A peptidomics strategy for discovering endogenous bioactive peptides.

Area of Science:

• Biochemistry
• Neuroscience
• Molecular Biology

Background:

• Naturally occurring peptides, including peptide hormones and neuropeptides, are crucial signaling molecules derived from precursor proteins.
• Identifying novel bioactive peptides from large datasets generated by tandem mass spectrometry remains a significant challenge in peptidomics.
• Understanding peptide function requires pinpointing their biological activity and target tissues.

Purpose of the Study:

• To develop and validate a novel approach for simultaneously screening bioactive peptides and their target tissues.
• To identify intact secretory peptides capable of modulating intracellular calcium levels.
• To discover novel bioactive neuropeptides and their associated physiological effects.

Main Methods:

• Utilized nanoflow liquid chromatography-tandem mass spectrometry (nLC-MS/MS) to analyze peptides secreted via exocytosis from cultured cells.
• Employed computational analysis to deduce intact peptide sequences from mass spectrometry data.
• Developed an ex vivo calcium assay using transgenic mice expressing the calcium indicator apoaequorin to test peptide bioactivity on tissue samples.

Main Results:

• Successfully identified intact secretory peptides with the ability to elicit intracellular calcium level changes.
• Identified novel bioactive neuropeptides derived from the neurosecretory protein VGF.
• Demonstrated that these novel VGF-derived neuropeptides induce a calcium response in pituitary and hypothalamic tissues.

Conclusions:

• The developed approach enables the simultaneous screening of bioactive peptides and their target tissues.
• This method is applicable to various cell types, including those difficult to culture in vitro.
• The discovery of novel VGF-derived neuropeptides highlights the potential of this approach for advancing neuropeptide research.