Developmental regulation of DUOX1 expression and function in human fetal lung epithelial cells

• Published in: American journal of physiology. Lung cellular and molecular physiology 2007-06, Vol.292 (6), p.L1506-L1514
• Main Authors: Fischer, Horst, Gonzales, Linda K, Kolla, Venkatadri, Schwarzer, Christian, Miot, Francoise, Illek, Beate, Ballard, Philip L
• Format: Article
• Language: English
• Subjects: Acids - metabolism; Cell culture; Cell Differentiation - drug effects; Cell Differentiation - physiology; Cells, Cultured; Dexamethasone - pharmacology; Dual Oxidases; Fetus - cytology; Flavoproteins - genetics; Flavoproteins - metabolism; Gene expression; Gene Expression Regulation, Developmental; Genotype & phenotype; Glucocorticoids - pharmacology; Humans; Hydrogen Peroxide - metabolism; Lungs; NADPH Oxidases - genetics; NADPH Oxidases - metabolism; Phenotype; Proteins; Pulmonary Alveoli - cytology; Pulmonary Alveoli - embryology; Pulmonary Alveoli - physiology; Respiratory Mucosa - cytology; Respiratory Mucosa - embryology; Respiratory Mucosa - physiology; RNA, Messenger - metabolism; Studies; Up-Regulation - drug effects; Up-Regulation - physiology
• ISSN: 1040-0605; 1522-1504
• DOI: 10.1152/ajplung.00029.2007

1 Children's Hospital Oakland Research Institute, Oakland, California; 2 Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, Pennsylvania; 3 Faculté de Médecine, Université Libre de Bruxelles, Bruxelles, Belgium; and 4 Laurel Heights Campus, University of California San Francisco, San Francisco, California Submitted 19 January 2007 ; accepted in final form 27 February 2007 The purpose of this study was to determine the expression and cellular functions of the epithelial NADPH oxidase DUOX1 during alveolar type II cell development. When human fetal lung cells (gestational age 11–22 wk) were cultured to confluency on permeable filters, exposure of cells to a hormone mixture (dexamethasone, 8-Br-cAMP, and IBMX, together referred to as DCI) resulted in differentiation of cells into a mature type II phenotype as assessed by expression of lamellar bodies, surfactant proteins, and transepithelial electrical parameters. After 6 days in culture in presence of DCI, transepithelial resistance (2,616 ± 529 ·cm 2 ) and potential (–8.5 ± 0.6 mV) indicated epithelial polarization. At the same time, treatment with DCI significantly increased the mRNA expression of DUOX1 ( 21-fold), its maturation factor DUOXA1 ( 12-fold), as well as DUOX protein ( 12-fold), which was localized near the apical cell pole in confluent cultures. For comparison, in fetal lung specimens, DUOX protein was not detectable at up to 27 wk of gestational age but was strongly upregulated after 32 wk. Function of DUOX1 was assessed by measuring H 2 O 2 and acid production. Rates of H 2 O 2 production were increased by DCI treatment and blocked by small interfering RNA directed against DUOX1 or by diphenylene iodonium. DCI-treated cultures also showed increased intracellular acid production and acid release into the mucosal medium, and acid production was largely blocked by knockdown of DUOX1 mRNA. These data establish the regulated expression of DUOX1 during alveolar maturation, and indicate DUOX1 in alveolar H 2 O 2 and acid secretion by differentiated type II cells. nicotinamide adenine dinucleotide phosphate oxidase; alveolar type II cells; hydrogen peroxide; intracellular pH Address for reprint requests and other correspondence: H. Fischer, Children's Hospital Oakland Research Institute, 5700 Martin Luther King Jr. Way, Oakland, CA 94609-1673 (e-mail: hfischer{at}chori.org )