Organ-Derived Spectral Libraries Improve Sensitivity in DIA Plasma Peptidomics

Area of Science:

• Biochemistry
• Proteomics
• Systems Biology

Background:

• Plasma peptides are vital for homeostasis and disease regulation.
• High-abundance proteins like albumin complicate the analysis of organ-secreted peptides in plasma.
• Existing methods face challenges in comprehensively identifying native organ-derived peptides.

Purpose of the Study:

• To develop a highly sensitive plasma peptidomic approach for analyzing organ-derived peptides.
• To combine data-independent acquisition (DIA) with organ and plasma spectral libraries.
• To enable quantitative analysis and organ-of-origin assignment for plasma peptides.

Main Methods:

• Peptide extraction from plasma and eleven organ types using the differential solubilization method.
• Construction of an empirical spectral library via data-dependent acquisition (DDA) on a timsTOF HT.
• Analysis of DIA-MS data from plasma samples utilizing the established spectral library.

Main Results:

• Identification of over 5500 peptides per run on average.
• Detection of over 2000 organ-derived peptides, including 19 known bioactive peptides.
• Successful linkage of identified peptides to their secreting organs.

Conclusions:

• The novel DIA-MS strategy enables highly sensitive quantification of organ-derived peptides in plasma.
• This approach facilitates the discovery of novel biomarkers and bioactive peptides.
• The method is expected to advance the understanding of systemic disease pathophysiology.