Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
University of Pittsburgh Brain Institute, Pittsburgh, PA, USA.
J Alzheimers Dis. 2022;88(1):177-190. doi: 10.3233/JAD-220030.
Recent studies suggest a strong association between neuronal DNA damage, elevated levels of amyloid-β (Aβ), and regions of the brain that degenerate in Alzheimer's disease (AD).
To investigate the nature of this association, we tested the hypothesis that extensive DNA damage leads to an increase in Aβ40 and Aβ42 generation.
We utilized an immortalized human neuronal progenitor cell line (NPCs), ReN VM GA2. NPCs or 20 day differentiated neurons were treated with hydrogen peroxide or etoposide and allowed to recover for designated times. Sandwich ELISA was used to assess secreted Aβ40 and Aβ42. Western blotting, immunostaining, and neutral comet assay were used to evaluate the DNA damage response and processes indicative of AD pathology.
We determined that global hydrogen peroxide damage results in increased cellular Aβ40 and Aβ42 secretion 24 h after treatment in ReN GA2 NPCs. Similarly, DNA double strand break (DSB)-specific etoposide damage leads to increased Aβ40 and Aβ42 secretion 2 h and 4 h after treatment in ReN GA2 NPCs. In contrast, etoposide damage does not increase Aβ40 and Aβ42 secretion in post-mitotic ReN GA2 neurons.
These findings provide evidence that in our model, DNA damage is associated with an increase in Aβ secretion in neuronal progenitors, which may contribute to the early stages of neuronal pathology in AD.
最近的研究表明，神经元 DNA 损伤、淀粉样蛋白-β（Aβ）水平升高与阿尔茨海默病（AD）大脑中退化的区域之间存在很强的关联。
为了研究这种关联的本质，我们检验了这样一个假设，即广泛的 DNA 损伤会导致 Aβ40 和 Aβ42 的生成增加。
我们利用永生的人神经祖细胞系（NPCs）ReN VM GA2 进行了测试。将 NPCs 或 20 天分化的神经元用过氧化氢或依托泊苷处理，并在指定时间内恢复。夹心 ELISA 用于评估分泌的 Aβ40 和 Aβ42。Western blot、免疫染色和中性彗星试验用于评估 DNA 损伤反应和 AD 病理过程的指示物。
我们确定，全球过氧化氢损伤导致 ReN GA2 NPCs 中 24 小时后细胞 Aβ40 和 Aβ42 的分泌增加。同样，DNA 双链断裂（DSB）特异性依托泊苷损伤导致 ReN GA2 NPCs 中 2 小时和 4 小时后 Aβ40 和 Aβ42 的分泌增加。相比之下，依托泊苷损伤不会增加有丝分裂后 ReN GA2 神经元中的 Aβ40 和 Aβ42 分泌。
这些发现提供了证据，表明在我们的模型中，DNA 损伤与神经元祖细胞中 Aβ 分泌的增加有关，这可能有助于 AD 中神经元病理的早期阶段。
