Abstract 410: Mitochondrial Uncoupling with CCCP Reverses Acute Hyperglycemia Induced Endothelial Dysfunction in Human Arterioles

Background : Acute hyperglycemia (HG) impairs endothelial function, which may be related to hyperpolarization of the inner mitochondrial membrane and excessive production of mitochondrial superoxide (ROS). Mitochondrial uncoupling agents could potentially reverse endothelial dysfunction due to HG in intact human arterioles. Methods : Human adipose arterioles were incubated in either euglycemic (NG, 5mM) or hyperglycemic (HG, 33mM) buffer for 4 hours. Vessels were then exposed to increasing doses of acetylcholine (ACh) in the presence and absence of NADPH oxidase inhibitor gp91ds-tat or CCCP, (100 nM), a mitochondrial membrane uncoupling agent. Vascular superoxide levels were also measured after incubation with NG and HG using a chemiluminescent probe (L-012) in the absence and presence of 1 and 2 above. Results : ACh-induced vasodilation was impaired by HG vs. NG control (P<0.001). This impairment was modestly reversed by gp91 ds-tat (P< 0.001), but endothelial function was completely restored to the level observed under euglycemic conditions by CCCP (P=0.008 vs. HG, P>0.90 vs. NG). Endothelium-dependent vasodilation in HG vessels was greater after CCCP compared to gp91ds-tat (P<0.001). L-NAME inhibited all dilation to ACh indicating endothelium-dependence (data not shown). HG induced an increase in superoxide relative to NG (P<0.001), which was similarly suppressed by gp91ds-tat (P = 0.001) and CCCP (P=0.002). Conclusion : HG-induced endothelial dysfunction is reversed with partial uncoupling of mitochondrial oxidative phosphorylation. Mitochondrial uncoupling more than NADPH oxidase blockade improves endothelial dysfunction due to HG.

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The H+ Transporter SLC4A11: Roles in Metabolism, Oxidative Stress and Mitochondrial Uncoupling

Cells ◽

10.3390/cells11020197 ◽

2022 ◽

Vol 11 (2) ◽

pp. 197

Author(s):

Joseph A. Bonanno ◽

Raji Shyam ◽

Moonjung Choi ◽

Diego G. Ogando

Keyword(s):

Oxidative Stress ◽

Mitochondrial Membrane ◽

Inner Mitochondrial Membrane ◽

Mitochondrial Uncoupling ◽

Mitochondrial Oxidative Stress ◽

Antioxidant Genes ◽

Knock Out ◽

Bicarbonate Transporter ◽

Mitochondrial Superoxide ◽

Transporter Family

Solute-linked cotransporter, SLC4A11, a member of the bicarbonate transporter family, is an electrogenic H+ transporter activated by NH3 and alkaline pH. Although SLC4A11 does not transport bicarbonate, it shares many properties with other members of the SLC4 family. SLC4A11 mutations can lead to corneal endothelial dystrophy and hearing deficits that are recapitulated in SLC4A11 knock-out mice. SLC4A11, at the inner mitochondrial membrane, facilitates glutamine catabolism and suppresses the production of mitochondrial superoxide by providing ammonia-sensitive H+ uncoupling that reduces glutamine-driven mitochondrial membrane potential hyperpolarization. Mitochondrial oxidative stress in SLC4A11 KO also triggers dysfunctional autophagy and lysosomes, as well as ER stress. SLC4A11 expression is induced by oxidative stress through the transcription factor NRF2, the master regulator of antioxidant genes. Outside of the corneal endothelium, SLC4A11’s function has been demonstrated in cochlear fibrocytes, salivary glands, and kidneys, but is largely unexplored overall. Increased SLC4A11 expression is a component of some “glutamine-addicted” cancers, and is possibly linked to cells and tissues that rely on glutamine catabolism.

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Diabetes induces pulmonary artery endothelial dysfunction by NADPH oxidase induction

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.90354.2008 ◽

2008 ◽

Vol 295 (5) ◽

pp. L727-L732 ◽

Cited By ~ 43

Author(s):

Jose G. Lopez-Lopez ◽

Javier Moral-Sanz ◽

Giovanna Frazziano ◽

Maria J. Gomez-Villalobos ◽

Jorge Flores-Hernandez ◽

...

Keyword(s):

Endothelial Dysfunction ◽

Nadph Oxidase ◽

Pulmonary Arteries ◽

Diabetic Rats ◽

Oxidase Inhibitor ◽

No Synthase ◽

Superoxide Production ◽

Regulatory Subunit ◽

Sprague Dawley ◽

Relaxant Response

Recent data suggest that diabetes is a risk factor for pulmonary hypertension. The aim of the present study was to analyze whether diabetes induces endothelial dysfunction in pulmonary arteries and the mechanisms involved. Male Sprague-Dawley rats were randomly divided into a control (saline) and a diabetic group (70 mg/kg−1 streptozotocin). After 6 wk, intrapulmonary arteries were mounted for isometric tension recording, and endothelial function was tested by the relaxant response to acetylcholine. Protein expression and localization were measured by Western blot and immunohistochemistry and superoxide production by dihydroethidium staining. Pulmonary arteries from diabetic rats showed impaired relaxant response to acetylcholine and reduced vasoconstrictor response to the nitric oxide (NO) synthase inhibitor l-NAME, whereas the response to nitroprusside and the expression of endothelial NO synthase remained unchanged. Endothelial dysfunction was reversed by addition of superoxide dismutase or the NADPH oxidase inhibitor apocynin. An increase in superoxide production and increased expression of the NADPH oxidase regulatory subunit p47phox were also found in pulmonary arteries from diabetic rats. In conclusion, the pulmonary circulation is a target for diabetes-induced endothelial dysfunction via enhanced NADPH oxidase-derived superoxide production.

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Abstract 2523: Azelnidipine Enhances Beneficial Effects of Olmesartan on Left Ventricular Remodeling During the Development of Hypertension-induced Heart Failure

Circulation ◽

10.1161/circ.116.suppl_16.ii_557-a ◽

2007 ◽

Vol 116 (suppl_16) ◽

Author(s):

Xian Wu Cheng ◽

Kenji Okumura ◽

Kohzo Nagata ◽

Aiko Inoue ◽

Jie Zhang ◽

...

Keyword(s):

Heart Failure ◽

Nadph Oxidase ◽

Ventricular Remodeling ◽

Left Ventricular Remodeling ◽

Left Ventricular ◽

Oxidase Inhibitor ◽

List Type ◽

Superoxide Anion Production ◽

Cardioprotective Effects

Objective: This work was undertaken to investigate the comparative effect of angiotensin II type 1 receptor blocker (ARB) and a combination of ARB and calcium channel blocker (CCB) on left ventricular (LV) remodeling during the development of hypertensive heart failure (H-HF). Methods and Results: We treated 8% salt-loaded Dahl salt-sensitive hypertensive rats (n = 10 for each group) with vehicle, hydralazine (5 mg/kg/d), olmesartan (OLM, 5 mg/kg/d), or combined OLM and azelnidipine (AZE, 2mg/kg/d) for 8 weeks. The rats fed 0.3% salt served as age-matched controls. The abundance of Cat mRNAs and proteins were localized in cardiac myocytes (CMCs), and Cat-dependent activities were increased by 4.1-fold in the LV of H-HF rats (n = 8, P< 0.001) and were reduced by OLM treatment. OLM suppressed the elastic lamina degradation concomitant with decreased local Cat S expression in intracoronary smooth muscle cells (SMCs) and restored the balance of elastin to collagen in the LV tissue of H-HF rats (H-HF 4.6 ± 0.9% vs. OLM 15.5 ± 2.1% elastin content/collagen content (%), n = 6, P< 0.0±1; control 22±2.1%). OLM suppressed not only macrophage infiltration but also levels of NADPH oxidase components (p22 phox , gp91 phox , and p47 phox ) concomitant with decreased NADPH activity and O2- production in LV tissues of H-HF rats. Along with its comparable anti-inflammatory effect, add-on AZE further improved all of these parameter changes by OLM. Furthermore, combination therapy significantly enhanced the improvement of LV fibrosis, hypertrophy, stiffness, and dysfunction by OLM. In vitro, H 2 O 2 stimulated Cat S mRNA and protein expression and activity, and these increases were abolished by pretreatment with the antioxidants such as MnTmPyp (50 μmol/L) and N-acetylcysteine (5 mmol/L) as well as a NADPH oxidase inhibitor apocynin (100 μmol/L) in culture CMCs, SMCs, and macrophages (n = 6, P< 0.01). Conclusions: OLM and a combination of OLM and AZE exerted cardioprotective effects in hypertensive HF, via elastolytic Cat activation inhibition by the reduction of NADPH oxidase-dependent superoxide anion production. AZE enhanced the cardioprotective effects of OLM. Thus, the combination of ARB with CBB is a promising potential therapeutic strategy for H-HF.

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Tetrahydrobiopterin Slows the Progression of Atherosclerosis

Pteridines ◽

10.1515/pteridines.2007.18.1.115 ◽

2007 ◽

Vol 18 (1) ◽

pp. 115-121

Author(s):

Suzuki Kunihiro ◽

Yoshiyuki Hattori ◽

Teruo Jojima ◽

Atsuko Tomizawa ◽

Toshie Okayasu ◽

...

Keyword(s):

Drinking Water ◽

Endothelial Dysfunction ◽

Nadph Oxidase ◽

Endothelial Function ◽

Oral Administration ◽

Mrna Expression ◽

Inflammatory Factors ◽

Apoe Ko Mice ◽

Progression Of Atherosclerosis ◽

Apoe Ko

Abstract We investigated whether oral tetrahydrobiopterin (BH4) treatment might slow the progression of atherosclerosis using hypercholesterolemic ApoE-knockout (KO) mice. We report that ingesting BH4 in drinking water is effective to inhibit atherogenesis in mice. Furthermore, we report that BH4 treatment improves endothelial dysfunction and attenuates increased mRNA expression of NADPH oxidase components, as well as a number of inflammatory factors, such as LOX-1 and MCP-1, in the aortas of ApoE-KO mice. Strategies such as oral administration of BH4 to ensure continuous BH4 availability may be effective in restoring NO-mediated endothelial function and limiting vascular disease and the progression of atherosclerosis.

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Coronary endothelial dysfunction after cardiomyocyte-specific mineralocorticoid receptor overexpression

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.00552.2010 ◽

2011 ◽

Vol 300 (6) ◽

pp. H2035-H2043 ◽

Cited By ~ 35

Author(s):

Julie Favre ◽

Ji Gao ◽

An Di Zhang ◽

Isabelle Remy-Jouet ◽

Antoine Ouvrard-Pascaud ◽

...

Keyword(s):

Reactive Oxygen Species ◽

Endothelial Dysfunction ◽

Nadph Oxidase ◽

Coronary Arteries ◽

Mineralocorticoid Receptor ◽

Vascular Dysfunction ◽

Reactive Oxygen ◽

Oxidase Inhibitor ◽

Oxygen Species ◽

Coronary Endothelial Dysfunction

The deleterious effects of aldosterone excess demonstrated in cardiovascular diseases might be linked in part to coronary vascular dysfunction. However, whether such vascular dysfunction is a cause or a consequence of the changes occurring in the cardiomyocytes is unclear. Moreover, the possible link between mineralocorticoid receptor (MR)-mediated effects on the cardiomyocyte and the coronary arteries is unknown. Thus we used a mouse model with conditional, cardiomyocyte-specific overexpression of human MR (hMR) and observed the effects on endothelial function in isolated coronary segments. hMR overexpression decreased the nitric oxide (NO)-mediated relaxing responses to acetylcholine in coronary arteries (but not in peripheral arteries), and this was prevented by a 1-mo treatment either with an MR antagonist, vitamin E/vitamin C, or a NADPH oxidase inhibitor. hMR overexpression did not affect coronary endothelial NO synthase content nor its level of phosphorylation on serine 1177, but increased cardiac levels of reactive oxygen species, cardiac NADPH oxidase (NOX) activity, and expression of the NOX subunit gp91phox, which was limited to endothelial cells. Thus an increase in hMR activation, restricted to cardiomyocytes, is sufficient to induce a severe coronary endothelial dysfunction. We suggest a new paracrine mechanism by which cardiomyocytes trigger a NOX-dependent, reactive oxygen species-mediated coronary endothelial dysfunction.

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Abstract P342: Mitochondria-Targeted Antioxidant Therapy Prevents Angiotensin II--Mediated Connexin43 Remodeling and Sudden Arrhythmic Death

Circulation Research ◽

10.1161/res.109.suppl_1.ap342 ◽

2011 ◽

Vol 109 (suppl_1) ◽

Author(s):

Ali A Sovari ◽

Shadi Zandieh ◽

Shahriar Iravanian ◽

Lianzhi Gu ◽

Euy-Myong Jeong ◽

...

Keyword(s):

Angiotensin Ii ◽

Nadph Oxidase ◽

Protein Carbonyl ◽

Oxidase Inhibitor ◽

Control Treatment ◽

Arrhythmic Death ◽

Protein Levels ◽

Mitochondrial Superoxide ◽

Remodeling Suppression ◽

The Right

Introduction: Angiotensin II activation and associated elevation in ROS have been implicated in pathogenesis of arrhythmia. Nevertheless commonly used antioxidants have been ineffective in clinical trials. We created a transgenic mouse model of cardiac restricted overexpression of ACE (ACE8/8). These mice show spontaneous VT/ VF, SCD, and a reduction in Cx43 level, which impairs conduction and predisposes to arrhythmia. We sought to determine the role and the major source of ROS by angiotensin II in VT/ VF and Cx43 remodeling. Method: Wild type and ACE8/8 mice with and without 2 weeks of treatment with a NOS inhibitor (L-NIO, 25mg/Kg IP injections daily), a mitochondria-targeted antioxidant (Mito-TEMPO, 0.7mg/Kg IP injections daily), a NADPH oxidase inhibitor (Apocynin 80mg/L in drinking water), and ACE8/8 crossed with P67DN were studied. Western blotting (with derivatization to dinitrophenylhydrozone to detect oxidized protein levels), detection of superoxide production in mitochondria by red mitochondrial superoxide indicator and immunohistochemistry staining for Cx43 were performed. EP study was performed by a 1.1F octapolar catheter through pacing the right ventricle using a burst pacing protocol. Results: Proteins were more oxidized (increased protein-carbonyl detection), and Cx43 was reduced in ACE8/8 to 33% of control. Treatment with Mito-TEMPO prevented SCD and improved survival in ACE8/8 mice (p=0.0005, hazard ratio 4.76 with 95% CI of 1.96 to 11.53). Inducibility of VT/VF was higher in ACE8/8 mice compare to WT (87.5% vs. 2.3%) and VT inducibility was reduced with Mito-TEMPO treatment (50% in treatment group). Cx43 level was increased by 1.7 fold with Mito-TEMPO treatment. Treatments with L-NIO, Apocynin and crossing with P67DN mice did not prevent VT/VF and SCD in ACE8/8 mice. Conclusion: In a model of angiotensin II activation mitochondria-targeted antioxidant, prevents VT/VF/SCD and Cx43 remodeling. Suppression of NADPH oxidase activity by Apocynin and crossing the ACE8/8 mice with P67DN or inhibition of NOS by L-NIO did not prevent the arrhythmic deaths in ACE8/8 mice. This result suggests that mitochondria are the major source of ROS by angiotensin II and mitochondria-targeted antioxidants may be effective antiarrhythmic drugs.

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Red wine polyphenols prevent endothelial dysfunction induced by endothelin-1 in rat aorta: role of NADPH oxidase

Clinical Science ◽

10.1042/cs20100311 ◽

2010 ◽

Vol 120 (8) ◽

pp. 321-333 ◽

Cited By ~ 27

Author(s):

Rocío López-Sepúlveda ◽

Manuel Gómez-Guzmán ◽

Maria José Zarzuelo ◽

Miguel Romero ◽

Manuel Sánchez ◽

...

Keyword(s):

Endothelial Dysfunction ◽

Nadph Oxidase ◽

Endothelial Function ◽

Oxidase Activity ◽

Red Wine ◽

Vascular Wall ◽

Nadph Oxidase Activity ◽

Wine Polyphenols ◽

Red Wine Polyphenols ◽

O2 Production

RWPs (red wine polyphenols) exert antihypertensive effects and improve endothelial function by reducing the plasma levels of ET-1 (endothelin-1) and the subsequent vascular production of O2•− (superoxide anion). Our present study was designed to evaluate whether RWPs act directly in the vascular wall improving endothelial dysfunction and O2•− production induced by ET-1 and to analyse the compounds responsible for these protective effects. We incubated rat isolated aortic rings in the presence or absence of ET-1 (10 nM) and RWPs (10−4 to 10−2 g/l) or catechin (0.2 μM), epicatechin (10 μM) and resveratrol (0.1 μM). ET-1 reduced the relaxant responses to acetylcholine, increased intracellular O2•− production, NADPH oxidase activity and protein expression of NADPH oxidase subunit p47phox. All these changes were prevented by RWPs. The preventive effects of RWPs were unaffected by co-incubation with either ICI-182780, an ER (oestrogen receptor) antagonist, or GW9662, a PPARγ (peroxisome-proliferator-activated receptor γ) antagonist. RWPs inhibited the phosphorylation of the mitogen-activated protein kinase, ERK1/2 (extracellular signal-regulated kinase 1/2), a key regulator of p47phox expression in response to ET-1. When the isolated polyphenols were tested, at the concentrations found in 10−2 g/l RWPs, only epicatechin prevented endothelial dysfunction and all biochemical changes induced by ET-1 in the vascular wall. Taken together, these results indicate that RWPs prevent ET-1-induced vascular O2•− production by reducing overexpression of p47phox and the subsequent increased NADPH oxidase activity, leading to improvement in endothelial function. The effects of RWPs appear to be independent of ER and PPARγ activation and are related to ERK1/2 inhibition.

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Homocysteine stimulates NADPH oxidase-mediated superoxide production leading to endothelial dysfunction in rats

Canadian Journal of Physiology and Pharmacology ◽

10.1139/y07-112 ◽

2007 ◽

Vol 85 (12) ◽

pp. 1236-1247 ◽

Cited By ~ 59

Author(s):

Vathsala E.R. Edirimanne ◽

Connie W.H. Woo ◽

Yaw L. Siow ◽

Grant N. Pierce ◽

Jiu Y. Xie ◽

...

Keyword(s):

Endothelial Dysfunction ◽

Nadph Oxidase ◽

Superoxide Anion ◽

Vascular Wall ◽

Oxidase Inhibitor ◽

Vascular Cells ◽

Superoxide Anion Production ◽

Anion Production ◽

Nadph Oxidase Activation ◽

Endothelium Dependent Relaxation

Elevation of blood homocysteine (Hcy) levels (hyperhomocysteinemia) is a risk factor for cardiovascular disorders. We previously reported that oxidative stress contributed to Hcy-induced inflammatory response in vascular cells. In this study, we investigated whether NADPH oxidase was involved in Hcy-induced superoxide anion accumulation in the aorta, which leads to endothelial dysfunction during hyperhomocysteinemia. Hyperhomocysteinemia was induced in rats fed a high-methionine diet. NADPH oxidase activity and the levels of superoxide and peroxynitrite were markedly increased in aortas isolated from hyperhomocysteinemic rats. Expression of the NADPH oxidase subunit p22phox increased significantly in these aortas. Administration of an NADPH oxidase inhibitor (apocynin) not only attenuated aortic superoxide and peroxynitrite to control levels but also restored endothelium-dependent relaxation in the aortas of hyperhomocysteinemic rats. Transfection of human endothelial cells or vascular smooth muscle cells with p22phox siRNA to inhibit NADPH oxidase activation effectively abolished Hcy-induced superoxide anion production, thus indicating the direct involvement of NADPH oxidase in elevated superoxide generation in vascular cells. Taken together, these results suggest that Hcy-stimulated superoxide anion production in the vascular wall is mediated through the activation of NADPH oxidase, which leads to endothelial dysfunction during hyperhomocysteinemia.

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