The use of MALDI MS as a fast and direct method to detect the Aβ oligomers of different masses is examined in this paper. Experimental results suggest that Aβ oligomers are ionized and detected as singly charged ions, and thus, the resulting mass spectrum directly reports the oligomer size distribution. Validation experiments were performed to verify the MS data against artifacts. Mass spectra collected from modified Aβ peptides with different propensities for aggregation were compared. Generally, the relative intensities of multimers were higher from samples where oligomerization was expected to be more favorable, and vice versa. MALDI MS was also able to detect the differences in oligomeric composition before and after the incubation/oligomerization step. Such differences in sample composition were also independently confirmed with an in vitro Aβ toxicity study on primary rat cortical neurons. An additional validation was accomplished through removal of oligomers from the sample using molecular weight cutoff filters; the resulting MS data correctly reflected the removal at the expected cutoff points. The results collectively validated the ability of MALDI MS to assess the monomeric/multimeric composition of Aβ samples.

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本文研究了使用MALDI MS作为快速直接的方法来检测不同质量的Aβ低聚物。实验结果表明，Aβ低聚物被电离并检测为单电荷离子，因此，所得质谱图直接报告了低聚物的大小分布。进行验证实验以验证伪造品的MS数据。比较了从具有不同聚集倾向的修饰Aβ肽收集的质谱图。通常，从低聚预期更有利的样品中，多聚体的相对强度较高，反之亦然。MALDI MS还能够在孵育/寡聚化步骤之前和之后检测寡聚体组成的差异。样品成​​分的这种差异也通过对原代大鼠皮层神经元的体外Aβ毒性研究独立确认。通过使用分子量截留过滤器从样品中除去低聚物来完成另一项验证。所得的MS数据正确反映了预期截止点处的去除。结果共同证明了MALDI MS评估Aβ样品的单体/多聚体组成的能力。

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