Optimization of microtubule-stabilizing triazolopyrimidines as therapeutics for Alzheimer's disease and related tauopathies

项目总结 包括阿尔茨海默病(AD)在内的一组被称为tauopathy的神经退行性疾病是 特点是在脑神经元内存在由过度磷酸化形式的 Tau蛋白。Tau通常是一种与微管(MT)相关的蛋白，它似乎为MTS提供了稳定性 轴突和tau的过度磷酸化促进其与MTS和MTS的脱离和 错误折叠成寡聚体和纤维状结构。这导致MT动态增加，MT密度降低 并改变了转基因(TG)小鼠的轴突运输，有证据表明MT在 可能导致神经退化的AD大脑。我们以前演示过，管理 脑穿透性MT稳定天然产物埃博酮D(EpoD)对甘油三酯中毒小鼠的影响 几个关键终点的改善，包括MT密度的增加，轴突营养不良的减少 Tau病理和神经元丢失的降低以及认知能力的改善。尽管EpoD取得了进展 对于AD患者的小型1b期临床试验，其未来的临床进展尚不确定。因此，将会有 在确定可进行更彻底测试的替代MT稳定剂方面具有相当大的价值 在阿尔茨海默病和脊椎病患者中。在这方面，我们合成并评价了一系列非天然产物 MT稳定化合物(三氮唑嘧啶或TPD，以及苯基嘧啶)，以及对这些化合物的评价 化合物导致了对关键结构-活性关联的理解。药代动力学的评价 选定实例的(PK)和药效学(PD)简档导致识别出 最近在甘油三酯小鼠肌萎缩侧索硬化症模型中显示出非常有益的活性。我们在这个早期阶段的U01中提出 计划利用在我们最初的药物化学探索中学到的经验教训，进行高度集中的 化学优化计划，以确定适合进入IND-Enabling Pre-Enabling的候选TPD化合物 临床安全性药理学和毒理学研究。我们将在电子计算对接研究中利用 选择并优先选择可申请专利的TPD同系物，以便在已建立的细胞检测中进行活性测试。来自这些网站的数据 将利用研究来改进评分方法，并重新评估电子点击的优先顺序，从而导致 合成和生物学评价的额外迭代周期。通过以下途径确定的最活跃的化合物 这一过程将对小鼠的脑暴露进行评估，首选的例子将经历完整的PK和 警局测试。最终，将评估具有卓越PK/PD性能的少数几个类似物 小鼠的安全性/耐受性，最佳候选者进入已建立的TG小鼠的疗效研究 直立面模型。总体项目目标是确定可申请专利的首席候选人TPD，该候选人将是 有资格进入IND的研究将在完成这一早期阶段的U01计划后进行。

PROJECT SUMMARY A group of neurodegenerative diseases referred to as tauopathies, which includes Alzheimer’s disease (AD), are characterized by the presence within brain neurons of inclusions comprised of hyperphosphorylated forms of tau protein. Tau is normally a microtubule (MT)-associated protein that appears to provide stability to MTs in axons, and excessive phosphorylation of tau in tauopathies promotes its disengagement from MTs and misfolding into oligomeric and fibrillar structures. This results in increased MT dynamicity, reduced MT density and altered axonal transport in transgenic (Tg) mouse tauopathy models, with evidence of similar MT deficits in AD brain that likely contribute to neurodegeneration. We previously demonstrated that administration of the brain-penetrant MT-stabilizing natural product, epothilone D (EpoD), to Tg tauopathy mice resulted in dramatic improvements in several key endpoints, including increased MT density, reduced axonal dystrophy, diminished tau pathology and a lowering of neuron loss with improved cognitive performance. Although EpoD progressed to a small Phase 1b clinical trial in AD patients, its future clinical advancement is uncertain. Thus, there would be considerable value in identifying alternative MT-stabilizing agents that could undergo more thorough testing in AD and tauopathy patients. In this regard, we have synthesized and evaluated a series of non-natural product MT-stabilizing compounds (triazolopyrimidines or TPDs, and phenylpyrimidines), and an evaluation of these compounds has led to an understanding of key structure-activity correlates. An assessment of pharmacokinetic (PK) and pharmacodynamics (PD) profiles of select examples resulted in the identification of a lead TPD that has recently shown highly beneficial activity in a Tg mouse tauopathy model. We propose in this early-stage U01 program to utilize lessons learned in our initial medicinal chemistry exploration to conduct a highly focused chemical optimization program to identify a candidate TPD compound suitable for entry into IND-enabling pre- clinical safety pharmacology and toxicology studies. We will utilize in silico computational docking studies to select and prioritize patentable TPD congeners for activity testing in established cellular assays. Data from these studies will be utilized to refine the scoring method and re-evaluate the prioritization of in silico hits, leading to additional iterative cycles of synthesis and biological evaluations. The most active compounds identified through this process will be assessed for brain exposure in mice, and preferred examples will undergo complete PK and PD testing. Ultimately, a select few analogs with superior PK/PD properties will be assessed for safety/tolerability in mice, with the best candidate advancing to efficacy studies in an established Tg mouse tauopathy model. The overall project objective is to identify a patentable lead candidate TPD that would be eligible for entry in IND-enabling studies to be conducted after completion of this early-stage U01 program.