LESA MS Imaging of Heat-Preserved and Frozen Tissue: Benefits of Multistep Static FAIMS
LESA MS Imaging of Heat-Preserved and Frozen Tissue: Benefits of Multistep Static FAIMS
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DOI：
10.1021/acs.analchem.8b02739
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发表时间：
2018-11-20
影响因子：
7.4
通讯作者：
Cooper, Helen J.
中科院分区：
文献类型：
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作者：
Griffiths, Rian L.;Simmonds, Anna L.;Cooper, Helen J.
我们之前已经证明了液体萃取表面分析（LESA）高场不对称波形离子迁移谱（FAIMS）质谱成像的蛋白质在大脑和肝脏的薄组织切片。在这里，我们提出了一种改进的方法，该方法在每个采样位置使用多个静态FAIMS参数，并且可以显著提高同时成像的蛋白质，脂质和药物的数量。该方法适用于对照和盒式给药大鼠肾脏的质谱成像。肾脏的质谱成像通常需要清洗去除多余的血红蛋白；然而，对于这种方法，这是不必要的。多步静态FAIMS质谱分析结果表明，在没有FAIMS的情况下，检测到的蛋白质数量增加了6到16倍，除了比单步静态FAIMS（选择最佳的总蛋白质离子传输）增加较少。多步静态FAIMS质谱法检测蛋白质的好处也显示在睾丸切片中。多步FAIMS检测到的蛋白质数量比单步FAIMS增加了2- 3倍，比单独使用LESA增加了2- 14倍。最后，到目前为止，组织中蛋白质的LESA质谱分析仅在新鲜冷冻样品上进行。在这项工作中，我们证明了热保存组织也适用于这些分析。组织的保温提高了肾和睾丸组织的LESA MS检测到的蛋白质数量（2- 4倍）。对于这两种组织类型，在热处理样品中检测到的大多数蛋白质随后在加入FAIMS后的冷冻样品中检测到。肾组织的LESA FAIMS MS检测到的蛋白质数量有所增加；对于睾丸组织，保温后检测到的总蛋白较少；然而，大约三分之一是热保存样品所特有的。
We have previously demonstrated liquid extraction surface analysis (LESA) high field asymmetric waveform ion mobility spectrometry (FAIMS) mass spectrometry imaging of proteins in thin tissue sections of brain and liver. Here, we present an improved approach that makes use of multiple static FAIMS parameters at each sampled location and allows a significant improvement in the number of proteins, lipids, and drugs that can be imaged simultaneously. The approach is applied to the mass spectrometry imaging of control and cassette-dosed rat kidneys. Mass spectrometry imaging of kidneys typically requires washing to remove excess hemoglobin; however, that is not necessary with this approach. Multistep static FAIMS mass spectrometry resulted in a 6- to 16-fold increase in the number of proteins detected in the absence of FAIMS, in addition to smaller increases over single step static FAIMS (chosen for optimum transmission of total protein ions). The benefits of multistep static FAIMS mass spectrometry for protein detection are also shown for sections of testes. The numbers of proteins detected following multistep FAIMS increased between 2- and 3-fold over single step FAIMS and between 2- and 14-fold over LESA alone. Finally, to date, LESA mass spectrometry of proteins in tissue has been undertaken solely on fresh frozen samples. In this work, we demonstrate that heat preserved tissues are also suitable for these analyses. Heat preservation of tissue improved the number of proteins detected by LESA MS for both kidney and testes tissue (by between 2- and 4-fold). For both tissue types, the majority of the proteins additionally detected in the heat-treated samples were subsequently detected in the frozen samples when FAIMS was incorporated. Improvements in the numbers of proteins detected were observed for LESA FAIMS MS for the kidney tissue; for testes tissue, fewer total proteins were detected following heat preservation; however, approximately one-third were unique to the heat-preserved samples.