RESUMO
The thymus is essential for establishing adaptive immunity yet undergoes age-related involution that leads to compromised immune responsiveness. The thymus is also extremely sensitive to acute insult and although capable of regeneration, this capacity declines with age for unknown reasons. We applied single-cell and spatial transcriptomics, lineage-tracing and advanced imaging to define age-related changes in nonhematopoietic stromal cells and discovered the emergence of two atypical thymic epithelial cell (TEC) states. These age-associated TECs (aaTECs) formed high-density peri-medullary epithelial clusters that were devoid of thymocytes; an accretion of nonproductive thymic tissue that worsened with age, exhibited features of epithelial-to-mesenchymal transition and was associated with downregulation of FOXN1. Interaction analysis revealed that the emergence of aaTECs drew tonic signals from other functional TEC populations at baseline acting as a sink for TEC growth factors. Following acute injury, aaTECs expanded substantially, further perturbing trophic regeneration pathways and correlating with defective repair of the involuted thymus. These findings therefore define a unique feature of thymic involution linked to immune aging and could have implications for developing immune-boosting therapies in older individuals.
RESUMO
Group 2 innate lymphoid cells (ILC2s) are essential to maintain tissue homeostasis. In cancer, ILC2s can harbor both pro-tumorigenic and anti-tumorigenic functions, but we know little about their underlying mechanisms or whether they could be clinically relevant or targeted to improve patient outcomes. Here, we found that high ILC2 infiltration in human melanoma was associated with a good clinical prognosis. ILC2s are critical producers of the cytokine granulocyte-macrophage colony-stimulating factor, which coordinates the recruitment and activation of eosinophils to enhance antitumor responses. Tumor-infiltrating ILC2s expressed programmed cell death protein-1, which limited their intratumoral accumulation, proliferation and antitumor effector functions. This inhibition could be overcome in vivo by combining interleukin-33-driven ILC2 activation with programmed cell death protein-1 blockade to significantly increase antitumor responses. Together, our results identified ILC2s as a critical immune cell type involved in melanoma immunity and revealed a potential synergistic approach to harness ILC2 function for antitumor immunotherapies.
Assuntos
Anticorpos/farmacologia , Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Inibidores de Checkpoint Imunológico/farmacologia , Interleucina-33/farmacologia , Linfócitos/efeitos dos fármacos , Melanoma Experimental/tratamento farmacológico , Receptor de Morte Celular Programada 1/antagonistas & inibidores , Neoplasias Cutâneas/tratamento farmacológico , Animais , Linhagem Celular Tumoral , Quimiotaxia de Leucócito/efeitos dos fármacos , Citotoxicidade Imunológica/efeitos dos fármacos , Eosinófilos/efeitos dos fármacos , Eosinófilos/imunologia , Eosinófilos/metabolismo , Feminino , Fator Estimulador de Colônias de Granulócitos e Macrófagos/genética , Fator Estimulador de Colônias de Granulócitos e Macrófagos/metabolismo , Humanos , Linfócitos/imunologia , Linfócitos/metabolismo , Masculino , Melanoma Experimental/genética , Melanoma Experimental/imunologia , Melanoma Experimental/metabolismo , Camundongos Endogâmicos C57BL , Camundongos Knockout , Fenótipo , Receptor de Morte Celular Programada 1/genética , Receptor de Morte Celular Programada 1/metabolismo , Neoplasias Cutâneas/genética , Neoplasias Cutâneas/imunologia , Neoplasias Cutâneas/metabolismoRESUMO
The detection of aberrant cells by natural killer (NK) cells is controlled by the integration of signals from activating and inhibitory ligands and from cytokines such as IL-15. We identified cytokine-inducible SH2-containing protein (CIS, encoded by Cish) as a critical negative regulator of IL-15 signaling in NK cells. Cish was rapidly induced in response to IL-15, and deletion of Cish rendered NK cells hypersensitive to IL-15, as evidenced by enhanced proliferation, survival, IFN-γ production and cytotoxicity toward tumors. This was associated with increased JAK-STAT signaling in NK cells in which Cish was deleted. Correspondingly, CIS interacted with the tyrosine kinase JAK1, inhibiting its enzymatic activity and targeting JAK for proteasomal degradation. Cish(-/-) mice were resistant to melanoma, prostate and breast cancer metastasis in vivo, and this was intrinsic to NK cell activity. Our data uncover a potent intracellular checkpoint in NK cell-mediated tumor immunity and suggest possibilities for new cancer immunotherapies directed at blocking CIS function.
Assuntos
Imunoterapia/métodos , Células Matadoras Naturais/imunologia , Neoplasias/terapia , Proteínas Supressoras da Sinalização de Citocina/metabolismo , Animais , Proliferação de Células/genética , Citotoxicidade Imunológica/genética , Vigilância Imunológica , Interferon gama/metabolismo , Interleucina-15/metabolismo , Janus Quinase 1/metabolismo , Ativação Linfocitária/genética , Melanoma Experimental , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Terapia de Alvo Molecular , Neoplasias/imunologia , Transdução de Sinais/genética , Proteínas Supressoras da Sinalização de Citocina/genéticaRESUMO
Foxp3⺠regulatory T (Treg) cells are a crucial immunosuppressive population of CD4⺠T cells, yet the homeostatic processes and survival programs that maintain the Treg cell pool are poorly understood. Here we report that peripheral Treg cells markedly alter their proliferative and apoptotic rates to rapidly restore numerical deficit through an interleukin 2-dependent and costimulation-dependent process. By contrast, excess Treg cells are removed by attrition, dependent on the Bim-initiated Bak- and Bax-dependent intrinsic apoptotic pathway. The antiapoptotic proteins Bcl-xL and Bcl-2 were dispensable for survival of Treg cells, whereas Mcl-1 was critical for survival of Treg cells, and the loss of this antiapoptotic protein caused fatal autoimmunity. Together, these data define the active processes by which Treg cells maintain homeostasis via critical survival pathways.
Assuntos
Apoptose/imunologia , Fatores de Transcrição Forkhead/metabolismo , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Linfócitos T Reguladores/imunologia , Linfócitos T Reguladores/metabolismo , Animais , Apoptose/genética , Sobrevivência Celular/genética , Sobrevivência Celular/imunologia , Feminino , Fatores de Transcrição Forkhead/genética , Deleção de Genes , Homeostase/imunologia , Interleucina-2/metabolismo , Contagem de Linfócitos , Masculino , Camundongos , Camundongos Knockout , Proteína de Sequência 1 de Leucemia de Células Mieloides , Proteínas Proto-Oncogênicas c-bcl-2/genética , Transdução de SinaisRESUMO
Immunological tolerance is established and maintained by a diverse array of safeguards that work together to protect against autoimmunity. Despite the identification of numerous tolerogenic processes, the basis for cooperation among them remains poorly understood. We sought to identify synergy among several well-defined tolerance mediators that alone provide protection only from mild autoimmune symptoms in C57BL/6 mice: BIM, AIRE, CBL-B, and PD-1. Survey of a range of compound mutant mice revealed that the combined loss of the autoimmune regulator, AIRE, with PD-1 unleashed a spontaneous, lethal autoimmune disease. Pdcd1−/−Aire−/− mice succumbed to cachexia before adulthood, with near-complete destruction of the exocrine pancreas. Such fatal autoimmunity was not observed in Pdcd1−/−Bim−/−, Bim−/−Aire−/−, or Cblb−/−Bim−/− mice, suggesting that the cooperation between AIRE-mediated and PD-1mediated tolerance was particularly potent. Immune profiling revealed largely normal development of FOXP3+ regulatory T (Treg) cells in Pdcd1−/−Aire−/− mice, yet excessive, early activation of effector T cells. Adoptive transfer experiments demonstrated that autoimmune exocrine pancreatitis was driven by conventional CD4+ T cells and could not be prevented by the cotransfer of Treg cells from wild-type mice. The development of autoimmunity in mixed bone marrow chimeras supported these observations, indicating that failure of recessive tolerance was responsible for disease. These findings reveal a potent tolerogenic axis between AIRE and PD-1 that has implications for our understanding of how immune checkpoint blockade might synergize with subclinical defects in central tolerance to elicit autoimmune disease.
Assuntos
Pancreatite Autoimune , Tolerância Imunológica , Tolerância Periférica , Receptor de Morte Celular Programada 1 , Fatores de Transcrição , Animais , Pancreatite Autoimune/genética , Pancreatite Autoimune/imunologia , Autoimunidade/genética , Tolerância Imunológica/genética , Camundongos , Camundongos Endogâmicos C57BL , Tolerância Periférica/genética , Tolerância Periférica/imunologia , Receptor de Morte Celular Programada 1/genética , Receptor de Morte Celular Programada 1/fisiologia , Timo/imunologia , Fatores de Transcrição/genética , Fatores de Transcrição/fisiologia , Proteína AIRERESUMO
Venetoclax (VEN) inhibits the prosurvival protein BCL2 to induce apoptosis and is a standard therapy for chronic lymphocytic leukemia (CLL), delivering high complete remission rates and prolonged progression-free survival in relapsed CLL but with eventual loss of efficacy. A spectrum of subclonal genetic changes associated with VEN resistance has now been described. To fully understand clinical resistance to VEN, we combined single-cell short- and long-read RNA-sequencing to reveal the previously unappreciated scale of genetic and epigenetic changes underpinning acquired VEN resistance. These appear to be multilayered. One layer comprises changes in the BCL2 family of apoptosis regulators, especially the prosurvival family members. This includes previously described mutations in BCL2 and amplification of the MCL1 gene but is heterogeneous across and within individual patient leukemias. Changes in the proapoptotic genes are notably uncommon, except for single cases with subclonal losses of BAX or NOXA. Much more prominent was universal MCL1 gene upregulation. This was driven by an overlying layer of emergent NF-κB (nuclear factor kappa B) activation, which persisted in circulating cells during VEN therapy. We discovered that MCL1 could be a direct transcriptional target of NF-κB. Both the switch to alternative prosurvival factors and NF-κB activation largely dissipate following VEN discontinuation. Our studies reveal the extent of plasticity of CLL cells in their ability to evade VEN-induced apoptosis. Importantly, these findings pinpoint new approaches to circumvent VEN resistance and provide a specific biological justification for the strategy of VEN discontinuation once a maximal response is achieved rather than maintaining long-term selective pressure with the drug.
Assuntos
Antineoplásicos , Leucemia Linfocítica Crônica de Células B , Humanos , Leucemia Linfocítica Crônica de Células B/tratamento farmacológico , Leucemia Linfocítica Crônica de Células B/genética , Leucemia Linfocítica Crônica de Células B/metabolismo , Proteína de Sequência 1 de Leucemia de Células Mieloides/metabolismo , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , NF-kappa B , Resistencia a Medicamentos Antineoplásicos/genética , Compostos Bicíclicos Heterocíclicos com Pontes/farmacologia , Compostos Bicíclicos Heterocíclicos com Pontes/uso terapêutico , Recidiva , Antineoplásicos/uso terapêuticoRESUMO
Due to the myriad interactions between prosurvival and proapoptotic members of the Bcl-2 family of proteins, establishing the mechanisms that regulate the intrinsic apoptotic pathway has proven challenging. Mechanistic insights have primarily been gleaned from in vitro studies because genetic approaches in mammals that produce unambiguous data are difficult to design. Here we describe a mutation in mouse and human Bak that specifically disrupts its interaction with the prosurvival protein Bcl-xL Substitution of Glu75 in mBak (hBAK Q77) for leucine does not affect the three-dimensional structure of Bak or killing activity but reduces its affinity for Bcl-xL via loss of a single hydrogen bond. Using this mutant, we investigated the requirement for physical restraint of Bak by Bcl-xL in apoptotic regulation. In vitro, Bak(Q75L) cells were significantly more sensitive to various apoptotic stimuli. In vivo, loss of Bcl-xL binding to Bak led to significant defects in T-cell and blood platelet survival. Thus, we provide the first definitive in vivo evidence that prosurvival proteins maintain cellular viability by interacting with and inhibiting Bak.
Assuntos
Apoptose/genética , Plaquetas/citologia , Linfócitos T/citologia , Proteína Killer-Antagonista Homóloga a bcl-2/metabolismo , Proteína bcl-X/metabolismo , Animais , Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Plaquetas/efeitos dos fármacos , Plaquetas/metabolismo , Linhagem Celular , Sobrevivência Celular/genética , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Mutação , Ligação Proteica , Conformação Proteica , Domínios Proteicos/genética , Linfócitos T/efeitos dos fármacos , Linfócitos T/metabolismo , Proteína Killer-Antagonista Homóloga a bcl-2/genéticaRESUMO
Thymic output is a dynamic process, with high activity at birth punctuated by transient periods of involution during infection. Interferon-α (IFN-α) is a critical molecular mediator of pathogen-induced thymic involution, yet despite the importance of thymic involution, relatively little is known about the molecular integrators that establish sensitivity. Here we found that the microRNA network dependent on the endoribonuclease Dicer, and specifically microRNA miR-29a, was critical for diminishing the sensitivity of the thymic epithelium to simulated infection signals, protecting the thymus against inappropriate involution. In the absence of Dicer or the miR-29a cluster in the thymic epithelium, expression of the IFN-α receptor by the thymic epithelium was higher, which allowed suboptimal signals to trigger rapid loss of thymic cellularity.
Assuntos
RNA Helicases DEAD-box/imunologia , MicroRNAs/imunologia , Receptor de Interferon alfa e beta/imunologia , Ribonuclease III/imunologia , Timo/imunologia , Animais , Artrite/genética , Artrite/imunologia , RNA Helicases DEAD-box/genética , Feminino , Fatores de Transcrição Forkhead/genética , Fatores de Transcrição Forkhead/imunologia , Masculino , Camundongos , Ribonuclease III/genética , Timo/citologiaRESUMO
T cell development occurs in the thymus, where uncommitted progenitors are directed into a range of sublineages with distinct functions. The goal is to generate a TCR repertoire diverse enough to recognize potential pathogens while remaining tolerant of self. Decades of intensive research have characterized the transcriptional programs controlling critical differentiation checkpoints at the population level. However, greater precision regarding how and when these programs orchestrate differentiation at the single-cell level is required. Single-cell RNA sequencing approaches are now being brought to bear on this question, to track the identity of cells and analyze their gene expression programs at a resolution not previously possible. In this review, we discuss recent advances in the application of these technologies that have the potential to yield unprecedented insight to T cell development.
Assuntos
Diferenciação Celular/imunologia , Linfócitos T/imunologia , Animais , Humanos , Análise de Sequência de RNA/métodos , Timo/imunologiaRESUMO
MHC class II (MHC II) displays peptides at the cell surface, a process critical for CD4+ T cell development and priming. Ubiquitination is a mechanism that dictates surface MHC II with the attachment of a polyubiquitin chain to peptide-loaded MHC II, promoting its traffic away from the plasma membrane. In this study, we have examined how MHC II ubiquitination impacts the composition and function of both conventional CD4+ T cell and regulatory T cell (Treg) compartments. Responses were examined in two models of altered MHC II ubiquitination: MHCIIKRKI /KI mice that express a mutant MHC II unable to be ubiquitinated or mice that lack membrane-associated RING-CH 8 (MARCH8), the E3 ubiquitin ligase responsible for MHC II ubiquitination specifically in thymic epithelial cells. Conventional CD4+ T cell populations in thymus, blood, and spleen of MHCIIKRKI/KI and March8 -/- mice were largely unaltered. In MLRs, March8 -/-, but not MHCIIKRKI/KI, CD4+ T cells had reduced reactivity to both self- and allogeneic MHC II. Thymic Treg were significantly reduced in MHCIIKRKI/KI mice, but not March8 -/- mice, whereas splenic Treg were unaffected. Neither scenario provoked autoimmunity, with no evidence of immunohistopathology and normal levels of autoantibody. In summary, MHC II ubiquitination in specific APC types does not have a major impact on the conventional CD4+ T cell compartment but is important for Treg development.
Assuntos
Linfócitos T CD4-Positivos/imunologia , Antígenos de Histocompatibilidade Classe II/imunologia , Linfócitos T Reguladores/imunologia , Ubiquitinação/imunologia , Animais , Apresentação de Antígeno/imunologia , Células Dendríticas/imunologia , Células Epiteliais/imunologia , Feminino , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Baço/imunologia , Timo/imunologia , Ubiquitina/imunologia , Ubiquitina-Proteína Ligases/imunologiaRESUMO
Somatically acquired mutations in PHF6 (plant homeodomain finger 6) frequently occur in hematopoietic malignancies and often coincide with ectopic expression of TLX3. However, there is no functional evidence to demonstrate whether these mutations contribute to tumorigenesis. Similarly, the role of PHF6 in hematopoiesis is unknown. We report here that Phf6 deletion in mice resulted in a reduced number of hematopoietic stem cells (HSCs), an increased number of hematopoietic progenitor cells, and an increased proportion of cycling stem and progenitor cells. Loss of PHF6 caused increased and sustained hematopoietic reconstitution in serial transplantation experiments. Interferon-stimulated gene expression was upregulated in the absence of PHF6 in hematopoietic stem and progenitor cells. The numbers of hematopoietic progenitor cells and cycling hematopoietic stem and progenitor cells were restored to normal by combined loss of PHF6 and the interferon α and ß receptor subunit 1. Ectopic expression of TLX3 alone caused partially penetrant leukemia. TLX3 expression and loss of PHF6 combined caused fully penetrant early-onset leukemia. Our data suggest that PHF6 is a hematopoietic tumor suppressor and is important for fine-tuning hematopoietic stem and progenitor cell homeostasis.
Assuntos
Células-Tronco Hematopoéticas/citologia , Proteínas de Homeodomínio/metabolismo , Leucemia/etiologia , Proteínas Repressoras/fisiologia , Animais , Carcinogênese , Regulação da Expressão Gênica , Humanos , Camundongos , Camundongos Knockout , Receptores de Interferon , Proteínas Repressoras/genética , Proteínas Supressoras de TumorRESUMO
Although the proapoptotic BH3-only protein, Bim, is required for deletion of autoreactive thymocytes, Bim-deficient mice do not succumb to extensive organ-specific autoimmune disease. To determine whether other BH3-only proteins safeguard tolerance in the absence of Bim, we screened mice lacking Bim as well as other BH3-only proteins. Most strains showed no additional defects; however, mice deficient for both Puma and Bim spontaneously developed autoimmunity in multiple organs, and their T cells could transfer organ-specific autoimmunity. Puma- and Bim-double-deficient mice had a striking accumulation of mature, single-positive thymocytes, suggesting an additional defect in thymic deletion was the basis for disease. Transgenic mouse models of thymocyte deletion by peripheral neoantigens confirmed that the loss of Bim and Puma allowed increased numbers of autoreactive thymocytes to escape deletion. Our data show that Puma cooperates with Bim to impose a thymic-deletion checkpoint to peripheral self-antigens and cement the notion that defects in apoptosis alone are sufficient to cause autoimmune disease.
Assuntos
Proteínas Reguladoras de Apoptose/imunologia , Autoantígenos/imunologia , Autoimunidade/imunologia , Proteínas de Membrana/imunologia , Proteínas Proto-Oncogênicas/imunologia , Timócitos/imunologia , Proteínas Supressoras de Tumor/imunologia , Animais , Apoptose/genética , Apoptose/imunologia , Proteínas Reguladoras de Apoptose/genética , Autoimunidade/genética , Proteína 11 Semelhante a Bcl-2 , Diferenciação Celular/genética , Diferenciação Celular/imunologia , Feminino , Citometria de Fluxo , Masculino , Proteínas de Membrana/genética , Camundongos , Camundongos da Linhagem 129 , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Transgênicos , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas c-bcl-2/genética , Proteínas Proto-Oncogênicas c-bcl-2/imunologia , Tolerância a Antígenos Próprios/genética , Tolerância a Antígenos Próprios/imunologia , Linfócitos T/imunologia , Linfócitos T/metabolismo , Timócitos/metabolismo , Proteína Supressora de Tumor p53/genética , Proteína Supressora de Tumor p53/imunologia , Proteínas Supressoras de Tumor/genéticaRESUMO
The differentiation of hematopoietic precursors into the many functionally distinct T-cell types produced by the thymus is a complex process. It proceeds through a series of stages orchestrated by a variety of thymic microenvironments that shape the T-cell developmental processes. Numerous cytokine and cell surface receptors direct thymocyte differentiation but the primary determinant of cell fate is the engagement of the T-cell antigen receptor (TCR). The strength of the TCR signal and the maturation stage of the thymocyte receiving it can direct the various differentiation programs or, alternatively, end the process by inducing cell death. The regulation of thymocyte death is critical for the efficiency of thymic T-cell differentiation and the preservation of immune tolerance. A detailed knowledge of mechanisms that eliminate thymocytes from the T-cell repertoire is essential to understand the "logic" of T-cell selection in the thymus. This review focuses on the central role of the BCL-2 family of proteins in the apoptotic checkpoints that punctuate thymocyte differentiation and the consequences of defects in these processes.
Assuntos
Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Linfócitos T/fisiologia , Timócitos/fisiologia , Timo/imunologia , Animais , Morte Celular , Diferenciação Celular , Microambiente Celular , Tolerância Central , Hematopoese , Humanos , Receptores de Antígenos de Linfócitos T/metabolismoRESUMO
T-cell differentiation is governed by interactions with thymic epithelial cells (TECs) and defects in this process undermine immune function and tolerance. To uncover new strategies to restore thymic function and adaptive immunity in immunodeficiency, we sought to determine the molecular mechanisms that control life and death decisions in TECs. Guided by gene expression profiling, we created mouse models that specifically deleted prosurvival genes in TECs. We found that although BCL-2 and BCL-XL were dispensable for TEC homeostasis, MCL-1 deficiency impacted on TECs as early as embryonic day 15.5, resulting in early thymic atrophy and T-cell lymphopenia, with near complete loss of thymic tissue by 2 months of age. MCL-1 was not necessary for TEC differentiation but was continually required for the survival of mature cortical and medullary TECs and the maintenance of thymic architecture. A screen of TEC trophic factors in organ cultures showed that epidermal growth factor upregulated MCL-1 via MAPK/ERK kinase activity, providing a molecular mechanism for the support of TEC survival. This signaling axis governing TEC survival and thymic function represents a new target for strategies for thymic protection and regeneration.
Assuntos
Sobrevivência Celular/genética , Células Epiteliais/metabolismo , Proteína de Sequência 1 de Leucemia de Células Mieloides/genética , Proteína de Sequência 1 de Leucemia de Células Mieloides/metabolismo , Timo/fisiologia , Animais , Diferenciação Celular/genética , Diferenciação Celular/imunologia , Sobrevivência Celular/efeitos dos fármacos , Fator de Crescimento Epidérmico/farmacologia , Células Epiteliais/efeitos dos fármacos , Feminino , Expressão Gênica , Perfilação da Expressão Gênica , Regulação da Expressão Gênica , Técnicas de Silenciamento de Genes , Homeostase/genética , Imunofenotipagem , Linfopenia/genética , Masculino , Camundongos , Camundongos Knockout , Proteínas Proto-Oncogênicas c-bcl-2/genética , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Subpopulações de Linfócitos T/citologia , Subpopulações de Linfócitos T/imunologia , Subpopulações de Linfócitos T/metabolismo , Timócitos/citologia , Timócitos/imunologia , Timócitos/metabolismo , Timo/patologia , Proteína bcl-X/genética , Proteína bcl-X/metabolismoRESUMO
Natural killer cells constitute potent innate lymphoid cells that play a major role in both tumor immunosurveillance and viral clearance via their effector functions. A four-stage model of NK cell functional maturation has been established according to the expression of CD11b and CD27, separating mature NK (mNK) cells into distinct populations that exhibit specific phenotypic and functional properties. To identify genetic factors involved in the regulation of NK cell functional maturation, we performed a linkage analysis on F2 (B6.Rag1-/- × NOD.Rag1-/- intercross) mice. We identified six loci on chromosomes 2, 4, 7, 10, 11, and 18 that were linked to one or more mNK cell subsets. Subsequently, we performed an in silico analysis exploiting mNK cell subset microarray data, highlighting various genes and microRNAs as potential regulators of the functional maturation of NK cells. Together, the combination of our unbiased genetic linkage study and the in silico analysis positions genes known to affect NK cell biology along the specific stages of NK cell functional maturation. Moreover, this approach allowed us to uncover a novel candidate gene in the regulation of NK cell maturation, namely Trp53 Using mice deficient for Trp53, we confirm that this tumor suppressor regulates NK cell functional maturation. Additional candidate genes revealed in this study may eventually serve as targets for the modulation of NK cell functional maturation to potentiate both tumor immunosurveillance and viral clearance.
Assuntos
Regulação da Expressão Gênica , Ligação Genética , Células Matadoras Naturais/fisiologia , Proteína Supressora de Tumor p53/genética , Proteína Supressora de Tumor p53/metabolismo , Animais , Antígeno CD11b/imunologia , Diferenciação Celular , Processos de Crescimento Celular , Células Cultivadas , Simulação por Computador , Proteínas de Homeodomínio/genética , Proteínas de Homeodomínio/imunologia , Células Matadoras Naturais/imunologia , Camundongos , Camundongos Endogâmicos NOD , MicroRNAs/genética , MicroRNAs/imunologia , Membro 7 da Superfamília de Receptores de Fatores de Necrose Tumoral/imunologiaRESUMO
γδ T cells respond to molecules upregulated following infection or cellular stress using both TCR and non-TCR molecules. The importance of innate signals versus TCR ligation varies greatly. Both innate-like IL-17-producing γδ T (γδT-17) and IFN-γ-producing γδ T (γδT-IFNγ) subsets tune the sensitivity of their TCR following thymic development, allowing robust responses to inflammatory cytokines in the periphery. The remaining conventional γδ T cells retain high TCR responsiveness. We determined homeostatic mechanisms that govern these various subsets in the peripheral lymphoid tissues. We found that, although innate-like γδT-17 and γδT-IFNγ cells share elements of thymic development, they diverge when it comes to homeostasis. Both exhibit acute sensitivity to cytokines compared with conventional γδ T cells, but they do not monopolize the same cytokine. γδT-17 cells rely exclusively on IL-7 for turnover and survival, aligning them with NKT17 cells; IL-7 ligation triggers proliferation, as well as promotes survival, upregulating Bcl-2 and Bcl-xL. γδT-IFNγ cells instead depend heavily on IL-15. They display traits analogous to memory CD8(+) T cells and upregulate Bcl-xL and Mcl-1 upon cytokine stimulation. The conventional γδ T cells display low sensitivity to cytokine-alone stimulation and favor IL-7 for their turnover, characteristics reminiscent of naive αß T cells, suggesting that they may also require tonic TCR signaling for population maintenance. These survival constraints suggest that γδ T cell subsets do not directly compete with each other for cytokines, but instead fall into resource niches with other functionally similar lymphocytes.
Assuntos
Homeostase/imunologia , Imunidade Inata/imunologia , Subpopulações de Linfócitos T/imunologia , Linfócitos T/imunologia , Transferência Adotiva , Animais , Citocinas/imunologia , Citometria de Fluxo , Interferon gama/biossíntese , Interferon gama/imunologia , Interleucina-17/biossíntese , Interleucina-17/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Receptores de Antígenos de Linfócitos T gama-deltaRESUMO
Targeting survival mechanisms of immune cells may provide an avenue for immune intervention to dampen unwanted responses (e.g. autoimmunity, immunopathology and transplant rejection) or enhance beneficial ones (e.g. immune deficiency, microbial defence and cancer immunotherapy). The selective survival mechanisms of the various immune cell types also avails the possibility of specific tailoring of such interventions. Here, we review the role of the BCL-2 anti-apoptotic family members (BCL-2, BCL-XL, BCL-W, MCL-1 and A1) on cell death/survival of the major immune cell types, for example, T, NK, B, dendritic cell (DC) lineages. There is both selectivity and redundancy among this family. Selectivity comes partly from the expression levels in each of the cell types. For example, plasmacytoid DC express abundant BCL-2 and are susceptible to BCL-2 antagonism or deficiency, whereas conventional DC express abundant A1 and are susceptible to A1 deficiency. There is, however, also functional redundancy; for example, overexpression of MCL-1 can override BCL-2 antagonism in plasmacytoid DC. Moreover, susceptibility to another anti-apoptotic family member can be unmasked, when one or other member is removed. These dual principles of selectivity and redundancy should guide the use of antagonists for manipulating immune cells.
Assuntos
Apoptose , Células Dendríticas/metabolismo , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Proteína bcl-X/metabolismo , Animais , Sobrevivência Celular , Humanos , Terapia de Alvo Molecular , Proteína de Sequência 1 de Leucemia de Células Mieloides , Proteínas Proto-Oncogênicas c-bcl-2/genética , Transcriptoma , Proteína bcl-X/genéticaRESUMO
Dysregulation of the "intrinsic" apoptotic pathway is associated with the development of cancer and autoimmune disease. Bak and Bax are two proapoptotic members of the Bcl-2 protein family with overlapping, essential roles in the intrinsic apoptotic pathway. Their activity is critical for the control of cell survival during lymphocyte development and homeostasis, best demonstrated by defects in thymic T-cell differentiation and peripheral lymphoid homeostasis caused by their combined loss. Because most bak(-/-)bax(-/-) mice die perinatally, the roles of Bax and Bak in immunological tolerance and prevention of autoimmune disease remain unclear. We show that mice reconstituted with a Bak/Bax doubly deficient hematopoietic compartment develop a fatal systemic lupus erythematosus-like autoimmune disease characterized by hypergammaglobulinemia, autoantibodies, lymphadenopathy, glomerulonephritis, and vasculitis. Importantly, these mice also develop a multiorgan autoimmune disease with autoantibodies against most solid glandular structures and evidence of glandular atrophy and necrotizing vasculitis. Interestingly, similar albeit less severe pathology was observed in mice containing a hematopoietic compartment deficient for only Bak, a phenotype reminiscent of the disease seen in patients with point mutations in BAK. These studies demonstrate a critical role for Bak and an ancillary role for Bax in safeguarding immunological tolerance and prevention of autoimmune disease. This suggests that direct activators of the intrinsic apoptotic pathway, such as BH3 mimetics, may be useful for treatment of diverse autoimmune diseases.