Cysteine-Rich Repeat Domains 2 and 4 are Amyloid-β Binding Domains of Neurotrophin Receptor p75NTR and Potential Targets to Block Amyloid-β Neurotoxicity.
Cysteine-Rich Repeat Domains 2 and 4 are Amyloid-β Binding Domains of Neurotrophin Receptor p75NTR and Potential Targets to Block Amyloid-β Neurotoxicity.
复制标题
DOI：
10.3233/jad-171012
复制
发表时间：
2018
期刊：
影响因子：
--
通讯作者：
Ye‐Ran Wang;Jun Wang;Yu-Hui Liu;Gong-Ling Hu;C. Gao;Yanjiang Wang;Xin-Fu Zhou;Fan Zeng
中科院分区：
文献类型：
--
作者：
Ye‐Ran Wang;Jun Wang;Yu-Hui Liu;Gong-Ling Hu;C. Gao;Yanjiang Wang;Xin-Fu Zhou;Fan Zeng
p75神经营养因子受体（p75 NTR）是一种β淀粉样蛋白（amyloid-β，Aβ）受体，它不仅介导Aβ的神经毒性，而且调节Aβ的产生和沉积，在阿尔茨海默病（Alzheimer's disease，AD）的发病机制中发挥重要作用。p75 NTR胞外区（p75 ECD）由4个富含半胱氨酸的重复结构域（CRD）组成，是一种内源性抗A β清除剂，可阻断p75 NTR介导的神经元死亡和轴突变性信号通路。p75 NTR的特异性Aβ结合结构域的鉴定对于阐明它们之间的相互作用和AD的病因学至关重要。通过重组质粒表达或直接合成获得p75 ECD的CRD。应用Aβ聚集抑制试验和免疫沉淀试验对Aβ与p75 ECD的特异性结合域进行定位。采用细胞毒性实验，包括神经突起生长实验、碘化丙啶（propidium iodide，PI）染色和MTT比色法，检测不同CRD对Aβ神经毒性的拮抗作用。在Aβ聚集抑制试验中，CRD 2和CRD 4处理组的荧光强度显著低于CRD 1和CRD 3处理组。免疫沉淀和western blot证实Aβ可与CRD 2和CRD 4结合。CRD 2和CRD 4可拮抗Aβ神经毒性，表现为较对照组神经突起长，PI标记细胞数少，细胞活力高。我们的研究结果表明CRD 2和CRD 4是p75 NTR的Aβ结合结构域，能够拮抗Aβ的神经毒性，因此是阻断Aβ和p75 NTR相互作用的潜在治疗靶点。
The p75 neurotrophin receptor (p75NTR) is an amyloid-β (Aβ) receptor that both mediates Aβ neurotoxicity and regulates Aβ production and deposition, thus playing an important role in the pathogenesis of Alzheimer's disease (AD). The extracellular domain of p75NTR (p75ECD), consisting of four cysteine-rich repeat domains (CRDs), was recently reported to be an endogenous anti-Aβ scavenger to block p75NTR-mediated neuronal death and neurite degeneration signaling of Aβ and pro-neurotrophins. Identification of the specific Aβ binding domains of p75NTR is crucial for illuminating their interactions and the etiology of AD. CRDs of p75ECD were obtained by expression of recombinant plasmids or direct synthesis. Aβ aggregation inhibiting test and immunoprecipitation assay were applied to locate the specific binding domains of Aβ to p75ECD. The Aβ neurotoxicity antagonistic effects of different CRDs were examined by cytotoxicity experiments including neurite outgrowth assay, propidium iodide (PI) staining, and MTT assay. In the Aβ aggregation inhibiting test, the fluorescence intensity in the CRD2 and CRD4 treatment groups was significantly lower than that in the CRD1 and CRD3 treatment groups. Immunoprecipitation assay and western blot confirmed that Aβ could bind to CRD2 and CRD4. Besides, CRD2 and CRD4 antagonized Aβ neurotoxicity suggested by longer neurite length, less PI labelled cells, and higher cell viability than the control group. Our results indicate that CRD2 and CRD4 are Aβ binding domains of p75NTR and capable of antagonizing Aβ neurotoxicity, and therefore are potential therapeutic targets to block the interaction of Aβ and p75NTR in the pathogenesis of AD.