Peptide-Mediated Disruption of Calmodulin–Cyclin E Interactions Inhibits Proliferation of Vascular Smooth Muscle Cells and Neointima Formation

• Published in: Circulation research Vol. 108; no. 9; pp. 1053 - 1062
• Main Authors: Hui, Sonya, Choi, Jaehyun, Zaidi, Syed, Momen, Abdul, Steinbach, Sarah K, Sadi, Al-Muktafi, Ban, Kiwon, Husain, Mansoor
• Format: Journal Article
• Language: English
• Published: Hagerstown, MD American Heart Association, Inc 29-04-2011; Lippincott Williams & Wilkins
• Subjects: Animals; Aorta - cytology; Binding Sites - physiology; Biological and medical sciences; Blood Proteins - pharmacology; Calmodulin - chemistry; Calmodulin - metabolism; Coronary Restenosis - metabolism; Coronary Restenosis - pathology; Coronary Restenosis - prevention & control; Cyclin E - chemistry; Cyclin E - metabolism; Cyclin-Dependent Kinase 2 - metabolism; Extracellular Matrix - drug effects; Extracellular Matrix - metabolism; Fundamental and applied biological sciences. Psychology; Human immunodeficiency virus 1; Hydrophobic and Hydrophilic Interactions; Mice; Muscle, Smooth, Vascular - cytology; Muscle, Smooth, Vascular - drug effects; Muscle, Smooth, Vascular - metabolism; Neointima - drug therapy; Neointima - metabolism; Neointima - pathology; Peptides - chemical synthesis; Peptides - genetics; Peptides - pharmacology; Phosphorylation - drug effects; Phosphorylation - physiology; Protein Kinases - metabolism; S Phase - drug effects; S Phase - physiology; Vertebrates: cardiovascular system; Cell proliferation; Peptides; Interaction; Cyclin; Smooth muscle; Restenosis; Vertebrata; Mammalia; cyclin E/CDK2; Cell cycle; Circulatory system; vascular smooth muscle cell; Formation; Calmodulin
• ISSN: 0009-7330; 1524-4571
• DOI: 10.1161/CIRCRESAHA.110.239483

RATIONALE:Cell cycle progression in vascular smooth muscle cells (VSMCs) is a therapeutic target for restenosis.
OBJECTIVE:Having discovered that calmodulin (CaM)-dependent cyclin E/CDK2 activity underlies Ca-sensitive G1-to-S phase transitions in VSMCs, we sought to explore the physiological importance of the CaM–cyclin E interaction.
METHODS AND RESULTS:A peptide based on the CaM binding sequence (CBS) of cyclin E was designed to interfere with CaM–cyclin E binding. Compared with control peptides, CBS blocked activating Thr160 phosphorylation of CDK2, decreased basal cyclin E/CDK2 activity, and eliminated Ca-sensitive cyclin E/CDK2 activity in nuclear extracts from mouse VSMCs. Nucleofection with CBS, or treatment with CBS conjugated to the HIV-1 TAT protein transduction domain to improve bioavailability, inhibited G1-to-S cell cycle progression in a dose-dependent manner. These effects were not observed with control peptides. TAT-CBS inhibited H-thymidine incorporation in primary human aortic SMCs (HA-SMCs) in vitro, manifested greater transduction into HA-SMCs compared with endothelial cells in vitro, and limited decreased SM22α expression, neointima formation, and medial thickening without affecting collagen deposition or reendothelialization in a mouse model of carotid artery injury in vivo. The antiproliferative effects of CBS remained evident in mouse embryonic fibroblasts derived from wild-type mice but not cyclin E1/E2 double knockout mice.
CONCLUSIONS:A synthetic peptide designed to disrupt CaM–cyclin E binding inhibits Ca/CaM-dependent CDK2 activity, cell cycle progression, and proliferation in VSMCs and limits arterial remodeling following injury. Importantly, this effect appears to be cyclin E–dependent and may form the basis of a potentially novel therapeutic approach for restenosis.