Study on selective vulnerability of certain brain regions to oxidative stress. Here we selected 4 brain regions (hippocampal CA1 and CA3, cerebral cortex, and cerebellar granular layer) to study this phenomenon.
Genomic and biochemical approaches in the discovery of mechanisms for selective neuronal vulnerability to oxidative stress.
Specimen part
View SamplesMechanistic study on the differential responses of the two hippocampal adjoining regions, i.e., CA1 and CA3, to elevated oxidative stress.
Genome-wide transcriptome profiling of region-specific vulnerability to oxidative stress in the hippocampus.
No sample metadata fields
View SamplesWe used microarrays to determine global gene expression in primary tumor tissues (ESCC) and matched normal tissues (adjacent normal esophageal mucosa)
Hypoxia activates the cyclooxygenase-2-prostaglandin E synthase axis.
Sex, Age, Specimen part
View SamplesTo delineate the role of hypoxia in esophageal epithelial biology, we carried out gene array experiments using a non-transformed immortalized diploid human esophageal cell line, EPC2-hTERT (Mol Cancer Res. 2003;1:729-38). Unlike cancer cell lines, EPC2-hTERT has no genetic alterations at early passages that may affect the cellular response to hypoxia.
Hypoxia activates the cyclooxygenase-2-prostaglandin E synthase axis.
No sample metadata fields
View SamplesGlud1 (Glutamate dehydrogenase 1) transgenic mice release more excitatory neurotransmitter glutamate to synaptic cleft throughout lifespan.
Gene expression patterns in the hippocampus during the development and aging of Glud1 (Glutamate Dehydrogenase 1) transgenic and wild type mice.
Specimen part
View SamplesGonadotrope or null cell pituitary tumors present clinically with signs of hypogonadism and hypopituitarism, together with visual disturbances due to mass effects. Since there are no medical therapies, surgery and/or radiation are the only therapeutic options. To identify dysregulated genes and/or pathways that may play a role in tumorigenesis and/ or progression, molecular profiling was performed on 14 gonadotrope tumors and 9 normal human pituitaries from autopsy samples. Principle component analysis (PCA) revealed clear discrimination between tumor and normal pituitary gene expression profiles. Bioinformatic analysis identified specific genes and pathways that were highly differentially regulated, including a cohort of putative downstream effectors of p53 were repressed in gonadotrope pituitary tumors, including GADD45, GADD45 and Reprimo with concomitant downregulation of the upstream regulator, PLAGL1. PLAGL1 reexpression in gonadotrope cells did not directly modulate the downstream targets. Further functional analysis of GADD45 was performed. Overexpression of GADD45 in mouse gonadotrope cells blocked proliferation, increased rates of apoptosis in response to growth factor withdrawal and increased colony formation in soft agar. In contrast to prior studies with GADD45, methylation interference assays showed no evidence of epigenetic modification of the GADD45 promoter in pituitary tumors. Thus, our data suggest that many components downstream of p53 are suppressed in gonadotrope pituitary tumors. A novel candidate, GADD45 is low in tumors and reexpression blocks proliferation, survival and tumorigenesis in gonadotrope cells. Unlike GADD45, GADD45 is not methylated to block its expression. Together these studies identify new targets and mechanisms to explore concerning pituitary tumor initiation and progression.
Identification of growth arrest and DNA-damage-inducible gene beta (GADD45beta) as a novel tumor suppressor in pituitary gonadotrope tumors.
Sex
View SamplesAn important but largely unmet challenge in understanding the mechanisms that govern formation of specific organs is to decipher the complex and dynamic genetic programs exhibited by the diversity of cell types within the tissue of interest. Here, we use an integrated genetic, genomic and computational strategy to comprehensively determine the molecular identities of distinct myoblast subpopulations within the Drosophila embryonic mesoderm at the time that cell fates are initially specified. A compendium of gene expression profiles was generated for primary mesodermal cells purified by flow cytometry from appropriately staged wild-type embryos and from twelve genotypes in which myogenesis was selectively and predictably perturbed. A statistical meta-analysis of these pooled datasetsbased on expected trends in gene expression and on the relative contribution of each genotype to the detection of known muscle genesprovisionally assigned hundreds of differentially expressed genes to particular myoblast subtypes. Whole embryo in situ hybridizations were then used to validate the majority of these predictions, thereby enabling true positive detection rates to be estimated for the microarray data. This combined analysis reveals that myoblasts exhibit much greater gene expression heterogeneity and overall complexity than was previously appreciated. Moreover, it implicates the involvement of large numbers of uncharacterized, differentially expressed genes in myogenic specification and subsequent morphogenesis. These findings also underscore a requirement for considerable regulatory specificity for generating diverse myoblast identities. Finally, to illustrate how the developmental functions of newly identified myoblast genes can be efficiently surveyed, a rapid RNA interference assay that can be scored in living embryos was developed and applied to selected genes. This integrated strategy for examining embryonic gene expression and function provides a substantially expanded framework for further studies of this model developmental system.
An integrated strategy for analyzing the unique developmental programs of different myoblast subtypes.
No sample metadata fields
View SamplesWe sequenced mRNA from a total of 12 samples (6 different cell types, each with two biological replicates) to infer the relationship among those cell types Overall design: Examination of mRNA levels in six different human cell types grown in culture with two biological replicates for each cell type
Cell-type phylogenetics and the origin of endometrial stromal cells.
No sample metadata fields
View SamplesBACKGROUND: miRNA have been shown to play an important role during immune-mediated diseases such as inflammatory bowel disease. The aim of this study was to assess differential expression of miRNA between uninfected and infected mice with Clostridium difficile strain VPI 10463 RESULTS: MicroRNA (miRNA)-sequencing analysis indicated that miR-146b, miR-1940, and miR-1298 were significantly overexpressed in colons of C. difficile-infected mice Overall design: Colon of uninfected and C.difficile-infected C57BL6/J WT mice were sampled at day 4 post-infection with Clostridium difficile VPI 10463. The infection dose was 107 cfu/mouse.
Modeling the role of peroxisome proliferator-activated receptor γ and microRNA-146 in mucosal immune responses to Clostridium difficile.
Specimen part, Cell line, Subject
View SamplesDevelopment, growth and adult survival are coordinated with available metabolic resources. The insulin/IGF and TOR signaling pathways relay nutritional status, thereby ascertaining that the organism responds appropriately to environmental conditions. MicroRNAs are short (21-23 nt) regulatory RNAs that confer specificity on the RNA-induced silencing complex (RISC) to inhibit a given set of mRNA targets. We profiled changes in miRNA expression during adult life in Drosophila melanogaster and determined that miR-277 is down-regulated with age. This miRNA controls branched-chain amino acid (BCAA) catabolism and the activity of the TOR kinase, a central growth regulator. Metabolite analysis suggests that the mechanistic basis may be an accumulation of BCKAs, rather than BCAAs, thus avoiding potentially detrimental consequences of increased branched chain amino acid levels on e.g. translational fidelity. Constitutive miR-277 expression as well as transgenic inhibition with a miRNA sponge construct shortens lifespan. Furthermore, constitutive miR-277 expression is synthetically lethal with reduced insulin signaling. Thus, optimal metabolic adaptation requires tuning of cellular BCAA catabolism by miR-277 to be concordant with systemic growth signaling. Overall design: Transgenic Drosophila melanogaster fruitflies carrying strong, ubiquitously expressed pre-miR277 hairpins (wt and two mutant versions) were dissected, total RNA was extracted from the abdomen and gel-purified for size selection (~18-30 nt). Digested plasmid samples were compared to those of circular plasmids and a nontransfected control. The purpose of this experiment was to demonstrate the extent of expression from mutant pre-miR277 hairpins, mut1 should abolish Drosha-processing while mut2 is conservative.
Drosophila miR-277 controls branched-chain amino acid catabolism and affects lifespan.
Specimen part, Subject
View Samples