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

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.