BioProject

Francisella tularensis is classified as a Category A priority pathogen and causes fatal disseminated disease in humans upon inhalation of less than 50 bacteria. More...

Francisella tularensis is classified as a Category A priority pathogen and causes fatal disseminated disease in humans upon inhalation of less than 50 bacteria. Although drugs are available for treatment, they are not ideal because of toxicity and delivery, and in some cases relapse upon withdrawal. We have an ongoing program in the development of novel FabI enoyl-ACP-reductase enzyme inhibitors for Francisella and other select agents. To establish ftFabI in F. tularensis as a clinically relevant drug target, we demonstrated that the enzyme is essential for growth in vitro and that ftfabI is not transcriptionally altered in the presence of exogenous fatty acids. Inhibition of ftFabI results in loss of viability that is not rescued by exogenous fatty acids supplementation. Importantly, whole-genome transcriptional profiling of F. tularensis with DNA microarrays from infected tissues revealed that ftfabI and de novo fatty acid biosynthetic genes are transcriptionally active during infection. This is the first demonstration that the FabI enoyl-ACP-reductase enzyme encoded by F. tularensis is essential and that de novo fatty acid biosynthetic components are transcriptionally active during infection in the mouse model tularemia. Overall design: 2 C57BL/6 mice were infected with Francisella tularensis strain Schu4 via the intranasal route. Spleen tissue was harvested at 120 hours post-infection and total RNA was isolated immediately after harvest. RNA was pooled and host polyA-tailed RNA and ribosomal RNA were depleted using hybridization probes coupled to magnetic beads. The resulting sample was enriched for bacterial mRNA, and dye labeled using random hexamer primed RT and Cy3-labeled dUTPs. Labeled cDNA was hybridized in triplicate to custom whole genome cDNA microarrays and scanned using a GenePix 4000B. Less...