Multimodal Fusion of Lipid MALDI IMS with a Transgenic Fluorophore

Matrix-Assisted Laser Desorption/Ionization (MALDI) Imaging Mass Spectrometry (IMS) allows simultaneous mapping of thousands of molecules distributed in tissues. However, unambiguous identification of specific types or functional states of cells and correlation of such features to molecular localization are key challenges in the field. We report here the development of advances based on identity marking using a genetically encoded fluorophore. The fluorescence emission (F_em) data were integrated with IMS outputs through multimodal image processing with advanced registration techniques and data-driven image fusion. In an unbiased analysis of spleens, this approach enabled identification of new lipid species previously not identified in germinal centers (GC), such as the enrichment of ether lipids. We propose that this use of genetic marking of microanatomical regions of interest can be paired with molecular information from IMS for any tissue, cell type, or activity state for which fluorescence is driven by a gene-tracking allele.