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SRP090980
Mus musculus
78 Downloadable Samples
Illumina HiSeq 2000
Description
The counterregulatory response to hypoglycemia, which restores normal blood glucose levels to ensure sufficient provision of glucose to the brain, is critical for survival. To discover underlying brain regulatory systems, we performed a genetic screen in recombinant inbred mice for quantitative trait loci (QTL) controlling glucagon secretion in response to neuroglucopenia. We identified a QTL on the distal part of chromosome 7 and combined this genetic information with transcriptomic analysis of hypothalami. This revealed Fgf15 as the strongest candidate to control the glucagon response. Fgf15 was found to be expressed by neurons of the dorsomedial hypothalamus and the perifornical area. Intracerebroventricular injection of FGF19, the human ortholog of Fgf15, reduced activation by neuroglucopenia of dorsal vagal complex neurons and of the parasympathetic nerve, leading to a lower glucagon secretion. These data show that Fgf15 in hypothalamic neurons is a regulator of vagal nerve activity in response to neuroglucopenia. Overall design: 36 BXD strains + 4 parental strains, 1 time point, basal condition without treatment
Publication Title
A Genetic Screen Identifies Hypothalamic Fgf15 as a Regulator of Glucagon Secretion.
Sample Metadata Fields
Specimen part, Cell line, Subject
View Samples- Mus musculus
- 24 Downloadable Samples
Affymetrix Mouse Genome 430 2.0 Array (mouse4302)
Description
High-density lipoproteins (HDLs) protect pancreatic cells against apoptosis. This property might be related to the increased risk to develop diabetes in patients with low HDL blood levels. However, the mechanisms by which HDLs protect cells are poorly characterized. Here we use a transcriptomic approach to identify genes differentially modulated by HDLs in cells subjected to apoptotic stimuli.
Publication Title
Involvement of 4E-BP1 in the protection induced by HDLs on pancreatic beta-cells.
Sample Metadata Fields
Specimen part, Cell line
View Samples- Mus musculus
- 6 Downloadable Samples
- Affymetrix Mouse Genome 430 2.0 Array (mouse4302)
Description
Understanding the nature of the various glucose-derived signals for insulin secretion (both triggering and amplifying) is essential for gaining insight into the functional failure of the beta-cells in diabetes and the development of drugs for correcting this problem. The beta-cells uniquely couple changes in cellular metabolism to electrical activity and thus insulin release. In mice, beta-cell specific deletion of the von Hippel-Lindau (VHL) tumor suppressor protein leads to the activation of a HIF transcription program that includes genes involved in glycolysis, suppression of mitochondrial activity and lactate production. This reprogramming of cellular metabolism results in abnormal insulin secretion properties.
Publication Title
PVHL is a regulator of glucose metabolism and insulin secretion in pancreatic beta cells.
Sample Metadata Fields
Sex, Age
View Samples- Rattus norvegicus
- 6 Downloadable Samples
- Affymetrix Rat Gene 1.0 ST Array (ragene10st)
Description
We found that in rodents, b-cell mass expansion during pregnancy and obesity is associated with changes in the expression of a group of islet microRNAs. We were able to reproduce in isolated pancreatic islets the decrease of miR-338-3p level observed in gestation and obesity by activating the G-protein coupled estrogen receptor GPR30 and the GLP1 receptor. Blockade of miR-338-3p in b-cells using specific anti-miR molecules mimicked gene expression changes occurring during b-cell mass expansion and resulted in increased proliferation and improved survival both in vitro and in vivo. These findings point to a major role for miR-338-3p in compensatory b-cell mass expansion occurring under different insulin resistance states.
Publication Title
MicroRNAs contribute to compensatory β cell expansion during pregnancy and obesity.
Sample Metadata Fields
Sex, Specimen part, Cell line
View Samples- Mus musculus
- 12 Downloadable Samples
- Affymetrix Mouse Genome 430 2.0 Array (mouse4302)
Description
We assessed the impact of glucose transporter Glut2 gene inactivation in adult mouse liver (LG2KO mice). This suppressed hepatic glucose uptake but not glucose output. In the fasted state, expression of carbohydrate responsive element-binding protein (ChREBP) and its glycolytic and lipogenic target genes was abnormally elevated. Feeding, energy expenditure, and insulin sensitivity were identical in LG2KO and control mice. Glucose tolerance was normal early after Glut2 inactivation but intolerance developed at later time. This was caused by progressive impairment of glucose-stimulated insulin secretion even though beta-cell mass and insulin content remained normal. Liver transcript profiling revealed a coordinate down-regulation of cholesterol biosynthesis genes in LG2KO mice. This was associated with reduced hepatic cholesterol in fasted mice and a 30 percent reduction in bile acid production. We showed that chronic bile acids or FXR agonist treatment of primary islets increases glucose-stimulated insulin secretion, an effect not seen in islets from fxr-/- mice. Collectively, our data show that glucose sensing by the liver controls beta-cell glucose competence, through a mechanism that likely depends on bile acid production and action on beta-cells.
Publication Title
Hepatic glucose sensing is required to preserve β cell glucose competence.
Sample Metadata Fields
Specimen part
View Samples- Mus musculus
- 12 Downloadable Samples
- Illumina MouseWG-6 v2.0 expression beadchip
Description
Pancreatic beta cells use electrical signals to couple changes in blood glucose concentration to insulin release via extracellular calcium (Ca2+) influx. Sorcin (SRI) is a Ca2+-binding protein whose overexpression in cardiomyocytes rescues the abnormal contractile function of the diabetic heart.
Publication Title
Sorcin Links Pancreatic β-Cell Lipotoxicity to ER Ca2+ Stores.
Sample Metadata Fields
Sex, Age, Specimen part
View Samples- Homo sapiens
- 18 Downloadable Samples
- Illumina HiSeq 2000
Description
The mammalian target of rapamycin complex 1 (mTORC1) is a master regulator of cell growth that is commonly deregulated in human diseases. Here we find that mTORC1 controls a transcriptional program encoding amino acid transporters and metabolic enzymes through a mechanism also used to regulate protein synthesis. Bioinformatic analysis of mTORC1-responsive mRNAs identified a promoter element recognized by activating transcription factor 4 (ATF4), a key effector of the integrated stress response. ATF4 translation is normally induced by phosphorylation of eukaryotic initiation factor 2 alpha (eIF2a) through a mechanism that requires upstream open reading frames (uORFs) in the ATF4 5'' UTR. mTORC1 also controls ATF4 translation through uORFs, but independent of changes in eIF2a phosphorylation. mTORC1 instead employs the 4E-binding protein (4E-BP) family of translation repressors. These results link mTORC1-regulated demand for protein synthesis with an ATF4-regulated transcriptional program that controls the supply of amino acids to the translation machinery. Overall design: RNA-seq analysis of wild-type and ATF4-null HEK293T cells treated with Torin 1 or tunicamycin for 6 h, and ribosome profiling analysis of HEK293T cells treated with Torin 1 for 24 h.
Publication Title
mTORC1 Balances Cellular Amino Acid Supply with Demand for Protein Synthesis through Post-transcriptional Control of ATF4.
Sample Metadata Fields
Subject
View Samples- Mus musculus
- 6 Downloadable Samples
- Affymetrix Mouse Genome 430 2.0 Array (mouse4302)
Description
Peroxisome 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.
Publication Title
PPARβ/δ affects pancreatic β cell mass and insulin secretion in mice.
Sample Metadata Fields
Age, Specimen part
View Samples- Mus musculus
- 12 Downloadable Samples
- Illumina Genome Analyzer II
Description
Ribsome profiling analysis of mRNA translation in mouse cells under conditions of mTOR activiation or inhibition. Overall design: embryonic fibroblasts from 4EBP1/2 p53 mutants treated with Torin1
Publication Title
A unifying model for mTORC1-mediated regulation of mRNA translation.
Sample Metadata Fields
Specimen part, Treatment, Subject
View Samples- Homo sapiens
- 2 Downloadable Samples
- Illumina HumanWG-6 v3.0 expression beadchip
Description
Skeletal muscle of insulin resistant individuals is characterized by lower fasting lipid oxidation and reduced ability to switch between lipid and glucose oxidation. The purpose of the present study was to examine if impaired metabolic switching could be induced by chronic hyperglycemia. Human myotubes were treated with or without chronic hyperglycemia (HG) (20 mmol/l glucose for 4 days), and the metabolism of [14C]oleic acid (OA) and [14C]glucose was studied. Acute glucose (5mmol/l) suppressed OA oxidation by 50% in normoglycemic (NG) (5.5 mmol/l glucose) cells. Myotubes exposed to chronic hyperglycemia showed a significantly reduced OA uptake and oxidation to CO2, whereas acid-soluble metabolites were increased. Glucose suppressibility, the ability of acute glucose to suppress lipid oxidation, was significantly reduced to 21%, while adaptability, the capacity to increase lipid oxidation with increasing fatty acid availability, was unaffected. Glucose uptake and oxidation was significantly reduced by about 40%. Substrate oxidation in presence of mitochondrial uncouplers showed that net and maximal oxidative capacities were significantly reduced after hyperglycemia, and the concentration of ATP was reduced by 25%. However, none of the measured mitochondrial genes were downregulated nor was mitochondrial content. Microarray showed that no genes were significantly regulated by chronic hyperglycemia. Addition of chronic lactate reduced both glucose and OA oxidation to the same extent as hyperglycemia, and this effect was specific for lactate. In conclusions, chronic hyperglycemia reduced substrate oxidation in skeletal muscle cells and impaired the metabolic switching. The effect is most likely due to an induced mitochondrial dysfunction.
Publication Title
Chronic hyperglycemia reduces substrate oxidation and impairs metabolic switching of human myotubes.
Sample Metadata Fields
Specimen part
View Samples