title: High glucose-mediated oxidative stress impairs cell migration.
abstract: Deficient wound healing in diabetic patients is very frequent, but the cellular and molecular causes are poorly defined. In this study, we evaluate the hypothesis that high glucose concentrations inhibit cell migration. Using CHO.K1 cells, NIH-3T3 fibroblasts, mouse embryonic fibroblasts and primary skin fibroblasts from control and diabetic rats cultured in 5 mM D-glucose (low glucose, LG), 25 mM D-glucose (high glucose, HG) or 25 mM L-glucose medium (osmotic control--OC), we analyzed the migration speed, protrusion stability, cell polarity, adhesion maturation and the activity of the small Rho GTPase Rac1. We also analyzed the effects of reactive oxygen species by incubating cells with the antioxidant N-Acetyl-Cysteine (NAC). We observed that HG conditions inhibited cell migration when compared to LG or OC. This inhibition resulted from impaired cell polarity, protrusion destabilization and inhibition of adhesion maturation. Conversely, Rac1 activity, which promotes protrusion and blocks adhesion maturation, was increased in HG conditions, thus providing a mechanistic basis for the HG phenotype. Most of the HG effects were partially or completely rescued by treatment with NAC. These findings demonstrate that HG impairs cell migration due to an increase in oxidative stress that causes polarity loss, deficient adhesion and protrusion. These alterations arise, in large part, from increased Rac1 activity and may contribute to the poor wound healing observed in diabetic patients.
authors.affiliation: Department of Morphological Sciences, Institute of Basic Health Science, Federal University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil.
authors.forename: Marcelo L
authors.initials: ML
authors.lastname: Lamers
authors.forename: Maíra E S
authors.initials: ME
authors.lastname: Almeida
authors.forename: Miguel
authors.initials: M
authors.lastname: Vicente-Manzanares
authors.forename: Alan F
authors.initials: AF
authors.lastname: Horwitz
authors.forename: Marinilce F
authors.initials: MF
authors.lastname: Santos
mesh_terms: D000818:Animals; D002460:Cell Line; D002465:Cell Movement / Q000187:drug effects*; D016764:Cell Polarity / Q000187:drug effects; D002478:Cells, Cultured; D005947:Glucose / Q000494:pharmacology*; D051379:Mice; D041681:NIH 3T3 Cells; D018384:Oxidative Stress / Q000187:drug effects*; D051381:Rats; D017382:Reactive Oxygen Species / Q000378:metabolism; D020830:rac1 GTP-Binding Protein / Q000378:metabolism; D020742:rhoA GTP-Binding Protein / Q000378:metabolism
chemical_list: D017382:Reactive Oxygen Species; D020830:rac1 GTP-Binding Protein; D020742:rhoA GTP-Binding Protein; D005947:Glucose