Unbiased high-content screening reveals Aβ- and tau-independent synaptotoxic activities in human brain homogenates from Alzheimer's patients and high-pathology controls.
Unbiased high-content screening reveals Aβ- and tau-independent synaptotoxic activities in human brain homogenates from Alzheimer's patients and high-pathology controls.
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DOI：
10.1371/journal.pone.0259335
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发表时间：
2021
期刊：
影响因子：
3.7
通讯作者：
Brody DL
中科院分区：
文献类型：
--
作者：
Jiang H;Esparza TJ;Kummer TT;Brody DL
阿尔茨海默病（AD）与脆弱大脑区域的突触丢失密切相关。假设特定的分子实体如Aβ和tau导致AD中的突触丧失，但尚未进行突触毒性活性的无偏筛选。在这里，我们进行了尺寸排阻色谱可溶性人脑匀浆AD病例，高病理非痴呆症的控制，和低病理年龄匹配的控制，使用我们的新的高含量的原代培养的神经元为基础的筛选试验。突触前和突触后毒性升高，从AD病例和高病理学非痴呆对照的匀浆在相似程度上，与更温和的突触毒性活动，从低病理学正常对照的匀浆。令人惊讶的是，在17-44 kDa大小标准品之间达到峰值的大小组分中发现了突触毒性活性，这些标准品与这些匀浆中的Aβ和tau免疫反应性物质不匹配。含有先前鉴定的高分子量可溶性淀粉样蛋白β聚集体/“低聚物”的级分在该测定中是无毒的。此外，Aβ和tau的免疫耗竭并没有降低突触毒性活性。这一结果与先前涉及应用于3xTg-AD小鼠脑提取物的相同方法的发现形成对比。突触毒性物质的性质尚未确定。总体而言，我们的数据表明，在人类AD脑匀浆中存在一种或多种潜在的Aβ和tau非依赖性突触毒性活性。这一结果与突触丢失在早期认知功能下降中的关键作用一致，并可能为AD病理生理学提供新的见解。
Alzheimer’s disease (AD) is tightly correlated with synapse loss in vulnerable brain regions. It is assumed that specific molecular entities such as Aβ and tau cause synapse loss in AD, yet unbiased screens for synaptotoxic activities have not been performed. Here, we performed size exclusion chromatography on soluble human brain homogenates from AD cases, high pathology non-demented controls, and low pathology age-matched controls using our novel high content primary cultured neuron-based screening assay. Both presynaptic and postsynaptic toxicities were elevated in homogenates from AD cases and high pathology non-demented controls to a similar extent, with more modest synaptotoxic activities in homogenates from low pathology normal controls. Surprisingly, synaptotoxic activities were found in size fractions peaking between the 17–44 kDa size standards that did not match well with Aβ and tau immunoreactive species in these homogenates. The fractions containing previously identified high molecular weight soluble amyloid beta aggregates/”oligomers” were non-toxic in this assay. Furthermore, immunodepletion of Aβ and tau did not reduce synaptotoxic activity. This result contrasts with previous findings involving the same methods applied to 3xTg-AD mouse brain extracts. The nature of the synaptotoxic species has not been identified. Overall, our data indicates one or more potential Aβ and tau independent synaptotoxic activities in human AD brain homogenates. This result aligns well with the key role of synaptic loss in the early cognitive decline and may provide new insight into AD pathophysiology.