The Antiangiogenic Activity of Cleaved High Molecular Weight Kininogen Is Mediated through Binding to Endothelial Cell Tropomyosin

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 99; no. 19; pp. 12224 - 12229
• Main Authors: Zhang, Jing-Chuan, Doñate, Fernando, Qi, Xiaoping, Ziats, Nicholas P., Juarez, Jose C., Mazar, Andrew P., Pang, Yuan-Ping, McCrae, Keith R.
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences 17.09.2002; National Acad Sciences
• Subjects: Allantois - blood supply; Allantois - drug effects; Angiogenesis; Angiogenesis Inhibitors - metabolism; Angiogenesis Inhibitors - pharmacology; Animals; Antibodies; Antibodies, Monoclonal - pharmacology; Apoptosis; Apoptosis - drug effects; Base Sequence; Biological Sciences; Blood vessels; Cell growth; Cells; Cells, Cultured; Cellular biology; Chick Embryo; Chorion - blood supply; Chorion - drug effects; Cultured cells; DNA; DNA, Complementary - genetics; Endothelial cells; Endothelium, Vascular - cytology; Endothelium, Vascular - drug effects; Endothelium, Vascular - metabolism; Human umbilical vein endothelial cells; Humans; Kininogen, High-Molecular-Weight - genetics; Kininogen, High-Molecular-Weight - metabolism; Kininogen, High-Molecular-Weight - pharmacology; Kininogens; Neovascularization, Physiologic - drug effects; Protein Binding; Proteins; Receptors; Recombinant Proteins - genetics; Recombinant Proteins - metabolism; Recombinant Proteins - pharmacology; Tropomyosin - antagonists & inhibitors; Tropomyosin - metabolism
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.192668299

Conformationally altered proteins and protein fragments derived from the extracellular matrix and hemostatic system may function as naturally occurring angiogenesis inhibitors. One example of such a protein is cleaved high molecular weight kininogen (HKa). HKa inhibits angiogenesis by inducing apoptosis of proliferating endothelial cells, effects mediated largely by HKa domain 5. However, the mechanisms underlying the antiangiogenic activity of HKa have not been characterized, and its binding site on proliferating endothelial cells has not been defined. Here, we report that the induction of endothelial cell apoptosis by HKa, as well as the antiangiogenic activity of HKa in the chick chorioallantoic membrane, was inhibited completely by antitropomyosin monoclonal antibody TM-311. TM-311 also blocked the high-affinity Zn2+-dependent binding of HKa to both purified tropomyosin and proliferating endothelial cells. Confocal microscopic analysis of endothelial cells stained with monoclonal antibody TM-311, as well as biotin labeling of cell surface proteins on intact endothelial cells, revealed that tropomyosin exposure was enhanced on the surface of proliferating cells. These studies demonstrate that the antiangiogenic effects of HKa depend on high-affinity binding to endothelial cell tropomyosin.