Targeting the casein kinase 1 (CK1)-like kinase Yck2 in fungal pathogenesis

摘要/摘要 真菌病原体在世界范围内对人类健康有着巨大的影响。仅在美国，血液 近几十年来，感染人数增加了200%以上，与越来越多的人患有 由于癌症、器官移植和艾滋病毒的治疗而导致的免疫功能受损。临床表现不佳 大多数侵袭性真菌感染的结果可归因于有效的抗真菌药物的数量非常有限 对它们所针对的三种主要作用模式中的每一种都出现了临床耐药。 在各种疾病的药物开发中，蛋白激酶已成为富有回报的目标， 从癌症到新陈代谢紊乱，但作为一类，在 寻找新的抗真菌药物。为了填补这一空白，我们测试了一组特征良好、结构多样的 对人类最常见的真菌--白色念珠菌耐药分离株的抑制作用 病原体。这一筛选鉴定了几种对白色念珠菌有活性的化合物和新兴的 病原菌为金黄色念珠菌。利用化学基因组方法，我们建立了我们最重要的 活性化合物如YK2，广泛表达的酪蛋白激酶1(CK1)家族的真菌成员。vbl.使用 基因技术，我们证实了YKK2是在寄主相关条件下培养生长所必需的，是 在培养中维持棘球菌素抗性所需，并使抗棘球菌素的C. 免疫功能正常和免疫功能低下的小鼠体内都有白色念珠菌。现在，我们将利用选择性句柄 通过与我们的铅和其他几种抑制剂形成的络合物中YKK2激酶结构域的共晶结构揭示 以优化效力、真菌选择性和药理特性。将两个脚手架平行作为 降低风险战略，我们的目标是为临床药物的未来开发提供一个或多个先进的线索 候选人。为了实现这一目标，我们的多学科团队将利用其在化学、结构生物学、 药理学和真菌生物学追求以下目标： 目标1：结构使能合成具有更高抗真菌活性的YKK2抑制剂 目的2：优化真菌YKK2抑制剂的细胞和整体药理作用 目的3：通过耐药临床试验评价小鼠系统性真菌感染模型的耐受性和疗效 同时接受和不接受亚治疗棘球菌素治疗的分离株 我们为实现这些目标而开发的YKK2抑制剂有望在体内具有单剂活性，如 以及逆转/预防对棘球菌素的耐药性。这些化合物的开发将是无价的。 不仅从建立新的发现和发展的目标空间的角度 机制上不同的单剂抗真菌药，但也是抗药性厌恶组合的先驱 已被证明对控制其他传染病至关重要的抗真菌疗法的方法。

Summary/Abstract Fungal pathogens have an enormous impact on human health worldwide. In the U.S. alone, bloodstream infections have increased by over 200% in recent decades, associated with an increasing number of people with compromised immune function due to treatment for cancer, organ transplantation, and HIV. Poor clinical outcome for most invasive fungal infections is attributable to the very limited number of effective antifungals available and the emergence of clinical resistance to each of the three main modes of action they target. Protein kinases have emerged as richly rewarding targets in the development of drugs for diverse diseases, ranging from cancer to metabolic disorders, but kinases as a class have remained completely untapped in the quest for new antifungals. To begin to fill this void, we tested a panel of well-characterized, structurally diverse kinase inhibitors for activity against a drug-resistant isolate of Candida albicans, the most common human fungal pathogen. This screen identified several compounds which were active against C. albicans and the emerging pathogen, Candida auris. Using chemical genomic approaches, we established the primary target of our most active compounds as Yck2, a fungal member of the widely expressed casein kinase 1 (CK1) family. Using genetic techniques, we confirmed that Yck2 is required for growth in culture under host-relevant conditions, is required to maintain echinocandin-resistance in culture, and enables the virulence of echinocandin-resistant C. albicans in both immune-competent and immune-compromised mice. Now, we will exploit selectivity handles revealed by co-crystal structures of the Yck2 kinase domain in complex with our lead and several other inhibitors to optimize potency, fungal selectivity, and pharmacological properties. Pursuing two scaffolds in parallel as a de-risking strategy, our goal is to deliver one or more advanced leads for future development of a clinical drug candidate. To achieve this goal, our multidisciplinary team will use its expertise in chemistry, structural biology, pharmacology, and fungal biology to pursue the following aims: AIM 1: Structure-enabled synthesis of Yck2 inhibitors with improved antifungal activity AIM 2: Optimize cellular and whole animal pharmacology of fungal Yck2 inhibitors AIM 3: Evaluate tolerability and efficacy in mouse models of systemic fungal infection by drug-resistant clinical isolates with and without concurrent sub-therapeutic echinocandin treatment The Yck2 inhibitors we develop in achieving these aims are expected to possess single agent activity in vivo as well as reverse/prevent resistance to echinocandins. The development of these compounds will be invaluable not only from the perspective of establishing a new target space for discovery and development of mechanistically distinct single-agent antifungals but also in pioneering a resistance-aversive combination approach to antifungal therapy that has proven essential in controlling other infectious diseases.