Figure 12.

Autophagy enhances occludin levels in human colonic tissues in an ERK1/2-dependent mechanism. [A] Western blot for occludin from rapamycin- [300 nM] treated normal [NT] and Crohn’s disease [CD] colonic mucosal tissue. [B] Quantification of occludin levels in panel A. [C] Confocal immunofluorescence for occludin [green], apical F-actin [red] and nuclei [blue] in normal human colonoids after 18 h of the indicated treatments. White scale bar = 10 µm. [D] Quantification of occludin fluorescence from panel C. Data are representative of three or more independent experiments with multiple fields captured in each. [E] Occludin levels from normal human mucosa upon rapamycin treatment with or without the ERK1/2 inhibitor U0126 [25 µM]. Inhibition of ERK1/2 prevented the rapamycin-induced upregulation of occludin levels. [F] Quantification of occludin levels in panel E. n = 6 per group. [G] Rapamycin-induced reduction in human colonic inulin flux was prevented upon inhibition of ERK1/2 with U0126 or PD98059. n = 6 per group. One-way ANOVA with Tukey’s post-hoc test. *, p < 0.05; **, p < 0.01; ****, p < 0.0001; ns, non-significant.