RESUMEN
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.
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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.
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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
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.
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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
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.
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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
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
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.
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Enfermedad del Hígado Graso no Alcohólico , Humanos , Inmunidad Innata , Macrófagos del Hígado , Hígado , MacrófagosRESUMEN
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
FOXP3+CD4+ regulatory T cells (Tregs) are critical for immune homeostasis and respond to local tissue cues, which control their stability and function. We explored here whether developmental endothelial locus-1 (DEL-1), which, like Tregs, increases during resolution of inflammation, promotes Treg responses. DEL-1 enhanced Treg numbers and function at barrier sites (oral and lung mucosa). The underlying mechanism was dissected using mice lacking DEL-1 or expressing a point mutant thereof, or mice with T cell-specific deletion of the transcription factor RUNX1, identified by RNA sequencing analysis of the DEL-1-induced Treg transcriptome. Specifically, through interaction with αvß3 integrin, DEL-1 promoted induction of RUNX1-dependent FOXP3 expression and conferred stability of FOXP3 expression upon Treg restimulation in the absence of exogenous TGF-ß1. Consistently, DEL-1 enhanced the demethylation of the Treg-specific demethylated region (TSDR) in the mouse Foxp3 gene and the suppressive function of sorted induced Tregs. Similarly, DEL-1 increased RUNX1 and FOXP3 expression in human conventional T cells, promoting their conversion into induced Tregs with increased TSDR demethylation, enhanced stability, and suppressive activity. We thus uncovered a DEL-1/αvß3/RUNX1 axis that promotes Treg responses at barrier sites and offers therapeutic options for modulating inflammatory/autoimmune disorders.
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Proteínas de Unión al Calcio/inmunología , Moléculas de Adhesión Celular/inmunología , Integrina beta3/inmunología , Transducción de Señal/inmunología , Linfocitos T Reguladores/inmunología , Animales , Proteínas de Unión al Calcio/genética , Moléculas de Adhesión Celular/genética , Subunidad alfa 2 del Factor de Unión al Sitio Principal/genética , Subunidad alfa 2 del Factor de Unión al Sitio Principal/inmunología , Humanos , Inflamación/genética , Inflamación/inmunología , Inflamación/patología , Integrina beta3/genética , Ratones , Ratones Noqueados , Transducción de Señal/genética , Linfocitos T Reguladores/patología , Factor de Crecimiento Transformador beta1/genética , Factor de Crecimiento Transformador beta1/inmunología , Factor de Crecimiento Transformador beta2/genética , Factor de Crecimiento Transformador beta2/inmunologíaRESUMEN
Adipose progenitor cells, or preadipocytes, constitute a small population of immature cells within the adipose tissue. They are a heterogeneous group of cells, in which different subtypes have a varying degree of commitment toward diverse cell fates, contributing to white and beige adipogenesis, fibrosis or maintenance of an immature cell phenotype with proliferation capacity. Mature adipocytes as well as cells of the immune system residing in the adipose tissue can modulate the function and differentiation potential of preadipocytes in a contact- and/or paracrine-dependent manner. In the course of obesity, the accumulation of immune cells within the adipose tissue contributes to the development of a pro-inflammatory microenvironment in the tissue. Under such circumstances, the crosstalk between preadipocytes and immune or parenchymal cells of the adipose tissue may critically regulate the differentiation of preadipocytes into white adipocytes, beige adipocytes, or myofibroblasts, thereby influencing adipose tissue expansion and adipose tissue dysfunction, including downregulation of beige adipogenesis and development of fibrosis. The present review will outline the current knowledge about factors shaping cell fate decisions of adipose progenitor cells in the context of obesity-related inflammation.
RESUMEN
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.
Asunto(s)
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
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
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
Although accumulation of lymphocytes in the white adipose tissue (WAT) in obesity is linked to insulin resistance, it remains unclear whether lymphocytes also participate in the regulation of energy homeostasis in the WAT. Here, we demonstrate enhanced energy dissipation in Rag1-/- mice, increased catecholaminergic input to subcutaneous WAT, and significant beige adipogenesis. Adoptive transfer experiments demonstrated that CD8+ T cell deficiency accounts for the enhanced beige adipogenesis in Rag1-/- mice. Consistently, we identified that CD8-/- mice also presented with enhanced beige adipogenesis. The inhibitory effect of CD8+ T cells on beige adipogenesis was reversed by blockade of IFN-γ. All together, our findings identify an effect of CD8+ T cells in regulating energy dissipation in lean WAT, mediated by IFN-γ modulation of the abundance of resident immune cells and of local catecholaminergic activity. Our results provide a plausible explanation for the clinical signs of metabolic dysfunction in diseases characterized by altered CD8+ T cell abundance and suggest targeting of CD8+ T cells as a promising therapeutic approach for obesity and other diseases with altered energy homeostasis.
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Adipogénesis/fisiología , Tejido Adiposo Beige/metabolismo , Linfocitos T CD8-positivos/metabolismo , Metabolismo Energético/inmunología , Obesidad/metabolismo , Tejido Adiposo Beige/citología , Tejido Adiposo Beige/inmunología , Tejido Adiposo Blanco/citología , Tejido Adiposo Blanco/inmunología , Tejido Adiposo Blanco/metabolismo , Traslado Adoptivo , Animales , Antígenos CD8/genética , Antígenos CD8/metabolismo , Linfocitos T CD8-positivos/inmunología , Linfocitos T CD8-positivos/trasplante , Diferenciación Celular/fisiología , Modelos Animales de Enfermedad , Proteínas de Homeodominio/genética , Proteínas de Homeodominio/metabolismo , Humanos , Interferón gamma/genética , Interferón gamma/metabolismo , Metabolismo de los Lípidos/fisiología , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Modelos Animales , Obesidad/genética , Obesidad/inmunologíaRESUMEN
Limited literature exists on the association between androgen deprivation therapy (ADT) for prostate cancer (PCa) and subsequent dementia and the study conclusions are in conflicts with one another. We searched several cohort databases from 1960 to 2017 for observational or prospective studies that reported on an association between ADT for PCa and subsequent dementia. A meta-analysis was performed to cumulatively determine the association between ADT and dementia including Alzheimer's disease using an incidence rate ratio (IRR), crude hazard ratio (HR), and adjusted HR. Seven studies were eligible for the meta-analysis, with the inclusion of a total of 90, 543 prostate cancer patients. The pooled overall IRR, crude HR, and adjusted HR were 1.78 [95% confidence interval (CI): 1.51-2.10)], 1.80 (95% CI: 1.05-3.10), and 1.59 (95% CI: 1.16-2.18), respectively. A meta-regression analysis showed that the crude HR was affected by both follow -up duration and lag time in the univariate model (p = < 0.001). However, IRR and adjusted HR were not affected by these moderators. The overall outcomes of IRR, crude HR, and adjusted HR were found to be balanced in the sensitivity analysis. A positive association was demonstrated between ADT and the subsequent incidence of dementia in this meta-analysis. Methodological difference including follow-up duration and the time lag could be related with the discrepancies.
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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
Obesity-related adipose tissue (AT) inflammation that promotes metabolic dysregulation is associated with increased AT mast cell numbers. Mast cells are potent inducers of inflammatory responses and could potentially contribute to obesity-induced AT inflammation and metabolic dysregulation. Conflicting findings were reported on obesity-related metabolic dysfunction in mast cell-deficient mice, thus creating a controversy that has not been resolved to date. Whereas traditional Kit hypomorphic mast cell-deficient strains featured reduced diet-induced obesity and diabetes, a Kit-independent model of mast cell deficiency, Cpa3Cre/+ mice, displayed no alterations in obesity and insulin sensitivity. Herein, we analyzed diet-induced obesity in Mcpt5-Cre R-DTA mice, in which the lack of mast cells is caused by a principle different from mast cell deficiency in Cpa3Cre/+ mice or Kit mutations. We observed no difference between mast cell-deficient and -proficient mice in diet-induced obesity with regards to weight gain, glucose tolerance, insulin resistance, metabolic parameters, hepatic steatosis, and AT or liver inflammation. We conclude that mast cells play no essential role in obesity and related pathologies.
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Angiogenesis is a central regulator for white (WAT) and brown (BAT) adipose tissue adaptation in the course of obesity. Here we show that deletion of hypoxia-inducible factor 2α (HIF2α) in adipocytes (by using Fabp4-Cre transgenic mice) but not in myeloid or endothelial cells negatively impacted WAT angiogenesis and promoted WAT inflammation, WAT dysfunction, hepatosteatosis, and systemic insulin resistance in obesity. Importantly, adipocyte HIF2α regulated vascular endothelial growth factor (VEGF) expression and angiogenesis of obese BAT as well as its thermogenic function. Consistently, obese adipocyte-specific HIF2α-deficient mice displayed BAT dysregulation, associated with reduced levels of uncoupling protein 1 (UCP1) and a dysfunctional thermogenic response to cold exposure. VEGF administration reversed WAT and BAT inflammation and BAT dysfunction in adipocyte HIF2α-deficient mice. Together, our findings show that adipocyte HIF2α is protective against maladaptation to obesity and metabolic dysregulation by promoting angiogenesis in both WAT and BAT and by counteracting obesity-mediated BAT dysfunction.
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Adipocitos/patología , Tejido Adiposo Pardo/fisiopatología , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/genética , Eliminación de Gen , Obesidad/genética , Obesidad/fisiopatología , Adipocitos/metabolismo , Tejido Adiposo Pardo/irrigación sanguínea , Tejido Adiposo Pardo/metabolismo , Animales , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/metabolismo , Inflamación/complicaciones , Canales Iónicos/metabolismo , Masculino , Ratones , Ratones Noqueados , Proteínas Mitocondriales/metabolismo , Neovascularización Fisiológica , Obesidad/complicaciones , Obesidad/metabolismo , Termogénesis , Proteína Desacopladora 1 , Factor A de Crecimiento Endotelial Vascular/metabolismoRESUMEN
Myeloid-related proteins (MRPs) 8 and 14 are cytosolic proteins secreted from myeloid cells as proinflammatory mediators. Currently, the functional role of circulating extracellular MRP8/14 is unclear. Our present study identifies extracellular MRP8/14 as an autocrine player in the leukocyte adhesion cascade. We show that E-selectin-PSGL-1 interaction during neutrophil rolling triggers Mrp8/14 secretion. Released MRP8/14 in turn activates a TLR4-mediated, Rap1-GTPase-dependent pathway of rapid ß2 integrin activation in neutrophils. This extracellular activation loop reduces leukocyte rolling velocity and stimulates adhesion. Thus, we identify Mrp8/14 and TLR4 as important modulators of the leukocyte recruitment cascade during inflammation in vivo.
Asunto(s)
Antígenos CD18/metabolismo , Calgranulina A/metabolismo , Calgranulina B/metabolismo , Adhesión Celular/fisiología , Rodamiento de Leucocito/fisiología , Neutrófilos/fisiología , Animales , Antígenos CD18/genética , Calgranulina A/genética , Calgranulina B/genética , Regulación de la Expresión Génica , Receptores de Hialuranos/genética , Receptores de Hialuranos/metabolismo , Inflamación/inducido químicamente , Inflamación/metabolismo , Macrófagos/fisiología , Masculino , Ratones , Ratones Noqueados , Unión ProteicaRESUMEN
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.