Blockade of integrin beta3-FAK signaling pathway activated by osteopontin inhibits neointimal formation after balloon injury.
BACKGROUND
Osteopontin (OPN) promotes the migration and adhesion of vascular smooth muscle cells (VSMCs) through cell surface receptor, integrin beta3. In order to elucidate the signaling pathway by which OPN is involved in neointimal formation, we focused on integrin beta3-focal adhesion kinase (FAK) upon VSMC migration.


METHODS
The integrin beta3 and FAK expression in VSMC and in neointima was detected by Western blot and immunohistochemistry staining. FAK phosphorylation induced by OPN was verified using a linear OPN 13 peptide containing RGD motif and anti-OPN antibody. The role of integrin beta3-FAK pathway in VSMC adhesion and migration induced with OPN was tested by the overexpression of FAK-related nonkinase and integrin beta3 cytoplasmic domain.


RESULTS
The results showed that OPN increased integrin beta3 expression and induced rapid and transient FAK phosphorylation. Inhibition of the phosphorylation of FAK significantly suppressed VSMC migration induced by OPN. Similarly, blockade of the interaction of integrin beta3 with OPN inhibited VSMC adhesion induced by OPN. The experiment, in vivo, demonstrated that OPN expression level was consistent with neointimal thickening. Administration of anti-OPN antibody for blocking OPN function suppressed integrin beta3 and FAK expression induced by balloon injury, and neointimal thickening was inhibited.


CONCLUSIONS
These data indicate that integrin beta3-FAK signaling modulates OPN-induced VSMC migration during neointimal formation.
Han
Mei
M
Department of Biochemistry and Molecular Biology, Hebei Medical University, Shijiazhuang, China.
Wen
Jin-Kun
JK
Zheng
Bin
B
Liu
Zhimin
Z
Chen
Yunhui
Y
D000818:Animals; D000906:Antibodies; D001011:Aorta / Q000378:metabolism; D020212:Carotid Artery Injuries / Q000201:enzymology / Q000209:etiology / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control*; D002404:Catheterization / Q000009:adverse effects*; D002448:Cell Adhesion; D002465:Cell Movement; D002478:Cells, Cultured; D004195:Disease Models, Animal; D051417:Focal Adhesion Kinase 1 / Q000378:metabolism*; D039661:Integrin beta3 / Q000235:genetics / Q000378:metabolism*; D009131:Muscle, Smooth, Vascular / Q000201:enzymology / Q000378:metabolism*; D032389:Myocytes, Smooth Muscle / Q000201:enzymology / Q000378:metabolism*; D053495:Osteopontin / Q000276:immunology / Q000378:metabolism*; D010766:Phosphorylation; D011505:Protein-Tyrosine Kinases / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction; D013997:Time Factors; D014162:Transfection; D017539:Tunica Intima / Q000378:metabolism / Q000473:pathology
D000906:Antibodies; D039661:Integrin beta3; C506897:Spp1 protein, rat; D053495:Osteopontin; C113183:FAK-related nonkinase; D011505:Protein-Tyrosine Kinases; D051417:Focal Adhesion Kinase 1; C496052:Ptk2 protein, rat