title: Adrenomedullin deficiency potentiates hyperoxic injury in fetal human pulmonary microvascular endothelial cells.
abstract: Bronchopulmonary dysplasia (BPD) is a chronic lung disease of premature infants that is characterized by alveolar simplification and decreased lung angiogenesis. Hyperoxia-induced oxidative stress and inflammation contributes to the development of BPD in premature infants. Adrenomedullin (AM) is an endogenous peptide with potent angiogenic, anti-oxidant, and anti-inflammatory properties. Whether AM regulates hyperoxic injury in fetal primary human lung cells is unknown. Therefore, we tested the hypothesis that AM-deficient fetal primary human pulmonary microvascular endothelial cells (HPMEC) will have increased oxidative stress, inflammation, and cytotoxicity compared to AM-sufficient HPMEC upon exposure to hyperoxia. Adrenomedullin gene (Adm) was knocked down in HPMEC by siRNA-mediated transfection and the resultant AM-sufficient and -deficient cells were evaluated for hyperoxia-induced oxidative stress, inflammation, cytotoxicity, and Akt activation. AM-deficient HPMEC had significantly increased hyperoxia-induced reactive oxygen species (ROS) generation and cytotoxicity compared to AM-sufficient HPMEC. Additionally, AM-deficient cell culture supernatants had increased macrophage inflammatory protein 1α and 1β, indicating a heightened inflammatory state. Interestingly, AM deficiency was associated with an abrogated Akt activation upon exposure to hyperoxia. These findings support the hypothesis that AM deficiency potentiates hyperoxic injury in primary human fetal HPMEC via mechanisms entailing Akt activation.
authors.affiliation: Section of Neonatology, Department of Pediatrics, Baylor College of Medicine, Houston, TX, USA.
authors.forename: Shaojie
authors.initials: S
authors.lastname: Zhang
authors.affiliation: Section of Neonatology, Department of Pediatrics, Baylor College of Medicine, Houston, TX, USA.
authors.forename: Ananddeep
authors.initials: A
authors.lastname: Patel
authors.affiliation: Section of Neonatology, Department of Pediatrics, Baylor College of Medicine, Houston, TX, USA.
authors.forename: Bhagavatula
authors.initials: B
authors.lastname: Moorthy
authors.affiliation: Section of Neonatology, Department of Pediatrics, Baylor College of Medicine, Houston, TX, USA. Electronic address: shivanna@bcm.edu.
authors.forename: Binoy
authors.initials: B
authors.lastname: Shivanna
mesh_terms: D053607:Adrenomedullin / Q000172:deficiency* / Q000235:genetics / Q000378:metabolism; D001997:Bronchopulmonary Dysplasia / Q000209:etiology / Q000378:metabolism / Q000473:pathology; D016923:Cell Death; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000378:metabolism* / Q000473:pathology; D005333:Fetus / Q000098:blood supply / Q000378:metabolism; D055785:Gene Knockdown Techniques; D006801:Humans; D018496:Hyperoxia / Q000209:etiology* / Q000378:metabolism / Q000473:pathology; D007231:Infant, Newborn; D008168:Lung / Q000098:blood supply* / Q000378:metabolism; D055370:Lung Injury / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D018384:Oxidative Stress; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism
chemical_list: C507862:ADM protein, human; D053607:Adrenomedullin; D051057:Proto-Oncogene Proteins c-akt
keywords: Adrenomedullin; Akt; Fetal HPMEC; Hyperoxic injury; Inflammation