Abstract：
Synaptic strength depends strongly on the subsynaptic organisation of presynaptic transmitter release and postsynaptic receptor densities, and their alterations are expected to underlie pathologies. Although synaptic dysfunctions are common pathogenic traits of Alzheimer\'s disease (AD), it remains unknown whether synaptic protein nano-organisation is altered in AD. Here, we systematically characterised the alterations in the subsynaptic organisation in cellular and mouse models of AD.
We used immunostaining and super-resolution stochastic optical reconstruction microscopy imaging to quantitatively examine the synaptic protein nano-organisation in both Aβ1-42-treated neuronal cultures and cortical sections from a mouse model of AD, APP23 mice.
We found that Aβ1-42-treatment of cultured hippocampal neurons decreased the synaptic retention of postsynaptic scaffolds and receptors and disrupted their nanoscale alignment to presynaptic transmitter release sites. In cortical sections, we found that while GluA1 receptors in wild-type mice were organised in subsynaptic nanoclusters with high local densities, receptors in APP23 mice distributed more homogeneously within synapses. This reorganisation, together with the reduced overall receptor density, led to reduced glutamatergic synaptic transmission. Meanwhile, the transsynaptic alignment between presynaptic release-guiding RIM1/2 and postsynaptic scaffolding protein PSD-95 was reduced in APP23 mice. Importantly, these reorganisations were progressive with age and were more pronounced in synapses in close vicinity of Aβ plaques with dense cores.
Our study revealed a spatiotemporal-specific reorganisation of synaptic nanostructures in AD and identifies dense-core amyloid plaques as the major local inductor in APP23 mice.
We used immunostaining and super-resolution stochastic optical reconstruction microscopy imaging to quantitatively examine the synaptic protein nano-organisation in both Aβ1-42-treated neuronal cultures and cortical sections from a mouse model of AD, APP23 mice.
We found that Aβ1-42-treatment of cultured hippocampal neurons decreased the synaptic retention of postsynaptic scaffolds and receptors and disrupted their nanoscale alignment to presynaptic transmitter release sites. In cortical sections, we found that while GluA1 receptors in wild-type mice were organised in subsynaptic nanoclusters with high local densities, receptors in APP23 mice distributed more homogeneously within synapses. This reorganisation, together with the reduced overall receptor density, led to reduced glutamatergic synaptic transmission. Meanwhile, the transsynaptic alignment between presynaptic release-guiding RIM1/2 and postsynaptic scaffolding protein PSD-95 was reduced in APP23 mice. Importantly, these reorganisations were progressive with age and were more pronounced in synapses in close vicinity of Aβ plaques with dense cores.
Our study revealed a spatiotemporal-specific reorganisation of synaptic nanostructures in AD and identifies dense-core amyloid plaques as the major local inductor in APP23 mice.
摘要：
目的：突触强度强烈依赖于突触前递质释放和突触后受体密度的突触下组织，他们的改变被认为是病理的基础。虽然突触功能障碍是阿尔茨海默病（AD）的常见致病特征，目前尚不清楚突触蛋白纳米组织在AD中是否发生改变。这里,我们系统地描述了AD细胞和小鼠模型中突触下组织的变化。
方法：我们使用免疫染色和超分辨率随机光学重建显微镜（STORM）成像来定量检查Aβ1-42处理的神经元培养物中的突触蛋白纳米组织和AD小鼠模型的皮质切片，APP23小鼠。
结果：我们发现Aβ1-42处理培养的海马神经元降低了突触后支架和受体的突触保留，并破坏了它们与突触前递质释放位点的纳米级排列。在皮质切片中，我们发现，虽然野生型小鼠的GluA1受体组织在具有高局部密度的突触下纳米簇，APP23小鼠的受体在突触内分布更均匀。这次重组，随着整体受体密度的降低，导致谷氨酸能突触传递减少。同时,在APP23小鼠中,突触前释放引导RIM1/2和突触后支架蛋白PSD-95之间的跨突触排列减少.重要的是,这些重组随着年龄的增长而进展，并且在具有致密核的Aβ斑块附近的突触中更为明显。
结论：我们的研究揭示了AD中突触纳米结构的时空特异性重组，并确定了致密核心淀粉样蛋白斑块是APP23小鼠的主要局部诱导剂。
方法：我们使用免疫染色和超分辨率随机光学重建显微镜（STORM）成像来定量检查Aβ1-42处理的神经元培养物中的突触蛋白纳米组织和AD小鼠模型的皮质切片，APP23小鼠。
结果：我们发现Aβ1-42处理培养的海马神经元降低了突触后支架和受体的突触保留，并破坏了它们与突触前递质释放位点的纳米级排列。在皮质切片中，我们发现，虽然野生型小鼠的GluA1受体组织在具有高局部密度的突触下纳米簇，APP23小鼠的受体在突触内分布更均匀。这次重组，随着整体受体密度的降低，导致谷氨酸能突触传递减少。同时,在APP23小鼠中,突触前释放引导RIM1/2和突触后支架蛋白PSD-95之间的跨突触排列减少.重要的是,这些重组随着年龄的增长而进展，并且在具有致密核的Aβ斑块附近的突触中更为明显。
结论：我们的研究揭示了AD中突触纳米结构的时空特异性重组，并确定了致密核心淀粉样蛋白斑块是APP23小鼠的主要局部诱导剂。
