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Glycosylation‐dependent interaction between CD69 and S100A8/S100A9 complex is required for regulatory T‐cell differentiation
Author(s) -
Lin ChihRu,
Wei TongYou Wade,
Tsai HsienYu,
Wu YingTa,
Wu PeiYu,
Chen ShuiTein
Publication year - 2015
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fj.15-273987
Subject(s) - cd69 , biology , microbiology and biotechnology , immune system , gene silencing , receptor , cellular differentiation , glycosylation , immunology , t cell , biochemistry , il 2 receptor , gene
Cluster of differentiation (CD) 69 is a leukocyte activation receptor involved in the maintenance of immune homeostasis and is positively selected in activated regulatory T (T reg ) cells, implicating its role during T reg ‐cell differentiation. By RNA interference, we show that CD69 is not sufficient to support the conversion of CD4 + naive T cells into T reg cells, whereas it does that of human peripheral blood mononuclear cells (hPBMCs) ( P < 0.01), suggesting that a ligand‐receptor interaction is required for CD69 function. Using immunoprecipitation and mass spectrometry, we identified the S100A8/S100A9 complex as the natural ligand of CD69 in hPBMCs. CD69 specifically associates with S100A8/S100A9 complex as confirmed by in vitro binding and competition assay, and the treatment of CD69 with peptide‐ N ‐glycosidase significantly abolishes such association. In agreement, the glycomics analysis determines the glycosylation site and the N ‐glycan composition of CD69, and terminal removal of sialic acid from that N ‐linked glycans reverses the generation of forkhead box P3‐positive T reg cells (23.21%; P < 0.05). More specifically, we showed that CD69‐S100A8/S100A9 association is required for the up‐regulation of suppressor of cytokine signaling 3 resulting in inhibited signaling of signal transducer and activator of transcription 3 (36.54% increase upon CD69 silencing; P < 0.01). This might in turn support the secretion of key regulator TGF‐β (∼3.28‐fold decrease upon CD69 silencing; P < 0.05), leading to reduced production of IL‐4 in hPBMCs. Our results demonstrate the functional and mechanistic interplays between CD69 and S100A8/S100A9 in supporting T reg ‐cell differentiation.—Lin, C.‐R., Wei, T.‐Y. W., Tsai, H.‐Y., Wu, Y.‐T., Wu, P.‐Y., Chen, S.‐T. Glycosylation‐dependent interaction between CD69 and S100A8/S100A9 complex is required for regulatory T‐cell differentiation. FASEB J. 29, 5006–5017 (2015). www.fasebj.org