RESUMO
The contribution of CD4+ T cells to protective or pathogenic immune responses to SARS-CoV-2 infection remains unknown. Here, we present single-cell transcriptomic analysis of >100,000 viral antigen-reactive CD4+ T cells from 40 COVID-19 patients. In hospitalized patients compared to non-hospitalized patients, we found increased proportions of cytotoxic follicular helper cells and cytotoxic T helper (TH) cells (CD4-CTLs) responding to SARS-CoV-2 and reduced proportion of SARS-CoV-2-reactive regulatory T cells (TREG). Importantly, in hospitalized COVID-19 patients, a strong cytotoxic TFH response was observed early in the illness, which correlated negatively with antibody levels to SARS-CoV-2 spike protein. Polyfunctional TH1 and TH17 cell subsets were underrepresented in the repertoire of SARS-CoV-2-reactive CD4+ T cells compared to influenza-reactive CD4+ T cells. Together, our analyses provide insights into the gene expression patterns of SARS-CoV-2-reactive CD4+ T cells in distinct disease severities.
Assuntos
COVID-19/imunologia , SARS-CoV-2/genética , Células T Auxiliares Foliculares/imunologia , Linfócitos T Citotóxicos/imunologia , Linfócitos T Reguladores/imunologia , Transcriptoma , Adulto , Idoso , Idoso de 80 Anos ou mais , Anticorpos Antivirais/sangue , Anticorpos Antivirais/imunologia , Contagem de Linfócito CD4 , COVID-19/epidemiologia , COVID-19/virologia , Estudos de Coortes , Inglaterra/epidemiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Índice de Gravidade de Doença , Análise de Célula Única/métodos , Glicoproteína da Espícula de Coronavírus/imunologiaRESUMO
The balance of myeloid populations and lymphoid populations must be well controlled. Here we found that osteopontin (OPN) skewed this balance during pathogenic conditions such as infection and autoimmunity. Notably, two isoforms of OPN exerted distinct effects in shifting this balance through cell-type-specific regulation of apoptosis. Intracellular OPN (iOPN) diminished the population size of myeloid progenitor cells and myeloid cells, and secreted OPN (sOPN) increase the population size of lymphoid cells. The total effect of OPN on skewing the leukocyte population balance was observed as host sensitivity to early systemic infection with Candida albicans and T cell-mediated colitis. Our study suggests previously unknown detrimental roles for two OPN isoforms in causing the imbalance of leukocyte populations.
Assuntos
Doenças Autoimunes/imunologia , Candidíase/imunologia , Colite/imunologia , Infecções/imunologia , Linfócitos/imunologia , Células Mieloides/imunologia , Osteopontina/imunologia , Animais , Apoptose , Candida albicans , Proliferação de Células , Ensaio de Imunoadsorção Enzimática , Citometria de Fluxo , Linfopoese/imunologia , Camundongos , Camundongos Knockout , Mielopoese/imunologia , Osteopontina/genética , Isoformas de Proteínas , Reação em Cadeia da Polimerase em Tempo Real , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Linfócitos TRESUMO
Activated CD8+ T cells differentiate into cytotoxic effector (TEFF) cells that eliminate target cells. How TEFF cell identity is established and maintained is not fully understood. We found that Runx3 deficiency limited clonal expansion and impaired upregulation of cytotoxic molecules in TEFF cells. Runx3-deficient CD8+ TEFF cells aberrantly upregulated genes characteristic of follicular helper T (TFH) cell lineage, including Bcl6, Tcf7 and Cxcr5. Mechanistically, the Runx3-CBFß transcription factor complex deployed H3K27me3 to Bcl6 and Tcf7 genes to suppress the TFH program. Ablating Tcf7 in Runx3-deficient CD8+ TEFF cells prevented the upregulation of TFH genes and ameliorated their defective induction of cytotoxic genes. As such, Runx3-mediated Tcf7 repression coordinately enforced acquisition of cytotoxic functions and protected the cytotoxic lineage integrity by preventing TFH-lineage deviation.
Assuntos
Subunidade alfa 3 de Fator de Ligação ao Core/genética , Linfopoese/genética , Linfócitos T Citotóxicos/citologia , Linfócitos T Auxiliares-Indutores/citologia , Animais , Linhagem da Célula , Ensaio de Imunoadsorção Enzimática , Epigênese Genética , Regulação da Expressão Gênica , Fator 1-alfa Nuclear de Hepatócito/genética , Imuno-Histoquímica , Camundongos , Proteínas Proto-Oncogênicas c-bcl-6/genética , Receptores CXCR5/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Análise de Sequência de RNA , Regulação para CimaRESUMO
Glutamine metabolism provides synergistic support for macrophage activation and elicitation of desirable immune responses; however, the underlying mechanisms regulated by glutamine metabolism to orchestrate macrophage activation remain unclear. Here we show that the production of α-ketoglutarate (αKG) via glutaminolysis is important for alternative (M2) activation of macrophages, including engagement of fatty acid oxidation (FAO) and Jmjd3-dependent epigenetic reprogramming of M2 genes. This M2-promoting mechanism is further modulated by a high αKG/succinate ratio, whereas a low ratio strengthens the proinflammatory phenotype in classically activated (M1) macrophages. As such, αKG contributes to endotoxin tolerance after M1 activation. This study reveals new mechanistic regulations by which glutamine metabolism tailors the immune responses of macrophages through metabolic and epigenetic reprogramming.
Assuntos
Reprogramação Celular/imunologia , Epigênese Genética , Ácidos Cetoglutáricos/imunologia , Ativação de Macrófagos/imunologia , Macrófagos/imunologia , Animais , Imunoprecipitação da Cromatina , Ciclo do Ácido Cítrico/imunologia , Ácidos Graxos/metabolismo , Perfilação da Expressão Gênica , Glutamina/metabolismo , Glicólise/imunologia , Ácidos Cetoglutáricos/metabolismo , Lipopolissacarídeos , Macrófagos/metabolismo , Metabolômica , Camundongos , NF-kappa B/imunologia , Oxirredução , Fosforilação Oxidativa , Fenótipo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Análise de Sequência de RNA , Ácido Succínico/metabolismoRESUMO
Among the features that distinguish type 1 innate lymphoid cells (ILC1s) from natural killer (NK) cells is a gene signature indicative of 'imprinting' by cytokines of the TGF-ß family. We studied mice in which ILC1s and NK cells lacked SMAD4, a signal transducer that facilitates the canonical signaling pathway common to all cytokines of the TGF-ß family. While SMAD4 deficiency did not affect ILC1 differentiation, NK cells unexpectedly acquired an ILC1-like gene signature and were unable to control tumor metastasis or viral infection. Mechanistically, SMAD4 restrained non-canonical TGF-ß signaling mediated by the cytokine receptor TGFßR1 in NK cells. NK cells from a SMAD4-deficient person affected by polyposis were also hyper-responsive to TGF-ß. These results identify SMAD4 as a previously unknown regulator that restricts non-canonical TGF-ß signaling in NK cells.
Assuntos
Células Matadoras Naturais/citologia , Linfopoese/genética , Proteína Smad4/genética , Fator de Crescimento Transformador beta/imunologia , Polipose Adenomatosa do Colo/genética , Polipose Adenomatosa do Colo/imunologia , Animais , Estudos de Casos e Controles , Diferenciação Celular , Perfilação da Expressão Gênica , Humanos , Imunidade Inata/imunologia , Immunoblotting , Síndromes de Imunodeficiência/genética , Síndromes de Imunodeficiência/imunologia , Linfócitos/citologia , Melanoma Experimental/imunologia , Camundongos , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transdução de Sinais/imunologia , Proteína Smad4/imunologiaRESUMO
Translation is a critical process in protein synthesis, but translational regulation in antigen-specific T cells in vivo has not been well defined. Here we have characterized the translatome of virus-specific CD8+ effector T cells (Teff cells) during acute infection of mice with lymphocytic choriomeningitis virus (LCMV). Antigen-specific T cells exerted dynamic translational control of gene expression that correlated with cell proliferation and stimulation via the T cell antigen receptor (TCR). The translation of mRNAs that encode translation machinery, including ribosomal proteins, was upregulated during the T cell clonal-expansion phase, followed by inhibition of the translation of those transcripts when the CD8+ Teff cells stopped dividing just before the contraction phase. That translational suppression was more pronounced in terminal effector cells than in memory precursor cells and was regulated by antigenic stimulation and signals from the kinase mTOR. Our studies show that translation of transcripts encoding ribosomal proteins is regulated during the differentiation of CD8+ Teff cells and might have a role in fate 'decisions' involved in the formation of memory cells.
Assuntos
Infecções por Arenaviridae/imunologia , Linfócitos T CD8-Positivos/imunologia , Diferenciação Celular/imunologia , Biossíntese de Proteínas/imunologia , Animais , Infecções por Arenaviridae/genética , Infecções por Arenaviridae/metabolismo , Linfócitos T CD8-Positivos/metabolismo , Diferenciação Celular/genética , Citometria de Fluxo , Regulação da Expressão Gênica , Memória Imunológica/imunologia , Interferon gama/imunologia , Vírus da Coriomeningite Linfocítica , Camundongos , Biossíntese de Proteínas/genética , RNA Mensageiro/metabolismo , Receptores de Antígenos de Linfócitos T/imunologia , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Proteínas Ribossômicas/genética , Proteínas Ribossômicas/metabolismo , Serina-Treonina Quinases TOR/imunologiaRESUMO
The single-nucleotide polymorphism rs1990760 in the gene encoding the cytosolic viral sensor IFIH1 results in an amino-acid change (A946T; IFIH1T946) that is associated with multiple autoimmune diseases. The effect of this polymorphism on both viral sensing and autoimmune pathogenesis remains poorly understood. Here we found that human peripheral blood mononuclear cells (PBMCs) and cell lines expressing the risk variant IFIH1T946 exhibited heightened basal and ligand-triggered production of type I interferons. Consistent with those findings, mice with a knock-in mutation encoding IFIH1T946 displayed enhanced basal expression of type I interferons, survived a lethal viral challenge and exhibited increased penetrance in autoimmune models, including a combinatorial effect with other risk variants. Furthermore, IFIH1T946 mice manifested an embryonic survival defect consistent with enhanced responsiveness to RNA self ligands. Together our data support a model wherein the production of type I interferons driven by an autoimmune risk variant and triggered by ligand functions to protect against viral challenge, which probably accounts for its selection within human populations but provides this advantage at the cost of modestly promoting the risk of autoimmunity.
Assuntos
Autoimunidade/genética , Infecções por Cardiovirus/genética , Interferon Tipo I/imunologia , Helicase IFIH1 Induzida por Interferon/genética , Adolescente , Adulto , Animais , Doenças Autoimunes/genética , Doenças Autoimunes/imunologia , Autoimunidade/imunologia , Southern Blotting , Infecções por Cardiovirus/imunologia , Diabetes Mellitus Experimental/genética , Diabetes Mellitus Experimental/imunologia , Diabetes Mellitus Tipo 1/genética , Diabetes Mellitus Tipo 1/imunologia , Vírus da Encefalomiocardite/imunologia , Feminino , Predisposição Genética para Doença , Células HEK293 , Humanos , Immunoblotting , Helicase IFIH1 Induzida por Interferon/imunologia , Masculino , Camundongos , Pessoa de Meia-Idade , Polimorfismo de Nucleotídeo Único , Reação em Cadeia da Polimerase em Tempo Real , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Viroses/genética , Viroses/imunologia , Adulto JovemRESUMO
Immunoglobulin A (IgA) maintains a symbiotic equilibrium with intestinal microbes. IgA induction in the gut-associated lymphoid tissues (GALTs) is dependent on microbial sampling and cellular interaction in the subepithelial dome (SED). However it is unclear how IgA induction is predominantly initiated in the SED. Here we show that previously unrecognized mesenchymal cells in the SED of GALTs regulate bacteria-specific IgA production and diversify the gut microbiota. Mesenchymal cells expressing the cytokine RANKL directly interact with the gut epithelium to control CCL20 expression and microfold (M) cell differentiation. The deletion of mesenchymal RANKL impairs M cell-dependent antigen sampling and B cell-dendritic cell interaction in the SED, which results in a reduction in IgA production and a decrease in microbial diversity. Thus, the subepithelial mesenchymal cells that serve as M cell inducers have a fundamental role in the maintenance of intestinal immune homeostasis.
Assuntos
Microbioma Gastrointestinal/imunologia , Imunoglobulina A/imunologia , Tecido Linfoide/imunologia , Células-Tronco Mesenquimais/imunologia , Ligante RANK/imunologia , Animais , Linfócitos B/imunologia , Biodiversidade , Diferenciação Celular/imunologia , Quimiocina CCL20/imunologia , Células Dendríticas/imunologia , Citometria de Fluxo , Microbioma Gastrointestinal/genética , Centro Germinativo , Tecido Linfoide/citologia , Células-Tronco Mesenquimais/ultraestrutura , Camundongos , Microscopia Eletrônica , Ligante RANK/genética , RNA Ribossômico 16S/genética , Reação em Cadeia da Polimerase Via Transcriptase ReversaRESUMO
T cell antigen receptor (TCR) signaling in the thymus initiates positive selection, but the CD8+-lineage fate is thought to be induced by cytokines after TCR signaling has ceased, although this remains controversial and unproven. We have identified four cytokines (IL-6, IFN-γ, TSLP and TGF-ß) that did not signal via the common γ-chain (γc) receptor but that, like IL-7 and IL-15, induced expression of the lineage-specifying transcription factor Runx3d and signaled the generation of CD8+ T cells. Elimination of in vivo signaling by all six of these 'lineage-specifying cytokines' during positive selection eliminated Runx3d expression and completely abolished the generation of CD8+ single-positive thymocytes. Thus, this study proves that signaling during positive selection by lineage-specifying cytokines is responsible for all CD8+-lineage-fate 'decisions' in the thymus.
Assuntos
Linfócitos T CD8-Positivos/imunologia , Linhagem da Célula/imunologia , Citocinas/imunologia , Timo/imunologia , Animais , Linfócitos T CD8-Positivos/metabolismo , Subunidade alfa 3 de Fator de Ligação ao Core/genética , Subunidade alfa 3 de Fator de Ligação ao Core/imunologia , Subunidade alfa 3 de Fator de Ligação ao Core/metabolismo , Citocinas/metabolismo , Citometria de Fluxo , Expressão Gênica/imunologia , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Transgênicos , Receptores de Antígenos de Linfócitos T/imunologia , Receptores de Antígenos de Linfócitos T/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transdução de Sinais/imunologia , Timócitos/imunologia , Timócitos/metabolismo , Timo/citologia , Timo/metabolismoRESUMO
Trafficking of tissue dendritic cells (DCs) via lymph is critical for the generation of cellular immune responses in draining lymph nodes (LNs). In the current study we found that DCs docked to the basolateral surface of lymphatic vessels and transited to the lumen through hyaluronan-mediated interactions with the lymph-specific endothelial receptor LYVE-1, in dynamic transmigratory-cup-like structures. Furthermore, we show that targeted deletion of the gene Lyve1, antibody blockade or depletion of the DC hyaluronan coat not only delayed lymphatic trafficking of dermal DCs but also blunted their capacity to prime CD8+ T cell responses in skin-draining LNs. Our findings uncovered a previously unknown function for LYVE-1 and show that transit through the lymphatic network is initiated by the recognition of leukocyte-derived hyaluronan.
Assuntos
Células Dendríticas/imunologia , Células Endoteliais/metabolismo , Glicoproteínas/genética , Ácido Hialurônico/metabolismo , Vasos Linfáticos/metabolismo , Proteínas de Transporte Vesicular/metabolismo , Animais , Movimento Celular/imunologia , Células Dendríticas/metabolismo , Endotélio Linfático/citologia , Endotélio Linfático/metabolismo , Citometria de Fluxo , Glicoproteínas/metabolismo , Humanos , Imunidade Celular/imunologia , Linfonodos/imunologia , Proteínas de Membrana Transportadoras , Camundongos , Camundongos Knockout , Camundongos Transgênicos , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Linfócitos T/imunologiaRESUMO
The transcription regulator YAP controls organ size by regulating cell growth, proliferation and apoptosis. However, whether YAP has a role in innate antiviral immunity is largely unknown. Here we found that YAP negatively regulated an antiviral immune response. YAP deficiency resulted in enhanced innate immunity, a diminished viral load, and morbidity in vivo. YAP blocked dimerization of the transcription factor IRF3 and impeded translocation of IRF3 to the nucleus after viral infection. Notably, virus-activated kinase IKKÉ phosphorylated YAP at Ser403 and thereby triggered degradation of YAP in lysosomes and, consequently, relief of YAP-mediated inhibition of the cellular antiviral response. These findings not only establish YAP as a modulator of the activation of IRF3 but also identify a previously unknown regulatory mechanism independent of the kinases Hippo and LATS via which YAP is controlled by the innate immune pathway.
Assuntos
Proteínas Adaptadoras de Transdução de Sinal/imunologia , Fibroblastos/imunologia , Quinase I-kappa B/metabolismo , Imunidade Inata/imunologia , Lisossomos/metabolismo , Macrófagos/imunologia , Fosfoproteínas/imunologia , Infecções por Rhabdoviridae/imunologia , Proteínas Adaptadoras de Transdução de Sinal/genética , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Animais , Sistemas CRISPR-Cas , Proteínas de Ciclo Celular , Quimiocina CCL5/genética , Quimiocina CCL5/imunologia , Quimiocina CXCL10/genética , Quimiocina CXCL10/imunologia , Imunofluorescência , Edição de Genes , Células HEK293 , Células HeLa , Humanos , Immunoblotting , Imunoprecipitação , Fator Regulador 3 de Interferon/genética , Fator Regulador 3 de Interferon/imunologia , Fator Regulador 3 de Interferon/metabolismo , Interferon beta/genética , Interferon beta/imunologia , Pulmão/imunologia , Pulmão/patologia , Camundongos , Microscopia Confocal , Fosfoproteínas/genética , Fosfoproteínas/metabolismo , Fosforilação , Proteínas Serina-Treonina Quinases/genética , Proteínas Serina-Treonina Quinases/imunologia , Células RAW 264.7 , Reação em Cadeia da Polimerase em Tempo Real , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Infecções por Rhabdoviridae/patologia , Proteínas Supressoras de Tumor/genética , Proteínas Supressoras de Tumor/imunologia , Vesiculovirus , Carga Viral , Proteínas de Sinalização YAPRESUMO
The precise lineage relationship between innate lymphoid cells (ILCs) and lymphoid tissue-inducer (LTi) cells is poorly understood. Using single-cell multiplex transcriptional analysis of 100 lymphoid genes and single-cell cultures of fetal liver precursor cells, we identified the common proximal precursor to these lineages and found that its bifurcation was marked by differential induction of the transcription factors PLZF and TCF1. Acquisition of individual effector programs specific to the ILC subsets ILC1, ILC2 and ILC3 was initiated later, at the common ILC precursor stage, by transient expression of mixed ILC1, ILC2 and ILC3 transcriptional patterns, whereas, in contrast, the development of LTi cells did not go through multilineage priming. Our findings provide insight into the divergent mechanisms of the differentiation of the ILC lineage and LTi cell lineage and establish a high-resolution 'blueprint' of their development.
Assuntos
Linhagem da Célula/imunologia , Subpopulações de Linfócitos/imunologia , Linfócitos/imunologia , Linfócitos T Auxiliares-Indutores/imunologia , Animais , Diferenciação Celular/genética , Citometria de Fluxo , Perfilação da Expressão Gênica , Fator 1-alfa Nuclear de Hepatócito/imunologia , Fatores de Transcrição Kruppel-Like/genética , Fatores de Transcrição Kruppel-Like/imunologia , Tecido Linfoide/citologia , Camundongos , Reação em Cadeia da Polimerase Multiplex , Proteína com Dedos de Zinco da Leucemia Promielocítica , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Análise de Célula ÚnicaRESUMO
The role of anergy, an acquired state of T cell functional unresponsiveness, in natural peripheral tolerance remains unclear. In this study, we found that anergy was selectively induced in fetal antigen-specific maternal CD4(+) T cells during pregnancy. A naturally occurring subpopulation of anergic polyclonal CD4(+) T cells, enriched for self antigen-specific T cell antigen receptors, was also present in healthy hosts. Neuropilin-1 expression in anergic conventional CD4(+) T cells was associated with hypomethylation of genes related to thymic regulatory T cells (Treg cells), and this correlated with their ability to differentiate into Foxp3(+) Treg cells that suppressed immunopathology. Thus, our data suggest that not only is anergy induction important in preventing autoimmunity but also it generates the precursors for peripheral Treg cell differentiation.
Assuntos
Autoimunidade/imunologia , Diferenciação Celular/imunologia , Anergia Clonal/imunologia , Histocompatibilidade Materno-Fetal/imunologia , Tolerância Periférica/imunologia , Células Precursoras de Linfócitos T/imunologia , Linfócitos T Reguladores/imunologia , Transferência Adotiva , Animais , Artrite Experimental/imunologia , Linfócitos T CD4-Positivos/imunologia , Proliferação de Células , Citocinas/imunologia , Ensaio de Imunoadsorção Enzimática , Feminino , Citometria de Fluxo , Fatores de Transcrição Forkhead/imunologia , Genes Codificadores da Cadeia alfa de Receptores de Linfócitos T , Immunoblotting , Masculino , Camundongos , Camundongos Knockout , Neuropilina-1/metabolismo , Gravidez , Receptores de Antígenos de Linfócitos T/imunologia , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Tolerância a Antígenos Próprios , Timócitos/imunologiaRESUMO
Cyclic GMP-AMP synthase (cGAS) senses cytosolic DNA during viral infection and catalyzes synthesis of the dinucleotide cGAMP, which activates the adaptor STING to initiate antiviral responses. Here we found that deficiency in the carboxypeptidase CCP5 or CCP6 led to susceptibility to DNA viruses. CCP5 and CCP6 were required for activation of the transcription factor IRF3 and interferons. Polyglutamylation of cGAS by the enzyme TTLL6 impeded its DNA-binding ability, whereas TTLL4-mediated monoglutamylation of cGAS blocked its synthase activity. Conversely, CCP6 removed the polyglutamylation of cGAS, whereas CCP5 hydrolyzed the monoglutamylation of cGAS, which together led to the activation of cGAS. Therefore, glutamylation and deglutamylation of cGAS tightly modulate immune responses to infection with DNA viruses.
Assuntos
Carboxipeptidases/genética , Infecções por Vírus de DNA/metabolismo , DNA Viral/imunologia , Nucleotidiltransferases/metabolismo , Peptídeo Sintases/metabolismo , Animais , Citosol , Vírus de DNA/genética , Imunofluorescência , Herpes Simples/metabolismo , Imunoprecipitação , Fator Regulador 3 de Interferon/imunologia , Interferons/imunologia , Camundongos , Camundongos Knockout , Nucleotídeos Cíclicos/biossíntese , Nucleotidiltransferases/imunologia , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Simplexvirus/genética , Vacínia/metabolismo , Vaccinia virus/genéticaRESUMO
Aberrant nucleic acids generated during viral replication are the main trigger for antiviral immunity, and mutations that disrupt nucleic acid metabolism can lead to autoinflammatory disorders. Here we investigated the etiology of X-linked reticulate pigmentary disorder (XLPDR), a primary immunodeficiency with autoinflammatory features. We discovered that XLPDR is caused by an intronic mutation that disrupts the expression of POLA1, which encodes the catalytic subunit of DNA polymerase-α. Unexpectedly, POLA1 deficiency resulted in increased production of type I interferons. This enzyme is necessary for the synthesis of RNA:DNA primers during DNA replication and, strikingly, we found that POLA1 is also required for the synthesis of cytosolic RNA:DNA, which directly modulates interferon activation. Together this work identifies POLA1 as a critical regulator of the type I interferon response.
Assuntos
DNA Polimerase I/metabolismo , DNA/biossíntese , Interferon Tipo I/metabolismo , RNA/biossíntese , Sequência de Bases , Células Cultivadas , Citosol/metabolismo , DNA/genética , DNA Polimerase I/genética , Saúde da Família , Feminino , Fibroblastos/citologia , Fibroblastos/metabolismo , Perfilação da Expressão Gênica , Doenças Genéticas Ligadas ao Cromossomo X/genética , Doenças Genéticas Ligadas ao Cromossomo X/metabolismo , Células HEK293 , Células HeLa , Humanos , Immunoblotting , Masculino , Microscopia Confocal , Mutação , Análise de Sequência com Séries de Oligonucleotídeos , Linhagem , Transtornos da Pigmentação/genética , Transtornos da Pigmentação/metabolismo , RNA/genética , Reação em Cadeia da Polimerase Via Transcriptase ReversaRESUMO
Oral tolerance prevents pathological inflammatory responses to innocuous foreign antigens by peripheral regulatory T cells (pT(reg) cells). However, whether a particular subset of antigen-presenting cells (APCs) is required during dietary antigen exposure for the 'instruction' of naive CD4(+) T cells to differentiate into pT(reg) cells has not been defined. Using myeloid lineage-specific APC depletion in mice, we found that monocyte-derived APCs were dispensable, while classical dendritic cells (cDCs) were critical, for pT(reg) cell induction and oral tolerance. CD11b(-) cDCs from the gut-draining lymph nodes efficiently induced pT(reg) cells and, conversely, loss of transcription factor IRF8-dependent CD11b(-) cDCs impaired their polarization, although oral tolerance remained intact. These data reveal the hierarchy of cDC subsets in the induction of pT(reg) cells and their redundancy during the development of oral tolerance.
Assuntos
Antígenos/imunologia , Células Dendríticas/imunologia , Tolerância Imunológica/imunologia , Linfócitos T Reguladores/imunologia , Animais , Células Apresentadoras de Antígenos/imunologia , Células Apresentadoras de Antígenos/metabolismo , Antígeno CD11b/imunologia , Antígeno CD11b/metabolismo , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD4-Positivos/metabolismo , Diferenciação Celular/genética , Diferenciação Celular/imunologia , Células Cultivadas , Técnicas de Cocultura , Células Dendríticas/metabolismo , Dieta , Citometria de Fluxo , Tolerância Imunológica/genética , Imunização/métodos , Fatores Reguladores de Interferon/genética , Fatores Reguladores de Interferon/imunologia , Fatores Reguladores de Interferon/metabolismo , Linfonodos/imunologia , Linfonodos/metabolismo , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Transgênicos , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Linfócitos T Reguladores/metabolismo , Transcriptoma/genética , Transcriptoma/imunologiaRESUMO
The transcription factor Blimp-1 is necessary for the generation of plasma cells. Here we studied its functions in plasmablast differentiation by identifying regulated Blimp-1 target genes. Blimp-1 promoted the migration and adhesion of plasmablasts. It directly repressed genes encoding several transcription factors and Aicda (which encodes the cytidine deaminase AID) and thus silenced B cell-specific gene expression, antigen presentation and class-switch recombination in plasmablasts. It directly activated genes, which led to increased expression of the plasma cell regulator IRF4 and proteins involved in immunoglobulin secretion. Blimp-1 induced the transcription of immunoglobulin genes by controlling the 3' enhancers of the loci encoding the immunoglobulin heavy chain (Igh) and κ-light chain (Igk) and, furthermore, regulated the post-transcriptional expression switch from the membrane-bound form of the immunoglobulin heavy chain to its secreted form by activating Ell2 (which encodes the transcription-elongation factor ELL2). Notably, Blimp-1 recruited chromatin-remodeling and histone-modifying complexes to regulate its target genes. Hence, many essential functions of plasma cells are under the control of Blimp-1.
Assuntos
Diferenciação Celular/imunologia , Cadeias Pesadas de Imunoglobulinas/imunologia , Cadeias kappa de Imunoglobulina/imunologia , Fatores Reguladores de Interferon/imunologia , Plasmócitos/imunologia , Fatores de Transcrição/imunologia , Animais , Linfócitos B/imunologia , Linfócitos B/metabolismo , Adesão Celular/genética , Adesão Celular/imunologia , Diferenciação Celular/genética , Ensaios de Migração de Leucócitos , Movimento Celular/genética , Movimento Celular/imunologia , Imunoprecipitação da Cromatina , Ensaio de Desvio de Mobilidade Eletroforética , Ensaio de Imunoadsorção Enzimática , Citometria de Fluxo , Regulação da Expressão Gênica , Células HEK293 , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Cadeias Pesadas de Imunoglobulinas/genética , Cadeias kappa de Imunoglobulina/genética , Fatores Reguladores de Interferon/genética , Espectrometria de Massas , Camundongos , Plasmócitos/metabolismo , Fator 1 de Ligação ao Domínio I Regulador Positivo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Análise de Sequência de DNA , Análise de Sequência de RNA , Fatores de Transcrição/genéticaRESUMO
The proinflammatory cytokines interleukin 12 (IL-12) and IL-23 connect innate responses and adaptive immune responses and are also involved in autoimmune and inflammatory diseases. Here we describe an epigenetic mechanism for regulation of the genes encoding IL-12 (Il12a and Il12b; collectively called 'Il12' here) and IL-23 (Il23a and Il12b; collectively called 'Il23' here) involving the deubiquitinase Trabid. Deletion of Zranb1 (which encodes Trabid) in dendritic cells inhibited induction of the expression of Il12 and Il23 by Toll-like receptors (TLRs), which impaired the differentiation of inflammatory T cells and protected mice from autoimmune inflammation. Trabid facilitated TLR-induced histone modifications at the promoters of Il12 and Il23, which involved deubiqutination and stabilization of the histone demethylase Jmjd2d. Our findings highlight an epigenetic mechanism for the regulation of Il12 and Il23 and establish Trabid as an innate immunological regulator of inflammatory T cell responses.
Assuntos
Linfócitos T CD4-Positivos/imunologia , Células Dendríticas/imunologia , Encefalomielite Autoimune Experimental/genética , Epigênese Genética , Interleucina-12/genética , Interleucina-23/genética , Proteases Específicas de Ubiquitina/genética , Animais , Diferenciação Celular , Imunoprecipitação da Cromatina , Encefalomielite Autoimune Experimental/imunologia , Citometria de Fluxo , Regulação da Expressão Gênica , Técnicas de Silenciamento de Genes , Immunoblotting , Imunoprecipitação , Interleucina-12/imunologia , Interleucina-23/imunologia , Histona Desmetilases com o Domínio Jumonji/genética , Histona Desmetilases com o Domínio Jumonji/metabolismo , Camundongos , Proteínas de Ligação a RNA/genética , Proteínas de Ligação a RNA/imunologia , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transdução de Sinais , Receptores Toll-Like/metabolismo , Proteases Específicas de Ubiquitina/imunologia , Dedos de Zinco/genética , Dedos de Zinco/imunologiaRESUMO
Autoreactive B cells have critical roles in a large diversity of autoimmune diseases, but the molecular pathways that control these cells remain poorly understood. We performed an in vivo functional screen of a lymphocyte-expressed microRNA library and identified miR-148a as a potent regulator of B cell tolerance. Elevated miR-148a expression impaired B cell tolerance by promoting the survival of immature B cells after engagement of the B cell antigen receptor by suppressing the expression of the autoimmune suppressor Gadd45α, the tumor suppressor PTEN and the pro-apoptotic protein Bim. Furthermore, increased expression of miR-148a, which occurs frequently in patients with lupus and lupus-prone mice, facilitated the development of lethal autoimmune disease in a mouse model of lupus. Our studies demonstrate a function for miR-148a as a regulator of B cell tolerance and autoimmunity.
Assuntos
Apoptose/genética , Autoimunidade/genética , Linfócitos B/imunologia , Tolerância Imunológica/genética , MicroRNAs/genética , Animais , Apoptose/imunologia , Proteínas Reguladoras de Apoptose/metabolismo , Autoimunidade/imunologia , Proteína 11 Semelhante a Bcl-2 , Transplante de Medula Óssea , Proteínas de Ciclo Celular/metabolismo , Proliferação de Células/genética , Modelos Animais de Doenças , Células HEK293 , Humanos , Tolerância Imunológica/imunologia , Immunoblotting , Lúpus Eritematoso Sistêmico/imunologia , Proteínas de Membrana/metabolismo , Camundongos , Camundongos Endogâmicos MRL lpr , MicroRNAs/imunologia , Proteínas Nucleares/metabolismo , PTEN Fosfo-Hidrolase/metabolismo , Proteínas Proto-Oncogênicas/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Análise de Sequência de RNARESUMO
The gene encoding PTEN is one of the most frequently mutated tumor suppressor-encoding genes in human cancer. While PTEN's function in tumor suppression is well established, its relationship to anti-microbial immunity remains unknown. Here we found a pivotal role for PTEN in the induction of type I interferon, the hallmark of antiviral innate immunity, that was independent of the pathway of the kinases PI(3)K and Akt. PTEN controlled the import of IRF3, a master transcription factor responsible for IFN-ß production, into the nucleus. We further identified a PTEN-controlled negative phosphorylation site at Ser97 of IRF3 and found that release from this negative regulation via the phosphatase activity of PTEN was essential for the activation of IRF3 and its import into the nucleus. Our study identifies crosstalk between PTEN and IRF3 in tumor suppression and innate immunity.