Department of Neurochemistry, Inge Grundke-Iqbal Research Floor, New York State Institute for Basic Research in Developmental Disabilities, Staten Island, NY, USA.
Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education of China, Nantong University, Nantong, Jiangsu, China.
J Alzheimers Dis. 2021;79(4):1647-1659. doi: 10.3233/JAD-201290.
Neurofibrillary pathology of abnormally hyperphosphorylated tau spreads along neuroanatomical connections, underlying the progression of Alzheimer's disease (AD). The propagation of tau pathology to axonally connected brain regions inevitably involves trafficking of seeding-competent tau within the axonal compartment of the neuron.
To determine the seeding activity of tau in cerebral gray and white matters of AD.
Levels of total tau, hyperphosphorylation of tau, and SDS- and β-mercaptoethanol-resistant high molecular weight tau (HMW-tau) in crude extracts from gray and white matters of AD frontal lobes were analyzed by immuno-blots. Tau seeding activity was quantitatively assessed by measuring RIPA buffer-insoluble tau in HEK-293FT/tau151-391 cells treated with brain extracts.
We found a comparable level of soluble tau in gray matter versus white matter of control brains, but a higher level of soluble tau in gray matter than white matter of AD brains. In AD brains, tau is hyperphosphorylated in both gray and white matters, with a higher level in the former. The extracts of both gray and white matters of AD brains seeded tau aggregation in HEK-293FT/tau151-391 cells but the white matter showed less potency. Seeding activity of tau in brain extracts was positively correlated with the levels of tau hyperphosphorylation and HMW-tau. RIPA-insoluble tau, but not RIPA-soluble tau, was hyperphosphorylated tau at multiple sites.
Both gray and white matters of AD brain contain seeding-competent tau that can template aggregation of hyperphosphorylated tau, but the seeding potency is markedly higher in gray matter than in white matter.
异常过度磷酸化的 tau 的神经纤维缠结沿着神经解剖连接扩散，这是阿尔茨海默病（AD）进展的基础。tau 病理学向轴突连接的脑区传播不可避免地涉及到在神经元的轴突隔室内运输有种子能力的 tau。
确定 AD 大脑灰质和白质中 tau 的种子活性。
通过免疫印迹分析 AD 额叶大脑灰质和白质粗提物中总 tau、tau 过度磷酸化以及 SDS 和 β-巯基乙醇抗性高分子量 tau（HMW-tau）的水平。通过测量用脑提取物处理的 HEK-293FT/tau151-391 细胞中 RIPA 缓冲液不溶性 tau，定量评估 tau 种子活性。
我们发现对照脑灰质与白质中的可溶性 tau 水平相当，但 AD 脑灰质中的可溶性 tau 水平高于白质。在 AD 脑中，tau 在灰质和白质中均过度磷酸化，前者水平更高。AD 脑的灰质和白质提取物均可在 HEK-293FT/tau151-391 细胞中引发 tau 聚集，但白质的效力较低。脑提取物中 tau 的种子活性与 tau 过度磷酸化和 HMW-tau 的水平呈正相关。RIPA 不溶性 tau 而不是 RIPA 可溶性 tau 在多个位点发生过度磷酸化。
AD 脑的灰质和白质均含有有种子能力的 tau，可模板聚集过度磷酸化的 tau，但灰质中的种子活性明显高于白质。
