[Abeta(25-35) and ginsenoside Rb1 influence on the expression of GSK-3beta, CDK-5 and PP2A in differentiated neural stem cells of rats].

Objective: To explore the expression of GSK-3beta, CDK-5 and PP2A and the regulation of them by Abeta(25-35) and ginsenoside Rb1 after neural stem cells (NSCs) are transformed into neurons.

Methods: To culture NSCs from the dentate gyrus of newborn rats(24 h) hippocampus in vitro. NSCs of the third passage were induced towards neurons; the expressions of GSK-3beta(pTyr279,216), PP2A and the regulation of them by Abeta(25-35) and ginsenoside Rb1 were tested by the immunofluorescence cytochemical staining after NSCs had been induced for one week; The expressions of GSK-3beta, CDK-5, PP2A and the regulation of them by Abeta(25-35) and ginsenoside Rb1 were detected with RT-PCR.

Results: Immunofluorescence cytochemisty showed that neural cells from NSCs which had been differentiated after one week could express GSK-3j (pTyr279,216)and PP2A. Abeta(25-35) could enhance the expression of GSK-3beta(pTyr279,216), meanwhile it also restrained the expression of PP2A. Moreover ginsenoside Rb1 could reverse the affect of Abeta(25-35). RT-PCR found that neural stem cells which had been differentiated after one week could express GSK-3beta, CDK-5, PP2A . The expression of GSK-3beta and CDK-5 rose up and the expression of PP2A weakened when they were treated by Abeta(25-35). However, the effect of Abeta(25-35) was restrained when they were pretreated by ginsenoside Rb1.

Conclusion: These observations indicated that NSCs which were cultured and induced in vitro can express GSK-3beta, CDK-5 and PP2A; moreover Abeta(25-35) and ginsenoside Rb1 can regulate the expressions of GSK-3beta, CDK-5 and PP2A. It hints that cells which differentiated from neural stem cells in vitro have protein phosphorylation regulation system of normal cells.