Prolonged Alzheimer-like tau hyperphosphorylation induced by simultaneous inhibition of phosphoinositol-3 kinase and protein kinase C in N2a cells.
Co-injection of wortmannin (inhibitor of phosphatidylinositol-3 kinase, PI3K) and GF109203X (inhibitor of protein kinase C, PKC) into the rat brain was found to induce spatial memory deficiency and enhance tau hyperphosphorylation in the hippocampus of rat brain. To establish a cell model with durative Alzheimer-like tau hyperphosphorylation in this study, we treated N2a neuroblastoma cells with wortmannin and GF109203X separately and simultaneously, and measured the glycogen synthase kinase 3 (GSK-3) activity by gamma-32P-labeling and the level of tau phosphorylation by Western blotting. It was found that the application of wortmannin alone only transitorily increased the activity of GSK-3 (about 1 h) and the level of tau hyperphosphorylation at Ser396/Ser404 and Ser199/Ser202 sites (no longer than 3 h); however, a prolonged and intense activation of GSK-3 (over 12 h) and enhanced tau hyperphosphorylation (about 24 h) were observed when these two selective kinase inhibitors were applied together. We conclude that the simultaneous inhibition of PI3K and PKC can induce GSK-3 overactivation, and further strengthen and prolong the Alzheimer-like tau hyperphosphorylation in N2a cells, suggesting the establishment of a cell model with early pathological events of Alzheimer's disease.
Xu
Guo-Gang
GG
Department of Pathophysiology, Institute of Neuroscience, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.
Deng
Yan-Qiu
YQ
Liu
Shi-Jie
SJ
Li
Hong-Lian
HL
Wang
Jian-Zhi
JZ
D000544:Alzheimer Disease / Q000378:metabolism*; D000682:Amyloid / Q000378:metabolism; D000730:Androstadienes / Q000494:pharmacology; D000818:Animals; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D038362:Glycogen Synthase Kinase 3 / Q000378:metabolism*; D007211:Indoles / Q000494:pharmacology; D008301:Maleimides / Q000494:pharmacology; D009447:Neuroblastoma / Q000378:metabolism*; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D000081082:Phosphoinositide-3 Kinase Inhibitors; D010766:Phosphorylation / Q000187:drug effects; D011493:Protein Kinase C / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D051381:Rats; D000077191:Wortmannin; D016875:tau Proteins / Q000378:metabolism*
D000682:Amyloid; D000730:Androstadienes; D004791:Enzyme Inhibitors; D038362:Glycogen Synthase Kinase 3; D007211:Indoles; D008301:Maleimides; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D011493:Protein Kinase C; D000077191:Wortmannin; D016875:tau Proteins; C070515:bisindolylmaleimide I