鼻粘膜外胚间充质干细胞通过Connexin43调控Hippo通路抑制脑出血后星形胶质细胞活化的研究

Neuroinflamation induced by astrocytes (ASC) activation after intracerebral hemorrhage (ICH) has been demonstrated as one of the mechanisms causing neurological deterioration. Inflammatory micro-environment can also inhibit the survival and differentiation of transplanted cells. As a novel adult stem cell, ecto-mesenchymal stem cell (EMSC) can be isolated from nasal mucosa, oral mucosa and dental pulp. It can be easily cultured in vitro. It helps to overcome the ethical bottleneck of translational research which limits clinical application of neural stem cells and mesenchymal stem cells in the past. Most recent research revealed the immunomodulation function of EMSC. Previously we have studied in detail the mechanisms of neural injury caused by iron overload after ICH. Recently we found Connexin43 (Cx43) was richly expressed in EMSC and ASC, Cx43 based gap junction can be built between these two cells. However, Cx43 was downregulated after ICH. Based on these findings, we come up with this proposal. We will explore the mechanism of ASC activation after ferrous chloride treatment. Then verify that EMSC can inhibit iron overload induced ASC activation by Cx43 based modulation of Hippo pathway. Furthermore, EMSC will be transplanted into ICH mice brain. Improvement of the inflammatory micro-environment, maintenance of blood brain barrier, protection of remaining neurons and amelioration of neurological deficit will be evaluated. This project is designed to clarify the immunomodulatory mechanism of EMSC on ICH induced ASC activation. It helps to promote transformation application of EMSC and provides immunomodulatory therapy strategy for ICH.

脑出血（ICH）后星形胶质细胞（ASC）活化引起炎症反应是加重神经损伤的重要因素之一，并影响移植细胞的存活与分化。外胚间充质干细胞（EMSC）作为一种成体干细胞，用于移植治疗，取材方便、合乎伦理，可克服以往干细胞转化应用的瓶颈。最新研究表明EMSC还具有免疫调节作用，但具体机制尚不明确。本项目基于ICH后铁过载损伤机制的前期研究基础，结合EMSC和ASC通过Connexin43（Cx43）建立缝隙连接及ICH后Cx43表达下调的新发现，1）探讨Fe2+对ASC的激活作用及机制，2）验证EMSC与ASC通过Cx43建立缝隙连接从而调控Hippo通路抑制Fe2+介导的ASC活化，3）在ICH模型中探讨EMSC移植对血肿周围炎症微环境的改善、血脑屏障和残存神经元的保护作用以及神经功能改善情况。本研究将有助于阐明EMSC对ICH的免疫调节机制，促进EMSC移植的转化应用，为ICH的治疗提供新思路。

脑出血（ICH）后星形胶质细胞（ASC）活化引起炎症反应是加重神经损伤的重要因素之一，并影响移植细胞的存活与分化。间充质干细胞（MSC）作为一种成体干细胞，用于移植治疗，取材方便、合乎伦理，可克服以往干细胞转化应用的瓶颈。最新研究表明EMSC还具有免疫调节作用，但具体机制尚不明确。经过该课题研究，1）体外研究部分，分别用C57BL/6J新生鼠的星形胶质细胞，以及Sprague Dawley大鼠的股骨间充质干细胞做了相关的机制研究：提示Connexin43-Hippo信号通路相关机制与星形胶质细胞的存活、增殖密切相关，而且间充质干细胞共培养后分泌的细胞因子帮助调控了该通路。通过抑制该通路可以产生抗凋亡、促增殖作用；2）体内研究部分，证实了间充质干细胞移植还通过影响脑出血周边区的星形胶质细胞抵抗氧化应激引起的继发性损伤，促进星形胶质细胞中Nrf2-HO1信号通路的激活，从而发挥神经保护作用，提示了间充质干细胞移植为脑出血后神经损伤修复提供了可能。.本研究是在细胞和动物两个水平上发掘间充质干细胞移植用于脑出血后神经功能恢复和改善的可能性，重点是调控宿主星形胶质细胞的存活和增值，并探索相关的作用机制。目前干细胞用于治疗脑血管的研究很多，但从根本上如何解决临床实际问题仍然棘手，尚不能满足转化应用的需求，而这方面正是本研究重点尝试解决的科学问题。本研究通过对Connexin43-Hippo以及Nrf2-HO1通路的研究，目前已证明其在脑出血后星形胶质细胞活化中发作重要作用，并由相关通路参与其中。该研究将成为脑血管的干细胞移植研究的重要突破。

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