Global Reach 2018: Dysfunctional Extracellular Microvesicles in Andean Highlander Males with Excessive Erythrocytosis

Author(s):  
L. Madden Brewster ◽  
Anthony R. Bain ◽  
Vinicius P. Pacheco Garcia ◽  
Hannah K Fandl ◽  
Rachel Stone ◽  
...  

High altitude-related excessive erythrocytosis (EE) is associated with increased cardiovascular risk. The experimental aim of this study was to determine the effects of microvesicles isolated from Andean highlanders with EE on endothelial cell inflammation, oxidative stress, apoptosis and nitric oxide (NO) production.Twenty-six male residents of Cerro de Pasco, Peru (4,340 m) were studied: 12 highlanders without EE (age: 40±4 yr; BMI: 26.4±1.7; Hb: 17.4±0.5 g/dL, SpO2: 86.9±1.0%) and 14 highlanders with EE (43±4 yr; 26.2±0.9; 24.4±0.4 g/dL;79.7±1.6%). Microvesicles were isolated, enumerated and collected from plasma by flow cytometry. Human umbilical vein endothelial cells were cultured and treated with microvesicles from highlanders without and with EE. Microvesicles from highlanders with EE induced significantly higher release of interleukin (IL)-6 (89.8±2.7 vs 77.1±1.9 pg/mL) and IL-8 (62.0±2.7 vs 53.3±2.2 pg/mL) compared with microvesicles from healthy highlanders. Although intracellular expression of total NF-kB p65 (65.3+6.0 vs 74.9+7.8.9 AU) was not significantly affected, microvesicles from highlanders with EE resulted in ~25% higher (P<0.05) expression of p-NF-kB p65 (173.6+14.3 vs 132.8+12.2 AU) in cells treated with microvesicles from highlanders with EE. Cell reactive oxygen species production was significantly higher (76.4.7±5.4 vs 56.7±1.7 % of control) and endothelial nitric oxide synthase (p-eNOS) activation (231.3±15.5 vs 286.6±23.0 AU) and NO production (8.3±0.6 vs 10.7±0.7 μM/L) significantly lower in cells treated with microvesicles from highlanders with vs without EE. Cell apoptotic susceptibility was not significantly affected by EE-related microvesicles.Circulating microvesicles from Andean highlanders with EE increase endothelial cell inflammation and oxidative stress and reduced NO production.

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Madden Brewster ◽  
Anthony R Bain ◽  
Vinicius P Garcia ◽  
Hannah K Fandl ◽  
Rachel Stone ◽  
...  

Background: Chronic mountain sickness, a maladaptation to high altitude (>2,500 m) characterized by excessive erythrocytosis (EE) and often severe hypoxemia, is prevalent in Andean highlanders. EE increases the risk of cardiovascular events and contributes to vascular dysfunction. Circulating extracellular microvesicles (MVs) are key mediators of cardiovascular health and disease through their interaction with the vascular endothelium. The experimental aim of this study was to determine the effects of MVs isolated from adults with EE on endothelial cell inflammation, oxidative stress, apoptosis and nitric oxide (NO) production. Methods: Twenty-six male residents of Cerro de Pasco, Peru (4,340 m) were studied: 12 highlanders without EE (healthy; age: 40±4 yr; BMI: 26.4±1.7; Hb: 17.4±0.5 g/dL, SpO 2 : 86.9±1.0%) and 14 highlanders with EE (EE: 43±4 yr; 26.2±0.9; 24.4±0.4 g/dL; 79.7±1.6%). MVs were isolated from plasma by flow cytometry. Human umbilical vein endothelial cells were cultured and treated with MVs from either healthy or EE men. Results: MVs from highlanders with EE induced significantly higher release of interleukin (IL)-6 (89.8±2.7 vs 77.1±1.9 pg/mL) and IL-8 (62.0±2.7 vs 53.3±2.2 pg/mL) compared with MVs from healthy highlanders. Although intracellular expression of total NF-κB p65 (65.3±6.0 vs 74.9±7.8.9 AU) was not significantly affected, MVs from EE men resulted in ~25% higher (P<0.05) expression of p-NF-κB p65 (Ser536; active NF-κB) (173.6±14.3 vs 132.8±12.2 AU). Additionally, cell expression of the anti-inflammatory miR-146a and miR-181b were significantly suppressed by EE MVs. Cell oxidative stress and apoptotic susceptibility were not significantly affected by MVs from EE men. However, eNOS activation (231.3±15.5 vs 286.6±23.0 AU) and NO production (8.3±0.6 vs 10.7±0.7 μM/L) were significantly lower in cells treated with MVs from EE vs healthy men. Conclusion: Increased inflammation and decreased eNOS activity and NO production renders the vascular endothelium highly susceptible to atherosclerosis and thrombosis. Andean highlanders with EE exhibit dysfunctional circulating extracellular MVs that induce a proatherogenic endothelial phenotype contributing to their increased cardiovascular risk.


2021 ◽  
Vol 22 (19) ◽  
pp. 10287
Author(s):  
Chih-Hsien Wu ◽  
Yi-Lin Chiu ◽  
Chung-Yueh Hsieh ◽  
Guo-Shiang Tsung ◽  
Lian-Shan Wu ◽  
...  

Cilostazol was suggested to be beneficial to retard in-stent atherosclerosis and prevent stent thrombosis. However, the mechanisms responsible for the beneficial effects of cilostazol are not fully understood. In this study, we attempted to verify the mechanism of the antithrombotic effect of cilostazol. Human umbilical vein endothelial cells (HUVECs) were cultured with various concentrations of cilostazol to verify its impact on endothelial cells. KLF2, silent information regulator transcript-1 (SIRT1), endothelial nitric oxide synthase (eNOS), and endothelial thrombomodulin (TM) expression levels were examined. We found cilostazol significantly activated KLF2 expression and KLF2-related endothelial function, including eNOS activation, Nitric oxide (NO) production, and TM secretion. The activation was regulated by SIRT1, which was also stimulated by cilostazol. These findings suggest that cilostazol may be capable of an antithrombotic and vasculoprotective effect in endothelial cells.


Hypertension ◽  
2020 ◽  
Vol 76 (Suppl_1) ◽  
Author(s):  
Vinicius P Garcia ◽  
Jamie G Hijmans ◽  
Kelly A Stockelman ◽  
Madden Brewster ◽  
Hannah Fandl ◽  
...  

Introduction: Endothelial nitric oxide synthase (eNOS) activity is critical to vascular health. Impaired eNOS activity and diminished NO production are common characteristics of a proatherogenic, dysfunctional endothelial phenotype that is associated with cardiovascular risk factors and disease. Extracellular microvesicles, particularly endothelial cell derived microvesicles (EMVs) represent novel mechanistic mediators of endothelial dysfunction and vascular disease. It is unknown whether eNOS suppression affects EMV number and function. We tested the following hypotheses: 1) eNOS blockade increases EMV release; and 2) EMVs derived from eNOS-suppressed cells adversely affect endothelial cell inflammation, apoptosis and NO production. Methods: Human umbilical vein endothelial cells (HUVECs) were treated with the eNOS inhibitor, L-N G -Nitroarginine methyl ester (L-NAME; 300mM) for 24 h. EMVs (CD144 + ) released into the supernatant from cells treated with L-NAME or vehicle were isolated and quantified by flow cytometry. Fresh HUVECs were then treated with either L-NAME-derived or control EMVs for 24 h. To evaluate the role of endocytosis on the endothelial effects of EMVs, HUVECs were pre-incubated (12 h) with EIPA, filipin and chlorpromazine for 2 h, and all experiments repeated. Results: EMV release was markedly higher (~100%; P<0.05) in cells treated with L-NAME compared with control (81±6 vs. 40±7 EMV/μL). L-NAME-generated EMVs induced significantly higher release of IL-6 (38.4±5.1 vs. 21.0±1.9 pg/mL) and IL-8 (38.9±3.5 vs. 27.2±3.1 pg/mL) as well as greater active NF-κB p65 (Ser-536) (9.7±0.7 vs. 6.1±0.6 AU) expression than control EMVs. The expression of activated-caspase-3 was significantly higher in the cells treated with L-NAME (9.5±1.1 vs. 6.4±0.4 AU). Total eNOS (97.1±8.2 vs. 157.5±15.6 AU), activated eNOS (4.9±1.2 vs. 9.1±1.3 AU) and NO production (5.0±0.8 vs. 7.0±0.6 μmol/L) were significantly lower in endothelial cells treated with EMVs from eNOS suppressed cells. Endocytosis blockers mitigated the deleterious endothelial effects of EMVs. Conclusion: eNOS-suppression increases EMV release. Moreover, EMVs from eNOS-suppressed cells increase endothelial cell inflammation and apoptosis and decrease NO production.


2002 ◽  
Vol 282 (6) ◽  
pp. H2066-H2075 ◽  
Author(s):  
Guohao Dai ◽  
Olga Tsukurov ◽  
Michael Chen ◽  
Jonathan P. Gertler ◽  
Roger D. Kamm

External pneumatic compression (EPC) is effective in preventing deep vein thrombosis (DVT) and is thought to alter endothelial thromboresistant properties. We investigated the effect of EPC on changes in nitric oxide (NO), a critical mediator in the regulation of vasomotor and platelet function. An in vitro cell culture system was developed to simulate flow and vessel collapse conditions under EPC. Human umbilical vein endothelial cells were cultured and subjected to tube compression (C), pulsatile flow (F), or a combination of the two (FC). NO production and endothelial nitric oxide synthase (eNOS) mRNA expression were measured. The data demonstrate that in the F and FC groups, there is a rapid release of NO followed by a sustained increase. NO production levels in the F and FC groups were almost identical, whereas the C group produced the same low amount of NO as the control group. Conditions F and FC also upregulate eNOS mRNA expression by a factor of 2.08 ± 0.25 and 2.11 ± 0.21, respectively, at 6 h. Experiments with different modes of EPC show that NO production and eNOS mRNA expression respond to different time cycles of compression. These results implicate enhanced NO release as a potentially important factor in the prevention of DVT.


2018 ◽  
Vol 115 (18) ◽  
pp. 4672-4677 ◽  
Author(s):  
Seung-Hyun Lee ◽  
Jaesung Seo ◽  
Soo-Yeon Park ◽  
Mi-Hyeon Jeong ◽  
Hyo-Kyoung Choi ◽  
...  

Programmed cell death 5 (PDCD5) has been associated with human cancers as a regulator of cell death; however, the role of PDCD5 in the endothelium has not been revealed. Thus, we investigated whether PDCD5 regulates protein kinase B (PKB/AKT)-endothelial nitric oxide synthase (eNOS)–dependent signal transduction in the endothelium and affects atherosclerosis. Endothelial-specific PDCD5 knockout mice showed significantly reduced vascular remodeling compared with wild-type (WT) mice after partial carotid ligation. WT PDCD5 competitively inhibited interaction between histone deacetylase 3 (HDAC3) and AKT, but PDCD5L6R, an HDAC3-binding–deficient mutant, did not. Knockdown of PDCD5 accelerated HDAC3–AKT interaction, AKT and eNOS phosphorylation, and nitric oxide (NO) production in human umbilical vein endothelial cells. Moreover, we found that serum PDCD5 levels reflect endothelial NO production and are correlated with diabetes mellitus, high-density lipoprotein cholesterol, and coronary calcium in human samples obtained from the cardiovascular high-risk cohort. Therefore, we conclude that PDCD5 is associated with endothelial dysfunction and may be a novel therapeutic target in atherosclerosis.


Hypertension ◽  
2015 ◽  
Vol 66 (suppl_1) ◽  
Author(s):  
Lakeisha C Tillery ◽  
Evangeline D Motley-Johnson

Protease-activated receptors (PARs) have been shown to regulate endothelial nitric oxide synthase (eNOS) through the activation of specific sites on the enzyme. It has been established that phosphorylation of eNOS-Ser-1177 leads to the production of the potent vasodilator nitric oxide (NO), and is associated with PAR-2 activation; while phosphorylation of eNOS-Thr-495 decreases NO production, and is coupled to PAR-1 activation. In this study, we demonstrate a differential regulation of the eNOS/NO pathway by the PARs using primary adult human coronary artery endothelial cells (HCAEC). Thrombin and the PAR-1 activating peptide, TFLLR, which are known to phosphorylate eNOS-Thr-495 in bovine and human umbilical vein endothelial cells, phosphorylated eNOS-Ser-1177 in HCAECs, and increased NO production. The PAR-1 responses were blocked using SCH-79797, a PAR-1 inhibitor, and L-NAME was used to inhibit NO production. A PAR-2 specific ligand, SLIGRL, which has been shown to phosphorylate eNOS-Ser-1177 in bovine and human umbilical vein endothelial cells, primarily regulated eNOS-Thr-495 phosphorylation and suppressed NO production in the HCAECs. PAR-3, known for its non-signaling potential, was activated by TFRGAP, a PAR-3 mimicking peptide, and only induced phosphorylation of eNOS-Thr-495 with no effect on NO production. In addition, we confirmed that PAR-mediated eNOS-Ser-1177 phosphorylation was calcium-dependent using the calcium chelator, BAPTA, and eNOS-Thr-495 phosphorylation was mediated via Rho kinase using the ROCK inhibitor, Y-27632. These data suggest a vascular bed specific differential coupling of PARs to the signaling pathways that regulate eNOS and NO production that may be responsible for the modulation of endothelial function associated with cardiovascular disease.


2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
DengKe Yin ◽  
ZhuQing Liu ◽  
DaiYin Peng ◽  
Ye Yang ◽  
XiangDong Gao ◽  
...  

Tao-Hong-Si-Wu decoction (TSD) is a famous traditional Chinese medicine (TCM) and widely used for ischemic disease in China. TSD medicated serum was prepared after oral administration of TSD (1.6 g/kg) twice a day for 3 days in rats. TSD medicated serum induced human umbilical vein endothelial cells (HUVECs) proliferation, VEGF secretion, and nitric oxide (NO) production. These promoted effects of TSD were partly inhibited by treatment with PI3K inhibitor (LY294002) or eNOS inhibitor (L-NAME), respectively, and completely inhibited by treatment with LY294002 and L-NAME simultaneously. Western blot analysis findings further indicated that TSD medicated serum upregulated p-Akt and p-eNOS expressions, which were significantly inhibited by LY294002 or L-NAME and completely inhibited by both LY294002 and L-NAME; these results indicated that TSD medicated serum induced HUVECs VEGF expression via PI3K/Akt-eNOS signaling. TSD medicated serum contains hydroxysafflor yellow A, ferulic acid, and ligustilide detected by UPLC with standards, so these effect of TSD medicated serum may be associated with these three active compounds absorbed in serum.


2019 ◽  
Vol 242 (2) ◽  
pp. 159-172 ◽  
Author(s):  
Jiean Xu ◽  
Qiuhua Yang ◽  
Xiaoyu Zhang ◽  
Zhiping Liu ◽  
Yapeng Cao ◽  
...  

Insulin resistance-related disorders are associated with endothelial dysfunction. Accumulating evidence has suggested a role for adenosine signaling in the regulation of endothelial function. Here, we identified a crucial role of endothelial adenosine kinase (ADK) in the regulation of insulin resistance. Feeding mice with a high-fat diet (HFD) markedly enhanced the expression of endothelial Adk. Ablation of endothelial Adk in HFD-fed mice improved glucose tolerance and insulin sensitivity and decreased hepatic steatosis, adipose inflammation and adiposity, which were associated with improved arteriole vasodilation, decreased inflammation and increased adipose angiogenesis. Mechanistically, ADK inhibition or knockdown in human umbilical vein endothelial cells (HUVECs) elevated intracellular adenosine level and increased endothelial nitric oxide synthase (NOS3) activity, resulting in an increase in nitric oxide (NO) production. Antagonism of adenosine receptor A2b abolished ADK-knockdown-enhanced NOS3 expression in HUVECs. Additionally, increased phosphorylation of NOS3 in ADK-knockdown HUVECs was regulated by an adenosine receptor-independent mechanism. These data suggest that Adk-deficiency-elevated intracellular adenosine in endothelial cells ameliorates diet-induced insulin resistance and metabolic disorders, and this is associated with an enhancement of NO production caused by increased NOS3 expression and activation. Therefore, ADK is a potential target for the prevention and treatment of metabolic disorders associated with insulin resistance.


2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Azizah Ugusman ◽  
Zaiton Zakaria ◽  
Kien Hui Chua ◽  
Nor Anita Megat Mohd Nordin ◽  
Zaleha Abdullah Mahdy

Nitric oxide (NO), produced by endothelial nitric oxide synthase (eNOS), is a major antiatherogenic factor in the blood vessel. Oxidative stress plays an important role in the pathogenesis of various cardiovascular diseases, including atherosclerosis. Decreased availability of endothelial NO promotes the progression of endothelial dysfunction and atherosclerosis. Rutin is a flavonoid with multiple cardiovascular protective effects. This study aimed to investigate the effects of rutin on eNOS and NO production in cultured human umbilical vein endothelial cells (HUVEC). HUVEC were divided into four groups: control; oxidative stress induction with 180 μM H2O2; treatment with 300 μM rutin; and concomitant induction with rutin and H2O2for 24 hours. HUVEC treated with rutin produced higher amount of NO compared to control (P<0.01). In the oxidative stress-induced HUVEC, rutin successfully induced cells’ NO production (P<0.01). Rutin promoted NO production in HUVEC by inducing eNOS gene expression (P<0.05), eNOS protein synthesis (P<0.01), and eNOS activity (P<0.05). Treatment with rutin also led to increased gene and protein expression of basic fibroblast growth factor (bFGF) in HUVEC. Therefore, upregulation of eNOS expression by rutin may be mediated by bFGF. The results showed that rutin may improve endothelial function by augmenting NO production in human endothelial cells.


2016 ◽  
Vol 27 (25) ◽  
pp. 3972-3979 ◽  
Author(s):  
Xiangquan Kong ◽  
Liang Chen ◽  
Peng Ye ◽  
Zhimei Wang ◽  
Junjie Zhang ◽  
...  

Hyaluronan (HA) in the endothelial glycocalyx serves as a mechanotransducer for high-shear-stress–stimulated endothelial nitric oxide synthase (eNOS) phosphorylation and nitric oxide (NO) production. Low shear stress (LSS) has been shown to contribute to endothelial inflammation and atherosclerosis by impairing the barrier and mechanotransduction properties of the glycocalyx. Here we focus on the possible role of hyaluronidase 2 (HYAL2) in LSS-induced glycocalyx impairment and the resulting alterations in eNOS phosphorylation and NO production in human umbilical vein endothelial cells (HUVECs). We show that LSS strongly activates HYAL2 to degrade HA in the glycocalyx. The dephosphorylation of eNOS–Ser-633 under LSS was triggered after HA degradation by hyaluronidase and prevented by repairing the glycocalyx with high–molecular weight hyaluronan. Knocking down HYAL2 in HUVECs protected against HA degradation in the glycocalyx by inhibiting the expression and activity of HYAL2 and further blocked the dephosphorylation of eNOS–Ser-633 and the decrease in NO production in response to LSS. The LSS-induced dephosphorylation of PKA was completely abrogated in HYAL2 siRNA–transfected HUVECs. The LSS-induced dephosphorylation of eNOS–Ser-633 was also reversed by the PKA activator 8-Br-cAMP. We thus suggest that LSS inhibits eNOS–Ser-633 phosphorylation and, at least partially, NO production by activating HYAL2 to degrade HA in the glycocalyx.


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