Covalently closed circular RNA molecules (circRNAs) have recently emerged as a class of RNA isoforms with widespread and tissue specific expression across animals, oftentimes independent of the corresponding linear mRNAs. circRNAs are remarkably stable and sometimes highly expressed molecules. Here, we sequenced RNA in human peripheral whole blood to determine the potential of circRNAs as biomarkers in an easily accessible body fluid. We report the reproducible detection of thousands of circRNAs. Importantly, we observed that hundreds of circRNAs are much higher expressed than corresponding linear mRNAs. Thus, circRNA expression in human blood reveals and quantifies the activity of hundreds of coding genes not accessible by classical mRNA specific assays. Our findings suggest that circRNAs could be used as biomarker molecules in standard clinical blood samples. Overall design: Sequencing of blood RNA from five healthy individuals (biological replicates) plus technical replicate of one sample and detection of circRNAs.
Identification and Characterization of Circular RNAs As a New Class of Putative Biomarkers in Human Blood.
No sample metadata fields
View SamplesCellular circular RNAs (circRNAs) are generated by head-to-tail splicing and are present in all multicellular organisms studied so far. Recently, circRNAs have emerged as large class of RNA which can function as post-transcriptional regulators. It has also been shown that many circRNAs are tissue- and stage specifically expressed. Moreover, the unusual stability and expression specificity make circRNAs important candidates for clinical biomarker research. Here, we present a circRNA expression resource of twenty human tissues highly relevant to disease-related research: vascular smooth muscle cells (VSMCs), human umbilical vein (HUVECs), artery endothelial cells (HUAECs), atrium, vena cava, neutrophils, platelets, cerebral cortex, placenta, and samples from mesenchymal stem cell differentiation. In eight different samples from a single donor, we found highly tissue-specific circRNA expression. Circular-to-linear RNA ratios revealed that many circRNAs were higher expressed than their linear host transcripts. Among the 65 validated circRNAs, we noticed potential biomarkers. In adenosine deaminase-deficient, severe combined immunodeficiency (ADA-SCID) patients and in Wiskott-Aldrich-Syndrome (WAS) patients' samples, we found evidence for differential circRNA expression of genes that are involved in the molecular pathogenesis of both phenotypes. Our findings underscore the need to assess circRNAs in mechanisms of human disease. Overall design: To explore circRNA expression patterns in human tissues, we performed rRNA-depleted RNA sequencing and circRNA detection in twenty clinically relevant samples.
A map of human circular RNAs in clinically relevant tissues.
Specimen part, Disease, Subject
View SamplesCircular RNAs (circRNAs) are a large class of animal RNAs. To investigate possible circRNA functions, it is important to understand circRNA biogenesis. Besides human Alu repeats, sequence features that promote exon circularization are largely unknown. We experimentally identified new circRNAs in C. elegans. Reverse complementary sequences between introns bracketing circRNAs were significantly enriched compared to linear controls. By scoring the presence of reverse complementary sequences in human introns we predicted and experimentally validated novel circRNAs. We show that introns bracketing circRNAs are highly enriched in RNA editing or hyper-editing events. Knockdown of the double-strand RNA editing ADAR1 enzyme significantly and specifically up-regulated circRNA expression. Together, our data support a model of animal circRNA biogenesis in which competing RNA:RNA interactions of introns form larger structures which promote circularization of embedded exons, while ADAR1 antagonizes circRNA expression by melting stems within these interactions. Thus, we assign a new function to ADAR1. Overall design: Examination of 12 samples in different stages of C.elegans development.
Analysis of intron sequences reveals hallmarks of circular RNA biogenesis in animals.
Cell line, Treatment, Subject
View SamplesCircular RNAs (circRNAs) in animals are an enigmatic class of RNAs with unknown function. To systematically explore circRNAs, we sequenced and computationally analyzed human, mouse and nematode RNA. We detected thousands of well-expressed, stable circRNAs, with oftentimes tissue/developmental stage specific expression. Sequence analysis suggested important regulatory functions for circRNAs. Indeed, we discovered that human circRNA CDR1as is densely bound by miRNA effector complexes and harbors 63 conserved binding sites for the ancient miRNA miR-7. Further analyses indicated that CDR1as functions to bind miR-7 in neuronal tissues. Human CDR1as expression in zebra fish impaired midbrain development similar to knocking down miR-7, suggesting that CDR1as is a miRNA antagonist with a miRNA binding capacity ten times higher than any other known transcript. Together, our data provide evidence that circRNAs form a large class of post-transcriptional regulators. Numerous circRNAs form by head-to-tail splicing of exons, indicating previously unrecognized regulatory potential of coding sequences. Overall design: 1 Sample
Circular RNAs are a large class of animal RNAs with regulatory potency.
Cell line, Subject
View SamplesIn this study we predict functionally important long intergenic non-coding RNAs (lincRNAs) with a role in core essential processes in human. One of the candidate lincRNA, AC093323.3, was experimentally verified to affect cell viability. We performed RNASeq on knockdown of AC093323.3 to further investigate the functional role of this lincRNA. Overall design: RNA profiles of NCI-H460 lung cancer cells after treatment with scrambled siRNAs and AC093323.3-siRNA.
In silico prediction of housekeeping long intergenic non-coding RNAs reveals HKlincR1 as an essential player in lung cancer cell survival.
Cell line, Subject
View SamplesTumor hypoxia is associated with poor patient outcome and resistance to therapy. It is associated with a rapid decline in protein production mediated through mTOR signalling. Here we show that it also leads to widespread changes in splicing and a global shift towards the expression of noncoding isoforms, thus providing a novel and orthogonal mechanism by which cells can modulate protein expression. Overall design: Examination of mRNA levels in HCT116 cells after 0 hr, 1 hr, 2 hr and 24 hr in hypoxia. Three biological replicates each.
Hypoxia-driven splicing into noncoding isoforms regulates the DNA damage response.
Specimen part, Cell line, Treatment, Subject, Time
View SamplesHigh grade serous ovarian cancers (HGSC) are deadly malignancies that relapse despite carboplatin chemotherapy. Here we show that 16 independent primary HGSCs contain a CA125 negative population enriched for carboplatin resistant cancer initiating cells. Transcriptome analysis reveals up-regulation of homologous recombination DNA repair and anti-apoptotic signals in this population. While treatment with carboplatin enriches for CA125 negative cells, co-treatment with carboplatin and birinapant eliminates these cells in HGSCs expressing high levels of the inhibitor of apoptosis protein cIAP in the CA125 negative population. Birinapant sensitizes CA125 negative cells to carboplatin by mediating degradation of cIAP causing cleavage of caspase-8 and restoration of apoptosis. This co-therapy significantly improved disease free survival in vivo compared to either therapy alone in tumor-bearing mice. These findings suggest that therapeutic strategies that target CA125 negative cells may be useful in the treatment of HGSC. Overall design: mRNA profiles of CA125 positive and negative populations, generated by next generation sequencing of populations FACS isolated from 10 independent dissociated primary human high grade serous ovarian cancers, were compared.
An apoptosis-enhancing drug overcomes platinum resistance in a tumour-initiating subpopulation of ovarian cancer.
No sample metadata fields
View SamplesHigh grade serous ovarian cancers (HGSC) are deadly malignancies that relapse despite carboplatin chemotherapy. Many commercially ovarian cancer cell lines are not good models for HGSC. Here we demonstrate that 3 low passage cell lines derived from HGSC have similar transcriptomes to their parental bulk tumors. These cell lines recapitulated tumor characteristics of the primary cancer and had responded to therapy in the same manner as primary HGSC cells, demonstrating they are accurate models for HGSCs. Overall design: mRNA profiles of low passage high grade serous tumor cell lines and their parental tumors, generated by next generation sequencing, were compared.
An apoptosis-enhancing drug overcomes platinum resistance in a tumour-initiating subpopulation of ovarian cancer.
No sample metadata fields
View SamplesUnderstanding the mechanisms of host macrophage responses to Mycobacterium tuberculosis (M.tb.) is essential for uncovering potential avenues of intervention to boost host resistance to infection. Macrophage transcriptome profiling revealed M.tb. infection strongly induced expression of several enzymes controlling tryptophan (Trp) catabolism. This included indole 2,3-dioxygenase 1 (IDO1) and tryptophan 2,3-dioxygenase (TDO2), which catalyze the rate-limiting step in the kynurenine pathway, producing ligands for the aryl hydrocarbon receptor (AHR). The AHR and heterodimeric partners AHR nuclear translocator (ARNT) and RELB are robustly expressed, and AHR and RELB levels further increased during infection. Infection enhanced AHR/ARNT and AHR/RELB DNA binding, and stimulated expression of AHR target genes, including that encoding the inflammatory cytokine IL1beta. AHR target gene expression was further enhanced by exogenous kynurenine, and exogenous Trp, kynurenine or synthetic agonist indirubin reduced mycobacterial viability. Comparative expression profiling revealed that AHR ablation diminished expression of numerous genes implicated in innate immune responses, including several cytokines. Notably, AHR depletion reduced expression of IL23A and IL12B transcripts, which encode subunits of interleukin 23 (IL23), a macrophage cytokine that stimulates production of IL22 by innate lymphoid cells. The AHR directly induced IL23A transcription in human and mouse macrophages through near-upstream enhancer regions. Taken together, these findings show that AHR signaling is strongly engaged in Mtb-infected macrophages, and has widespread effects on innate immune responses. Moreover, they reveal a cascade of AHR-driven innate immune signaling, as IL1B (IL-1) and IL23 stimulate T cell subsets producing IL22, another direct target of AHR transactivation.
Engagement of the Aryl Hydrocarbon Receptor in Mycobacterium tuberculosis-Infected Macrophages Has Pleiotropic Effects on Innate Immune Signaling.
Cell line
View SamplesWe reported altered RNA expression profiles in wild-type (WT) C57BL/6J mice upon parenteral nutrition treatment compared to saline infusion controls.
Dysregulation of bile acid homeostasis in parenteral nutrition mouse model.
Specimen part
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