Department of Public Health and Caring Sciences/Molecular Geriatrics, Uppsala University, Uppsala, Sweden.
BioArctic, Stockholm, Sweden.
Cell Mol Neurobiol. 2017 Oct;37(7):1217-1226. doi: 10.1007/s10571-016-0454-0. Epub 2016 Dec 27.
Aggregated alpha-synuclein is the main component of Lewy bodies, intraneuronal deposits observed in Parkinson's disease and dementia with Lewy bodies. The objective of the study was to identify surface-exposed epitopes of alpha-synuclein in vitro and in vivo formed aggregates. Polyclonal immunoglobulin Y antibodies were raised against short linear peptides of the alpha-synuclein molecule. An epitope in the N-terminal region (1-10) and all C-terminal epitopes (90-140) were found to be exposed in an indirect enzyme-linked immunosorbent assay (ELISA) using recombinant monomeric, oligomeric, and fibrillar alpha-synuclein. In a phospholipid ELISA, the N-terminus and mid-region of alpha-synuclein (i.e., 1-90) were associated with phosphatidylserine and thus occluded from antibody binding. The antibodies that reacted most strongly with epitopes in the in vitro aggregates (i.e., 1-10 and epitopes between positions 90-140) also labeled alpha-synuclein inclusions in brains from transgenic (Thy-1)-h[A30P] alpha-synuclein mice and Lewy bodies and Lewy neurites in brains of patients with alpha-synucleinopathies. However, differences in reactivity were observed with the C-terminal antibodies when brain tissue from human and transgenic mice was compared. Taken together, the study shows that although similar epitopes are exposed in both in vitro and in vivo formed alpha-synuclein inclusions, structural heterogeneity can be observed between different molecular species.
聚集的α-突触核蛋白是路易体的主要成分，路易体是帕金森病和路易体痴呆中观察到的神经元内沉积物。本研究的目的是鉴定体外和体内形成的聚集物中α-突触核蛋白的表面暴露表位。针对α-突触核蛋白分子的短线性肽产生了多克隆免疫球蛋白 Y 抗体。在间接酶联免疫吸附试验（ELISA）中发现，N 端区域（1-10）和所有 C 端表位（90-140）在使用重组单体、寡聚体和纤维状α-突触核蛋白时暴露。在磷脂 ELISA 中，α-突触核蛋白的 N 端和中区域（即 1-90）与磷脂酰丝氨酸结合，因此与抗体结合被阻断。与体外聚集物中表位反应最强的抗体（即 1-10 和位置 90-140 之间的表位）也标记了转基因（Thy-1）-h[A30P]α-突触核蛋白小鼠和α-突触核蛋白病患者脑内路易体和路易神经原纤维中的α-突触核蛋白包涵体。然而，当比较人类和转基因小鼠的脑组织时，观察到 C 端抗体的反应性存在差异。总之，该研究表明，尽管体外和体内形成的α-突触核蛋白包涵体中暴露了相似的表位，但不同分子物种之间可能存在结构异质性。
