RESUMO
Aims: The cytokine interleukin-6 (IL-6) plays a central role in the inflammation cascade as well as cardiovascular disease progression. Since myeloid cells are a primary source of IL-6 formation, we aimed to generate a mouse model to study the role of myeloid cell-derived IL-6 in vascular disease. Methods and results: Interleukin-6-overexpressing (IL-6OE) mice were generated and crossed with LysM-Cre mice, to generate mice (LysM-IL-6OE mice) overexpressing the cytokine in myeloid cells. Eight- to 12-week-old LysM-IL-6OE mice spontaneously developed inflammatory colitis and significantly impaired endothelium-dependent aortic relaxation, increased aortic reactive oxygen species (ROS) formation, and vascular dysfunction in resistance vessels. The latter phenotype was associated with decreased survival. Vascular dysfunction was accompanied by a significant accumulation of neutrophils, monocytes, and macrophages in the aorta, increased myeloid cell reactivity (elevated ROS production), and vascular fibrosis associated with phenotypic changes in vascular smooth muscle cells. In addition to elevated Mcp1 and Cxcl1 mRNA levels, aortae from LysM-IL-6OE mice expressed higher levels of inducible NO synthase and endothelin-1, thus partially accounting for vascular dysfunction, whereas systemic blood pressure alterations were not observed. Bone marrow (BM) transplantation experiments revealed that vascular dysfunction and ROS formation were driven by BM cell-derived IL-6 in a dose-dependent manner. Conclusion: Mice with conditional overexpression of IL-6 in myeloid cells show systemic and vascular inflammation as well as endothelial dysfunction. A decrease in circulating IL-6 levels by replacing IL-6-producing myeloid cells in the BM improved vascular dysfunction in this model, underpinning the relevant role of IL-6 in vascular disease.
RESUMO
Interleukin-17A- (IL-17A) and IL-17F-producing CD4+ T helper cells (TH17 cells) are implicated in the development of chronic inflammatory diseases, such as multiple sclerosis and its animal model, experimental autoimmune encephalomyelitis (EAE). TH17 cells also orchestrate leukocyte invasion of the central nervous system (CNS) and subsequent tissue damage. However, the role of IL-17A and IL-17F as effector cytokines is still confused with the encephalitogenic function of the cells that produce these cytokines, namely, TH17 cells, fueling a long-standing debate in the neuroimmunology field. Here, we demonstrated that mice deficient for IL-17A/F lose their susceptibility to EAE, which correlated with an altered composition of their gut microbiota. However, loss of IL-17A/F in TH cells did not diminish their encephalitogenic capacity. Reconstitution of a wild-type-like intestinal microbiota or reintroduction of IL-17A specifically into the gut epithelium of IL-17A/F-deficient mice reestablished their susceptibility to EAE. Thus, our data demonstrated that IL-17A and IL-17F are not encephalitogenic mediators but rather modulators of intestinal homeostasis that indirectly alter CNS-directed autoimmunity.
Assuntos
Encefalomielite Autoimune Experimental/imunologia , Microbioma Gastrointestinal/imunologia , Interleucina-17/metabolismo , Esclerose Múltipla/imunologia , Transferência Adotiva , Animais , Sistema Nervoso Central/imunologia , Sistema Nervoso Central/patologia , Encefalomielite Autoimune Experimental/microbiologia , Encefalomielite Autoimune Experimental/patologia , Transplante de Microbiota Fecal , Feminino , Humanos , Interleucina-17/genética , Masculino , Camundongos , Camundongos Knockout , Esclerose Múltipla/patologia , Células Th17/imunologia , Células Th17/transplanteRESUMO
The vast majority of Foxp3+ regulatory T cells (Tregs) are generated in the thymus, and several factors, such as cytokines and unique thymic antigen-presenting cells, are known to contribute to the development of these thymus-derived Tregs (tTregs). Here, we report the existence of a specific subset of Foxp3+ Tregs within the thymus that is characterized by the expression of IL-1R2, which is a decoy receptor for the inflammatory cytokine IL-1. Detailed flow cytometric analysis of the thymocytes from Foxp3hCD2xRAG1GFP reporter mice revealed that the IL-1R2+ Tregs are mainly RAG1GFP- and CCR6+CCR7-, demonstrating that these Tregs are recirculating cells entering the thymus from the periphery and that they have an activated phenotype. In the spleen, the majority of IL-1R2+ Tregs express neuropilin-1 (Nrp-1) and Helios, suggesting a thymic origin for these Tregs. Interestingly, among all tissues studied, the highest frequency of IL-1R2+ Tregs was observed in the thymus, indicating preferential recruitment of this Treg subset by the thymus. Using fetal thymic organ cultures (FTOCs), we demonstrated that increased concentrations of exogenous IL-1ß blocked intrathymic Treg development, resulting in a decreased frequency of CD25+Foxp3+ tTregs and an accumulation of CD25+Foxp3- Treg precursors. Interestingly, the addition of IL-1R2+ Tregs, but not IL-1R2- Tregs, to reaggregated thymic organ cultures (RTOCs) abrogated the IL-1ß-mediated blockade, demonstrating that these recirculating IL-1R2+ Tregs can quench IL-1 signaling in the thymus and thereby maintain thymic Treg development even under inflammatory conditions.
Assuntos
Diferenciação Celular , Fatores de Transcrição Forkhead/fisiologia , Inflamação/imunologia , Receptores Tipo II de Interleucina-1/metabolismo , Linfócitos T Reguladores/citologia , Timócitos/citologia , Animais , Citocinas/metabolismo , Proteínas de Homeodomínio/fisiologia , Inflamação/metabolismo , Inflamação/patologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Baço/citologia , Baço/imunologia , Baço/metabolismo , Linfócitos T Reguladores/imunologia , Linfócitos T Reguladores/metabolismo , Timócitos/imunologia , Timócitos/metabolismoRESUMO
Patients with cancer with liver metastasis demonstrate significantly worse outcomes than those without liver metastasis when treated with anti-PD-1 immunotherapy. The mechanism of liver metastases-induced reduction in systemic antitumor immunity is unclear. Using a dual-tumor immunocompetent mouse model, we found that the immune response to tumor antigen presence within the liver led to the systemic suppression of antitumor immunity. The immune suppression was antigen specific and associated with the coordinated activation of regulatory T cells (Tregs) and modulation of intratumoral CD11b+ monocytes. The dysfunctional immune state could not be reversed by anti-PD-1 monotherapy unless Treg cells were depleted (anti-CTLA-4) or destabilized (EZH2 inhibitor). Thus, this study provides a mechanistic understanding and rationale for adding Treg and CD11b+ monocyte targeting agents in combination with anti-PD-1 to treat patients with cancer with liver metastasis.
Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Inibidores de Checkpoint Imunológico/farmacologia , Neoplasias Hepáticas/tratamento farmacológico , Linfócitos T Reguladores/imunologia , Evasão Tumoral/efeitos dos fármacos , Animais , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Antígeno CD11b/metabolismo , Linfócitos T CD8-Positivos/efeitos dos fármacos , Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/metabolismo , Antígeno CTLA-4/antagonistas & inibidores , Antígeno CTLA-4/metabolismo , Linhagem Celular Tumoral/transplante , Modelos Animais de Doenças , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Resistencia a Medicamentos Antineoplásicos/imunologia , Proteína Potenciadora do Homólogo 2 de Zeste/antagonistas & inibidores , Proteína Potenciadora do Homólogo 2 de Zeste/metabolismo , Feminino , Humanos , Inibidores de Checkpoint Imunológico/uso terapêutico , Neoplasias Hepáticas/imunologia , Neoplasias Hepáticas/secundário , Depleção Linfocítica/métodos , Linfócitos do Interstício Tumoral/efeitos dos fármacos , Linfócitos do Interstício Tumoral/imunologia , Linfócitos do Interstício Tumoral/metabolismo , Masculino , Camundongos , Camundongos Transgênicos , Linfócitos T Reguladores/efeitos dos fármacos , Linfócitos T Reguladores/metabolismo , Microambiente Tumoral/efeitos dos fármacos , Microambiente Tumoral/imunologiaRESUMO
The proinflammatory cytokine interleukin 1 (IL-1) is crucially involved in the pathogenesis of multiple sclerosis (MS) and its animal model experimental autoimmune encephalomyelitis (EAE). Herein, we studied the role of IL-1 signaling in blood-brain barrier (BBB) endothelial cells (ECs), astrocytes and microglia for EAE development, using mice with the conditional deletion of its signaling receptor IL-1R1. We found that IL-1 signaling in microglia and astrocytes is redundant for the development of EAE, whereas the IL-1R1 deletion in BBB-ECs markedly ameliorated disease severity. IL-1 signaling in BBB-ECs upregulated the expression of the adhesion molecules Vcam-1, Icam-1 and the chemokine receptor Darc, all of which have been previously shown to promote CNS-specific inflammation. In contrast, IL-1R1 signaling suppressed the expression of the stress-responsive heme catabolizing enzyme heme oxygenase-1 (HO-1) in BBB-ECs, promoting disease progression via a mechanism associated with deregulated expression of the IL-1-responsive genes Vcam1, Icam1 and Ackr1 (Darc). Mechanistically, our data emphasize a functional crosstalk of BBB-EC IL-1 signaling and HO-1, controlling the transcription of downstream proinflammatory genes promoting the pathogenesis of autoimmune neuroinflammation.
Assuntos
Barreira Hematoencefálica/enzimologia , Encefalomielite Autoimune Experimental/imunologia , Células Endoteliais/enzimologia , Heme Oxigenase-1/metabolismo , Inflamação/imunologia , Interleucina-1/imunologia , Animais , Barreira Hematoencefálica/imunologia , Encefalomielite Autoimune Experimental/enzimologia , Regulação da Expressão Gênica/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Transdução de Sinais/imunologiaRESUMO
The pro-inflammatory cytokine interleukin-1 (IL-1) plays a key role in many physiological processes and during the inflammatory and immune response to most common diseases. IL-1 exists as two agonists, IL-1α and IL-1ß that bind to the only signaling IL-1 type 1 receptor (IL-1R1), while a second decoy IL-1 type 2 receptor (IL-1R2) binds both forms of IL-1 without inducing cell signaling. The field of immunology and inflammation research has, over the past 35 years, unraveled many mechanisms of IL-1 actions, through in vitro manipulation of the IL-1 system or by using genetically engineered mouse models that lack either member of the IL-1 family in ubiquitous constitutive manner. However, the limitation of global mouse knockout technology has significantly hampered our understanding of the precise mechanisms of IL-1 actions in animal models of disease. Here we report and review the recent generation of new conditional mouse mutants in which exons of Il1a, Il1b, Il1r1, and Il1r2 genes flanked by loxP sites (fl/fl) can be deleted in cell-/tissue-specific constitutive or inducible manner by Cre recombinase expression. Hence, IL-1αfl/fl, IL-1ßfl/fl, IL-1R1fl/fl, and IL-1R2fl/fl mice constitute a new toolbox that will provide a step change in our understanding of the cell-specific role of IL-1 and its receptor in health and disease and the potential development of targeted IL-1 therapies.
Assuntos
Interleucina-1/metabolismo , Animais , Humanos , Inflamação/metabolismo , Ligantes , Receptores de Interleucina-1/metabolismo , Transdução de Sinais/fisiologiaRESUMO
IL-6 binds to the IL-6R α-chain (IL-6Rα) and signals via the signal transducer gp130. Recently, IL-6 was found to also bind to the cell surface glycoprotein CD5, which would then engage gp130 in the absence of IL-6Rα. However, the biological relevance of this alternative pathway is under debate. In this study, we developed a mouse model, in which murine IL-6 is overexpressed in a CD11c-Cre-dependent manner. Transgenic mice developed a lethal immune dysregulation syndrome with increased numbers of Ly-6G+ neutrophils and Ly-6Chi monocytes/macrophages. IL-6 overexpression promoted activation of CD4+ T cells while suppressing CD5+ B-1a cell development. However, additional ablation of IL-6Rα protected IL-6-overexpressing mice from IL-6-triggered inflammation and fully phenocopied IL-6Rα-deficient mice without IL-6 overexpression. Mechanistically, IL-6Rα deficiency completely prevented downstream activation of STAT3 in response to IL-6. Altogether, our data clarify that IL-6Rα is the only biologically relevant receptor for IL-6 in mice.
Assuntos
Interleucina-6/imunologia , Receptores de Interleucina-6/imunologia , Transdução de Sinais/imunologia , Animais , Camundongos , Camundongos TransgênicosRESUMO
Chronic inflammation drives the progression of colorectal cancer (CRC). Increased expression of interleukin (IL)-17A is associated with poor prognosis, and IL-17A blockade curbs tumor progression in preclinical models of CRC. Here we examined the impact of IL-1 signaling, a key regulator of the IL-17 pathway, in different cell types within the CRC microenvironment. Genetic deletion of the IL-1 receptor (IL-1R1) in epithelial cells alleviated tumorigenesis in the APC model of CRC, demonstrating a cell-autonomous role for IL-1 signaling in early tumor seed outgrowth. T cell specific ablation of IL-1R1 decreased tumor-elicited inflammation dependent on IL-17 and IL-22, thereby reducing CRC progression. The pro-tumorigenic roles of IL-1 were counteracted by its effects on myeloid cells, particularly neutrophils, where IL-1R1 ablation resulted in bacterial invasion into tumors, heightened inflammation and aggressive CRC progression. Thus, IL-1 signaling elicits cell-type-specific responses, which, in aggregate, set the inflammatory tone of the tumor microenvironment and determine the propensity for disease progression.
Assuntos
Neoplasias Colorretais/imunologia , Inflamação/metabolismo , Interleucina-17/metabolismo , Interleucina-1/metabolismo , Neutrófilos/imunologia , Salmonelose Animal/imunologia , Salmonella/imunologia , Animais , Carcinogênese , Células Cultivadas , Humanos , Interleucina-1/genética , Interleucina-1/imunologia , Interleucinas/metabolismo , Camundongos , Camundongos Knockout , Neutrófilos/ultraestrutura , Especificidade de Órgãos , Receptores de Interleucina-1/genética , Transdução de Sinais , Microambiente Tumoral , Interleucina 22RESUMO
TNF is a multifunctional cytokine involved in autoimmune disease pathogenesis that exerts its effects through two distinct TNF receptors, TNFR1 and TNFR2. While TNF- and TNFR1-deficient (but not TNFR2-deficient) mice show very similar phenotypes, the significance of TNFR2 signaling in health and disease remains incompletely understood. Recent studies implicated the importance of the TNF/TNFR2 axis in T regulatory (Treg) cell functions. To definitively ascertain the significance of TNFR2 signaling, we generated and validated doubly humanized TNF/TNFR2 mice, with the option of conditional inactivation of TNFR2. These mice carry a functional human TNF-TNFR2 (hTNF-hTNFR2) signaling module and provide a useful tool for comparative evaluation of TNF-directed biologics. Conditional inactivation of TNFR2 in FoxP3+ cells in doubly humanized TNF/TNFR2 mice down-regulated the expression of Treg signature molecules (such as FoxP3, CD25, CTLA-4, and GITR) and diminished Treg suppressive function in vitro. Consequently, Treg-restricted TNFR2 deficiency led to significant exacerbation of experimental autoimmune encephalomyelitis (EAE), accompanied by reduced capacity to control Th17-mediated immune responses. Our findings expose the intrinsic and beneficial effects of TNFR2 signaling in Treg cells that could translate into protective functions in vivo, including treatment of autoimmunity.
Assuntos
Autoimunidade/imunologia , Sistema Nervoso Central/imunologia , Modelos Animais de Doenças , Encefalomielite Autoimune Experimental/prevenção & controle , Receptores Tipo II do Fator de Necrose Tumoral/fisiologia , Linfócitos T Reguladores/imunologia , Fator de Necrose Tumoral alfa/fisiologia , Animais , Células Cultivadas , Sistema Nervoso Central/metabolismo , Sistema Nervoso Central/patologia , Encefalomielite Autoimune Experimental/imunologia , Encefalomielite Autoimune Experimental/metabolismo , Regulação da Expressão Gênica , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Camundongos KnockoutRESUMO
The pleiotropic cytokine IL-1 mediates its biological functions via association with the signaling receptor IL-1R1. Despite an apparent simplicity in IL-1 signaling activation, multiple negative regulators have been identified. The decoy receptor IL-1R2 (also known as CD121b) can suppress IL-1 maturation, sequester its active forms or hinder the signaling complex assembly. IL-1R2 is differentially expressed among numerous cell types and displays cis- and trans- modes of action. In this review, we link different forms of IL-1R2 (membrane-bound (mIL-1R2), secreted (sIL-1R2), shedded (shIL-1R2), cytoplasmic, and intracellular domain (IL-1R2ICD) restricted) with their ability to interfere with IL-1, thereby regulating immune responses. We also discuss the intriguing possible function of IL-1R2 as a transcriptional regulator. Finally, we summarize the known impact of IL-1R2 in disease pathogenesis and discuss its potential role in treatment of inflammatory conditions.
Assuntos
Interleucina-1/metabolismo , Receptores Tipo II de Interleucina-1/metabolismo , Animais , Humanos , Transdução de SinaisRESUMO
IL-17A and IL-17F share the highest sequence homology of the IL-17 family and signal via the same IL-17RA/RC receptor heterodimer. To better explore the expression of these two cytokines, we used a double reporter mouse strain (IL-17DR mice), where IL-17A expressing cells are marked by enhanced green fluorescent protein (eGFP) while red fluorescence protein (RFP) reports the expression of IL-17F. In steady state, we found that Th17 and γδ T cells only expressed IL-17A, while IL-17F expression was restricted to CD8 T cells (Tc17) and innate lymphoid cells (ILC type 3) of the gut. In experimental autoimmune encephalomyelitis, the vast majority of CNS-infiltrating Th17 cells expressed IL-17A but not IL-17F. In contrast, anti-CD3-induced, TGF-ß-driven Th17 cells in the gut expressed both of these IL-17 cytokines. In line with this, in vitro differentiation of Th17 cells in the presence of IL-1ß led primarily to IL-17A expressing T cells, while TGF-ß induced IL-17F co-expressing Th17 cells. Our results suggest that expression of IL-17F is associated with non-pathogenic T cells, pointing to a differential function of IL-17A versus IL-17F. KEY MESSAGES: Naïve mice: CD4+ T cells and γδ T cells express IL-17A, and Tc17 cells express IL-17F. Gut ILC3 show differential expression of IL17A and F. Th17 differentiation with TGF-ß1 induces IL-17A and F, whereas IL-1ß induced cells expressing IL-17A. Th17 cells in EAE in CNS express IL-17A only. Gut Th17 cells induced by anti-CD3 express IL-17A and F together as skin γδ T cells of IMQ-treated mice.
Assuntos
Expressão Gênica , Interleucina-17/genética , Células Th17/metabolismo , Animais , Biomarcadores , Diferenciação Celular/imunologia , Suscetibilidade a Doenças , Encefalomielite Autoimune Experimental , Imunofenotipagem , Interleucina-17/metabolismo , Mucosa Intestinal/imunologia , Mucosa Intestinal/metabolismo , Mucosa Intestinal/patologia , Camundongos , Camundongos Transgênicos , Subpopulações de Linfócitos T/imunologia , Subpopulações de Linfócitos T/metabolismo , Células Th17/citologia , Células Th17/imunologiaRESUMO
Multiple sclerosis (MS) is a human neurodegenerative disease characterized by the invasion of autoreactive T cells from the periphery into the CNS. Application of pan-histone deacetylase inhibitors (HDACi) ameliorates experimental autoimmune encephalomyelitis (EAE), an animal model for MS, suggesting that HDACi might be a potential therapeutic strategy for MS. However, the function of individual HDAC members in the pathogenesis of EAE is not known. In this study we report that mice with a T cell-specific deletion of HDAC1 (using the Cd4-Cre deleter strain; HDAC1-cKO) were completely resistant to EAE despite the ability of HDAC1cKO CD4+ T cells to differentiate into Th17 cells. RNA sequencing revealed STAT1 as a prominent upstream regulator of differentially expressed genes in activated HDAC1-cKO CD4+ T cells and this was accompanied by a strong increase in phosphorylated STAT1 (pSTAT1). This suggests that HDAC1 controls STAT1 activity in activated CD4+ T cells. Increased pSTAT1 levels correlated with a reduced expression of the chemokine receptors Ccr4 and Ccr6, which are important for the migration of T cells into the CNS. Finally, EAE susceptibility was restored in WT:HDAC1-cKO mixed BM chimeric mice, indicating a cell-autonomous defect. Our data demonstrate a novel pathophysiological role for HDAC1 in EAE and provide evidence that selective inhibition of HDAC1 might be a promising strategy for the treatment of MS.
Assuntos
Encefalomielite Autoimune Experimental/metabolismo , Histona Desacetilase 1/metabolismo , Esclerose Múltipla/metabolismo , Fator de Transcrição STAT1/metabolismo , Células Th17/fisiologia , Animais , Movimento Celular , Células Cultivadas , Quimera , Modelos Animais de Doenças , Encefalomielite Autoimune Experimental/imunologia , Histona Desacetilase 1/genética , Humanos , Camundongos , Camundongos Knockout , Esclerose Múltipla/imunologia , Receptores CCR4/metabolismo , Receptores CCR6/metabolismo , Fator de Transcrição STAT1/genéticaRESUMO
Candida albicans is a dimorphic commensal fungus that causes severe oral infections in immunodeficient patients. Invasion of C. albicans hyphae into oral epithelium is an essential virulence trait. Interleukin-17 (IL-17) signaling is required for both innate and adaptive immunity to C. albicans During the innate response, IL-17 is produced by γδ T cells and a poorly understood population of innate-acting CD4+ αß T cell receptor (TCRαß)+ cells, but only the TCRαß+ cells expand during acute infection. Confirming the innate nature of these cells, the TCR was not detectably activated during the primary response, as evidenced by Nur77eGFP mice that report antigen-specific signaling through the TCR. Rather, the expansion of innate TCRαß+ cells was driven by both intrinsic and extrinsic IL-1R signaling. Unexpectedly, there was no requirement for CCR6/CCL20-dependent recruitment or prototypical fungal pattern recognition receptors. However, C. albicans mutants that cannot switch from yeast to hyphae showed impaired TCRαß+ cell proliferation and Il17a expression. This prompted us to assess the role of candidalysin, a hyphal-associated peptide that damages oral epithelial cells and triggers production of inflammatory cytokines including IL-1. Candidalysin-deficient strains failed to up-regulate Il17a or drive the proliferation of innate TCRαß+ cells. Moreover, candidalysin signaled synergistically with IL-17, which further augmented the expression of IL-1α/ß and other cytokines. Thus, IL-17 and C. albicans, via secreted candidalysin, amplify inflammation in a self-reinforcing feed-forward loop. These findings challenge the paradigm that hyphal formation per se is required for the oral innate response and demonstrate that establishment of IL-1- and IL-17-dependent innate immunity is induced by tissue-damaging hyphae.
Assuntos
Candida albicans/imunologia , Candidíase/imunologia , Células Epiteliais/imunologia , Proteínas Fúngicas/imunologia , Interleucina-17/imunologia , Imunidade Adaptativa/imunologia , Animais , Candida albicans/metabolismo , Candida albicans/fisiologia , Candidíase/microbiologia , Citocinas/imunologia , Citocinas/metabolismo , Células Epiteliais/microbiologia , Feminino , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Humanos , Hifas/imunologia , Hifas/metabolismo , Hifas/fisiologia , Imunidade Inata/imunologia , Interleucina-17/genética , Interleucina-17/metabolismo , Masculino , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Transgênicos , Mucosa Bucal/imunologia , Mucosa Bucal/microbiologia , Fatores de Virulência/genética , Fatores de Virulência/imunologia , Fatores de Virulência/metabolismoRESUMO
The function of NF-κB family members is controlled by multiple mechanisms including the transcriptional regulator Bcl-3, an atypical member of the IκB family. By using a murine model of conditional Bcl-3 overexpression specifically in T cells, we observed impairment in the development of Th2, Th1, and Th17 cells. High expression of Bcl-3 promoted CD4+ T-cell survival, but at the same time suppressed proliferation in response to TCR stimulation, resulting in reduced CD4+ T-cell expansion. As a consequence, T-cell-specific overexpression of Bcl-3 led to reduced inflammation in the small intestine of mice applied with anti-CD3 in a model of gut inflammation. Moreover, impaired Th17-cell development resulted in the resistance of Bcl-3 overexpressing mice to EAE, a mouse model of multiple sclerosis. Thus, we concluded that fine-tuning expression of Bcl-3 is needed for proper CD4+ T-cell development and is required to sustain Th17-cell mediated pathology.
Assuntos
Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD4-Positivos/metabolismo , Encefalomielite Autoimune Experimental/imunologia , Proteínas Proto-Oncogênicas/genética , Células Th17/imunologia , Fatores de Transcrição/genética , Animais , Proteína 3 do Linfoma de Células B , Complexo CD3/imunologia , Diferenciação Celular , Modelos Animais de Doenças , Encefalomielite Autoimune Experimental/induzido quimicamente , Encefalomielite Autoimune Experimental/fisiopatologia , Inflamação , Intestino Delgado/imunologia , Ativação Linfocitária , Camundongos , Camundongos Endogâmicos C57BL , Proteínas Proto-Oncogênicas/metabolismo , Células Th1/imunologia , Células Th2/imunologia , Fatores de Transcrição/metabolismoRESUMO
Bcl-3 is an atypical NF-κB family member that regulates NF-κB-dependent gene expression in effector T cells, but a cell-intrinsic function in regulatory T (Treg) cells and colitis is not clear. Here we show that Bcl-3 expression levels in colonic T cells correlate with disease manifestation in patients with inflammatory bowel disease. Mice with T-cell-specific overexpression of Bcl-3 develop severe colitis that can be attributed to defective Treg cell development and function, leading to the infiltration of immune cells such as pro-inflammatory γδT cells, but not αß T cells. In Treg cells, Bcl-3 associates directly with NF-κB p50 to inhibit DNA binding of p50/p50 and p50/p65 NF-κB dimers, thereby regulating NF-κB-mediated gene expression. This study thus reveals intrinsic functions of Bcl-3 in Treg cells, identifies Bcl-3 as a potential prognostic marker for colitis and illustrates the mechanism by which Bcl-3 regulates NF-κB activity in Tregs to prevent colitis.
Assuntos
Colite/metabolismo , Proteínas Proto-Oncogênicas/metabolismo , Linfócitos T Reguladores/metabolismo , Fatores de Transcrição/metabolismo , Adulto , Animais , Proteína 3 do Linfoma de Células B , Colite/genética , Feminino , Regulação da Expressão Gênica , Células HEK293 , Humanos , Masculino , Camundongos Endogâmicos C57BL , Camundongos Knockout , Pessoa de Meia-Idade , NF-kappa B/metabolismo , Subunidade p50 de NF-kappa B/metabolismo , Ligação Proteica , Proteínas Proto-Oncogênicas/genética , Fator de Transcrição RelA/metabolismo , Fatores de Transcrição/genética , Adulto JovemRESUMO
TGF-ß is an anti-inflammatory cytokine whose signaling is negatively controlled by Smad7. Previously, we established a role for Smad7 in the generation of autoreactive T cells; however, the function of Smad7 in dendritic cells (DCs) remains elusive. Here, we demonstrate that DC-specific Smad7 deficiency resulted in elevated expression of the transcription factors Batf3 and IRF8, leading to increased frequencies of CD8+CD103+ DCs in the spleen. Furthermore, Smad7-deficient DCs expressed higher levels of indoleamine 2,3-dioxygenase (IDO), an enzyme associated with tolerance induction. Mice devoid of Smad7 specifically in DCs are resistant to the development of experimental autoimmune encephalomyelitis (EAE) as a result of an increase of protective regulatory T cells (Tregs) and reduction of encephalitogenic effector T cells in the central nervous system. In agreement, inhibition of IDO activity or depletion of Tregs restored disease susceptibility. Intriguingly, when Smad7-deficient DCs also lacked the IFN-γ receptor, the mice regained susceptibility to EAE, demonstrating that IFN-γ signaling in DCs mediates their tolerogenic function. Our data indicate that Smad7 expression governs splenic DC subset differentiation and is critical for the promotion of their efficient function in immunity.
Assuntos
Autoimunidade/fisiologia , Células Dendríticas/metabolismo , Proteína Smad7/metabolismo , Fator de Crescimento Transformador beta/metabolismo , Animais , Fatores de Transcrição de Zíper de Leucina Básica/metabolismo , Linfócitos T CD8-Positivos/metabolismo , Diferenciação Celular/fisiologia , Citocinas/metabolismo , Encefalomielite Autoimune Experimental/metabolismo , Tolerância Imunológica , Indolamina-Pirrol 2,3,-Dioxigenase/metabolismo , Fatores Reguladores de Interferon/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Transdução de Sinais/fisiologia , Baço/metabolismo , Linfócitos T Reguladores/metabolismoRESUMO
Arrival of encephalitogenic T cells at inflammatory foci represents a critical step in development of experimental autoimmune encephalomyelitis (EAE), the animal model for multiple sclerosis. EBI2 and its ligand, 7α,25-OHC, direct immune cell localization in secondary lymphoid organs. CH25H and CYP7B1 hydroxylate cholesterol to 7α,25-OHC. During EAE, we found increased expression of CH25H by microglia and CYP7B1 by CNS-infiltrating immune cells elevating the ligand concentration in the CNS. Two critical pro-inflammatory cytokines, interleukin-23 (IL-23) and interleukin-1 beta (IL-1ß), maintained expression of EBI2 in differentiating Th17 cells. In line with this, EBI2 enhanced early migration of encephalitogenic T cells into the CNS in a transfer EAE model. Nonetheless, EBI2 was dispensable in active EAE. Human Th17 cells do also express EBI2, and EBI2 expressing cells are abundant within multiple sclerosis (MS) white matter lesions. These findings implicate EBI2 as a mediator of CNS autoimmunity and describe mechanistically its contribution to the migration of autoreactive T cells into inflamed organs.
Assuntos
Linfócitos T CD4-Positivos/metabolismo , Linfócitos T CD4-Positivos/fisiologia , Movimento Celular/fisiologia , Sistema Nervoso Central/metabolismo , Encefalomielite Autoimune Experimental/metabolismo , Esclerose Múltipla/metabolismo , Receptores Acoplados a Proteínas G/metabolismo , Animais , Autoimunidade/fisiologia , Sistema Nervoso Central/fisiologia , Família 7 do Citocromo P450/metabolismo , Modelos Animais de Doenças , Encefalomielite Autoimune Experimental/patologia , Feminino , Interleucina-1beta/metabolismo , Interleucina-23/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Esteroide Hidroxilases/metabolismo , Células Th17/metabolismo , Células Th17/fisiologiaRESUMO
Interleukin-1 (IL-1) is implicated in numerous pathologies, including multiple sclerosis and its animal model experimental autoimmune encephalomyelitis (EAE). However, the exact mechanism by which IL-1 is involved in the generation of pathogenic T cells and in disease development remains largely unknown. We found that following EAE induction, pertussis toxin administration leads to IL-1 receptor type 1 (IL-1R1)-dependent IL-1ß expression by myeloid cells in the draining lymph nodes. This myeloid-derived IL-1ß did not vitally contribute to the generation and plasticity of Th17 cells, but rather promoted the expansion of a GM-CSF+ Th17 cell subset, thereby enhancing its encephalitogenic potential. Lack of expansion of GM-CSF-producing Th17 cells led to ameliorated disease in mice deficient for IL-1R1 specifically in T cells. Importantly, pathogenicity of IL-1R1-deficient T cells was fully restored by IL-23 polarization and expansion in vitro Therefore, our data demonstrate that IL-1 functions as a mitogenic mediator of encephalitogenic Th17 cells rather than qualitative inducer of their generation.
Assuntos
Proliferação de Células , Encefalomielite Autoimune Experimental/patologia , Fator Estimulador de Colônias de Granulócitos e Macrófagos/análise , Interleucina-1/metabolismo , Células Th17/química , Células Th17/fisiologia , Animais , Camundongos , Toxina Pertussis/administração & dosagem , Toxina Pertussis/toxicidadeRESUMO
Interleukin-1 (IL-1) plays a crucial role in numerous inflammatory diseases via action on its only known signaling IL-1 receptor type 1 (IL-1R1). To investigate the role of IL-1 signaling in selected cell types, we generated a new mouse strain in which exon 5 of the Il1r1 gene is flanked by loxP sites. Crossing of these mice with CD4-Cre transgenic mice resulted in IL-1R1 loss of function specifically in T cells. These mice, termed IL-1R1ΔT, displayed normal development under steady state conditions. Importantly, isolated CD4 positive T cells retained their capacity to differentiate toward Th1 or Th17 cell lineages in vitro, and strongly proliferated in cultures supplemented with either anti-CD3/CD28 or Concanavalin A, but, as predicted, were completely unresponsive to IL-1ß administration. Furthermore, IL-1R1ΔT mice were protected from gut inflammation in the anti-CD3 treatment model, due to dramatically reduced frequencies and absolute numbers of IL-17A and interferon (IFN)-γ producing cells. Taken together, our data shows the necessity of intact IL-1 signaling for survival and expansion of CD4 T cells that were developed in an otherwise IL-1 sufficient environment.
Assuntos
Linfócitos T CD4-Positivos/metabolismo , Sobrevivência Celular/genética , Citocinas/biossíntese , Receptores Tipo I de Interleucina-1/deficiência , Subpopulações de Linfócitos T/metabolismo , Animais , Anticorpos Monoclonais/farmacologia , Linfócitos B/metabolismo , Biomarcadores , Complexo CD3/imunologia , Complexo CD3/metabolismo , Linfócitos T CD4-Positivos/efeitos dos fármacos , Linfócitos T CD4-Positivos/imunologia , Proliferação de Células , Marcação de Genes , Imunofenotipagem , Interleucina-1/metabolismo , Interleucina-1beta/metabolismo , Interleucina-1beta/farmacologia , Ativação Linfocitária , Camundongos , Camundongos Knockout , Camundongos Transgênicos , Fenótipo , Receptores Tipo I de Interleucina-1/genética , Transdução de Sinais , Subpopulações de Linfócitos T/efeitos dos fármacos , Subpopulações de Linfócitos T/imunologiaRESUMO
Leukocyte infiltration of the central nervous system (CNS) occurs under certain pathogenic conditions and most often results in severe disorders. Therefore, the isolation and analysis of such infiltrating cell populations is necessary for elucidating the underlying pathogenic mechanisms. Here we describe a simple and straightforward protocol for cell isolation from the inflamed CNS, which combines mechanical dissociation and enzymatic degradation of the tissue. Additionally, purification by Percoll gradient centrifugation provides a great yield of the infiltrating material. The isolated cells can be further used for downstream applications such as cell sorting, cellular or molecular analysis.