Heterogeneous pools of adult neural stem cells (NSCs) contribute to brain maintenance and regeneration after injury. The balance of NSC activation and quiescence, as well as the induction of lineage-specific transcription factors, may contribute to diversity of neuronal and glial fates. To identify molecular hallmarks governing these characteristics, we performed single-cell sequencing of an unbiased pool of adult subventricular zone NSCs. This analysis identified a discrete, dormant NSC subpopulation that already expresses distinct combinations of lineage-specific transcription factors during homeostasis. Dormant NSCs enter a primed-quiescent state before activation, which is accompanied by downregulation of glycolytic metabolism, Notch, and BMP signaling and a concomitant upregulation of lineage-specific transcription factors and protein synthesis. In response to brain ischemia, interferon gamma signaling induces dormant NSC subpopulations to enter the primed-quiescent state. This study unveils general principles underlying NSC activation and lineage priming and opens potential avenues for regenerative medicine in the brain. Overall design: Single cell RNAseq of cells isolated from their in vivo niche in the subventricular zone, Striatum and Cortex during homeostasis as well as following ischemic injury. In total 272 single cells. (<WT>: homeostasis samples; <Ischemic_injured> and <Ischemic_injured_and_Interferon_gamma_knockout>: samples following ischemic injuried).
Single-Cell Transcriptomics Reveals a Population of Dormant Neural Stem Cells that Become Activated upon Brain Injury.
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View SamplesMany studies have addressed the effects of adult diet on gene expression in Drosophila melanogaster, however, little is known about how developmental diet influences adult gene expression, and how this interacts with adult dietary conditions.
Relating past and present diet to phenotypic and transcriptomic variation in the fruit fly.
Sex, Specimen part
View SamplesEnsuring cooperation among formerly autonomous cells has been a central challenge in the evolution of multicellular organisms. One solution is monoclonality, but this option does not eliminate genetic and epigenetic variability, leaving room for exploitative behavior. We therefore hypothesized that embryonic development must be protected by robust regulatory mechanisms that prevent aberrant clones from superseding wild-type cells. Using a genome-wide screen in murine induced pluripotent stem cells, we identified a network of genes (centered on p53, topoisomerase 1, and olfactory receptors) whose downregulation caused the cells to replace wild-type cells, both in vitro and in the mouse embryowithout perturbing normal development. These genes thus appear to fulfill an unexpected role in fostering cell cooperation.
Safeguards for cell cooperation in mouse embryogenesis shown by genome-wide cheater screen.
Specimen part, Treatment
View SamplesThe mechanisms underlying natural variation in lifespan and ageing rate remain largely unknown.
Transcriptome analysis of a long-lived natural Drosophila variant: a prominent role of stress- and reproduction-genes in lifespan extension.
Sex, Specimen part
View SamplesThe present study aims to explore the role of Rim15 in both physiology and genome wide expression in S. cerevisiae under severe caloric restriction. Non-growing but metabolically active cultures of S. cerevisiae are of major interest for application in industry and as model systems for aging in higher eukaryotes. Using retentostat cultivations, almost non-growing but metabolic active cultures can be obtained resulting from the severe caloric restriction, yet not starvation, yeast experiences. Rim15 plays an important role in several nutrient sensing pathways and is involved in activating stress response and glycogen accumulation upon nutrient shortage. To investigate the role of Rim15 in the extreme robustness and glycogen accumulation of anaerobic retentostat cultures, a rim15 deletion strain is compared with its parental strain under anaerobic calorie restriction on both physiology and transcriptome.
To divide or not to divide: a key role of Rim15 in calorie-restricted yeast cultures.
No sample metadata fields
View SamplesHeterozygous mutations in the transcription factor GATA3 are identified in 10-15% of all breast cancer cases. Most of these are protein-truncating mutations, concentrated within or downstream of the second GATA-type zinc-finger domain. Here, we investigated the functional consequences of expression of two truncated GATA3 mutants, in vitro in breast cancer cell lines and in vivo in the mouse mammary gland. We found that the truncated GATA3 mutants display altered DNA binding activity caused by preferred tethering through FOXA1. In addition, expression of the truncated GATA3 mutants reduces E-cadherin expression and promotes anchorage-independent growth in vitro. However, we could not identify any effects of truncated GATA3 expression on mammary gland development or mammary tumor formation in mice. Together, our results demonstrate that both truncated GATA3 mutants promote cistromic re-programming of GATA3 in vitro, but these mutants are not sufficient to induce tumor formation in mice. Overall design: RNAseq data of T47D cells expressing HA-tagged wild-type GATA3 (HA_GATA3_wt) or one of two truncated variants (HA_GATA3_TR1 and HA_GATA3_TR2).
GATA3 Truncating Mutations Promote Cistromic Re-Programming In Vitro, but Not Mammary Tumor Formation in Mice.
Specimen part, Cell line, Subject
View SamplesBackground and aims: Dysregulation of intestinal epithelial cells performance associates with an array of pathologies whose onset mechanisms are incompletely understood. The aim of the present study was to provide a map of gene expresssion patterns along the human healthy adult gastro-intestinal tract and to implement a new procedure for microarray data noise filtering that would allow their use as a reference when screening for pathological deviations, such as inflammatory bowel disease (IBD). Methods: Gene expression profiles in antrum, duodenum, jejunum, ileum and transverse colon biopsies were measured with the Affymetrix U133A array and principal component analysis was used to identify region-selective biomarkers. These data were intersected with highly variable genes from a public dataset of gene expression in the ileal and colonic healthy regions of UC and Crohns disease patients. Moreover, gene sets covering gut functions not entirely accounted for by the available public tools were constructed to monitor their expression along the GI tract. Results: 166 genes were found to be responsible for distinguishing the five regions considered. Fourteen had never been described in the GI tract, including a semaphorin probably implicated in pathogen invasion, and six other novel genes. Similar analysis of the IBD datasets revealed that samples stratify based on disease rather than on the intestinal region. This withstanding, eleven genes were identified as possible early predictors of Crohns and/or UC in ileum and/or colon. These include CLCA4 and SLC26A2, both implicated in ion transport. Conclusions: This novel approach, validated by retrieving known gene profiles, allowed the identification of promising new leads both in health and IBD state.
Biomarkers of human gastrointestinal tract regions.
Age
View SamplesNeuroblastoma cell lines can differentiate upon retinoic acid (RA) treatment, a finding that provided the basis for the clinical use of RA to treat neuroblastoma. However, resistance to RA is often observed, which limits its clinical utility. Using a gain-of-function genetic screen we identify the transcriptional coactivator Mastermind-like 3 (MAML3) as a gene whose ectopic expression confers resistance to RA. We find that MAML3 expression leads to loss of activation of a subset of RA target genes, which hampers RA-induced differentiation. The regulatory DNA elements of this subset of RA target genes show overlap in binding of MAML3 and the retinoic acid receptor, suggesting a role for MAML3 in the regulation of these genes. In addition, MAML3 has RA independent functions, including the activation of IGF1R and downstream AKT signaling via upregulation of IGF2, resulting in increased proliferation. Our results indicate an important role for MAML3 in differentiation and proliferation of neuroblastomas. Overall design: RNA-seq of SK-N-SH control and MAML3 overexpressing (SD3.23) cells, either untreated (UT) or treated with 1 µM RA (RA).
Mastermind-Like 3 Controls Proliferation and Differentiation in Neuroblastoma.
No sample metadata fields
View SamplesHuman X-box binding protein-1 (XBP1) is an alternatively spliced transcription factor that participates in the unfolded protein response (UPR), a stress signaling pathway that allows cells to survive the accumulation of unfolded proteins in the endoplasmic reticulum lumen. We have previously demonstrated that XBP1 expression is increased in antiestrogen-resistant breast cancer cell lines, and is co-expressed with estrogen receptor alpha (ER) in breast tumors. The purpose of this study is to investigate the role of XBP1 and the UPR in estrogen and antiestrogen responsiveness in breast cancer. Overexpression of spliced XBP1 (XBP1(S)) in ER-positive breast cancer cells leads to estrogen-independent growth and reduced sensitivity to growth inhibition induced by the antiestrogens Tamoxifen and Faslodex in a manner independent of functional p53. Data from gene expression microarray analyses imply that XBP1(S) acts through regulating the expression of ER, the anti-apoptotic gene BCL2, and several other genes associated with control of the cell cycle and apoptosis.
Human X-box binding protein-1 confers both estrogen independence and antiestrogen resistance in breast cancer cell lines.
No sample metadata fields
View SamplesDystonia is characterized by involuntary muscle contractions. Its many forms are genetically, phenotypically and etiologically diverse and it is unknown whether their pathogenesis converges on shared pathways. Mutations in THAP1, a zinc-finger transcription factor, cause DYT6, but its neuronal targets and functions are unknown. We used RNA-Seq to assay the in vivo effect of a heterozygote Thap1C54Y or ?Exon2 allele on the gene transcription signatures in neonatal mouse striatum and cerebellum. Enriched pathways and gene ontology terms include eIF2a Signaling, Mitochondrial Dysfunction, Neuron Projection Development, Axonal Guidance Signaling, and Synaptic Long Term Depression pathways, which are dysregulated in a genotype and tissue-dependent manner. Electrophysiological and neurite outgrowth assays confirmed the functional significance of those findings. Notably, several of these pathways were recently implicated in other forms of inherited dystonia, including DYT1. We conclude that dysfunction of these pathways may represent a point of convergence on the pathogenesis of unrelated forms of inherited dystonia. Overall design: We used RNA-Seq to assay the in vivo effect of a heterozygote Thap1C54Y or deltaExon2 allele on the gene transcription signatures in neonatal mouse striatum and cerebellum
Mutations in THAP1/DYT6 reveal that diverse dystonia genes disrupt similar neuronal pathways and functions.
Specimen part, Cell line, Subject
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