RNA Interference Elucidates the Role of Focal Adhesion Kinase in HLA Class I-Mediated Focal Adhesion Complex Formation and Proliferation in Human Endothelial Cells

• Published in: Journal of Immunology 2007-06, Vol.178 (12), p.7911-7922
• Main Authors: Jin, Yi-Ping, Korin, Yael, Zhang, Xiaohai, Jindra, Peter T, Rozengurt, Enrique, Reed, Elaine F
• Format: Article
• Language: English
• Subjects: Actins - metabolism; Cell Proliferation; Cell Survival; Endothelium, Vascular - cytology; Endothelium, Vascular - enzymology; Endothelium, Vascular - immunology; Focal Adhesion Protein-Tyrosine Kinases - antagonists & inhibitors; Focal Adhesion Protein-Tyrosine Kinases - genetics; Focal Adhesion Protein-Tyrosine Kinases - physiology; Focal Adhesions - drug effects; Focal Adhesions - genetics; Histocompatibility Antigens Class I - immunology; Humans; Phosphatidylinositol 3-Kinases - metabolism; Phosphorylation; Proto-Oncogene Proteins c-akt - metabolism; Receptors, Fibroblast Growth Factor - metabolism; RNA Interference; RNA, Small Interfering - pharmacology; src-Family Kinases - metabolism
• ISSN: 0022-1767; 1550-6606; 1365-2567
• DOI: 10.4049/jimmunol.178.12.7911

Ligation of class I molecules by anti-HLA Ab stimulates an intracellular signaling cascade resulting in endothelial cell (EC) survival and proliferation, and has been implicated in the process of chronic allograft rejection and transplant-associated vasculopathy. In this study, we used small interfering RNA blockade of focal adhesion kinase (FAK) protein to determine its role in class I-mediated organization of the actin cytoskeleton, cell survival, and cell proliferation in primary cultures of human aortic EC. Knockdown of FAK appreciably inhibited class I-mediated phosphorylation of Src at Tyr(418), p85 PI3K, and Akt at both Thr(308) and Ser(473) sites. FAK knockdown also reduced class I-mediated phosphorylation of paxillin at Try(118) and blocked class I-induced paxillin assembly into focal contacts. FAK small interfering RNA completely abrogated class I-mediated formation of actin stress fibers. Interestingly, FAK knockdown did not modify fibroblast growth factor receptor expression induced by class I ligation. However, FAK knockdown blocked HLA class I-stimulated cell cycle proliferation in the presence and absence of basic fibroblast growth factor. This study shows that FAK plays a critical role in class I-induced cell proliferation, cell survival, and focal adhesion assembly in EC and may promote the development of transplant-associated vasculopathy.