Optimization and evaluation of novel benzimidazoles for the treatment of Alzheimer's Disease

项目摘要/摘要(父项目) Tau蛋白稳定神经元微管，但tau异常过度磷酸化导致聚集 队形。此外，可溶性tau中间体比高阶聚集体具有更强的神经毒性，并且 对AD患者的认知功能障碍负有责任。一种有益的AD治疗方法可能是提高tau的清除。 甲苯咪唑是一种被批准的驱虫药，可以与游离微管蛋白结合。在为期14天的概念验证研究中，我们 发现每天两次剂量的甲苯咪唑(25 mg/kg，bi.i.d.)显著降低脑组织tau蛋白水平 12周龄rTg4510小鼠大脑皮质。 虽然甲苯咪唑在人体内使用是安全的，但其溶解性、代谢稳定性和药代动力学较差， 尤其是对于一种中枢神经系统疾病，限制了其翻译治疗人类AD的潜力。因此，一个令人兴奋的 新型苯并咪唑的PK和Pd性质的药物化学优化存在机会 类似物，我们相信这将导致发现一种显著改进的分子，具有潜在的 治疗AD。这项建议的具体目标是： 目的1.微管蛋白结合、tau调节及脑组织渗透的药物化学优化 苯并咪唑。甲苯咪唑的新类似物将被设计、合成并在体外进行表征 建议书中详细描述的化验方法。化学方法侧重于增加新化合物的溶解度 分子，提高易受攻击的氨基甲酸酯和酮基团的稳定性。目标是确定 可获得专利的具有改善体外类药物性能的新型化学物质并确定最佳 化合物，以推进目标2的药代动力学和靶参与研究。 目的2.先导化合物在小鼠体内的药代动力学和靶向结合研究。主键属性 符合表3中标准1-9的化合物将在小鼠身上进行研究，那些具有 适当的血浆和脑暴露将进入体内研究，以衡量靶参与。这个 目标参与度研究的目标是确定28天剂量的铅化合物对水平的影响 在rTg4510 AD小鼠模型中：(I)脑脊液(CSF)和(Ii)脑中总tau和p-tau的含量。 目的3.先导化合物在rTg4510小鼠模型中的体内药效研究。我们将评估 在rTg4510阿尔茨海默病小鼠模型中，先导化合物在较长时间的剂量-反应效力研究中的有效性。 剂量将根据PK和目标参与度研究(目标2)确定。我们会同时研究：(I) 预防性(早期)治疗将在2个月开始，这是发病的时间点，并继续 3个月；和(2)将在5个月开始的治疗性(晚期)治疗，这是认知能力下降的开始 在8个月时结束，此时表现出非常严重的认知障碍病理。我们的目标是确定一个 含铅化合物：(I)显著降低大脑皮层和海马区tau和p-tau水平；(Ii) 突触和神经元标记的改善；以及(Iii)记忆和学习的恢复。 1

Project Summary/Abstract (Parent Project) Tau protein stabilizes microtubules in neurons, but abnormal hyperphosphorylation of tau leads to aggregate formation. In addition, soluble tau intermediates are more neurotoxic than higher order aggregates, and are responsible for the cognitive dysfunction in AD. A beneficial AD treatment may be to enhance tau clearance. Mebendazole is an approved anthelmintic drug that binds to free tubulin. In a 14-day proof of concept study, we discovered that twice daily dosing of mebendazole (25 mg/kg, b.i.d.) significantly lowered tau protein levels in the cortex of 12 week old rTG4510 mice. Although mebendazole is used safely in humans, its poor solubility, metabolic stability, and pharmacokinetics, in particular for a CNS disease, limits its potential for translation to treat AD in human. Therefore, an exciting opportunity exists for medicinal chemistry optimization of both the PK and PD properties of novel benzimidazole analogs, which we believe will result in the discovery of a significantly improved molecule with the potential to treat AD. The specific aims to this proposal are: Aim 1. Medicinal chemistry optimization of tubulin binding, tau modulation and brain penetration of novel benzimidazoles. New analogs of mebendazole will be designed, synthesized, and characterized in the in vitro assays described in detail in the proposal. Chemistry approaches focus on increasing the solubility of new molecules and improving the stability of the vulnerable carbamate and ketone groups. Goals are to identify patentable novel chemical matter with improved in vitro drug-like properties and to determine the best compounds to advance to the Aim 2 pharmacokinetic and target engagement studies. Aim 2. Pharmacokinetics and target engagement studies of lead compounds in mice. The PK properties of compounds that satisfy the criteria 1-9 in Table 3 will be studied in mice, and those compounds with appropriate plasma and brain exposure will advance into in vivo studies to measure target engagement. The goal of the target engagement studies is to determine the effect of 28-day dosing of lead compounds on levels of total tau and p-tau in: (i) cerebrospinal fluid (CSF); and (ii) brain in the rTG4510 mouse model of AD. Aim 3. In vivo efficacy studies of the lead compounds in the rTG4510 mouse model. We will evaluate the efficacy of the lead compound in a longer, dose-response efficacy study in the rTG4510 mouse model of AD. Dosing will be determined from the PK and target engagement studies (Aim 2). We will study both: (i) preventative (early) treatment that will begin at 2 months, which is the time point of onset pathology, and continue for 3 months; and (ii) therapeutic (late) treatment that will start at 5 months, which is the start of cognitive decline ending at 8 months, when very severe pathology with cognitive deficits are exhibited. The goal is to identify a lead compound that gives: (i) a significant reduction in tau and p-tau levels in cortex and hippocampus; (ii) improvements in synaptic and neuronal markers; and (iii) restoration of memory and learning. 1