Hypoxia-dependent regulation of nonphagocytic NADPH oxidase subunit NOX4 in the pulmonary vasculature.
Nonphagocytic NADPH oxidases have recently been suggested to play a major role in the regulation of physiological and pathophysiological processes, in particular, hypertrophy, remodeling, and angiogenesis in the systemic circulation. Moreover, NADPH oxidases have been suggested to serve as oxygen sensors in the lung. Chronic hypoxia induces vascular remodeling with medial hypertrophy leading to the development of pulmonary hypertension. We screened lung tissue for the expression of NADPH oxidase subunits. NOX1, NOXA1, NOXO1, p22phox, p47phox, p40phox, p67phox, NOX2, and NOX4 were present in mouse lung tissue. Comparing mice maintained for 21 days under hypoxic (10% O(2)) or normoxic (21% O(2)) conditions, an upregulation exclusively of NOX4 mRNA was observed under hypoxia in homogenized lung tissue, concomitant with increased levels in microdissected pulmonary arterial vessels. In situ hybridization and immunohistological staining for NOX4 in mouse lungs revealed a localization of NOX4 mRNA and protein predominantly in the media of small pulmonary arteries, with increased labeling intensities after chronic exposure to hypoxia. In isolated pulmonary arterial smooth muscle cells (PASMCs), NOX4 was localized primarily to the perinuclear space and its expression levels were increased after exposure to hypoxia. Treatment of PASMCs with siRNA directed against NOX4 decreased NOX4 mRNA levels and reduced PASMC proliferation as well as generation of reactive oxygen species. In lungs from patients with idiopathic pulmonary arterial hypertension (IPAH), expression levels of NOX4, which was localized in the vessel media, were 2.5-fold upregulated. These results support an important role for NOX4 in the vascular remodeling associated with development of pulmonary hypertension.
Mittal
Manish
M
University of Giessen Lung Center, Medical Clinic II/V, Giessen, Germany.
Roth
Markus
M
König
Peter
P
Hofmann
Simone
S
Dony
Eva
E
Goyal
Parag
P
Selbitz
Anne-Christin
AC
Schermuly
Ralph Theo
RT
Ghofrani
Hossein Ardeschir
HA
Kwapiszewska
Grazyna
G
Kummer
Wolfgang
W
Klepetko
Walter
W
Hoda
Mir Ali Reza
MA
Fink
Ludger
L
Hänze
Jörg
J
Seeger
Werner
W
Grimminger
Friedrich
F
Schmidt
Harald H H W
HH
Weissmann
Norbert
N
D000818:Animals; D002455:Cell Division; D002478:Cells, Cultured / Q000187:drug effects / Q000201:enzymology; D002908:Chronic Disease; D015195:Drug Design; D004721:Endoplasmic Reticulum / Q000201:enzymology; D004790:Enzyme Induction; D005260:Female; D006801:Humans; D006976:Hypertension, Pulmonary / Q000188:drug therapy / Q000201:enzymology* / Q000209:etiology / Q000503:physiopathology; D006984:Hypertrophy; D000860:Hypoxia / Q000150:complications / Q000201:enzymology* / Q000503:physiopathology; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000378:metabolism; D008168:Lung / Q000098:blood supply; D008297:Male; D008562:Membrane Glycoproteins / Q000032:analysis; D032389:Myocytes, Smooth Muscle / Q000201:enzymology / Q000473:pathology; D000074662:NADPH Oxidase 2; D000074663:NADPH Oxidase 4; D019255:NADPH Oxidases / Q000032:analysis / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D009569:Nitric Oxide / Q000502:physiology; D009928:Organ Specificity; D010100:Oxygen / Q000378:metabolism / Q000494:pharmacology; D021122:Protein Subunits; D011651:Pulmonary Artery / Q000166:cytology / Q000201:enzymology; D034622:RNA Interference; D012333:RNA, Messenger / Q000096:biosynthesis; D034741:RNA, Small Interfering / Q000494:pharmacology; D013481:Superoxides / Q000378:metabolism; D053773:Transforming Growth Factor beta1 / Q000502:physiology; D017540:Tunica Media / Q000201:enzymology / Q000473:pathology
D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D008562:Membrane Glycoproteins; D021122:Protein Subunits; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D053773:Transforming Growth Factor beta1; D013481:Superoxides; D009569:Nitric Oxide; C056558:CYBB protein, human; C488842:Cybb protein, mouse; D000074662:NADPH Oxidase 2; D000074663:NADPH Oxidase 4; D019255:NADPH Oxidases; C498910:NOX4 protein, human; C422943:Nox4 protein, mouse; D010100:Oxygen