| Today, we are faced with the challenges of fighting infectious organisms that have either been neglected or have developed ways to resist current treatments. Longstanding public health problems, such as tuberculosis, have evolved into mulitdrug-resistant bacilli, tolerant to current drug regimens. In addition, neglected diseases such as F. tularensis have concerns regarding their use in bioterrorism. Current research initiatives search for novel chemotherapeutics to alternative targets in order to resolve the problem of resistance and the continued battle against infectious disease. The research presented utilizes both genomic and structure-based approaches to identify new drug targets for Mycobacterium tuberculosis and optimize a series of diphenyl ether compounds with specific inhibitory activity against ftuFabI, the enoyl ACP-reductase enzyme of Francisella tularensis.;Structure-based design efforts have provided a lead diphenyl ether compound, 5-hexyl-2-phenoxyphenol (SBPT04), demonstrating high affinity enzyme inhibitory activity, in vitro bactericidal activity, and in vivo efficacy against F. tularensis in the murine model of infection by both intraperitoneal (i.p.) and oral (p.o.) routes. SBPT04 cleared infection by day 4 of treatment (200mg/kg/dose) with 100% survival rates and no relapse of disease for over 30 days by i.p. delivery. Oral delivery exhibited delayed dissemination with significant efficacy. Pharmacokinetic analysis revealed sufficient bioavailability upon i.p. delivery. In vitro metabolism studies suggested limited phase I oxidation with phase II O-glucuronide as the primary metabolite. In addition to being a potent lead, this work establishes diphenyl ethers as a platform for the development of broad-spectrum agents to other pathogens in addition to tularemia.;Genomic-based strategies were used to identify novel drug targets involved in cell cycle regulatory events of Mycobacterium tuberculosis. Homologues to proteins involved in SOS responses and min-system regulation that direct cell division events were identified and characterized via morphological changes and gene expression profiles induced by gene dosage experiments. Transcriptional responses revealed connections between cells that have stopped dividing with conditions defined for bacilli in a nonreplicating persistent state. Understanding regulatory events of cell cycle progression and identifying specific players will allow the design of compounds, which may either prevents bacteria from entering a nonreplicating persistence or regulate the events of reactivation. |
