Regulation of Exosome Secretion as a novel therapeutic approach for Alzheimer's Disease

外泌体分泌调节作为阿尔茨海默病的新型治疗方法

• 批准号: 9770737
• 负责人: Camilo Rojas
• 金额: $ 49.24万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-09-01 至 2023-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9770737
• 关键词: 3xTg-AD mouse; Abeta synthesis; Address; Alzheimer' s Disease; Alzheimer' s disease model; Amyloid beta-Protein; Behavioral; Biochemical; Biochemistry; Biological Assay; Brain; Cells; Ceramides; Chemical Structure; Chemicals; Chemistry; Chronic; Clinical; Clinical Trials; Cognition; Cognitive; Cognitive deficits; Collaborations; Czech Republic; Disease; Disease Progression; Drug Discovery Groups; Drug Kinetics; Enzymes; Etiology; Exhibits; Future; Genetic; Goals; Human; Hydrolysis; In Vitro; Institutes; Laboratories; Link; Liver Microsomes; Membrane; Metabolic; Modeling; Molecular; Mus; Neuroglia; Neurology; Neurons; Oxidative Stress; Pathology; Patients; Penetration; Pharmaceutical Preparations; Pharmacology; Play; Regulation; Role; Senile Plaques; Series; Serum; Signaling Molecule; Solubility; Source; Sphingomyelinase; Sphingomyelins; Structure-Activity Relationship; Therapeutic; Toxic effect; Translational Research; Up-Regulation; Work; abeta accumulation; base; drug discovery; exosome; follow-up; high throughput screening; improved; in vivo; inhibitor/antagonist; lipid metabolism; mouse model; neuroinflammation; new therapeutic target; novel therapeutic intervention; pre-clinical; preclinical study; prevent; screening; small molecule libraries; tau Proteins

Project abstract Current available treatments for Alzheimer's disease (AD) only provide modest amelioration of cognitive and behavioral decline. Recent clinical trials targeting amyloid-β (Aβ) production or clearance did not show efficacy prompting a reexamination of approaches to AD treatment. Brains from AD patients have been shown to exhibit accumulation of ceramide, a signaling molecule and an integral component of exosomal membranes. One major source of ceramide is through the hydrolysis of sphingomyelin catalyzed by neutral sphingomyelinase 2 (nSmase2). Even though transient increases in ceramide through nSMase2 upregulation are part of normal brain functioning, experimental evidence indicates that chronic nSMase2 upregulation results in negative effects including neuroinflammation and oxidative stress. Recent studies also implicate nSMase2 in both Aβ aggregation and tau protein propagation through exosome secretion from neurons and glial cells. Moreover, inhibition of exosome synthesis by genetic or pharmacological inhibition of nSMAse2 significantly reduced Aβ aggregation and tau propagation both in vitro and in vivo thus opening a new avenue for AD therapeutics. While nSmase2 is emerging as an important player in AD etiology, the current armamentarium of nSMase2 inhibitors is inadequate to develop potential treatments. Currently available inhibitors have limitations including low potency (IC50's in µM level), poor solubility, and limited brain penetration. In order to address these limitations, we developed a human nSMase2 high throughput screening assay and screened over 350,000 compounds which led to the identification of several hits belonging to different chemical series. Early optimization of two of these hits from different chemical series led to two potent compounds with IC50s of 50 and 300 nM. Both of these compounds were confirmed as inhibitors of exosome release and exhibited good pharmacokinetic profiles and brain penetration (AUCbrain/AUCplasma = 0.27 and 0.6). The objective of this proposal is to further optimize these nSMase2 inhibitors to identify a potent, selective, brain penetrable candidate to carry out proof of concept before future IND enablement studies and ultimately for treatment of patients with AD. Aim 1 is to conduct structure-activity relationship studies to improve potency. Aim 2 is to characterize the compounds from aim 1 for functional inhibition of exosome release, metabolic stability, selectivity and in vivo pharmacokinetics. Aim 3 is to carry out in vivo proof of concept studies by evaluating selected compounds in the 3xTg mouse model of AD. The work proposed involves a novel therapeutic target which is mechanistically distinct from previous efforts in AD treatment, has the potential of addressing disease progression, and exploits two newly discovered chemical series of drug-like nSMase2 inhibitors.

项目摘要 目前可用于阿尔茨海默病（AD）的治疗仅提供认知功能的适度改善。 和行为衰退。最近针对淀粉样蛋白β（A β）产生或清除的临床试验并未显示 有效性促使对AD治疗方法进行重新检查。AD患者的大脑 显示出神经酰胺的积累，神经酰胺是信号分子和外泌体的组成部分 膜。神经酰胺的一个主要来源是通过中性蛋白酶催化鞘磷脂的水解， 鞘磷脂酶2（nSmase 2）。即使通过nSM酶2神经酰胺一过性增加， 上调是正常脑功能的一部分，实验证据表明，慢性nSM酶2 上调导致包括神经炎症和氧化应激在内的负面作用。最近的研究 也暗示nSMase2通过外泌体分泌参与A β聚集和tau蛋白增殖 神经元和神经胶质细胞。此外，通过遗传或药理学方法抑制外泌体合成是可能的。 抑制nSMAse 2可显著降低体外和体内A β聚集和tau蛋白增殖 从而为AD治疗开辟了新的途径。虽然nSmase 2正在成为AD的重要参与者， 由于nSMase 2抑制剂的病因学，目前的药物不足以开发潜在的治疗方法。 目前可用的抑制剂具有局限性，包括效力低（IC50以μ M水平计）、溶解性差和 有限的大脑渗透。为了解决这些局限性，我们开发了一种人nSMase 2高 通量筛选试验，筛选了超过350，000种化合物， 几个不同化学系列的样本早期优化的两个这些命中从不同的 化学系列产生了两种有效的化合物，IC50为50和300 nM。这两种化合物都是 证实为外泌体释放的抑制剂，并表现出良好的药代动力学特征， 渗透率（AUC脑/AUC血浆= 0.27和0.6）。本提案的目的是进一步优化这些 nSMase2抑制剂，以确定一种有效的、选择性的、可穿透大脑的候选药物，以进行概念验证 在未来的IND启动研究之前，并最终用于治疗AD患者。目标1： 结构-活性关系研究以提高效力。目的二是对目标化合物进行结构表征 1用于功能性抑制外来体释放、代谢稳定性、选择性和体内药代动力学。 目的3是通过在3xTg小鼠中评价所选化合物来进行体内概念验证研究 AD模型提出的工作涉及一种新的治疗靶点，其机制不同于 先前在AD治疗中的努力，具有解决疾病进展的潜力，并利用了两个 新发现的药物样nSMase2抑制剂的化学系列。