罗汉果基于AMPK-TLR4信号标本兼治肺纤维化的物质基础和作用机制研究

The treatment of pulmonary fibrosis (PF) has been always a worldwide problem. Inhibition promoting fibrosis cell factors on the synergy of multiple targets in different signaling pathways is a new trend of PF treatment. According to the traditional Chinese Medicines’ theory of the exterior-interior relationship between lung and intestine, regulation on the axis of intestine- immune systems-lung is helpful to treat PF from roots causes. The fruits of Siraitia grosvenorii is a traditional Chinese herbs for respiratory diseases. Our previous work indicated that the extract of Siraitia grosvenorii, distributed in lung and intestine channels, could effectively relieve symptoms of PF in mice. As main components, mogrosides significantly disturbed LPS binding TLR4 receptor, and intracellular AMPK may be related with active metabolite mogrol and its hydroxylated derivatives. According to these findings, this project intends to find out the mechanism of double targets of AMPK and TLR4 involved in mogrosides and its metabolites regulation in the process of PF on the base of structure-activity relationship of mogrosides, especially the mechanisms of mogrosides blocking pulmonary fibrosis through multi target regulation on the immunity balance. These result would indicate the molecular mechanism of mogrosides. The network research based on regulating AMPK and TLR4 signals would supports strongly the multtargets research of modern Chinese herbs, and provides a new drug design to treat PF by an intestinal–immunologic balance–lung axis.

肺纤维疾病属人类难治性疾病之一，开展有效治疗药物的研究充满挑战。基于传统中医的脏腑整体理论，中药从肠-肺系统与呼吸疾病的联系入手显著改善肺纤维化的进程。罗汉果为润肺止咳的传统中药，归肺、大肠经。本课题基于罗汉果总苷提取物改善实验性肺纤维化的研究发现，确定罗汉果苷及其苷元可能是罗汉果改善肺纤维化的主要物质基础，初步的机制研究发现肺组织分布的罗汉果苷IIIE作用于肺TLR4靶点改善肺纤维化以“治标”，在肠道内代谢成苷元罗汉果醇可通过AMPK靶点调节免疫系统以“治本”。鉴于此，本项目拟在阐明罗汉果苷成分改善肺纤维化的构-效关系基础上，以罗汉果苷IIIE和罗汉果醇为代表，用现代科学方法诠释中药罗汉果标本兼治改善实验性肺纤维化的多靶点分子机制。同时，AMPK-TLR4两条相互构成网络的信号通路研究也可为验证中药多靶点作用提供有力支持，并为肠道靶向有免疫调节作用的抗肺纤维化药物设计提供科学依据。

肺纤维疾病属人类难治性疾病之一，开展有效治疗药物的研究充满挑战。基于传统中医的脏腑整体理论，中药从肠-肺系统与呼吸疾病的联系入手显著改善肺纤维化的进程。罗汉果为润肺止咳的传统中药，归肺、大肠经。本课题基于罗汉果总苷提取物改善实验性肺纤维化的研究发现，确定罗汉果苷及其苷元可能是罗汉果改善肺纤维化的主要物质基础，证实了在不同生长时期罗汉果苷的种类及含量有较大差异。罗汉果苷类成分（罗汉果苷IIIE、罗汉果苷IIE、罗汉果苷IVE）及其苷元和代谢产物（罗汉果醇、泻根甜苷元）均可明显改善实验性肺损伤和肺纤维化。罗汉果苷激活AMPK能力与其糖链长短有关，罗汉果苷IIIE、罗汉果IIE、罗汉果醇和泻根甜苷元作为AMPK激活剂，可明显抑制TLR4蛋白异常表达且下调TGF-1/Smad介导的促纤维化信号，同时改善肠道中IL-17表达及Th1/Th2平衡以缓解肺部炎症。药理机制研究发现肺组织分布的罗汉果苷IIIE作用于肺TLR4靶点改善肺损伤及纤维化进程以“治标”，罗汉果苷类又在在肠道内代谢成次生苷及苷元罗汉果醇（或泻根甜苷元）等，可通过AMPK靶点调节免疫系统以“治本”。 本项目诠释了罗汉果苷类标本兼治改善肺纤维化的作用机制：即罗汉果苷及其苷元一方面通过激活AMPK改善肠道炎症和调节机体能量代谢而免疫调节肺纤维化——治本虚；另一方面通过抑制LPS/TLR4信号轴直接阻止肺组织炎症反应——治标实。在阐明罗汉果苷成分改善肺纤维化的构-效关系基础上，以罗汉果苷IIIE和罗汉果醇为代表，用现代科学方法诠释中药罗汉果标本兼治改善实验性肺纤维化的多靶点分子机制。同时，AMPK-TLR4两条相互构成网络的信号通路研究也可为验证中药多靶点作用提供有力支持，并为肠道靶向有免疫调节作用的抗肺纤维化药物设计提供科学依据。本项目不仅阐明药食同源中药罗汉果及活性成分罗汉果苷改善肺纤维化的作用模式和机制，还为研制高效低毒小分子抗肺纤维化药物或功能食品提供新方案。