Selective inhibitors of ubiquitin E3 ligase to treat high cholesterol

描述（由申请人提供）：高胆固醇血症是心血管疾病的主要因素。在美国，超过3500万人有高总胆固醇，因此患心脏病的风险是正常水平的两倍。低密度脂蛋白受体（LDLR）对胆固醇调节至关重要，因为LDLR突变会增加血清胆固醇水平和心血管疾病的风险。提高LDLR的水平或活性是目前市场上几种降胆固醇药物所采用的一种有效的药理机制。例如，他汀类药物抑制HMG辅酶a还原酶，从而干扰胆固醇合成，从而上调肝脏低密度脂蛋白lr活性，增加血液中低密度脂蛋白的清除率。他汀类药物被广泛使用，但在许多患者中存在不良反应；因此，目前正在寻找具有不同LDLR机制的新药，这些药物具有降低副作用的可能性和/或使用减少他汀类药物剂量的联合治疗的可能性。一种被称为Idol （LDLR的诱导降解酶；也被称为MYLIP和Mir）的泛素环指E3连接酶，在其细胞质区域泛素化LDLR，导致其降解。因此，Idol是发现降胆固醇药物的一个有希望的新靶点，因为Idol抑制剂有望增加LDLR水平。此外，Idol抑制提供了一种机制独特的途径来增加LDLR的含量/活性。该项目旨在发现Idol的小分子抑制剂，通过增加LDLR水平和增强LDL清除率来降低血清胆固醇。Progenra开发了一种新的检测方法，可以检测几乎任何E3连接酶的活性；该检测已被用于寻找选择性E3连接酶抑制剂，其中一些抑制剂处于临床前开发阶段。因此，该分析将被用于高通量发现Idol抑制剂，并将进行试点筛选，以寻找具有潜在降胆固醇治疗作用的抑制剂。这项工作将分为三个具体目标。在为期1年的I期试验中，该试验将验证自泛素化（Idol）抑制剂和已知人类Idol底物泛素化抑制剂的有效性。细胞概念的证明，然后将获得实验使用筛选抑制剂。在第二阶段，将进行更广泛的筛选和化学优化，ADME，以及概念和功效的体内验证研究，其商业目标是开发和销售具有单药或组合降胆固醇活性的药物制剂。

DESCRIPTION (provided by applicant): Hypercholesterolemia is a major factor in cardiovascular disease. In the USA, more than 35 million individuals have high total cholesterol and thus twice the normal risk of heart disease. The LDL receptor (LDLR) is critical to cholesterol regulation, as mutation of LDLR increases serum cholesterol levels and risk of cardiovascular disease. Increasing the level or activity of LDLR is an effective pharmacological mechanism employed by several cholesterol-lowering drugs now on the market. Statins, for example, inhibit HMG CoA reductase thus interfering with cholesterol synthesis, which upregulates hepatic LDLR activity and increases clearance of LDL from the bloodstream. Statins are widely prescribed, but are associated with adverse reactions in many patients; thus, new drugs of differing LDLR mechanism with reduced potential to cause side effects and/or potential for combination treatment employing reduced statin doses are currently being sought. An ubiquitin RING-finger E3 ligase known as Idol ( inducible degrader of the LDLR; also known as MYLIP and Mir), ubiquitylates LDLR on its cytoplasmic domain, resulting in its degradation. Idol is thus a promising new target for cholesterol-lowering drug discovery, as Idol inhibitors are expected to increase LDLR levels. Moreover, Idol inhibition provides a mechanistically distinct pathway to increase LDLR content/activity. The proposed project aims to discover small molecule inhibitors of Idol for lowering serum cholesterol by increasing LDLR levels and enhancing LDL clearance. Progenra has developed a novel assay that can detect the activity of virtually any E3 ligase; the assay has been used to find selective E3 ligase inhibitors, several of which are in pre-clinical development. Accordingly, the assay will be adapted and validated for high-throughput discovery of inhibitors of Idol, and a pilot screen will be conducted for inhibitors that are of potential utility as cholesterol- lowering therapeutic agents. The work will be divided into three Specific Aims. In the 1 year Phase I, the assay will be validated for inhibitors of both auto-ubiquitylation (Idol) and for inhibitors of ubiquitylation of the known substrate of human Idol. Cellular proof of concept will then be obtained experimentally using selected inhibitors from the screens. In Phase II, a more extensive screen and chemical optimization, ADME, and in vivo proof of concept and efficacy studies will be conducted, with the commercial goal of developing and marketing a pharmaceutical agent with single agent or combinatorial cholesterol lowering activity. PUBLIC HEALTH RELEVANCE: Elevated blood cholesterol is a major factor in cardiovascular disease; in the USA this condition affects more than 35 million individuals, who accordingly face increased risk of developing heart disease. The current drug of choice for lowering cholesterol is the family of statins, which work by increasing the binding of "bad" cholesterol to its receptors and thereby promote clearance of cholesterol from the bloodstream. Although widely prescribed, statins are associated with adverse reactions in many patients; thus, new drugs that would either work by a mechanism that leads to fewer or less severe side effects than those produced by the statins or be usable as part of a combination treatment regimen are currently being sought. Progenra has identified a promising new target for cholesterol-lowering drug discovery, an enzyme known as Idol, which conjugates ubiquitin to bad cholesterol receptors (LDLR), marking the receptor for degradation in the proteasome. Inhibitors of this target are expected to increase LDLR levels by preventing degradation of the receptor. Progenra will adapt and validate an assay for high throughput screening for inhibitors of Idol, screen its compound collection, and demonstrate that inhibitors from the screen affect LDLR in cells as predicted. In Phase II, selected inhibitors will undergo pre-clinical development, with the commercial goal of developing and marketing a pharmaceutical agent with single agent or combinatorial cholesterol lowering activity.