Visualization of Phospholipid Synthesis on Tissue Sections Using Functional Mass Spectrometry Imaging

Area of Science:

• Biochemistry
• Molecular Biology
• Analytical Chemistry

Background:

• Phospholipids are essential cellular components with diverse molecular species.
• Their spatial distribution is cell-type specific and linked to function.
• Understanding phospholipid biosynthesis pathways is crucial for cell biology.

Purpose of the Study:

• To apply functional mass spectrometry imaging (fMSI) to map enzyme activities in phospholipid biosynthesis.
• To visualize the spatial distribution of key enzymes like GPAT, LPAAT, LPLAT, and ACSL.
• To investigate enzyme activity variations based on fatty acid substrates and sequential reactions.

Main Methods:

• Utilized functional mass spectrometry imaging (fMSI) for high-resolution spatial analysis.
• Employed deuterium- and 13C-labeled substrates to trace enzyme activity.
• Visualized activities of glycerol 3-phosphate acyltransferase (GPAT), lysophosphatidic acid acyltransferases (LPAAT), lysophospholipid acyltransferases (LPLAT), and long-chain acyl-CoA synthetase (ACSL).

Main Results:

• Successfully mapped the spatial distribution of key phospholipid synthesis enzymes in tissues.
• Visualized a two-step sequential enzyme reaction involving ACSL and LPLAT.
• Observed significant variations in enzyme activity distribution correlating with different fatty acid substrates.

Conclusions:

• fMSI is a powerful tool for dissecting complex enzyme activities in situ.
• The study provides novel insights into the spatial regulation of phospholipid biosynthesis.
• This approach facilitates understanding the formation mechanisms of diverse phospholipid species.