Murine pancreatic beta cell line MIN6 was growth at two different concentrations of glucose (22,2 and 5,5 mM of glucose), 37C, 5% CO2 and was treated at four different concentrations of human amylin (0, 1, 10 and 20 uM) during three different times (2, 12 and 24 hours)
Impairment of the ubiquitin-proteasome pathway is a downstream endoplasmic reticulum stress response induced by extracellular human islet amyloid polypeptide and contributes to pancreatic beta-cell apoptosis.
No sample metadata fields
View SamplesIntra-islet crosstalk between islet cells is critical in orchestrating the body’s response to changes in blood glucose levels, but is incompletely understood. In this study, we used transgenic mouse lines that allowed the purification and transcriptomic characterisation of alpha, beta, and delta cells, yielding an RNA-sequencing database that can be searched for regulatory proteins which are differentially expressed between cell types. As an illustrative example, we examined the expression of g-protein coupled receptors, and found that the ghrelin receptor, Ghsr, was highly expressed in delta cells compared to alpha and beta cells. GHSR excitation elicited increases in cytosolic calcium levels in primary delta cells. In the perfused pancreas, the application of ghrelin stimulated somatostatin secretion, correlating with a decrease in insulin and glucagon release, which was sensitive to somatostatin receptor antagonism. These results show that ghrelin acts specifically on delta cells within pancreatic islets to affect blood glucose regulation. Overall design: Examination of transcriptomic profiles obtained from pancreatic alpha, beta and delta cells
Transcriptomic profiling of pancreatic alpha, beta and delta cell populations identifies delta cells as a principal target for ghrelin in mouse islets.
Specimen part, Cell line, Subject
View SamplesEnteroendocrine L-cells release hormones that control metabolism and appetite and are targets under investigation for the treatment of diabetes and obesity. Understanding L-cell diversity and expression profiles is critical for identifying target receptors that will translate into altered hormone secretion. We performed single cell RNA sequencing of mouse L-cells from the upper small intestine to distinguish cellular populations, revealing that L-cells form 3 major clusters: a group with typical characteristics of classical L-cells, including high expression of Gcg and Pyy; a cell type overlapping with Gip-expressing K-cells; and a unique cluster expressing Tph1 and Pzp that was predominantly located in duodenal villi and co-produced 5HT. Expression of G-protein coupled receptors differed between clusters, suggesting the cell types are differentially regulated, and would be differentially targetable. Our findings support the emerging concept that many enteroendocrine cell populations are highly overlapping, with individual cells producing a range of peptides previously assigned to distinct cell types. Overall design: Single cell RNA sequencing of mouse duodenal L-cells cells
Single-cell RNA-sequencing reveals a distinct population of proglucagon-expressing cells specific to the mouse upper small intestine.
Specimen part, Subject
View SamplesZinc finger nucleases (ZFN) are powerful tools for editing genes in cells. Here we use ZFNs to interrogate the biological function of human ADPGK, which encodes an ADP-dependent glucokinase (ADPGK), in tumour cell lines. The hypothesis tested is that ADPGK utilises ADP to phosphorylate glucose under conditions where ATP becomes limiting, such as hypoxia. We characterised two ZFN knockout clones in each of two tumour cell lines (H460 and HCT116). All four lines had frameshift mutations in all alleles at the target site in exon 1 of ADPGK, and were ADPGK-null by immunoblotting. ADPGK knockout had little or no effect on cell proliferation, but compromised the ability of H460 cells to survive siRNA silencing of hexokinase-2 under oxic conditions, with clonogenic survival falling from 213% for the parental line to 6.40.8% (p=0.002) and 4.30.8% (p=0.001) for the two knockouts. A similar increased sensitivity to clonogenic cell killing was observed under anoxia. No such changes were found when ADPGK was knocked out in HCT116 cells, for which the parental line was less sensitive than H460 to anoxia and to hexokinase-2 silencing. While knockout of ADPGK in HCT116 cells caused few changes in global gene expression, knockout of ADPGK in H460 cells caused notable up-regulation of mRNAs encoding cell adhesion proteins. Surprisingly, we could discern no effect on glycolysis as measured by glucose consumption or lactate formation under oxic or anoxic conditions, or extracellular acidification rate (Seahorse XF analyser) under oxic conditions in a variety of media. However, oxygen consumption rates were generally lower in the ADPGK knockouts, in some cases markedly so. Collectively, the results demonstrate that ADPGK can contribute to tumour cell survival under conditions of high glycolytic dependence, but the phenotype resulting from knockout of ADPGK is cell line dependent and appears to be unrelated to priming of glycolysis.
Expression and role in glycolysis of human ADP-dependent glucokinase.
Cell line
View SamplesPeroxisome proliferator-activated receptor beta/delta protects against obesity by reducing dyslipidemia and insulin resistance via effects in various organs, including muscle, adipose tissue, liver, and heart. However, nothing is known about the function of PPAR-beta in pancreas, a prime organ in the control of glucose metabolism. To gain insight into so far hypothetical functions of this PPAR isotype in insulin production, we specifically ablated Ppar-beta in pancreas. The mutated mice developed a chronic hyperinsulinemia, due to an increase in both beta-cell mass and insulin secretion. Gene expression profiling indicated a broad repressive function of PPAR-beta impacting the vesicular compartment, actin cytoskeleton, and metabolism of glucose and fatty acids. Analyses of insulin release from the islets revealed an increased second-phase glucose-stimulated insulin secretion. Higher levels of PKD, PKC-delta and diacyglycerol in mutated animals lead to an enhanced formation of trans-Golgi network (TGN)-to-plasma-membrane transport carriers in concert with F-actin disassembly, which resulted in increased insulin secretion and its associated systemic effects. Taken together, these results provide evidence for PPAR-beta playing a repressive role on beta-cell growth and insulin exocytosis, which shed new light on its anti-obesity action.
PPARβ/δ affects pancreatic β cell mass and insulin secretion in mice.
Age, Specimen part
View SamplesTo examine the impact of tumors on the immune system, we compared global gene expression profiles of peripheral blood T cells from previously untreated patients with B cell chronic lymphocytic leukemia (CLL) with those from age-matched healthy donors. Although the cells analyzed were not part of the malignant clone, analysis revealed differentially expressed genes, mainly involved in cell differentiation in CD4 cells and defects in cytoskeleton formation, vesicle trafficking, and cytotoxicity in CD8 cells of the CLL patients. In coculture experiments using CLL cells and T cells from healthy allogeneic donors, similar defects developed in both CD4 and CD8 cells. These changes were induced only with direct contact and were not cytokine mediated. Identification of the specific pathways perturbed in the T cells of cancer-bearing patients will allow us to assess steps to repair these defects, which will likely be required to enhance antitumor immunity.
Chronic lymphocytic leukemia cells induce changes in gene expression of CD4 and CD8 T cells.
No sample metadata fields
View SamplesImmune deficiency is common in cancer, but the biological basis for this and ways to reverse it remains elusive. Here we present a mouse model of B cell chronic lymphocytic leukemia (CLL) that recapitulates changes in the non-malignant circulating T cells seen in patients with this illness.1 To validate this model, we examined changes in T cell gene expression, protein expression and function in Em-TCL1 transgenic mice as they developed CLL 2,3 and demonstrate that development of CLL in these transgenic mice is associated with changes in impaired T cell function and in gene expression in CD4 and CD8 T cells similar to those observed in patients with this disease. Infusion of CLL cells into non-leukemia bearing Em-TCL1 mice rapidly induces these changes, demonstrating a causal relationship between leukemia and the induction of T cell changes. This model allows dissection of the molecular changes induced in CD4 and CD8 T cells by interaction with leukemia cells and further supports the concept that cancer results in complex abnormalities in the immune microenvironment.
E(mu)-TCL1 mice represent a model for immunotherapeutic reversal of chronic lymphocytic leukemia-induced T-cell dysfunction.
No sample metadata fields
View SamplesWork previously published by our group has demonstrated that T cells from patients with chronic lymphocytic leukaemia (CLL) show differentially regulated genes compared with healthy T cells. This study was initiated to examine if these gene expression changes were unique to CLL T cells or common to an alternative leukaemia, acute myeloid leukaemia (AML).
Peripheral blood T cells in acute myeloid leukemia (AML) patients at diagnosis have abnormal phenotype and genotype and form defective immune synapses with AML blasts.
Sex, Age
View SamplesIt has been shown that tumor infiltrating immune cells have a profound impact on the outcome of FL. To find mechanisms whereby TILs are altered gene expession analysis of highly pure TILs were performed.
Follicular lymphoma cells induce changes in T-cell gene expression and function: potential impact on survival and risk of transformation.
Specimen part, Subject
View SamplesAberrant promoter DNA hypermethylation is a hallmark of cancer; however, whether this is sufficient to drive cellular transformation in the absence of genetic mutations is not clear. To investigate this question, we use a CRISPR/dCas9 based epigenetic editing tool, where an inactive form of Cas9 is fused to DNMT3A and its regulator DNMT3L. Using this system, we show simultaneous de novo DNA methylation of genes commonly methylated in cancer, CDKN2A, RASSF1, HIC1 and PTEN in primary myoepithelial cells isolated from healthy human breast tissue. We find that promoter methylation is maintained in this system, even in the absence of the fusion construct and results in sustained repression of CDKN2A and RASSF1 transcripts which prevents cells from entering senescence. The phenotype is associated with retuned expression of a subset of genes to levels in early passage cells; however, the outgrowing myoepithelial cells are not immortal but proliferate for 18-20 population doublings before cell cycle arrest. Finally, we show that the key driver of this phenotype is repression of CDKN2A transcript p16, but prolonged proliferation is enhanced by combined hypermethylation and repression of both CDKN2A transcripts p16 and p14. This work demonstrates that hit-and-run epigenetic events can prevent senescence entry, a potential first step in the disease process. Overall design: RNA-seq experiment with n=3 biological replicates of primary myoepithelial transfection with 26x gRNAs targeting DNA methylation as described.
Hit-and-run epigenetic editing prevents senescence entry in primary breast cells from healthy donors.
Specimen part, Subject
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