Metabolomics,Unknown,Transcriptomics,Genomics,Proteomics

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Hepatic Transcriptional Profiling of Hatchling Chicks and Market-age Broiler Chickens during Fasting and Re-feeding

ABSTRACT: 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.

ORGANISM(S): Gallus gallus

SUBMITTER: Larry Cogburn

PROVIDER: E-GEOD-9745 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Project description:MicroRNA (miRNA) is a family of small regulatory RNA that post-transcriptionally regulates many biological functions including growth and development. Chicken miR-143 and miR-10a are expressed in both the embryonic and post-hatch chick in a spatio-temporal manner. In order to study the functions of these miRNAs, loss of function and microarray approaches were employed. Spleen cells were isolated from embryonic day 18 chickens and immediately transfected with either a synthetic miR-143 inhibitor or a synthetic miR-10a inhibitor or a negative control oligo-nucleotide (Dharmacon). Cultures were maintained for 48 hrs and microarray analysis was performed using the Arizona Gallus gallus 20.7K long oligoarray (GPL6049). Differentially expressed genes were identified for each miRNA by comparing the miRNA knock-down group to the negative control group. The differentially expressed genes were functionally categorized using the DAVID Functional Annotation Tool (http://david.abcc.ncifcrf.gov/). The 3â-UTR of the up-regulated genes (de-repressed after the miRNAs knock-down) were scanned for potential miR-143 or miR-10a binding sites using the miRanda algorithm version 3.1 (http://www.microrna.org/microrna). In addition, the Chicken (Gallus gallus) Unigene database (NCBI) was also used to predict potential targets of these miRNAs. A set of predicted targets for both miRNAs was selected and validated by dual luciferase reporter gene assay. Overall, many of the identified targets for miR-143 are associated with cell proliferation, tumerigenesis and apoptosis. Many of potential targets for miR-10a are associated with immune response. A reference designed microarray was performed in which samples (Cy3) were co-hybridized with the reference RNA pool (Cy5) on the array. The microarray data set was processed using within- and across-array loess normalization method in JMP Genomics 3.0, SAS (Cary, NC). Data quality was evaluated using the MA plots process and the correlation and grouped scatter plots procedure (JMP Genomics 3.0). Differentially expressed genes were identified using ANOVA process on JMP Genomics 3.0 with fixed effect of treatments and random effect of arrays.

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:Background In broilers, heat stress can result in reduced feed consumption, digestive inefficiency, impaired metabolism, and even death. The broiler sector of the U.S. poultry industry incurs approximately $52 million in heat stress-related losses annually. The objective of this study is to characterize the effects of chronic, cyclic heat stress on the transcriptome of a metabolically active organ, the liver. Characterizing the liver transcriptome of heat-stressed broilers will help clarify the effects of heat stress on metabolism. This information will provide a platform for future investigations that further elucidate physiologic responses to heat stress and seek methods to ameliorate the negative impacts of heat. Results Transcriptome sequencing of the livers of 8 broiler males using Illumina HiSeq 2000 technology, resulted in a total of 138 million, 100 base pair single end reads, yielding 13.8 gigabases of sequence. Forty genes were differentially expressed at a significance level of P-value < 0.05 and a fold change ≥ 2 in response to chronic, cyclic heat stress (mid-point of the last day of a 7-day cyclic heat stress of 7 hours per day), with 27 down-regulated and 13 up-regulated. Two gene networks were created from the function-based Ingenuity Pathway Analysis (IPA) of the differentially expressed genes; “Cell Signaling, Molecular Transport, Small Molecule Biochemistry” and “Endocrine System Development and Function, Small Molecule Biochemistry Cell Signaling”. Members of the MAPK signaling pathway and differentially expressed genes that are associated with MAPK-related functions were prominent in the networks. Cellular proliferation and differentiation, inflammationand stress-related signaling, and apoptosis-associated genes were down-regulated in response to heat stress. Genes responsible for inhibiting feed intake and sphingolipidrelated signaling were up-regulated. Genes involved with the regulation of inflammation, stress, thyroid hormone level, and body temperature were both up- and down-regulated. Conclusions Chronic, cyclic heat stress of broilers results in metabolic changes that can be characterized through RNA-seq analysis of the liver transcriptome. The primary affected pathways included cell signaling, molecular transport, endocrine system development and signaling, and small molecule biochemistry. Examination of 2 heat treatments. Four heat stressed liver samples and 4 control liver samples analyzed.

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Hepatic Transcriptional Profiling of Hatchling Chicks and Market-age Broiler Chickens during Fasting and Re-feeding

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