title: Cystic fibrosis transmembrane conductance regulator-dependent regulation of epithelial inducible nitric oxide synthase expression.
abstract: Recent evidence has shown that the inducible form of nitric oxide (NO) synthase (NOS2) has reduced expression in airway epithelia of patients with cystic fibrosis (CF) despite the presence of chronic inflammation. The goal of this paper is to determine whether NOS2 expression is regulated by the presence of functional CF transmembrane conductance regulator (CFTR). Using a human trachea epithelial cell line in which CFTR activity is blocked by the overexpression of the CFTR regulatory domain, we found that loss of CFTR activity reduces NOS2 messenger RNA expression as determined by reverse transcriptase/polymerase chain reaction and reduces overall NO production compared with mock-transfected controls. An in vivo model using mice lacking CFTR expression (cftr -/-), wild-type mice (cftr +/+), and cftr -/- mice that have had human CFTR introduced to the intestinal epithelium using the fatty acid binding protein (FABP) promoter (FABP-hcftr) was also examined. Electrical characterization confirmed that FABP-hcftr mice had corrected electrophysiologic properties compared with cftr -/- mice in the ileum, but FABP-hcftr nasal transepithelial potential difference measurements were identical to cftr -/- values showing specific intestinal correction. NOS2-specific immunostaining revealed that NOS2 expression is evident in sections of ileum and nasal epithelium of cftr +/+ mice but is absent in both tissues in cftr -/- mice. FABP-hcftr mice, however, show strong NOS2 staining in epithelial cells of the ileum but reduced staining in the nasal epithelium, suggesting a CFTR-related influence in the regulation of NOS2 expression in epithelial cells.
authors.affiliation: Departments of Pediatrics and Genetics, and Center for Human Genetics, Case Western Reserve University, Cleveland, Ohio 44106-4948, USA.
authors.forename: W K
authors.initials: WK
authors.lastname: Steagall
authors.forename: H L
authors.initials: HL
authors.lastname: Elmer
authors.forename: K G
authors.initials: KG
authors.lastname: Brady
authors.forename: T J
authors.initials: TJ
authors.lastname: Kelley
mesh_terms: D000818:Animals; D002352:Carrier Proteins / Q000235:genetics; D002460:Cell Line; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D004847:Epithelial Cells / Q000201:enzymology*; D000071438:Fatty Acid-Binding Protein 7; D050556:Fatty Acid-Binding Proteins; D006801:Humans; D007082:Ileum / Q000201:enzymology; D007150:Immunohistochemistry; D008564:Membrane Potentials / Q000235:genetics; D051379:Mice; D018345:Mice, Knockout; D018996:Myelin P2 Protein / Q000235:genetics; D009297:Nasal Mucosa / Q000502:physiology; D009363:Neoplasm Proteins; D009419:Nerve Tissue Proteins; D019001:Nitric Oxide Synthase / Q000096:biosynthesis* / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II; D011401:Promoter Regions, Genetic; D017434:Protein Structure, Tertiary / Q000235:genetics; D013194:Staining and Labeling; D025521:Tumor Suppressor Proteins
chemical_list: C505032:CFTR protein, human; D002352:Carrier Proteins; C107608:FABP7 protein, human; C082667:Fabp5 protein, mouse; C086936:Fabp7 protein, mouse; D000071438:Fatty Acid-Binding Protein 7; D050556:Fatty Acid-Binding Proteins; D018996:Myelin P2 Protein; D009363:Neoplasm Proteins; D009419:Nerve Tissue Proteins; D025521:Tumor Suppressor Proteins; D019005:Cystic Fibrosis Transmembrane Conductance Regulator; C496319:NOS2 protein, human; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496317:Nos2 protein, mouse