1a. Objectives (from AD-416)
1. Profile the in vivo whole blood RNA and cytokine response to Salmonella Typhimurium infection in animals with high and low fecal shedding phenotypes. 2. Using the same animals in Aim 1, profile the in vitro whole blood RNA and cytokine response to lipopolysaccaride or Salmonella Typhimurium treatments prior to in vivo exposure to Salmonella Typhimurium of the pigs. 3. Annotate response profiles for common expression patterns and functional themes and develop regulatory network information on response to inflammatory stimuli. 4. Develop and test predictive models for identifying pigs with decreased fecal shedding post-infection.
1b. Approach (from AD-416)
The assembled team has expertise and recent experience in collecting and analyzing porcine transcriptional profiling data, as well as in developing computational regulatory networks. We will propose to integrate and extend these datasets to specifically build a database containing transcriptional and regulatory factor-chromatin binding data of the inflammatory response to pathogen challenge. We will use the most comprehensive approaches possible, including the Affymetrix Porcine GeneChip' and/or pig long oligo arrays for RNA work, and chromatin immunoprecipitation methods for selected transcription factors to develop regulatory network data. These data will then be analyzed using several computational approaches to find genes and develop an understanding of regulatory networks responsible for differences in outcome after infection, and this new information will be applied to find predictors for not only which swine are more resistant to Salmonella infection and shedding but also optimal health traits. We believe this approach will be successful in both establishing molecular measures of health and disease, predicting Salmonella resistant versus susceptible pigs, and identifying the most promising targets for improving animal health and growth in challenging environments.
3. Progress Report
In collaboration with investigators at Iowa State University, we have transcriptionally profiled the response of pigs that shed low levels of Salmonella compared to highly persistent Salmonella shedding pigs. Following inoculation of the pigs, Salmonella shedding status was monitored over a three week period to identify low shedding and highly persistent shedding pigs. The purpose of analyzing the gene expression of these diverse shedding populations is to find differences in the pig’s response to Salmonella that associate with the susceptibility of pigs to Salmonella colonization, shedding and carrier status. Our goal of the project is to identify traits that could be exploited to enhance the resistance of swine herds to Salmonella colonization through immunomodulation, aid in the selection of breeder herds that have elevated resistance to Salmonella, and/or support the development of microbial diagnostic tools to identify Salmonella-carrier pigs. Progress is monitored by regular e-mails, phone calls, and site visits.