RESUMEN
NFIL3 is a transcription factor that regulates multiple immunologic functions. In myeloid cells, NFIL3 is IL-10 inducible and has a key role as a repressor of IL-12p40 transcription. NFIL3 is a susceptibility gene for the human inflammatory bowel diseases. In this article, we describe spontaneous colitis in Nfil3(-/-) mice. Mice lacking both Nfil3 and Il10 had severe early-onset colitis, suggesting that NFIL3 and IL-10 independently regulate mucosal homeostasis. Lymphocytes were necessary for colitis, because Nfil3/Rag1 double-knockout mice were protected from disease. However, Nfil3/Rag1 double-knockout mice adoptively transferred with wild-type CD4(+) T cells developed severe colitis compared with Rag1(-/-) recipients, suggesting that colitis was linked to defects in innate immune cells. Colitis was abrogated in Nfil3/Il12b double-deficient mice, identifying Il12b dysregulation as a central pathogenic event. Finally, germ-free Nfil3(-/-) mice do not develop colonic inflammation. Thus, NFIL3 is a microbiota-dependent, IL-10-independent regulator of mucosal homeostasis via IL-12p40.
Asunto(s)
Factores de Transcripción con Cremalleras de Leucina de Carácter Básico/metabolismo , Enfermedades Inflamatorias del Intestino/genética , Enfermedades Inflamatorias del Intestino/microbiología , Interleucina-10/genética , Subunidad p40 de la Interleucina-12/metabolismo , Subunidad p19 de la Interleucina-23/metabolismo , Microbiota/inmunología , Traslado Adoptivo , Animales , Proteínas de Arabidopsis/biosíntesis , Factores de Transcripción con Cremalleras de Leucina de Carácter Básico/genética , Células Cultivadas , Colon/inmunología , Colon/patología , Predisposición Genética a la Enfermedad , Subunidad p40 de la Interleucina-12/genética , Subunidad p19 de la Interleucina-23/genética , Proteínas de la Membrana/biosíntesis , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Células TH1/inmunología , Células Th17/inmunología , Factor de Necrosis Tumoral alfa/genéticaRESUMEN
Type 2 T helper (T(H)2) cells are critical for the development of allergic immune responses; however, the molecular mechanism controlling their effector function is still largely unclear. Here, we report that the transcription factor NFIL3/E4BP4 regulates cytokine production and effector function by T(H)2 cells. NFIL3 is highly expressed in T(H)2 cells but much less in T(H)1 cells. Production of interleukin (IL)-13 and IL-5 is significantly increased in Nfil3(-/-) T(H)2 cells and is decreased by expression of NFIL3 in wild-type T(H)2 cells. NFIL3 directly binds to and negatively regulates the Il13 gene. In contrast, IL-4 production is decreased in Nfil3(-/-) T(H)2 cells. Increased IL-13 and IL-5 together with decreased IL-4 production by antigen-stimulated splenocytes from the immunized Nfil3(-/-) mice was also observed. The ability of NFIL3 to alter T(H)2 cytokine production is a T-cell intrinsic effect. Taken together, these data indicate that NFIL3 is a key regulator of T(H)2 responses.
Asunto(s)
Factores de Transcripción con Cremalleras de Leucina de Carácter Básico/metabolismo , Regulación de la Expresión Génica , Interleucina-13/biosíntesis , Interleucina-4/biosíntesis , Interleucina-5/biosíntesis , Células Th2/inmunología , Células Th2/metabolismo , Animales , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Transcripción GenéticaRESUMEN
Antigen presentation by mature dendritic cells (DCs) is the first step for initiating adaptive immune responses. DCs are composed of heterogeneous functional subsets; however, the molecular mechanisms that regulate differentiation of specific DC subsets are not understood. Here, we report that the basic leucine zipper transcription factor NFIL3/E4BP4 is essential for the development of CD8α(+) conventional DCs (cDCs). Nfil3(-/-) mice specifically lack CD8α(+) cDCs but not CD8α(-) cDCs or plasmacytoid DCs in lymphoid tissues. Flt3 ligand-dependent generation of CD8α(+) cDCs in lymphoid tissues and CD8α(+)-equivalent cDCs from Nfil3(-/-) bone marrow cells was also impaired. NFIL3 regulates CD8α(+) cDC development in part through Batf3 expression. Importantly, Nfil3(-/-) mice exhibited impaired cross-priming of CD8(+) T cells against cell-associated antigen, a process normally performed by CD8α(+) cDCs, and failed to produce IL-12 after TLR3 stimulation. Thus, NFIL3 plays an essential role in the development of CD8α(+) cDCs.
Asunto(s)
Factores de Transcripción con Cremalleras de Leucina de Carácter Básico/inmunología , Antígenos CD8/inmunología , Diferenciación Celular/inmunología , Células Dendríticas/inmunología , Células Plasmáticas/inmunología , Animales , Factores de Transcripción con Cremalleras de Leucina de Carácter Básico/biosíntesis , Factores de Transcripción con Cremalleras de Leucina de Carácter Básico/genética , Factores de Transcripción con Cremalleras de Leucina de Carácter Básico/metabolismo , Antígenos CD8/genética , Antígenos CD8/metabolismo , Linfocitos T CD8-positivos/citología , Linfocitos T CD8-positivos/inmunología , Linfocitos T CD8-positivos/metabolismo , Diferenciación Celular/genética , Células Dendríticas/citología , Células Dendríticas/metabolismo , Regulación de la Expresión Génica/genética , Regulación de la Expresión Génica/inmunología , Interleucina-12/genética , Interleucina-12/inmunología , Interleucina-12/metabolismo , Proteínas de la Membrana/genética , Proteínas de la Membrana/inmunología , Proteínas de la Membrana/metabolismo , Ratones , Ratones Noqueados , Células Plasmáticas/citología , Células Plasmáticas/metabolismo , Proteínas Represoras/biosíntesis , Proteínas Represoras/genética , Proteínas Represoras/inmunología , Receptor Toll-Like 3/genética , Receptor Toll-Like 3/inmunología , Receptor Toll-Like 3/metabolismoRESUMEN
Regulation of innate inflammatory responses against the enteric microbiota is essential for the maintenance of intestinal homeostasis. Key participants in innate defenses are macrophages. In these studies, the basic leucine zipper protein, NFIL3, is identified as a regulatory transcription factor in macrophages, controlling IL-12 p40 production induced by bacterial products and the enteric microbiota. Exposure to commensal bacteria and bacterial products induced NFIL3 in cultured macrophages and in vivo. The Il12b promoter has a putative DNA-binding element for NFIL3. Basal and LPS-activated NFIL3 binding to this site was confirmed by chromatin immunoprecipitation. LPS-induced Il12b promoter activity was inhibited by NFIL3 expression and augmented by NFIL3-short hairpin RNA in an Il12b-bacterial artificial chromosome-GFP reporter macrophage line. Il12b inhibition by NFIL3 does not require IL-10 expression, but a C-terminal minimal repression domain is necessary. Furthermore, colonic CD11b(+) lamina propria mononuclear cells from Nfil3(-/-) mice spontaneously expressed Il12b mRNA. Importantly, lower expression of NFIL3 was observed in CD14(+) lamina propria mononuclear cells from Crohn's disease and ulcerative colitis patients compared with control subjects. Likewise, no induction of Nfil3 was observed in colons of colitis-prone Il10(-/-) mice transitioned from germ-free to a conventional microbiota. In conclusion, these experiments characterize NFIL3 as an Il12b transcriptional inhibitor. Interactions of macrophages with the enteric microbiota induce NFIL3 to limit their inflammatory capacity. Furthermore, altered intestinal NFIL3 expression may have implications for the pathogenesis of experimental and human inflammatory bowel diseases.
Asunto(s)
Factores de Transcripción con Cremalleras de Leucina de Carácter Básico/inmunología , Inmunidad Mucosa/inmunología , Subunidad p40 de la Interleucina-12/inmunología , Macrófagos/inmunología , Animales , Secuencia de Bases , Factores de Transcripción con Cremalleras de Leucina de Carácter Básico/genética , Factores de Transcripción con Cremalleras de Leucina de Carácter Básico/metabolismo , Western Blotting , Células Cultivadas , Proteínas Fluorescentes Verdes/genética , Proteínas Fluorescentes Verdes/metabolismo , Humanos , Enfermedades Inflamatorias del Intestino/genética , Enfermedades Inflamatorias del Intestino/inmunología , Enfermedades Inflamatorias del Intestino/metabolismo , Interleucina-10/genética , Interleucina-10/inmunología , Interleucina-10/metabolismo , Subunidad p40 de la Interleucina-12/genética , Subunidad p40 de la Interleucina-12/metabolismo , Lipopolisacáridos/inmunología , Lipopolisacáridos/farmacología , Macrófagos/efectos de los fármacos , Macrófagos/metabolismo , Ratones , Ratones de la Cepa 129 , Ratones Endogámicos C57BL , Ratones Noqueados , Ratones Transgénicos , Microscopía Fluorescente , Datos de Secuencia Molecular , Factor 88 de Diferenciación Mieloide/genética , Factor 88 de Diferenciación Mieloide/inmunología , Factor 88 de Diferenciación Mieloide/metabolismo , Regiones Promotoras Genéticas/genética , Unión Proteica , Interferencia de ARN , Homología de Secuencia de Ácido NucleicoRESUMEN
IL-4 signaling promotes IgE class switching through STAT6 activation and the induction of Ig germ-line epsilon (GLepsilon) transcription. Previously, we and others identified a transcription factor, Nfil3, as a gene induced by IL-4 stimulation in B cells. However, the precise roles of nuclear factor, IL-3-regulated (NFIL3) in IL-4 signaling are unknown. Here, we report that NFIL3 is important for IgE class switching. NFIL3-deficient mice show impaired IgE class switching, and this defect is B-cell intrinsic. The induction of GLepsilon transcripts after LPS and IL-4 stimulation is significantly reduced in NFIL3-deficient B cells. Expression of NFIL3 in NFIL3-deficient B cells restores the impairment of IgE production, and overexpression of NFIL3 in the presence of cycloheximide induces GLepsilon transcripts. Moreover, NFIL3 binds to Iepsilon promoter in vivo. Together, these results identify NFIL3 as a key regulator of IL-4-induced GLepsilon transcription in response to IL-4 and subsequent IgE class switching.
Asunto(s)
Factores de Transcripción con Cremalleras de Leucina de Carácter Básico/fisiología , Inmunoglobulina E/genética , Inmunoglobulina E/inmunología , Región de Cambio de la Inmunoglobulina/genética , Interleucina-4/farmacología , Animales , Linfocitos B/inmunología , Factores de Transcripción con Cremalleras de Leucina de Carácter Básico/deficiencia , Factores de Transcripción con Cremalleras de Leucina de Carácter Básico/genética , Linfocitos T CD4-Positivos/inmunología , Región de Cambio de la Inmunoglobulina/inmunología , Interleucina-4/fisiología , Células Asesinas Naturales/inmunología , Ratones , Ratones Endogámicos BALB C/genética , Ratones Endogámicos C57BL , Ratones NoqueadosRESUMEN
NIDDM is characterized by progressive insulin resistance and the failure of insulin-producing pancreatic beta cells to compensate for this resistance. Hyperinsulinemia, inflammation, and prolonged activation of the insulin receptor (INSR) have been shown to induce insulin resistance by decreasing INSR substrate (IRS) protein levels. Here we describe a role for SOCS7 in regulating insulin signaling. Socs7-deficient mice exhibited lower glucose levels and prolonged hypoglycemia during an insulin tolerance test and increased glucose clearance in a glucose tolerance test. Six-month-old Socs7-deficient mice exhibited increased growth of pancreatic islets with mildly increased fasting insulin levels and hypoglycemia. These defects correlated with increased IRS protein levels and enhanced insulin action in cells lacking SOCS7. Additionally, SOCS7 associated with the INSR and IRS1--molecules that are essential for normal regulation of insulin action. These data suggest that SOCS7 is a potent regulator of glucose homeostasis and insulin signaling.
Asunto(s)
Insulina/metabolismo , Islotes Pancreáticos/metabolismo , Islotes Pancreáticos/patología , Proteínas Nucleares/metabolismo , Transducción de Señal/fisiología , Proteínas Supresoras de la Señalización de Citocinas/metabolismo , Animales , Línea Celular , Diabetes Mellitus Tipo 2/patología , Diabetes Mellitus Tipo 2/fisiopatología , Femenino , Marcación de Gen , Glucosa/metabolismo , Homeostasis , Humanos , Proteínas Sustrato del Receptor de Insulina , Islotes Pancreáticos/citología , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Músculo Esquelético/metabolismo , Proteínas Nucleares/genética , Fosfoproteínas/genética , Fosfoproteínas/metabolismo , ARN Mensajero/metabolismo , Receptor de Insulina/metabolismo , Proteínas Supresoras de la Señalización de Citocinas/genéticaRESUMEN
Regulatory T cells (Tregs) play an important role in preventing both autoimmune and inflammatory diseases. Many recent studies have focused on defining the signal transduction pathways essential for the development and the function of Tregs. Increasing evidence suggest that T-cell receptor (TCR), interleukin-2 (IL-2) receptor (IL-2R), and co-stimulatory receptor signaling are important in the early development, peripheral homeostasis, and function of Tregs. The phosphoinositide-3 kinase (PI3K)-regulated pathway (PIP3 pathway) is one of the major signaling pathways activated upon TCR, IL-2R, and CD28 stimulation, leading to T-cell activation, proliferation, and cell survival. Activation of the PIP3 pathway is also negatively regulated by two phosphatidylinositol phosphatases SHIP and PTEN. Several mouse models deficient for the molecules involved in PIP3 pathway suggest that impairment of PIP3 signaling leads to dysregulation of immune responses and, in some cases, autoimmunity. This review will summarize the current understanding of the importance of the PIP3 pathway in T-cell signaling and the possible roles this pathway performs in the development and the function of Tregs.
Asunto(s)
Autoinmunidad , Fosfatos de Fosfatidilinositol/metabolismo , Receptores de Antígenos de Linfocitos T/metabolismo , Linfocitos T Reguladores/inmunología , Animales , Antígenos CD28/inmunología , Antígenos CD28/metabolismo , Inositol Polifosfato 5-Fosfatasas , Ratones , Fosfohidrolasa PTEN/metabolismo , Fosfatidilinositol 3-Quinasas/genética , Fosfatidilinositol 3-Quinasas/metabolismo , Monoéster Fosfórico Hidrolasas/metabolismo , Receptores de Antígenos de Linfocitos T/inmunología , Receptores de Interleucina-2/inmunología , Receptores de Interleucina-2/metabolismo , Transducción de Señal , Linfocitos T Reguladores/metabolismoRESUMEN
The ST2 gene was originally identified as a primary responsive gene, and the expressions of its gene products are induced by stimulation with growth factors and by oncogenic stresses. In this study, we observed that oncogenic Ras mutant induced the expression of ST2 and ST2L proteins. Interestingly, the enforced expression of ST2 gene products in NIH-3T3 murine fibroblasts remarkably enhanced Ras (G12V)-induced cellular transformation. Furthermore, when the expression of ST2 gene products was silenced by RNA-interference technique, Ras (G12V)-induced cellular transformation was drastically suppressed. According to these observations, it was indicated that the oncogenic Ras-induced expression of ST2 gene products is required for the acceleration of cellular transformation, and this seems to be independent of the stimulation with IL-33, a ligand for ST2/ST2L. Interestingly, knockdown of ST2 gene products caused a reduction in Rb phosphorylation in transformed murine fibroblasts, suggesting the functional involvement of ST2 gene products in cell cycle progression during cellular transformation. Our current study strongly suggests the importance of ST2 gene products in cellular transformation, and the presence of novel mechanism how ST2 gene products affect the cellular transformation and cell proliferation.
RESUMEN
Circadian clocks regulate numerous physiological processes that vary across the day-night (diurnal) cycle, but if and how the circadian clock regulates the adaptive immune system is mostly unclear. Interleukin-17-producing CD4(+) T helper (T(H)17) cells are proinflammatory immune cells that protect against bacterial and fungal infections at mucosal surfaces. Their lineage specification is regulated by the orphan nuclear receptor RORγt. We show that the transcription factor NFIL3 suppresses T(H)17 cell development by directly binding and repressing the Rorγt promoter. NFIL3 links T(H)17 cell development to the circadian clock network through the transcription factor REV-ERBα. Accordingly, TH17 lineage specification varies diurnally and is altered in Rev-erbα(-/-) mice. Light-cycle disruption elevated intestinal T(H)17 cell frequencies and increased susceptibility to inflammatory disease. Thus, lineage specification of a key immune cell is under direct circadian control.
Asunto(s)
Factores de Transcripción con Cremalleras de Leucina de Carácter Básico/metabolismo , Diferenciación Celular/genética , Relojes Circadianos/inmunología , Regulación de la Expresión Génica , Miembro 3 del Grupo F de la Subfamilia 1 de Receptores Nucleares/genética , Células Th17/citología , Animales , Factores de Transcripción con Cremalleras de Leucina de Carácter Básico/genética , Proteínas CLOCK/genética , Linaje de la Célula/genética , Relojes Circadianos/genética , Vida Libre de Gérmenes , Células HEK293 , Humanos , Intestino Delgado/inmunología , Intestino Delgado/microbiología , Células Jurkat , Ratones , Ratones Endogámicos C57BL , Ratones Mutantes , Miembro 1 del Grupo D de la Subfamilia 1 de Receptores Nucleares/genética , Miembro 1 del Grupo D de la Subfamilia 1 de Receptores Nucleares/metabolismo , Regiones Promotoras GenéticasRESUMEN
Suppressors of cytokine signaling 1 and 3 (SOCS-1 and SOCS-3) are inhibitors of the Janus tyrosine kinase (JAK)/signal transducers and activators of transcription (STAT) pathway and function in a negative feedback loop during cytokine signaling. Abl transformation is associated with constitutive activation of JAK/STAT-dependent signaling. However, the mechanism by which Abl oncoproteins bypass SOCS inhibitory regulation remains poorly defined. Here, we demonstrate that coexpression of Bcr-Abl with SOCS-1 or SOCS-3 results in tyrosine phosphorylation of these SOCS proteins. Interestingly, SOCS-1 is highly tyrosine phosphorylated in one of five primary chronic myelogenous leukemia samples. Bcr-Abl-dependent tyrosine phosphorylation of SOCS-1 and SOCS-3 occurs mainly on Tyr 155 and Tyr 204 residues of SOCS-1 and on Tyr 221 residue of SOCS-3. We observed that phosphorylation of these SOCS proteins was associated with their binding to Bcr-Abl. Bcr-Abl-dependent phosphorylation of SOCS-1 and SOCS-3 diminished their inhibitory effects on the activation of JAK and STAT5 and thereby enhanced JAK/STAT5 signaling. Strikingly, disrupting the tyrosine phosphorylation of SOCS-1 or SOCS-3 impaired the expression of Bcl-X(L) protein and sensitized K562 leukemic cells to undergo apoptosis. Moreover, selective mutation of tyrosine phosphorylation sites of SOCS-1 or SOCS-3 significantly blocked Bcr-Abl-mediated tumorigenesis in nude mice and inhibited Bcr-Abl-mediated murine bone marrow transformation. Together, these results reveal a mechanism of how Bcr-Abl may overcome SOCS-1 and SOCS-3 inhibition to constitutively activate the JAK/STAT-dependent signaling, and suggest that Bcr-Abl may critically requires tyrosine phosphorylation of SOCS-1 and SOCS-3 to mediate tumorigenesis when these SOCS proteins are present in cells.
Asunto(s)
Transformación Celular Neoplásica/genética , Transformación Celular Neoplásica/metabolismo , Proteínas de Fusión bcr-abl/genética , Proteínas Supresoras de la Señalización de Citocinas/metabolismo , Animales , Apoptosis , Elonguina , Femenino , Proteínas de Fusión bcr-abl/metabolismo , Expresión Génica , Humanos , Janus Quinasa 1/metabolismo , Janus Quinasa 2/metabolismo , Células K562 , Leucemia Mielógena Crónica BCR-ABL Positiva/genética , Leucemia Mielógena Crónica BCR-ABL Positiva/metabolismo , Ratones , Ratones Desnudos , Mutación , Fosforilación , Unión Proteica , Factores de Transcripción STAT/metabolismo , Transducción de Señal , Proteína 1 Supresora de la Señalización de Citocinas , Proteína 3 Supresora de la Señalización de Citocinas , Proteínas Supresoras de la Señalización de Citocinas/genética , Factores de Transcripción/metabolismo , Tirosina/metabolismoRESUMEN
CD40 is a cell surface receptor important in the activation of antigen-presenting cells during immune responses. In macrophages and dendritic cells, engagement of CD40 by its ligand CD154 provides signals critical for anti-microbial and T cell-mediated immune responses, respectively. In B cells, CD40 signaling has a major role in regulating cell proliferation, antibody production, and memory B cell development. CD40 engagement results in the formation of a receptor-associated complex that mediates activation of NF-κB, stress-activated protein kinases, and other signaling molecules. However, the mechanisms that link CD40 to these signaling events have been only partially characterized. Known components of the CD40 signaling complex include members of the TNF receptor-associated factor (TRAF) family of proteins. We previously showed that the TRAF family member TRAF2 mediates recruitment of HOIL-1L-interacting protein (HOIP) to the cytoplasmic domain of CD40, suggesting that HOIP has a role in the CD40 signaling pathway. To determine the role of HOIP in CD40 signaling, we used somatic cell gene targeting to generate mouse B cell lines deficient in HOIP. We found that the CD40-induced upregulation of CD80 and activation of germline immunoglobulin epsilon transcription were defective in HOIP-deficient cells. We also found that the CD40-mediated activation of NF-κB and c-Jun kinase was impaired. Recruitment of IκB kinase proteins to the CD40 signaling complex was undetectable in HOIP-deficient cells, potentially explaining the defect in NF-κB activation. Restoration of HOIP expression reversed the defects in cellular activation and signaling. These results reveal HOIP as a key component of the CD40 signaling pathway.
Asunto(s)
Antígenos CD40/metabolismo , Ubiquitina-Proteína Ligasas/fisiología , Animales , Antígeno B7-1/metabolismo , Línea Celular , Activación Enzimática , Citometría de Flujo , Marcación de Gen , Células Germinativas , Inmunoprecipitación , MAP Quinasa Quinasa 4/metabolismo , Ratones , FN-kappa B/metabolismo , Retroviridae/genética , Transducción de Señal , Linfocitos T/inmunología , Transducción Genética , Ubiquitina-Proteína Ligasas/genética , Regulación hacia ArribaRESUMEN
The adaptor protein, downstream of tyrosine kinases-1 (Dok-1), and the phosphatase SHIP are both tyrosine phosphorylated in response to T cell stimulation. However, a function for these molecules in T cell development has not been defined. To clarify the role of Dok-1 and SHIP in T cell development in vivo, we compared the T cell phenotype of wild-type, Dok-1 knockout (KO), SHIP KO, and Dok-1/SHIP double-knockout (DKO) mice. Dok-1/SHIP DKO mice were runted and had a shorter life span compared with either Dok-1 KO or SHIP KO mice. Thymocyte numbers from Dok-1/SHIP DKO mice were reduced by 90%. Surface expression of both CD25 and CD69 was elevated on freshly isolated splenic CD4(+) T cells from SHIP KO and Dok-1/SHIP DKO, suggesting these cells were constitutively activated. However, these T cells did not proliferate or produce IL-2 after stimulation. Interestingly, the CD4(+) T cells from SHIP KO and Dok-1/SHIP DKO mice produced higher levels of TGF-beta, expressed Foxp3, and inhibited IL-2 production by CD3-stimulated CD4(+)CD25(-) T cells in vitro. These findings suggest Dok-1 and SHIP function in pathways that influence regulatory T cell development.