Peripheral whole blood-based gene expression profiling has become one of the most common strategies exploited in the development of clinically relevant biomarkers. However, the ability to identify biologically meaningful conclusions from gene expression patterns in whole blood is highly problematic. First, it is difficult to know whether or not expression patterns in whole blood capture those in primary tissues. Second, if explicit steps are not taken to accommodate the extremely elevated expression levels of globin in blood then large-scale multi-probe microarray-based studies can be severely compromised. Many studies consider the use of mouse blood as a model for human blood in addition to considering blood gene expression levels as a general surrogate for gene expression levels in other tissues. We explored the effects of globin reduction on peripheral mouse blood in the detection of genes known to be expressed in human tissues. Globin reduction resulted in 1.) a significant increase in the number of probes detected (5840 944 vs 12411 1904); 2.) increased expression for 4128 probe sets compared to non-globin reduced blood (p < .001, two-fold); 3.) improved detection of genes associated with many biological pathways and diseases; and 4.) an increased ability to detect genes expressed in 27 human tissues (p < 10-4). This study suggests that although microarray-based mouse blood gene expression studies that do not consider the effects of globin are severely compromised, globin-reduced mouse whole blood gene expression studies can be used to capture the expression profiles of genes known to contribute to various human diseases.
The effects of globin on microarray-based gene expression analysis of mouse blood.
Sex, Age, Specimen part
View SamplesThis series includes the four major subtypes of pituitary adenomas and normal post-mortem pituitary tissue
Differential gene expression in pituitary adenomas by oligonucleotide array analysis.
No sample metadata fields
View SamplesWe have shown that removal of Lkb1 in chondorcytes results in enchondroma-like structure in postnatal mouse long bones. To furhter understand the role of Lkb1 in this process, we performed microarrrays to compare the transcriptional profile between control and conditional Lkb1 mutant (Col2a1-Cre; Lkb1c/c) chondrocytes.
Lkb1/Stk11 regulation of mTOR signaling controls the transition of chondrocyte fates and suppresses skeletal tumor formation.
Specimen part
View SamplesAllergen exposure induces the airway epithelium to produce chemoattractants, proallergic interleukins, matrix-modifying proteins, and proteins that influence the growth and activation state of airway structural cells. These proteins, in turn, contribute to the influx of inflammatory cells and changes in structure that characterize the asthmatic airway. To use the response of the airway epithelium to allergen to identify genes not previously associated with allergic responses, we compared gene expression in cytokeratin-positive cells before and after segmental allergen challenge. After challenge with concentrations of allergen in the clinically relevant range, 755 (6%) of the detectable sequences had geometric mean fold-changes in expression, with 95% confidence intervals that excluded unity. Using a prospectively defined conservative filtering algorithm, we identified 141 sequences as upregulated and eight as downregulated, with confirmation by conventional polymerase chain reaction in all 10 sequences studied. Using this approach, we identified asthma-associated sequences including interleukin (IL-)-3, IL-4, and IL-5 receptor subunits, the p65 component of nuclear factor-kappaB, and lipocortin. The genomic response of the human airway to concentrations of allergen in the clinically relevant range involves a greater number of genes than previously recognized, including many not previously associated with asthma that are differentially expressed after airway allergen exposure.
Effects of allergen challenge on airway epithelial cell gene expression.
No sample metadata fields
View SamplesBiofilm formation and type III secretion have been shown to be reciprocally regulated in P. aeruginosa, and it has been suggested that factors related to acute infection may be incompatible
Biofilms and type III secretion are not mutually exclusive in Pseudomonas aeruginosa.
No sample metadata fields
View SamplesBackground: Moderate hypothermia (32oC for 12 72 hours) has therapeutic applications, but the mechanisms by which it affects cellular function are unclear. We tested the hypothesis that moderate hypothermia produces broad changes in gene expression by human cells at the level of mRNA.
Effect of moderate hypothermia on gene expression by THP-1 cells: a DNA microarray study.
No sample metadata fields
View SamplesThe molecular mechanisms regulating endothelial to hematopoietic transition (EHT) of hemogenic endothelium (HE) are poorly understood. Here we profile the transcriptional changes resulting from SOX7 overexpression during EHT Overall design: FLK1+ cells were sorted from day 3.5 iSox7 EBs and cultured in liquid blast media for 48hours. Dox was added for 6, 12 and 24 hours to induce SOX7 expression, before samples were harvested for RNAseq.
Interplay between SOX7 and RUNX1 regulates hemogenic endothelial fate in the yolk sac.
Specimen part, Treatment, Subject, Time
View SamplesNon-steroidal anti-inflammatory drugs (NSAIDs) are used extensively as therapeutic agents, despite their well-documented gastrointestinal (GI) toxicity. Presently, the mechanisms responsible for NSAID-associated GI damage are incompletely understood. In this study, we used Microarray analysis to generate a novel hypothesis about cellular mechanisms that underlie the GI toxicity of NSAIDs. Monolayers of intestinal epithelial
Drug-induced alterations to gene and protein expression in intestinal epithelial cell 6 cells suggest a role for calpains in the gastrointestinal toxicity of nonsteroidal anti-inflammatory agents.
Specimen part
View SamplesGonadotrope or null cell pituitary tumors present clinically with signs of hypogonadism and hypopituitarism, together with visual disturbances due to mass effects. Since there are no medical therapies, surgery and/or radiation are the only therapeutic options. To identify dysregulated genes and/or pathways that may play a role in tumorigenesis and/ or progression, molecular profiling was performed on 14 gonadotrope tumors and 9 normal human pituitaries from autopsy samples. Principle component analysis (PCA) revealed clear discrimination between tumor and normal pituitary gene expression profiles. Bioinformatic analysis identified specific genes and pathways that were highly differentially regulated, including a cohort of putative downstream effectors of p53 were repressed in gonadotrope pituitary tumors, including GADD45, GADD45 and Reprimo with concomitant downregulation of the upstream regulator, PLAGL1. PLAGL1 reexpression in gonadotrope cells did not directly modulate the downstream targets. Further functional analysis of GADD45 was performed. Overexpression of GADD45 in mouse gonadotrope cells blocked proliferation, increased rates of apoptosis in response to growth factor withdrawal and increased colony formation in soft agar. In contrast to prior studies with GADD45, methylation interference assays showed no evidence of epigenetic modification of the GADD45 promoter in pituitary tumors. Thus, our data suggest that many components downstream of p53 are suppressed in gonadotrope pituitary tumors. A novel candidate, GADD45 is low in tumors and reexpression blocks proliferation, survival and tumorigenesis in gonadotrope cells. Unlike GADD45, GADD45 is not methylated to block its expression. Together these studies identify new targets and mechanisms to explore concerning pituitary tumor initiation and progression.
Identification of growth arrest and DNA-damage-inducible gene beta (GADD45beta) as a novel tumor suppressor in pituitary gonadotrope tumors.
Sex
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Gene expression profiling-based identification of molecular subtypes in stage IV melanomas with different clinical outcome.
Sex, Specimen part
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