Abstract
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.
Original language | English (US) |
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Pages (from-to) | 1330-1339 |
Number of pages | 10 |
Journal | Journal of Infectious Diseases |
Volume | 213 |
Issue number | 8 |
DOIs | |
State | Published - Apr 15 2016 |
Funding
This work was supported by the Eunice Kennedy Shriver National Institute of Child Health (K12HD000850 and K12-HD043494 to M. A.), the Department of Defense (W81XWH-13-1-0450 to P. C. S.), the National Institutes of Health and the US Department of Health and Human Services (NIGMS 1R01GM108494-01 to P. C. S., NHGRI 5U54HG005031 to Jeffrey Aub\u00E9, PI), the March of Dimes (6-FY12-277 to P. C. S.), the Christopher and Dana Reeve Foundation (to P. C. S.), and the Paralyzed Veterans of America (to P. C. S.).
Keywords
- E. Coli
- multidrug efflux pumps
- polysaccharide capsule
- small-molecule capsule inhibitor
ASJC Scopus subject areas
- General Medicine