Ganglioside and related-sphingolipid profiles are altered in a cellular model of Alzheimer's disease

Sphingolipid-related issues are increasingly discussed to contribute to the neuropathological process of Alzheimer's disease (AD). In this study, gangliosides and related-sphingolipids (ceramides, neutral glycosphingolipids and sphingomyelins) were analyzed in neuroglioma (H4) cells expressing the Swedish mutation of the human amyloid precursor protein (H4APPsw) and compared with those of wild-type control H4 cells. These cells were chosen since H4APPsw cells were previously reported to reproduce well some essential features of AD. We found that H4APPsw cells exhibited a striking elevation of the simplest ganglioside GM3, an abnormality that was consistently reported in AD patients and animal models of AD. Concomitantly, the levels of both lactosylceramide (the immediate metabolic precursor of GM3) and ganglioside GD1a increased, suggesting a deregulation in the biosynthesis of gangliosides in the H4APPsw cells. Moreover, while the total ceramide level remained unaltered in H4APPsw cells, a shift in ceramide composition from long chain - to very long chain fatty acid-ceramide species was recorded. Because sphingolipid alterations occurring in H4APPsw cells were similar to those observed in transgenic mice and in human brains, this cellular model might be useful to further explore the complex role of sphingolipids in AD pathogenesis.