title: Low-Rac1 activity downregulates MC3T3-E1 osteoblastic cell motility on a nanoscale topography prepared on polystyrene substrates in vitro.
abstract: Surface roughness affects various cell activities, including osteoblast motility, which may have an effect on bone regeneration. Defective cell signaling, which is associated with the slow motility of osteoblasts on a substrate with rough topology at nanometer dimensions (Ra = 123.8 ± 29.1 nm), was studied. Osteoblasts grown on the rough surface at nanometer dimensions showed the high activities of small GTPase RhoA and Rho-associated kinase (ROCK) on the rough surface at nanometer dimensions and downregulated Rac1 activity compared to the smooth surface. The inhibition of ROCK in the cells with Y-27632, a specific ROCK inhibitor, reversed the low-cell motility. In addition, the transfection of constitutively active Rac1 reversed the low-cell motility. However, Rac1 inhibition abolished the reversal of low-cell motility induced by ROCK inhibition. These results indicate that upregulated RhoA/ROCK activity suppresses Rac1 activity to decrease the motility of osteoblasts on a rough surface at nanometer dimensions, and the low motility of osteoblasts on a rough surface at nanometer dimensions can be reversed by ROCK inhibition.
authors.affiliation: Laboratory for the Study of Molecular Biointerfaces, Department of Oral Histology and Developmental Biology, School of Dentistry and Dental Research Institute, Seoul National University, Seoul, Republic of Korea.
authors.forename: Liling
authors.initials: L
authors.lastname: Zheng
authors.forename: Hyun-Man
authors.initials: HM
authors.lastname: Kim
mesh_terms: D000818:Animals; D002460:Cell Line; D002465:Cell Movement / Q000187:drug effects*; D049109:Cell Proliferation / Q000187:drug effects; D015536:Down-Regulation / Q000187:drug effects*; D051379:Mice; D008954:Models, Biological; D049329:Nanostructures / Q000737:chemistry*; D010006:Osteoblasts / Q000166:cytology* / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D011137:Polystyrenes / Q000737:chemistry / Q000494:pharmacology*; D015398:Signal Transduction / Q000187:drug effects; D013499:Surface Properties / Q000187:drug effects; D020830:rac1 GTP-Binding Protein / Q000378:metabolism*; D054460:rho-Associated Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism
chemical_list: D011137:Polystyrenes; D054460:rho-Associated Kinases; D020830:rac1 GTP-Binding Protein