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New Aspects of RpoE in Uropathogenic Proteus mirabilis
- Source :
- Infection and Immunity. 83:966-977
- Publication Year :
- 2015
- Publisher :
- American Society for Microbiology, 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.
- Subjects :
- Lipopolysaccharides
Immunology
Fimbria
Swarming motility
Virulence
Sigma Factor
Biology
Microbiology
Recombinases
Mice
Sigma factor
medicine
Animals
Humans
Urea
Promoter Regions, Genetic
Proteus mirabilis
Polymyxin B
Regulation of gene expression
Interleukin-8
Wild type
Epithelial Cells
Gene Expression Regulation, Bacterial
Bacterial Infections
biology.organism_classification
Mice, Inbred C57BL
Infectious Diseases
Fimbriae, Bacterial
Mutation
Urinary Tract Infections
Female
Parasitology
Urothelium
Proteus Infections
medicine.drug
Subjects
Details
- ISSN :
- 10985522 and 00199567
- Volume :
- 83
- Database :
- OpenAIRE
- Journal :
- Infection and Immunity
- Accession number :
- edsair.doi.dedup.....2665445a09ea006c6c9c7a1cd50b79f4