This SuperSeries is composed of the SubSeries listed below.
Metabolomic Identification of Subtypes of Nonalcoholic Steatohepatitis.
Age, Specimen part, Treatment
View SamplesMethionine adenosyltransferase (MAT) enzymes generate SAMe (S-adenosylmethionine), the main biological methyl donor. There are two MAT encoding genes in mammals (Mat1a and Mat2a), which show different activities and cellular distribution. Mat1a encodes the enzyme mainly expressed in normal liver. Mat1a ablation in mice results in the spontaneous development of non-alcoholic steatohepatitis (NASH). We observed that SAMe depletion in Mat1a KO mice had three main effects on hepatic lipid metabolism: 1) impaired TG (triglyceride) export via VLDL; 2) impaired mitochondrial FA (fatty acid) oxidation (as evidenced by membrane depolarization, downregulation of Phb1 (prohibitin 1, a mitochondrial chaperone protein) and Mcj/Dnajc15 (endogenous mitochondrial repressor of respiratory chain), and accumulation of long-chain acylcarnitines); and 3) increased FA uptake. The convergence of these three factors induced TG accumulation in LD (lipid droplets). LD expansion confronts hepatocytes with a high demand of PC (phosphatidylcholine) molecules to cover the LD surface since other phospholipids, such as PE (phosphatidylethanolamine), cannot stabilize LD and prevent coalescence. In Mat1a KO this situation is aggravated, since SAMe-dependent PC synthesis via PE methylation is decreased, the PC/PE ratio reduced and mitochondrial FA oxidation impaired. To put a brake to this drain of PC molecules to LD, FA are rerouted in Mat1a KO mice liver to other catabolic (endoplasmic reticulum and peroxisome oxidation) and biosynthetic (ceramides synthesis) pathways, causing oxidative stress, inflammation and fibrosis. SAMe treatment for two months in 8-9 month old Mat1a KO mice ameliorated mitochondrial dysfunction (reduces membrane depolarization, improves Phb1 and Mcj expression, and increases SAMe transport to mitochondria) improving FA oxidation efficiency (FA and acylcarnitine levels decrease), which results in a drastic reduction in TG accumulation. SAMe treatment in Mat1a KO mice resulted in more PC available for proper membrane function, improving liver lipid homeostasis, histology (H&E, Sudan red, Sirius red) and liver injury (ALT, AST).
Metabolomic Identification of Subtypes of Nonalcoholic Steatohepatitis.
Age, Specimen part
View SamplesPatients with systemic lupus erythematosus (SLE) have a markedly increased risk to develop cardiovascular disease, and traditional cardiovascular risk factors fail to account for this increased risk. We used microarray to probe the platelet transcriptome in individuals with SLE and healthy controls, and the gene and protein expression of a subset of differentially expressed genes was further investigated and correlated to platelet activation status. Real-time PCR was used to confirm a type I interferon (IFN) gene signature in patients with SLE, and the IFN-regulated proteins PRKRA, IFITM1 and CD69 (p<0.0001) were found to be up-regulated in platelets from SLE patients as compared to healthy volunteers. Notably, patients with a history of vascular disease had increased expression of type I IFN-regulated proteins as well as more activated platelets as compared with patients without vascular disease. We suggest that interferogenic immune complexes stimulate production of IFN which up-regulates the megakaryocytic type I IFN-regulated genes and proteins. This could affect platelet activation and contribute to development of vascular disease in SLE. In addition, platelets with type I IFN signature could be a novel marker for vascular disease in SLE.
Platelet transcriptional profile and protein expression in patients with systemic lupus erythematosus: up-regulation of the type I interferon system is strongly associated with vascular disease.
Sex, Age, Specimen part, Disease
View SamplesThe highly conserved Epidermal Growth Factor-receptor (Egfr) pathway is required in all animals for normal development and homeostasis; consequently, aberrant Egfr signaling is implicated in a number of diseases. Genetic analysis of Drosophila melanogaster Egfr has contributed significantly to understanding this conserved pathway and has led to the discovery of new components and targets. Here we used microarray analysis of Drosophila third instar wing discs, in which Egfr signaling was perturbed, to identify new Egfr-responsive genes. Upregulated transcripts included five known targets suggesting the approach was valid. We investigated the function of 29 previously uncharacterized genes, which had pronounced responses. The Egfr pathway is important for wing-vein patterning and using reverse genetic analysis we identified five genes that showed venation defects. Three of these genes are expressed in vein primordia and all showed transcriptional changes in response to altered Egfr activity consistent with being targets of the pathway. Genetic interactions with Egfr further linked two of the genes, Sulfated (Sulf1), an endosulfatase gene, and CG4096, an ADAMTS (A Disintegrin And Metalloproteinase with ThromboSpondin motifs) gene, to the pathway. Sulf1 showed a strong genetic interaction with the neuregulin-like ligand vein (vn) and may influence binding of Vn to heparan-sulfated proteoglycans (HSPGs). Genetic evidence also shows that CG4096 functions by modulating activity of the Egfr ligands. The substrate(s) and how ligand activity is affected are unknown, but interestingly vertebrate EGF ligands are regulated by a related ADAMTS protein. We conclude Sulf1 and CG4096 are negative feedback regulators of Egfr signaling that function in the extracellular space to influence ligand activity.
New negative feedback regulators of Egfr signaling in Drosophila.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Epigenetic Networks Regulate the Transcriptional Program in Memory and Terminally Differentiated CD8+ T Cells.
Specimen part, Treatment
View SamplesEpigenetic mechanisms play a critical role during differentiation of T cells by contributing to the formation of stable and heritable transcriptional patterns. To further study the mechanisms of memory maintenance in CD8+ T cells, we performed genome-wide analysis of DNA methylation, histone marking (H3K9Ac and H3K9me3) and gene expression profiles in naive, effector memory (EM) and terminally differentiated memory (TEMRA) cells. Our results indicate that DNA demethylation and histone acetylation are coordinated to generate the transcriptional program associated with memory cells. Conversely, EM and TEMRA cells share a very similar epigenetic landscape. Nonetheless, the TEMRA transcriptional program predicts an innate immunity phenotype associated with genes never reported in these cells, including several mediators of NK cell activation (VAV3 and LYN) and a large array of NK receptors (KIR2DL3, KIR2DL4, KIR2DL1, KIR3DL1, KIR2DS5, etc.). In addition, we identified up to 161 genes that encode transcriptional regulators, some of unknown function in CD8+ T cells, that were differentially expressed in the course of differentiation. Overall, these results provide new insights into the regulatory networks involved in memory CD8+ T cell maintenance and T cell terminal differentiation.
Epigenetic Networks Regulate the Transcriptional Program in Memory and Terminally Differentiated CD8+ T Cells.
Specimen part
View SamplesEpigenetic mechanisms play a critical role during differentiation of T cells by contributing to the formation of stable and heritable transcriptional patterns. To further study the mechanisms of memory maintenance in CD8+ T cells, we performed genome-wide analysis of DNA methylation, histone marking (H3K9Ac and H3K9me3) and gene expression profiles in naive, effector memory (EM) and terminally differentiated memory (TEMRA) cells. Our results indicate that DNA demethylation and histone acetylation are coordinated to generate the transcriptional program associated with memory cells. Conversely, EM and TEMRA cells share a very similar epigenetic landscape. Nonetheless, the TEMRA transcriptional program predicts an innate immunity phenotype associated with genes never reported in these cells, including several mediators of NK cell activation (VAV3 and LYN) and a large array of NK receptors (KIR2DL3, KIR2DL4, KIR2DL1, KIR3DL1, KIR2DS5, etc.). In addition, we identified up to 161 genes that encode transcriptional regulators, some of unknown function in CD8+ T cells, that were differentially expressed in the course of differentiation. Overall, these results provide new insights into the regulatory networks involved in memory CD8+ T cell maintenance and T cell terminal differentiation.
Epigenetic Networks Regulate the Transcriptional Program in Memory and Terminally Differentiated CD8+ T Cells.
Specimen part, Treatment
View SamplesMicroRNAs predominantly decrease gene expression; however, specific mRNAs are translationally upregulated in quiescent (G0) mammalian cells and immature Xenopus laevis oocytes by an FXR1a-associated microRNP (microRNA-protein complex) that lacks the microRNP repressor, GW182. We conducted global proteomic analysis in THP1 cells depleted of FXR1 to globally identify activation targets of more than one microRNA, since FXR1 is required for microRNAmediated translation activation in THP1 G0 cells by FXR1-microRNPs.Since proteomic data changes could also be due to changes at the RNA level, total RNA levels in FXR1knockdown compared to control shRNA cells were examined in parallel by microarray analysis using Affymetrix Human GeneChip 2.0 ST.
A Specialized Mechanism of Translation Mediated by FXR1a-Associated MicroRNP in Cellular Quiescence.
Specimen part, Cell line
View SamplesCharacterization of the gene expression profiles of specific cell populations of the human urinary bladder provides an important set of research tools for the study of cellular differentiation and the cancer process. The transcriptome is a definitive identifier of each individual cell types. Surgically resected tissue was digested by collagenase and the different cell types were sorted by antibodies to cluster designation (CD) cell surface antigens. The sorted cells were analyzed by DNA microarrays. The transcriptome datasets were analyzed for differentially expressed genes and plotted on a principal components analysis space for cell lineage relationship. The following bladder cell types were analyzed: CD9+ urothelial, CD104+ basal, CD13+ stromal of lamina propria, CD9+ urothelial carcinoma cancer, and CD13+ urothelial carcinoma-associated stromal. Gene expression differences between the cell types of tumor and their respective non-cancer counterpart provide biomarker candidates. Basal cells of the bladder and prostate, although sharing CD cell surface markers, are quite different in overall gene expression. Furthermore, these cells lack transcript features of stem cell signature of embryonic stem or embryonal carcinoma cells. Cell type-specific transcriptomes are more informative than bulk tissue transcriptomes. The relatedness of different cell types can be determined by transcriptome dataset comparison.
Bladder expression of CD cell surface antigens and cell-type-specific transcriptomes.
Specimen part
View SamplesLuminal, basal, stromal, and endothelial cells were MACS sorted from whole tissue. Targets from five biological replicates of each were generated and the expression profiles were determined using Affymetrix U133 Plus 2.0 arrays. These data represent cell specific transcriptomes.
Transcriptomes of human prostate cells.
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