Quantitative spatial analysis of the mouse brain lipidome by pressurized liquid extraction surface analysis

Area of Science:

• Lipidomics
• Mass Spectrometry
• Tissue Analysis

Background:

• Lipidomics is crucial for understanding cellular functions and diseases.
• Existing methods for tissue lipid analysis often involve destructive sampling or lack spatial resolution.

Purpose of the Study:

• To introduce and validate a novel surface sampling technique, pressurized liquid extraction surface analysis (PLESA).
• To enable high-resolution, in situ quantification and structural characterization of molecular lipid species directly from tissue sections.

Main Methods:

• Pressurized liquid extraction surface analysis (PLESA) utilizing a sealed, pressurized probe for microextraction with 400 μm spatial resolution.
• Integration with a high-resolution shotgun lipidomics routine employing nanoelectrospray ionization and a hybrid ion trap-orbitrap mass spectrometer.
• Employing successive polarity shifting, high-resolution Fourier transform mass spectrometry (FTMS), and fragmentation analysis for lipid identification and quantification using internal standards.

Main Results:

• Demonstrated efficient in situ lipid microextraction using chloroform-containing solvents.
• Successfully quantified and structurally characterized 170 molecular lipid species across different mouse brain regions.
• Validated PLESA performance by comparing it with conventional lipid extraction methods from excised tissue homogenates.

Conclusions:

• PLESA offers a powerful tool for spatial lipidomics, enabling detailed molecular analysis directly from tissue surfaces.
• The technique facilitates mapping of lipid distribution and abundance, advancing our understanding of tissue-specific lipid profiles.
• PLESA provides a significant advancement over conventional methods for comprehensive lipidome analysis.