Effects of exogenous gangliosides on intracellular Ca2+ mobilization and functional responses in human platelets

Gangliosides, highly expressed in the outer leaflet of plasmamembranes, mediate a variety of biological processes, includingcell-cell and cell-matrix interactions. We examined the effectsof exogenous gangliosides on intracellular Ca²⁺ mobilizationand functional responses in human platelets. Gangliosides (GM₃and GM₁) induced rapid and reversible elevation of intracellularCa²⁺ in fura2-loaded platelets in a concentration-dependentmanner. The Ca²⁺mobilizing effect of gangliosides was not mimickedby de-N-acetyl-GM₃, lactosylceramide, or free sialic acid, suggestingthat structural integrity as ganglioside is essential for thiseffect. GM₃ and GM₁ also induced platelet shape change by themselvesand elicited aggregation in combination with epinephrine. Ourobservations suggest the involvement of ganglioside-activatedplatelets in atherosclerosis, in view of the high observed gangliosidelevels in atherosclerotic lesions of human aorta. de-N-acetyl-GM₃ ganglioside GM₃ intracellular Ca²⁺ mobilization platelet activation