A potential role for reactive oxygen species and the HIF-1alpha-VEGF pathway in hypoxia-induced pulmonary vascular leak.
Acute hypoxia causes pulmonary vascular leak and is involved in the pathogenesis of pulmonary edema associated with inflammation, acute altitude exposure, and other critical illnesses. Reactive oxygen species, HIF-1, and VEGF have all been implicated in various hypoxic pathologies, yet the ROS-HIF-1-VEGF pathway in pulmonary vascular leak has not been defined. We hypothesized that the ROS-HIF-1-VEGF pathway has an important role in producing hypoxia-induced pulmonary vascular leak. Human pulmonary artery endothelial cell (HPAEC) monolayers were exposed to either normoxia (21% O(2)) or acute hypoxia (3% O(2)) for 24 h and monolayer permeability and H(2)O(2), nuclear HIF-1alpha, and cytosolic VEGF levels were determined. HPAEC were treated with antioxidant cocktail (AO; ascorbate, glutathione, and alpha-tocopherol), HIF-1 siRNA, or the VEGF soluble binding protein fms-like tyrosine kinase-1 (sFlt-1) to delineate the role of the ROS-HIF-1-VEGF pathway in hypoxia-induced HPAEC leak. Additionally, mice exposed to hypobaric hypoxia (18,000 ft, 10% O(2)) were treated with the same antioxidant to determine if in vitro responses corresponded to in vivo hypoxia stress. Hypoxia increased albumin permeativity, H(2)O(2) production, and nuclear HIF-1alpha and cytosolic VEGF concentration. Treatment with an AO lowered the hypoxia-induced HPAEC monolayer permeability as well as the elevation of HIF-1alpha and VEGF. Treatment of hypoxia-induced HPAEC with either an siRNA designed against HIF-1alpha or the VEGF antagonist sFlt-1 decreased monolayer permeability. Mice treated with AO and exposed to hypobaric hypoxia (18,000 ft, 10% O(2)) had less pulmonary vascular leak than those that were untreated. Our data suggest that hypoxia-induced permeability is due, in part, to the ROS-HIF-1alpha-VEGF pathway.
Irwin
David C
DC
University of Colorado Health Science Center, School of Medicine, Denver, CO 80262, USA. David.Irwin@ucdenver.edu
McCord
Joe M
JM
Nozik-Grayck
Eva
E
Beckly
Ginny
G
Foreman
Ben
B
Sullivan
Tim
T
White
Molly
M
T Crossno
Joseph
J
Bailey
Damian
D
Flores
Sonia C
SC
Majka
Susan
S
Klemm
Dwight
D
van Patot
Martha C Tissot
MC
D021581:Active Transport, Cell Nucleus / Q000187:drug effects / Q000235:genetics; D000818:Animals; D000975:Antioxidants / Q000494:pharmacology; D002199:Capillary Permeability / Q000187:drug effects / Q000235:genetics; D002467:Cell Nucleus / Q000378:metabolism*; D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000378:metabolism* / Q000473:pathology; D000860:Hypoxia; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D011651:Pulmonary Artery / Q000473:pathology; D034741:RNA, Small Interfering / Q000235:genetics; D017382:Reactive Oxygen Species / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics; D015533:Transcriptional Activation / Q000187:drug effects / Q000235:genetics; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism*
D000975:Antioxidants; C497443:Hif1a protein, mouse; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D034741:RNA, Small Interfering; D017382:Reactive Oxygen Species; D042461:Vascular Endothelial Growth Factor A; C467480:vascular endothelial growth factor A, mouse