不同阳离子构成的LDH调控神经干细胞促脊髓损伤修复作用及机制研究

Spinal cord injury (SCI) has been among the most important unsolved problems in medicine. The deteriorating microenvironment of injury site causes neuron death and prevents neural stem cell（NSCs）from differentiating to neuron, thus improving the microenvironment of SCI site and promoting commitment differentiation of NSCs have become the key problem of SCI repair. Layered double hydroxide (LDH) nanoparticles have great potential for application in SCI repair, which have a lot of advantages such as good biocompatibility, inflammation suppression and can help embryonic stem cell keeping pluripotent. This project plans to synthesize LDHs with different metal cations, measure the physical and chemical characterizations, then evaluate their effect on migration, proliferation and differentiation of NSCs, as well as their function on inflammation suppression, in order to pick up the most suitable LDH for nerve repair and regeneration. Then use LDH carrying nerve relevant factors to form the most appropriate LDH-factor composite nanoparticles. Furthermore, this project will evaluate the in vivo and in vitro neural regeneration and repair using behavioral tests, electrophysiological experimental and histopathology approach, and will also use RNA sequencing and bioinformatics analysis to reveal the key pathways of LDH with different metal cations on improving microenvironment and activate NSCs, as well as the key genes of LDH-factor on SCI repair.

脊髓损伤修复是医学领域亟待解决的难题之一，恶劣的损伤区微环境导致神经元死亡，阻碍神经干细胞（NSCs）分化形成新生神经元，如何改善损伤区微环境，促进NSCs的有效分化是脊髓损伤修复的关键科学问题。纳米层状双氢氧化物（LDH）生物相容性好，可抑制炎症，并能维持干细胞干性，在脊髓损伤修复方面有很大的应用潜力，但其层板组成具有多种选择，需要对其进行进一步设计和优化。本课题将制备一系列由不同的金属阳离子组成的LDH，对其进行物化表征，并研究其促进NSCs的增殖、迁移和分化，以及抑制炎症的作用，筛选出最适用于神经修复再生的LDH，搭载优选的神经因子，构建最适LDH-因子纳米复合体系，并在体内外开展行为学、电生理学和病理组织学神经损伤再生修复评估，进一步通过RNA测序结合生物信息学分析，解析金属阳离子影响LDH改善微环境和激活干细胞的关键分子机制，明确LDH-因子修复脊髓损伤的关键基因。

脊髓损伤修复异常困难，其中的关键科学问题是如何调控关键细胞命运。本项目聚焦于研制和优化生物材料和小分子药物及因子的合成方案，有效调控干细胞命运，促进损伤神经再生，修复脊髓损伤；（1）构建了纳米材料、小分子药物复合制剂，增强了小分子药物对体外神经元氧化损伤模型及小鼠氧化应激中枢神经系统损伤模型的神经保护作用。（2）利用小分子药物、神经因子、激素，以及层状双氢氧化物纳米材料等不同形式的诱导方式诱导神经干细胞的分化，并建立基于深度学习的预测干细胞命运的高通量检测手段，为筛选用于脊髓损伤修复的生物材料和细胞因子打下基础。（3）通过改变合成方案得到不同结构的LDHs新型纳米材料，通过促进内源性神经干细胞分化为神经元，促进脊髓损伤后轴突再生和神经修复。揭示了Mg-Fe LDHs修复脊髓损伤的分子机制，为材料的进一步优化和后续临床转化提供了一定的理论基础和现实依据。本研究研制出的系列安全有效的可移植材料，已完成其在小鼠体内的相关研究，为后续在高级哺乳类，灵长类动物体内的相关研究，乃至临床转化提供一定的现实依据和启示，为生物活性材料修复脊髓损伤修复的技术和理论发展打下坚实基础。