on July 13, 2006
Published online before print July 13, 2006, doi: 10.1161/01.ATV.0000236204.37119.8d
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Submitted on May 4, 2006
Accepted on June 21, 2006
Protection of Human Vascular Smooth Muscle Cells From H2O2-Induced Apoptosis Through Functional Codependence Between HO-1 and AKT
Keith R. Brunt ;
From the Departments of Physiology (K.R.B., K.K.F., G.K., C.A.W., L.G.M.) and Anatomy and Cell Biology (M.Y.T., S.C.P.), Queen’s University, Kingston Ontario, Canada.
* To whom correspondence should be addressed. E-mail: melol{at}post.queensu.ca.
Objective--Oxidative stress (OS) induces smooth muscle cell apoptosis in the atherosclerotic plaque, leading to plaque instability and rupture. Heme oxygenase-1 (HO-1) exerts cytoprotective effects in the vessel wall. Recent evidence suggests that PKB/Akt may modulate HO-1 activity. This study examined the role of Akt in mediating the cytoprotective effects of HO-1 in OS-induced apoptosis of human aortic smooth muscle cells (HASMCs).
Methods and Results--HASMCs were transduced with retroviral vectors expressing HO-1, Akt ,or GFP and exposed to H2O2. Cell viability was assessed by MTT assay. OS was determined by CM-H2DCFDA fluorescence, and apoptosis was assessed by terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL), caspase-3 activity, and Bcl-2/Bad levels. Mitochondrial membrane potential (
m) was assessed by fluorescence-activated cell sorter (FACS) using JC-1. HO-1 reduced H2O2-induced OS and apoptosis. Akt knockdown removed the protective effect of HO-1 on m during exposure to H2O2. Conversely, HO-1 knockdown removed the protective effect of Akt on m. Inhibition of PI3K-Akt reduced induction of HO-1 protein expression by H2O2 and blocked its anti-apoptotic effects. The Akt-mediated upregulation of HO-1 was dependent on activation of HO-1 promoter by Nrf2.
Conclusion--HO-1 and Akt exert codependent cytoprotective effects against OS-induced apoptosis in HASMCs. These findings may have implications for the design of novel therapeutic strategies for plaque stabilization.
Key words: apoptosis • flow cytometry • mitochondrial membrane potential • oxidative stress • vascular smooth muscle cells
This article has been cited by other articles:
 |
|
 |
|
  Y.-L. Huang, C.-M. Wu, G.-Y. Shi, G. C.-C. Wu, H. Lee, M.-J. Jiang, H.-L. Wu, and H.-Y. Yang Nestin Serves as a Prosurvival Determinant that is Linked to the Cytoprotective Effect of Epidermal Growth Factor in Rat Vascular Smooth Muscle Cells J. Biochem., September 1, 2009; 146(3): 307 - 315. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 K. R. Brunt, M. R. Tsuji, J. H. Lai, R. T. Kinobe, W. Durante, W. C. Claycomb, C. A. Ward, and L. G. Melo Heme Oxygenase-1 Inhibits Pro-Oxidant Induced Hypertrophy in HL-1 Cardiomyocytes Experimental Biology and Medicine, May 1, 2009; 234(5): 582 - 594. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. T. Coughlan, D. R. Thorburn, S. A. Penfold, A. Laskowski, B. E. Harcourt, K. C. Sourris, A. L.Y. Tan, K. Fukami, V. Thallas-Bonke, P. P. Nawroth, et al. RAGE-Induced Cytosolic ROS Promote Mitochondrial Superoxide Generation in Diabetes J. Am. Soc. Nephrol., April 1, 2009; 20(4): 742 - 752. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 B. R. DeGeorge Jr, E. Gao, M. Boucher, L. E. Vinge, J. S. Martini, P. W. Raake, J. K. Chuprun, D. M. Harris, G. W. Kim, S. Soltys, et al. Targeted Inhibition of Cardiomyocyte Gi Signaling Enhances Susceptibility to Apoptotic Cell Death in Response to Ischemic Stress Circulation, March 18, 2008; 117(11): 1378 - 1387. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 Z. P. Shaik, E. K. Fifer, and G. Nowak Akt activation improves oxidative phosphorylation in renal proximal tubular cells following nephrotoxicant injury Am J Physiol Renal Physiol, February 1, 2008; 294(2): F423 - F432. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 X. Liu, J. A. Simpson, K. R. Brunt, C. A. Ward, S. R. R. Hall, R. T. Kinobe, V. Barrette, M. Y. Tse, S. C. Pang, A. S. Pachori, et al. Preemptive heme oxygenase-1 gene delivery reveals reduced mortality and preservation of left ventricular function 1 yr after acute myocardial infarction Am J Physiol Heart Circ Physiol, July 1, 2007; 293(1): H48 - H59. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
L. Villacorta, J. Zhang, M. T. Garcia-Barrio, X.-l. Chen, B. A. Freeman, Y. E. Chen, and T. Cui Nitro-linoleic acid inhibits vascular smooth muscle cell proliferation via the Keap1/Nrf2 signaling pathway Am J Physiol Heart Circ Physiol, July 1, 2007; 293(1): H770 - H776. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 K. Ito, G. Caramori, and I. M. Adcock Therapeutic Potential of Phosphatidylinositol 3-Kinase Inhibitors in Inflammatory Respiratory Disease J. Pharmacol. Exp. Ther., April 1, 2007; 321(1): 1 - 8. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A.-L. Levonen, M. Inkala, T. Heikura, S. Jauhiainen, H.-K. Jyrkkanen, E. Kansanen, K. Maatta, E. Romppanen, P. Turunen, J. Rutanen, et al. Nrf2 Gene Transfer Induces Antioxidant Enzymes and Suppresses Smooth Muscle Cell Growth In Vitro and Reduces Oxidative Stress in Rabbit Aorta In Vivo Arterioscler Thromb Vasc Biol, April 1, 2007; 27(4): 741 - 747. [Abstract] [Full Text] [PDF]
|
|