Project description:Enterotoxigenic Escherichia coli (ETEC) strains that produce both heat-stable (ST) and heat-labile (LT) enterotoxins cause severe post-weaning diarrhea in piglets. However, the relative importance of the individual enterotoxins to the pathogenesis of ETEC infection is poorly understood. In this study, we investigated the effect on virulence of an F4+ ETEC strain when removing some or all of its enterotoxins. Several isogenic mutant strains were constructed that lack the expression of LT in combination with one or both types of ST enterotoxins (STa and/or STb). Host early immune responses induced by these mutant strains 4h after infection were compared to the wild type strain GIS26 (O149:F4ac+, LT+ STa+ STb+). At the same time, the immune response of this wild type ETEC strain was compared to the mock-infected control, demonstrating the expression of porcine inflammatory response genes. For these purposes, the small intestinal segment perfusion (SISP) technique and microarray analysis were used and results were validated by qRT-PCR. We also measured net fluid absorption of pig small intestinal mucosa 4h after infection with wild type ETEC, the mutant strains and PBS (mock-infected). These data indicate an important role for STb in inducing small intestinal secretion early after infection. The microarray analysis of the different mutant strains also revealed an important role for STb in ETEC-induced immune response by the significant differential regulation of immune mediators like matrix metalloproteinase 3, interleukin 1 and interleukin 17. We conclude that STb can play a prominent role in ETEC-induced secretion and early immune response.
Project description:Enterotoxigenic Escherichia coli (ETEC) strains that produce both heat-stable (ST) and heat-labile (LT) enterotoxins cause severe post-weaning diarrhea in piglets. However, the relative importance of the individual enterotoxins to the pathogenesis of ETEC infection is poorly understood. In this study, we investigated the effect on virulence of an F4+ ETEC strain when removing some or all of its enterotoxins. Several isogenic mutant strains were constructed that lack the expression of LT in combination with one or both types of ST enterotoxins (STa and/or STb). Host early immune responses induced by these mutant strains 4h after infection were compared to the wild type strain GIS26 Â (O149:F4ac+, Â LT+ Â STa+ Â STb+). At the same time, the immune response of this wild type ETEC strain was compared to the mock-infected control, demonstrating the expression of porcine inflammatory response genes. For these purposes, the small intestinal segment perfusion (SISP) technique and microarray analysis were used and results were validated by qRT-PCR. We also measured net fluid absorption of pig small intestinal mucosa 4h after infection with wild type ETEC, the mutant strains and PBS (mock-infected). These data indicate an important role for STb in inducing small intestinal secretion early after infection. The microarray analysis of the different mutant strains also revealed an important role for STb in ETEC-induced immune response by the significant differential regulation of immune mediators like matrix metalloproteinase 3, interleukin 1 and interleukin 17. We conclude that STb can play a prominent role in ETEC-induced secretion and early immune response. In three pigs, 6 different treatments were performed. These treatments consisted of 4 mutant enterotoxigenic Escherichia coli GIS26 strains, GIS26 wild type strain, or PBS control. Per pig, the small intestine was divided into 6 loops with an interloop in between to avoid cross-contamination. In conclusion, every pig received each of the 6 treatments ad random.
Project description:Weaning is a very critical period for piglets, typically accompanied by lower feed intake, weight loss after weaning and increased mortality. At weaning, piglets are exposed to many stressors, such as loss of mothering, mixing with other litters, end of lactational immunity, and a change in their environment and gut microbiota. After weaning, morphological and histological changes occur in the small intestine of piglets producing a rapid change of feeding regime which is critical for the immature digestive system. Sixteen female piglets were weaned to assess the effect of sorbic acid supplementation on the small intestine tissue transcriptome. At weaning day (T0), 4 piglets were sacrified and tissue samples collected. The remaining 12 piglets were weighted and randomly assigned to different post weaning (T5) diets. Diet A (n=6) contained 5 g/kg of sorbic acid. Diet B (n=6) is the same as Standard diet. Total RNA was isolated from ileum samples to be analyzed using the a CombiMatrix CustomArrayTM 90K platform . Even though diet had no detectable effect during the first 5 days after weaning, outcomes from this study highlighted some of the response mechanisms to the stress of weaning occurring in the piglet gut. A total of 205 differentially expressed genes were used for functional analysis using bioinformatics through BLAST2GO, Ingenuity Pathway Analysis 8.0, and the Dynamic Impact Aproach (DIA). Bioinformatics analysis revealed that Apoptosis, RIG-I-like and NOD-like receptor signaling were altered as a result of weaning. Results suggest that immune and inflammatory responses were activated and likely are a cause of small intestine atrophy as revealed by a decrease in villus height and villus/crypt ratio. Keywords: weaning, gut, gene expression, sorbic acid, microarray analysis
Project description:In this study, we applied the isobaric tags for relative and absolute quantitation (iTRAQ) technique to detect alterations in the proteomic profile of the jejunal mucosa using a porcine model in which piglets were offered the protein-limited (PL) diet. Protein identification and quantification for iTRAQ experiments were performed using ProteinPilot (v4.0.8085) software. The LC-MS/MS data were searched against the UniProtKB (sus scrofa). To minimize the false discovery rate (FDR), a threshold for protein identification was applied, with the confident value > 95% (amount to the confident value “unused ProtScore” > 1.3 in ProteinPilot software), and at least one unique peptide was considered for protein identification. Proteins that were quantified with fold change > 2.0 were considered to be differentially expressed proteins. We identified 5275 proteins, 202 of which were differentially expressed. Furthermore, we adopted function annotation analysis of all identified proteins and function enrichment analysis of all differentially expressed proteins to explore more meaningful proteins and pathways.