title: Lowering glycosphingolipid levels in CD4+ T cells attenuates T cell receptor signaling, cytokine production, and differentiation to the Th17 lineage.
abstract: Lipid rafts reportedly have a role in coalescing key signaling molecules into the immunological synapse during T cell activation, thereby modulating T cell receptor (TCR) signaling activity. Recent findings suggest that a correlation may exist between increased levels of glycosphingolipids (GSLs) in the lipid rafts of T cells and a heightened response of those T cells toward activation. Here, we show that lowering the levels of GSLs in CD4(+) T cells using a potent inhibitor of glucosylceramide synthase (Genz-122346) led to a moderation of the T cell response toward activation. TCR proximal signaling events, such as phosphorylation of Lck, Zap70 and LAT, as well as early Ca(2+) mobilization, were attenuated by treatment with Genz-122346. Concomitant with these events were significant reductions in IL-2 production and T cell proliferation. Similar findings were obtained with CD4(+) T cells isolated from transgenic mice genetically deficient in GM3 synthase activity. Interestingly, lowering the GSL levels in CD4(+) T cells by either pharmacological inhibition or disruption of the gene for GM3 synthase also specifically inhibited the differentiation of T cells to the Th(17) lineage but not to other Th subsets in vitro. Taken together with the recently reported effects of Raftlin deficiency on Th(17) differentiation, these results strongly suggest that altering the GSL composition of lipid rafts modulates TCR signaling activity and affects Th(17) differentiation.
authors.affiliation: Genzyme Corporation, Framingham, Massachusetts 01701-9322, USA.
authors.forename: Yunxiang
authors.initials: Y
authors.lastname: Zhu
authors.forename: Nathan
authors.initials: N
authors.lastname: Gumlaw
authors.forename: Jozsef
authors.initials: J
authors.lastname: Karman
authors.forename: Hongmei
authors.initials: H
authors.lastname: Zhao
authors.forename: Jinhua
authors.initials: J
authors.lastname: Zhang
authors.forename: Ji-Lei
authors.initials: JL
authors.lastname: Jiang
authors.forename: Pete
authors.initials: P
authors.lastname: Maniatis
authors.forename: Andrea
authors.initials: A
authors.lastname: Edling
authors.forename: Wei-Lien
authors.initials: WL
authors.lastname: Chuang
authors.forename: Craig
authors.initials: C
authors.lastname: Siegel
authors.forename: James A
authors.initials: JA
authors.lastname: Shayman
authors.forename: Johanne
authors.initials: J
authors.lastname: Kaplan
authors.forename: Canwen
authors.initials: C
authors.lastname: Jiang
authors.forename: Seng H
authors.initials: SH
authors.lastname: Cheng
mesh_terms: D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology* / Q000378:metabolism*; D002454:Cell Differentiation; D019070:Cell Lineage; D016207:Cytokines / Q000096:biosynthesis; D006028:Glycosphingolipids / Q000037:antagonists & inhibitors*; D054992:Immunological Synapses; D021962:Membrane Microdomains; D051379:Mice; D008822:Mice, Transgenic; D011948:Receptors, Antigen, T-Cell / Q000378:metabolism*; D015398:Signal Transduction; D058504:Th17 Cells / Q000166:cytology*
chemical_list: D016207:Cytokines; D006028:Glycosphingolipids; D011948:Receptors, Antigen, T-Cell