title: Src homology 2-containing inositol 5'-phosphatase 1 negatively regulates IFN-gamma production by natural killer cells stimulated with antibody-coated tumor cells and interleukin-12.
abstract: We have previously shown that natural killer (NK) cells secrete a distinct profile of immunomodulatory cytokines in response to dual stimulation with antibody-coated tumor cells and interleukin-12 (IL-12). This NK cell cytokine response is dependent on synergistic signals mediated by the activating receptor for the Fc portion of IgG (FcgammaRIIIa) and the IL-12 receptor (IL-12R), both constitutively expressed on NK cells. The phosphatase Src homology 2-containing inositol 5'-phosphatase 1 (SHIP1) is known to exert inhibitory effects on Fc receptor (FcR) signaling via its enzymatic activity on phosphatidylinositol 3-kinase (PI3-K) products within many cells of the immune system, most notably mast cells, B cells, and monocytes. However, its activity in the context of FcR activation on NK cells has not been fully explored. The current study focused on the regulation of FcgammaRIIIa-induced NK cell cytokine production by SHIP1. Inhibitor studies showed that NK cell IFN-gamma production following FcR stimulation in the presence of IL-12 depended, in part, on the downstream products of PI3-K. Overexpression of wild-type (WT) SHIP1, but not a catalytic-deficient mutant, via retroviral transfection of primary human NK cells, resulted in a >70% reduction of NK cell IFN-gamma production in response to costimulation. In addition, NK cells from SHIP1-/- mice produced 10-fold greater amounts of IFN-gamma following culture with antibody-coated tumor cells plus IL-12 compared with NK cells from WT mice. Further, activation of the mitogen-activated protein kinase (MAPK) family member extracellular signal-regulated kinase (Erk; a downstream target of PI3-K) was significantly enhanced within SHIP1-/- NK cells compared with WT NK cells following costimulation. Pharmacologic inhibition of Erk activity, but not Jnk MAPK activity, led to significantly decreased IFN-gamma production from both SHIP1-/- and WT NK cells under these conditions. These results are the first to show a physiologic role for SHIP1 in the regulation of NK cell cytokine production and implicate PI3-K in the induction of MAPK signal transduction following costimulation of NK cells via the FcR and the IL-12R.
authors.affiliation: Department of Molecular Virology, Immunology, and Medical Genetics, Ohio State University, Columbus, OH 43210, USA.
authors.forename: Robin
authors.initials: R
authors.lastname: Parihar
authors.forename: Rossana
authors.initials: R
authors.lastname: Trotta
authors.forename: Julie M
authors.initials: JM
authors.lastname: Roda
authors.forename: Amy K
authors.initials: AK
authors.lastname: Ferketich
authors.forename: Susheela
authors.initials: S
authors.lastname: Tridandapani
authors.forename: Michael A
authors.initials: MA
authors.lastname: Caligiuri
authors.forename: William E
authors.initials: WE
authors.lastname: Carson
mesh_terms: D000818:Animals; D000920:Antibody-Dependent Cell Cytotoxicity; D004789:Enzyme Activation; D048049:Extracellular Signal-Regulated MAP Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D005260:Female; D006801:Humans; D000072181:Inositol Polyphosphate 5-Phosphatases; D007371:Interferon-gamma / Q000037:antagonists & inhibitors / Q000096:biosynthesis* / Q000276:immunology; D018664:Interleukin-12 / Q000276:immunology* / Q000494:pharmacology; D007694:Killer Cells, Natural / Q000187:drug effects / Q000201:enzymology / Q000276:immunology*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D000072183:Phosphatidylinositol-3,4,5-Trisphosphate 5-Phosphatases; D010744:Phosphoric Monoester Hydrolases / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000378:metabolism*; D010766:Phosphorylation; D017452:Receptors, IgG; D018123:Receptors, Interleukin / Q000276:immunology / Q000378:metabolism; D053707:Receptors, Interleukin-12; D014162:Transfection
chemical_list: C496124:FCGR3A protein, human; D017452:Receptors, IgG; D018123:Receptors, Interleukin; D053707:Receptors, Interleukin-12; D018664:Interleukin-12; D007371:Interferon-gamma; D048049:Extracellular Signal-Regulated MAP Kinases; D010744:Phosphoric Monoester Hydrolases; D000072181:Inositol Polyphosphate 5-Phosphatases; C000606430:INPP5D protein, human; C000606433:Inpp5d protein, mouse; D000072183:Phosphatidylinositol-3,4,5-Trisphosphate 5-Phosphatases