Nanoproteomics enables proteoform-resolved analysis of low-abundance proteins in human serum

ABSTRACT: Top-down mass spectrometry (MS)-based proteomics provides a comprehensive analysis of proteoforms to achieve a proteome-wide understanding of protein functions. However, the MS detection of low-abundance proteins from the blood remains an unsolved challenge due to the complexity and extraordinary dynamic range of the blood proteome. Here we develop an integrated ‘nanoproteomics’ method coupling peptide-functionalized superparamagnetic nanoparticles (NPs) with top-down MS for the enrichment and comprehensive analysis of low-abundance cardiac troponin I (cTnI), a gold-standard biomarker for cardiovascular diseases, directly from human serum. These NPs allow for the sensitive enrichment of cTnI (< 1 ng/mL) with high specificity and reproducibility, while simultaneously depleting highly abundant blood proteins such as human serum albumin (>10 orders of magnitude more abundant than cTnI). We demonstrate for the first time that top-down nanoproteomics can provide high-resolution proteoform-resolved molecular fingerprints of diverse cTnI proteoforms to establish proteoform-pathophysiology relationships. This scalable and reproducible antibody-free strategy can generally enable the proteoform-resolved analysis of low-abundance proteins directly from serum to reveal previously unachievable molecular details.

INSTRUMENT(S): maXis

ORGANISM(S): Homo Sapiens (human)

TISSUE(S): Heart, Blood Serum

SUBMITTER: David Roberts  

LAB HEAD: Ying Ge

PROVIDER: PXD019712 | Pride | 2020-09-11

REPOSITORIES: Pride