Ozone is a highly toxic air pollutant and global health concern. Mechanisms of genetic susceptibility to ozone-induced lung inflammation are not completely understood. We hypothesized Notch3 and Notch4 are important determinants of susceptibility to ozone-induced lung inflammation. Wild type (WT), Notch3 (Notch3-/-) and Notch4 (Notch4-/-) knockout mice were exposed to ozone (0.3 ppm) or filtered air for 6-72 hours. Ozone increased bronchoalveolar lavage fluid (BALF) protein, a marker of lung permeability, in all genotypes, but significantly greater concentrations were found in Notch4-/- compared to WT and Notch3-/-. Significantly greater mean numbers of BALF neutrophils were found in Notch3-/- and Notch4-/- mice compared to WT mice after ozone. Expression of whole lung Tnf was significantly increased after ozone in all genotypes, and was significantly greater in Notch3-/- mice compared to WT. Statistical analyses of the transcriptome identified differentially expressed gene networks between WT and knockout mice basally and after ozone, and included Trim30, a member of the inflammasome pathway, and Traf6, an inflammatory signaling member. These novel findings are consistent with Notch3 and Notch4 as susceptibility genes for ozone-induced lung injury, and suggest that Notch receptors protect against innate immune inflammation.
Novel Roles for Notch3 and Notch4 Receptors in Gene Expression and Susceptibility to Ozone-Induced Lung Inflammation in Mice.
Specimen part
View SamplesBackground: Nrf2 is an essential cytoprotective transcription factor. However, association of Nrf2 in organ development and neonatal disease is rarely examined. Hyperoxia exposure to newborn rodents generates pulmonary phenotypes which resemble bronchopulmonary dysplasia (BPD) of prematurity.
Targeted deletion of nrf2 impairs lung development and oxidant injury in neonatal mice.
Treatment
View SamplesRoom temperature whole blood mRNA stabilization procedures, such as the PAX gene system, are critical for the application of transcriptional analysis to population-based clinical studies. Global transcriptome analysis of whole blood RNA using microarrays has proven to be challenging due to the high abundance of globin transcripts that constitute 70% of whole blood mRNA in the blood. This is a particular problem in patients with sickle-cell disease, secondary to the high abundance of globin-expressing nucleated red blood cells and reticulocytes in the circulation . In order to more accurately measure the steady state whole blood transcriptome in sickle-cell patients, we evaluated the efficacy of reducing globin transcripts in PAXgene stabilized RNA samples for genome-wide transcriptome analyses using oligonucleotide arrays. We demonstrate here by both microarrays and Q-PCR that the globin mRNA depletion method resulted in 55-65 fold reduction in globin transcripts in whole blood collected from healthy volunteers and sickle-cell disease patients. This led to an improvement in microarray data quality with increased detection rate of expressed genes and improved overlap with the expression signatures of isolated peripheral blood mononuclear (PBMC) preparations. The differentially modulated genes from the globin depleted samples had a higher correlation coefficient to the 112 genes identified to be significantly altered in our previous study on sickle-cell disease using PBMC preparations. Additionally, the analysis of differences between the whole blood transcriptome and PBMC transcriptome reveals important erythrocyte genes that participate in sickle-cell pathogenesis and compensation. The combination of globin mRNA reduction after whole-blood RNA stabilization represents a robust clinical research methodology for the discovery of biomarkers for hematologic diseases and in multicenter clinical trials investigating a wide range of nonhematologic disorders where fractionation of cell types is impracticable.
Characterization of whole blood gene expression profiles as a sequel to globin mRNA reduction in patients with sickle cell disease.
Specimen part, Subject
View SamplesIn sickle cell disease, ischemia-reperfusion injury and intravascular hemolysis produce endothelial dysfunction and vasculopathy characterized by reduced nitric oxide (NO) and arginine bioavailability. Recent functional studies of platelets in patients with sickle cell disease reveal a basally activated state, suggesting that pathological platelet activation may contribute to sickle cell disease vasculopathy. Studies were therefore undertaken to examine transcriptional signaling pathways in platelets that may be dysregulated in sickle cell disease. We demonstrate and validate here the feasibility of comparative platelet transcriptome studies on clinical samples from single donors, by the application of RNA amplification followed by microarray-based analysis of 54,000 probe sets. Data mining an existing microarray database, we identified 220 highly abundant genes in platelets and a subset of 72 relatively platelet-specific genes, defined by more than 10-fold increased expression compared to the median of other cell types in the database with amplified transcripts. The highly abundant platelet transcripts found in the current study included 82% or 70% of platelet abundant genes identified in two previous gene expression studies on non-amplified mRNA from pooled or apheresis samples, respectively. On comparing the platelet gene expression profiles in 18 patients with sickle cell disease in steady state to 12 African American controls, at a 3-fold cut-off and 5% false discovery rate, we identified ~100 differentially expressed genes, including multiple genes involved in arginine metabolism and redox homeostasis. Further characterization of these pathways using real time PCR and biochemical assays revealed increased arginase II expression and activity and decreased platelet polyamine levels. These studies suggest a potential pathogenic role for platelet arginase and altered arginine and polyamine metabolism in sickle cell disease and provide a novel framework for the study of disease-specific platelet biology.
Amplified expression profiling of platelet transcriptome reveals changes in arginine metabolic pathways in patients with sickle cell disease.
Specimen part
View SamplesRationale: Neonatal mice have the capacity to regenerate their hearts in response to injury, but this potential is lost after the first week of life. The transcriptional changes that underpin mammalian cardiac regeneration have not been fully characterized at the molecular level. Objective: The objectives of our study were to determine if myocytes revert the transcriptional phenotype to a less differentiated state during regeneration and to systematically interrogate the transcriptional data to identify and validate potential regulators of this process. Methods and Results: We derived a core transcriptional signature of injury-induced cardiac myocyte regeneration in mouse by comparing global transcriptional programs in a dynamic model of in vitro and in vivo cardiac myocyte differentiation, in vitro cardiac myocyte explant model, as well as a neonatal heart resection model. The regenerating mouse heart revealed a transcriptional reversion of cardiac myocyte differentiation processes including reactivation of latent developmental programs similar to those observed during de-stabilization of a mature cardiac myocyte phenotype in the explant model. We identified potential upstream regulators of the core network, including interleukin 13 (IL13), which induced cardiac myocyte cell cycle entry and STAT6/STAT3 signaling in vitro. We demonstrate that STAT3/periostin and STAT6 signaling are critical mediators of IL13 signaling in cardiac myocytes. These downstream signaling molecules are also modulated in the regenerating mouse heart. Conclusions: Our work reveals new insights into the transcriptional regulation of mammalian cardiac regeneration and provides the founding circuitry for identifying potential regulators for stimulating heart regeneration. Overall design: Comparison of transcriptional programs of primary myocardial tissues sampled from neonatal mice and murine hearts undergoing post-injury regeneration, along with in vitro ESC-differentiated cardiomyocytes
Transcriptional reversion of cardiac myocyte fate during mammalian cardiac regeneration.
No sample metadata fields
View SamplesLiposarcoma is a poorly understood malignancy of fat cells. Lipolysis, a central pathway of adipose tissue metabolism, has been implicated in cancer. Here, we generated tissue-specific single- and combined knockout mice for the two major lipases ATGL and HSL. Notably, double knockout (DAKO) mice developed late onset liposarcoma with complete penetrance, while single knockout mice appeared normal. DAKO whole transcriptome profiles differed from those of single knockout mice, revealing an early-onset tissue-specific response that persisted until the late-onset development of liposarcoma. Cancer-associated markers Gpnmb and G0s2 were among the most highly dysregulated genes in DAKO mice and also in human liposarcomas, suggesting a potential role for these proteins as liposarcoma-specific biomarkers. Taken together, our results demonstrate a novel epistatic interaction linking lipolysis with cancer. DAKO mice provide a promising model for studying early premalignant changes that lead to late-onset disease.
Epistatic interaction between the lipase-encoding genes Pnpla2 and Lipe causes liposarcoma in mice.
Age, Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
A condensin-like dosage compensation complex acts at a distance to control expression throughout the genome.
No sample metadata fields
View SamplesIn many species, a dosage compensation complex (DCC) is targeted to X chromosomes of one sex to equalize levels of X gene products between males (1X) and females (2X). Here we identify cis-acting regulatory elements that target the C. elegans X chromosome for repression by the DCC. The DCC binds to discrete, dispersed sites on X of two types. rex sites recruit the DCC in an autonomous, DNA sequence-dependent manner using a 12 bp consensus motif that is enriched on X. This motif is critical for DCC binding, is clustered in rex sites, and confers much of X-chromosome specificity. Motif variants enriched on X by 3.8-fold or more are highly predictive (95%) for rex sites. In contrast, dox sites lack the X-enriched variants and cannot bind the DCC when detached from X. dox sites are more prevalent than rex sites and, unlike rex sites, reside preferentially in promoters of some expressed genes. These findings fulfill predictions for a targeting model in which the DCC binds to recruitment sites on X and disperses to discrete sites lacking autonomous recruitment ability. To relate DCC binding to function, we identified dosage-compensated and non-compensated genes on X. Unexpectedly, many genes of both types have bound DCC, but many do not, suggesting the DCC acts over long distances to repress X gene expression. Remarkably, the DCC binds to autosomes, but at far fewer sites and rarely at consensus motifs. DCC disruption causes opposite effects on expression of X and autosomal genes. The DCC thus acts at a distance to impact expression throughout the genome.
A condensin-like dosage compensation complex acts at a distance to control expression throughout the genome.
No sample metadata fields
View SamplesAblative RT results in increased expression of CCL2 within the tumor microenvironment of pancreatic ductal adenocarcinoma (PDAC) and also increased recruitment of CD45+CD11b+Ly6Chi inflammatory monocytes/macrophages. This increase in CCL2 expression and recruitment of inflammatory monocytes/macrophages is a mechanism of resistance to the anti-tumor effects of ablative radiotherapy (RT).
Tumor-Derived CCL2 Mediates Resistance to Radiotherapy in Pancreatic Ductal Adenocarcinoma.
Sex, Age
View SamplesSelenium has cancer preventive activity that is mediated, in part, through selenoproteins. The role of the 15 kDa selenoprotein (Sep15) in colon cancer was assessed by preparing and using mouse colon CT26 cells stably transfected with shRNA constructs targeting Sep15. Metabolic 75Se-labeling and Northern and Western blot analyses revealed that more than 90% of Sep15 was knocked down. Growth of the resulting Sep15-deficient CT26 cells was reduced (p<0.01) and cells formed significantly (p<0.001) fewer colonies in soft agar compared to control CT26 cells. Whereas most (14/15) BALB/c mice injected with control cells developed tumors, few (3/30) mice injected with Sep15 knockdown cells developed tumors (p<0.0001). The ability to form pulmonary metastases had similar results. Mice injected with the plasmid-transfected control cells had >250 lung metastases/mouse; however, mice injected with the Sep15 knockdown cells only had 7.8 +/- 5.4 metastases. To investigate molecular targets affected by Sep15 status, gene expression patterns between control and knockdown CT26 cells were compared. Ingenuity Pathways Analysis was used to analyze the 1045 genes that were significantly (p<0.001) affected by Sep15 deficiency. The highest scored biological functions were cancer and cellular growth and proliferation. Consistent with these observations, subsequent analyses revealed a G2/M cell cycle arrest in Sep15 CT26 knockdown cells. In contrast, to CT26 cells Sep15 knockdown in Lewis Lung Carcinoma (LLC1) cells did not affect anchorage-dependent or independent cell growth. These data suggest tissue specificity in the cancer protective effects of Sep15 knockdown, which are mediated, at least in part, by influencing the cell cycle.
Deficiency in the 15-kDa selenoprotein inhibits tumorigenicity and metastasis of colon cancer cells.
Specimen part, Cell line
View Samples