An Interspecies Comparison of Placental Gangliosides.

Abstract

The major ganglioside compositions of placental tissues from several species (rat, sea lion, porpoise, cow and horse) were compared. The samples were extracted with chloroform/methanol/water and the glycosphingolipid fractions were isolated through sequential treatment by peracetylation with pyridine/acetic anhydride, Florisil column chromatography, and deacetylation with sodium hydroxide. Gangliosides were isolated using DEAE Sephadex A-25 column chromatography. Their structures were identified by silica-gel thin-layer chromatography (TLC) and TLC/immunostaining using eight monoclonal antibodies that specifically recognize GM3, GM2, GD3, GD1a and IV3NeuAc-nLc4Cer (SPG). The major ganglioside in each placenta was GM3, comprising 50-80% of the total gangliosides. GM3 containing N-acetylneuraminic acid (NeuAc) was the major placental ganglioside in the sea lion and horse, whereas GM3 containing N-glycolylneuraminic acid (NeuGc) was the major ganglioside in the porpoise. In rat and cow placentas, the expression levels of both types of GM3 were equal. GD3 was detected in all five species. SPG was detected in them all except the rat. TLC/immunostaining detected GM2 (NeuAc) in the sea lion and cow, and GD1a (NeuAc, NeuAc) in the sea lion. We previously reported that the major gangliosides present in the rat placenta were GM3 and GD3. Therefore, GM3 and GD3 was commonly expressed in the placenta of six animal species examined.