School of Chinese Medicine, Hong Kong Baptist University, Kowloon Tong, Hong Kong.
J Alzheimers Dis. 2011;25(2):245-62. doi: 10.3233/JAD-2011-102085.
Cerebral deposition of amyloid-β peptide (Aβ) plaques is now considered the central feature of Alzheimer's disease. Recent studies suggest that cryptotanshinone (CTS) extracted from the root of Salvia miltiorrhiza Bunge could be used for the prevention and treatment of Alzheimer's disease. In this study, we investigated the role of CTS on non-amyloidogenic processing of amyloid-β protein precursor (AβPP) as well as its regulation by protein kinase C (PKC). Treatment with CTS dose-dependently and significantly reduced both intracellular and secreted levels of Aβ40 and Aβ42 in N2a mouse neuroblastoma cells stably expressing human SwedishAβPP (N2a-SwedAβPP). Using N2a-SwedAβPP and human neuroblastoma SHSY5Y cells, it was demonstrated that CTS significantly and dose-dependently increased the production of sAβPPα and C-terminal fragment-α (CTF-α) from AβPP. At the same time, CTS specifically increased the maturation of "a disintegrin and metalloproteinase-10" (ADAM10), an α-secretase candidate. The increase of sAβPPα secretion by CTS was blocked by the hydroxamate-based inhibitors GI254023X and GW280264X, and by the PKC-α inhibitor GÖ6976, suggesting involvement of the ADAM10 and PKC-α in CTS-induced α-secretase cleavage. In other experiments, CTS induced the phosphorylation of PKC-α indicating that PKC-α is involved in CTS-induced sAβPPα secretion. Furthermore, treatment of neuroblastoma cells with CTS induced the co-translocation of ADAM10 and PKC-α to the cell membrane, the site at which AβPP was cleaved, and this translocation was significantly reduced by GÖ6976. These results suggest that CTS-induced sAβPPα secretion is regulated by a PKC-α and ADAM10 cascade in neuroblastoma cells and may be involved in the lowering of Aβ production.
β淀粉样肽（Aβ）斑块在大脑中的沉积现在被认为是阿尔茨海默病的核心特征。最近的研究表明，丹参酮（CTS）从丹参的根中提取可用于预防和治疗阿尔茨海默病。在这项研究中，我们研究了 CTS 对淀粉样β蛋白前体（AβPP）的非淀粉样生成过程的作用及其对蛋白激酶 C（PKC）的调节作用。用 CTS 处理剂量依赖性地显著降低了稳定表达人瑞典 AβPP（N2a-SwedAβPP）的 N2a 小鼠神经母细胞瘤细胞内和分泌的 Aβ40 和 Aβ42 水平。用 N2a-SwedAβPP 和人神经母细胞瘤 SHSY5Y 细胞证明，CTS 显著地和剂量依赖性地增加了 AβPP 的 sAβPPα 和 C 端片段-α（CTF-α）的产生。同时，CTS 特异性地增加了“解整合素和金属蛋白酶-10”（ADAM10），一种α-分泌酶候选物的成熟。CTS 增加 sAβPPα 的分泌被羟肟酸基抑制剂 GI254023X 和 GW280264X 和 PKC-α 抑制剂 GÖ6976 阻断，提示 ADAM10 和 PKC-α 参与了 CTS 诱导的 α-分泌酶裂解。在其他实验中，CTS 诱导了 PKC-α 的磷酸化，表明 PKC-α 参与了 CTS 诱导的 sAβPPα 的分泌。此外，用 CTS 处理神经母细胞瘤细胞诱导 ADAM10 和 PKC-α 向细胞膜的共转位，这是 AβPP 被切割的部位，而 GÖ6976 则显著降低了这种转位。这些结果表明，CTS 诱导的 sAβPPα 的分泌是由神经母细胞瘤细胞中的 PKC-α 和 ADAM10 级联调节的，可能与降低 Aβ 的产生有关。
