The role and related mechanism of the virulence factor TcpC of urinary tract pathogenic Escherichia coli in inhibiting neutrophil extracellular trap formation in mouse bone marrow cells
10.3760/cma.j.cn112309-20240726-00279
- VernacularTitle:尿路致病性大肠埃希菌毒力因子TcpC在抑制小鼠骨髓中性粒细胞胞外诱捕网形成中的作用及相关机制研究
- Author:
Jiaying FAN
1
;
Liming FAN
;
Weiyu JIANG
;
Ziwen XIE
;
Jiadong WANG
;
Ziyan JIANG
;
Qian OU
;
Jiaqi FANG
Author Information
1. 浙大城市学院医学院临床医学系，杭州 310015
- Publication Type:Journal Article
- Keywords:
Uropathogenic Escherichia coli;
TcpC;
Cystitis;
Mouse bone marrow neutrophils;
NETs
- From:
Chinese Journal of Microbiology and Immunology
2025;45(8):636-642
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To investigate the role of TcpC, a virulence factor of uropathogenic Escherichia coli (UPEC), in inhibiting the formation of neutrophil extracellular traps (NETs) in mouse bone marrow neutrophils, and to analyze its pathogenic mechanism. Methods:C57BL/6 mice were injected with either wild-type (CFT073 wt) or tcpc gene-knockout UPEC CFT073(CFT073 Δ tcpc) to establish a mouse model of cystitis. Mice were sacrificed 3 d post-infection, and their bladders were collected to observe gross pathological changes. Hematoxylin-eosin (HE) staining was used to assess histopathological changes in bladder tissues, and immunohistochemistry was performed to localize TcpC in bladder tissues. Bacterial loads in urine samples were quantified using the ten-fold dilution method, and the presence of tcpc gene in genomic DNA from bladder or urine samples was confirmed by PCR. The expression of TcpC at mRNA and protein levels in mouse bone marrow nuetrophils infected with CFT073 wt was detected by qRT-PCR and Western blot. The effects of UPEC infection on expression of NETs-related proteins and the production of pro-inflammatory factors in mouse bone marrow neutrophils were analyzed by Western blot and ELISA, respectively. Reactive oxygen species(ROS) level and bacterial viability in mouse bone marrow nuetrophils were measured using ROS and bacterial viability detection kits. Results:Compared to the CFT073 Δ tcpc group, the bladder of CFT073 wt group mice exhibited significant enlargement, extensive inflammatory cell infiltration, and the presence of TcpC in bladder tissue. The bacterial load in the urine of CFT073 wt -infected mice was significantly higher than that in the CFT073 Δ tcpc group ( P<0.01). PCR confirmed the presence of the tcpc gene in bladder and urine samples from CFT073 wt-infected mice. Increased expression of TcpC at both mRNA and protein levels was observed in CFT073 wt-infected mouse bone marrow neutrophils. CFT073 wt infection inhibited the mRNA and protein expression of NETs-related proteins and reduced the production of pro-inflammatory factors in mouse bone marrow neutrophils. TcpC suppressed ROS level and promoted the survival of CFT073 wt in mouse bone marrow neutrophils. Conclusions:TcpC enhances the pathogenicity of UPEC CFT073 by inhibiting the formation and activation of NETs in mouse bone marrow neutrophils. This study provides new insights into the pathogenic mechanisms of UPEC and the immune evasion strategies of other pathogenic bacteria, as well as potential targets for clinical prevention and treatment of UPEC-induced urinary tract infections.
