Agrin在间充质干细胞调控水通道蛋白-4极性分布改善中年HD小鼠脑类淋巴功能中的机制研究

反义寡核苷酸（ASO）是目前唯一通过临床II期研究的亨廷顿病基因疗法。然而，鞘内注射ASO的疗效不足脑组织直接给药疗效的50%。我们发现，这可能是由于鞘内注射的ASO主要通过脑类淋巴系统入脑，但HD小鼠的脑类淋巴功能受损，使得ASO的入脑效率明显下降。我们前期发现，AQP-4定位异常是导致中年HD小鼠脑类淋巴功能紊乱的原因，而间充质干细胞（MSC）可纠正其AQP-4的定位异常并改善脑类淋巴功能，提高ASO的疗效，但其机制不清。研究表明，Agrin是介导AQP-4正常定位的关键蛋白，而我们发现MSC可以促进其分泌，这提示Agrin可能是MSC改善中年HD小鼠脑类淋巴功能的作用靶点。因此，本课题将以Agrin为切入点，从功能、结构及蛋白互作层面探索MSC改善中年HD小鼠脑类淋巴功能的分子机制，为更好地对MSC进行基因编辑，从而使其发挥更强的脑类淋巴功能调控作用，提供理论依据。

Antisense Oligonucleotide (ASO) is currently the only gene therapy for Huntington's disease that has passed clinical phase II studies. However, the efficacy of intrathecal injection of ASO is less than 50% to that of direct administration into brain. We found that this may be due to the fact that the intrathecal ASO mainly enters the brain through the glymphatic system, but the glymphatic function of HD mice is impaired, which makes the efficacy of ASO significantly decreased. We previously found that abnormal AQP-4 localization is the cause of glymphatic dysfunction in middle-aged HD mice, and mesenchymal stem cells (MSC) can correct the abnormal localization of AQP-4 and improve glymphatic function and increase the ASO efficacy, but its mechanism is unclear. Studies have shown that Agrin is a key protein that mediates the polarity of AQP-4, and we found that MSC can promote its secretion, which suggests that Agrin may be a target for MSC to improve glymphatic function in middle-aged HD mice. Therefore, this study will use Agrin as the entry point to explore the mechanism of MSC improving glymphatic function in middle-aged HD mice from the level of function, structure and protein interaction. It will provide a theoretical basis to further optimize MSC, so as to better promote the glymphatic function of HD. It will at last improve the efficacy of intrathecal injection of drugs such as ASO.