Genome-wide mRNA expression profiles of FACS-purified rat beta cells freshly isolated from control and 24h-fasted rats
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ABSTRACT:
ORGANISM(S): Rattus norvegicus
PROVIDER: GSE30964 | GEO | 2011/09/01
SECONDARY ACCESSION(S): PRJNA146225
REPOSITORIES: GEO
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Project description:The study was designed to capture the in vivo adaptations of nutrient-sensing pancreatic beta cells to fed or fasted (24h) state. Short periods of fasting are thought to mediate the beta cells’ competence for insulin synthesis and secretion. We examined whether it influenced their typical mRNA expression. After 24h of fasting, a 1.5 fold change was detected in 1.5% of all assayed transcripts (p<0.05), with 95% of altered genes (430 of 452) being down-regulated (Fig.6A). Suppression was more marked for a panel of genes with beta cell-specific expression, of which 12% were 1.5-fold suppressed. Suppressed beta cell marker genes were statistically enriched in gene clusters of endoplasmic reticulum (ER), ER to Golgi transport, protein folding and secretory vesicle-mediated transport, i.e. the pathways of protein synthesis and transport. (See Martens G.A. et al. PLoS One 2011) For both experimental conditions, 3 biological replicates were studied, each representing an independent isolation from n= 5, 10w-old male Wistar rats. Beta cells were snap frozen in liquid nitrogen immediately after the end of the isolation procedure, i.e. within 3 hours after animal killing.
2011-08-31 | E-GEOD-30964 | biostudies-arrayexpress
Project description:In cell models, changes in the “accessible” pool of plasma membrane (PM) cholesterol are linked with the regulation of ER sterol synthesis and metabolism by the Aster family of nonvesicular transporters. However, the relevance of such nonvesicular transport mechanisms for lipid homeostasis in vivo has not been defined. Here we reveal two physiological contexts that generate accessible PM cholesterol and engage the Aster pathway in liver: fasting and reverse cholesterol transport (RCT). During fasting, adipose tissue–derived fatty acids activate hepatocyte sphingomyelinase to liberate sequestered PM cholesterol. Aster-dependent cholesterol transport during fasting facilitates cholesteryl ester (CE) formation, cholesterol movement into bile, and VLDL production. During RCT, HDL delivers excess cholesterol to the hepatocyte PM through SR-BI. Loss of hepatic Asters impairs cholesterol movement into feces, raises plasma cholesterol levels, and causes cholesterol accumulation in peripheral tissues. These results reveal fundamental mechanisms by which Aster cholesterol flux contributes to hepatic and systemic lipid homeostasis.
2022-10-24 | GSE206278 | GEO
Project description:Background The gut is a major energy consumer, but a comprehensive overview of the adaptive response to fasting is lacking. Gene-expression profiling, pathway analysis, and immunohistochemistry were therefore carried out on mouse small intestine after 0, 12, 24, and 72 hours of fasting. Results Intestinal weight declined to 50% of control, but this loss of tissue mass was distributed proportionally among the gut’s structural components, so that the microarrays’ tissue base remained unaffected. Unsupervised hierarchical clustering of the microarrays revealed that the successive time points separated into distinct branches. Pathway analysis depicted a pronounced, but transient early response that peaked at 12 hours, and a late response that became progressively more pronounced with continued fasting. Early changes in gene expression were compatible with a cellular deficiency in glutamine and metabolic adaptations directed at glutamine conservation, inhibition of pyruvate oxidation, stimulation of glutamate catabolism via aspartate and phosphoenolpyruvate to lactate, and enhanced fatty-acid oxidation and ketone-body synthesis. In addition, the expression of key genes involved in cell cycling and apoptosis was suppressed. At 24 hours of fasting, many of the early adaptive changes abated. Major changes upon continued fasting implied the production of glucose rather than lactate from carbohydrate backbones, a downregulation of fatty-acid oxidation and a very strong downregulation of the electron-transport chain. Cell cycling and apoptosis remained suppressed. Conclusion The changes in gene expression indicate that the small intestine rapidly looses mass during fasting to generate lactate or glucose and ketone bodies. Meanwhile, intestinal architecture is maintained by downregulation of cell turnover. Keywords: fasting response, time course
2007-11-12 | GSE8019 | GEO
Project description:Human estrogen-responsive breast cancer cell line MCF-7 wt were used to produce stable clones expressing ER-beta tagged with TAP-tag respectively at the C-term and at the N-term (Ct-ER-beta and Nt-ER-beta) as previously described. MCF7 wt and beta clone cells were cultured in steroid-free medium for 5 days and then were treated with 10nM of 17-beta-estradiol, or vehicle (ETOH). RNA was extracted after 2h, 4h and 8h of stimulation with 17-ß-estradiol 10 nM (+E2) or ethanol vehicle . Total RNA extracted by Ct-ER-beta and Nt-ER-beta cells were pooled (TAP-ER-beta). For mRNA expression profiling, 500 ng total RNA were reverse transcribed and used for synthesis of cDNA and biotinylated cRNA. Finally cRNA were hybridized for 18 hours on Illumina HumanHT-12 v3.0 BeadChips and after scanning, data analysis was performed.
2011-07-29 | E-TABM-1051 | biostudies-arrayexpress
Project description:MCF-7 TET Off cells (MCF-7 wt) were used to produce stable clones expressing ER-beta tagged with TAP-tag respectively at the C-term and at the N-term (C-TAP-ER-beta and N-TAP-ER-beta) or expressing ER-alpha tagged (C-TAP-ER-alpha). All were grown in Dulbecco's modified Eagle's medium (DMEM). Then cells were lysed and RNA extracted were pooled. For mRNA expression profiling, 500 ng total RNA were reverse transcribed and used for synthesis of cDNA and biotinylated cRNA. Finally cRNA were hybridized for 18 hours on Illumina HumanHT-12 v3.0 BeadChips and after scanning, data analysis was performed.
2011-10-11 | E-TABM-1052 | biostudies-arrayexpress
Project description:Obesity-associated metabolic complications are generally considered to emerge from abnormalities in carbohydrate and lipid metabolism, whereas the status of protein metabolism is not well studied. Here, we performed comparative polysome and associated transcriptional profiling analyses to study the dynamics and functional implications of endoplasmic reticulum (ER)-associated protein synthesis in the mouse liver under conditions of obesity and nutrient deprivation. lean wild type and genetically obese (ob/ob) mice with or without overnight fasting were sacrificed with their liver tissues removed. ER-associated polysomes were purified and analyzed by microarray.
2012-09-01 | E-GEOD-39375 | biostudies-arrayexpress
Project description:Dietary restriction regimens lead to enhanced stress resistance and extended lifespan in many species through the regulation of fasting and/or diet responsive mechanisms. The fasting stimulus is perceived by sensory neurons and causes behavioral and metabolic adaptations. Several studies have implicated that the nervous system is involved in the regulation of longevity. However, it remains largely unknown whether the nervous system contributes to the regulation of lifespan and/or stress resistance elicited by fasting. In this study, we first investigated the role of the nervous system in fasting-elicited longevity and stress resistance. We found that lifespan extension in Caenorhabditis elegans caused by an intermittent fasting (IF) regimen was suppressed by functional defects in sensory neurons. The IF-induced longevity was also suppressed in a mutant that lacks the enzyme required for the synthesis of an amine neurotransmitter, octopamine (OA), which acts in the absence of food, i.e., under fasting conditions. Although OA administration did not significantly extend the lifespan, it enhanced organismal resistance to oxidative stress. This enhanced resistance was suppressed by a mutation of the OA receptors, SER-3 and SER-6. Moreover, we found that OA administration promoted the nuclear translocation of DAF-16, the key transcription factor in fasting responses, and that the OA-induced enhancement of stress resistance required DAF-16. Altogether, our results suggest that OA signaling, which is triggered by the absence of food, shifts the organismal state to a more protective one to prepare for environmental stresses. To investigate the involvement of DAF-16 and octopamine receptors (SER-3 and SER-6) in octopamine-induced genome-wide transcriptome alterations, we conducted transcriptome analysis.
2017-03-08 | GSE89731 | GEO
Project description:Lipid transfer proteins of the Ups1/PRELID1 family facilitate the transport of phospholipids across the intermembrane space of mitochondria in a lipid-specific manner. Heterodimeric complexes of yeast Ups1/Mdm35 or human PRELID1/TRIAP1 shuttle phosphatidic acid (PA) synthesized in the endoplasmic reticulum (ER) to the inner membrane, where it is converted to cardiolipin (CL), the signature phospholipid of mitochondria. Loss of Ups1/PRELID1 proteins impairs the accumulation of CL and broadly affects mitochondrial structure and function. Unexpectedly and unlike yeast cells lacking the cardiolipin synthase Crd1, Ups1 deficient yeast cells exhibit glycolytic growth defects, pointing to functions of Ups1-mediated PA transfer beyond CL synthesis. Here, we show that the disturbed intramitochondrial transport of PA in ups1D cells leads to altered phospholipid composition of the ER membrane, independent of disturbances in CL synthesis. The impaired flux of PA into mitochondria is associated with the increased synthesis of phosphatidylcholine (PC) and a reduced phosphatidylethanolamine (PE)/PC ratio in the ER of ups1D cells which suppresses the unfolded protein response (UPR). Moreover, we observed inhibition of TORC1 signaling in these cells. Activation of either UPR by ER protein stress or of TORC1 signaling by disruption of its negative regulator, the SEACIT complex, increased cytosolic protein synthesis and restored glycolytic growth of ups1D cells. These results demonstrate that PA influx into mitochondria is required to preserve ER membrane homeostasis and that its disturbance is associated with impaired glycolytic growth and cellular stress signaling.
2021-01-21 | GSE160861 | GEO
Project description:During human fasting, metabolic markers, including butyrates, carnitines, and branched-chain amino acids, are upregulated for energy substitution through gluconeogenesis and use of stored lipids. We performed non-targeted, accurate semiquantitative metabolomic analysis of human whole blood, plasma, and red blood cells during 34-58 hr fasting of four volunteers. During this period, 44 of ~130 metabolites increased 1.5~60-fold. Consistently fourteen were previously reported. However, we identified another 30 elevated metabolites, implicating hitherto unrecognized metabolic mechanisms induced by fasting. Metabolites in pentose phosphate pathway are abundant, probably due to demand for antioxidants, NADPH, gluconeogenesis and anabolic metabolism. Global increases of TCA cycle-related compounds reflect enhanced mitochondrial activity in tissues during fasting. Enhanced purine/pyrimidine metabolites support RNA/protein synthesis and transcriptional reprogramming, which is promoted also by some fasting-related metabolites, possibly via epigenetic modulations. Thus diverse, pronounced metabolite increases result from greatly activated catabolism and anabolism stimulated by fasting. Anti-oxidation may be a principal response to fasting.
2019-09-11 | MTBLS549 | MetaboLights
Project description:Delayed access to feed following hatching has been associated with reduction in growth performance in chicks. However, the gene networks within the hypothalamus that regulate feed intake and metabolism, and the effects of fasting on those pathways are not well understood. The present experiment evaluated global hypothalamic gene expression in neonatal chicks using the Arizona Gallus gallus 20.7K Oligo Array v1.0 to elucidate genes and pathways regulated by feeding, fasting, and refeeding. Ten groups of chicks were sampled over four days post-hatch, including: control (at hatch), 24h fed, 24h fasted, 48h fed, 48h fasted, 48h fasted then 4h refed, 72h fed, 48h fasted then 24h refed, 96h fed, and 48h fasted then 48h refed. Non-esterified fatty acids were elevated, and triglycerides were decreased in fasted chicks at 24 and 48h, indicating that fasting induced physiological changes. Hypothalamic samples were collected from 16 chicks per group, and total RNA was extracted and pooled for hybridization (n=4). Expression patterns of selected genes were confirmed by quantitative real-time PCR. Two-fold differences in gene expression were detected in 1,272 genes between treatment groups, and of those, 119 genes were significantly (P<0.05) different. Assignment of gene ontology terms to the significant genes resulted in 34 different categories of biological processes, with 24% of genes participating in signal transduction, transport, or metabolic processes. Genes that were upregulated during fasting (and confirmed by qPCR) include FK506BP51, which is involved in the formation of steroid receptor complexes, and deiodinase type II, which is responsible for converting the thyroid hormone T4 into T3. Confirmed genes, downregulated due to fasting, included proopiomelanocortin and fatty acid binding protein 7. Other regulated genes were identified that play a role in feeding and obesity in other species, such as relaxin 3 and adrenergic receptor-β2. Further analysis of differentially regulated genes could provide new information regarding the role of the hypothalamus in feed intake and metabolism. Keywords: Metabolic perturbation
2008-10-18 | GSE13257 | GEO