Figure 6
Experimental infection of HT-29/B6-GR/MR cell monolayers. (a) Electrogenic sodium transport (JNa) in untreated control monolayers, C. jejuni-infected or cytokine cocktail-treated epithelial cell monolayers, or co-treatment. To induce ENaC activity, cells were pre-stimulated for 5 days with 5 × 10−8M dexamethasone, 2 × 10−3 M sodium-butyrate, 3 × 10−9M aldosterone as described before.19 C. jejuni infection dose; multiplicity of infection (MOI) 100, infection duration; 48 h, addition of low-dose cytokine cocktail, consisting of recombinant human interferon-γ (10 U ml−1), tumor necrosis factor-α (10 U ml−1), interleukin-13 (10 ng ml−1), and interleukin-1β (10 ng ml−1), cytokine incubation; 24 h. ISC was measured in Ussing chambers before and after ENaC inhibition with amiloride (10−4M), which was added to the mucosal compartment. The drop in ISC was attributed to the ENaC-dependent Na+ flux (JNa). n=6 cell monolayers each group. (b) Transepithelial electrical resistance (Ω cm2) of the respective cell monolayers and conditions above, measured at the same incubation endpoints and after addition of amiloride. n=12. *P<0.05, **P<0.01, ***P<0.001, Student’s t-test with Holm–Bonferroni adjustment for multiple comparisons. Data represent mean±s.e.m.
