Regulation of Mucin and Non-Mucin Secretions and Gene Expression by Triiodothyronine and Collagen Gel in Human Airway Epithelium / 대한이비인후과학회지

ABSTRACT

BACKGROUND AND OBJECTS We have been interested in elucidating the role of hormones and growth factors in regulating differentiation and mucin and non-mucin secretions. Our purpose is to investigate the effects of each supplement contained in the culture medium for mucin and non-mucin secretions. MATERIALS AND METHODS: Individual factors were removed from the culture media of normal human tracheobronchial epithelial (NHTBE) cells grown in air-liquid interface cultures. The effects on the cell phenotype, mucin, lysozyme (LZ), and secretory leukocyte protease inhibitor (SLPI) secretion and gene expression were examined. RESULTS: Deletion of hydrocortisone, epinephrine, transferrin or amphotericin-gentamycin from the media had no reproducible effects; Deletion of insulin was incompatible with culture growth. Removal of triiodothyronine selectively increased mucin secretion, but did not affect the gene expression. However, MUC5AC mRNA levels were reproducibly increased, suggesting that the expressions of these two mucin genes were differentially regulated. LZ and SLPI secretion levels were not significantly affected by the deletion of triiodothyronine from the culture media. The LZ mRNA levels were increased in the absence of triiodothyronine whereas the SLPI transcript levels were not affected. Omission of the attachment substratum and the type 1 collagen gel resulted in a significant increase in all 3 secretory products. MUC2 and MUC5AC steady state mRNA levels were not consistently affected. In contrast, LZ and SLPI gene expressions were reproducibly increased. CONCLUSION: This study shows that individual factors in the epithelial environment can regulate the expression of specific secretory cell gene products in a highly selective manner.