Threading the Needle: Small-Molecule Targeting of a Xenobiotic Receptor to Ablate Escherichia coli Polysaccharide Capsule Expression Without Altering Antibiotic Resistance.


Journal Article

BACKGROUND: Uropathogenic Escherichia coli (UPEC), a leading cause of urinary tract and invasive infections worldwide, is rapidly acquiring multidrug resistance, hastening the need for selective new anti-infective agents. Here we demonstrate the molecular target of DU011, our previously discovered potent, nontoxic, small-molecule inhibitor of UPEC polysaccharide capsule biogenesis and virulence. METHODS: Real-time polymerase chain reaction analysis and a target-overexpression drug-suppressor screen were used to localize the putative inhibitor target. A thermal shift assay quantified interactions between the target protein and the inhibitor, and a novel DNase protection assay measured chemical inhibition of protein-DNA interactions. Virulence of a regulatory target mutant was assessed in a murine sepsis model. RESULTS: MprA, a MarR family transcriptional repressor, was identified as the putative target of the DU011 inhibitor. Thermal shift measurements indicated the formation of a stable DU011-MprA complex, and DU011 abrogated MprA binding to its DNA promoter site. Knockout of mprA had effects similar to that of DU011 treatment of wild-type bacteria: a loss of encapsulation and complete attenuation in a murine sepsis model, without any negative change in antibiotic resistance. CONCLUSIONS: MprA regulates UPEC polysaccharide encapsulation, is essential for UPEC virulence, and can be targeted without inducing antibiotic resistance.

Full Text

Cited Authors

  • Arshad, M; Goller, CC; Pilla, D; Schoenen, FJ; Seed, PC

Published Date

  • April 15, 2016

Published In

Volume / Issue

  • 213 / 8

Start / End Page

  • 1330 - 1339

PubMed ID

  • 26671885

Pubmed Central ID

  • 26671885

Electronic International Standard Serial Number (EISSN)

  • 1537-6613

Digital Object Identifier (DOI)

  • 10.1093/infdis/jiv584


  • eng

Conference Location

  • United States