Progressive 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 SamplesWe performed microarray analysis to evaluate differences in the transcriptome of type 2 diabetic human islets compared to non-diabetic islet samples.
Class II phosphoinositide 3-kinase regulates exocytosis of insulin granules in pancreatic beta cells.
Sex, Age, Specimen part, Disease, Disease stage
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.
No sample metadata fields
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LRH-1 agonism favours an immune-islet dialogue which protects against diabetes mellitus.
Age, Specimen part, Treatment
View SamplesStrategy to repress autoimmunity and promote islet beta cell regeneration
LRH-1 agonism favours an immune-islet dialogue which protects against diabetes mellitus.
Age, Specimen part, Treatment
View SamplesChronic lymphocytic leukemia (CLL) is a disorder of mature B cells. Most patients are characterized by indolent disease and an anergic phenotype of their leukemia cells which refers to a state of unresponsiveness to B cell receptor stimulation. Using the E-TCL1 mouse model, we show that B cell-specific ablation of NFAT2 leads to the loss of the anergic phenotype culminating in a significantly compromised life expectancy and histological transformation to aggressive disease. We further define a gene expression signature of anergic CLL cells consisting of several NFAT2-dependant genes employing microarray technology.
NFAT2 is a critical regulator of the anergic phenotype in chronic lymphocytic leukaemia.
Age, Specimen part
View SamplesThe goal of this experiment was to determine gene expression changes during influenza A virus infection as the result of expression influenza virus inducible miRNAs in A549 cells.
Small RNA profiling of influenza A virus-infected cells identifies miR-449b as a regulator of histone deacetylase 1 and interferon beta.
Cell line
View SamplesThe ability to generate defined null mutations in mice revolutionized the analysis of gene function in mammals. However, gene-deficient mice generated by using 129-derived embryonic stem (ES) cells may carry large segments of 129 DNA, even when extensively backcrossed to reference strains, such as C57BL/6J, and this may confound interpretation of experiments performed in these mice. Tissue plasminogen activator (tPA), encoded by the PLAT gene, is a fibrinolytic serine protease that is widely expressed in the brain. A large number of neurological abnormalities have been reported in tPA-deficient mice. The studies here compare genes differentially expressed in the brains of Plat-/- mice from two independent Plat-/- mouse derivations to wild-type C57BL/6J mice. One strain denoted “Old” was constructed in ES cells from a 129 mouse and backcrossed extensively to C57BL/6J, and one denoted “New” Plat-/- mouse was constructed using zinc finger nucleases directly in the C57BL/6J-Plat-/- mouse strain. We identify a significant set of genes that are differentially expressed in the brains of Old Plat-/- mice that preferentially cluster in the vicinity of Plat on chromosome 8, apparently linked to more than 20 Mbp of DNA flanking Plat being of 129 origin. No such clustering is seen in the New Plat-/- mice. Overall design: Whole-transcriptome profiling of the cerebral cortex of wild-type control C57BL/6J mice and two independent Plat-/- mice strains on the C57BL/6J background.
Passenger mutations and aberrant gene expression in congenic tissue plasminogen activator-deficient mouse strains.
Age, Specimen part, Cell line, Subject
View SamplesBecause most human stroke victims are elderly, studies of experimental stroke in the aged rather than the young rat model may be optimal for identifying clinically relevant cellular responses, as well for pinpointing beneficial interventions.
Transcriptomics of post-stroke angiogenesis in the aged brain.
Sex, Age, Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Systems biology of the IMIDIA biobank from organ donors and pancreatectomised patients defines a novel transcriptomic signature of islets from individuals with type 2 diabetes.
Age
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