title: Sepiapterin improves angiogenesis of pulmonary artery endothelial cells with in utero pulmonary hypertension by recoupling endothelial nitric oxide synthase.
abstract: Persistent pulmonary hypertension of the newborn (PPHN) is associated with decreased blood vessel density that contributes to increased pulmonary vascular resistance. Previous studies showed that uncoupled endothelial nitric oxide (NO) synthase (eNOS) activity and increased NADPH oxidase activity resulted in marked decreases in NO bioavailability and impaired angiogenesis in PPHN. In the present study, we hypothesize that loss of tetrahydrobiopterin (BH4), a critical cofactor for eNOS, induces uncoupled eNOS activity and impairs angiogenesis in PPHN. Pulmonary artery endothelial cells (PAEC) isolated from fetal lambs with PPHN (HTFL-PAEC) or control lambs (NFL-PAEC) were used to investigate the cellular mechanisms impairing angiogenesis in PPHN. Cellular mechanisms were examined with respect to BH4 levels, GTP-cyclohydrolase-1 (GCH-1) expression, eNOS dimer formation, and eNOS-heat shock protein 90 (hsp90) interactions under basal conditions and after sepiapterin (Sep) supplementation. Cellular levels of BH4, GCH-1 expression, and eNOS dimer formation were decreased in HTFL-PAEC compared with NFL-PAEC. Sep supplementation decreased apoptosis and increased in vitro angiogenesis in HTFL-PAEC and ex vivo pulmonary artery sprouting angiogenesis. Sep also increased cellular BH4 content, NO production, eNOS dimer formation, and eNOS-hsp90 association and decreased the superoxide formation in HTFL-PAEC. These data demonstrate that Sep improves NO production and angiogenic potential of HTFL-PAEC by recoupling eNOS activity. Increasing BH4 levels via Sep supplementation may be an important therapy for improving eNOS function and restoring angiogenesis in PPHN.
authors.affiliation: Division of Neonatology, Dept. of Pediatrics, Medical College of Wisconsin, Suite C410, Children Corporate Center, 999N 92nd St., Wauwatosa, WI 53226, USA. rteng@mcw.edu
authors.forename: Ru-Jeng
authors.initials: RJ
authors.lastname: Teng
authors.forename: Jianhai
authors.initials: J
authors.lastname: Du
authors.forename: Hao
authors.initials: H
authors.lastname: Xu
authors.forename: Ivane
authors.initials: I
authors.lastname: Bakhutashvili
authors.forename: Annie
authors.initials: A
authors.lastname: Eis
authors.forename: Yang
authors.initials: Y
authors.lastname: Shi
authors.forename: Kirkwood A
authors.initials: KA
authors.lastname: Pritchard
authors.forename: Girija G
authors.initials: GG
authors.lastname: Konduri
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D001708:Biopterins / Q000031:analogs & derivatives / Q000378:metabolism; D002465:Cell Movement / Q000187:drug effects; D004730:Endothelium, Vascular / Q000378:metabolism; D006136:GTP Cyclohydrolase / Q000096:biosynthesis; D018841:HSP90 Heat-Shock Proteins / Q000378:metabolism; D006801:Humans; D007231:Infant, Newborn; D018919:Neovascularization, Physiologic / Q000187:drug effects; D052250:Nitric Oxide Synthase Type III / Q000187:drug effects / Q000378:metabolism*; D010547:Persistent Fetal Circulation Syndrome; D055503:Protein Multimerization / Q000187:drug effects; D011622:Pterins / Q000494:pharmacology*; D034561:Sheep, Domestic
chemical_list: D018841:HSP90 Heat-Shock Proteins; D011622:Pterins; D001708:Biopterins; C016727:sepiapterin; D052250:Nitric Oxide Synthase Type III; D006136:GTP Cyclohydrolase; C003402:sapropterin