Hinderance of apoptosis and phagocytic behaviour induced by Escherichia coli cytotoxic necrotizing factor 1: two related activities in epithelial cells.

Several microbial factors are recognized able to modulate apoptosis. In this work, we analyze the activity of a toxin from pathogenic strains of Escherichia coli, the Cytotoxic Necrotizing Factor 1 (CNF1), which influences epithelial cell structure and function. This toxin activates the Rho GTP-binding protein leading to actin filament reorganization, membrane ruffling and multinucleation. Functionally, CNF1 induces a phagocytic activity in non-professional phagocytes. Surprisingly, we found that the increase of phagocytic activity induced by CNF1 corresponds to a decrease of apoptotic cell death. We therefore hypothesize that the two activities together might have a finalistic role in the pathogenesis of bacterial infection.