Figure 6.

Curcumin blocks the cytotoxic effect induced by EPEC in HEp-2 cells by inhibiting EspC internalization without affecting the formation of pedestals and its adherence pattern on epithelial cells. Confocal microscopy of HEp-2 cells infected with EPEC (MOI 10) during 2 h (A) and a magnified view of bacteria-only (B) in presence or absence of Curcumin (16 μg/mL). Uninfected cells were used as control. After treatment, cells were processed for confocal microscopy as indicated in Figure 5, but EspC secretion and internalization was detected by immunofluorescence using an anti-EspC passenger domain antibody followed by biotin-SP-conjugated goat anti-rabbit IgG and DTAF-conjugated streptavidin. Arrow indicates the localized adherence of EPEC on HEp-2 cells. Arrowheads indicates the formation of actin pedestals, while thin arrows indicate the cell rounding effect. An asterisk denotes the absence of internalized EspC in HEp-2 cells; scale bar 15 μm in (A). Scale bar 5 μm in (B).