Mitochondrial oxidative stress corrupts coronary collateral growth by activating adenosine monophosphate activated kinase-alpha signaling.
AMP-Activated Protein Kinases/*metabolism; Animal; Animals; Body Weight/physiology; Cells; collateral circulation; coronary circulation; Coronary Vessels/cytology/*enzymology; Cultured; Disease Models; Endothelial Cells/cytology/*enzymology; Humans; Inbred WKY; Ischemia/metabolism/pathology; mitochondria; Mitochondria/drug effects/*metabolism; Myocardium/enzymology/pathology; Oxidative Stress/*physiology; Rats; reactive oxygen species; Rotenone/pharmacology; Signal Transduction/*physiology; TOR Serine-Threonine Kinases/metabolism; Uncoupling Agents/pharmacology
OBJECTIVE: Our goal was to determine the mechanism by which mitochondrial oxidative stress impairs collateral growth in the heart. APPROACH AND RESULTS: Rats were treated with rotenone (mitochondrial complex I inhibitor that increases reactive oxygen species production) or sham-treated with vehicle and subjected to repetitive ischemia protocol for 10 days to induce coronary collateral growth. In control rats, repetitive ischemia increased flow to the collateral-dependent zone; however, rotenone treatment prevented this increase suggesting that mitochondrial oxidative stress compromises coronary collateral growth. In addition, rotenone also attenuated mitochondrial complex I activity and led to excessive mitochondrial aggregation. To further understand the mechanistic pathway(s) involved, human coronary artery endothelial cells were treated with 50 ng/mL vascular endothelial growth factor, 1 micromol/L rotenone, and rotenone/vascular endothelial growth factor for 48 hours. Vascular endothelial growth factor induced robust tube formation; however, rotenone completely inhibited this effect (P\textless0.05 rotenone versus vascular endothelial growth factor treatment). Inhibition of tube formation by rotenone was also associated with significant increase in mitochondrial superoxide generation. Immunoblot analyses of human coronary artery endothelial cells with rotenone treatment showed significant activation of adenosine monophosphate activated kinase (AMPK)-alpha and inhibition of mammalian target of rapamycin and p70 ribosomal S6 kinase. Activation of AMPK-alpha suggested impairments in energy production, which was reflected by decrease in O2 consumption and bioenergetic reserve capacity of cultured cells. Knockdown of AMPK-alpha (siRNA) also preserved tube formation during rotenone, suggesting the negative effects were mediated by the activation of AMPK-alpha. Conversely, expression of a constitutively active AMPK-alpha blocked tube formation. CONCLUSIONS: We conclude that activation of AMPK-alpha during mitochondrial oxidative stress inhibits mammalian target of rapamycin signaling, which impairs phenotypic switching necessary for the growth of blood vessels.
Pung Yuh Fen; Sam Wai Johnn; Stevanov Kelly; Enrick Molly; Chen Chwen-Lih; Kolz Christopher; Thakker Prashanth; Hardwick James P; Chen Yeong-Renn; Dyck Jason R B; Yin Liya; Chilian William M
Arteriosclerosis, thrombosis, and vascular biology
2013
2013-08
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1161/ATVBAHA.113.301591" target="_blank" rel="noreferrer noopener">10.1161/ATVBAHA.113.301591</a>
Acute exercise and gender alter cardiac autonomic tonus differently in hypertensive and normotensive rats.
*Sex Characteristics; Adrenergic alpha-Antagonists/pharmacology; Animals; Autonomic Nervous System/drug effects/*physiopathology; Blood Pressure; Female; Heart Rate/physiology; Heart/*innervation; Hypertension/*physiopathology; Inbred SHR; Inbred WKY; Male; Metoprolol/pharmacology; N-Methylscopolamine/pharmacology; Parasympathetic Nervous System/drug effects/physiopathology; Parasympatholytics/pharmacology; Physical Exertion/*physiology; Rats; Sympathetic Nervous System/drug effects/physiopathology
Arterial pressure (AP), heart rate (HR), cardiac sympathetic tonus (ST), and parasympathetic tonus (PT) were determined in spontaneously hypertensive rats (SHR, 8 male and 8 female) and Wistar-Kyoto normotensive rats (WKY, 8 male and 12 female) before and after acute exercise. Before exercise, hypertensive rats (regardless of gender) had an increased ST (+15 beats/min), increased resting HR (+12 beats/min), and decreased PT (-11 beats/min). Similarly, female rats (regardless of strain) also had an increased ST (+15 beats/min), increased resting HR (+39 beats/min), and decreased PT (-14 beats/min). Hypertensive rats had a significant reduction in AP (-17 +/- 3 mmHg), ST (-26 beats/min), PT (-7 beats/min), and HR (-14 beats/min) after exercise. In contrast, AP was not reduced in normotensive rats and ST (+18 beats/min) and HR (+42 beats/min) were increased in female normotensive rats after exercise. However, male normotensive rats had a postexercise reduction in ST (-14 beats/min) and HR (-19 beats/min). In summary, AP, ST, and resting HR were higher whereas PT was lower in hypertensive vs. normotensive rats. Furthermore, females had a higher resting HR, intrinsic HR, and ST and lower PT than male rats. These data demonstrate that gender and the resting level of AP influence cardiac autonomic regulation.
Chandler M P; DiCarlo S E
The American journal of physiology
1998
1998-02
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1152/ajpregu.1998.274.2.r510" target="_blank" rel="noreferrer noopener">10.1152/ajpregu.1998.274.2.r510</a>
Optimal reactive oxygen species concentration and p38 MAP kinase are required for coronary collateral growth.
*Collateral Circulation/drug effects; *Coronary Circulation/drug effects; *MAP Kinase Signaling System/drug effects; Acetophenones/pharmacology; Animal; Animals; Blood Flow Velocity; Cells; Coronary Vessels/surgery; Cultured; Disease Models; Ditiocarb/pharmacology; Endothelial Cells/drug effects/enzymology/*metabolism; Enzyme Inhibitors/pharmacology; Humans; Imidazoles/pharmacology; Inbred WKY; Ligation; Male; Myocardial Reperfusion Injury/enzymology/metabolism/*physiopathology; NADPH Oxidases/antagonists & inhibitors/metabolism; Neovascularization; Onium Compounds/pharmacology; Oxygenases/antagonists & inhibitors/metabolism; p38 Mitogen-Activated Protein Kinases/antagonists & inhibitors/*metabolism; Physiologic; Pyridines/pharmacology; Rats; Reactive Oxygen Species/*metabolism; Superoxide Dismutase/antagonists & inhibitors/metabolism; Vascular Endothelial Growth Factor A/metabolism
Reactive oxygen species (ROS) are implicated in coronary collateral growth (CCG). We evaluated the requirement for ROS in human coronary artery endothelial cell (HCAEC) tube formation, CCG in vivo, and signaling (p38 MAP kinase) by which ROS may stimulate vascular growth. The flavin-containing oxidase inhibitor diphenyleneiodonium (DPI) or the superoxide dismutase inhibitor diethyldithiocarbamate (DETC) blocked vascular endothelial growth factor-induced HCAEC tube formation in Matrigel. We assessed the effect of DPI and DETC on CCG in a rat model of repetitive ischemia (RI) (40 s left anterior descending coronary artery occlusion every 20 min for 2 h 20 min, 3 times/day, 10 days). DPI or DETC was given intraperitoneally, or the NAD(P)H oxidase inhibitor apocynin was given in drinking water. Collateral-dependent flow (measured by using microspheres) was expressed as a ratio of normal and ischemic zone flows. In sham-operated rats, collateral flow in the ischemic zone was 18 +/- 6% of normal zone; in the RI group, collateral flow in the ischemic zone was 83 +/- 5% of normal zone. DPI prevented the increase in collateral flow after RI (25 +/- 4% of normal zone). Similar results were obtained with apocynin following RI (32 +/- 7% of that in the normal zone). DETC achieved similar results (collateral flow after RI was 21 +/- 2% of normal zone). DPI and DETC blocked RI-induced p38 MAP kinase activation in response to vascular endothelial growth factor and RI. These results demonstrate a requirement for optimal ROS concentration in HCAEC tube formation, CCG, and p38 MAP kinase activation. p38 MAP kinase inhibition prevented HCAEC tube formation and partially blocked RI-induced CCG (42 +/- 7% of normal zone flow), indicating that p38 MAP kinase is a critical signaling mediator of CCG.
Rocic Petra; Kolz Christopher; Reed Ryan; Potter Barry; Chilian William M
American journal of physiology. Heart and circulatory physiology
2007
2007-06
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1152/ajpheart.01330.2006" target="_blank" rel="noreferrer noopener">10.1152/ajpheart.01330.2006</a>