Mesoscale Metabolic Channeling Revealed by Multimodal Microscopy

Area of Science:

• Cellular Metabolism and Homeostasis
• Advanced Microscopy Techniques
• Systems Biology

Background:

• Cellular and tissue metabolism is crucial for energy generation and homeostasis.
• Current understanding relies on bulk analysis, lacking single-cell spatial resolution.
• Spatial nutrient utilization patterns within tissues remain largely uncharacterized.

Purpose of the Study:

• To develop and apply a novel high-resolution microscopy technique for mapping nutrient metabolism at the subcellular level.
• To quantitatively analyze the spatial distribution of nutrient flux within single cells and their organelles.
• To investigate organelle interactions and their role in metabolic channeling.

Main Methods:

• Pioneered high-resolution Multiplexed Ion Beam Imaging-Electron Microscopy (MIMS-EM) to track ¹³C-labeled nutrient atoms.
• Combined MIMS-EM with machine-learning image segmentation for quantitative analysis of glucose flux in hepatocytes.
• Employed network analysis to map organelle-organelle contact networks and metabolic enrichment.

Main Results:

• Established the cellular and organellar spatial patterns of glucose ¹³C flux in hepatocytes in situ.
• Identified distinct subpopulations of mitochondria and lipid droplets with unique organelle interactions and metabolic profiles.
• Discovered a novel association between lipid droplet proximity and the initiation of glycogenesis.

Conclusions:

• MIMS-EM is a powerful new tool for quantifying subcellular nutrient metabolism and spatial metabolic channeling.
• Revealed the importance of organelle-organelle interactions in directing nutrient flux.
• Provides a foundation for understanding metabolic heterogeneity and spatial regulation in complex tissues.