Attaching and effacing (A/E) lesion formation by enteropathogenic E. coli on human intestinal mucosa is dependent on non-LEE effectors

PLoS Pathogens

Massiel Cepeda-Molero¹  Gad Frankel²  Stephanie Schüller³  Samuel J. Ellis³  Cedric N. Berger⁴  Alistair D. S. Walsham⁵  Simon Wemyss-Holden⁵  Luis Ángel Fernández⁵ 

[1]Department of Microbial Biotechnology. Centro Nacional de Biotecnología, CNB-CSIC. Darwin 3, Campus UAM, Cantoblanco, Madrid, Spain

[2]Department of Surgery, Norfolk and Norwich University Hospital NHS Foundation Trust, Norwich, United Kingdom

[3]Gut Health and Food Safety Programme, Quadram Institute Bioscience, Norwich, United Kingdom

[4]MRC Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Imperial College London, London, United Kingdom

[5]Norwich Medical School, University of East Anglia, Norwich, United Kingdom

关键词: Biopsy;    Gastrointestinal tract;    HeLa cells;    Mutant strains;    Actins;    Protein transport;    Epithelial cells;    Secretion systems;   

DOI  :  10.1371/journal.ppat.1006706

学科分类：生物科学（综合）

来源: Public Library of Science

【 摘 要 】

Enteropathogenic E. coli (EPEC) is a human pathogen that causes acute and chronic pediatric diarrhea. The hallmark of EPEC infection is the formation of attaching and effacing (A/E) lesions in the intestinal epithelium. Formation of A/E lesions is mediated by genes located on the pathogenicity island locus of enterocyte effacement (LEE), which encode the adhesin intimin, a type III secretion system (T3SS) and six effectors, including the essential translocated intimin receptor (Tir). Seventeen additional effectors are encoded by genes located outside the LEE, in insertion elements and prophages. Here, using a stepwise approach, we generated an EPEC mutant lacking the entire effector genes (EPEC0) and intermediate mutants. We show that EPEC0 contains a functional T3SS. An EPEC mutant expressing intimin but lacking all the LEE effectors but Tir (EPEC1) was able to trigger robust actin polymerization in HeLa cells and mucin-producing intestinal LS174T cells. However, EPEC1 was unable to form A/E lesions on human intestinal in vitro organ cultures (IVOC). Screening the intermediate mutants for genes involved in A/E lesion formation on IVOC revealed that strains lacking non-LEE effector/s have a marginal ability to form A/E lesions. Furthermore, we found that Efa1/LifA proteins are important for A/E lesion formation efficiency in EPEC strains lacking multiple effectors. Taken together, these results demonstrate the intricate relationships between T3SS effectors and the essential role non-LEE effectors play in A/E lesion formation on mucosal surfaces.

【 授权许可】

CC BY