中药野拔子基于α7 nAChR/RAGE调控促进AD神经血管单元修复的机制研究

Alzheimer's disease (AD) is a progressive neurodegenerative disorder with multiple pathological mechanisms which are fallen within the neurovascular unit (NVU) pathological changes. Up to now, there are no effective drugs in the treatment of this disease. Under the support of previous project of National Natural Science Foundation of China, we found that several potential molecules form the pathological network involved in the mechanisms of injury of the NVU, such as α7 nAChR and RAGE. We also have evidenced that α7 nAChR specifically interferes RAGE expression and its signal transduction and alleviates NVU inflammation through CaMK, CREB, and AKT pathways. Recently, we found that several natural active compounds isolated from Elsholtzia Rugulosa (Labiatae) showed the effects on the prevention and treatment of AD. These compounds can specifically activate α7nAChR, and can inhibit RAGE expression as well. They exhibit the ability to protect the NVU through multiple pathways. But the role and mechanism that they act with α7 nAChR/RAGE regulation in the NVU still need to be investigated. This project aims to investigate and verify whether α7 nAChR acts as a RAGE-regulation protein, explore the disease-networks in the NVU possibly formed by α7 nAChR by using NVU as a local unit of the brain, and discover the mechanisms of natural active compounds isolated from Elsholtzia Rugulosa (Labiatae) in the treatment of AD through targeting α7 nAChR and RAGE molecules. This project will use the knockout and functional pathway protein chip technologies. And finally, we will illustrate the key molecular mechanisms of α7 nAChR in AD both in pathological signal network and the mechanisms of drug effects by α7 nAChR/RAGE regulation in the NVU. Thus, we will offer a theoretical basis to investigate the pathological role of α7 nAChR, and also provide an effective method for drug discovery of AD.

阿尔茨海默病（AD）发病机制复杂，缺乏有效防治药物。本课题前期证明α7nAChR、RAGE等形成AD神经血管单元(NVU)病理网络，α7nAChR经CaMK、MAPK、AKT特异干扰RAGE通路，缓解NVU损伤。近期又发现，中药野拔子活性单体可防治AD，既能选择性激动α7nAChR，又能适度抑制RAGE，有多途径的NVU保护作用，但其促进NVU修复的机制仍需深入研究。 本课题以α7nAChR作为RAGE调节蛋白进行确证研究，以NVU修复作为功能单位，对α7nAChR等分子的网点式通路进行探索研究，对野拔子单体开展抗AD机制研究，借助基因敲除、功能通路芯片等技术，在基因调控、信号转导等方面，探讨α7nAChR调节RAGE的关联通路及在NVU的有效调控网络，阐释野拔子基于α7nAChR/RAGE调控促进NVU修复的机制。为研究α7nAChR病理作用提供理论依据，为开发防治AD新药提供有效方法。

阿尔茨海默病（Alzheimer’s disease，AD）是发生于老年或老年前期的慢性进行性神经退行性病变，传统的基于单一靶标或单一信号通路的药物发现策略对于机制复杂、病因不明的AD而言，一直没有找到理想的防治药物，因而寻找多靶标联合作用的药物，很可能为防治该病提供有效手段。本项目以脑组织神经血管单元（NVU）功能调节作为局部整体单位，基于α7 nAChR、RAGE等NVU关键调节蛋白所形成的病理分子网络，对中药野拔子中的活性单体开展防治AD的机制研究，阐释野拔子基于α7 nAChR/RAGE等信号通路促进NVU修复的作用机制。.本项目通过建立APP/PS1 α7 nAChR（-/-）、APP/PS1 RAGE（-/-）等模式动物模型及构建野生型、阻断型α7 nAChR/RAGE等细胞株，明确了α7 nAChR、RAGE的相互作用方式及相关信号通路，提出其促进脑组织神经血管单元局部整体修复的分子机制，建立了基于α7 nAChR-RAGE-p38 MAPK-JNK-NF-κB关键分子防治AD的药物靶标网络。并从整体水平、细胞水平、分子水平，阐明中药野拔子三种有效活性成分基于α7 nAChR/RAGE调控作用的作用机理，证实其具有低毒、有效的RAGE表达抑制作用、α7 nAChR激活作用及NVU保护作用，以及对AD具有防治作用，通过特异性作用于α7 nAChR/RAGE介导的信号通路保护神经细胞免受Aβ损伤，维持NVU超微结构完整性，改善微血管内皮细胞功能，提高胆碱能神经功能，纠正细胞内α7 nAChR-RAGE-p38 MAPK-JNK-NF-κB等关键分子形成的病理性信号通路。综上所述，本项目明确了α7 nAChR、RAGE及其信号通路的直接调节作用和间接调节作用途径，阐释了野拔子活性物质基于α7 nAChR/RAGE关键靶标的抗AD分子机理，为以RAGE和α7 nAChR为作用靶标、以NVU局部功能调节为靶向的药物研究提供了理论基础和实验依据。