Identification of urinary biomarkers for type 2 diabetes using bead-based proteomic approach

Abstract

Aims: To seek urinary peptides as biomarkers distinguishing type 2 diabetes mellitus (T2DM) patients from healthy controls.

Methods: Random urine samples obtained from 28 patients with T2DM and 29 healthy individuals were analyzed by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) after purification using weak cationic-exchange magnetic beads (MB-WCX). Then the generated mass spectra of peptides were analyzed by ClinProTools2.1 bioinformatics software. Subsequently, the amino acid sequences of differently expressed peptides were identified by a nano-liquid chromatography-tandem mass spectrometry and a Sequest search found the corresponding protein name.

Results: Three differently expressed peptides and their mass to charge ratios (m/z) were found. Compared with healthy controls, the peak areas of the three differently expressed peptides were all reduced in T2DM, and the m/z were 1056.1 (m/z), 1963.5 (m/z), 2123.5 (m/z), respectively. The above-mentioned peptides were further identified as fragments of histidine triad nucleotide-binding protein 1 (HINT1), bifunctional aminoacyl-tRNA synthetase (EPRS), and clusterin precursor protein (CLU).

Conclusions: Histidine triad nucleotide-binding protein 1, bifunctional aminoacyl-tRNA synthetase, and clusterin precursor protein may serve as potential biomarkers distinguishing type 2 diabetes mellitus patients from healthy controls.

Keywords: Biomarkers; CLU; Cp; DAPK; EPRS; FPG; GAIT; GAPDH; HINT1; HbA1C; IFN-γ activated inhibitor of translation; MALDI-TOF MS; MB-WCX; MSC; NS1-associated protein 1; NSAP1; ROS; T2DM; Type 2 diabetes mellitus; Urinary peptides; VEGF-A; bifunctional aminoacyl-tRNA synthetase; ceruloplasmin; clusterin precursor protein; death associated protein kinase; fasting plasma glucose; glycated hemoglobin; glyceraldehydes-3-phosphate dehydrogenase; histidine triad nucleotide-binding protein 1; m/z; mass to charge ratio; matrix-assisted laser desorption ionization time-of-flight mass spectrometry; multi-tRNA synthetase complex; reactive oxygen species; type 2 diabetes mellitus; vascular endothelial growth factor A; weak cationic-exchange magnetic beads.