Altered mucin gene expression in hypertrophic human nasal mucosa

Abstract

A function of nasal turbinates is the removal of particles bythe action of the cilia moving a mucous blanket. The rheologicalproperties of the mucous secretion are critical to this functionand dependent on several factors, in particular the integrity and type of mucin present. Recent work has shown that MUC5AC is a major secreted mucin in the respiratory tract and MUC2 is expressed at a much lower level.1,2 Alteration in the levels of expression of mucin genes could potentially alter the transport and lubricating properties of mucous. mRNA was isolated from inferior nasal turbinates and electrophoresis showed a polydisperse mRNA population. Northern blots were probed with 48bp digoxigenin labelled antisense oligonucleotides to the tandem repeat sequences of MUC2 and MUC5AC. The MUC2 probe gave an intense signal with the positive control (human ileum), in contrast the negative control (rat kidney) showed no binding. Turbinate mRNA also gave a strong signal although not as intense as ileum. The MUC5AC probe bound to turbinate mRNA and ileum although to a lesser extent than MUC2. The results show that both MUC2 and MUC5AC are expressed in human nasal turbinates and interestingly the level ofMUC2 was higher than that of MUC5AC (using these probes). This reversal in mucin secretory pattern, presumablya function of hyperplasia could lead to altered mucous properties. This tissue may provide a good model to study diseases in tissues of the same embryological origin and similar histology where cell proliferative changes occur, i.e. diseases of middle ear mucosa. We thank the Hearing Research Trust for their support.