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

项目摘要/摘要 越来越多的证据支持tau作为一种胞外蛋白的存在，以及它跨细胞的概念。 传播是阿尔茨海默病(AD)发生和发展的一种机制。在这种情况下，使用 靶向tau病理的抗体似乎是清除AD患者神经纤维缠结的合适方法 模特们。不同实验室产生的大量数据显示，tau减少了 使用tau单抗的转基因动物模型的病理学研究，取得了不同程度的成功 根据哪些表位是目标。不幸的是，传统的tau免疫疗法仅取得了 未完全清除tau病理，并在潜在炎症不良方面存在局限性。 活动、长期可持续性、合规性和成本。此外，有效的血脑屏障穿透和选择 正确的tau表位仍然是一个公开辩论的主题。 在这项应用中，我们将使用单链可变片段(ScFv)，以靶向病理性tau。ScFv是 由抗体的重链和轻链的可变区组成，由短接头连接，保存 亲本单抗(MAb)的表位特异性和亲和力，但大小和 减少了引发不必要的炎症反应的机会。单链抗体的表达将由病毒载体驱动 (腺相关病毒，AAV)在脑内或肌肉注射后。我们公布的数据显示， 脑内注射重组天然抗tau构象的载体scFv-MC1 MAb MC1，显著减少成年tau转基因JNPL3小鼠脑内病理tau的种类。 在这里，我们将努力进一步加强scFv-MC1预防tau积聚的治疗效果。 (预防范式)和减少既定的tau病理(逆转方案)：我们将使用一个表位- 基于双重治疗，结合scFv-MC1和针对其他tau表位的scFv，根据什么 在AD病理生理学中观察到。 我们还将采用双重交付策略，即颅内或肌肉内交付，既满足概念验证又满足 翻译方法。 最后，我们的数据显示，小胶质细胞在摄取scFv-tau复合体方面发挥了作用，并可以在没有 一种明显的炎症反应。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。 这项提案的总体目标是开发和表征一种新的治疗AD和 Tau病，目标是推进工程抗tau抗体的外周给药，这将有 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.