Figure 5.

Bacterially induced small intestinal epithelial cell apoptosis is blocked by NRG4 in vitro. A: IEC-6 rat ileal epithelial cells were infected with 10⁵ CFU/mL of C. muytjensii (CM), with or without EGF, HRG-1β, or NRG4; after 6 hours, apoptosis was assessed by a luminescent assay for caspase 3 and 7 activity. B: IEC-6 cells were subjected to a drill press wound assay with or without EGF, NRG4, or CM. C: Cells were treated with NRG4 or EGF for 24 hours, and EdU uptake was measured. D: One micromolar Src inhibitor PP2 reversed NRG4 protective effects on IEC-6 cell survival. All experiments included at least four independent repeats. E: Western blot analysis of the ileal mucosal scrapings from 14-day-old mice injected with varying doses of NRG4 for phospho-ErbB4 and phospho-Src. Graphs show means ± SEM. ^∗P < 0.05, ^∗∗P < 0.01, and ^∗∗∗P < 0.001 versus control; ^†P < 0.05 versus CM alone. Rel., relative.