title: MicroRNA regulation of STAT4 protein expression: rapid and sensitive modulation of IL-12 signaling in human natural killer cells.
abstract: IL-12 exerts several regulatory effects on natural killer (NK) cells by activating IL-12 signaling. IL-12 signaling is tightly auto-regulated to control its onset and termination, with prolonged IL-12 treatment resulting in IL-12 hyporesponsiveness. However, the mechanisms underlying IL-12 auto-regulation are still unclear. In this study we report that prolonged IL-12 treatment significantly up-regulates microRNAs (miRNAs), including miR-132, -212, and -200a in primary human NK cells. This up-regulation correlates temporally with gradually decreasing STAT4 levels and decreasing IFN-γ expression, after an initial increase within the first 16 hours of IL-12 treatment. The IL-12 hyporesponsiveness is dependent on IL-12 concentration, and associated up-regulation of miR-132, -212, and -200a. Furthermore, IL-12-hyporesponsive cells regain responsiveness of IFN-γ production 24 hours after IL-12 removal, which correlates with decreases in miR-132, -212, and -200a levels. Overexpression of miR-132, -212, and -200a by transfection into NK cells mimics IL-12 priming, inducing IL-12 hyporesponsiveness, whereas transfection of miR-132, -212, and -200a inhibitors largely abolishes IL-12 induction of IL-12 hyporesponsiveness. These data suggest that miR-132, -212, and -200a up-regulation during prolonged IL-12 treatment, negatively regulates the IL-12 signaling pathway by reducing STAT4 expression in primary human NK cells.
authors.affiliation: Laboratory of Molecular Virology, Center for Biologics Evaluation and Research, Food and Drug Administration, Rockville, MD 20892, USA.
authors.forename: Yong
authors.initials: Y
authors.lastname: Huang
authors.forename: YingFeng
authors.initials: Y
authors.lastname: Lei
authors.forename: Hai
authors.initials: H
authors.lastname: Zhang
authors.forename: LiChao
authors.initials: L
authors.lastname: Hou
authors.forename: Mingjie
authors.initials: M
authors.lastname: Zhang
authors.forename: Andrew I
authors.initials: AI
authors.lastname: Dayton
mesh_terms: D020413:3' Untranslated Regions / Q000235:genetics; D001665:Binding Sites / Q000235:genetics; D015153:Blotting, Western; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D005434:Flow Cytometry; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D007371:Interferon-gamma / Q000235:genetics / Q000378:metabolism; D018664:Interleukin-12 / Q000494:pharmacology; D007694:Killer Cells, Natural / Q000187:drug effects / Q000378:metabolism; D035683:MicroRNAs / Q000235:genetics* / Q000378:metabolism; D014176:Protein Biosynthesis / Q000235:genetics*; D053707:Receptors, Interleukin-12 / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D050797:STAT4 Transcription Factor / Q000235:genetics* / Q000378:metabolism; D015854:Up-Regulation / Q000187:drug effects
chemical_list: D020413:3' Untranslated Regions; C547077:MIRN132 microRNA, human; C533896:MIRN200 microRNA, human; C551411:MIRN212 microRNA, human; D035683:MicroRNAs; D053707:Receptors, Interleukin-12; D050797:STAT4 Transcription Factor; C494090:STAT4 protein, human; D018664:Interleukin-12; D007371:Interferon-gamma