RNA interference elucidates the role of focal adhesion kinase in HLA class I-mediated focal adhesion complex formation and proliferation in human endothelial cells.
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.
Jin
Yi-Ping
YP
Department of Pathology, David Geffen School of Medicine, University of California-Los Angeles, Los Angeles, CA 90095, USA.
Korin
Yael
Y
Zhang
Xiaohai
X
Jindra
Peter T
PT
Rozengurt
Enrique
E
Reed
Elaine F
EF
D000199:Actins / Q000378:metabolism; D049109:Cell Proliferation; D002470:Cell Survival; D004730:Endothelium, Vascular / Q000166:cytology / Q000201:enzymology / Q000276:immunology*; D051416:Focal Adhesion Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000502:physiology*; D022001:Focal Adhesions / Q000187:drug effects / Q000235:genetics; D015395:Histocompatibility Antigens Class I / Q000276:immunology*; D006801:Humans; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D010766:Phosphorylation; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000494:pharmacology; D017468:Receptors, Fibroblast Growth Factor / Q000378:metabolism; D019061:src-Family Kinases / Q000378:metabolism
D000199:Actins; D015395:Histocompatibility Antigens Class I; D034741:RNA, Small Interfering; D017468:Receptors, Fibroblast Growth Factor; D019869:Phosphatidylinositol 3-Kinases; D051416:Focal Adhesion Protein-Tyrosine Kinases; D019061:src-Family Kinases; D051057:Proto-Oncogene Proteins c-akt