Figure 6

Geniposide triggered ductal epithelial cell to β-cell conversion through upregulating TCF7L2 and activating JAK2/STAT3 pathway. TCF7L2 expression in islets β-cells (a) and in the ductal epithelium cells (b) were examined by triple staining of mice pancreatic sections for TCF7L2 in red, insulin, or CK19 in green, and DAPI in blue. Values are representative of three to four slides spanning the whole pancreas of each mouse and six mice per group. Data are shown as mean±S.E. (^#P<0.01 vehicle to WT or ND group; *P<0.01 geniposide to vehicle group). (c) Isolated mouse exocrine cells were cultured with 20 μM geniposide for 4 days, then embedded in paraffin and sections were analyzed by immunostaining of CK19, insulin, PDX-1, MafA, and Glut2 to confirm the effect of geniposide on ductal cell differentiation. (d) Isolated mouse exocrine cells were cultured with different treatments (20 μM geniposide, 20 mM AG490, and 25 μM ICG001) for 4 days. Upregulation of TCF7L2 and activation of JAK2/STAT3 were analyzed by western blot analysis. Data are shown from three independent experiments. (e) Effects of AG490 and ICG001 on the differentiation of ductal epithelial cells. The cells were examined by insulin (red, indicated by white arrows) and CK19 (green), and DAPI (blue) triple staining. (f) RT-PCR analyses of Pdx-1, insulin, and TCF7L2 expressions in treated ductal epithelial cells. The experiments were performed in triplicate. The levels of gene expressions were normalized to tubulin (^#P<0.01, geniposide to DMSO-treated group; *P<0.01, geniposide to AG490- or ICG001-treated group). Scale bars, 20 μm