重组人tau蛋白对神经细胞的毒性作用

Toxic effect of recombinant human tau on neural cells

目的观察重组人tau蛋白对神经来源的细胞株SH-SY5Y及体外原代培养的神经元是否有毒性作用。方法将原核表达纯化的重组人tau蛋白加入SH-SY5Y细胞和原代培养的大鼠神经元培养液中,通过观察细胞形态、四甲基偶氮唑盐(MTT)检测细胞增殖活性、TUNEL染色检测细胞凋亡、免疫荧光染色观察凋亡诱导蛋白CHOP及内质网应激上调蛋白ARMET的表达情况研究tau蛋白对神经细胞生长、增殖和凋亡的影响。结果随着tau蛋白作用时间的延长,细胞胞体逐渐变圆,突起减少甚至消失,染色质聚集,部分神经元出现了凋亡。MTT检测结果显示tau蛋白可抑制细胞的增殖。同时发现,细胞外的tau作用可诱导内质网应激标志性蛋白CHOP和ARMET的表达。结论重组人tau蛋白对神经细胞有毒性作用,该作用可能部分与tau诱导的内质网应激有关。

Objective To investigate whether recombinant human tau protein is toxic to both primary cultured neutons and SH-SYSY cells. Methods Primary cultured neurons and SH-SYSY cells were treated with the purified tau protein expressed in prokaryotic cells. The viability of ceils was determined by MTT assay, and the apoptotic cells were determined by TUNEL and DAPI staining. The expressions of CHOP and ARMET induced by tau were measured by immunofluorescent staining. Results After treatment with tau protein, both primary cultured neurons and SH-SYSY cells became round and axons gradually disappeared. We also observed that tau protein induced the typically apoptotic characteristics, including nuclei getting smaller and chromatin getting condensed. Moreover, tau protein inhibited cell proliferation. The further study found that tau increased CHOP and ARMET expression, which were up-regulated by endoplasmic reticulum （ER） stress. Conclusion The recombinant human tau protein induces neural cell apoptosis via at least in part triggering ER stress.