Location: Animal Parasitic Diseases Laboratory2011 Annual Report
1a. Objectives (from AD-416)
The specific objectives of this agreement includes Identify differentially expressed (DE) genes in blood in response to PRRSV infection. Determine putative gene sets and pathways that predict a pig's ability to clear PRRSV infection and maintain weight gain; and Validate utility of gene sets and pathways for prediction of responsiveness to PRRSV infections in multiple populations. Predictive blood tests of pigs with improved PRRS disease resistance and growth maintenance; increased understanding of mechanisms involved in pig responses to PRRSV infection; scientific publications.
1b. Approach (from AD-416)
Michigan State University (MSU) researchers will contribute to the first two objective through developing statistical methods for selecting samples for evaluation from Tempus tube preserved blood samples collected through the PRRS Host Genetics Consortium (PHGC) representing pigs in different virus/weight categories. Perform all the microarray work and transcriptional profiling for the first two objectives and analyze all microarray data (processing and normalization and use of statistical programs to identify DE genes). MSU researchers will also collaborate on planning analysis of DE gene QPCR data (generated by USDA ARS BARC) for all Objectives.
3. Progress Report
This Agreement reports results of functional genomic analyses to determine response pathways that differ in porcine respiratory and the reproductive syndrome (PRRS) resistant versus susceptible pigs. ARS Researchers at Beltsville, MD have partnered with Michigan State University (MSU) scientists to use PRRS Host Genetics Consortium (PHGC) samples to assess whole blood gene expression responses during 42 days infection. To date 72 microarrays have been completed with blood RNA samples from 12 pigs collected at 0, 4, 7, 11, 14, 28, 42 days post infection to identify genes and pathways that are associated with pigs that clear PRRS virus (PRRSV) and that grow well despite PRRSV infection. Biostatistical and bioinformatic analyses are now underway at MSU to determine which genes are correlated with viral load and/or weight gain comparing the most desirable, PRRS resistant low virus/high weight gain pigs with the worst, PRRS susceptible high virus/ low weight gain pigs, and the PRRS tolerant, high virus/high weight gain pigs. As a result of these studies we expect to develop predictive gene and protein expression pathways to help identify pigs which resist PRRSV infection and grow normally. (NP103 2c) This project was monitored through regular email and phone contact, scheduled conference calls, and a yearly Consortium meeting with the participating labs discussing project plans, experimental design, and reviewing data and presentation options.