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New aspects of RpoE in uropathogenic Proteus mirabilis.
- Source :
-
Infection and immunity [Infect Immun] 2015 Mar; Vol. 83 (3), pp. 966-77. Date of Electronic Publication: 2014 Dec 29. - Publication Year :
- 2015
-
Abstract
- Proteus mirabilis is a common human pathogen causing recurrent or persistent urinary tract infections (UTIs). The underlying mechanisms for P. mirabilis to establish UTIs are not fully elucidated. In this study, we showed that loss of the sigma factor E (RpoE), mediating extracytoplasmic stress responses, decreased fimbria expression, survival in macrophages, cell invasion, and colonization in mice but increased the interleukin-8 (IL-8) expression of urothelial cells and swarming motility. This is the first study to demonstrate that RpoE modulated expression of MR/P fimbriae by regulating mrpI, a gene encoding a recombinase controlling the orientation of MR/P fimbria promoter. By real-time reverse transcription-PCR, we found that the IL-8 mRNA amount of urothelial cells was induced significantly by lipopolysaccharides extracted from rpoE mutant but not from the wild type. These RpoE-associated virulence factors should be coordinately expressed to enhance the fitness of P. mirabilis in the host, including the avoidance of immune attacks. Accordingly, rpoE mutant-infected mice displayed more immune cell infiltration in bladders and kidneys during early stages of infection, and the rpoE mutant had a dramatically impaired ability of colonization. Moreover, it is noteworthy that urea (the major component in urine) and polymyxin B (a cationic antimicrobial peptide) can induce expression of rpoE by the reporter assay, suggesting that RpoE might be activated in the urinary tract. Altogether, our results indicate that RpoE is important in sensing environmental cues of the urinary tract and subsequently triggering the expression of virulence factors, which are associated with the fitness of P. mirabilis, to build up a UTI.<br /> (Copyright © 2015, American Society for Microbiology. All Rights Reserved.)
- Subjects :
- Animals
Epithelial Cells drug effects
Epithelial Cells pathology
Female
Fimbriae, Bacterial genetics
Fimbriae, Bacterial metabolism
Humans
Interleukin-8 biosynthesis
Interleukin-8 metabolism
Lipopolysaccharides pharmacology
Mice
Mice, Inbred C57BL
Mutation
Polymyxin B pharmacology
Promoter Regions, Genetic drug effects
Proteus Infections immunology
Proteus Infections pathology
Proteus mirabilis drug effects
Proteus mirabilis immunology
Proteus mirabilis pathogenicity
Recombinases genetics
Recombinases metabolism
Sigma Factor deficiency
Sigma Factor metabolism
Urea pharmacology
Urinary Tract Infections immunology
Urinary Tract Infections pathology
Urothelium drug effects
Urothelium microbiology
Urothelium pathology
Virulence
Epithelial Cells microbiology
Gene Expression Regulation, Bacterial
Proteus Infections microbiology
Proteus mirabilis genetics
Sigma Factor genetics
Urinary Tract Infections microbiology
Subjects
Details
- Language :
- English
- ISSN :
- 1098-5522
- Volume :
- 83
- Issue :
- 3
- Database :
- MEDLINE
- Journal :
- Infection and immunity
- Publication Type :
- Academic Journal
- Accession number :
- 25547796
- Full Text :
- https://doi.org/10.1128/IAI.02232-14