Host cell interactions of outer membrane vesicle-associated virulence factors of enterohemorrhagic Escherichia coli O157: Intracellular delivery, trafficking and mechanisms of cell injury

Martina Bielaszewska (1) , Christian Rüter (2) , Andreas Bauwens (1) , Lilo Greune (2) , Kevin-André Jarosch , Daniel Steil (3) , Wenlan Zhang , Xiaohua He (4) , Roland Lloubès (5) , Angelika Fruth (6) , Kwang Sik K. S. Kim (7) , Alexander Schmidt , Ulrich Dobrindt (1) , Alexander Mellmann (1) , Helge Karch (1)

1 Institute for Hygiene
2 Institute of Infectiology, Center for Molecular Biology of Inflammation
3 Department of Physics and OPTIMAS Research Center
4 Western Regional Research Center
5 LISM - Laboratoire d'ingénierie des systèmes macromoléculaires
6 RKI - Robert Koch Institute [Berlin]
7 Div Pediat Infect Dis, Sch Med

Outer membrane vesicles (OMVs) are important tools in bacterial virulence but their role in the pathogenesis of infections caused by enterohemorrhagic Escherichia coli (EHEC) O157, the leading cause of life-threatening hemolytic uremic syndrome, is poorly understood. Using proteomics, electron and confocal laser scanning microscopy, immunoblotting, and bioassays, we investigated OMVs secreted by EHEC O157 clinical isolates for virulence factors cargoes, interactions with pathogenetically relevant human cells, and mechanisms of cell injury. We demonstrate that O157 OMVs carry a cocktail of key virulence factors of EHEC O157 including Shiga toxin 2a (Stx2a), cytolethal distending toxin V (CdtV), EHEC hemolysin, and flagellin. The toxins are internalized by cells via dynamin-dependent endo-cytosis of OMVs and differentially separate from vesicles during intracellular trafficking. Stx2a and CdtV-B, the DNase-like CdtV subunit, separate from OMVs in early endosomes. Stx2a is trafficked, in association with its receptor globotriaosylceramide within detergent-resistant membranes, to the Golgi complex and the endoplasmic reticulum from where the catalytic Stx2a A1 fragment is translocated to the cytosol. CdtV-B is, after its retrograde transport to the endoplasmic reticulum, translocated to the nucleus to reach DNA. CdtV-A and CdtV-C subunits remain OMV-associated and are sorted with OMVs to lysosomes. EHEC hemolysin separates from OMVs in lysosomes and targets mitochondria. The OMV-delivered CdtV-B causes cellular DNA damage, which activates DNA damage responses PLOS Pathogens |

Domaines: Interactions cellulaires [q-bio.CB]

Martina Bielaszewska, Christian Rüter, Andreas Bauwens, Lilo Greune, Kevin-André Jarosch, et al.. Host cell interactions of outer membrane vesicle-associated virulence factors of enterohemorrhagic Escherichia coli O157: Intracellular delivery, trafficking and mechanisms of cell injury. PLoS Pathogens, 2017, 13 (2), ⟨10.1371/journal.ppat.1006159⟩. ⟨hal-01788177⟩