Changes ins organellar gene expression trigger retrograde signalling. Prolyl-tRNA synthetase (PRORS1) is located in chloroplasts and mitochondria. Thus, prors1-2 mutants are impaired in chloroplast and mitochondrial gene expression.
Identification of target genes and transcription factors implicated in translation-dependent retrograde signaling in Arabidopsis.
Age, Specimen part
View SamplesThe discovery of mammalian cardiac progenitor cells has suggested that the heart consists of not only terminally differentiated beating cardiomyocytes, but also a population of self-renewing stem cells with the potential to generate new cardiomyocytes (Anderson, Self et al. 2007; Bearzi, Rota et al. 2007; Wu, Chien et al. 2008). A consequence of longevity is continual exposure to environmental and xenobiotic stresses, and recent literature suggests that hematopoietic stem cell pools tightly control cell health through upregulation of the integrated stress response and consequent cellular mechanisms such as apoptosis. However, whether or not this biological response is conserved in progenitor cells for later lineages of tissue specific stem cells is not well understood. Using human induced pluripotent stem cells (iPSC) of both cardiac progenitor and mature cardiomyocyte lineages, we found that the integrated stress response was upregulated in the iPSC cardiac progenitors leading to an increased sensitivity for apoptosis relative to the mature cardiomyocytes. Of interest, C/EBP homologous protein (CHOP) signaling plays a mechanistic role in the cell death phenotype observed in iPSC progenitors, by which depletion of CHOP prevents cell death following cellular stress by thapsigargin exposure. Our studies suggest that the integrated stress response plays a unique role in maintaining iPSC cardiac progenitor cellular integrity by removing unhealthy cells via apoptosis following environmental and xenobiotic stresses, thus preventing differentiation and self-renewal of damaged cells.
The Integrated Stress Response Regulates Cell Health of Cardiac Progenitors.
Specimen part, Treatment
View SamplesRegeneration of lung epithelium is vital for maintaining airway function and integrity. An imbalance between epithelial damage and repair is at the basis of numerous chronic lung diseases such as asthma, COPD, pulmonary fibrosis and lung cancer. IGF (Insulin-like Growth Factors) signaling has been associated with most of these respiratory pathologies, although their mechanisms of action in this tissue remain poorly understood. Expression profiles analyses of IGF system genes performed in mouse lung support their functional implication in pulmonary ontogeny. Immuno-localization revealed high expression levels of Igf1r (Insulin-like Growth Factor 1 Receptor) in lung epithelial cells, alveolar macrophages and smooth muscle. To further understand the role of Igf1r in pulmonary homeostasis, two distinct lung epithelial-specific Igf1r mutant mice were generated and studied. The lack of Igf1r disturbed airway epithelial differentiation in adult mice revealed enhanced proliferation and altered morphology in distal airway club cells. During recovery after naphthalene-induced club cell injury, the kinetics of terminal bronchiolar epithelium regeneration was hindered in Igf1r mutants, revealing increased proliferation and delayed differentiation of club and ciliated cells. Amid airway restoration, lungs of Igf1r deficient mice showed increased levels of Igf1, Insr, Igfbp3 and epithelial precursor markers, reduced amounts of Scgb1a1 protein, and alterations in IGF signaling mediators. These results support the role of Igf1r in controlling the kinetics of cell proliferation and differentiation during pulmonary airway epithelial regeneration after injury. Overall design: Lung mRNA profiles of 3 months-old Igf1rfl/fl normal/control transgenic mice were generated by deep sequencing using Illumina GAIIx. ------------------------------------------- Submitter states "we use data on the absolute transcription levels (FPKM) of same IGF system genes on the adult "normal" mouse lung to compare them with those reported in the human adult lung (expressed in both as FPKM) (http://www.proteinatlas.org/)".
Involvement of Igf1r in Bronchiolar Epithelial Regeneration: Role during Repair Kinetics after Selective Club Cell Ablation.
Specimen part, Cell line, Subject
View SamplesMicroRNAs (miRNAs) are short noncoding RNA molecules regulating the expression of mRNAs. Target identification of miRNAs is computationally difficult due to the relatively low homology between miRNAs and their targets. We present here an experimental approach to target identification where the cartilage-specific miR-140 was overexpressed and silenced in cells it is normally expressed in separate experiments. Expression of mRNAs was profiled in both experiments and the intersection of mRNAs repressed by miR-140 overexpression and derepressed by silencing of miR-140 was identified. The intersection contained only 49 genes, although both treatments affected the accumulation of hundreds of mRNAs. These 49 genes showed a very strong enrichment for the miR-140 seed sequence implying that the approach is efficient and specific. 21 of these 49 genes were predicted to be direct targets based on the presence of the seed sequence. Interestingly, none of these were predicted by the published target prediction methods we used. One of the potential target mRNAs, Cxcl12, was experimentally validated by Northern blot analysis and a luciferase reporter assay.
Experimental identification of microRNA-140 targets by silencing and overexpressing miR-140.
No sample metadata fields
View SamplesInsight into the role of Insulin-like Growth Factor (IGF) in development of lungs has come from the study of genetically modified mice. IGF1 is a key factor during lung development. IGF1 deficiency in the neonatal mouse causes respiratory failure collapsed alveoli and altered alveolar septa. To further characterize IGF1 function during lung development we analyzed Igf1-/- mouse prenatal lungs in a C57Bl/6 genetic background. Mutant lungs showed disproportional hypoplasia, disorganized extracellular matrix and dilated alveolar capillaries. IGF1 target genes during lung maturation were identified by analyzing RNA differential expression in Igf1-/- lungs using microarrays.
Transcriptome analysis in prenatal IGF1-deficient mice identifies molecular pathways and target genes involved in distal lung differentiation.
Specimen part
View SamplesComparison of expression profile of Ewing''s sarcoma with cell of origin, mesenchymal stem cells with the goal of identifying novel therapeutic targets. Overall design: 3 Ewing''s cell lines compared to 2 MSC cell lines
Exploring the surfaceome of Ewing sarcoma identifies a new and unique therapeutic target.
No sample metadata fields
View SamplesTo determine whether an accelerated aging-like phenotype occurs in hematopoiesis of young Tif1?-/- mice (4 months old), we purified 200,000 hematopoietic stem cells (LSK: Lineage negative, Sca1+, c-Kit+) from Tif1?-/- mice and performed high-throughput mRNA sequencing (RNA-seq). We compared this transcriptome to physiological aging by creating two other RNAseq libraries from young (4 months old) and old (20 months old) wild type mice. Overall design: RNAseq study on young Tif1?-/- mice (4 months old), young wild type mice (4 months old) and old wild type mice (20 months old).
Tif1γ regulates the TGF-β1 receptor and promotes physiological aging of hematopoietic stem cells.
No sample metadata fields
View SamplesT-cell acute lymphoblastic leukemia (T-ALL) is an aggressive hematologic cancer frequently associated with activating mutations in NOTCH1. Early studies identified NOTCH1 as an attractive therapeutic target for the treatment of T-ALL through the use of gamma-secretase inhibitors (GSIs). Here, we characterized the interaction between PF-03084014, a clinically-relevant GSI, and dexamethasone in preclinical models of glucocorticoid-resistant T-ALL. Combination treatment of the GSI PF-03084014 with glucocorticoids induced a synergistic antileukemic effect in human T-ALL cell lines and primary human T-ALL patient samples. Molecular characterization of the response to PF-03084014 plus glucocorticoids through gene expression profiling revealed transcriptional upregulation of the glucocorticoid receptor as the mechanism mediating the enhanced glucocorticoid response. Moreover, treatment with PF-03084014 and glucocorticoids in combination was highly efficacious in vivo, with enhanced reduction of tumor burden in a xenograft model of T-ALL. Finally, glucocorticoid treatment was highly effective at reversing PF-03084014-induced gastrointestinal toxicity via inhibition of goblet cell metaplasia. These results suggest that combination of PF-03084014 treatment with glucocorticoids may be well-tolerated and highly active for the treatment of glucorticoid-resistant T-ALL.
Preclinical analysis of the γ-secretase inhibitor PF-03084014 in combination with glucocorticoids in T-cell acute lymphoblastic leukemia.
Cell line, Treatment
View SamplesWe report that the HF/HS-mediated functional enrichment of genes of immunity and inflammation is driven toward normal by the AOF supplementation Obesity may not constantly associate with metabolic disorders and mortality later in life, raising the challenging concept of healthy obesity. Here, high fat-high sucrose (HF/HS) feeding produces hyperglycaemia and hypercholesterolemia, increases oxidative stress, elevates endotoxemia, expands adipose tissue (with enlarged adipocytes, macrophage infiltration and accumulation of cholesterol and oxysterols), and reduces lifespan of obese mice. Despite persistence of obesity, supplementation with an antioxidant formulation normalizes plasma lipids and endotoxemia, prevents macrophage recruitment in adipose tissue, reduces adipose accumulation of cholesterol and cholesterol oxides, and extends lifespan. The HF/HS-mediated functional enrichment of genes of immunity and inflammation (in particular response to lipopolysaccharides) is driven towards normal by the antioxidant formulation. It is concluded that the limitation of immune cell infiltration in adipose tissue on the long term by an antioxidant formulation can increase lifespan independently of body weight and fat storage. It constitutes the hallmark of a healthy adiposity trait. Overall design: Examination of the expression profile of mice adipose tissues fed either standard (Std), High-fat/high-sucrose (HF/HS) or HF/HS + antioxidant formulation (AOF) for 180 days
Healthy adiposity and extended lifespan in obese mice fed a diet supplemented with a polyphenol-rich plant extract.
Age, Specimen part, Cell line, Subject
View SamplesDefining the role of epigenetic regulators in normal hematopoiesis has become critically important, as recurrent mutations or aberrant expression of these genes has been identified in both myeloid and lymphoid hematological malignancies. We have found that PRMT4, a type I arginine methyltransferase, whose function in normal and malignant hematopoiesis is unknown, is overexpressed in AML patient samples. In support of an oncogenic role for PRMT4, we find that its overexpression blocks the myeloid differentiation of human stem/progenitor cells (HSPCs) while its knockdown (KD) is sufficient to induce myeloid differentiation of HSPCs and multiple AML cell lines. Although classically thought of as a co-activator, we found that PRMT4 functions to repress the expression of miR-223 in HSPCs via the methylation of RUNX1, which triggers the assembly of a multi-protein repressor complex that includes DPF2. As part of a feedback loop, PRMT4 expression is repressed post-transcriptionally by miR-223 during the normal differentiation process. These data reveal an unidentified role of PRMT4 in myeloid differentiation and its unexpected repressive role in transcriptional regulation. Furthermore, depletion of PRMT4 results in the differentiation of myeloid leukemia cells in vitro and their decrease proliferation in vivo. Thus, targeting PRMT4 holds potential as a novel therapy for acute myelogenous leukemia. Overall design: Purified human primary CD34+ cells were transduced with lentiviruses carrying PRMT4KD or scramble control shRNAs. Total RNA was extrated. RNAseq was performed to identify target genes that are regulated by PRMT4. Experiments were performed in triplicate.
PRMT4 blocks myeloid differentiation by assembling a methyl-RUNX1-dependent repressor complex.
Specimen part, Subject
View Samples