title: Inhibitory effect of ganglioside on mastoparan-induced cytotoxicity and degranulation in lipid raft of connective tissue type mast cell.
abstract: Antihistamine, the most important drug for Hymenoptera stinging, cannot attenuate cytotoxicity and mast cell direct activation by mastoparan that is the most abundant polypeptides in the venoms of social wasps. The aim of this study was to investigate whether gangliosides inhibit the effect of mastoparan on mast cells activation. The degranulation and cytotoxicity in canine cutaneous mastocytoma cells (CM-MC) were done by measurement of β-hexosaminidase release and MTT assay. Lipid raft was isolated with discontinuous sucrose gradient centrifuge for the analysis of distribution of Gα(q) and Gα(i) protein by western blotting. We found that mastoparan induced the degranulation in (CM-MC) via direct activation of Gα(i) and Gα(q) with a decrease in their amount in lipid raft. Ganglioside G(D1a) (disialoganglioside) and G(M1) (monosialoganglioside) strongly reduced the degranulation and cytotoxicity through stabilizing the structure of lipid raft domain. In addition, mastoparan generated intracellular reactive oxygen species (ROS) independently from cytotoxicity, through arachidonic cascade but not G-protein activations. Crude wasp venom showed cytotoxicity and induction of the release from CM-MC, which were potently reduced by gangliosides. We show here that mastoparan activates both Gα(i) and Gα(q) protein and that the exogenous ganglioside G(D1a) and G(M1) inhibit the degranulation and cytotoxicity through stabilizing lipid raft. Gangliosides have potentials to be therapeutic tool or clinical prophylaxis for wasp stinging.
authors.affiliation: Department of Food Science and Technology, Graduate School of Marine Science and Technology, Tokyo.
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Nishikawa
authors.forename: Seiichi
authors.initials: S
authors.lastname: Kitani
mesh_terms: D000818:Animals; D016923:Cell Death / Q000187:drug effects; D015550:Cell Degranulation / Q000187:drug effects*; D003239:Connective Tissue Cells / Q000166:cytology*; D004285:Dogs; D019204:GTP-Binding Proteins / Q000378:metabolism; D005732:Gangliosides / Q000494:pharmacology*; D036341:Intercellular Signaling Peptides and Proteins; D042541:Intracellular Space / Q000187:drug effects / Q000378:metabolism; D008407:Mast Cells / Q000187:drug effects* / Q000473:pathology / Q000502:physiology; D021962:Membrane Microdomains / Q000187:drug effects* / Q000378:metabolism; D010455:Peptides / Q000037:antagonists & inhibitors* / Q000494:pharmacology / Q000633:toxicity*; D017382:Reactive Oxygen Species / Q000378:metabolism; D014862:Wasp Venoms / Q000037:antagonists & inhibitors* / Q000494:pharmacology / Q000633:toxicity*
chemical_list: D005732:Gangliosides; D036341:Intercellular Signaling Peptides and Proteins; D010455:Peptides; D017382:Reactive Oxygen Species; D014862:Wasp Venoms; C037500:mastoparan; D019204:GTP-Binding Proteins