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: 10786022
• 负责人: Michael John Lucas
• 金额: $ 6.95万
• 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/10786022
• 关键词: Acceleration; 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; Sorting; Surface; Synapses; TFRC gene; Testing; Therapeutic; Therapeutic antibodies; Time; Transgenic Mice; Variant; Viral; Western Blotting; Wild Type Mouse; Work; Yeasts; age related neurodegeneration; antagonist; blood-brain barrier penetration; 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.

阿尔茨海默病（AD）是最常见的与年龄相关的神经退行性疾病。尽管伟大 生物制剂（例如治疗性抗体）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），这是其临床疗效的最大障碍。一 有前景的策略是使用双特异性抗体 BBB 穿梭，其中涉及将 IgG 与第二个亲和配体融合 它与脑血管内皮靶标结合并诱导穿过血脑屏障的转运。虽然大多数以前 工作重点是针对转铁蛋白受体 (TfR-1) 的 BBB 穿梭机，我的实验室开发了一种 BBB 穿梭机 参与 CD98hc，即大型中性氨基酸转运蛋白 (LAT-1) 的重链。值得注意的是，我们的 初步数据表明，通过 CD98hc 穿梭的 IgG 具有出色的脑实质递送和保留能力 与那些通过 TfR-1 穿梭的细胞相比。重要的是，第一代 CD98hc 穿梭机能够将 只需将单链 CD98hc 抗体连接到两个 IgG 之一的 C 末端即可获得现成的 IgG 沉重的链条。该提案的目标有两个： i) 定义最佳 CD98hc 航天飞机特性 （CD98hc 单链亲和力、价态和表位）用于最大程度的脑实质递送和保留 指导第二代CD98hc航天飞机的设计； ii) 生成概念验证功效数据 AD 小鼠模型（tau、PS19）使用 TrkB 激动剂抗体诱导神经保护信号传导。对于第一个 客观地说，我假设 BBB 与单价 CD98hc 单链抗体（如第一个- 一代穿梭机）和降低的 CD98hc 单链抗体亲和力（相对于第一代穿梭机）将 通过改善近腔处的抗体解离，最大化脑实质中的抗体浓度 大脑内皮一侧，如 TfR-1 穿梭机观察到的。对于第二个目标，我假设 将 TrkB 激动剂 IgG 递送至 tau 转基因小鼠脑实质的 CD98hc 穿梭机将减少 神经元和突触损失以及认知缺陷。这一假设得到了非非药物的部分功效的支持。 穿梭 TrkB 抗体在 AD 中进行系统性递送和 TrkB 配体的病毒脑递送的高效性 鼠标模型。因此，我在目标 1 中建议开发优化的第二代 CD98hc 航天飞机 评估 CD98hc 单链抗体亲和力、价态和表位对抗体浓度的影响 在小鼠脑实质中作为时间的函数。接下来，在目标 2 中，我建议评估第一人的能力： 一代 CD98hc 穿梭机将 TrkB 激动剂 IgG 递送至脑实质，以激活野生型中的 TrkB 和 tau (PS19) 转基因小鼠，并介导 tau 转基因小鼠的神经保护作用。一个关键的预期成果 是开发一种优化的 CD98hc 穿梭机，可用于运送各种现有的 针对脑实质的治疗性抗体。第二个关键预期结果是 TrkB 的临床前数据 AD 小鼠模型中的激动作用。这些发现有望使未来的单一和组合研究成为可能 使用针对机械独特途径的拮抗剂和激动剂抗体的疗法。