Osteopontin Expression in Polarized MDCK Cells

The aim of this study is to indicate expression of osteopontin (OPN) in Madin-Darby Canine Kidney (MDCK) cells with different confluences (10, 50, 90, 100%). OPN expression were investigated by western blotting. An increase in OPN expression was observed due to the increased confluency and subsequent initiation of polarization. Expression profiles of flotillin-2 in the same cells were used as a control, since this protein is ubiquitously produced in MDCK cells and its expression rates are independent of confluence and / or polarization. Intracellular distribution of OPN was also monitored by confocal microscopy on preparations immunolabeled with anti-OPN antibodies. Staining patterns have also confirmed increased OPN expression, especially mannose rich isoforms showed an increase dependent on confluency and polarization in MDCK cells. The results were concluded that increased OPN expression during confluency and polarization in MDCK cells. The state of confluence and polarization have significant effects on the mannose rich OPN expression profile.