新型mTOR抑制剂的设计、合成及其抗急性肺损伤活性评价

Acute lung injury (ALI）or its more severe form, acute respiratory distress syndrome (ARDS), is a critical respiratory disease that leads to extremely high mortality. There are no effective small molecule drugs for ALI in clinical therapy. Our collaborators have demonstrated that inhibition of mTOR or induction of autophagy is effective to protect the LPS-induced ALI, and we have also found that 4-indolyl-pyrimidine compounds could inhibit mTOR and induce autophagy in human bronchial epithelial cells. Based on our previous findings, this project will focus on designing and constructing a library of mTOR inhibitors with chemical diversity by the methodology of rational drug design involved drug pharmacophore combination, scaffold hopping, and drug-like analysis. The target compounds will be synthesized on the basis of biological activity screening and drug-like evaluation. The structure-activity relationships will be provided by biological activity evaluation of the autophagy and mTOR inhibition at molecular and cellular levels. The potentially specific mTOR inhibitors with high activity, low toxicology, and good membrane penetrability are desired to be developed, based on their pharmacological activity in the cellular inflammatory responses and ALI model induced by LPS. This project will provide experimental evidence for the protective role of mTOR inhibitors in LPS-induced ALI, thereby shedding new lights on drug development for this disease.

急性肺损伤（ALI）以及更严重的急性呼吸窘迫综合症(ARDS)是严重危害人民健康和生命的危重与难治性呼吸系统疾病，在临床上没有可有效治疗的小分子药物。本课题合作团队前期已经证明抑制mTOR或诱导细胞自噬能有效保护内毒素LPS诱导的ALI；本课题组也已发现4-吲哚基嘧啶类小分子能在气道上皮细胞中抑制mTOR并诱导细胞自噬。本项目拟在此基础上，通过药效团杂合、分子骨架迁越、类药性分析等理性药物设计方法，实施化学结构多样性的mTOR抑制剂化合物库的设计，在初步类药性评价的基础上，定向合成目标分子。并从分子细胞水平评价目标分子抑制mTOR和诱导细胞自噬的活性，获得系统的构效关系信息；进而在LPS诱导的细胞炎症反应和ALI动物模型药效学评价的基础上，发现具有选择性高、活性强、毒性低、透膜性好的新颖mTOR抑制剂，为开发针对mTOR与细胞自噬的ALI靶向治疗药物提供有力的实验依据和新的研究思路。

急性肺损伤/急性呼吸窘迫综合征（ALI/ARDS）是临床上死亡率较高的一类疾病，目前仍没有完全有效的药物治疗方法。肺部的炎症级联反应是ALI/ARDS的主要发病机制，因此抑制炎症的级联反应是一种用于急性肺损伤治疗的有效方案。以4-吲哚基-2-氨基嘧啶为母核，通过分子相似性原理、电子等排体等药物设计，分别构建了4-吲哚基-2-芳氨基嘧啶、N-芳基-4-（1-甲基吲哚-3-基）嘧啶、酰胺基和脲基4-吲哚嘧啶、磺化5-氨基吡唑、2-磺化吡唑嘧啶和2,4-二芳氨基嘧啶类化合物库，开展此类化合物的HBE细胞毒性和LPS-诱导的HBE细胞抗炎活性以及体内抗炎活性评价，总结相应的构效关系，发现三个具有毒性低、抗炎活性好的先导化合物，为抗ALI小分子药物的发现提供良好的研究基础。另外，研究发现4-吲哚-2-芳氨基嘧啶（简称IAAP）靶向抑制溶酶体组织蛋白酶L的活性，从而缓解LPS诱导的气道炎症。体外细胞实验和体内急性肺损伤实验证实，组织蛋白酶L对 LPS 诱导的炎症反应有必不可少的介导作用。组织蛋白酶L介导 IκBα 的磷酸化，激活NF-κB信号通路。因此，抑制组织蛋白酶L的活性能有效抑制NF-κB信号通路中IκBα的磷酸化，显著抑制 LPS 诱导的炎症反应。因此，阻断组织蛋白酶L-NF-κB信号轴的新机制有望成为治疗急性肺损伤的潜在靶点。