IL-33/ST2信号通路在低氧促进干细胞修复周围神经损伤中的双向作用及调控

One of the difficulties faced by Hand Surgery Department is the poor functional recovery caused by many factors during the repair of peripheral nerve injury. Nowadays, the application of multi-pluripotent stem cells to repair injured nerve and reconstruct the nerve function is the most promising treatments. The stem cell state is coordinately regulated by hypoxia and high level of injury-related factors in the microenvironment. Our previous study has found that hypoxia could obviously up-regulated the level of neural progenitor cell (NPC) marker genes and the transmembrane receptor ST2 of injury-related factor IL-33 during the differentiation of induced pluripotent stem cell (iPSC) towards NPC. Thus, we suspect hypoxia may regulate the differentiation of iPSC towards NPC through activating IL-33/ST2 signaling pathway. In this research, we verified the regulation of hypoxia to IL-33/ST2 pathway and the important role of this pathway in the process of iPSC differentiating into NPC by the methods of chromatin immunoprecipitation, oligonucleotide-directed mutagenesis and gene knockout. Meanwhile, we’ll establish a model of peripheral nerve injury in rats, clarifying the feasibility of promoting the capability of iPSC to repair of peripheral nerves by intervening IL-33/ST2 pathway, which will provide a theoretical basis for a more efficient use of stem cells to repair peripheral nerve.

周围神经损伤修复可由多种因素导致功能恢复不佳，是手外科面临的难题之一。应用干细胞的多向分化潜能对受损神经进行修复和功能重建是目前最有前景的治疗手段，而干细胞在损伤部位的状态则受到微环境中低氧及高水平损伤相关因子协同调控。我们前期研究发现，在诱导性多能干细胞（iPSC）向神经祖细胞（NPC）分化过程中，低氧明显上调NPC标志性基因及损伤相关因子IL-33的受体ST2的表达，故推测低氧可能通过活化IL-33/ST2信号通路调控iPSC向神经祖细胞分化。本研究通过染色质免疫共沉淀、定点突变及基因敲除等方法验证低氧对IL-33/ST2通路的调控及此信号通路在iPSC向神经祖细胞分化过程中的重要性。同时我们将建立大鼠周围神经损伤模型，通过体内实验阐明通过干预IL-33/ST2通路促进iPSC修复受损外周神经的可行性，为更高效的利用干细胞进行周围神经修复提供理论依据。

周围神经损伤修复可由多种因素导致功能恢复不佳，是手外科面临的难题之一。应用干细胞的多向分化潜能对受损神经进行修复和功能重建是目前最有前景的治疗手段，而干细胞在损伤部位的状态则受到微环境中低氧及高水平损伤相关因子协同调控。我们前期研究发现，在诱导性多能干细胞（iPSC）向神经祖细胞（NPC）分化过程中，低氧明显上调NPC标志性基因及损伤相关因子IL-33的受体ST2的表达，故推测低氧可能通过活化IL-33/ST2信号通路调控iPSC向神经祖细胞分化。.本项目主要研究低氧及其相关的IL-33/ST2通路对间充质干细胞UCMSC向神经元样细胞分化的影响，为了解决UCMSC应用过程中出现的分化效率和增殖能力减弱的问题，我们也对UCMSC的衰老相关机制进行了研究。我们发现低氧能够促进UCMSC分化并直接上调IL-33和ST2的表达，而激活IL-33/ST2通路也可促进UCMSC向神经元样细胞分化，这为通过体外刺激更高效的利用干细胞修复损伤神经提供理论基础。同时，我们在体外细胞衰老体系中证明了可通过干预线粒体呼吸链相关基因COX2（mtCOX2）的甲基化来抑制UCMSC衰老，为解决干细胞组织修复过程中生存时间短、分化能力有限问题提供解决方案。