以PI3K-Ⅲ为靶点研究青蒿琥酯治疗重症急性胰腺炎的作用机制

Mortality rate of severe acute pancreatitis (SAP) is as high as 30%; new and effective drug is needed now. Previously, we found artesunate (AS) could effectively treat SAP in mice model, and this effect was related to its inhibition on autophagy. Based on above results, we presume AS plays its treatment effect via its binding PI3K-III and then inhibiting autophagy. Therefore, the investigation will be carried out focusing on PI3K-III. Firstly, the influences of the agonist, antagonist and siRNA of PI3K-III on the effects of AS are investigated to preliminarily ascertain the mainly affected cell line and drug target in pancreatic acinar cells and macrophage experiments. Secondly, the molecular interaction between PI3K-III and AS is investigated using biosensor technology to further ascertain its target. Thirdly, the domains and key sites of PI3K-III are predicted using molecular docking experiments and then confirmed those using cells transfected with plasmids with different domains and key sites of PI3K-III in cells experiments, or using wild or mutant proteins/peptides via the molecular interaction analysis. Lastly, the influence of the agonist and antagonist of PI3K-III on the effects of AS are investigated to ascertain the drug target of AS in SAP mice model experiments. In summary, this investigation aims to elucidate the molecular mechanisms and drug-target of AS’s anti-inflammatory effect via inhibiting autophagy in order to widen the clinical application of this drug.

重症急性胰腺炎(SAP)死亡率高达30％，发现新靶点和药物具有重要意义。我们前期发现青蒿琥酯（AS）对SAP模型动物有显著治疗作用，该作用与其抑制自噬和PI3K-Ⅲ有关，推测“AS通过与PI3K-Ⅲ结合，抑制自噬，从而减轻SAP炎症反应”。因此本项目围绕PI3K-Ⅲ：⑴在胰腺腺泡细胞和巨噬细胞中研究PI3K-Ⅲ激动剂、拮抗剂和siRNA对AS作用的影响，初步明确AS抑制自噬作用的主要细胞及靶点。⑵研究AS与PI3K-Ⅲ的分子间相互作用情况，进一步确定靶点。⑶预测PI3K-Ⅲ结合AS的结构域、关键位点：构建含PI3K-Ⅲ不同结构域、位点的载体在细胞实验中确认；表达/合成野生型和突变型蛋白质/多肽，观察AS与上述蛋白/多肽亲和力的变化，明确重要的结构域、关键位点。⑷在大鼠SAP模型中观察PI3K-Ⅲ激动剂、拮抗剂对AS作用的影响，最终确定AS的作用靶点，为阐明AS治疗SAP的作用机制奠定基础。

重症急性胰腺炎（SAP）死亡率高达30％，发现新靶点和药物具有重要意义。本研究在确认青蒿琥酯（AS）对SAP模型动物具有显著治疗作用的基础上，明确该作用与其抑制PI3K-III介导的自噬密切相关，但尚不能确认该作用和AS与PI3K-III结合有关。主要结果体现在以下三点：（1）胰腺腺泡细胞释放的前炎症细胞因子水平很低，因此我们认为在SAP诱导的炎症反应中，腺泡细胞可能并不发挥重要作用，反而是巨噬细胞更为重要，因此后续的研究聚焦在巨噬细胞上。（2）AS可下调LPS诱导的TRAF6-Beclin1-PI3K-III通路表达，确认AS可通过干预TRAF6-Beclin1相互作用、抑制TRAF6对Beclin1的泛素化，从而影响Beclin1-PI3K-III核心复合物形成和PI3K-III复合物活化；（3）AS可通过抑制PI3K-III关键位点（Ser249）的磷酸化从而抑制LPS诱导的自噬通路的活化。上述结果为进一步阐明AS治疗SAP的分子作用机制奠定了基础。