ABSTRACT
Deubiquitinases (DUBs) are a new class of drug targets, although the physiological function of only few DUBs has been characterized. Here we identified the DUB USP15 as a crucial negative regulator of T cell activation. USP15 stabilized the E3 ubiquitin ligase MDM2, which in turn negatively regulated T cell activation by targeting the degradation of the transcription factor NFATc2. USP15 deficiency promoted T cell activation in vitro and enhanced T cell responses to bacterial infection and tumor challenge in vivo. USP15 also stabilized MDM2 in cancer cells and regulated p53 function and cancer-cell survival. Our results suggest that inhibition of USP15 may both induce tumor cell apoptosis and boost antitumor T cell responses.
Subject(s)
NFATC Transcription Factors/metabolism , Proto-Oncogene Proteins c-mdm2/immunology , Th1 Cells/immunology , Ubiquitin-Specific Proteases/immunology , Adoptive Transfer , Animals , Apoptosis/immunology , Cell Differentiation/immunology , Cell Line, Tumor , Cell Survival , HCT116 Cells , Humans , Leupeptins/pharmacology , Listeria monocytogenes/immunology , Listeriosis/immunology , Lymphocyte Activation/immunology , Melanoma, Experimental/immunology , Mice , Mice, Inbred C57BL , Mice, Knockout , Proto-Oncogene Proteins c-mdm2/genetics , Tumor Escape , Tumor Suppressor Protein p53/immunology , Ubiquitin-Specific Proteases/genetics , Ubiquitination/genetics , Ubiquitination/immunologyABSTRACT
Glutamine has been implicated as an immunomodulatory nutrient, but how glutamine uptake is mediated during T cell activation is poorly understood. We have shown that naive T cell activation is coupled with rapid glutamine uptake, which depended on the amino acid transporter ASCT2. ASCT2 deficiency impaired the induction of T helper 1 (Th1) and Th17 cells and attenuated inflammatory T cell responses in mouse models of immunity and autoimmunity. Mechanistically, ASCT2 was required for T cell receptor (TCR)-stimulated activation of the metabolic kinase mTORC1. We have further shown that TCR-stimulated glutamine uptake and mTORC1 activation also required a TCR signaling complex composed of the scaffold protein CARMA1, the adaptor molecule BCL10, and the paracaspase MALT1. This function was independent of IKK kinase, a major downstream target of the CARMA1 complex. These findings highlight a mechanism of T cell activation involving ASCT2-dependent integration of the TCR signal and a metabolic signaling pathway.
Subject(s)
Amino Acid Transport System ASC/immunology , Glutamine/metabolism , Multiprotein Complexes/metabolism , Receptors, Antigen, T-Cell/immunology , TOR Serine-Threonine Kinases/metabolism , Adaptor Proteins, Signal Transducing/metabolism , Adoptive Transfer , Amino Acid Transport System ASC/genetics , Amino Acid Transport System ASC/metabolism , Animals , B-Cell CLL-Lymphoma 10 Protein , Biological Transport , CARD Signaling Adaptor Proteins/metabolism , CD28 Antigens/immunology , Caspases/metabolism , Cell Differentiation/immunology , Encephalomyelitis, Autoimmune, Experimental/immunology , Encephalomyelitis, Autoimmune, Experimental/pathology , Enzyme Activation/immunology , Humans , Inflammation/immunology , Interleukin-2/biosynthesis , Jurkat Cells , Leucine/metabolism , Lymphocyte Activation/immunology , Mechanistic Target of Rapamycin Complex 1 , Mice , Mice, Inbred C57BL , Mice, Knockout , Minor Histocompatibility Antigens , Mucosa-Associated Lymphoid Tissue Lymphoma Translocation 1 Protein , Neoplasm Proteins/metabolism , Signal Transduction/immunology , Th1 Cells/immunologyABSTRACT
Intracellular cyclic adenosine monophosphate (cAMP) suppresses innate immunity by inhibiting proinflammatory cytokine production from monocytic cells. Enhanced expression of interleukin-10 (IL-10) has been suggested to be the mechanism of suppression. However, cAMP is still capable of suppressing production of the cytokines TNF-alpha and IL-12 in IL-10-deficient dendritic cells (DCs). Here, we demonstrated that the transcription factor c-Fos was responsible for the cAMP-mediated suppression of inflammatory cytokine production. c-Fos accumulated at high amounts in response to cAMP and lipopolysaccharide (LPS). Overexpression of c-Fos suppressed LPS-induced cytokine production, whereas cAMP-mediated suppression of TNF-alpha and IL-12 was impaired in Fos(-/-) DCs or in RAW264.7 cells treated with c-Fos siRNA. c-Fos physically interacted with p65 protein and reduced the recruitment of p65 to the Tnf promoter. Multiple sites of c-Fos were phosphorylated by the IKKbeta protein. Thus, we propose that c-Fos is a substrate of IKKbeta and is responsible for the immunosuppressive effect of cAMP.
Subject(s)
Cyclic AMP/immunology , Cytokines/metabolism , Gene Expression Regulation , Proto-Oncogene Proteins c-fos/immunology , Animals , Cells, Cultured , Cytokines/antagonists & inhibitors , Dendritic Cells/immunology , Enzyme-Linked Immunosorbent Assay , I-kappa B Kinase/metabolism , Immunity, Innate , Mice , Mice, Knockout , Phosphorylation , Proto-Oncogene Proteins c-fos/classification , Proto-Oncogene Proteins c-fos/genetics , Reverse Transcriptase Polymerase Chain ReactionABSTRACT
Melanoma is the most aggressive skin cancer; its prognosis, particularly in advanced stages, is disappointing largely due to the resistance to conventional anticancer treatments and high metastatic potential. NF-κB constitutive activation is a major factor for the apoptosis resistance of melanoma. Several studies suggest a role for the immunophilin FKBP51 in NF-κB activation, but the underlying mechanism is still unknown. In the present study, we demonstrate that FKBP51 physically interacts with IKK subunits, and facilitates IKK complex assembly. FKBP51-knockdown inhibits the binding of IKKγ to the IKK catalytic subunits, IKK-α and -ß, and attenuates the IKK catalytic activity. Using FK506, an inhibitor of the FKBP51 isomerase activity, we found that the IKK-regulatory role of FKBP51 involves both its scaffold function and its isomerase activity. Moreover, FKBP51 also interacts with TRAF2, an upstream mediator of IKK activation. Interestingly, both FKBP51 TPR and PPIase domains are required for its interaction with TRAF2 and IKKγ, whereas only the TPR domain is involved in interactions with IKKα and ß. Collectively, these results suggest that FKBP51 promotes NF-κB activation by serving as an IKK scaffold as well as an isomerase. Our findings have profound implications for designing novel melanoma therapies based on modulation of FKBP51.
Subject(s)
Melanoma/metabolism , NF-kappa B/metabolism , Tacrolimus Binding Proteins/metabolism , Cell Line, Tumor , Humans , I-kappa B Kinase/metabolism , Melanoma/enzymology , Protein Interaction Domains and Motifs , TNF Receptor-Associated Factor 2/metabolism , Tacrolimus Binding Proteins/chemistryABSTRACT
The noncanonical NF-κB pathway induces processing of the NF-κB2 precursor protein p100, and thereby mediates activation of p52-containing NF-κB complexes. This pathway is crucial for B cell maturation and humoral immunity, but its role in regulating T cell function is less clear. Using mutant mice that express a nonprocessible p100, NF-κB2(lym1), we show that the noncanonical NF-κB pathway has a T cell-intrinsic role in regulating the pathogenesis of a T cell-mediated autoimmunity, experimental autoimmune encephalomyelitis (EAE). Although the lym1 mutation does not interfere with naive T cell activation, it renders the Th17 cells defective in the production of inflammatory effector molecules, particularly the cytokine GM-CSF. We provide evidence that p52 binds to the promoter of the GM-CSF-encoding gene (Csf2) and cooperates with c-Rel in the transactivation of this target gene. Introduction of exogenous p52 or GM-CSF to the NF-κB2(lym1) mutant T cells partially restores their ability to induce EAE. These results suggest that the noncanonical NF-κB pathway mediates induction of EAE by regulating the effector function of inflammatory T cells.
Subject(s)
Encephalomyelitis, Autoimmune, Experimental/immunology , Granulocyte-Macrophage Colony-Stimulating Factor/immunology , NF-kappa B p52 Subunit/immunology , Th17 Cells/immunology , Transcriptional Activation/immunology , Animals , Encephalomyelitis, Autoimmune, Experimental/genetics , Encephalomyelitis, Autoimmune, Experimental/pathology , Granulocyte-Macrophage Colony-Stimulating Factor/genetics , Inflammation/genetics , Inflammation/immunology , Inflammation/pathology , Mice , Mice, Knockout , Mutation , NF-kappa B p52 Subunit/genetics , Proto-Oncogene Proteins c-rel/genetics , Proto-Oncogene Proteins c-rel/immunology , Th17 Cells/pathology , Transcriptional Activation/geneticsABSTRACT
Suppressor of cytokine signaling (SOCS) 3 is a major negative feedback regulator of signal transducer and activator of transcription 3-activating cytokines. Studies using T-cell-specific SOCS3-deficient mice indicate that the absence of SOCS3 in T cells results in exacerbation of disease progression after infection by Leishmania major due to skewing of the T(h)3 cell phenotype accompanied by hyper-production of IL-10 and transforming growth factor ß (TGF-ß). Here we show that transgenic mice over-expressing the SOCS3 gene in T cells (Lck-SOCS3 Tg mice) are also susceptible to infection by L. major. Forced expression of SOCS3 in T cells did not affect the production of the anti-inflammatory cytokines IL-10 and TGF-ß or that of the protective T(h)1 type cytokine IFN-γ, which is required for parasite clearance. CD4(+) T cells isolated from infected-Lck-SOCS3 Tg mice produced much higher levels of IL-4 when they were re-stimulated with L. major antigen in vitro. Exacerbation of disease progression in Lck-SOCS3 Tg mice was completely reversed by administration of a neutralizing antibody against IL-4. These data suggest that tight regulation of SOCS3 expression in T(h) cells is crucial for disease control during infection by L. major.
Subject(s)
Gene Expression , Interleukin-4/immunology , Leishmaniasis, Cutaneous/immunology , Leishmaniasis, Cutaneous/physiopathology , Suppressor of Cytokine Signaling Proteins/metabolism , T-Lymphocytes/immunology , Animals , Cytokines/immunology , Disease Progression , Leishmania major/physiology , Mice , Mice, Inbred C57BL , Mice, Transgenic , Signal Transduction , Suppressor of Cytokine Signaling 3 Protein , Suppressor of Cytokine Signaling Proteins/genetics , T-Lymphocytes, Regulatory/immunology , Time FactorsABSTRACT
Suppressor of cytokine signaling 3 (SOCS3), a negative-feedback molecule for cytokine signaling, has been implicated in protection against liver injury. Previous studies have shown that overexpression of SOCS3 in the liver by adenovirus or membrane permeable recombinant protein protected the liver from various injuries. However it remained uncertain in which type of cells SOCS3 suppresses liver injury. In this study, we demonstrated that forced expression of SOCS3 in T and NKT cells suppressed ConA-induced hepatitis using T and NKT cell-specific SOCS3 transgenic (Lck-SOCS3 Tg) mice. IFN-gamma and IL-4 production was reduced in Lck-SOCS3 Tg mice as well as splenocytes treated with ConA. IFN-gamma and IL-4 levels were also reduced in Lck-SOCS3 Tg mice administrated with alpha-galactosylceramide, suggesting that SOCS3 in NKT cells has suppressive function. Sustained expression of SOCS3 in an NKT cell line also resulted in reduced expression of various cytokines and transcription factors. In contrast, T and NKT cell-specific SOCS3 conditional knockout (Lck-SOCS3 cKO) mice were hypersensitive to ConA-mediated hepatitis. Isolated SOCS3-deficient NKT cells produced higher levels of IFN-gamma and IL-4. These data indicate that SOCS3 plays a negative regulatory role in NKT cell activation and that forced expression of SOCS3 in NKT cells is effective in preventing hepatitis.
Subject(s)
Hepatitis/immunology , Lymphocyte Activation/immunology , Natural Killer T-Cells/immunology , Suppressor of Cytokine Signaling Proteins/immunology , T-Lymphocytes/immunology , Animals , Blotting, Western , Concanavalin A/toxicity , Cytokines/biosynthesis , Enzyme-Linked Immunosorbent Assay , Flow Cytometry , Hepatitis/etiology , Mice , Mice, Transgenic , Mitogens/toxicity , Reverse Transcriptase Polymerase Chain Reaction , Suppressor of Cytokine Signaling 3 ProteinABSTRACT
The membrane microdomains known as lipid rafts have been shown to act as platforms for the initiation of various receptor signals. Through proteomic analysis, we have identified a novel protein termed Raftlin (raft-linking protein) as a major protein in lipid rafts. To determine the physiological and immunological functions of Raftlin in mammals, we generated Raftlin-deficient mice, as well as Raftlin-transgenic (Tg) mice. Although Raftlin was originally identified in B cells, we observe no severe abnormalities in the B cells of these mice, presumably due to a high expression of Raftlin-homologue (Raftlin-2). T cells, in contrast, expressed a substantial amount of Raftlin but no Raftlin-2. In Raftlin-deficient mice, T cell-dependent Ab production was reduced, and experimental autoimmune encephalomyelitis, a Th17-dependent autoimmune disease model, was ameliorated. In Raftlin-Tg mice, in contrast, Ab production was enhanced and experimental autoimmune encephalomyelitis was more severe. Cytokine production, especially that of IL-17, was reduced in Raftlin-deficient T cells, while it was enhanced in Raftlin-Tg T cells. We found that these changes were associated with the strength of the TCR-mediated signals. Importantly, localization of Lck protein in the lipid rafts was enhanced by Raftlin overexpression and reduced by Raftlin deficiency. These data indicate that Raftlin modulates TCR signals and is necessary for the fine-tuning of T cell-mediated immune responses.
Subject(s)
Membrane Microdomains/immunology , Membrane Proteins/immunology , Receptors, Antigen, T-Cell/immunology , Signal Transduction/immunology , T-Lymphocytes, Helper-Inducer/immunology , Animals , Asthma/immunology , Asthma/metabolism , Blotting, Southern , Encephalomyelitis, Autoimmune, Experimental/immunology , Encephalomyelitis, Autoimmune, Experimental/metabolism , Interleukin-17/biosynthesis , Interleukin-17/immunology , Lymphocyte Activation/immunology , Membrane Microdomains/genetics , Membrane Microdomains/metabolism , Membrane Proteins/genetics , Membrane Proteins/metabolism , Mice , Mice, Transgenic , Receptors, Antigen, T-Cell/metabolism , Reverse Transcriptase Polymerase Chain Reaction , T-Lymphocytes, Helper-Inducer/metabolismABSTRACT
UNLABELLED: Acute liver failure is associated with significant mortality. However, the underlying pathophysiological mechanism is not yet fully understood. Suppressor of cytokine signaling-1 (SOCS1), which is a negative-feedback molecule for cytokine signaling, has been shown to be rapidly induced during liver injury. Here, using liver-specific SOCS1-conditional-knockout mice, we demonstrated that SOCS1 deletion in hepatocytes enhanced concanavalin A (ConA)-induced hepatitis, which has been shown to be dependent on activated T and natural killer T (NKT) cells. Although serum cytokine level and NKT cell activation were similar in wild-type (WT) and SOCS1-deficient mice after ConA treatment, proapoptotic signals, including signal transducers and activators of transcription 1 (STAT1) and Jun-terminal kinase (JNK) activation, were enhanced in SOCS1-deficient livers compared with those in WT livers. SOCS1-deficient hepatocytes had higher expression of Fas antigen and were more sensitive to anti-Fas antibody-induced apoptosis than were WT hepatocytes. Furthermore, SOCS1-deficient hepatocytes were more sensitive to tumor necrosis factor (TNF)-alpha-induced JNK activation and apoptosis. These data indicate that SOCS1 is important to the prevention of hepatocyte apoptosis induced by Fas and TNF-alpha. In contrast, SOCS1 overexpression in the liver by adenoviral gene transfer prevented ConA-induced liver injury. CONCLUSION: These findings indicate that SOCS1 plays important negative roles in fulminant hepatitis and that forced expression of SOCS1 is therapeutic in preventing hepatitis.
Subject(s)
Apoptosis/drug effects , Concanavalin A/toxicity , Hepatitis, Animal/chemically induced , Hepatitis, Animal/prevention & control , Liver/pathology , Suppressor of Cytokine Signaling Proteins/genetics , Acute Disease , Animals , Disease Models, Animal , Enzyme-Linked Immunosorbent Assay , Flow Cytometry , Hepatitis, Animal/pathology , Liver/drug effects , Liver Failure/prevention & control , Lymphocytes/cytology , Mice , Mice, Inbred C57BL , Mice, Knockout , RNA/genetics , RNA/isolation & purification , Reverse Transcriptase Polymerase Chain Reaction , Suppressor of Cytokine Signaling 1 Protein , Suppressor of Cytokine Signaling Proteins/deficiencyABSTRACT
Estrogens have diverse effects on cell growth, differentiation and homeostatic functions, and have been shown to play an important role in regulating immune system. In this study, we examined the effect of 17beta-estradiol (E2) on antibody production by splenocytes isolated from C57BL/6N mice. Our results suggest that the activation of immunoglobulin (Ig) M production by E2 requires direct cell-cell interaction between adherent and non-adherent cells in mouse splenocyte population, and the primary target of E2 is adherent cell population. In addition, we indicated that ER antagonist ICI 182780 suppressed this enhancing effect of E2. Both ERalpha agonist and ERalpha agonist enhanced IgM production of mouse splenocytes. ERs are expressed on plasma membrane as well as in nucleus. However, a plasma membrane-associated ER specific ligand has no stimulation effect on IgM production. In conclusion, our results indicate that adherent cells stimulated by E2 up-regulate IgM production of lymphocytes through the direct cell-cell interactions, and the enhancing effect of E2 is arouse through ERalpha and ERbeta on these cells.
Subject(s)
Estrogens/pharmacology , Immunoglobulin M/biosynthesis , Lymphocytes/drug effects , Lymphocytes/immunology , Spleen/cytology , Spleen/drug effects , Animals , Cell Adhesion , Cells, Cultured , Estradiol/pharmacology , Lymphocytes/metabolism , Male , Mice , Mice, Inbred C57BL , Receptors, Estrogen/metabolism , Spleen/immunologyABSTRACT
Isoflavones, such as genistein and daidzein, are found in abundance in soybeans. These plant-derived substances have estrogenic activities and can bind to the estrogen receptors (ERs). In this study, we investigated that the effects of 17beta-estradiol (E2), genistein and daidzein on nitric oxide (NO) production and inducible nitric oxide synthase (iNOS) activity in RAW264.7 cells. We found that these isoflavones significantly increased lipopolysaccharide-induced NO production and iNOS expression as much as E2 at physiological concentrations. Moreover, E2 and isoflavone enhanced the production of tumor necrosis factor-alpha that is one of the important cytokines regarding NO production. The enhancing effects of E2 and isoflavones on NO production were markedly inhibited by not only N(G)-nitro-L-arginine methyl ester (an inhibitor of NOS), but also ICI 182780 (ERs antagonist). Two types of ERs were identified as ERalpha and ERbeta. An ERalpha agonist could increase iNOS expression in RAW264.7 cells, while an ERbeta agonist could not. In conclusion, our results suggest E2, genistein and daidzein activate iNOS, and then up-regulate NO production. This enhancing effect is aroused through ERalpha pathway in RAW264.7 cells.
Subject(s)
Genistein/pharmacology , Isoflavones/pharmacology , Lipopolysaccharides/pharmacology , Nitric Oxide Synthase Type II/metabolism , Receptors, Estrogen/metabolism , Up-Regulation/drug effects , Animals , Base Sequence , Blotting, Western , Cell Line , DNA Primers , Enzyme Activation , Estradiol/pharmacology , Macrophages/drug effects , Macrophages/enzymology , Macrophages/metabolism , Mice , Nitric Oxide/biosynthesis , Reverse Transcriptase Polymerase Chain Reaction , Tumor Necrosis Factor-alpha/biosynthesisABSTRACT
Development of an immune or autoimmune response involves T-cell activation in lymphoid organs and subsequent migration to peripheral tissues. Here we show that T-cell-specific ablation of the kinase TBK1 promotes T-cell activation but causes retention of effector T cells in the draining lymph node in a neuroinflammatory autoimmunity model, experimental autoimmune encephalomyelitis (EAE). At older ages, the T-cell-conditional TBK1-knockout mice also spontaneously accumulate T cells with activated phenotype. TBK1 controls the activation of AKT and its downstream kinase mTORC1 by a mechanism involving TBK1-stimulated AKT ubiquitination and degradation. The deregulated AKT-mTORC1 signalling in turn contributes to enhanced T-cell activation and impaired effector T-cell egress from draining lymph nodes. Treatment of mice with a small-molecule inhibitor of TBK1 inhibits EAE induction. These results suggest a role for TBK1 in regulating T-cell migration and establish TBK1 as a regulator of the AKT-mTORC1 signalling axis.
Subject(s)
Gene Expression Regulation , Lymphocyte Activation/immunology , Protein Serine-Threonine Kinases/metabolism , T-Lymphocytes/cytology , Animals , Autoimmunity/immunology , CD4-Positive T-Lymphocytes/cytology , CD8-Positive T-Lymphocytes/cytology , Cell Movement , Cell Separation , Central Nervous System/metabolism , Encephalomyelitis, Autoimmune, Experimental/genetics , Female , Humans , Jurkat Cells , Macrophages/metabolism , Male , Mechanistic Target of Rapamycin Complex 1 , Mice , Mice, Inbred C57BL , Mice, Knockout , Multiprotein Complexes/metabolism , Orthomyxoviridae , Phenotype , Phosphorylation , Signal Transduction , TOR Serine-Threonine Kinases/metabolismABSTRACT
Here, we reported the effects of 17beta-estradiol (E2), isoflavone genistein (Gen), and daidzein (Dai) on the production of interferon (IFN)-gamma by splenocytes isolated from C57BL/6N mice. When mouse splenocytes were stimulated with lipopolysaccharide, E2, Gen, and Dai suppressed the production of IFN-gamma. However, when only nonadherent cell populations of splenocytes were tested, none of these estrogenic compounds suppressed IFN-gamma production. This result indicates that IFN-gamma production by nonadherent cell populations of splenocytes treated with estrogens is regulated by adherent cell populations. Moreover, direct cell-cell interaction between both populations was necessary for suppression of IFN-gamma production by nonadherent populations. In addition, E2 conjugated with bovine serum albumin inhibited IFN-gamma production as well as E2. This result suggests that the plasma membrane-associated estrogen receptor plays a prominent role in this suppression mechanism.
Subject(s)
Cell Communication/physiology , Estradiol/analogs & derivatives , Estrogens/pharmacology , Interferon-gamma/metabolism , Spleen/cytology , Spleen/drug effects , Animals , Cattle , Cell Adhesion/physiology , Cells, Cultured , Estradiol/pharmacology , Estrogen Antagonists/pharmacology , Fulvestrant , Genistein/metabolism , Isoflavones/metabolism , Male , Mice , Mice, Inbred C57BL , Receptors, Estrogen/metabolismABSTRACT
Previous studies have shown the physiological significance of dietary conjugated linoleic acid (CLA) in various experimental animals and in human beings. One of the important problems to better elucidate is the difference between triglyceride (TG) and free (FFA) dietary CLA. Here, using splenocytes, this study assesses how TG- and FFA-CLA modulate immunoglobulin and various cytokine productions. In this study, C57BL/6N mice were fed an experimental diet containing 0% CLA, 0.1 or 1% FFA-CLA, or 0.1 or 1% TG-CLA for 3 weeks. The production of immunoglobulin tended to be up-regulated by 1% FFA-CLA. As a result of protein array analysis using the supernatant from splenocytes cultured with no CLA, 1% FFA-CLA, and TG-CLA, some cytokine production was shown to be remarkably regulated by dietary FFA- and TG-CLA. A total of 32 cytokines were examined, and 11-14 produced cytokines that were 2-fold up-regulated as compared with control for FFA- or TG-CLA, respectively. Especially, the production of IL-9 and MCP-5 and other cytokines was remarkably up-regulated by both FFA- and TG-CLA. In addition, seven cytokines were 2-fold down-regulated by TG-CLA. These data show that there is a slight but significant difference between the functionalities of FFA- and TG-CLA.
Subject(s)
Immunity , Linoleic Acids, Conjugated/physiology , Triglycerides/physiology , Animals , Cells, Cultured , Cytokines/biosynthesis , Dietary Fats/administration & dosage , Immunoglobulins/biosynthesis , Linoleic Acids, Conjugated/pharmacology , Male , Mice , Mice, Inbred C57BL , Organ Size , Spleen/drug effects , Spleen/immunology , Triglycerides/pharmacology , Weight GainABSTRACT
Development of autoimmune diseases, such as multiple sclerosis and experimental autoimmune encephalomyelitis (EAE), involves the inflammatory action of Th1 and Th17 cells, but the underlying signaling mechanism is incompletely understood. We show that the kinase TPL2 is a crucial mediator of EAE and is required for the pathological action of Th17 cells. TPL2 serves as a master kinase mediating the activation of multiple downstream pathways stimulated by the Th17 signature cytokine IL-17. TPL2 acts by linking the IL-17 receptor signal to the activation of TAK1, which involves a dynamic mechanism of TPL2-TAK1 interaction and TPL2-mediated phosphorylation and catalytic activation of TAK1. These results suggest that TPL2 mediates TAK1 axis of IL-17 signaling, thereby promoting autoimmune neuroinflammation.
Subject(s)
Autoimmunity/immunology , Inflammation/immunology , Inflammation/pathology , Interleukin-17/metabolism , MAP Kinase Kinase Kinases/metabolism , Proto-Oncogene Proteins/metabolism , Signal Transduction/immunology , Animals , Cell Differentiation/immunology , Cell Line , Central Nervous System/pathology , Encephalomyelitis, Autoimmune, Experimental/etiology , Encephalomyelitis, Autoimmune, Experimental/immunology , Encephalomyelitis, Autoimmune, Experimental/pathology , Enzyme Activation , Extracellular Signal-Regulated MAP Kinases/metabolism , Gene Expression Regulation , Hematopoietic System/pathology , Humans , Lymphocyte Activation/immunology , MAP Kinase Kinase Kinases/deficiency , Mice, Knockout , Phosphorylation , Protein Binding , Proto-Oncogene Proteins/deficiency , Radiation Tolerance , Th17 Cells/immunologyABSTRACT
A variety of reactive organic compounds, called haptens, can cause allergic contact dermatitis. However, the innate immune mechanisms by which haptens stimulate dendritic cells (DCs) to sensitize T cells remain unclear. Here we show that the coupling of ITAM-Syk-CARD9 signalling to interleukin-1 (IL-1) secretion in DCs is crucial for allergic sensitization to haptens. Both MyD88 and Caspase recruitment domain-containing protein 9 (CARD9) signalling are required for contact hypersensitivity (CHS). Naïve T cells require signals received through IL-1R1-MyD88 for effector differentiation, whereas DCs require CARD9 and spleen tyrosine kinase (Syk) signalling for hapten-induced IL-1α/ß secretion and their ability to prime T cells. DC-specific deletion of CARD9, DAP12, Syk or NLRP3, but not MyD88, is sufficient to abolish CHS. All tested haptens, but not irritants, can induce Syk activation, leading to both the CARD9/BCL10-dependent pro-IL-1 synthesis (signal1) and reactive oxygen species-mediated NLRP3 inflammasome activation (signal2), required for IL-1 secretion. These data unveil an innate immune mechanism crucial for allergic contact sensitization to chemical compounds.
Subject(s)
CARD Signaling Adaptor Proteins/immunology , Dermatitis, Contact/immunology , Immunoreceptor Tyrosine-Based Activation Motif/immunology , Interleukin-1/biosynthesis , Intracellular Signaling Peptides and Proteins/immunology , Protein-Tyrosine Kinases/immunology , Adaptor Proteins, Signal Transducing/genetics , Adaptor Proteins, Signal Transducing/immunology , Animals , B-Cell CLL-Lymphoma 10 Protein , CARD Signaling Adaptor Proteins/genetics , CD8-Positive T-Lymphocytes/immunology , Carrier Proteins/genetics , Caspase 1/metabolism , Dendritic Cells/immunology , Enzyme Activation/immunology , Inflammasomes/immunology , Interleukin-1/metabolism , Intracellular Signaling Peptides and Proteins/genetics , Mice , Mice, Inbred BALB C , Mice, Inbred C57BL , Mice, Knockout , Myeloid Differentiation Factor 88/genetics , Myeloid Differentiation Factor 88/immunology , NLR Family, Pyrin Domain-Containing 3 Protein , Protein-Tyrosine Kinases/genetics , Reactive Oxygen Species/immunology , Receptors, Interleukin-1 Type I/antagonists & inhibitors , Receptors, Interleukin-1 Type I/immunology , Signal Transduction/genetics , Signal Transduction/immunology , Syk KinaseABSTRACT
The nuclear factor-κB (NF-κB) plays a central role in the activation and survival of lymphocytes. NF-κB, therefore, is pivotal for acquired immunity, but the dysregulation of NF-κB signaling leads to inflammatory diseases and lymphomagenesis. Accumulating evidence has demonstrated that the mucosa-associated lymphoid tissue (MALT) lymphoma-related molecules, B-cell lymphoma 10 (BCL10) and MALT-lymphoma-translocation gene1 (MALT1), are essential signaling components for NF-κB and mitogen-activated protein kinase (MAPK) activation, mediated by the immunoreceptor tyrosine-based activation motif (ITAM)-coupled receptors involved in both innate and adaptive immunity. CARMA1 (also referred to as CARD11 and Bimp3) is a crucial regulator for ITAM-mediated signaling as it forms a complex with BCL10-MALT1 in lymphoid lineage cells such as T, B, natural killer (NK), and natural killer T (NKT) cells, known as the lymphoid CARMA1-BCL10-MALT1 (L-CBM) complex. In this review, recent understanding of the molecular and biological functions and the signal regulation mechanisms of the L-CBM complex are described and its role in disease development and potential as a therapeutic target is further discussed.
ABSTRACT
Cytokine-mediated immunity plays a crucial role in the pathogenesis of various diseases including infection and autoimmune diseases. IL-27, along with IL-12, -23, and -35, belongs to the IL-12 cytokine family. These family members play roles in regulation of Th cell differentiation. IL-27 is unique in that although it induces Th1 differentiation, the same cytokine suppresses immune responses. In the absence of IL-27-mediated immunosuppression, hyperproduction of various proinflammatory cytokines concomitant with severe inflammation is observed. The immunosuppressive effects of IL-27 depend on IL-2 suppression, inhibition of Th17 development, and induction of IL-10 production. Administration of IL-27 suppresses some diseases of autoimmune or allergic origin, demonstrating its potential in therapy of diseases mediated by inflammatory cytokines. In this review, we discuss recent studies about the role of IL-27 in immune regulation in view of its pro- and anti-inflammatory properties and possible therapeutic application.
Subject(s)
Cell Differentiation/immunology , Immune Tolerance , Interleukins/immunology , T-Lymphocytes, Helper-Inducer/immunology , Animals , Autoimmune Diseases/drug therapy , Autoimmune Diseases/immunology , Cytokines/immunology , Humans , Hypersensitivity/drug therapy , Hypersensitivity/immunology , Inflammation/drug therapy , Inflammation/immunology , Interleukins/therapeutic useABSTRACT
The cytokine, transforming growth factor-beta1 (TGF-beta1), converts naive T cells into regulatory T cells that prevent autoimmunity. However, in the presence of interleukin (IL)-6, TGF-beta1 has also been found to promote differentiation into IL-17-producing helper T (Th17) cells that are deeply involved in autoimmunity and inflammation. However, it has not been clarified how TGF-beta1 and IL-6 determine such a distinct fate. Here we found that a master regulator for Th17, retinoic acid-related orphan receptor gammat (RORgammat), was rapidly induced by TGF-beta1 regardless of the presence of IL-6. IL-6 reduced Foxp3 expression, and overexpression of Foxp3 in a T cell line resulted in a strong reduction of IL-17A expression. We have characterized the IL-17A promoter and found that RORgammat binding is sufficient for activation of the minimum promoter in the HEK 293T cells. RORgammat-mediated IL-17A promoter activation was suppressed by forced expression of Foxp3. Foxp3 directly interacted with RORgammat through exon 2 region of Foxp3. The exon 2 region and forkhead (FKH) domain of Foxp3 were necessary for the suppression of RORgammat-mediated IL-17A promoter activation. We propose that induction of Foxp3 is the mechanism for the suppression of Th17 and polarization into inducible Treg.
Subject(s)
Forkhead Transcription Factors/metabolism , Interleukin-17/chemistry , Receptors, Retinoic Acid/chemistry , Receptors, Thyroid Hormone/chemistry , Transcription, Genetic , Animals , Base Sequence , Binding Sites , Humans , Mice , Models, Biological , Molecular Sequence Data , Nuclear Receptor Subfamily 1, Group F, Member 3 , Promoter Regions, Genetic , Protein Binding , Sequence Homology, Nucleic Acid , T-Lymphocytes/metabolismABSTRACT
Royal jelly is known as a functional food containing many useful minerals. In this study, we found an anti-environmental estrogen activity of royal jelly. Bisphenol A (BPA) is an environmental estrogen that stimulates proliferation of human breast cancer MCF-7 cells. Royal jelly inhibited the growth-promoting effect of BPA on MCF-7 cells, even though it did not affect the proliferation of cells in the absence of BPA. In addition, this inhibiting effect of royal jelly was heat-stable.