Nitrogen Dioxide Inhalation Exposures Induce Cardiac Mitochondrial Reactive Oxygen Species Production, Impair Mitochondrial Function and Promote Coronary Endothelial Dysfunction

Traffic air pollution is a major health problem and is recognized as an important risk factor for cardiovascular (CV) diseases. In a previous experimental study, we showed that diesel exhaust (DE) exposures induced cardiac mitochondrial and CV dysfunctions associated with the gaseous phase. Here, we hypothesized that NO2 exposures to levels close to those found in DE induce a mitochondrial reactive oxygen species (ROS) production, which contribute to an endothelial dysfunction, an early indicator for numerous CV diseases. For this, we studied the effects of NO2 on ROS production and its impacts on the mitochondrial, coronary endothelial and cardiac functions, after acute (one single exposure) and repeated (three h/day, five days/week for three weeks) exposures in Wistar rats. Acute NO2 exposure induced an early but reversible mitochondrial ROS production. This event was isolated since neither mitochondrial function nor endothelial function were impaired, whereas cardiac function assessment showed a reversible left ventricular dysfunction. Conversely, after three weeks of exposure this alteration was accompanied by a cardiac mitochondrial dysfunction highlighted by an alteration of adenosine triphosphate (ATP) synthesis and oxidative phosphorylation and an increase in mitochondrial ROS production. Moreover, repeated NO2 exposures promoted endothelial dysfunction of the coronary arteries, as shown by reduced acetylcholine-induced vasodilatation, which was due, at least partially, to a superoxide-dependent decrease of nitric oxide (NO) bioavailability. This study shows that NO2 exposures impair cardiac mitochondrial function, which, in conjunction with coronary endothelial dysfunction, contributes to cardiac dysfunction. Together, these results clearly identify NO2 as a probable risk factor in ischemic heart diseases.

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Survival Signaling by C-RAF: Mitochondrial Reactive Oxygen Species and Ca2+ Are Critical Targets

Molecular and Cellular Biology ◽

10.1128/mcb.00683-07 ◽

2008 ◽

Vol 28 (7) ◽

pp. 2304-2313 ◽

Cited By ~ 31

Author(s):

Andrey V. Kuznetsov ◽

Julija Smigelskaite ◽

Christine Doblander ◽

Manickam Janakiraman ◽

Martin Hermann ◽

...

Keyword(s):

Oxidative Stress ◽

Reactive Oxygen Species ◽

Cell Death ◽

Reactive Oxygen ◽

Ros Production ◽

Oxygen Species ◽

Mitochondrial Reactive Oxygen Species ◽

Mitochondrial Ros ◽

Survival Signaling ◽

First Time

ABSTRACT Survival signaling by RAF occurs through largely unknown mechanisms. Here we provide evidence for the first time that RAF controls cell survival by maintaining permissive levels of mitochondrial reactive oxygen species (ROS) and Ca2+. Interleukin-3 (IL-3) withdrawal from 32D cells resulted in ROS production, which was suppressed by activated C-RAF. Oncogenic C-RAF decreased the percentage of apoptotic cells following treatment with staurosporine or the oxidative stress-inducing agent tert-butyl hydroperoxide. However, it was also the case that in parental 32D cells growing in the presence of IL-3, inhibition of RAF signaling resulted in elevated mitochondrial ROS and Ca2+ levels. Cell death is preceded by a ROS-dependent increase in mitochondrial Ca2+, which was absent from cells expressing transforming C-RAF. Prevention of mitochondrial Ca2+ overload after IL-3 deprivation increased cell viability. MEK was essential for the mitochondrial effects of RAF. In summary, our data show that survival control by C-RAF involves controlling ROS production, which otherwise perturbs mitochondrial Ca2+ homeostasis.

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Coronary endothelial dysfunction and mitochondrial reactive oxygen species in type 2 diabetic mice

AJP Cell Physiology ◽

10.1152/ajpcell.00234.2013 ◽

2013 ◽

Vol 305 (10) ◽

pp. C1033-C1040 ◽

Cited By ~ 34

Author(s):

Young-Eun Cho ◽

Aninda Basu ◽

Anzhi Dai ◽

Michael Heldak ◽

Ayako Makino

Keyword(s):

Reactive Oxygen Species ◽

Blood Flow ◽

Endothelial Dysfunction ◽

Reactive Oxygen ◽

Oxygen Species ◽

Vascular Relaxation ◽

Mitochondrial Ros ◽

Coronary Endothelial Dysfunction ◽

Type 2 Diabetic

Endothelial cell (EC) dysfunction is implicated in cardiovascular diseases, including diabetes. The decrease in nitric oxide (NO) bioavailability is the hallmark of endothelial dysfunction, and it leads to attenuated vascular relaxation and atherosclerosis followed by a decrease in blood flow. In the heart, decreased coronary blood flow is responsible for insufficient oxygen supply to cardiomyocytes and, subsequently, increases the incidence of cardiac ischemia. In this study we investigate whether and how reactive oxygen species (ROS) in mitochondria contribute to coronary endothelial dysfunction in type 2 diabetic (T2D) mice. T2D was induced in mice by a high-fat diet combined with a single injection of low-dose streptozotocin. ACh-induced vascular relaxation was significantly attenuated in coronary arteries (CAs) from T2D mice compared with controls. The pharmacological approach reveals that NO-dependent, but not hyperpolarization- or prostacyclin-dependent, relaxation was decreased in CAs from T2D mice. Attenuated ACh-induced relaxation in CAs from T2D mice was restored toward control level by treatment with mitoTempol (a mitochondria-specific O2− scavenger). Coronary ECs isolated from T2D mice exhibited a significant increase in mitochondrial ROS concentration and decrease in SOD2 protein expression compared with coronary ECs isolated from control mice. Furthermore, protein ubiquitination of SOD2 was significantly increased in coronary ECs isolated from T2D mice. These results suggest that augmented SOD2 ubiquitination leads to the increase in mitochondrial ROS concentration in coronary ECs from T2D mice and attenuates coronary vascular relaxation in T2D mice.

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Clinical aspects of reactive oxygen and nitrogen species

Biochemical Society Symposium ◽

10.1042/bss0710121 ◽

2004 ◽

Vol 71 ◽

pp. 121-133 ◽

Cited By ~ 25

Author(s):

Ascan Warnholtz ◽

Maria Wendt ◽

Michael August ◽

Thomas Münzel

Keyword(s):

Oxidative Stress ◽

Reactive Oxygen Species ◽

Risk Factor ◽

Endothelial Dysfunction ◽

Vascular Tissue ◽

Rapid Development ◽

Reactive Oxygen ◽

Clinical Aspects ◽

No Production ◽

Oxygen Species

Endothelial dysfunction in the setting of cardiovascular risk factors, such as hypercholesterolaemia, hypertension, diabetes mellitus and chronic smoking, as well as in the setting of heart failure, has been shown to be at least partly dependent on the production of reactive oxygen species in endothelial and/or smooth muscle cells and the adventitia, and the subsequent decrease in vascular bioavailability of NO. Superoxide-producing enzymes involved in increased oxidative stress within vascular tissue include NAD(P)H-oxidase, xanthine oxidase and endothelial nitric oxide synthase in an uncoupled state. Recent studies indicate that endothelial dysfunction of peripheral and coronary resistance and conductance vessels represents a strong and independent risk factor for future cardiovascular events. Ways to reduce endothelial dysfunction include risk-factor modification and treatment with substances that have been shown to reduce oxidative stress and, simultaneously, to stimulate endothelial NO production, such as inhibitors of angiotensin-converting enzyme or the statins. In contrast, in conditions where increased production of reactive oxygen species, such as superoxide, in vascular tissue is established, treatment with NO, e.g. via administration of nitroglycerin, results in a rapid development of endothelial dysfunction, which may worsen the prognosis in patients with established coronary artery disease.

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Protein Kinase D Mediates Mitochondrion-to-Nucleus Signaling and Detoxification from Mitochondrial Reactive Oxygen Species

Molecular and Cellular Biology ◽

10.1128/mcb.25.19.8520-8530.2005 ◽

2005 ◽

Vol 25 (19) ◽

pp. 8520-8530 ◽

Cited By ~ 167

Author(s):

Peter Storz ◽

Heike Döppler ◽

Alex Toker

Keyword(s):

Reactive Oxygen Species ◽

Transcription Factor ◽

Protein Kinase ◽

Reactive Oxygen ◽

Protein Kinase D ◽

Oxygen Species ◽

Mitochondrial Reactive Oxygen Species ◽

Mitochondrial Oxidative Stress ◽

Cellular Survival ◽

Mitochondrial Ros

ABSTRACT Efficient elimination of mitochondrial reactive oxygen species (mROS) correlates with increased cellular survival and organism life span. Detoxification of mitochondrial ROS is regulated by induction of the nuclear SOD2 gene, which encodes the manganese-dependent superoxide dismutase (MnSOD). However, the mechanisms by which mitochondrial oxidative stress activates cellular signaling pathways leading to induction of nuclear genes are not known. Here we demonstrate that release of mROS activates a signal relay pathway in which the serine/threonine protein kinase D (PKD) activates the NF-κB transcription factor, leading to induction of SOD2. Conversely, the FOXO3a transcription factor is dispensable for mROS-induced SOD2 induction. PKD-mediated MnSOD expression promotes increased survival of cells upon release of mROS, suggesting that mitochondrion-to-nucleus signaling is necessary for efficient detoxification mechanisms and cellular viability.

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Ultraendurance exercise increases the production of reactive oxygen species in isolated mitochondria from human skeletal muscle

Journal of Applied Physiology ◽

10.1152/japplphysiol.00966.2009 ◽

2010 ◽

Vol 108 (4) ◽

pp. 780-787 ◽

Cited By ~ 47

Author(s):

Kent Sahlin ◽

Irina G. Shabalina ◽

C. Mikael Mattsson ◽

Linda Bakkman ◽

Maria Fernström ◽

...

Keyword(s):

Reactive Oxygen Species ◽

Oxidative Damage ◽

Vastus Lateralis ◽

Reactive Oxygen ◽

Ros Production ◽

Oxygen Species ◽

Work Intensity ◽

Isolated Mitochondria ◽

Mitochondrial Ros

Exercise-induced oxidative stress is important for the muscular adaptation to training but may also cause muscle damage. We hypothesized that prolonged exercise would increase mitochondrial production of reactive oxygen species (ROS) measured in vitro and that this correlates with oxidative damage. Eight male athletes (24–32 yr) performed ultraendurance exercise (kayaking/running/cycling) with an average work intensity of 55% V̇o2peak for 24 h. Muscle biopsies were taken from vastus lateralis before exercise, immediately after exercise, and after 28 h of recovery. The production of H2O2 was measured fluorometrically in isolated mitochondria with the Amplex red and peroxidase system. Succinate-supported mitochondrial H2O2 production was significantly increased after exercise (73% higher, P = 0.025) but restored to the initial level at recovery. Plasma level of free fatty acids (FFA) increased fourfold and exceeded 1.2 mmol/l during the last 6 h of exercise. Plasma FFA at the end of exercise was significantly correlated to mitochondrial ROS production ( r = 0.74, P < 0.05). Mitochondrial content of 4-hydroxy-nonenal-adducts (a marker of oxidative damage) was increased only after recovery and was not correlated with mitochondrial ROS production. Total thiol group level and glutathione peroxidase activity were elevated after recovery. In conclusion, ultraendurance exercise increases ROS production in isolated mitochondria, but this is reversed after 28 h recovery. Mitochondrial ROS production was not correlated with oxidative damage of mitochondrial proteins, which was increased at recovery but not immediately after exercise.

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OxLDL enhances L-type Ca2+ currents via lysophosphatidylcholine-induced mitochondrial reactive oxygen species (ROS) production

Cardiovascular Research ◽

10.1016/j.cardiores.2005.11.019 ◽

2006 ◽

Vol 69 (4) ◽

pp. 855-864 ◽

Cited By ~ 32

Author(s):

I FEARON

Keyword(s):

Reactive Oxygen Species ◽

Reactive Oxygen ◽

Ros Production ◽

Oxygen Species ◽

Mitochondrial Reactive Oxygen Species

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Mitochondrial reactive oxygen species contribute to high NaCl-induced activation of the transcription factor TonEBP/OREBP

AJP Renal Physiology ◽

10.1152/ajprenal.00378.2005 ◽

2006 ◽

Vol 290 (5) ◽

pp. F1169-F1176 ◽

Cited By ~ 40

Author(s):

Xiaoming Zhou ◽

Joan D. Ferraris ◽

Maurice B. Burg

Keyword(s):

Reactive Oxygen Species ◽

Transcription Factor ◽

Nuclear Translocation ◽

Reactive Oxygen ◽

Hek293 Cells ◽

Organic Osmolytes ◽

Ros Production ◽

Oxygen Species ◽

Hypertonic Stress ◽

Mitochondrial Ros

Hypertonicity activates the transcription factor tonicity-responsive enhancer/osmotic response element binding protein (TonEBP/OREBP), resulting in increased expression of genes involved in osmoprotective accumulation of organic osmolytes, including glycine betaine, and in increased expression of osmoprotective heat shock proteins. Our previous studies showed that high NaCl increases reactive oxygen species (ROS), which contribute to activation of TonEBP/OREBP. Mitochondria are a major source of ROS. The purpose of the present study was to examine whether mitochondria produce the ROS that contribute to activation of TonEBP/OREBP. We inhibited mitochondrial ROS production in HEK293 cells with rotenone and myxothiazol, which inhibit mitochondrial complexes I and III, respectively. Rotenone (250 nM) and myxothiazol (12 nM) reduce high NaCl-induced ROS over 40%, whereas apocynin (100 μM), an inhibitor of NADPH oxidase, and allopurinol (100 μM), an inhibitor of xanthine oxidase, have no significant effect. Rotenone and myxothiazol reduce high NaCl-induced increases in TonEBP/OREBP transcriptional activity (ORE/TonE reporter assay) and BGT1 (betaine transporter) mRNA abundance ranging from 53 to 69%. They inhibit high NaCl-induced TonEBP/OREBP transactivating activity, but not its nuclear translocation. Release of ATP into the medium on hypertonic stress has been proposed to be a signal that triggers cellular osmotic responses. However, we do not detect release of ATP into the medium or inhibition of high NaCl-induced ORE/TonE reporter activity by an ATPase, apyrase (20 U/ml), indicating that high NaCl-induced activation of TonEBP/OREBP is not mediated by release of ATP. We conclude that high NaCl increases mitochondrial ROS production, which contributes to the activation of TonEBP/OREBP by increasing its transactivating activity.

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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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Reactive oxygen species cause endothelial dysfunction in chronic flow overload

Journal of Applied Physiology ◽

10.1152/japplphysiol.00786.2009 ◽

2011 ◽

Vol 110 (2) ◽

pp. 520-527 ◽

Cited By ~ 17

Author(s):

X. Lu ◽

X. Guo ◽

C. D. Wassall ◽

M. D. Kemple ◽

J. L. Unthank ◽

...

Keyword(s):

Reactive Oxygen Species ◽

Shear Stress ◽

Endothelial Dysfunction ◽

Nadph Oxidase ◽

Group Treatment ◽

Carotid Arteries ◽

Reactive Oxygen ◽

Ros Production ◽

Oxygen Species ◽

Enos Uncoupling

Although elevation of shear stress increases production of vascular reactive oxygen species (ROS), the role of ROS in chronic flow overload (CFO) has not been well investigated. We hypothesize that CFO increases ROS production mediated in part by NADPH oxidase, which leads to endothelial dysfunction. In six swine, CFO in carotid arteries was induced by contralateral ligation for 1 wk. In an additional group, six swine received apocynin (NADPH oxidase blocker and anti-oxidant) treatment in conjunction with CFO for 1 wk. The blood flow in carotid arteries increased from 189.2 ± 25.3 ml/min (control) to 369.6 ± 61.9 ml/min (CFO), and the arterial diameter increased by 8.6%. The expressions of endothelial nitric oxide synthase (eNOS), p22/p47phox, and NOX2/NOX4 were upregulated. ROS production increased threefold in response to CFO. The endothelium-dependent vasorelaxation was compromised in the CFO group. Treatment with apocynin significantly reduced ROS production in the vessel wall, preserved endothelial function, and inhibited expressions of p22/p47phox and NOX2/NOX4. Although the process of CFO remodeling to restore the wall shear stress has been thought of as a physiological response, the present data implicate NADPH oxidase-produced ROS and eNOS uncoupling in endothelial dysfunction at 1 wk of CFO.

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