title: RNA interference screen in primary human T cells reveals FLT3 as a modulator of IL-10 levels.
abstract: Functional studies of human primary immune cells have been hampered by the lack of tools to silence gene functions. In this study, we report the application of a lentiviral RNA interference library in primary human T cells. Using a subgenomic short hair RNA library targeting approximately 1000 signaling genes, we identified novel genes that control the levels of IL-10 produced. IL-10 is a potent anti-inflammatory cytokine secreted by several cell types, including T regulatory type 1 cells, a subset of T regulatory cells that exert their suppressive activity through IL-10 secretion. FLT3, a known hematopoeitic growth factor, was found to be a negative regulator of IL-10 levels in activated T cells. This was based on several observations. First, FLT3 and its ligand (FL) were both induced by T cell activation. Second, silencing of FLT3 led to increased IL-10 levels, whereas addition of FL suppressed IL-10 secretion and increased FLT3 surface levels. Third, engagement of CD46, a known inducer of T regulatory type 1 cells, upregulated surface FLT3, and secreted FL, which then inhibited IL-10 production by T cells. Hence, FL and FLT3 form a novel regulatory feedback loop that limits IL-10 production in T cells. Our results identified FLT3 as a new regulator of T cell function and offer a strategy to genetically dissect specific pathways in T cells.
authors.affiliation: Center for Neurologic Diseases, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA. a.astier@ed.ac.uk
authors.forename: Anne L
authors.initials: AL
authors.lastname: Astier
authors.forename: Gaëlle
authors.initials: G
authors.lastname: Beriou
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Eisenhaure
authors.forename: Stephen M
authors.initials: SM
authors.lastname: Anderton
authors.forename: David A
authors.initials: DA
authors.lastname: Hafler
authors.forename: Nir
authors.initials: N
authors.lastname: Hacohen
mesh_terms: D002478:Cells, Cultured; D025461:Feedback, Physiological; D005786:Gene Expression Regulation; D015723:Gene Library; D006801:Humans; D007155:Immunologic Factors; D016753:Interleukin-10 / Q000235:genetics / Q000378:metabolism*; D016086:Lentivirus / Q000235:genetics; D008024:Ligands; D008213:Lymphocyte Activation; D051916:Membrane Cofactor Protein / Q000378:metabolism; D034622:RNA Interference / Q000276:immunology; D034741:RNA, Small Interfering / Q000494:pharmacology*; D013601:T-Lymphocytes / Q000276:immunology*; D051941:fms-Like Tyrosine Kinase 3 / Q000276:immunology*
chemical_list: D007155:Immunologic Factors; D008024:Ligands; D051916:Membrane Cofactor Protein; D034741:RNA, Small Interfering; D016753:Interleukin-10; D051941:fms-Like Tyrosine Kinase 3