Role of type VI secretion in Burkholderia pseudomallei virulence and host interaction

• Applicant: Dr. Sandra Schwarz
• Subject Area: Parasitology and Biology of Tropical Infectious Disease Pathogens
• Term: from 2009 to 2011
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 157002098

Burkholderia pseudomallei is the etiological agent of melioidosis, a serious invasive infection of humans and animals. The genome of B. pseudomallei harbours six gene clusters that encode apparent type VI secretion systems (T6SS) whose function is unknown. T6SSs are recently described protein export machines that release substrates into the extracellular milieu and into the cytosol of host cells. Emerging data demonstrate a crucial role for T6SSs in the interactions of many pathogenic and symbiotic bacteria with their hosts. The first aim of this project is to conduct a systematic analysis of the role of each predicted T6SS of B. pseudomallei in virulence. We will begin by generating strains bearing in-frame mutations that inactivate each T6SS. These strains will be analyzed for virulence in a murine model of acute pneumonic melioidosis. The second aim is to comprehensively investigate the mechanism-ofaction of those T6SSs that play demonstrable roles in B. pseudomallei pathogenesis. To this end the effect of a given T6SS on bacterial cellular processes will be examined via bacterial phenotype microarrays. A series of cell culture infection assays will be used to measure the contribution of a given T6SS to cytotoxicity, invasion, replication and phagosomal escape within relevant host cell types. In addition, we will pursue a microarray approach to characterize global T6S-dependent effects on host cell response. The experiments proposed herein will provide important new insights into the mechanism by which T6S influences the interaction between B. pseudomallei and its host. This project will also serve as a crucial step towards understanding basic aspects of B. pseudomallei pathogenesis.

• DFG Programme: Research Fellowships
• International Connection: USA
• Host: Professor Joseph Mougous, Ph.D.