Medical Research Center for Ischemic Tissue Regeneration, Pusan National University, Yangsan-si, Gyeongsangnam-do, Republic of Korea.
J Neurosci Res. 2014 Feb;92(2):206-17. doi: 10.1002/jnr.23310. Epub 2013 Nov 19.
β-Amyloid (Aβ) deposits and hyperphosphorylated tau aggregates are the chief hallmarks in the Alzheimer's disease (AD) brains, but the strategies for controlling these pathological events remain elusive. We hypothesized that CK2-coupled SIRT1 activation stimulated by cilostazol suppresses tau acetylation (Ac-tau) and tau phosphorylation (P-tau) by inhibiting activation of P300 and GSK3β. Aβ was endogenously overproduced in N2a cells expressing human APP Swedish mutation (N2aSwe) by exposure to medium containing 1% fetal bovine serum for 24 hr. Increased Aβ accumulation was accompanied by increased Ac-tau and P-tau levels. Concomitantly, these cells showed increased P300 and GSK3β P-Tyr216 expression; their expressions were significantly reduced by treatment with cilostazol (3-30 μM) and resveratrol (20 μM). Moreover, decreased expression of SIRT1 and its activity by Aβ were significantly reversed by cilostazol as by resveratrol. In addition, cilostazol strongly stimulated CK2α phosphorylation and its activity, and then stimulated SIRT1 phosphorylation. These effects were confirmed by using the pharmacological inhibitors KT5720 (1 μM, PKA inhibitor), TBCA (20 μM, inhibitor of CK2), and sirtinol (20 μM, SIRT1 inhibitor) as well as by SIRT1 gene silencing and overexpression techniques. In conclusion, increased cAMP-dependent protein kinase-linked CK2/SIRT1 expression by cilostazol can be a therapeutic strategy to suppress the tau-related neurodegeneration in the AD brain.
β-淀粉样蛋白（Aβ）沉积和过度磷酸化的 tau 聚集体是阿尔茨海默病（AD）大脑中的主要标志物，但控制这些病理事件的策略仍然难以捉摸。我们假设，西洛他唑刺激的 CK2 偶联 SIRT1 激活通过抑制 P300 和 GSK3β 的激活来抑制 tau 乙酰化（Ac-tau）和 tau 磷酸化（P-tau）。通过将 N2a 细胞暴露于含有 1%胎牛血清的培养基中 24 小时，在表达人 APP 瑞典突变（N2aSwe）的 N2a 细胞中内源产生过多的 Aβ。Aβ 积累增加伴随着 Ac-tau 和 P-tau 水平的增加。同时，这些细胞显示出 P300 和 GSK3β P-Tyr216 表达增加；它们的表达通过西洛他唑（3-30 μM）和白藜芦醇（20 μM）处理明显降低。此外，Aβ 对 SIRT1 的表达及其活性的降低被西洛他唑和白藜芦醇显著逆转。此外，西洛他唑强烈刺激 CK2α 磷酸化及其活性，然后刺激 SIRT1 磷酸化。这些作用通过使用药理学抑制剂 KT5720（1 μM，PKA 抑制剂）、TBCA（20 μM，CK2 抑制剂）和 sirtinol（20 μM，SIRT1 抑制剂）以及 SIRT1 基因沉默和过表达技术得到证实。总之，西洛他唑增加 cAMP 依赖性蛋白激酶连接的 CK2/SIRT1 表达可以成为抑制 AD 大脑中 tau 相关神经退行性变的治疗策略。
