RESUMEN
The pathogenesis of lung fibrosis involves hyperactivation of innate and adaptive immune pathways that release inflammatory cytokines and growth factors such as tumor growth factor (TGF)ß1 and induce aberrant extracellular matrix protein production. During the genesis of pulmonary fibrosis, resident alveolar macrophages are replaced by a population of newly arrived monocyte-derived interstitial macrophages that subsequently transition into alveolar macrophages (Mo-AMs). These transitioning cells initiate fibrosis by releasing profibrotic cytokines and remodeling the matrix. Here, we describe a strategy for leveraging the up-regulation of the mannose receptor CD206 in interstitial macrophages and Mo-AM to treat lung fibrosis. We engineered mannosylated albumin nanoparticles, which were found to be internalized by fibrogenic CD206+ monocyte derived macrophages (Mo-Macs). Mannosylated albumin nanoparticles incorporating TGFß1 small-interfering RNA (siRNA) targeted the profibrotic subpopulation of CD206+ macrophages and prevented lung fibrosis. The findings point to the potential utility of mannosylated albumin nanoparticles in delivering TGFß-siRNA into CD206+ profibrotic macrophages as an antilung fibrosis strategy.
Asunto(s)
Linfotoxina-alfa , Macrófagos Alveolares , Nanopartículas , Fibrosis Pulmonar , ARN Interferente Pequeño , Animales , Bleomicina/farmacología , Modelos Animales de Enfermedad , Linfotoxina-alfa/genética , Macrófagos Alveolares/inmunología , Receptor de Manosa , Ratones , Ratones Endogámicos C57BL , Nanopartículas/administración & dosificación , Fibrosis Pulmonar/inducido químicamente , Fibrosis Pulmonar/inmunología , Fibrosis Pulmonar/terapia , ARN Interferente Pequeño/administración & dosificación , ARN Interferente Pequeño/genéticaRESUMEN
The complex involvement of neutrophils in inflammatory diseases makes them intriguing but challenging targets for therapeutic intervention. Here, we tested the hypothesis that varying endocytosis capacities would delineate functionally distinct neutrophil subpopulations that could be specifically targeted for therapeutic purposes. By using uniformly sized (â¼120 nm in diameter) albumin nanoparticles (ANP) to characterize mouse neutrophils in vivo, we found two subsets of neutrophils, one that readily endocytosed ANP (ANPhigh neutrophils) and another that failed to endocytose ANP (ANPlow population). These ANPhigh and ANPlow subsets existed side by side simultaneously in bone marrow, peripheral blood, spleen, and lungs, both under basal conditions and after inflammatory challenge. Human peripheral blood neutrophils showed a similar duality. ANPhigh and ANPlow neutrophils had distinct cell surface marker expression and transcriptomic profiles, both in naive mice and in mice after endotoxemic challenge. ANPhigh and ANPlow neutrophils were functionally distinct in their capacities to kill bacteria and to produce inflammatory mediators. ANPhigh neutrophils produced inordinate amounts of reactive oxygen species and inflammatory chemokines and cytokines. Targeting this subset with ANP loaded with the drug piceatannol, a spleen tyrosine kinase (Syk) inhibitor, mitigated the effects of polymicrobial sepsis by reducing tissue inflammation while fully preserving neutrophilic host-defense function.
Asunto(s)
Nanopartículas , Neutrófilos , Albúminas/metabolismo , Animales , Endocitosis , Inflamación/tratamiento farmacológico , Inflamación/metabolismo , Ratones , Neutrófilos/metabolismoRESUMEN
Myocarditis, often due to an aberrant immune response to infection, is a major cause of dilated cardiomyopathy. Microbial pattern recognition receptors, such as TLRs, orchestrate the cytokine and chemokine responses that augment or limit the severity of myocarditis. Using the mouse model of experimental autoimmune myocarditis (EAM), in which disease is induced by immunization with a heart-specific self peptide and the agonist to multiple TLRs, complete Freund's adjuvant, we found that increased serum concentrations of the chemokine CXCL1/KC correlated directly with decreased severity of myocarditis. To directly test whether CXCL1/KC caused the amelioration of myocarditis, we treated mice, after challenge with heart-specific self peptide, with exogenous recombinant CXCL1/KC. We found that the administration of recombinant mouse CXCL1/KC completely abrogated heart inflammatory infiltration and cardiomyocyte damage. Moreover, we show that TLR4 signaling is required to increase serum protein concentrations of CXCL1/KC in EAM, and we demonstrate that the administration of the TLR4 agonist LPS significantly decreased severity and prevalence of EAM and reduced the number of heart-specific self peptide reactive effector T cells. These findings reveal a novel function of CXCL1/KC in the context of organ-specific autoimmune disease that may prove useful for the treatment of inflammatory conditions that underlie human heart disease.
Asunto(s)
Enfermedades Autoinmunes/tratamiento farmacológico , Quimiocina CXCL1/administración & dosificación , Miocarditis/tratamiento farmacológico , Animales , Enfermedades Autoinmunes/genética , Enfermedades Autoinmunes/inmunología , Linfocitos B/inmunología , Linfocitos B/metabolismo , Modelos Animales de Enfermedad , Femenino , Ligandos , Ratones , Ratones Noqueados , Modelos Biológicos , Miocarditis/genética , Miocarditis/inmunología , Miocarditis/patología , Cadenas Pesadas de Miosina/química , Cadenas Pesadas de Miosina/metabolismo , Óxido Nítrico Sintasa de Tipo II/metabolismo , Proteínas Recombinantes , Transducción de Señal , Linfocitos T/inmunología , Linfocitos T/metabolismo , Receptor Toll-Like 4/metabolismoRESUMEN
Here we found that the transcription repressor DREAM bound to the promoter of the gene encoding A20 to repress expression of this deubiquitinase that suppresses inflammatory NF-κB signaling. DREAM-deficient mice displayed persistent and unchecked A20 expression in response to endotoxin. DREAM functioned by transcriptionally repressing A20 through binding to downstream regulatory elements (DREs). In contrast, binding of the transcription factor USF1 to the DRE-associated E-box domain in the gene encoding A20 activated its expression in response to inflammatory stimuli. Our studies define the critical opposing functions of DREAM and USF1 in inhibiting and inducing A20 expression, respectively, and thereby the strength of NF-κB signaling. Targeting of DREAM to induce USF1-mediated A20 expression is therefore a potential anti-inflammatory strategy for the treatment of diseases associated with unconstrained NF-κB activity, such as acute lung injury.
Asunto(s)
Proteínas de Unión al ADN/biosíntesis , Inflamación/metabolismo , Péptidos y Proteínas de Señalización Intracelular/biosíntesis , Proteínas de Interacción con los Canales Kv/metabolismo , Proteínas Represoras/metabolismo , Ubiquitina-Proteína Ligasas/biosíntesis , Factores Estimuladores hacia 5'/metabolismo , Lesión Pulmonar Aguda/genética , Lesión Pulmonar Aguda/metabolismo , Animales , Inmunoprecipitación de Cromatina , Cisteína Endopeptidasas , Proteínas de Unión al ADN/genética , Modelos Animales de Enfermedad , Regulación de la Expresión Génica/inmunología , Immunoblotting , Inflamación/genética , Péptidos y Proteínas de Señalización Intracelular/genética , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , FN-kappa B/genética , FN-kappa B/metabolismo , Reacción en Cadena en Tiempo Real de la Polimerasa , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Proteína 3 Inducida por el Factor de Necrosis Tumoral alfa , Ubiquitina-Proteína Ligasas/genéticaRESUMEN
The complement anaphylatoxin C5a has a pathogenetic role in endotoxin-induced lung inflammatory injury by regulating phagocytic cell migration and activation. Endotoxin and C5a activate the enzyme sphingosine kinase (Sphk) 1 to generate the signaling lipid sphingosine-1-phosphate (S1P), a critical regulator of phagocyte function. We assessed the function of Sphk1 and S1P in experimental lung inflammatory injury and determined their roles in anaphylatoxin receptor signaling and on the expression of the two C5a receptors, C5aR (CD88) and C5L2, on phagocytes. We report that Sphk1 gene deficient (Sphk1(-/-)) mice had augmented lung inflammatory response to endotoxin compared to wild type mice. Sphk1 was required for C5a-mediated reduction in cytokine and chemokine production by macrophages. Moreover, neutrophils from Sphk1(-/-) mice failed to upregulate the anaphylatoxin receptor C5L2 in response to LPS. Exogenous S1P restored C5L2 cell surface expression of Sphk1(-/-) mouse neutrophils to wild type levels but had no effect on cell surface expression of the other anaphylatoxin receptor, CD88. These results provide the first genetic evidence of the crucial role of Sphk1 in regulating the balance between expression of CD88 and C5L2 in phagocytes. S1P-mediated up-regulation of C5L2 is a novel therapeutic target for mitigating endotoxin-induced lung inflammatory injury.
Asunto(s)
Lipopolisacáridos/toxicidad , Lisofosfolípidos/farmacología , Fosfotransferasas (Aceptor de Grupo Alcohol)/fisiología , Neumonía/metabolismo , Receptor de Anafilatoxina C5a/metabolismo , Receptores de Quimiocina/metabolismo , Esfingosina/análogos & derivados , Anafilatoxinas/farmacología , Animales , Médula Ósea/efectos de los fármacos , Médula Ósea/metabolismo , Citocinas/metabolismo , Ensayo de Inmunoadsorción Enzimática , Citometría de Flujo , Macrófagos/citología , Macrófagos/efectos de los fármacos , Macrófagos/metabolismo , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Neutrófilos/citología , Neutrófilos/efectos de los fármacos , Neutrófilos/metabolismo , Fosforilación/efectos de los fármacos , Neumonía/inducido químicamente , Neumonía/patología , Sepsis/inducido químicamente , Sepsis/metabolismo , Sepsis/patología , Transducción de Señal/efectos de los fármacos , Esfingosina/farmacologíaRESUMEN
Human embryonic stem cells differentiated under mesoderm-inducing conditions have important therapeutic properties in sepsis-induced lung injury in mice. Single cell suspensions obtained from day 7 human embryoid bodies (d7EBs) injected i.v. 1 hour after cecal ligation and puncture significantly reduced lung inflammation and edema as well as production of tumor necrosis factor-α and interferon-γ in lungs compared with controls, whereas interleukin-10 production remained elevated. d7EB cell transplantation also reduced mortality to 50% from 90% in the control group. The protection was ascribed to d7EB cell interaction with lung resident CD11b+ cells, and was correlated with the ability of d7EB cells to reduce it also reduced production of proinflammatory cytokines by CD11+ cells, and to endothelial NO synthase-derived NO by d7EB cells, leading to inhibition of inducible macrophage-type NO synthase activation in CD11b+ cells. The protective progenitor cells were positive for the endothelial and hematopoietic lineage marker angiotensin converting enzyme (ACE). Only the ACE+ fraction modulated the proinflammatory profile of CD11b+ cells and reduced mortality in septic mice. In contrast to the nonprotective ACE-cell fraction, the ACE+ cell fraction also produced NO. These findings suggest that an ACE+ subset of human embryonic stem cell-derived progenitor cells has a highly specialized anti-inflammatory function that ameliorates sepsis-induced lung inflammation and reduces mortality.
Asunto(s)
Diferenciación Celular , Células Madre Embrionarias/citología , Células Madre Embrionarias/trasplante , Neumonía/cirugía , Sepsis/complicaciones , Animales , Antígeno CD11b/análisis , Separación Celular , Rastreo Celular , Modelos Animales de Enfermedad , Células Madre Embrionarias/química , Humanos , Masculino , Ratones , Ratones Endogámicos , Óxido Nítrico/antagonistas & inhibidores , Óxido Nítrico/biosíntesis , Peptidil-Dipeptidasa A/metabolismo , Neumonía/etiologíaRESUMEN
The mechanism underlying the protective effect of sphingosine kinase 1 (SphK1) in inflammatory injury is not clear. We demonstrated using SphK1-null mice (SphK1(-/-)) the crucial role of SphK1 in suppressing lipopolysaccharide-induced neutrophil oxidant production and sequestration in lungs and mitigating lung inflammatory injury. This effect of SphK1 was independent of the production of sphingosine 1-phosphate, the product of SphK1 activity. The anti-inflammatory effect of SphK1 in the lipopolysaccharide model was mediated through SphK1 interaction with JNK. SphK1 stabilization of JNK in turn inhibited JNK binding to the JNK-interacting protein 3 (JIP3) and thus abrogated the activation of NADPH oxidase and oxidant generation and resultant NF-kappaB activation. Therefore, SphK1-mediated down-regulation of JNK activity serves to dampen inflammation and tissue injury.
Asunto(s)
Lipopolisacáridos/toxicidad , Pulmón/enzimología , MAP Quinasa Quinasa 4/metabolismo , Neutrófilos/enzimología , Fosfotransferasas (Aceptor de Grupo Alcohol)/metabolismo , Neumonía/enzimología , Proteínas Adaptadoras Transductoras de Señales/genética , Proteínas Adaptadoras Transductoras de Señales/metabolismo , Animales , Regulación hacia Abajo/genética , Regulación hacia Abajo/efectos de la radiación , Activación Enzimática/efectos de los fármacos , Activación Enzimática/genética , Lisofosfolípidos/genética , Lisofosfolípidos/metabolismo , MAP Quinasa Quinasa 4/genética , Ratones , Ratones Noqueados , NADPH Oxidasas/genética , NADPH Oxidasas/metabolismo , Proteínas del Tejido Nervioso/genética , Proteínas del Tejido Nervioso/metabolismo , Oxidantes/metabolismo , Fosfotransferasas (Aceptor de Grupo Alcohol)/genética , Neumonía/inducido químicamente , Neumonía/genética , Esfingosina/análogos & derivados , Esfingosina/genética , Esfingosina/metabolismoRESUMEN
Activation of NF-kappaB is essential for protease-activated receptor-1 (PAR-1)-mediated ICAM-1 expression in endothelial cells. Here we show that PAR-1 activation induces binding of both p65/RelA and NFATc1 to the NF-kappaB binding site localized in intron-1 of the ICAM-1 gene to initiate transcription in endothelial cells. We discovered the presence of two NF-kappaB binding sites in intron-1 (+70, NF-kappaB site 1; +611, NF-kappaB site 2) of the human ICAM-1 gene. Chromatin immunoprecipitation results showed that thrombin induced binding of p65/RelA and of NFATc1 specifically to intronic NF-kappaB site 1 of the ICAM-1 gene. Electrophoretic mobility shift and supershift assays confirmed the binding of p65/RelA and NFATc1 to the intronic NF-kappaB site 1 in thrombin-stimulated cells. Thrombin increased the expression of ICAM-1-promoter-intron 1-reporter (-1,385 to +234) construct approximately 25-fold and mutation of intronic NF-kappaB site 1 markedly reduced thrombin-induced reporter expression. Moreover, inhibition of calcineurin, knockdown of either NFATc1 or p65/RelA with siRNA significantly reduced thrombin-induced ICAM-1 expression and polymorphonuclear leukocyte adhesion to endothelial cells. In contrast, NFATc1 knockdown had no effect on TNF-alpha-induced ICAM-1 expression. Thus these results suggest that p65/RelA and NFATc1 bind to the intronic NF-kappaB site 1 sequence to induce optimal transcription of the ICAM-1 gene in response to thrombin in endothelial cells.
Asunto(s)
Regulación de la Expresión Génica/fisiología , Molécula 1 de Adhesión Intercelular/genética , Intrones , FN-kappa B/fisiología , Factores de Transcripción NFATC/metabolismo , Trombina/fisiología , Secuencia de Bases , Células Cultivadas , Inmunoprecipitación de Cromatina , Cartilla de ADN , Técnicas de Silenciamiento del Gen , Humanos , Factores de Transcripción NFATC/genética , ARN Interferente PequeñoRESUMEN
The E3 ubiquitin ligase Cblb has a crucial role in the prevention of chronic inflammation and autoimmunity. Here we show that Cblb also has an unexpected function in acute lung inflammation. Cblb attenuates the sequestration of inflammatory cells in the lungs after administration of lipopolysaccharide (LPS). In a model of polymicrobial sepsis in which acute lung inflammation depends on the LPS receptor (Toll-like receptor 4, TLR-4), the loss of Cblb expression accentuates acute lung inflammation and reduces survival. Loss of Cblb significantly increases sepsis-induced release of inflammatory cytokines and chemokines. Cblb controls the association between TLR4 and the intracellular adaptor MyD88. Expression of wild-type Cblb, but not expression of a Cblb mutant that lacks E3 ubiquitin ligase function, prevents the activity of a reporter gene for the transcription factor nuclear factor-kappaB (NF-kappaB) in monocytes that have been challenged with LPS. The downregulation of TLR4 expression on the cell surface of neutrophils is impaired in the absence of Cblb. Our data reveal that Cblb regulates the TLR4-mediated acute inflammatory response that is induced by sepsis.
Asunto(s)
Proteínas Adaptadoras Transductoras de Señales/metabolismo , Pulmón/enzimología , Pulmón/patología , Neumonía/enzimología , Neumonía/patología , Proteínas Proto-Oncogénicas c-cbl/metabolismo , Enfermedad Aguda , Proteínas Adaptadoras Transductoras de Señales/deficiencia , Proteínas Adaptadoras Transductoras de Señales/genética , Animales , Citocinas/biosíntesis , Eliminación de Gen , Regulación Enzimológica de la Expresión Génica , Lipopolisacáridos/farmacología , Pulmón/efectos de los fármacos , Lesión Pulmonar , Ratones , Ratones Endogámicos BALB C , Ratones Noqueados , Factor 88 de Diferenciación Mieloide/metabolismo , FN-kappa B/metabolismo , Fenotipo , Neumonía/inducido químicamente , Neumonía/genética , Unión Proteica , Transporte de Proteínas , Proteínas Proto-Oncogénicas c-cbl/deficiencia , Proteínas Proto-Oncogénicas c-cbl/genética , Transducción de Señal , Tasa de Supervivencia , Receptor Toll-Like 4/metabolismoRESUMEN
The E3 ubiquitin ligase Casitas B cell lymphoma-b (Cbl-b) plays a critical role in the development of autoimmunity and sets the threshold for T cell activation. In the absence of Cbl-b, T cells stimulated via the TCR respond similarly to those that have received a CD28-mediated costimulatory signal, suggesting that the absence of Cbl-b substitutes for CD28-mediated costimulation. In this study, we show that loss of Cbl-b restores Ig class switching and germinal center formation in Vav1 mutant mice in response to an in vivo viral challenge. Genetic inactivation of Cbl-b also rescues impaired antiviral IgG production in CD28-mutant mice. Moreover, loss of CD28 results in disorganization of follicular dendritic cell clusters, which is also rescued by the Cbl-b mutation. Intriguingly, despite restored antiviral in vivo immunity and follicular dendritic cell clusters, loss of Cbl-b did not rescue germinal center formation in CD28-deficient mice. Mechanistically, in vivo vesicular stomatitis virus-induced IL-4 and IFN-gamma production and up-regulation of the inducible costimulatory molecule ICOS were dependent on CD28, and could not be rescued by the loss of Cbl-b. These data provide genetic evidence that CD28-dependent in vivo immune responses and Ig class switching can be genetically uncoupled from germinal center formation and ICOS induction by Cbl-b-Vav1-regulated signaling pathways.
Asunto(s)
Proteínas Adaptadoras Transductoras de Señales/fisiología , Enfermedades Autoinmunes/inmunología , Antígenos CD28/fisiología , Proteínas de Ciclo Celular/fisiología , Proteínas Proto-Oncogénicas/fisiología , Ubiquitina-Proteína Ligasas/fisiología , Proteínas Adaptadoras Transductoras de Señales/deficiencia , Proteínas Adaptadoras Transductoras de Señales/genética , Animales , Anticuerpos Antivirales/biosíntesis , Antígenos de Diferenciación de Linfocitos T/biosíntesis , Enfermedades Autoinmunes/genética , Enfermedades Autoinmunes/patología , Antígenos CD28/genética , Linfocitos T CD4-Positivos/inmunología , Linfocitos T CD4-Positivos/metabolismo , Linfocitos T CD4-Positivos/patología , Agregación Celular/genética , Agregación Celular/inmunología , Proteínas de Ciclo Celular/genética , Citocinas/antagonistas & inhibidores , Citocinas/biosíntesis , Células Dendríticas Foliculares/patología , Centro Germinal/inmunología , Centro Germinal/metabolismo , Centro Germinal/patología , Cambio de Clase de Inmunoglobulina/genética , Inmunoglobulina G/biosíntesis , Proteína Coestimuladora de Linfocitos T Inducibles , Ratones , Ratones Noqueados , Aglutinina de Mani/biosíntesis , Fenotipo , Proteínas Proto-Oncogénicas/deficiencia , Proteínas Proto-Oncogénicas/genética , Proteínas Proto-Oncogénicas c-cbl , Proteínas Proto-Oncogénicas c-vav , Infecciones por Rhabdoviridae/genética , Infecciones por Rhabdoviridae/inmunología , Infecciones por Rhabdoviridae/patología , Ubiquitina-Proteína Ligasas/deficiencia , Ubiquitina-Proteína Ligasas/genética , Regulación hacia Arriba/genética , Virus de la Estomatitis Vesicular Indiana/inmunologíaRESUMEN
Antigen-specific immunotolerance limits the expansion of self-reactive T cells involved in autoimmune diseases. Here, we show that the E3 ubiquitin ligase Cbl-b is upregulated in T cells after tolerizing signals. Loss of Cbl-b in mice results in impaired induction of T cell tolerance both in vitro and in vivo. Importantly, rechallenge of Cbl-b mutant mice with the tolerizing antigen results in massive lethality. Moreover, ablation of Cbl-b resulted in exacerbated autoimmunity. Mechanistically, loss of Cbl-b rescues reduced calcium mobilization of anergic T cells, which was attributed to Cbl-b-mediated regulation of PLCgamma-1 phosphorylation. Our results show a critical role for Cbl-b in the regulation of peripheral tolerance and anergy of T cells.
Asunto(s)
Proteínas Adaptadoras Transductoras de Señales , Anergia Clonal/inmunología , Linfocitos T/metabolismo , Ubiquitina-Proteína Ligasas/metabolismo , Traslado Adoptivo , Animales , Antígenos/inmunología , Anergia Clonal/fisiología , Enterotoxinas/inmunología , Técnicas In Vitro , Ratones , Fosfolipasa C gamma , Proteínas Proto-Oncogénicas c-cbl , Linfocitos T/inmunología , Fosfolipasas de Tipo C/metabolismo , Ubiquitina-Proteína Ligasas/inmunologíaRESUMEN
During the development of multicellular organisms, concerted actions of molecular signalling networks determine whether cells undergo proliferation, differentiation, death or ageing. Here we show that genetic inactivation of the stress signalling kinase, MKK7, a direct activator of JNKs in mice, results in embryonic lethality and impaired proliferation of hepatocytes. Beginning at passage 4-5, mkk7(-/-) mouse embryonic fibroblasts (MEFs) display impaired proliferation, premature senescence and G2/M cell cycle arrest. Similarly, loss of c-Jun or expression of a c-JunAA mutant in which the JNK phosphorylation sites were replaced with alanine results in a G2/M cell-cycle block. The G2/M cell-cycle kinase CDC2 was identified as a target for the MKK7-JNK-c-Jun pathway. These data show that the MKK7-JNK-c-Jun signalling pathway couples developmental and environmental cues to CDC2 expression, G2/M cell cycle progression and cellular senescence in fibroblasts.
Asunto(s)
Senescencia Celular/genética , Fase G2/genética , Hepatocitos/enzimología , Quinasas de Proteína Quinasa Activadas por Mitógenos/deficiencia , Mitosis/genética , Estrés Fisiológico/enzimología , Animales , Proteína Quinasa CDC2/metabolismo , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Células Cultivadas , Feto , Fibroblastos/citología , Fibroblastos/enzimología , Genes Letales/genética , Hepatocitos/citología , Proteínas Quinasas JNK Activadas por Mitógenos , Hígado/anomalías , Hígado/patología , MAP Quinasa Quinasa 7 , Sistema de Señalización de MAP Quinasas/genética , Ratones , Quinasas de Proteína Quinasa Activadas por Mitógenos/genética , Proteínas Quinasas Activadas por Mitógenos/metabolismo , Mutación/genética , Fosforilación , Proteínas Proto-Oncogénicas c-jun/deficiencia , Proteínas Proto-Oncogénicas c-jun/genética , Estrés Fisiológico/genéticaRESUMEN
Genetic susceptibility and autoimmunity triggered by microbial infections are factors implicated in the pathogenesis of dilated cardiomyopathy, the most common cause of heart failure in young patients. Here we show that dendritic cells (DCs) loaded with a heart-specific self peptide induce CD4+ T-cell-mediated myocarditis in nontransgenic mice. Toll-like receptor (TLR) stimulation, in concert with CD40 triggering of self peptide-loaded dendritic cells, was shown to be required for disease induction. After resolution of acute myocarditis, DC-immunized mice developed heart failure, and TLR stimulation of these mice resulted in relapse of inflammatory infiltrates. Injection of damaged, syngeneic cardiomyocytes also induced myocarditis in mice if TLRs were activated in vivo. DC-induced myocarditis provides a unifying theory as to how tissue damage and activation of TLRs during infection can induce autoimmunity, relapses and cardiomyopathy.
Asunto(s)
Autoinmunidad , Cardiomiopatía Dilatada/etiología , Cardiomiopatía Dilatada/inmunología , Células Dendríticas/inmunología , Adaptación Fisiológica , Animales , Autoantígenos/administración & dosificación , Linfocitos T CD4-Positivos/inmunología , Antígenos CD40/metabolismo , Cardiomiopatía Dilatada/genética , Cardiomiopatía Dilatada/patología , Humanos , Inmunidad Innata , Glicoproteínas de Membrana/metabolismo , Ratones , Ratones Endogámicos BALB C , Ratones Noqueados , Ratones SCID , Modelos Inmunológicos , Fragmentos de Péptidos/inmunología , Receptores de Superficie Celular/metabolismo , Receptores Toll-Like , Miosinas Ventriculares/inmunologíaRESUMEN
Dilated cardiomyopathy, resulting from myocarditis, is the most common cause of heart failure in young patients. We here show that interleukin (IL)-1 receptor type 1-deficient (IL-1R1(-/-)) mice are protected from development of autoimmune myocarditis after immunization with alpha-myosin-peptide(614-629). CD4(+) T cells from immunized IL-1R1(-/-) mice proliferated poorly and failed to transfer disease after injection into naive severe combined immunodeficiency (SCID) mice. In vitro stimulation experiments suggested that the function of IL-1R1(-/-)CD4(+) T cells was not intrinsically defect, but their activation by dendritic cells was impaired in IL-1R1(-/-) mice. Accordingly, production of tumor necrosis factor (TNF)-alpha, IL-1, IL-6, and IL-12p70 was reduced in dendritic cells lacking the IL-1 receptor type 1. In fact, injection of immature, antigen-loaded IL-1R1(+/+) but not IL-1R1(-/-) dendritic cells into IL-1R1(-/-) mice fully restored disease susceptibility by rendering IL-1R1(-/-) CD4(+) T cells pathogenic. Thus, IL-1R1 triggering is required for efficient activation of dendritic cells, which is in turn a prerequisite for induction of autoreactive CD4(+) T cells and autoimmunity.