Label-free quantification LC-mass spectrometry proteomic analysis of blood plasma in healthy dogs

Abstract

Bloodwork is a widely used diagnostic tool in veterinary medicine, as diagnosis and therapeutic 15 interventions often rely on blood biomarkers. However, biomarkers available in veterinary medicine 16 often lack sensitivity or specificity. Mass spectrometry (MS)-based proteomics technology has been 17 extensively used in biological fluids and offers excellent potential for a more comprehensive 18 characterization of the plasma proteome in veterinary medicine. In this study, we aimed to identify 19 and quantify plasma proteins in a cohort of healthy dogs and compare two techniques for depleting 20 high-abundance plasma proteins to enable the detection of lower-abundance proteins. We utilized 21 surplus lithium-heparin plasma from 30 healthy dogs, which were subdivided into five groups of 22 pooled plasma from 6 randomly selected individuals each. Our goal was to identify and quantify 23 plasma proteins via label-free quantification LC-mass spectrometry. Additionally, we employed 24 different methods to deplete the most abundant proteins. Firstly, we used a commercial kit for the 25 depletion of high-abundance plasma proteins. Secondly, we employed an in-house method to 26 remove albumin using Blue-Sepharose. Among all the samples, some of the most abundant proteins 27 identified were apolipoprotein A and B, albumin, alpha-2-macroglobulin, fibrinogen beta chain, fibronectin, complement C3, serotransferrin, and coagulation Factor V.