Objective: Resident macrophages play an important role in atheromatous plaque rupture. The macrophage gene expression signature associated with plaque rupture is incompletely defined due to the complex cellular heterogeneity in the plaque. We aimed to characterise differential gene expression in resident plaque macrophages from ruptured and stable human atheromatous lesions. A cell-specific approach has the potential to address the question of gene expression differences between particular cell types in stable and unstable plaques with greater precision than approaches based on the study of whole plaques. Using laser micro-dissection, we isolated total RNA from macrophage-rich regions of stable and ruptured human atheromatous plaques derived from carotid endarterectomy samples which were comprehensively characterized using clinical, radiological and histological criteria, and carried out genome-wide gene expression profiling using microarrays.
Increased expression of fatty acid binding protein 4 and leptin in resident macrophages characterises atherosclerotic plaque rupture.
Sex, Age, Specimen part
View SamplesIn platelets, splicing and translation occur in the absence of a nucleus. However, the integrity and stability of mRNAs derived from megakaryocyte progenitor cells remain poorly quantified on a transcriptome-wide level. As circular RNAs (circRNAs) are resistant to degradation by exonucleases, their abundance relative to linear RNAs can be used as a surrogate marker for mRNA stability in the absence of transcription. Here we show that circRNAs are enriched in human platelets 17-188 fold relative to nucleated tissues, and 14-26 fold relative to samples digested with RNAseR to selectively remove linear RNA. We compare RNAseq read depths inside and outside circRNAs to provide in silico evidence of transcript circularity, show that exons within circRNAs are enriched ~13X in platelets relative to nucleated tissues, and identify 3162 genes significantly enriched for circRNAs including some where all RNAs appear to be derived from circular molecules. We also confirm that this is a feature of other anucleate cells through transcriptome sequencing of mature erythrocytes, demonstrate that circRNAs are not enriched in megakaryocytes, and that linear RNAs decay more rapidly than circRNAs in platelet preparations. Collectively, these results suggest that circulating platelets have lost on aveage over 90% of their progenitor mRNAs, and that translation in platelets occurrs against the backdrop of a highly degraded transcriptome. Finally, we find that transcripts classified as products of reverse transcriptase template switching are both enriched in platelets and resistant to decay, countering the recent suggestion that up to 50% of rearranged RNAs are artefacts. Overall design: A single rRNA depleted total RNA sample was sequenced. This together with 25 publicly available rRNA depleted total RNA samples (including 3 from platelets) were analysed using PTESFinder v 1 (http://sourceforge.net/projects/ptesfinder-v1/) to identify back-splice junctions, characteristic of circRNA transcripts. The contribution of circRNA producing exons was analysed on a gene by gene basis as follows: All circRNA transcripts identified in any sample were first pooled to define exons which can contribute to circRNA generation using custom scripts (available on request). For each sample, expression estimates (RPKMI) across all circRNA producing exons were computed for each locus using the total size of exons (in bp) and the read counts mapping to them. Similarly, total size and exonic read counts for exons for which no circRNA were detected in any sample were used to compute expression estimates (RPKME) for non-circRNA producing exons for each locus. Abundance ratios (RPKMI/RPKME and RPKMI/RPKMI+RPKME) were calculated and compared between Platelets and human tissues using Wilcoxon signed-rank test. Please note that the ''25sample_info_accn_no.txt'' contains the accession numbers and tissue/cell type information for 25 samples analyzed together.
Circular RNA enrichment in platelets is a signature of transcriptome degradation.
No sample metadata fields
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Identification of candidate genes involved in neuroblastoma progression by combining genomic and expression microarrays with survival data.
Sex, Age
View SamplesGene expression analysis was performed on 30 Neuroblastomas to identify genes whose transcription is significantly altered by recurrent chromosomal alterations. Genomic copy number losses and gains had been delineated in the tumours using FISH and SNP arrays. We have identified genes significantly altered by 7 recurrent alterations: 1p, 3p, 4p, 10q and 11q loss, 2p and 17q gain, and genes co-amplified and over-expressed as a result of MYCN amplification.
Identification of candidate genes involved in neuroblastoma progression by combining genomic and expression microarrays with survival data.
Sex, Age
View SamplesHematopoiesis occurs in a microenviroenment in which stromal cells are prominent. Stromal cells have been shown to maintain stem cell behaviour of hematopoietic stem cells. We derived several different stromal cell lines from midgestation embryos which will, or will not maintain hemetopoietic stem cells in cultures.
Efficient hematopoietic differentiation of human embryonic stem cells on stromal cells derived from hematopoietic niches.
No sample metadata fields
View SamplesThe underlying mechanisms which are responsible and govern early haematopoietic differentiation during development are poorly understood. Gene expression comparison between pluripotent human embryonic stem cells and earliest haematopoietic progenitors may reveal novel transcripts and pathways and provide crucial insight into early haematopoietic lineage specification and development.
Large-scale transcriptional profiling and functional assays reveal important roles for Rho-GTPase signalling and SCL during haematopoietic differentiation of human embryonic stem cells.
Specimen part, Cell line
View SamplesMacrophage activation by bacterial lipopolysaccharides (LPS) is induced through Toll-like receptor 4 (TLR4). The synthesis and activity of TLR4 downstream signalling molecules modulates the expression of pro- and anti-inflammatory cytokines. To address the impact of post-transcriptional regulation on that process, we performed RIP-Chip analysis. Differential association of mRNAs with heterogeneous ribonucleoprotein K (hnRNP K), an mRNA-specific translational regulator in differentiating haematopoietic cells, was studied in non-induced and LPS-activated macrophages. Analysis of interactions affected by LPS revealed an enrichment of mRNAs encoding TLR4 downstream kinases and their modulators. We focused on transforming growth factor activated kinase-1 (TAK1), a central player in TLR4 signalling. HnRNP K interacts specifically with a sequence in the TAK1 mRNA 3' UTR in vitro. Silencing of hnRNP K does not affect TAK1 mRNA synthesis and stability, but enhances TAK1 mRNA translation, resulting in elevated TNF-alpha, IL-1beta and IL-10 mRNA expression. Our data suggest that the hnRNP K-3' UTR complex inhibits TAK1 mRNA translation in non-induced macrophages. LPS-dependent TLR4 activation abrogates translational repression and newly synthesised TAK1 initiates the inflammatory response of macrophages.
Translation control of TAK1 mRNA by hnRNP K modulates LPS-induced macrophage activation.
Specimen part, Cell line, Treatment
View SamplesHIV1+ smokers develop emphysema at an earlier age and with a higher incidence than HIV1- smokers. Based on the knowledge that human alveolar macrophages (AM) are capable of producing proteases that degrade extracellular matrix components, we hypothesized that upregulation of AM matrix metalloproteinases may be associated with the emphysema of HIV1+ smokers. To test this hypothesis, microarray analysis was used to screen which MMP genes were expressed by AM isolated by bronchoalveolar lavage (BAL) of HIV1+ smokers with early emphysema. For each of the MMP genes observed to be expressed (MMP-1, -2, -7, -9, -10, -12 and -14), TaqMan PCR was used to quantify the relative expression in AM from 4 groups of individuals: HIV1 healthy nonsmokers, HIV1- healthy smokers, HIV1- smokers with early emphysema and HIV1+ smokers with early emphysema. Strikingly, while AM gene expression of MMPs was higher in HIV1- individuals with emphysema in comparison with HIV1- healthy smokers, for the majority of the MMPs (-1, -7, -9, -10, -12), AM expression from HIV1+ smokers with early emphysema was significantly higher than HIV1- smokers with early emphysema. Consistent with these observations, HIV1+ individuals with early emphysema had higher levels of epithelial lining fluid MMPs (-2, -7, -9,-12) than the 3 HIV1 groups. Interestingly, the active forms of MMP-2, -9 and -12 were detected in epithelial lining fluid from HIV1+ individuals with early emphysema, but not in any of the other groups. Considering that the substrate specificity of the upregulated AM MMPs includes collagenases, gelatinases, matrilysins and elastase, these data suggest that upregulated AM MMP genes and activation of MMP proteins may contribute to the emphysema of HIV1+ individuals who smoke.
Up-regulation of alveolar macrophage matrix metalloproteinases in HIV1(+) smokers with early emphysema.
Sex, Age
View SamplesWe derived a transcriptional signature of oncogenic KRAS by using the KF508 murine pancreatic ductal cell line with an inducible Lox-Stop-Lox (LSL) cassette in front of the KRASG12D oncogene to regulate transcription. This dataset allowed us to study the differential expression profile after oncogenic KRAS induction in mouse.
Master Regulators of Oncogenic KRAS Response in Pancreatic Cancer: An Integrative Network Biology Analysis.
Cell line, Treatment
View SamplesStalk borers are major pests for some of the most important crops in the world, such as maize or rice. Plant defense mechanisms against these herbivores have been poorly investigated. The maizes stalk responds to insect feeding activating defense genes including hormone biosynthetic-related or proteinase inhibitor transcripts. The most outstanding conclusion is that cells in the maizes stalk undergo cell wall fortification after corn borer tunneling.
Inducible maize defense mechanisms against the corn borer Sesamia nonagrioides: a transcriptome and biochemical approach.
Specimen part
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