Image-guided MALDI mass spectrometry for high-throughput single-organelle characterization

Area of Science:

• Cell Biology
• Biochemistry
• Neuroscience

Background:

• Dense-core vesicles are essential for packaging and releasing neuropeptides and peptide hormones, vital for brain, endocrine, and exocrine functions.
• Characterizing the chemical heterogeneity within these organelles is challenging due to their small size.

Purpose of the Study:

• To develop and apply image-guided, high-throughput mass spectrometry protocols for chemically profiling dense-core and lucent vesicles.
• To investigate the lipid and peptide content heterogeneity within and between these vesicle populations at the single-organelle level.

Main Methods:

• Image-guided, high-throughput mass spectrometry was employed to analyze large populations of dense-core and lucent vesicles.
• Lipid and peptide contents of individual organelles were profiled to assess chemical heterogeneity.

Main Results:

• Proteolytic processing products of four prohormones were identified within dense-core vesicles.
• Mass spectral features indicated the presence of at least three distinct dense-core vesicle populations.
• Significant differences in lipid mass profiles were observed between dense-core and lucent vesicles.

Conclusions:

• The study successfully characterized chemical heterogeneity within dense-core and lucent vesicles using novel mass spectrometry approaches.
• These methods reveal distinct subpopulations of dense-core vesicles based on their peptide content.
• The developed single-organelle mass spectrometry techniques are adaptable for profiling various subcellular structures.