title: Potential novel antibiotics from HTS targeting the virulence-regulating transcription factor, VirF, from Shigella flexneri.
abstract: VirF is an AraC-type transcriptional regulator responsible for activating the transcription of virulence genes required for the intracellular invasion and cell-to-cell spread of Shigella flexneri. Gene disruption studies have validated VirF as a potential target for an anti-virulence therapy to treat shigellosis by determining that VirF is necessary for virulence, but not required for bacterial viability. Using a bacteria-based, β-galactosidase reporter assay we completed a high-throughput screening (HTS) campaign monitoring VirF activity in the presence of over 140,000 small molecules. From our screening campaign, we identified five lead compounds to pursue in tissue culture-based invasion and cell-to-cell spread assays, and toxicity screens. Our observations of activity in these models for infection have validated our approach of targeting virulence regulation and have allowed us to identify a promising chemical scaffold from our HTS for hit-to-lead development. Interestingly, differential effects on invasion versus cell-to-cell spread suggest that the compounds' efficacies may depend, in part, on the specific promoter that VirF is recognizing.
authors.affiliation: Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, Ann Arbor, MI, USA.
authors.forename: Anthony A
authors.initials: AA
authors.lastname: Emanuele
authors.affiliation: Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, MD, USA.
authors.forename: Nancy E
authors.initials: NE
authors.lastname: Adams
authors.affiliation: Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, Ann Arbor, MI, USA.
authors.forename: Yi-Chen
authors.initials: YC
authors.lastname: Chen
authors.affiliation: Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, MD, USA.
authors.forename: Anthony T
authors.initials: AT
authors.lastname: Maurelli
authors.affiliation: Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, Ann Arbor, MI, USA.
authors.forename: George A
authors.initials: GA
authors.lastname: Garcia
mesh_terms: D000465:Algorithms; D000900:Anti-Bacterial Agents / Q000302:isolation & purification / Q000494:pharmacology*; D003627:Data Interpretation, Statistical; D017930:Genes, Reporter / Q000235:genetics; D006367:HeLa Cells; D057166:High-Throughput Screening Assays / Q000379:methods*; D006801:Humans; D007202:Indicators and Reagents; D050835:Interferon Regulatory Factors / Q000187:drug effects*; D008826:Microbial Sensitivity Tests; D010957:Plasmids / Q000235:genetics; D015203:Reproducibility of Results; D012763:Shigella flexneri / Q000187:drug effects* / Q000235:genetics / Q000254:growth & development; D014764:Viral Proteins / Q000187:drug effects*; D014774:Virulence / Q000235:genetics; D037521:Virulence Factors; D001616:beta-Galactosidase / Q000235:genetics
chemical_list: D000900:Anti-Bacterial Agents; D007202:Indicators and Reagents; D050835:Interferon Regulatory Factors; D014764:Viral Proteins; D037521:Virulence Factors; C413486:viral interferon regulatory factors; D001616:beta-Galactosidase