蛋白酶体抑制剂ALLN促进α-synuclein转染SH-SY5Y细胞内包涵体形成

Proteasome inhibitor ALLN promotes inclusion formation in α-synuclein transfected SH-SY5Y cells

目的研究蛋白酶体功能障碍在帕金森病发病机制中的作用。方法采用蛋白酶体抑制剂ALLN(N-acetyl-Leu-Leu-Norleucinal)处理-αsynuclein转染的体外培养SH-SY5Y细胞。HE染色和免疫荧光细胞化学检测转基因表达产物在细胞内的积聚,TUNEL法检测细胞凋亡情况。结果-αsynuclein可在细胞内自发蓄积形成包涵体,ALLN可明显促进包涵体形成;该包涵体呈-αsynuclein免疫反应阳性而泛素免疫反应阴性;含有包涵体的细胞可同时表现为TUNEL反应阳性。结论蛋白酶体功能障碍可能在帕金森病发病过程中发挥重要作用。

Abstract： Objective To investigate whether the proteasome dysfunction and α-synuclein overexpression is in volved inthe genesis of neuronal degeneration in Parkinson＇s disease （ PD）. Methods The pharmacological inhibitor of the proteasome, ALLN, was used to model proteasomal dysfunction in cultured dopaminergic SH-SY5Y cell lines expressing α-synuclein, the characteristic protein accumulated in Lewy bodies. The expression of α-synuclein was determined by anti-α-synuclein immunocytochemistry. The aggregates in the cultured cells were identified with HE staining and anti-α-synuclein immunocytochemistry. The cellular apoptosis was determined with TUNEL staining. Results The proteasome inhibitor, ALLN, induced α-synuclein protein aggregate and lead to the formation of eosinophilic intracytoplasmic inclusions,which was immunoreactive to α-synuclein but not to ubiquitin. Some inclusion-harboring cells revealed positive TUNEL staining. Conclusion The proteasome plays an important role in the metabolism of α-synuclein, inclusions formation and dopaminergic neuronal death.