Figure 5.

Helicobacter pylori-induced suppression of claudin-7 is mediated by snail. MKN28 cells were cocultured with H. pylori strain 60 190 and levels of snail mRNA (A), and snail total protein (B and C) were quantified. (A) Real-time RT-PCR was performed on isolated RNA and quantified. (B) Representative western blot for snail and glyceraldehyde 3-phosphate dehydrogenase (GAPDH) in MKN28 cells in the presence or absence of H. pylori. (C) Densitometric analysis demonstrating increased expression of snail in H. pylori-infected cells. (D) Immunofluorescence for snail (green) in uninfected MKN28 cells or MKN28 cells infected with H. pylori strain 7.13. Nuclei are labelled with Hoechst (blue). (E and F) Control non-targeting (NT) siRNA or siRNA targeting snail was transfected in MKN28 cells followed by infection with or without H. pylori. Levels of claudin-7 expression were then determined by western blotting. (E) Representative western blot for claudin-7 and GAPDH in MKN28 cells in the presence or absence of non-targeting or snail-specific siRNA. (F) Densitometric analysis demonstrating that decreased expression of claudin-7 in H. pylori-infected cells is abolished in the presence of snail-specific siRNA, n=3 independent replicates.