Targeting the orphan nuclear receptor LRH-1 with small molecules

肥胖在美国日益流行，导致非酒精性脂肪性肝病（NAFLD）、心血管疾病和II型糖尿病的病例增加。这些疾病的一个共同特征是脂质和糖代谢异常。这一建议的中心是核激素受体，肝脏受体同源物1 (LRH-1)，它是脂质代谢、逆向胆固醇转运、葡萄糖感知和体内平衡的重要调节因子。因此，LRH-1代表了代谢性疾病的一个新的治疗靶点。LRH-1与磷脂（PLs）结合，并被罕见的磷脂酰磷脂酰胆碱（DLPC）激活，显示出有效的抗糖尿病作用。LRH-1受PL配体调节的发现揭示了调节LRH-1活性以治疗代谢性疾病的令人兴奋的潜力。然而，PLs不稳定，不适合临床使用，需要开发小分子激动剂。到目前为止，这已经被证明是具有挑战性的，因为很少有小分子可以从大的亲脂结合口袋中取代内源性脂质。我们实验室最近的研究表明，一类小分子具有这种能力。我们设计了具有生物活性的强效LRH-1激动剂。我们已经修改了我们最有效的激动剂，以改善它们的生物物理特性，使它们适合体内研究。由于啮齿类动物和人类LRH-1结合口袋的序列差异很小，缺乏合适的啮齿动物模型来筛选潜在的候选药物，阻碍了LRH-1激动剂作为治疗药物的进展。为了克服这一障碍，我们使用CRISPR-Cas9策略将小鼠LRH-1配体结合袋人源化。这允许由合成激动剂激活，同时最小化内源性相互作用表面的变化。这些先导化合物开发和小鼠模型生成的飞跃，结合我们对LRH-1结构和功能的深入了解，为开发代谢疾病的候选临床前LRH-1调节剂创造了理想的平台。在这里，我们开发了一种策略来定义我们的先导化合物的作用机制、靶点参与、药理学和疾病功效。在目标1中，我们生成了一种具有改进的生物物理性质的化合物，可以模拟pl样活化。我们将对这些化合物进行机理表征，以探索与不同极性基团接触PL结合位点如何改善LRH-1的激活。在目标2中，我们将从ADME的角度研究我们的先导化合物的行为。主要目的是利用我们的人源化小鼠建立化合物的可追溯性，以便建立药代动力学关系。在目标3中，我们将使用我们的人源化小鼠和饮食诱导的肥胖模型来评估我们的先导LRH-1化合物改善葡萄糖耐量和胰岛素抵抗的体内功效。

Obesity is a growing epidemic in the United States, leading to increases in cases of nonalcoholic fatty liver disease (NAFLD), cardiovascular disease, and type II diabetes. A common characteristic of these diseases is aberrant lipid and glucose metabolism. This proposal centers on the nuclear hormone receptor, Liver Receptor Homolog 1 (LRH-1), which acts as an important regulator of lipid metabolism, reverse cholesterol transport, glucose sensing, and homeostasis. As such, LRH-1 represents a novel therapeutic target for metabolic diseases. LRH-1 binds to phospholipids (PLs) and is activated by the unusual PL dilauroylphosphatidylcholine (DLPC) which shows potent anti-diabetic effects. The discovery that LRH-1 is regulated by PL ligands reveals an exciting potential to tune LRH-1 activity for the treatment of metabolic diseases. However, PLs are labile and not suitable for clinical use, necessitating the development of small molecule agonists. This has proved challenging thus far, since very few small molecules can displace endogenous lipids from the large, lipophilic binding pocket. Recent studies in our lab have characterized a class of small molecules that are capable of this feat. We have designed potent LRH-1 agonists that display biological activity. We have modified our most potent and efficacious agonists to improve their biophysical properties, making them suitable for in vivo studies. The advancement of LRH-1 agonists as therapeutics has also been hindered by the lack of appropriate rodent models to screen potential candidates due to small sequence differences in the binding pocket of rodent and human LRH-1. To overcome this barrier, we used a CRISPR-Cas9 strategy to humanize the mouse LRH-1 ligand binding pocket. This permits activation by synthetic agonists while minimizing changes to endogenous interaction surfaces. These leaps forward in lead compound development and mouse model generation, in combination with our deep knowledge of LRH-1 structure and function, create an ideal platform to develop candidate preclinical LRH-1 modulators for metabolic disease. Here, we have developed a strategy to define mechanisms of action, target engagement, pharmacology, and disease efficacy of our lead compounds. In aim 1, we generate a compound with improved biophysical properties that mimics PL-like activation. We will perform mechanistic characterization of this compounds to explore how contacting the PL- binding site with different polar moieties improves LRH-1 activation. In aim 2, we will examine the behavior of our lead compound from an ADME perspective. The primary objective will be to establish tractability of the compounds using our humanized mice, so that pharmacokinetic relationships can be established. In aim 3, we will use our humanized mice and a model of diet-induced obesity to evaluate the in vivo efficacy of our lead LRH-1 compounds to improve glucose tolerance and insulin resistance.