MG132对SH-SY5Y细胞Aβ水平的影响

目的:观察蛋白酶体抑制剂MG132诱导SH-SY5Y细胞凋亡及调节β-淀粉样蛋白(beta-amyloid protein,Aβ)生成的作用,并对其机制进行探讨。方法:培养SH-SY5Y细胞,MG132对细胞进行处理,浓度分别为2.5μmol/L、5μmol/L和10μmol/L,24 h后检测各项指标。MTT法检测细胞活力;流式细胞术检测细胞凋亡;ELISA法检测细胞Aβ_(1-40)和Aβ_(1-42)水平;Western blot检测淀粉样蛋白前体蛋白(amyloid precursor protein,APP)、β-分泌酶(BACE1)、早老蛋白1(presenilins 1,PS1)、早老蛋白2(presenilins 2,PS2)、nicastrin(NCT)和α-分泌酶(ADAM10)蛋白表达。结果:经MG132处理后,细胞活力明显下降,诱导细胞凋亡,随剂量增加凋亡率分别为36.97%、46.20%、50.50%;细胞Aβ_(1-42)和Aβ_(1-40)蛋白水平明显上升;APP及Aβ代谢相关蛋白PS1、PS2和BACE1表达均出现剂量依赖性的增加,而ADAM10表达呈剂量依赖性降低;NCT水平变化不明显。结论:MG132能诱导神经细胞凋亡,通过影响Aβ生成途径关键蛋白而促进Aβ的产生,说明蛋白酶体活性下降可通过调节Aβ途径参与阿尔茨海默病的发生。

Effect of MG132 on Aβ generation in SH-SY5Y cells

AIM: To observe the influences of different concentrations of MG132 on apoptosis and beta-amyloid protein(Aβ) generation in SH-SY5Y cells, and to explore the underlying mechanism.METHODS: SHSY-5Y cells were incubated with MG132 for 24 h. The final concentrations of MG132 were 2.5, 5 and 10 μmol/L. The cell viability was determined by MTT assay. The cell apoptosis was assessed by flow cytometry. The levels of Aβ were measured by ELISA. The relative protein levels were detected by Western blot.RESULTS: In the SH-SY5Y cells, MG132 reduced the cell viability, induced the cell apoptosis, increased the level of Aβ, and increased the expression of the related proteins for Aβ generation in a concentration-dependent manner.CONCLUSION: MG132 induces apoptosis and increases the levels of Aβ_1-42 and Aβ_1-40 by regulating the proteins related to Aβ generation in the SH-SY5Y cells.