Genome-wide analysis of fasting induced gene expression in the mouse hypothalamus
Ontology highlight
ABSTRACT: This study utilized AgRP+/- and AgRP-/- mice either under fed or 30h fasted conditions, to reveal genes that are regulated by fasting and AgRP.
Project description:Analysis of fasting-induced change of metabolites in mice confirmed that glucose level was reduced in the liver, but unaffected in the brain of fasted mice. To explore molecular mechanisms for the preferential glucose supply to the brain upon fasting, we compared gene expression profiles of the brain between fasted and fed mice. Gene ontology (GO) term analysis revealed the enrichment of one GO term, “active membrane transporters activity”. We also showed that fasting enhances the expression of a glucose transporter Slc2a1 (Glut1) gene.
Project description:The molecular control of feeding after fasting is essential for maintaining energy homeostasis, and overfeeding usually leads to obesity. RNA interference has been clinically successful in managing diseases, and the identification of a feeding-regulated microRNA (miRNA), which remains a challenge, could be a strategy for combating obesity. By performing a comprehensive genome-wide microRNA screening in the arcuate nucleus of the hypothalamus (ARC) of fasted mice and ad libitum mice, we found a significant increase in miR-7a-5p levels after fasting. miR-7a-5p was highly expressed in the ARC, and inhibition of miR-7a-5p specifically in AgRP neurons reduced food intake and body weight gain. miR-7a-5p inhibited S6K1 gene expression by binding to its 3’-UTR. Furthermore, the reduction of food intake by anti-miR-7a-5p was partially reversed by the downregulated mechanistic target of rapamycin complex 1 (mTOR1)/ribosomal S6 kinase 1 (S6K1) signaling in the AgRP neurons. Importantly, intracerebroventricular administration of the miR-7a-5p inhibitor could reduce food intake and body weight. Collectively, our findings suggest miR-7a-5p as an orexigenic factor in AgRP neurons and a potential novel target for obesity treatment.
Project description:The goal of these studies was to determine the effects of fasting on skeletal muscle mRNA levels in healthy human subjects. Seven healthy adult human subjects fasted for 40 hours and then a muscle biopsy (fasting sample) was obtained from the vastus lateralis muscle. Immediately after the first muscle biospy, subjects then ate a mixed meal. Six hours after the first muscle biopsy, a second muscle biopsy (fed sample) was obtained from the contralateral vastus lateralis muscle. In each subject, mRNA levels under fasting conditions were normalized to mRNA levels under fed conditions, which were set at 1.
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
Project description:The functional balance between brown adipose tissue (BAT) and white adipose tissue (WAT) is important for metabolic homeostasis. We compared the effects of fasting on the gene expression profiles in BAT, WAT and liver, using DNA microarray analysis. Tissues were obtained from rats that had been fed or fasted for 24 h. Taking the false discovery rate (FDR) into account, we extracted the top 1,000 genes that were expressed differentially between fed and fasted rats. In all three tissues, Gene Ontology analysis revealed marked changes in the expression of âmetabolismâ category genes and a hypergeometric test demonstrated that within this category, lipid and protein biosynthesis-related genes were down-regulated. These findings indicate simultaneous down-regulation of genes involved in energy-consuming pathways in the BAT, WAT and liver of fasted rats. In the BAT of fasted rats, there was marked up-regulation of genes in the âprotein ubiquitinationâ category, suggesting that the ubiquitin-proteasome system is involved in saving energy as an adaptation to food shortage. Experiment Overall Design: Rats (7-week-old) were given a commercial diet between 10:00 and 16:00 for 7 days. At 10:00 on day 8, they were divided into two groups that comprised animals of similar body weights. One group continued to be fed as described above (fed group, n=4 for array analysis), whereas the other group were not fed (fasted group, n=4 for array analysis). Both groups received water ad libitum. At 16:00 on day 8, the liver, interscapular BAT and perinephrial WAT were excised, and analyzed for fasting effect.
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 Ten experimental groups with 4 replicates each were analyzed. A reference RNA design was used for this microarray. Equal amounts of amplified RNA (aRNA) from all samples were pooled and labeled with the Alexa 647 to create the reference pool. Each individual sample was labeled with Alexa 555. Each slide was hybridized with both the reference pool and one sample.
Project description:Four weeks old male broilers, fed ad libitum or fasted for 16h or 48h were used to describe the evolution of global gene expression profiles in chicken liver during a 48h fasting period using a chicken 20K oligo array. Among the 20460 oligos on the microarray, 13057 were identified as aligning with a unique coding region of the 2.1 Washington University assembly of the chicken sequence genome. So the statistical analyses were performed on this 13057 gene set. A total number of 2062 differentially expressed genes were identified. The number of genes differentially expressed after 48h of fasting compared to the Fed state was 4-fold higher than after 16h of fasting. Analysis was focused on 1162 genes selected among these 2062 genes for which a human ortholog could be identified, thus allowing functional information collect. Quantitative real-time polymerase chain reaction (qRT-PCR) validated our results. Keywords: Chicken fasted, transcriptional profiling, differentially expressed genes
Project description:Transcriptional profiling coupled with blood metabolite analyses were used to identify porcine genes and pathways that respond to a fasting treatment or to a D298N missense mutation in the melanocortin-4 receptor (MC4R) gene. Gilts (12 homozygous for D298 and 12 homozygous for N298) were either fed ad libitum or fasted for 3 days. Fasting decreased body weight and backfat and increased serum concentrations of non-esterified fatty acid and urea. In response to fasting, 7,029 genes in fat and 1,831 genes in liver were differentially expressed (DE, q value less than 0.05). MC4R genotype did not affect gene expression, body weight, backfat depth, and any measured serum metabolite concentration. Pathway analyses of fasting-induced DE genes indicated that both liver and fat down-regulated energetically costly processes such as lipid and steroid synthesis and up-regulated efficient energy utilization pathways. Fasting increased expression of genes in involved in glucose sparing pathways in liver and extracellular matrix pathways in adipose tissue. Within the DE genes, transcription factors (TF) that regulate many DE genes were identified, confirming the involvement of TF that are known to regulate fasting response and implicating additional TF that are not known to be involved in energy homeostatic responses. Interestingly, estrogen receptor 1 transcriptionally controls fasting induced genes in fat that are involved in cell matrix morphogenesis. Our findings indicate a transcriptional response to fasting in two key metabolic tissues of pigs that was corroborated by changes in blood metabolites; and involvement of novel putative transcriptional regulators in the immediate adaptive response to fasting. Experiment Overall Design: Gilts (n=24; 12 wildtype and 12 homozygous for D298N) were either fed ad libitum or fasted for 3 days in a completely randomized complete block design with a 2x2 factorial treatment structure.
Project description:Temporally restricted feeding has a profound effect on the circadian clock. Fasting and feeding paradigms are known to influence hepatic transcription. This dataset shows the dynamic effects of refeeding mice after a 24hour fasting period. Mice were entrained for two weeks under ad libitum access to food. Mice were then released into constant darkness and food was withdrawn at CT4 on the first day in constant darkness. On the second day in constant darkness mice were either fed (Refed) or continously fasted (Fast) at CT4. Liver tissue was collected at the indicated timepoints. Total RNA was extracted and standard Affymetrix protocol were used for amplification, labeling and hybridization
Project description:The effect of liver specific deletion of the insulin receptor substrate-1 (Irs1) and/or Irs2 upon gene expression in the fasted and fed liver of mice; and the effect of liver specific Foxo1 deletion in the Irs1 and Irs2 knockout liver during fasting and feeding.