SH-SY5Y细胞α7尼古丁受体蛋白抑制对tau蛋白及p38 MAPK通路的影响及其与AD发病机制的关系

Influence of inhibited α7 nicotinic acetylcholine receptor protein expression on tau protein and p38 MAPK signal transduction pathway in SH-SY5Y cells and the relationship with the pathogenesis of AD

目的研究α7尼古丁受体(nAChR)蛋白抑制对SH-SY5Y细胞tau蛋白磷酸化水平的影响及其与p38 MAPK通路的关系,探讨α7 nAChR调节tau蛋白磷酸化的相关机制。方法用α7 nAChR阻断剂MLA阻断SH-SY5Y细胞α7 nAChR蛋白的活化及其表达,用p38 MAPK阻断剂SB203580阻断SH-SY5Y细胞p38 MAPK信号通路蛋白的活化及其表达,Western blotting方法测定tau蛋白、p-tau(S404)、p-tau(S214)、α7 nAChR、p38 MAPK及p-p38 MAPK(Thr180/Tyr182)蛋白表达水平。结果细胞经MLA处理后,p-tau(S404)和p-tau(S214)蛋白水平明显升高(P<0.01),p-p38 MAPK和α7 nAChR蛋白水平明显降低(P<0.01),tau蛋白和p38 MAPK蛋白水平保持不变;经SB203580处理后,SB203580及MLA共同处理后均引起p-tau(S404)、p-tau(S214)、p-p38 MAPK和α7nAChR蛋白水平显著降低(P<0.01),tau蛋白和p38 MAPK蛋白水平无变化。结论α7 nAChR可通过阻断p38MAPK信号传导通路抑制tau蛋白过度磷酸化。

Objective To investigate the influence of inhibited protein expression of α7 neuronal nicotinic acetyl-choline receptor （nAChR） on tau phosphorylation and the relationship with p38 MAPK signal transduction pathway in SH- SY5Y cells,to study the effected mechanism of al nAChR on tau phosphorylation. Methods SH-SY5Y cells were exposed to MLA and SB203580,respectively,to block the activation and protein expression of α7 nAChR and p38 MAPK pathway. The protein levels of tau,p-tau （S404） ,p-tau （S214） ,a7 nAChR,p38 MAPK and p-p38 MAPK （Thrl80/Tyrl82） were measured by Western blotting. Results As compared with negative controls,in MLA treated group,the expressions of p-tau （S404） and p-tau （S214） were increased and the protein levels of α7 nAChR and p-p38 MAPK were decreased signifi-cantly, tau and p38 MAPK protein expressions were unchanged. In SB203580 treated group and both two medicines treated group, the expressions of p-tau （S404）, p-tau （S214）,a7 nAChR and p-p38 MAPK were both decreased conspicuously, the protein levels of tau and p38 MAPK were still unchanged. Conclusions Blocked p38 MAPK signal transduction pathway can prevent against the al nAChR-induced tau hyperphosphorylation.