选择性ZAKα小分子蛋白降解剂的设计、合成与生物活性研究

Leucine-zipper and sterile-α motif kinase (ZAK) is closely related to the formation and development of cardiac hypertrophy, which has been proved to be an emerging potential target for hypertrophic cardiomyopathy. The latest research reported that ZAKα and ZAKβ displayed the opposite bioactivities. ZAKα induced cardiac hypertrophy, while ZAKβ protected the heart. ZAKα and ZAKβ share the same amino acid sequence in the kinase domains, but the unique SAM domain is the specific characteristic of ZAKα. To date, no selective ZAKα inhibitor has been reported. We succussfully designed and synthetized the first selective ZAK inhibitors in our previous work. This project aims at the ZAKα-SAM domain to discover and modify for small molecular ligands with high affinity by using high throughput virtual screening and rational durg design. The ligands for ZAKα-SAM domain would be connected with different E3 ligands via covalent linkers to produce novel ZAKα small-molecule PROTACs, whose structure-activity relationships, in vitro degradation activities and in vivo anti-HCM activities would be systematically studied. It is planned to obtain novel ZAKα small-molecule PROTACs with potent biological activity and high selectivity as essential chemical tools for further exploration of the biological function of ZAKα subtype protein and the validation of ZAKα as a new drug target.

ZAK激酶在心肌肥大的形成和发展中发挥重要作用，是治疗肥厚性心肌病的潜在新靶标。最新研究发现，ZAKα与ZAKβ亚型蛋白分别介导相反的生物功能，ZAKα诱导心肌肥大形成，而ZAKβ对心脏起保护作用。ZAKα蛋白特有的SAM域片段是区分两种亚型的主要特征。目前，尚无选择性ZAKα亚型蛋白抑制剂报道。在前期工作中，我们成功设计合成了首类选择性ZAK抑制剂，本项目拟在前期工作基础上，针对ZAKα-SAM域，运用虚拟筛选、合理药物设计等方法，寻找、优化与该片段有高亲和力的小分子配体，通过共价连接链与E3连接酶配体相连，合成选择性ZAKα小分子蛋白降解剂，并对其构效关系、降解活性以及体内外抗心肌肥大活性进行系统研究，以期获得生物活性好、特异性高的ZAKα小分子蛋白降解剂，为进一步探究ZAKα亚型蛋白的生物学功能、验证其作为药物新靶标提供研究工具。

ZAK激酶在肥厚性心肌病的发生发展中发挥关键作用，是重要的潜在治疗新靶标。最新研究发现，ZAKα与ZAKβ亚型蛋白分别介导相反的生物功能，ZAKα诱导心肌肥大形成，而ZAKβ对心脏起保护作用。ZAKα蛋白特有的SAM域片段是区分两种亚型的主要特征。目前，尚无选择性ZAKα亚型蛋白抑制剂报道。在前期工作中，我们成功设计合成了首类选择性ZAK抑制剂，本研究基于报道的ZAK蛋白和抑制剂的晶体结构，采用电子等排体和基于结构优化的药物设计策略，设计并合成了一系列1,2,3-三氮唑苯磺酰胺作为新的选择性ZAK抑制剂，代表化合物10e，对ZAK具有强激酶抑制活性，IC50值为4.0 nM，并且剂量依赖性地抑制体外和体内ZAK下游信号的激活。该化合物在自发性高血压大鼠模型中表现出良好的药代动力学特性和良好前景的口服治疗效果，为发展选择性ZAK蛋白抑制剂治疗肥厚型心肌症等相关疾病的治疗提供新型药物候选化合物。