Expansion of beta cells from the limited number of adult human islet donors is an attractive prospect for increasing cell availability for cell therapy of diabetes. However, while evidence supports the replicative capacity of adult beta cells in vivo, attempts at expanding human islet cells in tissue culture resulted in loss of beta-cell phenotype. Using a genetic lineage-tracing approach we have provided evidence for massive proliferation of beta-cell-derived (BCD) cells within these cultures. Expansion involves dedifferentiation resembling epithelial-mesenchymal transition (EMT). Epigenetic analyses indicate that key beta-cell genes maintain a partially open chromatin structure in expanded BCD cells, although they are not transcribed. Here we report that BCD cells can be induced to redifferentiate by a combination of soluble factors. The redifferentiated cells express beta-cell genes, store insulin in typical secretory vesicles, and release it in response to glucose. The redifferentiation process involves mesenchymal-epithelial transition, as judged from changes in gene expression. Moreover, inhibition of the EMT effector SLUG using shRNA results in stimulation of redifferentiation. BCD cells also give rise at a low rate to cells expressing other islet hormones, suggesting transition through an islet progenitor-like stage during redifferentiation. These findings suggest that ex-vivo expansion of adult human islet cells is a promising approach for generation of insulin-producing cells for transplantation, as well as basic research, toxicology studies, and drug screening.
Insulin-producing cells generated from dedifferentiated human pancreatic beta cells expanded in vitro.
Specimen part
View SamplesCytokines have been shown to play a key role in the destruction of beta cells. In the rat insulinoma cell line (INS-1ab) overexpressing pancreatic duodenum homeobox 1 (Pdx1) increases sensitivity to Interleukin 1b (IL-1b). To elucidate mechanisms of action underlying Pdx1 driven potentiation of beta-cell sensitivity to IL-1, we performed a microarray analysis of INS-1ab cells with and without Pdx1 overexpression exposed to IL-1 between 2h and 24h.
Divalent metal transporter 1 regulates iron-mediated ROS and pancreatic β cell fate in response to cytokines.
Cell line, Time
View SamplesIdentify shear and side-specific miRNAs in Human Aortic Valvular Endothelial Cells using the following conditions: 1) fHAVEC exposed to OS (FO), 2) vHAVEC exposed to OS (VO), 3) fHAVEC exposed to LS (FL), and 4) vHAVEC exposed to LS (VL).
Discovery of shear- and side-specific mRNAs and miRNAs in human aortic valvular endothelial cells.
Specimen part
View SamplesThe accumulation of unfolded or misfolded proteins in the endoplasmic reticulum (ER) results in the condition called ER stress which induces the unfolded protein response (UPR) which is a complex cellular process that includes changes in expression of many genes. Failure to restore homeostasis in the ER is associated with human diseases. To identify the underlying changes in gene expression in response to ER stress, we induced ER stress in human B-cells and then measured gene expression at 10 time-points. We followed up those results by studying cells from 60 unrelated people. We rediscovered genes that were known to play a role in ER stress response and uncovered several thousand genes that are not known to be involved. Two of these are VLDLR and INHBE which showed significant increase in expression following ER stress in B-cells and
Gene expression and genetic variation in response to endoplasmic reticulum stress in human cells.
Cell line, Subject, Time
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Histone methyltransferase DOT1L coordinates AR and MYC stability in prostate cancer.
Specimen part, Cell line, Treatment
View SamplesWe performed expression profiling of prostate cancer cells, LNCaP and PC3 cells that were treated with the specific DOT1L inhibitor EPZ004777 (1uM) for 8 days. We found that unique genes were differentially expressed in both cell lines.
Histone methyltransferase DOT1L coordinates AR and MYC stability in prostate cancer.
Specimen part, Cell line, Treatment
View SamplesGene expression profiles generated from skeletal muscle biopsies taken from participants of the HERITAGE family study. Participants completed an endurance training regime in which a skeletal muscle biopsy was taken prior to the start and after the final session of the program. Biopsies were used to generate Affymetrix gene expression microarrays.
The Role of Eif6 in Skeletal Muscle Homeostasis Revealed by Endurance Training Co-expression Networks.
No sample metadata fields
View SamplesThis SuperSeries is composed of the SubSeries listed below.
The B-cell receptor controls fitness of MYC-driven lymphoma cells via GSK3β inhibition.
No sample metadata fields
View SamplesSimilar to resting mature B cells, where the B-cell antigen receptor (BCR) is essential for cellular survival, surface BCR expression is conserved in most mature B cell lymphomas. The identification of activating BCR mutations and the growth disadvantage upon BCR knockdown of cells of certain lymphoma entities has led to the view that BCR signaling is required for tumour cell survival. Consequently, the BCR signaling machinery has become a new target in the therapy of B cell malignancies. Here, we studied the effects of BCR ablation on MYC-driven mouse B cell lymphomas and compared them to observations in human Burkitt lymphoma. Whereas BCR ablation did not, per se, significantly affect lymphoma growth, BCR-negative (BCR-) tumour cells rapidly disappeared in the presence of their BCR-expressing (BCR+) counterparts in vitro and in vivo. This required neither cellular contact, nor factors released by BCR+ tumour cells. Instead, BCR loss induced the rewiring of central carbon metabolism increasing the sensitivity of receptor-less lymphoma cells to nutrient restriction. The BCR attenuated GSK3 activity to support MYC-controlled gene expression. BCR- tumour cells exhibited increased GSK3 activity and were rescued from their competitive growth disadvantage by GSK3. BCR-negative lymphoma variants that restored competitive fitness, normalized GSK3 following constitutive activation of the MAPK pathway, commonly through Ras mutations. Similarly, in Burkitt lymphoma, activating RAS mutations may propagate Ig-crippled tumour cells, which usually represent a minority of the tumour bulk. Thus, while BCR expression enhances lymphoma cell fitness, BCR-targeted therapies may profit from combinations with drugs targeting BCR-less tumour cells.
The B-cell receptor controls fitness of MYC-driven lymphoma cells via GSK3β inhibition.
No sample metadata fields
View SamplesRNA seqeuncing was performed to identifiy changes in genes expression and alternative splicing following SRSF3 depletion in pluripotent stem cells. Overall design: Induced pluripotent stem cells (iPSCs) generated from reprogrammable conditional SRSF3 knockout (SRSF3-KO/OKSM) mouse embryonic fibroblasts (MEFs) were induced for 24h to deplete SRSF3 and RNA seqeuncing was performed.
SRSF3 promotes pluripotency through <i>Nanog</i> mRNA export and coordination of the pluripotency gene expression program.
Specimen part, Subject
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