The roles of cAMP receptor protein in uropathogenic Proteus mirabilis

• Main Authors: Yi-Lin Tsai, 蔡易霖
• Other Authors: 廖淑貞
• Format: Others
• Language: zh-TW
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/a2253j

博士 === 國立臺灣大學 === 醫學檢驗暨生物技術學研究所 === 105 === Introduction: Proteus mirabilis is a common human pathogen causing recurrent or persistent urinary tract infections (UTIs), especially in patients with indwelling catheters. The underlying mechanisms for P. mirabilis to establish UTIs are still not fully elucidated. The ability of P. mirabilis to colonize within the host urinary tract is closely related to fimbria-mediated adhesion. Previously, we found a conserved cAMP receptor protein, Crp, is involved in the carbon metabolism of P. mirabilis. Many studies have shown that the Crp is also associated with virulence factor production in pathogenic bacteria. Specific aims: we investigated the roles of Crp in uropathogenic Proteus mirabilis. Results: In this work, we first demonstrated that alteration of Crp activity was in response to glucose. Then we investigate the correlation of Crp with major glucose PTS transporter gene ptsG, adenylate cyclase gene cyaA and Hfq by XylE reporter assay and real-time RT-PCR. The results indicate that the Crp-cAMP increased ptsG and its own gene mRNA level, and decreased cyaA and hfq mRNA level. In addition, we found the loss of crp increased kidney colonization and survival in macrophages. Transcriptome analysis revealed Crp-regulated genes. The candidate genes were validated by real-time PCR and reporter assay. We found that Crp could regulate multiple virulence factors, including Pmp fimbriae, flagellin, stress (acid or H2O2) tolerance, and modulation of host immune responses, which may contribute to colonization in mice. Conclusion: For the first time, we found upregulation of Pmp fimbriae in crp mutant is critical to the kidney colonization. In this regard, it is tempting to suggest that Pmp fimbriae may serve as the target for design of novel drugs for diabetic Proteus infection.