Mapping the Fine-Scale Metabolic Heterogeneity of the Honeybee Brain by Mass Spectrometry Imaging

Mapping the spatiotemporal heterogeneity of metabolites is the key to understanding the complex physiological changes in organisms.The honeybee serves as an outstanding model for neurobiology and aging research, yet constructing a spatial metabolome atlas of the honeybee brain remains a challenge due to its tiny and fragile nature. As such, we systematically optimized the sample preparation protocols for mass spectrometry imaging analysis of the honeybee brain. In brief, we use undissected brains and a system of gelatin embedding to maintain tissue integrity while profiling the region-specific distributions of metabolites across multiple brain regions. Our results revealed that metabolic profiles significantly differ between different brain regions, with functionally related brain regions exhibiting similar metabolic signatures. By employing this strategy, we compared the spatial metabolomes of the longer-lived queen bees and the shorter-lived worker bees, revealing their metabolic divergence of cardiolipin and other glycerophospholipids within the mushroom body and compound eyes. This study further the methodology for spatial metabolomics of model insect brain and highlights the heterogeneity and complexity of metabolic aging at the suborgan level.