Department of Cancer Biology and Pharmacology, University of Illinois College of Medicine at Peoria, P.O. Box 1649, Peoria, IL, 61656, USA.
J Mol Neurosci. 2013 Feb;49(2):277-88. doi: 10.1007/s12031-012-9877-3. Epub 2012 Sep 4.
We previously reported that anti-amyloid-beta (Aβ) single-chain antibody (scFv59) brain delivery via recombinant adeno-associated virus (rAAV) was effective in reducing cerebral Aβ load in an Alzheimer's disease (AD) mouse model without inducing inflammation. Here, we investigated the prophylactic effects and mechanism of a muscle-directed gene therapy modality in an AD mouse model. We injected rAAV serotype 1 encoding scFv59 into the right thigh muscles of 3-month-old mice. Nine months later, high levels of scFv59 expression were confirmed in the thigh muscles by both immunoblotting and immunohistochemistry. As controls, model mice were similarly injected with rAAV1 encoding antihuman immunodeficiency virus Gag antibody (scFvGag). AAV1-mediated scFv59 gene delivery was effective in decreasing Aβ deposits in the brain. Compared with the scFvGag group, levels of Aβ in cerebrospinal fluid (CSF) decreased significantly while Aβ in serum tended to increase in the scFv59 group. AAV1-mediated scFv59 gene delivery may alter the equilibrium of Aβ between the blood and brain, resulting in an increased efflux of Aβ from the brain owing to antibody-mediated sequestration/clearance of peripheral Aβ. Our results suggest that muscle-directed scFv59 delivery via rAAV1 may be a prophylactic option for AD and that levels of CSF Aβ may be used to evaluate the efficacy of anti-Aβ immunotherapy.
我们之前报道过，通过重组腺相关病毒（rAAV）传递抗淀粉样蛋白-β（Aβ）单链抗体（scFv59）可有效降低阿尔茨海默病（AD）小鼠模型中的脑 Aβ 负荷，而不会引起炎症。在这里，我们研究了 AD 小鼠模型中肌肉定向基因治疗方式的预防效果和机制。我们将编码 scFv59 的 rAAV 血清型 1 注射到 3 月龄小鼠的右大腿肌肉中。9 个月后，通过免疫印迹和免疫组织化学证实 scFv59 在大腿肌肉中的表达水平很高。作为对照，模型小鼠也用编码抗人免疫缺陷病毒 Gag 抗体（scFvGag）的 rAAV1 进行相同的注射。AAV1 介导的 scFv59 基因传递可有效减少大脑中的 Aβ 沉积。与 scFvGag 组相比，scFv59 组脑脊液（CSF）中的 Aβ 水平显著降低，而血清中的 Aβ 水平则趋于升高。AAV1 介导的 scFv59 基因传递可能会改变 Aβ 在血液和大脑之间的平衡，导致由于抗体介导的外周 Aβ 的隔离/清除而使 Aβ 从大脑中的流出增加。我们的结果表明，通过 rAAV1 进行肌肉定向 scFv59 传递可能是 AD 的一种预防选择，并且 CSF Aβ 的水平可用于评估抗 Aβ 免疫疗法的疗效。
