scholarly journals Hyperoxia disrupts vascular endothelial growth factor-nitric oxide signaling and decreases growth of endothelial colony-forming cells from preterm infants

2009 ◽  
Vol 297 (6) ◽  
pp. L1160-L1169 ◽  
Author(s):  
Hideshi Fujinaga ◽  
Christopher D. Baker ◽  
Sharon L. Ryan ◽  
Neil E. Markham ◽  
Gregory J. Seedorf ◽  
...  

Exposure of preterm infants to hyperoxia impairs vascular growth, contributing to the development of bronchopulmonary dysplasia and retinopathy of prematurity. Disruption of vascular endothelial growth factor (VEGF)-nitric oxide (NO) signaling impairs vascular growth. Endothelial progenitor cells (EPCs) may play an important role in vascular growth. Endothelial colony-forming cells (ECFCs), a type of EPC, from human preterm cord blood are more susceptible to hyperoxia-induced growth impairment than term ECFCs. Therefore, we hypothesized that hyperoxia disrupts VEGF-NO signaling and impairs growth in preterm ECFCs and that exogenous VEGF or NO preserves growth in hyperoxia. Growth kinetics of preterm cord blood-derived ECFCs (gestational ages, 27–34 wk) were assessed in room air (RA) and hyperoxia (40–50% oxygen) with or without VEGF, NO, or Nω-nitro-l-arginine. VEGF, VEGF receptor-2 (VEGFR-2), and endothelial NO synthase (eNOS) protein expression and NO production were compared. Compared with RA controls, hyperoxia significantly decreased growth, VEGFR-2 and eNOS expression, and NO production. VEGF treatment restored growth in hyperoxia to values measured in RA controls and significantly increased eNOS expression in hyperoxia. NO treatment also increased growth in hyperoxia. Nω-nitro-l-arginine treatment inhibited VEGF-augmented growth in RA and hyperoxia. We conclude that hyperoxia decreases growth and disrupts VEGF-NO signaling in human preterm ECFCs. VEGF treatment restores growth in hyperoxia by increasing NO production. NO treatment also increases growth during hyperoxia. Exogenous VEGF or NO may protect preterm ECFCs from the adverse effects of hyperoxia and preservation of ECFC function may improve outcomes of preterm infants.

Endocrinology ◽  
2011 ◽  
Vol 152 (7) ◽  
pp. 2786-2796 ◽  
Author(s):  
Jonathan T. McGuane ◽  
Julianna E. Debrah ◽  
Laura Sautina ◽  
Yagna P. R. Jarajapu ◽  
Jacqueline Novak ◽  
...  

The peptide hormone relaxin is a potent vasodilator with therapeutic potential in diseases complicated by vasoconstriction, including heart failure. However, the molecular mediators and magnitude of vasodilation may vary according to duration of exposure and artery type. The objective of these studies was to determine mechanisms of rapid (within minutes) relaxin-induced vasodilation and to examine whether relaxin dilates arteries from different animal species and vascular beds. Rat and mouse small renal, rat mesenteric, and human sc arteries were isolated, mounted in a pressure arteriograph, and treated with recombinant human relaxin (rhRLX; 1–100 ng/ml) after preconstriction with phenylephrine. Rat and mouse small renal as well as human sc arteries dilated in response to rhRLX, whereas rat mesenteric arteries did not. Endothelial removal or pretreatment with l-NG-monomethyl arginine (L-NMMA) abolished rapid relaxin-induced vasodilation; phosphatidylinositol-3-kinase (PI3K) inhibitors also prevented it. In cultured human endothelial cells, rhRLX stimulated nitric oxide (assessed using 4-amino-5-methylamino-2′7′-difluorofluorescein) as well as Akt and endothelial NO synthase (eNOS) phosphorylation by Western blotting but not increases in intracellular calcium (evaluated by fura-2). NO production was attenuated by inhibition of Gαi/o and Akt (using pertussis toxin and the allosteric inhibitor MK-2206, respectively), PI3K, and NOS. Finally, the dilatory effect of rhRLX in rat small renal arteries was unexpectedly potentiated, rather than inhibited, by pretreatment with the vascular endothelial growth factor receptor inhibitor SU5416. We conclude that relaxin rapidly dilates select arteries across a range of species. The mechanism appears to involve endothelial Gαi/o protein coupling to PI3K, Akt, and eNOS but not vascular endothelial growth factor receptor transactivation or increased calcium.


Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Jingsong Ou ◽  
Feng-Jun Chang ◽  
Zhi-Jun Ou ◽  
Xiao-Xia Hu ◽  
Jia-Yun Wu ◽  
...  

Aims: Previous clinical trials designed to stimulate coronary vascular growth (therapeutic angiogenesis) using growth factors, e.g, vascular endothelial growth factor (VEGF), in patients with coronary artery disease (CAD) were unsuccessful. Although many reasons were postulated for the failure, e.g., endothelial dysfunction, refractory response to VEGF, no consensus was achieved to explain these unsuccessful attempts. To further interrogate this conundrum, we found that high density lipoprotein from healthy subjects (nHDL) is pro-angiogenic; however, HDL from patients with CAD (pHDL) has oxidative modifications. Accordingly we postulate that this modified pHDL is proinflammatory and “switches” to an anti-angiogenic effect. To test this possibility we determined the angiogenic capacity of pHDL and of pHDL on VEGF induced-angiogenesis. Methods and Results: Human umbilical vein endothelial cells (HUVECs) were cultured; murine hearts were isolated and sectioned, and the sections were cultured under condition in which endothelial cells sprout from the sections. HUVECs and the heart sections were treated with nHDL (100 μg/ml) or pHDL (100 μg/ml) with or without VEGF stimulation. We measured proliferation, migration, tube formation of HUVECs, and number and length of sprouts from the sections. pHDL (compared to nHDL) reduced endothelial cell proliferation, migration, tube formation, and the length of the sprouts from the sections under basal conditions and also in response to VEGF (all P<0.05). To elucidate the mechanism of this negative effect of pHDL, we measured nitric oxide (NO) production, superoxide anion (O2[[Unable to Display Character: &#729;]] − ) generation, phosphorylation of endothelial nitric oxide synthase (eNOS), and Akt in HUVECs. Compared to nHDL, pHDL reduced the phosphorylation of eNOS, and Akt; and, also inhibited NO production, but increased eNOS-dependent O2[[Unable to Display Character: &#729;]] − generation. Conclusions: HDL from patients with CAD impaired VEGF-induced angiogenesis via eNOS/Akt signaling pathway. Taken together, our findings suggest that oxidatively modified HDL from patients with CAD may be a contributing factor to reasons why therapeutic angiogenesis trials failed using VEGF recombinant protein or VEGF gene therapy.


2003 ◽  
Vol 50 (1) ◽  
pp. 49-59 ◽  
Author(s):  
Hideo Kimura ◽  
Hiroyasu Esumi

Physiologically, angiogenesis is tightly regulated, or otherwise it leads to pathological processes, such as tumors, inflammatory diseases, gynecological diseases and diabetic retinopathy. The vascular endothelial growth factor (VEGF) is a potent and critical inducer of angiogenesis. The VEGF gene expression is regulated by a variety of stimuli. Hypoxia is one of the most potent inducers of the VEGF expression. The hypoxia inducible factor 1 (HIF-1) plays as a key transcription factor in hypoxia-mediated VEGF gene upregulation. Nitric oxide (NO) as well as hypoxia is reported to upregulate the VEGF gene by enhancing HIF-1 activity. The Akt/protein kinase B (PKB) pathway may be involved in NO-mediated HIF-1 activation in limited cell lines. There are some reports of negative effects of NO on HIF-1 and VEGF activity. These conflicting data of NO effects may be attributed mainly to the amount of released NO. Indeed, NO can be a positive or negative modulator of the VEGF gene under the same conditions simply by changing its amounts. The VEGF-mediated angiogenesis requires NO production from activated endothelial NO synthase (eNOS). Activation of eNOS by VEGF involves several pathways including Akt/PKB, Ca(2+)/calmodulin, and protein kinase C. The NO-mediated VEGF expression can be regulated by HIF-1 and heme oxygenase 1 (HO-1) activity, and the VEGF-mediated NO production by eNOS can be also modulated by HIF-1 and HO-1 activity, depending upon the amount of produced NO. These reciprocal relations between NO and VEGF may contribute to regulated angiogenesis in normal tissues.


2012 ◽  
Vol 32 (5) ◽  
pp. 884-895 ◽  
Author(s):  
Fabricio Simão ◽  
Aline S Pagnussat ◽  
Ji Hae Seo ◽  
Deepti Navaratna ◽  
Wendy Leung ◽  
...  

Resveratrol may be a powerful way of protecting the brain against a wide variety of stress and injury. Recently, it has been proposed that resveratrol not only reduces brain injury but also promotes recovery after stroke. But the underlying mechanisms are unclear. Here, we tested the hypothesis that resveratrol promotes angiogenesis in cerebral endothelial cells and dissected the signaling pathways involved. Treatment of cerebral endothelial cells with resveratrol promoted proliferation, migration, and tube formation in Matrigel assays. Consistent with these pro-angiogenic responses, resveratrol altered endothelial morphology resulting in cytoskeletal rearrangements of β-catenin and VE-cadherin. These effects of resveratrol were accompanied by activation of phosphoinositide 3 kinase (PI3-K)/Akt and Mitogen-Activated Protein Kinase (MAPK)/ERK signaling pathways that led to endothelial nitric oxide synthase upregulation and increased nitric oxide (NO) levels. Subsequently, elevated NO signaling increased vascular endothelial growth factor and matrix metalloproteinase levels. Sequential blockade of these signaling steps prevented resveratrol-induced angiogenesis in cerebral endothelial cells. These findings provide a mechanistic basis for the potential use of resveratrol as a candidate therapy to promote angiogenesis and neurovascular recovery after stroke.


Biochimie ◽  
2001 ◽  
Vol 83 (6) ◽  
pp. 515-522 ◽  
Author(s):  
Kyril Turpaev ◽  
Dmitry Litvinov ◽  
Vera Dubovaya ◽  
Andrey Panasyuk ◽  
Dmitry Ivanov ◽  
...  

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