E.coli HPI promotes enteritis by inducing pyroptosis through NLRP3/caspase-1 signaling pathway
10.3969/j.issn.1000-4718.2024.10.001
- VernacularTitle:E.coli HPI通过NLRP3/caspase-1信号通路诱导细胞焦亡而促进肠道炎症
- Author:
Jingsong ZHANG
1
;
Chunlan SHAN
;
Hao WANG
;
Tianling PAN
;
Jue SHEN
;
Jinlong XIAO
;
Ru ZHAO
;
Peng XIAO
;
Hong GAO
Author Information
1. 云南农业大学动物医学院,云南 昆明 650201
- Keywords:
Escherichia coli;
high-pathogenicity island;
pyroptosis;
NLRP3/caspase-1 signaling pathway
- From:
Chinese Journal of Pathophysiology
2024;40(10):1777-1787
- CountryChina
- Language:Chinese
-
Abstract:
AIM:This study aims to explore the impact of Escherichia coli(E.coli)high-pathogenicity island(HPI)on pyroptosis and intestinal inflammation.METHODS:Kunming mice and IPEC-J2 cells(porcine small intesti-nal epithelial cells)were treated with HPI-containing E.coli strain(HPI+),HPI-deleting E.coli strain(ΔHPI),or lipo-polysaccharide(LPS).The intestinal lactate dehydrogenase(LDH)activity,superoxide dismutase(SOD)activity,IgA expression and secretory IgA(SIgA)content were assessed in mice.The expression of key regulatory factors in the nucleo-tide-binding oligomerization domain-like receptor protein 3(NLRP3)/caspase-1 signaling pathway-related proteins in mouse intestinal tract and IPEC-J2 cells was analyzed by RT-qPCR,immunohistochemical staining and Western blot.The levels of interleukin-1β(IL-1β)and IL-18 in mouse serum and IPEC-J2 cell culture supernatants were measured by ELISA.The pivotal role of NLRP3 in HPI+infection was confirmed by silencing NLRP3 in IPEC-J2 cells using siRNA.RE-SULTS:The HPI+infection markedly decreased SOD activity,increased IgA+B cell count,and induced the LDH release and SIgA secretion in the mouse intestine compared with ΔHPI infection.The results of ELISA,HE staining and TUNEL staining indicated that E.coli HPI triggered DNA damage,tissue injury and inflammation in mouse intestinal epithelial cells.Western blot revealed an increase in intestinal gasdermin D N-terminal fragment(GSDMD-N)protein level with HPI+infection compared with ΔHPI infection.E.coli HPI significantly up-regulated mRNA and protein expression of NLRP3,apoptosis-associated speck-like protein containing a caspase recruitment domain(ASC),caspase-1,GSDMD,IL-1β and IL-18 in mouse intestinal tissues and IPEC-J2 cells,accompanied by the elevated secretion of IL-1β and IL-18.The confo-cal microscopy demonstrated an enhanced assembly of the NLRP3 inflammasome with HPI+infection compared with ΔHPI infection,leading to colocalization of NLRP3 and caspase-1.Furthermore,NLRP3 silencing in IPEC-J2 cells attenuated E.coli HPI-induced cell inflammation,damage,and NLRP3/caspase-1 signaling pathway activation.CONCLUSION:The presence of HPI enhances the virulence of E.coli and exacerbates intestinal inflammation.Moreover,pyroptosis,regu-lated by the NLRP3/caspase-1 signaling pathway,plays a pivotal role in the intestinal injury induced by E.coli HPI.
