FTY720缓释膜复合iPS来源的dNSCs对脊髓损伤修复的作用和机制研究

Spinal cord injury is a major medical challenge with no effective treatment. Stem cell transplantation is a potential treatment for SCI, but the limited cell migration ability and low survival rate after transplantation is its major obstacle. Previous studies reported that systemic delivery S1P agonist FTY720 could promot SCI repair,but the mechanism was not clear, and systemic drug delivery had severe side effect. Our preliminary experiments suggested that FTY720 has different influence on cell migration ability of neural stem cells and astrocytes. Therefore, we hypothesized that combination of FTY720 administration and iPS-dNSCs implantation could promote SCI repair. The study would (1) establish iPS cells，promote the neural differentiation and assess its function, (2) reveal the regulatory mechanism of FTY720 on migration and inflammatory cytokine secretion of neural stem cells and glial cells, (3) further evaluate the efficacy and mechanism of combination therapy in rat SCI models. This study would clarify the mechanism of action of FTY720 for SCI repair, and provide new combination therapy strategies for SCI.

（400字）脊髓损伤(SCI)目前尚无有效的治疗方法。干细胞治疗（尤其是神经干细胞）具有很大潜能但疗效不满意，主要原因是损伤局部胶质疤痕增生和大量炎症反应导致移植细胞存活率低、迁移能力弱。有研究报导全身给药FTY720可促进SCI修复，但机制不清且全身给药有副反应。我们体外实验发现FTY720能显著促进神经干细胞迁移，抑制星形胶质细胞迁移。因此我们假说局部缓释FTY720复合多能干细胞来源的神经干细胞（iPS-dNSCs）能有效促进SCI修复。本研究1）建立iPS系，进行神经分化并评估其功能；2）体外研究FTY720对神经干细胞和胶质细胞的迁移和炎症因子分泌的影响和分子机制；3）采用大鼠SCI模型，通过自主研制的丝素蛋白材料缓释FTY720和联合iPS-dNSCs移植，评估其修复效果，探讨体内作用机制。本研究将阐明FTY720在SCI中的作用机制，为SCI修复提供新的治疗策略。

脊髓损伤（Spinal cord injury, SCI）是人类所经历的创伤中最具破坏性的创伤之一，临床治疗面临着巨大的困难。脊髓损伤后，细胞外S1P的表达明显升高，S1P表达升高是损伤局部炎症反应和胶质疤痕增生的重要原因，在多发性硬化症中，S1PR1敲除或者给予FTY720可有效的减少体内星形胶质疤痕的形成，最近研究表明全身给药S1P受体激动剂芬戈莫德（FTY720）具有一定的修复SCI的功能，但这一具体的药物作用机理和神经保护机制尚未阐述明确。聚已酸内酯(Polycaprolactone,PCL)是一种生物相容性高,可降解的生物材料,PCL在降解后不会酸化局部组织,因此被广泛的用作小分子药物的缓释载体。本课题着重研究局部缓释制剂FTY720-PCL膜在SCI后的修复作用及其中的潜在机制。研究发现FTY720可延长的内化S1P1,拮抗S1P1作用, 对体外星形胶质细胞增殖和迁移没有明显影响,但可以明显抑制S1P引起的星形胶质细胞的增殖和迁移。FTY720-PCL膜缓释制剂可以缓释释放FTY720约14天。缓释的FTY720可以减少SCI后星形胶质细胞标记物GFAP的表达,明显促进大鼠运动功能恢复。这些结果表明,PCL局部缓释FTY720可通过靶向星形胶质细胞的S1P1受体促进SCI恢复，为脊髓损伤治疗提供一种新的理论治疗策略。