Multimodal mass spectrometry imaging for plaque- and region-specific neurolipidomics in Alzheimer's disease mouse models.

The progressive accumulation of amyloid beta (Aβ) plaques is a hallmark of Alzheimer's disease (AD). However, the biochemical mechanisms of their formation and the consequences associated with plaque formation remain elusive. In female 5xFAD and APPNL-G-F mice, we map region-specific, plaque-associated lipids with large molecular coverage including isomers. We describe a multimodal framework that integrates matrix assisted laser desorption/ionization with laser-induced postionization (MALDI-2) mass spectrometry imaging, trapped ion mobility spectrometry, and fluorescence microscopy. Our approach improves detectability and spatial-chemical resolution. We couple these measurements with a computational pipeline for multimodal image coregistration and discovery of plaque-altered lipids. Here, we show the lipids in and around Aβ plaques are highly heterogeneous. Integration of our data with existing spatial transcriptomics data suggests that region-specific accumulation of simple gangliosides is likely driven by lysosomal degradation of complex species. Together, this work provides a generalizable framework to understand lipid alterations within the Aβ plaque microenvironment.