This SuperSeries is composed of the SubSeries listed below.
Parkinson's disease induced pluripotent stem cells with triplication of the α-synuclein locus.
Specimen part
View SamplesA major barrier to research on Parkinsons disease (PD) is inaccessibility of diseased tissue for study. One solution is to derive induced pluripotent stem cells (iPSCs) from patients with PD and differentiate them into neurons affected by disease. We created an iPSC model of PD caused by triplication of SNCA encoding -synuclein. -Synuclein dysfunction is common to all forms of PD, and SNCA triplication leads to fully penetrant familial PD with accelerated pathogenesis. After differentiation of iPSCs into neurons enriched for midbrain dopaminergic subtypes, those from the patient contain double -synuclein protein compared to those from an unaffected relative, precisely recapitulating the cause of PD in these individuals. A measurable biomarker makes this model ideal for drug screening for compounds that reduce levels of -synuclein, and for mechanistic experiments to study PD pathogenesis.
Parkinson's disease induced pluripotent stem cells with triplication of the α-synuclein locus.
Specimen part
View SamplesA major barrier to research on Parkinsons disease (PD) is inaccessibility of diseased tissue for study. One solution is to derive induced pluripotent stem cells (iPSCs) from patients with PD and differentiate them into neurons affected by disease. We created an iPSC model of PD caused by triplication of SNCA encoding -synuclein. -Synuclein dysfunction is common to all forms of PD, and SNCA triplication leads to fully penetrant familial PD with accelerated pathogenesis. After differentiation of iPSCs into neurons enriched for midbrain dopaminergic subtypes, those from the patient contain double -synuclein protein compared to those from an unaffected relative, precisely recapitulating the cause of PD in these individuals. A measurable biomarker makes this model ideal for drug screening for compounds that reduce levels of -synuclein, and for mechanistic experiments to study PD pathogenesis.
Parkinson's disease induced pluripotent stem cells with triplication of the α-synuclein locus.
Specimen part, Cell line
View SamplesThis study is to find the cellular and molecular mechanisms by which a naturally-occurring Np53 isoform causes accelerated aging in humans. The biological function of Np53, which lacks only 40 N-terminal amino acids, represents an example of p53 as a regulator of mammalian aging. When expressed together with WTp53 in mice, Np53 causes an aging phenotype such as shorter life span, reduced body mass, organ atrophy and osteoporosis. Because p53 must form a tetramer to regulate transcription, we generated p53 clones (based upon the structure of the native p53 tetramer) containing one Np53 linked with one WTp53 to form a functional Np53:WTp53 tetramer with 1:1 stoichiometry. Thus, our strategy ensured each p53 tetramer contained 2 Np53 and 2 WTp53 proteins. Importantly, Np53:WTp53 form stable tetramers, based upon gel filtration chromatography and structural analysis using electron microscopy. Furthermore, the Np53:WTp53 tetramer activates transcription equally well compared with WTp53 tetramers in an in vitro reconstituted transcription system. Having verified the stoichiometry, stability, structure, and activity of these Np53:WTp53 tetramers, here we used microarray analysis to compare global gene expression patterns in p53-null H1299 cells expressing either WTp53 or Np53:WTp53. As expected, global gene expression was largely similar, since the differences between Np53:WTp53 tetramers and WTp53 tetramers are slight: only 2 of 4 p53 proteins will be different in the Np53:WTp53 tetramer. Among only several dozen genes that were selectively up- or down-regulated 2-fold or greater, many genes known to regulate mammalian aging were altered in cells expressing Np53:WTp53, including insulin signaling pathway members (IRS1, INPP5D, PLK3, MAP3K1, FGF5) and regulators of glucose metabolism (SLC2A2, CRYAB, LRCH1). Expression of other key metabolic genes were also altered in cells expressing Np53:WTp53 tetramers, suggesting that global me tabolic changes might contribute to Np53:WTp53 pathology. In collaboration with Metabolon (Durham, NC), we identified approximately one hundred metabolites that were significantly up- or down-regulated in H1299 cells expressing Np53:WTp53. The metabolome analysis was a powerful complement to the gene expression data, and further suggested that the mTOR pathway (e.g. across-the-board up-regulation of amino acid levels) and mitochondrial function (e.g. up-regulation of carnitine, important for a-oxidation of fatty acids) was altered in cells expressing Np53:WTp53. These findings were subsequently validated using biochemical and cell-based approaches. Furthermore, whereas equal expression of Np53 and WTp53 cause accelerated aging in mammals, due to alternative splicing and translation initiation Np53 is a naturally-occurring isoform whose expression levels can change throughout the lifetime. Thus, the cellular and molecular mechanisms identified from this work will likely reflect changes common to normal, physiological aging.
The human ΔNp53 isoform triggers metabolic and gene expression changes that activate mTOR and alter mitochondrial function.
Specimen part, Cell line
View SamplesThe Mediator complex allows communication between transcription factors and RNA polymerase II (RNAPII). CDK8, the kinase found in some variants of Mediator, has been characterized mostly as a transcriptional repressor. Recently, CDK8 was demonstrated to be a potent oncoprotein. Here we show that CDK8 is predominantly a positive regulator of gene expression within the serum response network, as it is required for expression of several members of the AP-1 and EGR family of oncogenic transcription factors (e.g. FOS, JUN, EGR1-3). Mechanistic studies demonstrate that CDK8 is not required for recruitment of RNAPII and promoter escape at these loci. Instead, CDK8 depletion leads to the appearance of slower elongation complexes carrying hypophosphorylated RNAPII. We show that CDK8-Mediator regulates precise steps in the assembly of a functional elongation complex, including the recruitment of P-TEFb and BRD4, but is dispensable for recruitment of SPT5 and FACT. Furthermore, CDK8-Mediator specifically interacts with P-TEFb. Thus, we uncovered a novel role for CDK8 in transcriptional regulation that may contribute to its oncogenic effects.
CDK8 is a positive regulator of transcriptional elongation within the serum response network.
Cell line
View SamplesObjective: Conflicting evidence exists regarding the suppressive capacity of Tregs from the peripheral blood (PB) of patients with rheumatoid arthritis (RA). Our aim was to determine whether Tregs are intrinsically defective in RA using a wide range of read-out assays. Methods: CD3+CD4+CD25+CD127low Tregs from CD45RO+ and CD45RA+ compartments of PB from patients with RA and healthy controls (HC) were analysed for phenotype, cytokine expression profile (ex vivo and after in vitro stimulation), suppression of effector T-cell proliferation and cytokine production, suppression of monocyte-derived cytokine/chemokine production, and gene expression profiling. Results: No differences were observed between patients with RA and HC regarding Treg frequency, ex vivo phenotype (CD4, CD25, CD127, CD39, CD161) or pro-inflammatory cytokine profile (IL-17, IFN-gamma, TNF-alpha). FOXP3 expression was increased in Tregs from RA blood. The ability of Tregs to suppress T-cell proliferation or cytokine (IFN-gamma, TNF-alpha) production upon co-culture with autologous CD45RO+ effector T-cells and monocytes was not significantly different between patients with RA and HC. CD45RO+ Tregs from RA blood showed a slightly impaired ability to suppress production of some cytokines/chemokines by autologous LPS-activated monocytes (IL-1-beta, IL-1Ra, IL-7, CCL3, CCL4), but this was not true for all patients and other cytokines/chemokines (TNF-alpha, IL-6, IL-8, IL-12, IL-15, CCL5) were suppressed in the majority of patients similarly to HC. Finally, gene expression profiling of CD45RA+ or CD45RO+ Tregs from PB revealed no statistically significant differences between patients with RA and HC. Conclusions: Our findings suggest that Tregs isolated from PB of patients with RA are not intrinsically defective.
Phenotypic, Functional, and Gene Expression Profiling of Peripheral CD45RA+ and CD45RO+ CD4+CD25+CD127(low) Treg Cells in Patients With Chronic Rheumatoid Arthritis.
Specimen part, Disease, Disease stage, Subject
View SamplesCD14+ monocytes sorted from the synovial fluid or peripheral blood of rheumatoid arthritis patients were analyzed by full transcriptome microarray analysis. Monocytes from healthy control samples (peripheral blood) were also profiled.
MicroRNA-155 contributes to enhanced resistance to apoptosis in monocytes from patients with rheumatoid arthritis.
Specimen part, Disease, Disease stage, Subject
View SamplesCortistatin A (CA) is a highly selective inhibitor of the Mediator kinases CDK8 and CDK19. Using CA, we report here the first large-scale identification of Mediator kinase substrates in human cells (HCT116). Among over 16,000 quantified phosphosites, we identified 78 high-confidence Mediator kinase targets within 64 proteins, including DNA-binding transcription factors and proteins associated with chromatin, DNA repair, and RNA polymerase II. Although RNA-Seq data correlated with Mediator kinase targets, CA effects on gene expression were limited and distinct from CDK8 or CDK19 knockdown. Quantitative proteome analyses, which tracked about 7,000 proteins across six time points (0 – 24h), revealed that CA selectively affected pathways implicated in inflammation, growth, and metabolic regulation; contrary to expectations, increased turnover of Mediator kinase targets was not generally observed. Collectively, these data support Mediator kinases as regulators of chromatin and RNA polymerase II activity and suggest cellular roles beyond transcription, including metabolism and DNA repair. Overall design: HCT116 cells were treated with either 100nM CA or DMSO in biological triplicate for each population (6 samples total). Treatment was for 24h for compound and vehicle.
Identification of Mediator Kinase Substrates in Human Cells using Cortistatin A and Quantitative Phosphoproteomics.
No sample metadata fields
View SamplesHuman CD4+ T cells and CD14+ monocytes from healthy donors were co-cultured with anti-CD3 for three days in the presence or absence of TNF-alpha mAb (Adalimumab). Classical Th17 cells (Th17) or those generated in the presence of the inhibitor (iTh17) were then sorted and analyzed by full transcriptome microarray analysis.
TNF-α blockade induces IL-10 expression in human CD4+ T cells.
Specimen part, Treatment, Subject
View SamplesGene expression is controlled by transcription factors (TFs) that consist of DNA-binding domains (DBDs) and activation domains (ADs). The DBDs have been well- characterized, but little is known about the mechanisms by which ADs effect gene activation. Here we report that diverse ADs form phase-separated condensates with the Mediator coactivator. For the OCT4 and GCN4 TFs, we show that the ability to form phase-separated droplets with Mediator in vitro and the ability to activate genes in vivo are dependent on the same amino acid residues. For the estrogen receptor (ER), a ligand-dependent activator, we show that estrogen enhances phase separation with Mediator, again linking phase separation with gene activation. These results suggest that diverse TFs can interact with Mediator through the phase-separating capacity of their ADs and that formation of condensates with Mediator is involved in gene activation. Overall design: RNA-seq in mouse embryonic stem cells after OCT4 degradation or LIF withdrawal
Transcription Factors Activate Genes through the Phase-Separation Capacity of Their Activation Domains.
Treatment, Subject
View Samples