- 作者: Wen-Chun Huang, Chung-Yen Lin, Masayuki Hashimoto, Jiunn-Jong Wu, Ming-Cheng Wang, Wei-Hung Lin, Chang-Shi Chen and Ching-Hao Teng
- 作者服務機構: 1. Institute of Molecular Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan 2. Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan 3. Institute of Information Science, Academia Sinica, Taipei, Taiwan 4. Center of Infectious Disease and Signaling Research, National Cheng Kung University, Tainan, Taiwan 5. Department of Biotechnology and Laboratory Science in Medicine, School of Biomedical Science and Engineering, National Yang Ming University, Taipei, Taiwan 6. Department of Internal Medicine, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan 7. Department of Biochemistry and Molecular Biology, College of Medicine, National Cheng Kung University, Tainan, Taiwan 8. Center of Infectious Disease and Signaling Research, National Cheng Kung University, Tainan, Taiwan
- 中文摘要:
- 英文摘要:
Background
Extraintestinal pathogenic E. coli (ExPEC) remains one of the most prevalent bacterial pathogens that cause extraintestinal infections, including neonatal meningitis, septicemia, and urinary tract (UT) infections (UTIs). Antibiotic therapy has been the conventional treatment for such infections, but its efficacy has decreased due to the emergence of antibiotic-resistant bacteria. Identification and characterization of bacterial factors that contribute to the severity of infection would facilitate the development of novel therapeutic strategies. The ExPEC periplasmic protease Prc contributes to the pathogen’s ability to evade complement-mediated killing in the serum. Here, we further investigated the role of the Prc protease in ExPEC-induced UTIs and the underlying mechanism.
Methods
The uropathogenic role of Prc was determined in a mouse model of UTIs. Using global quantitative proteomic analyses, we revealed that the expression of FliC and other outer membrane-associated proteins was altered by Prc deficiency. Comparative transcriptome analyses identified that Prc deficiency affected expression of the flagellar regulon and genes that are regulated by five extracytoplasmic signaling systems.
Results
A mutant ExPEC with a prc deletion was attenuated in bladder and kidney colonization. Global quantitative proteomic analyses of the prc mutant and wild-type ExPEC strains revealed significantly reduced flagellum expression in the absence of Prc, consequently impairing bacterial motility. The prc deletion triggered downregulation of the flhDC operon encoding the master transcriptional regulator of flagellum biogenesis. Overexpressing flhDC restored the prc mutant’s motility and ability to colonize the UT, suggesting that the impaired motility is responsible for attenuated UT colonization of the mutant. Further comparative transcriptome analyses revealed that Prc deficiency activated the σE and RcsCDB signaling pathways. These pathways were responsible for the diminished flhDC expression. Finally, the activation of the RcsCDB system was attributed to the intracellular accumulation of a known Prc substrate Spr in the prc mutant. Spr is a peptidoglycan hydrolase and its accumulation destabilizes the bacterial envelope.
Conclusions
We demonstrated for the first time that Prc is essential for full ExPEC virulence in UTIs. Our results collectively support the idea that Prc is essential for bacterial envelope integrity, thus explaining how Prc deficiency results in an attenuated ExPEC. - 中文關鍵字:
- 英文關鍵字: Extraintestinal pathogenic Escherichia coli, Urinary tract infections, Protease Prc, Motility, Flagella, σE, Two-component signal transduction system RcsCDB, Spr