The reprogramming of somatic cells into induced pluripotent stem cells (iPSCs) upon overexpression of OCT4, KLF4, SOX2 and c-MYC (OKSM) provides a powerful system to interrogate basic mechanisms of cell fate change. However, iPSC formation with standard methods is typically protracted and inefficient, resulting in heterogeneous cell populations. We show that exposure of OKSM-expressing cells to both ascorbic acid and a GSK3- inhibitor (AGi) facilitates more synchronous and rapid iPSC formation from several mouse cell types. AGi treatment restored the ability of refractory cell populations to yield iPSC colonies, and it attenuated the activation of developmental regulators commonly observed during the reprogramming process. Moreover, AGi supplementation gave rise to chimera-competent iPSCs after as little as 48 h of OKSM expression. Our results offer a simple modification to the reprogramming protocol, facilitating iPSC induction at unparalleled efficiencies and enabling dissection of the underlying mechanisms in more homogeneous cell populations.
Small molecules facilitate rapid and synchronous iPSC generation.
Specimen part, Treatment, Time
View SamplesWe studied the synaptic activity-regulated gene expression response in the human genetic background using cultured human iPSC-derived (hiPSCd) neuronal networks and networks of hiPSCd neurons mixed with mouse primary neurons. Our results confirm that genetic changes affect the synaptic activity-regulated gene program, proposing a functional mechanism how they have driven evolution of human cognitive abilities. Overall design: We compared RNA profiles of untreated hiPSCd neurons and hiPSCd neurons treated with bicuculline and 4-aminopyridine for 1 or 4 hours. Samples were collected from hiPSCd neuron-only cultures and from co-cultures of hiPSCd neurons and mouse primary hippocampal neurons.
Networks of Cultured iPSC-Derived Neurons Reveal the Human Synaptic Activity-Regulated Adaptive Gene Program.
Specimen part, Subject
View SamplesAnalysis of early and late changes in the mouse peritoneal cells in response to E. coli induced sepis. Result provide an insight into the molecular function and pathways expressed at these different time points.
Transcriptomic analysis of peritoneal cells in a mouse model of sepsis: confirmatory and novel results in early and late sepsis.
Sex, Treatment
View SamplesThe first described feedback loop of the Arabidopsis circadian clock is based on reciprocal regulation between TOC1 and CCA1/LHY. CCA1 and LHY are MYB transcription factors that bind directly to the TOC1 promoter to negatively regulate its expression. Conversely, the activity of TOC1 has remained less well characterized. Genetic data supports that TOC1 is necessary for the reactivation of CCA1/LHY, but there is little description of its biochemical function. Here we show that TOC1 occupies specific genomic regions in the CCA1 and LHY promoters. Purified TOC1 binds directly to DNA through its CCT domain, which is similar to known DNA binding domains. Chemical induction and transient overexpression of TOC1 in Arabidopsis seedlings cause repression of CCA1/LHY expression demonstrating that TOC1 can repress direct targets, and mutation or deletion of the CCT domain prevents this repression showing that DNA binding is necessary for TOC1 action. Furthermore, we use the Gal4/UAS system in Arabidopsis to show that TOC1 acts as a general transcriptional repressor, and that repression activity is in the Pseudoreceiver (PR) domain of the protein. To identify the genes regulated by TOC1 on a genomic scale, we couple TOC1 chemical induction with microarray analysis and identify new potential TOC1 targets and output pathways. Together these results define the biochemical action of the core clock protein TOC1 and refine our perspective on how plant clocks function.
Arabidopsis circadian clock protein, TOC1, is a DNA-binding transcription factor.
No sample metadata fields
View SamplesAnalysis of Drosophila melanogaster early embryos (pre-zygotic genome activation) following the germ line-specific depletion of the dMLL3/4 histone methyltransferase (also known as Trr). These results provide insight into the molecular mechanisms responsible for the assembly of the zygotic genome at fertilization.
The Trithorax group protein dMLL3/4 instructs the assembly of the zygotic genome at fertilization.
Specimen part
View SamplesThe goal of this gene expression profiling experiment was to identify the entire set of transcription factors expressed during late pupal wing development (~80h APF) when pigmentation genes are expressed
Emergence and diversification of fly pigmentation through evolution of a gene regulatory module.
Specimen part
View SamplesThe transcriptional response to many widely used drugs and its modulation by genetic variability is poorly understood. Here we present an analysis of RNAseq profiles from heart tissue of 18 inbred mouse strains treated with the ß-blocker atenolol (ATE) and the ß-agonist isoproterenol (ISO). Differential expression analyses revealed a large set of genes responding to ISO (n=1770 at FDR=0.0001) and a comparatively small one responding to ATE (n=23 at FDR=0.0001). At a less stringent definition of differential expression, the transcriptional responses to these two antagonistic drugs are reciprocal for many genes, with an overall anti-correlation of r= -0.3. This trend is also observed at the level of most individual strains even though the power to detect differential expression is significantly reduced. The inversely expressed gene sets are enriched with genes annotated for heart-related functions. Modular analysis revealed gene sets that exhibited coherent transcription profiles across some strains and/or treatments. Correlations between such modules and a broad spectrum of cardiovascular traits are stronger than expected by chance. This provides evidence for the overall importance of transcriptional regulation for these organismal responses and explicits links between co-expressed genes and the traits they are associated with. Gene set enrichment analysis of differentially expressed groups of genes pointed to pathways related to heart development and functionality. Our study provides new insights into the transcriptional response of the heart to perturbations of the ß-adrenergic system, implicating several new genes that had not been associated to this system previously. Overall design: Cardiac mRNA expression profiles of the various inbred mouse strains were examined either under baseline condition (control) or in response to chronic administration of isoproterenol or atenolol at 10 mg/kg per day for 2 weeks. Expression data were produced by RNA-sequencing, in triplicates, using the HiSeq 2000 Illumina platform. Only males, aged ten to twelve weeks on average, were included in the experimental protocol. Mouse ID numbers refer to those described in Berthonneche C. et al. PLoS One. 2009 Aug 12;4(8):e6610 (doi: 10.1371/journal.pone.0006610. PMID: 19672458). Corresponding individual phenotypic values, in particular heart rate, systolic blood pressure, electrocardiogaphic measurements and heart weight are available in dataset "maurer1" of the Mouse Phenome Database (http://phenome.jax.org/). Preparation of the sequencing libraries, RNA-sequencing and RNA expression quantitations were performed by the BGI.
RNAseq analysis of heart tissue from mice treated with atenolol and isoproterenol reveals a reciprocal transcriptional response.
Sex, Specimen part, Treatment, Subject
View Samplesp21-activated kinases (Paks) play an important role in oncogenic signaling pathways, and have therefore been considered as potential therapeutic targets in various cancers. Most studies of Pak function employ loss of function methods such as gene knock-out or knock-down, but these approaches result in loss of both the enzymatic and scaffolding properties of these proteins, and thus may not reflect the effects of small molecule inhibitors that block catalytic function. In this study we use a new transgenic mouse model in which a specific peptide inhibitor of Group I Paks (Pak1, -2, and -3) is conditionally expressed in response to Cre recombinase. Using this model, we show that inhibition of endogenous Pak function impedes the transition of adenoma to carcinoma in an Apc-driven mouse model of colorectal cancer. These effects are mediated by inhibition of Wnt signaling through reduced ß-catenin activity as well as suppression of an epithelial-mesenchymal transition program mediated by miR-200 and Snai1. These results highlight the potential therapeutic role of Pak1 inhibitors in colorectal cancer and suggest new therapeutic strategies in this disease. Overall design: We generated a targeted transgenic mouse carrying a conditionally activated PID allele at the Rosa26 locus, and showed that expression of this allele effectively inhibited the activity of Group I Paks in vivo. To assess the global molecular effects of Pak inhibition in Apc-null CRC cells, we next explored the effect of repressing Pak activity on transcription. Total RNA was extracted from PID+ and PID- cells and RNA-sequencing was preformed, followed by pathway analysis and qPCR validation for selected mRNAs.
Group I Paks are essential for epithelial- mesenchymal transition in an Apc-driven model of colorectal cancer.
Treatment, Subject
View SamplesShear stress is known to regulate endothelial cell orientation along the direction of flow. We asked wither cellular patterning along, in the absence of shear could have similar biological effects as shear.
Spatial patterning of endothelium modulates cell morphology, adhesiveness and transcriptional signature.
Specimen part, Treatment
View SamplesPurpose: The diagnosis of high grade intraductal papillary mucinous neoplasm (IPMN) is difficult to distinguish from low grade IPMN. The aim of this study was to identify potential markers for the discrimination of high grade and invasive IPMN from low and moderate grade IPMN.
Gene expression changes associated with the progression of intraductal papillary mucinous neoplasms.
Disease, Disease stage, Subject
View Samples