Efficient Brain Delivery of Neuroprotective TrkB Agonist Antibodies in Alzheimer’s Disease Using CD98hc Bispecific Shuttles

使用 CD98hc 双特异性穿梭细胞有效脑部递送神经保护性 TrkB 激动剂抗体治疗阿尔茨海默病

• 批准号: 10537474
• 负责人: Michael John Lucas
• 金额: $ 6.72万
• 依托单位: UNIVERSITY OF MICHIGAN AT ANN ARBOR
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-08-01 至 2024-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10537474
• 关键词: Affect; Affinity; Age; Agonist; Alzheimer like pathology; Alzheimer' s Disease; Alzheimer' s disease therapy; American; Amino Acid Transport System L; Animal Model; Antibodies; Antibody Affinity; Antibody Dissociations; Antibody Specificity; Area; Biological Products; Bispecific Antibodies; Blood - brain barrier anatomy; Brain; Characteristics; Cognitive deficits; Combined Modality Therapy; Data; Dementia; Development; Disease; Endothelium; Enzyme-Linked Immunosorbent Assay; Epitopes; Evaluation; Fluorescence-Activated Cell Sorting; Functional disorder; Future; Generations; Goals; Human; Immunoglobulin G; Libraries; Ligands; Mediating; Mus; Nerve Degeneration; Neurodegenerative Disorders; Neurons; Neurotrophic Tyrosine Kinase Receptor Type 2; Outcome; Pathway interactions; Patients; Proteins; Receptor Activation; Research; Side; Signal Transduction; Surface; Synapses; TFRC gene; Testing; Therapeutic; Therapeutic antibodies; Time; Transgenic Mice; Variant; Viral; Western Blotting; Wild Type Mouse; Work; Yeasts; age related neurodegeneration; antagonist; brain parenchyma; cerebrovascular; clinical efficacy; design; improved; insight; mouse model; mutant; neuroprotection; novel therapeutics; pre-clinical; preservation; prevent; small molecule therapeutics; tau Proteins; therapeutic development; therapeutic protein

Alzheimer’s disease (AD) is the most common age-related neurodegenerative disease. Despite the great potential of biologics (e.g., therapeutic antibodies) to affect AD pathophysiology, these agents are generally unable to penetrate the blood-brain barrier (BBB), which represents their biggest hurdle to clinical efficacy. One promising strategy is to use bispecific antibody BBB shuttles, which involve fusing IgGs to a second affinity ligand that engages a cerebrovascular endothelial target and induces transport across the BBB. While most previous work has focused on BBB shuttles that target transferrin receptor (TfR-1), my lab has developed a BBB shuttle that engages CD98hc, the heavy chain of the large neutral amino acid transporter (LAT-1). Notably, our preliminary data demonstrate superior brain parenchymal delivery and retention of IgGs shuttled via CD98hc as compared to those shuttled via TfR-1. Importantly, this first-generation CD98hc shuttle enables brain delivery of off-the-shelf IgGs simply by attaching a single-chain CD98hc antibody to the C-terminus of one of the two IgG heavy chains. The objectives of this proposal are twofold: i) to define the optimal CD98hc shuttle characteristics (CD98hc single-chain affinity, valency, and epitope) for maximal brain parenchymal delivery and retention to guide the design of second-generation CD98hc shuttles; and ii) to generate proof-of-concept efficacy data in an AD mouse model (tau, PS19) using a TrkB agonist antibody that induces neuroprotective signaling. For the first objective, I hypothesize that BBB shuttles with monovalent CD98hc single-chain antibodies (as used in the first- generation shuttle) and reduced CD98hc single-chain antibody affinity (relative to the first-generation shuttle) will maximize antibody concentrations in the brain parenchyma by improving antibody dissociation at the abluminal side of the brain endothelium, as observed for TfR-1 shuttles. For the second objective, I hypothesize that CD98hc shuttles that deliver TrkB agonist IgGs to the brain parenchyma of tau transgenic mice will reduce neuronal and synaptic loss and cognitive deficits. This hypothesis is supported by the partial efficacy of non- shuttled TrkB antibodies delivered systemically and high efficacy of viral brain delivery of the TrkB ligand in AD mouse models. Therefore, I propose in Aim 1 to develop an optimized second-generation CD98hc shuttle by evaluating the impact of CD98hc single-chain antibody affinity, valency, and epitope on antibody concentrations in the mouse brain parenchyma as a function of time. Next, in Aim 2, I propose to evaluate the ability of a first- generation CD98hc shuttle to deliver a TrkB agonist IgG to the brain parenchyma, to activate TrkB in wild-type and tau (PS19) transgenic mice, and to mediate neuroprotection in tau transgenic mice. A key expected outcome is the development of an optimized CD98hc shuttle that can be used to deliver a wide range of existing therapeutic antibodies to the brain parenchyma. A second key expected outcome is preclinical data for TrkB agonism in AD mouse models. These findings are expected to enable future studies of single and combination therapies using antagonist and agonist antibodies that target mechanistically unique pathways.

阿尔茨海默氏病（AD）是最常见的与年龄相关的神经退行性疾病。尽管很棒 生物制剂（例如，治疗抗体）影响AD病理生理学的潜力，这些药物通常是 无法穿透血脑屏障（BBB），这代表了其临床效率最大的障碍。一 有希望的策略是使用双特异性抗体BBB班车，涉及将IgG融合到第二个亲和力配体 这会参与脑血管内皮靶标，并引起整个BBB的运输。而大多数 工作重点是靶向转铁蛋白受体（TFR-1）的BBB班车，我的实验室已经开发了BBB班车 这与CD98HC（大型中性氨基酸转运蛋白（LAT-1）的重链）互动。值得注意的是，我们的 初步数据表明，通过CD98HC穿梭的IgG的脑部实质递送和保留率优越 与通过TFR-1穿梭的那些相比。重要的是，这款第一代CD98HC班车使大脑交付 仅通过将单链CD98HC抗体附加到两个IgG之一的C末端来实现现成的IgG 重链。该提案的目标是双重的：i）定义最佳CD98HC班车特征 （CD98HC单链亲和力，价值和表位），以最大的脑实质递送和保留为 指导第二代CD98HC班车的设计； ii）在 AD小鼠模型（TAU，PS19）使用诱导神经保护信号传导的TRKB激动剂抗体。第一个 目的，我假设具有单价CD98HC单链抗体的BBB穿梭 一代班车）和减少CD98HC单链抗体亲和力（相对于第一代班车）将 通过改善放射性抗体解离，使大脑实质中的抗体浓度最大化 TFR-1班车观察到脑内皮的一侧。对于第二个目标，我假设 将TrkB激动剂IgGs运送到tau转基因小鼠的脑实质的CD98HC班车将减少 神经元和突触损失以及认知缺陷。该假设得到了非 - 的部分效率的支持 trkb抗体全身传递和高效率的trkb配体在AD中传递 鼠标模型。因此，我在AIM 1中提议开发优化的第二代CD98HC班车 评估CD98HC单链抗体亲和力，价值和表位对抗体浓度的影响 在小鼠脑实质中，随时间的函数。接下来，在AIM 2中，我建议评估首先的能力 CD98HC一代班车将TRKB激动剂IgG传递到脑薄壁组织中，以激活野生型TrkB 和Tau（PS19）转基因小鼠，并介导Tau转基因小鼠中的神经保护作用。一个关键的预期结果 是开发优化的CD98HC班车，可用于提供广泛的现有 脑实质的治疗抗体。第二个关键预期结果是TRKB的临床前数据 广告小鼠模型中的激动剂。这些发现有望实现未来的单一和组合研究 使用靶向机械途径的拮抗剂和激动剂抗体的疗法。