吴茱萸碱增强炎性巨噬细胞IGF-I受体磷酸化的分子机制

Evodiamine (EVO) exerts significant reversal effect on the pathological process of macrophages (Mφ) dysfunction, systemic inflammatory response syndrome (SIRS) and multiple organ dysfunction syndrome (MODS) induced by severe trauma and infectious complication. Based on our preliminary experimental finding that EVO could enhance the phosphorylation of insulin-like growth factor-I receptor (IGF-IR) in inflammatory Mφ, according to the fact that IGF-IR phosphorylation mediates the anti-inflammatory action of IGF and that aryl hydrocarbon receptor (AhR) is an important binding target of EVO, we propose the scientific hypothesis that the anti-inflammatory action of EVO is mediated by its interacting to AhR and then facilitating IGF-IR phosphorylation in inflammatory Mφ. In this study we will use LPS-stimulated murine Mφ in vitro and in vivo, corroborate whether or not the modulating effect of EVO on IGF-IR phosphorylation is dependent on AhR, investigate which downstream signal pathway of AhR mediates the above-mentioned effect of EVO, validate the members of IGF system, which are mostly altered by EVO-initiated AhR signal transduction and then induce IGF-IR phosphorylation, attempt a cooperative anti-inflammatory strategy by strengthening the modulation of EVO on the "AhR→IGF→IGF-IR axis". The results will not only help to reveal the anti-inflammatory mechanism of EVO, but also establish the foundation for the development of this novel immune response modifier in the future treatment of immune dysfunction induced by severe trauma and infectious complication.

吴茱萸碱（EVO）对严重创伤、感染所致巨噬细胞（Mφ）功能紊乱-SIRS-MODS病程具有明显的逆转效应。课题组依据前期发现"EVO可增强炎性Mφ胰岛素样生长因子-I受体（IGF-IR）磷酸化"，再结合"IGF-IR磷酸化介导了IGF的抗炎效应"以及"芳香烃受体（AhR）为EVO重要抗炎作用靶点"的事实，我们提出"EVO作用于Mφ的AhR以激活IGF-IR磷酸化进而发挥抗炎效应"的科学假设。本研究拟利用离体、在体实验中LPS激活的小鼠Mφ，明确EVO对炎性Mφ的IGF-IR磷酸化调节是否有赖于AhR存在；证实何种AhR下游信号通路介导了上述效应；确证EVO通过上述通路影响IGF系统何成员进而增强IGF-IR磷酸化；尝试增强EVO调节炎性Mφ"AhR→IGF→IGF-IR轴"的协同抗炎策略。这不仅有助于揭示EVO的抗炎作用机制，而且可为纠正创伤、感染后免疫功能紊乱的新型调节剂的研发奠定基础。

严重创伤后继发性器官损害可致脓毒症的发生, 而过度活化的巨噬细胞释放炎症介质在该病理过程中发挥重要的角色。吴茱萸碱(Evodiamine,EVO)是一种具有抗炎活性的中药单体，对严重创伤、感染所致巨噬细胞功能紊乱病程具有明显的逆转效应。芳香烃受体(Aryl hydrocarbon receptor,AhR)是配体依赖性激活的转录因子，近来研究表明其在免疫炎症调节中发挥重要作用。本研究项目结合生物信息学和体内外实验，阐明EVO可通过AhR及核因子κB (nuclear factor kappa B, NF-κB)信号通路抑制巨噬细胞炎症反应的分子机制。结果发现：（1）EVO对炎性巨噬细胞胰岛素样生长因子1受体(insulin-like growth factor receptor I,IGF-IR)磷酸化的调节，并不依赖AhR和IGF信号通路，另一方面其抗炎效应与IGF-IR磷酸化也无明显联系。（2）在小鼠体内外，EVO都能通过下调核因子κB 抑制蛋白α(NF-κB inhibitory protein α,IκBα)磷酸化水平，阻止IκBα蛋白的降解和NF-κB p65入核，从而抑制酵母多糖诱导的炎症反应，进而减轻肺和肠组织的炎性损害，提高脓毒症小鼠的生存率。（3）EVO作为AhR的天然配体，并通过AhR依赖的方式增加AhR-Stat1复合物，降低NF-κB的结合和转录活性、亲和力，进而抑制巨噬细胞IL-6的转录和表达。这些研究结果提示，EVO可通过AhR及NF-κB信号通路抑制巨噬细胞炎症反应。本研究探究EVO的药物靶点并阐明其抑制炎症反应的分子机制，不仅有助于揭示EVO对炎症损害的保护作用机制，并为脓毒症的新型免疫调节剂研发奠定基础。