Small molecule inhibitors of group II introns for treatment of fungal infections

 描述（由申请人提供）：该项目将导致开发针对真菌和酵母代谢特异性的新型酶靶点的有效新抑制剂： 第二组自我剪接内含子。这种结构复杂且高度保守的核酶在低等真核生物的RNA加工和代谢功能中起着关键作用，但它不存在于人类和其他脊椎动物中。因此，II组内含子抑制剂提出了一种特异性的和潜在的强大的新方法，用于对抗病原性真菌和酵母，这代表了一个主要的公共卫生问题，治疗策略越来越受到限制。事实上，真菌感染是艾滋病患者、新生儿患者的死亡率和发病率的主要来源，并且随着这些病原体的多样化，甚至在未受感染的普通人群中也是如此。广泛的生物化学研究已经导致在一个完整的酶学框架组II内含子核酶，和组II内含子结构在多个阶段的剪接已彻底通过晶体学的特点。有了这个基础，现在可以启动一个药物发现计划，旨在确定这个有前途的新靶点的有效小分子抑制剂。基于最初的小分子筛选工作（产生Ki值为2 - 8 µ M的抑制剂），我们将合成下一个 化合物的生成，通过分子支架的迭代修饰和结构引导的SAR来优化至少两种类型的初始先导物。小分子设计和合成将以快速顺序进行，随后进行生物化学和基于细胞的分析，以评价效价和疗效。我们在第一阶段的目标是确定新的第二组抑制剂， Ki值<200 nM，以评估其对致病性真菌和细菌（其还含有II组内含子）生长的影响，并评估化合物在哺乳动物细胞中的毒性。这些重点目标的完成将为II组内含子抗真菌治疗的后续2期项目提供坚实的基础。

 DESCRIPTION (provided by applicant): This project will result in the development of potent new inhibitors for a novel enzyme target that is specific to the metabolism of fungi and yeast: the group II self-splicing intron. This structurally complex and highly conserved ribozyme plays a key role in RNA processing and metabolic function of lower eukaryotes, but it is not present in humans and other vertebrates. Group II intron inhibitors therefore present a specific and potentially powerful new approach for combating pathogenic fungi and yeast, which represent a major public health problem for which therapeutic strategies are increasingly limited. Indeed, fungal infections are a major source of mortality and morbidity among AIDS patients, neonatal patients, and as these pathogens diversify, even among the noncompromised general population. Extensive biochemical studies have resulted in a complete enzymological framework for group II intron ribozymes, and group II intron structures in multiple stages of splicing have been thoroughly characterized through crystallography. With this groundwork in place, it is now possible to initiate a drug discovery program that is designed to identify potent small molecule inhibitors of this promising and novel target. Building on initial small molecule screening efforts (which yielded inhibitors with Ki values of 2-8 µM), we will synthesize the next generation of compounds, optimizing at least two types of initial leads through iterative modification of molecular scaffolds and structure-guided SAR. Small molecule design and synthesis will be done in rapid sequence with subsequent biochemical and cell-based analyses to evaluate potency and efficacy. Our goal in Phase 1 is to identify novel group II inhibitors with Ki values of < 200 nM, to evaluate their effects on growth of pathogenic fungi and bacteria (which also contain group II introns), and to evaluate compound toxicity in mammalian cells. Completion of these focused objectives will provide a solid footing for a subsequent Phase 2 program in group II intron antifungal therapeutics.