Sebollela Adriano, Cline Erika N, Popova Izolda, Luo Kevin, Sun Xiaoxia, Ahn Jay, Barcelos Milena A, Bezerra Vanessa N, Lyra E Silva Natalia M, Patel Jason, Pinheiro Nathalia R, Qin Lei A, Kamel Josette M, Weng Anthea, DiNunno Nadia, Bebenek Adrian M, Velasco Pauline T, Viola Kirsten L, Lacor Pascale N, Ferreira Sergio T, Klein William L
Department of Neurobiology, Northwestern University, Evanston, Illinois, USA.
Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
J Neurochem. 2017 Sep;142(6):934-947. doi: 10.1111/jnc.14118. Epub 2017 Aug 2.
Brain accumulation of soluble oligomers of the amyloid-β peptide (AβOs) is increasingly considered a key early event in the pathogenesis of Alzheimer's disease (AD). A variety of AβO species have been identified, both in vitro and in vivo, ranging from dimers to 24mers and higher order oligomers. However, there is no consensus in the literature regarding which AβO species are most germane to AD pathogenesis. Antibodies capable of specifically recognizing defined subpopulations of AβOs would be a valuable asset in the identification, isolation, and characterization of AD-relevant AβO species. Here, we report the characterization of a human single chain antibody fragment (scFv) denoted NUsc1, one of a number of scFvs we have identified that stringently distinguish AβOs from both monomeric and fibrillar Aβ. NUsc1 readily detected AβOs previously bound to dendrites in cultured hippocampal neurons. In addition, NUsc1 blocked AβO binding and reduced AβO-induced neuronal oxidative stress and tau hyperphosphorylation in cultured neurons. NUsc1 further distinguished brain extracts from AD-transgenic mice from wild type (WT) mice, and detected endogenous AβOs in fixed AD brain tissue and AD brain extracts. Biochemical analyses indicated that NUsc1 targets a subpopulation of AβOs with apparent molecular mass greater than 50 kDa. Results indicate that NUsc1 targets a particular AβO species relevant to AD pathogenesis, and suggest that NUsc1 may constitute an effective tool for AD diagnostics and therapeutics.
淀粉样β肽（AβOs）可溶性寡聚体在大脑中的蓄积越来越被认为是阿尔茨海默病（AD）发病机制中的一个关键早期事件。在体外和体内已鉴定出多种AβO种类，范围从二聚体到24聚体以及更高阶的寡聚体。然而，关于哪种AβO种类与AD发病机制最相关，文献中尚无共识。能够特异性识别特定AβO亚群的抗体在鉴定、分离和表征与AD相关的AβO种类方面将是一项有价值的资产。在此，我们报告了一种名为NUsc1的人单链抗体片段（scFv）的表征，它是我们鉴定出的众多scFv之一，能严格区分AβO与单体和纤维状Aβ。NUsc1能轻易检测到先前与培养的海马神经元树突结合的AβO。此外，NUsc1阻断AβO结合，并降低培养神经元中AβO诱导的神经元氧化应激和tau过度磷酸化。NUsc1进一步区分了AD转基因小鼠与野生型（WT）小鼠的脑提取物，并在固定的AD脑组织和AD脑提取物中检测到内源性AβO。生化分析表明，NUsc1靶向表观分子量大于50 kDa的AβO亚群。结果表明，NUsc1靶向与AD发病机制相关的特定AβO种类，并表明NUsc1可能构成AD诊断和治疗的有效工具。
