Gangliosides attenuate ethanol-induced apoptosis in rat cerebellar granule neurons

Ethanol significantly enhances cell death of differentiated rat cerebellar granule neurons on culture in a serum-free medium containing a depolarizing concentration of KCl (25 mM), 5 microM MK-801 (an NMDA receptor antagonist), and 20-200 mM ethanol for 1-4 days. Cell death augmented by ethanol was concentration- and time-dependent with neurons displaying hallmark apoptotic morphology and DNA fragmentation that correlated with the activation of cytosolic caspase-3. Inclusion of 5 microM MK-801 or 100 microM glycine in culture media did not alter rates of cell death indicating ethanol toxicity is mediated via an NMDA receptor-independent pathway. Preincubation with 50 microM gangliosides GM1, GD1a, GD1b or GT1b for 2 h, or preincubation with 10 microM LIGA20 (a semisynthetic GM1 with N-dichloroacetylsphingosine) for 10 min, attenuated caspase-3 activity and ethanol-induced cell death. Data show native gangliosides and a synthetic derivative are potently neuroprotective in this model of ethanol toxicity, and potentially serve as useful probes to further unravel the mechanisms relevant to neuronal apoptosis.