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).

患有阿尔茨海默氏病（AD）的人数稳步上升，目前的治疗 提供较小的症状改善。最近针对淀粉样蛋白β（Aβ）产生的临床试验或 清除令人失望，促使对AD治疗方法进行了重新审查。广告中的大脑 患者表现出神经酰胺的积累，信号分子和外泌体的积分成分 膜。神经酰胺的一个主要来源是通过中性鞘磷脂的水解 鞘磷脂酶2（NSMase2）。即使通过NSMase2上调瞬时神经酰胺增加 是正常脑功能的一部分，实验证据表明慢性NSMase2上调结果 在包括神经炎症和氧化应激在内的负面影响中。最近的研究暗示了NSMase2两者 通过神经胶质细胞的外泌体分泌，Aβ聚集和tau蛋白传播。而且，抑制 通过遗传或药物抑制NSMASE2的外泌体合成可阻断Aβ聚集 在体外和体内广告模型中都在tau传播，从而为广告疗法开辟了新的途径。 不幸的是，没有临床上有用的NSMASE2抑制剂。电流抑制剂弱（µm-mm），较差 物理特性和/或脑穿透有限。与NCAT合作，我们进行了人类 NSMASE2高吞吐量屏幕（HTS）> 350,000种化合物。 HTS命中的过滤和分析导致 发现2,6-二甲氧基-4-（5-苯基-4-（硫代-2-基）-1H-imidazol -2-基）苯酚（DPTIP）第一个NM抑制剂 （IC50 = 30 nm）。发现DPTIP具有选择性，并且能够剂量依赖性地抑制外泌体释放 在神经胶质文化中。不幸的是，体内dptip暴露了快速清除率，导致半衰期短（T1/2 <0.5H） 口服生物利用度较差（F <5％）。结构修饰（我们组合成的200个类似物） 并没有导致重大改进。鉴于其巨大的临床潜力，我们建议解决 通过使用树突聚合物纳米颗粒选择性地传递dptip，以选择性地将药代动力学限制 大脑中的细胞。我们的团队发现，羟基终止的聚（amidoamine） （PAMAM）树枝状聚合物（大小约4 nm）靶标在受伤的大脑中激活的神经胶质，而无需靶向 配体，在健康的大脑中显示最少的吸收。虽然树突聚合物被内吞并保留 大脑中激活的神经胶质细胞维持暴露于2周，从周围迅速清除它们 （等离子体T1/2〜6-24 h）。我们已经验证了多个大小的大脑靶向，安全性和效率 动物模型，并在我们的第一个树枝状聚合物（童年的D-NAC）中进行了1阶段临床试验 大脑肾上腺肿瘤营养不良）。在此，我们建议合成和评估体内 两种与DPTIP（D-DPTIP）相结合的两种不同大小的树枝状聚合物的药代动力学和目标参与 遵循多重给药。通过大脑成像，LC/MS生物分析和 将测试两种已建立的小鼠的效率和安全性，对神经胶质NSMASE2活性的功能抑制作用将进行测试 AD模型。我们已经组建了一支经验丰富的团队，具体知识在树突纳米颗粒方面具有​​专业知识 （Rangaramanujam），药代动力学，生物标志物和目标参与研究（RAIS）和 药理学，药物发现和临床翻译（Slusher）。