Preclinical Development of Khellin Analogs for Anti-Diabetic Therapy

摘要 2 型糖尿病 (T2D) 影响全球超过 3 亿人。 β细胞功能障碍和 死亡是 1 型和 2 型糖尿病发病机制的关键因素。内质网 (ER) 压力在β细胞衰退中起着重要作用。因此，针对 ER 应激介导的 β 细胞的药物 功能障碍和死亡可能为糖尿病提供新的治疗途径。不过，目前还没有 批准的药物可以直接提高β细胞的存活率。我们利用了高通量筛选 (HTS) 方法成功识别了保护 β 细胞免受 ER 应激诱导死亡的小分子。在 这笔资助，我们将重点关注其中一个有效的热门产品，即用于先导优化和临床前的天然产品 Khellin 研究。我们的研究表明，(a) 在基于细胞的检测中，Khellin 可以保护 β 细胞免受 ER 应激和 通过调节内质网应激相关基因的表达，糖毒性诱导功能障碍和死亡 (b) Khellin 延迟或预防糖尿病前期动物高血糖的发生并降低血糖 通过保护 β 细胞的功能和存活来降低糖尿病动物体内的葡萄糖含量，以及 (c) β 细胞保护作用 Khellin 的作用是通过抑制硫氧还蛋白相互作用蛋白 (TXNIP) 的表达来介导的，TXNIP 是一种接头蛋白 将内质网应激、氧化应激和炎症与细胞死亡联系起来的蛋白质。尽管具有体内功效， Khellin 难溶于水，口服生物利用度差，仅在高微摩尔浓度下才有活性 浓度。因此，需要先导化合物优化来识别具有更好效力的 Khellin 类似物 和药理特性。在本提案中，我们的目标是确定能够降低血糖的类似物 糖尿病动物（表型目标）通过保护 β 细胞功能和存活（细胞目标） 调节参与 ER 应激反应（途径目标）的 TXNIP 表达，改善 理化和药代动力学特性，将药物靶标整合到有机体、细胞、 和信号通路水平，每个水平均在本 RFA 中指定。为了实现这些，我们计划 1) 合成 Khelin 类似物以提高其在基于细胞的测定中促进 β 细胞存活的生物效力及其对 关键 ER 应激标记物的表达，特别是 TXNIP； 2) 它们的药理特性，如 通过药物代谢和药代动力学 (DMPK) 研究证明； 3）他们改善的能力 动物糖尿病模型中的高血糖和β细胞保护。为了开发这些一流的化合物，我们 将使用一种将迭代和并行药物化学与体外和体内功效相结合的方法 和 DMPK 研究以及计算 PK 和药效 (PD) 模型，以确保最 有效利用时间。

Abstract Type 2 Diabetes (T2D) affects more than 300 million individuals globally. Beta cell dysfunction and death are key elements in the pathogenesis of both type 1 and type 2 diabetes. Endoplasmic reticulum (ER) stress plays important role in this beta cell decline. Therefore, drugs that target ER stress-mediated β cell dysfunction and death could provide a new therapeutic avenue for diabetes. However, there are currently no approved drugs that directly improve the survival of β cells. We have utilized a high throughput screening (HTS) approach to successfully identify small molecules that protect β cell from ER stress-induced death. In this grant, we will focus on one of the potent hits, a natural product Khellin for lead optimization and preclinical studies. Our studies revealed that (a) in cell-based assays, Khellin protects β cells against ER stress- and glucotoxicity-induced dysfunction and death by modulating the expression of genes involved in ER stress responses, (b) Khellin delays or prevents the onset of hyperglycemia in prediabetic animals and lowers blood glucose in diabetic animals by protecting the function and survival of β cells, and (c) the β cell-protective effect of Khellin is mediated by suppression of the expression of thioredoxin-interacting protein (TXNIP), an adaptor protein that connects ER stress, oxidative stress, and inflammation with cell death. Despite its in vivo efficacy, Khellin is poorly soluble in water, has poor oral bioavailability, and is only active at high micromolar concentrations. Therefore, lead optimization will be necessary to identify Khellin analogs with better potency and pharmacological property. In this proposal, our goal is to identify such analogs that lower blood glucose in diabetic animals (phenotypic target) by protecting β cell function and survival (cellular target) through the modulation of expression of TXNIP involved in ER stress response (pathway target), with improved physicochemical and pharmacokinetic properties, an effort integrating drug targets at the organismal, cellular, and signaling pathway levels, each as specified in this RFA. To achieve these, we plan to 1) synthesize Khelin analogs to improve their biological potency in promoting β cell survival in cell-based assays and their effect on expression of key ER stress markers, TXNIP in particular; 2) their pharmacological properties, as demonstrated by drug metabolism and pharmacokinetic (DMPK) studies; and 3) their ability to ameliorate hyperglycemia and β cell protection in animal diabetes models. To develop these first-in-class compounds, we will use an approach that integrates iterative and parallel medicinal chemistry with in vitro and in vivo efficacy and DMPK studies as well as a computational PK and pharmacodynamic (PD) modeling to ensure the most efficient use of time.