Endothelial Extracellular Signal-Regulated Kinase 2 (ERK2)-Deficient Mice Display Increased Susceptibility to Hyperoxia-Induced Experimental Bronchopulmonary Dysplasia and Pulmonary Hypertension

Early pulmonary vascular disease in preterm infants is associated with the subsequent development of bronchopulmonary dysplasia (BPD) and pulmonary hypertension (PH); however, mechanisms that contribute to or identify infants with increased susceptibility for BPD and/or PH are incompletely understood. Therefore, we tested if changes in circulating angiogenic peptides during the first week of life are associated with the later development of BPD and/or PH. We further sought to determine alternate peptides and related signaling pathways with the risk for BPD or PH. We prospectively enrolled infants with gestational age <34 wk and collected blood samples during their first week of life. BPD and PH were assessed at 36 wk postmenstrual age. Samples were assayed for each of the 1,121 peptides included in the SOMAscan scan technology, with subsequent pathway analysis. Of 102 infants in the study, 82 had BPD, and 13 had PH. Multiple angiogenic proteins (PF-4, VEGF121, ANG-1, bone morphogenetic protein 10 [BMP10], hepatocyte growth factor (HGF), ANG-2) were associated with the subsequent diagnosis of BPD; and FGF-19, PF-4, connective tissue activating peptide (CTAP)-III, and PDGF-AA levels were associated with BPD severity. Early increases in BMP10 was strongly associated with the late risk for BPD and PH. We found that early alterations of circulating angiogenic peptides and others were associated with the subsequent development of BPD. We further identified peptides that were associated with BPD severity and BPD-associated PH, including BMP10. We speculate that proteomic biomarkers during the first week of life may identify infants at risk for BPD and/or PH to enhance care and research.

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Tie-2 Cre-Mediated Deficiency of Extracellular Signal-Regulated Kinase 2 Potentiates Experimental Bronchopulmonary Dysplasia-Associated Pulmonary Hypertension in Neonatal Mice

International Journal of Molecular Sciences ◽

10.3390/ijms21072408 ◽

2020 ◽

Vol 21 (7) ◽

pp. 2408

Author(s):

Renuka T. Menon ◽

Amrit Kumar Shrestha ◽

Roberto Barrios ◽

Corey Reynolds ◽

Binoy Shivanna

Keyword(s):

Oxidative Stress ◽

Endothelial Cells ◽

Pulmonary Hypertension ◽

Bronchopulmonary Dysplasia ◽

Neonatal Mice ◽

Expression Studies ◽

Extracellular Signal ◽

Gene And Protein Expression ◽

In Vitro Angiogenesis

Bronchopulmonary dysplasia (BPD)-associated pulmonary hypertension (PH) is a significant lung morbidity of infants, and disrupted lung angiogenesis is a hallmark of this disease. We observed that extracellular signal-regulated kinases (ERK) 1/2 support angiogenesis in vitro, and hyperoxia activates ERK1/2 in fetal human pulmonary microvascular endothelial cells (HPMECs) and in neonatal murine lungs; however, their role in experimental BPD and PH is unknown. Therefore, we hypothesized that Tie2 Cre-mediated deficiency of ERK2 in the endothelial cells of neonatal murine lungs would potentiate hyperoxia-induced BPD and PH. We initially determined the role of ERK2 in in vitro angiogenesis using fetal HPMECs. To disrupt endothelial ERK2 signaling in the lungs, we decreased ERK2 expression by breeding ERK2flox/flox mice with Tie-Cre mice. One-day-old endothelial ERK2-sufficient (eERK2+/+) or –deficient (eERK2+/−) mice were exposed to normoxia or hyperoxia (FiO2 70%) for 14 d. We then performed lung morphometry, gene and protein expression studies, and echocardiography to determine the extent of inflammation, oxidative stress, and development of lungs and PH. The knockdown of ERK2 in HPMECs decreased in vitro angiogenesis. Hyperoxia increased lung inflammation and oxidative stress, decreased lung angiogenesis and alveolarization, and induced PH in neonatal mice; however, these effects were augmented in the presence of Tie2-Cre mediated endothelial ERK2 deficiency. Therefore, we conclude that endothelial ERK2 signaling is necessary to mitigate hyperoxia-induced experimental BPD and PH in neonatal mice. Our results indicate that endothelial ERK2 is a potential therapeutic target for the management of BPD and PH in infants.

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Endothelial Adenosine Monophosphate-Activated Protein Kinase-Alpha1 Deficiency Potentiates Hyperoxia-Induced Experimental Bronchopulmonary Dysplasia and Pulmonary Hypertension

Antioxidants ◽

10.3390/antiox10121913 ◽

2021 ◽

Vol 10 (12) ◽

pp. 1913

Author(s):

Ahmed Elsaie ◽

Renuka T. Menon ◽

Amrit K. Shrestha ◽

Sharada H. Gowda ◽

Nidhy P. Varghese ◽

...

Keyword(s):

Pulmonary Hypertension ◽

Protein Kinase ◽

Lung Injury ◽

Bronchopulmonary Dysplasia ◽

Adenosine Monophosphate ◽

Causative Factor ◽

Nuclear Antigen ◽

Tubule Formation ◽

Neonatal Mice ◽

Deficient Mice

Bronchopulmonary dysplasia and pulmonary hypertension, or BPD-PH, are serious chronic lung disorders of prematurity, without curative therapies. Hyperoxia, a known causative factor of BPD-PH, activates adenosine monophosphate-activated protein kinase (AMPK) α1 in neonatal murine lungs; however, whether this phenomenon potentiates or mitigates lung injury is unclear. Thus, we hypothesized that (1) endothelial AMPKα1 is necessary to protect neonatal mice against hyperoxia-induced BPD-PH, and (2) AMPKα1 knockdown decreases angiogenesis in hyperoxia-exposed neonatal human pulmonary microvascular endothelial cells (HPMECs). We performed lung morphometric and echocardiographic studies on postnatal day (P) 28 on endothelial AMPKα1-sufficient and -deficient mice exposed to 21% O2 (normoxia) or 70% O2 (hyperoxia) from P1–P14. We also performed tubule formation assays on control- or AMPKα1-siRNA transfected HPMECs, exposed to 21% O2 or 70% O2 for 48 h. Hyperoxia-mediated alveolar and pulmonary vascular simplification, pulmonary vascular remodeling, and PH were significantly amplified in endothelial AMPKα1-deficient mice. AMPKα1 siRNA knocked down AMPKα1 expression in HPMECs, and decreased their ability to form tubules in normoxia and hyperoxia. Furthermore, AMPKα1 knockdown decreased proliferating cell nuclear antigen expression in hyperoxic conditions. Our results indicate that AMPKα1 is required to reduce hyperoxia-induced BPD-PH burden in neonatal mice, and promotes angiogenesis in HPMECs to limit lung injury.

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