Dendrimer-conjugated nSMase2 inhibitor as a novel therapeutic approach for Alzheimer's Disease

树枝状聚合物结合的 nSMase2 抑制剂作为阿尔茨海默病的新型治疗方法

• 批准号: 10614450
• 负责人: Rana Rais
• 金额: $ 47.14万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-05-01 至 2025-04-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10614450
• 关键词: 3xTg-AD mouse; Abeta synthesis; Address; Adrenoleukodystrophy; Alzheimer' s Disease; Alzheimer' s disease brain; Alzheimer' s disease model; Alzheimer' s disease patient; Alzheimer' s disease therapeutic; American; Animal Model; Animals; Biochemical; Biodistribution; Biogenesis; Biological Assay; Biological Availability; Biological Markers; Body Weight; Brain; Brain Injuries; Brain imaging; Cells; Ceramides; Cerebrum; Chemicals; Chemistry; Childhood; Chronic; Circulation; Clinical; Clinical Chemistry; Clinical Trials; Cognition; Cognitive; Collaborations; Data; Dendrimers; Disease; Disease Progression; Dose; Drug Kinetics; Enzymes; Etiology; Exhibits; Experimental Models; Fluorescence Spectroscopy; Future; Generations; Genetic; Half-Life; Histologic; Histology; Human; Hydrolysis; Hydroxyl Radical; In Vitro; Kinetics; Label; Ligands; Liquid substance; Mediating; Membrane; Metabolic; Methods; Microglia; Minor; Modification; Mus; N-Methylaspartate; National Center for Advancing Translational Sciences; Neuroglia; Oral; Oxidative Stress; Pathologic; Penetration; Persons; Pharmaceutical Preparations; Pharmacology; Phase I Clinical Trials; Phenols; Plasma; Play; Production; Property; Proteins; RNA; Radial; Role; Safety; Senile Plaques; Signaling Molecule; Slice; Source; Sphingomyelinase; Sphingomyelins; Stimulus; Stomach; Synapses; Testing; Therapeutic; Time; Up-Regulation; Western Blotting; Work; abeta accumulation; analog; arm; brain volume; chemical stability; clinical translation; cohort; cyanine dye 5; drug discovery; efficacy testing; esterase; exosome; experience; extracellular vesicles; high throughput analysis; high throughput screening; human old age (65+); improved; in vivo; inhibitor; liquid chromatography mass spectrometry; meter; mouse model; multidisciplinary; nanoparticle; near infrared dye; neural network; neuroinflammation; neuron loss; novel; novel therapeutic intervention; pharmacologic; reduce symptoms; response; tau Proteins; therapeutic target; treatment duration; uptake; vesicular release; water maze

The number of people suffering from Alzheimer's disease (AD) is steadily rising and current treatments only provide minor symptom amelioration. Results from recent clinical trials targeting amyloid-β (Aβ) production or clearance were disappointing, prompting a reexamination of approaches to AD treatment. Brains from AD patients 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 implicate nSMase2 in both Aβ aggregation and tau protein propagation through exosome secretion from glial cells. Moreover, inhibition of exosome synthesis by genetic or pharmacological inhibition of nSMase2 was shown to block Aβ aggregation and tau propagation in both in vitro and in vivo AD models, thus opening a new avenue for AD therapeutics. Unfortunately, there are no clinically useful nSMase2 inhibitors. Current inhibitors are weak (µM-mM) with poor physicochemical properties and/or limited brain penetration. In collaboration with NCATS we carried out a human nSMase2 high throughput screen (HTS) of >350,000 compounds. Filtering and analysis of HTS hits led to discovery of 2,6-dimethoxy-4-(5-phenyl-4-(thiophen-2-yl)-1H-imidazol -2-yl) phenol (DPTIP) the first nM inhibitor (IC50 = 30 nM). DPTIP was found to be selective and capable of dose-dependently inhibiting exosome release in glial cultures. Unfortunately, in vivo DPTIP exhibited rapid clearance resulting in a short half-life (t1/2< 0.5h) and had poor oral bioavailability (F<5%). Structural modifications (~200 analogs synthesized by our group) have not led to substantial improvements. Given its significant clinical potential, we propose to address the pharmacokinetic limitations by utilizing dendrimer nanoparticles to deliver DPTIP selectively to activated glial cells in the brain. Our team discovered that systemically-administered hydroxyl-terminated poly(amidoamine) (PAMAM) dendrimers (~4 nm in size) target activated glia in the injured brain, without the need for targeting ligands, showing minimal uptake in healthy brains. While the dendrimers are endocytosed and retained by activated glial cells in the brain maintaining exposure for >2 weeks, they are rapidly cleared from the periphery (plasma t1/2 ~ 6-24 h). We have validated the brain targeting, safety, and efficacy in multiple small and large animal models, and are in Phase 1 clinical trials with our first dendrimer product (D-NAC in childhood cerebral adrenoleukodystrophy). Herein, we propose to synthesize and evaluate the in vivo pharmacokinetics and target engagement of two differently sized dendrimers conjugated to DPTIP (D-DPTIP) following peroral administration. The optimal conjugate assessed by brain imaging, LC/MS bioanalysis, and functional inhibition of glial nSMase2 activity will be tested for efficacy and safety in two established mouse models of AD. We have assembled a highly experienced team with expertise in dendrimer nanoparticles (Rangaramanujam), pharmacokinetics, biomarkers and target engagement studies (Rais) and pharmacology, drug discovery and clinical translation (Slusher).

患有阿尔茨海默病(AD)的人数正在稳步上升，目前仅有治疗方法 提供轻微的症状改善。最近针对淀粉样蛋白-β(Aβ)产生或 清除情况令人失望，促使人们重新审查AD的治疗方法。AD患者的大脑 患者表现出神经酰胺的积累，神经酰胺是一种信号分子，也是胞外体的一个组成部分。 膜。神经酰胺的一个主要来源是通过中性酶催化的神经鞘蛋白的水解。 鞘磷脂酶2(NSmase2)。即使通过nSMase2上调导致神经酰胺的一过性增加 是正常大脑功能的一部分，实验证据表明慢性nSMase2上调的结果 在负面影响方面，包括神经炎症和氧化应激。最近的研究表明nSMase2在这两种疾病中都有作用 β聚集和tau蛋白通过神经胶质细胞分泌的外切体进行繁殖。此外，抑制 基因或药物抑制nSMase2的外切体合成可阻断β聚集 和tau在体外和体内AD模型中的繁殖，从而为AD的治疗开辟了一条新的途径。 不幸的是，目前还没有临床上有用的nSMase2抑制剂。电流缓蚀剂较弱(微米-毫米)，性能较差 物理化学性质和/或有限的脑渗透。在与NCATS的合作中，我们进行了一次人类 NSMase2高通量筛选(HTS)350,000种化合物。HTS命中的过滤和分析导致 第一种NM抑制剂2，6-dimethoxy-4-(5-phenyl-4-(thiophen-2-yl)-1H-imidazol-2-苯酚的发现 (IC50=30 NM)。DPTIP被发现是选择性的，并能够剂量依赖地抑制外切体的释放 在神经胶质培养中。不幸的是，在体内，DPTIP表现出迅速的清除，导致较短的半衰期(t1/2&lt；0.5h) 口服生物利用度较差(F&lt；5%)。结构修饰(我们小组合成了大约200个类似物)有 没有带来实质性的改善。鉴于其巨大的临床潜力，我们建议解决 树枝状大分子纳米粒选择性地将DPTIP传递给激活的神经胶质细胞的药代动力学限制 大脑中的细胞。我们的团队发现，系统地给药的端羟基聚酰胺胺 (PAMAM)树状大分子(~4 nm大小)靶向激活损伤脑组织中的神经胶质细胞，而不需要靶向 配体，在健康的大脑中表现出最低限度的摄取。而树枝状大分子被内吞并被 大脑中激活的神经胶质细胞持续暴露2周，它们迅速从外围清除 (血浆T1/2~6~24小时)。我们已经在多个大小不同的实验中验证了脑靶向性、安全性和有效性 动物模型，我们的第一个树枝状大分子产品(儿童时期的D-NAC)正处于第一阶段临床试验 脑肾上腺脑白质营养不良)。在此，我们建议在体内合成并评价 两种不同大小的DPTIP树枝状大分子(D-DPTIP)的药代动力学和靶向结合 口服给药后。通过脑成像、LC/MS生物分析和 对神经胶质细胞nSMase2活性的功能性抑制将在两只已建立的小鼠身上进行有效性和安全性测试 AD的模型。我们组建了一支经验丰富的团队，拥有树枝状大分子纳米颗粒方面的专业知识 (Rangaramanujam)、药代动力学、生物标志物和靶向参与研究(RAIS)和 药理学、药物发现和临床翻译(Slusher)。