岩藻糖基化海参硫酸软骨素促进神经干细胞向脑损伤部位迁移的作用及其机制研究

Present an ideal strategy to promote the repair of brain damage from exogenous stem cells is an effective complement to tissue remodeling and repair functions play in the injury site. Migration of neural stem cells (NSCs) transplantation therapy requires accurate control of NSCs, or the treatment effect will be greatly affected. Our pre-separation of the stichopus japonicus polysaccharide(SJP),a kind of sea cucumber chondroitin sulfate, can effectively promote NSCs migration, and significantly enhance the chemokine-induced NSCs migration activity. Chemokine is considered to be the main stem cell homing factors that enhance the activity of chemokines NSCs tend to migrate to the injury site. This project through the establishment of rat model of cerebral ischemia, in vitro studies SJP, chemokines, and NSCs induced by the interaction characteristics and SJP mechanism of NSCs to migrate. To GFP and magnetic labeled NSCs United SJP intra-arterial injection of brain injury in rats, and recently using MRI of cells in vivo tracking, long-term pathological tracer method combined with immune cells staining, HE staining, histological analysis of NSCs in the damaged brain tissue localization, proliferation activity, the differentiation outcome. Further new strategy for the full mobilization of NSCs to promote the repair of brain damage by enhancing the ability of chemokine activity in the detection of NSCs in the injured tissues tend to migrate.

当前促进大脑损伤修复的理想策略是使外源性神经干细胞(NSCs)有效补充于损伤部位并发挥组织重构和修复功能。NSCs移植疗法面临的难题之一是有效调控NSCs向损伤部位的迁移。我们在前一国家基金项目研究中获得的岩藻糖基化海参硫酸软骨素(简称刺参多糖,SJP)能有效促进NSCs迁移,且显著增强趋化因子诱导NSCs迁移的活性。趋化因子是主要的干细胞归巢因子。研究认为增强趋化因子的活性有助于NSCs向损伤部位迁移。本项目在前期工作基础上,先在体外研究SJP、趋化因子和NSCs之间的相互作用及SJP诱导NSCs迁移的作用机制。再通过建立大鼠脑缺血模型,将标记的NSCs联合SJP经动脉注入脑损伤大鼠,研究SJP促进NSCs向脑损伤部位迁移的作用及疗效。本项目的研究将为解决NSCs用于修复脑损伤面临的有效迁移等问题提供解决方案和理论、技术上的实验证据,为充分动员NSCs促进脑损伤修复提供新思路、新策略。

当前促进大脑损伤修复的理想策略是使外源性神经干细胞有效补充于损伤部位并发挥其组织重构和修复功能。目前神经干细胞（NSCs）移植疗法面临的难题之一是有效调控NSCs向损伤部位的迁移。本项目前期研究表明：岩藻糖基化海参硫酸软骨素（简称刺参多糖，SJP）能有效促进NSCs迁移，且能显著增强趋化因子诱导NSCs迁移的活性。在此基础上本项目首先在体外研究了SJP、岩藻聚糖硫酸酯或肝素与趋化因子对NSCs迁移的影响，然后深入研究了SJP通过增强SDF-1α/CXCR4轴促进NSC向病灶区域迁移的具体信号通路。研究结果表明：SJP、岩藻聚糖硫酸酯或肝素与SDF-1/CXCR4 轴相互作用促进神经干细胞的迁移。其中SJP主要通过对SDF-1α/CXCR4轴的增强作用调节NSC的迁移，其信号通路为PI3K/Akt/FOXO3a，ERK/MAPK和NF-κB信号通路。. 为了扩大SJP在神经退行性疾病治疗中的应用范围，本项目还研究了SJP对PC12细胞缺氧复氧（H/R）损伤和6-OHDA诱导的神经细胞帕金森症损伤的保护作用及其作用机制。研究结果表明：SJP通过p38和JNKMAPK信号通路对PC12细胞H/R损伤起保护作用，并可通过抑制p38 MAPK和JNK通路的激活和PI3K/Akt通路的失活对6-OHDA诱导的神经细胞损伤起保护作用。. 另外本项目对SJP类似物岩藻聚糖硫酸酯进行了荧光标记，并以FITC-岩藻聚糖硫酸酯为原料，通过细胞和动物实验证明FITC-岩藻聚糖硫酸酯可以被肠道吸收，且在细胞层面的吸收作用大于外排作用，其吸收机制可能为依赖于网格蛋白的胞吞作用。药代动力学实验表明岩藻聚糖硫酸酯能够进入血液循环，其口服生物利用度为2.67%。. 综上，本项目的研究表明SJP不仅有通过PI3K/Akt/FOXO3a，ERK/MAPK和NF-κB信号通路促进神经干细胞迁移的活性，还对神经退行性疾病的神经细胞损伤有保护作用。本项目的研究为SJP作为一种潜在药物在治疗神经退行性疾病中的应用提供了实验依据。