E-Poster Presentation ESA-SRB-ANZBMS 2021

Mass spectrometry tissue imaging identifies complex/hybrid-type N-glycans as putative novel cartilage degradation markers for human knee osteoarthritis (#710)

Yea Rin Olivia Lee 1 , Matthew Briggs 2 , Julia Kuliwaba 3 , Peter Hoffmann 2 , Dzenita Muratovic 3 , Paul Anderson 1
  1. Clinical and Health Sciences, Health and Biomedical Innovation, University of South Australia, Adelaide, SA, Australia
  2. Future Industries Institute, University of South Australia, Mawson Lakes, South Australia, Australia
  3. Discipline of Orthopaedics and Trauma, Adelaide Medical School, The University of Adelaide, Adelaide, South Australia, Australia

Objective:

Knee osteoarthritis (KOA) is the most common form of arthritis, but the biomolecular, especially post-translational modifications such as N-glycans, involvement of its onset and progression is controversial. Thus, the aim of this study was to spatially localise, identify, and compare N-glycans from formalin-fixed paraffin-embedded (FFPE) osteochondral tissue in KOA patients and cadaveric controls (CTL).

Methods:

FFPE osteochondral tissue from end-stage KOA patients (n=3) and CTL individuals (n=3), >55 years of age, were analysed by advanced matrix‐assisted laser desorption/ionisation mass spectrometry imaging (MALDI‐MSI). In-house developed gelatin pre-coating workflows were used to obtain the imaging data. Based on the theoretical masses, N-glycan peaks were then manually selected, and ion intensity maps were generated using FlexImaging and SCiLS Lab software. Putative N-glycan structures were annotated using the following tools: GlycoMod, which calculates the theoretical monosaccharide composition, and Glycoworkbench to create individual N-glycan structures.

Results:

MALDI-MSI revealed differential N-glycan profiles between KOA patients and CTL individuals within the cartilage region only. Overall, 26 N-glycans were found significantly elevated in KOA cartilage as compared to CTL cartilage, with approximately a 2.5-fold increase in the signal intensity. In addition, there were particular three complex/hybrid-type N-glycans of m/z 1298.4, 1501.5, and 1663.5 ± 0.5 Da found predominantly in the upper fibrillated surface of degraded cartilage (OARSI histological grade 2.5-3), with minimal signal intensity in the adjacent surface with less damaged cartilage (OARSI histological grade 1-1.5).

Conclusion:

Our preliminary results demonstrate the novel application of MALDI-MSI to identify and localise KOA cartilage‐specific N-glycans. The alterations of these particular complex/hybrid-type N-glycans could evolve into a potential cartilage degradation marker and a possible new target for future treatment of cartilage degradation in patients with KOA. Further validation of these results is currently in progress using a fragmentation technique called liquid chromatography/tandem mass spectrometry (LC-MS/MS).