Vascular Endothelial Growth Factor Promotes Mesenchymal Stem Cells Adhering and Spreading

Abstract: Mesenchymal stem cells (MSCs)， which have the pluripotent ability， can migrate directionally toward chemotactic agents and cytokines in vitro or show a tropism to injured brain or gliomas. Cell adhering is the fisrt step for cell migration and the understanding of cell adhesion could be helpful for the study of cell migration. The assembly and distribution of focal adhesions (FAs) and the arrangement of F-actin cytoskeletons are involved in the process of cell adhesion. With the plating time extended， the adhering cells became spreading and formed small focal complexes (FXs) to mature big FAs. F-actin assembled as circular bundles at the early stage and then formed stress fibres that made the cells possess polarity. The tyrosine phosphorylation activation of Y397-FAK and Y31/Y118-paxillin (both proteins could regulate the assembly of FAs and the arrangement of F-actin cytoskeletons) changed during the spreading. The activation of Y397-FAK increased while the FAs were assembling; then the activation decreased when the FAs were mature. Activated FAK could phosphorylate Y31/Y118-paxillin which participates in regulating the remodelling of F-actin cytoskeleton. Under the treatment of VEGF， cells formed adhesions faster and were more spreading. The maturation of FAs and cytoskeletons needs less time. Otherwise， the FAs were slender and with more quantity. Collectively， these results demonstrated that VEGF could regulate MSCs adhesion and spreeding including the formation of FAs and the arrangement of F-actin cytoskeletons. This suggests that VEGF may regulate the migration of MSCs through modulating the FAs and cytoskeletons. And our research provides rationale for the study of cell migration.

CSTR: 32200.14.cjcb.2012.10.0002