DESCRIPTION: (Adapted from the applicant's abstract and Specific Aims.) Cystic Fibrosis (CF) is the most common fatal inherited disease in Caucasians. A characteristic pathologic feature is the blockage of exocrine glands in mucus-rich respiratory, gastrointestinal and reproductive tracts which is the basis for the generally held assumption that CF mucus is abnormal. Although the CF gene and gene product, the Cystic Fibrosis transmembrane conductance regulatory (CFTR) have been identified, their relationship to the mucus abnormality is not defined. Since mucin glycoproteins (mucins) are the major macromolecular components of mucus and are responsible for its viscoelastic properties in vivo, alterations in mucins may effect the physiologic behavior of mucus. There are at least four human mucin protein genes expressed in respiratory epithelium; the relative expression of these genes is not known in CF or non-CF epithelium. This application proposes to determine the relative expression of mucin genes in CF and normal epithelium. The long term objective is to elucidate the role of airway mucins in health and disease. The Specific Aims of the present application are: 1) to measure levels of mucin mRNA transcripts in freshly obtained CF and normal nasal epithelial cells and immortalized CF cell lines and matched CF cell lines which have been transfected with the wild-type CFTR gene using a newly developed quantitative mucin RNA method; 2) to test inflammatory mediators known to affect secretion of high molecular weight glycoproteins and known to be present in CF airways to identify agents which modulate expression of specific mucin genes at the transcriptional level in epithelial cells; and 3) to quantitate levels of secreted and cellular mucin proteins in a cell line under resting or stimulated conditions using enzyme linked immunosorbent assays (ELISAs) with specific anti-mucin-peptide antibodies to elucidate whether mucin production is regulated at the transcriptional, translational and/or secretory levels. The information derived from the proposed experiments may fill a major gap in understanding the mucus/mucin abnormality in CF as well as provide basic information about mucin expression in respiratory epithelium.