SYNTHESIS OF GANGLIOSIDES BY CULTURED OLIGODENDROCYTES

Gangliosides are enriched in the nervous system compared to other tissues. The synthesis of gangliosides by monolayer cultures of isolated lamb oligodendrocytes was investigated. Cells were labeled with [3H]galactose at preselected times and gangliosides isolated by phase partition, purified and identified by chromatography. Cultured oligodendrocytes showed selectivity in their synthesis of gangliosides, which was expressed in the type of ganglioside synthesized and in the change of incorporation over time in culture. For the first 10 days there was very little incorporation of [3H]galactose in gangliosides, but this was followed by a stimulation of uptake for GM3, GM1/GD3 and GD1 gangliosides, reaching a maximum after .apprx. 25-30 days in vitro. There was little incorporation into GM2 or trisialogangliosides throughout the life of the cultures. Since oligodendrocytes synthesize extensive membranes during this period, the de novo-synthesized gangliosides may be used for membranes.