title: Hypoxia-induced acute lung injury in murine models of sickle cell disease.
abstract: Vaso-occlusive events are the major source of morbidity and mortality in sickle cell disease (SCD); however, the pathogenic mechanisms driving these events remain unclear. Using hypoxia to induce pulmonary injury, we investigated mechanisms by which sickle hemoglobin increases susceptibility to lung injury in a murine model of SCD, where mice either exclusively express the human alpha/sickle beta-globin (halphabetaS) transgene (SCD mice) or are heterozygous for the normal murine beta-globin gene and express the halphabetaS transgene (mbeta+/-, halphabetaS+/-; heterozygote SCD mice). Under normoxia, lungs from the SCD mice contained higher levels of xanthine oxidase (XO), nitrotyrosine, and cGMP than controls (C57BL/6 mice). Hypoxia increased XO and nitrotyrosine and decreased cGMP content in the lungs of all mice. After hypoxia, vascular congestion was increased in lungs with a greater content of XO and nitrotyrosine. Under normoxia, the association of heat shock protein 90 (HSP90) with endothelial nitric oxide synthase (eNOS) in lungs of SCD and heterozygote SCD mice was decreased compared with the levels of association in lungs of controls. Hypoxia further decreased association of HSP90 with eNOS in lungs of SCD and heterozygote SCD mice, but not in the control lungs. Pretreatment of rat pulmonary microvascular endothelial cells in vitro with xanthine/XO decreased A-23187-stimulated nitrite + nitrate production and HSP90 interactions with eNOS. These data support the hypotheses that hypoxia increases XO release from ischemic tissues and that the local increase in XO-induced oxidative stress can then inhibit HSP90 interactions with eNOS, decreasing *NO generation and predisposing the lung to vaso-occlusion.
authors.affiliation: Medical College of Wisconsin, Div. of Pediatric Surgery, Cardiovascula Center M4060, 8701 Watertown Plank Rd., Milwaukee, WI 53226, USA. kpritch@mcw.edu
authors.forename: Kirkwood A
authors.initials: KA
authors.lastname: Pritchard
authors.forename: Jingsong
authors.initials: J
authors.lastname: Ou
authors.forename: Zhijun
authors.initials: Z
authors.lastname: Ou
authors.forename: Yang
authors.initials: Y
authors.lastname: Shi
authors.forename: James P
authors.initials: JP
authors.lastname: Franciosi
authors.forename: Paul
authors.initials: P
authors.lastname: Signorino
authors.forename: Sushma
authors.initials: S
authors.lastname: Kaul
authors.forename: Cathleen
authors.initials: C
authors.lastname: Ackland-Berglund
authors.forename: Karin
authors.initials: K
authors.lastname: Witte
authors.forename: Sandra
authors.initials: S
authors.lastname: Holzhauer
authors.forename: Narla
authors.initials: N
authors.lastname: Mohandas
authors.forename: Karen S
authors.initials: KS
authors.lastname: Guice
authors.forename: Keith T
authors.initials: KT
authors.lastname: Oldham
authors.forename: Cheryl A
authors.initials: CA
authors.lastname: Hillery
mesh_terms: D000208:Acute Disease; D000755:Anemia, Sickle Cell / Q000378:metabolism* / Q000473:pathology* / Q000503:physiopathology; D000818:Animals; D004195:Disease Models, Animal; D018841:HSP90 Heat-Shock Proteins / Q000378:metabolism; D006451:Hemoglobin, Sickle / Q000235:genetics; D006801:Humans; D000860:Hypoxia / Q000378:metabolism* / Q000473:pathology* / Q000503:physiopathology; D008171:Lung Diseases / Q000378:metabolism* / Q000473:pathology* / Q000503:physiopathology; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D009569:Nitric Oxide / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; D014443:Tyrosine / Q000031:analogs & derivatives* / Q000378:metabolism
chemical_list: D018841:HSP90 Heat-Shock Proteins; D006451:Hemoglobin, Sickle; D009569:Nitric Oxide; C002744:3-nitrotyrosine; D014443:Tyrosine; C496314:NOS3 protein, human; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; C496315:Nos3 protein, mouse