Induction of phagocytic behaviour in human epithelial cells by Escherichia coli cytotoxic necrotizing factor type 1.
Cytotoxic necrotizing factor type 1 (CNF1) from strains of pathogenic Escherichia coli induces in human epithelial HEp-2 cells, a profound reorganization of the actin cytoskeleton into prominent stress fibres and membrane ruffles. We report here that this process is associated with induction of phagocytic-like activity. CNF1-treated cells acquired the ability to ingest latex beads as well as non-invasive bacteria such as Listeria innocua, which were taken as a model system. Uptake of bacteria was similar to pathogen-induced phagocytosis, since L. innocua transformed with DNA coding for the pore-forming toxin listeriolysin O behaved, with respect to intracellular growth, like the invasive, pathogenic species L. monocytogenes. Our results raise the possibility that, in vivo, pathogenic CNF1-producing E. coli may invade epithelia by this novel induced phagocytic-like mechanism.
Falzano
L
L
Unité des Toxines Microbiennes, URA CNRS, Paris, France.
Fiorentini
C
C
Donelli
G
G
Michel
E
E
Kocks
C
C
Cossart
P
P
Cabanié
L
L
Oswald
E
E
Boquet
P
P
D008841:Actin Cytoskeleton / Q000187:drug effects / Q000648:ultrastructure; D000199:Actins / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D001427:Bacterial Toxins / Q000302:isolation & purification / Q000494:pharmacology*; D002460:Cell Line; D015638:Cytochalasin D / Q000494:pharmacology; D003603:Cytotoxins / Q000302:isolation & purification / Q000494:pharmacology*; D004848:Epithelium / Q000187:drug effects / Q000382:microbiology / Q000502:physiology; D004926:Escherichia coli / Q000472:pathogenicity / Q000502:physiology*; D029968:Escherichia coli Proteins; D006801:Humans; D007700:Kinetics; D008087:Listeria / Q000472:pathogenicity* / Q000502:physiology; D008855:Microscopy, Electron, Scanning; D010587:Phagocytosis / Q000187:drug effects*
D000199:Actins; D001427:Bacterial Toxins; D003603:Cytotoxins; D029968:Escherichia coli Proteins; C060296:cytotoxic necrotizing factor type 1; D015638:Cytochalasin D