Open AccessDehydroevodiamine attenuates calyculin A‐induced tau hyperphos‐phorylation in rat brain slices 1
Author(s) -
FANG Jiang,
LIU Rong,
TIAN Qing,
HONG Xiaoping,
WANG Shaohui,
CAO Fuyuan,
PAN Xiping,
WANG Jianzhi
Publication year - 2007
Publication title -
acta pharmacologica sinica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.514
H-Index - 90
eISSN - 1745-7254
pISSN - 1671-4083
DOI - 10.1111/j.1745-7254.2007.00655.x
Subject(s) - hyperphosphorylation , phosphorylation , phosphatase , tau protein , chemistry , medicine , blot , microbiology and biotechnology , biology , endocrinology , biochemistry , alzheimer's disease , disease , gene
Aim: This study was to investigate the effect of dehydroevodiamine (DHED) on Alzheimer's disease (AD)‐like tau hyperphosphorylation induced by calyculin A (CA), an inhibitor of protein phosphatase (PP)‐2A and PP‐1, and the involvement of PP‐2A in metabolically competent rat brain slices. Methods: Rat brain slices were pre‐incubated at 33°C in the presence (10, 100, and 200 μmol/L, respectively) or absence of DHED for 1 h. Then, CA 0.1 μmol/L was added and the slices were treated for another 2 h. Western blotting and/or immunohistochemistry were used to measure the phosphorylation level of tau and PP‐2A. Results: CA treatment could remarkably increase the immunoreactivity of pS262 and decrease the staining of Tau‐1, representing tau hyperphosphorylation at Ser262 (pS262) and Ser198/ 199/202 (Tau‐1, as the antibody reacts with unphosphorylated tau, therefore, decreased staining represents increased phosphorylation). Pre‐incubation of the brain slices with DHED could efficiently attenuate the CA‐induced tau hyperphosphorylation at the above AD‐related sites. Additionally, DHED also decreased the basal phosphorylation level of tau at Ser396, although CA failed to induce tau hyperphosphorylation at this site. Furthermore, CA treatment induced an increased level of Tyr307‐phosphorylated PP‐2A, which represents inactivation of the phosphatase, whereas DHED arrested the elevation of the inhibitory modification of PP‐2A. Conclusion: DHED can attenuate CA‐induced tau hyperphosphorylation at multiple AD‐related sites in metabolically active rat brain slices. The underlying mechanism may involve a decreased inhibitory phosphorylation of PP‐2A at Tyr307.