Effect of truncated-ApoE4 overexpression on tau phosphorylation in cultured N2a cells.
The carboxyl-terminal amino acids 272-299-truncated apoE4 (delta272-299) is the main fragments of apoE4 hydrolysate in neurons. The effects of truncated-ApoE4 (delta272-299) overexpression on tau phosphorylation in cultured N2a cells were investigated. The truncated-apoE4 (delta272-299) cDNA was subcloned into pEGFP-c3 to form recombinant pEGFP-T-apoE4. pEGFP-c3, pEGFP-T-apoE4 and pEGFP-apoE4 were transfected into N2a cells respectively by lipofectamine 2000 method. After 24--48 h, tau phosphorylation was detected by Western blot assay and glycogen synthase kinase-3 (GSK-3) activity by using GSK-3 activity assay. The results showed that the overexpression of both full length-apoE4 and truncated apoE4 fragments in N2a cells induced a dramatic increase in phosphorylation of tau at Ser202 sites and the activation of GSK-3 as compared with untransfected cells, most significantly in the cells transfected with pEGFP-T-apoE4 (P < 0.05). It was concluded that in vitro overexpression of truncated-ApoE4 (delta272-299) can result in tau hyperphosphorylation in N2a cells by activating GSK-3, suggesting truncated-ApoE4 (delta272-299) might contribute the pathogenesis of Alzheimer disease.
Zhou
Jie
J
Department of Biochemistry and Molecular Biology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.
Chen
Juan
J
Feng
Youmei
Y
D000818:Animals; D053327:Apolipoprotein E4 / Q000096:biosynthesis* / Q000235:genetics; D015153:Blotting, Western; D045744:Cell Line, Tumor; D038362:Glycogen Synthase Kinase 3 / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D009447:Neuroblastoma / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D010766:Phosphorylation; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D017384:Sequence Deletion; D014162:Transfection; D016875:tau Proteins / Q000378:metabolism*
D053327:Apolipoprotein E4; D011993:Recombinant Fusion Proteins; D016875:tau Proteins; D049452:Green Fluorescent Proteins; D038362:Glycogen Synthase Kinase 3