling and downstream angiogenesis, the effects of quantitative changes in cell adhesion and spreading against the ECM remain less clear.
Decreased cell adhesion promotes angiogenesis in a Pyk2-dependent manner.
Specimen part
View SamplesIn C. elegans, ablation of germline stem cells (GSCs) extends lifespan, but also increases fat accumulation and alters lipid metabolism, raising the intriguing question of how these effects might be related. Here we show that a lack of GSCs results in a broad transcriptional reprogramming, in which the conserved detoxification regulator SKN-1/Nrf increases stress resistance, proteasome activity, and longevity. SKN-1 also activates diverse lipid metabolism genes and reduces fat storage, thereby alleviating the increased fat accumulation caused by GSC absence. Surprisingly, SKN-1 is activated by signals from this fat, which appears to derive from unconsumed yolk that was produced for reproduction. We conclude that SKN-1 plays a direct role in maintaining lipid homeostasis, in which it is activated by lipids. This SKN-1 function may explain the importance of mammalian Nrf proteins in fatty liver disease, and suggests that particular endogenous or dietary lipids might promote health through SKN-1/Nrf. Overall design: Samples were prepared from ~5,000 synchronized, L1 arrested day-one adult animals cultured at 25°C. Worms were synchronized by sodium hypochlorite (bleach) treatment, as previously described (Porta-de-la-Riva et al., 2012). Bleach solution (9 mL ddH2O; 1 mL 1 N NaOH; 4 mL Clorox bleach) was freshly prepared before each experiment. Worms were bleached for 5 minutes, washed 5x in M9, and arrested at the L1 stage at 25°C in M9 containing 10 µg/mL cholesterol. Feeding RNAi was started at the L1 stage. This approach only partially reduces skn-1 function, but allows analysis of larger samples than would be feasible with skn-1 mutants, which are sterile (Bowerman et al., 1992). Because these animals were not treated with FUdR, the WT adults contained an intact germline and eggs. As is explained in the Results section, we therefore confined our analysis to genes that were overrepresented in glp-1(ts) animals, which lack eggs and most of the germline, and established a high-confidence cutoff for genes that were upregulated by GSC absence as opposed to simply being expressed specifically in somatic tissues. RNA was extracted using the same protocol for qRT-PCR samples. Purified RNA samples were DNase treated and assigned a RIN quality score using a Bioanalyzer 2100 (Agilent Technologies, Santa Clara, CA). Only matched samples with high RIN scores were sent for sequencing. Single read 50 bp RNA sequencing with poly(A) enrichment was performed at the Dana-Farber Cancer Institute Center for Computational Biology using a HiSeq 2000 (Illumina, San Diego, CA). FASTQ output files were aligned to the WBcel235 (Feb 2014) C. elegans reference genome using STAR (Dobin et al., 2013). These files have been deposited at the Gene Expression Omnibus (GEO) with the accession number GSE63075. Samples averaged 75% mapping of sequence reads to the reference genome. Differential expression analysis was performed using a custom R and Bioconductor RNA-seq pipeline (http://bioinf.wehi.edu.au/RNAseqCaseStudy/) (Gentleman et al., 2004; Anders et al., 2013; R Core Team, 2014). Quantification of mapped reads in the aligned SAM output files was performed using featureCounts, part of the Subread package (Liao et al., 2013, 2014). We filtered out transcripts that didn't have at least one count per million reads in at least two samples. Quantile normalization and estimation of the mean-variance relationship of the log-counts was performed by voom (Law et al., 2014). Linear model fitting, empirical Bayes analysis and differential expression analysis was then conducted using limma (Smyth, 2005). To identify genes that are upregulated in a SKN-1-dependent manner by GSC loss, we sought genes for which glp-1(ts) expression was higher than WT, and for which glp-1(ts);skn-1(-) expression was reduced relative to glp-1(ts). To test for this pattern, if a gene's expression change was higher in the comparison of glp-1(ts) vs. WT and lower in the comparison of glp-1(ts);skn-1(-) vs. glp-1(ts), then we calculated the minimum (in absolute value) of the t-statistics from these two comparisons, and assessed the significance of this statistic by comparing to a null distribution derived by applying this procedure to randomly generated t-statistics. We corrected for multiple testing in this and the differential expression analysis using the false discovery rate (FDR) (Benjamini and Hochberg, 1995). Heatmaps were generated using heatmap.2 in the gplots package (Warnes et al., 2014). Functional annotations and phenotypes were obtained from Wormbase build WS246. SKN-1 transcription factor binding site analysis of hits was conducted with biomaRt, GenomicFeatures, JASPAR, MotifDb, motifStack, MotIV, and Rsamtools (Sandelin et al., 2004; Durinck et al., 2005; Durinck et al., 2009; Lawrence et al., 2013; Ou et al., 2013; Mercier and Gottardo, 2014; Shannon, 2014). JASPAR analysis was performed with the SKN-1 matrix MA0547.1 using 2 kb upstream sequences obtained from Ensembl WBcel235 (Staab et al., 2013). modENCODE SKN-1::GFP ChIP-seq analysis of hits was performed using biomaRt, ChIPpeakAnno, IRanges, and multtest (Durinck et al., 2005; Durinck et al., 2009; Gerstein et al., 2010; Zhu et al., 2010; Niu et al., 2011; Lawrence et al., 2013). SKN-1::GFP ChIP-seq peaks were generated by Michael Snyder's lab. We used the peak data generated from the first 3 larval stages: L1 (modENCODE_2622; GSE25810), L2 (modENCODE_3369), and L3 (modENCODE_3838; GSE48710). Human ortholog matching was performed using Wormbase, Ensembl, and OrthoList (Shaye and Greenwald, 2011). Gene lists were evaluated for functional classification and statistical overrepresentation with Database for Annotation, Visualization and Integrated Discovery (DAVID) version 6.7 (Dennis et al., 2003).
Lipid-mediated regulation of SKN-1/Nrf in response to germ cell absence.
Cell line, Subject
View SamplesSomatic mutation in the X-linked phosphatidylinositol glycan class A (PIG-A) gene causes glycosylphosphatidylinositol (GPI) anchor deficiency in humans with Paroxysmal Nocturnal Hemoglobinuria (PNH). Clinically, patients with PNH have intravascular hemolysis, venous thrombosis and bone marrow failure. We produced a conditional Pig-a knock-out mouse model specifically inactivating the Pig-a gene in hematopoietic cells to study the role of PIG-A deficiency in PNH pathophysiology. We used Affymetrix Mouse Genome 430 2.0 chips to investigate the gene expression pattern in the mouse model of targeted Pig-a deletion.
Phenotypic and functional characterization of a mouse model of targeted Pig-a deletion in hematopoietic cells.
No sample metadata fields
View SamplesHematopoietic differentiation is strictly regulated by complex network of transcription factors that are controlled by ligands binding to cell surface receptors. Disruptions of the intricate sequences of transcriptional activation and suppression of multiple genes cause hematological diseases, such as leukemias, myelodysplastic syndromes or myeloproliferative syndromes. From a clinical standpoint, deciphering the pattern of gene expression during hematopoiesis may help unravel disease-specific mechanisms in hematopoietic malignancies. Herein, we describe a human in vitro hematopoietic model system where lineage specific differentiation of CD34+ cells was accomplished using specific cytokines. Microarray and RNAseq based whole transcriptome and exome analysis was performed on the differentiated erythropoietic, granulopoietic and megakaryopoietic cells to delineate changes in expression of whole transcripts and exons. Analysis on the Human 1.0 ST exon arrays indicated differential expression of 172 genes (P< 0.0000001) and significant splicing of 86 genes during differentiation. Pathway analysis identified these genes to be involved in Rac/RhoA signaling, Wnt/B-catenin signaling and alanine/aspartate metabolism. Comparison of the microarray data to next generation RNAseq analysis during erythroid differentiation demonstrated a high degree of correlation in gene (R= 0.72) and exon (R=0. 62) expression. Our data provides a molecular portrait of events that regulate differentiation of hematopoietic cells. Knowledge of molecular processes by which the cells acquire their cell specific fate would be beneficial in developing cell-based therapies for human diseases.
Transcriptome profiling and sequencing of differentiated human hematopoietic stem cells reveal lineage-specific expression and alternative splicing of genes.
Specimen part
View SamplesRUNX1 is a frequent target of translocations in acute myeloid leukemia whereby its DNA binding domain fuses to different epigenetic regulators. To assess how different RUNX1 fusion proteins interact with the epigenome we compared the global binding patterns and the chromatin landscape of t(8;21) and t(3;21) AML which express RUNX1-ETO and RUNX1-EVI-1, respectively. We found that differential prognosis for these types of AML is reflected in fundamental differences in gene expression, chromatin landscape, binding patterns of the fusion proteins and other transcription factors as identified by genome-wide digital footprinting in patients. As previously shown for RUNX1-ETO, knockdown of RUNX1-EVI-1 expression initiates differentiation of t(3;21) cells which is associated with up-regulation of genes vital for myeloid differentiation, including C/EBPa. Furthermore, by expressing either dominant-negative C/EBP or an inducible C/EBPa construct in t(3;21) cells we show that C/EBPa is necessary and sufficient for the differentiation response of these cells to RUNX1-EVI-1 knockdown. Overall design: RNA-seq expreiments have been used to study the chromatin landscape of t(8;21) and t(3;21) AML
RUNX1-ETO and RUNX1-EVI1 Differentially Reprogram the Chromatin Landscape in t(8;21) and t(3;21) AML.
Specimen part, Subject
View SamplesAging is associated with mitochondrial dysfunction and insulin resistance. We conducted a study to determine the role of long-term vigorous endurance exercise on age-related changes in insulin sensitivity and various indices of mitochondrial functions.
Endurance exercise as a countermeasure for aging.
No sample metadata fields
View SamplesBone marrow-derived progenitor cells are under investigation for cardiovascular repair, but may be altered by disease. We identified 82 differentially expressed genes in CD133+ cells from patients with coronary artery disease (CAD) versus controls, of which 59 were found to be up-regulated and 23 down-regulated. These genes were found to be involved in carbohydrate metabolism, cellular development and signaling, molecular transport and cell differentiation. Following completion of an exercise program, gene expression patterns resembled those of controls in 7 of 10 patients.
Transcriptional profiling of CD133(+) cells in coronary artery disease and effects of exercise on gene expression.
Specimen part, Disease, Treatment
View SamplesWe performed microarray to compare gene expression patterns of PBMC treated with rATG or hATG. Fold changes were compared using 2-way ANOVA tests for untreated, rATG- and hATG-treated PBMC. In PBMC treated with 10 ug/mL rATG, compared with untreated PBMC, 478 genes showed up-regulation, and 341 genes showed down-regulation at 24 hours using 10% FDR and 2-fold change cutoff. Immediately striking was that 10 ug/mL hATG had affected many fewer genes than did rATG: only 3 genes were up-regulated and 6 genes were down-regulated at 24 hours in hATG-treated PBMC. When we compared rATG with hATG, rATG induced up-regulation of 268 genes and down-regulation of 95 genes. These genes belong to the categories of immune response (64 genes), cytokine-cytokine receptor interaction (36 genes), regulation of cell proliferation (24 genes), cell cycle (23 genes), cell growth (8 genes), apoptosis (7 genes), and others.
Rabbit ATG but not horse ATG promotes expansion of functional CD4+CD25highFOXP3+ regulatory T cells in vitro.
No sample metadata fields
View Samples