DZNE, German Center for Neurodegenerative Diseases, Bonn, Germany; MPI for Metabolism Research, Hamburg, Germany.
DZNE, German Center for Neurodegenerative Diseases, Bonn, Germany; MPI for Metabolism Research, Hamburg, Germany.
Alzheimers Dement. 2017 Nov;13(11):1270-1291. doi: 10.1016/j.jalz.2017.04.002. Epub 2017 May 18.
Tau-mediated toxicity in Alzheimer's disease is thought to operate through low-n oligomers, rather than filamentous aggregates. However, the nature of oligomers and pathways of toxicity are poorly understood. Therefore, we investigated structural and functional aspects of highly purified oligomers of a pro-aggregant tau species.
Purified oligomers of the tau repeat domain were characterized by biophysical and structural methods. Functional aspects were investigated by cellular assays ((3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay of cell viability, lactate dehydrogenase release assay [for cell toxicity], reactive oxygen species production, and calcium assay), combined with analysis of neuronal dendritic spines exposed to oligomers.
Purified low-n oligomers are roughly globular, with sizes around 1.6 to 5.4 nm, exhibit an altered conformation, but do not have substantial β-structure. Treatment of primary neurons with oligomers impairs spine morphology and density, accompanied by increased reactive oxygen species and intracellular calcium, but without affecting cell viability (by (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay of cell viability and lactate dehydrogenase release assay [for cell toxicity]).
Tau oligomers are toxic to synapses but not lethal to cells.
阿尔茨海默病中的 Tau 介导的毒性被认为是通过低聚物，而不是丝状聚集体起作用的。然而，低聚物的性质和毒性途径还知之甚少。因此，我们研究了一种促聚集 Tau 物种的高度纯化寡聚物的结构和功能方面。
通过生物物理和结构方法对 Tau 重复结构域的纯化寡聚物进行了表征。通过细胞测定（细胞活力的 3-(4,5-二甲基噻唑-2-基)-2,5-二苯基四氮唑溴化物测定、乳酸脱氢酶释放测定[用于细胞毒性]、活性氧物质产生和钙测定）以及分析暴露于寡聚物的神经元树突棘，研究了其功能方面。
纯化的低聚物大致呈球形，大小约为 1.6 至 5.4nm，具有改变的构象，但没有大量的β结构。用寡聚物处理原代神经元会损害树突棘的形态和密度，同时增加活性氧物质和细胞内钙，但不影响细胞活力（通过 3-(4,5-二甲基噻唑-2-基)-2,5-二苯基四氮唑溴化物测定的细胞活力和乳酸脱氢酶释放测定[用于细胞毒性]）。
Tau 寡聚物对突触有毒性，但对细胞没有致死性。
