靶向PCSK9小分子降解剂的药物开发

Proprotein convertase subtilisin/kexin 9 (PCSK9) is the novel lipid-lowering target with better efficiency and safety, and has a very broad development and clinical application prospects. In view of the fact that most of the PCSK9 drugs on the market and under study are biological drugs, and the research and development of small molecular drugs are still in the initial stage, this project proposes to combine the DNA Encoded Library (DEL) screening and Proteolysis Targeting Chimer (PROTAC) technology for the development of small molecular targeted drugs of PCSK9. On the one hand, on the basis of the results of screening PCSK9 by DEL, we designed and synthesized 3-5 million to 100 million levels of diversity-based DEL for PCSK9. Taking advantaging of the DEL screening platform established by our team, we screened PCSK9 and obtained molecules with high affinity for PCSK9. Moreover, we carried out synthetic validation and structure-activity relationship (SAR) exploration to further optimize small molecules; On the other hand, the optimized small molecule PCSK9 binders are applied to the design and synthesis of PROTAC molecules targeting PCSK9. By investigating the effects of small molecules, ligands and ligands of E3 ligase on the activity of PROTAC molecules, a systematic SAR study is carried out in order to provide some theoretical and practical results for the rational design and synthesis of PROTAC molecules targeting PCSK9, thus promoting the development of small molecular degrader of PCSK9.

前蛋白转化酶枯草溶菌素9（PCSK9）是最新一代降脂效率与安全性更好的降脂靶点，具有极其广阔的开发和临床应用前景。本项目针对目前已上市和在研的PCSK9药物大多为生物药物，小分子药物研发尚在起步阶段的现状，提出结合核酸编码化合物库（DEL）筛选和蛋白降解靶向嵌合体（PROTAC）技术用于PCSK9的小分子靶向药物研发。一方面，在课题组已有DEL对PCSK9筛选结果的基础上，设计和合成3-5个百万到亿级别的针对PCSK9的以多样性为主的DEL，借助课题组已建立的DEL筛选平台对PCSK9进行筛选得到有亲合力的分子，并通过构效关系（SAR）的探索来进一步优化小分子；另一方面，将优化后的小分子应用到靶向PCSK9的PROTAC分子的设计合成中，通过考察小分子、连接基、E3连接酶的配体等进行系统的SAR研究，为合理设计和合成靶向PCSK9的PROTAC分子提供一些具有理论价值和实际应用价值的成果。

前蛋白转化酶枯草溶菌素9（PCSK9）是最新一代降脂效率与安全性更好的降脂靶点，本项目结合核酸编码化合物库（DEL）筛选和蛋白降解靶向嵌合体（PROTAC）技术用于PCSK9的小分子降解剂的开发。研究内容和成果包括以下三个方面：（1）构建了以三聚氯氰、苯并咪唑、氨基酸、喹唑啉-4-酮和苯并吡唑啉酮为骨架的具有多个不同结构类型的DEL。开发了核酸兼容的基于多组份反应的以喹唑啉-4-酮为核心骨架的DEL构建方法；开发了基于核酸兼容的Pictet-Spengler反应的DEL构建方法。（2）优化了基于亲和力的DEL筛选PCSK9的方法，筛选出了若干与PCSK9有结合力的分子，并通过荧光偏振、SPR等验证了所得化合物是否与PCSK9具有亲和力。（3）将优化后的小分子通过中间Linker与CRBN等的E3配体连接，合成了一类PROTAC分子。该类降解剂没有表现出明显的降解PCSK9的能力，还需要继续优化。综合以上结果，本研究为PCSK9降解剂的开发提供了一些新的具有应用价值的实验方法，尤其合成的DEL也可以应用于其他蛋白的筛选。项目资助发表SCI论文1篇，申请发明专利2项，参与培养研究生3名。