利用PMCA技术实验不同剂量MCT联合DTT对PrP^(sc)转化的抑制效应

The Inhibitory Effect of MCT in Different Concentration with DTT on Amplification of PrP^(sc) by PMCA in vitro

蛋白质错误折叠循环扩增(protein misfolding cyclic amplification,PMCA)技术,是一种具有感染性的朊蛋白(PrPsc)体外扩增的技术,可用于抑制细胞型朊蛋白(PrPc)向PrPsc转化药物的筛选.本研究在Saborio等提供的方法基础上,成功优化了最佳扩增时间,利用优化的PMCA技术实验了不同剂量氮芥(mechlorethamine,MCT)联合二硫苏糖醇(dithiothreitol,DTT)对PrPsc转化的抑制效应.结果发现,MCT联合DTT能体外抑制PrPc向PrPsc的转化,抑制作用具有明显的量效关系.利用针对人PrPc不同结构域的抗体发现,MCT联用DTT可使抗体6H4的抗原表位隐蔽,该表位位于PrPc第1个α螺旋区内,是构象转化的主要部位.对其机制的深入探讨,将有助于新一类可传播性海绵状脑病(transmissible spongiform encephalopathy,TSE)治疗药物的研发.

Protein misfolding cyclic amplification（PMCA） technology simulates the amplification of scrapie prion protein（PrPsc） in vitro and be used for the screening of the drug which inhibits the conversion of cellular prion protein（PrPc） to PrPsc.In this study,the PMCA was successfully established according to the method reported by Saborio et al and further optimized.By the optimal PMCA technology,it was found that mechlorethamine（MCT） and dithiothreitol（DTT） inhibited the conversion of PrPc to PrPsc in vitro and showed a significant dose-dependent effect.By antibodies binding with different domains of PrPc,it was found that epitope of antibody 6H4 was concealed after treatment by MCT with DTT.The epitope of antibody 6H4 is in the first helix domain of PrPc,where the conformation conversion from PrPc to PrPsc takes place.Further research on the mechanism will benefit the development for new drug for transmissible spongiform encephalopathy（TSE）.