title: Mitogen-activated protein kinase activation mediates PDGF-directed migration of RPE cells.
abstract: Growth factor-directed migration is a critical component of the wound healing response although little is known about the signaling pathways involved. We examined the effect of inhibiting the mitogen-activated protein kinase (MAPK) pathway on platelet-derived growth factor (PDGF) and fibronectin-induced cell migration of human retinal pigment epithelial (RPE) cells. Using transwell cell-culture chambers, the effect of PDGF-BB (10-50 ng/ml) and fibronectin on components of migration was measured with or without the MAPK pathway inhibitor PD98059 (10-30 microM) MAPK activation of serum-starved cells by PDGF-BB was demonstrated by an immunoprecipitation/kinase assay and by immunohistochemistry using antibody specific for phosphorylated MAPK. PDGF-BB (10 ng/ml) stimulated MAPK activity in RPE (10 min) and its nuclear localization (1 h). PD98059 inhibited the activation of MAPK by PDGF-BB or serum. PDGF-BB stimulated RPE chemokinesis, chemotaxis, and haptotaxis; chemokinesis was additively increased and chemotaxis synergistically increased by the presence of a fibronectin substratum. PD98059 potently inhibited fibronectin-induced haptotaxis and PDGF-BB-induced chemotaxis but inhibited chemokinesis only at higher PDGF-BB (50 ng/ml) concentrations in the presence of fibronectin substratum. These results demonstrate that MAPK is critically involved in multiple components of RPE migration in vitro and suggest the potential of targeting MAPK to inhibit RPE migration in vivo.
authors.affiliation: Department of Pathology, University of Southern California School of Medicine, Los Angeles 90033, USA.
authors.forename: D R
authors.initials: DR
authors.lastname: Hinton
authors.forename: S
authors.initials: S
authors.lastname: He
authors.forename: K
authors.initials: K
authors.lastname: Graf
authors.forename: D
authors.initials: D
authors.lastname: Yang
authors.forename: W A
authors.initials: WA
authors.lastname: Hsueh
authors.forename: S J
authors.initials: SJ
authors.lastname: Ryan
authors.forename: R E
authors.initials: RE
authors.lastname: Law
mesh_terms: D000077214:Becaplermin; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D002460:Cell Line; D002465:Cell Movement / Q000187:drug effects; D002467:Cell Nucleus / Q000201:enzymology; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005353:Fibronectins / Q000494:pharmacology; D005419:Flavonoids / Q000494:pharmacology; D006801:Humans; D007700:Kinetics; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D010766:Phosphorylation; D010857:Pigment Epithelium of Eye / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D010982:Platelet-Derived Growth Factor / Q000494:pharmacology*; D020574:Proto-Oncogene Proteins c-sis
chemical_list: D004791:Enzyme Inhibitors; D005353:Fibronectins; D005419:Flavonoids; D010982:Platelet-Derived Growth Factor; D020574:Proto-Oncogene Proteins c-sis; D000077214:Becaplermin; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one