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Fetal pulmonary hypertension: dysregulated microRNA-34c-Notch1 axis contributes to impaired angiogenesis in an ovine model. Pediatr Res 2023; 93:551-558. [PMID: 35717485 PMCID: PMC9759620 DOI: 10.1038/s41390-022-02151-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Revised: 05/17/2022] [Accepted: 05/26/2022] [Indexed: 11/09/2022]
Abstract
BACKGROUND Persistent pulmonary hypertension of the newborn (PPHN) occurs when pulmonary vascular resistance (PVR) fails to decrease at birth. Decreased angiogenesis in the lung contributes to the persistence of high PVR at birth. MicroRNAs (miRNAs) regulate gene expression through transcript binding and degradation. They were implicated in dysregulated angiogenesis in cancer and cardiovascular disease. METHODS We investigated whether altered miRNA levels contribute to impaired angiogenesis in PPHN. We used a fetal lamb model of PPHN induced by prenatal ductus arteriosus constriction and sham ligation as controls. We performed RNA sequencing of pulmonary artery endothelial cells (PAECs) isolated from control and PPHN lambs. RESULTS We observed a differentially expressed miRNA profile in PPHN for organ development, cell-cell signaling, and cardiovascular function. MiR-34c was upregulated in PPHN PAECs compared to controls. Exogenous miR34c mimics decreased angiogenesis by control PAEC and anti-miR34c improved angiogenesis of PPHN PAEC in vitro. Notch1, a predicted target for miR-34c by bioinformatics, was decreased in PPHN PAECs, along with Notch1 downstream targets, Hey1 and Hes1. Exogenous miR-34c decreased Notch1 expression in control PAECs and anti-miR-34c restored Notch1 and Hes1 expression in PPHN PAECs. CONCLUSION We conclude that increased miR-34c in PPHN contributes to impaired angiogenesis by decreasing Notch1 expression in PAECs. IMPACT Adds a novel mechanism for the regulation of angiogenesis in persistent pulmonary hypertension of the newborn. Identifies non-coding RNAs that are involved in the altered angiogenesis in PPHN and thus the potential for future studies to identify links between known pathways regulating angiogenesis. Provides preliminary data to conduct studies targeting miR34c expression in vivo in animal models of pulmonary hypertension to identify the mechanistic role of miR34c in angiogenesis in the lung vasculature.
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Mukherjee D, Konduri GG. Pediatric Pulmonary Hypertension: Definitions, Mechanisms, Diagnosis, and Treatment. Compr Physiol 2021; 11:2135-2190. [PMID: 34190343 PMCID: PMC8289457 DOI: 10.1002/cphy.c200023] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Pediatric pulmonary hypertension (PPH) is a multifactorial disease with diverse etiologies and presenting features. Pulmonary hypertension (PH), defined as elevated pulmonary artery pressure, is the presenting feature for several pulmonary vascular diseases. It is often a hidden component of other lung diseases, such as cystic fibrosis and bronchopulmonary dysplasia. Alterations in lung development and genetic conditions are an important contributor to pediatric pulmonary hypertensive disease, which is a distinct entity from adult PH. Many of the causes of pediatric PH have prenatal onset with altered lung development due to maternal and fetal conditions. Since lung growth is altered in several conditions that lead to PPH, therapy for PPH includes both pulmonary vasodilators and strategies to restore lung growth. These strategies include optimal alveolar recruitment, maintaining physiologic blood gas tension, nutritional support, and addressing contributing factors, such as airway disease and gastroesophageal reflux. The outcome for infants and children with PH is highly variable and largely dependent on the underlying cause. The best outcomes are for neonates with persistent pulmonary hypertension (PPHN) and reversible lung diseases, while some genetic conditions such as alveolar capillary dysplasia are lethal. © 2021 American Physiological Society. Compr Physiol 11:2135-2190, 2021.
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Affiliation(s)
- Devashis Mukherjee
- Division of Neonatology, Department of Pediatrics, Medical College of Wisconsin, Children’s Research Institute, Children’s Wisconsin, Milwaukee, Wisconsin, 53226 USA
| | - Girija G. Konduri
- Division of Neonatology, Department of Pediatrics, Medical College of Wisconsin, Children’s Research Institute, Children’s Wisconsin, Milwaukee, Wisconsin, 53226 USA
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Sharma M, Rana U, Joshi C, Michalkiewicz T, Afolayan A, Parchur A, Joshi A, Teng RJ, Konduri GG. Decreased Cyclic GMP-protein Kinase G signaling impairs Angiogenesis in a Lamb Model of Persistent Pulmonary Hypertension of Newborn. Am J Respir Cell Mol Biol 2021; 65:555-567. [PMID: 34185619 DOI: 10.1165/rcmb.2020-0434oc] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Impaired angiogenesis function of pulmonary artery endothelial cells (PAEC) contributes to persistent pulmonary hypertension of the newborn (PPHN). Decreased nitric oxide (NO) levels in PPHN lead to impaired mitochondrial biogenesis and angiogenesis in the lung; the mechanisms remain unclear. We hypothesized that decreased cGMP-Protein kinase G (PKG) signaling downstream of NO leads to decreased mitochondrial biogenesis and angiogenesis in PPHN. PPHN was induced by ductus arteriosus constriction from 128-136d gestation in fetal lambs. Controls were gestation matched lambs without ductal constriction. PAEC isolated from PPHN lambs were treated with soluble guanylyl cyclase activator, cinaciguat, PKG activator, 8-Br-cGMP or phosphodiesterase-V inhibitor, sildenafil. Lysates were immunoblotted for mitochondrial transcription factors and electron transport chain (ETC) complex proteins I-V. In vitro angiogenesis of PAEC was evaluated by tube formation and scratch recovery assays. cGMP levels were measured by enzyme immunoassay. Fetal lambs with ductal constriction were given sildenafil or control saline by continuous infusion in utero and lung histology, capillary counts, vessel density and right ventricular pressure were assessed at birth. PPHN PAEC showed decreased mitochondrial transcription factors, ETC proteins, and in vitro tube formation and cell migration; these were restored by cinaciguat, 8-Br-cGMP and sildenafil. Cinaciguat and sildenafil increased cGMP levels in PPHN PAEC. Radial alveolar and capillary counts and vessel density were lower and RV pressure and Fulton index higher in PPHN lungs; these were improved by in utero sildenafil infusion. cGMP-PKG signaling is a potential therapeutic target to restore decreased mitochondrial biogenesis and angiogenesis in PPHN.
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Affiliation(s)
- Megha Sharma
- University of Arkansas for Medical Sciences, 12215, Little Rock, Arkansas, United States
| | - Ujala Rana
- Medical College of Wisconsin, 5506, Pediatrics, Milwaukee, Wisconsin, United States
| | - Chintamani Joshi
- Medical College of Wisconsin, 5506, Milwaukee, Wisconsin, United States
| | | | - Adeleye Afolayan
- Medical College of Wisconsin, 5506, Milwaukee, Wisconsin, United States
| | - Abdul Parchur
- Medical College of Wisconsin, 5506, Milwaukee, Wisconsin, United States
| | - Amit Joshi
- Medical College of Wisconsin, 5506, Milwaukee, Wisconsin, United States
| | - Ru-Jeng Teng
- Medical College of Wisconsin, 5506, Pediatrics, Milwaukee, Wisconsin, United States
| | - Girija G Konduri
- Medical College of Wisconsin, 5506, Pediatrics, Milwaukee, Wisconsin, United States;
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Alzghoul BN, Hamburger R, Lewandowski T, Janssen B, Grey D, Xue W, Ataya A, Alnuaimat H, Gomez-Manjarres DC, Patel D, Reddy R. Pulmonary hypertension in patients with interstitial pneumonia with autoimmune features. Pulm Circ 2020; 10:2045894020944117. [PMID: 33343878 DOI: 10.1177/2045894020944117] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Accepted: 06/29/2020] [Indexed: 11/16/2022] Open
Abstract
Pulmonary hypertension in interstitial lung diseases is associated with increased mortality and hospitalizations and reduced exercise capacity. Interstitial pneumonia with autoimmune features (IPAF) is a recently described interstitial lung disease. The characteristics of pulmonary hypertension in IPAF patients are unknown. We sought to characterize patients with IPAF based on their echocardiographic probability of pulmonary hypertension and compare patients with and without pulmonary hypertension identified by right heart catheterization. We conducted a retrospective study of patients seen in the interstitial lung disease clinic from 2015 to 2018. Forty-seven patients with IPAF were identified. Patients were classified into low, intermediate and high echocardiographic pulmonary hypertension probabilities. A sub-group analysis of patients with pulmonary hypertension and without pulmonary hypertension (IPAF-PH vs. IPAF-no PH) identified by right heart catheterization was also performed. Linear regression analysis was performed to study the association between 6-min-walk-distance (6MWD) and pulmonary vascular resistance (PVR) while adjusting for age and body mass index. Right ventricular hypertrophy (>5 mm), right ventricular enlargement (>41 mm) and right ventricular systolic dysfunction defined as fractional area change% ≤35 was present in 76%, 24%, and 39% of patients, respectively. Pulmonary hypertension was identified in 12.7% of patients. IPAF-PH patients had higher mean pulmonary artery pressure and lower cardiac output compared to the IPAF-no PH group (34 mmHg vs. 19 mmHg, p = 0.002 and 4.0 vs. 5.7 L/min, p = 0.023, respectively). Lower 6MWD was associated with higher PVR on regression analysis (p = 0.002). Pulmonologists should be aware that a significant number of IPAF patients may develop pulmonary hypertension. Reduced 6MWD may suggest the presence of pulmonary hypertension in IPAF patients.
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Affiliation(s)
- Bashar N Alzghoul
- Division of Pulmonary, Critical Care and Sleep Medicine, University of Florida, Gainesville, FL, USA
| | - Robert Hamburger
- Division of Cardiovascular Medicine, University of Florida, Gainesville, FL, USA
| | - Thomas Lewandowski
- Division of Cardiovascular Medicine, University of Florida, Gainesville, FL, USA
| | - Brandon Janssen
- Department of Internal Medicine, University of Florida, Gainesville, FL, USA
| | - Daniel Grey
- Department of Internal Medicine, University of Florida, Gainesville, FL, USA
| | - Wei Xue
- Department of Biostatistics, College of Public Health and Health Professions and College of Medicine, University of Florida, Gainesville, FL, USA
| | - Ali Ataya
- Division of Pulmonary, Critical Care and Sleep Medicine, University of Florida, Gainesville, FL, USA
| | - Hassan Alnuaimat
- Division of Pulmonary, Critical Care and Sleep Medicine, University of Florida, Gainesville, FL, USA
| | - Diana C Gomez-Manjarres
- Division of Pulmonary, Critical Care and Sleep Medicine, University of Florida, Gainesville, FL, USA
| | - Divya Patel
- Division of Pulmonary, Critical Care and Sleep Medicine, University of Florida, Gainesville, FL, USA
| | - Raju Reddy
- Division of Pulmonary, Critical Care and Sleep Medicine, University of Florida, Gainesville, FL, USA
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5
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Rana U, Callan E, Entringer B, Michalkiewicz T, Joshi A, Parchur AK, Teng RJ, Konduri GG. AMP-Kinase Dysfunction Alters Notch Ligands to Impair Angiogenesis in Neonatal Pulmonary Hypertension. Am J Respir Cell Mol Biol 2020; 62:719-731. [PMID: 32048878 DOI: 10.1165/rcmb.2019-0275oc] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Decreased angiogenesis contributes to persistent pulmonary hypertension of the newborn (PPHN); mechanisms remain unclear. AMPK (5'AMP activated protein kinase) is a key regulator of cell metabolism. We investigated the hypothesis that a decrease in AMPK function leads to mitochondrial dysfunction and altered balance of notch ligands delta-like 4 (DLL4) and Jagged 1 (Jag1) to impair angiogenesis in PPHN. Studies were done in fetal lambs with PPHN induced by prenatal ductus arteriosus constriction and gestation-matched control lambs. PPHN lambs were treated with saline or AMPK agonist metformin. Angiogenesis was assessed in lungs with micro-computed tomography angiography and histology. AMPK function; expression of mitochondrial electron transport chain (ETC) complex proteins I-V, Dll4, and Jag1; mitochondrial number; and in vitro angiogenesis function were assessed in pulmonary artery endothelial cells (PAEC) from control and PPHN lambs. AMPK function was decreased in PPHN PAEC and lung sections. Expression of mitochondrial transcription factor, PGC-1α, ETC complex proteins I-V, and mitochondrial number were decreased in PPHN. In vitro angiogenesis of PAEC and capillary number and vessel volume fraction in the lung were decreased in PPHN. Expression of DLL4 was increased and Jag1 was decreased in PAEC from PPHN lambs. AMPK agonists A769662 and metformin increased the mitochondrial complex proteins and number, in vitro angiogenesis, and Jag1 levels and decreased DLL4 levels in PPHN PAEC. Infusion of metformin in vivo increased the vessel density in PPHN lungs. Decreased AMPK function contributes to impaired angiogenesis in PPHN by altered balance of notch ligands in PPHN.
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Affiliation(s)
- Ujala Rana
- Department of Pediatrics and Children's Research Institute, and
| | - Emily Callan
- Department of Pediatrics and Children's Research Institute, and
| | | | | | - Amit Joshi
- Department of Radiology and Center for Imaging, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Abdul K Parchur
- Department of Radiology and Center for Imaging, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Ru-Jeng Teng
- Department of Pediatrics and Children's Research Institute, and
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6
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Trittmann JK, Almazroue H, Jin Y, Nelin LD. DDAH1 regulates apoptosis and angiogenesis in human fetal pulmonary microvascular endothelial cells. Physiol Rep 2020; 7:e14150. [PMID: 31209995 PMCID: PMC6579941 DOI: 10.14814/phy2.14150] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 05/30/2019] [Accepted: 06/01/2019] [Indexed: 01/17/2023] Open
Abstract
Nitric Oxide (NO) is an endogenous pulmonary vasodilator produced by endothelial NO synthase (eNOS). Asymmetric dimethyl L‐arginine (ADMA) is an endogenous inhibitor of eNOS activity. In endothelial cells, ADMA is hydrolyzed to L‐citrulline primarily by dimethylarginine dimethyl‐aminohydrolase‐1 (DDAH1). We tested the hypothesis that DDAH1 expression is essential for maintaining NO production in human fetal pulmonary microvascular endothelial cells (hfPMVEC), such that knockdown of DDAH1 expression will lead to decreased NO production resulting in less caspase‐3 activation and less tube formation. We found that hfPMVEC transfected with DDAH1 siRNA had lower NO production than control, with no difference in eNOS protein levels between groups. hfPMVEC transfected with DDAH1 siRNA had lower protein levels of cleaved caspase‐3 and ‐8 than control. Both DDAH1 siRNA‐ and ADMA‐treated hfPMVEC had greater numbers of viable cells than controls. Angiogenesis was assessed using tube formation assays in matrigel, and tube formation was lower after either DDAH1 siRNA transfection or ADMA treatment than controls. Addition of an NO donor restored cleaved caspase‐3 and ‐8 protein levels after DDAH1 siRNA transfection in hfPMVEC to essentially the levels seen in scramble control. Addition of a putative caspase‐3 inhibitor to DDAH1 siRNA transfected and NO‐donor treated cells led to greater numbers of viable cells and far less angiogenesis than in any other group studied. We conclude that in hfPMVEC, DDAH1 is central to the regulation of NO‐mediated caspase‐3 activation and the resultant apoptosis and angiogenesis. Our findings suggest that DDAH1 may be a potential therapeutic target in pulmonary hypertensive disorders.
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Affiliation(s)
- Jennifer K Trittmann
- Pulmonary Hypertension Group, Center for Perinatal Research, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, Ohio.,Department of Pediatrics, The Ohio State University, Columbus, Ohio
| | - Hanadi Almazroue
- Pulmonary Hypertension Group, Center for Perinatal Research, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, Ohio
| | - Yi Jin
- Pulmonary Hypertension Group, Center for Perinatal Research, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, Ohio
| | - Leif D Nelin
- Pulmonary Hypertension Group, Center for Perinatal Research, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, Ohio.,Department of Pediatrics, The Ohio State University, Columbus, Ohio
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7
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Steinhorn RH, Lakshminrusimha S. Oxygen and pulmonary vasodilation: The role of oxidative and nitrosative stress. Semin Fetal Neonatal Med 2020; 25:101083. [PMID: 31983672 DOI: 10.1016/j.siny.2020.101083] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Respiratory failure complicates up to 2% of live births and contributes significantly to neonatal morbidity and mortality. Under these conditions, supplemental oxygen is required to support oxygen delivery to the brain and other organs, and to prevent hypoxic pulmonary vasoconstriction. However, therapeutic oxygen is also a source of reactive oxygen species that produce oxidative stress, along with multiple intracellular systems that contribute to the production of free radicals in pulmonary endothelium and vascular smooth muscle. These free radicals cause vasoconstriction, act on multiple sites of the nitric oxide pathway to reduce cGMP-mediated vasodilation, and nitrate and inactivate essential proteins such as surfactant. In addition to oxygen, antenatal stressors such as placental insufficiency, maternal diabetes, and fetal growth restriction increase pulmonary and vascular oxidant stress and may amplify the adverse effects of oxygen. Moreover, the effects of free radical damage may extend well beyond infancy as suggested by the increased risk of childhood malignancy after neonatal exposure to hyperoxia. Antioxidant therapy is theoretically promising, but there are not yet clinical trials to support this approach. Targeting the abnormal sources of increased oxidant stress that trigger abnormal pulmonary vascular responses may be more effective in treating disease and preventing long term consequences.
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Affiliation(s)
- Robin H Steinhorn
- George Washington University, Senior Vice President, Children's National Hospital, Washington, DC, 20010, USA.
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8
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Rafikova O, Al Ghouleh I, Rafikov R. Focus on Early Events: Pathogenesis of Pulmonary Arterial Hypertension Development. Antioxid Redox Signal 2019; 31:933-953. [PMID: 31169021 PMCID: PMC6765063 DOI: 10.1089/ars.2018.7673] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Revised: 06/03/2019] [Accepted: 06/03/2019] [Indexed: 12/17/2022]
Abstract
Significance: Pulmonary arterial hypertension (PAH) is a progressive disease of the lung vasculature characterized by the proliferation of all vascular wall cell types, including endothelial, smooth muscle, and fibroblasts. The disease rapidly advances into a form with extensive pulmonary vascular remodeling, leading to a rapid increase in pulmonary vascular resistance, which results in right heart failure. Recent Advances: Most current research in the PAH field has been focused on the late stage of the disease, largely due to an urgent need for patient treatment options in clinics. Further, the pathobiology of PAH is multifaceted in the advanced disease, and there has been promising recent progress in identifying various pathological pathways related to the late clinical picture. Critical Issues: Early stage PAH still requires additional attention from the scientific community, and although the survival of patients with early diagnosis is comparatively higher, the disease develops in patients asymptomatically, making it difficult to identify and treat early. Future Directions: There are several reasons to focus on the early stage of PAH. First, the complexity of late stage disease, owing to multiple pathways being activated in a complex system with intra- and intercellular signaling, leads to an unclear picture of the key contributors to the pathobiology. Second, an understanding of early pathophysiological events can increase the ability to identify PAH patients earlier than what is currently possible. Third, the prompt diagnosis of PAH would allow for the therapy to start earlier, which has proved to be a more successful strategy, and it ensures better survival in PAH patients.
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Affiliation(s)
- Olga Rafikova
- Division of Endocrinology, Department of Medicine, University of Arizona, Tucson, Arizona
| | - Imad Al Ghouleh
- Heart, Lung, Blood, and Vascular Medicine Institute, Division of Cardiology, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Ruslan Rafikov
- Division of Endocrinology, Department of Medicine, University of Arizona, Tucson, Arizona
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9
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Perez M, Robbins ME, Revhaug C, Saugstad OD. Oxygen radical disease in the newborn, revisited: Oxidative stress and disease in the newborn period. Free Radic Biol Med 2019; 142:61-72. [PMID: 30954546 PMCID: PMC6791125 DOI: 10.1016/j.freeradbiomed.2019.03.035] [Citation(s) in RCA: 106] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Revised: 03/06/2019] [Accepted: 03/29/2019] [Indexed: 12/28/2022]
Abstract
Thirty years ago, there was an emerging appreciation for the significance of oxidative stress in newborn disease. This prompted a renewed interest in the impact of oxygen therapy for the newborn in the delivery room and beyond, especially in premature infants. Today, the complexity of oxidative stress both in normal regulation and pathology is better understood, especially as it relates to neonatal mitochondrial oxidative stress responses to hyperoxia. Mitochondria are recipients of oxidative damage and have a propensity for oxidative self-injury that has been implicated in the pathogenesis of neonatal lung diseases. Similarly, both intrauterine growth restriction (IUGR) and macrosomia are associated with mitochondrial dysfunction and oxidative stress. Additionally, reoxygenation with 100% O2 in a hypoxic-ischemic newborn lamb model increased the production of pro-inflammatory cytokines in the brain. Moreover, the interplay between inflammation and oxidative stress in the newborn is better understood because of animal studies. Transcriptomic analyses have found a number of genes to be differentially expressed in murine models of bronchopulmonary dysplasia (BPD). Epigenetic changes have also been detected both in animal models of BPD and premature infants exposed to oxygen. Antioxidant therapy to prevent newborn disease has not been very successful; however, new therapeutic principles, like melatonin, are under investigation.
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Affiliation(s)
- Marta Perez
- Division of Neonatology, Stanley Manne Children's Research Institute, Ann and Robert H Lurie Children's Hospital, Chicago, IL, United States; Department of Pediatrics, Northwestern University, Feinberg School of Medicine, Chicago, IL, United States
| | - Mary E Robbins
- Division of Neonatology, Stanley Manne Children's Research Institute, Ann and Robert H Lurie Children's Hospital, Chicago, IL, United States; Department of Pediatrics, Northwestern University, Feinberg School of Medicine, Chicago, IL, United States
| | - Cecilie Revhaug
- Department of Pediatric Research, University of Oslo, Oslo University Hospital, Norway
| | - Ola D Saugstad
- Department of Pediatrics, Northwestern University, Feinberg School of Medicine, Chicago, IL, United States; Department of Pediatric Research, University of Oslo, Oslo University Hospital, Norway.
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Wedgwood S, Steinhorn RH, Lakshminrusimha S. Optimal oxygenation and role of free radicals in PPHN. Free Radic Biol Med 2019; 142:97-106. [PMID: 30995536 PMCID: PMC6761018 DOI: 10.1016/j.freeradbiomed.2019.04.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Accepted: 04/01/2019] [Indexed: 02/07/2023]
Abstract
Effective ventilation of the lungs is essential in mediating pulmonary vasodilation at birth to allow effective gas exchange and an increase in systemic oxygenation. Unsuccessful transition prevents the increase in pulmonary blood flow after birth resulting in hypoxemia and persistent pulmonary hypertension of the newborn (PPHN). Management of neonates with PPHN includes ventilation of the lungs with supplemental oxygen to correct hypoxemia. Optimal oxygenation should meet oxygen demand to the tissues and avoid hypoxic pulmonary vasoconstriction (HPV) while preventing oxidative stress. The optimal target for oxygenation in PPHN is not known. Animal models have demonstrated that PaO2<45 mmHg exacerbates HPV. However, there are no practical methods of assessing oxygen levels associated with oxidant stress. Oxidant stress can be due to free radical generation from underlying lung disease or from free radicals generated by supplemental oxygen. Free radicals act on the nitric oxide pathway reducing cGMP and promoting pulmonary vasoconstriction. Antioxidant therapy improves systemic oxygenation in an animal model of PPHN but there are no clinical trials to support such therapy. Targeting preductal SpO2 between 90 and 97% and PaO2 at 50-80 mmHg appears prudent in PPHN but clinical trials to support this practice are lacking. Preterm infants with PPHN present unique challenges due to lack of antioxidant defenses and functional and structural immaturity of the lungs. This review highlights the need for additional studies to mitigate the impact of oxidative stress in the lung and pulmonary vasculature in PPHN.
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Affiliation(s)
- Stephen Wedgwood
- Department of Pediatrics, UC Davis School of Medicine, Sacramento, CA, USA
| | - Robin H Steinhorn
- Department of Hospitalist Medicine, Children's National Health System, Washington DC, USA
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Cohen S, Liu Q, Wright M, Garvin J, Rarick K, Harder D. High glucose conditioned neonatal astrocytes results in impaired mitogenic activity in cerebral microvessel endothelial cells in co-culture. Heliyon 2019; 5:e01795. [PMID: 31193586 PMCID: PMC6536426 DOI: 10.1016/j.heliyon.2019.e01795] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2018] [Revised: 04/22/2019] [Accepted: 05/20/2019] [Indexed: 11/20/2022] Open
Abstract
Angiogenesis is a highly complex and coordinated process in the brain. Under normal conditions, it is a vital process in growth and development, but under adverse conditions such as diabetes mellitus, it can lead to severe pathology. Astrocytes are a key constituent of the neurovascular unit and contribute to cerebral function, not only bridging the gap between metabolic supplies from blood vessels to neurons, but also regulating angiogenesis. Astrocytes affect angiogenesis by secreting angiogenic factors such as vascular endothelial growth factor (VEGF) into its microenvironment and regulating mitogenic activity in cerebral microvessel endothelial cells (CMEC). We hypothesized that astrocytes conditioned in high glucose media would produce and secrete decreased VEGF which would lead to impaired proliferation, migration, and tube formation of CMEC in vitro. Using neonatal rat astrocytes, we used normal glucose (NG, 5.5mM) vs. high glucose (HG, 25mM) feeding media and measured VEGF message and protein levels as well as secreted VEGF. We co-cultured conditioned astrocytes with isolated rat CMEC and measured mitogenic activity of endothelial cells using BrdU assay, scratch recovery assay, and tube formation assay. HG astrocytes produced and secreted decreased VEGF protein and resulted in impaired mitogenic activity when co-cultured with CMEC as demonstrated by decreased BrdU uptake, decreased scratch recovery, and slower tube formation. Our study provides insight into gliovascular adaptations to increased glucose levels resulting in impaired cellular cross-talk between astrocytes and CMEC which could be one explanation for cerebral microangiopathy seen in diabetic conditions.
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Affiliation(s)
- Susan Cohen
- Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI, USA
- Corresponding author.
| | - Qiuli Liu
- Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI, USA
| | | | - Jodi Garvin
- Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Kevin Rarick
- Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI, USA
| | - David Harder
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, USA
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12
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Makker K, Afolayan AJ, Teng R, Konduri GG. Altered hypoxia-inducible factor-1α (HIF-1α) signaling contributes to impaired angiogenesis in fetal lambs with persistent pulmonary hypertension of the newborn (PPHN). Physiol Rep 2019; 7:e13986. [PMID: 30706701 PMCID: PMC6355993 DOI: 10.14814/phy2.13986] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Revised: 12/26/2018] [Accepted: 12/26/2018] [Indexed: 01/08/2023] Open
Abstract
Previous studies in adult pulmonary hypertension reported that increased hypoxia-inducible factor-1α (HIF-1α) signaling contributes to pulmonary vascular remodeling. However, alterations in endothelial HIF-1α signaling and its contribution to impaired angiogenesis in persistent pulmonary hypertension of the newborn (PPHN) remain unclear. We investigated the hypothesis that HIF-1α levels are increased in lung endothelial cells in PPHN and contribute to impaired angiogenesis function. We examined HIF-1α expression and promoter activity in the isolated pulmonary artery endothelial cells (PAEC) from fetal lambs with or without PPHN induced by prenatal ductus arteriosus constriction. We measured the levels of HIF-1α downstream targets, vascular endothelial growth factor (VEGF) and glycolytic protein, hexokinase 2 (Hek-2) in PAEC from PPHN, and control lambs. We examined the effect of small interfering-RNA (siRNA) mediated knockdown of native HIF-1α on VEGF expression and in vitro angiogenesis function of PPHN-PAEC. HIF-1α protein levels were higher in the isolated PAEC from PPHN-lambs compared to controls. HIF-1α promoter activity and Hek-2 protein levels were higher in PPHN. VEGF protein levels and in vitro angiogenesis function were decreased in PAEC from PPHN lambs. HIF-1α silencing significantly increased the expression of VEGF and improved the angiogenesis function of PPHN PAEC. Aberrant HIF-1α signaling contributes to endothelial dysfunction and decreased angiogenesis in PPHN.
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Affiliation(s)
- Kartikeya Makker
- Department of PediatricsUniversity of Florida College of MedicineJacksonvilleFlorida
| | - Adeleye J. Afolayan
- Department of PediatricsCardiovascular Research Center and Children's Research InstituteMedical College of WisconsinMilwaukeeWisconsin
| | - Ru‐Jeng Teng
- Department of PediatricsCardiovascular Research Center and Children's Research InstituteMedical College of WisconsinMilwaukeeWisconsin
| | - Girija G. Konduri
- Department of PediatricsCardiovascular Research Center and Children's Research InstituteMedical College of WisconsinMilwaukeeWisconsin
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Ducsay CA, Goyal R, Pearce WJ, Wilson S, Hu XQ, Zhang L. Gestational Hypoxia and Developmental Plasticity. Physiol Rev 2018; 98:1241-1334. [PMID: 29717932 PMCID: PMC6088145 DOI: 10.1152/physrev.00043.2017] [Citation(s) in RCA: 105] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Hypoxia is one of the most common and severe challenges to the maintenance of homeostasis. Oxygen sensing is a property of all tissues, and the response to hypoxia is multidimensional involving complicated intracellular networks concerned with the transduction of hypoxia-induced responses. Of all the stresses to which the fetus and newborn infant are subjected, perhaps the most important and clinically relevant is that of hypoxia. Hypoxia during gestation impacts both the mother and fetal development through interactions with an individual's genetic traits acquired over multiple generations by natural selection and changes in gene expression patterns by altering the epigenetic code. Changes in the epigenome determine "genomic plasticity," i.e., the ability of genes to be differentially expressed according to environmental cues. The genomic plasticity defined by epigenomic mechanisms including DNA methylation, histone modifications, and noncoding RNAs during development is the mechanistic substrate for phenotypic programming that determines physiological response and risk for healthy or deleterious outcomes. This review explores the impact of gestational hypoxia on maternal health and fetal development, and epigenetic mechanisms of developmental plasticity with emphasis on the uteroplacental circulation, heart development, cerebral circulation, pulmonary development, and the hypothalamic-pituitary-adrenal axis and adipose tissue. The complex molecular and epigenetic interactions that may impact an individual's physiology and developmental programming of health and disease later in life are discussed.
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Affiliation(s)
- Charles A. Ducsay
- The Lawrence D. Longo, MD Center for Perinatal Biology, Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, California
| | - Ravi Goyal
- The Lawrence D. Longo, MD Center for Perinatal Biology, Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, California
| | - William J. Pearce
- The Lawrence D. Longo, MD Center for Perinatal Biology, Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, California
| | - Sean Wilson
- The Lawrence D. Longo, MD Center for Perinatal Biology, Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, California
| | - Xiang-Qun Hu
- The Lawrence D. Longo, MD Center for Perinatal Biology, Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, California
| | - Lubo Zhang
- The Lawrence D. Longo, MD Center for Perinatal Biology, Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, California
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Wu J, Zhang W, Liu X, Wu L, He G, Li P, Guo X, Chen Z, Huang Q. Apocynin protects endothelial cells from endoplasmic reticulum stress-induced apoptosis via IRE1α engagement. Mol Cell Biochem 2018; 449:257-265. [PMID: 29696609 PMCID: PMC7088535 DOI: 10.1007/s11010-018-3362-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Accepted: 04/16/2018] [Indexed: 12/22/2022]
Abstract
Endoplasmic reticulum (ER) stress-induced endothelial cell (EC) apoptosis has been implicated in a variety of human diseases. In addition to being regarded as an NADPH oxidase (NOX) inhibitor, apocynin (APO) exhibits an anti-apoptotic effect in various cells. The present study aimed to identify the protective role of apocynin in ER stress-mediated EC apoptosis and the underlying mechanisms. We found that ER stress resulted in a significant increase in c-Jun N-terminal kinase phosphorylation, and elicited caspase 3 cleavage and apoptosis. However, apocynin obviously attenuated EC apoptosis and this effect was partly dependent on ER stress sensor inositol-requiring enzyme 1α (IRE1α). Importantly, apocynin upregulated IRE1α expression in both protein and mRNA levels and promoted the pro-survival XBP1 splicing. Our results suggest that apocynin protects ECs against ER stress-induced apoptosis via IRE1α involvement. These findings may provide a novel mechanistic explanation for the anti-apoptotic effect of apocynin in ER stress.
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Affiliation(s)
- Jie Wu
- The First School of Clinical Medicine, Southern Medical University, Guangzhou, China.,Department of Critical Care Medicine, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Weijin Zhang
- The First School of Clinical Medicine, Southern Medical University, Guangzhou, China.,Department of Critical Care Medicine, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Xiaohui Liu
- The First School of Clinical Medicine, Southern Medical University, Guangzhou, China
| | - Lili Wu
- Guangdong Provincial Key Laboratory of Shock and Microcirculation, School of Basic Medical Sciences, Southern Medical University, No. 1023, South Shatai Road, Guangzhou, 510515, Guangdong, China
| | - Guangting He
- The First School of Clinical Medicine, Southern Medical University, Guangzhou, China
| | - Peixin Li
- The First School of Clinical Medicine, Southern Medical University, Guangzhou, China
| | - Xiaohua Guo
- Guangdong Provincial Key Laboratory of Shock and Microcirculation, School of Basic Medical Sciences, Southern Medical University, No. 1023, South Shatai Road, Guangzhou, 510515, Guangdong, China
| | - Zhongqing Chen
- Department of Critical Care Medicine, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Qiaobing Huang
- Guangdong Provincial Key Laboratory of Shock and Microcirculation, School of Basic Medical Sciences, Southern Medical University, No. 1023, South Shatai Road, Guangzhou, 510515, Guangdong, China.
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Sharma M, Afolayan AJ. Redox Signaling and Persistent Pulmonary Hypertension of the Newborn. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 967:277-287. [PMID: 29047092 DOI: 10.1007/978-3-319-63245-2_16] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/28/2023]
Abstract
Reactive oxygen species (ROS) are redox-signaling molecules that are critically involved in regulating endothelial cell functions, host defense, aging, and cellular adaptation. Mitochondria are the major sources of ROS and important sources of redox signaling in pulmonary circulation. It is becoming increasingly evident that increased mitochondrial oxidative stress and aberrant signaling through redox-sensitive pathways play a direct causative role in the pathogenesis of many cardiopulmonary disorders including persistent pulmonary hypertension of the newborn (PPHN). This chapter highlights redox signaling in endothelial cells, antioxidant defense mechanism, cell responses to oxidative stress, and their contributions to disease pathogenesis.
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Affiliation(s)
- Megha Sharma
- Assistant Professor of Pediatrics, 999 N92nd Street, CCC suite 410, Milwaukee, WI, 53226, USA
| | - Adeleye J Afolayan
- Assistant Professor of Pediatrics, 999 N92nd Street, CCC suite 410, Milwaukee, WI, 53226, USA.
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Babooa N, Shi WJ, Chen C. Factors relating caesarean section to persistent pulmonary hypertension of the newborn. World J Pediatr 2017; 13:517-527. [PMID: 29058246 DOI: 10.1007/s12519-017-0056-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Accepted: 09/05/2016] [Indexed: 11/28/2022]
Abstract
BACKGROUND Several studies have clearly demonstrated a significantly higher incidence of persistent pulmonary hypertension of the newborn (PPHN) in neonates delivered by caesarean section (CS) compared to those delivered vaginally. The pathophysiological factors underlying the link between CS and PPHN are still poorly understood. In this review, we describe the mechanisms that could explain the association between CS delivery and subsequent PPHN, as well as potential preventive measures. DATA SOURCES A literature search was conducted by electronic scanning of databases such as PubMed and Web of Science using the key words "persistent pulmonary hypertension of the newborn", "caesarean section", "iatrogenic prematurity", "oxidative stress", "late preterm", "labor" and "vasoactive agents". RESULTS Iatrogenic prematurity, higher rates of late preterm delivery and lack of physiological changes of labor play an important role in the association between CS and PPHN. CS delivery also results in limited endogenous pulmonary vasodilator synthesis and lower levels of protective anti-oxidants in the neonates. In addition, CS delivery exposes infants to a higher risk of respiratory distress syndrome and its concomitant increase in endothelin-1 levels, which might indirectly lead to a higher risk of developing PPHN. We believe that neonates delivered by CS are exposed to a combination of these pathophysiological events, culminating in an endpoint of respiratory distress, hypoxia, acidosis, and delayed transition and thereby increased risks of PPHN. The use of antenatal corticosteroids prior to elective CS in late preterm deliveries, promoting accurate informedconsent process, delaying elective CS to 39 weeks of gestation or beyond and antenatal maternal anti-oxidant supplementation could potentially mitigate the effects of CS delivery and minimize CS-related PPHN. CONCLUSIONS The link between CS delivery and PPHN is complex. In view of the rising rates of CS worldwide, there is an urgent need to further explore the mechanisms linking CS to PPHN and experimentally test therapeutic options in order to allow effective targeted interventions.
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Affiliation(s)
- Niralee Babooa
- Department of Neonatology, Children Hospital of Fudan University, Shanghai, 201102, China
| | - Wen-Jing Shi
- Department of Neonatology, Children Hospital of Fudan University, Shanghai, 201102, China
| | - Chao Chen
- Department of Neonatology, Children Hospital of Fudan University, Shanghai, 201102, China.
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Long SL, Li YK, Xie YJ, Long ZF, Shi JF, Mo ZC. Neurite Outgrowth Inhibitor B Receptor: A Versatile Receptor with Multiple Functions and Actions. DNA Cell Biol 2017; 36:1142-1150. [PMID: 29058484 DOI: 10.1089/dna.2017.3813] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Members of the reticulon protein family are predominantly distributed within the endoplasmic reticulum. The neurite outgrowth inhibitor (Nogo) has three subtypes, including Nogo-A (200 kDa), Nogo-B (55 kDa), and Nogo-C (25 kDa). Nogo-A and Nogo-C are potent Nogos that are predominantly expressed in the central nervous system. Nogo-B, the splice variant of reticulon-4, is expressed widely in multiple human organ systems, including the liver, lung, kidney, blood vessels, and inflammatory cells. Moreover, the Nogo-B receptor (NgBR) can interact with Nogo-B and can independently affect nervous system regeneration, the chemotaxis of endothelial cells, proliferation, and apoptosis. In recent years, it has been demonstrated that NgBR plays an important role in human pathophysiological processes, including lipid metabolism, angiogenesis, N-glycosylation, cell apoptosis, chemoresistance in human hepatocellular carcinoma, and epithelial-mesenchymal transition. The pathophysiologic effects of NgBR have garnered increased attention, and the detection and enhancement of NgBR expression may be a novel approach to monitor the development and to improve the prognosis of relevant human clinical diseases.
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Affiliation(s)
- Shuang-Lian Long
- Department of Histology and Embryology, Clinical Anatomy and Reproductive Medicine Application Institute, University of South China , Hengyang, China
| | - Yu-Kun Li
- Department of Histology and Embryology, Clinical Anatomy and Reproductive Medicine Application Institute, University of South China , Hengyang, China
| | - Yuan-Jie Xie
- Department of Histology and Embryology, Clinical Anatomy and Reproductive Medicine Application Institute, University of South China , Hengyang, China
| | - Zhi-Feng Long
- Department of Histology and Embryology, Clinical Anatomy and Reproductive Medicine Application Institute, University of South China , Hengyang, China
| | - Jin-Feng Shi
- Department of Histology and Embryology, Clinical Anatomy and Reproductive Medicine Application Institute, University of South China , Hengyang, China
| | - Zhong-Cheng Mo
- Department of Histology and Embryology, Clinical Anatomy and Reproductive Medicine Application Institute, University of South China , Hengyang, China
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Caffeine ameliorates hyperoxia-induced lung injury by protecting GCH1 function in neonatal rat pups. Pediatr Res 2017; 82:483-489. [PMID: 28399119 PMCID: PMC5570644 DOI: 10.1038/pr.2017.89] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Accepted: 03/21/2017] [Indexed: 11/08/2022]
Abstract
BackgroundBronchopulmonary dysplasia (BPD) is a major morbidity in premature infants, and impaired angiogenesis is considered a major contributor to BPD. Early caffeine treatment decreases the incidence of BPD; the mechanism remains incompletely understood.MethodsSprague-Dawley rat pups exposed to normoxia or hyperoxia since birth were treated daily with either 20 mg/kg caffeine or normal saline by an intraperitoneal injection from day 2 of life. The lungs were obtained for studies at days 10 and 21.ResultsHyperoxia impaired somatic growth and lung growth in the rat pups. The impaired lung growth during hyperoxia was associated with decreased levels of cyclic AMP (cAMP) and tetrahydrobiopterin (BH4) in the lungs. Early caffeine treatment increased cAMP levels in the lungs of hyperoxia-exposed pups. Caffeine also increased the levels of phosphorylated endothelial nitric oxide synthase (eNOS) at serine1177, total and serine51 phosphorylated GTP cyclohydrolase 1 (GCH1), and BH4 levels, with improved alveolar structure and angiogenesis in hyperoxia-exposed lungs. Reduced GCH1 levels in hyperoxia were due, in part, to increased degradation by the ubiquitin-proteasome system.ConclusionOur data support the notion that early caffeine treatment can protect immature lungs from hyperoxia-induced damage by improving eNOS activity through increased BH4 bioavailability.
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Fulton DJR, Li X, Bordan Z, Haigh S, Bentley A, Chen F, Barman SA. Reactive Oxygen and Nitrogen Species in the Development of Pulmonary Hypertension. Antioxidants (Basel) 2017; 6:antiox6030054. [PMID: 28684719 PMCID: PMC5618082 DOI: 10.3390/antiox6030054] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Revised: 06/29/2017] [Accepted: 07/01/2017] [Indexed: 12/21/2022] Open
Abstract
Pulmonary arterial hypertension (PAH) is a progressive disease of the lung vasculature that involves the loss of endothelial function together with inappropriate smooth muscle cell growth, inflammation, and fibrosis. These changes underlie a progressive remodeling of blood vessels that alters flow and increases pulmonary blood pressure. Elevated pressures in the pulmonary artery imparts a chronic stress on the right ventricle which undergoes compensatory hypertrophy but eventually fails. How PAH develops remains incompletely understood and evidence for the altered production of reactive oxygen and nitrogen species (ROS, RNS respectively) in the pulmonary circulation has been well documented. There are many different types of ROS and RNS, multiple sources, and collective actions and interactions. This review summarizes past and current knowledge of the sources of ROS and RNS and how they may contribute to the loss of endothelial function and changes in smooth muscle proliferation in the pulmonary circulation.
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Affiliation(s)
- David J R Fulton
- Vascular Biology Center, Medical College of Georgia at Augusta University, Augusta, GA 30912, USA.
| | - Xueyi Li
- Vascular Biology Center, Medical College of Georgia at Augusta University, Augusta, GA 30912, USA.
| | - Zsuzsanna Bordan
- Vascular Biology Center, Medical College of Georgia at Augusta University, Augusta, GA 30912, USA.
| | - Stephen Haigh
- Vascular Biology Center, Medical College of Georgia at Augusta University, Augusta, GA 30912, USA.
| | - Austin Bentley
- Vascular Biology Center, Medical College of Georgia at Augusta University, Augusta, GA 30912, USA.
| | - Feng Chen
- Department of Forensic Medicine, Nanjing Medical University, Nanjing 211166, China.
| | - Scott A Barman
- Department of Pharmacology and Toxicology, Medical College of Georgia at Augusta University, Augusta, GA 30912, USA.
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20
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Tadokoro KS, Rana U, Jing X, Konduri GG, Miao QR, Teng RJ. Nogo-B Receptor Modulates Pulmonary Artery Smooth Muscle Cell Function in Developing Lungs. Am J Respir Cell Mol Biol 2017; 54:892-900. [PMID: 26652754 DOI: 10.1165/rcmb.2015-0068oc] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Nogo-B and its receptor (NgBR) are involved in blood vessel growth in developing lungs, but their role in pulmonary artery smooth muscle cell (PASMC) growth is unknown. We hypothesized that NgBR regulates growth of PASMCs by modulating the function of endoplasmic reticulum (ER) and formation of reactive oxygen species (ROS). In utero constriction of the ductus arteriosus created pulmonary hypertension in fetal lambs (hypertensive fetal lamb [HTFL]). PASMCs isolated 8 days after surgery were assessed for the alteration of protein levels by immunoblots and ROS formation by dihydroethidium and Cell ROX deep red fluorescence. NgBR small interfering RNA and plasmid DNA were used to manipulate NgBR levels. Proliferation and wound healing were assessed by cell counts and scratch recovery assay, respectively. Acute ER stress was induced by tunicamycin. Differences of mitogen-activated protein kinase and Akt pathway activation in HTFL versus control PASMCs were evaluated. Results showed that HTFL PASMCs had decreased NgBR levels and increased proliferation, wound healing, ER stress, and ROS formation compared with controls. Knockdown of NgBR in control PASMCs generated a phenotype similar to HTFL, and overexpression in HTFL restored the defective phenotype to control. Decreased NgBR levels were associated with increased ROS formation in HTFL PASMCs. Subsequently, scavenging ROS decreased proliferation and wound healing. Mechanistically, ROS formation decreases NgBR expression, which induces ER stress. This leads to extracellular signal-regulated kinase pathway activation and PASMC phenotype alteration. Our data suggest that decreased NgBR expression in pulmonary hypertension of the newborn contributes to increased PASMC proliferation and oxidative stress, which lead to the pathogenesis of lung injury.
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Affiliation(s)
| | - Ujala Rana
- 2 Surgery, and.,3 Pathology.,4 Children's Research Institute and Cardiovascular Research Center, and
| | - Xigang Jing
- Departments of 1 Pediatrics.,4 Children's Research Institute and Cardiovascular Research Center, and
| | - G Ganesh Konduri
- Departments of 1 Pediatrics.,4 Children's Research Institute and Cardiovascular Research Center, and.,5 Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Qing R Miao
- 2 Surgery, and.,3 Pathology.,4 Children's Research Institute and Cardiovascular Research Center, and
| | - Ru-Jeng Teng
- Departments of 1 Pediatrics.,4 Children's Research Institute and Cardiovascular Research Center, and.,5 Medical College of Wisconsin, Milwaukee, Wisconsin
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21
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Xu Y, Qian S. Techniques for Detecting Reactive Oxygen Species in Pulmonary Vasculature Redox Signaling. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 967:361-372. [DOI: 10.1007/978-3-319-63245-2_23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Zimmer J, Takahashi T, Duess JW, Hofmann AD, Puri P. Upregulation of S1P1 and Rac1 receptors in the pulmonary vasculature of nitrofen-induced congenital diaphragmatic hernia. Pediatr Surg Int 2016; 32:147-54. [PMID: 26543024 DOI: 10.1007/s00383-015-3825-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 10/09/2015] [Indexed: 11/26/2022]
Abstract
PURPOSE Sphingolipids play a crucial role in pulmonary development. The sphingosine kinase 1 (SphK1) modulates the synthesis of sphingolipid sphingosine-1-phosphate (S1P). S1P regulates cell proliferation and angiogenesis via different receptors, S1P1, S1P2 and S1P3, which all influence the expression of Ras-related C3 botulinum toxin substrate 1 (Rac1). We designed this study to test the hypothesis that the S1P/Rac1 pathway is altered in the nitrofen-induced CDH model. METHODS Pregnant rats received nitrofen or vehicle on D9. On D21, fetuses were killed and divided into nitrofen and control group (n = 12). QRT-PCR, western blotting and confocal-immunofluorescence microscopy were performed to reveal pulmonary gene and protein expression levels of SphK1, S1P1, S1P2, S1P3 and Rac1. RESULTS Pulmonary gene expression of S1P1 and Rac1 was significantly increased in the CDH group compared to controls, whereas S1P2 and S1P3 expression was decreased. These results were confirmed by western blotting and confocal microscopy. SphK1 expression was not found to be altered. CONCLUSION The increased expression of S1P1 and Rac1 in the pulmonary vasculature of nitrofen-induced CDH lungs suggests that S1P1 and Rac1 are important mediators of PH in this model.
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Affiliation(s)
- Julia Zimmer
- National Children's Research Centre, Our Lady's Children's Hospital, Crumlin, Dublin, Ireland
| | - Toshiaki Takahashi
- National Children's Research Centre, Our Lady's Children's Hospital, Crumlin, Dublin, Ireland
| | - Johannes W Duess
- National Children's Research Centre, Our Lady's Children's Hospital, Crumlin, Dublin, Ireland
- School of Medicine and Medical Science and Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Dublin, Ireland
| | - Alejandro D Hofmann
- National Children's Research Centre, Our Lady's Children's Hospital, Crumlin, Dublin, Ireland
- Department of Pediatric Surgery, Hannover Medical School, Hannover, Germany
| | - Prem Puri
- National Children's Research Centre, Our Lady's Children's Hospital, Crumlin, Dublin, Ireland.
- School of Medicine and Medical Science and Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Dublin, Ireland.
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Konduri GG, Afolayan AJ, Eis A, Pritchard KA, Teng RJ. Interaction of endothelial nitric oxide synthase with mitochondria regulates oxidative stress and function in fetal pulmonary artery endothelial cells. Am J Physiol Lung Cell Mol Physiol 2015; 309:L1009-17. [PMID: 26320159 DOI: 10.1152/ajplung.00386.2014] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Accepted: 08/04/2015] [Indexed: 11/22/2022] Open
Abstract
An increase in oxygen tension at birth is one of the key signals that initiate pulmonary vasodilation in the fetal lung. We investigated the hypothesis that targeting endothelial nitric oxide synthase (eNOS) to the mitochondrial outer membrane regulates reactive oxygen species (ROS) formation in the fetal pulmonary artery endothelial cells (PAEC) during this transition. We isolated PAEC and pulmonary arteries from 137-day gestation fetal lambs (term = 144 days). We exposed PAEC to a simulated transition from fetal to (3% O2) to normoxic (21%) or hyperoxic (95% O2) postnatal Po2 or to the nitric oxide synthase (NOS) agonist ATP. We assessed the effect of O2 and ATP on eNOS interactions with the mitochondrial outer membrane protein porin and with the chaperone hsp90. We also investigated the effect of decoy peptides that blocked eNOS interactions with porin or hsp90 on PAEC angiogenesis and vasodilator function of pulmonary arteries. Transition of fetal PAEC from 3 to 21% O2 but not to 95% O2 or exposure to ATP increased eNOS association with hsp90 and porin. Decoy peptides that blocked eNOS interactions decreased NO release, increased O2 consumption and mitochondrial ROS levels, and impaired PAEC angiogenesis. Decoy peptides also inhibited the relaxation responses of pulmonary artery rings and dilation of resistance size pulmonary arteries to ATP. The mitochondrial-antioxidant mito-ubiquinone restored the response to ATP in decoy peptide-treated pulmonary arteries. These data indicate that targeting eNOS to mitochondria decreases endothelial oxidative stress and facilitates vasodilation in fetal pulmonary circulation at birth.
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Affiliation(s)
- Girija G Konduri
- Department of Pediatrics, Cardiovascular Research Center and Children's Research Institute, Medical College of Wisconsin, Milwaukee, Wisconsin; and
| | - Adeleye J Afolayan
- Department of Pediatrics, Cardiovascular Research Center and Children's Research Institute, Medical College of Wisconsin, Milwaukee, Wisconsin; and
| | - Annie Eis
- Department of Pediatrics, Cardiovascular Research Center and Children's Research Institute, Medical College of Wisconsin, Milwaukee, Wisconsin; and
| | - Kirkwood A Pritchard
- Department of Surgery, Division of Pediatric Surgery, Cardiovascular Research Center and Children's Research Institute, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Ru-Jeng Teng
- Department of Pediatrics, Cardiovascular Research Center and Children's Research Institute, Medical College of Wisconsin, Milwaukee, Wisconsin; and
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Mukherjee S, Sriram P, Barui AK, Nethi SK, Veeriah V, Chatterjee S, Suresh KI, Patra CR. Graphene Oxides Show Angiogenic Properties. Adv Healthc Mater 2015; 4:1722-32. [PMID: 26033847 DOI: 10.1002/adhm.201500155] [Citation(s) in RCA: 135] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Revised: 05/01/2015] [Indexed: 01/04/2023]
Abstract
Angiogenesis, a process resulting in the formation of new capillaries from the pre-existing vasculature plays vital role for the development of therapeutic approaches for cancer, atherosclerosis, wound healing, and cardiovascular diseases. In this report, the synthesis, characterization, and angiogenic properties of graphene oxide (GO) and reduced graphene oxide (rGO) have been demonstrated, observed through several in vitro and in vivo angiogenesis assays. The results here demonstrate that the intracellular formation of reactive oxygen species and reactive nitrogen species as well as activation of phospho-eNOS and phospho-Akt might be the plausible mechanisms for GO and rGO induced angiogenesis. The results altogether suggest the possibilities for the development of alternative angiogenic therapeutic approach for the treatment of cardiovascular related diseases where angiogenesis plays a significant role.
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Affiliation(s)
- Sudip Mukherjee
- Biomaterials Group; CSIR-Indian Institute of Chemical Technology; Uppal Road Tarnaka Hyderabad, Telangana State 500007 India
- Academy of Scientific and Innovative Research (AcSIR); 2 Rafi Marg New Delhi 110001 India
| | - Pavithra Sriram
- Polymers and Functional Materials Division; CSIR-Indian Institute of Chemical Technology; Uppal Road Tarnaka Hyderabad, Telangana State 500007 India
| | - Ayan Kumar Barui
- Biomaterials Group; CSIR-Indian Institute of Chemical Technology; Uppal Road Tarnaka Hyderabad, Telangana State 500007 India
- Academy of Scientific and Innovative Research (AcSIR); 2 Rafi Marg New Delhi 110001 India
| | - Susheel Kumar Nethi
- Biomaterials Group; CSIR-Indian Institute of Chemical Technology; Uppal Road Tarnaka Hyderabad, Telangana State 500007 India
- Academy of Scientific and Innovative Research (AcSIR); 2 Rafi Marg New Delhi 110001 India
| | - Vimal Veeriah
- Vascular Biology Lab; Life Sciences Division; AU-KBC Research CentreAnna University; Chennai Tamil Nadu 600044 India
| | - Suvro Chatterjee
- Vascular Biology Lab; Life Sciences Division; AU-KBC Research CentreAnna University; Chennai Tamil Nadu 600044 India
- Department of Biotechnology; Anna University; 600025 Chennai India
| | - Kattimuttathu Ittara Suresh
- Polymers and Functional Materials Division; CSIR-Indian Institute of Chemical Technology; Uppal Road Tarnaka Hyderabad, Telangana State 500007 India
| | - Chitta Ranjan Patra
- Biomaterials Group; CSIR-Indian Institute of Chemical Technology; Uppal Road Tarnaka Hyderabad, Telangana State 500007 India
- Academy of Scientific and Innovative Research (AcSIR); 2 Rafi Marg New Delhi 110001 India
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Altered prostanoid metabolism contributes to impaired angiogenesis in persistent pulmonary hypertension in a fetal lamb model. Pediatr Res 2015; 77:455-62. [PMID: 25521916 PMCID: PMC4346417 DOI: 10.1038/pr.2014.209] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Accepted: 09/30/2014] [Indexed: 12/31/2022]
Abstract
BACKGROUND Persistent pulmonary hypertension of the newborn (PPHN) is associated with decreased lung angiogenesis and impaired pulmonary vasodilatation at birth. Prostanoids are important modulators of vascular tone and angiogenesis. We hypothesized that altered levels of prostacyclin (PGI₂), a potent vasodilator, and thromboxane A₂ (TXA₂), a vasoconstrictor, contribute to impaired angiogenesis of pulmonary artery endothelial cells (PAEC) in PPHN. METHODS PAEC were isolated from fetal lambs with PPHN induced by prenatal ductus arteriosus constriction or from sham operated controls. Expression and activity of PGI₂ synthase (PGIS) and TXA₂ synthase (TXAS), expression of cyclooxygenases 1 and 2 (COX-1 and COX-2), and the role of PGIS/TXAS alterations in angiogenesis were investigated in PAEC from PPHN and control lambs. RESULTS PGIS protein and activity were decreased and PGIS protein tyrosine nitration was increased in PPHN PAEC. In contrast, TXAS protein and its stimulated activity were increased in PPHN PAEC. COX-1 and COX-2 proteins were decreased in PPHN PAEC. Addition of PGI₂ improved in vitro tube formation by PPHN PAEC, whereas indomethacin decreased tube formation by control PAEC. PGIS knockdown decreased the in vitro angiogenesis in control PAEC, whereas TXAS knockdown increased the in vitro angiogenesis in PPHN PAEC. CONCLUSION Reciprocal alterations in PGI₂ and TXA₂ may contribute to impaired angiogenesis in PPHN.
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Distefano G, Sciacca P. Molecular physiopathogenetic mechanisms and development of new potential therapeutic strategies in persistent pulmonary hypertension of the newborn. Ital J Pediatr 2015; 41:6. [PMID: 25887340 PMCID: PMC4328557 DOI: 10.1186/s13052-015-0111-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2014] [Accepted: 01/13/2015] [Indexed: 12/28/2022] Open
Abstract
Persistent pulmonary hypertension of the newborn (PPHN) is a cyanogenic plurifactorial disorder characterized by failed postnatal drop of pulmonary vascular resistance and maintenance of right-to-left shunt across ductus arteriosus and foramen ovale typical of intrauterine life. The pathogenesis of PPHN is very complex and can result from functional (vasoconstriction) or structural (arteriolar remodeling, reduced pulmonary vessels density) anomalies of pulmonary circulation. Etiopathogenetic factors heterogeneity can strongly condition therapeutical results and prognosis of PPHN that is particularly severe in organic forms that are usually refractory to selective pulmonary vasodilator therapy with inhaled nitric oxide. This paper reports the more recent acquisitions on molecular physiopathogenetic mechanisms underlying functional and structural forms of PPHN and illustrates the bases for adoption of new potential treatment strategies for organic PPHN. These strategies aim to reverse pulmonary vascular remodeling in PPHN with arteriolar smooth muscle hypertrophy and stimulate pulmonary vascular and alveolar growth in PPHN associated with lung hypoplasia.In order to restore lung growth in this severe form of PPHN, attention is focused on the results of studies of mesenchymal stem cells and their therapeutical paracrine effects on bronchopulmonry dysplasia, a chronic neonatal lung disease characterized by arrested vascular and alveolar growth and development of pulmonary hypertension.
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Affiliation(s)
- Giuseppe Distefano
- Department of Pediatrics, Pediatric Cardiology Service, University of Catania, Via S.Sofia 78, Catania, 95123, Italy.
| | - Pietro Sciacca
- Department of Pediatrics, Pediatric Cardiology Service, University of Catania, Via S.Sofia 78, Catania, 95123, Italy.
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Menden H, Welak S, Cossette S, Ramchandran R, Sampath V. Lipopolysaccharide (LPS)-mediated angiopoietin-2-dependent autocrine angiogenesis is regulated by NADPH oxidase 2 (Nox2) in human pulmonary microvascular endothelial cells. J Biol Chem 2015; 290:5449-61. [PMID: 25568324 DOI: 10.1074/jbc.m114.600692] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Sepsis-mediated endothelial Angiopoeitin-2 (Ang2) signaling may contribute to microvascular remodeling in the developing lung. The mechanisms by which bacterial cell wall components such as LPS mediate Ang2 signaling in human pulmonary microvascular endothelial cells (HPMECs) remain understudied. In HPMEC, LPS-induced Ang2, Tie2, and VEGF-A protein expression was preceded by increased superoxide formation. NADPH oxidase 2 (Nox2) inhibition, but not Nox4 or Nox1 inhibition, attenuated LPS-induced superoxide formation and Ang2, Tie2, and VEGF-A expression. Nox2 silencing, but not Nox4 or Nox1 silencing, inhibited LPS-mediated inhibitor of κ-B kinase β (IKKβ) and p38 phosphorylation and nuclear translocation of NF-κB and AP-1. In HPMECs, LPS increased the number of angiogenic tube and network formations in Matrigel by >3-fold. Conditioned media from LPS-treated cells also induced angiogenic tube and network formation in the presence of Toll-like receptor 4 blockade but not in the presence of Ang2 and VEGF blockade. Nox2 inhibition or conditioned media from Nox2-silenced cells attenuated LPS-induced tube and network formation. Ang2 and VEGF-A treatment rescued angiogenesis in Nox2-silenced cells. We propose that Nox2 regulates LPS-mediated Ang2-dependent autocrine angiogenesis in HPMECs through the IKKβ/NF-κB and MAPK/AP-1 pathways.
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Affiliation(s)
| | | | | | - Ramani Ramchandran
- From the Departments of Pediatrics and Obstetrics and Gynecology, Children's Research Institute, Medical College of Wisconsin, Milwaukee, Wisconsin 53226
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Welak SR, Rentea RM, Teng RJ, Heinzerling N, Biesterveld B, Liedel JL, Pritchard KA, Fredrich KM, Gourlay DM. Intestinal NADPH oxidase 2 activity increases in a neonatal rat model of necrotizing enterocolitis. PLoS One 2014; 9:e115317. [PMID: 25517730 PMCID: PMC4269454 DOI: 10.1371/journal.pone.0115317] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2014] [Accepted: 11/21/2014] [Indexed: 12/21/2022] Open
Abstract
Necrotizing enterocolitis (NEC) is a complication of prematurity. The etiology is unknown, but is related to enteral feeding, ischemia, infection, and inflammation. Reactive oxygen species production, most notably superoxide, increases in NEC. NADPH oxidase (NOX) generates superoxide, but its activity in NEC remains unknown. We hypothesize that NOX-derived superoxide production increases in NEC. Newborn Sprague-Dawley rats were divided into control, formula-fed, formula/LPS, formula/hypoxia, and NEC (formula, hypoxia, and LPS). Intestinal homogenates were analyzed for NADPH-dependent superoxide production. Changes in superoxide levels on days 0-4 were measured. Inhibitors for nitric oxide synthase (L-NAME) and NOX2 (GP91-ds-tat) were utilized. RT-PCR for eNOS, NOX1, GP91phox expression was performed. Immunofluorescence studies estimated the co-localization of p47phox and GP91phox in control and NEC animals on D1, D2, and D4. NEC pups generated more superoxide than controls on D4, while all other groups were unchanged. NADPH-dependent superoxide production was greater in NEC on days 0, 3, and 4. GP91-ds-tat decreased superoxide production in both groups, with greater inhibition in NEC. L-NAME did not alter superoxide production. Temporally, superoxide production varied minimally in controls. In NEC, superoxide generation was decreased on day 1, but increased on days 3-4. GP91phox expression was higher in NEC on days 2 and 4. NOX1 and eNOS expression were unchanged from controls. GP91phox and p47phox had minimal co-localization in all control samples and NEC samples on D1 and D2, but had increased co-localization on D4. In conclusion, this study proves that experimentally-induced NEC increases small intestinal NOX activity. All components of NEC model are necessary for increased NOX activity. NOX2 is the major source, especially as the disease progresses.
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Affiliation(s)
- Scott R. Welak
- Division of Neonatology, Department of Pediatrics, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
- Children's Research Institute, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
- Translational Vascular Biology Program, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
- * E-mail:
| | - Rebecca M. Rentea
- Children's Research Institute, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
- Division of Pediatric Surgery, Department of Surgery, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
| | - Ru-Jeng Teng
- Division of Neonatology, Department of Pediatrics, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
- Children's Research Institute, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
- Translational Vascular Biology Program, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
| | - Nathan Heinzerling
- Children's Research Institute, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
- Division of Pediatric Surgery, Department of Surgery, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
| | - Ben Biesterveld
- Children's Research Institute, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
- Division of Pediatric Surgery, Department of Surgery, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
| | - Jennifer L. Liedel
- Division of Neonatology, Department of Pediatrics, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
- Children's Research Institute, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
- Division of Critical Care, Department of Pediatrics, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
| | - Kirkwood A. Pritchard
- Translational Vascular Biology Program, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
- Division of Pediatric Surgery, Department of Surgery, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
| | - Katherine M. Fredrich
- Translational Vascular Biology Program, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
- Division of Pediatric Surgery, Department of Surgery, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
| | - David M. Gourlay
- Children's Research Institute, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
- Translational Vascular Biology Program, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
- Division of Pediatric Surgery, Department of Surgery, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
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Berkelhamer SK, Farrow KN. Developmental regulation of antioxidant enzymes and their impact on neonatal lung disease. Antioxid Redox Signal 2014; 21:1837-48. [PMID: 24295375 PMCID: PMC4203145 DOI: 10.1089/ars.2013.5515] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
SIGNIFICANCE Deficient antioxidant defenses and compromised ability to respond to oxidative stress burden the immature lung. Routine neonatal therapies can cause increased oxidative stress with subsequent injury to the premature lung. Novel therapeutic approaches to protect the premature lung are greatly needed. RECENT ADVANCES Live cell imaging with targeted redox probes allows for the measurement of subcellular oxidative stress and for comparisons of oxidative stress across development. Comprehension of subcellular and cell-type-specific responses to oxidative stress may influence the targeting of future antioxidant therapies. CRITICAL ISSUES Challenges remain in identifying the optimal cellular targets, degree of enzyme activity, and appropriate antioxidant therapy. Further, the efficacy of delivering exogenous antioxidants to specific cell types or subcellular compartments remains under investigation. Treatment with a nonselective antioxidant could unintentionally compromise cellular function or impact cellular defense mechanisms and homeostasis. FUTURE DIRECTIONS Genetic and/or biomarker screening may identify infants at the greatest risk for oxidative lung injury and guide the use of more selective antioxidant therapies. Novel approaches to the delivery of antioxidant enzymes may allow cell type- or cellular organelle-specific therapy. Improved comprehension of the antioxidant enzyme regulation across cell type, cell compartment, gender, and developmental stage is critical to the design and optimization of therapy.
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Teng RJ, Rana U, Afolayan AJ, Zhao B, Miao QR, Konduri GG. Nogo-B receptor modulates angiogenesis response of pulmonary artery endothelial cells through eNOS coupling. Am J Respir Cell Mol Biol 2014; 51:169-77. [PMID: 24568601 DOI: 10.1165/rcmb.2013-0298oc] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Nogo-B, a reticulon-4 isoform, modulates the motility and adhesion of vascular endothelial cells after binding to its receptor, Nogo-B receptor (NgBR). Nogo-B/NgBR pathway contributes to vascular remodeling and angiogenesis, but the role of this pathway in the angiogenesis of developing lungs remains unknown. We previously reported that angiogenesis function of pulmonary artery endothelial cells (PAECs) is impaired by increased reactive oxygen species formation in a fetal lamb model of intrauterine pulmonary hypertension (IPH). Here, we report that Nogo-B/NgBR pathway is altered in IPH, and that decreased NgBR expression contributes to impaired angiogenesis in IPH. We observed a decrease in NgBR levels in lysates of whole lung or PAECs from fetal lambs with IPH compared with controls. Overexpression of NgBR in IPH PAECs rescued the in vitro angiogenesis defects and increased the phosphorylation of both Akt and endothelial nitric oxide synthase at serine(1179) as well as the levels of both manganese superoxide dismutase and GTP cyclohydrolase-1. Consistent with the phenotype of IPH PAECs, knockdown of NgBR in control PAECs decreased the levels of nitric oxide, increased the levels of reactive oxygen species, and impaired in vitro angiogenesis. Our data demonstrate that NgBR mediates PAEC angiogenesis response through the modulation of Akt/endothelial nitric oxide synthase functions, and its decreased expression is mechanistically linked to IPH-related angiogenesis defects in the developing lungs.
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Cohen SS, Powers BR, Lerch-Gaggl A, Teng RJ, Konduri GG. Impaired cerebral angiogenesis in the fetal lamb model of persistent pulmonary hypertension. Int J Dev Neurosci 2014; 38:113-8. [PMID: 25172169 DOI: 10.1016/j.ijdevneu.2014.08.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Revised: 07/22/2014] [Accepted: 08/07/2014] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Persistent pulmonary hypertension of the newborn (PPHN) is associated with increased risk of neuro-developmental impairments. Whether relative fetal hypoxia during evolution of PPHN renders the fetal brain vulnerable to perinatal brain injury remains unclear. We hypothesized that in utero ductal constriction, which induces PPHN also impairs cerebral angiogenesis. METHODS Fetal lambs with PPHN induced by prenatal ligation of the ductus arteriosus were compared to gestation matched twin controls. Freshly collected or fixed brain specimens were analyzed by immunohistochemistry, Western blot analysis, and RT-PCR. RESULTS Cortical capillary density was decreased in PPHN lambs compared to controls (Glut-1, isolectin B-4 and factor VIII, n=6, p<0.05). Hypoxia inducible factor-1α (HIF-1α) and vascular endothelial growth factor (VEGF) protein levels were decreased in cortical cell lysates of PPHN lambs. PPHN increased angiopoetin-1 (Ang-1) and tyrosine-protein kinase receptor (Tie-2) protein expression while angiopoetin-2 (Ang-2) protein levels were decreased (n=6, p<0.05). PPHN did not change mRNA levels of these proteins significantly (n=6). CONCLUSIONS PPHN decreased cortical capillary density in fetal lamb brain. PPHN decreased the expression of proteins involved in angiogenesis. These findings suggest that PPHN is associated with impaired cortical angiogenesis.
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Affiliation(s)
- Susan S Cohen
- Department of Pediatrics, Children's Research Institute, Medical College of Wisconsin, Wauwatosa, WI 53226, USA.
| | - Bethany R Powers
- Department of Pediatrics, Children's Research Institute, Medical College of Wisconsin, Wauwatosa, WI 53226, USA
| | - Alexandra Lerch-Gaggl
- Department of Pathology, Division of Pediatric Pathology, Medical College of Wisconsin, Wauwatosa, WI 53226, USA
| | - Ru-Jeng Teng
- Department of Pediatrics, Children's Research Institute, Medical College of Wisconsin, Wauwatosa, WI 53226, USA
| | - Girija Ganesh Konduri
- Department of Pediatrics, Children's Research Institute, Medical College of Wisconsin, Wauwatosa, WI 53226, USA
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Dalvi P, Wang K, Mermis J, Zeng R, Sanderson M, Johnson S, Dai Y, Sharma G, Ladner AO, Dhillon NK. HIV-1/cocaine induced oxidative stress disrupts tight junction protein-1 in human pulmonary microvascular endothelial cells: role of Ras/ERK1/2 pathway. PLoS One 2014; 9:e85246. [PMID: 24409324 PMCID: PMC3883699 DOI: 10.1371/journal.pone.0085246] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Accepted: 11/25/2013] [Indexed: 01/08/2023] Open
Abstract
Intravenous drug use (IVDU) is the major risk factor in the development of HIV-related pulmonary arterial hypertension (HRPAH); however, the pathogenesis of HRPAH in association with IVDU has yet to be characterized. Endothelial injury is considered to be an initiating factor for pulmonary vascular remodeling in animal models of PAH. Our previous study shows that simultaneous exposure to HIV-Trans-activator of transcription (Tat) and cocaine exacerbates both disruption of tight junction proteins and permeability of human pulmonary artery endothelial cells compared with either treatment alone. We here now demonstrate that this HIV-Tat and cocaine mediated endothelial dysfunction accompanies with increase in hydrogen peroxide and superoxide radicals generation and involves redox sensitive signaling pathway. Pretreatment with antioxidant cocktail attenuated the cocaine and Tat mediated disassembly of Zonula Occludens (ZO)-1 and enhancement of endothelial monolayer permeability. Furthermore, inhibition of NADPH oxidase by apocynin or siRNA-mediated knockdown of gp-91(phox) abolished the Tat/cocaine-induced reactive oxygen species (ROS) production, suggesting the NADPH oxidase mediated generation of oxidative radicals. In addition, ROS dependent activation of Ras and ERK1/2 Kinase was observed to be mediating the TJP-1 disassembly, and endothelial dysfunction in response to cocaine and Tat exposure. In conclusion, our findings demonstrate that Tat/cocaine -mediated production of ROS activate Ras/Raf/ERK1/2 pathway that contributes to disruption of tight junction protein leading to pulmonary endothelial dysfunction associated with pulmonary vascular remodeling.
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Affiliation(s)
- Pranjali Dalvi
- Division of Pulmonary and Critical Care Medicine, University of Kansas Medical Center, Kansas City, Kansas, United States of America
| | - Kun Wang
- Division of Pulmonary and Critical Care Medicine, University of Kansas Medical Center, Kansas City, Kansas, United States of America
| | - Joel Mermis
- Division of Pulmonary and Critical Care Medicine, University of Kansas Medical Center, Kansas City, Kansas, United States of America
| | - Ruoxi Zeng
- Division of Pulmonary and Critical Care Medicine, University of Kansas Medical Center, Kansas City, Kansas, United States of America
| | - Miles Sanderson
- Division of Pulmonary and Critical Care Medicine, University of Kansas Medical Center, Kansas City, Kansas, United States of America
| | - Sara Johnson
- Division of Pulmonary and Critical Care Medicine, University of Kansas Medical Center, Kansas City, Kansas, United States of America
| | - Yuqiao Dai
- Division of Pulmonary and Critical Care Medicine, University of Kansas Medical Center, Kansas City, Kansas, United States of America
| | - Garima Sharma
- Division of Pulmonary and Critical Care Medicine, University of Kansas Medical Center, Kansas City, Kansas, United States of America
| | - Amy O’Brien Ladner
- Division of Pulmonary and Critical Care Medicine, University of Kansas Medical Center, Kansas City, Kansas, United States of America
| | - Navneet K. Dhillon
- Division of Pulmonary and Critical Care Medicine, University of Kansas Medical Center, Kansas City, Kansas, United States of America
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, Kansas, United States of America
- * E-mail:
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Aggarwal S, Gross CM, Sharma S, Fineman JR, Black SM. Reactive oxygen species in pulmonary vascular remodeling. Compr Physiol 2013; 3:1011-34. [PMID: 23897679 DOI: 10.1002/cphy.c120024] [Citation(s) in RCA: 113] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The pathogenesis of pulmonary hypertension is a complex multifactorial process that involves the remodeling of pulmonary arteries. This remodeling process encompasses concentric medial thickening of small arterioles, neomuscularization of previously nonmuscular capillary-like vessels, and structural wall changes in larger pulmonary arteries. The pulmonary arterial muscularization is characterized by vascular smooth muscle cell hyperplasia and hypertrophy. In addition, in uncontrolled pulmonary hypertension, the clonal expansion of apoptosis-resistant endothelial cells leads to the formation of plexiform lesions. Based upon a large number of studies in animal models, the three major stimuli that drive the vascular remodeling process are inflammation, shear stress, and hypoxia. Although, the precise mechanisms by which these stimuli impair pulmonary vascular function and structure are unknown, reactive oxygen species (ROS)-mediated oxidative damage appears to play an important role. ROS are highly reactive due to their unpaired valence shell electron. Oxidative damage occurs when the production of ROS exceeds the quenching capacity of the antioxidant mechanisms of the cell. ROS can be produced from complexes in the cell membrane (nicotinamide adenine dinucleotide phosphate-oxidase), cellular organelles (peroxisomes and mitochondria), and in the cytoplasm (xanthine oxidase). Furthermore, low levels of tetrahydrobiopterin (BH4) and L-arginine the rate limiting cofactor and substrate for endothelial nitric oxide synthase (eNOS), can cause the uncoupling of eNOS, resulting in decreased NO production and increased ROS production. This review will focus on the ROS generation systems, scavenger antioxidants, and oxidative stress associated alterations in vascular remodeling in pulmonary hypertension.
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Affiliation(s)
- Saurabh Aggarwal
- Pulmonary Disease Program, Vascular Biology Center, Georgia Health Sciences University, Augusta, Georgia, USA
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Evidence for novel aspects of Nox4 oxidase regulation of mitochondrial function and peroxide generation in an endothelial cell model of senescence. Biochem J 2013; 452:e1-2. [PMID: 23662809 DOI: 10.1042/bj20130484] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Observations by Kozieł et al. reported in this issue of the Biochemical Journal suggest the existence of novel regulatory processes associated with new evidence for increased Nox4 (NAPDH oxidase 4) regulation of mitochondrial function in a cultured endothelial cell aging-induced senescence model. Cellular aging appears to promote a Nox4 interaction with mitochondria that disrupts complex I in the electron transport chain and increases the detection of mitochondrial H(2)O(2). Nox4 appears to maintain a highly interconnected mitochondrial network, which may influence mitochondrial fission and/or fusion mechanisms in a manner that could be a contributing factor in the loss of replicative lifespan seen in senescence.
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Increased activation of NADPH oxidase 4 in the pulmonary vasculature in experimental diaphragmatic hernia. Pediatr Surg Int 2013; 29:3-8. [PMID: 23160901 DOI: 10.1007/s00383-012-3209-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
AIM Persistent pulmonary hypertension remains a major cause of mortality and morbidity in congenital diaphragmatic hernia (CDH). NADPH oxidases (Nox) are the main source of superoxide production in vasculature. Nox4 is highly expressed in the smooth muscle and endothelial cells of the vascular wall and increased activity has been reported in the pulmonary vasculature of both experimental and human pulmonary hypertension. Peroxisome proliferator-activated receptor (PPARγ) is a key regulator of Nox4 expression. Targeted depletion of PPARγ results in pulmonary hypertension phenotype whereas activation of PPARγ attenuates pulmonary hypertension and reduces Nox4 production. The nitrofen-induced CDH model is an established model to study the pathogenesis of pulmonary hypertension in CDH. It has been previously reported that PPARγ-signaling is disrupted during late gestation and H(2)O(2) production is increased in nitrofen-induced CDH. We designed this study to investigate the hypothesis that Nox4 expression and activation is increased and vascular PPARγ is decreased in nitrofen-induced CDH. METHODS Pregnant rats were treated with either nitrofen or vehicle on gestational day 9 (D9). Fetuses were sacrificed on D21 and divided into control and CDH. RT-PCR, western blotting and confocal-immunofluorescence-double-staining were performed to determine pulmonary expression levels of PPARγ, Nox4 and Nox4-activation (p22(phox)). RESULTS There was a marked increase in medial and adventitial thickness in pulmonary arteries of all sizes in CDH compared to controls. Pulmonary Nox4 levels were significantly increased whereas PPARγ levels were decreased in nitrofen-induced CDH compared to controls. Western blotting revealed increased pulmonary protein expression of the Nox4-activating subunit p22(phox) and decreased protein expression of PPARγ in CDH compared to controls. Confocal-microscopy confirmed markedly increased pulmonary expression of the Nox4 activating subunit p22(phox) accompanied by decreased perivascular PPARγ expression in lungs of nitrofen-exposed fetuses compared to controls. CONCLUSION To our knowledge, the present study is the first to report increased Nox4 production in the pulmonary vasculature of nitrofen-induced CDH. Down-regulation of the PPARγ-signaling pathway may lead to increased superoxide production, resulting in pulmonary vascular dysfunction and contributing to pulmonary hypertension in the nitrofen-induced CDH model. PPARγ-activation inhibiting Nox4 production may therefore represent a potential therapeutic approach for the treatment of pulmonary hypertension in CDH.
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Yu M, Gong D, Lim M, Arutyunyan A, Groffen J, Heisterkamp N. Lack of bcr and abr promotes hypoxia-induced pulmonary hypertension in mice. PLoS One 2012; 7:e49756. [PMID: 23152932 PMCID: PMC3495860 DOI: 10.1371/journal.pone.0049756] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2011] [Accepted: 10/16/2012] [Indexed: 01/31/2023] Open
Abstract
BACKGROUND Bcr and Abr are GTPase activating proteins that specifically downregulate activity of the small GTPase Rac in restricted cell types in vivo. Rac1 is expressed in smooth muscle cells, a critical cell type involved in the pathogenesis of pulmonary hypertension. The molecular mechanisms that underlie hypoxia-associated pulmonary hypertension are not well-defined. METHODOLOGY/PRINCIPAL FINDINGS Bcr and abr null mutant mice were compared to wild type controls for the development of pulmonary hypertension after exposure to hypoxia. Also, pulmonary arterial smooth muscle cells from those mice were cultured in hypoxia and examined for proliferation, p38 activation and IL-6 production. Mice lacking Bcr or Abr exposed to hypoxia developed increased right ventricular pressure, hypertrophy and pulmonary vascular remodeling. Perivascular leukocyte infiltration in the lungs was increased, and under hypoxia bcr-/- and abr-/- macrophages generated more reactive oxygen species. Consistent with a contribution of inflammation and oxidative stress in pulmonary hypertension-associated vascular damage, Bcr and Abr-deficient animals showed elevated endothelial leakage after hypoxia exposure. Hypoxia-treated pulmonary arterial smooth muscle cells from Bcr- or Abr-deficient mice also proliferated faster than those of wild type mice. Moreover, activated Rac1, phosphorylated p38 and interleukin 6 were increased in these cells in the absence of Bcr or Abr. Inhibition of Rac1 activation with Z62954982, a novel Rac inhibitor, decreased proliferation, p38 phosphorylation and IL-6 levels in pulmonary arterial smooth muscle cells exposed to hypoxia. CONCLUSIONS Bcr and Abr play a critical role in down-regulating hypoxia-induced pulmonary hypertension by deactivating Rac1 and, through this, reducing both oxidative stress generated by leukocytes as well as p38 phosphorylation, IL-6 production and proliferation of pulmonary arterial smooth muscle cells.
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Affiliation(s)
- Min Yu
- Section of Molecular Carcinogenesis, Division of Hematology/Oncology, and The Saban Research Institute of Children’s Hospital, Los Angeles, California, United States of America
| | - Dapeng Gong
- Section of Molecular Carcinogenesis, Division of Hematology/Oncology, and The Saban Research Institute of Children’s Hospital, Los Angeles, California, United States of America
| | - Min Lim
- Departments of Pediatrics and Pathology, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
| | - Anna Arutyunyan
- Section of Molecular Carcinogenesis, Division of Hematology/Oncology, and The Saban Research Institute of Children’s Hospital, Los Angeles, California, United States of America
| | - John Groffen
- Section of Molecular Carcinogenesis, Division of Hematology/Oncology, and The Saban Research Institute of Children’s Hospital, Los Angeles, California, United States of America
- Departments of Pediatrics and Pathology, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
| | - Nora Heisterkamp
- Section of Molecular Carcinogenesis, Division of Hematology/Oncology, and The Saban Research Institute of Children’s Hospital, Los Angeles, California, United States of America
- Departments of Pediatrics and Pathology, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
- * E-mail:
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Teng RJ, Du J, Afolayan AJ, Eis A, Shi Y, Konduri GG. AMP kinase activation improves angiogenesis in pulmonary artery endothelial cells with in utero pulmonary hypertension. Am J Physiol Lung Cell Mol Physiol 2012; 304:L29-42. [PMID: 23103561 DOI: 10.1152/ajplung.00200.2012] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
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.
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Affiliation(s)
- Ru-Jeng Teng
- Department of Pediatrics, Medical College of Wisconsin, Milwaukee, USA.
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Afolayan AJ, Eis A, Teng RJ, Bakhutashvili I, Kaul S, Davis JM, Konduri GG. Decreases in manganese superoxide dismutase expression and activity contribute to oxidative stress in persistent pulmonary hypertension of the newborn. Am J Physiol Lung Cell Mol Physiol 2012; 303:L870-9. [PMID: 22962015 DOI: 10.1152/ajplung.00098.2012] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
A rapid increase in the synthesis and release of nitric oxide (NO) facilitates the pulmonary vasodilation that occurs during birth-related transition. Alteration of this transition in persistent pulmonary hypertension of the newborn (PPHN) is associated with impaired function of endothelial nitric oxide synthase (eNOS) and an increase in oxidative stress. We investigated the hypothesis that a decrease in expression and activity of mitochondrial localized manganese superoxide dismutase (MnSOD) in pulmonary artery endothelial cells (PAEC) increases oxidative stress and impairs eNOS function in PPHN. We isolated PAEC and pulmonary arteries from fetal lambs with PPHN induced by prenatal ductus arteriosus ligation or sham ligation (control). We investigated MnSOD expression and activity, tyrosine nitration of MnSOD, and mitochondrial O(2)(-) levels in PAEC from control and PPHN lambs. We introduced exogenous MnSOD via an adenoviral vector (ad-MnSOD) transduction into PAEC and pulmonary arteries of PPHN lambs. The effect of ad-MnSOD was investigated on: mitochondrial O(2)(-) levels, MnSOD and eNOS expression and activity, intracellular hydrogen peroxide (H(2)O(2)) levels, and catalase expression in PAEC. MnSOD mRNA and protein levels and activity were decreased and MnSOD tyrosine nitration was increased in PPHN-PAEC. ad-MnSOD transduction of PPHN-PAEC increased its activity two- to threefold, decreased mitochondrial O(2)(-) levels, and increased H(2)O(2) levels and catalase expression. ad-MnSOD transduction improved eNOS expression and function and the relaxation response of PPHN pulmonary arteries. Our observations suggest that decreased MnSOD expression and activity contribute to the endothelial dysfunction observed in PPHN.
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Affiliation(s)
- Adeleye J Afolayan
- Department of Pediatrics, Cardiovascular Research Center and Children’s Research Institute, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
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Aggarwal S, Gross C, Fineman JR, Black SM. Oxidative stress and the development of endothelial dysfunction in congenital heart disease with increased pulmonary blood flow: lessons from the neonatal lamb. Trends Cardiovasc Med 2012; 20:238-46. [PMID: 22293025 DOI: 10.1016/j.tcm.2011.11.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Congenital heart diseases associated with increased pulmonary blood flow commonly leads to the development of pulmonary hypertension. However, most patients who undergo histological evaluation have advanced pulmonary hypertension, and therefore it has been difficult to investigate aberrations in signaling cascades that precede the development of overt vascular remodeling. This review discusses the role played by both oxidative and nitrosative stress in the lung and their impact on the signaling pathways that regulate vasodilation, vessel growth, and vascular remodeling in the neonatal lung exposed to increased pulmonary blood flow.
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Affiliation(s)
- Saurabh Aggarwal
- Pulmonary Disease Program, Vascular Biology Center, Georgia Health Sciences University, Augusta, GA 30912, USA
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Wedgwood S, Lakshminrusimha S, Farrow KN, Czech L, Gugino SF, Soares F, Russell JA, Steinhorn RH. Apocynin improves oxygenation and increases eNOS in persistent pulmonary hypertension of the newborn. Am J Physiol Lung Cell Mol Physiol 2012; 302:L616-26. [PMID: 22198908 PMCID: PMC3311530 DOI: 10.1152/ajplung.00064.2011] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2011] [Accepted: 12/15/2011] [Indexed: 01/04/2023] Open
Abstract
NADPH oxidase is a major source of superoxide anions in the pulmonary arteries (PA). We previously reported that intratracheal SOD improves oxygenation and restores endothelial nitric oxide (NO) synthase (eNOS) function in lambs with persistent pulmonary hypertension of the newborn (PPHN). In this study, we determined the effects of the NADPH oxidase inhibitor apocynin on oxygenation, reactive oxygen species (ROS) levels, and NO signaling in PPHN lambs. PPHN was induced in lambs by antenatal ligation of the ductus arteriosus 9 days prior to delivery. Lambs were treated with vehicle or apocynin (3 mg/kg intratracheally) at birth and then ventilated with 100% O(2) for 24 h. A significant improvement in oxygenation was observed in apocynin-treated lambs after 24 h of ventilation. Contractility of isolated fifth-generation PA to norepinephrine was attenuated in apocynin-treated lambs. PA constrictions to NO synthase (NOS) inhibition with N-nitro-l-arginine were blunted in PPHN lambs; apocynin restored contractility to N-nitro-l-arginine, suggesting increased NOS activity. Intratracheal apocynin also enhanced PA relaxations to the eNOS activator A-23187 and to the NO donor S-nitrosyl-N-acetyl-penicillamine. Apocynin decreased the interaction between NADPH oxidase subunits p22(phox) and p47(phox) and decreased the expression of Nox2 and p22(phox) in ventilated PPHN lungs. These findings were associated with decreased superoxide and 3-nitrotyrosine levels in the PA of apocynin-treated PPHN lambs. eNOS protein expression, endothelial NO levels, and tetrahydrobiopterin-to-dihydrobiopterin ratios were significantly increased in PA from apocynin-treated lambs, although cGMP levels did not significantly increase and phosphodiesterase-5 activity did not significantly decrease. NADPH oxidase inhibition with apocynin may improve oxygenation, in part, by attenuating ROS-mediated vasoconstriction and by increasing NOS activity.
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Affiliation(s)
- Stephen Wedgwood
- Deparment of Pediatrics, Northwestern University, Chicago, Illinois, USA.
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Teng RJ, Du J, Welak S, Guan T, Eis A, Shi Y, Konduri GG. Cross talk between NADPH oxidase and autophagy in pulmonary artery endothelial cells with intrauterine persistent pulmonary hypertension. Am J Physiol Lung Cell Mol Physiol 2012; 302:L651-63. [PMID: 22245997 DOI: 10.1152/ajplung.00177.2011] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Autophagy is a process for cells to degrade proteins or entire organelles to maintain a balance in the synthesis, degradation, and subsequent recycling of cellular products. Increased reactive oxygen species formation is known to induce autophagy. We previously reported that increased NADPH oxidase (NOX) activity in pulmonary artery endothelial cells (PAEC) from fetal lambs with persistent pulmonary hypertension (PPHN) contributes to impaired angiogenesis in PPHN-PAEC compared with normal PAEC. We hypothesized that increased NOX activity in PPHN-PAEC is associated with increased autophagy, which, in turn, contributes to impaired angiogenesis in PPHN-PAEC. In the present study, we detected increased autophagy in PPHN-PAEC as shown by increased ratio of the microtubule-associated protein 1 light chain (LC3)-II to LC3-I and increased percentage of green fluorescent protein-LC3 punctate positive cells. Inhibiting autophagy by 3-methyladenine, chloroquine, and beclin-1 knockdown in PPHN-PAEC has led to decreased autophagy and increased in vitro angiogenesis. Inhibition of autophagy also decreased the association between gp91(phox) and p47(phox), NOX activity, and superoxide generation. A nonspecific antioxidant N-acetylcysteine and a NOX inhibitor apocynin decreased autophagy in PPHN-PAEC. In conclusion, autophagy may contribute to impaired angiogenesis in PPHN-PAEC through increasing NOX activity. Our results suggest that, in PPHN-PAEC, a positive feedback relationship between autophagy and NOX activity may regulate angiogenesis.
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Affiliation(s)
- Ru-Jeng Teng
- Div. of Neonatology, Dept. of Pediatrics, Medical College of Wisconsin, Wauwatosa, WI 53226, USA.
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Amanso AM, Griendling KK. Differential roles of NADPH oxidases in vascular physiology and pathophysiology. Front Biosci (Schol Ed) 2012; 4:1044-64. [PMID: 22202108 DOI: 10.2741/s317] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Reactive oxygen species (ROS) are produced by all vascular cells and regulate the major physiological functions of the vasculature. Production and removal of ROS are tightly controlled and occur in discrete subcellular locations, allowing for specific, compartmentalized signaling. Among the many sources of ROS in the vessel wall, NADPH oxidases are implicated in physiological functions such as control of vasomotor tone, regulation of extracellular matrix and phenotypic modulation of vascular smooth muscle cells. They are involved in the response to injury, whether as an oxygen sensor during hypoxia, as a regulator of protein processing, as an angiogenic stimulus, or as a mechanism of wound healing. These enzymes have also been linked to processes leading to disease development, including migration, proliferation, hypertrophy, apoptosis and autophagy. As a result, NADPH oxidases participate in atherogenesis, systemic and pulmonary hypertension and diabetic vascular disease. The role of ROS in each of these processes and diseases is complex, and a more full understanding of the sources, targets, cell-specific responses and counterbalancing mechanisms is critical for the rational development of future therapeutics.
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Affiliation(s)
- Angelica M Amanso
- Department of Medicine, Division of Cardiology, Emory University, Division of Cardiology, Atlanta, GA 30322, USA
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Postolow F, Fediuk J, Nolette N, Hinton M, Dakshinamurti S. Hypoxia and nitric oxide exposure promote apoptotic signaling in contractile pulmonary arterial smooth muscle but not in pulmonary epithelium. Pediatr Pulmonol 2011; 46:1194-208. [PMID: 21618721 DOI: 10.1002/ppul.21491] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/20/2010] [Revised: 04/08/2011] [Accepted: 04/11/2011] [Indexed: 11/11/2022]
Abstract
RATIONALE Neonatal pulmonary hypertension is characterized by hypoxia, abnormal vascular remodeling, and impaired alveolarization. Nitric oxide (NO) regulates cell replication and activation of apoptosis. Our objective was to examine cell phenotype-specific effects of hypoxia and NO exposure on cumulative apoptotic signal in neonatal pulmonary epithelial cells and arterial smooth muscle. DESIGN/METHODS Primary cultured newborn porcine pulmonary arterial myocytes and epithelial cells were grown in normoxic (21% O2) or hypoxic conditions (10% O2). Myocyte phenotype was predetermined by serum-supplementation or -deprivation. Cells were exposed to sodium nitroprusside (10(-7) -10(-4) M) or diluent for 3 days. Cell survival was estimated by MTT assay; BAX, Bcl-2, and cleaved caspase-3 by Western blot; cell cycle entry by laser scanning cytometry. RESULTS Hypoxic epithelial cells exhibited a small increase in anti-apoptotic Bcl2, and decrease in BAX. Cell survival and active caspase-3 were unchanged. Exposure to NO had no impact on epithelial apoptosis, but initiated necrosis. In contractile myocytes, pro-apoptotic BAX abundance and caspase-3 activation were increased by hypoxia, augmented by NO exposure promoting apoptosis. Hypoxia decreased BAX/Bcl-2 ratio and promoted survival of synthetic myocytes; NO increased apoptosis of normoxic synthetic myocytes, but decreased apoptosis of hypoxic synthetic myocytes. CONCLUSION The effect of NO on pulmonary apoptosis is phenotype-dependent. A cumulative apoptotic effect of hypoxia and NO in vitro exerted on contractile myocytes may lead to contraction of this subpopulation, while synthetic myocyte survival and proliferation is enhanced by hypoxia and NO. Epithelial survival is unaffected. We speculate that alveolar rarefaction reported after neonatal hypoxia may arise from growth arrest in the vascular rather than the epithelial compartment.
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Affiliation(s)
- F Postolow
- Department of Pediatrics, University of Manitoba, 715 McDermot Avenue, Winnipeg, Manitoba R3E 3P4, Canada
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Du J, Teng RJ, Guan T, Eis A, Kaul S, Konduri GG, Shi Y. Role of autophagy in angiogenesis in aortic endothelial cells. Am J Physiol Cell Physiol 2011; 302:C383-91. [PMID: 22031599 DOI: 10.1152/ajpcell.00164.2011] [Citation(s) in RCA: 135] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Angiogenesis plays critical roles in the recovery phase of ischemic heart disease and peripheral vascular disease. An increase in autophagy is protective under hypoxic and chronic ischemic conditions. In the present study we determined the role of autophagy in angiogenesis. 3-Methyladenine (3-MA) and small interfering RNA (siRNA) against ATG5 were used to inhibit autophagy induced by nutrient deprivation of cultured bovine aortic endothelial cells (BAECs). Assays of BAECs tube formation and cell migration revealed that inhibition of autophagy by 3-MA or siRNA against ATG5 reduced angiogenesis. In contrast, induction of autophagy by overexpression of ATG5 increased BAECs tube formation and migration. Additionally, inhibiting autophagy impaired vascular endothelial growth factor (VEGF)-induced angiogenesis. However, inhibition of autophagy did not alter the expression of pro-angiogenesis factors such as VEGF, platelet-derived growth factor, or integrin αV. Furthermore, autophagy increased reactive oxygen species (ROS) formation and activated AKT phosphorylation. Inhibition of autophagy significantly decreased the production of ROS and activation of AKT but not of extracellular regulated kinase, whereas overexpression of ATG5 increased cellular ROS production and AKT activation in BAECs. Inhibition of AKT activation or ROS production significantly decreased the tube formation induced by ATG5 overexpression. Here we report a novel observation that autophagy plays an important role in angiogenesis in BAECs. Induction of autophagy promotes angiogenesis while inhibition of autophagy suppresses angiogenesis, including VEGF-induced angiogenesis. ROS production and AKT activation might be important mechanisms for mediating angiogenesis induced by autophagy. Our findings indicate that targeting autophagy may provide an important new tool for treating cardiovascular disease.
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Affiliation(s)
- Jianhai Du
- Division of Pediatric Surgery, Department of Surgery, Medical College of Wisconsin, Milwaukee, 53226, USA
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Bone morphogenic protein-4 induces endothelial cell apoptosis through oxidative stress-dependent p38MAPK and JNK pathway. J Mol Cell Cardiol 2011; 52:237-44. [PMID: 22064324 DOI: 10.1016/j.yjmcc.2011.10.013] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2011] [Revised: 09/16/2011] [Accepted: 10/17/2011] [Indexed: 12/22/2022]
Abstract
The expression of bone morphogenic protein 4 (BMP4), a new pro-inflammatory marker, is increased by disturbed flow in endothelial cells (ECs). BMP4 stimulates production of reactive oxygen species (ROS) and causes endothelial cell dysfunction. The present study examined BMP4-induced apoptosis in ECs and isolated arteries from rat, mouse, and human, and the signaling pathways mediating BMP4-induced apoptosis. Apoptosis was assessed by flow cytometry to detect Annexin-V positive cells, and terminal deoxynucleotidyl transferase dUTP nick end (TUNEL) labeling. The superoxide production was measured by dihydroethidium fluorescence. BMP4 induced EC apoptosis in human mesenteric arteries, mouse aortic endothelium, rat primary ECs, and human ECs. BMP4-induced EC apoptosis was mediated through ROS production by activation of NADPH oxidase, which led to cleaved caspase-3 expression. BMP4 also induced sequential activation of p38 MAPK and JNK which was upstream of caspase 3 activation. Knockdown of BMP receptor 1A by lentiviral shRNA or NOX4 siRNA transfection inhibited BMP4-induced ROS production, p38 and JNK phosphorylation, and caspase-3 activation in ECs. JNK siRNA inhibited BMP4-induced JNK phosphorylation and caspase-3 activation. The present study delineates that BMP4 causes EC apoptosis through activation of caspase-3 in a ROS/p38MAPK/JNK-dependent signaling cascade.
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Teng RJ, Du J, Xu H, Bakhutashvili I, Eis A, Shi Y, Pritchard KA, Konduri GG. Sepiapterin improves angiogenesis of pulmonary artery endothelial cells with in utero pulmonary hypertension by recoupling endothelial nitric oxide synthase. Am J Physiol Lung Cell Mol Physiol 2011; 301:L334-45. [PMID: 21622842 PMCID: PMC3174740 DOI: 10.1152/ajplung.00316.2010] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2010] [Accepted: 05/23/2011] [Indexed: 02/07/2023] Open
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.
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Affiliation(s)
- Ru-Jeng Teng
- Division of Neonatology, Dept. of Pediatrics, Medical College of Wisconsin, Suite C410, Children Corporate Center, 999N 92nd St., Wauwatosa, WI 53226, USA.
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Farkas L, Gauldie J, Voelkel NF, Kolb M. Pulmonary Hypertension and Idiopathic Pulmonary Fibrosis. Am J Respir Cell Mol Biol 2011; 45:1-15. [DOI: 10.1165/rcmb.2010-0365tr] [Citation(s) in RCA: 149] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
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Abstract
Our understanding of, and approach to, pulmonary arterial hypertension has undergone a paradigm shift in the past decade. Once a condition thought to be dominated by increased vasoconstrictor tone and thrombosis, pulmonary arterial hypertension is now seen as a vasculopathy in which structural changes driven by excessive vascular cell growth and inflammation, with recruitment and infiltration of circulating cells, play a major role. Perturbations of a number of molecular mechanisms have been described, including pathways involving growth factors, cytokines, metabolic signaling, elastases, and proteases, that may underlie the pathogenesis of the disease. Elucidating their contribution to the pathophysiology of pulmonary arterial hypertension could offer new drug targets. The role of progenitor cells in vascular repair is also under active investigation. The right ventricular response to increased pressure load is recognized as critical to survival and the molecular mechanisms involved are attracting increasing interest. The challenge now is to integrate this new knowledge and explore how it can be used to categorize patients by molecular phenotype and tailor treatment more effectively.
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Affiliation(s)
- Ralph T. Schermuly
- Max-Planck-Institute for Heart and Lung Research, Parkstrasse 1, Bad Nauheim, 61231 Germany
| | - Hossein A. Ghofrani
- University Hospital Giessen and Marburg, University of Giessen Lung Center, Klinikstrasse 36, Giessen, 35392 Germany
| | - Martin R. Wilkins
- Division of Experimental Medicine, Centre for Pharmacology and Therapeutics, Imperial College London, Hammersmith Hospital, Du Cane Road, London, W12 0NN UK
| | - Friedrich Grimminger
- University Hospital Giessen and Marburg, University of Giessen Lung Center, Klinikstrasse 36, Giessen, 35392 Germany
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Yu L, Hales CA. Hypoxia does neither stimulate pulmonary artery endothelial cell proliferation in mice and rats with pulmonary hypertension and vascular remodeling nor in human pulmonary artery endothelial cells. J Vasc Res 2011; 48:465-75. [PMID: 21691120 DOI: 10.1159/000327005] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2010] [Accepted: 02/15/2011] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Hypoxia results in pulmonary hypertension and vascular remodeling due to induction of pulmonary artery cell proliferation. Besides pulmonary artery smooth muscle cells, pulmonary artery endothelial cells (PAECs) are also involved in the development of pulmonary hypertension, but the effect of hypoxia on PAEC proliferation has not been completely understood. METHODS We investigated PAEC proliferation in mice and rats with hypoxia-induced pulmonary hypertension and vascular remodeling as well as in human PAECs under hypoxia. RESULTS AND CONCLUSION We did not find significant PAEC proliferation in chronically hypoxic rats or mice. There was a slight decrease in proliferation in mice and rats with pulmonary hypertension and vascular remodeling. We also did not find significant human PAEC proliferation and cell cycle progression under different levels of oxygen (1, 2, 3, 5 and 10%) for one day, although the same conditions of hypoxia induced significant proliferation and cell cycle progression in pulmonary artery smooth muscle cells and pulmonary artery fibroblasts. Exposure to hypoxia for 7 days also did not increase PAEC proliferation. These results demonstrated that hypoxia alone is not a stimulus to PAEC proliferation in vivo and in vitro. The present study provides a novel role for PAECs in hypoxia-induced pulmonary hypertension and vascular remodeling.
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Affiliation(s)
- Lunyin Yu
- Pulmonary and Critical Care Unit, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA.
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Teng RJ, Wu TJ, Bisig CG, Eis A, Pritchard KA, Konduri GG. Nitrotyrosine impairs angiogenesis and uncouples eNOS activity of pulmonary artery endothelial cells isolated from developing sheep lungs. Pediatr Res 2011; 69:112-7. [PMID: 21057377 PMCID: PMC3086583 DOI: 10.1203/pdr.0b013e318204dcb8] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Infection is known to impair the growth of developing lungs. It is known that plasma free nitrotyrosine (NT) levels can reach 150 μM during sepsis. Free NT incorporates into microtubules and impairs cell function. We hypothesize that free NT perturbs the angiogenic activity of pulmonary artery endothelial cells (PAEC) in developing lungs. PAEC from fetal lamb lungs were incubated with NT (1-100 μM). We examined the effects of NT on tube formation, cell proliferation, apoptosis, and α-tubulin assembly in PAEC. We assessed superoxide anion (O2) and NO levels in PAEC during NT exposure. Effects of NT on endothelial NO synthase (eNOS) were examined with respect to eNOS-dimer formation and the association of eNOS chaperone, heat-shock-protein-90 (hsp90). NT decreased tube formation and increased apoptosis in PAEC. NT also decreased NO levels, increased NOS-dependent O2 generation, and promoted α-tubulin depolymerization. Although NT increased eNOS homodimer formation, it decreased the hsp90 association with eNOS. Our data suggest that increased NT formation during sepsis may uncouple eNOS activity and increase oxidative stress. Because NO plays an important role in angiogenesis and vasodilation, these observations suggest a mechanism for the impaired vasodilation and angiogenesis during sepsis in the developing lung.
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Affiliation(s)
- Ru-Jeng Teng
- Department of Pediatrics, Medical College of Wisconsin, Wauwatosa, Wisconsin 53226, USA
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