The phosphorylation of Hsp20 enhances its association with amyloid-β to increase protection against neuronal cell death.
The phosphorylation of Hsp20 enhances its association with amyloid-β to increase protection against neuronal cell death.
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DOI：
10.1016/j.mcn.2014.05.002
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发表时间：
2014-07
期刊：
影响因子：
--
通讯作者：
Baillie GS
中科院分区：
文献类型：
--
作者：
Cameron RT;Quinn SD;Cairns LS;MacLeod R;Samuel ID;Smith BO;Carlos Penedo J;Baillie GS
Hsp 20蛋白水平响应于淀粉样原纤维形成的上调被认为是对抗阿尔茨海默病（AD）发作的关键保护性应答。事实上，已知Hsp 20和Aβ之间的物理相互作用可防止Aβ寡聚化并保护神经元细胞免受Aβ介导的毒性，然而，该过程背后的分子机制和调节细胞信号传导事件的细节仍然难以捉摸。采用传统的MTT终点试验和新的真实的时间细胞阻抗测量，我们表明Hsp 20保护人神经母细胞瘤SH-SY 5 Y细胞免受Aβ的神经毒性作用。为了提供Hsp 20提供神经保护的机制，我们使用肽阵列、免疫共沉淀分析和NMR技术来绘制Hsp 20和Aβ之间的相互作用，并报告Hsp 20与Aβ寡聚化结构域相邻结合的结合模式，从而防止聚集。Hsp 20/Aβ相互作用通过Hsp 20磷酸化增强，其用于增加与低分子量Aβ物质的结合并降低破坏淀粉样蛋白寡聚体形成所需的Hsp 20的有效浓度。最后，使用一种新的荧光检测方法对形态特异性Aβ聚集进行真实的时间评价，我们发现这种效应的磷酸依赖性对于原纤维比对于球状Aβ形式更明显，并且对应于Hsp 20 N-末端的25聚体可以用作Aβ聚集体抑制剂。我们的报告首次为Hsp 20/Aβ复合物提供了分子模型，并首次提出cAMP/cGMP通路的调节可能是增强Hsp 20介导的Aβ纤维神经毒性衰减的新途径。
Up-regulation of Hsp20 protein levels in response to amyloid fibril formation is considered a key protective response against the onset of Alzheimer's disease (AD). Indeed, the physical interaction between Hsp20 and Aβ is known to prevent Aβ oligomerisation and protects neuronal cells from Aβ mediated toxicity, however, details of the molecular mechanism and regulatory cell signalling events behind this process have remained elusive. Using both conventional MTT end-point assays and novel real time measurement of cell impedance, we show that Hsp20 protects human neuroblastoma SH-SY5Y cells from the neurotoxic effects of Aβ. In an attempt to provide a mechanism for the neuroprotection afforded by Hsp20, we used peptide array, co-immunoprecipitation analysis and NMR techniques to map the interaction between Hsp20 and Aβ and report a binding mode where Hsp20 binds adjacent to the oligomerisation domain of Aβ, preventing aggregation. The Hsp20/Aβ interaction is enhanced by Hsp20 phosphorylation, which serves to increase association with low molecular weight Aβ species and decrease the effective concentration of Hsp20 required to disrupt the formation of amyloid oligomers. Finally, using a novel fluorescent assay for the real time evaluation of morphology-specific Aβ aggregation, we show that phospho-dependency of this effect is more pronounced for fibrils than for globular Aβ forms and that 25mers corresponding to the Hsp20 N-terminal can be used as Aβ aggregate inhibitors. Our report is the first to provide a molecular model for the Hsp20/Aβ complex and the first to suggest that modulation of the cAMP/cGMP pathways could be a novel route to enhance Hsp20-mediated attenuation of Aβ fibril neurotoxicity.
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影响因子：
5
作者：
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通讯作者：
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作者：
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Lobner, D
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通讯作者：
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