骨髓间充质干细胞通过TSG-6调控星形胶质细胞保护蛛网膜下腔出血后血脑屏障的研究

Subarachnoid hemorrhage (SAH) is an often-fatal stroke subtype with high rates of mortality and morbidity. Brain edema, which is closely associated with deterioration of EBI, may cause the poor prognosis in SAH. The blood–brain barrier (BBB) is mainly formed by endothelial cells with complex tight junctions and plays an important role in edema. The potential mechanism by which mesenchymal stem cells (MSCs) exert their therapeutic effect involves TSG-6 has been reported in previous research. Our previous results have confirmed that the inflammatory processes associated with BBB damage in intracerebral hemorrhage (ICH) is involved with NF-κB and MAPK signaling pathways. Astrocytes, which are widely distributed in the nervous system, play an important role in process of neuroinflammation and BBB destruction. Whether intravenous transplantation of MSCs improves BBB by regulation of astrocytes and whether the mechanism is, at least in part, related to secretion of TSG-6 in SAH, remain unclear. Therefore, we investigated the mechanism of MSCs on astrocytes by TSG-6 from cellular-level in this study. Then, SAH animal model was used to verify the vitro experiments and clarify whether TSG-6 could affect astrocytes through NF-κB and MAPK pathway in BBB protection. This strategy may be useful for future therapies targeting prevention of BBB disruption in clinical SAH patients and yield new insights into the SAH treatment.

蛛网膜下腔出血（SAH）是一种危害极大的脑血管病。脑水肿是SAH早期脑损伤（EBI）过程引起病情恶化主要原因,而血脑屏障（BBB）破坏是脑水肿主要因素。对骨髓间充质干细胞（BMSCs）研究发现，旁分泌肿瘤坏死因子诱导蛋白6（TSG-6）是其治疗重要机制。我们前期研究证实在脑出血中，与BBB破坏相关的炎症过程涉及NF-κB和MAPK信号通路。作为神经系统分布广泛的星形胶质细胞，在炎症及BBB破坏过程起重要作用；而MSCs分泌TSG-6能否通过调控星形胶质细胞保护BBB及相关机制，目前为止在SAH研究中尚无报道。因此，本课题首先于细胞水平研究TSG-6对星形胶质细胞（脂多糖激活）的调控及机制；并通过动物实验进行验证，阐明TSG-6是否通过NF-κB及MAPK通路影响星形胶质细胞并保护BBB。本项目旨在探索MSCs通过TSG-6对SAH后BBB的作用及机制，为其在SAH研究和治疗提供新思路。

基于我们前期研究基础以及对BBB保护的信号通路分析，本项目主要研究：①TSG-6表达上调和下调对活化状态星形胶质细胞的影响；②MSCs通过TSG-6；③MSCs通过旁分泌机制分泌的TSG-6对SAH后星形胶质细胞及BBB完整性影响的体内研究。④阐明TNKS1的生物学功能及其与Wnt/β-连环蛋白通路的关系。⑤研究脑出血后美金刚胺的神经血管保护机制及其对神经元一氧化氮合酶(nNOS)ser1412磷酸化的影响。主要研究结果:①骨髓间充质干细胞在体内和体内外均可通过分泌TSG-6来调节星形胶质细胞的激活，从而保护血脑屏障。②骨髓间充质干细胞分泌的TSG-6通过抑制NF-κB信号通路调控激活的星形胶质细胞，从而改善血脑屏障损伤。③TNKS1可以被看作是星形细胞瘤中Wnt/β-连环蛋白通路的正调控因子。④美金刚胺可改善神经功能缺损，减轻脑含水量、MMP-9、NLRP3、IL-1β和死亡神经元的水平。通过本项目SAH及SAH后BBB的完整性的研究对SAH的诊治和预后及致残率和死亡率的降低具有重大作用。通过本项目的研究，已发表SCI论文4篇，获得国家专利2项，还有两篇论文正在投稿。