The N-terminal domain of EspF induces host cell apoptosis after infection with enterohaemorrhagic Escherichia coli O157:H7

• Published in: PloS one 2013-01, Vol.8 (1), p.e55164-e55164
• Main Authors: Zhao, Suhui, Zhou, Ying, Wang, Chunhui, Yang, Yu, Wu, Xianbo, Wei, Yao, Zhu, Li, Zhao, Wei, Zhang, Qiwei, Wan, Chengsong
• Format: Article
• Language: English
• Subjects: Actin; Adhesive strength; Animals; Apoptosis; Apoptosis - genetics; Bacteria; Bacterial Adhesion - genetics; Bacterial Secretion Systems; Biology; Carrier Proteins - chemistry; Carrier Proteins - genetics; Carrier Proteins - metabolism; Caspase; Caspase-9; Cell adhesion; Cell Line; Citrobacter; Clonal deletion; Colonization; Cytoskeleton; Deficient mutant; Dehydrogenases; E coli; Epithelial cells; Escherichia coli; Escherichia coli Infections - metabolism; Escherichia coli O157 - genetics; Escherichia coli O157 - metabolism; Escherichia coli O157 - pathogenicity; Escherichia coli Proteins - chemistry; Escherichia coli Proteins - genetics; Escherichia coli Proteins - metabolism; Gene deletion; Health aspects; Heat shock proteins; Host-Pathogen Interactions; Hsp70 protein; Infection; Infections; Intestine; Kinases; L-Lactate dehydrogenase; Lactate dehydrogenase; Lactic acid; Lesions; Medicine; Membrane Potential, Mitochondrial; Mice; Mice, Inbred BALB C; Mitochondria; Mitochondria - metabolism; Mucosa; Muscle proteins; Mutation; Pathogenesis; Pathogens; Protein binding; Protein Interaction Domains and Motifs; Proteins; Public health; Secretion; Studies; Survival; Virulence - genetics
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0055164

Enterohemorrhagic Escherichia coli (EHEC) employs a type III secretion system (TTSS) to export the translocator and effector proteins required for mucosal colonization. As an important bacterial effector protein in locus of enterocyte effacement four, the EspF protein causes F-actin filament aggregations to form attaching and effacing (A/E) lesions, and induces the destruction of brush-border microvilli and cytoskeletal rearrangements to form pedestals. However, the molecular pathogenesis of A/E lesions due to EHEC O157:H7 infection is unclear. In this study, we constructed an espF-deficient mutant (ΔespF) with a 162-bp deletion in the N-terminal domain by using overlap extension PCR. The results showed that EHEC EspF translocated into intestinal epithelial cells, targeted mitochondria and induced apoptosis. The ΔespF mutant, compared to EHEC prototype Guangzhou strain, had lower cell attachment and effacement abilities, lower caspase-9/3 and lactate dehydrogenase levels, lower bacterial adhesion, weaker mitochondria apoptosis, and a higher mouse survival rate. Our results demonstrate the probable function of the EspF N-terminal domain, which targets mitochondria and binds mitochondria heat shock protein 70 to induce cell apoptosis via A/E lesions. These findings may be invaluable in clarifying the molecular pathogenesis of EspF of EHEC O157:H7.