Targeting Lipid Regulation Pathways by Novel Small Molecules

摘要 心血管疾病（CVD）是世界范围内的头号死亡原因。低密度的高水平 脂蛋白（LDL），临床上称为高胆固醇血症或高脂血症，与 CVD。尽管他汀类药物治疗对许多高胆固醇血症患者非常成功，但约 20%的患者由于他汀类药物治疗的不良反应而无法达到目标LDL水平。 前蛋白转化酶枯草杆菌蛋白酶9（PCSK 9）在胆固醇稳态中起主要调节作用 并且是治疗高胆固醇血症的经验证的新治疗靶点。化合物，其抑制 PCSK 9的作用可以是独立的治疗或作为与他汀类药物的协同剂， 高胆固醇血症治疗方案。从PCSK 9基因的发现到基因组的发现， 两种针对分泌型PCSK 9蛋白的抗体药物的批准，这是对 PCSK 9的意义和重要性。然而，对PCSK 9的基础生物学的理解远远落后于 临床发展的背后。这项来自华盛顿大学Tang、Attie和Li实验室的合作提案- 麦迪逊的目的是研究新的小分子的生物学机制和蛋白质靶点， 导致PCSK 9蛋白选择性降解。我们将通过完成三个目标来实现这些目标。 具体目标：1）开发敏感的测定方法，以评估效力、细胞毒性、选择性和代谢 新的小分子PCSK 9调节剂的稳定性; 2）阐明我们的小分子PCSK 9调节剂的作用机制。 通过从转录、翻译、翻译后 3）鉴定我们的小分子PCSK 9的直接结合伴侣 调节剂与适当的化学探针，研究这种结合伴侣的生理功能， 评估其治疗潜力。这项提议是创新的，因为我们的小分子靶向PCSK 9 调节途径不同于已知的生物试剂，例如抗体和已知的天然药物。 产物，其中大部分下调PCSK 9的转录。根据初步结果，我们 假设我们的化合物通过选择性地促进PCSK 9的翻译后表达来调节其稳定性， PCSK 9的降解。我们提出了多种跨学科的方法来研究我们的小 分子影响转录、翻译、蛋白质加工和降解，以及蛋白质的分泌途径。 PCSK 9.这项研究将产生新的小分子工具，可以改变我们研究脂质调节的方式。 并且还发现了用于治疗高胆固醇血症的新的生物靶点和途径。

ABSTRACT Cardiovascular diseases (CVD) is the number one cause of death world-wide. High levels of low density lipoprotein (LDL), clinically known as hypercholesterolemia or hyperlipidemia, are strongly associated with CVD. Although statin therapy has been very successful for many patients with hypercholesterolemia, about 20% of patients are not able to achieve target LDL levels due to the adverse effects of statin therapy. Proprotein convertase subtilisin/kexin type 9 (PCSK9) plays a major regulatory role in cholesterol homeostasis and is a validated new therapeutic target for the treatment of hypercholesterolemia. Compounds that inhibit the action of PCSK9 can be stand-alone treatments or function as synergistic agents with statins in a hypercholesterolemia treatment regimen. It took only 12 years from the discovery of the PCSK9 gene to the approval of two antibody drugs against the secreted PCSK9 protein, which is a strong testimony for the significance and importance of PCSK9. However, the understanding of the basic biology of PCSK9 lags far behind the clinical development. This collaborative proposal from laboratories of Tang, Attie, and Li at UW- Madison is intended to study the biological mechanism and protein target of novel small molecules that can lead to selective degradation of PCSK9 protein. We will accomplish these objectives by completing three specific aims: 1) Develop sensitive assays to evaluate the potency, cytotoxicity, selectivity, and metabolic stability of novel small molecule PCSK9 modulators; 2) Elucidate the mechanism of action of our small molecule PCSK9 modulators by an iterative approach from transcription, translation, posttranslational modification and degradation, to secretion; 3) Identify the direct binding partner of our small molecule PCSK9 modulators with appropriate chemical probes, investigate the physiological function of this binding partner, and evaluate its therapeutic potential. This proposal is innovative because our small molecules target PCSK9 regulation pathways that are distinct from known biological reagents such as antibodies and known natural products, most of which down regulate the transcription of PCSK9. Based on our preliminary results, we hypothesize that our compounds regulate the stability of PCSK9 by selectively promoting the post-translational degradation of PCSK9. We proposed multiple interdisciplinary approaches to examine how our small molecules affect transcription, translation, protein processing and degradation, and the secretory pathway of PCSK9. The proposed study will yield novel small molecule tools that can change how we study lipid regulating pathways and also uncover new biological targets and pathways for treating hypercholesterolemia.