Mass spectrometric analysis of the glycosphingolipid‐derived glycans from miniature pig endothelial cells and islets: identification of NeuGc epitope in pig islets

Abstract

Glycosphingolipid (GSL) is a major component of the plasma membrane in eukaryotic cells that is involved directly in a variety of immunological events via cell-to-cell or cell-to-protein interactions. In this study, qualitative and quantitative analyses of GSL-derived glycans on endothelial cells and islets from a miniature pig were performed and their glycosylation patterns were compared. A total of 60 and 47 sialylated and neutral GSL-derived glycans from the endothelial cells and islets, respectively, were characterized by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and collision-induced fragmentation using positive-ion electrospray ionization (ESI) ion-trap tandem mass spectrometry (MS/MS). In accordance with previous immunohistochemistry studies, the alpha-Gal-terminated GSL was not detected but NeuGc-terminated GSLs were newly detected from miniature pig islets. In addition, the neutral GSL-derived glycans were relatively quantified by derivatization with carboxymethyl trimethylammonium hydrazide (so called Girard's T reagent) and MALDI-TOF MS. The structural information of the GSL-derived glycans from pig endothelial cells and islets suggests that special attention should be paid to all types of glycoconjugates expressed on pig tissues or cells for successful clinical xenotransplantation.