Gangliosides Are Important for the Preservation of the Structure and Organization of RBL-2H3 Mast Cells

Abstract

S U M M A R Y Gangliosides are known to be important in many biological processes. However, details concerning the exact function of these glycosphingolipids in cell physiology are poorly understood. In this study, the role of gangliosides present on the surface of rodent mast cells in maintaining cell structure was examined using RBL-2H3 mast cells and two mutant cell lines (E5 and D1) deficient in the gangliosides, GM 1 and the a-galactosyl derivatives of the ganglioside GD 1b . The two deficient cell lines were morphologically different from each other as well as from the parental RBL-2H3 cells. Actin filaments in RBL-2H3 and E5 cells were under the plasma membrane following the spindle shape of the cells, whereas in D1 cells, they were concentrated in large membrane ruffles. Microtubules in RBL-2H3 and E5 cells radiated from the centrosome and were organized into long, straight bundles. The bundles in D1 cells were thicker and organized circumferentially under the plasma membrane. The endoplasmic reticulum, the Golgi complex, and the secretory granule matrix were also altered in the mutant cell lines. These results suggest that the mast cellspecific a-galactosyl derivatives of ganglioside GD 1b and GM 1 are important in maintaining normal cell morphology. (J Histochem Cytochem 58:83-93, 2010)

Lipid Rafts in Mast Cell Biology

“…According to Kato et al [ 88 ], the lipid composition could influence membrane stability, membrane fluidity, lipid packing, bilayer curvature, and hydration elasticity, as well as anchorage of the cytoskeleton to the plasma membrane. Silveira e Souza et al [ 79 ] also observed that the D1 cells showed an abnormal distribution of actin filaments and microtubules. A growing body of evidence indicates that lipid rafts are essential for membrane-cytoskeleton coupling, and the association of Lyn and other raft markers with crosslinked Fc ε RI is regulated by interactions with F-actin [ 89 – 91 ].…”

“…The influence of gangliosides and/or lipid rafts on cell structure and organization was examined [ 79 ] using a ganglioside-deficient cell line, D1, and the parent cell line, RBL-2H3, a cell line with homology to mucosal mast cells [ 80 – 84 ]. The D1 cell line is deficient in GM 1 gangliosides and in mast cell specific α -galactosyl derivatives of the ganglioside GD 1b .…”

n-3 Polyunsaturated fatty acids and mast cell activation

“…Some of the lipid raft components appear to be important in maintaining mast cell morphology and mast cell development. After depletion of ganglioside (a raft component), RBL-2H3 cells change from a spindle to a round shape and are smaller [171]. As membrane domains, compelling evidence has shown that lipid rafts are involved in Fc«RI endocytosis and Fc«RI-mediated signal transduction in mast cells.…”

GD1b-Derived Gangliosides Modulate FcεRI Endocytosis in Mast Cells

“…The E5 and D1 cell lines express 35% and <1%, respectively, of the α-galactosyl derivatives of ganglioside GD1b when compared to RBL-2H3 cells (Silveira e Souza et al 2008). The E5 cells express 82.9% and D1 cells express <1% of GM1 in relation to the amount in RBL-2H3 cells (Silveira e Souza et al 2010). All cell lines used in these experiments were grown as monolayers, as previously described (Barsumian et al 1981).…”