Co-expression network analysis using DNA oligonucleotide microarrays of experimentally infected pigs
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ABSTRACT: Co-expression network analysis using DNA oligonucleotide microarrays of experimentally infected pigs. The expression profiles of liver from ten experimentally infected pigs were compared with the profiles of liver from five non-infected contol pigs. The expression profiles of liver from ten experimentally infected pigs were compared with the profiles of liver from five non-infected contol pigs.
Project description:Acute physical exercise elicits changes in gene expression in skeletal muscles to promote metabolic changes and to repair exercise-induced muscle injuries. Here, we investigated the impact of a single bout of running exercise until exhaustion on global transcriptional profiles in porcine skeletal muscles. Using a combined microarray and candidate gene approach, we identified a suite of genes that are differentially expressed in muscles during post-exercise recovery. Thus, several members of the heat shock protein family and proteins associated with proteolytic events were significantly up-regulated, suggesting that protein breakdown, prevention of protein aggregation and stabilization of unfolded proteins are important processes for restoring cellular homeostasis. We also detected an up-regulation of genes, which have been reported to be associated with muscle cell proliferation and differentiation, possibly reflecting an activation, differentiation and fusion of satellite cells to facilitate repair of muscle damage. In addition, exercise increased expression of the nuclear hormone receptors, which regulates metabolic functions associated with lipid, carbohydrate and energy homeostasis. Finally, we observed an unanticipated involvement of long non-coding RNA transcripts, which have been implicated in RNA processing and nuclear retention of adenosine-to-inosine edited mRNAs. These findings expand the complexity of pathways affected by acute contractile activity of skeletal muscle, contributing to a better understanding of the molecular processes that occur in muscle tissue in the recovery phase. Gene expression study of the porcine muscle Biceps femoris in regard to exercise, pigs allowed to rest for 0 hours, 1 hour and 3 hours after exercise were compared with pigs that had not been exercising, using in-house printed porcine two-colour oligonucleotide microarrays.
Project description:Expression profiles of porcine liver and tracheobronchial lung lymph node tissues were studied to identify genes being significantly affected by bacterial infection of the lungs. Samples were taken from liver and tracheobronchial lung lymph node tissues in pigs experimentally infected with A. pleuropneumoniae, serotype 5b, and from healthy non-inoculated control pigs from the same herd. Samples were investigated for changes in gene expression by means of global cDNA microarrays. Expression profiling of samples of liver and lung lymph node tissues from ten pigs challenged with Actinobacillus pleuropneumoniae and from five healthy control pigs was conducted by hybridising all 2x15 samples against a tissue specific common reference consisting of a pool of equal amount of total-RNA from all samples of each tissue type and were balanced with respect to control and challenged animals.
Project description:Boar taint is a major obstacle when using uncastrated male pigs for swine production. One of the main compounds causing this taint is androstenone, a pheromone produced in porcine testis. Here we use microarrays to study the expression of thousands of genes simultaneously in testis of high and low androstenone boars. The study allows identification of genes and pathways associated with elevated androstenone levels. Testicular tissue was collected from 60 boars, 30 with extreme high and 30 with extreme low levels of androstenone, from each of the two breeds Duroc and Norwegian Landrace. The samples were hybridised to porcine arrays containing 26.877 cDNA clones, detecting 563 and 160 genes that were differentially expressed (p < 0.01) in Duroc and Norwegian Landrace, respectively. Of these significantly up- and down-regulated clones, 72 were found to be common for the two breeds, suggesting both general and breed specific mechanisms in regulation of, or response to androstenone levels in boars. Ten of the most significant genes were chosen for verification of expression patterns by quantitative real competitive PCR and real-time PCR. As expected, our results point towards steroid hormone metabolism and biosynthesis as important biological processes for the androstenone levels, but other potential pathways were identified as well. Among these were oxidoreductase activity, ferric iron binding, iron ion binding and electron transport activities. Genes belonging to the cytochrome P450 and hydroxysteroid dehydrogenase families were highly up-regulated, in addition to several genes encoding different families of conjugation enzymes. Furthermore, a number of genes encoding transcription factors were found both up- and down-regulated. The high number of clones belonging to ferric iron and iron ion binding suggests an importance of these genes, and the association between these pathways and androstenone levels is not previously described. This study contributes to the understanding of the complex genetic system controlling and responding to androstenone levels in pig testis. The identification of new pathways and genes involved in the biosynthesis and metabolism of androstenone is an important first step towards finding molecular markers to reduce boar taint. Keywords: high vs low Testicle samples from animals with extreme androstenone values, 30 high and 30 low from each of the two breeds Norwegian Landrace and Duroc, were used for the experiment. Each microarray was hybridised with one high and one low androstenone sample from the same breed, giving a total of 30 arrays for each breed.
Project description:The experiment aimed at studying gene expression differences in longissimus dorsi muscle from pigs from two groups: High versus low intramuscular fat (IMF). The animals were selected from a crossbred population of Landrace x Yorkshire/Landrace x Duroc animals, where we have previously found a highly significant QTL for IMF (Grindflek et al. 2001: "Detection of quantitative trait loci for meat quality in a commercial slaughter pig cross", Mammalian Genome 12(4): 299-304), and by microarray analysis we hoped to identify candidate genes for the QTL and/or pathways that are affected by the genes responsible for the QTL. Keywords: phenotype comparison Direct dye-swap design, with 14 animals in each group (high IMF and low IMF) on 14 separate arrays
Project description:Skatole is one of the compounds causing boar taint in meat of uncastrated male pigs. This study focuses on differences in gene expression of 50 Danish Landrace boars with high and low skatole levels. The animals were divided into 2 groups based on the skatole measurements, with animals having a skatole concentration of less than 0.01 ppm in one group, and above 0.275 ppm in the other group. Gene expression was assessed using porcine oligonucleotide microarrays. We report differential expression of CYP2E1, CYP2A13 and suggests involvement of FMO1, HSD17B13, CBR4 and several transcription factors. Gene expression study of liver, comparison of 25 boars with high and 25 boars with low skatole levels, using in-house printed porcine two-colour oligonucleotide microarrays.
Project description:Actinobacillus pleuropneumoniae is a gram-negative bacterium that causes porcine pleuropneumonia, which is a widespread, highly contagious, and often fatal respiratory disease in swine. In this experiment pigs were inoculated with A. pleuropneumoniae serotype 5b. Liver samples from three non-inoculated pigs and three experimental inoculated pigs were used to characterize the expression profiles of mRNA and microRNA genes using DNA microarrays and Illumina GA deep sequencing, respectively. The microarray analysis identified a large number of genes, which significantly differed in expression in infected versus non-infected animals. MicroRNAs are short single stranded RNA molecules that regulate gene expression by sequence specific binding to the 3M-BM-4 untranslated region (3M-BM-4UTR) of target mRNAs. The deep sequencing analysis determined the identity and abundance of nearly 400 microRNAs, of which a portion was found to significantly differ in expression between the infected and non-infected animals. Target genes for differentially expressed microRNAs were predicted using microCosm Targets, which is based on the miRanda algorithm. Comparison on the two gene lists showed many common genes, which may suggest a causative relationship between changes in microRNA expression and target gene expression. The expression profiles of mRNA and smallRNA in liver from three experimentally infected pigs were compared with the profiles three non-infected contol pigs.
Project description:Acute physical exercise elicits changes in gene expression in skeletal muscles to promote metabolic changes and to repair exercise-induced muscle injuries. Here, we investigated the impact of a single bout of running exercise until exhaustion on global transcriptional profiles in porcine skeletal muscles. Using a combined microarray and candidate gene approach, we identified a suite of genes that are differentially expressed in muscles during post-exercise recovery. Thus, several members of the heat shock protein family and proteins associated with proteolytic events were significantly up-regulated, suggesting that protein breakdown, prevention of protein aggregation and stabilization of unfolded proteins are important processes for restoring cellular homeostasis. We also detected an up-regulation of genes, which have been reported to be associated with muscle cell proliferation and differentiation, possibly reflecting an activation, differentiation and fusion of satellite cells to facilitate repair of muscle damage. In addition, exercise increased expression of the nuclear hormone receptors, which regulates metabolic functions associated with lipid, carbohydrate and energy homeostasis. Finally, we observed an unanticipated involvement of long non-coding RNA transcripts, which have been implicated in RNA processing and nuclear retention of adenosine-to-inosine edited mRNAs. These findings expand the complexity of pathways affected by acute contractile activity of skeletal muscle, contributing to a better understanding of the molecular processes that occur in muscle tissue in the recovery phase. Gene expression study of the porcine muscle Longissimus dorsi in regard to exercise, pigs allowed to rest for 0 hours, 1 hour and 3 hours after exercise were compared with pigs that had not been exercising, using in-house printed porcine two-colour oligonucleotide microarrays.
Project description:The recent development within high-throughput technologies for expression profiling has allowed for parallel analysis of transcriptomes and proteomes in biological systems such as comparative analysis of transcript and protein levels of tissue regulated genes. Until now, such studies of have only included microarray or short length sequence tags for transcript profiling. Furthermore, most comparisons of transcript and protein levels have been based on absolute expression values from within the same tissue and not relative expression values based on tissue ratios. Presented here is a novel study of two porcine tissues based on integrative analysis of data from expression profiling of identical samples using cDNA microarray, 454-sequencing and iTRAQ-based proteomics. Sequence homology identified 2.541 unique transcripts that are detectable by both microarray hybridizations and 454-sequencing of 1.2 million cDNA tags. Both transcript-based technologies showed high reproducibility between sample replicates of the same tissue, but the correlation across these two technologies was modest. Thousands of genes being differentially expressed were identified with microarray. Out of the 306 differentially expressed genes, identified by 454-sequencing, 198 (65 %) were also found by microarray. The relationship between the regulation of transcript and protein levels was analyzed by integrating iTRAQ-based proteomics data. Protein expression ratios were determined for 354 genes, of which 148 could be mapped to both microarray and 454-sequencing data. A comparison of the expression ratios from the three technologies revealed that differences in transcript and protein levels across heart and muscle tissues are positively correlated. We show that the reproducibility within cDNA microarray and 454-sequencing is high, but that the agreement across these two technologies is modest. We demonstrate that the regulation of transcript and protein levels across identical tissue samples is positively correlated when the tissue expression ratios are used for comparison. The results presented are of interest in systems biology research in terms of integration and analysis of high-throughput expression data from mammalian tissues. Keywords: tissue comparison, platform comparison Tissue samples of heart (HEA) and Longissimus dorsi (LDO) were prepared by pooling from five healthy Hampshire gilts at age four to six months and division into six sub-samples, three for each tissue named HEA1, HEA2, HEA3, LDO1, LDO2 and LDO3. The exact same six tissue samples were used for subsequent expression profiling with cDNA microarray, 454-sequencing and iTRAQ-based proteomics. A reference sample for the cDNA microarray experiment and iTRAQ-based proteomics was constructed by combining the six samples. In the microarray experiment, three cDNA microarray slides were used per sample.
Project description:The introduction of long oligonucleotide-based probes has led to many comparative studies of these two platforms in mammals, but remains to be performed for pig. Further, the characteristics of global gene expression in diverse porcine muscle tissues have not been yet been fully established. This is the first global gene expression study of a collection of nine porcine muscle tissues consisting of cardiac and various skeletal muscle types using both cDNA-based and long oligonucleotide-based microarray platforms. The expression profiles from the two platforms agree in differentiating between cardiac, skeletal red, skeletal intermediate and skeletal white muscle types by producing almost identical hierarchical expression clusters. The clusters from both platforms also reveal that gene expression profiles of the skeletal intermediate type are more similar to the red type than to the white type. Analysis of the ability to identify differentially expressed genes based on gene set analysis and GO term integration show a platform overlap of at least 80% for the cardiac-skeletal comparisons and a platform overlap of at least 58% for the skeletal red-white comparisons. Interestingly, the oligonucleotide platform was always able to identify more GO terms associated with differential expression than the cDNA platform. We further examined the skeletal red-white expression differences and found many GO biological processes that are known to be associated with these phenotypes including calcium ion transport, glycolysis, fatty acid beta-oxidation and muscle contraction. In addition, the expression of genes involved in differentiation between slow (red) and fast (white) muscle types such as MYBPC1, TNNI1, TNNT3 and ATP2A1 is highly regulated between red and white type muscles. Not previously shown to be associated with this tissue difference we found the biological process post-Golgi vesicle-mediated transport. Similar results were obtained with GO classes cellular components and molecular functions. Using the gene expression profiles from the oligonucleotide platform we presented and applied an approach for predicting alternatively spliced transcripts across cardiac and skeletal type muscles. One of the predicted transcripts from the gene named UBE2C has been shown to have six transcript variants in human, but they are not expressed in a cardiac-skeletal specific manner as we have observed here. We speculate that one of our oligonucleotide probes for this gene is able to detect only three of these variants whereas the other detects all six variants and that these variants are expressed in a cardiac-skeletal muscle specific manner. These results supports some of the advantages of using oligonucleotide-based microarray platforms for global gene expression profiling and the observed differences in gene expression among muscle tissues contribute to the understanding of the molecular processes behind porcine muscle biology. Keywords: tissue comparison, platform comparison Muscle tissue samples from heart (HEA), Vastus intermedius (VIN), Infraspinatus (ISP), Supraspinatus (SSP), Biceps femoris (BFE), Longissimus dorsi (LDO), Semimembranosus (SME), Semitendinosus (STE) and Triceps brachii (TBR). A common reference sample was constructed by combining all samples. The exact same tissue samples were used for expression profiling with cDNA microarrays and 70-mer long oligonucleotide microarrays.
Project description:The objective of this study was to identify porcine genes which expression was affected by experimental infection with A. pleuropneumoniae within 24 hours after experimental challenge. Microarray experiments were conducted to reveal genes being significantly differentially expressed in infected versus non-infected lung tissue and in liver and lung lymph node tissue from three challenged versus two non-challenged animals. Keywords: Host response Three comparisons were done: - infected versus non-infected lung tissue sampled from three challenged pigs - liver tissue from three challenged versus two non-challenged animals - lung lymph node tissue from three challenged versus two non-challenged animals All experiments were conducted as common reference design.