MUCIN MESSENGER-RNA EXPRESSION IN NORMAL AND VASOMOTOR INFERIOR TURBINATES

Mucins are the major glycoprotein component of respiratory tract secre tions. Little is known about their expression in the upper respiratory tract. In order to define this expression, in situ hybridization was performed on 19 normal and 4 vasomotor rhinitis (VMR) inferior turbina tes to identify mucin mRNA. MUC1, MUC2, MUC4, MUC5AC, MUC5B, and MUC7 were expressed in both the normal and VMR turbinates. MUC4 and MUC5AC were the most highly expressed mucins. MUC1, MUC2, MUC4, and MUC5AC we re expressed mainly by the epithelial border, whereas MUC5B and MUC7 w ere expressed by the submucosal glands. MUC1 and MUC4 exhibited a diff use expression by multiple cell types along the mucosal border, wherea s MUC2 and MUC5AC expression appeared to be limited to a subpopulation of epithelial cells, most likely goblet cells. Although MUC1, MUC4, a nd MUC5AC showed sporadic submucosal glandular expression, MUC5B and M UC7 appeared to be the predominant submucosal gland mucins in the infe rior turbinates. MUC3 and MUC6 expression, which have been found prima rily in the gastric mucosa, were not seen in any of the inferior turbi nate samples examined. The only difference seen between normal and VMR turbinates was a slight decrease in MUC1 expression in the VMR group. The variety of mucins expressed and the diversity of their expression patterns may have significance in terms of the theologic and particle clearance properties of nasal secretions. Understanding the expressio n patterns in normal turbinates will serve as the foundation for furth er study of these mucins in disease states.