Vectorized scFv antibodies to treat tau pathology in Alzheimer's disease: enhancing epitope targeting and delivery strategies

项目总结/摘要 越来越多的证据支持tau蛋白作为细胞外蛋白的存在，以及其跨细胞的概念。 传播作为阿尔茨海默病（AD）的起始和进展的机制。在这种情况下，使用 靶向tau病理学的抗体似乎是清除AD中神经元缠结的适当方法 模型不同的实验室已经产生了大量的数据，显示tau蛋白的减少。 使用tau单克隆抗体的转基因动物模型的病理学，具有不同程度的成功 根据其靶向表位。不幸的是，传统的tau免疫疗法仅实现了 tau病理学的不完全清除，并在潜在的炎症不良反应方面存在局限性 事件、长期可持续性、合规性和成本。此外，有效的血脑屏障渗透和选择 正确的tau表位仍然是一个公开辩论的主题。 在本申请中，我们将采用scFv（单链可变片段）来靶向病理性tau。scFv是 由抗体的重链和轻链的可变区组成，通过短接头连接， 亲本单克隆抗体（mAb）的表位特异性和亲和力，但具有小得多的尺寸， 减少引发不必要的炎症反应的机会。scFv表达将由病毒载体驱动 在脑内或肌内注射后，腺相关病毒（腺相关病毒，AAV）。我们公布的数据显示， 颅内施用载体化scFv-MC 1，天然抗tau构象抗体的重组形式， mAb MC 1显著减少成年tau转基因JNPL 3小鼠中的脑病理性tau种类。 在此，我们将尝试进一步增强scFv-MC 1预防tau积聚的治疗功效 （预防范例）和减少已建立的tau病理（逆转方案）：我们将采用表位- 基于双重疗法，将scFv-MC 1与针对其他tau表位的scFv组合，根据什么 在AD病理生理学中观察到。 我们还将采用颅内或肌内双重给药策略，既满足概念验证， 翻译法 最后，我们的数据表明，小胶质细胞在摄取scFv-tau复合物中起作用，并且可以降解它，而不 明显的炎症反应在这里，我们将加深对小胶质细胞在这一过程中的作用的理解。 该提案的总体目标是开发和表征AD的新型治疗方法， tau蛋白病，目标是推进工程化抗tau抗体的外周施用，其将具有 相关的翻译潜力。

PROJECT SUMMARY/ABSTRACT Increasing evidence supports the existence of tau as an extracellular protein, and the concept of its trans-cellular propagation as a mechanism for the initiation and progression of Alzheimer's disease (AD). In this context, using antibodies to target tau pathology appeared as an appropriate approach to clear neurofibrillary tangles in AD models. A conspicuous amount of data has been produced by different laboratories showing reduction of tau pathology in transgenic animal models using tau monoclonal antibodies, with a different degree of success according to which epitopes were targeted. Unfortunately, conventional tau immunotherapy has achieved only incomplete clearance of tau pathology, and presents limitations in terms of potential inflammatory adverse events, long-term sustainability, compliance and costs. Also, effective blood brain barrier penetration and choice of the correct tau epitope are still subject of an open debate. In this application, we will employ scFv (single chain variable fragments), to target pathological tau. scFv are composed of the variable regions of the heavy and light chains of antibodies, joined by a short linker, preserving the epitope specificity and affinity of the parent monoclonal antibodies (mAb), but with a much smaller size and reduced chance of triggering unwanted inflammatory responses. scFv expression will be driven by viral vectors (adeno-associated virus, AAV) after intracerebral or intramuscular injection. Our published data show that intracranial administration of vectorized scFv-MC1, the recombinant version of the native anti-tau conformational mAb MC1, significantly reduces brain pathological tau species in adult tau transgenic JNPL3 mice. Here, we will try to further potentiate the therapeutic efficacy of scFv-MC1 preventing tau accumulation (prevention paradigm) and reducing established tau pathology (reversion protocol): we will employ an epitope- based dual therapy, combining scFv-MC1 with scFv directed against other tau epitopes, according to what observed in AD pathophysiology. We will also adopt a dual delivery strategy, intracranial or intramuscular, fulfilling both a proof of concept and a translational approach. Finally, our data show that microglia have a role in up-taking the scFv-tau complex and can degrade it, without an overt inflammatory response. Here, we will deepen our understanding of the role of microglia in this process. The overall objective of this proposal is to develop and characterize a novel therapeutic approach for AD and tauopathies, with the goal to advance peripheral administration of engineered anti-tau antibodies, which will have relevant translational potential.