Nascent proteomes in peripheral blood mononuclear cells as a novel source for biomarker discovery in human stroke.

BACKGROUND AND PURPOSE The proteome of newly synthesized proteins (nascent proteome) in peripheral blood mononuclear cells (PBMCs) can be a novel source of stroke biomarkers. Changes in the PBMC nascent proteome after stroke reflect the dynamic response-in-action not detectable in the total proteome (all existing proteins) in blood. Here, we test the application of nascent proteomics as a novel approach for stroke biomarker discovery. METHODS The PBMC nascent proteome in human blood was determined by metabolic labeling of fresh PBMC cultures with azidohomoalanine (an azide-containing methionine surrogate), followed by mass spectrometry detection and quantification of azidohomoalanine-labeled proteins. The PBMC nascent and total proteomes were compared between patients with stroke and matched controls. RESULTS Both PBMC nascent and total proteomes showed differences between stroke patients and controls. Results of hierarchical clustering analysis of proteomic data revealed greater changes in the nascent than in the total PBMC proteomes, supporting the usefulness of the PBMC nascent proteome as a novel source of stroke biomarkers. CONCLUSIONS Nascent proteomes in PBMC can be a novel source for biomarker discovery in human stroke.