TY - JOUR
T1 - FXR promotes endothelial cell motility through coordinated regulation of FAK and MMP-9
AU - Das, Amitava
AU - Yaqoob, Usman
AU - Mehta, Dolly
AU - Shah, Vijay H.
N1 - Copyright:
Copyright 2009 Elsevier B.V., All rights reserved.
PY - 2009/4/1
Y1 - 2009/4/1
N2 - OBJECTIVE: Farnesoid X Receptor (FXR) mediates important signaling functions of bile acids in diverse cell types including those residing in the vascular wall. Indeed, recent work has identified FXR as a potential regulator of vascular structure and function in part through transcriptional activation of MMP-9. However, the signal transduction pathways linking bile acids to changes in actin cytoskeleton that are responsible for bile acid-induced vascular cell migration remain unexplored. METHODS AND RESULTS: The FXR agonist and prototypical bile acid, chenodeoxycholic acid (CDCA), significantly increased endothelial cell (EC) motility, as analyzed by time lapse video microscopy, and tube formation, an in vitro correlate for angiogenesis. Increased cell motility was associated with prominent increases in focal adhesion (FA) plaques and was inhibited by FXR or MMP-9 siRNA, indicating a FXR-MMP-9-dependency of this signaling pathway. Mechanistically, incubation of cells with CDCA was associated with phosphorylation of a key FA protein, Focal Adhesion Kinase (FAK) at Y397 but not at Y576/577, or Y925. Studies using a site-specific phosphorylation mutant (phosphodeficient) of FAK revealed that FAK phosphorylation at tyrosine residue -397 was required for CDCA induced activation of the downstream FA assembly protein, paxillin. Lastly, siRNA-based silencing of FAK as well as phosphodeficient FAK mutant inhibited CDCA induced upregulation of MMP-9, cell motility, and vascular tube formation. CONCLUSION: Thus, this study demonstrates a pivotal role for FAK in the process of FXR-induced and MMP-9-dependent EC motility and vascular tube formation.
AB - OBJECTIVE: Farnesoid X Receptor (FXR) mediates important signaling functions of bile acids in diverse cell types including those residing in the vascular wall. Indeed, recent work has identified FXR as a potential regulator of vascular structure and function in part through transcriptional activation of MMP-9. However, the signal transduction pathways linking bile acids to changes in actin cytoskeleton that are responsible for bile acid-induced vascular cell migration remain unexplored. METHODS AND RESULTS: The FXR agonist and prototypical bile acid, chenodeoxycholic acid (CDCA), significantly increased endothelial cell (EC) motility, as analyzed by time lapse video microscopy, and tube formation, an in vitro correlate for angiogenesis. Increased cell motility was associated with prominent increases in focal adhesion (FA) plaques and was inhibited by FXR or MMP-9 siRNA, indicating a FXR-MMP-9-dependency of this signaling pathway. Mechanistically, incubation of cells with CDCA was associated with phosphorylation of a key FA protein, Focal Adhesion Kinase (FAK) at Y397 but not at Y576/577, or Y925. Studies using a site-specific phosphorylation mutant (phosphodeficient) of FAK revealed that FAK phosphorylation at tyrosine residue -397 was required for CDCA induced activation of the downstream FA assembly protein, paxillin. Lastly, siRNA-based silencing of FAK as well as phosphodeficient FAK mutant inhibited CDCA induced upregulation of MMP-9, cell motility, and vascular tube formation. CONCLUSION: Thus, this study demonstrates a pivotal role for FAK in the process of FXR-induced and MMP-9-dependent EC motility and vascular tube formation.
KW - Angiogenesis
KW - Bile acids
KW - FAK
KW - FXR
KW - MMP-9
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U2 - 10.1161/ATVBAHA.108.182725
DO - 10.1161/ATVBAHA.108.182725
M3 - Article
C2 - 19150878
AN - SCOPUS:63449135394
SN - 1079-5642
VL - 29
SP - 562
EP - 570
JO - Arteriosclerosis, thrombosis, and vascular biology
JF - Arteriosclerosis, thrombosis, and vascular biology
IS - 4
ER -