Polarity of Mature Human Odontoblasts

Odontoblast polarization is based on histological appearance as columnar cells with asymmetric disposition of organelles and plasma membrane domains. However, little is known about the odontoblast plasma membrane organization. We investigated odontoblast membrane polarity using influenza virus hemagglutinin and vesicular stomatitis virus glycoprotein as model proteins in mature human odontoblast organ culture. We also examined the distribution patterns of aquaporin 4 and 5, which are basolateral and apical proteins in epithelial cells, respectively. Confocal microscopy immunofluorescence and electron microscopy demonstrated that the apical markers located at the surface toward pulp and basolateral markers located at the plasma membrane of odontoblast processes. Therefore, odontoblast plasma membrane polarity was different from that in epithelial cells. Also, certain lectins stained odontoblast processes while others stained the soma, reflecting the different natures of their membrane domains. Strong ZO-1 and weaker claudin expression suggest weak tight junctions in the odontoblasts. TGF-β1 showed a tendency to reinstate the expression of selected TJ genes, indicating that TGF-β1 may control odontoblast cell layer integrity by controlling tight junction protein expression.