Most human pre-mRNAs are spliced into linear molecules that retain the exon order defined by the genomic sequence. By deep sequencing of RNA from a variety of normal and malignant human cells, we found RNA transcripts from many human genes in which the exons were arranged in a non-canonical order. Statistical estimates and biochemical assays provided strong evidence that a substantial fraction of the spliced transcripts from hundreds of genes are circular RNAs. Our results suggest that a non-canonical mode of RNA splicing, resulting in a circular RNA isoform, is a widespread and perhaps general feature of the gene expression program in human cells. Overall design: 3 samples of non-malignant primary human leukocytes, one replicate each
Circular RNAs are the predominant transcript isoform from hundreds of human genes in diverse cell types.
Specimen part, Subject
View SamplesThe complex milieu of inflammatory mediators associated with many diseases is often too dilute to directly measure in the periphery, necessitating development of more sensitive measurements suitable for mechanistic studies, earlier diagnosis, guiding selection of therapy, and monitoring interventions. Previously, we determined that plasma of recent-onset (RO) Type 1 diabetes (T1D) patients induce a proinflammatory transcriptional signature in fresh peripheral blood mononuclear cells (PBMC) relative to that of unrelated healthy controls (HC). Here, using an optimized cryopreserved PBMC-based protocol, we apply this approach to inflammatory bowel disease by examining groups of Crohn's disease (CD) and ulcerative colitus (UC) patients. The induced plasma induced signatures are compared to those of Type 1 diabetes patients (RO T1D) as well as unrelated healthy controls (uHC).
Plasma-induced signatures reveal an extracellular milieu possessing an immunoregulatory bias in treatment-naive paediatric inflammatory bowel disease.
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View SamplesGene fusions are known to play critical roles in tumor pathogenesis. However, sensitive and specific algorithms to detect gene fusions in cancer do not currently exist. Although real RNA-seq data from cell lines or tumors can be used in testing new fusion detection algorithms, it is impossible to know the true sensitivity or specificity of an algorithm without knowing the "ground truth". For this reason we designed a synthetic control data set to assess the true and false positive and negative fusions of a a new fusion detection algorithm.
Statistical algorithms improve accuracy of gene fusion detection.
Sex, Specimen part
View SamplesWe discovered induction of circular RNA in human fetal tissues, including the heart. In this study, we were able to recapitulate this induction by in vitro directed differentiation of hESCs to cardiomyocytes, paving the way for future studies into circular RNA regulation. Overall design: We harvested hESCs at sequential stages of differentiation: undifferentiated (day 0), mesoderm (day 2), cardiac progenitor (day 5) and definitive cardiomyocyte (day 14). We performed RNA sequencing in biological triplicate, with 3-8 technical replicates each.
Statistically based splicing detection reveals neural enrichment and tissue-specific induction of circular RNA during human fetal development.
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View SamplesThe pervasive expression of circular RNA from protein coding loci is a recently discovered feature of many eukaryotic gene expression programs. Computational methods to discover and quantify circular RNA are essential to the study of the mechanisms of circular RNA biogenesis and potential functional roles they may play. In this paper, we present a new statistical algorithm that increases the sensitivity and specificity of circular RNA detection.by discovering and quantifying circular and linear RNA splicing events at both annotated exon boundaries and in un-annotated regions of the genome Unlike previous approaches which rely on heuristics like read count and homology between exons predicted to be circularized to determine confidence in prediction of circular RNA expression, our algorithm is a statistical approach. We have used this algorithm to discover general induction of circular RNAs in many tissues during human fetal development. We find that some regions of the brain show marked enrichment for genes where circular RNA is the dominant isoform. Beyond this global trend, specific circular RNAs are tissue specifically induced during fetal development, including a circular isoform of NCX1 in the developing fetal heart that, by 20 weeks, is more highly expressed than the linear isoform as well as beta-actin. In addition, while the vast majority of circular RNA production occurs at canonical U2 (major spliceosome) splice sites, we find the first examples of developmentally induced circular RNAs processed by the U12 (minor) spliceosome, and an enriched propensity of U12 donors to splice into circular RNA at un-annotated, rather than annotated, exons. Together, our algorithm and its results suggest a potentially significant role for circular RNA in human development. Overall design: 35 human fetal samples from 6 tissues (3 - 7 replicates per tissue) collected between 10 and 20 weeks gestational time were sequenced using Illumina TruSeq Stranded Total RNA with Ribo-Zero Gold sample prep kit.
Statistically based splicing detection reveals neural enrichment and tissue-specific induction of circular RNA during human fetal development.
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View SamplesUnderstanding the molecular underpinnings of cancer is of critical importance to developing targeted intervention strategies. Identification of such targets, however, is notoriously difficult and unpredictable. Malignant cell transformation requires the cooperation of a few oncogenic mutations that cause substantial reorganization of many cell features and induce complex changes in gene expression patterns. Genes critical to this multi-faceted cellular phenotype thus only have been identified following signaling pathway analysis or on an ad hoc basis. Our observations that cell transformation by cooperating oncogenic lesions depends on synergistic modulation of downstream signaling circuitry suggest that malignant transformation is a highly cooperative process, involving synergy at multiple levels of regulation, including gene expression. Here we show that a large proportion of genes controlled synergistically by loss-of-function p53 and Ras activation are critical to the malignant state. Remarkably, 14 among 24 such 'cooperation response genes' (CRGs) were found to contribute to tumor formation in gene perturbation experiments. In contrast, only one in 14 perturbations of genes responding in a non-synergistic manner had a similar effect. Synergistic control of gene expression by oncogenic mutations thus emerges as an underlying key to malignancy and provides an attractive rationale for identifying intervention targets in gene networks downstream of oncogenic gain and loss-of-function mutations.
Synergistic response to oncogenic mutations defines gene class critical to cancer phenotype.
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View SamplesThe relative contribution of polarized macrophages to the maintenance of tolerance is unknown. We examined their roles by in vivo adoptive transfer immunotherapy of M0, M1 and M2a macrophages as pre-treatment of colitis. In other experiments, M2a macrophages were used as pre-treatment or treatment of established colitis followed by immunotherapy with nTreg cells. Survival, weight gain, tissue infiltration, iTreg and Th17 cell development, T cell activation, and the frequency of proinflammatory cytokines were used as outcome measurements. Pre-treatment with M2a but not M1 macrophages increased the development of iTreg and Th17 cells. M2a macrophages used as pre-treatment or in treatment of established colitis allowed for successful therapy with nTreg cells.
Alternatively Activated Macrophages Boost Induced Regulatory T and Th17 Cell Responses during Immunotherapy for Colitis.
Age, Specimen part
View SamplesThe incidence of Type 1 diabetes (T1D), a T-cell mediated autoimmunity that targets the insulin secreting -cells, has significantly increased, suggesting greater environmental pressure. In studies of T1D families and the BioBreeding rat model, we have identified a peripheral innate inflammatory state that is associated with diabetes susceptibility, consistent with pattern recognition receptor (PRR) ligation, but independent of disease progression. Here, compared to control strains, islets of spontaneously diabetic BB DRlyp/lyp and nondiatetic BB DR+/+ weanlings provided a standard cereal diet were found to temporally express a proinflammatory transcriptional program consistent with microbial antigen exposure that included numerous cytokines/chemokines. Dependence of this proinflammatory phenotype on the diet and gastrointestinal microbiota was investigated by transitioning DR+/+ weanlings to a hydrolyzed casein diet (HCD) or treating them with antibiotics to respectively alter or reduce PRR ligand exposure.
Modulation of the diet and gastrointestinal microbiota normalizes systemic inflammation and β-cell chemokine expression associated with autoimmune diabetes susceptibility.
Age, Specimen part
View SamplesInduced Treg (iTreg) cells are essential for tolerance and can be used therapeutically, yet their stability in vivo and mechanisms of suppression are unresolved. Here, we used a treatment model of colitis to examine the role of autologous IL-10 in iTreg cell function. Mice treated with IL-10+/+ iTreg cells in combination with IL-10/ natural Treg (nTreg) cells survived and gained weight, even though iTreg cells were numerically disadvantaged and comprised just ~20% of all Treg cells in treated mice. Notably, ~85% of the transferred iTreg cells lost Foxp3 expression (ex-iTreg) but retained a portion of the iTreg transcriptome which failed to limit their pathogenic potential. The TCR repertoires of iTreg and ex-iTreg cells exhibited almost no overlap, which indicates that the two populations are clonally unrelated and maintained by different selective pressures. These data demonstrate a potent and critical role for iTreg cell produced IL-10 that can supplant the IL-10 produced by nTreg cells and compensate for the inherent instability of the iTreg population.
IL-10 produced by induced regulatory T cells (iTregs) controls colitis and pathogenic ex-iTregs during immunotherapy.
Treatment
View SamplesConsumption of a protein containing meal by a fasted animal promotes protein accretion in skeletal muscle, in part through leucine stimulation of protein synthesis and indirectly through repression of protein degradation mediated by its metabolite, a-ketoisocaproate. Mice lacking the mitochondrial branched-chain aminotransferase (BCATm/Bcat2), that interconverts leucine and a-ketoisocaproate, exhibit elevated protein turnover. Here, the transcriptomes of gastrocnemius muscle from BCATm knockout (KO) and wildtype mice were compared using Next Generation RNA-Sequencing (RNA-Seq) to identify potential adaptations associated with their persistently altered nutrient signaling. Statistically significant changes in the abundance of 1486/~39,010 genes were identified. Bioinformatics analysis of the RNA-Seq data indicated that pathways involved in protein synthesis (eIF2, mTOR, eIF4 and p70S6K pathways including 40S and 60S ribosomal proteins), protein breakdown (e.g., ubiquitin mediated), and muscle degeneration (apoptosis, atrophy, myopathy and cell death) were up-regulated. Also in agreement with our previous observations, the abundance of mRNAs associated with reduced body size, glycemia, plasma insulin, and lipid signaling pathways were observed in BCATm KO mice. Consistently, genes encoding anaerobic and/or oxidative metabolism of carbohydrate, fatty acids and BCAAs were modestly but systematically reduced. Although there was no indication that muscle fiber type was different between KO and wildtype mice, a difference in the abundance of mRNAs associated with a muscular dystrophy phenotype was observed, consistent with the published exercise intolerance of these mice. The results suggest transcriptional adaptations occur in BCATm KO mice that along with altered nutrient signaling may contribute to their previously reported protein turnover, metabolic and exercise phenotypes. Overall design: Comparison of wildtype and BCATm KO gastrocnemius biological replicates
Global deletion of BCATm increases expression of skeletal muscle genes associated with protein turnover.
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