GLYCOSYLTRANSFERASE ACTIVITIES IN CULTURED ENDOTHELIAL-CELLS OF BOVINE BRAIN MICROVASCULAR ORIGIN

Bovine brain microvascular endothelial cells (BMECs) express GM3 (NeuA c) and GM3 (NeuGc) as the major gangliosides, and GM1, GD1a, GD1b, GT1 b as well as sialosylparagloboside and sialosyllactosaminylparaglobosi de as the minor species. To investigate the metabolic basis of this ga nglioside pattern, the activities of eight glycosyltransferases (GM3-, GD1a-, GD3-, LM1-, GM2 (NeuAc)-, GM2 (NeuGc)-, LacCer-, and GM1-synth ases) in cultured BMECs were studied. It was found that BMECs possesse d high activities of GM3- and GD1a-synthases, and low activities of GM 2-, GM1-, and GD3-synthases. Thus, the present study provides evidence that endothelial cells are capable of synthesizing gangliosides in si tu and that the high content of GM3 in BMEC is closely associated with high activities of GM3-synthase and low activities of GM2-, GM1-, and GD3-synthases.