title: The behavior of endothelial cells on polyurethane nanocomposites and the associated signaling pathways.
abstract: A series of nanocomposites from polyurethane (PU) incorporated with various low concentrations (17.4-174 ppm) of gold nanoparticles (approximately 5 nm) (denoted "PU-Au") were used as a model system to study the mechanisms that influenced endothelial cell (EC) migration on biomaterial surfaces. The migration rate of ECs on the PU-Au nanocomposites was determined by a real-time image system. It was found that ECs had the highest migration rate on the nanocomposite containing 43.5 ppm of gold ("PU-Au 43.5 ppm"). The high EC migration rate was associated with increased levels of endothelial nitric oxide synthase (eNOS) and phosphorylated-Akt (p-Akt) expressed by ECs cultured on PU-Au. The inductions of both eNOS and p-Akt on PU-Au were abolished by the addition of LY294002 (PI3K inhibitor), suggesting that these cellular events may be regulated through the PI3K signaling pathway. Using a biotinylated VEGF-165 that recognizes VEGF receptors and by FACS analysis, slightly higher expression of VEGF receptors for ECs on PU-Au was also demonstrated. Phalloidin staining showed that actin appeared as a circumferential band surrounding each cell on tissue culture polystyrene, whereas on PU-Au, especially on PU-Au 43.5 ppm, the cells had their margin spread out and extend processes with stress fibers in the protruding lamellipodia. Moreover, the higher EC migration rate on PU-Au 43.5 ppm was suppressed by LY294002. The higher protein expression of focal adhesion kinase (FAK) on PU-Au 43.5 ppm was observed in FAK-GFP transfected ECs. It was concluded that PU-Au nanocomposites activated FAK and the PI3K/Akt signaling pathway in ECs, leading to proliferation and migration of ECs on these surfaces.
authors.affiliation: Center of Tissue Engineering and Stem Cells Research, National Chung Hsing University, Taichung, Taiwan, ROC.
authors.forename: Huey-Shan
authors.initials: HS
authors.lastname: Hung
authors.forename: Chia-Ching
authors.initials: CC
authors.lastname: Wu
authors.forename: Shu
authors.initials: S
authors.lastname: Chien
authors.forename: Shan-hui
authors.initials: SH
authors.lastname: Hsu
mesh_terms: D000199:Actins / Q000378:metabolism; D000818:Animals; D002417:Cattle; D002465:Cell Movement / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000166:cytology* / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D005455:Fluorescent Antibody Technique; D051416:Focal Adhesion Protein-Tyrosine Kinases / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000378:metabolism; D008954:Models, Biological; D053761:Nanocomposites; D009569:Nitric Oxide / Q000378:metabolism; D052250:Nitric Oxide Synthase Type III / Q000378:metabolism; D010641:Phenotype; D011140:Polyurethanes / Q000494:pharmacology*; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D040262:Receptors, Vascular Endothelial Growth Factor / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects*; D022502:Stress Fibers / Q000187:drug effects / Q000201:enzymology
chemical_list: D000199:Actins; D011140:Polyurethanes; D049452:Green Fluorescent Proteins; D009569:Nitric Oxide; D052250:Nitric Oxide Synthase Type III; D040262:Receptors, Vascular Endothelial Growth Factor; D051416:Focal Adhesion Protein-Tyrosine Kinases; D051057:Proto-Oncogene Proteins c-akt