scholarly journals VE-PTP inhibition elicits eNOS phosphorylation to blunt endothelial dysfunction and hypertension in diabetes

2020 ◽  
Author(s):  
Mauro Siragusa ◽  
Alberto Fernando Oliveira Justo ◽  
Pedro Felipe Malacarne ◽  
Anna Strano ◽  
Akshay Buch ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Endothelial Cells ◽  
Shear Stress ◽  
Endothelial Dysfunction ◽  
Vascular Reactivity ◽  
Therapeutic Option ◽  
Diabetic Patients ◽  
No Production ◽  
Vascular Endothelial ◽  
Enos Activity

Abstract Aims Receptor-type vascular endothelial protein tyrosine phosphatase (VE-PTP) dephosphorylates Tie-2 as well as CD31, VE-cadherin, and vascular endothelial growth factor receptor 2 (VEGFR2). The latter form a signal transduction complex that mediates the endothelial cell response to shear stress, including the activation of the endothelial nitric oxide (NO) synthase (eNOS). As VE-PTP expression is increased in diabetes, we investigated the consequences of VE-PTP inhibition (using AKB-9778) on blood pressure in diabetic patients and the role of VE-PTP in the regulation of eNOS activity and vascular reactivity. Methods and results In diabetic patients AKB-9778 significantly lowered systolic and diastolic blood pressure. This could be linked to elevated NO production, as AKB increased NO generation by cultured endothelial cells and elicited the NOS inhibitor-sensitive relaxation of endothelium-intact rings of mouse aorta. At the molecular level, VE-PTP inhibition increased the phosphorylation of eNOS on Tyr81 and Ser1177 (human sequence). The PIEZO1 activator Yoda1, which was used to mimic the response to shear stress, also increased eNOS Tyr81 phosphorylation, an effect that was enhanced by VE-PTP inhibition. Two kinases, i.e. abelson-tyrosine protein kinase (ABL)1 and Src were identified as eNOS Tyr81 kinases as their inhibition and down-regulation significantly reduced the basal and Yoda1-induced tyrosine phosphorylation and activity of eNOS. VE-PTP, on the other hand, formed a complex with eNOS in endothelial cells and directly dephosphorylated eNOS Tyr81 in vitro. Finally, phosphorylation of eNOS on Tyr80 (murine sequence) was found to be reduced in diabetic mice and diabetes-induced endothelial dysfunction (isolated aortic rings) was blunted by VE-PTP inhibition. Conclusions VE-PTP inhibition enhances eNOS activity to improve endothelial function and decrease blood pressure indirectly, through the activation of Tie-2 and the CD31/VE-cadherin/VEGFR2 complex, and directly by dephosphorylating eNOS Tyr81. VE-PTP inhibition, therefore, represents an attractive novel therapeutic option for diabetes-induced endothelial dysfunction and hypertension.

Laminar Flow on Endothelial Cells Suppresses eNOS O-GlcNAcylation to Promote eNOS Activity

2021 ◽  
Author(s):  
Sarah Basehore ◽  
Samantha Bohlman ◽  
Callie Weber ◽  
Swathi Swaminathan ◽  
Yuji Zhang ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Endothelial Cells ◽  
Shear Stress ◽  
Laminar Flow ◽  
No Production ◽  
Disturbed Flow ◽  
Enos Activity ◽  
Enos Phosphorylation ◽  
Steady Laminar ◽  
In Cells

Rationale: In diabetic animals as well as high glucose cell culture conditions, endothelial nitric oxide synthase (eNOS) is heavily O-GlcNAcylated, which inhibits its phosphorylation and nitric oxide (NO) production. It is unknown, however, whether varied blood flow conditions, which affect eNOS phosphorylation, modulate eNOS activity via O-GlcNAcylation-dependent mechanisms. Objective: The goal of this study was to test if steady laminar flow, but not oscillating disturbed flow, decreases eNOS O-GlcNAcylation, thereby elevating eNOS phosphorylation and NO production. Methods and Results: Human umbilical vein endothelial cells (HUVEC) were exposed to either laminar flow (20 dynes/cm2 shear stress) or oscillating disturbed flow (4{plus minus}6 dynes/cm2 shear stress) for 24 hours in a cone-and-plate device. eNOS O-GlcNAcylation was almost completely abolished in cells exposed to steady laminar but not oscillating disturbed flow. Interestingly, there was no change in protein level or activity of key O-GlcNAcylation enzymes (OGT, OGA, or GFAT). Instead, metabolomics data suggest that steady laminar flow decreases glycolysis and hexosamine biosynthetic pathway (HBP) activity, thereby reducing UDP-GlcNAc pool size and consequent O-GlcNAcylation. Inhibition of glycolysis via 2-deoxy-2-glucose (2-DG) in cells exposed to disturbed flow efficiently decreased eNOS O-GlcNAcylation, thereby increasing eNOS phosphorylation and NO production. Finally, we detected significantly higher O-GlcNAcylated proteins in endothelium of the inner aortic arch in mice, suggesting that disturbed flow increases protein O-GlcNAcylation in vivo. Conclusions: Our data demonstrate that steady laminar but not oscillating disturbed flow decreases eNOS O-GlcNAcylation by limiting glycolysis and UDP-GlcNAc substrate availability, thus enhancing eNOS phosphorylation and NO production. This research shows for the first time that O-GlcNAcylation is regulated by mechanical stimuli, relates flow-induced glycolytic reductions to macrovascular disease, and highlights targeting HBP metabolic enzymes in endothelial cells as a novel therapeutic strategy to restore eNOS activity and prevent EC dysfunction in cardiovascular disease.

scholarly journals Effect of Hyperglycemia on Epcs Function and Regenerative Ability

2020 ◽  
Author(s):  
Hadeel Khalil Hendawi ◽  
Dina Nehad Awartani ◽  
Aya Ghoul ◽  
Isra Marei
Keyword(s):  
Endothelial Cells ◽  
Shear Stress ◽  
Barrier Function ◽  
Vascular Endothelial Cells ◽  
Vascular Dysfunction ◽  
Vascular Complications ◽  
Cardiovascular Complications ◽  
Diabetic Patients ◽  
Vascular Endothelial ◽  
Cell Functions

Diabetes induced hyperglycemia increases the risk of cardiovascular complications as it impacts vascular endothelial cells causing vascular dysfunction. Endothelial progenitor cells (EPCs) have been suggested to participate in the repair of vascular endothelial cells once they are impacted by hyperglycemia in diabetic patients. This research aims to test the EPC subtype blood outgrowth endothelial cells (BOECs) and their ability to survive and function under chronic hyperglycemic conditions. For that, we studied BOECs viability, response to shear stress, angiogenesis ability, and barrier function under normoglycemic (5.5mM) and hyperglycemic (25mM) conditions. The results have shown significant effects of chronic hyperglycemic conditions on cell proliferation (n=3, p<0.05), and migration (n=3, p<0.05) which were decreased when compared to control. Cells responses to shear stress were not affected under these conditions. There was a trend towards an increase in permeability as indicated by barrier function assays. The decrease in those endothelial cell functions might impact the repair mechanisms needed in diabetic patients to protect from vascular complications. Further investigations are required to establish therapeutic targets to improve EPCs repair function.

scholarly journals High glucose-induced IKK-Hsp-90 interaction contributes to endothelial dysfunction

2009 ◽  
Vol 296 (1) ◽  
pp. C182-C192 ◽  
Author(s):  
Sumathy Mohan ◽  
Ryszard Konopinski ◽  
Bo Yan ◽  
Victoria E. Centonze ◽  
Mohan Natarajan
Keyword(s):  
Nitric Oxide ◽  
Endothelial Cells ◽  
Endothelial Dysfunction ◽  
High Glucose ◽  
Vascular Endothelial Cells ◽  
Heat Shock Protein 90 ◽  
No Production ◽  
Enos Activity ◽  
Hsp 90 ◽  
Endothelial Nitric Oxide

A decline in the bioavailability of nitric oxide (NO) that causes endothelial dysfunction is a hallmark of diabetes. The availability of NO to the vasculature is regulated by endothelial nitric oxide synthase (eNOS) activity and the involvement of heat shock protein-90 (Hsp-90) in the regulation of eNOS activity has been demonstrated. Hsp-90 has been shown to interact with upstream kinases [inhibitor κB kinases (IKK)α, β, and γ] in nonvascular cells. In this study, we have investigated the interaction of Hsp-90-IKKβ in endothelial cells under conditions of high glucose (HG) as a possible mechanism that diminishes Hsp-90-eNOS interaction, which could contribute to reduced bioavailability of NO. We report for the first time that IKKβ interacts with Hsp-90, and this interaction is augmented by HG in vascular endothelial cells. HG also augments transcriptional (3.5 ± 0.65-fold) and translational (1.97 ± 0.17-fold) expression as well as the catalytic activity of IKKβ (2.45 ± 0.4-fold). Both IKKβ and eNOS could be coimmunoprecipitated with Hsp-90. Inhibition of Hsp-90 with geldanamycin (2 μM) or Radicicol (20 μM) mitigated (0.45 ± 0.04-fold and 0.93 ± 0.16-fold, respectively) HG induced-IKKβ activity (2.5 ± 0.42-fold). Blocking of IKKβ expression by IKK inhibitor II (15 μM wedelolactone) or small interferring RNA (siRNA) improved Hsp-90-eNOS interaction and NO production under conditions of HG. These results illuminate a possible mechanism for the declining eNOS activity reported under conditions of HG.

Clinopodium chinense Attenuates Palmitic Acid-Induced Vascular Endothelial Inflammation and Insulin Resistance through TLR4-Mediated NF-κB and MAPK Pathways

2019 ◽  
Vol 47 (01) ◽  
pp. 97-117 ◽  
Author(s):  
Xiaoji Shi ◽  
Shanshan Wang ◽  
Huiling Luan ◽  
Dina Tuerhong ◽  
Yining Lin ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Insulin Resistance ◽  
Endothelial Cells ◽  
Endothelial Dysfunction ◽  
Palmitic Acid ◽  
Vascular Endothelium ◽  
Interleukin 1 ◽  
No Production ◽  
Vascular Endothelial ◽  
Mapk Pathways

Elevated palmitic acid (PA) levels are associated with the development of inflammation, insulin resistance (IR) and endothelial dysfunction. Clinopodium chinense (Benth.) O. Kuntze has been shown to lower blood glucose and attenuate high glucose-induced vascular endothelial cells injury. In the present study we investigated the effects of ethyl acetate extract of C. chinense (CCE) on PA-induced inflammation and IR in the vascular endothelium and its molecular mechanism. We found that CCE significantly inhibited PA-induced toll-like receptor 4 (TLR4) expression in human umbilical vein endothelial cells (HUVECs). Consequently, this led to the inhibition of the following downstream adapted proteins myeloid differentiation primary response gene 88, Toll/interleukin-1 receptor domain-containing adaptor-inducing interferon-[Formula: see text] and TNF receptor-associated factor 6. Moreover, CCE inhibited the phosphorylation of Ikappa B kinase [Formula: see text], nuclear factor kappa-B (NF-[Formula: see text]B), c-Jun N-terminal kinase, extracellular regulated protein kinases, p38-mitogen-activated protein kinase (MAPK) and subsequently suppressed the release of tumor necrosis factor-[Formula: see text], interleukin-1[Formula: see text] (IL-1[Formula: see text]) and IL-6. CCE also inhibited IRS-1 serine phosphorylation and ameliorated insulin-mediated tyrosine phosphorylation of IRS-1. Moreover, CCE restored serine/threonine kinase and endothelial nitric oxide synthase (eNOS) activation and thus increased insulin-mediated nitric oxide (NO) production in PA-treated HUVECs. This led to reverse insulin mediated endothelium-dependent relaxation, eNOS phosphorylation and NO production in PA-treated rat thoracic aortas. These results suggest that CCE can significantly inhibit the inflammatory response and alleviate impaired insulin signaling in the vascular endothelium by suppressing TLR4-mediated NF-[Formula: see text]B and MAPK pathways. Therefore, CCE can be considered as a potential therapeutic candidate for endothelial dysfunction associated with IR and diabetes.

Abstract 1420: Mitochondrial Arginase II Constrains Endothelial NOS Activity

Circulation ◽  
2007 ◽  
Vol 116 (suppl_16) ◽  
Author(s):  
Hyun Kyo LIM ◽  
Hyun Kyoung Lim ◽  
Sungwoo Ryoo ◽  
Alex Benjo ◽  
Karl Shuleri ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Vascular Endothelial Cells ◽  
Vascular Stiffness ◽  
No Production ◽  
Vascular Endothelial ◽  
Knock Out ◽  
Enos Activity ◽  
Arginase Ii ◽  
Oxide Synthase ◽  
Endothelial Nitric Oxide

Background: Arginase II is known as a major isoenzyme in the vascular endothelial cells of humans and other species and modulates endothelial nitric oxide synthase (eNOS) activity by regulating intracellular L-arginine bioavailability. We tested under hypothesis that subcellular localization of arginase II is confined to the mitochondria and mitochondrial arginase II deficiency reciprocally regulates the vascular endothelial NO production, contributes to improve endothelial dysfunction and decrease vascular stiffness. Methods and Results: Western blot, immunocytochem with Mitotracker and immunoEM confirmed that arginase II is confined predominantly but not exclusively to the mitochondria. Arginase activity was significantly reduced, whereas NO production was significantly increased in aorta and isolated endothelial cells from arginase II knock out (ArgII−/−) compared to WT mice. Vasorelaxation to acetylcholine (ACh) was markedly enhanced and vasoconstriction to phenylephrine (PE) was impaired in ArgII−/− rings. Furthermore inhibition of eNOS by N G -nitro-L-arginine methyl ester (L-NAME) impaired ACh response and restored PE response. The baseline pulse wave velocity was significantly decreased in ArgII −/− mice (3.30 ± 0.21 vs. 3.64 ± 0.12 m/s, ArgII −/− vs. WT, *p<0.01), while 14 days of L-NAME treatment resulted in significant increase the PWV in both WT (4.23 ± 0.11 m/s, **p<0.001) and ArgII −/− mice (4.36 ± 0.20 m/s, **p<0.001). Conclusions: These data suggest that arginase II is predominantly confined to the mitochondria and this mitochondrial arginase II regulate the NO production, vascular endothelial function, and vascular stiffness by modulating eNOS activity.

Abstract 169: Impaired Shear Stress-induced Endothelial Nitric Oxide Production in High Glucose Condition is Restored by Inhibiton via NADPH Consumption by Polyol Pathway Activation

2015 ◽  
Vol 35 (suppl_1) ◽  
Author(s):  
Tomio Umemoto ◽  
Masatoshi Kuroki ◽  
Hiroto Ueba ◽  
Masanobu Kawakami ◽  
Hideo Fujita ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Endothelial Cells ◽  
Shear Stress ◽  
Endothelial Dysfunction ◽  
High Glucose ◽  
Polyol Pathway ◽  
No Production ◽  
Pathway Activation ◽  
High Glucose Condition ◽  
Glucose Condition

Endothelial dysfunction leading to cardiovascular disease risk involves a decrease in nitric oxide (NO) production. In physiological conditions shear stress is a potent stimulation of endothelium-derived NO production and flow mediated NO production is regulated by the activation of endothelial NO synthase (eNOS). In endothelial cells, eNOS, aldose reductase (AR), a rate limiting enzyme of polyol pathway, and glutathione reductase (GR) share a NADPH as an obligate cofactor. In diabetec condition intracellular polyol pathway is activated and this may decrease shear stress-induced endothelial NO production and increase intracellular oxidative stress via inhibition of eNOS and GR by NADPH consumption. Therefore we investigated whethter AR inhibitor epalrestat improved endothelial NO production under high glucose condition to elucidate the mechanism of endothelial dysfunction in diabetes. We incubated human umbilical vein endothelial cells (HUVECs) in normal (5mM) and high (30mM) glucose condition for 72 hours, with or without epralrestat, or 100U/ml superoxide dismutase (SOD), respectively. After exchange of medium for Krebs’ buffer, HUVECs were exposed to 12dyne/cm2 steady laminar fluid shear stress for 5 minutes. NO release from HUVECs was measured as NO2 using a NOx analyzing HPLC system by Griess reaction. Next we harvested the cells in lysis buffer and analyzed phosphorylation of Akt (shear induced intracellular signal transduction) and eNOS by western blotting, and measured intracellular 8-OHdG and ratio of NADPH/NADP. In high glucose condition NO2 was decreased and 8-OHdG increased compared to low glucose. NO2 was restored and 8-OHdG was reduced by epalrestat significantly (p<0.01, p<0.05, respectively, vs. high glucose condition). In SOD-treated HUVECs, NO2 was not restored (n.s. vs. high glucose condition) despite of complete reduction of 8-OHdG (p<0.01). Both Akt and eNOS phosphorylation by shear stress was affected neither by high glucose, epalrestat nor SOD. Intracellular NADPH/NADP ratio was decreased in high glucose condition, but this reduction was restored by epalrestat. These results showed that polyol pathway activation plays a key role in endothelial NO production under high glucose condition via a cofactor NADPH.

scholarly journals Disturbed Flow Induces Endothelial Dysfunction by Regulating Thioredoxin-Interacting Protein-Mediated Mitochondrial Energy Homoeostasis

2021 ◽  
Author(s):  
Yongshun Wang ◽  
Jingjin Liu ◽  
Xin Sun ◽  
Jie Yuan ◽  
Huadong Liu ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Shear Stress ◽  
Endothelial Dysfunction ◽  
Energy Homeostasis ◽  
Glucose Utilization ◽  
Shear Stresses ◽  
No Production ◽  
Disturbed Flow ◽  
Structural Wall

Abstract Endothelial cells are highly sensitive to hemodynamic shear stresses, which act in the blood flow’s direction on the blood vessel’s luminal surface. Endothelial cells on that surface, thusly, are exposed to various physiological and pathological stimuli, such as disturbed flow-induced shear stress, which may exert effects on adaptive vascular diameter or structural wall remodeling. Here we showed that human endothelial cells exposed to disturbed flow exhibited increased levels of thioredoxin-interactive protein (TXNIP) in vitro. On the other hand, deletion of human endothelial TXNIP increased capillary formation, NO production and mitochondrial function, as well as lessened oxidative stress response and endothelial cell inflammation. Additional beneficial impacts from TXNIP deletion were also seen in a glucose utilization study, as reflected by augmented glucose uptake, lactate secretion and extracellular acidification rate. Taken together, our results suggested that TXNIP is a key component involved in mediating shear stress-induced inflammation, energy homeostasis, and glucose utilization, ultimately establishing it as a potentially novel endothelial dysfunction regulator.

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