Project description:Uropathogenic Escherichia coli (UPEC) are capable of occupying physiologically distinct intracellular and extracellular niches within the urinary tract. This feat requires the timely regulation of gene expression and small RNAs (sRNAs) are known to mediate such rapid adjustments in response to changing environmental cues. This study aimed to uncover sRNA-mediated gene regulation in the UPEC strain UTI89, during infection of bladder epithelial cells. Hfq is an RNA chaperone known to facilitate and stabilize sRNA and target mRNA interactions with bacterial cells. The co-immunoprecipitation and high throughput RNA sequencing of Hfq bound sRNAs performed in this study, revealed distinct sRNA profiles in UPEC in the extracellular and intracellular environments. Our findings emphasize the importance of studying regulatory sRNAs in a biologically relevant niche. This strategy also led to the discovery of a novel virulence-associated trans-acting sRNA-PapR. Deletion of papR was found to enhance adhesion of UTI89 to both bladder and kidney cell lines in a manner independent of type-1 fimbriae. We demonstrate PapR mediated posttranscriptional repression of the P-fimbriae phase regulator gene papI and postulate a role for such regulation in fimbrial cross-talk at the population level in UPEC. Our results further implicate the Leucine responsive protein (LRP) as a transcriptional activator regulating PapR expression. Our study reports, for the first time, a role for sRNAs in regulation of P-fimbriae phase variation and emphasizes the importance of studying pathogenesis-specific sRNAs within a relevant biological niche.
Project description:Urinary tract infections (UTIs) are a very common bacterial infectious disease in humans, and uropathogenic Escherichia coli (UPEC) are the most frequent cause of UTIs. During infection, UPEC must cope with a variety of stressful conditions in the urinary tract. Here, we demonstrated that the small RNA (sRNA) RyfA of UPEC strains was required for resistance to oxidative and osmotic stresses. Inactivation of ryfA in UPEC strain CFT073 decreased urinary tract colonization in CBA/J mice and the ryfA mutant also had reduced production of type 1 and P fimbriae, which are known to be important for UTI. Transcriptomic analysis of the ryfA mutant showed changes in expression of genes associated with general stress responses, metabolism, biofilm formation and genes coding for cell surface proteins. Furthermore, loss of ryfA also reduced UPEC survival in human macrophages. Thus, ryfA plays a key regulatory role in UPEC adaptation to stress, that contributes to UTI and survival in macrophages.
Project description:Transcriptional analysis of UTI89 - uropathogenic E.coli (UPEC) strain grown in urine/Luria bertani medium culture in vitro as well as during three distinct phases of UPEC bladder infection: intracellular growth, filament formation and filament reversal. UTI89 was used to infect a bladder epithelial cell line cultured within a dynamic flow chamber system and harvested at particular stages of its pathogenecity cascade. Total RNA was processed and cy3 labeled for microarray analysis using Agilent custom Escherichia coli UTI89 arrays designed using E-Array.
Project description:DNA microarrays were used to provide a global transcriptional profile of S. typhimurium during the intracellular growth phase of infection pathogenesis following infection of macrophages.
Project description:We previously determined that loss of respiratory quinol oxidase cytochrome bd disrupts biofilm formation in uropathogenic Escherichia coli (UPEC). In this study, we extracted and interrogated the outer membrane and extracellular matrix of colony biofilms formed by UPEC isolate UTI89 and an isogenic mutant lacking cytochrome bd (∆cydAB).
Project description:Growth in urine of cranberry extract-treated volunteers did not markedly affect the transcirptome of UPEC strain UTI89. Expression of bacterial adhesin determinants (P fimbriae, S fimbrae, curli) was not markedly changed upon growth in the urine samples, while a slight, but non-significant upregulation of type 1 fimbriae was observed.
Project description:To understand the functions of Pf1 sRNA in response to temperature changes, a knockout mutant (ΔPf1) was constructed. Transcriptomics and proteomics were performed on biological triplicates of the wild strain and ΔPf1 grown to stationary phase at 4°C and 32°C. The file uploaded is the original data of proteomics.
