FIGURE 4.

Jak3 promotes expression of enterocytic differentiation markers in human IEC. A, left panel, human-derived colonic epithelial cells HT-29 Cl-19A were grown until subconfluence (Sub), confluence (Conf), and 2 and 4 weeks (wks) postconfluence. Cells lysates were analyzed by IB for the indicated proteins using β-actin as control. Representative blots (n = 3) are shown. Right panel, similar experiments were performed as under the left panel except using HT-29 Cl-19a cells that were stably transfected with wild type HA-tagged Jak3. B, Jak3 expression promotes TEER. Control, HA-tagged Jak3-expressing (Jak3-HT-29) and doxycycline-regulated RFP-tagged Jak3-shRNA (shRNA-HT-29) expressing in Jak3-HT-29 cells were cultured in a 24-transwell plate to confluence, and TEER was measured. Mean values (n = 6 independent experiments) of TEER are shown. For Jak3 shRNA-HT-29, the expression of RFP-tagged Jak3-shRNA was induced by supplementing doxycycline in the growth media. Previously, we reported that this leads to knock down of Jak3 expression in HT-29 CL-19A cells where treatment with doxycyline alone in untransduced cells had no effect on Jak3 expression (25). C and D, Jak3 KO mice show symptoms of PLE. Serum total protein and albumin (C) and fecal α1-antitrypsin (D) were determined in serum and fecal extracts, respectively, from WT and KO mice using methods described under “Experimental Procedures.” Lower panel in C and D show representative images (n = 3). B–D, values are means ± S.E. (n = 6). Asterisks indicate statistically significant differences (p < 0.05) from the control cells.