基于MAPK与NF-κB信号通路的黄藤素抗急性肺损伤机制研究

Acute lung injury is a common critical illness with sudden onset, rapid progress, poor prognosis and high mortality. The current therapeutic measures and drugs are not satisfying. Therefore, there is an urgent demand for finding new therapeutic targets and drugs for acute lung injury. Fibrauretin is a natural plant drug totally developed by our country, and is considered as a plant antibiotics as it has antiinflammatory, antiviral and antibacterial activities and immunopotentiating activity. In our previous work, we found that fibrauretin reduced the mortality of mice with acute lung injury induced by LPS, reduced the permiability of pulmonary capillaries, reduced the degree of pulmonary edma and inflammation, thus ameliorated acute lung injury. Our findings suggest that fibrauretin has good potential in prevention of acute lung injury. However, the mechanism of action of fibrauretin in prevention of acute lung injury still needs further study. In this project, we will further evaluate the effect of fibrauetin in prevention of acute lung injury, explore the effect of fibrauetin on the genes and microRNAs related to MAPK and NF-κB singnal pathway during acute lung injury, so as to clarify the molecular mechanism of fibrauetin in prevention of acute lung injury and provide new drug candidate for acute lung injury and lay good scientific foundation for broadening the clinical application of fibrauetin.

急性肺损伤起病急、进展快、预后差，病死率高，是临床常见危急重症，目前治疗措施及药物效果不理想，因此寻找急性肺损伤新的治疗靶点和有效防治药物是当前亟待解决的重要问题。黄藤素是我国自行研制的纯天然植物药，因其具有抗炎、抗病毒、抗菌、增强免疫等功效，被称为植物抗生素。我们前期初步研究发现，黄藤素能够明显降低脂多糖LPS致急性肺损伤小鼠死亡率，降低肺毛细血管通透性、减轻肺水肿、肺炎症反应和肺损伤程度，提示黄藤素对急性肺损伤的防治有很大的应用潜力。然而，黄藤素防治急性肺损伤的机制有待深入研究。本研究拟在前期研究发现基础上，进一步深入评价黄藤素防治急性肺损伤的作用，探讨黄藤素对急性肺损伤时MAPK和NF-κB信号通路中相关基因和microRNA的影响，从MAPK和NF-κB信号通路阐明黄藤素防治急性肺损伤的分子机制，为急性肺损伤的防治提供新的候选药物，为拓宽黄藤素的临床应用范围提供较好的科学依据。

急性肺损伤是临床常见危急重症，起病急、进展快、预后差，病死率高，目前治疗药物效果不理想。黄藤素是我国自行研制的纯天然植物药，具有强大的抗炎作用，被称为植物抗生素。本项目在急性肺损伤小鼠模型和LPS刺激的肺泡巨噬细胞模型上，采用western blot、ELISA、免疫组织化学、microRNA芯片、病理组织学技术等，进一步评价了黄藤素防治急性肺损伤的作用，研究了黄藤素对MAPK 和NF-κ B 信号通路中相关基因和microRNA 的影响。结果发现：(1) 黄藤素具有强大的抗急性肺损伤作用。（2）黄藤素对MAPK 与NF-κB 信号通路共同的上游基因TLR4表达有明显下调作用，对NF-κB 信号通路上游基因p-IκB有明显下调作用。（3）黄藤素对NF-κB信号通路和p38MAPK信号通路的激活具有明显的抑制作用。（4）黄藤素对MAPK 与NF-κB 信号通路下游炎症细胞因子TNF-α 和 IL-1β的表达。（5）黄藤素对NF-κB 信号通路正向调控相关microRNA表达有一定的抑制作用，对MAPK信号通路正向调控相关microRNA表达有强大的抑制作用。（6）差异miRNAs的GO-pathway分析提示，黄藤素对MAPK信号通路的抑制作用是最强，对NF-κB 信号通路有一定抑制作用，提示特异性抑制MAPK信号通路是黄藤素抗急性肺损伤的主要机制，而对NF-κB 信号通路的抑制是其非特异性机制。（7）意外发现黄藤素能够诱导急性肺损伤小鼠肺毛细血管内皮细胞自噬，保护肺毛细血管完整性。（8）附带发现另一个有抗炎活性的天然产物龙胆苦苷也具有很好的抗急性肺损伤作用，对急性肺损伤向肺纤维化转归也有明显的抑制作用。本项目从MAPK 和NF-κ B 信号通路阐明了黄藤素抗急性肺损伤的分子机制，为临床治疗急性肺损伤提供了一个新的候选药物，为拓宽黄藤素的临床应用范围提供了充实的科学依据。