Department of Demyelinating Disease and Aging, National Institute of Neuroscience, NCNP, 4-1-1 Ogawahigashi, Kodaira, Tokyo, 187-8502, Japan.
Neurochem Res. 2013 Mar;38(3):589-600. doi: 10.1007/s11064-012-0956-1. Epub 2012 Dec 28.
Statins, 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors, have been reported to attenuate amyloid-β peptide (Aβ) production in various cellular models. However, the mechanisms by which statins affect neuronal Aβ production have not yet been clarified. Here, we investigated this issue in rat primary cortical neurons using two statins, pitavastatin (PV) and atorvastatin (AV). Treatment of neurons with 0.2-2.5 μM PV or AV for 4 days induced a concentration- and time-dependent reduction in the secretion of both Aβ40 and Aβ42. Moreover, Western blot analyses of cell lysates showed that treatment with PV or AV significantly reduced expression levels of the mature form of amyloid precursor protein (APP) and Thr668-phosphorylated APP (P-APP), but not immature form of APP; the decreases in P-APP levels were more notable than those of mature APP levels. The statin treatment did not alter expression of BACE1 (β-site APP-cleaving enzyme 1) or γ-secretase complex proteins (presenilin 1, nicastrin, APH-1, and PEN-2). In neurons overexpressing APP via recombinant adenoviruses, PV or AV similarly reduced Aβ secretion and the levels of mature APP and P-APP. Statins also markedly reduced cellular cholesterol content in neurons in a concentration-dependent manner. Co-treatment with mevalonate reversed the statin-induced decreases in Aβ secretion and mature APP and P-APP levels, whereas co-treatment with cholesterol did not, despite recovery of cellular cholesterol levels. Finally, cell-surface biotinylation experiments revealed that both statins significantly reduced the levels of cell-surface P-APP without changing those of cell surface mature APP. These results suggest that statins reduce Aβ production by selectively modulating APP maturation and phosphorylation through a mechanism independent of cholesterol reduction in cultured neurons.
他汀类药物，即 3-羟基-3-甲基戊二酰辅酶 A（HMG-CoA）还原酶抑制剂，已被报道可减少各种细胞模型中的淀粉样β肽（Aβ）产生。然而，他汀类药物影响神经元 Aβ产生的机制尚未阐明。在这里，我们使用两种他汀类药物匹伐他汀（PV）和阿托伐他汀（AV）在大鼠原代皮质神经元中研究了这个问题。用 0.2-2.5μM 的 PV 或 AV 处理神经元 4 天，可浓度和时间依赖性地减少 Aβ40 和 Aβ42 的分泌。此外，细胞裂解物的 Western blot 分析表明，PV 或 AV 处理可显著降低成熟形式的淀粉样前体蛋白（APP）和 Thr668 磷酸化的 APP（P-APP）的表达水平，但不影响不成熟形式的 APP；P-APP 水平的降低比成熟 APP 水平的降低更为显著。他汀类药物处理不会改变 BACE1（β-位点 APP 切割酶 1）或 γ-分泌酶复合物蛋白（早老素 1、尼卡斯特林、APH-1 和 PEN-2）的表达。在通过重组腺病毒过表达 APP 的神经元中，PV 或 AV 同样减少了 Aβ 的分泌以及成熟 APP 和 P-APP 的水平。他汀类药物也可浓度依赖性地显著降低神经元中的细胞胆固醇含量。甲羟戊酸共处理逆转了他汀类药物诱导的 Aβ 分泌以及成熟 APP 和 P-APP 水平的降低，而胆固醇共处理则没有，尽管恢复了细胞胆固醇水平。最后，细胞表面生物素化实验表明，两种他汀类药物都显著降低了细胞表面 P-APP 的水平，而不改变细胞表面成熟 APP 的水平。这些结果表明，他汀类药物通过一种独立于胆固醇降低的机制，选择性地调节 APP 成熟和磷酸化，从而减少培养神经元中的 Aβ 产生。
