RESUMEN
Histone deacetylase (HDAC) inhibitors are small molecules inducing cell-cycle arrest, differentiation, and apoptosis, currently undergoing clinical trials as anticancer drugs. In addition, emerging evidence suggests HDAC inhibitors may have anti-inflammatory and immunomodulatory properties as well, although the molecular mechanisms remain poorly defined. Given the central role of dendritic cells (DC) in the induction and maintenance of the inflammatory and immune response, we investigated the effects of HDAC inhibitors on the maturation and activation of human monocyte-derived DC in the presence of LPS and IFN-gamma. Our results show that the production of T(H)1- and T(H)17-inducing cytokines, namely IL-12 and IL-23, was inhibited by trichostatin A (72% and 52%, respectively) and suberoylanilide hydroxamic acid (86% and 83%). Strikingly, HDAC inhibitors were effective if added simultaneously as well as after the proinflammatory challenge, and their effect was not associated to a reduction of expression or function of LPS/IFN-gamma receptors. These findings were confirmed in two different murine models. In addition, HDAC inhibitors selectively blocked the production of T(H)1-attracting chemokines CXCL9, CXCL10, and CXCL11. The reduction of T(H)1- and T(H)17-inducing cytokines as well as T(H)1-attracting chemokines may represent relevant mechanisms through which HDAC inhibitors at nonproapoptotic doses exert their immunomodulatory properties.
Asunto(s)
Inhibidores Enzimáticos/farmacología , Inhibidores de Histona Desacetilasas , Interleucina-12/metabolismo , Interleucina-23/metabolismo , Linfocitos T Colaboradores-Inductores/inmunología , Animales , Células Cultivadas , Quimiocinas/genética , Quimiocinas/metabolismo , Citocinas/antagonistas & inhibidores , Citocinas/metabolismo , Células Dendríticas/efectos de los fármacos , Células Dendríticas/metabolismo , Ensayo de Inmunoadsorción Enzimática , Femenino , Histona Desacetilasas/metabolismo , Humanos , Ácidos Hidroxámicos/farmacología , Técnicas In Vitro , Interferón gamma/metabolismo , Interleucina-12/antagonistas & inhibidores , Interleucina-23/antagonistas & inhibidores , Lipopolisacáridos/farmacología , Ratones , Ratones Endogámicos C57BL , Monocitos/citología , Monocitos/efectos de los fármacos , Monocitos/metabolismo , ARN Mensajero/genética , ARN Mensajero/metabolismo , Receptores de Interferón/metabolismo , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Vorinostat , Receptor de Interferón gammaRESUMEN
Traditionally described as a major anti-coagulant system, the protein C (PC) pathway, consisting of thrombomodulin, the endothelial cell protein C receptor and activated PC (APC), is gaining increasing attention as an important regulator of microvascular inflammation. Although they possess several anti-inflammatory and cytoprotective functions, the expression and function of the components of the PC pathway is downregulated during inflammation. Recent evidence suggests that the PC pathway is defective in patients with inflammatory bowel disease (IBD) and that restoring its function has anti-inflammatory effects on cultured intestinal microvascular endothelial cells and in animal models of colitis. Here, we propose that the PC pathway has an important role in governing intestinal microvascular inflammation and might provide a novel therapeutic target in the management of IBD.
Asunto(s)
Enfermedades Inflamatorias del Intestino/metabolismo , Proteína C/metabolismo , Transducción de Señal , Animales , Coagulación Sanguínea , Endotelio Vascular/inmunología , Endotelio Vascular/metabolismo , Humanos , Inflamación , Enfermedades Inflamatorias del Intestino/inmunología , Mucosa Intestinal/inmunología , Mucosa Intestinal/metabolismoRESUMEN
In the human body, mucosal surfaces of the intestinal tract are the largest and one of the most complex parts of the immune system. These surfaces are covered by a layer of epithelial cells which allows efficient absorption of nutrients but also serves to separate the intestine from an environment loaded with potential harmful agents. Discrimination between beneficial commensal bacteria, harmless antigens and pathogenic microorganisms is a central issue in the role that gut immune cells play in maintaining the balance between immune response and tolerance. However, the basis of this discrimination in the mucosal immune system, where this occurs and how it can affect both local and systemic responses is not yet well understood. Nevertheless, antigen uptake and presentation seems to be a crucial factor in this issue. In this review, we will discuss the key role of immune intestinal cells in the development of mucosal immunity, tolerance and disease.
Asunto(s)
Colitis/inmunología , Tolerancia Inmunológica , Inmunidad Mucosa , Mucosa Intestinal/inmunología , Neoplasias Intestinales/inmunología , Intestinos/inmunología , Animales , Bacterias/inmunología , Bacterias/patogenicidad , Colitis/complicaciones , Colitis/microbiología , Colitis/patología , Células Dendríticas/inmunología , Células Epiteliales/inmunología , Humanos , Interleucina-10/metabolismo , Mucosa Intestinal/microbiología , Mucosa Intestinal/patología , Neoplasias Intestinales/microbiología , Neoplasias Intestinales/patología , Intestinos/microbiología , Intestinos/patología , Ganglios Linfáticos/inmunología , Macrófagos/inmunología , Ganglios Linfáticos Agregados/inmunología , Linfocitos T Reguladores/inmunología , Factor de Crecimiento Transformador beta/metabolismo , Escape del TumorRESUMEN
Although animals can be immunized against the growth of some tumor implants, most of the attempts to use immunotherapy to cause the regression of animal and human tumors once they have become established have been disappointing even when strongly immunogenic tumors were used as target. In this paper, we demonstrate that the failure to achieve an efficient immunological treatment against an established strongly immunogenic murine fibrosarcoma was paralleled with the emergence of a state of immunological unresponsiveness (immunological eclipse) against tumor antigens observed when the tumor surpassed the critical size of 500 mm(3). In turn, the onset of the immunological eclipse was coincidental with the onset of a systemic inflammatory condition characterized by a high number of circulating and splenic polymorphonucleated neutrophils (PMN) displaying activation and Gr1(+)Mac1(+) phenotype and an increasing serum concentration of the pro-inflammatory cytokines TNF-alpha, IL-1beta and IL-6 cytokines and C-reactive protein (CRP) and serum A amyloid (SAA) phase acute proteins. Treatment of tumor-bearing mice with a single low dose (0.75 mg/kg) of the synthetic corticoid dexamethasone (DX) significantly reduced all the systemic inflammatory parameters and simultaneously reversed the immunological eclipse, as evidenced by the restoration of specific T-cell-dependent concomitant immunity, ability of spleen cells to transfer anti-tumor activity and recovery of T-cell signal transduction molecules. Two other anti-inflammatory treatments by using indomethacin or dimeric TNF-alpha receptor, also partially reversed the immunological eclipse although the effect was not as striking as that observed with DX. The reversion of the immunological eclipse was not enough on its own to inhibit the primary growing tumor. However, when we used the two-step strategy of inoculating DX to reverse the eclipse and then dendritic cells loaded with tumor antigens (DC) as an immunization booster, a significant inhibition of the growth of both established tumors and remnant tumor cells after excision of large established tumors was observed, despite the fact that the vaccination alone (DC) had no effect or even enhanced tumor growth in certain circumstances. The two-step strategy of tumor immunotherapy that we present is based on the rationale that it is necessary to eliminate or ameliorate the immunological eclipse as a precondition to allow an otherwise ineffective anti-tumor immunological therapy to have a chance to be successful.
Asunto(s)
Antiinflamatorios/uso terapéutico , Células Dendríticas/trasplante , Tolerancia Inmunológica/efectos de los fármacos , Inmunoterapia/métodos , Inflamación/tratamiento farmacológico , Neoplasias Experimentales/terapia , Animales , Western Blotting , Vacunas contra el Cáncer/uso terapéutico , Células Dendríticas/inmunología , Dexametasona/uso terapéutico , Femenino , Citometría de Flujo , Masculino , Ratones , Ratones Endogámicos BALB C , Neoplasias Experimentales/inmunologíaRESUMEN
The interaction between immune complexes (IC) and the receptors for the Fc portion of IgG (FcgammaRs) triggers regulatory and effector functions in the immune system. In this study, we investigated the effects of IC on differentiation, maturation, and functions of human monocyte-derived dendritic cells (DC). When IC were added on day 0, DC generated on day 6 (IC-DC) showed lower levels of CD1a and increased expression of CD14, MHC class II, and the macrophage marker CD68, as compared with normally differentiated DC. The use of specific blocking FcgammaR mAbs indicated that the effect of IC was exerted mainly through their interaction with FcgammaRI and to a lesser extend with FcgammaRII. Immature IC-DC also expressed higher levels of CD83, CD86, and CD40 and the expression of these maturation markers was not further regulated by LPS. The apparent lack of maturation following TLR stimulation was associated with a decreased production of IL-12, normal secretion of IL-10 and CCL22, and increased production of CXCL8 and CCL2. IC-DC displayed low endocytic activity and a reduced ability to induce allogeneic T cell proliferation both at basal and LPS-stimulated conditions. Altogether, these data reveal that IC strongly affect DC differentiation and maturation. Skewing of DC function from Ag presentation to a proinflammatory phenotype by IC resembles the state of activation observed in DC obtained from patients with chronic inflammatory autoimmune disorders, such as systemic lupus erythematosus disease and arthritis. Therefore, the altered maturation of DC induced by IC may be involved in the pathogenesis of autoimmune diseases.
Asunto(s)
Complejo Antígeno-Anticuerpo/fisiología , Diferenciación Celular/inmunología , Linaje de la Célula/inmunología , Células Dendríticas/citología , Células Dendríticas/inmunología , Inhibidores de Crecimiento/fisiología , Monocitos/citología , Monocitos/inmunología , Animales , Complejo Antígeno-Anticuerpo/sangre , Enfermedades Autoinmunes/inmunología , Enfermedades Autoinmunes/metabolismo , Enfermedades Autoinmunes/patología , Células Cultivadas , Células Dendríticas/metabolismo , Células Dendríticas/patología , Relación Dosis-Respuesta Inmunológica , Inhibidores de Crecimiento/sangre , Humanos , Inmunoglobulina G/metabolismo , Lupus Eritematoso Sistémico/inmunología , Lupus Eritematoso Sistémico/metabolismo , Lupus Eritematoso Sistémico/patología , Activación de Linfocitos/inmunología , Prueba de Cultivo Mixto de Linfocitos , Monocitos/metabolismo , Monocitos/patología , Conejos , Receptores de IgG/antagonistas & inhibidores , Receptores de IgG/biosíntesis , Receptores de IgG/fisiología , Linfocitos T/inmunología , Factores de TiempoRESUMEN
Although animals can be prophylactically immunized against the growth of tumor implants, most of the attempts to use immunotherapy to cause the regression of animal and human tumors once they become established have been unsuccessful. To understand the nature of this refractoriness we have studied a methylcholanthrene-induced and strongly immunogenic murine fibrosarcoma. In our model, the onset of this refractoriness was associated with the beginning of an immunosuppressive state known as "immunological eclipse" characterized by a loss of the antitumor immune response when tumor grows beyond a critical size. This immunological eclipse was accompanied by the emergence of a systemic inflammatory condition. Treatment of tumor-bearing mice with a single dose of a synthetic corticosteroid, dexamethasone (DX), reduced significantly all parameters of systemic inflammation and simultaneously reversed the immunological eclipse. The reversion of the eclipse upon DX treatment was not curative itself, but allowed an immunological therapy based in dendritic cells pulsed with tumor antigens, which was itself absolutely ineffective, to exert a significant inhibitory effect against an established growing tumor. The two-step schedule using an anti-inflammatory treatment to reverse the immunological eclipse plus a dendritic cell-based vaccination strategy aimed to stimulate the antitumor immune response, could serve eventually as a model of immunotherapy against animal and human tumors.
Asunto(s)
Vacunas contra el Cáncer/uso terapéutico , Células Dendríticas/inmunología , Fibrosarcoma/tratamiento farmacológico , Tolerancia Inmunológica/inmunología , Sarcoma Experimental/tratamiento farmacológico , Animales , Antiinflamatorios/inmunología , Antiinflamatorios/uso terapéutico , Vacunas contra el Cáncer/inmunología , Carcinógenos , Dexametasona/inmunología , Dexametasona/uso terapéutico , Supervivencia sin Enfermedad , Fibrosarcoma/inducido químicamente , Fibrosarcoma/inmunología , Tolerancia Inmunológica/efectos de los fármacos , Inflamación/tratamiento farmacológico , Metilcolantreno , Ratones , Ratones Endogámicos BALB C , Sarcoma Experimental/inducido químicamente , Sarcoma Experimental/inmunologíaRESUMEN
Aunque existen vacunas para prevenir la aparición de tumores en animales de experimentación, la mayoría de los intentos por aplicar aquellas vacunas con fines terapéuticos contra tumores establecidos no han sido exitosos. Para comprender la naturaleza de esta refractariedad, estudiamos un tumor de ratón fuertemente inmunogénico inducido por el carcinógeno químico metilcolantreno. En nuestro modelo, el inicio de esta refractariedad coincidió con el comienzo de un estado de inmunosupresión conocido como "eclipse inmunológico" caracterizado por una pérdida o bloqueo de la respuesta inmune antitumoral después que el tumor ha superado cierto tamaño crítico. Este eclipse inmunológico fue acompañado por un proceso de inflamación sistémica en el organismo. El tratamiento de los ratones portadores de tumor con una única dosis del corticoide sintético dexametasona (DX) redujo los parámetros de inflamación sistémica e indujo la reversión del eclipse. Esta reversión no fue por sí misma curativa pero permitió que un tratamiento inmunológico basado en células dendríticas estimuladas con antígenos tumorales, que por sí solo era absolutamente ineficaz, pudiera ejercer un significativo efecto inhibidor sobre un tumor en crecimiento. El esquema de dos pasos que comprende, primero, un tratamiento antiinflamatorio para revertir el eclipse y segundo, una estrategia de vacunación basada en células dendríticas destinada a estimular la respuesta inmune antitumoral, podría servir, eventualmente, como un modelo de inmunoterapia contra tumores en animales y seres humanos.
Although animals can be prophylactically immunized against the growth of tumor implants, most of the attempts to use immunotherapy to cause the regression of animal and human tumors once they become established have been unsuccessful. To understand the nature of this refractoriness we have studied a methylcholanthrene-induced and strongly immunogenic murine fibrosarcoma. In our model, the onset of this refractoriness was associated with the beginning of an immunosuppressive state known as "immunological eclipse" characterized by a loss of the antitumor immune response when tumor grows beyond a critical size. This immunological eclipse was accompanied by the emergence of a systemic inflammatory condition. Treatment of tumor-bearing mice with a single dose of a synthetic corticosteroid, dexamethasone (DX), reduced significantly all parameters of systemic inflammation and simultaneously reversed the immunological eclipse. The reversion of the eclipse upon DX treatment was not curative itself, but allowed an immunological therapy based in dendritic cells pulsed with tumor antigens, which was itself absolutely ineffective, to exert a significant inhibitory effect against an established growing tumor. The two-step schedule using an anti-inflammatory treatment to reverse the immunological eclipse plus a dendritic cell-based vaccination strategy aimed to stimulate the anti-tumor immune response, could serve eventually as a model of immunotherapy against animal and human tumors.
Asunto(s)
Humanos , Animales , Ratones , Antiinflamatorios/uso terapéutico , Vacunas contra el Cáncer/uso terapéutico , Células Dendríticas/inmunología , Dexametasona/uso terapéutico , Fibrosarcoma/tratamiento farmacológico , Terapia de Inmunosupresión/métodos , Sarcoma Experimental/tratamiento farmacológico , Antiinflamatorios/inmunología , Vacunas contra el Cáncer/inmunología , Supervivencia sin Enfermedad , Dexametasona/inmunología , Fibrosarcoma/inmunología , Inflamación/tratamiento farmacológico , Ratones Endogámicos BALB C , Metilcolantreno/efectos adversos , Sarcoma Experimental/inmunologíaRESUMEN
1,25-Dihydroxyvitamin D(3) (1,25(OH)(2)D(3)) is an immunomodulatory agent inducing dendritic cells (DCs) to become tolerogenic. To further understand its mechanisms of action, we have examined the effects of 1,25(OH)(2)D(3) on tolerogenic properties of blood myeloid (M-DCs) and plasmacytoid (P-DCs) human DC subsets. Exposure of M-DCs to 1,25(OH)(2)D(3) up-regulated production of CCL22, a chemokine attracting regulatory T cells, whereas production of CCL17, the other CCR4 ligand, was reduced. 1,25(OH)(2)D(3) also decreased IL-12p75 production by M-DCs, as expected, and inhibited CCR7 expression. 1,25(OH)(2)D(3) treatment markedly increased CD4(+) suppressor T cell activity while decreasing the capacity of M-DCs to induce Th1 cell development. Surprisingly, 1,25(OH)(2)D(3) did not exert any discernible effect on tolerogenic properties of P-DCs, and even their high production of IFN-alpha was not modulated. In particular, the intrinsically high capacity of P-DCs to induce CD4(+) suppressor T cells was unaffected by 1,25(OH)(2)D(3). Both DC subsets expressed similar levels of the vitamin D receptor, and its ligation by 1,25(OH)(2)D(3) similarly activated the primary response gene cyp24. Interestingly, 1,25(OH)(2)D(3) inhibited NF-kappaB p65 phosphorylation and nuclear translocation in M-DCs but not P-DCs, suggesting a mechanism for the inability of 1,25(OH)(2)D(3) to modulate tolerogenic properties in P-DCs.
Asunto(s)
Calcitriol/farmacología , Calcitriol/fisiología , Células Dendríticas/efectos de los fármacos , Tolerancia Inmunológica/efectos de los fármacos , Células Mieloides/efectos de los fármacos , Transporte Activo de Núcleo Celular , Antígenos CD4/análisis , Quimiocina CCL17 , Quimiocina CCL22 , Quimiocinas CC/metabolismo , Células Dendríticas/inmunología , Expresión Génica/efectos de los fármacos , Antígenos de Histocompatibilidad Clase II/genética , Humanos , Terapia de Inmunosupresión , Ligandos , Glicoproteínas de Membrana , Células Mieloides/inmunología , FN-kappa B/metabolismo , Fosforilación , Células Plasmáticas/efectos de los fármacos , Células Plasmáticas/inmunología , Receptores CCR4 , Receptores de Calcitriol/agonistas , Receptores de Superficie Celular/genética , Receptores de Quimiocina/metabolismo , Receptores Inmunológicos , Células TH1/efectos de los fármacos , Células TH1/inmunología , Transcripción Genética/efectos de los fármacosRESUMEN
Dendritic cells (DCs) are able to open the tight junctions between adjacent epithelial cells (ECs) and to take up both invasive and noninvasive bacteria directly from the intestinal lumen. In this study, we describe a tight cross talk between ECs and human monocyte-derived DCs (MoDCs) in bacterial handling across epithelial monolayers. We show that the release of proinflammatory mediators by ECs in response to bacteria is dependent on bacterial invasiveness and on the presence of flagella. This correlates with the capacity of EC-derived factors to modulate MoDC function. MoDCs incubated with supernatants of bacteria-treated ECs are "noninflammatory" as they release interleukin-10 (IL-10) but not IL-12 and can drive only T helper (Th)-2 type T cells. Moreover, noninflammatory MoDCs release chemokines aimed at recruiting Th2 and T-regulatory cells. In contrast, when MoDCs are incubated with ECs and bacteria in a transwell coculture system, and can contact directly the bacteria across stimulated EC monolayers, they are more inflammatory as they release IL-12 and IL-10 and induce both Th1 and Th2 responses. These results suggest that ECs are not simply a barrier to bacteria entering via the oral route, but they actively influence the activating properties of DCs.
Asunto(s)
Diferenciación Celular , Células Dendríticas/citología , Células Dendríticas/inmunología , Células Epiteliales/inmunología , Células Epiteliales/microbiología , Bacterias Grampositivas/fisiología , Monocitos/citología , Animales , Células Cultivadas , Quimiocina CCL20 , Quimiocinas CC/metabolismo , Células Dendríticas/metabolismo , Células Epiteliales/citología , Células Epiteliales/metabolismo , Flagelos/fisiología , Bacterias Grampositivas/citología , Bacterias Grampositivas/patogenicidad , Humanos , Interleucina-10/metabolismo , Interleucina-12/metabolismo , Proteínas Inflamatorias de Macrófagos/metabolismo , Ratones , Monocitos/inmunología , Monocitos/metabolismo , Células TH1/inmunología , Células Th2/inmunologíaRESUMEN
Activation of NADPH oxidase represents an essential mechanism of defense against pathogens. Dendritic cells (DC) are phagocytic cells specialized in Ag presentation rather than in bacteria killing. Human monocyte-derived DC were found to express the NADPH oxidase components and to release superoxide anions in response to phorbol esters and phagocytic agonists. The NADPH oxidase components p47phox and gp91phox were down-regulated during monocyte differentiation to DC, and maturation of DC with pathogen-derived molecules, known to activate TLRs, increased p47phox and gp91phox expression and enhanced superoxide anions release. Similar results were obtained with plasmacytoid DC following maturation with influenza virus. In contrast, activation of DC by immune stimuli (CD40 ligand) did not regulate NADPH oxidase components or respiratory burst. NADPH oxidase-derived oxygen radicals did not play any role in DC differentiation, maturation, cytokine production, and induction of T cell proliferation, as based on the normal function of DC generated from chronic granulomatous disease patients and the use of an oxygen radical scavenger. However, NADPH oxidase activation was required for DC killing of intracellular Escherichia coli. It is likely that the selective regulation of oxygen radicals production by pathogen-activated DC may function to limit pathogen dissemination during DC trafficking to secondary lymphoid tissues.
Asunto(s)
Células Dendríticas/enzimología , Células Dendríticas/inmunología , Glicoproteínas de Membrana/fisiología , NADPH Oxidasas/metabolismo , Receptores de Superficie Celular/fisiología , Adolescente , Adulto , Diferenciación Celular/inmunología , Línea Celular Tumoral , Células Cultivadas , Niño , Preescolar , Células Dendríticas/metabolismo , Células Dendríticas/patología , Escherichia coli/crecimiento & desarrollo , Escherichia coli/inmunología , Femenino , Enfermedad Granulomatosa Crónica/inmunología , Enfermedad Granulomatosa Crónica/microbiología , Enfermedad Granulomatosa Crónica/patología , Humanos , Líquido Intracelular/inmunología , Líquido Intracelular/microbiología , Ligandos , Lipopolisacáridos/farmacología , Glicoproteínas de Membrana/metabolismo , NADPH Oxidasas/fisiología , Fagocitosis/inmunología , Receptores de Superficie Celular/metabolismo , Estallido Respiratorio/inmunología , Receptores Toll-Like , Regulación hacia Arriba/inmunologíaRESUMEN
Regulation of inflammation is a crucial event since its alteration, such as in sepsis and chronic autoimmune (i.e. rheumatoid arthritis, lupus erythematosus) or infectious diseases (i.e. tuberculosis, leprosy), determines severe tissue damage. Although there is a general consensus that regulation of inflammation results from a balance between proinflammatory and antiinflammatory pathways, we arrived at the conclusion that well known chemoattractants/proinflammatory molecules such as bacterial formyl peptides or immune complexes (IC), could induce, paradoxically, strong antiinflammatory effects. Thus, we demonstrated that N-formyl-methionyl-leucyl-phenylalanine (FMLP) exerted a drastic antiinflammatory effect, inhibiting the secretion of tumor necrosis alpha (TNF-alpha) induced by lipopolysaccharides, a potent TNF-alpha inducer. We also determined that in human neutrophils FMLP and IC induced the downregulation of receptors for the Fc portion of IgG (FcgammaRII and FcgammaRIIIB). Moreover, FMLP inhibited interferon gamma (IFN-gamma)-induced FcgammaRI expression and IC downregulate class II molecules of the major histocompatibility complex on monocytes. Part of these effects were mediated by the release of aspartic-, serin-, or metalloproteases. All these results favor the postulation of a new concept on the regulation of inflammation carried out through an alternative and non conventional pathway, in which a chemoattractant/proinflammatory agent could, under certain circumstances, act as an antiinflammatory molecule.
Asunto(s)
Complejo Antígeno-Anticuerpo/inmunología , Inflamación/inmunología , N-Formilmetionina Leucil-Fenilalanina/farmacología , Neutrófilos/inmunología , Receptores de IgG/inmunología , Factor de Necrosis Tumoral alfa/efectos de los fármacos , Regulación de la Expresión Génica/inmunología , Regulación de la Expresión Génica/fisiología , Humanos , Inflamación/fisiopatología , Interferón gamma/metabolismo , Monocitos/inmunología , Monocitos/metabolismo , Neutrófilos/metabolismo , Receptores de IgG/metabolismo , Factor de Necrosis Tumoral alfa/fisiologíaRESUMEN
The promiscuous D6 receptor binds several inflammatory CC chemokines and has been recently proposed to act as a chemokine-scavenging decoy receptor. The present study was designed to better characterize the spectrum of CC chemokines scavenged by D6, focusing in particular on CCR4 ligands and analyzing the influence of NH(2)-terminal processing on recognition by this promiscuous receptor. Using D6 transfectants, it was found that D6 efficiently bound and scavenged most inflammatory CC chemokines (CCR1 through CCR5 agonists). Homeostatic CC chemokines (CCR6 and CCR7 agonists) were not recognized by D6. The CCR4 agonists CC chemokine ligand 17 (CCL17) and CCL22 bound to D6 with high affinity. CCL17 and CCL22 have no agonistic activity for D6 (chemotaxis and calcium fluxes), but were rapidly scavenged, resulting in reduced chemotactic activity on CCR4 transfectants. CD26 mediates NH(2) terminus processing of CCL22, leading to the production of CCL22 (3-69) and CCL22 (5-69) that do not interact with CCR4. These NH(2)-terminal truncated forms of CCL22 were not recognized by D6. The results presented in this study show that D6 recognizes and scavenges a wide spectrum of inflammatory CC chemokines, including the CCR4 agonists CCL22 and CCL17. However, this promiscuous receptor is not engaged by CD26-processed, inactive, CCL22 variants. By recognizing intact CCL22, but not its truncated variants, D6 expressed on lymphatic endothelial cells may regulate the traffic of CCR4-expressing cells, such as dendritic cells.
Asunto(s)
Quimiocinas CC/metabolismo , Macrófagos/inmunología , Macrófagos/metabolismo , Receptores de Quimiocina/metabolismo , Animales , Unión Competitiva/inmunología , Células CHO , Línea Celular , Línea Celular Tumoral , Quimiocina CCL17 , Quimiocina CCL22 , Quimiocinas CC/fisiología , Células Clonales , Cricetinae , Células Dendríticas/inmunología , Células Dendríticas/metabolismo , Dipeptidil Peptidasa 4/fisiología , Endotelio Linfático/inmunología , Endotelio Linfático/metabolismo , Humanos , Inflamación/inmunología , Inflamación/metabolismo , Ratones , Isoformas de Proteínas/metabolismo , Procesamiento Proteico-Postraduccional , Receptores CCR10 , Receptores CCR4 , Receptores de Quimiocina/agonistas , Receptores de Quimiocina/biosíntesis , Receptores de Quimiocina/fisiología , Eliminación de Secuencia , Transfección , Receptor de Quimiocina D6RESUMEN
The use of leukemia cells as antigen-presenting cells (APCs) in immunotherapy is critically dependent on their capacity to initiate and sustain an antitumor-specific immune response. Previous studies suggested that pediatric B-cell precursor acute lymphoblastic leukemia (BCP-ALL) cells could be manipulated in vitro through the CD40-CD40L pathway to increase their immunostimulatory capacity. We extended the APC characterization of CD40L-activated BCP-ALL for their potential use in immunotherapy in a series of 19 patients. Engaging CD40 induced the up-regulation of CCR7 in 7 of 11 patients and then the migration to CCL19 in 2 of 5 patients. As accessory cells, CD40L-activated BCP-ALL induced a strong proliferation response of naive T lymphocytes. Leukemia cells, however, were unable to sustain proliferation over time, and T cells eventually became anergic. After CD40-activation, BCP-ALL cells released substantial amounts of interleukin-10 (IL-10) but were unable to produce bioactive IL-12 or to polarize TH1 effectors. Interestingly, adding exogenous IL-12 induced the generation of interferon-gamma (IFN-gamma)-secreting TH1 effectors and reverted the anergic profile in a secondary response. Therefore, engaging CD40 on BCP-ALL cells is insufficient for the acquisition of full functional properties of immunostimulatory APCs. These results suggest caution against the potential use of CD40L-activated BCP-ALL cells as agents for immunotherapy unless additional stimuli, such as IL-12, are provided.
Asunto(s)
Células Presentadoras de Antígenos/inmunología , Linfocitos B/inmunología , Antígenos CD40/inmunología , Anergia Clonal/inmunología , Interleucina-10/inmunología , Interleucina-12/deficiencia , Leucemia-Linfoma Linfoblástico de Células Precursoras/inmunología , Linfocitos T/inmunología , Antígenos CD/inmunología , Células de la Médula Ósea/inmunología , Niño , Humanos , Interleucina-12/genética , Interleucina-12/inmunología , Activación de Linfocitos , Receptores CCR7 , Receptores de Quimiocina/inmunologíaRESUMEN
Dendritic cells (DCs) comprise a family of cells specializing in antigen capture and presentation to T cells. We have recently shown that DC play an active role in bacterial uptake across mucosal surfaces. Indeed, DC are able to open tight junctions and to sample antigens directly across epithelia, both in vitro and in vivo. Because DC express tight junction proteins, the integrity of the epithelial barrier is preserved. In this study we have analyzed the possible involvement of epithelial cells in controlling DC function. We developed an in vitro model in our laboratory consisting of a three-player system of dendritic cells, epithelial cell monolayers, and bacteria. The crosstalk between epithelial cells and dendritic cells was analyzed, and epithelial cells were tested for their capacity to release cytokines and chemokines that induce the migration and activation of DC. We show that the capacity of epithelial cells to produce cytokines and activate DC is dependent on the invasiveness of the bacteria tested. In particular, invasive bacteria stimulate epithelial cells to release proinflammatory cytokines and to induce the maturation state of DC. By contrast, noninvasive bacteria are unable to stimulate epithelial cells, but can activate DC directly when DC translocate to the apical side. In conclusion, epithelial cells are not simply a barrier to bacteria entering via the oral route, but actively influence the activating properties of bystander DC.
Asunto(s)
Infecciones Bacterianas/inmunología , Células Dendríticas/inmunología , Mucosa Intestinal/inmunología , Animales , Bacillus subtilis/inmunología , Quimiocinas/inmunología , Técnicas de Cocultivo , Citocinas/inmunología , Células Dendríticas/citología , Humanos , Mucosa Intestinal/citología , Lactobacillus plantarum/inmunología , Ratones , Salmonella typhimurium/genética , Salmonella typhimurium/inmunología , Uniones Estrechas/inmunologíaRESUMEN
Hipótesis: una vía alternativa de regulación de procesos inflamatorios. La regulación de mecanismos inflamatorios es un evento crucial debido a que una alteración de los mismos, como sucede por ejemplo, en la sepsis, en enfermedades autoinmunes crónicas (artritis reumatoidea, lupus eritematoso) o en enfermedades infecciosas (tuberculosis, lepra), genera daños tisulares severos. Aunque hay un consenso general de que la regulación de procesos inflamatorios resulta de un balance entre vías proinflamatorias y antiinflamatorias, nosotros arribamos a la conclusión de que moléculas quimioatractantes / proinflamatorias como, por ejemplo, péptidos formilados bacterianos o complejos inmunes (CI), pueden también inducir, paradójicamente, potentes efectos ntiinflamatorios. Así, demostramos que el péptido formilado prototipo N-formilmetionil- leucil-fenilalanina (FMLP), ejerce un drástico efecto antiinflamatorio, inhibiendo la secreción de factor de necrosis tumoral alfa (TNF-α) inducido por lipopolisacáridos, un potente inductor de la secreción de TNF-α. También determinamos que el FMLP y los CI inducen la disminución de la expresión de receptores para el fragmento Fc de IgG (FcγRII and FcγRIIIB) en neutrófilos humanos. Más aún, el FMLP inhibe la inducción de la expresión de los FcγRI por interferón gamma (IFN-γ) y los CI disminuyen la expresión de moléculas de clase II del complejo mayor de histocompatibilidad en monocitos humanos. Parte de esos efectos fueron mediados por la liberación de aspártico-, serino-, o metaloproteasas. Todos estos resultados nos permiten especular sobre un nuevo concepto en el cual la regulación de los procesos inflamatorios también puede llevarse a cabo por una vía alternativa, no convencional, en la cual un agente quimioatractante / proinflamatorio, bajo determinadas circunstancias, puede actuar como una molécula antiinflamatoria.
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Humanos , Complejo Antígeno-Anticuerpo , Regulación de la Expresión Génica/fisiología , Inflamación/inmunología , N-Formilmetionina Leucil-Fenilalanina/farmacología , Neutrófilos/inmunología , Receptores de IgG/inmunología , Factor de Necrosis Tumoral alfa , Regulación de la Expresión Génica/inmunología , Interferón gamma , Inflamación/fisiopatología , Monocitos/inmunología , Monocitos/metabolismo , Neutrófilos/metabolismo , Receptores de IgG/metabolismo , Factor de Necrosis Tumoral alfaRESUMEN
Dendritic cells (DCs) and macrophages are professional antigen-presenting cells (APCs) that play key roles in both innate and adaptive immunity. ChemR23 is an orphan G protein-coupled receptor related to chemokine receptors, which is expressed specifically in these cell types. Here we present the characterization of chemerin, a novel chemoattractant protein, which acts through ChemR23 and is abundant in a diverse set of human inflammatory fluids. Chemerin is secreted as a precursor of low biological activity, which upon proteolytic cleavage of its COOH-terminal domain, is converted into a potent and highly specific agonist of ChemR23, the chemerin receptor. Activation of chemerin receptor results in intracellular calcium release, inhibition of cAMP accumulation, and phosphorylation of p42-p44 MAP kinases, through the Gi class of heterotrimeric G proteins. Chemerin is structurally and evolutionary related to the cathelicidin precursors (antibacterial peptides), cystatins (cysteine protease inhibitors), and kininogens. Chemerin was shown to promote calcium mobilization and chemotaxis of immature DCs and macrophages in a ChemR23-dependent manner. Therefore, chemerin appears as a potent chemoattractant protein of a novel class, which requires proteolytic activation and is specific for APCs.
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Células Presentadoras de Antígenos/fisiología , Quimiocinas/fisiología , Receptores de Quimiocina/metabolismo , Secuencia de Aminoácidos , Calcio/metabolismo , Movimiento Celular , Quimiocinas/química , Quimiocinas/genética , Quimiocinas/aislamiento & purificación , Células Dendríticas/fisiología , Humanos , Péptidos y Proteínas de Señalización Intercelular , Datos de Secuencia MolecularRESUMEN
Dendritic cells (DC) orchestrate the trafficking of lymphocytes by secreting chemokines with different specificity and function. Chemokines are produced at higher levels by mature DC. This study shows that CCL18 is one of the most abundant chemokines produced by immature DC. In contrast to all other chemokines investigated to date, CCL18 was selectively down-regulated during the maturation process induced by LPS, TNF, CD40 ligand, Staphylococcus aureus Cowan I, Candida albicans, and influenza virus. IL-10 and vitamin D(3), two known inhibitors of DC differentiation and function, strongly promoted CCL18 secretion, whereas IFN-gamma, a costimulator of DC function, inhibited its production. IL-10 also induced CCL18 secretion in blood myeloid DC. No CCL18 secretion was observed in blood plasmacytoid DC. The opposite pattern of regulation was observed for CCL20, a prototypic inflammatory chemokine. CCL18 was found to be a chemotactic factor for immature DC. Therefore, CCL18 may act as a chemotactic signal that promotes the colocalization of immature DC with naive T lymphocytes in an IL-10-dominated environment with the consequent generation of T regulatory cells. These characteristics suggest that CCL18 may be part of an inhibitory pathway devoted to limiting the generation of specific immune responses at peripheral sites.
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Quimiocinas CC/biosíntesis , Células Dendríticas/inmunología , Células Dendríticas/metabolismo , Diferenciación Celular/efectos de los fármacos , Diferenciación Celular/inmunología , Células Cultivadas , Quimiocinas CC/antagonistas & inhibidores , Quimiocinas CC/metabolismo , Quimiocinas CC/fisiología , Quimiotaxis de Leucocito/inmunología , Colecalciferol/farmacología , Células Dendríticas/citología , Dexametasona/farmacología , Dinoprostona/farmacología , Inhibidores de Crecimiento/farmacología , Humanos , Inmunosupresores/farmacología , Interferón gamma/farmacología , Interleucina-10/farmacología , Células Mieloides/citología , Células Mieloides/inmunología , Células Mieloides/metabolismo , Células Plasmáticas/citología , Células Plasmáticas/inmunología , Células Plasmáticas/metabolismoRESUMEN
To examine the different roles of myeloid dendritic cells (M-DCs) and plasmacytoid dendritic cells (P-DCs) in the induction and regulation of immune response, we have studied chemokine secretion by freshly isolated DC subsets in response to bacterial, viral, and T cell-derived stimuli. M-DCs selectively produced very high levels of the homeostatic chemokines CC chemokine ligand (CCL)17 and CCL22, while P-DCs produced very little if any. In contrast, the proinflammatory chemokine CCL3 was secreted mostly by P-DCs, whereas CCL4 and CXC chemokine ligand 8 were produced by both subsets. The selective production of CCL17 and CCL22 by M-DCs but not P-DCs was confirmed in vivo by immunohistology on human reactive lymph node sections. The high production of CCR4 ligands by M-DCs suggests their capacity to selectively recruit at sites of inflammation T cells with regulatory properties or with a Th2 phenotype, whereas P-DCs, by preferentially secreting CCR1/CCR5 ligands, would mostly recruit effector T cells and, in particular, Th1-type cells.
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Quimiocinas/biosíntesis , Células Dendríticas/inmunología , Células Dendríticas/metabolismo , Células Mieloides/inmunología , Células Mieloides/metabolismo , Linaje de la Célula/inmunología , Células Cultivadas , Quimiocina CCL17 , Quimiocina CCL22 , Quimiocina CCL3 , Quimiocina CCL4 , Quimiocinas/sangre , Quimiocinas CC/biosíntesis , Células Dendríticas/clasificación , Humanos , Proteínas Inflamatorias de Macrófagos/biosíntesisRESUMEN
The existence of dendritic cell (DC) subsets is firmly established, but their trafficking properties are still largely unknown. We have indicated that myeloid dendritic cells (M-DCs) and plasmacytoid dendritic cells (P-DCs) isolated from human blood differ widely in the capacity to migrate to chemotactic stimuli. The pattern of chemokine receptors expressed ex vivo by both subsets is similar, but P-DCs display, compared with M-DCs, higher levels of CC chemokine receptor (CCR)5, CCR7, and CXCR3. Intriguingly, most chemokine receptors of P-DCs, in particular those specific for inflammatory chemokines and classical chemotactic agonists, are not functional in circulating cells. Following maturation induced by cluster designation (CD)40 ligation, the receptors for inflammatory chemokines are downregulated and CCR7 on P-DCs becomes coupled to migration. The drastically impaired capacity of blood P-DCs to migrate in response to inflammatory chemotactic signals contrasts with the response to lymph node-homing chemokines, indicating a propensity to migrate to secondary lymphoid organs rather than to sites of inflammation. The distinct migration behavior of DC subsets is accompanied by a different profile of chemokine production. In contrast to the high production by M-DCs, the homeostatic CC chemokine ligand (CCL)17/ thymus- and activation-regulated chemokine (TARC) is not produced by PDCs in response to any stimulus tested and their production of CCL22/MDC is minimal, if any, compared with M-DCs. Thus, stimulated M-DCs, but not P-DCs, are able to produce high levels of chemokines recruiting T-helper 2 cells (Th2) and T-regulatory cells. Conversely, the proinflammatory chemokine CCL3/macrophage inflammatory protein (MIP)-1alpha is predominantly produced by P-DCs. Therefore, P-DCs appear to produce preferentially proinflammatory chemokines, but to respond selectively to homeostatic ones, whereas the reverse is true for M-DCs, highlighting not only the different migratory properties of these DC subsets, but also their capacity to recruit different cell types at inflammation sites.
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Quimiocinas/biosíntesis , Células Dendríticas/metabolismo , Células Mieloides/metabolismo , Células Plasmáticas/metabolismo , Movimiento Celular/inmunología , Quimiocinas/sangre , Células Dendríticas/citología , Células Dendríticas/inmunología , Humanos , Células Mieloides/inmunología , Células Plasmáticas/citología , Células Plasmáticas/inmunologíaRESUMEN
Juvenile myelo-monocytic leukemia (JMML) is a severe malignant stem cell disorder of childhood. A proportion of cells from JMML mononuclear cells (MNC) spontaneously differentiate in vitro into dendritic cells (DC). We have studied MNC from 14 JMML patients, and characterized their functional activity as antigen presenting cells (APC). Large cells, differentiated after seven days of culture, expressed high levels of MHC II molecules and Mannose Receptor, variable levels of CD80 and CD86, and low levels of CD1a. Similar to immature DC, cells from JMML had high levels of dextran endocytosis, and were able to elicit proliferation of allogeneic T lymphocytes in mixed leukocyte reaction (MLR). CD40L-matured DC from JMML was associated with relevant increase of CD80, CD86 and CD83, increased APC activity, responded in chemotaxis assays to MIP-3beta and secreted increased amounts of macrophage derived chemokine (MDC). Immature DC and CD40L-matured DC from JMML produced very low amounts of IL-12, whereas the production of IL-10 was higher than normal DC. In line with these findings, they showed defective capacity to polarize naive T cells to differentiate into Th1 effectors. These results indicate that MNC from JMML are committed to spontaneously differentiate into DC with morphological and phenotypical characteristics similar to normal DC. The cytokine profile produced by these APC is likely to suppress and not to elicit a protective immune response.