Figure 4. SFK activate YAP downstream to gp130^Act and are active in human IBD.

(a) IHC of activating (Y419) and inhibitory (Y530) Src phosphorylation in paraffin-embedded small intestinal sections from WT and Tg mice. (b) WT and Tg small intestinal organoids were lysed and analyzed for expression and phosphorylation of the indicated proteins. (c) Tg mice (n=4/group) were treated with PP2 (5 mg/kg) or vehicle once a day for 5 days. Small intestinal sections were stained as indicated. Positive cells were enumerated in each villus or crypt. Data are averages ± SD. *P < 0.05. (d) Normal (n=11) and CD (n=18) human colon biopsies were fixed, sectioned and stained as indicated. Src and YAP activation were found in 11/18 CD specimens in areas with active disease. (e) Co-immunoprecipitation (IP) of endogenous gp130, SFK and YAP in HT29 cells. Cells were collected with or without 2 hr IL-6 (10 ng/ml) stimulation. Lysates were IP’ed with gp130 (left) or Src (right) antibodies or corresponding IgG controls and probed with the indicated antibodies. (f) Total cell lysates of T84 colon cancer cells transfected with empty vector (EV), gp130^Act, gp130^Act(Δ771-811) or gp130^Act(Δ812-827) expression vectors were prepared and subjected to IB analysis with the indicated antibodies. (g) WT and Tg small intestinal organoids were treated with DMSO and PP2 (10 μM) for 24 hrs, stained with YAP antibody and counter stained with DAPI. Scale bars represent 100 μm (a, c, d, g) and all data are representative of at least 2–3 independent experiments.