INTRODUCTION. Fixation with formalin, a widely adopted procedure to preserve tissue samples, leads to extensive degradation of nucleic acids and thereby compromises procedures like microarray-based gene expression profiling. We hypothesized that RNA fragmentation is caused by activation of RNAses during the interval between formalin penetration and tissue fixation. To prevent RNAse activation, a series of tissue samples were kept under-vacuum at 4C until fixation and then fixed at 4C, for 24 hours, in formalin followed by 4 hours in ethanol 95%.
Formalin fixation at low temperature better preserves nucleic acid integrity.
Specimen part
View SamplesWe used microarrays to provide a transcriptomic signature of different types of cholestasis evoked by 3 different drugs and obstructive surgery
Robustness testing and optimization of an adverse outcome pathway on cholestatic liver injury.
Specimen part, Cell line, Treatment
View SamplesColon gene expression in human IBD. The three major clinical subsets of Inflammatory Bowel Disease (IBD) include colon-only Crohn's Disease (CD), ileo-colonic CD, and Ulcerative Colitis (UC). These experiments tested differential colon gene expression in these three types of IBD, relative to healthy control samples, and the local degree of mucosal inflammation as measured by the CD Histological Index of Severity (CDHIS). Colon biopsy samples were obtained from IBD patients at diagnosis and during therapy, and healthy controls. The global pattern of gene expression was determined using GeneSpring software, with a focus upon candidate genes identified in a recent genome wide association study in pediatric onset IBD. Data suggested that two of these candidate genes are up regulated in pediatric IBD, partially influenced by local mucosal inflammation.
Loci on 20q13 and 21q22 are associated with pediatric-onset inflammatory bowel disease.
No sample metadata fields
View SamplesWhole transcriptome analysis of circulating B cells from multiple sclerosis (MS) patients and healthy donors (HD).
Analysis of coding and non-coding transcriptome of peripheral B cells reveals an altered interferon response factor (IRF)-1 pathway in multiple sclerosis patients.
Specimen part, Disease
View SamplesNOD2 is an intracellular receptor for the bacterial cell wall component muramyl dipeptide (MDP) and variants of NOD2 are associated with chronic inflammatory diseases of barrier organs e.g. Crohn disease, asthma and atopic eczema. It is known that activation of NOD2 induces a variety of inflammatory and antibacterial factors. The exact transcriptomal signatures that define the cellular programs downstream of NOD2 activation and the influence of the Crohn-associated variant L1007fsinsC are yet to be defined. To describe the MDP-induced activation program, we analyzed the transcriptomal reactions of isogenic HEK293 cells expressing NOD2wt or NOD2L1007fsinsC to stimulation with MDP. Importantly, a clear loss-of-function could be observed in the cells carrying the Crohn-associated variant L1007fsinsC, while the NOD2wt cells showed differential regulation of growth factors, chemokines and several antagonists of NF-B, e.g. TNFAIP3 (A20) and IER3.
Genome-wide expression profiling identifies an impairment of negative feedback signals in the Crohn's disease-associated NOD2 variant L1007fsinsC.
Cell line, Time
View SamplesThe multiple claims about reactivation of the embryonic stem cell (ESC) pluripotency factor OCT4 in somatic cells are highly controversial due to the fact that there is no direct evidence that OCT4 has a functional role in cells other than ESCs. Herein we demonstrate that smooth muscle cell (SMC)-specific knockout of Oct4 within atherosclerotic mice resulted in increased lesion size and multiple changes consistent with decreased plaque stability. SMC-lineage tracing studies showed that lesions from SMC-specific conditional Oct4 KO mice had a reduced number of SMCs likely due to impaired SMC migration. RNA-seq analysis of lesion specimens showed that loss of Oct4 in SMCs was associated with marked activation of genes associated with inflammation and suppression of genes associated with cell migration, a number of which were shown to be activated in cultured SMCs by the combination of hypoxia and oxidized phospholipids in an OCT4-dependent manner. Activation of Oct4 within SMCs was associated with hydroxymethylation of the Oct4 promoter and was HIF1a- and KLF4-dependent. Results provide the first genetic evidence that OCT4 plays a functional role in somatic cells and highlight the importance of further investigation of possible OCT4 functions in somatic cells. Overall design: In vivo: mRNA profiles of 18 week fed Western diet wild type (WT) and Oct4-/- mice were generated by deep sequencing, four animals per group, using Illumina HiSeq 2000. In vitro: a smooth muscle cell wild type (WT) and Oct4-/- (KO) primary aortic cell line was generated and used. mRNA profiles were generated by deep sequencing, in triplicates, using Illumina HiSeq 2000, for the following groups: WT-normoxia-vehicle; WT-normoxia-POVPC; KO-normoxia-vehicle; KO-normoxia-POVP; WT-hypoxia-vehicle; WT-hypoxia-POVPC; KO-hypoxia-vehicle; and KO-hypoxia-POVPC.
Perivascular cell-specific knockout of the stem cell pluripotency gene Oct4 inhibits angiogenesis.
Specimen part, Cell line, Treatment, Subject
View SamplesThe Microarray study was designed to characterize the whole genome transcription profile of two subpopulations of H1 human embryonic stem cells we identified by size using flow cytometry.The heterogeneous nature of stem cells is an important issue in both research and therapeutic use in terms of directing cell lineage differentiation pathways, as well as self-renewal properties. Using flow cytometry we have identified two distinct subpopulations by size within the H1 and BGN1 human embryonic stem (hES) cell lines. Both populations express stem the cell markers Oct-4, Nanog, Tra-1-60, Tra-1-80 and SSea-4 and express very low levels of differentiation markers common to the three germ layers. To investigate if the two populations possessed different transcription profiles, we performed whole genome microarray analysis, and identified approximately 400 genes with significant differential expression (p<0.01). Cloning experiments indicate that both populations are able to repopulate each other and maintain the parental population. The large cell population responds to retinoic acid (RA) differentiation as evidenced by greater than a 50% loss of gated cell number and loss of Oct-4 expression; while the small cell population number does not change and maintains Oct-4 protein expression. The presence of these two populations could be vitally important with respect to stem cell therapy and research as they respond differently to differentiation signals, which may be important in directing stem cell differentiation for disease therapy.
Differential responses to retinoic acid and endocrine disruptor compounds of subpopulations within human embryonic stem cell lines.
Specimen part, Disease, Cell line
View SamplesThese data provide scientific information to understand the mechanism of action of lapatinib resistance in HER2-positive patients and to test the combination of HER2-targeted agents and GSK1363089 (foretinib) in the clinic by using an acquired lapatinib-resistant cell line.
Novel mechanism of lapatinib resistance in HER2-positive breast tumor cells: activation of AXL.
Specimen part, Cell line, Treatment
View SamplesThis SuperSeries is composed of the SubSeries listed below.
The transcriptional network for mesenchymal transformation of brain tumours.
Time
View SamplesUsing a novel combination of cellular-network reverse-engineering algorithms and experimental validation assays, we identified a transcriptional module, including six transcription factors that synergistically regulates the mesenchymal signature of malignant glioma. This is a poorly understood molecular phenotype, never observed in normal neural tissue. It represents the hallmark of tumor aggressiveness in high-grade glioma, and its upstream regulation is so far unknown. Overall, the newly discovered transcriptional module regulates >74% of the signature genes, while two of its transcription factors (C/EBP and Stat3) display features of initiators and master regulators of mesenchymal transformation. Ectopic co-expression of C/EBP and Stat3 is sufficient to reprogram neural stem cells along the aberrant mesenchymal lineage, while simultaneously suppressing differentiation along the default neural lineages (neuronal and glial). Conversely, silencing the two transcription factors in human glioma cell lines and glioblastoma-derived tumor initiating cells leads to collapse of the mesenchymal signature with corresponding loss of tumor aggressiveness in vitro and in immunodeficient mice after intracranial injection. In human tumor samples, combined expression of C/EBP and Stat3 correlates with mesenchymal differentiation of primary glioma and is a predictor of poor clinical outcome. Taken together, these results reveal that activation of a small regulatory module inferred from the accurate reconstruction of transcriptional networks is necessary and sufficient to initiate and maintain an aberrant phenotypic state in eukaryotic cells.
The transcriptional network for mesenchymal transformation of brain tumours.
Time
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