Unknown,Transcriptomics,Genomics,Proteomics

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Analysis of Genes in the Hypothalamus Controlling Feed Intake and Energy Metabolism in Neonatal Chicks

ABSTRACT: 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.

ORGANISM(S): Gallus gallus

SUBMITTER: Tom Porter

PROVIDER: E-GEOD-13257 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Publications

Transcriptional and pathway analysis in the hypothalamus of newly hatched chicks during fasting and delayed feeding.

Higgins Stacy E SE Ellestad Laura E LE Trakooljul Nares N McCarthy Fiona F Saliba Jason J Cogburn Larry A LA Porter Tom E TE

BMC genomics 20100309

<h4>Background</h4>The hypothalamus plays a central role in regulating appetite and metabolism. However, the gene networks within the hypothalamus that regulate feed intake and metabolism, and the effects of fasting on those pathways are not completely understood in any species. The present experiment evaluated global hypothalamic gene expression in newly hatched chicks using microarray analysis to elucidate genes and pathways regulated by feeding, fasting, and delayed feeding. Ten groups of chi ...[more]

PMID: 20214824

Similar Datasets

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:This study integrates global transcriptional profiling and the metabolic perturbation induced by fasting and re-feeding. Genetic control of growth and development should be revealed by systematic modeling of metabolic and regulatory pathways. Chicken oligo arrays were used for transcriptional profiling in two time-course experiments. Two critical developmental stages were chosen: immediately after hatchling (Wk1) and prior to marketing of broiler chickens (Wk6). Only male chickens were used to simplify the experimental design. A RNA reference design was employed for microarray hybridization using two reference RNA pools derived from all individuals sampled at either Wk1 or Wk6. Microarray data was acquired using GenePix Pro software. Loess normalization and a linear mixed model were applied in data processing using the R statistical package with LIMMA software [Smyth, G. K. (2004) Linear models and empirical Bayes methods for assessing differential expression in microarray experiments. Statistical Applications in Genetics and Molecular Biology, Vol. 3, No. 1, Article 3]. The results show hundreds of differentially expressed genes, which are regulated by age and the metabolic perturbation of fasting and re-feeding. Numerous common genes were found at both developmental stages (Wk1 and Wk6) that could be candidates for controlling growth and development of chickens. Differential expression revealed by either microarray or qRT-PCR analyses of selected genes was highly consistent. QRT-PCR verification of genes acutely depressed by fasting includes AGO1, ANGTPL3, ATPCL, FASN, FAT, ME1, PPARG, SCD1, SREBP1 and THRSPA. Genes up-regulated by fasting were ALDOB, IL-15, LDHB, LIPIN2, PANK1, PPARA and UPP2. These genes are functionally assigned to metabolic enzymes, transcription factors, acute phase proteins, immune factors and involved in various pathways (i.e., fatty acid and amino acid metabolism, glycolysis, growth factor signaling and immune defense). A reference RNA design was used for microarray hybridizations, where the same reference RNA pool was co-hybridized to each target sample on an microarray. The reference RNA pool was made from an equal amount of high-quality amplified RNA (aRNA), derived from all liver samples within each experiment (Wk1 = 50 samples and Wk6 = 30 samples). The reference RNA pool was labeled with Alexa 647 while each target sample was labeled with Alexa 555.

Project description:The effects of fasting have been studied extensively, predominantly on isolated processes, within a specific organ. No comprehensive study of the adaptations was available for different organs, let alone interrelating them, which left the understanding of the body’s orchestration of fasting response limited. The gene expression profiles of brain, small intestine, kidney, liver and skeletal muscle were therefore studied in mice subjected to short, moderate and prolonged fasting. Functional category enrichment, network, and text-mining analyses were employed to scrutinize the overall adaptive response, aiming to identify responsive pathways, processes and networks, and their regulation. The implicated processes did not follow the accepted carbohydrate-lipid-protein succession of energy substrates expenditure. Instead, they were activated simultaneously in different organs during the whole duration of fasting. The most prominent changes occurred in lipid and steroid metabolism, especially in the liver and kidney, which showed biochemically similar, orchestrated responses. They were accompanied by suppression of the immune response and cell turnover, particularly in the small intestine, tied in with increased proteolysis in the muscle. Enhanced defence against oxidative damage, obvious in all the organs, was the top reaction of the brain, otherwise shown to be extremely well protected from starvation. The major transcription regulators of fasting response in different organs were FoxO transcription factors, AP-1, p53, cMyc, Sp1, EGF and HNF4α. The revealed interorgan interactions between metabolic, inflammatory and cell turnover responses are essential when designing strategies to treat the starvation affected individuals, while stressing the significance of using complimentary bioinformatics tools in the high-throughput data analysis. 6 week-old male FVB mice were fasted for 0, 12, 24, 48 or 72 hours before sacrifice (N = 5 per group). From each mouse total RNA was isolated from five organs - liver, small intestine, kidney, brain, and calf muscle. Five microarrays per experimental condition (five tissues, five timepoints) were performed. We used a common reference design. The single common-reference sample was a pool of equal amounts of RNA from all the samples investigated, including additional samples from 5 mice that were fasted for 48 hours and supplemented with vitamin B complex after 24 and 36 hours of fasting.

Dataset Information

Analysis of Genes in the Hypothalamus Controlling Feed Intake and Energy Metabolism in Neonatal Chicks

Publications

Transcriptional and pathway analysis in the hypothalamus of newly hatched chicks during fasting and delayed feeding.

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