树突状细胞调控脑出血后Treg/Th17细胞比例及相关炎症反应的机制

The ratio of Regulatory T (Treg) and T helper 17 (Th17) cells plays importmant roles for the regulation of inflammatory response. Our preliminary studies revealed that dendritic cells (DCs) can regulate the numbers of Treg cells after cerebral infarction. In addition, our previous research also demonstrated that the Treg/Th17 ratio decreased significantly in mice subjected to intracerebral hemorrhage (ICH). This study was designed to further evaluate the regulatory mechanism of DCs for Treg/Th17 ratio and ICH-induced inflammatory reaction in mice. Firstly, changes of Treg/Th17 ratio in the peripheral blood and brain, and neurological function will be studied by inhibiting the maturation and activation of DCs, and by antagonizing or activating the function of DC related TLR-9 and TLR-2 signal pathways after ICH in mice. And then, we will study the regulatory mechanism of DCs for Treg/Th17 ratio with the separation and culture of DCs and CD4+T cells in vitro. We intend to further recognize the pathophysiological characteristics related with changes in the Treg/Th17 ratio after ICH, and verify whether we can inhibit the ICH associated inflammatory response or improve the prognosis of ICH by regulating the function of DCs after ICH. It is great significance for the discovery of new therapeutic methods and potential therapeutic targets for ICH.

调节性T细胞（Treg细胞）与辅助性T细胞17（Th17细胞）的比例对炎症反应具有重要调节作用。申请人前期研究证实树突状细胞具有调控脑梗死后Treg细胞数量的作用，且脑出血后存在Treg/Th17细胞比例的下降。为评价树突状细胞调控脑出血后Treg/Th17细胞比例及相关炎症反应的机制，本项目拟首先抑制脑出血小鼠体内树突状细胞的成熟与活化，并在体内拮抗或激动树突状细胞相关的TLR-2/9受体通路，研究外周血及脑部Treg/Th17细胞比例、脑部炎症反应、神经功能等的改变；然后分离培养小鼠外周血树突状细胞与CD4+T细胞，体外研究树突状细胞调控Treg/Th17细胞比例的机制。拟通过上述研究深入认识与脑出血后Treg/Th17细胞比例变化有关的病理生理特点，论证能否通过调控树突状细胞的功能达到抑制脑出血相关炎症反应、改善脑出血预后的目的，本研究有利于发现脑出血新的治疗手段及可能治疗靶点。

脑出血是严重危害人类健康的疾病之一，血肿崩解产物促发的炎症反应等在血脑屏障破坏、脑水肿发生、神经细胞坏死与凋亡过程中发挥重要作用，是致残、致死的重要原因，但目前尚缺乏有效的治疗手段。近年研究表明，调节性T细胞（Treg 细胞）与辅助性T细胞17（Th17细胞）的比例对炎症反应具有重要的调节作用，脑出血后存在Treg/Th17细胞比例的下降，而且树突状细胞具有调控脑梗死后Treg细胞数量的作用。为评价树突状细胞的成熟程度等对脑出血后Treg/Th17细胞比例的调节作用及其可能机制，本项目首先通过流式细胞术与实时荧光定量PCR等技术在脑出血动物模型上评价了树突状细胞的成熟程度对Treg、Th17细胞的比例及两者比值的影响。然后通过流式细胞术与实时荧光定量PCR等技术评价了树突状细胞能否通过TLR-9/IDO通路和TLR-2/MAPK通路调节Treg/Th17细胞的比例；并通过组织染色技术和行为学评价等方式研究了树突状细胞成熟程度、Treg/Th17细胞比例的变化对脑出血急性期血肿体积、出血脑部炎症细胞的活化与聚集、神经元变性程度、脑含水量、远期脑部残余病灶体积、脑白质损伤程度和神经功能的影响。研究发现树突状细胞能够通过TLR-9/IDO 和TLR-2通路调节脑出血后Treg/Th17细胞的比例，进而调节出血脑部的免疫炎性反应和远期神经功能。本项目深入研究了树突状细胞调控脑出血后Treg/Th17 细胞比例的机制及Treg/Th17 细胞比例的失衡对出血脑部免疫炎性反应等的影响，发现了TLR-4、TLR-9/IDO/GCN2 与TLR-2/MAPK 信号传导途径等与出血脑部免疫炎性反应调节相关的关键作用靶点，为寻找脑出血治疗的新靶点提供了重要的理论依据，为相应的转化医学研究奠定了基础。