scholarly journals Endothelial Dysfunction Driven by Hypoxia—The Influence of Oxygen Deficiency on NO Bioavailability

Biomolecules ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 982
Author(s):  
Anna Janaszak-Jasiecka ◽  
Anna Siekierzycka ◽  
Agata Płoska ◽  
Iwona T. Dobrucki ◽  
Leszek Kalinowski
Keyword(s):  
Oxidative Stress ◽  
Nitric Oxide ◽  
Endothelial Cells ◽  
Endothelial Dysfunction ◽  
Cell Activation ◽  
Oxygen Deficiency ◽  
Endothelial Cell Activation ◽  
Enos Uncoupling ◽  
No Bioavailability ◽  
Endothelial Nitric Oxide

Cardiovascular diseases (CVDs) are the leading cause of death worldwide. The initial stage of CVDs is characterized by endothelial dysfunction, defined as the limited bioavailability of nitric oxide (NO). Thus, any factors that interfere with the synthesis or metabolism of NO in endothelial cells are involved in CVD pathogenesis. It is well established that hypoxia is both the triggering factor as well as the accompanying factor in cardiovascular disease, and diminished tissue oxygen levels have been reported to influence endothelial NO bioavailability. In endothelial cells, NO is produced by endothelial nitric oxide synthase (eNOS) from L-Arg, with tetrahydrobiopterin (BH4) as an essential cofactor. Here, we discuss the mechanisms by which hypoxia affects NO bioavailability, including regulation of eNOS expression and activity. What is particularly important is the fact that hypoxia contributes to the depletion of cofactor BH4 and deficiency of substrate L-Arg, and thus elicits eNOS uncoupling—a state in which the enzyme produces superoxide instead of NO. eNOS uncoupling and the resulting oxidative stress is the major driver of endothelial dysfunction and atherogenesis. Moreover, hypoxia induces impairment in mitochondrial respiration and endothelial cell activation; thus, oxidative stress and inflammation, along with the hypoxic response, contribute to the development of endothelial dysfunction.

scholarly journals Mulberry Extract Attenuates Endothelial Dysfunction through the Regulation of Uncoupling Endothelial Nitric Oxide Synthase in High Fat Diet Rats

Nutrients ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 978 ◽  
Author(s):  
Geum-Hwa Lee ◽  
The-Hiep Hoang ◽  
Eun-Soo Jung ◽  
Su-Jin Jung ◽  
Soo-Wan Chae ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Endothelial Cells ◽  
Endothelial Dysfunction ◽  
Nitric Oxide Synthase ◽  
High Fat Diet ◽  
Endothelial Nitric Oxide Synthase ◽  
High Fat ◽  
Enos Uncoupling ◽  
Oxide Synthase ◽  
Endothelial Nitric Oxide

Dyslipidemia is associated with endothelial dysfunction, which is linked to nitric oxide (NO) biology. The coupling of endothelial NO synthase with cofactors is a major step for NO release. This study is aimed to investigate the vascular pharmacology effects of mulberry in rat thoracic aorta and human vascular endothelial cells. In vitro, we investigated the protective effects of the mulberry extract and its main component cyanidin-3-rutinoside (C-3-R), against oxidized low-density lipoprotein (ox-LDL)-induced endothelial nitric oxide synthase (eNOS) uncoupling. Whereas ox-LDL significantly decreased NO levels in endothelial cells, mulberry extract, and C-3-R significantly recovered NO levels and phospho-eNOS Thr495 and Ser1177 expression. In vivo, mulberry was administered to 60% of high-fat diet (w/w)-fed Sprague Dawley (SD) rats for six weeks, in which endothelium-dependent relaxations were significantly improved in organ bath studies and isometric tension recordings. Consistently, aortic expressions of phospho-eNOS and nitrotyrosine were increased. Mulberry also raised serum NO levels, increased phosphorylation of eNOS, and reduced nitrotyrosine and intracellular reactive oxygen species (ROS) in aortas, showing that mulberry preserves endothelium-dependent relaxation in aortas from high-fat diet rats. We suggest that this effect is mediated through enhanced NO bioavailability, in which the regulation of ROS and its reduced eNOS uncoupling are involved.

scholarly journals Endothelial PPAR-γ provides vascular protection from IL-1β-induced oxidative stress

2016 ◽  
Vol 310 (1) ◽  
pp. H39-H48 ◽  
Author(s):  
Masashi Mukohda ◽  
Madeliene Stump ◽  
Pimonrat Ketsawatsomkron ◽  
Chunyan Hu ◽  
Frederick W. Quelle ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Nitric Oxide ◽  
Endothelial Dysfunction ◽  
Nitric Oxide Synthase ◽  
Transgenic Mice ◽  
Stress Responses ◽  
Endothelial Nitric Oxide Synthase ◽  
Ppar Γ ◽  
Oxide Synthase ◽  
Endothelial Nitric Oxide

Loss of peroxisome proliferator-activated receptor (PPAR)-γ function in the vascular endothelium enhances atherosclerosis and NF-κB target gene expression in high-fat diet-fed apolipoprotein E-deficient mice. The mechanisms by which endothelial PPAR-γ regulates inflammatory responses and protects against atherosclerosis remain unclear. To assess functional interactions between PPAR-γ and inflammation, we used a model of IL-1β-induced aortic dysfunction in transgenic mice with endothelium-specific overexpression of either wild-type (E-WT) or dominant negative PPAR-γ (E-V290M). IL-1β dose dependently decreased IκB-α, increased phospho-p65, and increased luciferase activity in the aorta of NF-κB-LUC transgenic mice. IL-1β also dose dependently reduced endothelial-dependent relaxation by ACh. The loss of ACh responsiveness was partially improved by pretreatment of the vessels with the PPAR-γ agonist rosiglitazone or in E-WT. Conversely, IL-1β-induced endothelial dysfunction was worsened in the aorta from E-V290M mice. Although IL-1β increased the expression of NF-κB target genes, NF-κB p65 inhibitor did not alleviate endothelial dysfunction induced by IL-1β. Tempol, a SOD mimetic, partially restored ACh responsiveness in the IL-1β-treated aorta. Notably, tempol only modestly improved protection in the E-WT aorta but had an increased protective effect in the E-V290M aorta compared with the aorta from nontransgenic mice, suggesting that PPAR-γ-mediated protection involves antioxidant effects. IL-1β increased ROS and decreased the phospho-endothelial nitric oxide synthase (Ser1177)-to-endothelial nitric oxide synthase ratio in the nontransgenic aorta. These effects were completely abolished in the aorta with endothelial overexpression of WT PPAR-γ but were worsened in the aorta with E-V290M even in the absence of IL-1β. We conclude that PPAR-γ protects against IL-1β-mediated endothelial dysfunction through a reduction of oxidative stress responses but not by blunting IL-1β-mediated NF-κB activity.

Tackling endothelial dysfunction by modulating NOS uncoupling: new insights into its pathogenesis and therapeutic possibilities

2012 ◽  
Vol 302 (5) ◽  
pp. E481-E495 ◽  
Author(s):  
Rinrada Kietadisorn ◽  
Rio P. Juni ◽  
An L. Moens
Keyword(s):  
Nitric Oxide ◽  
Endothelial Dysfunction ◽  
Endothelial Function ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Therapeutic Interventions ◽  
Enos Uncoupling ◽  
Underlying Causes ◽  
Oxide Synthase ◽  
Endothelial Nitric Oxide

Endothelial nitric oxide synthase (eNOS) serves as a critical enzyme in maintaining vascular pressure by producing nitric oxide (NO); hence, it has a crucial role in the regulation of endothelial function. The bioavailability of eNOS-derived NO is crucial for this function and might be affected at multiple levels. Uncoupling of eNOS, with subsequently less NO and more superoxide generation, is one of the major underlying causes of endothelial dysfunction found in atherosclerosis, diabetes, hypertension, cigarette smoking, hyperhomocysteinemia, and ischemia/reperfusion injury. Therefore, modulating eNOS uncoupling by stabilizing eNOS activity, enhancing its substrate, cofactors, and transcription, and reversing uncoupled eNOS are attractive therapeutic approaches to improve endothelial function. This review provides an extensive overview of the important role of eNOS uncoupling in the pathogenesis of endothelial dysfunction and the potential therapeutic interventions to modulate eNOS for tackling endothelial dysfunction.

Abstract 15999: The Divergent Effects of Exercise Training After Myocardial Infarction or Pressure Overload Depend Critically on Endothelial Nitric Oxide Synthase

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Yanti Octavia ◽  
Elza v Deel ◽  
Monique d Waard ◽  
Martine d Boer ◽  
An Moens ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Nitric Oxide ◽  
Exercise Training ◽  
Endothelial Nitric Oxide Synthase ◽  
Pressure Overload ◽  
Beneficial Effects ◽  
Enhanced Chemiluminescence ◽  
Enos Uncoupling ◽  
Oxide Synthase ◽  
Endothelial Nitric Oxide

AIMS: Beneficial effects of aerobic exercise training are widely recognized. However, previously we discovered that the positive effects of exercise depend on the underlying cause of cardiac failure. Here we tested the hypothesis that endothelial nitric oxide synthase (eNOS) dependent regulation of the balance between nitric oxide and superoxide (O2•-) is critically involved in determining the effects of exercise. METHODS: Mice were exposed to 8 weeks of voluntary wheel running exercise training (EX) or sedentary housing (SED) immediately following myocardial infarction (MI), pressure overload from a transverse aortic constriction (TAC), or sham (SH) surgery. Subsequently, left ventricular (LV) ejection fraction (EF) was measured by echocardiography and Picrosirius Red staining was performed to measure collagen content. Additionally, total and NOS-dependent LV O2•- were measured using lucigenin-enhanced chemiluminescence without or with NOS inhibitor, L-NAME. eNOS uncoupling was evaluated by determining eNOS monomer dimer protein ratio and peroxynitrite (ONOO-) levels were measured through luminol-enhanced chemiluminescence. RESULTS: Cardiac dysfunction and fibrosis were ameliorated by exercise in MI but not in TAC mice (Table 1). MI and TAC both increased LV O2•- levels. Strikingly, EX diminished O2•- generation in MI, but exacerbated O2•- generation in TAC (Table 1). Furthermore, the EX-induced increase in O2•- levels in TAC were largely NOS-dependent. Accordingly, MI and TAC-induced eNOS uncoupling was normalized by EX in MI but aggravated in TAC mice (Table 1). Similarly, increased ONOO- levels following MI and TAC were diminished by EX in MI, but exacerbated by EX in TAC (Table 1). CONCLUSIONS: EX reduces eNOS-mediated cardiac oxidative stress in MI. In contrast, beneficial effects of EX are lacking in cardiac pressure-overload following TAC, due to EX-induced aggravation of ONOO- formation, eNOS uncoupling and concomitant oxidative stress.

Abstract 66: The Role of the Viral Nef Protein as a Mediator of HIV-1--Induced Endothelial Dysfunction

2012 ◽  
Vol 111 (suppl_1) ◽  
Author(s):  
Ting Wang
Keyword(s):  
Cardiovascular Disease ◽  
T Cells ◽  
Endothelial Cells ◽  
Endothelial Cell ◽  
Endothelial Dysfunction ◽  
Binding Site ◽  
Cell Activation ◽  
Endothelial Activation ◽  
Endothelial Cell Activation ◽  
Hiv 1

With the prevalence of antiviral therapy in the developed world, many HIV-1-infected people die of diseases other than AIDS. One of the emerging major causes is cardiovascular disease, leading to the prediction that the majority of HIV-1 patients are expected to develop cardiovascular complications. Endothelial dysfunction is thought to be a key event in the development of cardiovascular diseases, particularly atherosclerosis. Assays testing the effect of HIV-1 on endothelial activation shows that direct contact with HIV-1 infected T cells enhance endothelial cell activation to a greater extent than HIV-1 alone, suggesting an intracellular HIV-1 protein is responsible for endothelial activation. The HIV-1 viral protein Nef, which is responsible for T cell activation and maintenance of high viral loads in vivo , has been shown to mediate its own transfer to bystander cells. We demonstrate here for the first time that Nef induces nanotube-like conduits connecting T cells and endothelial cells. We also show that Nef is transferred from T cells to endothelial cells via these nanotubes, and is necessary and sufficient for endothelial cell activation. Moreover, we show that SIV-infected macaques exhibit endothelial Nef expression in coronary arteries. Nef expression in endothelial cells causes endothelial apoptosis, ROS and MCP-1 production. Interestingly, a Nef SH3 binding site mutant abolishes Nef-induced apoptosis and ROS formation and reduces MCP-1 production in endothelial cells, suggesting that the Nef SH3 binding site is critical for Nef effects on endothelial cells. Nef induces apoptosis of endothelial cells through an NADPH oxidase- and ROS-dependent mechanism, while Nef-induced MCP-1 production is NF-kB dependent. Taken together, these data suggest that Nef can mediate its transfer from T cells to endothelial cells through nanotubes to enhance endothelial dysfunction.Thus, Nef is a promising new therapeutic target for reducing the risk for cardiovascular disease in the HIV-1 positive population.

scholarly journals Lipoic acid antagonizes paraquat-induced vascular endothelial dysfunction by suppressing mitochondrial reactive oxidative stress

2019 ◽  
Vol 8 (6) ◽  
pp. 918-927 ◽  
Author(s):  
Li Pang ◽  
Ping Deng ◽  
Yi-dan Liang ◽  
Jing-yu Qian ◽  
Li-Chuan Wu ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Nitric Oxide ◽  
Endothelial Cells ◽  
Endothelial Dysfunction ◽  
Lipoic Acid ◽  
Microvascular Endothelial Cells ◽  
Ros Generation ◽  
Protective Effects ◽  
Migration Ability ◽  
Microvascular Endothelial

Abstract Paraquat (PQ) is a widely used herbicide in the agricultural field. The lack of an effective antidote is the significant cause of high mortality in PQ poisoning. Here, we investigate the antagonistic effects of alpha lipoic acid (α-LA), a naturally existing antioxidant, on PQ toxicity in human microvascular endothelial cells (HMEC-1). All the doses of 250, 500 and 1000 μM α-LA significantly inhibited 1000 μM PQ-induced cytotoxicity in HMEC-1 cells. α-LA pretreatment remarkably diminished the damage to cell migration ability, recovered the declined levels of the vasodilator factor nitric oxide (NO), elevated the expression level of endothelial nitric oxide synthases (eNOS), and inhibited the upregulated expression of vasoconstrictor factor endothelin-1 (ET-1). Moreover, α-LA pretreatment inhibited reactive oxygen species (ROS) generation, suppressed the damage to the mitochondrial membrane potential (ΔΨm) and mitigated the inhibition of adenosine triphosphate (ATP) production in HMEC-1 cells. These results suggested that α-LA could alleviate PQ-induced endothelial dysfunction by suppressing oxidative stress. In summary, our present study provides novel insight into the protective effects and pharmacological potential of α-LA against PQ toxicity in microvascular endothelial cells.

Role of endothelial nitric oxide synthase in endothelial activation: insights from eNOS knockout endothelial cells

2004 ◽  
Vol 286 (5) ◽  
pp. C1195-C1202 ◽  
Author(s):  
Peter J. Kuhlencordt ◽  
Eva Rosel ◽  
Robert E. Gerszten ◽  
Manuel Morales-Ruiz ◽  
David Dombkowski ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Cell Adhesion ◽  
Endothelial Cell ◽  
Adhesion Molecule ◽  
Cell Adhesion Molecule ◽  
Cell Activation ◽  
Cell Interactions ◽  
Wild Type ◽  
Endothelial Cell Activation ◽  
Endothelial Nitric Oxide

The objective of this study was to determine whether absence of endothelial nitric oxide synthase (eNOS) affects the expression of cell surface adhesion molecules in endothelial cells. Murine lung endothelial cells (MLECs) were prepared by immunomagnetic bead selection from wild-type and eNOS knockout mice. Wild-type cells expressed eNOS, but eNOS knockout cells did not. Expression of neuronal NOS and inducible NOS was not detectable in cells of either genotype. Upon stimulation, confluent wild-type MLECs produced significant amounts of NO compared with Nω-monomethyl-l-arginine-treated wild-type cells. eNOS knockout and wild-type cells showed no difference in the expression of E-selectin, P-selectin, intracellular adhesion molecule-1, and vascular cell adhesion molecule-1 as measured by flow cytometry on the surface of platelet endothelial cell adhesion molecule-1 (PECAM-1/CD31)-positive cells. Both eNOS knockout and wild-type cells displayed the characteristics of resting endothelium. Adhesion studies in a parallel plate laminar flow chamber showed no difference in leukocyte-endothelial cell interactions between the two genotypes. Cytokine treatment induced endothelial cell adhesion molecule expression and increased leukocyte-endothelial cell interactions in both genotypes. We conclude that in resting murine endothelial cells, absence of endothelial production of NO by itself does not initiate endothelial cell activation or promote leukocyte-endothelial cell interactions. We propose that eNOS derived NO does not chronically suppress endothelial cell activation in an autocrine fashion but serves to counterbalance signals that mediate activation.

scholarly journals The Role of Endothelial Microparticle in Coronary Heart Disease as The Complications of Diabetes Mellitus

2019 ◽  
Vol 4 (1) ◽  
pp. 31-39
Author(s):  
Eka Fithra Elfi ◽  
Yose Ramda Ilhami ◽  
Eryati Darwin
Keyword(s):  
Nitric Oxide ◽  
Diabetes Mellitus ◽  
Coronary Heart Disease ◽  
Heart Disease ◽  
Endothelial Dysfunction ◽  
Cell Activation ◽  
Inflammatory Factors ◽  
Endothelial Cell Activation ◽  
Complications Of Diabetes

  Coronary heart disease (CHD) is caused by obstruction of coronary blood flow due to endothelial dysfunction triggered by various genetic and non-genetic risk factors such as hyperlipidemia, hypertension, hyperglycemia and obesity. Endothelial cell activation due to hyperglycaemia in diabetes mellitus induces production of pro-inflammatory factors that damage the cell membrane triggering the formation of membrane particles called microparticles. Endothe-lial microparticles contain proteins including endothelial nitric oxide synthase (eNOS) which plays a role in the production of nitric oxide (NO). To determine the role of microparticles in the occurrence of coro-nary heart disease in diabetes mellitus due to endothelial dysfunction, a study was conducted by comparing the levels of eNOS and NO in DM patients who had CHD with DM patients who had no CHD. Blood samples from 20 DM patients who had CHD and 20 DM patients who had no CHD of the outpatients in Cardiology Department and Inter-nal Medicine department of regional public hospital were included in this study. All patients were fulfilled inclusion and exclusion criteria and diagnosed by the appropriate specialist. The eNOS and NO lev-els were measured using the ELISA method. The results of this study show that eNOS levels in the group of DM patients who had CHD (21,292±12,415 ng/ml) were significantly lower (p <0.05) than those in the group of DM patients who had no CHD (29,721±11,952 ng/ml). Nitric oxide levels in DM patients who had CHD (0,053±0,021 nmol/ μl) were not statistically different to the levels in DM patients who had no CHD (0,047±0,032 nmol/μl). From the results of this study we concluded that endothelial microparticle protein eNOS plays a role in the occurrence of CHD due to the complications of diabetes mellitus 

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