RESUMEN
Individuals with the Bombay phenotype (Oh) in the ABO blood group system do not express the H, A, and B antigens but have no clinical symptoms. Bombay phenotype with clinical symptoms has been described in leukocyte adhesion deficiency type II (LAD II), a fucosylation disorder caused by mutations in SLC35C1. Only few LAD II patients have been described so far. Here we describe an additional patient, a 22-year old male, born to unrelated parents, presenting with inflammatory skin disease, periodontitis, growth, and mental retardation, admitted to the department of dentistry for treatment under general anesthesia. Pre-operative routine investigations revealed the presence of the Bombay phenotype (Oh). Genomic sequencing identified two novel triplet deletions of the SLC35C1 gene. Functional investigations confirmed the diagnosis of LAD II. Therapy with oral fucose led to the disappearance of the chronic skin infections and improvements in behavior and attention span.
Asunto(s)
Síndrome de Deficiencia de Adhesión del Leucocito/diagnóstico , Sistema del Grupo Sanguíneo ABO , Adulto , Tipificación y Pruebas Cruzadas Sanguíneas , Eritrocitos , Fucosa/uso terapéutico , Humanos , Síndrome de Deficiencia de Adhesión del Leucocito/sangre , Síndrome de Deficiencia de Adhesión del Leucocito/tratamiento farmacológico , Síndrome de Deficiencia de Adhesión del Leucocito/genética , Leucocitos , Masculino , Proteínas de Transporte de Monosacáridos/genética , Adulto JovenRESUMEN
Beyond its well-established roles in mediating leukocyte rolling, E-selectin is emerging as a multifunctional receptor capable of inducing integrin activation in neutrophils, and of regulating various biological processes in hematopoietic precursors. Although these effects suggest important homeostatic contributions of this selectin in the immune and hematologic systems, the ligands responsible for transducing these effects in different leukocyte lineages are not well defined. We have characterized mice deficient in E-selectin ligand-1 (ESL-1), or in both P-selectin glycoprotein-1 (PSGL-1) and ESL-1, to explore and compare the contributions of these glycoproteins in immune and hematopoietic cell trafficking. In the steady state, ESL-1 deficiency resulted in a moderate myeloid expansion that became more prominent when both glycoproteins were eliminated. During inflammation, PSGL-1 dominated E-selectin binding, rolling, integrin activation, and extravasation of mature neutrophils, but only the combined deficiency in PSGL-1 and ESL-1 completely abrogated leukocyte recruitment. Surprisingly, we find that the levels of ESL-1 were strongly elevated in hematopoietic progenitor cells. These elevations correlated with a prominent function of ESL-1 for E-selectin binding and for migration of hematopoietic progenitor cells into the bone marrow. Our results uncover dominant roles for ESL-1 in the immature compartment, and a functional shift toward PSGL-1 dependence in mature neutrophils.
Asunto(s)
Células Madre Hematopoyéticas/inmunología , Inflamación/inmunología , Receptores de Factores de Crecimiento de Fibroblastos/inmunología , Sialoglicoproteínas/inmunología , Animales , Western Blotting , Médula Ósea/inmunología , Médula Ósea/metabolismo , Movimiento Celular/inmunología , Selectina E/metabolismo , Femenino , Citometría de Flujo , Células Madre Hematopoyéticas/metabolismo , Inflamación/genética , Inflamación/metabolismo , Rodamiento de Leucocito/genética , Rodamiento de Leucocito/inmunología , Leucocitos/inmunología , Leucocitos/metabolismo , Masculino , Glicoproteínas de Membrana/deficiencia , Glicoproteínas de Membrana/genética , Glicoproteínas de Membrana/inmunología , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Neutrófilos/inmunología , Neutrófilos/metabolismo , Peritonitis/genética , Peritonitis/inmunología , Peritonitis/metabolismo , Unión Proteica/inmunología , Receptores de Factores de Crecimiento de Fibroblastos/deficiencia , Receptores de Factores de Crecimiento de Fibroblastos/genética , Sialoglicoproteínas/deficiencia , Sialoglicoproteínas/genéticaRESUMEN
Selectins are carbohydrate-binding adhesion molecules that are required for leukocyte trafficking to secondary lymphoid organs and to sites of infection. They interact with fucosylated and sialylated ligands bearing sialyl-Lewis X as a minimal carbohydrate structure. With this in mind, it should be expected that individuals with deficient fucosylation or sialylation show immunodeficiency. However, as this review shows, the picture appears to be more complex and more interesting. Although there are only few patients with such glycosylation defects, they have turned out to be very instructive for our understanding of the functions of fucosylation and sialylation in immunity, development and hemostasis.
Asunto(s)
Trastornos Congénitos de Glicosilación/inmunología , Fucosiltransferasas/metabolismo , Leucocitos/metabolismo , Selectinas/metabolismo , Anciano , Animales , Adhesión Celular , Moléculas de Adhesión Celular , Trastornos Congénitos de Glicosilación/genética , Trastornos Congénitos de Glicosilación/patología , Fucosa/metabolismo , Fucosiltransferasas/genética , Glicosilación , Humanos , Lactante , Leucocitos/inmunología , Ligandos , Masculino , RatonesRESUMEN
We describe a novel type of human thrombocytopenia characterized by the appearance of giant platelets and variable neutropenia. Searching for the molecular defect, we found that neutrophils had strongly reduced sialyl-Lewis X and increased Lewis X surface expression, pointing to a deficiency in sialylation. We show that the glycosylation defect is restricted to α2,3-sialylation and can be detected in platelets, neutrophils, and monocytes. Platelets exhibited a distorted structure of the open canalicular system, indicating defective platelet generation. Importantly, patient platelets, but not normal platelets, bound to the asialoglycoprotein receptor (ASGP-R), a liver cell-surface protein that removes desialylated thrombocytes from the circulation in mice. Taken together, this is the first type of human thrombocytopenia in which a specific defect of α2,3-sialylation and an induction of platelet binding to the liver ASGP-R could be detected.
Asunto(s)
Ácido N-Acetilneuramínico/metabolismo , Oligosacáridos/metabolismo , Trombocitopenia/metabolismo , Trombocitopenia/patología , Animales , Receptor de Asialoglicoproteína/metabolismo , Plaquetas/metabolismo , Plaquetas/patología , Plaquetas/ultraestructura , Niño , Femenino , Granulocitos/metabolismo , Humanos , Interleucina-8/metabolismo , Hígado/metabolismo , Ratones , Mutación/genética , Neutropenia/complicaciones , Neutropenia/patología , Proteínas de Transporte de Nucleótidos/genética , Fenotipo , Unión Proteica , Selectinas/metabolismo , Antígeno Sialil Lewis X , Trombocitopenia/complicacionesRESUMEN
von Willebrand factor (VWF) is an important player in hemostasis but has also been suggested to promote inflammatory processes. Gene ablation of VWF causes a simultaneous defect in P-selectin expression making it difficult to identify VWF-specific functions. Therefore, we analyzed whether blocking antibodies against VWF would be able to interfere with neutrophil extravasation. We found that these antibodies inhibited neutrophil recruitment into thioglycollate-inflamed peritoneum and KC-stimulated cremaster by approximately 50%. Whereas platelet-VWF was not involved, the contribution of VWF to granulocyte recruitment was strictly dependent on the presence of platelets and the accessibility of their VWF-receptor glycoprotein Ib. Surprisingly, platelet P-selectin was largely dispensable for leukocyte extravasation, in agreement with our observation that anti-VWF antibodies did not affect leukocyte rolling and adhesion. Searching for possible effects downstream of leukocyte capture, we found that anti-VWF antibodies significantly inhibited thioglycollate-induced vascular permeability. The increase of permeability was independent of circulating granulocytes, showing that it was not a side effect of neutrophil diapedesis. Collectively, our results demonstrate that VWF-associated platelets strongly support neutrophil extravasation at a step downstream of leukocyte docking to the vessel wall. This step could be related to leukocyte diapedesis facilitated by destabilization of the endothelial barrier.
Asunto(s)
Movimiento Celular , Leucocitos/citología , Leucocitos/inmunología , Peritonitis/inmunología , Factor de von Willebrand/inmunología , Animales , Anticuerpos/inmunología , Plaquetas/inmunología , Permeabilidad Capilar , Ratones , Ratones Endogámicos C57BL , Neutrófilos/citología , Neutrófilos/inmunología , Selectina-P/inmunología , Peritoneo/inmunología , Complejo GPIb-IX de Glicoproteína Plaquetaria/inmunologíaRESUMEN
The beta(2) integrins are important for both transendothelial migration of leukocytes and T-cell activation during antigen presentation. In T cells, triggering of leukocyte functional antigen-1 (LFA-1) is required for full activation and T-helper (Th)1/Th2 differentiation. We used CD18-deficient (CD18(-/-)) mice to examine the role of LFA-1 in the activation of T cells. Compared with wild-type controls, CD18(-/-) T cells proliferated normally when stimulated with antibodies against CD3 and CD28, but secreted significantly less IFN-gamma and IL-2 than their wild-type counterparts. However, when T cells were stimulated with dendritic cells (DCs) that provide additional LFA-1 ligation, the proliferation of CD18(-/-) T cells was significantly reduced, whereas cytokine production remained impaired. The diminished proliferative capacity of CD18(-/-) T cells could be fully compensated for by additional triggering of the T-cell receptor, but not by additional stimulation through the costimulatory molecule, CD28. Thus, ligation of LFA-1 on T cells participates in regulation of Th1 cytokines in vivo. In addition, LFA-1 primarily exerts an effect as an enhancer of TCR signalling and does not facilitate classical costimulation.
Asunto(s)
Interferón gamma/metabolismo , Interleucina-2/metabolismo , Antígeno-1 Asociado a Función de Linfocito/metabolismo , Antígenos Estimulantes de Linfocito Menor/fisiología , Células TH1/citología , Células TH1/metabolismo , Animales , Anticuerpos/farmacología , Antígenos CD18/genética , Antígenos CD18/metabolismo , Antígenos CD28/inmunología , Complejo CD3/inmunología , Adhesión Celular/inmunología , Diferenciación Celular/inmunología , División Celular/inmunología , Células Dendríticas/citología , Células Dendríticas/inmunología , Molécula 1 de Adhesión Intercelular/metabolismo , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Ratones Mutantes , Transducción de Señal/inmunología , Células TH1/inmunologíaRESUMEN
Syndecan-1 (Sdc1) plays a major role in wound healing and modulates inflammatory responses. Sdc1 expression is reduced in lesions of patients with ulcerative colitis. The aim of this study was to investigate the role of Sdc1 in murine dextran sodium sulfate (DSS)-induced colitis. DSS colitis was induced in Sdc1-deficient (knockout (KO)) and wild-type mice by oral administration of 3% DSS. KO mice exhibited a significantly increased lethality as compared with wild-type controls (61 versus 5%, P < 0.05). Impaired mucosal healing and prolonged recruitment of inflammatory cells in KO mice were accompanied by significant up-regulation of tumor necrosis factor-alpha, CC chemokine ligand 3/macrophage inflammatory protein-1alpha, and vascular cell adhesion molecule-1, as determined by histological correlation between 0 and 15 days after colitis induction, TaqMan low-density array analysis, and quantitative real-time PCR. Treatment from days 7 through 14 with enoxaparin, a functional analogue of the Sdc1 heparan sulfate chains, significantly reduced lethality of KO mice due to DSS-induced colitis, which was correlated with improved mucosal healing. In vitro, Sdc1-deficient polymorphonuclear cells displayed increased adhesion to endothelial cells and intercellular adhesion molecule-1, and enoxaparin reverted adhesion to wild-type levels. Small interfering RNA-mediated knockdown of Sdc1 expression resulted in reduced basic fibroblast growth factor-mediated mitogen-activated protein kinase signaling and reduced Caco-2 cell proliferation. We conclude that Sdc1 has a protective effect during experimental colitis. The modification of missing Sdc1 function by heparin analogues may emerge as a promising anti-inflammatory approach.
Asunto(s)
Colitis/tratamiento farmacológico , Enoxaparina/uso terapéutico , Sindecano-1/deficiencia , Animales , Células CACO-2 , Adhesión Celular/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Colitis/genética , Colitis/patología , Sulfato de Dextran , Factor 2 de Crecimiento de Fibroblastos/farmacología , Regulación de la Expresión Génica/efectos de los fármacos , Técnicas de Silenciamiento del Gen , Humanos , Inflamación/genética , Molécula 1 de Adhesión Intercelular/metabolismo , Intestinos/efectos de los fármacos , Intestinos/patología , Tejido Linfoide/efectos de los fármacos , Tejido Linfoide/metabolismo , Sistema de Señalización de MAP Quinasas/efectos de los fármacos , Ratones , Neutrófilos/citología , Neutrófilos/efectos de los fármacos , ARN Interferente Pequeño/metabolismo , Sindecano-1/genética , Sindecano-1/metabolismo , Cicatrización de Heridas/efectos de los fármacosRESUMEN
The C-type lectin dendritic cell-specific intercellular adhesion molecule-3 grabbing nonintegrin (DC-SIGN) mediates the innate immune recognition of microbial carbohydrates. We investigated the function of this molecule in the host response to pathogens in vivo, by generating mouse lines lacking the DC-SIGN homologues SIGNR1, SIGNR3, and SIGNR5. Resistance to Mycobacterium tuberculosis was impaired only in SIGNR3-deficient animals. SIGNR3 was expressed in lung phagocytes during infection, and interacted with M. tuberculosis bacilli and mycobacterial surface glycoconjugates to induce secretion of critical host defense inflammatory cytokines, including tumor necrosis factor (TNF). SIGNR3 signaling was dependent on an intracellular tyrosine-based motif and the tyrosine kinase Syk. Thus, the mouse DC-SIGN homologue SIGNR3 makes a unique contribution to protection of the host against a pulmonary bacterial pathogen.
Asunto(s)
Moléculas de Adhesión Celular/fisiología , Lectinas Tipo C/fisiología , Receptores de Superficie Celular/fisiología , Tuberculosis/inmunología , Animales , Antígenos CD/fisiología , Quinasas MAP Reguladas por Señal Extracelular/fisiología , Femenino , Glicoconjugados/metabolismo , Interleucina-6/biosíntesis , Lipopolisacáridos/metabolismo , Pulmón/inmunología , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , FN-kappa B/fisiología , Proteínas Proto-Oncogénicas c-raf/fisiología , Transducción de Señal , Receptor Toll-Like 2/fisiología , Factor de Necrosis Tumoral alfa/biosíntesisRESUMEN
The cell surface heparan sulfate proteoglycan syndecan-1 (CD138) modulates the activity of chemokines, cytokines, integrins, and other adhesion molecules which play important roles in the regulation of inflammation. We have previously shown that syndecan-1-deficient murine leukocytes display increased interactions with endothelial cells and increased diapedesis in vivo and in vitro. In this study, we demonstrate that syndecan-1 has an important function as a negative modulator in the murine contact allergy model of oxazolone-mediated delayed-type hypersensitivity (DTH). Following elicitation of the DTH response, syndecan-1-deficient mice showed an increase in leukocyte recruitment, resulting in an increased and prolonged edema formation. Expression of the cytokines TNF-alpha and IL-6 of the chemokines CCL5/RANTES and CCL-3/MIP-1alpha and of the adhesion molecule ICAM-1 were significantly increased in syndecan-1-deficient compared with wild-type mice. In wild-type mice, syndecan-1 mRNA and protein expression was reduced during the DTH response. The differentially increased adhesion of syndecan-1-deficient leukocytes to ICAM-1 was efficiently inhibited in vitro by CD18-blocking Abs, which emerges as one mechanistic explanation for the anti-inflammatory effects of syndecan-1. Collectively, our results show an important role of syndecan-1 in the contact DTH reaction, identifying syndecan-1 as a novel target in anti-inflammatory therapy.
Asunto(s)
Hipersensibilidad Tardía/inmunología , Sindecano-1/inmunología , Animales , Movimiento Celular/inmunología , Epítopos/inmunología , Heparitina Sulfato/inmunología , Hipersensibilidad Tardía/genética , Hipersensibilidad Tardía/metabolismo , Hipersensibilidad Tardía/patología , Molécula 1 de Adhesión Intercelular/metabolismo , Leucocitos/citología , Leucocitos/inmunología , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Regulación hacia ArribaRESUMEN
Total synthesis through block glycosylation and selective chemical O-sulfation of tyrosine residues yielded the glycopeptide recognition domain A (X=SO(3) (-)) of the P-selectin glycoprotein ligand 1, in which the terminal sialic acid of the complex hexasaccharide side chain was replaced by (S)-cyclohexyl lactic acid. In binding assays the O-sulfated structure A showed high affinity towards P-selectin, the non-sulfated towards E-selectin.
Asunto(s)
Selectina E/química , Glicopéptidos/química , Glicoproteínas de Membrana/química , Selectina-P/química , Animales , Glicopéptidos/síntesis química , Glicosilación , Humanos , Glicoproteínas de Membrana/síntesis química , Ratones , Estructura Terciaria de Proteína , Sulfatos/químicaRESUMEN
The relationship between intermembrane spacing, adhesion efficiency, and lateral organization of adhesion receptors has not been established for any adhesion system. We have utilized the CD2 ligand CD48 with two (wild type CD48 (CD48-WT)), four (CD48-CD2), or five (CD48-CD22) Ig-like domains. CD48-WT was 10-fold more efficient in mediating adhesion than CD48-CD2 or CD48-CD22. Electron tomography of contact areas with planar bilayers demonstrated average intermembrane spacing of 12.8 nm with CD48-WT, 14.7 nm with CD48-CD2, and 15.6 nm with CD48-CD22. Both CD48-CD2 and CD48-CD22 chimeras segregated completely from CD48-WT in mixed contact areas. In contrast, CD48-CD2 and CD48-CD22 co-localized when mixed contacts were formed. Confocal imaging of immunological synapses formed between primary T lymphocytes and Chinese hamster ovary cells presenting major histocompatibility complex-peptide complexes, and different forms of CD48 demonstrated that CD48-CD2 and CD48-CD22 induce an eccentric CD2/T cell antigen receptor cluster. We propose that this reorganization of the immunological synapse sequesters the T cell antigen receptor in a location where it cannot interact with its ligand and dramatically reduces T cell sensitivity.
Asunto(s)
Antígenos CD/química , Antígenos CD2/química , Sinapsis Inmunológicas/fisiología , Linfocitos T/metabolismo , Animales , Antígeno CD48 , Células CHO , Adhesión Celular , Proliferación Celular , Cricetinae , Cricetulus , Tomografía con Microscopio Electrónico/métodos , Citometría de Flujo , Ratones , Microscopía Fluorescente/métodos , Lectina 2 Similar a Ig de Unión al Ácido Siálico/químicaRESUMEN
Leukocyte adhesion deficiency II (LAD II), also known as congenital disorder of glycosylation IIc (CDG-IIc), is a human disease in which a defective GDP-fucose transporter (SLC35C1) causes developmental defects and an immunodeficiency that is based on the lack of fucosylated selectin ligands. Since the study of in vivo leukocyte trafficking in patients with LAD II is experimentally limited, we analyzed this process in mice deficient for Slc35c1. We found that E-, L-, and P-selectin-dependent leukocyte rolling in cremaster muscle venules was virtually absent. This was accompanied by a strong but not complete decrease in firm leukocyte adhesion. Moreover, neutrophil migration to the inflamed peritoneum was strongly reduced by 89%. Previous reports showed surprisingly normal lymphocyte functions in LAD II, which indicated sufficient lymphocyte trafficking to secondary lymphoid organs. We now found that while lymphocyte homing to lymph nodes was reduced to 1% to 2% in Slc35c1(-/-) mice, trafficking to the spleen was completely normal. In accordance with this, we found a defect in the humoral response to a T cell-dependent antigen in lymph nodes but not in the spleen. Taken together, Slc35c1(-/-) mice show strongly defective leukocyte trafficking but normal lymphocyte homing to the spleen, which may explain normal lymphocyte functions in LAD II.
Asunto(s)
Quimiotaxis de Leucocito , Síndrome de Deficiencia de Adhesión del Leucocito/inmunología , Proteínas de Transporte de Membrana/deficiencia , Animales , Adhesión Celular , Modelos Animales de Enfermedad , Rodamiento de Leucocito , Ganglios Linfáticos/patología , Ratones , Proteínas de Transporte de Monosacáridos , Músculo Esquelético/irrigación sanguínea , Neutrófilos/patología , Especificidad de Órganos , Bazo , Vénulas/citologíaRESUMEN
Dendritic cells (DCs) have a key role in both the generation of the immune response and the induction of tolerance to self-Ags. In this work, the possible role of P-selectin glycoprotein ligand 1 (PSGL-1) on the tolerogenic activity of human DCs was explored. We found that the engagement of PSGL-1 by P-selectin on DCs induced the expression of c-Fos, IDO, IL-10, and TGF-beta genes. Remarkably, stimulation of DCs through PSGL-1 with P-selectin enhanced their capability to generate CD4(+)CD25(+)Foxp3(+) regulatory T cells, which expressed high levels of TGF-beta1 mRNA, synthesized IL-10, and suppressed the proliferation of autologous CD4(+)CD25(-) T cells. Accordingly, we found that DCs from PSGL-1(-/-) mice expressed higher levels of MHC class II molecules, and exhibited an enhanced immunogenicity compared with wild-type mice. In addition, the percentage of CD4(+)CD25(+)Foxp3(+) regulatory T cells in the thymus of PSGL-1-deficient animals was significantly reduced. Our data reveal an unexpected role of PSGL-1 on the tolerogenic function of DCs, and the regulation of the immune response.
Asunto(s)
Tolerancia Inmunológica/inmunología , Glicoproteínas de Membrana/fisiología , Selectina-P/metabolismo , Animales , Células Cultivadas , Células Dendríticas/efectos de los fármacos , Células Dendríticas/inmunología , Femenino , Factores de Transcripción Forkhead/inmunología , Regulación de la Expresión Génica/genética , Indolamina-Pirrol 2,3,-Dioxigenasa/genética , Interleucina-10/genética , Masculino , Glicoproteínas de Membrana/biosíntesis , Glicoproteínas de Membrana/genética , Ratones , Ratones Endogámicos C57BL , Selectina-P/farmacología , Unión Proteica , Proteínas Proto-Oncogénicas c-fos/genética , ARN Mensajero/genética , Linfocitos T Reguladores/inmunología , Factor de Crecimiento Transformador beta/genética , Factor de Crecimiento Transformador beta1/genéticaRESUMEN
Modification of glycoproteins by the attachment of fucose residues is widely distributed in nature. The importance of fucosylation has recently been underlined by identification of the monogenetic inherited human disease "congenital disorder of glycosylation IIc," also termed "leukocyte adhesion deficiency II." Due to defective Golgi GDP-fucose transporter (SLC35C1) activity, patients show a hypofucosylation of glycoproteins and present clinically with mental and growth retardation, persistent leukocytosis, and severe infections. To investigate effects induced by the loss of fucosylated structures in different organs, we generated a mouse model for the disease by inactivating the Golgi GDP-transporter gene (Slc35c1). Lectin binding studies revealed a tremendous reduction of fucosylated glycoconjugates in tissues and isolated cells from Slc35c1(-/-) mice. Fucose treatment of cells from different organs led to partial normalization of the fucosylation state of glycoproteins, thereby indicating an alternative GDP-fucose transport mechanism. Slc35c1-deficient mice presented with severe growth retardation, elevated postnatal mortality rate, dilatation of lung alveoles, and hypocellular lymph nodes. In vitro and in vivo leukocyte adhesion and rolling assays revealed a severe impairment of P-, E-, and L-selectin ligand function. The diversity of these phenotypic aspects demonstrates the broad general impact of fucosylation in the mammalian organism.
Asunto(s)
Moléculas de Adhesión Celular/genética , Fucosa/metabolismo , Rodamiento de Leucocito/genética , Proteínas de Transporte de Membrana/deficiencia , Errores Innatos del Metabolismo/metabolismo , Modificación Traduccional de las Proteínas/genética , Animales , Adhesión Celular/genética , Moléculas de Adhesión Celular/metabolismo , Fucosa/genética , Glicosilación , Aparato de Golgi/enzimología , Aparato de Golgi/genética , Aparato de Golgi/patología , Trastornos del Crecimiento/enzimología , Trastornos del Crecimiento/genética , Leucocitosis/enzimología , Leucocitosis/genética , Leucocitosis/patología , Proteínas de Transporte de Membrana/metabolismo , Errores Innatos del Metabolismo/genética , Errores Innatos del Metabolismo/patología , Ratones , Ratones Noqueados , Proteínas de Transporte de MonosacáridosAsunto(s)
Adhesión Celular/efectos de los fármacos , Selectina E/química , Glicopéptidos/farmacología , Neutrófilos/efectos de los fármacos , Animales , Células Cultivadas , Selectina E/metabolismo , Glicopéptidos/síntesis química , Glicopéptidos/química , Antígenos del Grupo Sanguíneo de Lewis/química , Ligandos , Ratones , Neutrófilos/citología , Neutrófilos/metabolismoRESUMEN
BACKGROUND: The cell-associated proteoglycan syndecan-1 (Synd1) closely regulates inflammation and cell-matrix interactions during wound healing and tumorigenesis. The present study investigated whether Synd1 may also regulate cardiac inflammation, matrix remodeling, and function after myocardial infarction (MI). METHODS AND RESULTS: First, we showed increased protein and mRNA expression of Synd1 from 24 hours on, reaching its maximum at 7 days after MI and declining thereafter. Targeted deletion of Synd1 resulted in increased inflammation and accelerated, yet functionally adverse, infarct healing after MI. In concordance, adenoviral gene expression of Synd1 protected against exaggerated inflammation after MI, mainly by reducing transendothelial adhesion and migration of leukocytes, as shown in vitro. Increased inflammation in the absence of Synd1 resulted in increased monocyte chemoattractant protein-1 expression, increased activity of matrix metalloproteinase-2 and -9, and decreased activity of tissue transglutaminase, associated with increased collagen fragmentation and disorganization. Exaggerated inflammation and adverse matrix remodeling in the absence of Synd1 increased cardiac dilatation and impaired systolic function, whereas gene overexpression of Synd1 reduced inflammation and protected against cardiac dilatation and failure. CONCLUSIONS: Increased expression of Synd1 in the infarct protects against exaggerated inflammation and adverse infarct healing, thereby reducing cardiac dilatation and dysfunction after MI in mice.
Asunto(s)
Cardiomiopatía Dilatada/genética , Infarto del Miocardio/genética , Sindecano-1/genética , Sindecano-1/fisiología , Remodelación Ventricular/genética , Animales , Cardiomiopatía Dilatada/inmunología , Cardiomiopatía Dilatada/fisiopatología , Colágeno/genética , Citocinas/genética , Citocinas/inmunología , Modelos Animales de Enfermedad , Femenino , Expresión Génica , Corazón/fisiología , Leucocitos/inmunología , Masculino , Metaloproteinasa 2 de la Matriz/metabolismo , Metaloproteinasa 9 de la Matriz/metabolismo , Ratones , Ratones Endogámicos BALB C , Ratones Noqueados , Mutagénesis , Infarto del Miocardio/inmunología , Infarto del Miocardio/fisiopatología , Miocardio/enzimología , Miocardio/patología , ARN Mensajero/metabolismo , Sístole/genética , Remodelación Ventricular/inmunologíaRESUMEN
The beta2 integrins are important for transendothelial migration of leukocytes as well as for T-cell activation during antigen presentation. Despite abundant expression of beta2 integrins on antigen-presenting cells (APCs), their functional relevance for antigen presentation is completely unclear. We show here that dendritic cells (DCs) from CD18-deficient mice, which lack all functional beta2 integrins, have no defect in antigen presentation. Moreover, DCs from normal mice express inactive beta2 integrins that do not become activated on contact with T cells, at least in vitro. Pharmacologic activation of beta2 integrins on DCs results in a significant reduction of their T cell-activating capacity. This effect is mediated by Mac-1 (CD11b/CD18) on DCs because it could be reversed via blocking antibodies against CD18 and CD11b. Furthermore, the antigen-presenting capacity of macrophages, which express constitutively active beta2 integrins, is significantly enhanced on Mac-1 blockade. We therefore conclude that active CD11b/CD18 (Mac-1) on APCs directly inhibits T-cell activation.
Asunto(s)
Antígeno CD11b/fisiología , Antígenos CD18/fisiología , Células Dendríticas/inmunología , Activación de Linfocitos/inmunología , Antígeno de Macrófago-1/fisiología , Linfocitos T/inmunología , Animales , Presentación de Antígeno/inmunología , Antígenos CD18/genética , Antígenos CD18/metabolismo , Células Cultivadas , Inmunofenotipificación , Macrófagos/inmunología , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Ratones NoqueadosRESUMEN
Immature dendritic cells (DC) reside in tissues where they initiate immune responses by taking up foreign antigens. Since DC have a limited tissue half-life, the DC pool in tissues has to be replenished constantly. This implies that precursor/immature DC must be able to cross non-activated endothelium using as yet unknown mechanisms. Here we show that immature, but not mature bone marrow-derived murine DC migrate across resting endothelial monolayers in vitro. We find that endothelial intercellular adhesion molecule-2 (ICAM-2) is a major player in transendothelial migration (TEM) of immature DC, accounting for at least 41% of TEM. Surprisingly, the ICAM-2-mediated TEM was independent of beta2-integrins, the known ICAM-2 ligands, since neither blocking of beta2-integrins with antibodies nor the use of CD18-deficient DC affected the ICAM-2-specific TEM. In humans, the C-type lectin DC-specific ICAM-3-grabbing nonintegrin (DC-SIGN) was shown to interact with ICAM-2, suggesting a similar role in mice. However, we find that none of the murine DC-SIGN homologues mDC-SIGN, murine DC-SIGN-related molecule-1 (mSIGN-R1) and mSIGN-R3 is expressed on the surface of bone marrow-derived mouse DC. Taken together, this study shows that ICAM-2 strongly supports transmigration of immature DC across resting endothelium by interacting with ligands that are distinct from beta2-integrins and DC-SIGN homologues.
Asunto(s)
Antígenos CD/metabolismo , Antígenos CD18/metabolismo , Moléculas de Adhesión Celular/metabolismo , Movimiento Celular/inmunología , Células Dendríticas/metabolismo , Endotelio Vascular/metabolismo , Lectinas Tipo C/metabolismo , Receptores de Superficie Celular/metabolismo , Animales , Western Blotting , Diferenciación Celular/inmunología , Clonación Molecular , Células Dendríticas/citología , Células Dendríticas/inmunología , Femenino , Citometría de Flujo , Humanos , Inmunoprecipitación , Ratones , Ratones Mutantes , Reacción en Cadena de la PolimerasaRESUMEN
Leukocyte adhesion deficiency II (LAD II) belongs to a group of human congenital diseases in which the interactions of leukocytes with the vascular endothelium are strongly impaired. LAD II is based on a defect in the synthesis of fucosylated glycostructures. This leads to an immunodeficiency owing to the absence of functional selectin ligands and to strong psychomotor defects, as a result of as-yet unknown reasons. In this review we focused on the current controversies, and open questions that have arisen from recent studies on the genetic defect, therapy and the basis of psychomotor defects in LAD II.