SOCS1/3负调控TLR4/MyD88信号通路在脑缺血预适应炎症抑制中的作用研究

TLR4-MyD88 proinflammatory signaling pathway is a key factor that transforms cerebral ischemia from ischemic injury to inflammatory injury and causes aggravated cerebral injury. Cerebral ischemia preconditioning inhibites inflammatory response caused by TLR4-MyD88 pathway after cerebral ischemia, but how preconditioning induces this inhibition mechanism is not clear, Suppressor of cytokine signaling SOCS1/3 may be involved in the inhibition mechanism, and SOCS1/3 may induced by JAK/STAT pathway activated by cytokines,which are generated by moderate activation of MyD88 signaling pathway in preconditioning. JAK/STAT/SOCS and TLR4/MyD88 collaborative establish the mechanism of the inflammation inhibition cause by cerebral ischemic preconditioning. To explore the question, we use gene interference, transmembrane recombinant proteins and immunoprecipitation methods to explore if these two signaling pathways mutual regulate and induce ischemia tolerance and inflammation suppression mechanism in vivo and iv vitro model. The study of the relationship between JAK/STAT/SOCS and TLR4/MyD88 and inflammation suppression in ischemic brain in cerebral ischemic preconditioning is bound to reveal the complex network of endogenous anti-inflammatory mechanisms caused by cerebral ischemic preconditioning and provide a new target and choose for drug preconditioning.

Toll受体4介导的MyD88信号通路过度激活是脑缺血炎性损伤的关键因素，脑缺血预适应后缺血脑组织TLR4/MyD88介导的炎症反应减轻，但预适应如何介导该信号通路抑制目前并不清楚，脑组织细胞因子信号抑制分子 SOCS3和/或SOCS1可能参与了该抑制过程。在预适应期, SOCS1/3可能由TLR4-MyD88通路产生的细胞因子激活JAK/STAT途径诱导生成，继而多环节反馈抑制TLR4致炎信号通路，由此JAK/STAT/SOCS和TLR4/MyD88协同建立脑缺血预适应炎症抑制机制。我们通过基因干扰、重组蛋白转染及免疫沉淀等方法，在整体和离体脑缺血预适应模型上探讨这两条通路相互调控诱导脑缺血耐受及炎症抑制机制。脑缺血预适应中，JAK/STAT/SOCS和TLR4/MyD88及缺血脑组织炎症抑制间关系研究，将促进脑缺血预适应抗炎机制复杂网络的进一步揭示，为药物预适应提供新靶点。

脑缺血预适应是迄今发现的最为有效的神经内源性保护现象，对该内源性保护机制的探索有助于为防治脑缺血再灌注损伤找到新的突破口。脑缺血预适应后产生的少量炎性细胞因子，激活JAK2-STAT3-SOCS3信号通路，继而多环节反馈抑制TLR4-MyD88致炎信号通路，由此JAK2-STAT3-SOCS3和TLR4/MyD88协同建立脑缺血预适应炎症抑制机制。我们在整体小鼠和离体神经细胞预适应模型上探讨这两条通路相互调控诱导脑缺血预适应及炎症抑制机制。在整体短暂性缺氧预适应（HPC）及脂多糖（LPS）药物预适应模型小鼠实验过程中，预先短暂性缺氧预适应及脂多糖药物预适应过程能明显改善缺血再灌24h的小鼠神经功能缺损，减少脑梗塞体积，减少TLR4-MyD88信号通路蛋白表达及下游炎性因子的表达，抑制炎症反应实现脑缺血再灌注的神经保护作用。同时激活JAK2-STAT3-SOCS3信号通路。在预适应后再灌注损伤小鼠中，利用腺相关病毒载体系统阻断小鼠脑内SOCS3蛋白表达后，脑预适应保护作用消失，TLR4、MyD88蛋白表达增加。在离体神经细胞培养实验中，同样证实预先预适应过程能明显改善氧糖剥夺24h的神经元细胞损伤程度，抑制TLR4-MyD88信号通路，下游炎性因子的表达减少，JAK2-STAT3-SOCS3信号通路被激活。因此，预适应保护作用可能与 JAK2-STAT3-SOCS3通路、TLR4-MyD88信号通路相互调节有关。探讨脑缺血预适应如何介导脑缺血后炎症抑制反应，有助于促进发现有效的药物预适应的靶点，为脑缺血损伤等疾病的防治提供新的选择。