Building Multidimensional Biomarker Views of Type 2 Diabetes on the Basis of Protein Microheterogeneity

Abstract

BACKGROUND In 2008, the US Food and Drug Administration (FDA) issued a Guidance for Industry statement formally recognizing (during drug development) the conjoined nature of type 2 diabetes (T2D) and cardiovascular disease (CVD), which has precipitated an urgent need for panels of markers (and means of analysis) that are able to differentiate subtypes of CVD in the context of T2D. Here, we explore the possibility of creating such panels using the working hypothesis that proteins, in addition to carrying time-cumulative marks of hyperglycemia (e.g., protein glycation in the form of Hb A1c), may carry analogous information with regard to systemic oxidative stress and aberrant enzymatic signaling related to underlying pathobiologies involved in T2D and/or CVD. METHODS We used mass spectrometric immunoassay to quantify, in targeted fashion, relative differences in the glycation, oxidation, and truncation of 11 specific proteins. RESULTS Protein oxidation and truncation (owing to modified enzymatic activity) are able to distinguish between subsets of diabetic patients with or without a history of myocardial infarction and/or congestive heart failure where markers of glycation alone cannot. CONCLUSION Markers based on protein modifications aligned with the known pathobiologies of T2D represent a reservoir of potential cardiovascular markers that are needed to develop the next generation of antidiabetes medications.

Mass Spectrometric Immunoassays in Characterization of Clinically Significant Proteoforms

“…Since 1995, our group has published extensively on MSIA including core technology conception and development [47], assay development for dozens of human proteins [85,86,87,88], novel data modeling approaches [89], and also demonstrated ultra-high throughput application for >1000 samples per day intended for clinical use [52]. Listed in Table 1 are mass spectrometric immunoassays for human proteins expressing various proteoforms.…”

Top-down proteomics: applications, recent developments and perspectives

“…Therefore, there is a signif- icant interest in understanding the mechanisms contributing to the development of this condition [154]. Borges et al using a top-down proteomics approach identified a panel of PTM-based biomarkers to distinguish the spectrum of cardio vascular disease (CVD) and T2D co-morbidities [155].…”

Multiplexed Surrogate Analysis of Glycotransferase Activity in Whole Biospecimens

“…Top row: a) pre-purified Human Serum Amyloid P (contains only one complex-type N-linked glycan 46–47 ), b) pre-purified Bovine Ribonuclease B (RNase B, contains only one high mannose N-linked glycan 48–49 ). Bottom row: c) pre-purified Human Vitamin D Binding Protein (DBP, contains a NeuNAc2-3Gal1-3GalNAc O-linked glycan and no N-linked glycans 50–51 ) d) Pre-purified neutral glycosphingolipids from human granulocytes (largely characterized by their lactose (Gal1-4Glc)-base, 3-Gal and 4-GlcNAc-containing structures). Extracted ion chromatograms and symbol legend in this Figure are the same as in Fig.…”