The N-glycan profile of placental membrane glycoproteins alters during gestation and aging

Abstract

Alterations in the glycosylation of few membrane proteins from human placenta during gestation have been documented, but data on N-glycome of placental membrane proteins are still missing. The primary goal of this study was to obtain N-glycan profiles of human placental membrane proteins using a reliable, simple and high-throughput method. The second goal was to examine whether the N-glycan profile alters during gestation. Placental membrane proteins were isolated from women of different ages after first and third trimesters of pregnancy. The N-glycan fingerprint of membrane proteins was obtained using DNA sequencer-assisted fluorophore-assisted carbohydrate electrophoresis (DSA-FACE). Lectin blotting was used to confirm DSA-FACE results. Observed gestation-related alterations were: greater abundance of core-fucosylated and multiantennary N-glycans, but lower amounts of bisected biantennary N-glycans together with a decrease in α2,3-sialylation. Age-related alterations were: more core Fuc and more α2,3-Sia in first trimester placentas from older women than in those from younger women; also less core Fuc and less α2,6-Sia in third trimester placentas from older women compared to those from younger women. This study represents the first N-glycan profiling of placental cell membrane proteins. These data represent a basis for future research on the N-glycome of placental proteins in different (patho)physiological conditions.