RESUMEN
Trained innate immunity, induced via modulation of mature myeloid cells or their bone marrow progenitors, mediates sustained increased responsiveness to secondary challenges. Here, we investigated whether anti-tumor immunity can be enhanced through induction of trained immunity. Pre-treatment of mice with ß-glucan, a fungal-derived prototypical agonist of trained immunity, resulted in diminished tumor growth. The anti-tumor effect of ß-glucan-induced trained immunity was associated with transcriptomic and epigenetic rewiring of granulopoiesis and neutrophil reprogramming toward an anti-tumor phenotype; this process required type I interferon signaling irrespective of adaptive immunity in the host. Adoptive transfer of neutrophils from ß-glucan-trained mice to naive recipients suppressed tumor growth in the latter in a ROS-dependent manner. Moreover, the anti-tumor effect of ß-glucan-induced trained granulopoiesis was transmissible by bone marrow transplantation to recipient naive mice. Our findings identify a novel and therapeutically relevant anti-tumor facet of trained immunity involving appropriate rewiring of granulopoiesis.
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Granulocitos/inmunología , Inmunidad Innata , Neoplasias/inmunología , Inmunidad Adaptativa , Traslado Adoptivo , Animales , Epigénesis Genética , Interferón Tipo I/metabolismo , Ratones Endogámicos C57BL , Monocitos/metabolismo , Neoplasias/patología , Neutrófilos/metabolismo , Fenotipo , Receptor de Interferón alfa y beta/deficiencia , Receptor de Interferón alfa y beta/metabolismo , Transcripción Genética , Transcriptoma/genética , beta-Glucanos/metabolismoRESUMEN
Resolution of inflammation is essential for tissue homeostasis and represents a promising approach to inflammatory disorders. Here we found that developmental endothelial locus-1 (DEL-1), a secreted protein that inhibits leukocyte-endothelial adhesion and inflammation initiation, also functions as a non-redundant downstream effector in inflammation clearance. In human and mouse periodontitis, waning of inflammation was correlated with DEL-1 upregulation, whereas resolution of experimental periodontitis failed in DEL-1 deficiency. This concept was mechanistically substantiated in acute monosodium-urate-crystal-induced inflammation, where the pro-resolution function of DEL-1 was attributed to effective apoptotic neutrophil clearance (efferocytosis). DEL-1-mediated efferocytosis induced liver X receptor-dependent macrophage reprogramming to a pro-resolving phenotype and was required for optimal production of at least certain specific pro-resolving mediators. Experiments in transgenic mice with cell-specific overexpression of DEL-1 linked its anti-leukocyte-recruitment action to endothelial cell-derived DEL-1 and its efferocytic/pro-resolving action to macrophage-derived DEL-1. Thus, the compartmentalized expression of DEL-1 facilitates distinct homeostatic functions in an appropriate context that can be harnessed therapeutically.
Asunto(s)
Proteínas Portadoras/metabolismo , Inflamación/inmunología , Macrófagos/fisiología , Neutrófilos/inmunología , Periodontitis/inmunología , Adulto , Animales , Proteínas de Unión al Calcio , Proteínas Portadoras/genética , Moléculas de Adhesión Celular , Reprogramación Celular , Citocinas/metabolismo , Regulación de la Expresión Génica , Humanos , Inflamación/inducido químicamente , Péptidos y Proteínas de Señalización Intercelular , Células K562 , Receptores X del Hígado/metabolismo , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , FagocitosisRESUMEN
In obesity, inflammation of white adipose tissue (AT) is associated with diminished generation of beige adipocytes ('beige adipogenesis'), a thermogenic and energy-dissipating function mediated by beige adipocytes that express the uncoupling protein UCP1. Here we delineated an inflammation-driven inhibitory mechanism of beige adipogenesis in obesity that required direct adhesive interactions between macrophages and adipocytes mediated by the integrin α4 and its counter-receptor VCAM-1, respectively; expression of the latter was upregulated in obesity. This adhesive interaction reciprocally and concomitantly modulated inflammatory activation of macrophages and downregulation of UCP1 expression dependent on the kinase Erk in adipocytes. Genetic or pharmacological inactivation of the integrin α4 in mice resulted in elevated expression of UCP1 and beige adipogenesis of subcutaneous AT in obesity. Our findings, established in both mouse systems and human systems, reveal a self-sustained cycle of inflammation-driven impairment of beige adipogenesis in obesity.
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Adipocitos Beige , Adipogénesis/inmunología , Tejido Adiposo Blanco/inmunología , Diferenciación Celular/inmunología , Inflamación/inmunología , Macrófagos/inmunología , Obesidad/inmunología , Células 3T3-L1 , Adipocitos/inmunología , Adipocitos/metabolismo , Adulto , Anciano , Anciano de 80 o más Años , Animales , Adhesión Celular/inmunología , Dieta Alta en Grasa , Regulación hacia Abajo , Quinasas MAP Reguladas por Señal Extracelular/metabolismo , Retroalimentación , Femenino , Técnicas de Silenciamiento del Gen , Humanos , Immunoblotting , Integrina alfa4/genética , Macrófagos/metabolismo , Masculino , Ratones , Persona de Mediana Edad , Monocitos/inmunología , Obesidad/metabolismo , ARN Mensajero/metabolismo , Reacción en Cadena en Tiempo Real de la Polimerasa , Grasa Subcutánea , Linfocitos T/inmunología , Proteína Desacopladora 1/genética , Proteína Desacopladora 1/metabolismo , Molécula 1 de Adhesión Celular Vascular/genética , Molécula 1 de Adhesión Celular Vascular/metabolismo , Adulto JovenRESUMEN
Aging is linked to greater susceptibility to chronic inflammatory diseases, several of which, including periodontitis, involve neutrophil-mediated tissue injury. Here we found that aging-associated periodontitis was accompanied by lower expression of Del-1, an endogenous inhibitor of neutrophil adhesion dependent on the integrin LFA-1, and by reciprocal higher expression of interleukin 17 (IL-17). Consistent with that, IL-17 inhibited gingival endothelial cell expression of Del-1, thereby promoting LFA-1-dependent recruitment of neutrophils. Young Del-1-deficient mice developed spontaneous periodontitis that featured excessive neutrophil infiltration and IL-17 expression; disease was prevented in mice doubly deficient in Del-1 and LFA-1 or in Del-1 and the IL-17 receptor. Locally administered Del-1 inhibited IL-17 production, neutrophil accumulation and bone loss. Therefore, Del-1 suppressed LFA-1-dependent recruitment of neutrophils and IL-17-triggered inflammatory pathology and may thus be a promising therapeutic agent for inflammatory diseases.
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Pérdida de Hueso Alveolar/inmunología , Proteínas Portadoras/metabolismo , Interleucina-17/antagonistas & inhibidores , Interleucina-17/metabolismo , Infiltración Neutrófila/efectos de los fármacos , Periodontitis/metabolismo , Envejecimiento/inmunología , Animales , Proteínas de Unión al Calcio , Proteínas Portadoras/inmunología , Proteínas Portadoras/farmacología , Adhesión Celular/efectos de los fármacos , Moléculas de Adhesión Celular , Células Endoteliales/efectos de los fármacos , Células Endoteliales/inmunología , Femenino , Integrinas/antagonistas & inhibidores , Integrinas/inmunología , Integrinas/metabolismo , Péptidos y Proteínas de Señalización Intercelular , Interleucina-17/inmunología , Antígeno-1 Asociado a Función de Linfocito/inmunología , Antígeno-1 Asociado a Función de Linfocito/metabolismo , Masculino , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Ratones Noqueados , Infiltración Neutrófila/inmunología , Neutrófilos/inmunología , Neutrófilos/metabolismo , Atrofia Periodontal/inmunología , Atrofia Periodontal/metabolismo , Periodontitis/inmunología , Periodontitis/terapia , Receptores de Interleucina-17/deficiencia , Receptores de Interleucina-17/metabolismoRESUMEN
BACKGROUND AND AIMS: NAFLD is initiated by steatosis and can progress through fibrosis and cirrhosis to HCC. The RNA binding protein human antigen R (HuR) controls RNAs at the posttranscriptional level; hepatocyte HuR has been implicated in the regulation of diet-induced hepatic steatosis. The present study aimed to understand the role of hepatocyte HuR in NAFLD development and progression to fibrosis and HCC. APPROACH AND RESULTS: Hepatocyte-specific, HuR-deficient mice and control HuR-sufficient mice were fed either a normal diet or an NAFLD-inducing diet. Hepatic lipid accumulation, inflammation, fibrosis, and HCC development were studied by histology, flow cytometry, quantitative PCR, and RNA sequencing. The liver lipidome was characterized by lipidomics analysis, and the HuR-RNA interactions in the liver were mapped by RNA immunoprecipitation sequencing. Hepatocyte-specific, HuR-deficient mice displayed spontaneous hepatic steatosis and fibrosis predisposition compared to control HuR-sufficient mice. On an NAFLD-inducing diet, hepatocyte-specific HuR deficiency resulted in exacerbated inflammation, fibrosis, and HCC-like tumor development. A multi-omic approach, including lipidomics, transcriptomics, and RNA immunoprecipitation sequencing revealed that HuR orchestrates a protective network of hepatic-metabolic and lipid homeostasis-maintaining pathways. Consistently, HuR-deficient livers accumulated, already at steady state, a triglyceride signature resembling that of NAFLD livers. Moreover, up-regulation of secreted phosphoprotein 1 expression mediated, at least partially, fibrosis development in hepatocyte-specific HuR deficiency on an NAFLD-inducing diet, as shown by experiments using antibody blockade of osteopontin. CONCLUSIONS: HuR is a gatekeeper of liver homeostasis, preventing NAFLD-related fibrosis and HCC, suggesting that the HuR-dependent network could be exploited therapeutically.
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Carcinoma Hepatocelular , Proteína 1 Similar a ELAV , Neoplasias Hepáticas , Enfermedad del Hígado Graso no Alcohólico , Animales , Carcinoma Hepatocelular/patología , Proteína 1 Similar a ELAV/metabolismo , Homeostasis , Inflamación/metabolismo , Hígado/patología , Cirrosis Hepática/metabolismo , Neoplasias Hepáticas/patología , Ratones , Ratones Endogámicos C57BL , Enfermedad del Hígado Graso no Alcohólico/patología , ARN , Triglicéridos/metabolismoRESUMEN
Non-alcoholic fatty liver disease (NAFLD) can progress to non-alcoholic steatohepatitis (NASH), characterized by inflammation and fibrosis. Fibrosis is mediated by hepatic stellate cells (HSC) and their differentiation into activated myofibroblasts; the latter process is also promoted by inflammation. Here we studied the role of the pro-inflammatory adhesion molecule vascular cell adhesion molecule-1 (VCAM-1) in HSCs in NASH. VCAM-1 expression was upregulated in the liver upon NASH induction, and VCAM-1 was found to be present on activated HSCs. We therefore utilized HSC-specific VCAM-1-deficient and appropriate control mice to explore the role of VCAM-1 on HSCs in NASH. However, HSC-specific VCAM-1-deficient mice, as compared to control mice, did not show a difference with regards to steatosis, inflammation and fibrosis in two different models of NASH. Hence, VCAM-1 on HSCs is dispensable for NASH development and progression in mice.
Asunto(s)
Células Estrelladas Hepáticas , Enfermedad del Hígado Graso no Alcohólico , Molécula 1 de Adhesión Celular Vascular , Animales , Ratones , Células Estrelladas Hepáticas/metabolismo , Células Estrelladas Hepáticas/patología , Inflamación/metabolismo , Hígado/metabolismo , Cirrosis Hepática/metabolismo , Ratones Endogámicos C57BL , Enfermedad del Hígado Graso no Alcohólico/metabolismo , Enfermedad del Hígado Graso no Alcohólico/patología , Molécula 1 de Adhesión Celular Vascular/metabolismo , Modelos Animales de EnfermedadRESUMEN
Leukocytes are rapidly recruited to sites of inflammation via interactions with the vascular endothelium. The steroid hormone dehydroepiandrosterone (DHEA) exerts anti-inflammatory properties; however, the underlying mechanisms are poorly understood. In this study, we show that an anti-inflammatory mechanism of DHEA involves the regulation of developmental endothelial locus 1 (DEL-1) expression. DEL-1 is a secreted homeostatic factor that inhibits ß2-integrin-dependent leukocyte adhesion, and the subsequent leukocyte recruitment and its expression is downregulated upon inflammation. Similarly, DHEA inhibited leukocyte adhesion to the endothelium in venules of the inflamed mouse cremaster muscle. Importantly, in a model of lung inflammation, DHEA limited neutrophil recruitment in a DEL-1-dependent manner. Mechanistically, DHEA counteracted the inhibitory effect of inflammation on DEL-1 expression. Indeed, whereas TNF reduced DEL-1 expression and secretion in endothelial cells by diminishing C/EBPß binding to the DEL-1 gene promoter, DHEA counteracted the inhibitory effect of TNF via activation of tropomyosin receptor kinase A (TRKA) and downstream PI3K/AKT signaling that restored C/EBPß binding to the DEL-1 promoter. In conclusion, DHEA restrains neutrophil recruitment by reversing inflammation-induced downregulation of DEL-1 expression. Therefore, the anti-inflammatory DHEA/DEL-1 axis could be harnessed therapeutically in the context of inflammatory diseases.
Asunto(s)
Proteínas de Unión al Calcio/inmunología , Moléculas de Adhesión Celular/inmunología , Deshidroepiandrosterona/farmacología , Leucocitos/inmunología , Transducción de Señal/inmunología , Animales , Proteína beta Potenciadora de Unión a CCAAT/inmunología , Antígenos CD18/inmunología , Adhesión Celular/inmunología , Endotelio Vascular/inmunología , Femenino , Regulación de la Expresión Génica/inmunología , Leucocitos/citología , Ratones , Fosfatidilinositol 3-Quinasas/inmunología , Regiones Promotoras Genéticas/inmunología , Proteínas Proto-Oncogénicas c-akt/inmunología , Receptor trkA/inmunologíaRESUMEN
The mechanism underlying vasoproliferative retinopathies like retinopathy of prematurity (ROP) is hypoxia-triggered neovascularisation. Nerve growth factor (NGF), a neurotrophin supporting survival and differentiation of neuronal cells may also regulate endothelial cell functions. Here we studied the role of NGF in pathological retinal angiogenesis in the course of the ROP mouse model. Topical application of NGF enhanced while intraocular injections of anti-NGF neutralizing antibody reduced pathological retinal vascularization in mice subjected to the ROP model. The pro-angiogenic effect of NGF in the retina was mediated by inhibition of retinal endothelial cell apoptosis. In vitro, NGF decreased the intrinsic (mitochondria-dependent) apoptosis in hypoxia-treated human retinal microvascular endothelial cells and preserved the mitochondrial membrane potential. The anti-apoptotic effect of NGF was associated with increased BCL2 and reduced BAX, as well as with enhanced ERK and AKT phosphorylation, and was abolished by inhibition of the AKT pathway. Our findings reveal an anti-apoptotic role of NGF in the hypoxic retinal endothelium, which is involved in promoting pathological retinal vascularization, thereby pointing to NGF as a potential target for proliferative retinopathies.
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Anticuerpos Neutralizantes/farmacología , Neovascularización Patológica/terapia , Factor de Crecimiento Nervioso/antagonistas & inhibidores , Retinopatía de la Prematuridad/terapia , Apoptosis/efectos de los fármacos , Células Endoteliales , Humanos , Inyecciones Intraoculares , Potencial de la Membrana Mitocondrial/efectos de los fármacos , Neovascularización Patológica/genética , Neovascularización Patológica/patología , Factor de Crecimiento Nervioso/genética , Neuronas/efectos de los fármacos , Neuronas/patología , Proteínas Proto-Oncogénicas c-bcl-2/genética , Retina/efectos de los fármacos , Retina/patología , Retinopatía de la Prematuridad/genética , Retinopatía de la Prematuridad/patología , Proteína X Asociada a bcl-2/genéticaRESUMEN
Immune cells are present in the adipose tissue (AT) and regulate its function. Under lean conditions, immune cells predominantly of type 2 immunity, including eosinophils, M2-like anti-inflammatory macrophages and innate lymphoid cells 2, contribute to the maintenance of metabolic homeostasis within the AT. In the course of obesity, pro-inflammatory immune cells, such as M1-like macrophages, prevail in the AT. Inflammation in the obese AT is associated with the development of metabolic complications such as insulin resistance, type 2 diabetes and cardiovascular disease. Thus, the immune cell-adipocyte crosstalk in the AT is an important regulator of AT function and systemic metabolism. We discuss herein this crosstalk with a special focus on the role of innate immune cells in AT inflammation and metabolic homeostasis in obesity.
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Tejido Adiposo , Células Dendríticas , Inmunidad Innata , Inflamación , Leucocitos , Macrófagos , Obesidad , Tejido Adiposo/inmunología , Tejido Adiposo/metabolismo , Células Dendríticas/inmunología , Células Dendríticas/metabolismo , Humanos , Inmunidad Innata/inmunología , Inflamación/inmunología , Inflamación/metabolismo , Leucocitos/inmunología , Leucocitos/metabolismo , Macrófagos/inmunología , Macrófagos/metabolismo , Obesidad/inmunología , Obesidad/metabolismoRESUMEN
The immune system plays an instrumental role in obesity and insulin resistance. Here, we unravel the role of the costimulatory molecule CD40 and its signaling intermediates, TNF receptor-associated factors (TRAFs), in diet-induced obesity (DIO). Although not exhibiting increased weight gain, male CD40(-/-) mice in DIO displayed worsened insulin resistance, compared with wild-type mice. This worsening was associated with excessive inflammation of adipose tissue (AT), characterized by increased accumulation of CD8(+) T cells and M1 macrophages, and enhanced hepatosteatosis. Mice with deficient CD40-TRAF2/3/5 signaling in MHCII(+) cells exhibited a similar phenotype in DIO as CD40(-/-) mice. In contrast, mice with deficient CD40-TRAF6 signaling in MHCII(+) cells displayed no insulin resistance and showed a reduction in both AT inflammation and hepatosteatosis in DIO. To prove the therapeutic potential of inhibition of CD40-TRAF6 in obesity, DIO mice were treated with a small-molecule inhibitor that we designed to specifically block CD40-TRAF6 interactions; this compound improved insulin sensitivity, reduced AT inflammation, and decreased hepatosteatosis. Our study reveals that the CD40-TRAF2/3/5 signaling pathway in MHCII(+) cells protects against AT inflammation and metabolic complications associated with obesity whereas CD40-TRAF6 interactions in MHCII(+) cells aggravate these complications. Inhibition of CD40-TRAF6 signaling by our compound may provide a therapeutic option in obesity-associated insulin resistance.
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Antígenos CD40/metabolismo , Resistencia a la Insulina/inmunología , Obesidad/inmunología , Transducción de Señal/inmunología , Factor 6 Asociado a Receptor de TNF/metabolismo , Tejido Adiposo/citología , Tejido Adiposo/inmunología , Tejido Adiposo/patología , Análisis de Varianza , Animales , Compuestos Azo , Antígenos CD40/antagonistas & inhibidores , Antígenos CD40/genética , Linfocitos T CD8-positivos/inmunología , Calorimetría , Hígado Graso/etiología , Hígado Graso/patología , Citometría de Flujo , Ligandos , Espectroscopía de Resonancia Magnética , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Obesidad/complicaciones , Reacción en Cadena en Tiempo Real de la Polimerasa , Transducción de Señal/efectos de los fármacos , Resonancia por Plasmón de Superficie , Factor 6 Asociado a Receptor de TNF/antagonistas & inhibidoresRESUMEN
Inflammation in the central nervous system (CNS) and disruption of its immune privilege are major contributors to the pathogenesis of multiple sclerosis (MS) and of its rodent counterpart, experimental autoimmune encephalomyelitis (EAE). We have previously identified developmental endothelial locus-1 (Del-1) as an endogenous anti-inflammatory factor, which inhibits integrin-dependent leukocyte adhesion. Here we show that Del-1 contributes to the immune privilege status of the CNS. Intriguingly, Del-1 expression decreased in chronic-active MS lesions and in the inflamed CNS in the course of EAE. Del-1-deficiency was associated with increased EAE severity, accompanied by increased demyelination and axonal loss. As compared with control mice, Del-1(-/-) mice displayed enhanced disruption of the blood-brain barrier and increased infiltration of neutrophil granulocytes in the spinal cord in the course of EAE, accompanied by elevated levels of inflammatory cytokines, including interleukin-17 (IL-17). The augmented levels of IL-17 in Del-1-deficiency derived predominantly from infiltrated CD8(+) T cells. Increased EAE severity and neutrophil infiltration because of Del-1-deficiency was reversed in mice lacking both Del-1 and IL-17 receptor, indicating a crucial role for the IL-17/neutrophil inflammatory axis in EAE pathogenesis in Del-1(-/-) mice. Strikingly, systemic administration of Del-1-Fc ameliorated clinical relapse in relapsing-remitting EAE. Therefore, Del-1 is an endogenous homeostatic factor in the CNS protecting from neuroinflammation and demyelination. Our findings provide mechanistic underpinnings for the previous implication of Del-1 as a candidate MS susceptibility gene and suggest that Del-1-centered therapeutic approaches may be beneficial in neuroinflammatory and demyelinating disorders.
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Axones/metabolismo , Barrera Hematoencefálica/metabolismo , Proteínas Portadoras/metabolismo , Vaina de Mielina/metabolismo , Neuroinmunomodulación/fisiología , Médula Espinal/metabolismo , Animales , Axones/efectos de los fármacos , Axones/patología , Barrera Hematoencefálica/efectos de los fármacos , Barrera Hematoencefálica/patología , Proteínas de Unión al Calcio , Permeabilidad Capilar/efectos de los fármacos , Permeabilidad Capilar/fisiología , Proteínas Portadoras/genética , Moléculas de Adhesión Celular , Encefalomielitis Autoinmune Experimental/tratamiento farmacológico , Encefalomielitis Autoinmune Experimental/metabolismo , Encefalomielitis Autoinmune Experimental/patología , Femenino , Granulocitos/efectos de los fármacos , Granulocitos/metabolismo , Granulocitos/patología , Homeostasis/efectos de los fármacos , Homeostasis/fisiología , Péptidos y Proteínas de Señalización Intercelular , Interleucina-17/metabolismo , Ratones Endogámicos C57BL , Ratones Noqueados , Vaina de Mielina/efectos de los fármacos , Vaina de Mielina/patología , Neuroinmunomodulación/efectos de los fármacos , Neutrófilos/efectos de los fármacos , Neutrófilos/metabolismo , Neutrófilos/patología , Receptores de Interleucina-17/genética , Receptores de Interleucina-17/metabolismo , Índice de Severidad de la Enfermedad , Médula Espinal/efectos de los fármacos , Médula Espinal/patologíaRESUMEN
UNLABELLED: The low-grade inflammatory state present in obesity contributes to obesity-related metabolic dysregulation, including nonalcoholic steatohepatitis (NASH) and insulin resistance. Intercellular interactions between immune cells or between immune cells and hepatic parenchymal cells contribute to the exacerbation of liver inflammation and steatosis in obesity. The costimulatory molecules, B7.1 and B7.2, are important regulators of cell-cell interactions in several immune processes; however, the role of B7 costimulation in obesity-related liver inflammation is unknown. Here, diet-induced obesity (DIO) studies in mice with genetic inactivation of both B7.1 and B7.2 (double knockout; DKO) revealed aggravated obesity-related metabolic dysregulation, reduced insulin signalling in the liver and adipose tissue (AT), glucose intolerance, and enhanced progression to steatohepatitis resulting from B7.1/B7.2 double deficiency. The metabolic phenotype of B7.1/B7.2 double deficiency upon DIO was accompanied by increased hepatic and AT inflammation, associated with largely reduced numbers of regulatory T cells (Tregs) in these organs. In order to assess the role of B7 costimulation in DIO in a non-Treg-lacking environment, we performed antibody (Ab)-mediated inhibition of B7 molecules in wild-type mice in DIO. Antibody-blockade of both B7.1 and B7.2 improved the metabolic phenotype of DIO mice, which was linked to amelioration of hepatic steatosis and reduced inflammation in liver and AT. CONCLUSION: Our study demonstrates a dual role of B7 costimulation in the course of obesity-related sequelae, particularly NASH. The genetic inactivation of B7.1/B7.2 deteriorates obesity-related liver steatosis and metabolic dysregulation, likely a result of the intrinsic absence of Tregs in these mice, rendering DKO mice a novel murine model of NASH. In contrast, inhibition of B7 costimulation under conditions where Tregs are present may provide a novel therapeutic approach for obesity-related metabolic dysregulation and, especially, NASH.
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Antígenos B7/fisiología , Síndrome Metabólico/fisiopatología , Enfermedad del Hígado Graso no Alcohólico/fisiopatología , Obesidad/fisiopatología , Animales , Antígenos B7/deficiencia , Antígenos B7/genética , Comunicación Celular/fisiología , Modelos Animales de Enfermedad , Hígado/patología , Masculino , Ratones , Ratones Noqueados , Fenotipo , Linfocitos T Reguladores/patologíaRESUMEN
Obese adipose tissue (AT) inflammation contributes critically to development of insulin resistance. The complement anaphylatoxin C5a receptor (C5aR) has been implicated in inflammatory processes and as regulator of macrophage activation and polarization. However, the role of C5aR in obesity and AT inflammation has not been addressed. We engaged the model of diet-induced obesity and found that expression of C5aR was significantly upregulated in the obese AT, compared with lean AT. In addition, C5a was present in obese AT in the proximity of macrophage-rich crownlike structures. C5aR-sufficient and -deficient mice were fed a high-fat diet (HFD) or a normal diet (ND). C5aR deficiency was associated with increased AT weight upon ND feeding in males, but not in females, and with increased adipocyte size upon ND and HFD conditions in males. However, obese C5aR(-/-) mice displayed improved systemic and AT insulin sensitivity. Improved AT insulin sensitivity in C5aR(-/-) mice was associated with reduced accumulation of total and proinflammatory M1 macrophages in the obese AT, increased expression of IL-10, and decreased AT fibrosis. In contrast, no difference in ß cell mass was observed owing to C5aR deficiency under an HFD. These results suggest that C5aR contributes to macrophage accumulation and M1 polarization in the obese AT and thereby to AT dysfunction and development of AT insulin resistance.
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Tejido Adiposo/inmunología , Tejido Adiposo/metabolismo , Resistencia a la Insulina/inmunología , Macrófagos/inmunología , Receptor de Anafilatoxina C5a/metabolismo , Adipocitos/inmunología , Adipocitos/metabolismo , Animales , Complemento C5a/metabolismo , Grasas de la Dieta/inmunología , Grasas de la Dieta/metabolismo , Femenino , Fibrosis/inmunología , Inflamación/inmunología , Células Secretoras de Insulina/metabolismo , Interleucina-10/biosíntesis , Activación de Macrófagos/inmunología , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Obesidad/inmunología , Obesidad/metabolismo , Receptor de Anafilatoxina C5a/biosíntesis , Receptor de Anafilatoxina C5a/inmunología , Regulación hacia ArribaRESUMEN
RATIONALE: Multiple sclerosis (MS) and its mouse model, experimental autoimmune encephalomyelitis (EAE), are inflammatory disorders of the central nervous system (CNS). The function of platelets in inflammatory and autoimmune pathologies is thus far poorly defined. OBJECTIVE: We addressed the role of platelets in mediating CNS inflammation in EAE. METHODS AND RESULTS: We found that platelets were present in human MS lesions as well as in the CNS of mice subjected to EAE but not in the CNS from control nondiseased mice. Platelet depletion at the effector-inflammatory phase of EAE in mice resulted in significantly ameliorated disease development and progression. EAE suppression on platelet depletion was associated with reduced recruitment of leukocytes to the inflamed CNS, as assessed by intravital microscopy, and with a blunted inflammatory response. The platelet-specific receptor glycoprotein Ibα (GPIbα) promotes both platelet adhesion and inflammatory actions of platelets and targeting of GPIbα attenuated EAE in mice. Moreover, targeting another platelet adhesion receptor, glycoprotein IIb/IIIa (GPIIb/IIIa), also reduced EAE severity in mice. CONCLUSIONS: Platelets contribute to the pathogenesis of EAE by promoting CNS inflammation. Targeting platelets may therefore represent an important new therapeutic approach for MS treatment.
Asunto(s)
Plaquetas/metabolismo , Sistema Nervioso Central/metabolismo , Encefalomielitis Autoinmune Experimental/sangre , Leucocitos/inmunología , Animales , Antiinflamatorios/farmacología , Plaquetas/efectos de los fármacos , Plaquetas/inmunología , Células Cultivadas , Sistema Nervioso Central/efectos de los fármacos , Sistema Nervioso Central/inmunología , Encefalomielitis Autoinmune Experimental/tratamiento farmacológico , Encefalomielitis Autoinmune Experimental/inmunología , Femenino , Humanos , Mediadores de Inflamación/metabolismo , Leucocitos/efectos de los fármacos , Glicoproteínas de Membrana/antagonistas & inhibidores , Glicoproteínas de Membrana/sangre , Ratones , Ratones Endogámicos C57BL , Adhesividad Plaquetaria , Inhibidores de Agregación Plaquetaria/farmacología , Complejo GPIIb-IIIa de Glicoproteína Plaquetaria/antagonistas & inhibidores , Complejo GPIIb-IIIa de Glicoproteína Plaquetaria/metabolismo , Complejo GPIb-IX de Glicoproteína Plaquetaria/antagonistas & inhibidores , Complejo GPIb-IX de Glicoproteína Plaquetaria/metabolismo , Factores de TiempoRESUMEN
Formyl peptide receptor 2 (FPR2) is a receptor for formylated peptides and specific pro-resolving mediators, and is involved in various inflammatory processes. Here, we aimed to elucidate the role of FPR2 in dendritic cell (DC) function and autoimmunity-related central nervous system (CNS) inflammation by using the experimental autoimmune encephalomyelitis (EAE) model. EAE induction was accompanied by increased Fpr2 mRNA expression in the spinal cord. FPR2-deficient (Fpr2 KO) mice displayed delayed onset of EAE compared to wild-type (WT) mice, associated with reduced frequencies of Th17 cells in the inflamed spinal cord at the early stage of the disease. However, FPR2 deficiency did not affect EAE severity after the disease reached its peak. FPR2 deficiency in mature DCs resulted in decreased expression of Th17 polarizing cytokines IL6, IL23p19, IL1ß, and thereby diminished the DC-mediated activation of Th17 cell differentiation. LPS-activated FPR2-deficient DCs showed upregulated Nos2 expression and nitric oxide (NO) production, as well as reduced oxygen consumption rate and impaired mitochondrial function, including decreased mitochondrial superoxide levels, lower mitochondrial membrane potential and diminished expression of genes related to the tricarboxylic acid cycle and genes related to the electron transport chain, as compared to WT DCs. Treatment with a NO inhibitor reversed the reduced Th17 cell differentiation in the presence of FPR2-deficient DCs. Together, by regulating DC metabolism, FPR2 enhances the production of DC-derived Th17-polarizing cytokines and hence Th17 cell differentiation in the context of neuroinflammation.
Asunto(s)
Diferenciación Celular , Células Dendríticas , Encefalomielitis Autoinmune Experimental , Ratones Noqueados , Receptores de Formil Péptido , Células Th17 , Animales , Células Dendríticas/inmunología , Células Dendríticas/metabolismo , Receptores de Formil Péptido/genética , Receptores de Formil Péptido/metabolismo , Células Th17/inmunología , Células Th17/metabolismo , Ratones , Encefalomielitis Autoinmune Experimental/inmunología , Encefalomielitis Autoinmune Experimental/metabolismo , Ratones Endogámicos C57BL , Citocinas/metabolismo , Enfermedades Neuroinflamatorias/inmunología , Enfermedades Neuroinflamatorias/metabolismo , Femenino , Médula Espinal/inmunología , Médula Espinal/metabolismoRESUMEN
Insulin resistance (IR) during obesity is linked to adipose tissue macrophage (ATM)-driven inflammation of adipose tissue. Whether anti-inflammatory glucocorticoids (GCs) at physiological levels modulate IR is unclear. Here, we report that deletion of the GC receptor (GR) in myeloid cells, including macrophages in mice, aggravates obesity-related IR by enhancing adipose tissue inflammation due to decreased anti-inflammatory ATM leading to exaggerated adipose tissue lipolysis and severe hepatic steatosis. In contrast, GR deletion in Kupffer cells alone does not alter IR. Co-culture experiments show that the absence of GR in macrophages directly causes reduced phospho-AKT and glucose uptake in adipocytes, suggesting an important function of GR in ATM. GR-deficient macrophages are refractory to alternative ATM-inducing IL-4 signaling, due to reduced STAT6 chromatin loading and diminished anti-inflammatory enhancer activation. We demonstrate that GR has an important function in macrophages during obesity by limiting adipose tissue inflammation and lipolysis to promote insulin sensitivity.
Asunto(s)
Glucocorticoides , Resistencia a la Insulina , Animales , Ratones , Glucocorticoides/farmacología , Resistencia a la Insulina/genética , Antiinflamatorios/farmacología , Tejido Adiposo , Macrófagos , Obesidad/genética , Inflamación , Ratones Endogámicos C57BLRESUMEN
Progressive accrual of senescent cells in aging and chronic diseases is associated with detrimental effects in tissue homeostasis. We found that senescent fibroblasts and epithelia were not only refractory to macrophage-mediated engulfment and removal, but they also paralyzed the ability of macrophages to remove bystander apoptotic corpses. Senescent cell-mediated efferocytosis suppression (SCES) was independent of the senescence-associated secretory phenotype (SASP) but instead required direct contact between macrophages and senescent cells. SCES involved augmented senescent cell expression of CD47 coinciding with increased CD47-modifying enzymes QPCT/L. SCES was reversible by interfering with the SIRPα-CD47-SHP-1 axis or QPCT/L activity. While CD47 expression increased in human and mouse senescent cells in vitro and in vivo, another ITIM-containing protein, CD24, contributed to SCES specifically in human epithelial senescent cells where it compensated for genetic deficiency in CD47. Thus, CD47 and CD24 link the pathogenic effects of senescent cells to homeostatic macrophage functions, such as efferocytosis, which we hypothesize must occur efficiently to maintain tissue homeostasis.
Asunto(s)
Apoptosis , Antígeno CD47 , Macrófagos , Fenotipo Secretor Asociado a la Senescencia , Animales , Humanos , Ratones , Aminoaciltransferasas/metabolismo , Antígeno CD24/metabolismo , Antígeno CD47/genética , Antígeno CD47/metabolismo , Macrófagos/citología , Regulación hacia ArribaRESUMEN
Peroxiredoxin II (Prdx II, a typical 2-Cys Prdx) has been originally isolated from erythrocytes, and its structure and peroxidase activity have been adequately studied. Mice lacking Prdx II proteins had heinz bodies in their peripheral blood, and morphologically abnormal cells were detected in the dense red blood cell (RBC) fractions, which contained markedly higher levels of reactive oxygen species (ROS). In this study, a labeling experiment with the thiol-modifying reagent biotinylated iodoacetamide (BIAM) in Prdx II-/- mice revealed that a variety of RBC proteins were highly oxidized. To identify oxidation-sensitive proteins in Prdx II-/- mice, we performed RBC comparative proteome analysis in membrane and cytosolic fractions by nano-UPLC-MSE shotgun proteomics. We found oxidation-sensitive 54 proteins from 61 peptides containing cysteine oxidation, and analyzed comparative expression pattern in healthy RBCs of Prdx II+/+ mice, healthy RBCs of Prdx II-/- mice, and abnormal RBCs of Prdx II-/- mice. These proteins belonged to cellular functions related with RBC lifespan maintain, such as cytoskeleton, stress-induced proteins, metabolic enzymes, signal transduction, and transporters. Furthermore, protein networks among identified oxidation-sensitive proteins were analyzed to associate with various diseases. Consequently, we expected that RBC proteome might provide clues to understand redox-imbalanced diseases.
Asunto(s)
Cisteína/metabolismo , Eritrocitos/metabolismo , Peroxirredoxinas/genética , Proteoma/metabolismo , Secuencia de Aminoácidos , Animales , Proteínas del Citoesqueleto/química , Proteínas del Citoesqueleto/metabolismo , Eritrocitos/enzimología , Técnicas de Inactivación de Genes , Homeostasis , Yodoacetamida/química , Espectrometría de Masas , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Datos de Secuencia Molecular , Oxidación-Reducción , Fragmentos de Péptidos/química , Peroxirredoxinas/metabolismo , Mapas de Interacción de Proteínas , Proteoma/químicaRESUMEN
Beyond its role in immunity, complement mediates a wide range of functions in the context of morphogenetic or tissue remodeling processes. Angiogenesis is crucial during tissue remodeling in multiple pathologies; however, the knowledge about the regulation of neovascularization by the complement components is scarce. Here we studied the involvement of complement in pathological angiogenesis. Strikingly, we found that mice deficient in the central complement component C3 displayed increased neovascularization in the model of retinopathy of prematurity (ROP) and in the in vivo Matrigel plug assay. In addition, antibody-mediated blockade of C5, treatment with C5aR antagonist, or C5aR deficiency in mice resulted in enhanced pathological retina angiogenesis. While complement did not directly affect angiogenesis-related endothelial cell functions, we found that macrophages mediated the antiangiogenic activity of complement. In particular, C5a-stimulated macrophages were polarized toward an angiogenesis-inhibitory phenotype, including the up-regulated secretion of the antiangiogenic soluble vascular endothelial growth factor receptor-1. Consistently, macrophage depletion in vivo reversed the increased neovascularization associated with C3- or C5aR deficiency. Taken together, complement and in particular the C5a-C5aR axes are potent inhibitors of angiogenesis.
Asunto(s)
Complemento C3/inmunología , Complemento C5/inmunología , Inmunidad Innata , Neovascularización Patológica/inmunología , Retina/patología , Retinopatía de la Prematuridad/inmunología , Animales , Técnicas de Cultivo de Célula , Línea Celular , Complemento C3/genética , Complemento C5a/inmunología , Eliminación de Gen , Humanos , Recién Nacido , Macrófagos/inmunología , Ratones , Ratones Endogámicos C57BL , Neovascularización Patológica/patología , Receptor de Anafilatoxina C5a/genética , Receptor de Anafilatoxina C5a/inmunología , Retina/inmunología , Retinopatía de la Prematuridad/patología , Factores de Crecimiento Endotelial Vascular/inmunologíaRESUMEN
Nonalcoholic fatty liver disease (NAFLD) is a very common hepatic pathology featuring steatosis and is linked to obesity and related conditions, such as the metabolic syndrome. When hepatic steatosis is accompanied by inflammation, the disorder is defined as nonalcoholic steatohepatitis (NASH), which in turn can progress toward fibrosis development that can ultimately result in cirrhosis. Cells of innate immunity, such as neutrophils or macrophages, are central regulators of NASH-related inflammation. Recent studies utilizing new experimental technologies, such as single-cell RNA sequencing, have revealed substantial heterogeneity within the macrophage populations of the liver, suggesting distinct functions of liver-resident Kupffer cells and recruited monocyte-derived macrophages with regards to regulation of liver inflammation and progression of NASH pathogenesis. Herein, we discuss recent developments concerning the function of innate immune cell subsets in NAFLD and NASH.