Unknown,Transcriptomics,Genomics,Proteomics

Dataset Information

Role of SPI-1 Secreted Effectors, SipA, SopABDE2, in Acute Bovine Response to Salmonella enterica Serovar Typhimurium

ABSTRACT: Salmonella enterica Serovar Typhimurium (S. Typhimurium) causes enterocolitis in humans and calves characterized by diarrhea and polymorphonuclear cell (PMN) influx to the intestinal mucosa. The Salmonella Type III Secretion System encoded at Pathogenicity Island I (SPI-1) translocates the Salmonella effector proteins SipA, SopA, SopB, SopD, and SopE2 into the host epithelial cell cytoplasm. These five effector proteins act in concert to induce fluid secretion and transcription of C-X-C chemokines, which serve to recruit PMNs to the intestine. While the individual molecular interactions of these Salmonella proteins with cultured host cells have been extensively characterized, their combined role in the generation of fluid secretion and inflammation is less well understood. A bovine ligated ileal loop model was used in conjunction with a custom bovine microarray to determine intestinal response to acute S. Typhimurium infection in the calf. Gene expression responses to both wild type S. Typhimurium a delta sipA, sopABDE2 mutant were measured at seven times during the initial 12 hours of infection. Microarray analysis confirmed increased expression of genes encoding proteins previously associated with immune response to Salmonella spp. infection. Gene expression changes were mapped to molecular interaction pathways and changes in expression of mechanistic genes, which are defined as perturbed genes identified by Bayesian genetic network modeling, were strongly involved in the mechanisms of the host immune response. In addition to correctly identifying known effects of wild type S. Typhimurium on host (bovine) gene expression, Bayesian genetic network modeling identified novel effects of S. Typhimurium on several molecular interaction pathways. Novel effects impacted gene regulation in the following pathways: adipocytokine signaling, insulin signaling, complement and coagulation cascades, axon guidance, gap junction, neuroactive ligand-receptor interaction, long-term depression, long-term potentiation, melanogenesis, and natural killer cell mediated cytotoxicity. Known effects were observed in the following pathways: regulation of actin cytoskeleton, apoptosis, cytokine-cytokine receptor interaction, cell adhesion molecules (CAMs), MAPK signaling, calcium signaling, Jak-STAT signaling, leukocyte transendothelial migration, adherens junction, tight junction, and ECM-receptor interactions, phosphatidylinositol signaling system, and antigen processing and presentation. Quantitative real-time PCR was used to verify the expression of some of these mechanistic genes. Microarrays were used to examine the transcriptional profiles of bovine intestinal epithelia infected with wild type Salmonella enterica serotype Typhimurium (control and wild type or delta sipA sopABDE2 mutant infected) across seven time points (15 min, 30 min, 1, 2, 4, 8, and 12 hours). Experiments were performed in quadruplicate (bovine ligated ileal loops surgeries were performed with four calves), generateing a total of 84 arrays.

ORGANISM(S): Bos taurus

SUBMITTER: Leslie Adams

PROVIDER: E-GEOD-13847 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Publications

Role of SPI-1 secreted effectors in acute bovine response to Salmonella enterica Serovar Typhimurium: a systems biology analysis approach.

Lawhon Sara D SD Khare Sangeeta S Rossetti Carlos A CA Everts Robin E RE Galindo Cristi L CL Luciano Sarah A SA Figueiredo Josely F JF Nunes Jairo E S JE Gull Tamara T Davidson George S GS Drake Kenneth L KL Garner Harold R HR Lewin Harris A HA Bäumler Andreas J AJ Adams Leslie Garry LG

PloS one 20111111 11

Salmonella enterica Serovar Typhimurium (S. Typhimurium) causes enterocolitis with diarrhea and polymorphonuclear cell (PMN) influx into the intestinal mucosa in humans and calves. The Salmonella Type III Secretion System (T3SS) encoded at Pathogenicity Island I translocates Salmonella effector proteins SipA, SopA, SopB, SopD, and SopE2 into epithelial cells and is required for induction of diarrhea. These effector proteins act together to induce intestinal fluid secretion and transcription of C ...[more]

PMID: 22096503

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Project description:Mycobacterium avium subspecies paratuberculosis (MAP) infection is established following the ingestion of bacteria, their penetration of the intestinal mucosa and subsequent events of the host-parasite interaction. These bacteria invade M cells, macrophages and are capable of resisting host defenses and multiply to reach very high numbers intracellular. Mycobactrium avium subsp. avium (MAA) is an antigenically and genetically similar organisms but is relatively nonpathogenic for cattle. MAA organisms appear to infect cattle, but unlike cattle infected with MAP, cattle infected with MAA typically mount an effective systemic immune response, form caseous granuloma, and eliminate the infection. This study was designed to understand the similarities and differences in the host responses during MAP and MAA infection. Neonatal calves were infected (ligated ileal loops) with PBS, MAP, or avirulent MAA following which samples were collected at 30 min, 1h, 2h, 4h, 8h, or 12h. Post-infection, RNA was collected, processed, and then hybridized to custom bovine gene expression arrays, each of which represented 13,258 transcripts spotted in duplicate. Arrays were normalized by scaling against the average reference intensity value (i.e., average across all arrays), normalized by global mean, and then log transformed before statistical analyses were performed. Pairwise comparisons of averaged signal values and StudentM-bM-^@M-^Ys t test were performed using GeneSifter software (VizX Labs, Seattle, WA). A fold-change of at least 1.5-fold and a p value of 0.05 or less was required for a difference in signal to be considered statistically significant. When comparing the transcriptional responses of calves infected with the MAA versus MAP, unique patterns of expression were clearly visible. In general, numbers of transcripts altered in response to infection were much greater for MAA-infected animals than for those infected with the MAP. No genes were significantly up-regulated in MAP-infected animals at the earliest time point tested (30 min), and only modest numbers of genes were increased in expression over the experimental time course. On the other hand, up-regulated transcripts were detected by 30 min in MAA-infected animals and peaked by 2 hr. Differences in the numbers of down-regulated genes between MAP-infected and MAA-infected animals (compared to PBS-infected controls) were less pronounced. At the earliest time points, MAP-infected calves had a greater number of down-regulated genes than did animals infected with MAA. This trend was reversed at 8 and 12 hr post-infection. Keywords: Gene expression profiling by microarray Microarrays were used to examine the transcriptional profiles of bovine intestinal mucosa inoculated with PBS, MAP or MAA and across six time points (30 min, 1, 2, 4, 8, and 12 hours). Experiments were performed in quadruplicate for PBS, MAP, and MAA (bovine ligated ileal loops surgeries were performed with four calves). For one surgery, MAA was used for 4 time ponts only, thus generateing a total of 70 arrays.

Project description:Gut dysbiosis and host genetics are implicated as causative factors in inflammatory bowel disease, yet mechanistic insights are lacking. Longitudinal analysis of ulcerative colitis patients following total colectomy with ileal anal anastomosis (IPAA) where >50% develop pouchitis, offers a unique setting to examine cause vs. effect. To recapitulate human IPAA, we employed a mouse model of surgically-created blind self-filling (SFL) and self-emptying (SEL) ileal loops. SFL exhibit fecal stasis due to directional peristalsis motility oriented towards away from the loop end, whereas SEL remain empty. In wild type mice, SFL, but not SEL, develop pouch-like microbial communities without accompanying active inflammation. However, in genetically susceptible IL-10-/- deficient mice, SFL, but not SEL, exhibit severe inflammation and mucosal transcriptomes resembling human pouchitis. Germ-free IL10-/- mice conventionalized with wild type SFL, but not SEL, microbiota, develop severe colitis. These data demonstrate an essential role for fecal stasis, gut dysbiosis, and genetic susceptibility and offer insights into human pouchitis and ulcerative colitis. All animal protocols were approved by IACUC at the University of Chicago. All animals were C57Bl/6 mice that were bred and housed under standard 12:12 light/dark conditions at the University of Chicago. Female mice aged 6-8 weeks were fed ad libitum gel diet 76A (Cat# 72-07-5022, Clear H20, Portland, ME) for 5-days prior to surgery to prevent obstruction at the anastomosis. Animals were anesthetized with ketamine/xylazine. Aseptic surgery was performed to resect 2.5cm of ileum 3cm proximal to the ileal-cecal value with anastomosis to the ileum using 8-0 suture (Figure 1a). The abdominal wall was closed with interrupted 4-0 silk suture and skin was closed with staples. Analgesics (betanorphine mg/kg BW) were provided post-operatively. After 5 weeks, mice were humanely euthanized. Intestinal loops were collected for RNA, protein, and histology. Loop, sham ileum, and sham colon contents were collected and snap frozen at −80°C for microbiota analysis. Human biopsies and stool samples were obtained under IRB approval and privacy protocols were followed. Our initial work demonstrated up regulation of TLR4 signaling in the mucosa of self-filling ileal loops. We hypothesized that TLR4 may be in-part responsible for mediating the metaplasia and inflammatory responses observed. Therefore, TLR4 KO mice were used to test this hypothesis and subsequently demonstrated attenuated responses in these parameters.

Dataset Information

Role of SPI-1 Secreted Effectors, SipA, SopABDE2, in Acute Bovine Response to Salmonella enterica Serovar Typhimurium

Publications

Role of SPI-1 secreted effectors in acute bovine response to Salmonella enterica Serovar Typhimurium: a systems biology analysis approach.

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