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1.
Nat Immunol ; 20(9): 1244-1255, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31431722

RESUMO

Mucosal-associated invariant T cells (MAIT cells) recognize the microbial metabolite 5-(2-oxopropylideneamino)-6-D-ribitylaminouracil (5-OP-RU) presented by the MHC class Ib molecule, MR1. MAIT cells acquire effector functions during thymic development, but the mechanisms involved are unclear. Here we used single-cell RNA-sequencing to characterize the developmental path of 5-OP-RU-specific thymocytes. In addition to the known MAIT1 and MAIT17 effector subsets selected on bone-marrow-derived hematopoietic cells, we identified 5-OP-RU-specific thymocytes that were selected on thymic epithelial cells and differentiated into CD44- naive T cells. MAIT cell positive selection required signaling through the adapter, SAP, that controlled the expression of the transcription factor, ZBTB16. Pseudotemporal ordering of single cells revealed transcriptional trajectories of 5-OP-RU-specific thymocytes selected on either thymic epithelial cells or hematopoietic cells. The resulting model illustrates T cell lineage decisions.


Assuntos
Linhagem da Célula/imunologia , Células T Invariáveis Associadas à Mucosa/citologia , Células T Invariáveis Associadas à Mucosa/imunologia , Timócitos/citologia , Timócitos/imunologia , Animais , Sequência de Bases , Diferenciação Celular/genética , Diferenciação Celular/imunologia , Antígenos de Histocompatibilidade Classe I/metabolismo , Receptores de Hialuronatos/metabolismo , Ativação Linfocitária/imunologia , Camundongos , Camundongos Knockout , Antígenos de Histocompatibilidade Menor/metabolismo , Proteína com Dedos de Zinco da Leucemia Promielocítica/biossíntese , Receptores de Antígenos de Linfócitos T alfa-beta/imunologia , Análise de Sequência de RNA , Família de Moléculas de Sinalização da Ativação Linfocitária/metabolismo , Timo/citologia , Timo/imunologia
2.
Nature ; 571(7764): 265-269, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31207605

RESUMO

Cytotoxic T cells are essential mediators of protective immunity to viral infection and malignant tumours and are a key target of immunotherapy approaches. However, prolonged exposure to cognate antigens often attenuates the effector capacity of T cells and limits their therapeutic potential1-4. This process, known as T cell exhaustion or dysfunction1, is manifested by epigenetically enforced changes in gene regulation that reduce the expression of cytokines and effector molecules and upregulate the expression of inhibitory receptors such as programmed cell-death 1 (PD-1)5-8. The underlying molecular mechanisms that induce and stabilize the phenotypic and functional features of exhausted T cells remain poorly understood9-12. Here we report that the development and maintenance of populations of exhausted T cells in mice requires the thymocyte selection-associated high mobility group box (TOX) protein13-15. TOX is induced by high antigen stimulation of the T cell receptor and correlates with the presence of an exhausted phenotype during chronic infections with lymphocytic choriomeningitis virus in mice and hepatitis C virus in humans. Removal of its DNA-binding domain reduces the expression of PD-1 at the mRNA and protein level, augments the production of cytokines and results in a more polyfunctional T cell phenotype. T cells with this deletion initially mediate increased effector function and cause more severe immunopathology, but ultimately undergo a massive decline in their quantity, notably among the subset of TCF-1+ self-renewing T cells. Altogether, we show that TOX is a critical factor for the normal progression of T cell dysfunction and the maintenance of exhausted T cells during chronic infection, and provide a link between the suppression of effector function intrinsic to CD8 T cells and protection against immunopathology.


Assuntos
Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/patologia , Hepatite C Crônica/imunologia , Hepatite C Crônica/virologia , Proteínas de Grupo de Alta Mobilidade/metabolismo , Proteínas de Homeodomínio/metabolismo , Coriomeningite Linfocítica/imunologia , Coriomeningite Linfocítica/virologia , Animais , Proliferação de Células , Doença Crônica , Citocinas/imunologia , Citocinas/metabolismo , Epigênese Genética , Feminino , Regulação da Expressão Gênica/imunologia , Hepacivirus/imunologia , Fator 1-alfa Nuclear de Hepatócito/metabolismo , Humanos , Memória Imunológica , Vírus da Coriomeningite Linfocítica/imunologia , Masculino , Camundongos , Fenótipo , Timócitos/citologia , Timócitos/imunologia , Transcrição Genética
3.
Mol Immunol ; 112: 312-321, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31229844

RESUMO

Precise glycosylation plays a crucial and distinctive role in thymic T cell development. The core fucosylation is dramatically up-regulated at the transition from CD4-CD8- (DN) to CD4+CD8+ (DP) in the thymic development. Ablation of core fucosylation in T cells did reduce the size of the thymus due to a significant loss of CD4+ SP, CD8+ SP and DP thymocytes in core fucosyltransferase (Fut8) knockout (Fut8-/-) mice. T cell receptors (TCRs) are heavily core fucosylated glycoproteins. Loss of core fucosylation of TCR contributed to the reduced phosphorylation of ZAP70 (pZAP70) in Fut8-/- DP cells was observed. Compare to the Fut8+/+OT-II DP thymocytes, pZAP70 was significantly reduced in Fut8-/- OT-II DP thymocytes with OVA323-339 stimulation. Also, the pZAP70 of Fut8+/+OT-I DP thymocytes with OVA257-264 stimulation was remarkably attenuated by treatment of the fucosidase. Upon anti-CD3/CD28 Abs stimulation, the increased apoptosis was found in Fut8-/- thymocytes compared with Fut8+/+ thymocytes. Moreover, the TCRhiCD69hi (post-positive selection thymocytes) was markedly depleted in the Fut8-/- thymus without any stimulation. The expression of CD5 was significantly down-regulated on the DP cells in the Fut8-/- thymus. Our results therefore demonstrate that ablation of core fucosylation results in the abnormal T cell development due to the attenuated signaling via TCR.


Assuntos
Fucose/imunologia , Receptores de Antígenos de Linfócitos T/imunologia , Transdução de Sinais/imunologia , Linfócitos T/imunologia , Animais , Antígenos CD/imunologia , Antígenos de Diferenciação de Linfócitos T/imunologia , Apoptose/imunologia , Antígenos CD5/imunologia , Diferenciação Celular/imunologia , Fucosiltransferases/imunologia , Glicosilação , Lectinas Tipo C/imunologia , Ativação Linfocitária/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Fosforilação/imunologia , Timócitos/imunologia , Proteína-Tirosina Quinase ZAP-70/imunologia
4.
Nat Commun ; 10(1): 2220, 2019 05 17.
Artigo em Inglês | MEDLINE | ID: mdl-31101805

RESUMO

Both medullary thymic epithelial cells (mTEC) and dendritic cells (DC) present tissue-restricted antigens (TRA) to thymocytes to induce central tolerance, but the relative contributions of these antigen-presenting cell (APC) subsets remain unresolved. Here we developed a two-photon microscopy approach to observe thymocytes interacting with intact APCs presenting TRAs. We find that mTECs and DCs cooperate extensively to induce tolerance, with their relative contributions regulated by the cellular form of the TRA and the class of major histocompatibility complex (MHC) on which antigen is presented. Even when TRA expression is restricted to mTECs, DCs still present self-antigens at least as frequently as mTECs. Notably, the DC subset cDC2 efficiently acquires secreted mTEC-derived TRAs for cross-presentation on MHC-I. By directly imaging interactions between thymocytes and APCs, while monitoring intracellular signaling, this study reveals that distinct DC subsets and AIRE+ mTECs contribute substantially to presentation of diverse self-antigens for establishing central tolerance.


Assuntos
Tolerância Central/imunologia , Células Dendríticas/imunologia , Timócitos/imunologia , Timo/imunologia , Animais , Apresentação do Antígeno/imunologia , Autoantígenos/imunologia , Autoantígenos/metabolismo , Transplante de Medula Óssea , Separação Celular/métodos , Células Dendríticas/metabolismo , Células Epiteliais/imunologia , Feminino , Citometria de Fluxo/métodos , Microscopia Intravital/métodos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Microscopia de Fluorescência por Excitação Multifotônica/métodos , Linfócitos T Reguladores/imunologia , Timócitos/metabolismo , Timo/citologia , Fatores de Transcrição/imunologia , Fatores de Transcrição/metabolismo , Quimeras de Transplante/imunologia
5.
Genes Cells ; 24(7): 485-495, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31125466

RESUMO

Mammalian STE20-like protein kinase 1/2 (MST1/2) and nuclear Dbf2-related kinase 1/2 (NDR1/2) are core components of Hippo signaling that are also known to be important regulators of lymphocyte trafficking. However, little is understood about the roles of other Hippo pathway molecules in these cells. Here, we present the first analysis of the function of Mps one binder kinase activator-1 (MOB1) in T lymphocytes in vivo. T-cell-specific double knockout (DKO) of MOB1A/B in mice [tMob1 DKO mice] reduces the number of naïve T cells in both the circulation and secondary lymphoid organs, but leads to an accumulation of CD4+ CD8- and CD4- CD8+ single-positive (SP) cells in the thymus. In vitro, naïve MOB1A/B-deficient T cells show increased apoptosis and display impaired trafficking capacity in response to the chemokine CCL19. These defects are linked to suppression of the activation of MST and NDR kinases, but are independent of the downstream transcriptional co-activator Yes-associated protein 1 (YAP1). Thus, MOB1 proteins play an important role in thymic egress and T-cell survival that is mediated by a pathway other than conventional Hippo-YAP1 signaling.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Regulação da Expressão Gênica , Fosfoproteínas/metabolismo , Fosfoproteínas/fisiologia , Proteínas Quinases/fisiologia , Linfócitos T/imunologia , Timócitos/imunologia , Animais , Apoptose , Proteínas de Ciclo Celular , Células Cultivadas , Quimiotaxia , Feminino , Peptídeos e Proteínas de Sinalização Intracelular , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Linfócitos T/metabolismo , Linfócitos T/patologia , Timócitos/metabolismo , Timócitos/patologia
6.
Toxicol Lett ; 311: 49-57, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31014974

RESUMO

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD), the most toxic congener of dioxins, is a persistent and ubiquitous environmental contaminant. Although the immunotoxic effects of TCDD have been reported, the mechanisms underlying these effects are still unclear. In this study, we have determined the toxic effects of TCDD on thymocytes and splenic T cells with in vitro cell culture systems. Magnetically isolated mouse splenic Th cells, Treg cells and the mixed spleen lymphocytes (SLC) were cultured and treated with TCDD and the differentiation of CD4 Th cells was determined by flow cytometery. Our results showed that different concentrations of TCDD caused immunotoxic effects through different toxicological mechanisms in both the purified mouse splenic Th cells and the mixed SLC. The low dose exposure to TCDD triggered regulatory effects in the immune system, while the high dose TCDD exposure resulted in severe immune toxicity. Notably, a decline of Treg subset was observed, suggesting an imbalanced immune regulation by TCDD treatment, as well as a possible decrease of TCDD's indirect effects on bystander immune cells. Our CD4 Th subset co-culture experiments showed that TCDD-induced pathobiology depended on immune cell balance, suggesting that cytokine-induced microenvironments further modulated toxic effects associated with TCDD exposure.


Assuntos
Diferenciação Celular/efeitos dos fármacos , Poluentes Ambientais/toxicidade , Dibenzodioxinas Policloradas/toxicidade , Baço/efeitos dos fármacos , Linfócitos T Auxiliares-Indutores/efeitos dos fármacos , Timócitos/efeitos dos fármacos , Animais , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Proliferação de Células/efeitos dos fármacos , Células Cultivadas , Microambiente Celular , Técnicas de Cocultura , Citocinas/imunologia , Citocinas/metabolismo , Relação Dose-Resposta a Droga , Ativação Linfocitária/efeitos dos fármacos , Masculino , Camundongos Endogâmicos C57BL , Camundongos Knockout , Fenótipo , Receptores de Hidrocarboneto Arílico/genética , Receptores de Hidrocarboneto Arílico/metabolismo , Baço/imunologia , Baço/metabolismo , Linfócitos T Auxiliares-Indutores/imunologia , Linfócitos T Auxiliares-Indutores/metabolismo , Linfócitos T Reguladores/efeitos dos fármacos , Linfócitos T Reguladores/imunologia , Linfócitos T Reguladores/metabolismo , Timócitos/imunologia , Timócitos/metabolismo
7.
Biomed Res Int ; 2019: 4650695, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30906773

RESUMO

Purpose: Oxaliplatin is a platinum-based chemotherapeutic agent demonstrating significant antitumor efficacy. Unlike conventional anticancer agents which are immunosuppressive, oxaliplatin has the capacity to stimulate immunological effects in response to the presentation of damage associated molecular patterns (DAMPs) elicited upon cell death. However, the effects of oxaliplatin treatment on systemic immune responses remain largely unknown. Aims of this study were to investigate the effects of oxaliplatin treatment on the proportions of (1) splenic T cells, B cells, macrophages, pro-/anti-inflammatory cytokines, gene expression of splenic cytokines, chemokines, and mediators; (2) double-positive and single-positive CD4+ and CD8+ T thymocytes; (3) bone-marrow hematopoietic stem and progenitor cells. Methods: Male BALB/c mice received intraperitoneal injections of oxaliplatin (3mg/kg/d) or sterile water tri-weekly for 2 weeks. Leukocyte populations within the spleen, thymus, and bone-marrow were assessed using flow cytometry. RT-PCR was performed to characterise changes in splenic inflammation-associated genes. Results: Oxaliplatin treatment reduced spleen size and cellularity (CD45+ cells), increased the proportion of CD4+, CD8+, and Treg cells, and elevated TNF-α expression. Oxaliplatin was selectively cytotoxic to B cells but had no effect on splenic macrophages. Oxaliplatin treatment altered the gene expression of several cytokines, chemokines, and cell mediators. Oxaliplatin did not deplete double-positive thymocytes but increased the single-positive CD8+ subset. There was also an increase in activated (CD69+) CD8+ T cells. Bone-marrow hematopoietic progenitor pool was demonstrably normal following oxaliplatin treatment when compared to the vehicle-treated cohort. Conclusion: Oxaliplatin does not cause systemic immunosuppression and, instead, has the capacity to induce beneficial antitumor immune responses.


Assuntos
Tolerância Imunológica/efeitos dos fármacos , Imunidade Celular/efeitos dos fármacos , Neoplasias/tratamento farmacológico , Oxaliplatina/administração & dosagem , Animais , Células da Medula Óssea/efeitos dos fármacos , Células da Medula Óssea/imunologia , Linfócitos T CD4-Positivos/efeitos dos fármacos , Linfócitos T CD8-Positivos/efeitos dos fármacos , Quimiocinas/genética , Quimiocinas/imunologia , Citocinas/genética , Citocinas/imunologia , Expressão Gênica/efeitos dos fármacos , Expressão Gênica/imunologia , Células-Tronco Hematopoéticas/efeitos dos fármacos , Células-Tronco Hematopoéticas/imunologia , Humanos , Imunidade Celular/imunologia , Masculino , Camundongos Endogâmicos BALB C , Neoplasias/imunologia , Oxaliplatina/imunologia , Baço/efeitos dos fármacos , Linfócitos T Reguladores/efeitos dos fármacos , Linfócitos T Reguladores/imunologia , Timócitos/efeitos dos fármacos , Timócitos/imunologia
8.
Toxicol Lett ; 304: 30-38, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30605750

RESUMO

Clinical study showed that smoking during pregnancy deceased the thymus size in newborns. However, the long-term effect remains unclear. This study was aimed to observe the effects of prenatal nicotine exposure (PNE) on the development of thymus and the T-lymphocyte subpopulation in mice offspring from the neonatal to adulthood. Both the thymus weight and cytometry data indicated that PNE caused persistent thymic hypoplasia in male offspring from neonatal to adult period and transient changes in female offspring from neonatal to prepuberal period. Flow cytometry analysis disclosed a permanent decreased proportion and number of mature CD4 single-positive (SP) T cells in thymus of both sex. In addition, the PNE male offspring showed a more serious thymus atrophy in the ovalbumin (OVA)-sensitized model. Moreover, increased autophagic vacuole and elevated mRNA expression of Beclin 1 were noted in PNE fetal thymus. In conclusion, PNE offspring showed thymus atrophy and CD 4 SP T cell reduction at different life stages. Mechanically, PNE induced excessive autophagy in fetal thymocytes might be involved in these changes. All the results provided evidence for elucidating the PNE-induced programmed immune diseases.


Assuntos
Linfócitos T CD4-Positivos/efeitos dos fármacos , Doenças do Sistema Imunitário/induzido quimicamente , Nicotina/toxicidade , Agonistas Nicotínicos/toxicidade , Efeitos Tardios da Exposição Pré-Natal , Timócitos/efeitos dos fármacos , Timo/efeitos dos fármacos , Fatores Etários , Animais , Animais Recém-Nascidos , Autofagia/efeitos dos fármacos , Proteína Beclina-1/genética , Proteína Beclina-1/metabolismo , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD4-Positivos/metabolismo , Linfócitos T CD4-Positivos/patologia , Feminino , Doenças do Sistema Imunitário/imunologia , Doenças do Sistema Imunitário/metabolismo , Doenças do Sistema Imunitário/patologia , Masculino , Exposição Materna , Camundongos Endogâmicos BALB C , Ovalbumina/imunologia , Fenótipo , Gravidez , Timócitos/imunologia , Timócitos/metabolismo , Timócitos/patologia , Timo/imunologia , Timo/metabolismo , Timo/patologia
9.
J Immunol ; 202(3): 760-769, 2019 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-30567733

RESUMO

SRC3, a highly conserved member of the steroid receptor coactivator (SRC) family, is recruited by transcription factors to regulate cellular function. Previously, we demonstrated that SRC1, another highly conserved member of the SRC family, interacts with RORγt to regulate Th17 differentiation. However, the relationship between SRC1 and SRC3 in the regulation of Th17 cell function remains unknown. In this study, we demonstrate that mouse SRC3 interacts with RORγt in Th17 cells but not in thymocytes. In addition, Src3-/- mice exhibited defective Th17 differentiation and induction of experimental autoimmune encephalomyelitis but normal thymocyte development. Furthermore, a K313 to arginine mutation of RORγt (RORγt-K313R), which disrupts the interaction of RORγt with SRC3 but not with SRC1, impairs Th17 differentiation but not thymocyte development. These data suggest that SRC3 works with SRC1 to regulate RORγt-dependent Th17 differentiation but is not essential for RORγt-dependent thymocyte development.


Assuntos
Diferenciação Celular , Coativador 3 de Receptor Nuclear/genética , Membro 3 do Grupo F da Subfamília 1 de Receptores Nucleares/genética , Células Th17/imunologia , Timócitos/citologia , Animais , Encefalomielite Autoimune Experimental/imunologia , Regulação da Expressão Gênica , Ativação Linfocitária , Camundongos , Camundongos Knockout , Células Th17/citologia , Timócitos/imunologia
10.
Nat Commun ; 9(1): 5368, 2018 12 18.
Artigo em Inglês | MEDLINE | ID: mdl-30560927

RESUMO

Foxp3+CD4+ regulatory T (Treg) cells are essential for preventing fatal autoimmunity and safeguard immune homeostasis in vivo. While expression of the transcription factor Foxp3 and IL-2 signals are both required for the development and function of Treg cells, the commitment to the Treg cell lineage occurs during thymic selection upon T cell receptor (TCR) triggering, and precedes the expression of Foxp3. Whether signals beside TCR contribute to establish Treg cell epigenetic and functional identity is still unknown. Here, using a mouse model with reduced IL-2 signaling, we show that IL-2 regulates the positioning of the pioneer factor SATB1 in CD4+ thymocytes and controls genome wide chromatin accessibility of thymic-derived Treg cells. We also show that Treg cells receiving only low IL-2 signals can suppress endogenous but not WT autoreactive T cell responses in vitro and in vivo. Our findings have broad implications for potential therapeutic strategies to reprogram Treg cells in vivo.


Assuntos
Reprogramação Celular/genética , Epigênese Genética/imunologia , Interleucina-2/metabolismo , Proteínas de Ligação à Região de Interação com a Matriz/metabolismo , Linfócitos T Reguladores/imunologia , Animais , Autoimunidade/genética , Diferenciação Celular/imunologia , Reprogramação Celular/imunologia , Modelos Animais de Doenças , Feminino , Fatores de Transcrição Forkhead/imunologia , Fatores de Transcrição Forkhead/metabolismo , Células HEK293 , Humanos , Interleucina-2/imunologia , Subunidade alfa de Receptor de Interleucina-2/genética , Subunidade alfa de Receptor de Interleucina-2/imunologia , Subunidade alfa de Receptor de Interleucina-2/metabolismo , Listeriose/imunologia , Listeriose/microbiologia , Masculino , Proteínas de Ligação à Região de Interação com a Matriz/genética , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Transdução de Sinais/genética , Transdução de Sinais/imunologia , Linfócitos T Reguladores/metabolismo , Timócitos/imunologia , Timócitos/metabolismo , Timócitos/fisiologia , Timo/citologia
11.
Einstein (Sao Paulo) ; 16(4): eAO4278, 2018 Nov 29.
Artigo em Inglês, Português | MEDLINE | ID: mdl-30517367

RESUMO

OBJECTIVE: To investigate the correlation between total lymphocyte and CD3+ T cell counts in peripheral blood in renal transplant patients treated with anti-thymocyte globulin, and discuss related outcomes. METHODS: A single-center, retrospective study involving 226 patients submitted to kidney transplant between 2008 and 2013, and treated with anti-thymocyte globulin for induction or treatment of cellular rejection. Doses were adjusted according to CD3+ T cell or total lymphocyte counts in peripheral blood. RESULTS: A total of 664 paired samples were analyzed. The Spearman's correlation coefficient was 0.416 (p<0.001) for all samples combined; the overall Kappa coefficient was 0.267 (p<0.001). Diagnostic parameters estimated based on total lymphocyte counts were also calculated using the number of CD3+ T cells (gold standard), with a cut off of >20 cells/mm3. CONCLUSION: Total lymphocyte and CD3+ T cell counts in peripheral blood are not equivalent monitoring strategies in anti-thymocyte globulin therapy.


Assuntos
Anticorpos Monoclonais/uso terapêutico , Complexo CD3 , Rejeição de Enxerto/terapia , Isoanticorpos/uso terapêutico , Transplante de Rim , Timócitos/imunologia , Transplantados , Adulto , Feminino , Citometria de Fluxo/métodos , Humanos , Imunoterapia/métodos , Contagem de Linfócitos , Masculino , Pessoa de Meia-Idade , Monitorização Imunológica/instrumentação , Estudos Retrospectivos , Análise de Sobrevida , Linfócitos T/imunologia
12.
Int J Rheum Dis ; 21(12): 2071-2078, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30556363

RESUMO

AIM: Allergy inhibitory receptor-1 (Allergin-1) is a newly identified immune regulatory molecule thought to influence autoantibody production. Autoantibody production, like that observed in Allergin-1-deficient mice, is crucial in the pathogenesis of several autoimmune diseases such as systemic lupus erythematosus. The purpose of this study is to clarify the regulatory role of Allergin-1-mediated autoantibody production using a murine model of thymocytic anaphylaxis. METHODS: C57BL/6 (WT) and Allergin-1-deficient mice were treated with apoptotic cells from naive thymocytes stimulated by dexamethasone. Antibody titers of total or immunoglobulin G (IgG) subclass of anti-double-stranded DNA (anti-dsDNA) and anti-histone antibody from serum were measured using an enzyme-linked immunosorbent assay. Macrophages from wild-type (WT) or Allergin-1-deficient mice were co-cultured with fluorescence-labeled apoptotic thymocytes or fluorogenic reagent and resultant phagocytic activity was quantified by with flow cytometry. RESULTS: After apoptotic cells injection, antibody titers of total and IgG3 anti-dsDNA and total anti-histone from serum were significantly increased in Allergin-1-deficient versus WT mice. Phagocytic activity was significantly lower in macrophages from Allergin-1-deficient mice versus WT mice. CONCLUSION: Allergin-1 might play an inhibitory role in autoantibody production via upregulation of macrophage phagocytosis.


Assuntos
Anafilaxia/imunologia , Apoptose , Autoanticorpos/imunologia , Macrófagos/imunologia , Fagocitose , Receptores Imunológicos/metabolismo , Timócitos/imunologia , Anafilaxia/genética , Anafilaxia/metabolismo , Anafilaxia/patologia , Animais , Autoanticorpos/sangue , Células Cultivadas , Técnicas de Cocultura , Modelos Animais de Doenças , Feminino , Macrófagos/metabolismo , Camundongos Endogâmicos C57BL , Camundongos Knockout , Receptores Imunológicos/deficiência , Receptores Imunológicos/genética , Timócitos/patologia
13.
J R Soc Interface ; 15(148)2018 11 07.
Artigo em Inglês | MEDLINE | ID: mdl-30404905

RESUMO

The thymus is the primary organ for the generation of naive T cells, a key component of the immune system. Tolerance of T cells to self is achieved primarily in the thymic medulla, where immature T cells (thymocytes) sample self-peptides presented by medullary thymic epithelial cells (mTECs). A sufficiently strong interaction activates the thymocytes leading to negative selection. A key question of current interest is whether there is any structure in the manner in which mTECs present peptides: can any mTEC present any peptide at any time, or are there particular patterns of correlated peptide presentation? We investigate this question using a mathematical model of negative selection. We find that correlated patterns of peptide presentation may be advantageous in negatively selecting low-degeneracy thymocytes (that is, those thymocytes which respond to relatively few peptides). We also quantify the probability that an auto-reactive thymocyte exits the thymus before it encounters a cognate antigen. The results suggest that heterogeneity of gene co-expression in mTECs has an effect on the probability of escape of autoreactive thymocytes.


Assuntos
Apresentação do Antígeno , Seleção Clonal Mediada por Antígeno , Modelos Imunológicos , Timócitos/imunologia , Timo/imunologia , Animais , Peptídeos/imunologia , Timo/citologia
14.
Nat Immunol ; 19(12): 1366-1378, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30420627

RESUMO

Thymocyte development requires a complex orchestration of multiple transcription factors. Ablating either TCF-1 or HEB in CD4+CD8+ thymocytes elicits similar developmental outcomes including increased proliferation, decreased survival, and fewer late Tcra rearrangements. Here, we provide a mechanistic explanation for these similarities by showing that TCF-1 and HEB share ~7,000 DNA-binding sites genome wide and promote chromatin accessibility. The binding of both TCF-1 and HEB was required at these shared sites for epigenetic and transcriptional gene regulation. Binding of TCF-1 and HEB to their conserved motifs in the enhancer regions of genes associated with T cell differentiation promoted their expression. Binding to sites lacking conserved motifs in the promoter regions of cell-cycle-associated genes limited proliferation. TCF-1 displaced nucleosomes, allowing for chromatin accessibility. Importantly, TCF-1 inhibited Notch signaling and consequently protected HEB from Notch-mediated proteasomal degradation. Thus, TCF-1 shifts nucleosomes and safeguards HEB, thereby enabling their cooperation in establishing the epigenetic and transcription profiles of CD4+CD8+ thymocytes.


Assuntos
Fatores de Transcrição Hélice-Alça-Hélice Básicos/imunologia , Regulação da Expressão Gênica/imunologia , Fator 1-alfa Nuclear de Hepatócito/imunologia , Linfopoese/imunologia , Timócitos/imunologia , Animais , Antígenos CD4/imunologia , Antígenos CD8/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos
15.
Nat Immunol ; 19(12): 1379-1390, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30420628

RESUMO

The T cell antigen receptor (TCR) expressed on thymocytes interacts with self-peptide major histocompatibility complex (pMHC) ligands to signal apoptosis or survival. Here, we found that negative-selection ligands induced thymocytes to exert forces on the TCR and the co-receptor CD8 and formed cooperative TCR-pMHC-CD8 trimolecular 'catch bonds', whereas positive-selection ligands induced less sustained thymocyte forces on TCR and CD8 and formed shorter-lived, independent TCR-pMHC and pMHC-CD8 bimolecular 'slip bonds'. Catch bonds were not intrinsic to either the TCR-pMHC or the pMHC-CD8 arm of the trans (cross-junctional) heterodimer but resulted from coupling of the extracellular pMHC-CD8 interaction to the intracellular interaction of CD8 with TCR-CD3 via associated kinases to form a cis (lateral) heterodimer capable of inside-out signaling. We suggest that the coupled trans-cis heterodimeric interactions form a mechanotransduction loop that reinforces negative-selection signaling that is distinct from positive-selection signaling in the thymus.


Assuntos
Mecanotransdução Celular/imunologia , Receptores de Antígenos de Linfócitos T/imunologia , Timócitos/imunologia , Timo/imunologia , Animais , Deleção Clonal/imunologia , Camundongos , Camundongos Transgênicos , Receptores de Antígenos de Linfócitos T/metabolismo , Timócitos/metabolismo
16.
J Exp Med ; 215(12): 2984-2993, 2018 12 03.
Artigo em Inglês | MEDLINE | ID: mdl-30425120

RESUMO

The emigration of mature thymocytes from the thymus is critical for establishing peripheral T cell compartments. However, the pathways controlling this process and the timing of egress in relation to postselection developmental stages are poorly defined. Here, we reexamine thymocyte egress and test current and opposing models in relation to the requirement for LTßR, a regulator of thymic microenvironments and thymocyte emigration. Using cell-specific gene targeting, we show that the requirement for LTßR in thymocyte egress is distinct from its control of thymic epithelium and instead maps to expression by endothelial cells. By separating emigration into sequential phases of perivascular space (PVS) entry and transendothelial migration, we reveal a developmentally ordered program of egress where LTßR operates to rate limit access to the PVS. Collectively, we show the process of thymic emigration ensures only the most mature thymocytes leave the thymus and demonstrate a role for LTßR in the initiation of thymus emigration that segregates from its control of medulla organization.


Assuntos
Movimento Celular/imunologia , Células Endoteliais/imunologia , Receptor beta de Linfotoxina/imunologia , Timócitos/imunologia , Timo/imunologia , Animais , Movimento Celular/genética , Células Endoteliais/citologia , Receptor beta de Linfotoxina/genética , Camundongos , Camundongos Knockout , Timócitos/citologia , Timo/citologia
17.
Nat Commun ; 9(1): 4870, 2018 11 19.
Artigo em Inglês | MEDLINE | ID: mdl-30451821

RESUMO

RORγt controls the differentiation of TH17 cells, which are mediators of autoimmune conditions such as experimental autoimmune encephalomyelitis (EAE). RORγt also regulates thymocyte development and lymph node genesis. Here we show that the function of RORγt is regulated by its sumoylation. Loss of Sumo3, but not Sumo1, dampens TH17 differentiation and delays the progression of thymic CD8+ immature single-positive cells (ISPs). RORγt is SUMO3-modified by E3 ligase PIAS4 at lysine 31 (K31), and the mutation of K31 to arginine in mice prevents RORγt sumoylation, leading to impaired TH17 differentiation, resistance to TH17-mediated EAE, accumulation of thymic ISPs, and a lack of Peyer's patches. Mechanistically, sumoylation of RORγt-K31 recruits histone acetyltransferase KAT2A, which stabilizes the binding of SRC1 to enhance RORγt transcription factor activity. This study thus demonstrates that sumoylation is a critical mechanism for regulating RORγt function, and reveals new drug targets for preventing TH17-mediated autoimmunity.


Assuntos
Encefalomielite Autoimune Experimental/genética , Membro 3 do Grupo F da Subfamília 1 de Receptores Nucleares/genética , Processamento de Proteína Pós-Traducional , Células Th17/imunologia , Timócitos/microbiologia , Timo/imunologia , Ubiquitinas/genética , Animais , Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/patologia , Diferenciação Celular , Encefalomielite Autoimune Experimental/imunologia , Encefalomielite Autoimune Experimental/patologia , Feminino , Hematopoese/genética , Hematopoese/imunologia , Linfonodos/imunologia , Linfonodos/patologia , Masculino , Camundongos , Camundongos Transgênicos , Coativador 1 de Receptor Nuclear/genética , Coativador 1 de Receptor Nuclear/imunologia , Membro 3 do Grupo F da Subfamília 1 de Receptores Nucleares/imunologia , Nódulos Linfáticos Agregados/imunologia , Nódulos Linfáticos Agregados/patologia , Proteína SUMO-1/deficiência , Proteína SUMO-1/genética , Proteína SUMO-1/imunologia , Sumoilação , Células Th17/patologia , Timócitos/imunologia , Timócitos/patologia , Timo/patologia , Ubiquitinas/deficiência , Ubiquitinas/imunologia , Fatores de Transcrição de p300-CBP/genética , Fatores de Transcrição de p300-CBP/imunologia
18.
Front Immunol ; 9: 2426, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30483245

RESUMO

Functional antigen receptor genes are assembled by somatic rearrangements that are largely lymphocyte lineage specific. The immunoglobulin heavy chain (IgH) gene locus is unique amongst the seven antigen receptor loci in undergoing partial gene rearrangements in the wrong lineage. Here we demonstrate that breakdown of lineage-specificity is associated with inappropriate activation of the Eµ enhancer during T cell development by a different constellation of transcription factors than those used in developing B cells. This is reflected in reduced enhancer-induced epigenetic changes, eRNAs, formation of the RAG1/2-rich recombination center, attenuated chromatin looping and markedly different utilization of DH gene segments in CD4+CD8+ (DP) thymocytes. Additionally, CTCF-dependent VH locus compaction is disrupted in DP cells despite comparable transcription factor binding in both lineages. These observations identify multiple mechanisms that contribute to lineage-specific antigen receptor gene assembly.


Assuntos
Regulação da Expressão Gênica , Loci Gênicos , Cadeias Pesadas de Imunoglobulinas/genética , Timócitos/imunologia , Timócitos/metabolismo , Animais , Linfócitos B/imunologia , Linfócitos B/metabolismo , Cromatina/genética , Elementos Facilitadores Genéticos , Íntrons , Camundongos , Curva ROC , Timócitos/citologia , Recombinação V(D)J
19.
J Exp Med ; 215(11): 2887-2900, 2018 11 05.
Artigo em Inglês | MEDLINE | ID: mdl-30287480

RESUMO

Natural killer T (NKT) cells expressing the invariant T cell receptor (iTCR) serve an essential function in clearance of certain pathogens and have been implicated in autoimmune and allergic diseases. Complex effector programs of these iNKT cells are wired in the thymus, and upon thymic egress, they can respond within hours of antigenic challenges, classifying iNKT cells as innate-like. It has been assumed that the successful rearrangement of the invariant iTCRα chain is the central event in the divergence of immature thymocytes to the NKT cell lineage, but molecular properties that render the iTCR signaling distinct to permit the T cell lineage diversification remain obscure. Here we show that the High Mobility Group (HMG) transcription factor (TF) SOX4 controls the production of iNKT cells by inducing MicroRNA-181 (Mir181) to enhance TCR signaling and Ca2+ fluxes in precursors. These results suggest the existence of tailored, permissive gene circuits in iNKT precursors for innate-like T cell development.


Assuntos
Sinalização do Cálcio/imunologia , MicroRNAs/imunologia , Células T Matadoras Naturais/imunologia , Receptores de Antígenos de Linfócitos T/imunologia , Fatores de Transcrição SOXC/imunologia , Timócitos/imunologia , Animais , Sinalização do Cálcio/genética , Rearranjo Gênico do Linfócito T/imunologia , Camundongos , Camundongos Knockout , MicroRNAs/genética , Células T Matadoras Naturais/citologia , Receptores de Antígenos de Linfócitos T/genética , Fatores de Transcrição SOXC/genética , Timócitos/citologia
20.
Front Immunol ; 9: 2335, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30369926

RESUMO

Multiple sclerosis (MS) is a chronic, immune-mediated, demyelinating disease that affects the neurons of the central nervous system. Activated T cells, specific for myelin epitopes, cross the brain barriers, and react against the myelin sheath, leading to demyelination. Since T cells are generated within the thymus, here we explored, in mice, the alterations occurring in this organ throughout the different phases of the disease. We induced experimental autoimmune encephalomyelitis (EAE) in C57BL/6 females and sacrifice them at the onset (day 16) and chronic phases of disease (day 23), along with non-induced controls. We observed thymic atrophy in EAE mice at the onset that remained until the chronic phase of disease. This atrophy was associated with a preferential loss of the CD4+CD8+ double positive thymocytes, an intermediate population between the more immature CD4-CD8- double negative and the most mature single positive thymocytes. This was accompanied by an increase in the thymic medullary/cortical ratio and by an altered expression levels of genes important for T cell survival. During the chronic phase, the thymi remained atrophic, but reacquired the normal proportion of the main four thymocyte populations and the normal medullary/cortical ratio. Importantly, at the onset phase, and accompanying these thymic alterations, EAE animals presented an increased percentage of demyelinating lesion area in the cerebellum, and an increased expression of interferon gamma (Ifng), interleukin (Il) 12a, and Il17a. This study suggests dynamic thymic alterations occurring in response to EAE, from the induction to the chronic phase, that might help to elucidate the MS pathophysiology.


Assuntos
Autoimunidade , Imunidade , Glicoproteína Mielina-Oligodendrócito/imunologia , Timo/imunologia , Animais , Atrofia , Biomarcadores , Diferenciação Celular/imunologia , Cerebelo/imunologia , Cerebelo/metabolismo , Cerebelo/patologia , Citocinas/metabolismo , Modelos Animais de Doenças , Encefalomielite Autoimune Experimental/imunologia , Feminino , Expressão Gênica , Imunofenotipagem , Mediadores da Inflamação/metabolismo , Camundongos , Esclerose Múltipla/imunologia , Esclerose Múltipla/metabolismo , Esclerose Múltipla/patologia , Timócitos/imunologia , Timócitos/metabolismo , Timo/metabolismo , Timo/patologia
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