A Caffeic Acid Matrix Improves In Situ Detection and Imaging of Proteins with High Molecular Weight Close to 200,000 Da in Tissues by Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry Imaging
A Caffeic Acid Matrix Improves In Situ Detection and Imaging of Proteins with High Molecular Weight Close to 200,000 Da in Tissues by Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry Imaging
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咖啡酸基质通过基质辅助激光解吸/电离质谱成像改善组织中分子量接近 200,000 Da 的蛋白质的原位检测和成像。
DOI：
10.1021/acs.analchem.0c05480
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发表时间：
2021-08-18
影响因子：
7.4
通讯作者：
Wang，Xiaodong
中科院分区：
文献类型：
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作者：
Liu，Haiqiang;Han，Manman;Wang，Xiaodong
据我们所知，这是首次利用基质辅助激光解吸电离质谱仪(MALDI-MSI)成功地评价了咖啡酸(CA)作为基质来增强三种生物组织切片(即大鼠脑、辣椒和萌发的大豆种子)中内源蛋白质的原位检测和成像的研究。结果表明，CA具有较强的紫外吸收、近20万Da的超宽MS检测质量范围、微米级基质晶体、均匀的基质沉积和较高的电离效率。与两种常用的MALDI基质，即芥子酸(SA)和阿魏酸(FA)相比，使用CA可以在生物组织中清楚地检测到更多的高分子量(HMW)蛋白质离子信号(m/z>；30,000)。值得注意的是，与SA和FA相比，CA在从质量范围为m/z>；80000的生物组织中原位检测HMW蛋白质方面表现出优异的性能。此外，CA基质的使用还显著增强了选定生物组织切片表面的蛋白质成像。首次成功地从大鼠脑中获得了3个HMW蛋白质离子信号(m/z 50,419，m/z 65,874和m/z 191,872)，从马赛凯子中获得了2个甜蛋白(mabinlin-2和mabinlin-4)和从萌发中的大豆种子中获得了3个HMW蛋白质离子信号(m/z 94,838，m/z 134,204和m/z 198,738)。我们的研究证明CA有潜力成为MALDI-MSI增强动物和植物组织中HMW蛋白质组织成像的标准有机酸基质。
To our knowledge, this was the first study in which caffeic acid (CA) was successfully evaluated as a matrix to enhance the in situ detection and imaging of endogenous proteins in three biological tissue sections (i.e., a rat brain and Capparis masaikai and germinating soybean seeds) by matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI). Our results show several properties of CA, including strong ultraviolet absorption, a super-wide MS detection mass range close to 200,000 Da, micrometer-sized matrix crystals, uniform matrix deposition, and high ionization efficiency. More high-molecular-weight (HMW) protein ion signals (m/z > 30,000) could be clearly detected in biological tissues with the use of CA, compared to two commonly used MALDI matrices, i.e., sinapinic acid (SA) and ferulic acid (FA). Notably, CA shows excellent performance for HMW protein in situ detection from biological tissues in the mass range m/z > 80,000, compared to the use of SA and FA. Furthermore, the use of a CA matrix also significantly enhanced the imaging of proteins on the surface of selected biological tissue sections. Three HMW protein ion signals (m/z 50,419, m/z 65,874, and m/z 191,872) from a rat brain, two sweet proteins (mabinlin-2 and mabinlin-4) from a Capparis masaikai seed, and three HMW protein ion signals (m/z 94,838, m/z 134,204, and m/z 198,738) from a germinating soybean seed were successfully imaged for the first time. Our study proves that CA has the potential to become a standard organic acid matrix for enhanced tissue imaging of HMW proteins by MALDI-MSI in both animal and plant tissues.