[Regulation of secretory leukoprotease inhibitor gene expression]

Secretory leukoprotease inhibitor (SLPI), also called antileukoprotease (ALP) or mucous proteinase inhibitor (MPI), is a 12-kDa, nonglycosylated serine protease inhibitor present in mucous secretions. It is thought to play a role in protecting the mucosae from injury associated with inflammation. SLPI is locally produced by serous cells, including bronchial submucosal glands. Previous papers have suggested that its gene expression in the airway epithelial cells shows cell-type specificity and is modulated at the mRNA level under normal and pathological conditions. To characterize the mechanism of this regulation, cis-acting elements which confer transcriptional activity on the SLPI gene were evaluated by luciferase assay, using human epithelial cell lines. Serial deletion of the promoter region from the 5' end showed that different cis-acting elements were responsible for the promoter function in A549 and HeLa cells.