基于IL-33/ST2通路探讨温肾方调控哮喘免疫失衡的机制研究

The researchers discovered recently, IL-33 which is released from epithelial cells, binding to the ligand ST2, mediate T lymphocyte immune imbalance and innate immune response, which plays an important role in the starting asthma. Our previous research discovered Wenshen Formula can significantly reduce IL-33 levels in the serum of patients with asthma, downregulate the expression of splenic dendritic cells (DCs) in asthmatic mice.On account of the discovery, what is the downstream of Wenshen Formula regulating IL-33 pathway? its main role in subsequent adoptive immunotherapy or innate immunity, is the important content for us to study and reveal..Through establishing asthmatic animal model with different pathogenesis (allergic asthma model mediated by DCs and innate immune damage asthma model and IL-33 blockade asthma model), and through DCs interacting with Th cells in vitro, and culturing innate immune cells (ILC2) in vitro, This study is aimed to explore wheather the immune-pathway is mediated though IL-33/ST2 by Wenshen Formula, wheather DCs are a major role in regulating Th lymphocyte differentiation imbalance, or by regulating the innate immune function, to play the role of anti-asthma; while to explore Wenshen Formula's Protective effects of airway mucosal barrier, thus providing a new target and the theoretical basis for the prevention and treatment of asthma of traditional Chinese medicine.

研究者新近发现，上皮细胞释放的IL-33,与配体ST2结合，介导T淋巴细胞免疫失衡和固有免疫反应，它是启动和介导哮喘免疫应答的关键靶点。我们前期发现温肾方能降低哮喘患者血清IL-33水平；下调哮喘小鼠脾脏树突细胞（DCs）表达。基于这一发现，温肾方调控的下游机制如何？是通过作用于后续的获得性免疫，还是固有免疫（IC2）通路，是我们要揭示的重要内容。.本研究拟通过建立不同发病机制的哮喘动物模型（DCs介导的过敏性哮喘模型和固有免疫损伤引起的哮喘模型及IL-33阻断模型），并通过体外培养DCs与Th细胞相互作用，及体外诱导培养固有免疫细胞（ILC2），探讨温肾方是否主要通过IL-33/ST2途径介导免疫应答；是主要作用于DCs调节Th淋巴细胞分化失衡，抑或是通过调节固有免疫细胞的功能，来发挥抗哮喘的作用；同时探讨温肾方对气道粘膜屏障的保护作用，从而为温肾法防治哮喘提供新的靶点和理论依据。

本研究通过体内建立获得性免疫相关的OVA诱导的哮喘动物模型，及IL-33 诱导的固有免疫优势哮喘小鼠模型，及观察温肾方对体外细胞培养的DC、DC和T共培养体系的干预作用。研究发现：.在获得性免疫方面（1）温肾方可降低气道高反应性；下调BALF中炎性细胞数量，对中性粒细胞的抑制温肾方具有独特优势；（2）温肾方可下调IL-4,IL-5,IL-13 和血清IgE，纠正Th1/Th2失衡状态，抑制IL-33/ST2信号通路；（3）温肾方可下调DC表面共刺激分子，抑制DC抗原递呈功能，进而纠正Th1/Th2分化失衡；.在固有免疫方面：（1）温肾方高剂量组可明显下调BALF 中IL-33的表达，优于西药地塞米松组。（2）温肾方可下调肺组织ILC2的表达及ILC2的表面受体（ICOS 受体、ST2受体）及转录因子RORα、GATA-3的表达; 并通过抑制STAT5的磷酸化水平，抑制ICOS受体，从而抑制ILC2的表达和功能；（3）此外，温肾方能独特的上调ILC1、ILC3的转录因子（T-bet），及上调IFN-γ分泌因子，而激素治疗组未见此效应，提示温肾方可能在调控固有免疫应答ILCs平衡方面、调控固有淋巴样细胞的功能方面具有独特的优势，值得进一步深入研究和挖掘，为温肾方防治哮喘提供了新的靶点和理论依据。.结论：温肾方可抑制哮喘小鼠获得性免疫和固有免疫的两个方面，尤其在调控固有免疫方面具有独特的优势。进一步深入探讨温肾方如何通过调控固有免疫机制来控制哮喘，以及对固有淋巴样细胞（ILCs）系统平衡的调节作用，对哮喘的防治具有重要的意义。温肾方可改善哮喘气道病理、保护气道黏膜的完整性，其对气道黏膜屏障的保护作用以及对固有免疫的优势调控作用，体现了哮喘“肺肾相关、隐性虚损”的病理本质。