A-to-I RNA editing is a conserved and widespread phenomenon in which adenosine (A) is converted to inosine (I) by adenosine deaminases (ADARs) in double-stranded RNA regions. Although human RNAs contain millions of A-to-I editing sites, most of these occur in noncoding regions and their function is unknown. Knockdown of ADAR enzymes in C. elegans causes defects in normal development but is not lethal as it is in human and mouse, making C. elegans an ideal organism for studying the regulatory effects of RNA editing on the transcriptome. Previous studies in C. elegans indicated competition between RNA interference (RNAi) and RNA editing mechanisms, with the observation that lack of both mechanisms can suppress defects observed when only RNA editing is absent. To study the effects of RNA editing on gene expression and function, we established a novel screen that enabled to identify thousands of RNA editing sites in non-repetitive regions in the genome. These include dozens genes that are edited at their 3’UTR region. We found that these genes are mainly germline and neuronal genes and that they are downregulated in the absence of ADAR enzymes. Moreover, we discovered that almost half of these genes are edited in a developmental-specific manner. In addition, we found that many pseudogenes and other lncRNAs are also extensively downregulated in the absence of ADARs in embryo but not L4 larva developmental stage, while this downregulation is not observed in additional knockout of RNAi. Taken together, our results suggest a role for RNA editing in normal growth and development by regulating silencing via RNAi. Overall design: RNA-seq samples were generated from: 1. wildtype (N2) at embryo stage 2. wildtype (N2) at L4 stage 3. ADAR mutant (BB21 or BB4) worms at L4 stage 4. ADAR mutant (BB21 or BB4) worms at embryo stage 5. ADAR mutant and RNAi mutant (BB23, BB24) at embryo stage RNA in high and low molecular weight fractions was extracted by mirVana kit (ambion). mRNA was sequenced from the high molecular weight fraction by means of Illumina TruSeq® RNA Sample Preparation kit automated by Agilent Bravo Automated Liquid Handling Platform. The resulting libraries were sequences with an Illumina HiSeq 2500.
A-to-I RNA editing promotes developmental stage-specific gene and lncRNA expression.
Specimen part, Cell line, Subject
View SamplesWe examined gene expression of LAPC4 cells after knocking down -TrCP, androgen ablation, or the combined treatments compared to non treated cells.
beta-TrCP inhibition reduces prostate cancer cell growth via upregulation of the aryl hydrocarbon receptor.
Cell line
View SamplesThe tumorigenicity of human pluripotent stem cells (hPSCs) is a major safety concern for their application in regenerative medicine. Here we identify the tight-junction protein Claudin-6 as a specific cell surface marker of hPSCs that can be used to selectively remove Claudin-6-positive cells from mixed cultures. We show that Claudin-6 is absent in adult tissues but highly expressed in undifferentiated cells, where it is dispensable for hPSC survival and self-renewal. We use three different strategies to remove Claudin-6-positive cells from mixed populations: an antibody against Claudin-6; a cytotoxin-conjugated antibody that selectively targets undifferentiated cells; and clostridium perfringens enterotoxin, a toxin that binds several Claudins, including Claudin-6, and efficiently kills undifferentiated cells, thus eliminating the tumorigenic potential of hPSC-containing cultures. This work provides a proof of concept for the use of Claudin-6 to eliminate residual undifferentiated hPSCs from culture, highlighting a strategy that may increase the safety of hPSC-based cell therapies.
Immunologic and chemical targeting of the tight-junction protein Claudin-6 eliminates tumorigenic human pluripotent stem cells.
Specimen part, Cell line
View SamplesPluripotent-specific inhibitors (PluriSIns) make a powerful tool for studying the mechanisms that control the survival of human pluripotent stem cells (hPSCs). Here we characterize PluriSIn#2 as a novel selective indirect inhibitor of topoisomerase II alpha (TOP2A). We find that TOP2A is uniquely expressed in undifferentiated hPSCs, and that its inhibition results in their rapid cell death. These findings reveal a dependency of hPSCs on the activity of TOP2A, which can be harnessed for their selective elimination from culture.
Brief reports: Controlling the survival of human pluripotent stem cells by small molecule-based targeting of topoisomerase II alpha.
Specimen part, Cell line, Treatment
View SamplesWe aimed to determine whether overexpression of endoderm-specific miRNA may affect hESC differentiation. To this end, we analyzed the effect of lentiviral-based overexpression of liver-specific miR-122 on hESC differentiation, using genomewide gene microarrays. Stable overexpression of endoderm-specific miR-122 in hESC resulted in increased expression of a few endodermal markers in spontaneously-differentiating hESC, but had no clear effect on directing differentiation towards an endodermal fate; rather, it delayed the general differentiation of hESC.
MicroRNA expression patterns and function in endodermal differentiation of human embryonic stem cells.
Cell line
View SamplesPD is the second most common neurodegenerative disease worldwide with growing prevalence. MPTP is a neurotoxin which causes the appearance of Parkinson's disease (PD) pathology. The involvement of the cholinergic system in PD has been identified decades ago and anti-cholinergic drugs were upon the first drugs used for symptomatic treatment of PD. Of note, MPTP intoxication is a model of choice for symptomatic neuroprotective therapies since it have been quite predictive. Mice were exposed to the dopaminergic neurotoxin 1-methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine (MPTP), with or without the protective acetylcholinesterase (AChE-R) variant. Transgenic AChE-S (the synaptic variant), AChE-R (the shorter, protective variant) and FVB/N control mice were included in this study. Two brain regions were examined: the pre-frontal cortex (PFC) and the striatal caudate-putamen (CPu). Each condition (i.e brain region and transgenic variant) was examined on both naive and MPTP-exposed mice.
Meta-analysis of genetic and environmental Parkinson's disease models reveals a common role of mitochondrial protection pathways.
Specimen part, Treatment
View SamplesWe isolated and selected intestinal adenoma organoids from villin-CreER; Apcflox/flox and villin-CreER; Apcflox/flox; Prox1flox/flox mice and added tamoxifen to induce the deletion of the Apc and Prox1 genes in the intestinal epitheliul ex vivo. Microarray experiments were carried out 7 days after the addition of tamoxifen.
Prox1 promotes expansion of the colorectal cancer stem cell population to fuel tumor growth and ischemia resistance.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Oncogenic mutations in intestinal adenomas regulate Bim-mediated apoptosis induced by TGF-β.
Specimen part, Treatment
View SamplesIntestinal crypts isolated from Apcflox/flox; villin-CreERT mice were treated with Tamoxifen to induce the deletion of Apc. Tamoxifen-treated organoids were selected in the absence of Wnt agonists and then treated with TGF-beta.
Oncogenic mutations in intestinal adenomas regulate Bim-mediated apoptosis induced by TGF-β.
Specimen part, Treatment
View SamplesHuman pluripotent stem cells (hPSCs) tend to acquire chromosomal aberrations in culture, which may increase their tumorigenicity. However, the cellular mechanism(s) underlying these aberrations are largely unknown. Here we show that the DNA replication in aneuploid hPSCs is perturbed, resulting in high prevalence of defects in chromosome condensation and segregation. Global gene expression analyses in aneuploid hPSCs revealed decreased levels of actin cytoskeleton genes and their common transcription factor SRF. Down-regulation of SRF or chemical perturbation of actin cytoskeleton organization in diploid hPSCs resulted in increased replication stress and perturbation of chromosome condensation, recapitulating the findings in aneuploid hPSCs. Altogether, our results revealed that in hPSCs DNA replication stress results in a distinctive defect in chromosome condensation, underlying their ongoing chromosomal instability. Our results shed a new light on the mechanisms leading to ongoing chromosomal instability in hPSCs, and may be relevant to tumor development as well.
Genomic Instability in Human Pluripotent Stem Cells Arises from Replicative Stress and Chromosome Condensation Defects.
Specimen part, Cell line
View Samples