Mass spectrometry-based analyses showing the effects of secretor and blood group status on salivary N-glycosylation.

Matthew E Albertolle,Steven C Hall,H Ewa Witkowska,Akraporn Prakobphol,Andrew B Dykstra,Susan J Fisher,Katherine Williams,Maria E Hassis,Richard K Niles,Severino Cuison,Connie Jen Ng

doi:10.1186/s12014-015-9100-y

Matthew E Albertolle, Steven C Hall + Show 9 more

Open Access

https://doi.org/10.1186/s12014-015-9100-y

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Journal: Clinical Proteomics	Publication Date: Dec 1, 2015
Citations: 71	License type: CC BY 4.0

Affiliation: University of California, San Francisco

Abstract

BackgroundThe carbohydrate portions of salivary glycoproteins play important roles, including mediating bacterial and leukocyte adhesion. Salivary glycosylation is complex. Many of its glycoproteins present ABO and Lewis blood group determinants. An individual’s genetic complement and secretor status govern the expression of blood group antigens. We queried the extent to which salivary glycosylation varies according to blood group and secretor status. First, we screened submandibular/sublingual and parotid salivas collected as ductal secretions for reactivity with a panel of 16 lectins. We selected three lectins that reacted with the largest number of glycoproteins and one that recognized uncommon lactosamine-containing structures. Ductal salivas representing a secretor with complex blood group expression and a nonsecretor with a simple pattern were separated by SDS-PAGE. Gel slices were trypsin digested and the glycopeptides were individually separated on each of the four lectins. The bound fractions were de-N-glycosylated. LC–MS/MS identified the original glycosylation sites, the peptide sequences, and the parent proteins.ResultsThe results revealed novel salivary N-glycosites and glycoproteins not previously reported. As compared to the secretor, nonsecretor saliva had higher levels of N-glycosylation albeit with simpler structures.ConclusionsTogether, the results suggested a molecular basis for inter-individual variations in salivary protein glycosylation with functional implications for oral health.Electronic supplementary materialThe online version of this article (doi:10.1186/s12014-015-9100-y) contains supplementary material, which is available to authorized users.

Highlights

The carbohydrate portions of salivary glycoproteins play important roles, including mediating bacterial and leukocyte adhesion
Lectin selection As a first step, we screened submandibular/ sublingual (SMSL) and parotid saliva samples collected as the ductal secretions from twenty individuals for reactivity with a 16-lectin panel (Additional file 1: Figure S1)
The donors were chosen as representing the spectrum of glycosylation commonly observed in the general US population with regard to the addition of carbohydrate blood group determinants to the core oligosaccharide structures of glycoproteins

Summary

Introduction

The carbohydrate portions of salivary glycoproteins play important roles, including mediating bacterial and leukocyte adhesion. We queried the extent to which salivary glycosylation varies according to blood group and secretor status. Ductal salivas representing a secretor with complex blood group expression and a nonsecretor with a simple pattern were separated by SDS-PAGE. Salivary components can be immobilized within the oral cavity, e.g, the pellicle that coats the tooth surface. In both phases, saliva plays many critical roles in general aspects of health (reviewed in [1, 2]). More than 3000 proteins/ peptides have been identified (reviewed in Amado et al [3]) with ductal saliva having about 400 major constituents [4].

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