Therapeutic delivery of single chain antibody for Alzheimer's disease

描述（由申请人提供）：阿尔茨海默病（AD）是60岁后痴呆症的最常见原因。AD的病理学特征包括淀粉样肽（A）在神经炎斑块和脑血管中的沉积、神经纤维缠结和神经元丢失。越来越多的证据支持A？及其前体在AD发病机制中起重要作用的观点。用合成的A <$免疫AD小鼠模型减少了A <$沉积并减弱了它们的记忆和学习缺陷。然而，最近的临床试验由于脑炎症而停止，推测是由T细胞介导和/或Fc介导的免疫应答诱导的。在AD小鼠模型中，外周给予抗A？抗体也诱导了预先存在的淀粉样斑块的清除，表明主动T细胞介导的免疫应答是不必要的。在AD小鼠模型中，局部应用不含Fc的抗A抗体的F（ab '）2导致淀粉样蛋白沉积物的清除，表明非Fc介导的机制参与了清除。尽管这些被动免疫方式可有效治疗AD患者而不诱导副作用如炎症反应，但此类方式遭受抗体的重复施用，导致AD患者的巨大经济和身体负担。我们假设抗A？单链抗体（scFv）在治疗AD小鼠模型中是有效和安全的。我们建议使用三种不同血清型的编码抗A <$scFv的重组腺相关病毒（rAAV）载体来优化抗A <$scFv递送在降低脑A <$负荷和改善行为缺陷方面的功效。这项研究将作为原理证明，证明这种基因治疗方式是否可以将抗A ² scFvs递送到许多大脑区域，以减少A ²负荷并改善AD模型小鼠的学习和记忆缺陷。将进行以下具体目标以优化抗A scFv的预防性和治疗性递送。在目的1中，我们将通过在C57 BL/6小鼠中单次脑室内注射编码抗A <$scFv的rAAV 1、rAAV 8或AAV 9来评估scFv递送的表达和细胞毒性，以优化抗A <$scFv的颅内递送。在目的2中，我们将评估在AD小鼠模型中脑室内注射优化的编码抗A <$scFv的rAAV的预防和治疗效果。我们利用神经病理学，生物化学，免疫学和行为分析，以确定预防和治疗效果和安全的方式。长期目标是为开发安全有效的AD抗A <$抗体给药系统奠定逻辑基础。AD是老年痴呆症最常见的病因。然而，迄今为止，没有令人满意的治疗AD。这项研究将作为一个原则的证明，以证明我们的新的免疫基因治疗模式的治疗性抗体输送是有效的治疗AD的动物模型。公共卫生

DESCRIPTION (provided by applicant): Alzheimer's disease (AD) is the most common cause of dementia after the age of 60. The pathological hallmarks of AD include deposition of amyloid ¿-peptide (A¿) in neuritic plaques and cerebral blood vessels, neurofibrillary tangles, and loss of neurons. Increasing evidence supports the notion that A¿ and its precursor play important roles in the pathogenesis of AD. Immunization of mouse models of AD with synthetic A¿ reduces A¿ deposits and attenuates their memory and learning deficits. Recent clinical trials, however, were halted due to brain inflammation, presumably induced by T-cell mediated and/or Fc-mediated immune responses. Peripheral administration of antibodies against A¿ also induced clearance of preexisting amyloid plaques in AD mouse models, indicating that an active T-cell-mediated immune response is unnecessary. Topical application of the F(ab')2 without Fc of antibodies against A¿ led to clearance of amyloid deposits in an AD mouse model, indicating that non-Fc-mediated mechanisms are involved in the clearance. Although these passive immunization modalities may be effective in treating AD patients without inducing side effects such as inflammatory responses, such modalities suffer from repeated administrations of antibodies, leading to a large financial and physical burden to AD patients. We hypothesize that single chain antibodies (scFvs) against A¿ are effective and safe in treating AD mouse models. We propose to optimize the efficacy of anti-A¿ scFv delivery in reducing cerebral A¿ load and improving behavioral deficits using three deferent serotypes of recombinant adeno-associated virus (rAAV) vectors encoding anti-A¿ scFv. This study will serve as a proof of principle to demonstrate if this gene therapy modality can deliver anti-A¿ scFvs to many brain regions to reduce A¿ load and improve learning and memory deficits in AD model mice. The following specific aims will be carried out in order to optimize prophylactic and therapeutic delivery of anti-A¿ scFv. In Aim 1, we will evaluate expression and cytotoxicity of scFv delivery by a single intracerebroventricular injection of rAAV1, rAAV8, or AAV9 encoding anti-A¿ scFv in C57BL/6 mice to optimize intracranial delivery of anti-A¿ scFv. In Aim 2, we will evaluate prophylactic and therapeutic effects of intracerebroventricular injections of optimized rAAV encoding anti-A¿ scFv in an AD mouse model. We utilize neuropathological, biochemical, immunological, and behavioral analyses to determine the prophylactic and therapeutic effects and safety of the modality. The long-term goal is to establish the logical basis for developing safe and effective delivery systems of anti-A¿ antibody for AD. Project De isease (AD) is the most common cause of dementia in the elderly. To date, however, no satisfactory treatments are available for AD. This study will serve as a proof of principle to demonstrate if our novel immune gene therapy modality for therapeutic antibody delivery is effective in treating an animal model of AD. Public Hea