In 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 SamplesThe epicardium, an epithelium covering the heart, is essential for cardiac development. During embryogenesis, the epicardium provides instructive signals for the growth and maturation of cardiomyocytes and for coronary angiogenesis. We generated an in vitro model of human embryonic epicardium derived from human pluripotent stem cells (hPSC-epi). These cells were able to differentiate into cardiac fibroblasts (cf) and smooth muscle cells (smc) in vitro (hPSC-epi-cf and hPSC-epi-smc respectively). Furthermore, we showed that they improved maturation of hPSC-derived cardiomyocytes (hPSC-cardio) in vitro while neural crest cells derived from hPSC (hPSC-NC) could not. Furthermore, they improved survival of hPSC-cardio and stimulated angiogenesis when injected in a rat model of myocardium infarction. We performed mRNA sequencing of the hPSC-epi, hPSC-epi-cf, hPSC-smc and hPSC-NC in order to identify the secreted molecules specifically produced by the hPSC-epi and/or its derivatives in comparison with the hPSC-NC. Vascular smooth muscle cells have different embryonic origins and different properties depending on their location in the body. The coronary smooth muscle cells come from the epicardium while the aortic ones come from the mesoderm or the neural crest. We performed mRNA sequencing of human coronary artery smc and human aortic smc to identify a specific signature of the coronary smc. We also compared the genes expressed in the hPSC-epi-smc and the smc derived from hPSC-derived lateral plate mesoderm. Overall design: For hPSC-derived samples the three replicates are coming from three different in vitro differentiations from H9. For the human primary cells, the triplicates are technical replicates (three different wells from the same culture at the same passage)
Epicardial cells derived from human embryonic stem cells augment cardiomyocyte-driven heart regeneration.
Specimen part, Subject
View SamplesHere we analyse single cell transcriptome profiles of EZH2-deficient human embroynic stem cells Overall design: Single cell transcriptome (mRNA-Seq) from Ezh2-/- (Null) and EZH2+/+ (WT) human ESC
Deletion of the Polycomb-Group Protein EZH2 Leads to Compromised Self-Renewal and Differentiation Defects in Human Embryonic Stem Cells.
Specimen part, Subject
View SamplesThe homeobox containing gene Arx is expressed during ventral telencephalon development and it is required for correct GABAergic interneuron tangential migration from the ganglionic eminences to the olfactory bulbs, cerebral cortex and striatum. Its human ortholog is associated with a variety of neurological clinical manifestations whose syntoms are compatible with a loss of cortical interneurons and altered basal ganglia related-activities in humans. Herein, we reported the identification by global expression profiling of a group of genes whose expression is consistently altered in Arx mutant ganglionic eminences. Following analysis revealed the striking ectopic expression in the ganglionic eminences of a number of genes normally not, or only marginally, expressed in the ventral telencephalon. Among them, we functionally analyzed Ebf3, whose ectopic expression in ventral telencephalon is preventingneuronal tangential migration. Further, we showed that Arx is sufficient to repress Ebf3 endogenous expression and that its silencing in Arx mutant tissue might marginally rescue tangential cell movements. Together, these data provide an initial analysis of the molecular pathways regulated by Arx and how their networking might regulate those specific cellular processes during telencephalon development strongly altered by loss of Arx.
Arx acts as a regional key selector gene in the ventral telencephalon mainly through its transcriptional repression activity.
No sample metadata fields
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Distinct Gene Regulatory Pathways for Human Innate versus Adaptive Lymphoid Cells.
Specimen part
View SamplesInnate lymphoid cells (ILCs) serve as sentinels in mucosal tissues, sensing release of soluble inflammatory mediators, rapidly communicating danger via cytokine secretion, and functioning as guardians of tissue homeostasis. Although ILCs have been studied extensively in model organisms, little is known about these first responders in humans, especially their lineage and functional kinships to cytokine-secreting T helper cell (Th) counterparts. Here, we report gene regulatory circuitries for four human ILCTh counterparts derived from mucosal environments, revealing that each ILC subset diverges as a distinct lineage from Th and circulating natural killer cells, but shares circuitry devoted to functional polarization with their Th counterparts. Super-enhancers demarcate cohorts of cell identity genes in each lineage, uncovering new modes of regulation for signature cytokines, novel molecules that likely impart important functions to ILCs, and potential mechanisms for autoimmune disease SNP associations within ILCTh subsets.
Distinct Gene Regulatory Pathways for Human Innate versus Adaptive Lymphoid Cells.
Specimen part
View SamplesPressure overload-induced cardiac hypertrophy was examined in IL-18 knockout and littermate control mice.
Interleukin-18 knockout mice display maladaptive cardiac hypertrophy in response to pressure overload.
Specimen part
View SamplesThe 6-hydroxydopamine (6OHDA) rat model of parkinsonism is among the first, and most commonly used, animal models of Parkinsons disease. It provides insight into the compensatory changes that occur in the brain after dopamine (DA) neuron degeneration. In order to better define the consequences of substantia nigra DA neuron loss on the neural and glial populations during and following nigrostriatal degeneration, tissue was collected and evaluated from the substantia nigra of 6OHDA or vehicle treated, or nave rats at 1, 2, 4, 6 & 16 weeks.
The longitudinal transcriptomic response of the substantia nigra to intrastriatal 6-hydroxydopamine reveals significant upregulation of regeneration-associated genes.
Sex, Specimen part
View SamplesThe subsets of immune cells within the human placenta are incompletely described. We used microarray to determine the transcriptional differences between two myeloid subsets in the term human placenta.
Two Distinct Myeloid Subsets at the Term Human Fetal-Maternal Interface.
Specimen part
View SamplesRationale: Pulmonary arterial hypertension is a common and potentially fatal complication of scleroderma that may involve inflammatory and autoimmune mechanisms. Alterations in the gene expression of peripheral blood mononuclear cells have been previously described in patients with pulmonary arterial hypertension. The ability to identify patients at risk for developing pulmonary hypertension would be clinically beneficial.
Altered immune phenotype in peripheral blood cells of patients with scleroderma-associated pulmonary hypertension.
Sex, Specimen part, Disease, Disease stage
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