High-resolution spatiometabolomics in Drosophila: Advancing tissue-specific metabolomics via DESI-Mass Spectrometry Imaging

Understanding the complex metabolic networks governing development, behavior, and disease in the model organism like Drosophila requires high resolution, tissue specific insights. Traditional metabolomics techniques, such as LC-MS and GC-MS, offer robust quantification but necessitate tissue homogenization destroying crucial spatial architecture and limits to resolve metabolic crosstalk between distinct cell types. Here, we present an optimized Desorption Electrospray Ionization Mass Spectrometry Imaging (DESI-MSI) workflow tailored for the ambient mapping of metabolites and pharmaceuticals across diverse Drosophila tissues. Our protocol demonstrates the simultaneous mapping of metabolites including neurotransmitters, lipids, and central energy pathways at near cellular resolution as well as preserves the native biochemical state of fragile insect tissues while operating under ambient conditions. Here, we discuss the utility of DESI-MSI in resolving distinct metabolic microenvironments within intact tissues, mapping metabolic shifts that are otherwise obscured in bulk tissue lysates. Also, successfully delineating distinct metabolic microenvironments between neuronal and glial compartments within the Drosophila brain sections. Furthermore, we tested our method to a translational pharmacology workflow, tracking the blood-brain barrier penetration and spatial distribution of an exogenous drug treatment, while simultaneously monitoring its localized metabolic rescue effects using dfmr1 mutant flies significantly streamlining the tracking of both small molecule drugs and endogenous metabolites. Ultimately, this methodology establishes DESI-MSI as a spatially resolved toolkit for Drosophila research, unlocking new dimensions in functional genomics, toxicology, metabolic disease modeling, cellular metabolism, neurobiology, and preclinical drug discovery.