Characterization of the inflammatory phenotype of Mycobacterium avium subspecies paratuberculosis

Understanding the pathogenic mechanisms and host responses to Johne's disease, caused by Mycboacterium avium subspecies paratuberculosis (MAP), is complicated by a number of challenges of the disease progression and lack of ex vivo models to study the disease. We describe novel cell culture passage model which mimics the course of infection in vivo. Using this model we determined that cell culture passaged MAP develops an inflammatory phenotype initiating higher levels of pro-inflammatory cytokines and chemokines compared to levels initiated by non-passaged MAP. To verify that the MAP phenotypes were changing, we conducted transcriptome analysis of each population during the passage model and identified a change in gene expression, specifically and upregulation of genes involved in the biosynthesis of lipid components within the cell. Lipidomic analysis showed dramatically different lipid profiles between the 2 populations. These transcriptome changes were validated by the identification of high levels of upregulated transcripts from MAP-infected cattle ileal tissue. In total, this study described a novel model used to show that MAP changes phenotype during intracellular passage, thus changing its lipid profile and triggering an inflammatory response in the host leading to the severe clinical phage of Johne's disease. In total 6 slides were analyzed. Of the 2 phenotypes under investigation, the P0 samples (non-inflammatory) were analyzed in triplate and the P2 samples (inflammatory) were analyzed in triplicate. Each slide fluorescence intensity was measured at PMT400, 600 and 750. Each oligo on each slide was spotted in triplicate and each slide had its own internal controls.