In-Source Fragmentation Annotation in Sterol Mass Spectrometry Imaging

Area of Science:

• Spatial biology
• Molecular imaging
• Mass spectrometry imaging (MSI)

Background:

• MSI is crucial for molecular imaging in spatial biology.
• MALDI-2 technology enhances MSI sensitivity, particularly for neutral metabolites like sterols.
• Sterols are vital in physiological processes, including neurodegenerative diseases.

Purpose of the Study:

• Investigate in-source fragmentation (ISF) of cholesterol during MSI.
• Assess the impact of ISF on biological interpretation under MALDI and MALDI-2 conditions.
• Introduce a high-resolution MSI technique for precise cholesterol distribution analysis.

Main Methods:

• Utilized a murine intervention model.
• Performed MSI under both MALDI and MALDI-2 conditions.
• Employed high-resolution (5 μm) MSI for spatial analysis.

Main Results:

• Observed and investigated cholesterol ISF under MALDI and MALDI-2.
• Demonstrated that ISF can lead to significant misinterpretations in biological analysis.
• Showcased the utility of high-resolution MSI for precise cholesterol mapping.

Conclusions:

• ISF is a critical challenge in MSI, potentially compromising accurate molecular annotation.
• Addressing ISF, especially with MALDI-2, is essential for reliable biological insights.
• Tandem mass spectrometry is recommended for accurate annotation of in-source fragments.