Hexose-6-phosphate dehydrogenase (H6PD)is the initial component of a pentose phosphate pathway inside the endoplasmic reticulum (ER) that generates NADPH for ER enzymes. In liver, H6PD is required for the 11-oxoreductase activity of 11ss-hydroxysteroid dehydrogenase type 1 (11ss-HSD1), which converts inactive 11-oxo glucocorticoids to their active 11-hydroxyl counterparts; consequently, H6PD null mice are relatively insensitive to glucocorticoids, exhibiting fasting hypoglycemia, increased insulin sensitivity despite elevated circulating levels of corticosterone, and increased basal and insulin-stimulated glucose uptake in muscles normally enriched in Type II (fast) fibers which have increased glycogen content. They also display a progressive vacuolar myopathy evident after 4 weeks of age.
Deletion of hexose-6-phosphate dehydrogenase activates the unfolded protein response pathway and induces skeletal myopathy.
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View SamplesStudy the training exercise effects in chronic obstructive pulmonary disease (COPD) patients and aged-matched healthy individuals. Skeletal muscle biopsies from 9 stable COPD patients with normal fat free mass index (FFMI, 21Kg/m2) (COPDN), 6 COPD patients with low FFMI (16Kg/m2) (COPL), and 12 healthy sedentary subjects (FFMI 21Kg/m2) before and after 8 weeks of a supervised endurance exercise program were analyzed.
A systems biology approach identifies molecular networks defining skeletal muscle abnormalities in chronic obstructive pulmonary disease.
Specimen part, Disease, Disease stage, Subject
View SamplesThe aim of our study was to identify gene expression profiles of ductal and lobular carcinomas in relation to normal ductal and lobular cells. We examined ten mastectomy specimens from postmenopausal breast cancer patients. Ductal and lobular tumor and normal cells were microdissected from cryosections. Fifty nanograms of total RNA were amplified and labeled by PCR and in vitro transcription. GCOS pairwise comparison algorithm and rank products have identified multiple genes that are differentially expressed in comparisons between ductal and lobular tumor and normal cell types. The results suggest that these genes are involved in epithelial-mesenchymal transition, TGFbeta and Wnt signaling. These changes are present in both tumor types but appear to be more prominent in lobular carcinomas.
Novel markers for differentiation of lobular and ductal invasive breast carcinomas by laser microdissection and microarray analysis.
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View SamplesProgressive failure of insulin-producing beta cells is the central event leading to diabetes, yet the signalling networks controlling beta cell fate remain poorly understood. Here we show that SRp55, a splicing factor regulated by the diabetes susceptibility gene GLIS3, has a major role in maintaining function and survival of human beta cells. RNA-seq analysis revealed that SRp55 regulates the splicing of genes involved in cell survival and death, insulin secretion and JNK signalling. Specifically, SRp55-mediated splicing changes modulate the function of the pro-apoptotic proteins BIM and BAX, JNK signalling and endoplasmic reticulum stress, explaining why SRp55 depletion triggers beta cell apoptosis. Furthermore, SRp55 depletion inhibits beta cell mitochondrial function, explaining the observed decrease in insulin release. These data unveil a novel layer of regulation of human beta cell function and survival, namely alternative splicing modulated by key splicing regulators such as SRp55 that may crosstalk with candidate genes for diabetes. Overall design: Five independent preparations of EndoC-ßH1 cells exposed to control (siCTL) or SRp55 (siSR#2) siRNAs
SRp55 Regulates a Splicing Network That Controls Human Pancreatic β-Cell Function and Survival.
Treatment, Subject
View SamplesMost hepatocellular carcinomas in younger patients from Peru arise from non-cirrhotic livers. Histological examination of the non-tumor liver tissues highlights the presence of clear cell foci in a significant fraction of Peruvian patients with hepatocellular carcinoma.
Liver clear cell foci and viral infection are associated with non-cirrhotic, non-fibrolamellar hepatocellular carcinoma in young patients from South America.
Specimen part, Disease stage, Subject
View SamplesDespite widespread use of sunscreens that minimize erythema by blocking ultraviolet B (UVB) radiation, incidence rates of melanoma continue to rise. In considering this disparity between intervention and disease prevalence, we investigated the in vivo transcriptome of human skin treated with sunscreen and solar-simulated radiation (ssR). A focal skin area of healthy participants was exposed to ssR at 1 minimal erythema dose (MED), 0.1 MED or 100 J/m2 with or without prior application of sunscreen, or to non-UVB-spectrum of ssR (solar-simulated UVA/visible/infrared radiation: ssA). Skin biopsies were analyzed using expression microarrays.
Transcriptional signatures of full-spectrum and non-UVB-spectrum solar irradiation in human skin.
Sex, Specimen part
View SamplesPancreatic beta-cell dysfunction and death are central in the pathogenesis of type 2 diabetes. Saturated fatty acids cause beta-cell failure and contribute to diabetes development in genetically predisposed individuals. Here we used RNA-sequencing to map transcripts expressed in five palmitate-treated human islet preparations, observing 1,325 modified genes. Palmitate induced fatty acid metabolism and endoplasmic reticulum (ER) stress. Functional studies identified novel mediators of adaptive ER stress signaling. Palmitate modified genes regulating ubiquitin and proteasome function, autophagy and apoptosis. Inhibition of autophagic flux and lysosome function contributed to lipotoxicity. Palmitate inhibited transcription factors controlling beta-cell phenotype including PAX4 and GATA6. 59 type 2 diabetes candidate genes were expressed in human islets, and 11 were modified by palmitate. Palmitate modified expression of 17 splicing factors and shifted alternative splicing of 3,525 transcripts. Ingenuity Pathway Analysis of modified transcripts and genes confirmed that top changed functions related to cell death. DAVID analysis of transcription binding sites in palmitate-modified transcripts revealed a role for PAX4, GATA and the ER stress response regulators XBP1 and ATF6. This human islet transcriptome study identified novel mechanisms of palmitate-induced beta-cell dysfunction and death. The data point to crosstalk between metabolic stress and candidate genes at the beta-cell level. Overall design: 5 human islet of Langerhans preparations examined under 2 conditions (control and palmitate treatment)
RNA sequencing identifies dysregulation of the human pancreatic islet transcriptome by the saturated fatty acid palmitate.
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View SamplesHigh expression of the ETS family transcription factor ERG is associated with poor clinical outcome in acute myeloid leukemia (AML) and acute T-cell lymphoblastic leukemia (T-ALL). In murine models, high ERG expression induces both T-ALL and AML. However, no study to date has defined the effect of high ERG expression on primary human hematopoietic cells. In the present study, human CD34+ cells were transduced with retroviral vectors to elevate ERG gene expression to levels detected in high ERG AML. RNA sequencing was performed on purified populations of transduced cells to define the effects of high ERG on gene expression in human CD34+ cells. Integration of the genome-wide expression data with other data sets revealed that high ERG drives an expression signature that shares features of normal hematopoietic stem cells, high ERG AMLs, early T-cell precursor-ALLs and leukemic stem cell signatures associated with poor clinical outcome. Functional assays linked this gene expression profile to enhanced progenitor cell expansion. These results support a model whereby a stem cell gene expression network driven by high ERG in human cells enhances the expansion of the progenitor pool, providing opportunity for the acquisition and propagation of mutations and the development of leukemia. Overall design: RNA sequencing in ERG overexpressing human CD34+ cells
Overexpression of ERG in cord blood progenitors promotes expansion and recapitulates molecular signatures of high ERG leukemias.
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View SamplesEfferent inhibition of cochlear outer hair cells is mediated by nicotinic cholinergic receptors containing alpha9 (a9) and alpha10 subunits. Mice lacking a9 nicotinic subunits fail to exhibit classic olivocochlear responses and are characterized by abnormal synaptic morphology at the base of outer hair cells. To detail molecular changes induced upon the loss of a9 subunit, we sampled cochlear RNA from wild type and a9 null mice at postnatal (P) days spanning periods of synapse formation and maturation (P3, P7, P13 and P60). Our findings point to a delay in cochlear maturation starting at the onset of hearing (P13), as well as an up-regulation of various GABA receptor subunits in adult mice lacking the a9 nicotinic subunit.
Lack of nAChR activity depresses cochlear maturation and up-regulates GABA system components: temporal profiling of gene expression in alpha9 null mice.
Specimen part
View SamplesA fundamental challenge in genomics is to map DNA sequence variants onto changes in gene expression. Gene expression is regulated by cis-regulatory elements (CREs, i.e., enhancers, promoters, and silencers) and the trans factors (e.g., transcription factors) that act upon them. A powerful approach to dissecting cis and trans effects is to compare F1 hybrids with F0 homozygotes. Using this approach and taking advantage of the high frequency of polymorphisms in wild-derived inbred Cast/EiJ mice relative to the reference strain C57BL/6J, we conducted allele-specific mRNA-seq analysis in the adult mouse retina, a disease-relevant neural tissue. We found that cis effects account for the bulk of gene regulatory divergence in the retina. Many CREs contained functional (i.e., activating or silencing) cis-regulatory variants mapping onto altered expression of genes, including genes associated with retinal disease. By comparing our retinal data with previously published liver data, we found that most of the cis effects identified were tissue-specific. Lastly, by comparing reciprocal F1 hybrids, we identified evidence of imprinting in the retina for the first time. Our study provides a framework and resource for mapping cis-regulatory variants onto changes in gene expression, and underscores the importance of studying cis-regulatory variants in the context of retinal disease. Overall design: Retinas from four classes of 8 week old male mice were collected: F0 C57BL/6J (B6), F0 Cast/EiJ (Cast), F1 B6xCast, and F1 CastxB6. Three replicates per class were generated. Each replicate consisted of a pool of 6-8 retinas. The mRNA-seq was conducted with paired-end 2x101 sequencing on the Illumina HiSeq 2000 platform. One lane of sequencing was run for all twelve samples. An additional lane of sequencing was run for the six F1 samples.
Hybrid mice reveal parent-of-origin and Cis- and trans-regulatory effects in the retina.
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