A Novel Mass Spectrometry Platform for Multiplexed N-Glycoprotein Biomarker Discovery from Patient Biofluids by Antibody Panel Based N-Glycan Imaging

Anal Chem. 2019 Jul 2;91(13):8429-8435. doi: 10.1021/acs.analchem.9b01445. Epub 2019 Jun 20.

Abstract

A new platform for N-glycoprotein analysis from serum that combines matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI MSI) workflows with antibody slide arrays is described. Antibody panel based (APB) N-glycan imaging allows for the specific capture of N-glycoproteins by antibodies on glass slides and N-glycan analysis in a protein-specific and multiplexed manner. Development of this technique has focused on characterizing two abundant and well-studied human serum glycoproteins, alpha-1-antitrypsin and immunoglobulin G. Using purified standard solutions and 1 μL samples of human serum, both glycoproteins can be immunocaptured and followed by enzymatic release of N-glycans. N-Glycans are detected with a MALDI FT-ICR mass spectrometer in a concentration-dependent manner while maintaining specificity of capture. Importantly, the N-glycans detected via slide-based antibody capture were identical to that of direct analysis of the spotted standards. As a proof of concept, this workflow was applied to patient serum samples from individuals with liver cirrhosis to accurately detect a characteristic increase in an IgG N-glycan. This novel approach to protein-specific N-glycan analysis from an antibody panel can be further expanded to include any glycoprotein for which a validated antibody exists. Additionally, this platform can be adapted for analysis of any biofluid or biological sample that can be analyzed by antibody arrays.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Biomarkers / metabolism*
  • Case-Control Studies
  • Glycomics / methods*
  • Glycoproteins / chemistry
  • Glycoproteins / metabolism*
  • Glycosylation
  • Humans
  • Liver Cirrhosis / diagnosis*
  • Liver Cirrhosis / metabolism
  • Optical Imaging / methods*
  • Polysaccharides / chemistry
  • Polysaccharides / metabolism*
  • Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / methods*

Substances

  • Biomarkers
  • Glycoproteins
  • Polysaccharides