Gangliosides raise the intracellular Ca2+ level in different cell types

Area of Science:

• Neuroscience
• Cell Biology
• Biochemistry

Background:

• Gangliosides are complex glycosphingolipids found in cell membranes.
• Previous studies suggested gangliosides possess anti-inflammatory properties and inhibit arachidonic acid release.
• The precise mechanisms underlying ganglioside functions, particularly their interaction with cellular signaling pathways, remain incompletely understood.

Purpose of the Study:

• To investigate the effect of total gangliosides from bovine brain on intracellular calcium levels.
• To determine if gangliosides influence calcium flux across cell membranes.
• To explore the potential relationship between ganglioside-induced calcium changes and their known biological activities.

Main Methods:

• Assays were performed using suspensions of rat macrophages, rat and chicken neurons, human erythrocytes, and liposomes.
• Cells and liposomes were loaded with the fluorescent calcium indicator FURA 2.
• Intracellular calcium increments were measured in a temperature, time, and dose-dependent manner following ganglioside treatment.

Main Results:

• Total gangliosides induced intracellular calcium (Ca2+) increments in all tested cell types and liposomes.
• The observed effect was independent of the endogenous ganglioside composition of the cells.
• Calcium release from inner stores was not induced by gangliosides, and the effect on neurons was independent of their differentiation state.

Conclusions:

• Gangliosides directly induce intracellular calcium increments, suggesting a novel mechanism of action.
• These findings indicate that the anti-inflammatory and arachidonic acid release inhibition by gangliosides are not mediated by impaired calcium flux.
• The results suggest that ganglioside-induced subtoxic cytosolic calcium increments may contribute to their neurotrophic effects on undifferentiated neurons.