This 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 SamplesEpidemiology studies have linked exposure to pollutant particles to increased cardiovascular mortality and morbidity, however, the mechanism remains unknown. In this study, we hypothesized that the ultrafine fraction of ambient pollutant particles would cause endothelial cells dysfunction. We profiled gene expression of human pulmonary artery endothelial cells (HPAEC) exposed to ultrafine Chapel Hill particles (UFP) (100g/ml) or vehicle for 4h with Affymetrix HG U133 Plus 2.0 chips (N = 4 each). Using an unpaired t-test (p <0.01, 5% false discovery rate) we found 426 unique genes to be differentially expressed with 320 upregulated genes and 106 downregulated genes. Among these genes, we noted upregulation of genes related to coagulation-inflammation circuitry including tissue factor (F3), coagulation factor II receptor-like 2 (F2RL2, PAR3), interleukin (IL)-6 and IL-8. Upregulation of these genes were independently confirmed by RT-PCR and/or protein release. Genes related to the CXC chemokine family that have been implicated in the pathogenesis of vascular disease were upregulated, including MCP-1 (2.60 fold), IL-8 (2.47 fold), CXCL1 (1.41 fold), CXCL2 (1.95 fold), CXCL3 (2.28 fold) and CXCR4 (1.30 fold). In addition, genes related to clotting independent signaling of F3 were also differentially expressed, including FOS, JUN and NFKBIA. Treatment of HPAEC with UFP for 16 hours increased the release of IL6 and IL8 by 1.9-fold and 1.8-fold respectively. Pretreatment of HPAEC with a blocking antibody against F3 attenuated IL6 and IL8 release by 30% and 70% respectively. Thus using gene profiling, we uncovered that UFP may induce vascular endothelial cells to express genes related to clotting and angiogenesis. These results provide a novel hypothesis that PM may cause cardiovascular adverse health effects via induction of tissue factor in vascular endothelial cells which then triggers clotting dependent and independent downstream signaling.
Up-regulation of tissue factor in human pulmonary artery endothelial cells after ultrafine particle exposure.
Treatment
View SamplesStem cell-derived tissues have wide potential for modelling developmental and pathological processes as well as cell-based therapy. However, it has proven difficult to generate several key cell types in vitro, including skeletal muscle. In vertebrates, skeletal muscles derive during embryogenesis from the presomitic mesoderm (PSM). Using PSM development as a guide to establish conditions for the differentiation of monolayer cultures of embryonic stem (ES) cells into PSM-like cells without the introduction of transgenes or cell sorting.
A Gradient of Glycolytic Activity Coordinates FGF and Wnt Signaling during Elongation of the Body Axis in Amniote Embryos.
Specimen part, Disease, Cell line, Treatment, Time
View SamplesThis SuperSeries is composed of the SubSeries listed below.
MicroRNA 144 impairs insulin signaling by inhibiting the expression of insulin receptor substrate 1 in type 2 diabetes mellitus.
Sex, Specimen part, Disease, Disease stage
View SamplesIn this study, we compared the expression profiles of miRNAs in blood samples from Impaired Fasting Glucose (IFG) and T2D male patients. Healthy adult males with no past history of T2D (n=158) and with desirable cholesterol and blood pressure profiles were enrolled in this study. They were then classified according to fasting glucose levels to have T2D, IFG or as healthy controls (CTL), for comparison of miRNA expression profiles. Employing miRNA microarray, we identified signature miRNAs in peripheral blood samples that distinguished IFG and T2D. Eight selected miRNAs were further validated using stem-loop real-time RT-PCR. miR-144 expression was found to be dysregulated in Type 2 Diabetes, wherein its expression was significantly higher than in healthy controls. Insulin receptor substrate 1 (IRS1) has been predicted to be a potential target of miR-144. Consistent with this observation, IRS1 mRNA and protein levels, verified by quantitative real-time PCR and western blotting respectively, were found to be down-regulated.
MicroRNA 144 impairs insulin signaling by inhibiting the expression of insulin receptor substrate 1 in type 2 diabetes mellitus.
Sex
View SamplesThe purpose of this study was to characterize global gene expression in human airway epithelial cells and identify cellular pathways associated with coarse, fine and ultrafine particulate matter (PM) exposures. Ambient PM was collected in 3 different size fractions from Chapel Hill air, particles were extracted from foam or filter matrices and lyophilized. Human primary airway epithelial cells were exposed to particles at 250g/ml or vehicle control for 6h in culture. Following exposure, RNA was isolated and hybridized to human HG U133A affymetrix chips.
Comparison of gene expression profiles induced by coarse, fine, and ultrafine particulate matter.
No sample metadata fields
View SamplesParathyroid hormone (PTH) plays an essential role in regulating calcium and bone homeostasis in the adult, but whether PTH is required at all for regulating fetal-placental mineral homeostasis is uncertain. To address this we treated Pth-null mice in utero with 1 nmol PTH (1-84) or saline and examined placental calcium transfer 90 minutes later. It was found that placental calcium transfer increased in Pth-null fetuses treated with PTH as compared to Pth-null fetuses treated with saline. Subsequently, to determine the effect of PTH treatment on placental gene expression, in a separate experiment, 90 minutes after the fetal injections the placentas were removed for subsequent RNA extraction and microarray analysis.
Parathyroid hormone regulates fetal-placental mineral homeostasis.
Sex, Specimen part, Treatment
View SamplesThe major type of protein arginine methyltransferase is PRMT1. Since the growth of embryos from Prmt1/ mice was arrested shortly after implantation, PRMT1 must play a critical role in early mouse development.
PRMT1 and PRMT8 regulate retinoic acid-dependent neuronal differentiation with implications to neuropathology.
Specimen part, Cell line
View SamplesPRMT1 and PRMT8 knockdown D3 embryonic stem cells were generated (siPRMT) or as a control, scrambled sequence was introduced (siSCR).
PRMT1 and PRMT8 regulate retinoic acid-dependent neuronal differentiation with implications to neuropathology.
Cell line, Treatment
View SamplesDEP exposure is linked to increases in cardiovascular effects. This effect is enhanced in individuals with pre-existing disease. Animal models of cardiovascular disease are used to study this susceptibility. The heart is rich in mitochondria, which produce high levels of free radicals, leading to inactivation of tricarboxylic acid cycle enzymes. We hypothesized that a 4-wk DEP inhalation would result in strain-related structural impairment of cardiac mitochondria and changes in these enzyme activities in WKY and SHR. Male rats (12-14 wks age) were exposed whole body to air or 0.5 or 2.0 mg/m3 DEP for 6h/d, 5 d/wk for 4 wks. Neutrophilic influx was noted in the bronchoalveolar lavage fluid in both strains. A slightly lower level of baseline cardiac mitochondrial aconitase activity was seen in SHR than WKY. Aconitase activity appeared to be decreased in an exposure related manner in both strains. Significantly higher baseline levels of cardiac cytosolic ferritin and aconitase activity were seen in the SHR than WKY. No exposure-related changes were noted in either of these measures. Mitochondrial succinate and isocitrate dehydrogenase activities were not changed following DEP exposure in either strain. Transmission electron microscopy images of the heart indicated abnormalities in cardiac mitochondria of control SHR but not control WKY. No exposure related ultrastructural changes were induced by DEP in either strain. In conclusion, strain differences in cardiac biomarkers of oxidative stress and structure of mitochondria exist between SHR and WKY. DEP exposure results in small changes in cardiac mitochondrial and cytosolic markers of oxidative stress. (Abstract does not represent USEPA policy.)
One-month diesel exhaust inhalation produces hypertensive gene expression pattern in healthy rats.
Specimen part
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