富组氨酸糖蛋白HRG在多发性硬化中保护血脑屏障的作用和机制研究

多发性硬化（MS）是一种主要累及中青年、高致残性的中枢神经系统（CNS）自身免疫疾病。血脑屏障（BBB）的破坏是免疫炎性细胞浸润中枢，并促进MS发生发展的关键特征，但是迄今还未找到靶向MS中BBB损伤的临床治疗策略，提示对BBB的研究尚需深入。申请人通过高分辨率液相色谱质谱联用进行高通量蛋白筛选，并与多种中枢疾病对照分析，成功发现富组氨酸糖蛋白HRG特异性在MS病人外周血中显著减少。补充外源HRG后明显减轻MS模型小鼠EAE的BBB损伤及疾病进展。敲除HRG基因后，EAE小鼠疾病及BBB损伤加重。应用新型基于配体的受体捕获技术，申请人发现BBB内皮细胞上GPR124是HRG发挥作用的关键蛋白。基于此，本课题拟应用转基因小鼠、表面等离子体共振、流式等技术，研究：1）HRG改善MS疾病进展的作用；2）HRG作用于BBB内皮细胞，抑制BBB损伤的功能；3）MS中GPR124保护BBB的分子机制。

Multiple sclerosis (MS) is a severe CNS (central nervous system) autoimmune disease characterized with high disability in young populations. Disruption of blood-brain barrier (BBB) is one of the hallmarks of multiple sclerosis (MS), which is closely associated with the progression and outcome of MS. Unfortunately, the targeted therapies on BBB of MS have not been successfully developed in clinic, raising an urgent need to claim the molecular mechanism and key regulator of BBB in MS. My preliminary data show the histidine-rich glycoprotein (HRG) significantly decreased in peripheral blood from MS patients compared to other CNS diseases via high-performance liquid chromatography coupled with tandem mass spectrometry (HPLC–MS) screening. We found the progression of MS in EAE mice model, as well as the damage of BBB were apparently alleviated after supplementation of recombinant HRG. In contrast, the disease severity was aggravated in HRG gene knockout mice. Interestingly, G protein-coupled receptor 124 (GPR124) directly interacted with HRG on endothelial cells of BBB as revealed by ligand-based receptor capture and co-immunoprecipitation. Based on the above preliminary finding, we intends to integrate liquid chromatography-mass spectrometry technique, transgenic mice, surface plasmon resonance (BIAcore) and other state of art technologies for further investigation. We aim to claim: 1) The role of HRG in the development of MS; 2) The impacts and function of HRG endothelial cells of BBB; 3) The molecular mechanism of GPR124 in HRG mediated BBB protection during MS.