FIG. 5.

OSM overexpression in tubular epithelial cells induces TEC-myofibroblast transdifferentiation. (A) Control GFP-transfected cells display typical epithelial morphology, including cuboidal cells forming regular monolayers. In contrast, (B) OSM-transfected cells show focal areas with mesynchymal features (center) including cells with spindled morphology forming layers, indicating a loss of contact inhibition (magnification of ×200). (C) Immunofluorescent staining shows a marked expression of E-cadherin (red), an epithelial marker, in control GFP-transfected cells (green demonstrates GFP transfection efficiency in GFP-expressing NRK52E cells), but E-cadherin staining is very low in OSM-transfected cells (D) (magnification of ×400). (E) Western blot analyses demonstrate that overexpression of OSM in NRK52E cells (lane 2) induces de novo expression of α-SMA, and a loss of E-cadherin compared to GFP-transfected cells (lane 1). (F) Real-time recordings of the electrical impedance as an indicator of cell adhesion. Rate of epithelial cell adhesion on microelectrode surface is decreased in OSM-expressing cells as compared to control GFP-transfected cells. All tracings are representative of three experiments.