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 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 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 SamplesHigh fat diets are known to be a risk factor for prostate cancer. In this study, we investigated the effect of high fat diet on mouse prostate gene expression. C57BL/6J mice were fed either a control or high fat diet for 12 weeks. Microarray analyses were performed on mouse ventral prostate (VP) and dorsolateral prostate (DLP), followed by canonical pathway analysis and regulatory network identification. mRNA changes were confirmed by real time PCR. Approximately 2,125, and 1,194 genes responded significantly to the high fat diet in VP, DLP, respectively. Pathways and networks related to oxidative stress, glutathione metabolism, NRF-mediated oxidative stress response and NF-kappaB were all differentially regulated by high fat diet. GPx3 mRNA levels were decreased by approximately 2-fold by high fat diet in all 3 prostate lobes. In human non-transformed prostate cells (PrSC, PrEC and BPH-1), cholesterol loading decreased GPx3 expression, and increased H2O2 levels of culture medium. Troglitazone increased GPx3 expression in 3 normal prostate cells, and decreased H2O2 levels. In addition, troglitazone attenuated cholesterol-induced H2O2 increase. Tissue from prostate cancer biopsies had decreased GPx3 mRNA and its level was inversely related to the Gleason score.
High fat diet reduces the expression of glutathione peroxidase 3 in mouse prostate.
No sample metadata fields
View SamplesSickle cell transcriptome was analyzed using whole blood clinical specimens on the Affymetrix Human Exon 1.0 ST arrays and Illuminas deep sequencing technologies. Data analysis indicated a strong concordance (R=0.64) between exon array and RNA-seq in both gene level and exon level expression of transcripts. The magnitude of fold changes in the expression levels for the differentially expressed genes (p<0.05) was found to be higher in RNA-seq than microarrays. However, the arrays outperformed the sequencing technology in the detection of low abundant transcripts. In addition to examining the expression level changes of transcripts, RNA-seq technology was able to identify sequence variation in the expressed transcripts. We also demonstrate herein the ability of RNA-seq technology to discover novel expression outside of the annotated genes.
A systematic comparison and evaluation of high density exon arrays and RNA-seq technology used to unravel the peripheral blood transcriptome of sickle cell disease.
Specimen part, Disease
View SamplesB19V NS1 is known to be cytotoxic and involved in the pathogenesis of B19V infection. Our previous data demonstrated that NS1 impaired the cell-cycle progression of the CD36+ EPCs by inducing a stable G2 arrest. Microarray analysis was used to identify genes whose expressions were associated with the NS1-induced G2 arrest. A total of 1045 genes displayed a more than 1.5-fold differential expression in the NS1-transduced cells. Out of 1045 differentially expressed genes, 177 were involved in cell-cycle regulation and 51 were involved in the regulation of cell differentiation.
Human parvovirus B19 causes cell cycle arrest of human erythroid progenitors via deregulation of the E2F family of transcription factors.
Specimen part
View SamplesIn sickle cell disease, ischemia-reperfusion injury and intravascular hemolysis produce endothelial dysfunction and vasculopathy characterized by reduced nitric oxide (NO) and arginine bioavailability. Recent functional studies of platelets in patients with sickle cell disease reveal a basally activated state, suggesting that pathological platelet activation may contribute to sickle cell disease vasculopathy. Studies were therefore undertaken to examine transcriptional signaling pathways in platelets that may be dysregulated in sickle cell disease. We demonstrate and validate here the feasibility of comparative platelet transcriptome studies on clinical samples from single donors, by the application of RNA amplification followed by microarray-based analysis of 54,000 probe sets. Data mining an existing microarray database, we identified 220 highly abundant genes in platelets and a subset of 72 relatively platelet-specific genes, defined by more than 10-fold increased expression compared to the median of other cell types in the database with amplified transcripts. The highly abundant platelet transcripts found in the current study included 82% or 70% of platelet abundant genes identified in two previous gene expression studies on non-amplified mRNA from pooled or apheresis samples, respectively. On comparing the platelet gene expression profiles in 18 patients with sickle cell disease in steady state to 12 African American controls, at a 3-fold cut-off and 5% false discovery rate, we identified ~100 differentially expressed genes, including multiple genes involved in arginine metabolism and redox homeostasis. Further characterization of these pathways using real time PCR and biochemical assays revealed increased arginase II expression and activity and decreased platelet polyamine levels. These studies suggest a potential pathogenic role for platelet arginase and altered arginine and polyamine metabolism in sickle cell disease and provide a novel framework for the study of disease-specific platelet biology.
Amplified expression profiling of platelet transcriptome reveals changes in arginine metabolic pathways in patients with sickle cell disease.
Specimen part
View SamplesExpression profiling using a defined set of iron regulated genes identifies co-regulation of genes and pathways related to inflammatory cytokines
Iron, inflammation, and early death in adults with sickle cell disease.
Specimen part, Disease
View Samples