Characteristic response of astrocytes to plasminogen

摘要

The treatment of astrocytes with rat plasminogen (PLGn) led to a significant increase in transforming growth factor beta3 (TGFbeta3) in the conditioned medium (CM). In surveying signaling molecules that responds to PLGn, we found that phos-phorylation of Akt is promoted. The pretreatment of astrocytes with an Akt inhibitor prior to PLGn stimulation resulted in a significant decrease in Akt phosphorylation as well as TGFbeta3 amounts in the CM. Further survey revealed that phosphatidylinositol 3 kinase (PI3K) activity is closely associated with TGFbeta3 production/secretion in astrocytes. In fact, PI3K inhibitor clearly depressed the phosphorylation of Akt. These results suggest that PLGn facilitates the production/secretion of TGFbeta3 in astrocytes through a signaling cascade including PI3K and Akt.