Project description:Although immune mechanisms have been described for Peyer’s patch function, in discriminating food nutrients and commensal microflora from pathogenic challenge, an understanding of gene expression patterns associated with normal intestinal homeostasis is lacking. The effects of commensal bacterial colonization on global gene expression in the small intestine of germ-free mice have been described (1, 2). However, no studies have compared expression patterns of various healthy lymphoid tissues in conventionally-raised pigs or other species. The objective of this study was to investigate the pattern of normal gene expression in jejunal Peyer’s patches (JPP) of healthy pigs. We hypothesized that gene expression of intact jejunal Peyer's patch is characterized by genes associated with absorption and secretory functions as well as genes associated with GALT-specific immune functions. Eight hybridizations were performed, with dye swaps of JPP mRNA from four juvenile pigs. Each hybridization compared JPP from an individual pig to the jejunal mesenteric lymph node reference sample, which was pooled from all juvenile pigs in the study. However, two of the hybridizations resulted in poor quality data, and were excluded from further analysis. Normalization, hierarchical clustering, data visualization, and statistical analysis were performed by GeneSpring version 6.2 (Silicon Genetics, Redwood, CA). GeneSpring standardized the intensities for each spot by subtracting the local background, and then normalized globally by locally weighted linear regression (Lowess). A Lowess curve was fit to the log-intensity versus log-ratio plot. 20.0% of the data was used to calculate the Lowess fit at each point. This curve was used to adjust the control value for each measurement. If the control channel was lower than 10 then 10 was used instead. Spots with a flag value of “0” were excluded. The intensity of negative control DNA-containing spots was used to additionally exclude low intensity data. Negative controls include the gene for Arabidopsis thaliana homeodomain-like protein (AY054571); 200 ng/microl Poly(dA) (Amersham, Piscataway, NJ); a 461 bp fragment of the kanamycin-resistant gene, amplified from the pET24b+ plasmid (Novagen, Madison, WI); PRRS virus strain VR-2332 (PRU87392) ORFs 2, 3, 4, 5, 6 and 7; pCMVSport 6 plasmid (Invitrogen, Carlsbad, CA); and pGEM-T plasmid (Promega, Madison WI). The mean intensity of the negative controls for both Cy3 and Cy5 was calculated for each slide, and spots with a mean intensity less than the mean intensity + 2SD were excluded from further analysis. After normalization, GeneSpring averaged replicate spots for each clone across hybridizations. GeneSpring used the Cross Gene Error Model, which was based on replicate values. A Student’s t-test with the Benjamini and Hochberg false discovery rate multiple testing correction (MTC) verified the difference between the natural log of the normalized gene expression ratio (JPP:j-MLN) and a ratio of 1.0. p-values less than 0.05 were considered significant. Series_references: 1.Fukushima K, Ogawa H, Takahashi K, Naito H, Funayama Y, Kitayama T, Yonezawa H, and Sasaki I. Non-pathogenic bacteria modulate colonic epithelial gene expression in germ-free mice. Scand J Gastroenterol 38: 626-634, 2003. 2. Hooper LV, Wong MH, Thelin A, Hansson L, Falk PG, and Gordon JI. Molecular analysis of commensal host-microbial relationships in the intestine. Science 291: 881-884, 2001.

Project description:The objective of the current study was to evaluate the effects of postruminal casein infusion and exogenous glucagon-like peptide 2 (GLP-2) administration on transcriptomic pathways and functions of the jejunal mucosa in cattle using next-generation RNA sequencing. Twenty-four Holstein steers [250 ± 23 kg body weight (BW)] received a continuous abomasal infusion of 3.94 g raw corn starch/kg of BW combined with either 0 or 1.30 g casein/kg of BW for 7 d. Steers received subcutaneous injections in two equal portions daily of excipient (0.5% bovine serum albumin) or 100 µg GLP-2/kg of BW per day. At the end of the 7-d treatment period, steers were slaughtered for collection of the jejunal mucosa. Total RNA was extracted from jejunal mucosal tissue, strand-specific cDNA libraries were prepared, and RNA sequencing was conducted to generate 150-bp paired-end reads at a depth of 20 M reads in each direction. Differentially expressed genes (DEG), KEGG pathway enrichment, and gene ontology enrichment between treatments were determined based on the FDR-corrected P-value. Postruminal casein infusion downregulated (padj < 0.05) 7 genes of the jejunal mucosa and did not result in any enriched KEGG pathways or gene ontologies. Exogenous GLP-2 administration upregulated (padj < 0.05) 667 DEGs, 26 KEGG pathways, 198 biological processes, 56 cellular components, and 60 molecular functions. Exogenous GLP-2 downregulated (padj < 0.05) 1101 DEGs, 14 KEGG pathways, 270 biological processes, 105 cellular components, and 46 molecular functions. Enrichment analyses revealed that exogenous GLP-2 administration affected several pathways involving mucosal growth, nutrient digestion, absorption, and metabolism, and intestinal barrier function. Results of the current study identified pathways affected by exogenous GLP-2 administration that could have implications for improved animal growth and feed efficiency in cattle. This research generated novel targets for future research to elucidate mechanisms of GLP-2-mediated responses in the jejunal mucosa.

Project description:Although immune mechanisms have been described for Peyer’s patch function, in discriminating food nutrients and commensal microflora from pathogenic challenge, an understanding of gene expression patterns associated with normal intestinal homeostasis is lacking. The effects of commensal bacterial colonization on global gene expression in the small intestine of germ-free mice have been described (1, 2). However, no studies have compared expression patterns of various healthy lymphoid tissues in conventionally-raised pigs or other species. The objective of this study was to investigate the pattern of normal gene expression in jejunal Peyer’s patches (JPP) of healthy pigs. We hypothesized that gene expression of intact jejunal Peyer's patch is characterized by genes associated with absorption and secretory functions as well as genes associated with GALT-specific immune functions. Eight hybridizations were performed, with dye swaps of JPP mRNA from four juvenile pigs. Each hybridization compared JPP from an individual pig to the jejunal mesenteric lymph node reference sample, which was pooled from all juvenile pigs in the study. However, two of the hybridizations resulted in poor quality data, and were excluded from further analysis. Normalization, hierarchical clustering, data visualization, and statistical analysis were performed by GeneSpring version 6.2 (Silicon Genetics, Redwood, CA). GeneSpring standardized the intensities for each spot by subtracting the local background, and then normalized globally by locally weighted linear regression (Lowess). A Lowess curve was fit to the log-intensity versus log-ratio plot. 20.0% of the data was used to calculate the Lowess fit at each point. This curve was used to adjust the control value for each measurement. If the control channel was lower than 10 then 10 was used instead. Spots with a flag value of “0” were excluded. The intensity of negative control DNA-containing spots was used to additionally exclude low intensity data. Negative controls include the gene for Arabidopsis thaliana homeodomain-like protein (AY054571); 200 ng/microl Poly(dA) (Amersham, Piscataway, NJ); a 461 bp fragment of the kanamycin-resistant gene, amplified from the pET24b+ plasmid (Novagen, Madison, WI); PRRS virus strain VR-2332 (PRU87392) ORFs 2, 3, 4, 5, 6 and 7; pCMVSport 6 plasmid (Invitrogen, Carlsbad, CA); and pGEM-T plasmid (Promega, Madison WI). The mean intensity of the negative controls for both Cy3 and Cy5 was calculated for each slide, and spots with a mean intensity less than the mean intensity + 2SD were excluded from further analysis. After normalization, GeneSpring averaged replicate spots for each clone across hybridizations. GeneSpring used the Cross Gene Error Model, which was based on replicate values. A Student’s t-test with the Benjamini and Hochberg false discovery rate multiple testing correction (MTC) verified the difference between the natural log of the normalized gene expression ratio (JPP:j-MLN) and a ratio of 1.0. p-values less than 0.05 were considered significant. Series_references: 1.Fukushima K, Ogawa H, Takahashi K, Naito H, Funayama Y, Kitayama T, Yonezawa H, and Sasaki I. Non-pathogenic bacteria modulate colonic epithelial gene expression in germ-free mice. Scand J Gastroenterol 38: 626-634, 2003. 2. Hooper LV, Wong MH, Thelin A, Hansson L, Falk PG, and Gordon JI. Molecular analysis of commensal host-microbial relationships in the intestine. Science 291: 881-884, 2001. Keywords: other

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Gene expression profiles of the mouse jejunal epithelial cells with breakfast skipping feeding pattern

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