title: Sulfatides inhibit leukotriene synthesis in human polymorphonuclear granulocytes by a mechanism involving lipid rearrangement in intracellular membranes.
abstract: Sulfatides - sulfated derivatives of galactocerebroside - are endogenous ligands for P- and L-selectins and are able to induce intracellular signaling in neutrophils through a L-selectin dependent pathway. Sulfatides are implicated in a variety of physiological functions and have been found to suppress the synthesis of 5-lipoxygenase (5-LO) metabolites and impede 5-LO translocation to the nuclear envelope in adherent human polymorphonuclear leukocytes (PMNs) [Sud'ina, G. F., Brock, T. G., Pushkareva, M. A., Galkina, S. I., Turutin, D. V., Peters-Golden, M., et al. (2001). Sulphatides trigger polymorphonuclear granulocyte spreading on collagen-coated surfaces and inhibit subsequent activation of 5-lipoxygenase. The Biochemical Journal, 359, 621-629]. In this study we investigated the mechanism of the leukotriene (LT) synthesis inhibition by sulfatides. Sulfatides neither attenuated the ionophore-induced rise in [Ca(2+)](i) nor promoted PKA activation. We demonstrated that sulfatides directly inhibited 5-LO enzyme activity in a cell-free assay. BODIPY-labeled sulfatides were able to rapidly penetrate into the cells. Sulfatides induced rearrangement and redistribution of cytoskeletal components in adherent PMNs. The lipid incorporation as well as sulfatide-induced inhibition of LT synthesis were abolished by cytochalasin D, an inhibitor of actin polymerization and endocytosis. Importantly, sulfatides caused a prominent intracellular cholesterol redistribution, increasing its abundance at the uropod region. On the basis of these data, we suggest that increased cholesterol accumulation in cell compartments represents a novel mechanism by which sulfatides abrogate 5-LO translocation and activation.
authors.affiliation: A.N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow 119992, Russia. zoryana@belozersky.msu.ru
authors.forename: Zoryana V
authors.initials: ZV
authors.lastname: Grishina
authors.forename: Marina A
authors.initials: MA
authors.lastname: Pushkareva
authors.forename: Olga Yu
authors.initials: OY
authors.lastname: Pletjushkina
authors.forename: Georg
authors.initials: G
authors.lastname: Reiser
authors.forename: Marc
authors.initials: M
authors.lastname: Peters-Golden
authors.forename: Galina F
authors.initials: GF
authors.lastname: Sud'ina
mesh_terms: D001094:Arachidonate 5-Lipoxygenase / Q000096:biosynthesis*; D002474:Cell-Free System; D002784:Cholesterol / Q000378:metabolism; D004794:Enzyme Repression; D005455:Fluorescent Antibody Technique; D006801:Humans; D007425:Intracellular Membranes / Q000187:drug effects / Q000648:ultrastructure; D015289:Leukotrienes / Q000096:biosynthesis*; D008053:Lipid Mobilization / Q000187:drug effects; D016859:Lipoxygenase Inhibitors; D008870:Microtubules / Q000378:metabolism / Q000648:ultrastructure; D009504:Neutrophils / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D013433:Sulfoglycosphingolipids / Q000378:metabolism* / Q000494:pharmacology