Changes in cell adhesion properties are associated with the formation of fluid-filled spaces in an epithelium.

The sensory epithelium of the cochlea, the organ of Corti, has complex cytoarchitecture consisting of mechanosensory hair cells intercalated by support cells. The support cells provide important trophic and structural support to the hair cells and must be stiff yet compliant enough to modulate vibrations to the organ of Corti. Once the sensory cells are properly arranged, the support cells undergo significant remodeling to help the sensory epithelium transition from a simple epithelium into a structurally rigid epithelium with fluid-filled spaces. Cadherins are cell adhesion molecules that are necessary for sorting and connecting cells in an intact epithelium. To create the fluid-filled spaces, the cell adhesion properties of adjoining cell membranes between cells must change to allow the formation of spaces within an epithelium. However, the dynamic localization of cadherins has not been properly analyzed as these spaces are formed. There are three cadherins that are reported to be expressed during the first postnatal week of development when the tunnel of Corti forms in the cochlea. We characterized the dynamic localization of cadherins that are associated with the cytoskeletal remodeling at the contacting membranes of the inner and outer pillar cells flanking the tunnel of Corti.