title: miR-146b antagomir-treated human Tregs acquire increased GVHD inhibitory potency.
abstract: CD4(+)CD25(+)FoxP3(+) thymic-derived regulatory T cells (tTregs) are indispensable for maintaining immune system equilibrium. Adoptive transfer of tTregs is an effective means of suppressing graft-versus-host disease (GVHD) in murine models and in early human clinical trials. Tumor necrosis factor receptor-associated factor 6 (TRAF6), an ubiquitin-conjugating enzyme that mediates nuclear factor κB (NF-κB) activation, plays an essential role in modulating regulatory T cell survival and function. MicroRNAs (miRNAs) are noncoding RNAs, which mediate RNA silencing and posttranscriptional gene repression. By performing comprehensive TaqMan Low Density Array miRNA assays, we identified 10 miRNAs differentially regulated in human tTreg compared with control T cells. One candidate, miR-146b, is preferentially and highly expressed in human naive tTregs compared with naive CD4 T cells. miRNA prediction software revealed that TRAF6 was the one of the top 10 scored mRNAs involved tTreg function with the highest probability as a potential miR-146b target. Antagomir-mediated knockdown of miRNA-146b, but not another miRNA-146 family member (miRNA-146a), enhanced TRAF6 expression. TRAF6, in turn, increases NF-κB activation, which is essential for tTreg function as well as Foxp3 protein and antiapoptotic gene expression, and downregulates proapoptotic gene expression. miR-146b knockdown increased the nuclear localization and expression of genes regulated by NF-κB, which was associated with enhanced tTreg survival, proliferation, and suppressive function measured in vitro and in vivo. TRAF6 inhibition had the opposite effects. We conclude that an miR-146b-TRAF6-NF-κB-FoxP3 signaling pathway restrains regulatory T cell survival, proliferation, and suppressor function. In vitro exposure of human tTregs to miR-146b antagomirs can be exploited to improve the clinical efficacy of human adoptive tTreg transfer in a GVHD setting.
authors.affiliation: Translational Medicine Research Center, Affiliated Jiangning Hospital, and Liver Transplantation Center, First Affiliated Hospital, Nanjing Medical University, Nanjing, China; Division of Blood and Marrow Transplantation, Department of Pediatrics, University of Minnesota Cancer Center, Minneapolis, MN;
authors.forename: Yunjie
authors.identifier: 0000-0003-3143-3581
authors.initials: Y
authors.lastname: Lu
authors.affiliation: Division of Blood and Marrow Transplantation, Department of Pediatrics, University of Minnesota Cancer Center, Minneapolis, MN;
authors.forename: Keli L
authors.initials: KL
authors.lastname: Hippen
authors.affiliation: Division of Blood and Marrow Transplantation, Department of Pediatrics, University of Minnesota Cancer Center, Minneapolis, MN;
authors.forename: Amanda L
authors.initials: AL
authors.lastname: Lemire
authors.affiliation: Translational Medicine Research Center, Affiliated Jiangning Hospital, and Liver Transplantation Center, First Affiliated Hospital, Nanjing Medical University, Nanjing, China;
authors.forename: Jian
authors.initials: J
authors.lastname: Gu
authors.affiliation: Translational Medicine Research Center, Affiliated Jiangning Hospital, and Liver Transplantation Center, First Affiliated Hospital, Nanjing Medical University, Nanjing, China;
authors.forename: Weizhi
authors.initials: W
authors.lastname: Wang
authors.affiliation: Translational Medicine Research Center, Affiliated Jiangning Hospital, and Liver Transplantation Center, First Affiliated Hospital, Nanjing Medical University, Nanjing, China;
authors.forename: Xuhao
authors.initials: X
authors.lastname: Ni
authors.affiliation: Division of Hematology, Department of Internal Medicine and Comprehensive Cancer Center, The Ohio State University, Columbus, OH;
authors.forename: Parvathi
authors.initials: P
authors.lastname: Ranganathan
authors.affiliation: Abramson Family Cancer Center Research Institute, University of Pennsylvania Cancer Center, Philadelphia, PA;
authors.forename: Bruce L
authors.initials: BL
authors.lastname: Levine
authors.affiliation: Abramson Family Cancer Center Research Institute, University of Pennsylvania Cancer Center, Philadelphia, PA;
authors.forename: James L
authors.initials: JL
authors.lastname: Riley
authors.affiliation: Abramson Family Cancer Center Research Institute, University of Pennsylvania Cancer Center, Philadelphia, PA;
authors.forename: Carl H
authors.initials: CH
authors.lastname: June
authors.affiliation: Department of Surgery, Center for Transplantation Sciences, Massachusetts General Hospital and Harvard Medical School, Boston, MA; and.
authors.forename: Laurence A
authors.initials: LA
authors.lastname: Turka
authors.affiliation: Immunotherapy Center, Medical College of Georgia, Augusta, GA.
authors.forename: David H
authors.initials: DH
authors.lastname: Munn
authors.affiliation: Division of Hematology, Department of Internal Medicine and Comprehensive Cancer Center, The Ohio State University, Columbus, OH;
authors.forename: Ramiro
authors.initials: R
authors.lastname: Garzon
authors.affiliation: Translational Medicine Research Center, Affiliated Jiangning Hospital, and Liver Transplantation Center, First Affiliated Hospital, Nanjing Medical University, Nanjing, China;
authors.forename: Ling
authors.initials: L
authors.lastname: Lu
authors.affiliation: Division of Blood and Marrow Transplantation, Department of Pediatrics, University of Minnesota Cancer Center, Minneapolis, MN;
authors.forename: Bruce R
authors.initials: BR
authors.lastname: Blazar
mesh_terms: D000818:Animals; D000070416:Antagomirs / Q000235:genetics*; D017209:Apoptosis; D049109:Cell Proliferation; D005786:Gene Expression Regulation; D006086:Graft vs Host Disease / Q000235:genetics / Q000276:immunology / Q000517:prevention & control*; D006801:Humans; D051379:Mice; D016688:Mice, Inbred NOD; D016513:Mice, SCID; D035683:MicroRNAs / Q000235:genetics*; D016328:NF-kappa B / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D050378:T-Lymphocytes, Regulatory / Q000276:immunology* / Q000378:metabolism; D048029:TNF Receptor-Associated Factor 6 / Q000235:genetics / Q000378:metabolism*
chemical_list: D000070416:Antagomirs; C542542:MIRN146 microRNA, human; D035683:MicroRNAs; D016328:NF-kappa B; D048029:TNF Receptor-Associated Factor 6