Blood exposure induces global changes in gene expression and protein secretion of B. pertussis

This project was focused on transcriptome and secretome of pathogenic bacteria B. pertussis, which were cultivated on solid plates (charcoal agar) with/without blood and subsequently sub-cultured in liquid media. As a standard, Bordetella spp. strain are grown on agar plates supplemented with blood. The main aim of this project was to determine how the cells respond to blood exposure and how the blood treatment impacts on the gene expression profiles in cell inoculated from plates and subcultured in a blood-less medium. Gene expression profiles were analyzed by RNA-seq and proteins secreted by B. pertussis cells grown in liquid media were determined by LC-MS/MS technique. Our results indicate that B. pertussis cells exposed to blood secreted significantly higher amounts of several virulence factors including type III secretion system (T3SS), bifunctional hemolysin/adenylate cyclase CyaA and adhesin FhaS, compared to cells inoculated from plates without blood. Differences in secretion of T3SS needle complex, effector protein BopC and anti-sigma factor BtrA were at least an order of magnitude higher compared to the differences on the transcriptional level, suggesting that post-transcriptional regulation and/or regulation of the protein secretion plays an important role in modulating the function of T3SS in B. pertussis.