2010 Annual Report
1a.Objectives (from AD-416)
The specific objectives for this agreement are to 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)
The University will check for differential gene expression of targeted genes e.g., CD163, SIGLEC1, PTEN, MMP9, IL10, FOXP3, TBET, GATA3, CCL21, MX1, etc., using RT-PCR on PRRS Host Genetics Consortium (PHGC) samples representing different virus/weight categories. This information that will be used in conjunction with analyses collected on the same sample sets at Michigan State University and BARC. For the third objective, the University will help identify and provide samples collected from recent U.S. PRRS infections.
A new project was established to perform functional genomic analyses to determine response pathways that differ in porcine respiratory and the reproductive syndrome (PRRS) resistant versus susceptible PRRS Host Genetics Consortium (PHGC) pigs. ARS Researchers at Beltsville, MD have partnered with Purdue University scientists to use PHGC samples to assess whole blood gene expression responses to identify genes and pathways that are associated with pigs that clear PRRS virus (PRRSV) and that grow well despite PRRSV infection. With Michigan State University scientists multivariate statistical analyses of viral load and weight data have categorized PHGC pigs into 4 extreme categories including the most desirable, PRRS resistant low virus/high weight gain pigs and the worst, PRRS susceptible high virus/ low weight gain pigs. This statistical categorization of pigs from each PHGC trial provides a critical basis for selecting pigs and samples for detailed analyses of processes that control transcriptional and proteomic responses to PRRSV infection. To date, RNA samples have been prepared by ARS Researchers at Beltsville, MD from PHGC trial 1-4 for planned Pigoligoarray gene expression studies. In parallel Purdue University scientists will check for differential gene expression of targeted genes e.g., the PRRSV receptors and critical genes controlling immune anti-viral responses, using RT-PCR. As this work progresses we expect to develop predictive gene expression pathways and classifier genes that identify pigs which resist PRRSV infection and grow normally.
Disseminating progress on this grant was through regular email and phone contact, scheduled conference calls and yearly Consortium meeting with the participating labs discussing project plans, experimental design and reviewing data and presentation options.