Developmental regulation of DUOX1 expression and function in human fetal lung epithelial cells.
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 Omega.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 ( approximately 21-fold), its maturation factor DUOXA1 ( approximately 12-fold), as well as DUOX protein ( approximately 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.
Fischer
Horst
H
Children's Hospital Oakland Research Institute, 5700 Martin Luther King Jr. Way, Oakland, CA 94609-1673, USA. hfischer@chori.org
Gonzales
Linda K
LK
Kolla
Venkatadri
V
Schwarzer
Christian
C
Miot
Françoise
F
Illek
Beate
B
Ballard
Philip L
PL
D000143:Acids / Q000378:metabolism; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D003907:Dexamethasone / Q000494:pharmacology; D000074623:Dual Oxidases; D005333:Fetus / Q000166:cytology; D005420:Flavoproteins / Q000235:genetics* / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D005938:Glucocorticoids / Q000494:pharmacology; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism; D019255:NADPH Oxidases / Q000235:genetics* / Q000378:metabolism; D010641:Phenotype; D011650:Pulmonary Alveoli / Q000166:cytology / Q000196:embryology / Q000502:physiology; D012333:RNA, Messenger / Q000378:metabolism; D020545:Respiratory Mucosa / Q000166:cytology / Q000196:embryology* / Q000502:physiology*; D015854:Up-Regulation / Q000187:drug effects / Q000502:physiology
D000143:Acids; D005420:Flavoproteins; D005938:Glucocorticoids; D012333:RNA, Messenger; D003907:Dexamethasone; D006861:Hydrogen Peroxide; D000074623:Dual Oxidases; D019255:NADPH Oxidases; C431513:DUOX1 protein, human