title: AMP kinase activation improves angiogenesis in pulmonary artery endothelial cells with in utero pulmonary hypertension.
abstract: Pulmonary artery endothelial cells (PAEC) isolated from fetal lambs with in utero pulmonary hypertension (IPH) have phenotypical changes that lead to increased reactive oxygen species (ROS) formation and impaired angiogenesis. AMP-activated protein kinase (AMPK) is known to be activated by ROS, which is expected to help angiogenesis in IPH-PAEC. The objectives of this study were to investigate AMPK responses in IPH and its role in angiogenesis. We observed that, compared with control PAEC, IPH-PAEC have decreased phosphorylation of AMPKα catalytic subunit and AMPK downstream enzymes, indicating a decrease in AMPK activity. In addition, the expression of AMPK kinases is decreased, and protein phosphatase 2 is increased in IPH-PAEC, potentially contributing to the decreased AMPK activation. Metformin, an AMPK activator, improved IPH-PAEC angiogenesis while increasing endothelial NO synthase (eNOS) serine(1179) phosphorylation and decreasing the eNOS-caveolin-1 association. Metformin also increased MnSOD activity and the expression of both eNOS and MnSOD. The increase in angiogenesis by Metformin is abolished by pretreatment with AMPK inhibitor, Compound C. Expression of vascular endothelial growth factor (VEGF) and platelet-derived growth factor β (PDGFβ) are decreased in IPH-PAEC compared with control PAEC and were not altered by Metformin. These data indicate that Metformin improves angiogenesis through mechanisms independent of these angiogenic factors. In conclusion, activation of AMPK restores angiogenesis and increases the bioavailability of nitric oxide in IPH. Whether Metformin is beneficial in the management of pulmonary hypertension requires further investigation.
authors.affiliation: Department of Pediatrics, Medical College of Wisconsin, Milwaukee, 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: Adeleye J
authors.initials: AJ
authors.lastname: Afolayan
authors.forename: Annie
authors.initials: A
authors.lastname: Eis
authors.forename: Yang
authors.initials: Y
authors.lastname: Shi
authors.forename: Girija G
authors.initials: GG
authors.lastname: Konduri
mesh_terms: D055372:AMP-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000378:metabolism*; D000818:Animals; D051242:Caveolin 1 / Q000378:metabolism; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000201:enzymology; D004789:Enzyme Activation; D006976:Hypertension, Pulmonary / Q000503:physiopathology; D008687:Metformin / Q000494:pharmacology*; D018919:Neovascularization, Physiologic / Q000187:drug effects*; D052250:Nitric Oxide Synthase Type III / Q000378:metabolism; D010766:Phosphorylation; D010982:Platelet-Derived Growth Factor; D011651:Pulmonary Artery / Q000196:embryology / Q000201:enzymology; D011720:Pyrazoles / Q000494:pharmacology; D011743:Pyrimidines / Q000494:pharmacology; D017382:Reactive Oxygen Species / Q000378:metabolism; D034561:Sheep, Domestic; D013482:Superoxide Dismutase / Q000378:metabolism; D042461:Vascular Endothelial Growth Factor A / Q000096:biosynthesis
chemical_list: D051242:Caveolin 1; D010982:Platelet-Derived Growth Factor; D011720:Pyrazoles; D011743:Pyrimidines; D017382:Reactive Oxygen Species; D042461:Vascular Endothelial Growth Factor A; C516138:dorsomorphin; D008687:Metformin; D052250:Nitric Oxide Synthase Type III; D013482:Superoxide Dismutase; D055372:AMP-Activated Protein Kinases