Altered N-glycan profile of IgG-depleted serum proteins in Hashimoto's thyroiditis.

Abstract

BACKGROUND:

Hashimoto's thyroiditis (HT) is an autoimmune disease characterized by chronic inflammation of thyroid gland. Although HT is the most common cause of hypothyroidism, the pathogenesis of this disease is not fully understood. Glycosylation of serum proteins was examined in HT only to a limited extent. The study was designed to determine the glycosylation pattern of IgG-depleted sera from HT patients.

METHODS:

Serum N-glycans released by N-glycosidase F (PNGase F) digestion were analyzed by normal-phase high-performance liquid chromatography (NP-HPLC). N-glycan structures in each collected HPLC fraction were determined by liquid chromatography-mass spectrometry (LC-MS) and exoglycosidase digestion. Fucosylation and sialylation was also analyzed by lectin blotting.

RESULTS:

The results showed an increase of monosialylated tri-antennary structure (A3G3S1) and disialylated diantennary N-glycan with antennary fucose (FA2G2S2). Subsequently, we analyzed the serum N-glycan profile by lectin blotting using lectins specific for fucose and sialic acid. We found a significant decrease of Lens culinaris agglutinin (LCA) staining in HT samples, which resulted from the reduction of α1,6-linked core fucose in HT serum. We also observed an increase of Maackia amurensis II lectin (MAL-II) reaction in HT due to the elevated level of α2,3-sialylation in HT sera.

CONCLUSIONS:

The detected alterations of serum protein sialylation might be caused by chronic inflammation in HT. The obtained results complete our previous IgG N-glycosylation analysis in autoimmune thyroid patients and show that the altered N-glycosylation of serum proteins is characteristic for autoimmunity process in HT. General Significance Thyroid autoimmunity is accompanied by changes of serum protein sialylation.

• Authors: Marta Ząbczyńska, Paweł Link-Lenczowski, Mislav Novokmet, Tiphaine Martin, Renata Turek-Jabrocka, Małgorzata Trofimiuk-Müldner, Ewa Pocheć
• Journal: Biochimica et biophysica acta. General subjects (Biochim Biophys Acta Gen Subj) Vol. 1864 Issue 3 Pg. 129464 (03 2020) ISSN: 1872-8006 [Electronic] Netherlands
• PMID: 31669586 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2019 The Authors. Published by Elsevier B.V. All rights reserved.

Chemical References

• Immunoglobulin G
• Lectins
• Polysaccharides
• glycosylated IgG
• Fucose
• Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase
• N-Acetylneuraminic Acid

Topics

• Adult
• Chromatography, High Pressure Liquid (methods)
• Female
• Fucose (metabolism)
• Glycosylation
• Hashimoto Disease (blood, immunology, metabolism)
• Humans
• Immunoglobulin G (metabolism)
• Inflammation (metabolism)
• Lectins (metabolism)
• Mass Spectrometry (methods)
• Middle Aged
• N-Acetylneuraminic Acid (metabolism)
• Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase (metabolism)
• Poland
• Polysaccharides (analysis, blood)
• Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization (methods)
• Thyroid Gland (metabolism)
• Thyroiditis (metabolism)