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，目前的治疗方法仅 最近针对淀粉样蛋白-β (Aβ) 产生或的临床试验的结果提供了轻微的症状改善。 清除结果令人失望，促使人们重新审视 AD 治疗方法。 患者表现出神经酰胺的积累，神经酰胺是一种信号分子，也是外泌体的组成部分 神经酰胺的主要来源之一是通过中性催化的鞘磷脂水解。 尽管神经酰胺通过 nSMase2 上调而短暂增加。 是正常大脑功能的一部分，实验证据表明，慢性 nSMase2 上调会导致 最近的研究表明 nSMase2 存在于神经炎症和氧化应激等负面影响中。 Aβ 聚集和 tau 蛋白通过神经胶质细胞分泌的外泌体增殖。 通过遗传或药理学抑制 nSMase2 合成外泌体可阻止 Aβ 聚集 tau 蛋白在体外和体内 AD 模型中的传播，从而为 AD 治疗开辟了新途径。 不幸的是，尚无临床上有用的 nSMase2 抑制剂，目前的抑制剂效果较弱 (μM-mM)，效果较差。 我们与 NCATS 合作对人体进行了研究。 nSMase2 高通量筛选 (HTS) 超过 350,000 种化合物，对 HTS 命中进行过滤和分析。 发现第一个 nM 抑制剂 2,6-二甲氧基-4-(5-苯基-4-(噻吩-2-基)-1H-咪唑-2-基)苯酚 (DPTIP) (IC50 = 30 nM) DPTIP 被发现具有选择性并且能够剂量依赖性地抑制外泌体释放。 不幸的是，在神经胶质细胞培养物中，DPTIP 的体内清除速度很快，导致半衰期较短（t1/2 < 0.5 小时）。 且口服生物利用度较差（F<5%）。结构修饰（我们组合成了约 200 种类似物）。 鉴于其巨大的临床潜力，我们建议解决这个问题。 利用树枝状聚合物纳米粒子选择性地将 DPTIP 递送至活化的神经胶质细胞的药代动力学限制 我们的团队发现全身施用羟基末端聚（酰胺基胺）。 (PAMAM) 树枝状聚合物（大小约 4 nm）靶向受伤大脑中激活的神经胶质细胞，无需靶向 配体，在健康大脑中显示出最小的摄取，而树枝状聚合物被内吞并被保留。 大脑中激活的神经胶质细胞保持暴露超过 2 周，它们会迅速从外周清除 （血浆 t1/2 ~ 6-24 小时）我们已经在多个小型和大型中验证了大脑靶向性、安全性和有效性。 动物模型，我们的第一个树枝状聚合物产品（儿童 D-NAC）正在进行一期临床试验 脑肾上腺脑白质营养不良）在此，我们建议合成并评估体内 与 DPTIP (D-DPTIP) 缀合的两种不同大小的树枝状聚合物的药代动力学和靶标结合 通过脑成像、LC/MS 生物分析和评估口服给药后的最佳结合物。 将在两只已建立的小鼠中测试神经胶质细胞 nSMase2 活性的功能抑制的有效性和安全性 我们组建了一支经验丰富的团队，在树枝状聚合物纳米粒子方面拥有专业知识。 (Rangaramanujam)、药代动力学、生物标志物和靶标参与研究 (Rais) 和 药理学、药物发现和临床转化（Slusher）。