This Article Full Text Full Text (PDF) Data Supplement All Versions of this Article: 26/9/2027    most recent 01.ATV.0000236204.37119.8dv1 Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Brunt, K. R. Articles by Melo, L. G. Search for Related Content PubMed PubMed Citation Articles by Brunt, K. R. Articles by Melo, L. G.

(Arteriosclerosis, Thrombosis, and Vascular Biology. 2006;26:2027.)
© 2006 American Heart Association, Inc.

Vascular Biology

Protection of Human Vascular Smooth Muscle Cells From H₂O₂-Induced Apoptosis Through Functional Codependence Between HO-1 and AKT

Keith R. Brunt; Keith K. Fenrich; Gholam Kiani; M. Yat Tse; Stephen C. Pang; Christopher A. Ward; Luis G. Melo

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.

Correspondence to Dr Luis G. Melo, Department of Physiology, Queen’s University, 18 Stuart St, Kingston, Ontario, K7L 4S7. Canada. 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.

Oxidative stress induces smooth muscle cell apoptosis in the atherosclerotic plaque, leading to plaque instability. Heme oxygenase-1 (HO-1) exerts anti-oxidant, anti-inflammatory, and anti-apoptotic effects in the vessel wall. Here we report that the cytoprotective effect of HO-1 against pro-oxidant–induced apoptosis is mediated through codependent interaction with the survival gene Akt.

Key Words: apoptosis • flow cytometry • mitochondrial membrane potential • oxidative stress • vascular smooth muscle cells

This article has been cited by other articles:

				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]