Wang Jasmine S-H, Whitehead Shawn N, Yeung Ken K-C
Department of Chemistry, University of Western Ontario, London, ON, N6A 5B7, Canada.
Department of Biochemistry, University of Western Ontario, London, ON, N6A 5C1, Canada.
J Am Soc Mass Spectrom. 2018 Apr;29(4):786-795. doi: 10.1007/s13361-018-1896-z. Epub 2018 Feb 20.
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. Graphical Abstract ᅟ.
本文考察了将基质辅助激光解吸电离质谱（MALDI MS）作为一种快速直接检测不同质量Aβ寡聚体的方法。实验结果表明，Aβ寡聚体被电离并作为单电荷离子被检测到，因此，所得质谱直接反映了寡聚体的大小分布。进行了验证实验以验证质谱数据是否存在假象。比较了从具有不同聚集倾向的修饰Aβ肽收集的质谱。一般来说，预期寡聚化更有利的样品中多聚体的相对强度更高，反之亦然。MALDI MS还能够检测孵育/寡聚化步骤前后寡聚体组成的差异。样品组成的这种差异也通过对原代大鼠皮层神经元进行的体外Aβ毒性研究得到了独立证实。通过使用分子量截留滤器从样品中去除寡聚体完成了额外的验证；所得质谱数据正确反映了在预期截留点处的去除情况。这些结果共同验证了MALDI MS评估Aβ样品单体/多聚体组成的能力。图形摘要ᅟ 。
