Spinocerebellar ataxia type 2 (SCA2) is a neurodegenerative disorder, which is caused by an unstable CAG-repeat expansion in the SCA2 gene, that encodes a polyglutamine tract (polyQ-tract) expansion in ataxin-2 protein (ATXN2). The RNA-binding protein ATXN2 interacts with the poly(A)-binding protein PABPC1, localizing to ribosomes at the rough endoplasmic reticulum or to polysomes. Under cell stress ATXN2 and PABPC1 show redistribution to stress granules where mRNAs are kept away from translation and from degradation. It is unknown whether ATXN2 associates preferentially with specific mRNAs or how it modulates their processing. Here, we investigated Atxn2 knock-out (Atxn2-/-) mouse liver, cerebellum and midbrain regarding their RNA profile, employing oligonucleotide microarrays for screening and RNA deep sequencing for validation. Modest ~1.4-fold upregulations were observed for the level of many mRNAs encoding ribosomal proteins and other translation pathway factors. Quantitative reverse transcriptase PCR and immunoblots in liver tissue confirmed these effects and demonstrated an inverse correlation also with PABPC1 mRNA and protein. ATXN2 deficiency also enhanced phosphorylation of the ribosomal protein S6, while impairing the global protein synthesis rate, suggesting a block between the enhanced translation drive and the impaired execution. Furthermore, ATXN2 overexpression and deficiency retarded cell cycle progression. ATXN2 mRNA levels showed a delayed phasic twofold increase under amino acid and serum starvation, similar to ATXN3, but different from motor neuron disease genes MAPT and SQSTM1. ATXN2 mRNA levels depended particularly on mTOR signalling. Altogether the data implicate ATXN2 in the adaptation of mRNA translation and cell growth to nutrient availability and stress.
Genetic ablation of ataxin-2 increases several global translation factors in their transcript abundance but decreases translation rate.
Age, Specimen part
View SamplesCombined treatment with NRG-1 and DMSO led to efficient differentiation of iPS into mature ventricular-like cardiac cells, which were capable of preserving cardiac function and tissue viability when transplanted into a mouse model of myocardial infarction.
Neuregulin-1β induces mature ventricular cardiac differentiation from induced pluripotent stem cells contributing to cardiac tissue repair.
Sex
View SamplesTo identify a cohort of rhythmically expressed genes in the murine Distal Colon,microarrays were used to measure gene expression over a 24-hour light/dark cycle.The rhythmic transcripts were classified according to expression patterns, functions and association with physiological and pathophysiological processes of the colon including motility, colorectal cancer formation and inflammatory bowel disease.
Transcriptional profiling of mRNA expression in the mouse distal colon.
No sample metadata fields
View SamplesThe primary goal of toxicology and safety testing is to identify agents that have the potential to cause adverse effects in humans. Unfortunately, many of these tests have not changed significantly in the past 30 years and most are inefficient, costly, and rely heavily on the use of animals. The rodent cancer bioassay is one of these safety tests and was originally established as a screen to identify potential carcinogens that would be further analyzed in human epidemiological studies. Today, the rodent cancer bioassay has evolved into the primary means to determine the carcinogenic potential of a chemical and generate quantitative information on dose-response behavior in chemical risk assessments. Due to the resource-intensive nature of these studies, each bioassay costs $2 to $4 million and takes over three years to complete. Over the past 30 years, only 1,468 chemicals have been tested in a rodent cancer bioassay. By comparison, approximately 9,000 chemicals are used by industry in quantities greater than 10,000 lbs and nearly 90,000 chemicals have been inventoried by the U.S. Environmental Protection Agency as part of the Toxic Substances Control Act. Given the disparity between the number of chemicals tested in a rodent cancer bioassay and the number of chemicals used by industry, a more efficient and economical system of identifying chemical carcinogens needs to be developed.
Application of genomic biomarkers to predict increased lung tumor incidence in 2-year rodent cancer bioassays.
Sex, Age, Subject
View SamplesWhile the reprogramming factors OCT4, SOX2, KLF4, and MYC (OSKM) can reactivate the pluripotency network in terminally differentiated cells, they also regulate expression of non-pluripotency genes in other contexts, such as the mouse primitive endoderm. The primitive endoderm is an extraembryonic lineage established alongside the pluripotent epiblast in the blastocyst, and is the progenitor pool for extraembryonic endoderm stem (XEN) cells. Several studies have shown that endodermal genes are upregulated in fibroblasts undergoing reprogramming, although whether endodermal genes promote or inhibit acquisition of pluripotency is unclear. We show that, in fibroblasts undergoing conventional reprogramming, OSKM-induced expression of endodermal genes leads to formation of induced XEN (iXEN) cells, which possess key properties of blastocyst-derived XEN cells, including morphology, transcription profile, self-renewal, and multipotency. Our data show that iXEN cells arise in parallel to iPS cells, indicating that OSKM are sufficient to drive cells to two distinct fates during reprogramming. Overall design: Sequence-based mRNA transcriptional profiling of three different cell lines (MEF, XEN, iXEN) with multiple biological replicates, under two different growth medium conditions (ESC medium, XEN medium) for XEN and iXEN cells.
OSKM Induce Extraembryonic Endoderm Stem Cells in Parallel to Induced Pluripotent Stem Cells.
Specimen part, Treatment, Subject
View SamplesThe capacity of cancer cells to undergo epithelial mesenchymal trans-differentiation has been implicated as a factor driving metastasis, through the acquisition of enhanced migratory/invasive cell programs and the engagement of anti-apoptotic mechanisms promoting drug and radiation resistance. Our aim was to define molecular signaling changes associated with mesenchymal trans-differentiation in two KRas mutant NSCLC models. We focused on central transcription and epigenetic regulators predicted to be important for mesenchymal cell survival. Overall design: Haley, J.A., Haughney, E., Ullman, E., Bean, J., Haley, J.D.* and Fink, M.Y. (2014) 'Altered Transcriptional Control Networks with Trans-Differentiation of Isogenic Mutant KRas NSCLC Models' Front. Oncology, doi/10.3389/fonc.2014.00344.
Altered Transcriptional Control Networks with Trans-Differentiation of Isogenic Mutant-KRas NSCLC Models.
Treatment, Subject
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Esrrb extinction triggers dismantling of naïve pluripotency and marks commitment to differentiation.
Specimen part, Cell line
View SamplesSelf-renewal of embryonic stem cells (ESCs) cultured in serum-LIF is incomplete with some cells initiating differentiation. While this is reflected in heterogeneous expression of naive pluripotency transcription factors (TFs), the link between TF heterogeneity and differentiation is not fully understood. Here we purify ESCs with distinct TF expression levels from serum-LIF cultures to uncover early events during commitment from nave pluripotency. ESCs carrying fluorescent Nanog and Esrrb reporters show Esrrb downregulation only in NANOGlow cells. Independent Esrrb reporter lines demonstrate that ESRRBnegative ESCs cannot effectively self-renew. Upon ESRRB loss, pre-implantation pluripotency gene expression collapses. ChIP-Seq identifies different regulatory element classes that bind both OCT4 and NANOG in ESRRBhigh cells. Class I elements lose NANOG and OCT4 binding in ESRRBnegative ESCs and associate with genes expressed preferentially in nave ESCs. In contrast, class II elements retain OCT4 but not NANOG binding in ESRRBnegative cells and associate with more broadly expressed genes. Therefore, mechanistic differences in TF function act cumulatively to restrict potency during exit from nave pluripotency.
Esrrb extinction triggers dismantling of naïve pluripotency and marks commitment to differentiation.
Specimen part
View SamplesPolycomb repressive complex-2 (PRC2) is a group of proteins that play important role during development and in cell differentiation. PRC2 is a histone-modifying complex that catalyses methylation of lysine 27 of histone H3 (H3K27me3) at differentiation genes leading to their transcriptional repression. JARID2 is a co-factor of PRC2 and is important for targeting PRC2 to chromatin as well as modulating its activity. Here, we show that in many human cells, including human epidermal keratinocytes, JARID2 predominantly exists as a novel low molecular weight form, which lacks the N-terminal PRC2-interacting domain (?N-JARID2). We show that ?N-JARID2 is a cleaved product of full-length JARID2 spanning the C-terminal conserved region consisting of jumonji domains. JARID2 knockout in keratinocytes results in up-regulation of cell cycle genes and repression of many epidermal differentiation genes. Surprisingly, repression of epidermal differentiation genes in JARID2-null keratinocytes can be relieved by expression of ?N-JARID2 suggesting that this form promotes activation of these genes and has opposing function to that of PRC2 in regulation of differentiation. We propose that a switch from expression of full-length JARID2 to ?N-JARID2 is important for the up-regulation of genes during differentiation. Overall design: RNA-seq analysis of Wildtype and JARID2-null keratinocytes (HaCaTs) on day 0 and day 3 of calcium induced differentiation.
A novel form of JARID2 is required for differentiation in lineage-committed cells.
Specimen part, Cell line, Subject
View SamplesThe transcriptomes of FACS-sorted siglec-F+ alveolar macrophages and siglec-f- CD11b+ exudative macrophages from inducible airway GM-CSF over-expressing transgenic mice (DTGM) were compared to non-inducible littermate controls during influenza A virus infection. Overall design: Examination of effect of GM-CSF on airway macrophages during influenza A virus infection
GM-CSF overexpression after influenza a virus infection prevents mortality and moderates M1-like airway monocyte/macrophage polarization.
Sex, Specimen part, Cell line, Subject
View Samples