In Vitro and In Vivo Evidence That the PP2A Inhibitor SET Regulates IFN-γ Production in Monokine-Stimulated Natural Killer Cells.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 928-928 ◽  
Author(s):  
Rossana Trotta ◽  
Jessica Dal Col ◽  
Jeffrey Allard ◽  
Paolo Neviani ◽  
Ramasamy Santhanam ◽  
...  
Keyword(s):  
Nk Cells ◽  
Natural Killer ◽  
Interferon Γ ◽  
Oligonucleotide Array ◽  
Pp2a Activity ◽  
Protein Levels ◽  
Ifn Γ ◽  
Protein Phosphatase Type

Abstract Monokines (i.e. IL-12, IL-18 and IL-15) induce natural killer (NK) cells to produce interferon-γ (IFN-γ), which is critical for monocyte clearance of infectious pathogens and tumor surveillance. To identify new regulators of IFN-γ production we performed oligonucleotide array analysis of unstimulated and IL-12- and IL-18-stimulated NK92 cells. Among the subset of mRNAs differentially regulated in monokine-stimulated cells, we found SET, a potent inhibitor of the protein phosphatase type 2A (PP2A). SET mRNA and/or protein levels were upregulated in IL-12/IL-18- and IL-12/IL-15-stimulated primary human NK cells. Interestingly, the SET protein is also selectively increased in the resting CD56bright NK subset, which is a potent producer of IFN-γ relative to the CD56dim NK subset. To determine whether SET positively regulates IFN-γ production by inhibiting PP2A activity, we employed RNAi and interfered with SET expression in NK92 cells. SET downregulation inhibited IFN-γ secretion by IL-12/IL-18, IL-12/IL-15- or IL-15/IL-18-stimulated NK92 cells. By contrast, ectopic SET expression increased IFN-γ production in monokine-stimulated NK92 and primary human NK cells. Because downregulation of SET augmented PP2A activity in NK92 cells, we sought to investigate whether pharmacologic activation of PP2A inhibits the ability of NK cells to produce IFN-γ. Indeed, suppression of IFN-γ expression and secretion was also observed upon treatment of NK92 and primary NK cells with 1,9-dideoxy-forskolin, a known inducer of PP2A activity. Accordingly, NK cells from mice treated with 1.9-dideoxy-forskolin produced less IFN-γ in response to in vivo monokine stimulation than did NK cells from vehicle-treated mice. Mechanistically, activation of PP2A by SET knock-down or 1,9-dideoxy-forskolin treatment leads to inhibition of ERK1/2, p65RelA and STAT5 activity in monokine-stimulated NK cells. Because these signaling molecules are important for IFN-γ production by monokine-stimulated NK cells, our results strongly suggest that monokine induction of SET expression in NK cells is essential for limiting PP2A activity that, otherwise, would negatively impact the ability of NK cells to produce and release optimal levels of IFN-γ.

Contribution of Natural Killer Cells to Inhibition of Angiogenesis by Interleukin-12

Blood ◽  
1999 ◽  
Vol 93 (5) ◽  
pp. 1612-1621 ◽  
Author(s):  
Lei Yao ◽  
Cecilia Sgadari ◽  
Keizo Furuke ◽  
Eda T. Bloom ◽  
Julie Teruya-Feldstein ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Nk Cells ◽  
Natural Killer ◽  
Cell Function ◽  
Nk Cell ◽  
Primary Cultures ◽  
Interleukin 12 ◽  
Ifn Γ

Abstract Interleukin-12 (IL-12) inhibits angiogenesis in vivo by inducing interferon-γ (IFN-γ) and other downstream mediators. Here, we report that neutralization of natural killer (NK) cell function with antibodies to either asialo GM1 or NK 1.1 reversed IL-12 inhibition of basic fibroblast growth factor (bFGF)-induced angiogenesis in athymic mice. By immunohistochemistry, those sites where bFGF-induced neovascularization was inhibited by IL-12 displayed accumulation of NK cells and the presence of IP-10–positive cells. Based on expression of the cytolytic mediators perforin and granzyme B, the NK cells were locally activated. Experimental Burkitt lymphomas treated locally with IL-12 displayed tumor tissue necrosis, vascular damage, and NK-cell infiltration surrounding small vessels. After activation in vitro with IL-12, NK cells from nude mice became strongly cytotoxic for primary cultures of syngeneic aortic endothelial cells. Cytotoxicity was neutralized by antibodies to IFN-γ. These results document that NK cells are required mediators of angiogenesis inhibition by IL-12, and provide evidence that NK-cell cytotoxicity of endothelial cells is a potential mechanism by which IL-12 can suppress neovascularization.

Inflammation restraining effects of prostaglandin E2 on natural killer–dendritic cell (NK-DC) interaction are imprinted during DC maturation

Blood ◽  
2011 ◽  
Vol 118 (9) ◽  
pp. 2473-2482 ◽  
Author(s):  
Catharina H. M. J. Van Elssen ◽  
Joris Vanderlocht ◽  
Tammy Oth ◽  
Birgit L. M. G. Senden-Gijsbers ◽  
Wilfred T. V. Germeraad ◽  
...  
Keyword(s):  
Dendritic Cell ◽  
Immune Responses ◽  
Nk Cells ◽  
Natural Killer ◽  
Nk Cell ◽  
T Helper 1 ◽  
Ifn Γ ◽  
Dc Maturation

Abstract Among prostaglandins (PGs), PGE2 is abundantly expressed in various malignancies and is probably one of many factors promoting tumor growth by inhibiting tumor immune surveillance. In the current study, we report on a novel mechanism by which PGE2 inhibits in vitro natural killer–dendritic cell (NK-DC) crosstalk and thereby innate and adaptive immune responses via its effect on NK-DC crosstalk. The presence of PGE2 during IFN-γ/membrane fraction of Klebsiella pneumoniae DC maturation inhibits the production of chemokines (CCL5, CCL19, and CXCL10) and cytokines (IL-12 and IL-18), which is cAMP-dependent and imprinted during DC maturation. As a consequence, these DCs fail to attract NK cells and show a decreased capacity to trigger NK cell IFN-γ production, which in turn leads to reduced T-helper 1 polarization. In addition, the presence of PGE2 during DC maturation impairs DC-mediated augmentation of NK-cell cytotoxicity. Opposed to their inhibitory effects on peripheral blood–derived NK cells, PGE2 matured DCs induce IL-22 secretion of inflammation constraining NKp44+ NK cells present in mucosa-associated lymphoid tissue. The inhibition of NK-DC interaction is a novel regulatory property of PGE2 that is of possible relevance in dampening immune responses in vivo.

Natural-killer cells and dendritic cells: “l'union fait la force”

Blood ◽  
2005 ◽  
Vol 106 (7) ◽  
pp. 2252-2258 ◽  
Author(s):  
Thierry Walzer ◽  
Marc Dalod ◽  
Scott H. Robbins ◽  
Laurence Zitvogel ◽  
Eric Vivier
Keyword(s):  
Dendritic Cells ◽  
Nk Cells ◽  
Natural Killer ◽  
Cell Activation ◽  
Nk Cell ◽  
Interleukin 12 ◽  
Cell Contact ◽  
Ifn Γ

AbstractSeveral recent publications have focused on the newly described interactions between natural-killer (NK) cells and dendritic cells (DCs). Activated NK cells induce DC maturation either directly or in synergy with suboptimal levels of microbial signals. Immature DCs appear susceptible to autologous NK-cell-mediated cytolysis while mature DCs are protected. NK-cell-induced DC activation is dependent on both tumor necrosis factor-α (TNF-α)/interferon-γ (IFN-γ) secretion and a cell-cell contact involving NKp30. In vitro, interleukin-12 (IL-12)/IL-18, IL-15, and IFN-α/β production by activated DCs enhance, in turn, NK-cell IFN-γ production, proliferation, and cytotoxic potential, respectively. In vivo, NK-cell/DC interactions may occur in lymphoid organs as well as in nonlymphoid tissues, and their consequences are multiple. By inducing DC activation, NK-cell activation induced by tumor cells can indirectly promote antitumoral T-cell responses. Reciprocally, DCs activated through Toll-like receptors (TLRs) induce potent NK-cell activation in antiviral responses. Thus, DCs and NK cells are equipped with complementary sets of receptors that allow the recognition of various pathogenic agents, emphasizing the role of NK-cell/DC crosstalk in the coordination of innate and adaptive immune responses.

scholarly journals Functional Dichotomy in Natural Killer Cell Signaling

2001 ◽  
Vol 193 (12) ◽  
pp. 1413-1424 ◽  
Author(s):  
Francesco Colucci ◽  
Eleftheria Rosmaraki ◽  
Søren Bregenholt ◽  
Sandrine I. Samson ◽  
Vincenzo Di Bartolo ◽  
...  
Keyword(s):  
Nk Cells ◽  
Natural Killer ◽  
Nk Cell ◽  
Killer Cell ◽  
Surface Receptors ◽  
Nk T Cells ◽  
Nk Cell Differentiation ◽  
Ifn Γ

The product of the protooncogene Vav1 participates in multiple signaling pathways and is a critical regulator of antigen–receptor signaling in B and T lymphocytes, but its role during in vivo natural killer (NK) cell differentiation is not known. Here we have studied NK cell development in Vav1−/− mice and found that, in contrast to T and NK-T cells, the absolute numbers of phenotypically mature NK cells were not reduced. Vav1−/− mice produced normal amounts of interferon (IFN)-γ in response to Listeria monocytogenes and controlled early infection but showed reduced tumor clearance in vivo. In vitro stimulation of surface receptors in Vav1−/− NK cells resulted in normal IFN-γ production but reduced tumor cell lysis. Vav1 was found to control activation of extracellular signal-regulated kinases and exocytosis of cytotoxic granules. In contrast, conjugate formation appeared to be only mildly affected, and calcium mobilization was normal in Vav1−/− NK cells. These results highlight fundamental differences between proximal signaling events in T and NK cells and suggest a functional dichotomy for Vav1 in NK cells: a role in cytotoxicity but not for IFN-γ production.

scholarly journals Ascophyllan Induces Activation of Natural Killer Cells in Mice In Vivo and In Vitro

Marine Drugs ◽  
2019 ◽  
Vol 17 (4) ◽  
pp. 197 ◽  
Author(s):  
Wei Zhang ◽  
Takasi Okimura ◽  
Tatsuya Oda ◽  
Jun-O Jin
Keyword(s):  
Nk Cells ◽  
Natural Killer ◽  
Cell Activation ◽  
Nk Cell ◽  
Promote Cell Proliferation ◽  
Ifn Γ ◽  
Human And Mouse ◽  
Marine Polysaccharide

Natural marine polysaccharides have demonstrated immune stimulatory effects in both mice and humans. Our previous study compared the ability of ascophyllan and fucoidan to activate human and mouse dendritic cells (DCs). In this study, we further examined the effect of ascophyllan on the activation of mouse natural killer (NK) cells in vivo and in vitro and compared it to that of fucoidan, a well-studied natural marine polysaccharide. Specifically, administration of ascophyllan to C57BL/6 mice increased the number of NK cells in the spleen when compared to the number in PBS-treated mice. Moreover, the number of IFN-γ-producing NK cells and expression of CD69 were markedly upregulated by ascophyllan treatment. Ascophyllan treatment also induced IFN-γ production and CD69 upregulation in isolated NK cells, but did not promote cell proliferation. Finally, ascophyllan treatment increased the cytotoxicity of NK cells against Yac-1 cells. The effects of ascophyllan on NK cell activation were considerably stronger than those of fucoidan. These data demonstrated that ascophyllan promotes NK cell activation both in mice and in vitro, and its stimulatory effect on NK cells is stronger than that of fucoidan.

scholarly journals Hlx homeobox transcription factor negatively regulates interferon-γ production in monokine-activated natural killer cells

Blood ◽  
2006 ◽  
Vol 109 (6) ◽  
pp. 2481-2487 ◽  
Author(s):  
Brian Becknell ◽  
Tiffany L. Hughes ◽  
Aharon G. Freud ◽  
Bradley W. Blaser ◽  
Jianhua Yu ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Nk Cells ◽  
Natural Killer ◽  
Molecular Mechanisms ◽  
Interferon Γ ◽  
Tumor Surveillance ◽  
Protein Levels ◽  
Homeobox Transcription Factor ◽  
Ifn Γ

Abstract Natural killer (NK) cells contribute to host immunity, including tumor surveillance, through the production of interferon gamma (IFN-γ). Although there is some knowledge about molecular mechanisms that induce IFN-γ in NK cells, considerably less is known about the mechanisms that reduce its expression. Here, we investigate the role of the Hlx transcription factor in IFN-γ production by NK cells. Hlx expression is induced in monokine-activated NK cells, but with delayed kinetics compared to IFN-γ. Ectopic Hlx expression decreases IFN-γ synthesis in primary human NK cells and IFN-γ promoter activity in an NK-like cell line. Hlx protein levels inversely correlate with those of STAT4, a requisite factor for optimal IFN-γ transcription. Mechanistically, we provide evidence indicating that Hlx overexpression accelerates dephosphorylation and proteasome-dependent degradation of the active Y693-phosphorylated form of STAT4. Thus, Hlx expression in activated NK cells temporally controls and limits the monokine-induced production of IFN-γ, in part through the targeted depletion of STAT4.

Contribution of Natural Killer Cells to Inhibition of Angiogenesis by Interleukin-12

Blood ◽  
1999 ◽  
Vol 93 (5) ◽  
pp. 1612-1621 ◽  
Author(s):  
Lei Yao ◽  
Cecilia Sgadari ◽  
Keizo Furuke ◽  
Eda T. Bloom ◽  
Julie Teruya-Feldstein ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Nk Cells ◽  
Natural Killer ◽  
Cell Function ◽  
Nk Cell ◽  
Primary Cultures ◽  
Interleukin 12 ◽  
Ifn Γ

Interleukin-12 (IL-12) inhibits angiogenesis in vivo by inducing interferon-γ (IFN-γ) and other downstream mediators. Here, we report that neutralization of natural killer (NK) cell function with antibodies to either asialo GM1 or NK 1.1 reversed IL-12 inhibition of basic fibroblast growth factor (bFGF)-induced angiogenesis in athymic mice. By immunohistochemistry, those sites where bFGF-induced neovascularization was inhibited by IL-12 displayed accumulation of NK cells and the presence of IP-10–positive cells. Based on expression of the cytolytic mediators perforin and granzyme B, the NK cells were locally activated. Experimental Burkitt lymphomas treated locally with IL-12 displayed tumor tissue necrosis, vascular damage, and NK-cell infiltration surrounding small vessels. After activation in vitro with IL-12, NK cells from nude mice became strongly cytotoxic for primary cultures of syngeneic aortic endothelial cells. Cytotoxicity was neutralized by antibodies to IFN-γ. These results document that NK cells are required mediators of angiogenesis inhibition by IL-12, and provide evidence that NK-cell cytotoxicity of endothelial cells is a potential mechanism by which IL-12 can suppress neovascularization.

scholarly journals Impairment of Natural Killer Cytotoxic Activity and Interferon γ Production in Ccaat/Enhancer Binding Protein γ–Deficient Mice

1999 ◽  
Vol 190 (11) ◽  
pp. 1573-1582 ◽  
Author(s):  
Tsuneyasu Kaisho ◽  
Hiroko Tsutsui ◽  
Takashi Tanaka ◽  
Tohru Tsujimura ◽  
Kiyoshi Takeda ◽  
...  
Keyword(s):  
Cytotoxic Activity ◽  
Nk Cells ◽  
Natural Killer ◽  
Binding Protein ◽  
Normal Surface ◽  
Enhancer Binding Protein ◽  
Ccaat Enhancer Binding Protein ◽  
Ifn Γ

We have investigated in vivo roles of CCAAT/enhancer binding protein γ (C/EBPγ) by gene targeting. C/EBPγ-deficient (C/EBPγ2/−) mice showed a high mortality rate within 48 h after birth. To analyze the roles of C/EBPγ in lymphoid lineage cells, bone marrow chimeras were established. C/EBPγ2/− chimeras showed normal T and B cell development. However, cytolytic functions of their splenic natural killer (NK) cells after stimulation with cytokines such as interleukin (IL)-12, IL-18, and IL-2 were significantly reduced as compared with those of control chimera NK cells. In addition, the ability of C/EBPγ−/− chimera splenocytes to produce interferon (IFN)-γ in response to IL-12 and/or IL-18 was markedly impaired. NK cells could be generated in vitro with normal surface marker expression in the presence of IL-15 from C/EBPγ2/− newborn spleen cells. However, they also showed lower cytotoxic activity and IFN-γ production when stimulated with IL-12 plus IL-18 than control NK cells, as observed in C/EBPγ2/− chimera splenocytes. In conclusion, our study reveals that C/EBPγ is a critical transcription factor involved in the functional maturation of NK cells.

scholarly journals The PP2A inhibitor SET regulates natural killer cell IFN-γ production

2007 ◽  
Vol 204 (10) ◽  
pp. 2397-2405 ◽  
Author(s):  
Rossana Trotta ◽  
David Ciarlariello ◽  
Jessica Dal Col ◽  
Jeffrey Allard ◽  
Paolo Neviani ◽  
...  
Keyword(s):  
Gene Expression ◽  
Nk Cells ◽  
Natural Killer ◽  
Nk Cell ◽  
Killer Cell ◽  
Immune Surveillance ◽  
Critical Factor ◽  
Interferon Γ ◽  
Pp2a Activity ◽  
Ifn Γ

Monokines (i.e., interleukin [IL]-12, -18, and -15) induce natural killer (NK) cells to produce interferon-γ (IFN-γ), which is a critical factor for immune surveillance of cancer and monocyte clearance of infection. We show that SET, which is a potent inhibitor of protein phosphatase type 2A (PP2A) activity, is highly expressed in human CD56bright NK cells, which produce more IFN-γ than CD56dim NK cells. SET was up-regulated upon monokine stimulation of primary human NK cells. Furthermore, ectopic overexpression of SET significantly enhanced IFN-γ gene expression in monokine-stimulated NK cells. In contrast, RNAi-mediated suppression of SET expression renders NK cells inefficient in producing high levels of IFN-γ in response to monokine costimulation. Mechanistically, suppression of PP2A activity by SET is important for IFN-γ gene expression in NK cells. In fact, treatment of primary human NK cells with the PP2A activator 1,9-dideoxy-forskolin, as well as administration of the drug to C57BL/6 mice, significantly reduced NK-dependent IFN-γ production in response to monokine treatment. Further, SET knockdown or pharmacologic activation of PP2A diminished extracellular signal-regulated kinase 1/2, p65RelA, signal transducer and activator of transduction 4 (STAT4), and STAT5 activity in monokine-stimulated NK cells, potentially contributing to the reduction in IFN-γ gene expression. Thus, SET expression is essential for suppressing PP2A phosphatase activity that would otherwise limit NK cell antitumoral and/or antiinflammatory functions by impairing NK cell production of IFN-γ.

Peroxisome proliferator-activated receptor-γ and its ligands attenuate biologic functions of human natural killer cells

Blood ◽  
2004 ◽  
Vol 104 (10) ◽  
pp. 3276-3284 ◽  
Author(s):  
Xia Zhang ◽  
Maria Cecilia Rodriguez-Galán ◽  
Jeff J. Subleski ◽  
John R. Ortaldo ◽  
Deborah L. Hodge ◽  
...  
Keyword(s):  
Nk Cells ◽  
Natural Killer ◽  
Nk Cell ◽  
Interferon Γ ◽  
Cytolytic Activity ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor ◽  
Protein Levels ◽  
Ppar Γ ◽  
Ifn Γ

Abstract Interferon-γ (IFN-γ) production and cytolytic activity are 2 major biologic functions of natural killer (NK) cells that are important for innate immunity. We demonstrate here that these functions are compromised in human NK cells treated with peroxisome proliferator-activated-γ (PPAR-γ) ligands via both PPAR-γ-dependent and -independent pathways due to variation in PPAR-γ expression. In PPAR-γ-null NK cells, 15-deoxy-Δ12,14 prostaglandin J2 (15d-PGJ2), a natural PPAR-γ ligand, reduces IFN-γ production that can be reversed by MG132 and/or chloroquine, and it inhibits cytolytic activity of NK cells through reduction of both conjugate formation and CD69 expression. In PPARγ-positive NK cells, PPAR-γ activation by 15d-PGJ2 and ciglitazone (a synthetic ligand) leads to reduction in both mRNA and protein levels of IFN-γ. Overexpression of PPAR-γ in PPAR-γ-null NK cells reduces IFN-γ gene expression. However, PPAR-γ expression and activation has no effect on NK cell cytolytic activity. In addition, 15d-PGJ2 but not ciglitazone reduces expression of CD69 in human NK cells, whereas CD44 expression is not affected. These results reveal novel pathways regulating NK cell biologic functions and provide a basis for the design of therapeutic agents that can regulate the function of NK cells within the innate immune response. (Blood. 2004;104:3276-3284)

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