RESUMO
Natural Killer (NK) cells play a key role in cancer immunosurveillance. However, NK cells from cancer patients display an altered phenotype and impaired effector functions. In addition, evidence of a regulatory role for NK cells is emerging in diverse models of viral infection, transplantation, and autoimmunity. Here, we analyzed clear cell renal cell carcinoma (ccRCC) datasets from The Cancer Genome Atlas (TCGA) and observed that a higher expression of NK cell signature genes is associated with reduced survival. Analysis of fresh tumor samples from ccRCC patients unraveled the presence of a high frequency of tumor-infiltrating PD-L1+ NK cells, suggesting that these NK cells might exhibit immunoregulatory functions. In vitro, PD-L1 expression was induced on NK cells from healthy donors (HD) upon direct tumor cell recognition through NKG2D and was further up-regulated by monocyte-derived IL-18. Moreover, in vitro generated PD-L1hi NK cells displayed an activated phenotype and enhanced effector functions compared to PD-L1- NK cells, but simultaneously, they directly inhibited CD8+ T cell proliferation in a PD-L1-dependent manner. Our results suggest that tumors might drive the development of PD-L1-expressing NK cells that acquire immunoregulatory functions in humans. Hence, rational manipulation of these regulatory cells emerges as a possibility that may lead to improved anti-tumor immunity in cancer patients.
Assuntos
Antígeno B7-H1/biossíntese , Linfócitos T CD8-Positivos/citologia , Carcinoma de Células Renais/imunologia , Neoplasias Renais/imunologia , Células Matadoras Naturais/metabolismo , Carcinoma de Células Renais/genética , Carcinoma de Células Renais/metabolismo , Carcinoma de Células Renais/mortalidade , Linhagem Celular Tumoral , Proliferação de Células , Células Cultivadas , Conjuntos de Dados como Assunto , Intervalo Livre de Doença , Expressão Gênica , Humanos , Interferon gama/farmacologia , Interleucina-18/farmacologia , Células K562 , Estimativa de Kaplan-Meier , Neoplasias Renais/genética , Neoplasias Renais/metabolismo , Neoplasias Renais/mortalidade , Monitorização Imunológica , Monócitos/metabolismo , Proteínas Recombinantes/farmacologia , Regulação para CimaRESUMO
After recognition, NK cells can kill susceptible target cells through perforin-dependent mechanisms or by inducing death receptor-mediated apoptosis, and they can also secrete cytokines that are pivotal for immunomodulation. Despite the critical role as effector cells against tumors and virus-infected cells, NK cells have been implicated in the regulation of T cell-mediated responses in different models of autoimmunity, transplantation, and viral infections. Here, we review the mechanisms described for NK cell-mediated inhibition of adaptive immune responses, with spotlight on the emerging evidence of their regulatory role that shapes antitumor immune responses.
Assuntos
Imunidade Adaptativa/imunologia , Citotoxicidade Imunológica/imunologia , Infecções/imunologia , Células Matadoras Naturais/imunologia , Neoplasias/imunologia , Animais , HumanosRESUMO
Natural killer (NK) cells can kill virus-infected cells and tumor cells without prior sensitization and secrete numerous cytokines and chemokines that modulate the activity of different cells of the immune system. The recognition of target cells is mediated by germ line-encoded receptors, and the activity of NK cells can be further regulated by soluble factors such as cytokines and Toll-like receptor ligands. Thus, NK cells display an exciting potential as a powerful immunotherapeutic tool against malignant diseases, and different strategies are being tested aiming to overcome tumor-induced NK cell suppression and restore NK-cell mediated antitumor activity. This section describes different flow cytometry-based protocols to study NK cell effector functions, which can be used to evaluate the immunomodulatory ability of different therapeutic compounds.
Assuntos
Imunomodulação/imunologia , Células Matadoras Naturais/imunologia , Degranulação Celular , Membrana Celular/metabolismo , Separação Celular , Humanos , Células Matadoras Naturais/fisiologia , Fenótipo , Coloração e RotulagemRESUMO
In recent times, our understanding of the role of the immune system in different physiopathological situations has increased markedly. A new set of cells, generically known as innate lymphoid cells (ILC), has been discovered in the lymphoid compartment. Five ILC subsets can be recognized according to phenotypic and functional similarities with different subpopulations of T lymphocytes. Unlike T and B lymphocytes, ILC do not express antigen receptors nor undergo selection and clonal expansion upon activation. Instead, they respond rapidly to cytokines and danger signals in infected or inflamed tissues, producing cytokines that direct the immune response toward a type suitable for controlling the initial insult. In addition, ILC establish a crosstalk with other cells of the microenvironment that contributes to the maintenance and restoration of tissue homeostasis. Although many evidences on ILC were obtained from animal models, solid data confirm their existence in humans and their role in various inflammatory disorders. In this article, we address new knowledge on ILC, particularly on their role in the homeostasis of the immune system and in various inflammatory pathologies, in order to present new actors regulating immunity and immunopathology and affecting human health.
En tiempos recientes, nuestra comprensión del rol del sistema inmune en diferentes situaciones fisiopatológicas ha aumentado notablemente. En el compartimiento linfoide se ha descubierto un conjunto de células denominadas células linfoides innatas o innate lymphoid cells (ILC). Las ILC incluyen cinco grupos, clasificados según su similitud fenotípica y funcional con diferentes subpoblaciones de linfocitos T. A diferencia de los linfocitos T y B, las ILC no expresan receptores de antígeno ni sufren selección y expansión clonal cuando se activan. En cambio, responden rápidamente frente a citoquinas y señales de peligro en tejidos infectados o inflamados produciendo citoquinas que dirigen la respuesta inmune hacia un tipo adecuado para controlar la noxa original. Además, las ILC establecen un diálogo cruzado con otras células del microambiente que contribuye al mantenimiento y la restauración de la homeostasis tisular. Si bien muchas evidencias acerca de las ILC fueron obtenidas en modelos animales, existen datos sólidos que confirman su existencia en seres humanos y su papel en diversos trastornos inflamatorios. En este artículo, abordamos los nuevos conocimientos acerca de las ILC, y su rol en la homeostasis del sistema inmune y en diversas patologías inflamatorias, con el fin de presentar nuevos actores que regulan la inmunidad y la inmunopatología, lo que repercute en la salud humana.
Assuntos
Homeostase/imunologia , Imunidade Inata/imunologia , Inflamação/imunologia , Enteropatias/imunologia , Pneumopatias/imunologia , Linfócitos/imunologia , Dermatopatias/imunologia , Homeostase/fisiologia , Humanos , Inflamação/fisiopatologia , Enteropatias/fisiopatologia , Pneumopatias/fisiopatologia , Dermatopatias/fisiopatologiaRESUMO
Interleukin (IL)-23 is a member of the IL-12 family of cytokines that, as the other members of this family, is secreted by monocytes, macrophages, and dendritic cells (DC) upon recognition of bacterial, viral, and fungal components. IL-23 is critical during immunity against acute infections, and it is also involved in the development of autoimmune diseases. Although immunoregulatory effects of IL-23 on mouse natural killer (NK) cells have been described, the effect of IL-23 on human NK cells remains ill-defined. In this study, we observed that monocytes stimulated with LPS secreted IL-23 and that blockade of this cytokine during monocyte and NK cell coculture led to a diminished production of IFN-γ by NK cells. Accordingly, rIL-23-induced NK cell activation and stimulated IFN-γ production by CD56bright NK cells. This effect involved MEK1/MEK2, JNK, PI3K, mammalian target of rapamycin, and NF-κB, but not STAT-1, STAT-3, nor p38 MAPK pathways. Moreover, while NK cell-mediated cytotoxicity remained unaltered, antibody-dependent cellular cytotoxicity (ADCC) was enhanced after IL-23 stimulation. In addition, IL-23 displayed a synergistic effect with IL-18 for IFN-γ production by both CD56bright and CD56dim NK cells, and this effect was due to a priming effect of IL-23 for IL-18 responsiveness. Furthermore, NK cells pre-stimulated with IL-18 promoted an increase in CD86 expression and IL-12 secretion by DC treated with LPS, and IL-23 potentiated these effects. Moreover, IL-23-driven enhancement of NK cell "helper" function was dependent on NK cell-derived IFN-γ. Therefore, our results suggest that IL-23 may trigger NK cell-mediated "helper" effects on adaptive immunity, shaping T cell responses during different pathological situations through the regulation of DC maturation.
RESUMO
IL-27, a member of the IL-12 family of cytokines, is produced by APCs, and displays pro- and anti-inflammatory effects. How IL-27 affects human NK cells still remains unknown. In this study, we observed that mature DCs secreted IL-27 and that blockade of IL-27R (CD130) reduced the amount of IFN-γ produced by NK cells during their coculture, showing the importance of IL-27 during DC-NK-cell crosstalk. Accordingly, human rIL-27 stimulated IFN-γ secretion by NK cells in a STAT1-dependent manner, induced upregulation of CD25 and CD69 on NK cells, and displayed a synergistic effect with IL-18. Preincubation experiments demonstrated that IL-27 primed NK cells for IL-18-induced IFN-γ secretion, which was associated with an IL-27-driven upregulation of T-bet expression. Also, IL-27 triggered NKp46-dependent NK-cell-mediated cytotoxicity against Raji, T-47D, and HCT116 cells, and IL-18 enhanced this cytotoxic response. Such NK-cell-mediated cytotoxicity involved upregulation of perforin, granule exocytosis, and TRAIL-mediated cytotoxicity but not Fas-FasL interaction. Moreover, IL-27 also potentiated Ab-dependent cell-mediated cytotoxicity against mAb-coated target cells. Taken together, IL-27 stimulates NK-cell effector functions, which might be relevant in different physiological and pathological situations.
Assuntos
Células Dendríticas/imunologia , Interleucina-18/farmacologia , Interleucinas/farmacologia , Células Matadoras Naturais/imunologia , Anticorpos Monoclonais/farmacologia , Antígenos CD/genética , Antígenos CD/imunologia , Antígenos de Diferenciação de Linfócitos T/genética , Antígenos de Diferenciação de Linfócitos T/imunologia , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/imunologia , Técnicas de Cocultura , Receptor gp130 de Citocina/genética , Receptor gp130 de Citocina/imunologia , Citotoxicidade Imunológica , Células Dendríticas/citologia , Células Dendríticas/efeitos dos fármacos , Regulação da Expressão Gênica , Células HCT116 , Humanos , Interleucina-18/imunologia , Subunidade alfa de Receptor de Interleucina-2/genética , Subunidade alfa de Receptor de Interleucina-2/imunologia , Interleucinas/imunologia , Células Matadoras Naturais/citologia , Células Matadoras Naturais/efeitos dos fármacos , Lectinas Tipo C/genética , Lectinas Tipo C/imunologia , Cultura Primária de Células , Proteínas Recombinantes/farmacologia , Transdução de SinaisRESUMO
HDACi are being used as a novel, therapeutic approach for leukemias and other hematological malignancies. However, their effect on immune cells remains ill-defined, as HDACi may impair immune surveillance. In this work, we demonstrate that TSA, VPA, and NaB inhibited IFN-γ production by CD56(dim) and CD56(bright) NK cells and NK cell-mediated cytotoxicity against K562 target cells. HDACi promoted minor NK cell apoptosis but inhibited nuclear mobilization of NF-κB p50, which was accompanied by a robust down-regulation of NKG2D and NKp46 on resting NK cells and of NKG2D, NKp44, NKp46, and CD25 on cytokine-activated NK cells. Decreased CD25 expression promoted a weakened IFN-γ secretion upon restimulation of NK cells with IL-2, whereas reduced expression of NKG2D and NKp46 was accompanied by an impaired NKG2D- and NKp46-dependent cytotoxicity. Moreover, NK cells from normal mice treated in vivo with TSA displayed a diminished expression of NK1.1, NKG2D, and NKp46 and secreted reduced amounts of IFN-γ upon ex vivo stimulation with cytokines. Thus, our preclinical results indicate that HDACi exert deleterious effects on NK cell function, which may weaken immune surveillance and facilitate relapse of the malignant disease in HDACi-treated patients.
Assuntos
Antineoplásicos/farmacologia , Butiratos/farmacologia , Inibidores de Histona Desacetilases/farmacologia , Ácidos Hidroxâmicos/farmacologia , Vigilância Imunológica/efeitos dos fármacos , Células Matadoras Naturais/efeitos dos fármacos , Ativação Linfocitária/efeitos dos fármacos , Animais , Antineoplásicos/efeitos adversos , Apoptose/efeitos dos fármacos , Linfócitos T CD4-Positivos/efeitos dos fármacos , Linfócitos T CD4-Positivos/imunologia , Linhagem Celular Tumoral , Células Cultivadas/efeitos dos fármacos , Células Cultivadas/imunologia , Células Cultivadas/metabolismo , Grânulos Citoplasmáticos/efeitos dos fármacos , Grânulos Citoplasmáticos/metabolismo , Citotoxicidade Imunológica , Inibidores de Histona Desacetilases/efeitos adversos , Humanos , Interferon gama/metabolismo , Interleucinas/farmacologia , Células Matadoras Naturais/imunologia , Células Matadoras Naturais/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Subfamília K de Receptores Semelhantes a Lectina de Células NK/biossíntese , Subfamília K de Receptores Semelhantes a Lectina de Células NK/genética , Receptor 1 Desencadeador da Citotoxicidade Natural/biossíntese , Receptor 1 Desencadeador da Citotoxicidade Natural/genética , VorinostatRESUMO
The MHC class I chain-related protein A (MICA) is an inducible molecule almost not expressed by normal cells but strongly up-regulated in tumor cells. MICA-expressing cells are recognized by natural killer (NK) cells, CD8+ abTCR and gdTCR T lymphocytes through the NKG2D receptor. Engagement of NKG2D by MICA triggers IFN-g secretion and cytotoxicity against malignant cells. Although most solid tumors express MICA and this molecule is a target during immune surveillance against tumors, it has been observed that high grade tumors from different histotypes express low amounts of cell surface MICA due to a metalloprotease-induced shedding. Also, melanomas develop after a complex process of neotransformation of normal melanocytes. However, the expression of MICA in premalignant stages (primary human quiescent melanocytic nevi) remains unknown. Here, we assessed expression of MICA by flow cytometry using cell suspensions from 15 primary nevi isolated from 11 patients. When collected material was abundant, cell lysates were prepared and MICA expression was also analyzed by Western blot. We observed that MICA was undetectable in the 15 primary nevi (intradermic, junction, mixed, lentigo and congenital samples) as well as in normal skin, benign lesions (seborrheic keratosis), premalignant lesions (actinic keratosis) and benign basocellular cancer. Conversely, a primary recently diagnosed melanoma showed intense cell surface MICA. We conclude that the onset of MICA expression is a tightly regulated process that occurs after melanocytes trespass the stage of malignant transformation. Thus, analysis of MICA expression in tissue sections of skin samples may constitute a useful marker to differentiate between benign and malignant nevi.
Assuntos
Antígenos de Histocompatibilidade Classe I/metabolismo , Nevo/metabolismo , Lesões Pré-Cancerosas/metabolismo , Neoplasias Cutâneas/metabolismo , Citometria de Fluxo , Antígenos de Histocompatibilidade Classe I/imunologia , Humanos , Nevo/imunologia , Nevo/patologia , Lesões Pré-Cancerosas/imunologia , Lesões Pré-Cancerosas/patologia , Neoplasias Cutâneas/imunologia , Neoplasias Cutâneas/patologiaRESUMO
The inflammatory response is a self-limiting process which involves the sequential activation of signaling pathways leading to the production of both pro- and anti-inflammatory mediators. Galectin-1 (Gal-1), an endogenous lectin found in peripheral lymphoid organs and inflammatory sites, elicits a broad spectrum of biological functions predominantly by acting as a potent anti-inflammatory factor and as a suppressive agent for T-cell responses. However, the molecular pathways underlying Gal-1 expression and function remain poorly understood. Here we identified a regulatory loop linking Gal-1 expression and function to NF-κB activation. NF-κB-activating stimuli increased Gal-1 expression on T cells, an effect which could be selectively prevented by inhibitors of NF-κB signaling. Accordingly, transient transfection of the p65 subunit of NF-κB was sufficient to induce high Gal-1 expression. Using in silico studies and chromatin immunoprecipitation analysis we have identified a functional NF-κB binding site within the first intron of the LGALS1 gene. In addition, our results show that exogenous Gal-1 can attenuate NF-κB activation, as shown by inhibition of IκB-α degradation induced by pro-inflammatory stimuli, higher cytoplasmic retention of p65, lower NF-κB DNA binding activity and impaired transcriptional activation of target genes. The present study suggest a novel regulatory loop by which NF-κB induces expression of Gal-1, which in turn may lead to negative control of NF-κB signaling.
Assuntos
Galectina 1/biossíntese , Regulação da Expressão Gênica/imunologia , NF-kappa B/metabolismo , Transdução de Sinais/imunologia , Sítios de Ligação , Western Blotting , Células Cultivadas , Imunoprecipitação da Cromatina , Ensaio de Desvio de Mobilidade Eletroforética , Retroalimentação Fisiológica/fisiologia , Galectina 1/genética , Galectina 1/imunologia , Expressão Gênica , Humanos , Microscopia Confocal , NF-kappa B/imunologia , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Linfócitos T/imunologia , Linfócitos T/metabolismo , TransfecçãoRESUMO
Natural killer (NK) cells trigger cytotoxicity and interferon (IFN)-gamma secretion on engagement of the natural-killer group (NKG)2D receptor or members of the natural cytotoxicity receptor (NCR) family, such as NKp46, by ligands expressed on tumour cells. However, it remains unknown whether T cells can regulate NK cell-mediated anti-tumour responses. Here, we investigated the early events occurring during T cell-tumour cell interactions, and their impact on NK cell functions. We observed that on co-culture with some melanomas, activated CD4(+) T cells promoted degranulation, and NKG2D- and NKp46-dependent IFN-gamma secretion by NK cells, probably owing to the capture of NKG2D and NKp46 ligands from the tumour-cell surface (trogocytosis). This effect was observed in CD4(+), CD8(+) and resting T cells, which showed substantial amounts of cell surface major histocompatibility complex class I chain-related protein A on co-culture with tumour cells. Our findings identify a new, so far, unrecognized mechanism by which effector T cells support NK cell function through the capture of specific tumour ligands with profound implications at the crossroad of innate and adaptive immunity.