MALDI HiPLEX-IHC: multiomic and multimodal imaging of targeted intact proteins in tissues.
MALDI HiPLEX-IHC: multiomic and multimodal imaging of targeted intact proteins in tissues.
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DOI：
10.3389/fchem.2023.1182404
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发表时间：
2023
影响因子：
5.5
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中科院分区：
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基质辅助激光解吸/电离质谱成像（MALDI-MSI）是对组织中代谢产物、脂类和药物等未标记小分子的空间分布进行成像的最广泛的方法之一。最近的进展带来了许多改进，包括实现单细胞空间分辨率的能力，3d组织图像重建，以及精确识别不同的异构体和等压分子。然而，迄今为止，生物标本中高分子量完整蛋白的MALDI-MSI很难实现。传统的方法通常需要原位蛋白水解和肽质量指纹，具有低空间分辨率，并且通常只能以非靶向方式检测最丰富的蛋白质。此外，还需要基于msi的多组学和多模态工作流程，以便对来自同一组织的小分子和完整蛋白质进行成像。这种能力可以在器官、组织和细胞的正常和病理功能水平上提供对生物系统巨大复杂性的更全面的理解。最近推出的一种称为MALDI HiPLEX-IHC（简称MALDI- ihc）的自上而下空间成像方法为实现组织甚至单个细胞的高信息含量成像提供了基础。基于新型的光可切割质量标签与抗体探针相结合，基于maldi的高plex、多模态和多组工作流程已经开发出来，可以在同一组织样品上对小分子和完整蛋白质进行成像。双标记抗体探针使多模态质谱和荧光成像的目标完整的蛋白质。使用相同的光可切割质量标签的类似方法可以应用于凝集素和其他探针。我们在这里详细介绍了MALDI-IHC工作流程的几个例子，这些工作流程旨在实现低至5 μ m的空间分辨率下组织的高plex，多组和多模态成像。该方法与其他现有的高复杂性方法（如成像细胞术、MIBI-TOF、GeoMx和CODEX）进行了比较。最后，对MALDI-IHC的应用前景进行了展望。
Matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) is one of the most widely used methods for imaging the spatial distribution of unlabeled small molecules such as metabolites, lipids and drugs in tissues. Recent progress has enabled many improvements including the ability to achieve single cell spatial resolution, 3D-tissue image reconstruction, and the precise identification of different isomeric and isobaric molecules. However, MALDI-MSI of high molecular weight intact proteins in biospecimens has thus far been difficult to achieve. Conventional methods normally require in situ proteolysis and peptide mass fingerprinting, have low spatial resolution, and typically detect only the most highly abundant proteins in an untargeted manner. In addition, MSI-based multiomic and multimodal workflows are needed which can image both small molecules and intact proteins from the same tissue. Such a capability can provide a more comprehensive understanding of the vast complexity of biological systems at the organ, tissue, and cellular levels of both normal and pathological function. A recently introduced top-down spatial imaging approach known as MALDI HiPLEX-IHC (MALDI-IHC for short) provides a basis for achieving this high-information content imaging of tissues and even individual cells. Based on novel photocleavable mass-tags conjugated to antibody probes, high-plex, multimodal and multiomic MALDI-based workflows have been developed to image both small molecules and intact proteins on the same tissue sample. Dual-labeled antibody probes enable multimodal mass spectrometry and fluorescent imaging of targeted intact proteins. A similar approach using the same photocleavable mass-tags can be applied to lectin and other probes. We detail here several examples of MALDI-IHC workflows designed to enable high-plex, multiomic and multimodal imaging of tissues at a spatial resolution as low as 5 µm. This approach is compared to other existing high-plex methods such as imaging mass cytometry, MIBI-TOF, GeoMx and CODEX. Finally, future applications of MALDI-IHC are discussed.