Activation of Wnt signaling in the RPE cell line ARPE-19.

<p>(A) Cultured cells were co-transfected with the TOP-FLASH Wnt reporter plasmid and a plasmid containing β-galactosidase, and then incubated with Wnt3a or control conditioned media. Luciferase activity was normalized to β-galactosidase activity. Wnt3a induced a 32-fold increase in luciferase activity compared with control (n = 4, **p = 0.01). (B) Immunodetection of endogenous β-catenin was used to confirm Wnt signaling induction. Cells incubated in control conditioned media have predominantly cytoplasmic and membrane-associated β-catenin (red, arrowheads), indicating low basal levels of Wnt signaling. Stimulation with Wnt3a induced translocation of β-catenin into the nucleus (right, arrows), indicating activation of the Wnt pathway. Scale bar 50 µM.