title: [ApoE4 increases glycogen synthase kinase 3β expression and Tau phosphorylation in U87 cells].
abstract: OBJECTIVE
  To explore the relations among apolipoprotein E4, Tau protein and glycogen synthase kinase 3β (GSK-3β).
  
  
  METHODS
  U87 cells were transfected with pIRES-EGFP (control) or the recombinant plasmids ApoE4/pIRES-EGFP or ApoE3/pIRES-EGFP, and the expression levels of p-Tau/Tau and GSK-3β in the cells were examined with Western blotting. To further confirm the effect of ApoE on GSK-3β and p-Tau expressions, a short interfering RNA (siRNA) targeting ApoE (ApoE-siRNA) was transfected into U87 cells via Lipofectamine 2000 and the protein expressions were examined 24 h later.
  
  
  RESULTS
  Compared with those in the control group, the expressions levels of both GSK-3β and p-Tau/Tau increased significantly in the cells transfected with ApoE4 and ApoE3 plasmids (P<0.01), and the ApoE4 plasmid produced a more potent effect than the ApoE3 plasmid on the protein expressions (P<0.01). ApoE knockdown resulted in significantly reduced expressions of GSK-3β (P<0.001) and p-Tau (P<0.01) in the cells.
  
  
  CONCLUSIONS
  ApoE4 can enhance Tau phosphorylation though upregulating GSK-3β, which sheds light on a new role of ApoE4 in Alzheimer's disease.
authors.affiliation: Department of Neurobiology, College of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, China.E-mail: 381980753@qq.com.
authors.forename: Yan-Jie
authors.initials: YJ
authors.lastname: He
authors.forename: Pei-Ru
authors.initials: PR
authors.lastname: Wei
authors.forename: Qiao-Yan
authors.initials: QY
authors.lastname: Wu
authors.forename: Xin-Yu
authors.initials: XY
authors.lastname: Zhang
authors.forename: Xing-Mei
authors.initials: XM
authors.lastname: Zhang
authors.forename: Xiao-Jia
authors.initials: XJ
authors.lastname: Liu
authors.forename: Fang
authors.initials: F
authors.lastname: Wang
mesh_terms: D000544:Alzheimer Disease / Q000235:genetics; D053318:Apolipoprotein E3 / Q000235:genetics; D053327:Apolipoprotein E4 / Q000235:genetics*; D002460:Cell Line; D020868:Gene Silencing; D000071679:Glycogen Synthase Kinase 3 beta / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D010766:Phosphorylation; D034741:RNA, Small Interfering / Q000235:genetics; D014162:Transfection; D016875:tau Proteins / Q000378:metabolism*
chemical_list: D053318:Apolipoprotein E3; D053327:Apolipoprotein E4; D034741:RNA, Small Interfering; D016875:tau Proteins; D000071679:Glycogen Synthase Kinase 3 beta