Pilicide ec240 disrupts virulence circuits in uropathogenic Escherichia coli.
Bottom Line: Furthermore, the effect of ec240 on motility was abolished in the absence of the SfaB, PapB, SfaX, and PapX regulators.In contrast to the effects of ec240, deletion of the type 1 pilus operon led to increased S and P piliation and motility.Thus, ec240 dysregulated several uropathogenic Escherichia coli (UPEC) virulence factors through different mechanisms and independent of its effects on type 1 pilus biogenesis and may have potential as an antivirulence compound.
Affiliation: Department of Molecular Microbiology and Microbial Pathogenesis and Center for Women's Infectious Disease Research, Washington University School of Medicine in St. Louis, St. Louis, Missouri, USA.Show MeSH
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Mentions: We assessed the transcriptional profile of UTI89 grown with 250 µM ec240 or a dimethyl sulfoxide (DMSO) vehicle control to investigate the global effects of ec240 on UPEC biology. We utilized a relatively high concentration of ec240 in order to detail all possible “off-target” effects. RNA-Seq was conducted on triplicate biological samples grown under type 1 pilus-inducing conditions. We identified 52 gene transcripts that were altered ≥3-fold when UTI89 was grown in ec240 rather than the DMSO vehicle control. Of these 52 genes, 15 had decreased transcript levels and 37 had increased transcript levels. The transcript levels of CUP pilus genes were affected by the pilicide ec240, as were the transcript levels of genes with a variety of different functions, including motility, siderophore synthesis and transport, metabolism, translation, gene regulation, and stress response (Fig. 2A). There were also some hypothetical genes with dysregulated transcript levels (Fig. 2A). As shown in the MA plot (a plot of the log2 of the ratio of abundances of each transcript between the two conditions [M] plotted against the average log2 of abundance of that transcript in both conditions [A]), the pap and sfa genes encoding P and S pili had the most upregulated transcript levels, while the fim and flg genes encoding type 1 pili and flagella had the most downregulated transcript levels (Fig. 2B), with fim transcripts downregulated 8- to 17-fold, pap transcripts upregulated 4- to 49-fold, and sfa transcripts upregulated 4- to 25-fold (Fig. 2C). Furthermore, CUP operon genes cumulatively make up 46% of the genes dysregulated by >3-fold but 76% of the genes dysregulated by >10-fold after growth in ec240. This indicates that under type 1 pilus-inducing conditions, the major effect of ec240 is the dysregulation of CUP pili.
Affiliation: Department of Molecular Microbiology and Microbial Pathogenesis and Center for Women's Infectious Disease Research, Washington University School of Medicine in St. Louis, St. Louis, Missouri, USA.