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ABSTRACT: Atopic dermatitis (AD) is a common pruritic inflammatory disease triggered by a defective skin barrier and immunodysregulation. AD has been considered a typical example of a Th2 response associated with allergic disease. In the early phases of the disease, symptoms include IgE hyperproduction, eosinophil accumulation, and mast cell activation; in the chronic phase, a Th1-dominant immune response is also observed at the sites of AD skin lesions. The role of IL-17-producing Th (Th17) cells in AD has not been established. In the current study, we found that pyridone 6 (P6), a pan-JAK inhibitor, delayed the onset and reduced the magnitude of skin disease in an AD-like skin-disease model of NC/Nga mice. P6 reduced IFN-γ and IL-13, whereas it enhanced IL-17 and IL-22 expression. In vitro, P6 also inhibited both Th1 and Th2 development, whereas it promoted Th17 differentiation from naive T cells when present within a certain range of concentrations. This was probably because P6 strongly inhibited STAT1, STAT5, and STAT6 phosphorylation, whereas STAT3 phosphorylation was less efficiently suppressed by P6 at the same concentration. Furthermore, IL-22 protects keratinocytes from apoptosis induced by IFN-γ, and administration of IL-17 and IL-22 partially ameliorated skin diseases in NC/Nga mice. These results suggested that the JAK inhibitor P6 is therapeutic for AD by modulating the balance of Th2 and Th17.
The Journal of Immunology 09/2011; 187(9):4611-20. · 5.79 Impact Factor
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ABSTRACT: Regulatory T cells (T(reg) cells) maintain immune homeostasis by limiting inflammatory responses. SOCS1 (suppressor of cytokine signaling 1), a negative regulator of cytokine signaling, is necessary for the suppressor functions of T(reg) cells in vivo, yet detailed mechanisms remain to be clarified. We found that Socs1(-/-) T(reg) cells produced high levels of IFN-γ and rapidly lost Foxp3 when transferred into Rag2(-/-) mice or cultured in vitro, even though the CNS2 (conserved noncoding DNA sequence 2) in the Foxp3 enhancer region was fully demethylated. Socs1(-/-) T(reg) cells showed hyperactivation of STAT1 and STAT3. Because Foxp3 expression was stable and STAT1 activation was at normal levels in Ifnγ(-/-)Socs1(-/-) T(reg) cells, the restriction of IFN-γ-STAT1 signaling by SOCS1 is suggested to be necessary for stable Foxp3 expression. However, Ifnγ(-/-)Socs1(-/-) T(reg) cells had hyperactivated STAT3 and higher IL-17A (IL-17) production compared with Ifnγ(-/-)Socs1(+/+) T(reg) cells and could not suppress colitis induced by naive T cells in Rag2(-/-) mice. In vitro experiments suggested that cytokines produced by Socs1(-/-) T(reg) cells and Ifnγ(-/-)Socs1(-/-) T(reg) cells modulated antigen-presenting cells for preferential Th1 and Th17 induction, respectively. We propose that SOCS1 plays important roles in T(reg) cell integrity and function by maintaining Foxp3 expression and by suppressing IFN-γ and IL-17 production driven by STAT1 and STAT3, respectively.
Journal of Experimental Medicine 09/2011; 208(10):2055-67. · 13.85 Impact Factor
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Yu Wakabayashi, Taiga Tamiya,
Ichiro Takada,
Tomohiro Fukaya,
Yuki Sugiyama,
Naoko Inoue,
Akihiro Kimura,
Rimpei Morita,
Ikko Kashiwagi,
Tomohito Takimoto,
Masatoshi Nomura,
Akihiko Yoshimura
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ABSTRACT: Suppression of IL-2 βproduction from T cells is an important process for the immune regulation by TGF-β. However, the mechanism by which this suppression occurs remains to be established. Here, we demonstrate that Smad2 and Smad3, two major TGF-β-downstream transcription factors, are redundantly essential for TGF-β-mediated suppression of IL-2 production in CD4(+) T cells using Smad2- and Smad3-deficient T cells. Both Smad2 and Smad3 were recruited into the proximal region of the IL-2 promoter in response to TGF-β. We then investigated the histone methylation status of the IL-2 promoter. Although both histone H3 lysine 9 (H3K9) and H3K27 trimethylation have been implicated in gene silencing, only H3K9 trimethylation was increased in the proximal region of the IL-2 promoter in a Smad2/3-dependent manner, whereas H3K27 trimethylation was not. The H3K9 methyltransferases Setdb1 and Suv39h1 bound to Smad3 and suppressed IL-2 promoter activity in collaboration with Smad3. Overexpression of Suv39h1 in 68-41 T cells strongly inhibited IL-2 production in response to T cell receptor stimulation irrespective of the presence or absence of TGF-β, whereas Setdb1 overexpression only slightly suppressed IL-2 production. Silencing of Suv39h1 by shRNA reverted the suppressive effect of TGF-β on IL-2 production. Furthermore, TGF-β induced Suv39h1 recruitment to the proximal region of the IL-2 promoter in wild type primary T cells; however, this was not observed in Smad2(-/-)Smad3(+/-) T cells. Thus, we propose that Smads recruit H3K9 methyltransferases Suv39h1 to the IL-2 promoter, thereby inducing suppressive histone methylation and inhibiting T cell receptor-mediated IL-2 transcription.
Journal of Biological Chemistry 08/2011; 286(41):35456-65. · 4.77 Impact Factor
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Yu Wakabayashi, Taiga Tamiya,
Ichiro Takada,
Tomoaki Fukaya,
Yuki Sugiyama,
Naoko Inoue,
Akihiro Kimura,
Rimpei Morita,
Ikko Kashiwagi,
Tomohito Takimoto,
Masatoshi Nomura,
Akihiko Yoshimura
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ABSTRACT: Suppression of interleukin-2 (IL-2) production from T cells is an important process for the immune regulation by transforming
growth factor-beta (TGF-β). However, the mechanism by which this suppression occurs remains to be established. Here, we demonstrate
that Smad2 and Smad3, two major TGF-β-downstream transcription factors, are redundantly essential for TGF-β-mediated suppression
of IL-2 production in CD4+ T cells using Smad2- and Smad3-deficient T cells. Both Smad2 and Smad3 were recruited into the
proximal region of the IL-2 promoter in response to TGF-β. We then investigated the histone methylation status of the IL-2
promoter. Although both histone H3-lysine 9 (H3K9) and H3K27 trimethylation have been implicated in gene silencing, only H3K9
trimethylation was increased in the proximal region of the IL-2 promoter in a Smad2/3-dependent manner, while H3K27 trimethylation
was not. The H3K9 methyltransferases Setdb1 and Suv39h1 bound to Smad3 and suppressed IL-2 promoter activity in collaboration
with Smad3. Overexpression of Suv39h1 in 68-41 T cells strongly inhibited IL-2 production in response to TCR stimulation irrespective
of the presence or absence of TGF-β, while Setdb1 overexpression only slightly suppressed IL-2 production. Silencing of Suv39h1
by shRNA reverted the suppressive effect of TGF-β on IL-2 production. Furthermore, TGF-β induced Suv39h1 recruitment to the
proximal region of the IL-2 promoter in wild type primary T cells, however, this was not observed in Smad2-/-Smad3+/- T cells.
Thus, we propose that Smads recruit H3K9 methyltransferases Suv39h1 to the IL-2 promoter, thereby inducing suppressive histone
methylation and inhibiting TCR-mediated IL-2 transcription.
Journal of Biological Chemistry 08/2011; · 4.77 Impact Factor
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ABSTRACT: The protein known as Spred1 (Sprouty-related Ena/VASP homology-1 domain-containing protein) has been identified as a negative regulator of growth factor-induced ERK/mitogen-activated protein kinase activation. Spred1 has also been implicated as the target of microRNA-126 (miR126), a miRNA located within the Egfl7 gene, and is involved in the regulation of vessel development through its role in regulating VEGF signaling. In this study, we examined the role of miR126 and Spred1 in the hematopoietic system, as miR126 has been shown to be overexpressed in leukemic cells. miR126 levels were down-regulated during mast cell differentiation from bone marrow cells, whereas Spred1 expression was inversely up-regulated. Overexpression of miR126 suppressed Spred1 expression and enhanced ERK activity in primary bone marrow cells and MC9 mast cells, which were associated with elevated FcεRI-mediated cytokine production. To confirm the effect of Spred1 reduction in vivo, we generated hematopoietic cell-specific Spred1-conditional knockout mice. These mice showed increased numbers of mast cells, and Spred1-deficient bone marrow-derived mast cells were highly activated by cross-linking of Fcε-R stimulation as well as by IL-3 and SCF stimulation. These results suggest that Spred1 negatively regulates mast cell activation, which is modulated by miR126.
Genes to Cells 07/2011; 16(7):803-14. · 2.68 Impact Factor
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Kiyokazu Hiwatashi, Taiga Tamiya,
Eiichi Hasegawa,
Tomohiro Fukaya,
Masayuki Hashimoto,
Kyosuke Kakoi,
Ikko Kashiwagi,
Akihiro Kimura,
Naoko Inoue,
Rimpei Morita,
Hideo Yasukawa,
Akihiko Yoshimura
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ABSTRACT: Inflammation has been demonstrated to play important roles in tumorigenesis, tumor progression, and metastasis. STAT3 has been shown to be frequently activated in a variety of human cancer cells and STAT3 signaling promotes the growth and survival of tumor cells. However, the role of STAT3 of myeloid cells associated with tumors is currently unknown. Suppressor of cytokine signaling-3 (SOCS3) has been shown to be a negative regulator of STAT3. In this study, we used macrophage specific SOCS3 conditional knockout (cKO) mice to investigate the effect of the hyperactivation of STAT3 in macrophages on tumor development and metastasis. In a subcutaneous transplantation model of B16F10 melanoma cells, although tumor sizes were not significantly different, SOCS3-cKO mice survived longer than wild-type (WT) mice did. SOCS3-cKO mice exhibited fewer lung and liver metastatic tumor nodules than WT mice when B16F10 was challenged intravenously. SOCS3(-/-) macrophages stimulated with tumor lysates in vitro exhibited prolonged STAT3 phosphorylation and produced less amount of TNFα and IL-6, and higher amount of MCP2/CCL8 than WT macrophages. MCP/CCL8 was induced via STAT3 and exhibited anti-tumor metastatic effect in WT mice. These data suggest that hyperactivation of STAT3 in myeloid cells simultaneously exerted an anti-inflammatory as well as anti-tumor effects. Thus, the targeted inhibition of SOCS3 activity in macrophages may be therapeutic for the suppression of tumor metastasis.
Cancer letters 05/2011; 308(2):172-80. · 4.86 Impact Factor
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Kenji Ichiyama,
Takashi Sekiya,
Naoko Inoue, Taiga Tamiya,
Ikko Kashiwagi,
Akihiro Kimura,
Rimpei Morita,
Go Muto,
Takashi Shichita,
Reiko Takahashi,
Akihiko Yoshimura
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ABSTRACT: Transforming growth factor-β (TGF-β) has been shown to be required for Th17 cell differentiation via Smad-independent mechanisms. The molecular mechanism underlying this pathway remains to be clarified, however. We searched for genes regulated by TGF-β through the Smad-independent pathway by using Smad2 and Smad3 double-deficient T cells and identified the transcription factor Eomesodermin (Eomes), whose expression was suppressed by TGF-β via the c-Jun N-terminal kinase (JNK)-c-Jun signaling pathway. Inhibition of JNK strongly suppressed disease in an in vivo EAE model as well as in vitro Th17 cell induction. Overexpression of Eomes substantially suppressed Th17 cell differentiation, whereas ablation of Eomes expression could substitute for TGF-β in Th17 cell induction in primary T cells. Eomes suppressed Rorc and Il17a promoters by directly binding to the proximal region of these promoters. In conclusion, the suppression of Eomes by TGF-β via the JNK pathway is an important mechanism for Smad-independent Th17 cell differentiation.
Immunity 05/2011; 34(5):741-54. · 21.64 Impact Factor
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ABSTRACT: Various cytokines are involved in the regulation of the immune system and inflammation. Dysregulation of cytokine signaling can cause a variety of diseases, including allergy, autoimmune diseases, inflammation, and cancer. Most cytokines use the so-called janus kinase/signal transducer and activator of transcription pathway, and this pathway is negatively regulated by suppressors of cytokine signaling (SOCS) proteins. SOCS proteins bind to janus kinase and to certain cytokine receptors and signaling molecules, thereby suppressing further signaling events. Studies have shown that SOCS proteins are key physiological regulators of inflammation. Recent studies have also demonstrated that SOCS1 and SOCS3 are important regulators of adaptive immunity.
Arteriosclerosis Thrombosis and Vascular Biology 05/2011; 31(5):980-5. · 6.37 Impact Factor
