论文部分内容阅读
Aim:This study was to investigate the effect of dehydroevodiamine (DHED) onAlzheimer’s disease (AD)-like tau hyperphosphorylation induced by calyculin A(CA),an inhibitor of protein phosphatase (PP)-2A and PP-1,and the involvementof PP-2A in metabolically competent rat brain slices.Methods:Rat brain sliceswere pre-incubated at 33℃ 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 weretreated for another 2 h.Western blotting and/or immunohistochemistry were usedto measure the phosphorylation level of tau and PP-2A.Results:CA treatmentcould remarkably increase the immunoreactivity of pS262 and decrease the stain-ing of Tau-1,representing tau hyperphosphorylation at Ser262 (pS262) and Ser198/199/202 (Tau-1,as the antibody reacts with unphosphorylated tau,therefore,de-creased staining represents increased phosphorylation).Pre-incubation of thebrain slices with DHED could efficiently attenuate the CA-induced tau hyperphos-phorylation at the above AD-related sites.Additionally,DHED also decreased thebasal phosphorylation level of tau at Ser396,although CA failed to induce tauhyperphosphorylation at this site.Furthermore,CA treatment induced an increasedlevel of Tyr307-phosphorylated PP-2A,which represents inactivation of thephosphatase,whereas DHED arrested the elevation of the inhibitory modificationof PP-2A.Conclusion:DHED can attenuate CA-induced tau hyperphosphorylationat multiple AD-related sites in metabolically active rat brain slices.The underlyingmechanism may involve a decreased inhibitory phosphorylation of PP-2A atTyr307.
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 sliceswere pre-incubated at 33 ° C in the presence (10,100, and 200 μmol / L, respectively) or absence of DHED for 1 h. 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 can remarkably increase the immunoreactivity of pS262 and decrease the stain-of Tau-1, presenting tau hyperphosphorylation at Ser262 (pS262) and Ser198 / 199/202 (Tau-1, as the antibody reacts with unphosphorylated tau, therefore, de- creased staining for increased phosphorylation) .Pre-incubation of thebrain slices with DHED could efficiently attenuate the CA-induced tau hyp erphos-phorylation at the above AD-related sites. Additionally, DHED also decreased the basal phosphorylation level of tau at Ser396, although CA failed to induce tauhyperphosphorylation at this site. Morerther, CA treatment induced an increased level of Tyr307-phosphorylated PP-2A, which represents inactivation of the phosphatase, while DHED arrested the elevation of the inhibitory modification of PP-2A. Conlusion: DHED can attenuate CA-induced tau hyperphosphorylation of multiple AD-related sites in metabolically active rat brain slices. The underlying mechanism may involve a decreased inhibitory phosphorylation of PP -2A atTyr307.